A Thermophysical Property Databank for Technically Important Gases and Liquids

A thermophysical property databank for technically important gases and liquids has been created. It provides users with data for nearly 30 substances: monatomic and diatomic gases, air, water and steam, carbon dioxide, ammonia, some hydrocarbons, and refrigerants. The coefficients of the equations of state and equations for calculating transport properties, the ideal-gas functions, the saturated vapor pressure, and the melting pressure are provided for each substance. The system of programs allows the calculation of the compressibility factor, density, enthalpy, entropy, isochoric and isobaric specific heats, speed of sound, Joule–Thomson coefficient, viscosity, and thermal conductivity and some other properties. These values can be determined in the single-phase and two-phase regions and on the phase-equilibrium lines at temperatures from the triple point up to 500 to 1500 K and at pressures up to 100 MPa (for monatomic and diatomic gases, up to 2500 to 3000 K and 300 MPa). Properties can be calculated for the following nine combinations of independent variables: T, ; T, p; T, s; T, x; p, ; p, h; p, s; p, x; and h, s. The software of the databank has a modular structure and permits an increase in the number of substances, properties, and independent variables.     

Development and Current Status of the Korea Thermophysical Properties Databank (KDB)

Physical property data, phase equilibrium data, and predictive models are essential parts of process design and operation. With the support of the Ministry of Commerce, Industry and Energy (MOCIE) of Korea, four universities collaborated to develop a thermophysical property databank and to obtain experimental data. In this paper topics related to the development and use of the thermophysical properties and phase equilibrium database are discussed. The databank contains about 4000 pure components and 5000 phase equilibrium data sets. Most of the data were collected along with the experimental uncertainties. Various estimation methods and thermodynamic models were included to calculate properties and phase equilibria. Data can be searched for with a stand-alone program or using an Internet web site. The current status and future prospects of the KDB (Korean Thermophysical Properties Databank) are discussed.     

Nondestructive Method for Determining the Thermophysical Properties and Temperature Transitions of Thermoplastics

A method is described making it possible to increase the efficiency and accuracy of determining thermophysical properties and temperature transitions of thermoplastic billets under production conditions without destroying them.__________Translated from Izmeritel’naya Tekhnika, No. 5, pp. 59–61, May, 2005.     

多元Al合金的热力学和热物理数据库的建立及凝固过程显微组织演变的模拟

介绍了相图热力学及热物理性能数据库的建立方法;综述了国内外学者构筑多元Al合金相图热力学和热物理性能数据库的研究工作。并介绍了使用相场方法,使用热力学和热物理性能数据库模拟多元Al合金凝固时显微组织演变的几个实例。最后展望了新一代热力学和热物理性能数据库建立及凝固过程显微组织演变定量模拟未来的可能发展方向。     

Overload effects on fatigue crack‐tip fields under plane stress conditions: surface and bulk analysis

The surface crack opening displacements are characterised by digital image correlation for a (thin) plane stress 316 stainless steel compact tension sample subjected to an overload event. This supports a traditional plasticity‐induced closure interpretation showing a knee in the closure response prior to overload, an absence of closure in the accelerated growth regime followed by accentuated closure in the retardation regime. By contrast, measurement of the mid‐thickness elastic strain field behind and ahead of the crack made by synchrotron X‐ray diffraction shows no evidence of significant crack face contact stresses behind the crack tip on approaching minimum loading. Rather the changes during loading and overloading can mostly be explained by a simple elastic plastic analysis using a value of the yield stress intermediate between the initial yield stress and the UTS. This shows very significant compressive reverse plastic strains ahead of the crack that start to form early during unloading. At the moment it is not clear whether this difference is because of the increasing stress intensity applied as the crack grows, or for some other reason, such as prevention of the crack faces closing mid‐thickness due to the reverse plastic zone.     

Automated System for Calculating Thermophysical Properties of Fluids and Thermal Processes of Cryogenic Plants

An automated system for calculating thermophysical properties of gases and liquids over a wide range of parameters has been developed. On the basis of values of the properties, the processes of isothermal compression, adiabatic throttling, polytropic expansion, heat exchange in two- and multi-stream heat exchangers, separation of vapor-liquid mixtures in the liquid vessel, and rectification in an air separation plant can be analyzed. For a specified structure scheme of a cryogenic plant, optimization of a corresponding thermodynamic cycle can be fulfilled.     

Specific Heat and Thermal Transport Measurements of Reactive Metallic Alloys by Noncontact Calorimetry in Reduced Gravity

Experimental concepts, application, and recent results of noncontact calorimetry inculding ac-specific heat and thermal transport property measurement of reactive metallic specimens are described. The method is based on induction heating in an electromagnetic levitation device. Experiments have been performed in reduced gravity onboard Spacelab. A heat flow model is discussed regarding conditions for precise specific heat determination from the temperature response to modulated heating power input as well as determination of thermal transport properties from the transient temperature response. Modulation techniques were developed for application in the metastable regime of the undercooled melt, where processing time is a critical issue. Results to be discussed include the total hemispherical emissivity of a bulk metallic glass-forming alloy revealing effects of surface segregation, thermal conductivity measurements, and application of ac calorimetry in the two-phase region.     

Thermophysical Properties and Normal Spectral Emittance of Iridium up to 3500 K

An ohmic pulse-heating experiment together with radiometry and μs-photopolarimetry is deployed at the Institute of Experimental Physics, Graz University of Technology, to obtain temperature-dependent thermophysical properties of conducting samples in the solid and molten states. This experimental setup has been used within the present work to gather data for solid and liquid iridium. Results for both thermophysical properties, as well as the normal spectral emittance obtained at a wavelength of 684.5 nm up to 3500 K are reported. The newly obtained values for iridium are presented in graphical and tabular form and compared to available literature data. The uncertainties for all reported properties are stated and it follows that, considering these expanded uncertainties, the recent data are in very good agreement with literature sources. Mutually motivated by these good results and by the scarce (if any) data available for the liquid state, the thermal conductivity and thermal diffusivity of liquid iridium are estimated by means of the Wiedemann–Franz law.     

Absolute Measurement of Thermophysical and Optical Thin-Film Properties by Photothermal Methods for the Investigation of Laser Damage

Perspectives and limits of the application of the photothermal technique are given for the measurement of absorption, thermal, and thermoelastic properties in thin films. The peculiarities of this technique in the frequency and time domains are discussed in some detail, and selected important results with respect to laser damage studies in optical coatings are pointed out. Emphasis is placed on the absolute measurement of both optical and thermophysical properties in dielectric materials in thin-film form and, also, on the influence of both absorption and changed thermal properties in thin films on their thermally induced laser damage resistance.     

金属箔饰面家具表面理化性能检测及标准化研究

本文提出了金属箔饰面家具的表面理化性能研究的必要性,并从表面胶合强度、表面漆膜理化性能(耐液性、耐湿热、耐干热、附着力、耐冷热温差、耐磨性、抗冲击)等多个方面提出了检测要求和试验方法,通过验证试验证明了良好的测试效果,并在最后展望了应用前景。     

Structure and Thermophysical Properties of Fullerene C60 Aqueous Solutions

The structure and thermophysical properties of fullerene C₆₀aqueous solutions were investigated both experimentally and theoretically. The aggregation kinetics results indicated that the structure of fullerene C₆₀aggregates in water could be described as a fractal system. The IR and electronic absorption spectra obtained confirm the presence of the crystalline phase in aqueous solution. The numerical values of thermodynamic coefficients _P, _T, _S,c _P, andc _V, and sound velocity were determined from the measured (P–V–T) data. The vibrational spectrum of the crystalline structure (T_hsymmetry group) formed from the hydrated single fullerene C₆₀molecules in aqueous solutions was calculated using the molecular dynamics approach.     

Setting Up a Databank on the Properties of Substances and Materials: A Task Undertaken by the State Reference Data Service

Research results are reported for a databank on the thermophysical properties of substances and materials, which covers researches in the Soviet Union and Russia between 1950 and 2000. An archive of 3475 documents has been set up, which provides bibliographic information on the publications containing the original experimental data and which has been implemented in the Lotus Notes environment. The database organization and retrieval in it are considered.     

Thermophysical Properties of Solid and Liquid Ti-6Al-4V (TA6V) Alloy

Ti-6Al-4V (TA6V) titanium alloy is widely used in industrial applications such as aeronautic and aerospace due to its good mechanical properties at high temperatures. Experiments on two different resistive pulse heating devices (CEA Valduc and TU-Graz) have been carried out in order to study thermophysical properties (such as electrical resistivity, volume expansion, heat of fusion, heat capacity, normal spectral emissivity, thermal diffusivity, and thermal conductivity) of both solid and liquid Ti-6Al-4V. Fast time-resolved measurements of current, voltage, and surface radiation and shadowgraphs of the volume have been undertaken. At TU-Graz, a fast laser polarimeter has been used for determining the emissivity of liquid Ti-6Al-4V at 684.5 nm and a differential scanning calorimeter (DSC) for measuring the heat capacity of solid Ti-6Al-4V. This study deals with the specific behavior of the different solid phase transitions (effect of heating rate) and the melting region, and emphasizes the liquid state (T > 2000 K).     

Structural Stability and Half Metallic Features of Zn0.5Cr0.5S under Pressure

Spin-polarized first-principle was performed to study the structural stability and the electronic states of Cr doped ZnS with the Cr component of 50% in zincblende （ZB）, wurtzite （W） and rocksalt （RS） structures under pressure. The results show that the zincblende and wurtzite structures become unstable under low pressures of about 4.68 and 9.61 GPa, respectively, but the rocksalt structure can be maintained up to an extremely high pressure of about 32.92 GPa. Both zincblende and wurtzite Zno.sCro.5S display half metallic features under pressure, while rocksalt Zno.sCro.sS exhibits metallic feature. The half metallic features can be ascribed to the stronger interactions between S-3p and Cr-3d states and the metallic feature is due to the higher crystal symmetry of rocksalt Zn0.5Cr0.5S. These results can provide helpful guidance for Cr doped ZnS to be used in spintronic devices.     

Normal Spectral Emissivity at a Wavelength of 684.5 nm and Thermophysical Properties of Solid and Liquid Molybdenum

Polarimetric emissivity measurements adapted for a rapid pulse heating setup and recent results of normal spectral emissivity at 684.5 nm for molybdenum at melting and in the liquid phase are presented. Also reported is a complete set of thermophysical data (specific enthalpy, isobaric heat capacity, electrical resistivity, thermal conductivity, and thermal diffusivity) for molybdenum for both solid and liquid states. The results for all mentioned thermophysical properties are discussed and furthermore compared to literature values. The normal spectral emissivity and the electrical resistivity of molybdenum show opposite trends in the liquid phase, leading to the conclusion that a prediction of normal spectral emissivity at the given wavelength of 684.5 nm based on the Hagen–Rubens-relation and electrical resistivity measurements is not applicable.     

热物理性质测试技术研究现状和发展趋势

本文在对热物理性质研究在热能工程、材料科学、信息科学、航天工程、环境工程、生物科学、微电子技术和计量学等众多科技领域中的重要性进行探讨的基础上,评述了热物理性质测试技术的研究现状和发展趋势。鉴于薄膜材料在微电子器件、集成电路和微电子机械系统等领域中日益广泛的应用,本文还综述了亚微米－纳米尺度薄膜材料热导率和热扩散率的测试新技术。     

泡沫金属——高分子聚合物的复合体机械阻尼性能研究

本文研究了泡沫金属和同分子聚合物形成的复合体机械阻尼性能，结果表明它是一种内耗值Ｑ＾－１极高的阻尼材料，其阻尼特征表现为与应变振幅密切相关而与频率无显著关系的非线性内耗。同时研究了泡沫金属孔隙结构对复合体内耗值的影响关系，并对实验结果进行了讨论。     

Graphite Melting and Properties of Liquid Carbon

The results of fast heating (by electrical pulse current) of highly oriented pyrolytic graphite specimens are presented. Experimental data are obtained for graphite melting: the enthalpy of solid and liquid phases under melting, the heat of melting, and the heat capacity of solid and liquid phases near melting. Liquid carbon resistivity is measured under fast heating of cylindrical graphite specimens in thick-walled sapphire capillary tubes. Preliminary data for the isobaric heat capacity C_p for liquid carbon up to 10,000 K and for the isochoric heat capacity C_v up to 8000 K are presented.     

Structure and Mechanical Properties of AFS Sandwiches Studied by in‐situ Compression Tests in X‐ray Microtomography

Al foam core / Al alloy skins sandwiches have potential for application in light weight structures. Recently, the foaming processes have improved and large, thick and 3D‐shape panels can be produced using the precursor technology. The microstructure of an AFS sandwich is analysed in this paper at a microscale and a mesoscale using X‐ray tomography and conventional SEM analysis. The main deformation mechanism of the core under compression is also studied thanks to in situ test. It is shown that the foam first present plastic buckling and then walls rupture. This is well correlated to the microstructure of the constitutive material of the core.