Influence of Temperature and Composition on the Linear Viscoelastic Properties of Synthetic Binders
全球变暖如何影响动物英语作文
全球变暖如何影响动物英语作文英文回答：Global warming poses significant threats to animal species worldwide. Rising temperatures, alteredprecipitation patterns, and more frequent and intense extreme weather events can have severe consequences for animal populations and their habitats.Physiological Impacts: Warmer temperatures can lead to heat stress, dehydration, and impaired thermoregulation in animals. This can reduce their ability to forage, reproduce, and survive in their natural environments. Some species may be forced to migrate to cooler areas or face extinction if they cannot adapt to the changing conditions.Habitat Loss and Degradation: Climate change can alter important habitats for animals. Rising sea levels andcoastal erosion can destroy coastal habitats, while changes in precipitation patterns can affect freshwateravailability and vegetation growth. These habitat disruptions can reduce food resources, shelter, and breeding grounds for animals, forcing them to compete for limited resources or relocate to new areas.Altered Food Sources: The availability and quality of food sources can be impacted by climate change. Changes in temperature and precipitation can affect plant growth and distribution, which in turn affects the abundance and nutritional value of food sources for animals. This can disrupt predator-prey relationships and lead to population declines in certain species.Disease Transmission: Climate change can also increase the risk of disease outbreaks in animals. Warmer temperatures and altered precipitation patterns can favor the spread of pathogens and parasites, leading to increased morbidity and mortality rates. This can further weaken animal populations and reduce their resilience to other threats.Species Distribution and Extinction Risk: Globalwarming can alter the geographic distribution of animal species. Some species may expand their range to cooler areas, while others may experience range contractions or become locally extinct. The loss of biodiversity can have cascading effects on ecosystems and threaten ecosystem services that are essential for human well-being.Mitigation and Adaptation Measures: Addressing the impacts of global warming on animals requires amultifaceted approach. Mitigation measures include reducing greenhouse gas emissions to stabilize global temperatures and slow down the rate of change. Adaptation measuresinclude implementing conservation strategies to protect animal habitats, enhance their resilience to climate change, and facilitate their migration to new areas if necessary.中文回答：气候变化对动物的影响。
The Effect of Temperature on Protein Conformation
The Effect of Temperature on ProteinConformationProteins are essential components of living organisms and are responsible for carrying out various cellular functions. They are composed of long chains of amino acids that are folded into intricate 3-dimensional structures. The specific shape of a protein, or its conformation, plays a critical role in its function. Temperature is one of the key factors that can influence protein conformation. In this article, we will explore the effect of temperature on protein conformation and how it impacts their function.Temperature-induced protein denaturationProtein denaturation is a process in which the protein loses its native conformation and unfolds into a linear or random coil structure. This process can be triggered by several factors, including pH, salts, mechanical stress, and temperature. Among these, temperature is the most commonly studied factor that can induce protein denaturation.When proteins are exposed to high temperatures, the thermal energy causes the bonds that hold the protein structure together to break. Hydrogen bonds, which are weaker than covalent bonds, are the first to be broken. As the temperature continues to rise, the more significant covalent bonds that hold the protein together begin to break, further destabilizing the structure. Ultimately, the protein loses its native conformation, and its function is impaired.The effect of temperature on protein stabilityThe stability of a protein refers to its ability to maintain its native conformation in the face of various environmental conditions, including temperature. The stability of a protein is influenced by several factors, including the amino acid sequence, solvent conditions, and the presence of ligands or cofactors. Temperature can disrupt the stability of a protein by altering its structure and causing it to denature.Proteins have a range of thermal stability that depends on their amino acid sequence and their specific structure. Generally, proteins that are stable at higher temperatures have a higher content of hydrophobic amino acids, which can help to stabilize the structure through hydrophobic interactions. In contrast, proteins that are stable at lower temperatures tend to have more polar amino acids and a lower content of hydrophobic amino acids.The temperature at which a protein denatures is known as its melting temperature or Tm. The Tm of a protein is influenced by its intrinsic stability as well as the specific conditions under which it is studied. For example, the pH, salt concentration, and presence of other molecules can all affect the Tm of a protein.The effect of temperature on protein functionThe specific conformation of a protein plays a critical role in its function. Therefore, changes in protein conformation due to temperature can have a significant impact on their function. The effect of temperature on protein function can vary depending on the specific protein and the conditions under which it is studied.Some proteins are more sensitive to changes in temperature than others. For example, enzymes, which catalyze chemical reactions in the cell, have a specific optimal temperature range at which they function best. Outside of this range, the reaction rate can slow down or even stop altogether due to changes in protein conformation.Other proteins, such as transporters and receptors, are also sensitive to changes in temperature. Changes in protein conformation due to temperature can affect the ability of these proteins to bind to their ligands and carry out their function.ConclusionIn conclusion, temperature has a significant impact on protein conformation. High temperatures can cause proteins to denature, while changes in temperature can alter their stability and affect their function. Understanding the effect of temperature on protein conformation and function is essential for designing experiments and developing new drugs and therapies that target specific proteins.。
温度对微孔发泡PP和HDPE材料冲击性能的影响 (1)
的一种新型的热塑性高分子材料。微孔发泡材 料具有密度低、 较高的冲击强度、 比强度、 抗疲 劳强度和热稳定性 等优异性能。大量实验 表 明, 微孔对聚合物材料的常温冲击性能常常起 增韧的作用 。 Waldman 在测量微孔发泡 PS 的冲击韧性时, 发现 其缺口 Charpy 冲击韧 性和落重冲击韧性结论相反。微孔对聚合物材 料冲击性能影响的研究通常在常温下测试, 缺 乏不同实验条件下变形断裂规律及机制的系统 研究 , 且微孔对聚合物材料冲击性能的影响也 存在矛盾的结论。本文以 PP、 HDPE 为对象 , 在较宽的温度范围内系统测试了不同实验温度 下微孔发泡和未发泡 PP 、 H DPE 的 Izod 缺口冲 击强度, 并结合冲击断口形貌特征系统观察, 研 究了实验温度对微孔发泡 PP、 H DPE 材料冲击 强度 及 断 裂 机 制 的 影 响, 为 微 孔 发 泡 PP、 HDPE 的研究和应用提供了理论依据。
大的影响, 微孔的引入又使温度对 Izod 缺口冲 击强度的影响关系出现了新的变化。从 Fig. 1 、 F ig. 2 中可以看出 , 微孔发泡 PP、 HDPE, 以及 对应未发泡 PP 、 H DPE 都随实验温度的降低其 Izod 缺 口 冲 击 强 度 值 下 降。 对 于 P P, 在 - 57 ~ 63 范围内 , 微发泡高于未发泡 P P 的 Izod 缺口冲击强度 , 随着温度的变化, 微发 泡和未发泡 PP 的 Izod 缺口冲击强度的变化趋 势相似。如果将未发泡 PP 的曲线整体向上移 动至与微发泡 PP 的直线部分重合 ( Fig. 1 中虚 线部分 ) , 则可得出 , 微发泡 P P 具有优越的低 温冲 击性 能; 有 较低 的韧 脆转 变温 度。 对于 HDPE, 实验温度范围内, 都在 - 53 度高于 - 35 存在 Izod 缺口冲击强度值随温度变化规律的突变 , 且温 , 微孔发泡 H DPE 的 Izod 缺口 后, 冲击强度比未发泡的低, 温度低于 - 35
混凝土材料英文名称
AbramsAbrams cone—Abrams 圆筒（坍落度筒）Abrams law—Abrams 定贝UAdmixture—外加剂宀化学外加剂Aggregate—骨料Absorptio n of water —吸水率Alkali-carb on ate reacti on —碱-碳酸盐反应Chloride—氯化物Clay—黏土comb in ati on of —结合criteria of accepta nee—接受准贝Ufrost resista nee—抗冻性gradi ng—级配Los An geles tes—洛杉矶实验Maximum size and water requireme nt—最大粒径和需水量Mecha ni cal properties—力学性能Moisture —含水率organic substa nee—有机杂质porosity —孔隙率sieve an alysis-筛分分析S.S.D—饱和面干sulphate —硫酸盐water requireme nt —需水量Aggressive CO2—侵蚀介质CO2Alite —xx 特Ammon ium salts—铵盐Amorphous silica—无定形二氧化硅ASR Alkali-silica-reaction in aggregat—骨料中的碱-硅反应: BBelite—贝利特Blast furn ace ceme n—矿渣水泥Bleedi ng—泌水con crete in floor —地板混凝土grout —水泥浆in flue nee of steel bond—钢筋粘结的影响in flue nee of tran siti on zone—过渡区的影响mortar —砂浆BolomeyCCapillary porosity—毛细管孔隙率Capillary pressure—毛细管压力Carb on ati on—碳化Characteristic stre ngth—特征强度Chemical admixtures 一化学外加剂Air entraining age nts(AEA—弓丨气剂use in shotcrete—在喷射混凝土中的应用ASR in hibitor—碱-硅反应抑制剂Corrosi on in hibitors —防腐剂Classification—分类Harde ning accelerators—促硬剂Hydrophobic admixtures—防水剂High-range water reducers superplasticizers-高效减水齐U （超塑化齐U）Retarders—缓凝剂Sett ing accelerators—促凝剂Use in shotcrete—用于喷射混凝土中Sila nes—硅烷Shrin kage-reduc ing admixtures—减缩剂SRA^ Shrin kagereduc ing admixturesSuperplasticizers—高效减水剂（超塑化剂）Mecha nism of acti on of—作用机理Slump loss/retention —坍落度损失/保持Multifunctional —多功能的Use in shotcrete—用于喷射混凝土中Use to increase strength/durability —用于提高强度/耐久性Use to reduce ceme n—用于减少水泥Use to in crease workability—用于提高工作性Viscosity modifyi ng age nts—黏度调节齐UVMA T> Viscosity modifyi ng age ntsWater-reducers—减水剂Ceme nt—水泥Norms —标准Set regulator —调凝剂Sett in g—凝结Stre ngth —强度Chloride—氯化物Diffusion —扩散Compactability —密实性Compact ing factor—密实系数Composite ceme nt—复合水泥Composite Portla nd ceme nt—复合硅酸盐水泥Con crete—混凝土Damage^ deteriorati on 损伤宀劣化DE—延迟钙矶石形成Degree of compaction—密实度In shotcrete —喷射混凝土Degree of con solidation—密实度Degree of hydratio n—水化程度Depassivation—去钝化Deteriorati on —劣化Drying shri nkage — shri nka干缩—攵缩DSP一致密小颗粒混凝土Durability —耐久性Capillary porosity—毛细管孔隙率Con crete cover—混凝土保护层Exposure classe—暴露等级Long term durability —长期耐久性Deteriorati on —劣化Manu facture —生产Placi ng—浇筑Prestressed—预应力Rei nforced—增强Corrosion of reinforcement —钢筋的腐蚀Promoted by carbonation —碳化引起Promoted by chloride —氯化物引起Cracki ng—开裂Creep—徐变Basic—基本Drying—干燥In flue nee of creep on drying shri nkage—徐变对干缩的影响Predicti on of creep in con crete structures—混凝土结构的徐变预测Cored con crete—混凝土芯样Curi ng—养护In flue nee of curing on durability —养护对耐久性的影响In flue nee of curi ng on con crete stren gth—养护对混凝土强度的影响Membra ne —薄膜Wet curi ng —湿养C3A—铝酸三钙C4AF—铁铝酸四钙C3S—硅酸三钙2S—硅酸二钙C-S-H—水化硅酸钙EEn trai ned air 一引气In flue nee on freez ing—对抗冻性的影响In flue nee on stren gth —对强度的影响En trapped air—夹杂气体Ettri ngite —钙矶石Primary—一次See on dary—二次Expansive agents — Shrinkage eompensating cone膨胀剂宀收—!补偿混凝土FFibre-i nforced con erete ( FRC—纤维增强混凝土Applieation of FRC—纤维增强混凝土的应用Craek-free con erete 一无裂缝混凝土Tough ness of con erete—混凝土的韧性Impact stre ngth —冲击强度In shotcrete —喷射混凝土Metallic fibre —金属纤维Polymer min i-fibre —聚合物微纤维Polymer macro-fibre—聚合物大纤维Polymer structure PVA fibres—聚合物结构聚乙烯醇纤维Fictitious thick ness—虚拟厚度Fire en dura nee of con crete 一混凝土的耐火性Behavior of concrete during fire 一混凝土在火中的行为Behavior of high-stre ngth con crete duri ng fire —高强混凝土在火中的行为In flue nee of the aggregate—骨料的影响In flue nee of the con crete cover—混凝土保护层的影响In flue nee of the metallic fibres 一金属纤维的影响In flue nee of the loadi ng in service 一服役荷载的影响In flue nee of the polymeric fibres —聚合物纤维的影响Fly ash—粉煤灰Ben eficiati on —选矿Freez ing and thaw ing—冻融F u llerF u ller&Thompson 宀F u llerGGGBFS> slag磨细粒化高炉矿渣—矿渣Gluco nate—葡萄糖酸盐Glucose—葡萄糖Grout—浆体Gypsum—石膏HHeat—热Crack ing due to thermal gradie nts—温度梯度诱发开裂Of hydration—水化热Hydratio n —水化Of alumi nates—铝酸盐的水化Of silicates—硅酸盐的水化High-Performa nee Con crete—高性能混凝土High Stre ngth Con crete—高强混凝土Hooke law—Hooke 定律KKiln 一烧窑LLeachi ng—析浆Lightweight con crete—轻混凝土Glassificatio n—分类Expa nded clay—陶粒Lightweight aggregate—轻骨料In the Rome Pa ntheor—罗马万神殿Natural lightweight aggregate(pumice)—天然轻骨料(浮石) Shrin kage—收缩Structural —结构的Precast L. C-预制轻混凝土SCC L.—自密实轻混凝土Structural L. C for ready-mixed con crete—预拌结构轻混凝土Lig nosulpho nate—木素磺酸盐Lime—石灰Limest one—石灰石Ble nded ceme nt —混合水泥Lyse rule—Lyse 准贝UMMagn esium salts—镁盐Mass con crete—大体积混凝土Mix desig n—配合比设计Modulus—模数Of elasticity—弹性模量Of fineness—细度模数Mill —磨机Mun icipal Solid Waste In ci nerator —市政固体废物焚烧炉PPassivation—钝化Permeability—渗透性Pop-out 一凸起Porosity—孔隙率Capillary—毛细管孔隙Capillary porosity and stre ngth—毛细管孔隙率与强度Capillary porosity and elastic modulus—毛细管孔隙率与弹性模量Capillary porosity and permeability—毛细管孔隙率与渗透性Capillary porosity and durability—毛细管孔隙率与耐久性Gel—凝胶Macroporosity —大孔孔隙率Portla nd ceme nt—硅酸盐水泥Ble nded ceme nts —混合水泥Europea n n orm—欧洲标准Ferric 一铁相Manu facture —生产White —白色Powers—能源Pozzola n—火山灰Activity —活性In dustrial —工业的Pozzola nic ceme nt—火山灰水泥Precast con crete—预制混凝土Steam curi ng—蒸养Prescripti ons on con crete structures—混凝土结构的质量要求Con crete compositi on prescriptio ns—混凝土组成的质量要求Con crete performa nee prescriptio ns—混凝土性能的质量要求Con tractor prescripti ons —对承包商的要求RReactive Powder Con cret厂活性粉末混凝土Recycled con crete一再生混凝土Process of manu facturi ng recycled aggregate (RA一再生骨料的^ 口工工艺Properties of RA 一再生骨料的性能Con tam inant products—污染物Den sity of RA—再生骨料的密度Water absorption —吸水率Properties of con crete with RA—含有再生骨料混凝土的性能Relaxation—松弛Retemperi ng—重拌合SSegregation—离析SCS SeHCompact ing Con Crete—自密实混凝土Self-Compacti ng Con Crete-自密实混凝土Architectural 一装饰High stre ngth—高强Mass con crete—大体积混凝土Lightweight con crete—轻混凝土Shrin kage-compe nsati ng—收缩补偿Setti ng—凝结Shrin kage—收缩Drying shri nkage—干缩In flue nee of aggregate on drying shri nkage —骨料对干缩的影响In flue nee of high range water reducers on dry ing shri nkage—高效减水剂对干缩的影响In flue nee of workability on dryi ng shri nkage 一工作性对干缩的影响Predictio n of drying shri nkage in con crete structures—混凝土结构干缩的预测Plastic shrin kage—塑性收缩Standard shr in kage—标准收缩Shrin kage-compe nsat ing con crete-收缩补偿混凝土Expa nsive age nt—膨胀齐UCombi ned use of SRA and expa nsive agen—减缩剂和膨胀剂的结合应用Lime-based expa nsive age nt—石灰基膨胀剂Sulphoalu min ate-based expa nsive age nt—硫铝酸盐基膨胀剂Applicati on of shri nkage compe nsat ing con crete—补偿收缩混凝土的应用Joi nt-free architectural build ings—无缝装饰建筑Joi nt-free in dustrial floor 一无缝工业地板Repair of damaged con crete structures—损坏混凝土结构的修补Expa nsion of specime n vs. that of structure—试件的膨胀与结构的膨胀Restra ined expa nsion—约束膨胀SCC shri nkage-compe nsat ing con cret—自密实收缩补偿混凝土Shotcrete—喷射混凝土ACI recomme ndatio ns—ACI 建议Bond of shotcrete. to substrate—喷射混凝土与基层的粘结Chemical admixtures in—喷射混凝土的化学外加剂Alkali-free accelerators—无碱促进齐USodium silicate accelerators—硅酸钠促进齐UComposition of 一喷射混凝土组成Fibres in—喷射混凝土的纤维High performa nee—高性能喷射混凝土TTemperature—温度In flue nee of temperature on con crete stre ngth —温度对强度的影响In flue nee of temperature on site orga ni zatio n —温度对现场浇筑的影响In flue nee of steel bars on—配筋的影响Mineral additi ons in —矿物掺合料Nozzelman喷枪操作工Rebou nd—回弹Sieve an alysis-筛分Silica fume—硅灰Silica fume in high stre ngth con crete—高强混凝土中的硅灰Slag—矿渣Ceme nt—矿渣水泥Slump—坍落度Slump loss—坍落度损失SRA^ Shrin kage Reduci ng Admixture in Chemical Admixture 一化学外加剂中的减缩剂Standard deviation 一标准差Steam curi ng—蒸养Steel-co ncrete bond—钢筋-混凝土的粘结Stre ngth —强度Characteristic 一特征强度Class of ceme n—水泥的强度等级Class of con crete一混凝土的强度等级Compressive—抗压强度DSP con crete—细颗粒密实混凝土Flexural—抗折强度High-stre ngth con crete—高强混凝土Influence of compaction on 一密实性对强度的影响In flue nee of ceme nt on con crete 一水泥对混凝土强度的影响Influence of temperature on concrete —温度对混凝土强度的影响In flue nee of tran sition zone on —过渡区对强度的影响Of ceme nt paste—水泥浆的强度Of cored samples 一芯样的强度Of specime ns—试件的强度Stan dard deviati on—标准差Te nsile—抗拉强度Stress—应力Compressive—压应力Flexural—弯曲应力Ten sile 一拉应力Sulphate attack—硫酸盐侵蚀Superplsticizer 宀Chemical. admixtu超塑化剂—高效减水剂）T化学外加剂Plac ing in summer time 一夏季浇筑Plac ing in win ter time 一冬季浇筑Thaumasite—硅灰石膏Thermal gradie nts—温度梯度Tran siti on zone—过渡区VVebe—维勃Vibratio n —振动WWater—水And workability —水与工作性And stre ngth. —水与强度Addition on job site 一水的现场添加Water-ceme nt ratio —水灰比Workability —工作性And con solidation —工作性与密实性《A Novel Cable-E nhan ced,Wire-MeshRe in forceme nt for Structural Con crete toImprove Its Properties》。
介绍温度句式英语作文
介绍温度句式英语作文Introduction to Temperature。
Temperature is a measure of the degree of hotness or coldness of an object. It is an important physical quantity that affects our daily lives. In this essay, we will explore the different types of temperature scales, the factors that affect temperature, and the applications of temperature in various fields.Types of Temperature Scales。
There are three main temperature scales used in the world today: Celsius, Fahrenheit, and Kelvin. The Celsius scale, also known as the centigrade scale, is based on the freezing and boiling points of water. The freezing point of water is 0 degrees Celsius (°C), and the boiling point is 100°C. The Fahrenheit scale, developed by the German physicist Daniel Gabriel Fahrenheit, is based on the freezing and boiling points of a mixture of salt, ice, andwater. The freezing point of this mixture is 32 degrees Fahrenheit (°F), and the boiling point is 212°F. The Kelvin scale, named after the British physicist William Thomson, is based on the absolute zero point, which is the temperature at which all matter has zero thermal energy. The Kelvin scale is used in scientific and engineering applications.Factors that Affect Temperature。
温度对半导体影响的书
温度对半导体影响的书英文回答：The effect of temperature on semiconductors is acrucial aspect to consider in the field of electronics. As temperature changes, it can have both positive and negative impacts on the performance and reliability of semiconductor devices.One of the main effects of temperature on semiconductors is the change in electrical conductivity. Generally, as temperature increases, the conductivity of a semiconductor also increases. This is due to the increased thermal energy, which allows more charge carriers to move freely within the material. As a result, the resistance of the semiconductor decreases, and it becomes more conductive.However, this positive effect of temperature on conductivity can also have negative consequences. For instance, if the temperature rises too high, it can lead tothermal runaway, where the increased conductivity causes excessive heating and further increases the temperature. This can ultimately result in the device failing or even burning out.Another important effect of temperature on semiconductors is the impact on bandgap energy. The bandgap energy is the energy difference between the valence band and the conduction band in a semiconductor. At higher temperatures, the bandgap energy decreases, which meansthat the semiconductor becomes more conductive and allows more charge carriers to move across the bandgap. This can affect the performance of devices such as diodes and transistors, as it can lead to increased leakage currents and reduced efficiency.Furthermore, temperature can also affect the mobility of charge carriers in semiconductors. Mobility refers to the ease with which charge carriers can move through the material. At higher temperatures, the mobility of both electrons and holes in a semiconductor generally increases. This can lead to improved device performance, as the chargecarriers can move more freely and quickly. However, at extremely high temperatures, the mobility can besignificantly reduced due to scattering effects, which can negatively impact device performance.In addition to these electrical effects, temperaturecan also affect the mechanical properties of semiconductors. For example, as the temperature changes, the coefficient of thermal expansion of the semiconductor material can cause stress and strain in the device. This can lead to mechanical failure or even cracking of the semiconductor.中文回答：温度对半导体的影响是电子领域中需要考虑的一个关键因素。
分析气温的英文作文
分析气温的英文作文英文：When it comes to the topic of temperature, there are many factors that can affect it. The first thing that comes to mind is the weather. Depending on the season, the temperature can be drastically different. For example, during the summer months, the temperature can reach up to 40 degrees Celsius, while during the winter months, it can drop to -10 degrees Celsius.Another factor that can affect temperature is location. Different regions have different climates, which can result in different temperatures. For instance, in tropical regions, the temperature can be consistently high, while in colder regions, the temperature can be consistently low.Additionally, human activity can also impact temperature. For example, urban areas tend to be warmer than rural areas due to the amount of concrete and asphaltthat absorb heat. On the other hand, forests and green spaces tend to be cooler due to the shade and moisture they provide.Overall, temperature is a complex topic that is influenced by many factors. It is important to understand these factors in order to properly prepare for and adapt to changes in temperature.中文：谈到气温这个话题，有很多因素会影响它。
怎样介绍温度英语作文
怎样介绍温度英语作文Title: Understanding Temperature: A Comprehensive Introduction。
Temperature is a fundamental aspect of our daily lives, influencing everything from the weather to the behavior of substances. In this essay, we will delve into the conceptof temperature, exploring its definition, measurement, effects, and significance in various contexts.Definition and Measurement:Temperature is defined as the degree of hotness or coldness of a body or environment. It is a measure of the average kinetic energy of the particles in a substance. The most common unit of temper ature is degrees Celsius (°C), although other units such as Fahrenheit (°F) and Kelvin (K) are also used.Temperature can be measured using various instruments,such as thermometers. Traditional liquid-in-glass thermometers, digital thermometers, and infrared thermometers are among the tools commonly employed to determine temperature accurately.Effects of Temperature:Temperature exerts significant influence on both living organisms and non-living systems. In living organisms, temperature plays a crucial role in biological processes. For instance, human body temperature must remain within a narrow range (approximately 36.5°C to 37.5°C) for optimal physiological functioning. Extreme deviations from this range can lead to health problems, such as hypothermia or hyperthermia.In non-living systems, temperature affects the physical properties of substances. For example, changes in temperature can cause solids to melt into liquids and liquids to vaporize into gases. This phenomenon is evident in everyday experiences, such as the melting of ice cream on a hot day or the boiling of water when heated.Significance in Various Contexts:1. Weather and Climate: Temperature plays a centralrole in determining weather conditions and climate patterns. It influences phenomena such as precipitation, wind patterns, and the formation of weather systems like hurricanes and tornadoes. Climatologists use temperature data to analyze long-term climate trends and predict future climate changes.2. Industry and Engineering: In industrial processes, temperature control is essential for ensuring the quality and efficiency of manufacturing operations. From food processing to semiconductor fabrication, precisetemperature regulation is vital for achieving desired outcomes and maintaining product integrity.3. Environmental Impact: Temperature variations have significant implications for the environment. Global warming, driven by increased atmospheric concentrations of greenhouse gases, has led to rising temperatures worldwide.This phenomenon has far-reaching consequences, includingthe melting of polar ice caps, sea-level rise, and changesin ecosystems and biodiversity.4. Medicine and Healthcare: Temperature monitoring is crucial in medical settings for diagnosing and treating various health conditions. Healthcare professionals use thermometers to measure body temperature and identify fever, a common symptom of infections and illnesses. Additionally, temperature-controlled environments are necessary forstoring medications, vaccines, and biological samples.Conclusion:In conclusion, temperature is a fundamental conceptwith widespread implications across diverse fields and disciplines. Whether influencing the weather, driving industrial processes, shaping environmental dynamics, or impacting human health, temperature exerts a profound influence on our lives. By understanding the principles of temperature and its effects, we can better navigate and adapt to the dynamic world around us.。
温度英语作文
温度英语作文Temperatures and Their ImpactTemperatures are a fundamental aspect of our daily lives, affecting everything from the clothes we wear to the activities we engage in. The range of temperatures we experience can have a significant impact on our physical and mental well-being, as well as on the natural world around us. In this essay, we will explore the various ways in which temperature can influence our lives and the world we live in.One of the most obvious ways in which temperature affects us is through the clothing we choose to wear. In colder climates, we must bundle up in warm layers to protect ourselves from the biting cold, while in warmer regions, lightweight and breathable fabrics are the order of the day. The ability to adapt our attire to the prevailing temperature is a testament to the ingenuity of the human species and our ability to thrive in a wide range of environmental conditions.Beyond the practical considerations of clothing, temperature can also have a profound impact on our physical health. Extreme heat or cold can put significant stress on the body, leading to a range of medicalconditions such as heat exhaustion, hypothermia, and even frostbite. In some cases, prolonged exposure to extreme temperatures can be life-threatening, highlighting the importance of being prepared and taking appropriate precautions.The impact of temperature is not limited to human health, however. The natural world is also highly sensitive to changes in temperature, with entire ecosystems and the species that inhabit them being affected. Shifts in temperature can lead to disruptions in the delicate balance of nature, causing species to migrate, adapt, or even become extinct. This is particularly evident in the case of climate change, where the gradual warming of the planet is leading to a host of environmental challenges that we must address.In addition to its physical impacts, temperature can also have a significant effect on our mental and emotional well-being. Many people find that their mood and energy levels are influenced by the prevailing temperature, with cold and gloomy weather often associated with feelings of sadness and lethargy, while warm and sunny days can lift our spirits and boost our motivation.This emotional connection to temperature is not just a personal quirk but is rooted in the way our brains and bodies respond to changes in the environment. For example, exposure to cold temperatures can trigger the release of hormones like cortisol, which can contribute tofeelings of stress and anxiety. Conversely, warm temperatures can stimulate the production of endorphins, which are associated with feelings of happiness and well-being.Given the multifaceted impact of temperature on our lives, it is clear that understanding and adapting to temperature variations is a crucial skill for navigating the world around us. Whether we are planning a vacation, choosing a career, or simply trying to make the most of our daily lives, being mindful of the role that temperature plays can help us make more informed and effective decisions.In conclusion, temperature is a powerful force that shapes our experiences and influences the world we live in. From the clothes we wear to the health of our planet, temperature is a constant presence that we must learn to understand and manage. By embracing the complexities of temperature and its impacts, we can better prepare ourselves for the challenges and opportunities that lie ahead.。
高温对人类的影响英语作文
高温对人类的影响英语作文The Impact of High Temperature on HumansIn recent years, the issue of high temperature and its effects on human beings has bee increasingly prominent. High temperatures can have a significant impact on our lives in various aspects.Firstly, high temperatures pose a direct threat to our physical health. Heat strokes and heat exhaustion are mon problems during hot weather. The elderly, children, and those with certn chronic diseases are particularly vulnerable. Prolonged exposure to high temperatures can lead to dehydration, fatigue, and in severe cases, organ flure and even death.Secondly, high temperatures affect our dly activities and work efficiency. It bees unfortable to carry out outdoor work or exercise, as the heat makes us feel drned and less energetic. This can have an adverse effect on productivity in many industries, such as construction and agriculture.Moreover, high temperatures also put a strn on the power supply. The increased use of r conditioning and other cooling devices leads to a surge in electricity demand, which may result in power shortages and blackouts.High temperatures also have an impact on our mental well-being. The hot and unfortable environment can cause irritability, stress, and sleep disturbances, affecting our mood and overall quality of life.To cope with the challenges brought high temperatures, we need to take various measures. This includes staying hydrated, avoiding prolonged exposure to the sun, wearing light and breathable clothing, and using proper cooling methods. At the same time, the government and society should also strengthen infrastructure building to improve the ability to deal with extreme temperatures and promote energy conservation and emission reduction to mitigate the effects of climate change.In conclusion, high temperatures have multiple negative impacts on human beings, and it is crucial for us to be aware of these effects and take active steps to protect ourselves and our munities.。
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Influence of Temperature and Composition on theLinear Viscoelastic Properties of Synthetic Binders Francisco Martı´nez-Boza,*Pedro Partal,Benjamı´n Conde,and Crı´spulo Gallegos Departamento de Ingenierı´a Quı´mica.Universidad de Huelva,Escuela Polite´cnica Superior, Ctra.de Palos de la Frontera s/n,21819,Huelva,SpainReceived April26,1999.Revised Manuscript Received September8,1999This paper deals with the influences that mineral oil,resin,and SBS triblock copolymer concentrations exert on the linear viscoelastic properties of these materials in a wide range of temperatures,with the overall objective of formulating pigmentable synthetic binders with adequate mechanical properties.The relationship between microstructure and linear viscoelastic properties is also studied.Three different regions,transition to glassy,plateau and beginning of the terminal region may be observed in the dynamic mechanical spectrum of these systems, depending on SBS concentration and temperature.Dynamic mechanical analysis tests confirm that the synthetic binders studied are not thermorheologically simple materials as a consequence of the formation of a multiphase system.A polymer-rich phase with high elastic properties and a resin-rich phase with predominant viscous characteristics were found.At high polymer concentration a continuous polymer-rich phase appears,while the continuous resin-rich phase is obtained at low polymer concentration or high resin content.IntroductionThe main use of bitumen is as a binder that,blended with mineral aggregates,makes asphalt,1a mix that is extensively used in road pavement.2,3The performance of a road pavement is controlled by the mechanical properties of the bitumen,due to the fact that it forms a continuous matrix and is the only deformable compo-nent.4-6Bitumen is the highly viscous residue of crude oil, obtained by removing most of its volatile components.7 The chemical composition of bitumen is very complex, although its components can be broadly categorized as maltenes and asphaltenes.8,9The asphaltenes are the most polar fraction and have the highest molecular weight,giving its dark color to the bitumen.The maltene fraction consists of polar aromatics,naphthene aromatics,and saturates.The ratio of the asphaltenes to the maltenes has a significant effect on the viscoelas-tic properties of bitumen and,consequently,on its performance as road paving binders.10Thus,road pave-ments may show different distresses depending on temperature s for example,rutting(or permanent de-formation at high temperatures)related to the viscosity of the bitumen matrix,and low-temperature cracking, as a result of brittle fracture of the glassy bitumen matrix.3,4,6,9The increasing traffic loading on road pavements has resulted in tightening of binder specifications in order to obtain a higher mechanical stability of asphalt roads. This has forced the use of natural or synthetic polymers to enhance the service properties of bitumen.11-13 Although,in many cases,polymer modification of bitu-men may result in a multiphase material with a clear tendency to phase separation,steric stabilization by copolymers,such as styrene-butadiene-styrene(SBS) block copolymers,has been proved very efficient to improve road performance.14This fact is related to the linear viscoelastic properties of SBS-modified bitumen. Thus,they are much more elastic than neat bitumen at high temperatures;on the contrary,in the low temperature region,the phase angle(relationship be-tween the viscous and elastic components)of modified binders decreases more slowly than the corresponding base bitumen as the temperature decreases.In sum-mary,SBS-modified bitumen shows less temperature susceptibility than neat bitumen.14,15The research of a binder with characteristics similar to those of a bitumen but with a greater easiness for its*Author to whom correspondence should be addressed.E-mail: martinez@uhu.es.(1)Vinogradov,G.V.;Isayev,A.I.;Zolotarev,V.;Verbskaya,E.A. Rheol.Acta1977,16,266-281.(2)Whiteoak, D.Shell Bitumen Handbook;Shell Bitumen UK, Riversdell Hause:Surrey,1990,14-16.(3)Adedeji,A.;Grunfelder,T.;Bates,F.S.;Macosko,C.W.;Stroup-Gardiner,M.;Newcomb,D.E.Polym.Eng.Sci.1996,36,1707-1723.(4)Lewandowski,L.H.Rubber Chem.Technol.1994,67,447-480.(5)Dongre´,R.;Youtcheff,J.;Anderson,D.A.Appl.Rheol.1996,6, 75-82.(6)Isacsson,U.;Lu,X.Mater.Struct.1995,28,139-159.(7)Lesueur,D.;Gerard,J.;Claudy,P.;Letoffe,J.J.Rheol.1996, 40,813-836.(8)Whiteoak, D.Shell Bitumen Handbook;Shell Bitumen UK, Riversdell Hause:Surrey,1990,88-91.(9)Ho,R.;Adedeji,A.;Giles,D.W.;Hajduk,D.A.;Macosko,C.W.; Bates,S.F.J.Polym.Sci.B:Polym.Phys.1997,35,2857-2877.(10)Ait-Kadi,A.;Brahimi,H.;Bousmina,M.Polym.Eng.Sci.1996, 36,1724-1733.(11)Collins,J.H.;Boulding,M.G.;Gelles,R.;Berker,A.Proc.Assoc. Asphalt Paving Technol.1991,60,43-79.(12)Kraus,G.Rubber Chem.Technol.1982,55,1389-1402.(13)King,G.N.;King H.W.;Harders,O.;Chaverot P.;Planche J. P.Proc.Assoc.Asphalt Paving Technol.1992,61,29-66.(14)Vonk,W.C.;van Gooswilligen,G.Shell Laboratorium:Am-sterdam,1991;Report8.18,1-14.(15)Lu,X.;Isacsson,U.JTEVA1997,25,383-390.131Energy&Fuels2000,14,131-13710.1021/ef990072f CCC:$19.00©2000American Chemical SocietyPublished on Web12/29/1999pigmentation has forced the oil industry to develop a new material.This binder should not be considered as a bitumen from the point of view of its chemical composition,although their physical characteristics have been considered as a goal and in several occasions improved.This new product called synthetic binder,or “clear binder”is basically a mixture of oil,resin,and polymer.Of course,the dark colored asphaltenes should be omitted in the formulation of a synthetic binder.Pigmentable synthetic binders are used for colored pavement applications,such as to alert the traffic to special situations,to improve the effect of illumination,etc.16The overall objective of this work was to formulate pigmentable synthetic binders with adequate mechan-ical properties.With this aim,this paper deals with the influences that mineral oil,resin,and SBS triblock copolymer concentrations exert on the linear viscoelastic properties of these materials in a wide range of tem-perature.Experimental SectionA nonmodified colophony resin (90%resinic acids)provided by Valcan S.A.(Spain),a process aromatic oil donated by Ertoil S.A.(Spain),and a styrene -butadi-ene -styrene triblock copolymer,Kraton D-1101CS,provided by Shell Chemical Company (U.K.)were used to formulate the synthetic binders.Some properties of these products are shown in Table 1.Melt model binders were prepared blending the three components in a low shear batch mixer at 150°C and a rotating speed of 60rpm.The compositions of the samples studied are shown in Table 2.Frequency sweeps,between 0.01and 100rad/s,in the linear viscoelasticity range were performed on a con-trolled-stress Haake RS100rheometer,using a profiled plate-and-plate geometry (20mm diameter and 1mm gap).Previously,stress sweep tests,at the frequency of 1Hz,were carried out on each sample to determinethe linear viscoelasticity region.Time sweep tests,at constant amplitude and frequency,were also carried out to confirm that no structural modifications occurred during the time required for each test.Measurements were done in a temperature range between 278and 323K.Dynamic mechanical analysis (DMA),in a tempera-ture range between 278and 350K,were performed on a controlled-stress Haake RS150rheometer,at a fre-quency of 0.1Hz,using the same plate-and-plate geometry and a heating rate of 1K/min.The morphologies of the binders were observed with a JEOL JSM-5410scanning electron microscope (20kV and 7500X),using samples coated with gold to avoid charging.The technical characterization of the samples was carried out according to the ASTM specifications.The results obtained are shown in Table 3.Results and DiscussionsLinear Viscoelastic Properties.Figure 1shows the frequency dependence of the storage and loss moduli for different synthetic binder samples (P5S,P7S,and P10S),having the same oil/polymer ratio,as a function of temperature.Three different regions may be observed in the dynamic mechanical spectrum of these systems,depending on SBS concentration and temperature.Thus,the transition to the glassy region is mainly observed at low temperatures,although an increase in SBS concentration shifts the characteristic frequency for the beginning of this region up to higher values.This region is characterized by an increase in the slope of the log -log plots of the linear viscoelasticity functions,storage,G ′,and loss,G ′′,moduli versus frequency and tends to disappear as temperature increases.A plateau region develops at a high SBS concentration,as tem-perature increases,showing values of G ′higher than G ′′.This region is characterized by a flattening of the slope of the storage modulus versus frequency.17On the contrary,a shoulder in G ′is found when the SBS concentration is not sufficiently high,being the values of G ′′higher than G ′.Finally,at high temperature (i.e.,323K),the beginning of the terminal or viscous region is clearly noticed in the low-frequency range,although the slope of the log -log plot of the storage modulus versus frequency is not proportional to 2.Figure 2shows the frequency dependence of the storage and loss moduli for synthetic binder samples having the same polymer concentration (i.e.,samples P740and P765),as a function of temperature.Once again,the previously mentioned regions of the dynamic mechanical spectrum clearly appear.As can be ob-served,a plateau region develops as temperature in-creases for the sample with the lowest resin concentra-tion (P740).On the contrary,the beginning of the transition region,at a given temperature,is displaced to lower frequencies as resin concentration increases.(16)Brule,B.;Le bourlot,F.;Potti,J.J .First Congress on Emulsion ;EDS:Paris,1993;4-11-193/01-05.Table 1.Properties of the Products Used in theFormulation of the Synthetic Binder Samples StudiedSBSstyrene content (%wt)31solution viscosity SMS2406(Pa ‚s) 4.0density ISO 2701(kg/m 3)940Colophony resinresinic acids content (%wt)90softennig point (Pa ‚s)(°C)84density (kg/m 3)1100Process oilviscosity at 25°C (Pa ‚s) 2.2viscosity at 50°C (Pa ‚s)73.4density (kg/m 3)at 25°C980Table positions of the Synthetic Binder SamplesStudiedP5SP6SP7SP8SP9S P10S P740P765oil (%wt)50.045.841.637.533.329.151.626.6resin (%wt)40.045.050.055.060.065.040.065.0SBS (%wt)10.09.18.37.5 6.65.88.38.3Table 3.Technological Characterization of the SyntheticBinder Samples StudiedP5SP6SP7S P8S P9S P10Spenetration (1/10mm)154163113874031softening point (°C)53.650.850.850.452.853.2Fraass breaking point (°C)-18.0-12.0-8.0-5.00.00.0PI 3.4 2.9 1.40.4-1.0-1.4132Energy &Fuels,Vol.14,No.1,2000Martı´nez-Boza et al.The evolution of the linear viscoelasticity functions with frequency,at 278K,for all the binders studied,is observed in Figure 3.At this temperature,all the samples exhibit an apparent transition region in the frequency range tested.The highest values of the storage and loss moduli correspond to samples with the largest resin content (see Table 2).For samples with the same resin concentration but different polymer content,i.e.,P10S and P765,the largest values of the viscoelastic moduli correspond to those samples with the highest polymer concentration.The behavior at 298K is quite different,as can be observed in Figure 4.Thus,in the low-frequency region,a shoulder in G ′appears,dampening the decrease of G ′with frequency in a magnitude that depends on polymer concentration.Consequently,although in the transition region the values of G ′always increase with resin concentration,in the above-mentioned region the maxi-mum values correspond to the sample with the highest polymer concentration,for samples having the same oil/polymer ratio,when a plateau region is clearly observed.Finally,at 323K,all the synthetic binder samples exhibit the beginning of the flow region,although in this case the values of the zero-shear-rate-limiting viscosity pass through a minimum at an intermediate polymer concentration,as has been confirmed by steady-state flow measurements.18The experimental values of the linear viscoelasticity functions may be empirically superposed using a shiftfactor,a T ,that follows an Arrhenius-like dependence on temperature:where E a is the activation energy and T o is the temper-ature of reference.Figure 5shows the resulting “master”curves for two samples with very different polymer concentrations,P5S and P10S.The temperature of reference is 298K.The different regions of the mechan-ical spectrum previously mentioned are apparent.Fur-thermore,the influence of polymer concentration is now clearly noticed.While the system with the lowest polymer concentration always shows higher values of the loss modulus and just a shoulder in G ′,the system having the largest content in polymer (P5S)shows a well-developed plateau region,with higher values of the storage modulus in a wide range of frequencies.Nevertheless,these synthetic binders are not ther-morheologically simple materials.Thus,the values of the shift factor obtained from dynamic linear viscoelas-ticity measurements cannot be used to superpose steady-state flow curves.18Moreover,the dynamic mechanical analysis tests carried out on the above-mentioned(17)Ferry,J.D .Viscoelastic Properties of Polymers ;John Wiley &Sons:New York,1980.(18)Martı´nez-Boza,F.J.Rheological characterisation of synthetic binders;Ph D.Thesis,University of Seville,1996.Figure 1.Frequency dependence of the storage and loss moduli for different synthetic binders (P5S,P7S,and P10S)and temperatures.a T )exp[E a R (1T -1T)](1)Linear Viscoelastic Properties of Synthetic Binders Energy &Fuels,Vol.14,No.1,2000133samples confirm that the time -temperature superposi-tion principle does not hold for these binders (Figure 6,parts a and b).This failure can be deduced from the comparison of the temperature dependence of the linear viscoelasticity functions obtained from frequency sweep tests (FS)and from temperature sweep tests (TS)carried out at a constant frequency.The values of the frequency sweep master curve have been converted using the Arrhenius-like relationship between the shift factor and temperature as follows:where E a is the activation energy obtained from fre-quency sweep tests,w exp is the reduced frequency calculated from the superposition of experimental fre-quency sweep curves at different temperatures,and w R is the frequency at which the temperature sweep tests are carried out.As may be seen,the differences between both types of curves are much more important as polymer concentration increases (sample P5S),a fact that corroborates significant microstructural changes in the binder depending on polymer concentration.Nev-ertheless,the previously mentioned regions of the mechanical spectrum are still observed,as well as a fully developed plateau region for the binder with the largest polymerconcentration.Figure 2.Frequency dependence of the storage and loss moduli for different synthetic binders (P740and P765)andtemperatures.Figure 3.Frequency dependence of the storage and lossmoduli for different synthetic binders at 278K.Figure 4.Frequency dependence of the storage and loss moduli for different synthetic binders at 298K.T )E a T oRT o ln(ωexp /ωR )+E a(2)134Energy &Fuels,Vol.14,No.1,2000Martı´nez-Boza et al.On the contrary,studies carried out on commercial synthetic binders containing a much lower polymer concentration (Figure 6c)demonstrate that the above-mentioned principle is held in a wide range of temper-atures,as other authors have previously stated for neat bitumen 5and polymer-modified bitumen.10As may be observed in the above-mentioned figure,no plateau region is shown,and just a slight decrease in the slope of the storage modulus is noticed,indicating much less important hydrodynamic interactions between the phases in the commercial synthetic binder.The evolution with temperature of the loss tangent,obtained from DMA tests,also confirms the significant influence of polymer concentration on the behavior of the binder in the low-temperature region.Thus,for binders having the same oil/polymer ratio,the maxi-mum in tan δ,which denotes the beginning of the transition to the glassy region,moves to lower temper-atures as polymer concentration increases,a fact that has been related to an improvement of its performance.On the contrary,for samples containing an identical polymer concentration,an increase in resin content shifts the beginning of the transition to the glassy region to higher temperatures.Relationship between Microstructure and Lin-ear Viscoelastic Properties.The experimental results obtained in this study may be satisfactorily explained taking into account the microstructure of these synthetic binders.As is well-known,SBS elastomers are es-sentially polybutadiene blocks tipped at all ends with polystyrene blocks.Polystyrene end-blocks separate into polystyrene domains,which cross-link the polybutadiene chains into a three-dimensional network.14If an SBS elastomer is added to a neat bitumen,it absorbs part of the maltene fraction with which the polymer is extended.Consequently,SBS-modified bitumen is a multiphase system formed by a polymer-rich phase and an asphaltene-rich phase.The SBS builds a three-dimensional network in the polymer-rich phase,which,depending on polymer concentration,may become the continuous one,forming a three-dimensional network throughout the whole bitumen.9In the case of synthetic binders,the polymer-rich phase would result from the absorption of some of the components of the oil fraction,with which the polymer would extend.The other phase would consist of the remaining oil fraction and the resin.At low SBS concentration,the polymer-rich phase is dispersed in the resin-rich phase matrix and its rheological response is similar to the one predicted by the emulsion model.Thus,the whole mixture would be a two-phase system for which the shoulder in G ′is due to the deformation-relaxation process of the dispersed phase.19,20If the SBS concentration is sufficiently high,the polymer-rich phase would be the continuous one.From a rheological point of view,the appearance of the plateau region in the dynamic mechanical spectrum of these binders,as polymer concentration or oil /polymer ratio increases,should indicate the development of the above-mentioned three-dimensional network.21,22This response is clearly seen in Figures 1and 2.Thus,an increase in polymer concentration (Figure 1),or a decrease in resin content at a constant polymer concen-tration yielding an increase in oil/polymer ratio (Figure 2),favors the development of a plateau region as the polymer-rich phase becomes more important.Both factors also seem to produce a decrease in the temper-ature at which the transition to the glassy region is noticed.In other words,an increase in polymer concen-tration (binders P5S,P7S,and P10S)or an increase in the oil/resin ratio at a constant polymer concentration (binders P740,P7S,and P765)decreases the elasticity of the binder in the low temperature region,a fact that could be related to a decrease in the glassy temperature of the resin.As can be seen,the temperature at which the maximum in the loss tangent appears is closely(19)Bousmina,M .Rheol.Acta 1999,38,73-83(20)Bousmina,M.;Bataille,P.;Sapieha,S.;Schreiber,H.P .J.Rheol .1995,39,499-516.(21)Bousmina,M.;Muller,R.Rheol.Acta 1996,35,369-381.(22)Bousmina,M.;Muller,R.J.Rheol.1993,37,663-679.Figure 5.Empirical master curves for samples P5S and P10S (temperature of reference:298K).Figure 6.Evolution of the linear viscoelasticity functions,obtained from DMA tests and frequency sweeps tests (using an empirical time -temperature superposition method),for a commercial synthetic binder and two synthetic binders (P5S and P10S)as a function of temperature.Linear Viscoelastic Properties of Synthetic Binders Energy &Fuels,Vol.14,No.1,2000135related to the oil/resin ratio (i.e.,1.2approximately forP5S and P740;0.4for P10S and P765).The morphology of the synthetic binders studied has been observed by SEM microscopy.Thus,the develop-ment of the above-mentioned three-dimensional net-work can be clearly seen in Figure 7,where SEM microphotographs of binders containing a constant oil/polymer ratio,at room temperature,are shown.TwoFigure 7.SEM micrographs for the synthetic binders studied.136Energy &Fuels,Vol.14,No.1,2000Martı´nez-Boza et al.different phases are noticed in sample P10S,a disperse phase,with a high density of gray,which corresponds to a polymer-rich phase,and a continuous phase,with a low density of gray,corresponding to a resin-rich phase.As may be observed,a higher polymer concentra-tion(P10S to P5S)increases the content in polymer-rich phase.At an intermediate polymer content(sample P8S),this phase seems to be the continuous one forming a three-dimensional network throughout the binder. This may explain some of the results previously re-ported.For example,thermo-rheological simplicity fails for binders with high polymer concentration(i.e.,P5S) in the temperature range studied(Figure6a),due to a dramatic change in the rheological properties of the binder at a temperature of about50°C;while the linear viscoelasticity functions of binder P10S obtained in a frequency sweep test are not significantly different from that obtained in a DMA test,after the application of an empirical time-temperature superposition method(Fig-ure6b).This change in microstructure may also explain the singular behavior of these binders in the flow region of the dynamic mechanical spectrum of binders having the same oil/polymer ratio.Thus,as was previously mentioned,the zero-shear-rate-limiting viscosity passes through a minimum at an intermediate polymer con-centration(sample P8S).A similar tendency is observed in the softening point values(see Table3).ConclusionsThe mechanical spectrum of the binders studied shows different regions:transition to glassy,plateau and beginning of the terminal region.The transition to the glassy region is mainly observed at low tempera-tures.An intermediate plateau region develops,as temperature increases,at high SBS concentration.The beginning of the terminal,or viscous region,is clearly noticed in the low-frequency range at high temperature. The experimental values of the linear viscoelasticity functions may be empirically superposed using a shift factor.Nevertheless,these synthetic binders are not thermorheologically simple materials.Thus,the values of the shift factor obtained from dynamic linear vis-coelastic measurements cannot be used to superpose steady-state flow curves.Furthermore,dynamic me-chanical analysis tests carried out confirm that the time-temperature superposition principle does not hold for these binders,above all for those containing a high polymer concentration.For binders having the same oil/polymer ratio,the beginning of the transition to the glassy region moves to lower temperatures as polymer concentration in-creases,a fact that has been related to an improvement of its performance.These results may be explained considering the development of a polymer-rich phase. If the SBS concentration is sufficiently high,this phase may become the continuous one.On the other hand,a continuous resin-rich phase may be observed at low polymer concentration,shifting the beginning of the transition to the glassy region to higher temperatures. EF990072FLinear Viscoelastic Properties of Synthetic Binders Energy&Fuels,Vol.14,No.1,2000137。