From Wikipedia, the free encyclopedia
This article needs additional citations for . Please help
by . Unsourced material may be challenged and removed. (February 2015)
A rheometer is a laboratory device used to measure the way in which a liquid, suspension or slurry flows in response to applied forces. It is used for those fluids which cannot be defined by a single value of
and therefore require more parameters to be set and measured than is the case for a . It measures the
of the fluid.
There are two distinctively different types of rheometers. Rheometers that control the applied
or shear strain are called rotational or , whereas rheometers that apply
or extensional strain are . Rotational or shear type rheometers are usually designed as either a native strain-controlled instrument (control and apply a user-defined shear strain which can then measure the resulting shear stress) or a native stress-controlled instrument (control and apply a user-defined shear
and measure the resulting shear strain).
The word rheometer comes from the Greek, and means a device for measuring flow. In the 19th century it was commonly used for devices to measure electric current, until the word was supplanted by
and . It was also used for the measurement of flow of liquids, in medical practice (flow of blood) and in civil engineering (flow of water). This latter use persisted to the second half of the 20th century in some areas. Following the coining of the term
the word came to be applied to instruments for measuring the character rather than quantity of flow, and the other meanings are obsolete. (Principal Source: ) The principle and working of rheometers is described in several texts.
A , commonly known as DSR is used for research and development as well as for quality control in the manufacture of a wide range of materials. Dynamic shear rheometers have been used since 1993 when Superpave was used for characterising and understanding high temperature rheological properties of asphalt binders in both the molten and solid state and is fundamental in order to formulate the chemistry and predict the end-use performance of these materials.
Photo of Dynamic Shear Rheometer sold by Cooper Research Technology Ltd.
Commercial Capillary Viscometer
Liquid is forced through a tube of constant cross-section and precisely known dimensions under conditions of . Either the flow-rate or the pressure drop are fixed and the other measured. Knowing the dimensions, the flow-rate can be converted into a value for the
and the pressure drop into a value for the . Varying the pressure or flow allows a flow curve to be determined. When a relatively small amount of fluid is available for rheometric characterization, a microfluidic rheometer with embedded pressure sensors can be used to measure pressure drop for a controlled flow rate.
modular Rotational Rheometer with cylinder and cone/plate and plate/plate measuring systems
The liquid is placed within the
of one cylinder inside another. One of the cylinders is rotated at a set speed. This determines the
inside the annulus. The liquid tends to drag the other cylinder round, and the force it exerts on that cylinder () is measured, which can be converted to a . One version of this is the Fann V-G Viscometer, which runs at two speeds, (300 and 600 rpm) and therefore only gives two points on the flow curve. This is sufficient to define a
model which used to be widely used in the
for determining the flow character of . In recent years rheometers that spin at 600, 300, 200, 100, 6 & 3 RPM have been used. This allows for more complex fluids models such as
to be used. Some models allow the speed to be continuously increased and decreased in a programmed fashion, which allows the measurement of time-dependent properties.
The liquid is placed on horizontal plate and a shallow cone placed into it. The angle between the surface of the cone and the plate is of the order of 1 degree—i.e. it is a very shallow cone. Typically the plate is rotated and the force on the cone measured. A well-known version of this instrument is the Weissenberg Rheogoniometer, in which the movement of the cone is resisted by a thin piece of metal which twists—known as a . The known response of the
and the degree of twist give the , while the rotational speed and cone dimensions give the . In principle the Weissenberg Rheogoniometer is an absolute method of measurement providing it is accurately set up. Other instruments operating on this principle may be easier to use but require calibration with a known fluid. Cone and plate rheometers can also be operated in an oscillating mode to measure elastic properties, or in combined rotational and oscillating modes.
One example of a linear shear rheometer is the Goodyer Linear Skin Rheometer, which is used to test cosmetic cream formulations, and for medical research purposes to quantify the elastic properties of tissue. The device works by attaching a linear probe to the surface of the tissue under test, a controlled cyclical force is applied, and the resultant shear force measured using a load cell. Displacement is measured using an LVDT. Thus the basic stress/strain parameters are captured and analysed to derive the Dynamic Spring Rate of the tissue under test.
The development of extensional rheometers has proceeded more slowly than shear rheometers, due to the challenges associated with generating a homogeneous extensional flow. Firstly, interactions of the test fluid or melt with solid interfaces will result in a component of shear flow, which will compromise the results. Secondly, the strain history of all the material elements must be controlled and known. Thirdly, the strain rates and strain levels must be high enough to stretch the polymeric chains beyond their normal radius of gyration, requiring instrumentation with a large range of deformation rates and a large travel distance.
Commercially available extensional rheometers have been segregated according to their applicability to viscosity ranges. Materials with a viscosity range from approximately 0.01 to 1 Pa.s. (most polymer solutions)are best characterized with capillary breakup rheometers, opposed jet devices, or contraction flow systems. Materials with a viscosity range from approximately 1 to 1000 Pa.s. are used in filament stretching rheometers. Materials with a high viscosity &1000 Pa.s., such as polymer melts, are best characterized by constant-length devices.
Extensional rheometry is commonly performed on materials that are subjected to a tensile deformation. This type of deformation can occur during processing, such as injection molding, fiber spinning, extrusion, blow-molding, and coating flows. It can also occur during use, such as decohesion of adhesives, pumping of hand soaps, and handling of liquid food products.
A list of currently and previously marketed commercially available extensional rheometers is shown in the table below.
Instrument Name
Viscosity Range [Pa.s]
Manufacturer
Currently Marketed
Fiber spinning
Capillary breakup
ThermoFisher
Sentmanat extensional rheometer
Constant length
Xpansion Instruments
Filament stretching
Cambridge Polymer Group
Previously Marketed
Opposed Jet
Rheometric Scientific
Constant length
Rheometric Scientific
Constant length
Magna Projects
The Rheotens is a fiber spinning rheometer, suitable for polymeric melts. The material is pumped from an upstream tube, and a set of wheels elongates the strand. A force transducer mounted on one of the wheels measures the resultant extensional force. Because of the pre-shear induced as the fluid is transported through the upstream tube, a true extensional viscosity is difficult to obtain. However, the Rheotens is useful to compare the extensional flow properties of a homologous set of materials.
The CaBER is a capillary breakup rheometer. A small quantity of material is placed between plates, which are rapidly stretched to a fixed level of strain. The midpoint diameter is monitored as a function of time as the fluid filament necks and breaks up under the combined forces of surface tension, gravity, and viscoelasticity. The extensional viscosity can be extracted from the data as a function of strain and strain rate. This system is useful for low viscosity fluids, inks, paints, adhesives, and biological fluids.
The FiSER is based on the works by Sridhar et al. and Anna et al. In this instrument, a set of linear motors drive a fluid filament apart at an exponentially increasing velocity while measuring force and diameter as a function of time and position. By deforming at an exponentially increasing rate, a constant strain rate can be achieved in the samples (barring endplate flow limitations). This system can monitor the strain-dependent extensional viscosity, as well as stress decay following flow cessation. A detailed presentation on the various uses of filament stretching rheometry can be found on the MIT web site.
The Sentmanat extensional rheometer (SER) is actually a fixture that can be field installed on shear rheometers. A film of polymer is wound on two rotating drums, which apply constant or variable strain rate extensional deformation on the polymer film. The stress is determined from the torque exerted by the drums.
employ a piezo-electric crystal that can easily launch a successive wave of extensions and contractions into the fluid. This non-contact method applies an oscillating extensional stress. Acoustic rheometers measure the sound speed and attenuation of ultrasound for a set of frequencies in the megahertz range. Sound speed is a measure of system elasticity. It can be converted into fluid compressibility. Attenuation is a measure of viscous properties. It can be converted into viscous longitudinal modulus. In the case of a Newtonian liquid, attenuation yields information on the volume viscosity. This type of rheometer works at much higher frequencies than others. It is suitable for studying effects with much shorter
than any other rheometer.
A simpler version of the filament stretching rheometer, the falling plate rheometer sandwiches liquid between two solid surfaces. The top plate is fixed, and bottom plate falls under the influence of gravity, drawing out a string of the liquid.
Other systems involve liquid going through an orifice, expanding from a capillary, or sucked up from a surface into column by a vacuum.
Macosko, Christopher W. (1994). Rheology: Principles, Measurements, and Applications. Wiley-VCH.  .
Ferry, JD (1980). Viscoelastic Properties of Polymers. Wiley.  .
Pipe, CJ; Majmudar, TS; McKinley, GH (2008). "High Shear-Rate Viscometry". Rheologica Acta 47 (5-6): 621–642. :.
Chevalier, J; Ayela, F. (2008). "Microfluidic on chip viscometers". Rev. Sci. Instrum. 79: 076102. :. :.
Springer Handbook of Experimental Fluid Mechanics, Tropea, Foss, Yarin (eds), Chapter 9.1(2007)
Sridhar, J. Non-Newtonian Fluid Mech., vol 40, 271-280 (1991); Anna, J. Non-Newtonian Fluid Mech., vol 87, 307-335 (1999)
McKinley, G. . web.mit.edu.
K. Walters (1975) Rheometry (Chapman & Hall)
A.S.Dukhin and P.J.Goetz "Ultrasound for characterizing colloids", Elsevier, (2002)
: Hidden categories:rotational rheometer的用法和样例：
Viscosity, dynamic properties and interfacial morphology of the composite were investigated by ARES rotational rheometer and scanning electron microscopy (SEM).
采用ARES型旋转式流变仪和扫描电镜(SEM)对材料的熔体粘度、动态特性以及界面形态作了研究。
high pressure rotational rheometer
加压旋转流变仪
high- pressure intelligent rotational rheometer
高压智能旋转流变仪
DESIGN AND CALIBRATION FOR HIGH-PRESSURE ROTATIONAL RHEOMETER OF HIGH VISCOUS AND DENSE MATERIAL
高浓度粘稠物料加压旋转流变仪的研制与标定
Keywords high-pressure intelligent rotational rheometer;
高压智能旋转流变仪;机械结构;设计方案;
rotational rheometer的海词问答与网友补充：
rotational rheometer的相关资料：
相关词典网站：的翻译结果:
查询用时：0.371秒
&在分类学科中查询
From the Idea of Lifelong Sports Study the Reform and Development of the School PE in Our Country
从终身体育思想审视我国学校体育的改革与发展
A Study of Applying ISO9000 to the Higher PE Academy Education Management
ISO9000在高等体育院校教育管理中的应用研究
PE Course Resources System Theory and Its Application in College PE Courses: An Empirical Study
体育课程资源系统理论及其在高校体育课程中运用的实证研究
A FUZZY METHOD FOR COMPREHENSIVELY ASSESSING PE—TECHERS WORK
综合评价体育教师工作成绩的模糊数学方法
Forecast Studies of the Demand for PE Teachers by Middle Schools in Shanghai from 1986 to 2000
上海市普通中学年体育师资需求的预测研究
Study on the Synthesis of PE In-situ Alloys by Gas-phase and the Relationship between Its Properties and Structure
气相法聚乙烯原位合金的合成及其结构—性能关系的研究
Studies of PP/PE Blending (1),(2)
聚丙烯聚乙烯共混研究(1)(2)
The Reactions and Properties for Peroxide-crossl inked Polyethylene (PE)
过氧化物交联聚乙烯的反应与性能
EFFECTS OF SPACE CHARGE AND FRICTIONAL ELECTRIFICATION OF MIXTURE OF PE WITH EVA
聚乙烯与 EVA 共混物的空间电荷和摩擦带电效应
Measurement of “Mirror Effect” of PE Melt by Rotational Rheometer
旋转流变仪测定聚乙烯熔体的“镜面效应”
(3)The result of comprehensive appraisal towards the students who major in PE of Liaoning normal university shows that very capable is 21%, stronger is 24%, generally is 25%, weaker is 15%, very weak is 15%.
(3)对辽宁师范大学体育教育专业应届生能力综合评判结果,能力很强21%,较强24%,一般25%,较弱15 %,很弱15%。
Study on the New Aim System of PE in College
关于建立健全新高校体育教育目标体系研究
On quality education for PE in the new period
试析新时期体育教育中的素质教育因素
The historical background of the modern view of health and the thought'Health First',its connotation and denotation and its relationship with 'PE'were develolped.
对现代健康观 ,“健康第一”思想产生的历史背景 ,“健康第一”思想的内涵与外延以及它与体育教育的关系进行了剖解和探讨 .
Study on Development and Reform of PE Teacher Education Curriculum Toward 21～(st) Century in
面向21世纪我国体育教师教育课程改革研究——体育教育专业本科课程发展的历史回顾、展望及改革对策
Study on the Evaluation of
Teaching Quality in PE Lessons
体育课教学质量评估研究
to form multi-evaluation contents and approaches of PE
建立评价内容多元、评价方法多样的体育课成绩评价体系;
It is a comparison and study of traditional and reform modes of PE instruction.
通过对高校传统体育课教学模式与改革后的体育课教学模式进行比较分析。
The Practice and Summary of the Reformation
of College Girl Studens' PE
大学女学生体育课改革的实践与总结
Optimizing Teaching Environment For a High-quality Teaching of PE
优化教学环境
提高体育课教学质量
查询“pe”译词为用户自定义的双语例句&&&&我想查看译文中含有：的双语例句
为了更好的帮助您理解掌握查询词或其译词在地道英语中的实际用法，我们为您准备了出自英文原文的大量英语例句，供您参考。&&&&&&&&&&&&&&&&&&&& Controlled crosses made between apple×pemunis,P.serotina,P. Bretchneideri,P.ussuriensis),apple×plum,apple×cherry,apple×peach(P.pe- rsica,p.Davidii),apple×apricot,and apple×strawberry from 1953 to 1955 have proved that hybrid seeds can be obtained even between sub-families,except the strawberry.The percentage of fruit setting varied with the remoteness of the phylogenetical relation befween female and male parents,ie.apple×pear higher than apple×stone fruits.For differen... &&&&&&&&&&&&一、用一般的套袋授粉法进行苹果和梨、和核果类桃、李、樱桃、山杏、山毛桃等组合的有性杂交可以获得杂交果实和种子。二、杂交的结实率因父本的种类而不同,苹果和梨(仁果类)杂交结实率、结种子率一般较苹果和桃、李、樱桃等核果类为大。三、母本苹果不同品种不同的自然及栽培条件下成功的可能性不同。因此在进行远缘杂交时应同时选几个品种作为母本,在不同年份连续进行较易获得成功。四、先授以远缘花粉隔四小时后再授以限量近缘花粉的混合授粉法所得结果不可靠。是否用延长间隔时间或采用丧失发芽力的近缘花粉的混合授粉法以促进杂交结实而不致引起差误有待于进一步研究。五、用去雄后6天进行授粉的衰老柱头授粉法,似不宜用于一般杂交结实尚不很困难的苹果和梨之间的杂交,但用于苹果和某些核果类果树之间的杂交似有促进作用。六、以父本种类作砧木对母本进行教养影响的无性渐近杂交法显著地提高了苹果和梨远缘杂交的结实率。七、远缘杂种生活力弱,幼苗甚易夭折,一般从茎的基部或地下部分开始变褐,渐渐全株枯死。杂种部分植株表现父本梨或全新性状,表现这些性状的植株生活力尤为衰弱。如何克服杂种幼苗的夭折尚待继续研究。&&&&&&&& Л　epeaToHoe oTHoeHe peykTopa Mey ekTpoBaTee paoMMexaHMoM MeeT pMoe BHe Ha TexHecko-koHoMecke okaaTeekTpopBoa. paBbHbI BbIop epeaToHoo oTHoeH HoMHab-Ho ckopocT ekTpoBaTe BeTc oHM 3 BaHx BopocoB B po-ekTpoBaH ekTpopBooB. B HacToe cTaTbe oeHbI cyecTByoe MeToLI BbIopa oTMa-bHoo epeaToHoo ca HekoTopbIx ocHoBHbIx cyaeB。ABTopoM pe-aaTc ooHTebHbIe cyeH k HekoTopbIM paccMoTpeHHbIM cyaM. 40 eT ToMy Haa, HayHbIe cceoBaTe Haa yaTb paccMoTpeH-HbI B aHHo cTaTbe Bopoc。 cxo ycoB paroHa poBocTBeHHoro MexaHMa o a... &&&&&&&&&&&&电动机和生产机械间的变速装置的传速比,直接影响到电力拖动装置的技术经济指标。正确地选择传速比及相应的电动机额定转速,是设计电力拖动装置的一个重要问题。 在本文中阐述了在几种主要情况下现有的选择最佳传速比的方法。作者对於某些情况提出了一些补充意见。 在四十多年以前就有一些学者开始研究本文中所讨论的问题。L.A.尤曼斯基根据生产机械起动到给定的速度,能保证起动时间最短的条件出发,导出了计算传速比的公式。А.И.采利柯夫也导出了同样的公式,但是他是根据在给定的时间内,使生产机械的工作轴能转过最多转数的条件出发。 H.A.齐申科对于生产机械以一定的速度旋转,忽略负载转矩,保证起动制动时间最短的情况,导出了计算公式。而Р.Л.阿朗诺夫的公式则是考虑负载转矩的影响,而假定起动转矩同制动转矩相等。 本文作者在同样的条件下,既考虑负载转矩,又考虑起动转矩与制动转矩的不等,得出如下的方程式: GD_δ~2MтMпK~4+2GD_δ~2Mм(Mп-Mт)K~3-(GDм~2MтMп+3GD_δ~2Mм~2)K~2- -GDм~2Mм~2=0。上述的公式都可以看成是这个普遍方程式的特例。 这个方程式与А.И.采利柯夫和Н.П.库尼...&&&&&&&& (Consisting of two articles, the first one was published in 1938 in the Singchow Semi-monthly Singapore, the second is a much more detailed one written in 1957. Followingis a general sketch of both the two articles.) Ⅰ. What is the Malayan Stock? In common sense, Malayan stock means the Malayan race or Brown race, which isone of the five human races of the world. The classic method of the classification ofhuman races according to their skin colour gave the Malayans the pseudo-scientific name"Brown race" whi... &&&&&&&&&&&&林惠祥同志三十多年来除了对人类学(包括古学、民族学)进行系统的研究,并获得很大的成就和贡献外,他一生对南洋问题的研究,也曾下过工夫,做过不少工作和贡献。“南洋马来族与华南古民族的关系”这篇论文是林惠祥同志关于南洲问题最后的遗著。前篇于一九三八年以“马来人与中国东南方人同源说”为题曾在南洋发表过,后篇是他二十年后对这问题进一步深入研究的成果,提出更丰富、更可靠的有关人类学(包括考古学、民族学)的材料和证据,把我国和南洋民族的历史关系以及将东南亚这一大片地方过去被遗忘的历史补充起来,这是他三十年多年来对南洋研究的重要贡献,也是他一生对南洋问题研究总结的一部份。&nbsp&&&&&&&&相关查询:
在Springer中查有关
在知识搜索中查有关的内容
在数字搜索中查有关的内容
在概念知识元中查有关的内容
在学术趋势中查有关的内容
2008 CNKI－中国知网
北京市公安局海淀分局 备案号：110 1081725
&2008中国知网(cnki) 中国学术期刊(光盘版)电子杂志社}