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英文The road (highway)The road is one kind of linear construction used for travel。

It is made of the roadbed，the road surface, the bridge, the culvert and the tunnel. In addition, it also has the crossing of lines, the protective project and the traffic engineering and the route facility。

The roadbed is the base of road surface, road shoulder，side slope, side ditch foundations. It is stone material structure, which is designed according to route's plane position .The roadbed, as the base of travel, must guarantee that it has the enough intensity and the stability that can prevent the water and other natural disaster from corroding.The road surface is the surface of road. It is single or complex structure built with mixture。

The road surface require being smooth，having enough intensity，good stability and anti—slippery function. The quality of road surface directly affects the safe, comfort and the traffic。

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A Design and Implementation of Active NetworkSocket ProgrammingK.L. Eddie Law, Roy LeungThe Edward S. Rogers Sr. Department of Electrical and Computer EngineeringUniversity of TorontoToronto, Canadaeddie@, roy.leung@utoronto.caAbstract—The concept of programmable nodes and active networks introduces programmability into communication networks. Code and data can be sent and modified on their ways to destinations. Recently, various research groups have designed and implemented their own design platforms. Each design has its own benefits and drawbacks. Moreover, there exists an interoperability problem among platforms. As a result, we introduce a concept that is similar to the network socket programming. We intentionally establish a set of simple interfaces for programming active applications. This set of interfaces, known as Active Network Socket Programming (ANSP), will be working on top of all other execution environments in future. Therefore, the ANSP offers a concept that is similar to “write once, run everywhere.” It is an open programming model that active applications can work on all execution environments. It solves the heterogeneity within active networks. This is especially useful when active applications need to access all regions within a heterogeneous network to deploy special service at critical points or to monitor the performance of the entire networks. Instead of introducing a new platform, our approach provides a thin, transparent layer on top of existing environments that can be easily installed for all active applications.Keywords-active networks; application programming interface; active network socket programming;I. I NTRODUCTIONIn 1990, Clark and Tennenhouse [1] proposed a design framework for introducing new network protocols for the Internet. Since the publication of that position paper, active network design framework [2, 3, 10] has slowly taken shape in the late 1990s. The active network paradigm allows program code and data to be delivered simultaneously on the Internet. Moreover, they may get executed and modified on their ways to their destinations. At the moment, there is a global active network backbone, the ABone, for experiments on active networks. Apart from the immaturity of the executing platform, the primary hindrance on the deployment of active networks on the Internet is more on the commercially related issues. For example, a vendor may hesitate to allow network routers to run some unknown programs that may affect their expected routing performance. As a result, alternatives were proposed to allow active network concept to operate on the Internet, such as the application layer active networking (ALAN) project [4] from the European research community. In the ALAN project, there are active server systems located at different places in the networks and active applications are allowed to run in these servers at the application layer. Another potential approach from the network service provider is to offer active network service as the premium service class in the networks. This service class should provide the best Quality of Service (QoS), and allow the access of computing facility in routers. With this approach, the network service providers can create a new source of income.The research in active networks has been progressing steadily. Since active networks introduce programmability on the Internet, appropriate executing platforms for the active applications to execute should be established. These operating platforms are known as execution environments (EEs) and a few of them have been created, e.g., the Active Signaling Protocol (ASP) [12] and the Active Network Transport System (ANTS) [11]. Hence, different active applications can be implemented to test the active networking concept.With these EEs, some experiments have been carried out to examine the active network concept, for example, the mobile networks [5], web proxies [6], and multicast routers [7]. Active networks introduce a lot of program flexibility and extensibility in networks. Several research groups have proposed various designs of execution environments to offer network computation within routers. Their performance and potential benefits to existing infrastructure are being evaluated [8, 9]. Unfortunately, they seldom concern the interoperability problems when the active networks consist of multiple execution environments. For example, there are three EEs in ABone. Active applications written for one particular EE cannot be operated on other platforms. This introduces another problem of resources partitioning for different EEs to operate. Moreover, there are always some critical network applications that need to run under all network routers, such as collecting information and deploying service at critical points to monitor the networks.In this paper, a framework known as Active Network Socket Programming (ANSP) model is proposed to work with all EEs. It offers the following primary objectives.• One single programming interface is introduced for writing active applications.• Since ANSP offers the programming interface, the design of EE can be made independent of the ANSP.This enables a transparency in developing andenhancing future execution environments.• ANSP addresses the interoperability issues among different execution environments.• Through the design of ANSP, the pros and cons of different EEs will be gained. This may help design abetter EE with improved performance in future.The primary objective of the ANSP is to enable all active applications that are written in ANSP can operate in the ABone testbed . While the proposed ANSP framework is essential in unifying the network environments, we believe that the availability of different environments is beneficial in the development of a better execution environment in future. ANSP is not intended to replace all existing environments, but to enable the studies of new network services which are orthogonal to the designs of execution environments. Therefore, ANSP is designed to be a thin and transparent layer on top of all execution environments. Currently, its deployment relies on automatic code loading with the underlying environments. As a result, the deployment of ANSP at a router is optional and does not require any change to the execution environments.II. D ESIGN I SSUES ON ANSPThe ANSP unifies existing programming interfaces among all EEs. Conceptually, the design of ANSP is similar to the middleware design that offers proper translation mechanisms to different EEs. The provisioning of a unified interface is only one part of the whole ANSP platform. There are many other issues that need to be considered. Apart from translating a set of programming interfaces to other executable calls in different EEs, there are other design issues that should be covered, e.g., • a unified thread library handles thread operations regardless of the thread libraries used in the EEs;• a global soft-store allows information sharing among capsules that may execute over different environmentsat a given router;• a unified addressing scheme used across different environments; more importantly, a routing informationexchange mechanism should be designed across EEs toobtain a global view of the unified networks;• a programming model that should be independent to any programming languages in active networks;• and finally, a translation mechanism to hide the heterogeneity of capsule header structures.A. Heterogeneity in programming modelEach execution environment provides various abstractions for its services and resources in the form of program calls. The model consists of a set of well-defined components, each of them has its own programming interfaces. For the abstractions, capsule-based programming model [10] is the most popular design in active networks. It is used in ANTS [11] and ASP [12], and they are being supported in ABone. Although they are developed based on the same capsule model, their respective components and interfaces are different. Therefore, programs written in one EE cannot run in anther EE. The conceptual views of the programming models in ANTS and ASP are shown in Figure 1.There are three distinct components in ANTS: application, capsule, and execution environment. There exist user interfaces for the active applications at only the source and destination routers. Then the users can specify their customized actions to the networks. According to the program function, the applications send one or more capsules to carry out the operations. Both applications and capsules operate on top of an execution environment that exports an interface to its internal programming resources. Capsule executes its program at each router it has visited. When it arrives at its destination, the application at destination may either reply it with another capsule or presents this arrival event to the user. One drawback with ANTS is that it only allows “bootstrap” application.Figure 1. Programming Models in ASP and ANTS.In contrast, ASP does not limit its users to run “bootstrap” applications. Its program interfaces are different from ANTS, but there are also has three components in ASP: application client, environment, and AAContext. The application client can run on active or non-active host. It can start an active application by simply sending a request message to the EE. The client presents information to users and allows its users to trigger actions at a nearby active router. AAContext is the core of the network service and its specification is divided into two parts. One part specifies its actions at its source and destination routers. Its role is similar to that of the application in ANTS, except that it does not provide a direct interface with the user. The other part defines its actions when it runs inside the active networks and it is similar to the functional behaviors of a capsule in ANTS.In order to deal with the heterogeneity of these two models, ANSP needs to introduce a new set of programming interfaces and map its interfaces and execution model to those within the routers’ EEs.B. Unified Thread LibraryEach execution environment must ensure the isolation of instance executions, so they do not affect each other or accessThe authors appreciate the Nortel Institute for Telecommunications (NIT) at the University of Toronto to allow them to access the computing facilitiesothers’ information. There are various ways to enforce the access control. One simple way is to have one virtual machine for one instance of active applications. This relies on the security design in the virtual machines to isolate services. ANTS is one example that is using this method. Nevertheless, the use of multiple virtual machines requires relatively large amount of resources and may be inefficient in some cases. Therefore, certain environments, such as ASP, allow network services to run within a virtual machine but restrict the use of their services to a limited set of libraries in their packages. For instance, ASP provides its thread library to enforce access control. Because of the differences in these types of thread mechanism, ANSP devises a new thread library to allow uniform accesses to different thread mechanisms.C. Soft-StoreSoft-store allows capsule to insert and retrieve information at a router, thus allowing more than one capsules to exchange information within a network. However, problem arises when a network service can execute under different environments within a router. The problem occurs especially when a network service inserts its soft-store information in one environment and retrieves its data at a later time in another environment at the same router. Due to the fact that execution environments are not allowed to exchange information, the network service cannot retrieve its previous data. Therefore, our ANSP framework needs to take into account of this problem and provides soft-store mechanism that allows universal access of its data at each router.D. Global View of a Unified NetworkWhen an active application is written with ANSP, it can execute on different environment seamlessly. The previously smaller and partitioned networks based on different EEs can now be merging into one large active network. It is then necessary to advise the network topology across the networks. However, different execution environments have different addressing schemes and proprietary routing protocols. In order to merge these partitions together, ANSP must provide a new unified addressing scheme. This new scheme should be interpretable by any environments through appropriate translations with the ANSP. Upon defining the new addressing scheme, a new routing protocol should be designed to operate among environments to exchange topology information. This allows each environment in a network to have a complete view of its network topology.E. Language-Independent ModelExecution environment can be programmed in any programming language. One of the most commonly used languages is Java [13] due to its dynamic code loading capability. In fact, both ANTS and ASP are developed in Java. Nevertheless, the active network architecture shown in Figure 2 does not restrict the use of additional environments that are developed in other languages. For instance, the active network daemon, anted, in Abone provides a workspace to execute multiple execution environments within a router. PLAN, for example, is implemented in Ocaml that will be deployable on ABone in future. Although the current active network is designed to deploy multiple environments that can be in any programming languages, there lacks the tool to allow active applications to run seamlessly upon these environments. Hence, one of the issues that ANSP needs to address is to design a programming model that can work with different programming languages. Although our current prototype only considers ANTS and ASP in its design, PLAN will be the next target to address the programming language issue and to improve the design of ANSP.Figure 2. ANSP Framework Model.F. Heterogeneity of Capsule Header StructureThe structures of the capsule headers are different in different EEs. They carries capsule-related information, for example, the capsule types, sources and destinations. This information is important when certain decision needs to be made within its target environment. A unified model should allow its program code to be executed on different environments. However, the capsule header prevents different environments to interpret its information successfully. Therefore, ANSP should carry out appropriate translation to the header information before the target environment receives this capsule.III. ANSP P ROGRAMMING M ODELWe have outlined the design issues encountered with the ANSP. In the following, the design of the programming model in ANSP will be discussed. This proposed framework provides a set of unified programming interfaces that allows active applications to work on all execution environments. The framework is shown in Figure 2. It is composed of two layers integrated within the active network architecture. These two layers can operate independently without the other layer. The upper layer provides a unified programming model to active applications. The lower layer provides appropriate translation procedure to the ANSP applications when it is processed by different environments. This service is necessary because each environment has its own header definition.The ANSP framework provides a set of programming calls which are abstractions of ANSP services and resources. A capsule-based model is used for ANSP, and it is currently extended to map to other capsule-based models used in ANTSand ASP. The mapping possibility to other models remains as our future works. Hence, the mapping technique in ANSP allows any ANSP applications to access the same programming resources in different environments through a single set of interfaces. The mapping has to be done in a consistent and transparent manner. Therefore, the ANSP appears as an execution environment that provides a complete set of functionalities to active applications. While in fact, it is an overlay structure that makes use of the services provided from the underlying environments. In the following, the high-level functional descriptions of the ANSP model are described. Then, the implementations will be discussed. The ANSP programming model is based upon the interactions between four components: application client , application stub , capsule , and active service base.Figure 3. Information Flow with the ANSP.•Application Client : In a typical scenario, an active application requires some means to present information to its users, e.g., the state of the networks. A graphical user interface (GUI) is designed to operate with the application client if the ANSP runs on a non-active host.•Application Stub : When an application starts, it activates the application client to create a new instance of application stub at its near-by active node. There are two responsibilities for the application stub. One of them is to receive users’ instructions from the application client. Another one is to receive incoming capsules from networks and to perform appropriate actions. Typically, there are two types of actions, thatare, to reply or relay in capsules through the networks, or to notify the users regarding the incoming capsule. •Capsule : An active application may contain several capsule types. Each of them carries program code (also referred to as forwarding routine). Since the application defines a protocol to specify the interactions among capsules as well as the application stubs. Every capsule executes its forwarding routine at each router it visits along the path between the source and destination.•Active Service Base : An active service base is designed to export routers’ environments’ services and execute program calls from application stubs and capsules from different EEs. The base is loaded automatically at each router whenever a capsule arrives.The interactions among components within ANSP are shown in Figure 3. The designs of some key components in the ANSP will be discussed in the following subsections. A. Capsule (ANSPCapsule)ANSPXdr decode () ANSPXdr encode () int length ()Boolean execute ()New types of capsule are created by extending the abstract class ANSPCapsule . New extensions are required to define their own forwarding routines as well as their serialization procedures. These methods are indicated below:The execution of a capsule in ANSP is listed below. It is similar to the process in ANTS.1. A capsule is in serial binary representation before it issent to the network. When an active router receives a byte sequence, it invokes decode() to convert the sequence into a capsule. 2. The router invokes the forwarding routine of thecapsule, execute(). 3. When the capsule has finished its job and forwardsitself to its next hop by calling send(), this call implicitly invokes encode() to convert the capsule into a new serial byte representation. length() isused inside the call of encode() to determine the length of the resulting byte sequence. ANSP provides a XDR library called ANSPXdr to ease the jobs of encoding and decoding.B. Active Service Base (ANSPBase)In an active node, the Active Service Base provides a unified interface to export the available resources in EEs for the rest of the ANSP components. The services may include thread management, node query, and soft-store operation, as shown in Table 1.TABLE I. ACTIVE SERVICE BASE FUNCTION CALLSFunction Definition Descriptionboolean send (Capsule, Address) Transmit a capsule towards its destination using the routing table of theunderlying environment.ANSPAddress getLocalHost () Return address of the local host as an ANSPAddress structure. This isuseful when a capsule wants to check its current location.boolean isLocal (ANSPAddress) Return true if its input argument matches the local host’s address andreturn false otherwise.createThread () Create a new thread that is a class ofANSPThreadInterface (discussed later in Section VIA “Unified Thread Abstraction”).putSStore (key, Object) Object getSStore (key) removeSStore (key)The soft-store operations are provided by putSStore(), getSSTore(), and removeSStore(), and they put, retrieve, and remove data respectively. forName (PathName) Supported in ANSP to retrieve a classobject corresponding to the given path name in its argument. This code retrieval may rely on the code loading mechanism in the environment whennecessary.C. Application Client (ANSPClient)boolean start (args[])boolean start (args[],runningEEs) boolean start (args[],startClient)boolean start (args[],startClient, runningEE)Application Client is an interface between users and the nearby active source router. It does the following responsibilities.1. Code registration: It may be necessary to specify thelocation and name of the application code in some execution environments, e.g., ANTS. 2. Application initialization: It includes selecting anexecution environment to execute the application among those are available at the source router. Each active application can create an application client instance by extending the abstract class, ANSPClient . The extension inherits a method, start(), to automatically handle both the registration and initialization processes. All overloaded versions of start() accept a list of arguments, args , that are passed to the application stub during its initialization. An optional argument called runningEEs allows an application client to select a particular set of environment variables, specified by a list of standardized numerical environment ID, the ANEP ID, to perform code registration. If this argument is not specified, the default setting can only include ANTS and ASP. D. Application Stub (ANSPApplication)receive (ANSPCapsule)Application stubs reside at the source and destination routers to initialize the ANSP application after the application clients complete the initialization and registration processes. It is responsible for receiving and serving capsules from the networks as well as actions requested from the clients. A new instance is created by extending the application client abstract class, ANSPApplication . This extension includes the definition of a handling routine called receive(), which is invoked when a stub receives a new capsule.IV. ANSP E XAMPLE : T RACE -R OUTEA testbed has been created to verify the design correctnessof ANSP in heterogeneous environments. There are three types of router setting on this testbed:1. Router that contains ANTS and a ANSP daemonrunning on behalf of ASP; 2. Router that contains ASP and a ANSP daemon thatruns on behalf of ANTS; 3. Router that contains both ASP and ANTS.The prototype is written in Java [11] with a traceroute testing program. The program records the execution environments of all intermediate routers that it has visited between the source and destination. It also measures the RTT between them. Figure 4 shows the GUI from the application client, and it finds three execution environments along the path: ASP, ANTS, and ASP. The execution sequence of the traceroute program is shown in Figure 5.Figure 4. The GUI for the TRACEROUTE Program.The TraceCapsule program code is created byextending the ANSPCapsule abstract class. When execute() starts, it checks the Boolean value of returning to determine if it is returning from the destination. It is set to true if TraceCapsule is traveling back to the source router; otherwise it is false . When traveling towards the destination, TraceCapsule keeps track of the environments and addresses of the routers it has visited in two arrays, path and trace , respectively. When it arrives at a new router, it calls addHop() to append the router address and its environment to these two arrays. When it finally arrives at the destination, it sets returning to false and forwards itself back to the source by calling send().When it returns to source, it invokes deliverToApp() to deliver itself to the application stub that has been running at the source. TraceCapsule carries information in its data field through the networks by executing encode() and decode(), which encapsulates and de-capsulates its data using External Data Representation (XDR) respectively. The syntax of ANSP XDR follows the syntax of XDR library from ANTS. length() in TraceCapsule returns the data length, or it can be calculated by using the primitive types in the XDRlibrary.Figure 5. Flow of the TRACEROUTE Capsules.V. C ONCLUSIONSIn this paper, we present a new unified layered architecture for active networks. The new model is known as Active Network Socket Programming (ANSP). It allows each active application to be written once and run on multiple environments in active networks. Our experiments successfully verify the design of ANSP architecture, and it has been successfully deployed to work harmoniously with ANTS and ASP without making any changes to their architectures. In fact, the unified programming interface layer is light-weighted and can be dynamically deployable upon request.R EFERENCES[1] D.D. Clark, D.L. Tennenhouse, “Architectural Considerations for a NewGeneration of Protocols,” in Proc. ACM Sigcomm’90, pp.200-208, 1990. [2] D. Tennenhouse, J. M. Smith, W. D. Sicoskie, D. J. Wetherall, and G. J.Minden, “A survey of active network research,” IEEE Communications Magazine , pp. 80-86, Jan 1997.[3] D. Wetherall, U. Legedza, and J. Guttag, “Introducing new internetservices: Why and how,” IEEE Network Magazine, July/August 1998. [4] M. Fry, A. Ghosh, “Application Layer Active Networking,” in ComputerNetworks , Vol.31, No.7, pp.655-667, 1999.[5] K. W. Chin, “An Investigation into The Application of Active Networksto Mobile Computing Environments”, Curtin University of Technology, March 2000.[6] S. Bhattacharjee, K. L. Calvert, and E. W. Zegura, “Self OrganizingWide-Area Network Caches”, Proc. IEEE INFOCOM ’98, San Francisco, CA, 29 March-2 April 1998.[7] L. H. Leman, S. J. Garland, and D. L. Tennenhouse, “Active ReliableMulticast”, Proc. IEEE INFOCOM ’98, San Francisco, CA, 29 March-2 April 1998.[8] D. Descasper, G. Parulkar, B. Plattner, “A Scalable, High PerformanceActive Network Node”, In IEEE Network, January/February 1999.[9] E. L. Nygren, S. J. Garland, and M. F. Kaashoek, “PAN: a high-performance active network node supporting multiple mobile code system”, In the Proceedings of the 2nd IEEE Conference on Open Architectures and Network Programming (OpenArch ’99), March 1999. [10] D. L. Tennenhouse, and D. J. Wetherall. “Towards an Active NetworkArchitecture”, In Proceeding of Multimedia Computing and Networking , January 1996.[11] D. J. Wetherall, J. V. Guttag, D. L. Tennenhouse, “ANTS: A toolkit forBuilding and Dynamically Deploying Network Protocols”, Open Architectures and Network Programming, 1998 IEEE , 1998 , Page(s): 117 –129.[12] B. Braden, A. Cerpa, T. Faber, B. Lindell, G. Phillips, and J. Kann.“Introduction to the ASP Execution Environment”: /active-signal/ARP/index.html .[13] “The java language: A white paper,” Tech. Rep., Sun Microsystems,1998.。

3桂电毕设英文翻译原文

毕业设计(论文)英文翻译原文院（系）：成人教育学院专业：工商企业管理学生姓名：周杨学号： 030113300433指导教师：王蕴老师职称：教授2014年10月12 日The Changing Pattern of Pay and BenefitsTudor, Thomas R, Trumble, Robert R Journal of Compensation & Benefits/May/2008Today, many companies still base their reward systems on the 1950s compensation mode l made popular during the brief period when U.S. companies dominated the world. With today s increasingly competitive environment, however, companies must look more closely at the co st-benefit of rewards, instead of just using them in an attempt to reduce employee dissatisfacti on. Companies must provide short-term motivation and encourage employees to develop long -term skills that will aid the company. Most importantly, companies must also attract and retai n high performers, instead of alienating them with pay systems that give everyone pay increas es without regard to levels of performance. For example, such new compensation approaches may include skill-based pay, gainsharing plans, and flexible benefits systems.Traditional compensation approaches are still often modeled on the centralization-based organizational model, in which decisions were made at the top and management rigidly define d tasks. However, with global competition becoming an increasingly prominent issue, compan ies need reward systems that match their movement to decentralized structures. Larger numbe rs of companies are also becoming very aware that they cannot just pass additional compensat ion costs onto future customers. Today, our pay systems must move in step with the participati ve-management trend by becoming more flexible instead of remaining fixed. This adjustment involves many factors including shorter product life cycles, a need to be more flexible, a need for workers to continually gain additional skills, and for them to think more on the job.In today's most successful companies, employee rewards and benefits are increasingly in corporated into an organization's strategic planning. Why? The rationale is that employee com pensation has a substantial impact on the long-term financial position of a firm. Compensation structures should consider an organization's strategic requirements and should match organiza tional goals. Compensation strategic planning should involve:consideration of the internal and external environment; and creation of an organization's compensation statement, compensatio n goals, and the development of compensation policies.Today, one strategic compensation trend is the use of pay incentives instead of the traditi onal, annual “everybody gets” pay increase. The rationale is to control costs and to more close ly tie performance to compensation. We can group the changing pattern of compensation into two general areas: Pay Method Trends and Benefits Trends. Human Resources managers shou ld familiarize themselves with these changing trends and determine the plan that is most suita ble for their organization.PAY METHOD TRENDSThere are a number of pay methods available for use by employers, including general pa y increases, cost-of-living increases, merit pay, bonuses, skill-based pay, competence-based pa y, CEO compensation, gainsharing, and various types of incentive pay.General Pay IncreaseA general pay increase is a pay increase given to everyone in a company. It can be a lum p-sum payment, but it is more likely to be a percentage increase in base salary. The employer' s rationale for the pay increase may have been the result of a market survey, job evaluation, or just a profitable year. The trend, however, is for general increases to decline as pay-for-perfor mance systems become increasingly dominant. In addition, giving everyone the same raise so metimes decreases morale because high-performing employees see poor performers getting th e same reward.Cost-of-Living IncreaseCost-of-living increases are general pay increases triggered by a rise in an inflation-sensi tive index, such as the consumer price index or the producer price index. As with general pay increases, the use of cost-of-living pay increases is decreasing among companies. The rational e for this decrease is that with lower inflation (thus little change in prices), incomes are more s table and the need for inflation adjustments is not as great as it was in the past. In addition, col lective bargaining agreements are now less likely to include provisions for cost-of-living incre ases, so nonunion firms are not under as much pressure to provide them in an attempt to matc h union-negotiated compensation. Their decline can also be attributed to the fact that employe rs are moving away from pay systems that are nonperformance related.Merit PayMerit pay is another generic term in which pay incentives are given for overall job perfor mance.² Some problems frequently encountered with merit pay plans include: the use of subjective criteria when measuring employee performance;a lack of uniform standards for rating individual employees;differences among managers in how to make individual ratings.Merit pay was the first attempt by firms to create a pay-for-performance system. Howeve r, due to employer (and employee) dissatisfaction with merit pay plans, the trend is to eliminat e them and instead use pay-for-performance plans that are more objective (such as bonus plan s), and that use specific performance measuring criteria that aid in the performance appraisal p rocess.³ This trend includes both the private and public sectors, because the merit pay system i n the federal sector has also been inadequate.BonusA bonus is a generic term involving a type of pay-for-performance plan. Managers can give a bonus for individual or group performance, and for meeting objectives such as MBO (ma nagement by objectives). Researchers and practitioners have given these plans high marks for motivating employees, for creating loyalty, and for meeting performance objectives. In additio n, bonuses reduce the turnover of high-performing employees and increase the turnover of lo w performers, who do not get bonuses. If the bonus system is well-designed, they also create i nternal equity. As such, bonus systems (pay-for-performance) are the current trend in compens ation.Skill-Based PaySkill-based pay emphasizes a company's desire to increase the skills and knowledge of it s workforce. It may involve classes, voluntary job rotation, or tests. Its benefits are many, incl uding having trained people available to do a job if someone is absent. Skill-based pay also w orks well with quality circles because:it provides employees with a better understanding of the jobs their coworkers perform;it reduces resistance to restructuring or other needed changes;it leads to a more flexibleworkforce that can better adapt to new technologies or processes; and it encourages a lea rning environment.It does, however, require a large investment in training which can be expen sive.Competence-Based PayCompetence-based pay (the grid system) is very new and does vary from plan-to-plan. T he idea is not only to reward employees for how well they do a job, but for how they do the jo b. For example, a competence-based pay plan can be used to persuade workers to use the com puters that are sitting on their desks, or to adapt to other changes that come along. The rational e behind a competence-based pay plan is to keep employee skills current.CEO CompensationThe compensation of CEOs (and other top executives) has also been changing, and now inclu des more pay incentives—such as stock options—to better link performance with compensati on. Plans linking executive pay with performance may include stock options, cash bonuses, p hantom stock, or deferred compensation, all of which are ways of making top management m ore accountable for company performance. Today, performance considerations are a larger par t of executive compensation. The Securities and Exchange Commission also requires corporat ions to explain the rationale behind their executive compensation programs to shareholders.GainsharingGainsharing is a pay-for-performance plan in which “gains” are shared with employees f or improvements in profitability or productivity.Gainsharing plans are designed to create a partnership with employees so that both management and labor are working toward the same goa ls and that both groups are benefiting from the results. Gainsharing is a growing trend, and it f its well with other trends, such as participatory management, worker empowerment, and team work. It is also being used in many service businesses, such as banking and insurance. Gainsh aring encourages employee involvement and acceptance of change, and aligns employee goals with company goals.Five Types of Pay IncentivesWhile all pay incentives can be generically coined as “gainsharing,” we will briefly ment ion five types:1. ESOPs. Employee Stock Ownership Plans allow the sharing of gains through dividends and any increase in the value of company stock. ESOPs do create ownership in the company for e mployees that may result in additional motivation, but they do not necessarily have a participa tive-management component.2. Profit-Sharing Plans. Profit-sharing plans allow employees to share in the revenue they hel ped generate. This sharing can be either deferred or immediate. Some observers argue that ass ociating rewards and performance is difficult if managers only give rewards annually, and that perhaps employees should not share in the profits because they do not share in the risks. How ever, companies such as Lincoln Electric and Ford feel that profit sharing is a strong inducem ent to increase performance. The current rate of growth of these plans is significant. For best motivational results, companies should use a system that is based on some criteria that emplo yees understand, instead of just an arbitrary amount. The advantage of profitsharing plans is t hat employers do not have to pay a large sum of money if the profit target is not met.3. Scanlon Plans. Scanlon plans allow employees to share in any savings in labor cost (using a ratio) that is due to their increased performance. The rationale for ScanIon plans is to help em ployees identify with and participate in the company. Employees participating in such plans m ay have access to suggestion programs, brainstorming sessions, or committees to solve produc tion problems. The employer and the employees then share in the savings that result.4. Rucker Plans. Rucker plans allow employees to share in any improvement in the ratio of e mployee costs to the valued added in manufacturing. This is the most complex gainsharing pla n, because it deals with four variables: labor costs, sales value of production (changes in equip ment, or work methods, for example), purchases of outside services such as subcontracting, or utilities, and purchases of outside materials, involving “inventory, theft, and so on”. Rucker p lans are designed to give employees a stake in areas such as reducing labor costs, using raw m aterials, and outsourcing decisions. As such, everyone shares in the savings.5. Improshare Pl ans. Improshare plans allow employees to share in productivity gains that occur because of their efforts.[sup5] Following the Improshare approach, managers give bonuses when the actual hours for a specific amount of productivity are less than the standard that they created using a formula. The savings are split between the company and the workers, in a ratio such as 50⁄50.CHANGES IN BENEFIT PLANSChanges in benefit plans have occurred as a result of efforts to keep up with trends, to co ntain costs, and to meet government regulations. Employees often view benefits as an entitle ment, and their cost—which has steadily increased—now averages 36 percent of total wages. The trend is to get the most out of benefits, while keeping costs down. For example, employer s do not want to pay for any overlap of coverage, or to pay too much for coverage. As their co sts continue to go up, employers are now starting to question how much employees value their benefits. For example:Do they support recruitment, motivate, and retain good employees? Do they support the strategic mission of the firm?Do proposed benefits support the company's retention goals and the demographics of pot ential recruits?Do they support the company culture or the culture the company now wants to promote?A movement now exists among employers for measuring benefit results and continuously eval uating benefits. A focus on Total Quality Management makes the internal employee the custo mer of HR departments who have the product of “benefits.” HR departments want to satisfy t he customer, but are also benchmarking and quantifying each benefit. The strategic trend is to design benefits to make it easier to realize the corporate mission and to enhance the value of t he benefits offered. Another major trend is offering flexible benefits where employees make b enefit decisions to fit their lifestyles. 401(k) PlansToday, 401 (k) plans are popular retirement vehicles because contributions are made on b efore-tax basis and investment earnings are tax deferred. They also address the trend of more mobile employees, who do not stay with a company for their entire working lives. With 401 ( k) plans, employee accounts can be transferred to another company's plan or to an Individual Retirement Account. A company can also establish 401(k) plans without providing for employ er matching contributions, so the only employer cost is for plan administration.Managed Care PlansManaged care plans, such as Preferred Provider Organizations (PPOs) and Health Mainte nance Organizations (HMOs), are a growing benefit trend away from traditional medical insur ance. These plans often include preventive maintenance features that attempt to treat illnesses earlier to avoid higher costs. Although they have disadvantages, they are designed to save ben efit expenses. And, due to the of rising cost of health care, companies can no longer afford towrite a blank check to cover their employees' health care costs. So, they are requiring employ ees to pick up a portion of these costs by shifting more of the premium burden to employees, and⁄or increasing deductibles.Prepaid Legal ServicesPrepaid legal services are new plans in which legal expenses are paid before the services are used. The growing number of lawsuits in this country has sparked demand for this type of benefit. A company may offer this benefit if it wants to protect its employees from the threat o f litigation, so that their minds are on their work. Or, it may offer this benefit to keep up with i ts competitors who are offering such plans. At this point, it is too early to tell how popular pre paid legal services plans will be in the future, though it is possible that they will be offered as a flexible benefit option.Dependent-Care AssistanceDependent-care assistance is also a new benefit whose popularity is growing. Companies are beginning to recognize that in todays economy, both parents often work and that many wo rkers are raising children in single-parent households. This benefit can help attract employees and reduce turnover because parents do not like to make changes if their child-care provider s atisfies them. In addition to caring for children, many employees are responsible for the care o f elderly parents or other relatives. Eldercare is a benefit that addresses this need, and allows e mployees to stay focused on work instead of worrying about their parents. Dependent care ass istance is likely to be increasingly offered as an option in flexible benefit plans.Wellness ProgramsWellness programs are designed to reduce sick-leave and medical expenses. These progr ams may include exercise, nutrition, stress reduction classes, as well assmoking and substance abuse help. Why the popularity of wellness and counseling progr ams? Studies show that lifestyle and diet impact illness, and that counseling programs can hel p curtail other higher cost benefit usage.In linking benefits to a corporate strategy plan, employers want to: help employees to lower their health costs; reduce turnover of good employees; and increase productivity .A company's HR department can perform audits to make sure that a wellness program is a valued added benefit.Flexible Benefit PlansFlexible benefit plans are increasing in number because the needs of workers are more di verse today. The rationale behind these plans is to increase employee satisfaction, reduce turn over, and decrease expenses to employers. Flexible benefit plans can also help employees realize the value of their benefits. The cost to administer these plans may be higher than with stan dard benefit provision, but flexible benefit plans can save money by not providing a specific b enefit to an employee who does not want it. Flexible benefit plans support workplace diversit y and changing employee demographics by allowing employers to offer a variety of benefits t o their workers.Frequently included in flexible benefit plans are salary reduction features that enable em ployees to divert pretax dollars into nontaxable benefit choices. If an employer needs to reduc e costs because of low profits one year, it can lessen its contribution to benefits, but still allow employees to direct where they want their benefit dollars to go, instead of making across-the-board cuts in coverage.Flexible benefit plans also put a price on benefits, which helps makes employees aware o f their actual cost—a fact often taken for granted. Flexible benefit plans help to equalize benef its provision because one employee may want a child-care benefit, but an older employee may want more life insurance coverage. These plans tend to have a positive impact on employees and are more cost-effective to employers.Flexible benefit plans also:reduce the entitlement mentality that has become associated •with the provision of many benefits;better associate benefits with direct compensation; andfit well with the trend of more employee involvement in company decision-making.Outplacement Benefit PlansOutplacement benefits plans provide support for terminated employees, and in turn show the remaining employees that the company is trying to be fair. Such plans may include office space, resume writing assistance, and employment counseling, among other benefits. These pl ans are designed to reduce termination litigation and to help maintain the morale of remaining employees.Source:Tudor,Thomas R,Trumble,Robert R.The Changing Pattern of Pay and Benefits[J].Jour nal of Compensation & Benefits,2008,(May):22-25Pay for performanceNot everyone sees the trend toward paying for skills and/or competencies as a good thing:It would be easy to conclude from reports in the business press that merit pay is dead and organizations need to reconstitute pay plans to pay people in some new way. Suggestions include paying employees for the knowledge, shills, abilities and behaviors they bring to theworkplace. Although interesting, this call for wholesale reform overlooks fundamental tenets of economic and behavioral theories.Pay for performance is the holy grail of modern compensation administration—widely sought but hard to actually achieve .Pay for performance is the flag, motherhood, and apple pie, but it is easier said than done. One primary problem is defining performance properly, so that the organization pays for results and not for effort. Once over that hurdle, there remains the large impediment of finding enough money to make the reward for top performance meaningful. Many different approaches are used—various variable pay schemes, annual awards in lieu of permanent increase in base pay, and the traditional merit pay salary increase.The concept of pay for performance has different meanings to different people. Many either fail to recognize the pay for performance fails when the different in reward between adequate performance and outstanding performance is inconsequential or cannot solve the problem of funding adequate differentiation while dealing with essential range maintenance costs.For example, Logue reported on the introduction of performance-based pay for unionized employees in a public university. The old system had four annual, essentially “automatic,”5percent steps from minimum to maximum. The new system added 10 percent to the top of the salary range. All employees would move through the regular range automatically, but growth within the top 10 percent was based only on performance. Since 20 percent of all salary increase funds were allocated to performance increases, top performers could receive additional amounts over and above the automatic movement through the standard portion of the salary range.Such performance-based salary increases (PSIs) went to 12 percent of the represented employees, who receive PSIs ranging from 3.9 to 5.9 percent in the first fiscal year (2000 to 2001). PSIs ranged from 0.5 to 4 percent in fiscal year 2001 to 2002 due to the greater number of employees receiving increases. One wonders what happened the third year! In any event, achieving an extra 1 or 2 or 3 percent is unlikely to stimulate anyone to significantly higher levels or performance, particularly when they are guaranteed automatic annual increases.Others take steps to address the differentiation problem:Through the implementation of a new tool called the Monoline Merit Increase Matrix, one organization shows how it rewards employees based on performance and gets more mileage out of its merit increase budget…The Monoline Merit eliminates the use of comparisons for merit increase. It is designed to create a larger distinction in the merit percent provided between top performers and employees who meet expectations and are paid fairly for their work…Under the new methodology, managers must examine the possibility that employees who meet performance goals do not have to receive a merit increase if they are competitively paid. Pay for whose performance :Even if one can solve the differentiation problem, there still remains the problem of determining the locus of performance pay plans all devolve into two broad categories, depending on whether performance is measured at the group or at the individual level: Group plans can fail to specifically direct or reward individual employees behaviors. As a result, group plans have produced somewhat limited results with respect to improvements in employees performance or organizational profitability. Further, group plans do not different reward individual who perform well vs. those who do not. This may exact the perception of pay inequities among better performers.Performance pay plans based on individual performance are more effectives in improving individual employee performances vs. group plans. Typically, these plans provide specific and objective goals for employees to work toward. However, rewarding individual performance may reduce cooperation among employees and focus employees on a restricted range of results.Designing an effective compensation program:First, an effective compensation program should recognize that monetary rewards do change employee behavior despite what some academicians have claimed. The power of money is twofold. It not only is valued for itself, for what it can buy, but it can also serve as a powerful communication devise, as a score card if you will.Second, stick to the basics when designing a salary program. Pay people at a reasonable market level for base salary based on survey data (what is reasonable will depend on your ability to pay and the availability of the talent you need.) focus primarily on external pay market data, and maintain internal equity only within each separate pay market. That is, internal equity is important within information technology, engineering, accounting, etc., but is not important between these groups as they are in separate pay markets. One size never fits all!Third, use variable pay everywhere. For those positions that cannot be individually measured, use group measures (work group, location, division, and/or corporate measures, as appropriate). For those positions that can be individual measured, use a combination of individual and group measures (individual measures to motivate individual effort, group measures to encourage cooperative behavior).Fourth, keep the performance measures as simple as possible and limit their numbers, preferably to two or three, Remember, what you measure is what you get, so pick yourmeasures carefully.Fifth, communicate, communicate, communicate. Communicate the details of the program. Communicate the rationale for the measures—that is, how they fit into the organization’s strategy. Communicate on an ongoing basis actual performance versus target performance.Source: Martin G.Wolf,2002 “linking performance scorecards to profit performance pay”ACA News,vol.41,no.4,april,pp.23-25.Variable payVariable pay is an expanding field within compensation driven by the emerging trends of pay for performance and competitive advantage. Funding these new programs and developing the processes supporting long-term effectiveness is critical.Pay for performanceIn the past, company employment was routinely assumed to be for a career. Many, many employees worked for one organization for their entire work life. Loyalty on the part of the employer and employees was taken for granted. Times have changed. Reengineering, downsizing, and talent wars have reworked the playing field for employment decisions. No longer does a new college graduate dream of working for the same company for life. In addition, worldwide competitive business pressure has focused corporations on performance. In the past and still for many organizations today, paying for performance is normally done with promotions over the career. Base pay increase over time is a normal method to reward performance.Information technology professionals can now move from company to company with ease and can expect to receive a year 2000 bonus if they stay until the new millennium. Organizations realize the competitive demands for change and the need to motivate change. Many employees are now asking “What is in it for me if I take the risk?” Variable pay is an excellent way to answer the question. Pay for performance with variable pay below the executive level is in its infancy for most organization excluding the sales organization. Less than 30 percent is profit sharing and does not have a line of sight to business unit performance .Fewer than 10 percent of organization have variable pay programs for all employees that reward individual, team, and business unite performance. Variable pay has many opportunities for growth with the new organization emphasis on performance, retention, and competitive advantage.Funding variable payFinancially, variable pay is very attractive compared to base pay increase programs. Base pay increase compound and a concern for permanent increase cost. In addition, base pay increases have an entitlement mentality where the recipient is looking for the next one shortly after receiving the last increase. Many corporation reinforce this expectation by having an annual increase plan (normally called a merit increase plan ) to adjust for inflation and market movement.Variable pay is attractive because it does not compound from year to year, and the unspent funds can be reused each year or budget cycle. Having employees learn their performance bonus each year creates a compelling reason for them to improve instead of relaxing into an entitlement mentality, which is often the result of base pay increase programs. When business results are good, the payout can be attractive, and, when times are bad, the payout is small, reducing costs and helping to improve the bottom line.Strategic planning can support the movement to variable pay. Moving to a strong variable pay program can take years with the need to build success along the way.Variable pay successSo if variable pay has such great potential, why has there been such a reluctant to implement variable pay? One answer is that the failure rate for variable pay plans is 38 percent as document in an ACA study by Marc Wallace. The success rate in executive compensation and sales compensation is substantially greater, but the concern for excessive reward is real. Executive compensation requires hand holding and considerable administration. Many small-group plans require period redesign, which takes more compensation consulting resources than are available. These draw backs are part of the reluctance of management to implement variable pay.Building variable pay plans to be continuous for the long term is the key to variable pay success, Most plans need to be renewed annually to ensure on going success. Fairness, trust and impact on the business are all measures of success. Plans that do not continuously evolve need extra attention every year and will fail to more frequently. I helped implement two variable pay plan for all employees at Coring incorporated, and those plans are now over 10 years old and going strong, One is a spot bonus plan, and the other is good sharing .variable pay plans can indeed work very well.Balancing individual incentives with shared business goals is important. This rewards for business success are the most critical and should be more significant in total dollars than individual reward. The bottom line is that the business needs to succeed. Line of sight and control are also important variables. Many times this is where incentives come into play. People like to be judged on what is control is delicate. Too much emphasis on individual。

采矿工程毕业设计_外文翻译英译汉中英文

ROOM-AND-PILLAR METHOD OF OPEN-STOPE MINING空场采矿法中的房柱采矿法Chapter 1.A Classification of the Room-and-Pillar Method of Open-Stope Mining第一部分，空场采矿的房柱法的分类OPEN STOPING空场采矿法An open stope is an underground cavity from which the initial ore has been mined. Caving of the opening is prevented (at least temporarily) by support from the unmined ore or waste left in the stope,in the form of pillars,and the stope walls (also called ribs or abutments). In addition to this primary may also be required using rockbolts , reinforcing rods, split pipes ,or shotcrete to stabilize the rock surface immediately adjacent to the opening. The secondary reinforcement procedure does not preclude the method classified as open stoping.露天采场台阶是开采了地下矿石后形成的地下洞室。

通过块矿或采场的支柱和（也称为肋或肩）采场墙形式的废料的支持来（至少是暂时的）预防放顶煤的开幕。

除了这个，可能还需要使用锚杆，钢筋棒，分流管，或喷浆，以稳定紧邻开幕的岩石表面。

翻译原文

The inﬂuence of temperature on nutrient treatmentefﬁciency in stormwater bioﬁlter systemsG.-T.Blecken*,Y.Zinger***,T.M.Muthanna**,A.Deletic***,T.D.Fletcher***and M.Viklander* *Urban Water,Department of Civil,Mining and Environmental Engineering,Lulea˚University of Technology, 97187Lulea˚,Sweden(E-mail:godecke.blecken@ltu.se;maria.viklander@ltu.se)**Norwegian Institute for Water Research,Havnegata9,7010Trondheim,Norway(E-mail:tone.muthanna@niva.no)***Department of Civil Engineering,Facility for Advancing Water Bioﬁltration,Monash University,Victoria 3800,Australia(E-mail:yaron.zinger@.au;Tim.Fletcher@.au;ana.deletic@.au)Abstract Nutrients can cause eutrophication of natural water bodies.Thus,urban stormwater which is an important nutrient source in urbanised areas has to be treated in order to reduce its nutrient loads.Bioﬁlters which use soilﬁlter media,bioﬁlms and plants,are a good treatment option for nutrients.This paper presents the results of a bioﬁlter column study in cold temperatures(þ28C,þ88C,control atþ208C) which may cause special problems regarding bioﬁlter performance.It was shown that particle-bound pollutants as TSS and a high fraction of phosphorus were reduced well without being negatively inﬂuenced by cold temperatures.Nitrogen,however,was not reduced;especially NO x was produced in the columns. This behaviour can be explained with both insufﬁcient denitriﬁcation and high leaching from the columns. Keywords Bioﬁlter;cold climate;nutrients;stormwater treatmentIntroductionNutrients can cause eutrophication in receiving natural water bodies(Browman et al., 1979;Pitt et al.,1999;Kim et al.,2003).Stormwater runoff is an important source of nutrients in urbanised areas(Larm,2000;Graves et al.,2004;Taylor et al.,2005),and it should therefore be treated.Stormwater bioﬁltration,also known as bioretention,is a novel option that might be able to treat nutrients in stormwater in order to prevent eutrophication of recipients.A bioﬁlter consists ofﬁlter media placed in a trench or basin that is planted on the top.It has a detention storage on the top(by placement in a depression)and a drainage pipe at the bottom to collect the treated water.Stormwater is treated by mechanical,biological and chemical processes in theﬁlter media,but also by the plants and bioﬁlms,that develops in the media and on the plant roots(Prince George’s County,2002;Hsieh and Davis,2005).Several studies conducted so far have shown a signiﬁcant removal of phosphorus, phosphate and ammonium,but with low(and sometimes negative)removal of nitrate (Davis et al.,2001;Lloyd et al.,2001;Henderson et al.,2007).However,bioﬁlters are still a relatively new technology and hence,only limited data of the performance of these systems are available.Particular problems could arise when implementing bioﬁlters in regions with constant or temporary cold temperatures,due to reduced biological activity, shorter growing seasons and a smaller number of adapted plant species.However,these systems may still perform well in these instances,since adequate nutrient removal has been achieved in constructed wetlands in cold subalpine climates(Heyvaert et al.,2006). Bioﬁlter performance in cold temperatures is the deciding factor to their successful implementation in regions with rainfall on non-frozen ground during cold periods Water Science & Technology Vol 56 No 10 pp 83–91 Q IWA Publishing 2007 83doi:10.2166/wst.2007.749(autumn,winter and spring in temperate climate;autumn,later spring and summer in cold climate).This paper presents preliminary results of a study of the performance of bioﬁlters in relation to temperature.The aim was to determine the nutrient treatment performance of stormwater bioﬁlters in low temperatures in order to enable an analysis of whether there is a correlation between temperature and treatment rate.Material and methods Experimental set-up Laboratory tests were conducted on 15bioﬁlter mesocosms (‘bioﬁlter columns’)made of PVC stormwater pipe (inner diameter:377mm,area:0.11m 2,height:900mm).A trans-parent top (height:400mm)allowed water to pond without affecting light availability for plant growth.The inside wall was sandblasted to prevent preferential ﬂow along the wall.A drainage pipe (diameter:58mm)at the bottom discharged to a sampling outlet (Figures 1and 2).The ﬁlter media in the columns included four layers (listed from top,Figure 2):(1)sandy loam layer,400mm,medium to coarse sand with 20%topsoil in the upper 100mm,(2)sand layer,400mm,ﬁne to medium sand,(3)transition layer,30mm,coarse sand and (4)underdrain,70mm,ﬁne gravel with embedded drainage pipe.The columns were planted with Carex rostrata Stokes (Bottle sedge)which is wide-spread in the northern hemisphere (Anderberg and Anderberg,2006).The plant density in the columns was 8plants per column,which corresponds to a density of approximately 73plants/m 2.Before they were planted in the columns,the plants were grown for 5weeks outside to develop a substantial root system.Afterwards they were grown in the columns for two month and irrigated with tapwater.Figure 1Bioﬁlter columns in climate roomG.-T.Bleckenetal.84In order to investigate the temperature effect on the bioﬁlter performance,the tests were carried out in three thermostat controlled climate rooms at constant target tempera-tures of þ28C,þ88C,and þ208C (þ35.68F,þ46.48F,and þ688F,resp.).Five columns each were placed in every climate room (Figure 1).The air temperature in the climate rooms was logged at a 15minute interval using one EBI 20-T (88C)and two EBI 2T-112(28C and 208C)temperature loggers (ebro Electronic,Ingolstadt,Germany).All columns were illuminated with high pressure sodium greenhouse lamps (G-Power Agro,400W,55,000Lm)12hours daily.Experimental procedureStormwater .Since natural stormwater was not available in the required quantity and with constant water quality over the time of the experiment,nor could be stored without signiﬁcant changes to its quality,semi-synthetic stormwater was used.It was made by mixing tap water with gully pot sediment to achieve the required TSS concentration,topped with certain pollutants to achieve the targeted pollutant concentrations,as outlined in Table 1(only for nutrients;heavy metals were added as well,but are not reported in this paper).A new mixture was made for every stormwater application.The water was stored at the respective temperature (28C,88C,208C,resp.)for at least 24hours before dosing the columns in order to have similar water and air temperatures.In Lulea ˚(Sweden)it rains approximately two times per week in September and October (the month with the most rain events in cold temperatures)with a total precipi-tation amount of around 110mm (SMHI,2005).This corresponds to an average of 5.4L/m 2stormwater runoff per rain event from a catchment with 85%impervious surface.It Figure 2Bioﬁlter column conﬁgurationG.-T.Blecken et al.85was assumed that the bioﬁlter area represents appr.4%of the catchment area (one col-umn with 0.11m 2for 2.75m 2catchment)(Wong et al.,2006).Therefore every column was dosed with 15L (5.4L/m 2·2.75m 2¼14.85L <15L)of stormwater twice weekly.Sampling .From the stormwater a sample was taken in three replicates before every stormwater application.All outﬂow water was collected in PE-tanks until the next dosing event,it was stored at þ28C,and a composite sample was taken from each PE-tank,i.e.15samples per each dosing.This paper reports on results of the ﬁrst four weeks of stormwater dosing (i.e.eight events).Analyses .All samples were analysed for total and dissolved N,ammonium (NH þ4),nitrate/nitrite (NO x ),TSS,and pH.The dissolved samples were ﬁltered,using Whatman ME25membrane 0.45m m pore size ﬁlters.Before analysing P and N,the samples were digested with peroxo-disulphate (according to the Swedish standard method SS 028127)and oxidised with peroxisulphate (SS 028131),resp.The analyses were conducted with a continuous micro ﬂow analyser (QuAAtro,Bran þLuebbe,Hamburg,Germany)according to the device-speciﬁc methods no.Q-031-04for P,no.Q-003-04for N and NO x and no.Q-001-04for NH þ4.TSS was determined by ﬁltration through Whatman GF/A 1.6m m pore size glass microﬁbre ﬁlters (SS-EN 872)in one replicate.pH was measured with a ﬁeld pH-meter (pH330,WTW GmbH,Weilheim,Germany).Data analyses Pollutant reduction was calculated as reduction ¼(1-(out/in))·100%.Thus,production of pollutants results in a negative reduction rate.Analysis of variance (ANOVA)was used to test the inﬂuence of temperature on outﬂow concentrations.Furthermore,box plots were created for nitrogen species and phosphorus to compare in-and outﬂow concen-trations and their evolution over time.All statistical calculations and plots were computed with the software MINITAB w 15.1.Results and discussion The mean temperature in the three different rooms were 1.88C (SD:1.018C),7.48C (SD:0.358C)and 20.38C (SD:1.028C)respectively.Thus,the real temperatures were very near the target temperatures.The mean inﬂow and outﬂow pollutant concen-trations (mg/L)as well as reduction rates (%)at the three different temperatures are shown in Table 2.pH .The average pH-value of the stormwater was 6.9.The pH increased in the columns and the outﬂow pH at all temperatures was around 7.4.Table 1Semi-synthetic stormwater pollutants and their sourcesPollutant Targeted SourcepH6.9H 2SO 4TSS140mg/L Stormwater gully pot sediment (#400m m Phosphorus (total)0.3mg/L KH 2PO 4(potassium dihydrogen phosphate)0.32mg/L nitrate:KNO 3(potassium nitrate)Nitrogen (total) 1.4mg/L 0.24mg/L ammonium:NH 4Cl (ammonium chloride)organic nitrate:C 6H 4NO 2(nicotinic acid)G.-T.Bleckenetal.86TSS .Reduction of TSS was around 97%,and whilst the effect of temperature on this removal was statistically signiﬁcant (p ¼0.001),it accounted for very little of the observed variation,and was of no practical signiﬁcance (Table 3,Figure 3).Other factors are clearly inﬂuencing TSS removal,although it was high in all cases.The low difference between the columns at different temperatures is not surprising since the TSS removal is mainly a matter of mechanical ﬁltration which itself is not inﬂuenced by temperature (unless the soil media soil freezes forming channels).Because of the high TSS removal,a high (and largely temperature independent)removal of particle bound pollutants could be expected.Phosphorus .In the stormwater inﬂow 85%of the total phosphorus was particle bound.The fraction was slightly different in the outﬂow at the different temperatures (28C:87%particle bound,88C:84%particle bound and 208C:82%particle bound).A temperature independent removal of about 80%was detected for total phosphorus (p ¼0.933,Table 3).There is a very clear decrease in the outﬂow concentrations and their variances over time (Figure 4).Dissolved phosphorus was also well removed by the bioﬁlter,with no signiﬁcant temperature dependence (p ¼0.285,Table 3).However,its reduction rate was slightly higher at cold temperatures.The results make sense,if we assume that physical ﬁltration is the main mechanism for P removal,while biological activity within the soil may cause some leaching of P from media (the higher biological activity occurs at higher temperatures).This leaching is getting smaller with time as the Table 2Pollutant concentrations and removalStormwater (2)all temp.Outﬂow (3)28C 88C 208CpH 6.90(0.20)7.32(0.13)7.40(0.10)7.46(0.18)TSS concentration 142.7(13.9) 3.6(1.4) 5.1(1.7) 4.6(2.1)mean reduction 97.5%96.4%96.8%N total concentration 1.38(0.16) 1.38(0.29) 1.54(0.25) 4.23(0.68)mean reduction 20.5%211.6%2207.8%N dissolved concentration 1.16(0.08) 1.33(0.26) 1.31(0.15) 3.94(1.02)mean reduction 214.9%213.2%2240%NO x (1)concentration 0.24(0.01)0.72(0.26)0.89(0.13) 3.79(0.57)mean reduction 2198%2265%21461%NH 4(1)concentration 0.32(0.05)0.11(0.05)0.14(0.06)0.15(0.05)mean reduction 64.5%56.2%51.7%P total concentration 0.292(0.018)0.055(0.036)0.058(0.032)0.056(0.030)mean reduction 81.2%80.3%80.7%P dissolved concentration 0.031(0.017)0.007(0.002)0.009(0.004)0.010(0.005)mean reduction 77.5%71.5%69.3%(1)only the ﬁrst 4events have been analysed (2)three replicates per event analysed (3)mean value of ﬁve replicate columns and all events.Table 3One-way ANOVA:p-value of temperature inﬂuence on outﬂow concentrations and R 2(adjusted)of the modelp -value R 2(adj.)TSS 0.0019.0%N total 0.00089.4%N dissolved 0.00080.4%NO x (2)0.00093.7%NH ð2Þ40.065 6.0%P total0.9330.0%P ð2Þdiss :0.285 2.1%G.-T.Blecken et al.87source is depleted,which explains the decreasing outﬂow concentrations with time in Figure 4.Overall however,mechanical removal of phosphorus is the most important factor and therefore overall P removal is high.Nitrogen .While the bioﬁlters at 28C and 88C showed little or no leaching of total nitrogen,a high production (on average 2208%removal)was observed at 208C (Figure 5,Table 2).No trend over time wasobserved.Figure 3Box plot of in-and outﬂow TSS concentrations at the 3different temperatures and 8samplings Figure 4Box plots of in-and outﬂow total phosphorus concentrations at the 3different temperatures and 8samplingsG.-T.Bleckenetal.88The total nitrogen in the synthetic stormwater inﬂuent was 84%dissolved,whilst in the treated outﬂow water 96%,85%and 93%was at 28C,88C and 208C,respectively.The proportion of the nitrogen compounds changed during the treatment in the bioﬁlter.NH þ4was reduced at all temperatures,whilst NO x was produced (Table 2,Figure 6).This means that nitriﬁcation in the unsaturated zone of the bioﬁlter was occurring and there-fore NH þ4levels were decreased and NO x levels were increased.Since no denitriﬁcation was taking place due to the lack of an anoxic zone and/or a carbon source,levels of NO xFigure 5Box plots of in-and outﬂow total nitrogen concentrations at the 3different temperatures and 8samplingsFigure 6Box plots of in-and outﬂow:(a)dissolved NO x ,(b)and dissolved NH þ4concentrations at the 3different temperatures and 8samplings G.-T.Blecken et al.89However,a signiﬁcant temperature effect was demonstrated for dissolved nitrogen behaviour (p ¼0.000dissolved N and NO x ,Table 3):the higher the temperature the higher the NO 3production due to increasing nitriﬁcation with increasing temperatures.More importantly,more nitrogen from the soil leached to the outﬂow water at higher temperatures.Unfortunately,it is not clear yet whether the leaching will stop over time as plants mature,as has been observed in similar bioﬁlter studies (Zinger et al.,2007).The plants had only 2–3months of establishment,while in Zinger at al ’s experiments they had 5months to establish.It is known that plants (and in particular their roots)play a major role in N removal,since unvegetated bioﬁlters are always demonstrated to leach nitrogen (Hatt et al.,2006;Lee and Schloz,2007),whilst vegetated bioﬁlters do not (Henderson et al.,2007).Conclusion Even in cold climates,it is clear that effective removal of particle-bound pollutants (TSS and particulate phosphorus)can be achieved.This veriﬁes the ﬁndings of other cold climate studies (Ba ¨ckstro ¨m,2002;Muthanna et al.,2007).However,the results showed poor overall removal of nitrogen from the stormwater.In particular,there was a very high production of NO x ,which was probably caused by nitriﬁcation,and limited denitriﬁ-cation.Such large net production of nitrogen was not expected as other studies have shown a reduction or at least only minor production of nitrogen even in bioﬁlters without an anoxic zone (Kim et al.,2003;Scholz,2004;Zinger et al.,2007).However,it is possible that the short establishment time of the plants in the presented experiments is the main cause of this.Further research should be conducted to investigate if the removal of N will begin to improve over time.The bioﬁlters showed the best performance for nitrogen (i.e.the lowest production)at the coldest temperatures.A key area of subsequent research is therefore to determine if the addition of an anoxic zone with added carbon source,which has been shown to improve denitriﬁcation in bioﬁlters (Kim et al.,2003;Zinger et al.,2007),would remain effective,even in cold temperatures.References Anderberg,A.-L.and Anderberg,A.(2006).Den virtuella ﬂoran:Naturhistoriska Riksmuseet.http://linnaeus.nrm.se/ﬂora/(accessed 08October 2007).Browman,M.G.,Harris,R.F.,Ryden,J.C.and Syers,J.K.(1979).Phosphorus loading from urban stormwater runoff as a factor in lake eutrophication -Theoretical considerations and qualitative aspects.J.Environ.Qual.,8(4),561–566.Ba ¨ckstro ¨m,M.(2002).Grassed Swales for Urban Drainage .Doctoral Thesis 2002:06,Division of Sanitary Engineering,Lulea ˚University of Technology,Lulea ˚,Sweden.Davis,A.P.,Shokouhian,M.,Sharma,H.and Minami,C.(2001).Laboratory study of biological retention for urban stormwater management .Water Environ.Res.,73(1),5–14.Graves,G.A.,Wan,Y.and Fike,D.L.(2004).Water quality characteristics of storm water from major land uses in south Florida .J.Am.Water Resour.Assoc.,40(6),1405–1418.Hatt,B.E.,Siriwardene,N.,Deletic,A.and Fletcher,T.D.(2006).Filter media for stormwater treatment and recycling:the inﬂuence of hydraulic properties of ﬂow on pollutant removal .Water Sci.Technol.,54(6–7),263–271.Henderson,C.,Greenway,M.and Phillips,I.(2007).Removal of dissolved nitrogen,phosphorus and carbon from stormwater by bioﬁltration mesocosms .Water Sci.Technol.,55(4),183–191.Heyvaert,A.C.,Reuter,J.E.and Goldman,C.R.(2006).Subalpine,cold climate,stormwater treatment with a constructed surface ﬂow wetland .J.Am.Water Resour.Assoc.,42(1),45–54.Hsieh,C.-H.and Davis,A.P.(2005).Multiple-event study of bioretention for treatment of urban storm water runoff.Water Sci.Technol.,51(3–4),177–181.G.-T.Blecken et al.90Kim,H.,Seagren,E.A.and Davis,A.P.(2003).Engineered bioretention for removal of nitrate from stormwater runoff.Water Environ.Res.,75(4),355–367.Larm,T.(2000).Stormwater quantity and quality in a multiple pond-wetland system:Flemingsbergsviken case study.Ecol.Eng.,15(1–2),57.Lee,B.-H.and Scholz,M.(2007).What is the role of Phragmites australis in experimental constructed wetlandﬁlters treating urban runoff?Ecol.Eng.,29(1),87–95.Lloyd,S.,Fletcher,T.D.,Wong,T.H.F.and Wootton,R.M.(2001).Assessment of pollutant removalperformance in a bio-ﬁltration system-preliminary results.Paper presented at the Second South Paciﬁc Stormwater Conference,New Zealand.Muthanna,T.M.,Viklander,M.,Blecken,G.-T.and Thorolfsson,S.T.(2007).Snowmelt pollutant removal in bioretention areas.Water Res.,41(18),4061–4072.Pitt,R.,Clark,S.and Field,R.(1999).Groundwater contamination potential from stormwater inﬁltration practices.Urban Water,1(3),217.Prince George’s County(2002).Bioretention Manual.Lead Author:D.A.Winogradoff.Department of Environmental Resources,Programs&Planning Division,Prince George’s County,Maryland,USA. Scholz,M.(2004).Treatment of gully pot efﬂuent containing nickel and copper with constructed wetlands ina cold climate.J.Chem.Technol.Biotechnol.,79,153–162.SMHI.Swedish Meteorological and Hydrological Institute(2005).Klimatkarta Uppma¨tt nederbo¨rd 1961–1990,ma˚nadsvis.(In Swedish).Taylor,G.D.,Fletcher,T.D.,Wong,T.H.F.,Breen,P.F.and Duncan,H.P.(2005).Nitrogen composition in urban runoff–implications for stormwater management.Water Res.,39(10),1982.Wong,T.H.F.,Fletcher,T.D.,Duncan,H.P.and Jenkins,G.A.(2006).Modelling urban stormwater treatment–A uniﬁed approach.Ecol.Eng.,27(1),58.Zinger,Y.,Fletcher,T.D.,Deletic,A.,Bleckenr,G.-T.and Viklande,M.(2007).Optimisation of the Nitrogen Retention Capacity of Stormwater Bioﬁltration Systems.Paper presented at the NOVATECH 2007,Lyon,France.G.-T. Blecken et al.91。

毕业设计英文翻译原文

英文原文1. General description of the SIEMAG disc brake unitThis brake unit is the electro-hydraulic control system of a gearless disc brake for winders. The brake unit operates on the exhaust principle, i.e. the braking force is generated by sets of disc springs and released by hydraulic pressure.The braking force generators with the brake shoes directly act axially on the brake disc. The braking force is generated by sets of disc springs and transmitted onto the brake shoes. The number of brake elements determines the respective braking force required.As soon as the brakes are being released, the brake shoes are lifted form the brake disc with the aid of pressure oil. During the braking, the oil flows back into the tank and the brake shoes are being pressed against the brake disc.The braking force generators type BSFG 408 are s series product supplied by the Swedish firm ASEA-Hagglunds. They have a maximum press-down force of2X7906 kN.For reasons of better system availability, the hydraulic pressure is generated by two regulating pumps that are each driven by an electric motor. Both pumps are started when the system is being switched on. Any failure of a pump will be signaled.The oil filtration is undertaken by a pressure filter‘6.2’provided in front of the braking force generators. Furthermore, two gear pumps that are directly coupled with the regulating pumps, maintain a permanent oil cooling and filtering circuit during system operation (filter‘6.1’and cooler ‘14’). Both filters have an electrical contamination control. The mesh size of the filters is specified by the supplier to be 10μm (see TAS No.3.9.6.4). The equipment includes a controlled electrical tank heating. The fluid level in the tank is monitored as well.The service braking is done with the aid of two electrically controlled proportional pressure relief valves‘43.1’and‘43.2’that are hydraulically connected in series.The safety braking is done with the aid of position-controlled 4/2-way electro valves‘53.1’、‘53.2’、‘39.1’、‘39.2’、‘58.1’、‘58.2’、‘66.1’，and‘66.2’which are electrically actuated in closed-circuit connection.In the event of a safety braking, the directional control valves‘39.1’and‘39.2’are switched off, separating thus the pump pressure from the remaining brake releasing system(hydraulic shunt).During the safety braking, the directional control valves‘6.1’and‘66.2’are acting as pilot valves for the 2/2-way valves‘65.1’and ‘65.2’which again release the pressure relief valves‘64.1’and‘64.2’.The electro valves‘53.1’and‘53.2’operate as outlet valves according to TAS No.3.9.5.9.The mechanically controlled pressure relief valves‘60.1’and‘60.2’are arranged in the outlet line of these valves. They determine the residual pressures in the course of safety braking. These residual pressures (pressure stages 1 and 2) are maintained by bladder-type accumulators.The gas pressure of the respective accumulator used is monitored.The march of pressure is adjusted with the aid of mechanical skids which are adapted to the braking process desired.A hand-operated pump‘48’is provided for assembly purposes, when the controlled main stop cocks‘46.1’and‘46.2’in the outlet line of the brake elements are locked.The position-controlled 4/2-way valves‘63’and the pressure relief valves ‘25.1’and‘25.2’(residual pressure accumulator) are fed by a back-up power supply in open-circuit connection. The valves get open when the solenoids are energized.With the command‘RELEASE BRAKE’，the two residual pressure accumulators are filled through the check valves‘87.1’and‘87.2’.The residual pressure accumulator‘24.1’(pressure stage 1) is connected through the 4/2-way valve‘86’. The residual pressure accumulator‘24.2’(pressure stage 2) is automatically connected by a change-over of the 4/2-way valve‘86’, when the hoisting load changes accordingly.2. Functional description of the electro-hydraulic control system corresponding to the hydraulic drawing No.0905216/12.1 Method of operation of the brake unitThe braking force is the sum of pressing forces per brake shoe, reduced by the forces being generated by the oil pressure in the cylinders of the brake element.The force required for the service braking is achieved by controlling the oil pressure. Two pressure regulating valves‘43.1’and‘43.2’, each being fitted with separate control electronics and function control, are connected in series, permitting thus a stepless adjustment of the valves between a minimum and a maximum pressure. In the case of failure of one brake is applied when the spring forces press the brake shoes against the brake disc without counterpressure. The brake is released when the pressure oil in the cylinders of the brake elements reduces the spring forces to zero and the brake shoes are lifted the brake disc.The brake releasing pressure is generated through the pressure-controlled pumps‘1.1’and‘1.2’which are driven by electric motors‘3.1’and‘3.2’. The pressure regulating valves of the pumps are adjusted in such a way that, as soon as the brake releasing pressure has been reached, the pumps reduce the flow rate from the maximum value to the quantity required for maintaining the releasing the pressure. This means in other words that the pumps only deliver the quantity of oil that is demanded to replace any oil losses from leakage and to maintain the pressure adjusted on the pressure regulating valves‘43.1’and‘43.2’.When starting the safety braking, the circuit of the electro-hydraulic brake control system (including pump motors) is cut off. The 4/2-way valves ‘53.1’，‘53.2’,‘39.1’and‘39.2’are thus de-energized and the pump circuit is separated form the brake elements and the pressure accumulators‘24’. The service brake valves‘43.1’and‘43.2’remain energized through a back-up current supply. The residual pressure is as high as to ensure the winder retardation being below the rope slip limit.The hand-operated pump‘48’is only connected for the start-up operation and stored separately.2.2 Operating states2.2.1 Starting the systemThe winder is at standstill and the brake applied. The control voltage and the voltage for the pump motors‘3.1’and‘3.2’is available. The electrical monitoring system signals the system to be trouble-free and all preconditions for starting the pumps‘1.1’and‘1.2’fulfilled (please see also item 2.3.1), which means that the safety circuit is closed as well.The 4/2-way valves‘39.1’and‘39.2’are energized by starting the pump motors‘3.1’and‘3.2’,thus opening the cross section between pumps and brake elements. The safety brake valves ‘53.1’、‘53.2’、‘58.1’、‘58.2’、‘66.1’and‘66.2’close.The pumps‘1.1’and‘1.2’are now connected through the pressure regulating valves‘43.1’and‘43.2’with the brake elements. The coils of these valves are de-energized, i.e. the valves are open, permitting the oil to return without pressure form the pumps‘1.1’and‘1.2’through the pressure regulating valves into the tank.2.2.2 Releasing the service brakeWith the command‘RELEASE BRAKE’, the coils of the pressure regulating valves‘43.1’and‘43.2’are fed with the maximum valve of regulable current, and the valves retain the maximum releasing pressure adjusted. The pumps‘1.1’and‘1.2’thus feed the oil through the valves‘39.1’and‘39.2’to the brake element. The accumulators for the residual pressure‘24.1’and‘24.2’are also filled through the operating pumps. The brake elements are released as soon as the maximum releasing pressure has been reached. The pressure-controlled pumps then reduce the flow rate to the quantity required for compensating all oil loses form leakage. The releasing pressure is maintained by the pressure regulating valves‘43.1’and‘43.2’.The pressure switches‘34.1’/‘34.2’monitor the filling of the bladder-type accumulators for residual pressure‘24.1’/‘24.2’.With this operating state, the valves‘53.1’and‘53.2’are closed and the outlets of the hydraulic safety circuit thus locked.2.2.3 Service brakingDuring the service braking, the pressure regulating valves‘43.1’and‘43.2’are steplessly controlled. This reduces the releasing pressure in conformity with the position of the brake lever. The oil displaced form the brake elements as well as the excess oil form the pumps‘1.1’and‘1.2’flows back through the pressure regulating valves‘43.1’and‘43.2’into the tank.These proportional pressure regulating valves comprise a pilot control valve and a main valve. They are operated by parallel control of the pilot control valves with the main valves connected in series.This means in other words that both proportional pressure regulating valves are always active in the pilot control circuit. However, the main pressure regulating function is always fulfilled by that valve which is nearer to the pressure source. Only in the event of a failure this function is performed by the subsequent valve.The power supply to the control electronics of each regulating valve is additionally backed up by a battery ensuring, in the event of a total power failure or wire brakeage, that at least one regulating valve remains operative.The buffered voltage supplies are monitored for a failure of the buffering in the electrical and electronical circuits of the brake control system.2.2.4 Safety brakingAs soon as the safety circuit is actuated, the pump motors‘3.1’and‘3.2’and the entire electrical control system, except the control of the service brake regulating valves, are de-energized.The oil draining pressure is released through the pressure relief valves ‘64.1’and‘64.2’by de-energizing the solenoid valves‘66.1’and‘66.2’. The releasing pressure in the brake elementsand in the conduits is thus rapidly reduced to that value at which the brake shoes touch the brake discs without pressing force.The de-energized valves‘39.1’and‘39.2’(hydraulic shunt) isolate the pumps‘1.1’and‘1.2’form the brake elements and, at the same time, connect the brake elements with the residual pressure accumulator ‘24.1’and‘24.2’.The hydraulic pressure is further reduced the residual pressure lever through the directional control valves‘53.1’and‘53.2’, the throttling valves ‘56.1’and‘56.2’as well as the cam-controlled pressure relief valves‘60.1’and‘60.2’connected in parallel.The opening time of the above valves determines the threshold time, it can be adjusted through the throttling valves‘59.1’and‘59.2’in a range of 0.2 and 1.0 s. The minimum pressure valve of the open valves‘60.1’and‘60.2’is equivalent to the residual pressure valve and is limited by the final position of the mechanical cam plate.The residual pressure valve is reached after a prolon-gated threshold time of approx.0.1s.For a fine adjustment of the threshold curve and as an additional safety measure ,two throttling valves‘57’are provided for the respective residual pressure value. These components permit the pressure reduction characteristic (braking curve) to be variably adjusted (depending on requirements) and reproduced at any time.The capacity of the residual pressure accumulator is adapted to the maximum braking time of the winder, under consideration of the opening cross sections of the valves ‘57’and of the leakage rate of all valves. The time of maintaining residual pressure is abt.50% longer than the maximum braking time.When the winder comes to a standstill, a time element is started. After abt.2s, the valve‘63’is opened by a starting pulse and the residual pressure reduced to zero. At the same time, the residual pressure accumulator not needed is discharged through the pressure relief valve‘25.1’or‘25.2’(the valve is energized for a short moment).The possibility of adjusting and reproducing the braking curve between application pressure and residual pressure is of particular importance since, within this period, rope vibrations may occur which, with Koepe winders, may cause a slipping of ropes.The valves‘58’，‘65’，and‘66’as well as‘53’and‘39’are monitored for their position and, prior to the start of the winder releasing the safety brake checked for conformity.Furthermore, the starting and end positions of all curves are checked for conformity and thus also for correct functioning.During the safety braking, the pressure relief valves‘43.1’and‘43.2’remain operative.2.2.5 Releasing the safety brakeSince the control system including the pump motors is de-energized as soon as safety braking is started, the brake control system is in a resting state. The system is depressurized and the brake applied.The power required for the pump motors‘3.1’and‘3.2’and the control system is available.The system can be started when1. the electrical monitoring system does not signal any failure.2.all prerequisites for starting the pumps‘1.1’and‘1.2’are fulfilled.3.conformity of the valves‘39’、‘53’、‘58’、65‘、65’、‘66’and‘89’is given.The system is started and the brake released as described under items 2.2.1and 2.2.2.。

大学本科毕业设计--英文原文+中文翻译

Library of C the CNC industrialdeveloped tens of thousands and educational field, he hasNUMERICAL CONTROLNumerical Control technology as it is known today, emerged in the mid 20th century. It can be traced to the year of 1952, the U.S. Air Force, and the names of John Parsons and the Massachusetts Institute of Technology in Cam-bridge, MA, USA. It was not applied in production manu-facturing until the early 1960's. The real boom came in the form of CNC, around the year of 1972, and a decade later with the introduction of affordable micro computers. The history and development of this fascinating technology has been well documented in many publications.In the manufacturing field, and particularly in the area of metal working, Numerical Control technology has caused something of a revolution. Even in the days before comput-ers became standard fixtures in every company and in many homes, the2machine tools equipped with Numerical Control system found their special place in the machine shops. The recent evolution of micro electronics and the never ceasing computer development, including its impact on Numerical Control, has brought significant changes to the manufacturing sector in general and metalworking in-dustry in particular.DEFINITION OF NUMERICAL CONTROLIn various publications and articles, many descriptions have been used during the years, to define what Numerical Control is. It would be pointless to try to find yet another definition, just for the purpose of this handbook. Many of these definitions share the same idea, same basic concept, just use different wording.The majority of all the known definitions can be summed up into a relatively simple statement:Numerical Control can be defined as an operation of machine tools by the means of specifically coded instructions to the machine control systemThe instructions are combinations of the letters of alpha-bet, digits and selected symbols, for example, a decimal point, the percent sign or the parenthesis symbols. All in-structions are written in a logical order and a predetermined form. The collectionNUMERICAL CONTROLof all instructions necessary to ma-chine a part is called an NC Program, CNC Program, or a Part Program. Such a program can be stored for a future use and used repeatedly to achieve identical machining re-sults at any time.♦ NC and CNC TechnologyIn strict adherence to the terminology, there is a differ-ence in the meaning of the abbreviations NC and CNC. The NC stands for the older and original Numerical Control technology, whereby the abbreviation CNC stands for the newer Computerized Numerical Control technology, a modem spin-off of its older relative. However, in practice, CNC is the preferred abbreviation. To clarify the proper us-age of each term, look at the major differences between the NC and the CNC systems.Both systems perform the same tasks, namely manipula-tion of data for the purpose of machining a part. In both cases, the internal design of the control system contains the logical instructions that process the data. At this point the similarity ends. The NC system (as opposed to the CNC system) uses a fixed logical functions, those that are built-in and perma-nently wired within the control unit. These functions can-not be changed by the programmer or the machine opera-tor. Because of the fixed4wiring of the control logic, the NC control system is synonymous with the term 'hardwired'. The system can interpret a part program, but it does not al-low any changes to the program, using the control features. All required changes must be made away from the control, typically in an office environment. Also, the NC system re-quires the compulsory use of punched tapes for input of the program information.The modem CNC system, but not the old NC system, uses an internal micro processor (i.e., a computer). This computer contains memory registers storing a variety of routines that are capable of manipulating logical functions. That means the part programmer or the machine operator can change the program on the control itself (at the ma-chine), with instantaneous results. This flexibility is the greatest advantage of the CNC systems and probably the key element that contributed to such a wide use of the tech-nology in modern manufacturing. The CNC programs and the logical functions are stored on special computer chips, as software instructions, rather than used by the hardware connections, such as wires, that control the logical func-tions. In contrast to the NC system, the CNC system is syn-onymous with the term 'softwired'.NUMERICAL CONTROLWhen describing a particular subject that relates to the numerical control technology, it is customary to use either the term NC or CNC. Keep in mind that NC can also mean CNC in everyday talk, but CNC can never refer to the older technology, described in this handbook under the abbrevia-tion ofNC. The letter 'C 'stands for Computerized, and it is not applicable to the hardwired system. All control systems manufactured today are of the CNC design. Abbreviations such as C&C or C'n 'C are not correct and reflect poorly on anybody that uses them.CONVENTIONAL AMD CNC MACHININGWhat makes the CNC machining superior to the conven-tional methods? Is it superior at all? Where are the main benefits? If the CNC and the conventional machining pro-cesses are compared, a common general approach to ma-chining a part will emerge: Obtain and study the drawingSelect the most suitable machining methodDecide on the setup method (work holding)Select the cutting toolsEstablish speeds and feedsMachine the part6This basic approach is the same for both types of machin-ing. The major difference is in the way how various data are input. A feedrate of 10 inches per minute (10 in/min) is the same in manual or CNC applications, but the method of applying it is not. The same can be said about a coolant - it can be activated by turning a knob, pushing a switch or programming a special code. All these actions will result in a coolant rushing out of a nozzle. In both kinds of machin-ing, a certain amount of knowledge on the part of the user is required. After all, metal working, particularly metal cut-ting, is mainly a skill, but it is also, to a great degree, an art and a profession of large number of people. So is theappli-cation of Computerized Numerical Control. Like any skill or art or profession, mastering it to the last detail is neces-sary to be successful. It takes more than technical knowl-edge to be a CNC machinist or a CNC programmer. Work experience and intuition, and what is sometimes called a 'gut-feel', is a much needed supplement to any skill.In a conventional machining, the machine operator sets up the machine and moves each cutting tool, using one or both hands, to produce the required part. The design of a manual machine tool offers many features that help the process of machining a part -NUMERICAL CONTROLlevers, handles, gears and di-als, to name just a few. The same body motions are re-peated by the operator for every part in the batch. However, the word 'same 'in this context really means'similar 'rather than 'identical'. Humans are not capable to repeat every process exactly the same at all times - that is the job ofma-chines. People cannot work at the same performance level all the time, without a rest. All of us have some good andsome bad moments. The results of these moments, when*applied to machining a part, are difficult to predict. There will be some differences and inconsistencies within each batch of parts. The parts will not always be exactly the same. Maintaining dimensional tolerances and surface fin-ish quality are the most typical problems in conventional machining. Individual machinists may have their own time 'proven' methods, different from those of their fellow col-leagues. Combination of these and other factors create a great amount of mconsistency.The machining under numerical control does away with the majority of inconsistencies. It does not require the same physical involvement as manual machining. Numerically controlled machining does not need any levers or dials or handles, at least8not in the same sense as conventional ma-chining does. Once the part program has been proven, it can be used any number of times over, always returning consistent results. That does not mean there are no limiting factors. The cutting tools do wear out, the material blank in one batch is not identical to the material blank in another batch, the setups may vary, etc. These factors should be considered and compensated for, whenever necessary.The emergence of the numerical control technology does not mean an instant, or even a long term, demise of all man-ual machines. There are times when a traditional machin-ing method is preferable to a computerized method. For ex-ample, a simple one time job may be done more efficiently on a manual machine than a CNC machine. Certain types of machining jobs will benefit from manual or semiauto-matic machining, rather than numerically controlled ma-chining. The CNC machine tools are not meant to replace every manual machine, only to supplement them.In many instances, the decision whether certain machin-ing will be done on a CNC machine or not is based on the number of required parts and nothing else. Although the volume of partsNUMERICAL CONTROLmachined as a batch is always an important criteria, it should never be the only factor. Consideration should also be given to the part complexity, its tolerances, the required quality of surface finish, etc. Often, a single complex part will benefit from CNC machining, while fifty relatively simple parts will not.Keep in mind that numerical control has never machined a single part by itself. Numerical control is only a process or a method that enables a machine tool to be used in a pro-ductive, accurate and consistent way.NUMERICAL CONTROL ADVANTAGESWhat are the main advantages of numerical control?It is important to know which areas of machining will benefit from it and which are better done the conventional way. It is absurd to think that a two horse power CNC mill will win over jobs that are currently done on a twenty times more powerful manual mill. Equally unreasonable are ex-pectations of great improvements in cutting speeds and feedrates over a conventional machine. If the machining and tooling conditions are the same, the cutting time will be very close in both cases.Some of the major areas where the CNC user can and should expect improvement:10Setup time reductionLead time reductionAccuracy and repeatabilityContouring of complex shapesSimplified tooling and work holdingConsistent cutting timeGeneral productivity increaseEach area offers only a potential improvement. Individ-ual users will experience different levels of actual improve-ment, depending on the product manufactured on-site, the CNC machine used, the setup methods, complexity of fixturing, quality of cutting tools, management philosophy and engineering design, experience level of the workforce, individual attitudes, etc.Setup Time ReductionIn many cases, the setup time for a CNC machine can be reduced, sometimes quite dramatically. It is important to realize that setup is a manual operation, greatly dependent on the performance of CNC operator, the type of fixturing and general practices of the machine shop. Setup time is unproductive, but necessary - it is a part of the overhead costs of doing business. To keep the setupNUMERICAL CONTROLtime to a mini-mum should be one of the primary considerations of any machine shop supervisor, programmer and operator. Because of the design of CNC machines, the setup time should not be a major problem. Modular fixturing, standard tooling, fixed locators, automatic tool changing, pallets and other advanced features, make the setup time more efficient than a comparable setup of a conventional machine. With a good knowledge of modern manufacturing, productivity can be increased significantly.The number of parts machined under one setup is also important, in order to assess the cost of a setup time. If a great number of parts is machined in one setup, the setup cost per part can be very insignificant. A very similar re-duction can be achieved by grouping several different oper-ations into a single setup. Even if the setup time is longer, it may be justified when compared to the time required to setup several conventional machines.Lead Time ReductionOnce a part program is written and proven, it is ready to be Bsed again in the future, even at a short notice. Although the lead time for the first run is usually longer, it is virtually nil for any subsequent run. Even if an engineering change of the part design12requires the program to be modi tied, it can be done usually quickly, reducing the lead time.Long lead time, required to design and manufacture sev-eral special fixtures for conventional machines, can often be reduced by preparing a part program and the use of sim-plified fixturing. Accuracy and RepeatabilityThe high degree of accuracy and repeatability of modern CNC machines has been the single major benefit to many users. Whether the part program is stored on a disk or in the computer memory, or even on a tape (the original method), it always remains the same. Any program can be changed at will, but once proven, no changes are usually required any more. A given program can be reused as many times as needed, without losing a single bit of data it contains. True, program has to allow for such changeable factors as tool wear and operating temperatures, it has to be stored safely, but generally very little interference from the CNC pro-grammer or operator will be required. The high accuracy of CNC machines and their repeatability allows high quality parts to be produced consistently time after time. Contouring of Complex ShapesNUMERICAL CONTROLCNC lathes and machining centers are capable of con-touring a variety of shapes. Many CNC users acquired their machines only to be able to handle complex parts. A good examples are CNC applications in the aircraft and automo-tive industries. The use of some form of computerized pro-gramming is virtually mandatory for any three dimensional tool path generation.Complex shapes, such as molds, can be manufactured without the additional expense of making a model for trac-ing. Mirrored parts can be achieved literally at the switch of a button. Storage of programs is a lot simpler than storage of patterns, templates, wooden models, and other pattern making tools.Simplified Tooling and Work HoldingNonstandard and 'homemade' tooling that clutters the benches and drawers around a conventional machine can be eliminated by using standard tooling, specially designed for numerical control applications. Multi-step tools such as pilot drills, step drills, combination tools, counter borers and others are replaced with several individual standard tools. These tools are often cheaper and easier to replace than special and nonstandard tools.Cost-cutting measures have forced many tool suppliers to keep a low or even a nonexistent inventory, increasing the delivery lime14to the customer. Standard, off-the-shelf tooling can usually beob-tained faster then nonstandard tooling.Fixturing and work holding for CNC machines have only one major purpose - to hold the part rigidly and in the same position for all parts within a batch. Fixtures designed for CNC work do not normally require jigs, pilot holes and other hole locating aids.♦ Cutting Time and Productivity IncreaseThe cutting time on the CNC machine is commonly known as the cycle time - and is always consistent. Unlike a conventional machining, where the operator's skill, experi-ence and personal fatigue are subject to changes, the CNC machining is under the control of a computer. The small amount of manual work is restricted to the setup andload-ing and unloading the part. For large batch runs, the high cost of the unproductive time is spread among many parts, making it less significant. The main benefit of a consistent cutting time is for repetitive jobs, where the production scheduling and work allocation to individual machine tools can be done very accurately.The main reason companies often purchase CNCma-chines is strictly economic - it is a serious investment. Also, having a competitive edge is always on the mind of every plant manager. The numerical control teclmology offers excellent means to achieve a significant improvement in the manufacturing productivity and increasing the overall quality of the manufactured parts. Like any means, it has to be used wisely and knowledgeably. When more and more companies use the CNCtechnology, just having a CNC machine does not offer the extra edge anymore. Thecom-panies that get forward are those who know how to use the technology efficiently and practice it to be competitive in the global economy.To reach the goal of a major increase in productivity, it is essential that users understand the fundamental principles on which CNC technology is based. These principles take many forms, for example, understanding the electronic cir-cuitry, complex ladder diagrams, computer logic, metrol-ogy, machine design, machining principles and practices and many others. Each one has to be studied and mastered by the person in charge. In this handbook, the emphasis is on the topics that relate directly to the CNC programming and understanding the most common CNC machine tools, the Machining Centers and the lathes (sometimes also called the Turning Centers). The part quality consideration should be very important to every programmer and ma-chine tool operator and this goal is also reflected in the handbook approach as well as in the numerous examples.TYPES OF CNC MACHINE TOOLSDifferent kinds of CNCmachines cover an extremelylarge variety. Their numbersare rapidly increasing, as thetechnology developmentadvances. It is impossible toiden-tify all the applications,they would make a long list.Here is a brief list of some ofthe groups CNC machines canbe part of: *Mills and Machining centersLathes and Turning CentersDrilling machines CNC machining centers andlathes dominate the number ofinstallations in industry. Thesetwo groups share the marketjust about equally. Someindustries may have a higherneed for one group ofmachines, depending on their □ Boring mills and Profilers □ EDM machines □ Punch presses and Shears □ Flame cutting machines □ Routers □ Water jet and Laser profilers □ Cylindrical grinders □ Welding machines □ Benders, Winding and Spinning machines, etc.needs. One must remember that there are many different kinds of ladies and equally many different kinds ofma-chining centers. However, the programming process for a vertical machine is similar to the one for a horizontalma-chine or a simple CNC mill. Even between differentma-chine groups, there is a great amount of general applica-tions and the programming process is generally the same. For example, a contour milled with an end mill has a lot in common with a contour cut with a wire.♦ Mills and Machining Centers Standard number of axes on a milling machine is three - the X, Y and Z axes. The part set on a milling system is al-ways stationary, mounted on a moving machine table. The cutting tool rotates, it can move up and down (or in and out), but it does not physically follow the tool path.CNC mills - sometimes called CNC milling machines - are usually small, simple machines, without a tool changer or other automatic features. Their power rating is often quite low. In industry, they are used for toolroom work, maintenance purposes, or small part production. They are usuallydesigned for contouring, unlike CNC drills.CNC machining centers are far more popular and effi-cient than drills and mills, mainly for their flexibility. The main benefit the user gets out of a CNC machining center is the ability to group several diverse operations into a single setup. For example, drilling, boring, counter boring, tap-ping, spot facing and contour milling can be incorporated into a single CNC program. In addition, the flexibility is enhanced by automatic tool changing, using pallets to minimize idle time, indexing to a different side of the part, using a rotary movement of additional axes, and a number of other features. CNC machining centers can be equipped with special software that controls the speeds and feeds, the life of the cutting tool, automatic in-process gauging and offset adjustment and other production enhancing and time saving devices.There are two basic designs of a typical CNC machining center. They are the vertical and the horizontal machining centers. The major difference between the two types is the nature of work that can be done on them efficiently. For a vertical CNC machining center, the most suitable type of work are flat parts, either mounted to the fixture on the ta-ble, or held in a vise or a chuck. The work that requires ma-chining on two or more faces m a single setup is more de-sirable to be done on a CNC horizontal machining center. An good example is a pump housing and other cubic-like shapes. Some multi-face machining of small parts can also be done on a CNC vertical machining center equipped with a rotary table.The programming process is the same for both designs, but an additional axis (usually a B axis) is added to the hori-zontal design. This axis is either a simple positioning axis (indexing axis) for the table, or a fully rotary axis for simul-taneous contouring. This handbook concentrates on the CNC vertical ma-chining centers applications, with a special section dealing with the horizontal setup and machining. The program-ming methods are also applicable to the small CNC mills or drilling and/or tapping machines, but the programmer has to consider their restrictions.♦ Lathes and Turning CentersA CNC lathe is usually a machine tool with two axes, the vertical X axis and the horizontal Z axis. The main feature of a lathe that distinguishes it from a mill is that the part is rotating about the machine center line. In addition, the cut-ting tool is normally stationary, mounted in a sliding turret. The cutting tool follows the contour of the programmed tool path. For the CNC lathes with a milling attachment, so called live tooling, the milling tool has its own motor and rotates while the spindle is stationary.The modem lathe design can be horizontal or vertical. Horizontal type is far more common than the vertical type, but both designs have their purpose in manufacturing. Sev-eral different designs exist for either group. For example, a typical CNC lathe of the horizontal group can be designed with a flat bed or a slant bed, as a bar type, chucker type or a universal type. Added to these combinations are many ac-cessories that make a CNC lathe an extremely flexible ma-chine tool. Typically, accessories such as a tailstock, steady rests or follow-up rests, part catchers,pullout-fingers and even a third axis milling attachment are popular compo-nents of the CNC lathe. ?CNC lathe can be veiy versatile - so versatile in fact, that it is often called a CNC TurningCenter. All text and program examples in this handbook use the more traditional term CNC lathe, yet still recogniz-ing all its modern functions.中文翻译：数控正如我们现在所知，数控技术出现于20世纪中叶。

毕业设计(英文翻译)

附录G：英文翻译参考（要求学生完成与论文有关的外文资料中文字数5000字左右的英译汉，旨在培养学生利用外文资料开展研究工作的能力，为所选课题提供前沿参考资料。

）毕业设计（英文翻译）题目系别：专业：班级：学生姓名：学号：指导教师：一位从事质量管理的人约瑟夫·朱兰出生于圣诞夜,1904 在罗马尼亚的喀尔巴阡山脉山中。

他青年时期的村庄中贫穷、迷信和反犹太主义甚是猖獗。

1912年朱兰家搬到了明尼阿波尼斯州，虽然充满了危险，但是它却让一个男孩充满信心和希望。

从如此多了一个在质量观念的世界最好改革者之一。

在他90年的生活中，朱兰一直是一个精力充沛的思想者倡导者，推动着传统的质量思想向前走。

因为九岁就被雇用,朱兰表示在他的生活工作上永不停止。

记者:技术方面如何讲质量?朱兰:技术有不同方面:一、当然是精密。

物的对精密的需求像电子学、化学…我们看来它们似乎需要放大来说,和重要的原子尘的有关于质量。

要做到高精密具有相当大的挑战，而且我们已经遇见非常大的挑战。

另外的一个方面是可信度－没有失败。

当我们举例来说建立一个系统，同类空中交通管制的时候,我们不想要它失败。

我们必须把可信度建入系统。

因为我们投入很大的资金并依赖这些系统，系统非常复杂，这是逐渐增加的。

除此之外,有对公司的失败费用。

如果事物在领域中意外失败,可以说，它影响民众。

但是如果他们失败在内部,然后它影响公司的费用,而且已经试着发现这些费用在哪里和该如何免除他们。

因此那些是相当大的因素:精密、可信度和费用。

还有其它的,当然，但是我认为这些是主要的一些。

记者:据说是质量有在美国变成一种产业的可能?朱兰:资讯科技当然有。

已经有大的变化。

在世纪中初期当质量的一个想法到一个检验部门的时候，这有了分开的工作，东西被做坏之后。

检验是相当易错的程序,实际上。

而且无论如何，资讯科技在那天中相当花时间，直到某事已经被认为是否资讯科技是正确的。

应该强调计划，如此它不被错误首先订定。

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Highway Subgrade Construction in Expansive Soil AreasJian-Long Zheng1Rui Zhang2and He-Ping Yang31 Professor and President, ChangSha Univ. of Science and Technology, Chiling Road 45, Changsha, Hunan 410076, China. E-mail: zjl_csust@2 Ph.D. Candidate and Lecturer, School of Highway Engineering, ChangSha Univ. of Science and Technology, Chiling Road 45, Changsha, Hunan 410076, China. E-mail: zr_csust@3Professor, School of Highway Engineering, ChangSha Univ. of Science and Technology, Chiling Road 45, Changsha, Hunan 410076, China. E-mail: cscuyang@(Accepted 22 May 2007)IntroductionExpansive soil is predominantly clay soil that undergoes appreciable volume and strength changes following a change in moisture content. These volume changes can cause extensive damage to the geotechnical infrastructure, and the damage is often repeatable and latent in the long term (Liao 19848). China is one of the countries with a wide distribution of expansive soils. They are found in more than 20 provinces and regions, nearly 600,000 km2in extent. It has been estimated that the planned highways totaling 3,300 km in length pass through expansive soils areas (Zheng and Yang 200422). Improper highway construction in such areas could well lead to great losses and damage to the environment.In 2002, the Chinese Ministry of Communications (CMOC) sponsored a research project, “A Complete Package for Highway Construction in Expansive Soil Areas,” whose primary objective was to solve expansive soil problems in highway engineering. A research group with personnel from Changsha University of Science and Technology (CUST) was set up. Comprehensive laboratory tests, field investigations, and analyses were carried out, aimed at solving highway engineering problems in several different expansive soil areas. A complete presentation of the results of this research is beyond the scope of this paper, but the research on subgradeconstruction for the Nanning to Youyi Guan (NanYou) highway will be discussed to introduce the laboratory studies performed on soil properties, classification of swelling potential, and engineering properties of expansive filler soils. Field investigations of slope failures in the Ningming area also will be described. Several new techniques for building embankments and treating expansive soil cut slopes also are presented.Site GeologyNingming Basin lies in south China. The region has in an oceanic monsoon climate with long summers and quite short winters. The annual average temperature is 22.1° centigrade and the annual rainfall is about 1,200 mm, falling mostly from April to August. There is a very obvious difference between the rainy and dry seasons. The Ningming Basin is an east–west tectonic faulted basin formed in Q2–4, with deposits of lacustrine mudshale from the Nadu formation (N y) of the Eocene, 1,500 m in thickness. Argillaceous siltstone and little siltstone are present as well. The obliquity of the stratum is about 5°–7°in the middle of the basin, but 22°at the edge. In addition, there are Jurassic and Triassic siltstone and limestone around the basin.A typical geological profile from the Ningming area is shown in Fig. 1. Ningming expansive soils, dark or light gray in color, are of residual origin from the weathering of mudshale or shale from the Nadu formation of the Eocene. Due to the parent rock’s structure, the residual expansive soils have a residual fabric (microbedding and tiny tectonic fissures) originating from the parent rock, and many included ferromanganese nodules. The weathered mudshale, once exposed, collapses rapidly into smaller prism-shaped fragments, which can continue to fragment into smaller and smaller pieces. A great many vertical, cross and horizontal tectonic joints, tectonic fissures, and weathered fissures clearly can be seen in excavated profiles, and a soft interlayer exists between the soil and mudshale layers. The active zone, about 3-m thick (CMOC 1996b10) is several meters below the surface, but nevertheless affected by seasonal climatic changes (Nelson and Miller 199213).Research on Embankment Construction and Its Engineering ApplicationIn expansive soil areas, embankments filled with expansive soils usually encounter nonuniform settlement (Hu et al. 20044). Road shoulders, which cannot be compacted, adequately, develop large longitudinal cracks, and large wave deformations appear along the cross section. The bearing capacity of the pavement decreases substantially as a result of the reduced resilient modulus of the subgrade, and slope surface failures usually occur. Embankment failures usually involve three phases: shrinkage cracks form in the slope during the dry season; water infiltrates into the soil mass through the cracks in the subsequent wet season, with soil swelling; and finally, the shear strength of the clayey soil deteriorates to the extent that the shear forces within the slope cannot be adequately resisted, resulting in a localized slope failure. Generally, times until failure can range from several months to several years (Zhang et al. 2005).Selection of Embankment FillerIt has been stipulated in China’s Technical Specification for the Construction of Highway Subgrades (CMOC 1996a11) that expansive soil with a high swelling potential should not be used as embankment fill material due to its poor water stability. Expansive soil with medium swelling potential can be used as filler only after it has been improved. Expansive soil with low swelling potential can be used as filler according to the climate, hydrological conditions, and the highway classification, but the side slopes and top of the embankment should be protected. In light of these specifications, nearly five million m3of expansive soils and highly weathered mudshale excavated for the construction of the NanYou highway in the Ningming area could not be used as embankment filler without being improved, because they are characterized as having moderate swelling potential.Consequently, the research group studied stabilizing expansive soils with calcium lime, Portland cement, and mixtures of lime and cement in the laboratory. The resulting clay contents, compressibility, California bearing ratio (CBR), and swelling capabilities showed that the improving effect of the lime was the greatest (Chen 20042). For light-gray expansive soil, the optimum lime content was determined to be 3%, and the optimum moisture content was 15.2%. These values were determined by compaction tests at 2,684.9 kj/m3. The resulting CBR and soakedswelling ratio satisfied the specifications for fill. However, in practice it is very hard to mix lime and expansive soil properly because the natural moisture content of the soil is so very high. The soil easily agglomerates, so the operation is complicated and requires heavy construction machinery. In addition, the high price of lime will greatly increase highway construction costs, and lime dust that inevitably escapes during spreading will do some harm to the environment. Therefore, lime stabilization is not popular in engineering practice. However, if the expansive soils must be replaced by nonexpansive material transported from several hundred kilometers away that would entail high costs and environmental degradation.According to the Chinese specification, the CBR of fill in an upper embankment (less than 1.5 m below the embankment surface) should reach 4%, and it should be 3% for the material in the lower embankment (more than 1.5 m below the surface). In light of the routine soaking that is part of the CBR test method, the CBR of expansive soils can rarely reach 3%. However, according to the change of CBR with moisture content (Fig. 3), and the change in swell percent of CBR samples with time , the research group found that if the CBR samples were not soaked, the CBR was very high at relatively low moisture content. Therefore, research was carried out on the feasibility of using expansive soils as fill, including research on evaluating their bearing capacity and the field compaction control of expansive soil fill.Changes in California bearing ratio with moisture contentEvaluating the Bearing Capacity of Expansive SoilsSubgrade “stiffness” controls the total pavement thickness, especially with flexible pavements. So, it is very important to correctly test the stiffness of subgrade materials, and the conditions (density and moisture content) at which the material is tested should be considered. The CBR testing condition stipulated in China’s Test Methods of Soils for Highway Engineering (CMOC 1996b) involves compacting the material in a mold (0.152 m in diameter and 0.120 m high) and soaking for 4 days under a surcharge weight of 50 N, corresponding to 2.7 kPa. However, for clayey materials, this procedure leads to only the upper and lower parts of the sample becoming saturated or nearly saturated, because of the low permeability of clay, especially for expansive soils, and the air entrapped in the sample. The measuredCBR then only corresponds to the saturated soil in the shallow upper part, where the soil has disintegrated under the light surcharge after soaking (Uzan 1998).However, suppose expansive soil is used as fill in the lower embankment and nonexpansive fill material is used in the upper as a moisture barrier. Then, the surface of the lower embankment would not be soaked, and the upward pressure on the surface would no longer be 50 N. Therefore, the research group studied a modified CBR test on expansive soil simulating such field conditions. The study mainly focused on weathered mudshale, whose swell potential is medium, and which formeda large percentage of excavated material in the construction of the NanYou Highway.1.Li, S. L., Qin, S. J, and Bo, Z. Z. (1992). Studies on the engineering geology of expansive soils in China, Jiangsu Science and Technology Publishing House, Nanjing, China, 212.2.Liao, S. W. (1984). Expansive soil and railway engineering, Chinese Railway Publishing Press, Beijing, 374.3.Mao, Y. C. (2006). “Tests on the feasibility of using expansive soil as embankment fill.” MSc thesis, Changsha Univ. of Science and Technology, Changsha, China.4.Ministry of Communications of the People's Republic of China (CMOC). (1996a). Technical specifications for the construction of highway subgrades JTJ033-95., Renmin Communication Press, Beijing.5.Ministry of Communications of the People's Republic of China (CMOC). (2003). Specifications for the design of highway subgrades JTJ013-2002, Renmin Communication Press, Beijing, 156.6.Ministry of Communications Second Highway Survey Design and Research Institute of China (CMOC). (1996b). Handbook of design for highway subgrades, 2nd Ed., Renmin Communication Press, Beijing, 407.7.Uzan, J. (1998). “Characterization of clayey subgrade materials for mechanistic design of flexible pavements.” Transportation Research Record. 1629, National Research Council, Transportation Research Board, Washington, D. C., 188–196.8.Wei, T. Z. (1990). “Some factors influencing on deformation of foundation on expansive soil in Guangxi.” Proc., 1st Chinese Symp. on Expansive Soils, Southwest Jiaotong University, Chengdu, 232–238.9.Yang, H. P. (1999). “Approach to strengthening expansive soil embankment side slope with geogrid.” Chinese J. Highw., 16(3), 42–46.10.Yang, H. P., Qu, Y. X., and Zheng, J. L. (2005). “New developments in studies of Ningming expansive soils.” Chinese J. Geotech. Eng., 17(9), 981–987.。

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