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外文文献翻译译稿和原文

外文文献翻译译稿1卡尔曼滤波的一个典型实例是从一组有限的，包含噪声的，通过对物体位置的观察序列（可能有偏差）预测出物体的位置的坐标及速度。

在很多工程应用（如雷达、计算机视觉）中都可以找到它的身影。

同时，卡尔曼滤波也是控制理论以及控制系统工程中的一个重要课题。

例如，对于雷达来说，人们感兴趣的是其能够跟踪目标。

但目标的位置、速度、加速度的测量值往往在任何时候都有噪声。

卡尔曼滤波利用目标的动态信息，设法去掉噪声的影响，得到一个关于目标位置的好的估计。

这个估计可以是对当前目标位置的估计（滤波），也可以是对于将来位置的估计（预测），也可以是对过去位置的估计（插值或平滑）。

命名[编辑]这种滤波方法以它的发明者鲁道夫.E.卡尔曼（Rudolph E. Kalman）命名，但是根据文献可知实际上Peter Swerling在更早之前就提出了一种类似的算法。

斯坦利。

施密特（Stanley Schmidt）首次实现了卡尔曼滤波器。

卡尔曼在NASA埃姆斯研究中心访问时，发现他的方法对于解决阿波罗计划的轨道预测很有用，后来阿波罗飞船的导航电脑便使用了这种滤波器。

关于这种滤波器的论文由Swerling（1958）、Kalman (1960)与Kalman and Bucy（1961）发表。

目前，卡尔曼滤波已经有很多不同的实现。

卡尔曼最初提出的形式现在一般称为简单卡尔曼滤波器。

除此以外，还有施密特扩展滤波器、信息滤波器以及很多Bierman, Thornton开发的平方根滤波器的变种。

也许最常见的卡尔曼滤波器是锁相环，它在收音机、计算机和几乎任何视频或通讯设备中广泛存在。

以下的讨论需要线性代数以及概率论的一般知识。

卡尔曼滤波建立在线性代数和隐马尔可夫模型（hidden Markov model）上。

其基本动态系统可以用一个马尔可夫链表示，该马尔可夫链建立在一个被高斯噪声（即正态分布的噪声）干扰的线性算子上的。

系统的状态可以用一个元素为实数的向量表示。

外文翻译及原文

Pyrolysis of oil sludge first by thermogravimetry/mass spectroscopy (TG/MS) and then in a horizontal quartz reactor with an electrical laboratory furnace under different pyrolysis conditions was carried out. The influence of heating rate from 5 to 20 °Camin-1, final pyrolysis temperature from 400 to 700 °C, various interval holding stage, and catalyst on the products were investigated in detail. The TG/MS results show that pyrolysis reaction of oil sludge starts at a low temperature of about 200 °C, and the maximum evolution rate is observed between the temperatures of 350-500 °C. A higher final pyrolysis temperature, an interval holding stage, and adding catalyst can promote the pyrolysis conversion (in terms of less solid residue production). In all parameters, an interval holding stage for 20 min near the peak temperature of 400 °C can enhance the yield of oil and improve its quality. Three additives used in this work as catalysts do not improve oil product quality markedly in spite of increasing pyrolysis conversion greatly.油泥的裂解首先通过热重/质谱分析（TG / MS），然后在水平石英反应器中具有不同热解条件下的电气实验室炉进行。

自动化专业-外文文献-英文文献-外文翻译-plc方面

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外文翻译英语原文编号01

Vol.25 No.2 PANG Chaoming et al: Methods of Modifying the Brittle (156)DOI 10.1007/s11595-010-1156-yMethods of Modifying the Brittle Behavior ofCementitious CompositesPANG Chaoming1, SUN Wei1, LEUNG Christopher KY2(1.College of Materials Science and Engineering, Southeast University, Jiangsu Key laboratory of Construction Materials, Nanjing 211189,China;2. Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology, Hong Kong, China SAR)Abstract: We put forward effective methods of increasing the tensile strain of cementitiouscomposites with 2% PVA fiber and high fly ash content. The test results show that curing condition hasa significantly effect on the tensile performance. It is approved that the specimens incorporated ap-propriate volume fraction rubber powder and lightweight aggregate greatly increase the tensile strain ofcomposites at medium-term age, but indefinitely at long-term age. To a certain extent, EVA can limitedlyenhance the tensile performance of comentitious composites owing to the formation of polymer membraneand the hindered hydration of cement.Key word: high-ductility cementitious composites (HDCC); tensile properties; high content offly ash; rubber powder; light aggregate; ethylene vinyl alcohol latex powder1 IntroductionCementitious composites are widely used as the majority of structural materials. However, cementitious composites are limited to some special projects due to the inherently brittle behavior. Most efforts have been made to modify the brittle behavior of cementitious composites all along. As a result, the fiber reinforced cementitious composites (FRCC) occurred. In comparison to plain concrete, FRC usually deteriorates the tensile or bending properties by the formation of several cracks and a main crack. In the past two decades, Li, Leung and Wu etc[1-3] investigated the bridging stress of fiber and proposed the theory for high-ductility cementitious composites (here-after abbreviated as HDCCs) or pseudo ductility cemen-titious composites or pseudo strain hardening cementi-tious composites, based on the two nondimensionalized parameters energy absorption rate and normalized flaw size. It has been demonstrated that the ductility behaviors of brittle materials can be achieved by multiple cracks in steady state along the length of the specimen and behave pseudo strain hardening (abbr. PSH). Hereafter, the theories for PSH in the cementitious composites were gradually developed by Li and his co-workers, and the particular theory for “composite design”, based on the micro mechanics parameter, by emphasizing the proper integrant materials and interface was proposed[4,5]. The cementitious composite with high tensile strain capacity of 3%-6%, whose strain capacity is far outperforming conventional cementitious composites, was achieved[6].Recently increasing researchers are interesting to the new type of fiber reinforced cementitious composite. However, it is not easy to achieve PSH in discontinuous random fiber reinforced. Strain due to a little deviation of raw materials occur even if the well-known same mixture proportion of ECC is used due to a little deviation of raw materials. Meanwhile, the design method of existing theory depend on known experimental micro mechanics parameters, such as the fracture toughness, fiber content, fiber strength, fiber distribution, the bridging stress and interface properties between fiber matrix, etc. Moreover, it is very difficult to achieve the accurate fiber distribu-tion and bridging stress due to the randomization and inhomogeneity of the distribution of fiber in composites. But the micromechanical parameters and the ductile be-havior is strongly affected by the bridging stress governed by fiber debonding, fiber bending, fiber rupture, matrix spalling and their coupling[2].The focus in the current study is to discover the ef-ficacious methods to increase the tensile strain of HDCC. It is well know that curing conditions have a significantly©Wuhan University of Technology and Springer-Verlag Berlin Heidelberg 2010 (Received: Jan. 6, 2009; Accepted: Oct. 16, 2009)PANG Chaoming(庞超明): Ph D candidate; E-mail: pangchao@seu. edu. cnJournal of Wuhan University of Technology-Mater. Sci. Ed. Feb.2010157conditions were used for comparison, considering that the structures in practice project are often exposed to different environment and different curing condition are usually applied according to the lab environment in the different researches. For the brittle cementitious com-posites, the matrix cracking strength, which is determined by the matrix toughness and the largest crack or flaw in the stress section of specimen provided that the matrix cracking is controlled by fracture process, does not de-crease unlimitedly but reaches a lower bound at steady state cracking stress with the growing flaw size [7]. Moreover, the discontinuous pre-existing flaw or mi-cro-voids may relax the crack-tip stress triaxiality, dif-fuse the intensity of crack-tip stress singularity and consume more energy. To ensure the formation of multiple cracks, it is desirable to introduce a rtificial flaws in the matrix to reduce its crack tip toughness and increase the crack size due to energy absorption of flaw [8]. Therefore, different materials, such as rubber powder and fine lightweight aggregate, were added to the composites to increase the strain capacity.2 ExperimentalSpecial green island brand P·II 52.5 cement was used. The range of particle size of fly ash is mainly 2-10 μm, and the active index of compressive strength at 7 days, 28 days and 90 days are the 86%, 84% and 96% respectively followed by ASTM C311-04. Polyvinyl alcohol fiber (abbr. PVAF) produced by Japan Kuraray Limited Corporation was used, and its density, length, diameter were 1.3 g/cm 3, 12 mm, 38 μm respectively,also its elastic modulus and rate of elongation is 33 GPaand 6.5% respectively.The particle size of silica fume, silica filler and silica sand used is 1-20 μm, 1-15 μm and 50-200 μm respec-tively. ADVA105 superplastics admixture (abbr. Sp) was ％produced by Grace Co.LTD and its solid content is 23. SP4000 (abbr. SP4), which is ethylene vinyl alcohol (abbr. EVA) latex powder and is produced by Japan Kuraray Trading Co.LTD, was used in this study. The particle size of lightweight aggregate (abbr. LA) is between 1 mm and 3 mm, whose specific density is 1 500 kg/m 3, and the loose volume weight is about 780 kg/m 3. Rubber pow-der with the particle size of 0.4 mm was also used.The specimen was demoulded 24 hours after casting, where the temperature and relative humidity was about 20±2 ℃ and (60±5)％ respectively, then cured in water at curing room , where the temperature is 27 ℃ (ac-cording to the BS standard). The nominal sizes used for tensile performance and compressive performance are about 350×50×15 mm and 40×40×40 mm respec-tively. The dimensions of the specimen were accurately measured by vernier caliper and all the specimens were polished to smooth surface before testing to obtain ac-curate experimental results, and at least three specimens were tested at each age.The tensile performance was tested under the dis-placement control in the MTS810-25 kN materials test-ing system with the displacement rate of 0.15 mm/min. Linear variable displacement transducer was used to measure the displacement at the gage length of 150 mm for the more accuracy purpose. The first crack strain εfc , the peak strain εp and the maximum strain εm repre-sent to the strain corresponding to the first crack stress σTc when the first crack occurred, peak stress σTp when the stress reaches the peak, and the strain when the stress descends up to 90% σTp , respectively.3 Results3.1 Effect of curing conditions on me-chanical properties of HDCCAccording to previous work, two mix proportions shown in Table 1 were used, i e , SP4 and W1 with high volume fraction fly ash and low ratio of water to binder (cement and fly ash). Table 1 Mix proportion in mass of HDCC No. cement FA SP4 sand water Sp PVAF SP4 1 3.9 0.1 1.0 1.1 0.022 0.090 W1 1 4.0 0 1.0 1.0 0.023 0.096For the purpose of comparing the effect of different curing condition on the tensile performance, four types of curing conditions were applied in mixture SP4 as fol-lowing: full dry curing in room temperature condition after demoulded, which corresponds to symbol D in the denominated title in Table 2, dry curing in room tem-perature condition after 3-day curing in water corre-sponding to symbol W3D, dry curing in room tempera-ture condition after 7-day water curing corresponding to symbol W7D, and 28-day water curing corresponding to symbol W. The only two types of curing conditions wereused in mixture W1: dry curing in room temperature condition after 7 days water curing and full water curing. Table 2 list the test results of the tensile strength and strain and compressive strength on different curing con-ditions at the age of 7-day and 28-day.Vol.25 No.2 PANG Chaoming et al : Methods of Modifying the Brittle …1583.2 Effect of rubber powder on mechanic-al properties of HDCCThe specimen without rubber powder is regarded as control specimen, and two mixtures of HDCCs with the rubber powder were prepared. SR7 and SR11 represent for HDCC of the volume fraction of 7% and 11%, re-spectively. For estimating the long-term performance, the accelerated curing method was conducted, that is, after cured in water for 7 days, at least three specimens were put to the heat curing room for 72 hours, where the temperature and relative humidity are 80 ℃％and 95respectively, the mechanical performance was measured after being cooled down in the room temperature condi-tion. The mix proportion used and test results are sum-marized in Table 3, Table 4 respectively. Heat curing corresponds to symbol HC. Fig.1 shows the tensile stress versus strain curves of SR7 and SR11 at 28 days.3.3 Effect of lightweight aggregate onmechanical properties of HDCC For the purpose of researching the effect of light-weight aggregate on the tensile strain of HDCC with highflyash content, the volume fraction of 3.5% was incor-porated into the mixture, and the mix proportion was listed in Table 5. The specimen FA3 and FA3LA corre-spond to control specimen and specimen with lightweight aggregate, respectively.The test results are shown in Table 6. The condition of heat curing is the same as mentioned above. Fig.2(a) and Fig.2(b) showed the typical stress vs strain curve of FA3 and FA3LA3.5 at different age: 7 days, 28 days and heat curing 3 days.Table 2 Test results of HDCC on different curing conditionsSP4D SP4W3D SP4W7D SP4W W1 7-day 28-day 7-day 28-day 28-day 90-day 7-day 28-day W7 W28 W7DσTfc /MPa 2.68 2.36 2.91 2.54 3.26 3.28 2.70 3.36 2.76 3.65 3.62 εfc /% 0.080 0.069 0.075 0.096 0.080 0.089 0.119 0.060 0.088 0.047 0.128 σTp /MPa 3.30 3.39 3.76 3.14 4.07 3.62 3.17 4.02 3.27 3.81 4.69εp /% 1.53 3.95 2.69 2.56 2.82 2.58 2.78 0.77 1.050.35 2.94 εm /% 1.69 4.28 2.80 2.79 3.54 2.66 2.97 1.81 1.360.54 3.39 σcom /MPa 22.8 27.2 — — — — 23.4 36.0 35.8 58.9 — Table 3 Mix proportion in mass of HDCC with different volume fraction of rubber powder No. Cement FA Filler Sand Rubber Water Sp PVAFControl 1 1.50 0.25 1.00 0 0.63 0.015 0.057 SR7 1 1.50 0.25 0.65 0.163 0.58 0.020 0.055 SR11 1 1.50 0.25 0.40 0.263 0.58 0.020 0.055 Table 4 Test results of HDCCs with different volume fraction of rubber powderControl SR7 SR117-day 28-day 90-day 7-day 28-day HC 7-day 28-day HCσTfc /MPa 3.58 4.61 3.81 2.31 2.60 3.63 2.19 2.31 3.28 εfc /% 0.050 0.042 0.027 0.036 0.022 0.039 0.034 0.051 0.041 σTp/MPa 4.30 5.05 4.53 2.49 3.00 3.81 2.72 3.18 3.57 εp /% 1.33 0.84 0.29 0.31 0.58 0.16 1.04 2.15 0.20 εm/% 1.59 0.98 0.39 0.54 1.07 0.71 1.40 2.49 0.34 σcom /MPa 49.6 66.2 — 29.7 35.7 40.5 24.8 31.4 37.0 Table 5 Mix proportion in mass No. Cement FA LA Sand Water Sp PVAF FA3 1 3 — 1 1 0.025 0.056 FA3LA 1 3 0.16 1 1 0.028 0.056 Table 6 Test results of HDCCs with or without lightweightaggregate FA3 FA3LA 7 d 28 d 90 d HC 7 d 28 d 90 d HCσTfc /MPa 1.42 2.68 3.60 4.38 2.86 3.15 3.25 6.42εfc /% 0.015 0.044 0.031 0.022 0.025 0.045 0.040 0.037 σTp /MPa 2.91 3.46 4.86 4.86 2.86 3.91 3.92 6.49εp /% 0.04 0.58 0.29 0.08 0.03 1.96 0.23 0.04 εm /% 1.16 0.96 0.66 0.31 1.40 2.07 0.54 0.38 σcom/MPa 21.5 44.7 69.5— 19.0 44.2 74.8 —Journal of Wuhan University of Technology-Mater. Sci. Ed. Feb.20101593.4 Effect of EVA powder on mechanicalproperties of HDCCA series of HDCCs specimens with or without EVA powder were also prepared, cured and tested at prescribed age followed by the test procedure. The condition of heat curing is also the same as mentioned above. The mix proportion used is listed in Table 7, and test results of tensile properties are presented in Table 8 and Fig.2(c) respectively. S is the control specimen, and SS4 is representative for HDCC with EVA powder.4 Discussion It can be concluded that the curing conditions have a great effect on the tensile properties from Table 1 and Table 2. The tensile properties exhibit a great difference at 28 days due to different curing condition for mixture SP4 and mixture W1. The HDCC cured in water per-forms better than that in room temperature condition atthe early age, however, as the age increases, the tensileperformance of HDCCs cured in room temperature condition shows an increasing tendency while that curedin the water decreases. The tensile strain of specimensthat of W3D is similar to that of W7D at 28 days, whichtest results also show the ultimate tensile strength has not direct relationship with the tensile strain, and high tensile strain do not mean low tensile strength, and vice versa . That can be explained as follows: curing condi-tion plays a significant influence on microstructure and macroscopical performance of cementitious composites. For fiber reinforced cementitious composites, there exists a distinctive layer of interface zone about 30-50 μm away from the fiber surface [9]. Also the interface will strongly influence the toughness of the compositesand frictional bond [10]. Generally the interface zone is considerable weaker than the matrix due to the large calcium hydroxide crystals and higher porosity for the FRCCs with steel fiber or polypropylene fiber [9], but thePVA fiber is a special organic fiber to the cementitiouscomposites. The majority of fibers used to the cementi-tious composites, such as steel fiber, polypropylenefiber,etc , will not react with the hydration products of cement, but the investigations by Akers show that [11], the PVA fiber performs surprisingly high chemical bonding between the PVA fiber and cement hydrationproducts due to the strong hydrophilic characteristic or hydrogen intermolecular bond induced by the hydroxyl groups, and as the age increase, while there are no evi-dent change in fiber properties, the bonding strengthbetween fiber and cement-based matrix will increase due to an increase in interface bond with age. The re-searches by Kanda T etc also shows that the apparent chemical bonding between PVA fiber and cement ma-，trix independent of the water-to cement ratio of matrix, is relatively stable and up to 30-40 MPa, but the value of friction bond, affected by water to cement ratio, is be-tween 2.2 MPa to 4.4 MPa when the water to cementvaries from 0.62 to 0.27[12]. Through the investigation by Li and his co-workers [3], only the FRCC with the appropriate fracture toughness of matrix and frictional Table 7 Mix proportion with or without EVA in mass No. Cement FA SF SP4 Sand Water Sp PVAF S 1 3.85 0.1 — 1 1.21 0.033 0.096 SS4 1 3.60 0.1 0.1 1 1.21 0.032 0.096 Table 8 Test results of HDCCs with or without EVAS SS47 d 28 d HC 7 d 28 d HCσTfc /MPa 1.15 3.32 4.37 1.86 3.14 3.89 εfc/% 0.021 0.067 0.029 0.057 0.086 0.049 σTp /MPa 1.94 3.43 4.90 2.03 3.42 4.75 εp /% 0.20 1.18 0.33 0.49 1.24 0.60εm /% 0.54 1.63 0.40 1.55 1.73 0.74 σcom /MPa 13.0 33.5 — 13.0 35.4 — (a) FA3 (b) FA3LA (c) S and SS4Fig.2 Stresses vs. Strain curves of FA3, FA3LA, S and SS4 at different ageVol.25 No.2 PANG Chaoming et al: Methods of Modifying the Brittle (160)and high strain capacity of FRCC can dominantly be achieved by using PVA fiber, and the interfacial fric-tional stress for FRCC with PSH behavior show the relative definite requirement and shall preferably be between 0.8 to 2.0 MPa[13], and the value can be achieved by applying oil agent[14]. In the present study, the PVA fiber, which had been coated with the oiling agent by Japan Kuraray Co. LTD, was employed. Ow-ing to low water to binder ratio and high content of fly ash (W/B＝0.20, FA/C＝4.0), and the specimens were kept only for 0-7 days in water and then longer than 20 days cured in room temperature condition, where there is no enough water for cement hydration, therefore they exhibit relative lower hydration degree and larger shrinkage than those cured in the water in all time. The lower hydration degree and larger shrinkage result in relatively lower frictional bond and weaker interface between PVA fiber and matrix[15]. Therefore, the former forms relatively looser structure and satisfies the re-quirement of low interfacial frictional stress, therefore performs better in strain hardening. Also the failure pat-tern of fiber rupture can be observed in testing process of the latter.In general, the definite range of interfacial fric-tional stress for achieving PSH behavior of FRCC, lower ratio of cement to binder, high fly ash content and PVA fiber properties contribute to the effect of curing condition on the tensile behavior.It can be deduced from Table 4, Table 6, Fig.1 and Fig.2 that the tensile strength of HDCC with rubber powder or light aggregate keep on growing, while the tensile strain also increases as the age increases from 7 days to 28 days, then decreased as the age continually grows up to 90 days or when heat curing was applied. That is because the fiber/matrix bond strength should saturate in a duration of less than 14-28 days, and ma-ture much earlier than matrix properties in cementi-tious[16]. But the high content of fly ash will considera-bly lower the chemical bond and delay the mature due to diluting the metal cation concentration on the fiber surface at early age and as a result the strain increases from 7 days to 28 days[17]. But the friction strength and the facture toughness of matrix continue to develop as age increase to 28 days as the second hydration of fly ash continually develop due to activity effect of fly ash under high temperature or at long age. When the imbal-ance of develop rate occurs, the strain decreases with the continual increasing age.From Table 4 and Table 6, not all the specimens show better tensile performance than the control specimen, only the tensile strain of the specimens with 11% volume fraction rubber powder or 3.5% light-weight aggregate increase comparing to the control specimen at 28 days. The specimens FA3 and FA3LA rapidly reach ultimate strength then crack, and only few cracks develop due to the high fracture toughness of matrix and the low friction between matrix and PVA fiber at 7 days, but the specimen can still maintain the considerable strain after cracking owing to fiber gradu-ally being pulled out. And the SR7 also shows the similar tendency at 28 days. It is possible that the frac-ture toughness of matrix develops faster than the chemical bond and the frictional bond due to the low ratio of water to binder and high content fly ash. However, the specimen with the 11% volume fraction rubber pow-der reaches 2.15% in comparison with only 0.84% for the corresponding control specimen and the ultimate strain of with or without lightweight aggregate varies from 1.96% to 0.58%. The similar test results, i e, pre-existing flaw or micro-voids can modify the brittle behavior of HDCC, were observed in the reference[8] as the pre-existing flaw can relax the crack-tip triaxiality, diffuse the intensity of crack-tip stress and consume more energy, and the lager flaw will not influence the cracking strength but reached a lower bound at a steady state of cracking stress.Table 8 and Fig.2 present that the EVA latex powder show a little positive effect on the tensile strain at different age. It is possible that the EVA as a polymer can form a layer polymer membrane, which hinders the hydration of cementitious materials, but the membrane only influences a little hydration process owing to the lower content, about 1% volume fraction, in compos-ites.In summary, the appropriate fracture toughness of matrix and frictional bond between fiber and matrix is necessary conditions to achieve the PSH behavior or high strain capability. The curing condition emphasize particularly on the influence of friction bond, but the incorporation of rubber powder and lightweight lay particular stress on the fracture toughness of matrix. However the incorporation of rubber powder and lightweight aggregate lower the fracture toughness of matrix and facilitate the crack of matrix, which will possibly lower the effect of curing condition on the tensile properties.Journal of Wuhan University of Technology-Mater. Sci. Ed. Feb.2010 1615 ConclusionsSome methods to modifying the brittle behavior of HDCC with high content fly ash are proposed. It is undoubted that curing condition will strongly influence the microstructure of cementitious composites. The test results show that curing condition has a significant ef-fect on the tensile strain of HDCC with high content fly ash, and dry curing condition will show the clear trend to increase the tensile strain of HDCC with high content fly ash. Not all the specimens but the specimens with appropriate volume fracture rubber powder and light-weight aggregate greatly enhance the tensile strain of HDCC at medium-term age, but indefinitely at long-term age impossibly because disconnected pre-existing flaw or micro-voids may relax the crack-tip, diffuse the intensity of crack-tip stress and significantly consume energy. To a certain extent, EVA can enhance the tensile performance of HDCC owing to the hindered hydration of cement based materials as a result of the formation of polymer membrane. But it is possible that the incorporation of rubber powder and lightweight will lower the effect of curing condition on the tensile per-formance.It also experimentally demonstrates that some specimens rapidly reach ultimate strength and crack, but some specimen can still maintain the considerable strain after cracking owing to fiber gradually being pulled out. The tensile stress keeps increasing, but the tensile strain firstly increases then decreases as the age continually grows because of the imbalance of develop rate between bond strength and matrix properties. References[1]LI V C and LEUNG C K Y. Steady-state and MultipleCracking of Short Random Fiber Composites[J]. Journal ofEngineering Mechanics, 1992, 118(11): 2 246-2 264[2]LEUNG C K Y and LI V C. Effect of Fiber Inclination onCrack Bridging Stress in Fiber Reinforced Brittle MatrixComposites[J]. Journal of Mechanical Physics, 1992, 40(6):1 333-1 362[3]LI V C and WU H C. Conditions for PseudoStrain-Hardening in Fiber Reinforced Brittle MatrixComposites[J]. Applied Mechanics Revolution, 1992, 45(8):390-398[4]LI V C, MISHRA D K and WU H C. Matrix Design forPseudo-Strain-Hardening Fiber Reinforced CementitiousComposites[J]. Materials and Structures, 1995, 28: 586-595 [5]KANDA T, LI V C and Member of ASCE. New Micro-mechanics Design Theory for Pseudostrain Hardness Ce-mentitious Composite[J]. Journal of Engineering Me-chanics, 1999, 125(4): 373-381[6]LI V C, WANG S and WU C. Tensile Strain- HardeningBehavior or Polyvinyl Alcohol Engineered CementitiousComposite (PVA-ECC)[J]. ACI Materials Journal, 2001,98(6): 483-492[7]MAESHALL D B, COX B N and EVANS A G. The Mechan-ics of Matrix Cracking in Brittle Matrix Fiber Composites[J].ACTA Metallurgical, 1985, 33(11): 2 013-2 021[8]WANG S and LI V C. Tailoring of Pre-Existing Flaw inECC Matrix for Saturated Strain Hardening[C]. Proceed-ings of the Fifth International Conference on FractureMechanics of Concrete and Concrete Structures. Colorado:Ia-FraMCos, 2004: 1 005-1 012[9]Li V C, WU H C, and CHAN Y W. Interfacial PropertyTailoring for Pseudo Strain-Hardening Cementitious Composites[C]. Advanced Technology on Design and Fabrication of Composite Materials and Structures. Neth-erlands: Kluwer Acad. Publ., 1995: 261-268[10]SUN W, MANDEL J A and SAID Samir. Studies of theProperties of the Fiber-Matrix Interface in Steel Fiber Re-inforced Mortar[J]. ACI Materials Journal, 1987, 84(12):101-109[11]AKERS S A S. Long Term Durability of PVA ReinforcingFibers in a Cement Matrix[J]. The International Journal ofCement Composite and Lightweight Concrete, 1989, 11:79-91[12]KANDA T and LI V C. Interface Property and ApparentStrength of High-Strength Hydrophilic Fiber in CementMatrix[J]. Journal of Materials in Civil Engineering, 1998,10(1): 5-13[13]LI V C and WANG S. Process for Increasing the Ductilityof High Performance Fiber-Reinforced Brittle Matrix Composites and Composites Produced Thereby[P]. US Patent 7169224. 2007-01-30[14]REDON C. Measuring and Modifying Interface Propertiesof PVA Fibers in ECC Matrix[J]. ASCE J. Materials inCivil Engineering, 2001, 13(6): 399-406[15]CHEN H SUN W and PIET S. Interfacial Transition ZoneBetween Aggregate and Paste in Cementitious Composites(II): Mechanism of Formation and Degradation of Interfa-cial Transition Zone Microstructure and Its Influence Factors[J].Journal of the Cement Ceramic Society, 2004, 32(1): 70-80 [16]CHAN Y W and LI V C. Age Effect on the Characteristicsof Fibre/Cement Interfacial Properties[J]. Journal of Ma-terials Science, 1997, 32: 5 287-5 292[17]WANG S and LI V C. Engineered Cementitious Compos-ites with High-Volume Fly Ash[J]. ACI Materials Journal,2007, 104(3): 233-241。

外文翻译--创业板市场

外文文献翻译译文一、外文原文原文：China's Second BoardI. Significance of and events leading to the establishment of a Second BoardOn 31 March 2009 the China Securities Regulatory Commission (CSRC issued Interim Measures on the Administration of Initial Public Offerings and Listings of Shares on the ChiNext [i.e., the Second Board, also called the Growth Enterprise Market] ("Interim Measures"), which came into force on 1 May 2009. This marked the creation by the Shenzhen Stock Exchange of the long-awaited market for venture businesses. As the original plan to establish such a market in 2001 had come to nothing when the dotcom bubble burst, the market's final opening came after a delay of nearly 10 years.Ever since the 1980s, when the Chinese government began to foster the development of science and technology, venture capital has been seen in China as a means of supporting the development of high-tech companies financially. The aim, as can be seen from the name of the 1996 Law of the People's Republic of China on Promoting the Conversion of Scientific and Technological Findings into Productivity ,was to support the commercialization of scientific and technological developments. Venture capital funds developed gradually in the late 1990s, and between then and 2000 it looked increasingly likely that a Second Board would be established. When the CSRC published a draft plan for this in September 2000, the stage was set. However, when the dotcom bubble (and especially the NASDAQ bubble) burst, this plan was shelved. Also, Chinese investors and venture capitalists were probably not quite ready for such a move.As a result, Chinese venture businesses sought to list on overseas markets (a so-called "red chip listing") from the late 1990s. However, as these listings increased, so did the criticism that valuable Chinese assets were being siphoned overseas.On thepolicy front, in 2004 the State Council published Some Opinions on Reform, Opening and Steady Growth of Capital Markets ("the Nine Opinions"), in which the concept of a "multi-tier capital market" was presented for the first time. A first step in this direction was made in the same year, when an SME Board was established as part of the Main Board. Although there appear to have been plans to eventually relax the SME Board's listing requirements, which were the same as those for companies listed on the Main Board, and to make it a market especially for venture businesses, it was decided to establish a separate market (the Second Board) for this purpose and to learn from the experience of the SME Board.As well as being part of the process of creating a multi-tier capital market, the establishment of the Second Board was one of the measures included in the policy document Several Opinions of the General Office of the State Council on Providing Financing Support for Economic Development ("the 30 Financial Measures"), published in December 2008 in response to the global financial crisis and intended as a way of making it easier for SMEs to raise capital.It goes without saying that the creation of the Second Board was also an important development in that it gives private equity funds the opportunity to exit their investments. The absence of such an exit had been a disincentive to such investment, with most funds looking for a red chip listing as a way of exiting their investments. However, with surplus savings at home, the Chinese authorities began to encourage companies to raise capital on the domestic market rather than overseas. This led, in September 2006, to a rule making it more difficult for Chinese venture businesses to list their shares on overseas markets. The corollary of this was that it increased the need for a means whereby Chinese private equity funds could exit their investments at an early opportunity and on their own market. The creation of the Second Board was therefore a belated response to this need.II. Rules and regulations governing the establishment of the Second BoardWe now take a closer look at some of the rules and regulations governing the establishment of the Second Board.First , the Interim Measures on the Administration of Initial Public Offerings andListings of Shares on the ChiNext, issued by the CSRC on 31 March 2009 with effect from 1 May 2009. The Interim Measures consist of six chapters and 58 articles, stipulating issue terms and procedures, disclosure requirements, regulatory procedures, and legal responsibilities.First, the General Provisions chapter. The first thing this says (Article 1) is: "These Measures are formulated for the purposes of promoting the development of innovative enterprises and other growing start-ups" This shows that one of the main listing criteria is a company's technological innovativeness and growth potential. The Chinese authorities have actually made it clear that, although the Second Board and the SME Board are both intended for SMEs of similar sizes, the Second Board is specifically intended for SMEs at the initial (rather than the growth or mature) stage of their development with a high degree of technological innovativeness and an innovative business model while the SME Board is specifically intended for companies with relatively stable earnings at the mature stage of their development. They have also made it clear that the Second Board is not simply a "small SME Board." This suggests to us that the authorities want to see technologically innovative companies listing on the Second Board and SMEs in traditional sectors listing on the SME Board.Next, Article 7 says: "A market access system that is commensurate with the risk tolerance of investors shall be established for investors on the ChiNext and investment risk shall be fully disclosed to investors." One noteworthy feature is the adoption of the concept of the "qualified investor" in an attempt to improve risk control.Furthermore, Article 8 says: "China Securities Regulatory Commission (hereinafter, CSRC) shall, in accordance with law, examine and approve the issuer’s IPO application and supervise the issuer’s IPO activities. The stock exchange shall formulate rules in accordance with law, provide an open, fair and equitable market environment and ensure the normal operation of the ChiNext." Until the Second Board was established, it was thought by some that the stock exchange had the right to approve new issues. Under the Interim Measures, however, it is the CSRC that examines and approves applications.First, offering conditions. Article 10 stipulates four numerical conditions for companies applying for IPOs.Second, offering procedures. The Interim Measures seek to make sponsoring securities companies more responsible by requiring them to conduct due diligence investigations and make prudential judgment on the issuer’s growth and render special opinions thereon.Third, information disclosure. Article 39 of the Interim Measures stipulates that the issuer shall make a statement in its prospectus pointing out the risks of investing in Second Board companies: namely, inconsistent performance, high operational risk, and the risk of delisting. Similarly,Fourth, supervision. Articles 51 and 52 stipulate that the stock exchange (namely, the Shenzhen Stock Exchange) shall establish systems for listing, trading and delisting Second Board stocks, urge sponsors to fulfill their ongoing supervisory obligations, and establish a market risk warning system and an investor education system.1. Amendments to the Interim Measures on Securities Issuance and Listing Sponsor System and the Provisional Measures of the Public Offering Review Committee of the China Securities Regulatory Commission2. Rules Governing the Listing of Shares on the ChiNext of Shenzhen Stock Exchange Next, the Shenzhen Stock Exchange published Rules Governing the Listing of Shares on the ChiNext of Shenzhen Stock Exchange on 6 June (with effect from 1 July).3. Checking investor eligibility As the companies listed on the Second Board are more risky than those listed on the Main Board and are subject to more rigorous delisting rules (see above), investor protection requires that checks be made on whether Second Board shares are suitable for all those wishing to invest in them.4. Rules governing (1) application documents for listings on the ChiNext and (2) prospectuses of ChiNext companies On 20 July the CSRC published rules governing Application Documents for Initial Public Offerings and Listings of Shares on the ChiNext and Prospectuses of ChiNext Companies, and announced that it would begin processing listing applications on 26 July.III. Future developmentsAs Its purpose is to "promote the development of innovative enterprises and other growing start-ups"，the Second Board enables such companies to raise capital by issuing shares. That is why its listing requirements are less demanding than those of the Main Board but also why it has various provisions to mitigate risk. For one thing, the Second Board has its own public offering review committee to check how technologically specialized applicant companies are, reflecting the importance attached to this. For another, issuers and their controlling shareholders, de facto controllers, and sponsoring securities companies are subject to more demanding accountability requirements. The key factor here is, not surprisingly, disclosure. Also, the qualified investor system is designed to mitigate the risks to retail investors.Once the rules and regulations governing the Second Board were published, the CSRC began to process listing applications from 26 July 2009. It has been reported that 108 companies initially applied. As of mid-October, 28 of these had been approved and on 30 October they were listed on the Second Board.As of 15 December, there are 46 companies whose listing application has been approved by CSRC (including the above-mentioned 28 companies). They come from a wide range of sectors, especially information technology, services, and biopharmacy. Thus far, few companies in which foreign private equity funds have a stake have applied. This is because these funds have tended to go for red-chip listings.Another point is movement between the various tiers of China's multi-tier capital market. As of early September, four companies that are traded on the new Third Board had successfully applied to list on the Second Board. As 22 new Third Board companies meet the listing requirements of the Second Board on the basis of their interim reports for the first half of fiscal 2009, a growing number of companies may transfer their listing from the new Third Board to the Second Board. We think this is likely to make the new Third Board a more attractive market for private equity investors.The applicants include companies that were in the process of applying for a listing on the SME Board. The CSRC has also made it clear that it does not see theSecond Board simply as a "small SME Board" and attaches great importance to the companies' innovativeness and growth potential. Ultimately, whether or not such risks can be mitigated will depend on whether the quality of the companies that list on the Second Board improves and disclosure requirements are strictly complied with. For example, according to the rules governing Prospectuses of ChiNext Companies, companies are required to disclose the above-mentioned supplementary agreements as a control right risk. The point is whether such requirements will be complied with.Since there is a potentially large number of high-tech companies in China in the long term, whether or not the Second Board becomes one of the world's few successful venture capital markets will depend on whether all these rules and regulations succeed in shaping its development and the way in which it is run.The authorities clearly want to avoid a situation where the Second Board attracts a large number of second-rate companies and becomes a vehicle for market abuse as it would then run the risk of becoming an illiquid market shunned by investors who have lost trust in it. Indeed, such has been the number of companies applying to list on the Second Board that some observers have expressed concern about their quality.There has also been some concern about investor protection. For example, supplementary agreements between private equity funds and issuers pose a risk to retail investors in that they may suddenly be faced with a change in the controlling shareholder. This is because such agreements can result in a transfer of shares from the founder or controlling shareholder to a private equity fund if the company fails to meet certain agreed targets or in a shareholding structure that is different from the apparent one, for example. The problem of low liquidity, which has long faced the new Third Board market, where small-cap high-tech stocks are also traded, also needs to be addressed.Meanwhile, the Second Board's Public Offering Review Committee was officially established on 14 August. It has 35 members. A breakdown reveals that the number of representatives of the CSRC and the Shenzhen Stock Exchange has been limited to three and two, respectively, to ensure that the committee has the necessary number of technology specialists. Of the remainder, 14 are accountants, six lawyers,three from the Ministry of Science and Technology, three from the China Academy of Sciences, two from investment trust companies, one from an asset evaluation agency, and one from the National Development and Reform Commission (NDRC). It has been reported that the members include specialists in the six industry fields the CSRC considers particularly important for Second Board companies (namely, new energy, new materials, biotechnology and pharmaceuticals, energy conservation and environmental protection, services and IT).Source: Takeshi Jingu.2009.“China's Second Board”. Nomura Journal of Capital Markets Winter 2009 V ol.1 No.4.pp.1-15.二、翻译文章译文：中国创业板市场一、建立创业板市场及其意义2009年3月31日中国证券监督管理委员会(以下简称“中国证监会”)发行《中国证监会管理暂行办法》，首次在创业板市场上[即,第二个板,也叫创业板市场](“暂行办法”) 公开募股，从 2009年的5月1日开始生效，这标志着深圳证券交易所市场这个人们期待已久的合资企业即将诞生。

毕业论文外文翻译范例

外文原文(一)Savigny and his Anglo-American Disciple s*M. H. HoeflichFriedrich Carl von Savigny, nobleman, law reformer, champion of the revived German professoriate, and founder of the Historical School of jurisprudence, not only helped to revolutionize the study of law and legal institutions in Germany and in other civil law countries, but also exercised a profound influence on many of the most creative jurists and legal scholars in England and the United States. Nevertheless, tracing the influence of an individual is always a difficult task. It is especially difficult as regards Savigny and the approach to law and legal sources propounded by the Historical School. This difficulty arises, in part, because Savigny was not alone in adopting this approach. Hugo, for instance, espoused quite similar ideas in Germany; George Long echoed many of these concepts in England during the 1850s, and, of course, Sir Henry Sumner Maine also espoused many of these same concepts central to historical jurisprudence in England in the 1860s and 1870s. Thus, when one looks at the doctrinal writings of British and American jurists and legal scholars in the period before 1875, it is often impossible to say with any certainty that a particular idea which sounds very much the sort of thing that might, indeed, have been derived from Savigny's works, was, in fact, so derived. It is possible, nevertheless, to trace much of the influence of Savigny and his legal writings in the United States and in Great Britain during this period with some certainty because so great was his fame and so great was the respect accorded to his published work that explicit references to him and to his work abound in the doctrinal writing of this period, as well as in actual law cases in the courts. Thus, Max Gutzwiller, in his classic study Der einfluss Savignys auf die Entwicklung des International privatrechts, was able to show how Savigny's ideas on conflict of laws influenced such English and American scholars as Story, Phillimore, Burge, and Dicey. Similarly, Andreas Schwarz, in his "Einflusse Deutscher Zivilistik im Auslande," briefly sketched Savigny's influence upon John Austin, Frederick Pollock, and James Bryce. In this article I wish to examine Savigny's influence over a broader spectrum and to draw a picture of his general fame and reputation both in Britain and in the United States as the leading Romanist, legal historian, and German legal academic of his day. The picture of this Anglo-American respect accorded to Savigny and the historical school of jurisprudence which emerges from these sources is fascinating. It sheds light not only upon Savigny’s trans-channel, trans-Atlantic fame, but also upon the extraordinarily*M.H.Hoeflich, Savigny and his Anglo-American Disciples, American Journal of Comparative Law, vol.37, No.1, 1989.cosmopolitan outlook of many of the leading American and English jurists of the time. Of course, when one sets out to trace the influence of a particular individual and his work, it is necessary to demonstrate, if possible, precisely how knowledge of the man and his work was transmitted. In the case of Savigny and his work on Roman law and ideas of historical jurisprudence, there were three principal modes of transmission. First, there was the direct influence he exercised through his contacts with American lawyers and scholars. Second, there was the influence he exercised through his books. Third, there was the influence he exerted indirectly through intermediate scholars and their works. Let us examine each mode separately.I.INFLUENCE OF THE TRANSLATED WORKSWhile American and British interest in German legal scholarship was high in the antebellum period, the number of American and English jurists who could read German fluently was relatively low. Even those who borrowed from the Germans, for instance, Joseph Story, most often had to depend upon translations. It is thus quite important that Savigny’s works were amongst the most frequently translated into English, both in the United States and in Great Britain. His most influential early work, the Vom Beruf unserer Zeitfur Rechtsgeschichte und Gestzgebung, was translated into English by Abraham Hayward and published in London in 1831. Two years earlier the first volume of his History of Roman Law in the Middle Ages was translated by Cathcart and published in Edinburgh. In 1830, as well, a French translation was published at Paris. Sir Erskine Perry's translation of Savigny's Treatise on Possession was published in London in 1848. This was followed by Archibald Brown's epitome of the treatise on possession in 1872 and Rattigan's translation of the second volume of the System as Jural Relations or the Law of Persons in 1884. Guthrie published a translation of the seventh volume of the System as Private International Law at Edinburgh in 1869. Indeed, two English translations were even published in the far flung corners of the British Raj. A translation of the first volume of the System was published by William Holloway at Madras in 1867 and the volume on possession was translated by Kelleher and published at Calcutta in 1888. Thus, the determined English-speaking scholar had ample access to Savigny's works throughout the nineteenth century.Equally important for the dissemination of Savigny's ideas were those books and articles published in English that explained and analyzed his works. A number of these must have played an important role in this process. One of the earliest of these is John Reddie's Historical Notices of the Roman law and of the Progress of its Study in Germany, published at Edinburgh in 1826. Reddie was a noted Scots jurist and held the Gottingen J.U.D. The book, significantly, is dedicated to Gustav Hugo. It is of that genre known as an external history of Roman law-not so much a history of substantive Roman legal doctrine but rather a historyof Roman legal institutions and of the study of Roman law from antiquity through the nineteenth century. It is very much a polemic for the study of Roman law and for the Historical School. It imparts to the reader the excitement of Savigny and his followers about the study of law historically and it is clear that no reader of the work could possibly be left unmoved. It is, in short, the first work of public relations in English on behalf of Savigny and his ideas.Having mentioned Reddie's promotion of Savigny and the Historical School, it is important to understand the level of excitement with which things Roman and especially Roman law were greeted during this period. Many of the finest American jurists were attracted-to use Peter Stein's term-to Roman and Civil law, but attracted in a way that, at times, seems to have been more enthusiastic than intellectual. Similarly, Roman and Civil law excited much interest in Great Britain, as illustrated by the distinctly Roman influence to be found in the work of John Austin. The attraction of Roman and Civil law can be illustrated and best understood, perhaps, in the context of the publicity and excitement in the English-speaking world surrounding the discovery of the only complete manuscript of the classical Roman jurist Gaius' Institutes in Italy in 1816 by the ancient historian and German consul at Rome, B.G. Niebuhr. Niebuhr, the greatest ancient historian of his time, turned to Savigny for help with the Gaius manuscript (indeed, it was Savigny who recognized the manuscript for what it was) and, almost immediately, the books and journals-not just law journals by any means-were filled with accounts of the discovery, its importance to legal historical studies, and, of course, what it said. For instance, the second volume of the American Jurist contains a long article on the civil law by the scholarly Boston lawyer and classicist, John Pickering. The first quarter of the article is a gushing account of the discovery and first publication of the Gaius manuscript and a paean to Niebuhr and Savigny for their role in this. Similarly, in an article published in the London Law Magazine in 1829 on the civil law, the author contemptuously refers to a certain professor who continued to tell his students that the text of Gaius' Institutes was lost for all time. What could better show his ignorance of all things legal and literary than to be unaware of Niebuhr's great discovery?Another example of this reaction to the discovery of the Gaius palimpsest is to be found in David Irving's Introduction to the Study of the Civil Law. This volume is also more a history of Roman legal scholarship and sources than a study of substantive Roman law. Its pages are filled with references to Savigny's Geschichte and its approach clearly reflects the influence of the Historical School. Indeed, Irving speaks of Savigny's work as "one of the most remarkable productions of the age." He must have been truly impressed with German scholarship and must also have been able to convince the Faculty of Advocates, forwhom he was librarian, of the worth of German scholarship, for in 1820 the Faculty sent him to Gottingen so that he might study their law libraries. Irving devotes several pages of his elementary textbook on Roman law to the praise of the "remarkable" discovery of the Gaius palimpsest. He traces the discovery of the text by Niebuhr and Savigny in language that would have befitted an adventure tale. He elaborates on the various labors required to produce a new edition of the text and was particularly impressed by the use of a then new chemical process to make the under text of the palimpsest visible. He speaks of the reception of the new text as being greeted with "ardor and exultation" strong words for those who spend their lives amidst the "musty tomes" of the Roman law.This excitement over the Verona Gaius is really rather strange. Much of the substance of the Gaius text was already known to legal historians and civil lawyers from its incorporation into Justinian's Institutes and so, from a substantive legal perspective, the find was not crucial. The Gaius did provide new information on Roman procedural rules and it did also provide additional information for those scholars attempting to reconstruct pre-Justinianic Roman law. Nevertheless, these contributions alone seem hardly able to justify the excitement the discovery caused. Instead, I think that the Verona Gaius discovery simply hit a chord in the literary and legal community much the same as did the discovery of the Rosetta Stone or of Schliemann’s Troy. Here was a monument of a great civilization brought newly to light and able to be read for the first time in millenia. And just as the Rosetta Stone helped to establish the modern discipline of Egyptology and Schliemann's discoveries assured the development of classical archaeology as a modern academic discipline, the discovery of the Verona Gaius added to the attraction Roman law held for scholars and for lawyers, even amongst those who were not Romanists by profession. Ancillary to this, the discovery and publication of the Gaius manuscript also added to the fame of the two principals involved in the discovery, Niebuhr and Savigny. What this meant in the English-speaking world is that even those who could not or did not wish to read Savigny's technical works knew of him as one of the discoverers of the Gaius text. This fame itself may well have helped in spreading Savigny's legal and philosophical ideas, for, I would suggest, the Gaius "connection" may well have disposed people to read other of Savigny's writings, unconnected to the Gaius, because they were already familiar with his name.Another example of an English-speaking promoter of Savigny is Luther Stearns Cushing, a noted Boston lawyer who lectured on Roman law at the Harvard Law School in 1848-49 and again in 1851- 1852.Cushing published his lectures at Boston in 1854 under the title An Introduction to the Study of Roman Law. He devoted a full chapter to a description of the historical school and to the controversy betweenSavigny and Thibaut over codification. While Cushing attempted to portray fairly the arguments of both sides, he left no doubt as to his preference for Savigny's approach:The labors of the historical school have established an entirely new and distinct era in the study of the Roman jurisprudence; and though these writers cannot be said to have thrown their predecessors into the shade, it seems to be generally admitted, that almost every branch of the Roman law has received some important modification at their hands, and that a knowledge of their writings, to some extent, at least, is essentially necessary to its acquisition.译文(一)萨维尼和他的英美信徒们*M·H·豪弗里奇弗雷德里奇·卡尔·冯·萨维尼出身贵族，是一位出色的法律改革家，也是一位倡导重建德国教授协会的拥护者，还是历史法学派的创建人之一。

毕业论文文献外文翻译----危机管理：预防,诊断和干预文献翻译-中英文文献对照翻译

第1页共19页中文3572字毕业论文（设计）外文翻译标题：危机管理-预防，诊断和干预一、外文原文标题：标题：Crisis management: prevention, diagnosis and Crisis management: prevention, diagnosis andintervention 原文：原文：The Thepremise of this paper is that crises can be managed much more effectively if the company prepares for them. Therefore, the paper shall review some recent crises, theway they were dealt with, and what can be learned from them. Later, we shall deal with the anatomy of a crisis by looking at some symptoms, and lastly discuss the stages of a crisis andrecommend methods for prevention and intervention. Crisis acknowledgmentAlthough many business leaders will acknowledge thatcrises are a given for virtually every business firm, many of these firms do not take productive steps to address crisis situations. As one survey of Chief Executive officers of Fortune 500 companies discovered, 85 percent said that a crisisin business is inevitable, but only 50 percent of these had taken any productive action in preparing a crisis plan(Augustine, 1995). Companies generally go to great lengths to plan their financial growth and success. But when it comes to crisis management, they often fail to think and prepare for those eventualities that may lead to a company’s total failure.Safety violations, plants in need of repairs, union contracts, management succession, and choosing a brand name, etc. can become crises for which many companies fail to be prepared untilit is too late.The tendency, in general, is to look at the company as a perpetual entity that requires plans for growth. Ignoring the probabilities of disaster is not going to eliminate or delay their occurrences. Strategic planning without inclusion ofcrisis management is like sustaining life without guaranteeinglife. One reason so many companies fail to take steps to proactively plan for crisis events, is that they fail to acknowledge the possibility of a disaster occurring. Like an ostrich with its head in the sand, they simply choose to ignorethe situation, with the hope that by not talking about it, it will not come to pass. Hal Walker, a management consultant, points out “that decisions will be more rational and better received, and the crisis will be of shorter duration, forcompanies who prepare a proactive crisis plan” (Maynard, 1993) .It is said that “there are two kinds of crises: those that thatyou manage, and those that manage you” (Augustine, 1995). Proactive planning helps managers to control and resolve a crisis. Ignoring the possibility of a crisis, on the other hand,could lead to the crisis taking a life of its own. In 1979, theThree-Mile Island nuclear power plant experienced a crisis whenwarning signals indicated nuclear reactors were at risk of a meltdown. The system was equipped with a hundred or more different alarms and they all went off. But for those who shouldhave taken the necessary steps to resolve the situation, therewere no planned instructions as to what should be done first. Hence, the crisis was not acknowledged in the beginning and itbecame a chronic event.In June 1997, Nike faced a crisis for which they had no existi existing frame of reference. A new design on the company’s ng frame of reference. A new design on the company’s Summer Hoop line of basketball shoes - with the word air writtenin flaming letters - had sparked a protest by Muslims, who complained the logo resembled the Arabic word for Allah, or God.The council of American-Islamic Relations threatened aa globalNike boycott. Nike apologized, recalled 38,000 pairs of shoes,and discontinued the line (Brindley, 1997). To create the brand,Nike had spent a considerable amount of time and money, but hadnever put together a general framework or policy to deal with such controversies. To their dismay, and financial loss, Nike officials had no choice but to react to the crisis. This incident has definitely signaled to the company that spending a little more time would have prevented the crisis. Nonetheless,it has taught the company a lesson in strategic crisis management planning.In a business organization, symptoms or signals can alert the strategic planners or executives of an eminent crisis. Slipping market share, losing strategic synergy anddiminishing productivity per man hour, as well as trends, issues and developments in the socio-economic, political and competitive environments, can signal crises, the effects of which can be very detrimental. After all, business failures and bankruptcies are not intended. They do not usually happen overnight. They occur more because of the lack of attention to symptoms than any other factor.Stages of a crisisMost crises do not occur suddenly. The signals can usuallybe picked up and the symptoms checked as they emerge. A company determined to address these issues realizes that the real challenge is not just to recognize crises, but to recognize themin a timely fashion (Darling et al., 1996). A crisis can consistof four different and distinct stages (Fink, 1986). The phasesare: prodromal crisis stage, acute crisis stage, chronic crisisstage and crisis resolution stage.Modern organizations are often called “organic” due tothe fact that they are not immune from the elements of their surrounding environments. Very much like a living organism, organizations can be affected by environmental factors both positively and negatively. But today’s successfulorganizations are characterized by the ability to adapt by recognizing important environmental factors, analyzing them, evaluating the impacts and reacting to them. The art of strategic planning (as it relates to crisis management)involves all of the above activities. The right strategy, in general, provides for preventive measures, and treatment or resolution efforts both proactively and reactively. It wouldbe quite appropriate to examine the first three stages of acrisis before taking up the treatment, resolution or intervention stage.Prodromal crisis stageIn the field of medicine, a prodrome is a symptom of the onset of a disease. It gives a warning signal. In business organizations, the warning lights are always blinking. No matter how successful the organization, a number of issues andtrends may concern the business if proper and timely attentionis paid to them. For example, in 1995, Baring Bank, a UK financial institution which had been in existence since 1763,ample opportunitysuddenly and unexpectedly failed. There wasfor the bank to catch the signals that something bad was on thehorizon, but the company’s efforts to detect that were thwarted by an internal structure that allowed a single employee both to conduct and to oversee his own investment trades, and the breakdown of management oversight and internalcontrol systems (Mitroff et al., 1996). Likewise, looking in retrospect, McDonald’s fast food chain was given the prodromalsymptoms before the elderly lady sued them for the spilling ofa very hot cup of coffee on her lap - an event that resulted in a substantial financial loss and tarnished image of thecompany. Numerous consumers had complained about thetemperature of the coffee. The warning light was on, but the company did not pay attention. It would have been much simplerto pick up the signal, or to check the symptom, than facing the consequences.In another case, Jack in the Box, a fast food chain, had several customers suffer intestinal distress after eating at their restaurants. The prodromal symptom was there, but the company took evasive action. Their initial approach was to lookaround for someone to blame. The lack of attention, the evasiveness and the carelessness angered all the constituent groups, including their customers. The unfortunate deaths thatptoms,occurred as a result of the company’s ignoring thesymand the financial losses that followed, caused the company to realize that it would have been easier to manage the crisis directly in the prodromal stage rather than trying to shift theblame.Acute crisis stageA prodromal stage may be oblique and hard to detect. The examples given above, are obvious prodromal, but no action wasWebster’s New Collegiate Dictionary, an acute stage occursacutewhen a symptom “demands urgent attention.” Whether the acutesymptom emerges suddenly or is a transformation of a prodromalstage, an immediate action is required. Diverting funds and other resources to this emerging situation may cause disequilibrium and disturbance in the whole system. It is onlythose organizations that have already prepared a framework forthese crises that can sustain their normal operations. For example, the US public roads and bridges have for a long time reflected a prodromal stage of crisis awareness by showing cracks and occasionally a collapse. It is perhaps in light of the obsessive decision to balance the Federal budget that reacting to the problem has been delayed and ignored. This situation has entered an acute stage and at the time of this writing, it was reported that a bridge in Maryland had just collapsed.The reason why prodromes are so important to catch is thatit is much easier to manage a crisis in this stage. In the caseof most crises, it is much easier and more reliable to take careof the problem before it becomes acute, before it erupts and causes possible complications (Darling et al., 1996). In andamage. However, the losses are incurred. Intel, the largest producer of computer chips in the USA, had to pay an expensiveprice for initially refusing to recall computer chips that proved unreliable o n on certain calculations. The f irmfirm attempted to play the issue down and later learned its lesson. At an acutestage, when accusations were made that the Pentium Chips were not as fast as they claimed, Intel quickly admitted the problem,apologized for it, and set about fixing it (Mitroff et al., 1996). Chronic crisis stageDuring this stage, the symptoms are quite evident and always present. I t isIt is a period of “make or break.” Being the third stage, chronic problems may prompt the company’s management to once and for all do something about the situation. It may be the beginning of recovery for some firms, and a deathknell for others. For example, the Chrysler Corporation was only marginallysuccessful throughout the 1970s. It was not, however, until the company was nearly bankrupt that amanagement shake-out occurred. The drawback at the chronic stage is that, like in a human patient, the company may get used to “quick fixes” and “band “band--aid”approaches. After all, the ailment, the problem and the crisis have become an integral partoverwhelmed by prodromal and acute problems that no time or attention is paid to the chronic problems, or the managers perceive the situation to be tolerable, thus putting the crisison a back burner.Crisis resolutionCrises could be detected at various stages of their development. Since the existing symptoms may be related todifferent problems or crises, there is a great possibility thatthey may be misinterpreted. Therefore, the people in charge maybelieve they have resolved the problem. However, in practicethe symptom is often neglected. In such situations, the symptomwill offer another chance for resolution when it becomes acute,thereby demanding urgent care. Studies indicate that today anincreasing number of companies are issue-oriented and searchfor symptoms. Nevertheless, the lack of experience in resolvinga situation and/or inappropriate handling of a crisis can leadto a chronic stage. Of course, there is this last opportunityto resolve the crisis at the chronic stage. No attempt to resolve the crisis, or improper resolution, can lead to grim consequences that will ultimately plague the organization or even destroy it.It must be noted that an unsolved crisis may not destroy the company. But, its weakening effects can ripple through the organization and create a host of other complications.Preventive effortsThe heart of the resolution of a crisis is in the preventiveefforts the company has initiated. This step, similar to a humanbody, is actually the least expensive, but quite often the mostoverlooked. Preventive measures deal with sensing potential problems (Gonzales-Herrero and Pratt, 1995). Major internalfunctions of a company such as finance, production, procurement, operations, marketing and human resources are sensitive to thesocio-economic, political-legal, competitive, technological, demographic, global and ethical factors of the external environment. What is imminently more sensible and much more manageable, is to identify the processes necessary forassessing and dealing with future crises as they arise (Jacksonand Schantz, 1993). At the core of this process are appropriate information systems, planning procedures, anddecision-making techniques. A soundly-based information system will scan the environment, gather appropriate data, interpret this data into opportunities and challenges, and provide a concretefoundation for strategies that could function as much to avoid crises as to intervene and resolve them.Preventive efforts, as stated before, require preparations before any crisis symptoms set in. Generally strategic forecasting, contingency planning, issues analysis, and scenario analysis help to provide a framework that could be used in avoiding and encountering crises.出处：出处：Toby TobyJ. Kash and John R. Darling . Crisis management: prevention, diagnosis 179-186二、翻译文章标题：危机管理：预防，诊断和干预译文：本文的前提是，如果该公司做好准备得话，危机可以更有效地进行管理。

英文翻译附原文

本科毕业设计(论文) 外文翻译（附外文原文）系 ( 院 )：资源与环境工程系课题名称：英文翻译专业(方向)：环境工程班级：2004-1班学生：3040106119指导教师：刘辉利副教授日期：2008年4月20使用褐煤（一种低成本吸附剂）从酸性矿物废水中去除和回收金属离子a. 美国, 大学公园, PA 16802, 宾夕法尼亚州立大学, 能源部和Geo 环境工程学.b. 印度第80号邮箱, Mahatma Gandhi ・Marg, Lucknow 226001, 工业毒素学研究中心, 环境化学分部,于2006 年5月6 日网上获得，2006 年4月24 日接受，2006 年3月19 日;校正，2006 年2月15 日接收。

摘要酸性矿物废水(AMD), 是一个长期的重大环境问题，起因于钢硫铁矿的微生物在水和空气氧化作用, 买得起包含毒性金属离子的一种酸性解答。

这项研究的主要宗旨是通过使用褐煤（一种低成本吸附剂）从酸性矿水(AMD)中去除和回收金属离子。

褐煤已被用于酸性矿水排水AMD 的处理。

经研究其能吸附亚铁, 铁, 锰、锌和钙在multi-component 含水系统中。

研究通过在不同的酸碱度里进行以找出最适宜的酸碱度。

模拟工业条件进行酸性矿物废水处理, 所有研究被进行通过单一的并且设定多专栏流动模式。

空的床接触时间(EBCT) 模型被使用为了使吸附剂用量减到最小。

金属离子的回收并且吸附剂的再生成功地达到了使用0.1 M 硝酸不用分解塔器。

关键词:吸附; 重金属; 吸附; 褐煤; 酸性矿物废水处理; 固体废料再利用; 亚铁; 铁; 锰。

文章概述1. 介绍2. 材料和方法2.1. 化学制品、材料和设备3. 吸附步骤3.1. 酸碱度最佳化3.2. 固定床研究3.2.1 单一栏3.2.2 多栏4. 结果和讨论4.1. ZPC 和渗析特征4.2 酸碱度的影响4.3. Multi-component 固定吸附床4.3.1 褐煤使用率4.4. 吸附机制4.5. 解吸附作用研究5. 结论1. 介绍酸性矿物废水(AMD) 是一个严重的环境问题起因于硫化物矿物风化, 譬如硫铁矿(FeS2) 和它的同素异形体矿物(α-FeS) 。

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204/JOURNAL OF BRIDGE ENGINEERING/AUGUST1999JOURNAL OF BRIDGE ENGINEERING /AUGUST 1999/205ends.The stress state in each cylindrical strip was determined from the total potential energy of a nonlinear arch model using the Rayleigh-Ritz method.It was emphasized that the membrane stresses in the com-pression region of the curved models were less than those predicted by linear theory and that there was an accompanying increase in ﬂange resultant force.The maximum web bending stress was shown to occur at 0.20h from the compression ﬂange for the simple support stiffness condition and 0.24h for the ﬁxed condition,where h is the height of the analytical panel.It was noted that 0.20h would be the optimum position for longitudinal stiffeners in curved girders,which is the same as for straight girders based on stability requirements.From the ﬁxed condition cases it was determined that there was no signiﬁcant change in the membrane stresses (from free to ﬁxed)but that there was a signiﬁcant effect on the web bend-ing stresses.Numerical results were generated for the reduc-tion in effective moment required to produce initial yield in the ﬂanges based on curvature and web slenderness for a panel aspect ratio of 1.0and a web-to-ﬂange area ratio of 2.0.From the results,a maximum reduction of about 13%was noted for a /R =0.167and about 8%for a /R =0.10(h /t w =150),both of which would correspond to extreme curvature,where a is the length of the analytical panel (modeling the distance be-tween transverse stiffeners)and R is the radius of curvature.To apply the parametric results to developing design criteria for practical curved girders,the deﬂections and web bending stresses that would occur for girders with a curvature corre-sponding to the initial imperfection out-of-ﬂatness limit of D /120was used.It was noted that,for a panel with an aspect ratio of 1.0,this would correspond to a curvature of a /R =0.067.The values of moment reduction using this approach were compared with those presented by Basler (Basler and Thurlimann 1961;Vincent 1969).Numerical results based on this limit were generated,and the following web-slenderness requirement was derived:2D 36,500aa =1Ϫ8.6ϩ34(1)ͫͩͪͬt RRF w ͙ywhere D =unsupported distance between ﬂanges;and F y =yield stress in psi.An extension of this work was published a year later,when Culver et al.(1973)checked the accuracy of the isolated elas-tically supported cylindrical strips by treating the panel as a unit two-way shell rather than as individual strips.The ﬂange/web boundaries were modeled as ﬁxed,and the boundaries at the transverse stiffeners were modeled as ﬁxed and simple.Longitudinal stiffeners were modeled with moments of inertias as multiples of the AASHO (Standard 1969)values for straight ing analytical results obtained for the slenderness required to limit the plate bending stresses in the curved panel to those of a ﬂat panel with the maximum allowed out-of-ﬂatness (a /R =0.067)and with D /t w =330,the following equa-tion was developed for curved plate girder web slenderness with one longitudinal stiffener:D 46,000a a=1Ϫ2.9ϩ2.2(2)ͫͱͬt R f Rw ͙bwhere the calculated bending stress,f b ,is in psi.It was furtherconcluded that if longitudinal stiffeners are located in both the tension and compression regions,the reduction in D /t w will not be required.For the case of two stiffeners,web bending in both regions is reduced and the web slenderness could be de-signed as a straight girder panel.Eq.(1)is currently used in the ‘‘Load Factor Design’’portion of the Guide Speciﬁcations ,and (2)is used in the ‘‘Allowable Stress Design’’portion for girders stiffened with one longitudinal stiffener.This work wascontinued by Mariani et al.(1973),where the optimum trans-verse stiffener rigidity was determined analytically.During almost the same time,Abdel-Sayed (1973)studied the prebuckling and elastic buckling behavior of curved web panels and proposed approximate conservative equations for estimating the critical load under pure normal loading (stress),pure shear,and combined normal and shear loading.The linear theory of shells was used.The panel was simply supported along all four edges with no torsional rigidity of the ﬂanges provided.The transverse stiffeners were therefore assumed to be rigid in their directions (no strains could be developed along the edges of the panels).The Galerkin method was used to solve the governing differential equations,and minimum eigenvalues of the critical load were calculated and presented for a wide range of loading conditions (bedding,shear,and combined),aspect ratios,and curvatures.For all cases,it was demonstrated that the critical load is higher for curved panels over the comparable ﬂat panel and increases with an increase in curvature.In 1980,Daniels et al.summarized the Lehigh University ﬁve-year experimental research program on the fatigue behav-ior of horizontally curved bridges and concluded that the slen-derness limits suggested by Culver were too severe.Equations for ‘‘Load Factor Design’’and for ‘‘Allowable Stress Design’’were developed (respectively)asD 36,500a =1Ϫ4Յ192(3)ͫͬt R F w ͙y D 23,000a =1Ϫ4Յ170(4)ͫͬt Rf w ͙bThe latter equation is currently used in the ‘‘Allowable Stress Design’’portion of the Guide Speciﬁcations for girders not stiffened longitudinally.Numerous analytical and experimental works on the subject have also been published by Japanese researchers since the end of the CURT project.Mikami and colleagues presented work in Japanese journals (Mikami et al.1980;Mikami and Furunishi 1981)and later in the ASCE Journal of Engineering Mechanics (Mikami and Furunishi 1984)on the nonlinear be-havior of cylindrical web panels under bending and combined bending and shear.They analyzed the cylindrical panels based on Washizu’s (1975)nonlinear theory of shells.The governing nonlinear differential equations were solved numerically by the ﬁnite-difference method.Simple support boundary condi-tions were assumed along the curved boundaries (top and bot-tom at the ﬂange locations)and both simple and ﬁxed support conditions were used at the straight (vertical)boundaries.The large displacement behavior was demonstrated by Mi-kami and Furunishi for a range of geometric properties.Nu-merical values of the load,deﬂection,membrane stress,bend-ing stress,and torsional stress were obtained,but no equations for design use were presented.Signiﬁcant conclusions include that:(1)the compressive membrane stress in the circumfer-ential direction decreases with an increase in curvature;(2)the panel under combined bending and shear exhibits a lower level of the circumferential membrane stress as compared with the panel under pure bending,and as a result,the bending moment carried by the web panel is reduced;and (3)the plate bending stress under combined bending and shear is larger than that under pure bending.No formulations or recommendations for direct design use were made.Kuranishi and Hiwatashi (1981,1983)used the ﬁnite-ele-ment method to demonstrate the elastic ﬁnite displacement be-havior of curved I-girder webs under bending using models with and without ﬂange rigidities.Rotation was not allowed (ﬁxed condition)about the vertical axis at the ends of the panel (transverse stiffener locations).Again,the nonlinear distribu-206/JOURNAL OF BRIDGE ENGINEERING /AUGUST1999FIG. parison of Web Slenderness Requirements from AASHTO Guide Speciﬁcations and Nakaition of the membrane stress was noted but appears signiﬁcant only for extreme curvature and slenderness.Based on this non-linear membrane stress distribution,an effective web height was demonstrated.Also,the reduction in bending moment re-sistance was demonstrated,but,for slenderness in the design range,only a small reduction was noted.No formulations or recommendations for direct design use were made.Fujii and Ohmura (1985)presented research on the nonlin-ear behavior of curved webs using the ﬁnite-element method.Models included simple support,ﬁxed support,and ﬂange ri-gidities at the ﬂange/web boundaries.The large displacement behavior was demonstrated for loads beyond the elastic bifur-cation load.Also,the nonlinear membrane stress distribution was demonstrated,but the effect on resistance moment or ﬂange stress increase was not mentioned.It was emphasized that the web panel model with no ﬂange rigidity is inadequate in estimating the behavior of the curved panel under signiﬁcant loading.No direct recommendations or formulations regarding the design of curved I-girder webs were made.Suetake et al.(1986)examined the inﬂuence of ﬂanges on the strength of curved I-girders under bending using the mixed ﬁnite-element approach.The ends of the panels (transverse stiffener locations)were modeled as simple supports,and var-ious width/thickness ratios for the ﬂanges were modeled.Ge-ometric nonlinear analyses were conducted.Conclusions in-cluded that the aspect ratio of the panel was of minor importance and that the inﬂuence of the ﬂange rigidity cannot be ignored.Also,observations were made on the torsional buckling behavior of the ﬂanges.No quantitative formulations for design use were recommended.Nakai et al.(1986)conducted analytical research on the elastic large displacement behavior of curved web plates sub-jected to bending using the ﬁnite-element method.The web plate panels were modeled with and without stiffnesses for the ﬂanges.Models without ﬂange rigidity were modeled as ﬁxed and simple supports.The boundary conditions at the panel ends (transverse stiffener locations)were modeled as simple support.One and two levels of longitudinal stiffeners were also modeled.It was determined that inclusion of the ﬂange stiffnesses is essential to extract reliable results for the behav-ior of the curved web panels;therefore,all parametric results provided are from the use of the ﬂange-rigidity models.It was further shown that increasing curvature has little ef-fect on the resisting moment (less that 10%within the range of actual bridge parameters).This was attributed to the fact that the web contributes only a small portion to the resistance moment,as compared with the ﬂanges.It was also demon-strated that the maximum web deﬂection occurs in the vicinity of 0.25D from the compression ﬂange but that this transverse deﬂection is effectively eliminated when one or two longitu-dinal stiffeners are present.The effect of curvature on the plate bending stresses was also demonstrated with respect to the effect of the slenderness ratio (D /t w )and cur-vature (a /R ).Web slenderness requirements were formulated by Nakai and Yoo (1988)based on the effects of curvature on displace-ment and stress and proposed for adoption by the Hanshin Guidelines for the Design of Horizontally Curved Girder Bridges (Kitada et al.1986).It was suggested that limiting values should be established so that the curved web platetransverse deﬂection,and plate bending stress,c c␦,␴,max max would be limited to the maximum transverse deﬂection and bending stress that would occur in the straight girder with the same dimensions but,instead of curvature,with a maximum initial deﬂection,w 0,of D /250,which is the maximum allow-able initial deﬂection stipulated in the Japanese design code (Speciﬁcations 1990a,b).From a comparison of the displace-ment results with the stress results,it was shown that criteriabased on the stress requirement would result in a more con-servative design.A regression analysis was performed,and (5)–(7)resulted (Guidelines 1988;Nakai and Yoo 1988).Also,analytical investigations on the effects of longitudinal stiffen-ers resulted in a proposal for the design rigidity of the stiff-eners:D ␤0Յ(5)t wa 1ϩ␣0ͩͪRfor the case of no longitudinal stiffenersDՅ␤(6)0t wfor the case of one or two longitudinal stiffeners and a /R Յ␩0;and2Da a Յ␤␥Ϫ␦ϩε(7)000ͫͩͪͩͪͬt RRwfor the case of one or two longitudinal stiffeners and a /R >␩0.A plot of (5)–(7)along with the current Guide Speciﬁca-tions requirements is presented in Fig.1,in which extreme disparity in the reduction due to curvature can be noted for the design of girders with longitudinal stiffeners.The portion of the design equations that represent the effects of curvature can be separated for comparison as2aa R =1Ϫ8.6ϩ34(8)C 1ͫͩͪͬRRJOURNAL OF BRIDGE ENGINEERING /AUGUST 1999/207FIG. parison of Curvature Reduction Equations—No Longitudinal Stiffenersa aR =1Ϫ2.9ϩ2.2(9)C 2ͫͱͬR R aR =1Ϫ4(10)D ͫͬR1R =(11)N 1a ͫͬ1ϩ␣0ͩͪR 2a a R =␥Ϫ␦ϩε(12)N 200ͫͩͪͩͪͬRREq.(8)refers to the reduction on design D /t by Culver as shown in (1);(9)refers to the reduction by Culver as shown in (2);(10)refers to the reduction by Daniels as shown in (3)and (4);(11)refers to the reduction by Nakai as shown in (5);and (12)refers to the reduction by Nakai as shown in (7).Fig.2com-bines the available reduction factors (R C 1,R D ,R N 1)on design D /t w for girders without longitudinal stiffeners.The reduction equations for design of girders with longitudinal stiffeners (R C 2and R N 2)will be demonstrated in a subsequent paper.Nakai and coresearchers conducted other research pertaining to the behavior of curved I-girder webs,including a series of experimental research on the behavior of the curved I-girder web under bending,shear,and combined bending and shear (Nakai et al.1983,1984a–c,1985a,b).In 1983,Nakai et al.presented the results from eight experimental test specimens under pure bending with slenderness ratios of D /t w =178with no longitudinal stiffeners and one specimen with a longitudinal stiffener and a D /t w =250.Panel aspect ratios of 0.5and 1.0and radii of curvature of 10and 30m were used.It was ver-iﬁed that the ideal buckling phenomenon does not occur in the curved panels,but rather that the out-of-plane displacement of the web plate gradually increases in accordance with applied bending moment.But even so,it was noted that a critical bend-ing moment could be clearly observed.A recent investigation by Frank and Helwig (1995)using elastic buckling ﬁnite-element analyses of ﬂat panels resulted in suggested design equations for determining the buckling capacity of webs when the neutral axis varies during the var-ious stages of loading.Panels with and without longitudinal stiffeners were considered.GENERAL METHODOLOGYTo understand the behavior of the curved web and to de-velop predictor equations,a combined approach was used in-volving:(1)a theoretical development to derive equations thatapproximate the linear behavior of the system;and (2)the ﬁnite-element method to verify the applicability of the theo-retical equations and to investigate the elastic buckling and geometric nonlinear behaviors.This paper focuses on the the-oretical development and veriﬁcation.In a subsequent paper,strength reduction equations are formulated and proposed as a possible starting point in developing equations for the design of curved plate girder webs.RESULTSParametric ReviewA parametric analysis was conducted to summarize the nu-merical range of parameters used in current designs and pre-vious numerical and experimental research by others.Many of the earlier investigations on the subject were conducted using exaggerated cross-section parameters and curvatures (not to mention loading and boundary conditions),which resulted in exaggerated and unrealistic results.Due to publication length restrictions,not all of the results can be presented here,but they can be found in the dissertation ‘‘Nominal Bending and Shear Strength of Horizontally Curved Steel I-Girder Bridges,’’by Davidson (1996).The dimensions presented in the parametric summaries include those used in the current analyses along with a brief selection extracted from a variety of sources representing actual designs (AISC 1992,1993a–d),design examples (‘‘V-load’’1984;Yadlosky 1993),planned tests as part of the FHWA Curved Steel Bridge Research Pro-ject,and tests [as summarized by Hall and Yoo (1996)]per-formed by Culver and coresearchers (Mozer et al.1975a,b),Daniels et al.(1979a,b),Fukumoto and Nishida (1981),and Nakai et al.(1983,1984a).Curved Web BehaviorTo begin the investigation,the behavior of single web pan-els of various aspect ratios,curvatures,and cross-section di-mensions was analyzed using the ﬁnite-element method (MSC/NASTRAN 1994).In general,the dimensions used in the models follow the dimensions described in Table 1.The boundary conditions at the ends of the panels (transverse stiff-ener locations)were modeled as both simple and ﬁxed sup-ports,and those at the top and bottom of the panel were mod-eled as simple,ﬁxed,and with ﬂange rigidity included.In general,though,boundary conditions were used that would provide the most conservative results (maximum transverse displacement or maximum stress)with respect to developing criteria for design.Loading was applied at end node points to simulate bending moment.As an example of the resulting lin-ear-elastic behavior,consider the curved panel model de-scribed in Fig.3with a radius of curvature of R =30.5m (100ft),web height of h =2,032mm (80in.),panel aspect ratio a /h =2.0,thickness of t w =10.16mm (0.4in.),and ﬂange rigidity matching that of a 30.48ϫ609.6mm (1.2ϫ24in.)ﬂange.The displacement of the doubly symmetric cross sec-tion at a /2is shown in Fig.4.Note that the rotation direction of the ﬂange is opposite that assumed by linear torsion theory and also note the ‘‘bulging’’out displacement of the web.This ‘‘bulging’’displacement will obviously result in plate bending stresses with respect to both the vertical (z )and circumferential (␪)directions,which would not occur in the ﬂat panel under pure vertical bending moment.Also,the radius of curvature was varied for several sections,and the membrane stresses at the lengthwise center of the panel (a /2)were analyzed.From Fig.5,it can be noted that,as curvature (and panel slenderness h /t w )is increased,the membrane stress distribution becomes increasing nonlinear through the depth of the section.This has been noted by other208/JOURNAL OF BRIDGE ENGINEERING /AUGUST 1999TABLE1.Critical Stress Comparison—Curved versusStraightCRITICAL STRESS RATIO (CURVED/STRAIGHT)h =80in.;b f =24in.h /t (1)a /h (2)Critical Stress (ksi)Theoretical (k =36.5)(3)Finite-element result (4)R =1,000ft t f /t w =3(5)t f /t w =5(6)R =500ft t f /t w =3(7)t f /t w =5(8)R =100ftt f /t w =3(9)t f /t w =5(10)10010010020020020030030030012312312395.6795.6795.6723.9223.9223.9210.6310.6310.63101.78101.58101.4925.4825.4225.4011.3411.3211.311.0011.0021.0031.0031.0061.0071.0061.0111.0141.0141.0151.0171.0161.0191.0201.0191.0241.0261.0031.0061.0101.0101.0211.0301.0221.0711.0571.0161.0191.0241.0241.0331.0401.0361.0751.0631.0681.1381.1691.2901.2971.3381.4281.4461.5001.0811.1321.1831.2931.2951.3391.4301.4431.498Note:1in.=25.4mm;1ft =0.305m;1ksi =6.895MPa.FIG. 3.Finite-Element Model DescriptionFIG. 5.Membrane Stress Distribution through Panel Depth with Increase in Curvature and Increase in h /t wFIG. 4.Displacement of Cross Sectionresearchers,as described above.As a result of this reduction in web membrane stress,the ﬂanges carry a higher load;thus,even without considering warping stresses in the ﬂanges,the curved section would be unable to carry as much vertical moment as the comparable straight section before yielding of the ﬂanges initiates.However,for the most severe case considered here [h /t w =200,R =30.5m (100ft),a /h =3.0],the increase in ﬂange normal stress resultant is less than 6%based on the linear anal-ysis.This seems reasonable,since,for this section,the web contributes less than 18%of the total moment of inertia.Also of interest is the location of the absolute maximum stresses,since,in the design of the curved I-girder webs,it is desired to limit the maximum stress below a certain allowable stress,generally based on the yield stress.Because the mem-brane stress dominates,the maximum combined stresses in the panel occur at the top of the panel at the ﬂange/web intersec-tion,as it would for ﬂat panels (Davidson 1996).Lateral Pressure AnalogyThe amount of transverse or ‘‘bulging’’displacement can be approximated by using a ‘‘lateral pressure’’analogy.Con-JOURNAL OF BRIDGE ENGINEERING /AUGUST 1999/209FIG.7.Theoretical Development for Flat Panel under Hydro-static LoadingFIG. 6.Lateral Pressure Analogy Developmentsider a virtual width strip,dh ,of the curved web panel of thickness t and radius R under vertical bending stress,as shown in Fig.6.The resultant force,P ,due to vertical bending moment on the virtual strip of the panel is non-collinear.Be-cause of this non-collinearity,a lateral ‘‘virtual’’distributed load results along the unit strip,which,after considering that the radius is very large with respect to the panel length,can be viewed as a virtual pressure through the depth of the girderP ␴t q ==(13)c R RSince the distortion of the cross section results from an ap-plied vertical bending moment and the transverse displacement of the deformed cross section will cross the undeformed ver-tical axis at the neutral axis,the displacement behavior is anal-ogous to that of a ﬂat plate of length a ,thickness t ,and width h c ,simply supported on the bottom edge,with a linearly in-creasing transverse load,as shown in ing this anal-ogy,the displacements and plate bending moments can be readily solved for the fourth (ﬂange)edge of the plate as sim-ple and ﬁxed support,similar to the hydrostatic solutions pro-vided by Timoshenko and Woinowsky-Krieger (1959).For the ﬂat rectangular plate with two opposite edges simply sup-ported,Levy (1899)suggested taking the solution in the form of a series:ϱm ␲x w =Y sin(14)m ͸am =1where w =component of displacement in the transverse di-rection;and Y m =function of y only and must be in a form that satisﬁes the boundary conditions and the governing dif-ferential equation444Ѩw Ѩw Ѩw q q x0ϩ2ϩ==(15)4224Ѩx Ѩx Ѩy Ѩy D aD p pFurther simpliﬁcation can be made by taking the solution of(15)in the formw =w ϩw (16)12where w 1=particular solution to the deﬂection of a strip under a hydrostatic load represented as5q 3x 033w =Ϫ10ax ϩ7a x 1ͩͪ360D apϱ4m ϩ12q a (Ϫ1)m ␲x0=sin ͸55D ␲m ap m =1,3,5...(17)which satisﬁes the boundary conditions at x =0and x =a of2Ѩww =0,=0(18)2Ѩx and w 2represents the homogeneous solution to (15)and is of the form4q a m ␲y m ␲y m ␲y0w =A coshϩB sinh 2m m ͩD a a apm ␲y m ␲y m ␲y ϩC sinhϩD cosh m m ͪa a a(19)Noting that the last two terms of (19)are odd functions andthat the displacement of the plate about the x -axis must be symmetric due to symmetric boundary conditions,C m and D m must therefore be zero.The total solution is now of the formϱ4m ϩ1q a 2(Ϫ1)m ␲y0w =ϩA cosh m͸ͫ55D ␲m apm =1m ␲y m ␲y m ␲xϩB sinh sinmͬa aa(20)From the boundary conditions,the constants can be ob-tained asm ϩ1(2ϩ␣tanh ␣)(Ϫ1)m m A =Ϫ(21)m 55␲m cosh ␣mm ϩ1(Ϫ1)B =(22)m 55␲m cosh ␣mwherem ␲b ␣=(23)m 2aand,further noting that at y =0,sinh(␣m )equals zero and cosh(␣m )equals unity,(20)can be simpliﬁed toϱ4m ϩ1q a 2(Ϫ1)m ␲x 0(w )=ϩA sin(24)y =0m͸ͫͬ55D ␲m apm =1or in simpler terms4␣q a 0(w )=(25)y =0D pwhere210/JOURNAL OF BRIDGE ENGINEERING /AUGUST1999FIG.10.␤versus a /h c Plot for h /t w =200FIG.9.␣versus a /h c Plot for h /t w =200FIG.8.␣versus a /h c Plot for h /t w =100ϱm ϩ12(Ϫ1)m ␲x ␣=ϩA sin(26)m͸ͫͬ55␲m am =1and is a function of x and y and the plate aspect ratio only;and where3Et D =(27)p 212(1Ϫ␯)The plate bending moments M x and M y can be derived as22Ѩw ѨwM =ϪD ϩ␯(28)x p ͩͪ22Ѩx Ѩy 22Ѩw ѨwM =ϪD ϩ␯(29)y pͩͪ22Ѩy ѨxAfter substitution of (20),(28)and (29)can be most simply written as2(M )=␤q a (30)x y =0x 02(M )=␤q a (31)y y =0y 0where ␤x and ␤y result from the summation of terms similarly to ␣in (26)and,again,are functions of x and y and the plate aspect ratio only.This same procedure can be followed for the case of three simply supported edges and the fourth edge ﬁxed.For this case,the particular solution,w 1,is of the formq x04224w =(16y Ϫ24b y ϩ5b )(32)1384aD pwhich satisﬁes the differential equation (15)and the boundary conditions.Again,␣and ␤constants can be extracted.With respect to the lateral pressure analogy for the bending of the curved web panel,these boundary conditions were cho-sen to provide bounds with respect to the lateral displacements and stresses.For the maximum ‘‘bulging’’transverse displace-ment,the value of ␣is derived by considering the fourth (ﬂange)edge of the model as simple support.In reality,of course,the ﬂange will provide a torsional rigidity between that of ﬁxed and simple.For the maximum plate bending stress occurring at the top of the web (ﬂange/web juncture),the case where the fourth edge is ﬁxed will provide a conservative value of ␤.Following this approach,the maximum displace-ment and bending stress of the panel,respectively,can then be approximated by42␣h ␴12(1Ϫ␯)c m ␦=(33)max2Et R2␤h t ␴cmM =(34)b ␪Rwhere ␣and ␤are constants depending on the location of the displacement or moment,respectively,and the aspect ratio only;h c =height of the web in compression;and ␴m =stress at the web/ﬂange line resulting from vertical bending moment.Finite-element models were created to verify the applica-bility of the above formulation.Both ﬂat plate models and curved web models under stress due to the vertical bending moment were used for comparison.For the curved plate mod-els,the ␣and ␤results are averaged for various curvatures (Davidson 1996).The ﬂange/web edge was modeled as sim-ple,ﬁxed,and with various ﬂange rigidities.Figs.8–10clearly demonstrate that the lateral pressure analogy closely models the linear elastic displacement behavior of the curved web panel,within reasonable limits of curvature.From Figs.8–10,it can be noted that the simple support and ﬁxed support at the top (ﬂange)boundary bound the values of ␣where ﬂangerigidities were included,up to an aspect ratio (in compression)a /h c =6.The values for the simple support condition converge to approximately ␣=0.00651with increasing aspect ratio (a /h c ).Similarly,the values of ␤with ﬂange rigidities are bounded by the ﬁxed case,and the ﬁxed-ﬂange values con-verge to ␤=0.0667.It should be noted though,that the lateral pressure analogy becomes less accurate for higher curvatures.This is because the analogy assumes a linear distribution of the membrane stress through the depth of the web in com-pression,which becomes less true for increasing curvatures. But,with regard to predicting the‘‘bulging’’displacement and the resulting plate bending stresses at theﬂange/web juncture for design,the inaccuracy is in the conservative direction,i.e., the nonlinear membrane stress distribution will cause the bulg-ing displacement and plate bending stresses predicted by the lateral load analogy to be greater than the actual.The accuracy and applicability of the approach with respect to curved I-girder web design,including deﬂection ampliﬁcation effects, will be demonstrated in a subsequent paper.Elastic Buckling BehaviorAs mentioned in the‘‘Background’’section,an extensive investigation on the bifurcation load for curved web panels under both bending and shear and their combinations was done as early as1973by Abdel-Sayed,but withoutﬂange rigidity included in the mathematical models.As veriﬁcation,eigen-values were extracted for the models described above.The critical stresses for the curved panels were normalized to that of theﬂat panel with the same dimensions and are presented in Table1.Also,the theoretical approximation shown as(35) is presented for reference purposes.Eq.(35)represents the approximate elastic buckling stress for theﬂat web panel with ﬂange rigidity and is the basis for the web design parameters used in current design speciﬁcations:2␲E␴Ϸ[0.8(kϪk)ϩk](35)crϪst fs ss ss2212(1Ϫ␯)(h/t)wwhere k fs and k ss represent the buckling constants for a plate under vertical bending stresses withﬁxed-simple and simple-simple boundary conditions,respectively.From the results pre-sented in Table1,it can be noted that the critical loads of the panels with curvature are indeed higher than theﬂat panels. The buckled modeshapes for theﬂat panel and the curved are practically identical(Ballance1996).Because this veriﬁes that the elastic buckling critical stresses of the curved panels are greater than that of the comparableﬂat,no further effort will be given to the eigenvalue analysis.SUMMARY AND CONCLUSIONSAlthough a number of researchers(mostly Japanese)have investigated the behavior of horizontally curved I-girder webs, very little useful design information has been presented.The current web slenderness requirements presented in the AASHTO Guide Speciﬁcations for Horizontally Curved High-way Bridges are based upon analytical research by Culver that was conducted as part of the CURT project and upon experi-mental research by Daniels in the1970s.The only other known formulations for curved web slenderness requirements are those suggested by the Japanese researcher Nakai.The reductions in required web slenderness for all of these for-mulations,though,represent regression curves of analytical data where the curvature of the panel,a/R,is the only param-eter affecting the design.There is great disparity between the reduction presented by Culver and that presented by Nakai. Furthermore,the research on which these reduction equations were based involved only doubly symmetric sections and lim-ited panel aspect ratios.It is doubtful that engineers using these design equations are aware of these limitations.The present research takes a more methodical and theory-based approach.A‘‘lateral pressure’’analogy is developed, and it is shown that this analytical model can be conservatively applied to approximate the‘‘bulging’’transverse displace-ments and plate bending stresses.This model will subse-quently be enhanced to include nonlinear effects and to de-velop equations that represent the reduction in strength due to curvature.ACKNOWLEDGMENTSThe research presented here was conducted at Auburn University and is supported as part of the Federal Highway Administration Contract No. DTFH61-92-C-00136Curved Steel Bridge Research Project.Auburn Uni-versity is a subcontractor to HDR Engineering,Inc.,who is the prime contractor for this project.The opinions and conclusions expressed or implied in the paper are those of the writers and are not necessarily those of the Federal Highway Administration.APPENDIX I.REFERENCESAbdel-Sayed,G.(1973).‘‘Curved webs under combined shear and nor-mal stresses.’’J.Struct.Div.,ASCE,99(3),511–525.AISC Marketing,Inc.(1992).‘‘Bridges,a preliminary design study: Ramp B,Okeechobee Rd.to SB S.R.826,Dade County Florida.’’PDS 92/043,Chicago.AISC Marketing,Inc.(1993a).‘‘Bridges,a preliminary design study:Fly-over Ramp DB,Charlotte,North Carolina.’’PDS93/005,Chicago. AISC Marketing,Inc.(1993b).‘‘Bridges,a preliminary design study:NH Rte.27over Rte.51,Hampton,New Hampshire.’’PDS92/067,Chi-cago.AISC Marketing,Inc.(1993c).‘‘Bridges,a preliminary design study: Ramp14,Florida Ave.Bridge over IHNC,Orleans Parish,Louisiana.’’PDS93/009,Chicago.AISC Marketing,Inc.(1993d).‘‘Bridges,a preliminary design study: Westbound ramp over Independence Boulevard Mecklenburg Co., North Carolina.’’PDS93/029,Chicago.Ballance,S.R.(1996).‘‘The behavior of horizontally curved I-girder webs under pure bending,’’MS thesis,Auburn University,Auburn,Ala. Basler,K.,and Thurliman,B.(1961).‘‘Strength of plate girders in bend-ing.’’J.Struct.Div.,ASCE,87(6),153–181.Brogan,D.(1972).‘‘Bending behavior of cylindrical web panels,’’MS thesis,Carnegie-Mellon University,Pittsburgh.Culver,C.G.(1972).‘‘Design recommendations for curved highway bridges.’’Project68-32,Commonwealth of Pennsylvania Department of Transportation,Harrisburg,Pa.Culver,C.G.,Dym,C.,and Brogan,D.(1972a).‘‘Bending behaviors of cylindrical web panels.’’J.Struct.Div.,ASCE,98(10),2201–2308. Culver,C.G.,Dym,C.,and Brogan,D.(1972b).‘‘Instability of horizon-tally curved members—bending behaviors of cylindrical web panels.’’Rep.Prepared for PENDOT,Carnegie-Mellon University,Pittsburgh. Culver,C.G.,Dym,C.L.,and Uddin,T.(1973).‘‘Web slenderness re-quirements for curved girders.’’J.Struct.Div.,ASCE,99(3),417–430. Daniels,J.H.,Zettlemoyer,N.,Abraham, D.,and Batcheler,R.P. (1979a).‘‘Fatigue of curved steel bridge elements—analysis and de-sign of plate girder and box girder test assemblies.’’DOT-FH-11-8198.1,Lehigh University,Bethlehem,Pa.Daniels,J.H.,Fisher,J.W.,Batcheler,R.P.,and Maurer,J.K.(1979b).‘‘Fatigue of curved steel bridge elements—ultimate strength tests of horizontally curved plate and box girders.’’DOT-FH-11-8198.7,Le-high University,Bethlehem,Pa.Daniels,J.H.,Fisher,J.W.,and Yen,B.T.(1980).‘‘Fatigue of curved steel bridge elements,design recommendations for fatigue of curved plate girder and box girder bridges.’’Rep.No.FHWA-RD-79-138,Of-ﬁces of Res.and Devel.Struct.and Appl.Mech.Div.,Federal Highway Administration,Washington,D.C.Davidson,J.S.(1996).‘‘Nominal bending and shear strength of curved steel I-girder bridge systems,’’PhD dissertation,Auburn University, Auburn,Ala.Frank,K.H.,and Helwig,T.A.(1995).‘‘Buckling of webs in unsym-metric plate girders.’’Engrg.J.,32(3),43–53.Fujii,K.,and Ohmura,H.(1985).‘‘Nonlinear behavior of curved girder web consideringﬂange rigidities.’’Proc.,JSCE,Struct.Engrg./Earth-quake Engrg.,Tokyo,2(1).Fukumoto,Y.,and Nishida,S.(1981).‘‘Ultimate load behavior of curved I-beams.’’J.Engrg.Mech.Div.,ASCE,107(2),367–385. 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