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Sample records for thermal properties laboratory

  1. Laboratory measurements of rock thermal properties

    DEFF Research Database (Denmark)

    Bording, Thue Sylvester; Balling, N.; Nielsen, S.B.

    The thermal properties of rocks are key elements in understanding and modelling the temperature field of the subsurface. Thermal conductivity and thermal diffusivity can be measured in the laboratory if rock samples can be provided. We have introduced improvements to the divided bar and needle...... probe methods to be able to measure both thermal conductivity and thermal diffusivity. The improvements we implement include, for both methods, a combination of fast numerical finite element forward modelling and a Markov Chain Monte Carlo inversion scheme for estimating rock thermal parameters...

  2. Rapid laboratory investigation of the thermal properties of planetary analogues by using the EXTASE thermal probe.

    Science.gov (United States)

    Nadalini, R.; Extase Team

    The thermal properties of the constituent materials of the upper meters of planets and planetary bodies are of extreme interest. During the design and the verification of various planetary missions, the need to model and test appropriate simulants in laboratory is often raised. To verify the thermal properties of deployed laboratory simulants, the EXTASE thermal probe is a fast, precise, and easy-to-use tool. EXTASE is a thermal profile probe, able to measure the temperature and inject heat into the selected material at 16 different locations along its 45cm long slender cylindrical body. It has been developed following the experience of MUPUS, with the purpose of observing such properties on Earth, in situ and in a short time. We have used EXTASE, under laboratory cold and standard conditions, on several sand mixtures, soils, granular and compact ices, under vacuum and at normal pressure levels, to collect a great number of time- and depth-dependent temperature curves that represent the thermal dynamical response of the material. At the same time, two independent models have been developed to verify the experimental results by reaching the same results with a simulation of the same process. The models, analytical and numerical, which account for all material parameters (conductivity, density, capacity), have been developed and fine tuned until their results are superposed to the experimental curves, thus allowing the determination of the distinct thermal properties. In addition, a test campaign is under planning to use EXTASE to determine, rapidly and efficiently, the thermal properties of various regolith simulants to be used in the simulation of planetary subsurface processes.

  3. Thermal Property Engineering: Exploiting the Properties of Ceramic Nanocomposites

    Science.gov (United States)

    2018-03-01

    ARL-TR-8308 ● MAR 2018 US Army Research Laboratory Thermal Property Engineering : Exploiting the Properties of Ceramic...return it to the originator. ARL-TR-8308 ● MAR 2018 US Army Research Laboratory Thermal Property Engineering : Exploiting the...2015 – Dec 31 2017 4. TITLE AND SUBTITLE Thermal Property Engineering : Exploiting the Properties of Ceramic Nanocomposites 5a. CONTRACT NUMBER 5b

  4. Thermal Properties Measurement Report

    Energy Technology Data Exchange (ETDEWEB)

    Carmack, Jon [Idaho National Lab. (INL), Idaho Falls, ID (United States); Braase, Lori [Idaho National Lab. (INL), Idaho Falls, ID (United States); Papesch, Cynthia [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hurley, David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Tonks, Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhang, Yongfeng [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gofryk, Krzysztof [Idaho National Lab. (INL), Idaho Falls, ID (United States); Harp, Jason [Idaho National Lab. (INL), Idaho Falls, ID (United States); Fielding, Randy [Idaho National Lab. (INL), Idaho Falls, ID (United States); Knight, Collin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Meyer, Mitch [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-08-01

    The Thermal Properties Measurement Report summarizes the research, development, installation, and initial use of significant experimental thermal property characterization capabilities at the INL in FY 2015. These new capabilities were used to characterize a U3Si2 (candidate Accident Tolerant) fuel sample fabricated at the INL. The ability to perform measurements at various length scales is important and provides additional data that is not currently in the literature. However, the real value of the data will be in accomplishing a phenomenological understanding of the thermal conductivity in fuels and the ties to predictive modeling. Thus, the MARMOT advanced modeling and simulation capability was utilized to illustrate how the microstructural data can be modeled and compared with bulk characterization data. A scientific method was established for thermal property measurement capability on irradiated nuclear fuel samples, which will be installed in the Irradiated Material Characterization Laboratory (IMCL).

  5. Thermal insulation properties of walls

    Directory of Open Access Journals (Sweden)

    Zhukov Aleksey Dmitrievich

    2014-05-01

    Full Text Available Heat-protective qualities of building structures are determined by the qualities of the used materials, adequate design solutions and construction and installation work of high quality. This rule refers both to the structures made of materials similar in their structure and nature and mixed, combined by a construction system. The necessity to ecaluate thermal conductivity is important for a product and for a construction. Methods for evaluating the thermal protection of walls are based on the methods of calculation, on full-scale tests in a laboratory or on objects. At the same time there is a reason to believe that even deep and detailed calculation may cause deviation of the values from real data. Using finite difference method can improve accuracy of the results, but it doesn’t solve all problems. The article discusses new approaches to evaluating thermal insulation properties of walls. The authors propose technique of accurate measurement of thermal insulation properties in single blocks and fragments of walls and structures.

  6. Comparison of Thermal Properties Measured by Different Methods

    International Nuclear Information System (INIS)

    Sundberg, Jan; Kukkonen, Ilmo; Haelldahl, Lars

    2003-04-01

    A strategy for a thermal site descriptive model of bedrock is under development at SKB. In the model different kinds of uncertainties exist. Some of these uncertainties are related to the potential errors in the methods used for determining thermal properties of rock. In two earlier investigations thermal properties of rock samples were analysed according to the TPS method (transient plane source). Thermal conductivity and thermal diffusivity were determined using the TPS method. For a comparison, the same samples have been measured at the Geological Survey of Finland (GSF), using different laboratory methods. In this later investigation, the thermal conductivity was determined using the divided-bar method and the specific heat capacity using a calorimetric method. The mean differences between the results of different methods are relatively low but the results of individual samples show large variations. The thermal conductivity measured by the divided bar method gives for most samples slightly higher values, in average about 3%, than the TPS method. The specific heat capacity measured by the calorimetric method gives lower values, in average about 2%, than the TPS method. Consequently, the thermal diffusivity calculated from thermal conductivity and specific heat capacity gives higher values, in average about 6%, than the TPS method. Reasons for the differences are estimated mainly to be dependent on differences between the samples, errors in the temperature dependence of specific heat and in the transformation from volumetric to specific heat. The TPS measurements are performed using two pieces (sub-samples) of rock. Only one of these two sub-samples was measured using the divided bar method and the calorimetric method. Further, sample preparation involved changes in the size of some of the samples. The mean differences between the results of different methods are within the margins of error reported by the measuring laboratories. However, systematic errors in

  7. Comparison of Thermal Properties Measured by Different Methods

    Energy Technology Data Exchange (ETDEWEB)

    Sundberg, Jan [Geo Innova AB, Linkoeping (Sweden); Kukkonen, Ilmo [Geological Survey of Finland, Helsinki (Finland); Haelldahl, Lars [Hot Disk AB, Uppsala (Sweden)

    2003-04-01

    A strategy for a thermal site descriptive model of bedrock is under development at SKB. In the model different kinds of uncertainties exist. Some of these uncertainties are related to the potential errors in the methods used for determining thermal properties of rock. In two earlier investigations thermal properties of rock samples were analysed according to the TPS method (transient plane source). Thermal conductivity and thermal diffusivity were determined using the TPS method. For a comparison, the same samples have been measured at the Geological Survey of Finland (GSF), using different laboratory methods. In this later investigation, the thermal conductivity was determined using the divided-bar method and the specific heat capacity using a calorimetric method. The mean differences between the results of different methods are relatively low but the results of individual samples show large variations. The thermal conductivity measured by the divided bar method gives for most samples slightly higher values, in average about 3%, than the TPS method. The specific heat capacity measured by the calorimetric method gives lower values, in average about 2%, than the TPS method. Consequently, the thermal diffusivity calculated from thermal conductivity and specific heat capacity gives higher values, in average about 6%, than the TPS method. Reasons for the differences are estimated mainly to be dependent on differences between the samples, errors in the temperature dependence of specific heat and in the transformation from volumetric to specific heat. The TPS measurements are performed using two pieces (sub-samples) of rock. Only one of these two sub-samples was measured using the divided bar method and the calorimetric method. Further, sample preparation involved changes in the size of some of the samples. The mean differences between the results of different methods are within the margins of error reported by the measuring laboratories. However, systematic errors in

  8. Thermal properties of the Cobourg Limestone

    Science.gov (United States)

    Pitts, Michelle

    The underground storage of used nuclear fuel in Deep Geologic Repositories (DGRs) has been a subject of research in Canada for decades. One important technical aspect of repository design is the accommodation of the mechanical impacts of thermal inputs (heating) from the fuel as it goes through the remainder of its life cycle. Placement room spacing, a major factor in project cost, will be determined by the ability of the host rock to dissipate heat. The thermal conductivity and linear thermal expansion will determine the evolution of the temperature and thermally-induced stress fields. Thermal processes must be well understood to design a successful DGR. This thesis examines the thermal properties of rocks, how they are influenced by factors such as temperature, pressure, mineralogy, porosity, and saturation; and common methods for calculating and/or measuring these properties. A brief overview of thermal and thermally-coupled processes in the context of DGRs demonstrates the degree to which they would impact design, construction, and operation of these critical structures. Several case histories of major in situ heating experiments are reviewed to determine how the lessons learned could be applied to a Canadian Underground Demonstration Facility (UDF). A mineralogy investigation using X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) examines samples of the Cobourg Limestone from the Bowmanville and Bruce sites, and demonstrates geographical variability within the Cobourg Formation. The thermal properties of samples from the Bowmanville site are determined. A divided bar apparatus was constructed and used to measure thermal conductivity. The temperature measurement component of the divided bar apparatus was used to measure linear thermal expansion. Finally, the past investigations into the thermal impact of a DGR are reviewed, and the implications of the laboratory testing results on similar analyses are discussed.

  9. The EXTASE thermal probe: Laboratory investigation and modelling of thermal properties

    Science.gov (United States)

    Kaufmann, E.; Knollenberg, J.; Kargl, G.; Koemle, N. I.

    2011-10-01

    In recent years space missions including landing devices are getting more important. These missions allow in-situ measurements and lead therefore to information on the structure and behavior of extraterrestrial surface and subsurface layers. Sensors used for this kind of missions have to be adapted to the non-terrestrial environment conditions. The better the properties of the single elements of each sensor are known, the more precise are the results from the data evaluation of in-situ measurements. We present the results of thermal conductivity measurements and simulations done for the fiber compound tube used as structural element for the heating segments of the MUPUS-PEN and EXTASE - a spin-off project of Rosetta/MUPUS.

  10. Thermal remediation alters soil properties - a review.

    Science.gov (United States)

    O'Brien, Peter L; DeSutter, Thomas M; Casey, Francis X M; Khan, Eakalak; Wick, Abbey F

    2018-01-15

    Contaminated soils pose a risk to human and ecological health, and thermal remediation is an efficient and reliable way to reduce soil contaminant concentration in a range of situations. A primary benefit of thermal treatment is the speed at which remediation can occur, allowing the return of treated soils to a desired land use as quickly as possible. However, this treatment also alters many soil properties that affect the capacity of the soil to function. While extensive research addresses contaminant reduction, the range and magnitude of effects to soil properties have not been explored. Understanding the effects of thermal remediation on soil properties is vital to successful reclamation, as drastic effects may preclude certain post-treatment land uses. This review highlights thermal remediation studies that have quantified alterations to soil properties, and it supplements that information with laboratory heating studies to further elucidate the effects of thermal treatment of soil. Notably, both heating temperature and heating time affect i) soil organic matter; ii) soil texture and mineralogy; iii) soil pH; iv) plant available nutrients and heavy metals; v) soil biological communities; and iv) the ability of the soil to sustain vegetation. Broadly, increasing either temperature or time results in greater contaminant reduction efficiency, but it also causes more severe impacts to soil characteristics. Thus, project managers must balance the need for contaminant reduction with the deterioration of soil function for each specific remediation project. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Measurement of Thermal Properties of Growing Media for Green Roofs: Assessment of a Laboratory Procedure and Experimental Results

    Directory of Open Access Journals (Sweden)

    Benedetta Barozzi

    2017-10-01

    Full Text Available While the Italian standard UNI 11235:2015 establishes minimum performance criteria, the thermal resistance of the growing medium of green roofs is not included in national regulations. Instead, thermal transmittance limits for roofs are obtained by referring to other stratigraphic layers. In the absence of specific national and international standards for laboratory calculations of the thermal performance of growing media for green roofs, a multi-year laboratory testing campaign was carried out on 8 samples which aimed to define the thermal resistance reference values of growing media as a function of density and water content. Thermal conductivity varies between 0.046–0.179 W/mK for dry samples as a function of density and between 0.046–0.47 W/mK as a function of moisture content. Defining a reference method, laboratory tests and restitution of the output in performance curves, was based on 108 tests carried out according to and deviating from the standard based on both guarded hot plate and heat flow meter methods. The significance of the results has prompted researchers and industrial partners to engage in further investment and ongoing tests in this area, targeting the definition of a standard laboratory method to be presented worldwide.

  12. Measurement of thermal properties of soil and concrete samples

    DEFF Research Database (Denmark)

    Pagola, Maria Alberdi; Jensen, Rasmus Lund; Madsen, Søren

    February 2016 and February 2017. The presented work mainly consists of thermal property measurements. They become important as they form the basis for dimensioning a planned ground source heat pump installation based on closed loop vertical ground heat exchangers. This report complements the report......, the measurements of the properties of the concrete are treated. The work is extended in appendixes.......This document aims to present the laboratory work undertaken to analyse the thermal properties of the soil at two test sites in Denmark and the concrete produced by Centrum Pæle A/S, used to produce the pile heat exchangers studied in the present PhD project. The tasks have been carried out between...

  13. Soil/Rock Properties Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Soil/Rock Properties LaboratoryLocation: Spokane SiteThe Soil/Rock Properties Laboratory is contained in the soils bay, a 4,700 sq. ft. facility that provides space...

  14. Research on technology of evaluating thermal property data of nuclear power materials

    International Nuclear Information System (INIS)

    Imai, Hidetaka; Baba, Tetsuya; Matsumoto, Tsuyoshi; Kishimoto, Isao; Taketoshi, Naoyuki; Arai, Teruo

    1997-01-01

    For the materials of first wall and diverter of nuclear fusion reactor, in order to withstand steady and unsteady high heat flux load, excellent thermal characteristics are required. It is strongly demanded to measure such thermal property values as heat conductivity, heat diffusivity, specific heat capacity, emissivity and so using small test pieces up to higher than 2000degC. As the materials of nuclear reactors are subjected to neutron irradiation, in order to secure the long term reliability of the materials, it is very important to establish the techniques for forecasting the change of the thermal property values due to irradiation effect. Also the establishment of the techniques for estimating the thermal property values of new materials like low radioactivation material is important. In National Research Laboratory of Metrology, the research on the advancement of the measuring technology for high temperature thermal properties has resulted in the considerably successful development of such technologies. In this research, the rapid measurement of thermal property values up to superhigh temperature with highest accuracy, the making of thermal property data set of high level, the analysis and evaluation of the correlation of material characters and thermal property values, and the development of the basic techniques for estimating the thermal property values of solid materials are aimed at and advanced. These are explained. (K.I.)

  15. Rock properties and their effect on thermally-induced displacements and stresses

    International Nuclear Information System (INIS)

    Chan, T.; Hood, M.; Board, M.

    1980-02-01

    A discussion is given of the importance of material properties in the finite-element calculations for thermally induced displacements and stresses resulting from a heating experiment in an in-situ granitic rock, at Stripa, Sweden. Comparisons are made between field measurements and finite element method calculations using (1) temperature independent, (2) temperature dependent thermal and thermomechanical properties and (3) in-situ and laboratory measurements for Young's modulus. The calculations of rock displacements are influenced predominantly by the temperature dependence of the thermal expansion coefficient, whereas the dominant factor affecting predictions for rock stresses is the in-situ modulus

  16. Thermal properties of bentonite under extreme conditions

    Energy Technology Data Exchange (ETDEWEB)

    Vasicek, R. [Czech Technical Univ., Centre of Experimental Geotechnics, Faculty of Civil Engineering, Prague (Czech Republic)

    2005-07-01

    Centre of Experimental Geotechnics (CEG) deals with the research of the behaviour of bentonite and clays. The measurement of thermal properties is not so frequent test in geotechnical laboratory but in relation to deep repository it is a part which should not be overlooked. The reason is the heat generated by canister with spent nuclear fuel and possible influence of the heat on the materials of the engineered barrier. In the initial stages following the burial of canister with the waste the barrier materials will be exposed to elevated temperature. According to existing information, these temperatures should not exceed 90 C. That heat can induce a creation of cracks and opening of joint between highly compacted blocks. It will predispose the bentonite barrier to penetration of water from surrounding towards to canister. Therefore easy removal of heat through the barrier is required. It is essential that the tests aimed at determining the real values of measured parameters are carried out in conditions identical with those anticipated in a future disposal system. These relatively complicated thermophysical tests are logical continuation of the simple ones, carried out under laboratory temperature and on not fully saturated samples without possibility to measure the swelling pressure. Thermophysical properties and swelling pressure are dominantly influenced by water content (which is influenced by temperature). Therefore is important to realize the tests under different moisture and thermal conditions. These tests are running at the APT-PO1 Analyser, designed to fulfill mentioned requirements - it allows measurement of thermal properties under temperature up to 200 C and swelling pressure up to 20 MPa. The device is capable to register the evolution of temperature, swelling and vapor pressure. The measurement of thermal conductivity and volume heat capacity is realized by the dynamic impulse method with point source of heat. Four types of tests are possible: at

  17. Laboratory analysis of soil hydraulic properties of TA-49 soil samples. Volume I: Report summary

    International Nuclear Information System (INIS)

    1995-04-01

    The Hydrologic Testing Laboratory at Daniel B. Stephens ampersand Associates, Inc. (DBS ampersand A) has completed laboratory tests on TA-49 soil samples as specified by Mr. Daniel A. James and summarized in Table 1. Tables 2 through 12 give the results of the specified analyses. Raw laboratory data and graphical plots of data (where appropriate) are contained in Appendices A through K. Appendix L lists the methods used in these analyses. A detailed description of each method is available upon request. Thermal properties were calculated using methods reviewed by Campbell and covered in more detail in Appendix K. Typically, soil thermal conductivities are determined using empirical fitting parameters (five in this case), Some assumptions are also made in the equations used to reduce the raw data. In addition to the requested thermal property measurements, calculated values are also presented as the best available internal check on data quality. For both thermal conductivities and specific heats, calculated and measured values are consistent and the functions often cross. Interestingly, measured thermal conductivities tend to be higher than calculated thermal conductivities around typically encountered in situ moisture contents (±5 percent). While we do not venture an explanation of the difference, sensitivity testing of any problem requiring nonisothermal modeling across this range is in order

  18. Naturally cured foamed concrete with improved thermal insulation properties

    Directory of Open Access Journals (Sweden)

    Mashkin Nikolay

    2018-01-01

    Full Text Available The paper is dedicated to investigation on improvement of thermal insulation properties of non-autoclaved concrete by increasing aggregate stability of foamed concrete mixture. The study demonstrates influence of mineral admixtures on the foam stability index in the mortar mixture and on decrease of foamed concrete density and thermal conductivity. The effect of mineral admixtures on thermal conductivity properties of non-autoclaved concrete was assessed through different ways of their addition: to the foam and to the mortar mixture. The admixtures were milled up to the specific surface area of 300 and 600 m2/kg using an AГO-9 centrifugal attrition mill with continuous operation mode (Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk. Laboratory turbulent foam concrete mixer was used to prepare foamed concrete. Thermal conductivity coefficient was defined by a quick method using “ИTП-MГ 4 “Zond” thermal conductivity meter in accordance with the regulatory documents. The impact of modifiers on the foam structure stability was defined using the foam stability index for the mortar mixture. The research demonstrated the increase in stability of porous structure of non-autoclaved concrete when adding wollastonite and diopside. Improvement of thermal and physical properties was demonstrated, the decrease of thermal conductivity coefficient reaches 0.069 W/(m×°C

  19. Evaluation of the basic mechanical and thermal properties of deep crystalline rocks

    International Nuclear Information System (INIS)

    Park, Byoung Yoon; Bae, Dae Seok; Kim, Chun Soo; Kim, Kyung Su; Koh, Young Kwon; Jeon, Seok Won

    2001-04-01

    This report provides the mechanical and thermal properties of granitic intact rocks obtained from Deep Core Drilling Program which is carried out as part of the assessment of deep geological environmental condition. These data are the basic material properties of the core samples from the boreholes drilled up to 500 m depth at the Yusung and Kosung sites. These sites were selected based on the result of preliminary site evaluation study. In this study, the mechanical properties include density, porosity, P-wave velocity, S-wave velocity, uniaxial compressive strength, Young's modulus, Poisson's ratio, tensile strength, and shear strength of fractures, and the thermal properties are heat conductivity, thermal expansion coefficient, specific heat and so on. Those properties were measured through laboratory tests and these data are compared with the existing test results of several domestic rocks

  20. Evaluation of the basic mechanical and thermal properties of deep crystalline rocks

    Energy Technology Data Exchange (ETDEWEB)

    Park, Byoung Yoon; Bae, Dae Seok; Kim, Chun Soo; Kim, Kyung Su; Koh, Young Kwon; Jeon, Seok Won

    2001-04-01

    This report provides the mechanical and thermal properties of granitic intact rocks obtained from Deep Core Drilling Program which is carried out as part of the assessment of deep geological environmental condition. These data are the basic material properties of the core samples from the boreholes drilled up to 500 m depth at the Yusung and Kosung sites. These sites were selected based on the result of preliminary site evaluation study. In this study, the mechanical properties include density, porosity, P-wave velocity, S-wave velocity, uniaxial compressive strength, Young's modulus, Poisson's ratio, tensile strength, and shear strength of fractures, and the thermal properties are heat conductivity, thermal expansion coefficient, specific heat and so on. Those properties were measured through laboratory tests and these data are compared with the existing test results of several domestic rocks.

  1. Thermal Properties of G-348 Graphite

    Energy Technology Data Exchange (ETDEWEB)

    McEligot, Donald M. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Swank, W. David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cottle, David L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Valentin, Francisco I. [City Univ. (CUNY), NY (United States)

    2017-04-01

    Fundamental measurements have been obtained in the INL Graphite Characterization Laboratory to deduce the temperature dependence of thermal conductivity for G-348 isotropic graphite, which has been used by City College of New York in thermal experiments related to gas-cooled nuclear reactors. Measurements of thermal diffusivity, mass, volume and thermal expansion were converted to thermal conductivity in accordance with ASTM Standard Practice C781-08 (R-2014). Data are tabulated and a preliminary correlation for the thermal conductivity is presented as a function of temperature from laboratory temperature to 1000C.

  2. A study on the thermal and mechanical properties of inconel for steam generator U-tube

    International Nuclear Information System (INIS)

    Ryu, Woo Seong; Kang, Young Hwan; Park, Jong Man; Choo, Kee Nam; Kim, Sung Soo; Maeng, Wan Young; Park, Se Jin

    1993-12-01

    A series of laboratory tests was conducted to obtain the thermal and mechanical properties of Inconel 600 and 690 for the design document of steam generator U-tube. The following properties were measured as a function of temperature, and treated statistically to establish a database: 1) heat capacity, RT ∼ 500 deg C, 2) thermal expansion, RT ∼ 500 deg C, 3) thermal diffusivity, RT ∼ 500 deg C, 4) thermal conductivity, RT ∼ 500 deg C, 5) tensile property, RT ∼ 700 deg C 6) ductility, RT ∼ 700 deg C, 7) Elastic modulii and Poission's ratio, RT, 8) Microhardness, 9) Oxidation rate. (Author)

  3. Prediction of Geomechanical Properties from Thermal Conductivity of Low-Permeable Reservoirs

    Science.gov (United States)

    Chekhonin, Evgeny; Popov, Evgeny; Popov, Yury; Spasennykh, Mikhail; Ovcharenko, Yury; Zhukov, Vladislav; Martemyanov, Andrey

    2016-04-01

    A key to assessing a sedimentary basin's hydrocarbon prospect is correct reconstruction of thermal and structural evolution. It is impossible without adequate theory and reliable input data including among other factors thermal and geomechanical rock properties. Both these factors are also important in geothermal reservoirs evaluation and carbon sequestration problem. Geomechanical parameters are usually estimated from sonic logging and rare laboratory measurements, but sometimes it is not possible technically (low quality of the acoustic signal, inappropriate borehole and mud conditions, low core quality). No wonder that there are attempts to correlate the thermal and geomechanical properties of rock, but no one before did it with large amount of high quality thermal conductivity data. Coupling results of sonic logging and non-destructive non-contact thermal core logging opens wide perspectives for studying a relationship between the thermal and geomechanical properties. More than 150 m of full size cores have been measured at core storage with optical scanning technique. Along with results of sonic logging performed with Sonic Scanner in different wells drilled in low permeable formations in West Siberia (Russia) it provided us with unique data set. It was established a strong correlation between components of thermal conductivity (measured perpendicular and parallel to bedding) and compressional and shear acoustic velocities in Bazhen formation. As a result, prediction of geomechanical properties via thermal conductivity data becomes possible, corresponding results was demonstrated. The work was supported by the Russian Ministry of Education and Science, project No. RFMEFI58114X0008.

  4. Thermal properties of methane hydrate by experiment and modeling and impacts upon technology

    Energy Technology Data Exchange (ETDEWEB)

    Warzinski, R.P.; Gamwo, I.K.; Rosenbaum, E.J. [United States Dept. of Energy, Pittsburgh, PA (United States). National Energy Technology Laboratory; Myshakin, E.M. [NETL Support Contractor, South Park, PA (United States); Jiang, H.; Jordan, K.D. [Pittsburgh Univ., Pittsburgh, PA (United States). Dept. of Chemistry; English, N.J. [Dublin University College, Dublin (Ireland). Conway Inst. of Biomolecular and Biomedical Research, Centre for Synthesis and Chemical Biology; Shaw, D.W. [Geneva College, Beaver Falls, PA (United States). Dept. of Engineering

    2008-07-01

    The current hydrate research at the National Energy Technology Laboratory (NETL) involves both experimental and theoretical work on developing models and methods for predicting the behaviour of gas hydrates in their natural environment under production of climate change scenarios. The modeling efforts include both fundamental and reservoir scale simulations and economic modeling. The thermal properties of methane hydrate are important for hydrate production, seafloor stability and climate change scenarios. A new experimental technique and advanced molecular dynamics simulation (MDS) have determined the thermal properties of pure methane hydrate under conditions similar to naturally occurring hydrate-bearing sediments. The thermal conductivity and thermal diffusivity values of low-porosity methane hydrate formed in the laboratory were measured using an innovative single-sided, Transient Plane Source (TPS) technique. The results were in good agreement with results from an equilibrium MDS method using in-plane polarization of the water molecules. MDS was also performed using a non-equilibrium model with a fully polarizable force field for water. The Tough+Hydrate reservoir simulator was also used to evaluate the impact of thermal conductivity on gas production from a hydrate-bearing reservoir. 42 refs., 1 tab., 5 figs.

  5. Numerical analysis of thermal impact on hydro-mechanical properties of clay

    Directory of Open Access Journals (Sweden)

    Xuerui Wang

    2014-10-01

    Full Text Available As is known, high-level radioactive waste (HLW is commonly heat-emitting. Heat output from HLW will dissipate through the surrounding rocks and induce complex thermo-hydro-mechanical-chemical (THMC processes. In highly consolidated clayey rocks, thermal effects are particularly significant because of their very low permeability and water-saturated state. Thermal impact on the integrity of the geological barriers is of most importance with regard to the long-term safety of repositories. This study focuses on numerical analysis of thermal effects on hydro-mechanical properties of clayey rock using a coupled thermo-mechanical multiphase flow (TH2M model which is implemented in the finite element programme OpenGeoSys (OGS. The material properties of the numerical model are characterised by a transversal isotropic elastic model based on Hooke's law, a non-isothermal multiphase flow model based on van Genuchten function and Darcy's law, and a transversal isotropic heat transport model based on Fourier's law. In the numerical approaches, special attention has been paid to the thermal expansion of three different phases: gas, fluid and solid, which could induce changes in pore pressure and porosity. Furthermore, the strong swelling and shrinkage behaviours of clayey material are also considered in the present model. The model has been applied to simulate a laboratory heating experiment on claystone. The numerical model gives a satisfactory representation of the observed material behaviour in the laboratory experiment. The comparison of the calculated results with the laboratory findings verifies that the simulation with the present numerical model could provide a deeper understanding of the observed effects.

  6. PETher - Physical Properties of Thermal Water under In-situ-Conditions

    Science.gov (United States)

    Herfurth, Sarah; Schröder, Elisabeth

    2016-04-01

    The objective of PETher, a research project funded by the German Federal Ministry for Economic Affairs and Energy (BMWi), is to experimentally determine thermo-physical properties (specific isobaric heat capacity, kinematic viscosity, density and thermal conductivity) of geothermal water in-situ-conditions (pressure, temperature, chemical composition including gas content of the brine) present in geothermal applications. Knowing these thermo-physical properties reduces the uncertainties with respect to estimating the thermal output and therefore the economic viability of the power plant. Up to now, only a limited number of measurements of selected physical properties have been made, usually under laboratory conditions and for individual geothermal plants. In-situ measured parameters, especially in the temperature range of 120°C and higher, at pressures of 20 bar and higher, as well as with a salinity of up to 250 g/l, are sparse to non-existing. Therefore, pure water properties are often used as reference data and for designing the power plant and its components. Currently available numerical models describing the thermo-physical properties are typically not valid for the conditions in geothermal applications and do not consider the substantial influence of the chemical composition of the thermal water. Also, actual geothermal waters have not been subject of detailed measurements systematically performed under operational conditions on a large-scale basis. Owing to the lack of reliable data, a validation of numerical models for investigating geothermal systems is not possible. In order to determine the dependency of the thermo-physical properties of geothermal water on temperature, pressure and salinity in-situ measurements are conducted. The measurements are taking place directly at several geothermal applications located in Germany's hydrogeothermal key regions. In order to do this, a mobile testing unit was developed and refined with instruments specifically

  7. Thermal-Insulation Properties of Multilayer Textile Packages

    Directory of Open Access Journals (Sweden)

    Matusiak Małgorzata

    2014-12-01

    Full Text Available Thermal-insulation properties of textile materials play a significant role in material engineering of protective clothing. Thermal-insulation properties are very important from the point of view of thermal comfort of the clothing user as well as the protective efficiency against low or high temperature. Thermal protective clothing usually is a multilayer construction. Its thermal insulation is a resultant of a number of layers and their order, as well as the thermalinsulation properties of a single textile material creating particular layers. The aim of the presented work was to investigate the relationships between the thermal-insulation properties of single materials and multilayer textile packages composed of these materials. Measurement of the thermal-insulation properties of single and multilayer textile materials has been performed with the Alambeta. The following properties have been investigated: thermal conductivity, resistance and absorptivity. Investigated textile packages were composed of two, three and four layers made of woven and knitted fabrics, as well as nonwovens. On the basis of the obtained results an analysis has been carried out in order to assess the dependency of the resultant values of the thermal-insulation properties of multilayer packages on the appropriate values of particular components.

  8. Mars Science Laboratory Rover System Thermal Test

    Science.gov (United States)

    Novak, Keith S.; Kempenaar, Joshua E.; Liu, Yuanming; Bhandari, Pradeep; Dudik, Brenda A.

    2012-01-01

    On November 26, 2011, NASA launched a large (900 kg) rover as part of the Mars Science Laboratory (MSL) mission to Mars. The MSL rover is scheduled to land on Mars on August 5, 2012. Prior to launch, the Rover was successfully operated in simulated mission extreme environments during a 16-day long Rover System Thermal Test (STT). This paper describes the MSL Rover STT, test planning, test execution, test results, thermal model correlation and flight predictions. The rover was tested in the JPL 25-Foot Diameter Space Simulator Facility at the Jet Propulsion Laboratory (JPL). The Rover operated in simulated Cruise (vacuum) and Mars Surface environments (8 Torr nitrogen gas) with mission extreme hot and cold boundary conditions. A Xenon lamp solar simulator was used to impose simulated solar loads on the rover during a bounding hot case and during a simulated Mars diurnal test case. All thermal hardware was exercised and performed nominally. The Rover Heat Rejection System, a liquid-phase fluid loop used to transport heat in and out of the electronics boxes inside the rover chassis, performed better than predicted. Steady state and transient data were collected to allow correlation of analytical thermal models. These thermal models were subsequently used to predict rover thermal performance for the MSL Gale Crater landing site. Models predict that critical hardware temperatures will be maintained within allowable flight limits over the entire 669 Sol surface mission.

  9. The thermal and mechanical properties of a low-density glass-fiber-reinforced elastomeric ablation material

    Science.gov (United States)

    Engelke, W. T.; Robertson, R. W.; Bush, A. L.; Pears, C. D.

    1974-01-01

    An evaluation of the thermal and mechanical properties was performed on a molded low-density elastomeric ablation material designated as Material B. Both the virgin and charred states were examined to provide meaningful inputs to the design of a thermal protection system. Chars representative of the flight chars formed during ablation were prepared in a laboratory furnace from 600 K to 1700 K and properties of effective thermal conductivity, heat capacity, porosity and permeability were determined on the furnace chars formed at various temperature levels within the range. This provided a boxing of the data which will enable the prediction of the transient response of the material during flight ablation.

  10. Evaluation of properties and thermal stress field for thermal barrier coatings

    Institute of Scientific and Technical Information of China (English)

    王良; 齐红宇; 杨晓光; 李旭

    2008-01-01

    In order to get thermal stress field of the hot section with thermal barrier coating (TBCs), the thermal conductivity and elastic modulus of top-coat are the physical key properties. The porosity of top-coat was tested and evaluated under different high temperatures. The relationship between the microstructure (porosity of top-coat) and properties of TBCs were analyzed to predict the thermal properties of ceramic top-coat, such as thermal conductivity and elastic modulus. The temperature and stress field of the vane with TBCs were simulated using two sets of thermal conductivity data and elastic modulus, which are from literatures and this work, respectively. The results show that the temperature and stress distributions change with thermal conductivity and elastic modulus. The differences of maximum temperatures and stress are 6.5% and 8.0%, respectively.

  11. Thermal property testing technique on micro specimen

    International Nuclear Information System (INIS)

    Baba, Tetsuya; Kishimoto, Isao; Taketoshi, Naoyuki

    2000-01-01

    This study aims at establishment of further development on some testing techniques on the nuclear advanced basic research accumulated by the National Research Laboratory of Metrology for ten years. For this purpose, a technology to test heat diffusion ratio and specific heat capacity of less than 3 mm in diameter and 1 mm in thickness of micro specimen and technology to test heat diffusion ratio at micro area of less than 1 mm in area along cross section of less than 10 mm in diameter of column specimen were developed to contribute to common basic technology supporting the nuclear power field. As a result, as an element technology to test heat diffusion ratio and specific heat capacity of the micro specimen, a specimen holding technique stably to hold a micro specimen with 3 mm in diameter could be developed. And, for testing the specific heat capacity by using the laser flush differential calorimetry, a technique to hold two specimen of 5 mm in diameter at their proximities was also developed. In addition, by promoting development of thermal property data base capable of storing thermal property data obtained in this study and with excellent workability in this 1998 fiscal year a data in/out-put program with graphical user interface could be prepared. (G.K.)

  12. Effect of carbon black on thermal properties of charcoal and salacca leafstalk briquettes

    Science.gov (United States)

    Thassana, Chewa; Nuleg, Witoon

    2017-08-01

    In this work, the effect of a carbon black (CB) on the thermal properties of briquettes produced from the charcoal and the salacca leafstalk with and without CB have been investigated. Four thermal properties of a briquettes compose of the burning time, the calorific value, the percentage moisture (PMC) and an percentage ash content (PAC) were analyzed using standard laboratory methods. Our results were indicated that the sallacca leafstalk mix a carbon black is the long burning times, high heating but a few ash content. Results shown that the burning time and the calorific value of a charcoal, a charcoal with CB, the salacca leafstalk and the salacca leafstalk with carbon black particles is about 58, 63, 76, 81 minutes, and 10.33, 12.96, 13.12, 14.63 MJ/kg, respectively. In addition, the PMC and PAC were in range of 11.6 - 8.14% and 9.33 - 5.42%. So, we can conclude that a cabon black affect on the thermal properties of a briquettes and salacca leaftstalk mixed CB has been most suited for briquetting.

  13. Thermal Properties and Thermal Analysis:

    Science.gov (United States)

    Kasap, Safa; Tonchev, Dan

    The chapter provides a summary of the fundamental concepts that are needed to understand the heat capacity C P, thermal conductivity κ, and thermal expansion coefficient α L of materials. The C P, κ, and α of various classes of materials, namely, semiconductors, polymers, and glasses, are reviewed, and various typical characteristics are summarized. A key concept in crystalline solids is the Debye theory of the heat capacity, which has been widely used for many decades for calculating the C P of crystals. The thermal properties are interrelated through Grüneisen's theorem. Various useful empirical rules for calculating C P and κ have been used, some of which are summarized. Conventional differential scanning calorimetry (DSC) is a powerful and convenient thermal analysis technique that allows various important physical and chemical transformations, such as the glass transition, crystallization, oxidation, melting etc. to be studied. DSC can also be used to obtain information on the kinetics of the transformations, and some of these thermal analysis techniques are summarized. Temperature-modulated DSC, TMDSC, is a relatively recent innovation in which the sample temperature is ramped slowly and, at the same time, sinusoidally modulated. TMDSC has a number of distinct advantages compared with the conventional DSC since it measures the complex heat capacity. For example, the glass-transition temperature T g measured by TMDSC has almost no dependence on the thermal history, and corresponds to an almost step life change in C P. The new Tzero DSC has an additional thermocouple to calibrate better for thermal lags inherent in the DSC measurement, and allows more accurate thermal analysis.

  14. Graphene Thermal Properties: Applications in Thermal Management and Energy Storage

    Directory of Open Access Journals (Sweden)

    Jackie D. Renteria

    2014-11-01

    Full Text Available We review the thermal properties of graphene, few-layer graphene and graphene nanoribbons, and discuss practical applications of graphene in thermal management and energy storage. The first part of the review describes the state-of-the-art in the graphene thermal field focusing on recently reported experimental and theoretical data for heat conduction in graphene and graphene nanoribbons. The effects of the sample size, shape, quality, strain distribution, isotope composition, and point-defect concentration are included in the summary. The second part of the review outlines thermal properties of graphene-enhanced phase change materials used in energy storage. It is shown that the use of liquid-phase-exfoliated graphene as filler material in phase change materials is promising for thermal management of high-power-density battery parks. The reported experimental and modeling results indicate that graphene has the potential to outperform metal nanoparticles, carbon nanotubes, and other carbon allotropes as filler in thermal management materials.

  15. Calculation of experiment uncertainty in laboratory determination of several geoengineering properties of tuffs from Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Nimick, F.B.; Schwartz, B.M.; Price, R.H.

    1991-11-01

    A method for estimating the precision and accuracy of measured parameters is described. Examples of application of the estimating method are presented for density, porosity, compressive strength, Young's modulus, Poisson's ratio, and thermal expansion. With the exception of the coefficient of linear thermal expansion, all laboratory data for these properties for tuff samples appear to have reasonable experiment uncertainties. Uncertainties in the thermal-expansion coefficients may be as high as 39% of the values, although most uncertainties for the coefficients are probably ≤2%. 4 refs., 1 fig., 15 tabs

  16. Thermal properties of heterogeneous fuels

    International Nuclear Information System (INIS)

    Staicu, D.; Beauvy, M.

    1998-01-01

    Fresh or irradiated nuclear fuels are composites or solid solutions more or less heterogeneous, and their thermal conductivities are strongly dependent on the microstructure. The effective thermal conductivities of these heterogeneous solids must be determined for the modelling of the behaviour under irradiation. Different methods (analytical or numerical) published in the literature can be used for the calculation of this effective thermal conductivity. They are analysed and discussed, but finally only few of them are really useful because the assumptions selected are often not compatible with the complex microstructures observed in the fuels. Numerical calculations of the effective thermal conductivity of various fuels based on the microstructure information provided in our laboratory by optical microscopy or electron micro-probe analysis images, have been done for the validation of these methods. The conditions necessary for accurate results on effective thermal conductivity through these numerical calculations are discussed. (author)

  17. Non-Contact Thermal Properties Measurement with Low-Power Laser and IR Camera System

    Science.gov (United States)

    Hudson, Troy L.; Hecht, Michael H.

    2011-01-01

    As shown by the Phoenix Mars Lander's Thermal and Electrical Conductivity Probe (TECP), contact measurements of thermal conductivity and diffusivity (using a modified flux-plate or line-source heat-pulse method) are constrained by a number of factors. Robotic resources must be used to place the probe, making them unavailable for other operations for the duration of the measurement. The range of placement is also limited by mobility, particularly in the case of a lander. Placement is also subject to irregularities in contact quality, resulting in non-repeatable heat transfer to the material under test. Most important from a scientific perspective, the varieties of materials which can be measured are limited to unconsolidated or weakly-cohesive regolith materials, rocks, and ices being too hard for nominal insertion strengths. Accurately measuring thermal properties in the laboratory requires significant experimental finesse, involving sample preparation, controlled and repeatable procedures, and, practically, instrumentation much more voluminous than the sample being tested (heater plates, insulation, temperature sensors). Remote measurements (infrared images from orbiting spacecraft) can reveal composite properties like thermal inertia, but suffer both from a large footprint (low spatial resolution) and convolution of the thermal properties of a potentially layered medium. In situ measurement techniques (the Phoenix TECP is the only robotic measurement of thermal properties to date) suffer from problems of placement range, placement quality, occupation of robotic resources, and the ability to only measure materials of low mechanical strength. A spacecraft needs the ability to perform a non-contact thermal properties measurement in situ. Essential components include low power consumption, leveraging of existing or highly-developed flight technologies, and mechanical simplicity. This new in situ method, by virtue of its being non-contact, bypasses all of these

  18. Thermal properties variations in unconsolidated material for very shallow geothermal application (ITER project)

    Science.gov (United States)

    Sipio, Eloisa Di; Bertermann, David

    2018-04-01

    In engineering, agricultural and meteorological project design, sediment thermal properties are highly important parameters, and thermal conductivity plays a fundamental role when dimensioning ground heat exchangers, especially in very shallow geothermal systems. Herein, the first 2 m of depth from surface is of critical importance. However, the heat transfer determination in unconsolidated material is difficult to estimate, as it depends on several factors, including particle size, bulk density, water content, mineralogy composition and ground temperature. The performance of a very shallow geothermal system, as a horizontal collector or heat basket, is strongly correlated to the type of sediment at disposal and rapidly decreases in the case of dry-unsaturated conditions. The available experimental data are often scattered, incomplete and do not fully support thermo-active ground structure modeling. The ITER project, funded by the European Union, contributes to a better knowledge of the relationship between thermal conductivity and water content, required for understanding the very shallow geothermal systems behaviour in saturated and unsaturated conditions. So as to enhance the performance of horizontal geothermal heat exchangers, thermally enhanced backfilling material were tested in the laboratory, and an overview of physical-thermal properties variations under several moisture and load conditions for different mixtures of natural material was here presented.

  19. New approaches in the indirect quantification of thermal rock properties in sedimentary basins: the well-log perspective

    DEFF Research Database (Denmark)

    Fuchs, Sven; Balling, Niels; Förster, Andrea

    Numerical temperature models generated for geodynamic studies as well as for geothermal energy solutions heavily depend on rock thermal properties. Best practice for the determination of those parameters is the measurement of rock samples in the laboratory. Given the necessity to enlarge databases...

  20. Thermal properties of clay-based buffer materials for a nuclear fuel waste disposal vault

    International Nuclear Information System (INIS)

    Radhakrishna, H.S.

    1984-06-01

    The thermal properties of three types of bentonite clay, one illite-rich shale and one kaolin mixed with crushed granite were investigated. Thermal conductivity measurements were made over a range of mix proportions, moisture content, density and ambient temperature using the transient heat-probe method. The effects of thermal drying in the buffer zone prior to water uptake were investigated by means of laboratory-scale heater experiments. Illite-rich shale (Sealbond) and kaolin exhibited better compactability and thermal conductivity than the bentonite clays. The thermal conductivity of all types of clay buffers showed a high degree of moisture dependency and relatively no effect due to elevated temperature under high fluid pressure conditions. Bentonite buffers compacted to a dry density of 1200 to 1400 kg/m 3 showed extensive cracking due to differential shrinkage. Addition of crushed granite, and/or compaction to a higher density, reduced the thermal cracking of the buffer material

  1. Thermal Shock Property of Al/Ni-ZrO2 Gradient Thermal Barrier Coatings

    Institute of Scientific and Technical Information of China (English)

    FANJin-juan; WANGQuan-sheng; ZHANGWei-fang

    2004-01-01

    Al/Ni-ZrO2 gradient thermal barrier coatings are made on aluminum substrate using plasma spraying method and one direction thermal shock properties of the coatings are studied in this paper. The results show that pores in coatings link to form cracks vertical to coating surface. They go through the whole ZrO2 coating once vertical cracks form. When thermal shock cycles increase, horizontal cracks that result in coatings failure forms in the coatings and interface. And vertical cracks delay appearance of horizontal cracks and enhance thermal shock property of coatings. Failure mechanisms of coating thermal shock are discussed using experiments and finite element method.

  2. Thermal degradation of ethanolic biodiesel: Physicochemical and thermal properties evaluation

    International Nuclear Information System (INIS)

    Silva, Wellington Costa; Castro, Maria Priscila Pessanha; Perez, Victor Haber; Machado, Francisco A.; Mota, Leonardo; Sthel, Marcelo Silva

    2016-01-01

    The aim of this paper was to study the thermal degradation of soybean biodiesel attained by ethanolic route. The soybean biodiesel samples were subjected to heating treatment at 150 °C for 24 h in a closed oven under controlled atmosphere. During the experiments, samples were withdrawn at intervals of 3, 6, 9, 12, 15 and 24 h for physicochemical and thermophysical properties analysis. The biodiesel degradation was validated by Thermogravimetric analysis since their profiles for control and treated biodiesel were different. Also, "1H NMR confirmed this result due to a significant reduction at the signals related to the "1H located near to the double bonds in the unsaturated ethyl esters in agreement with an iodine index reduction and viscosity increase observed during degradation. Nevertheless, degraded biodiesel, under study conditions, preserved its thermophysical properties. These results may be relevant to qualify the produced biodiesel quality and collect physicochemical and thermophysical data important for applications in combustion studies including project of fuel injection systems. - Highlights: • Soybean biodiesel from ethanolic route was subjected to thermal degradation to verify its stability. • Thermal degradation of biodiesel was correlated with physicochemical properties. • Thermal effusivity, diffusivity and conductivity were estimate by photothermal techniques.

  3. Structural, optical and thermal properties of nanoporous aluminum

    International Nuclear Information System (INIS)

    Ghrib, Taher

    2015-01-01

    Highlights: • A simple electrochemical technique is presented and used to manufacture a porous aluminum layer. • Manufactured pores of 40 nm diameter and 200 nm depth are filled by nanocrystal of silicon and graphite. • Dimensions of pores increase with the anodization current which ameliorate the optical and thermal properties. • A new thermal method is presented which permit to determine the pores density and the layer thickness. • All properties show that the manufactured material can be used with success in solar cells. - Abstract: In this work the structural, thermal and optical properties of porous aluminum thin film formed with various intensities of anodization current in sulfuric acid are highlighted. The obtained pores at the surface are filled by sprayed graphite and nanocrystalline silicon (nc-Si) thin films deposited by plasma enhancement chemical vapor deposition (PECVD) which the role is to improve its optical and thermal absorption giving a structure of an assembly of three different media such as deposited thin layer (graphite or silicon)/(porous aluminum layer filled with the deposited layer)/(Al sample). The effect of anodization current on the microstructure of porous aluminum and the effect of the deposited layer were systematically studied by atomic force microscopy (AFM), transmission electron microscopy (TEM) and Raman spectroscopy. The thermal properties such as the thermal conductivity (K) and thermal diffusivity (D) are determined by the photothermal deflection (PTD) technique which is a non destructive technique. Based on this full characterization, it is demonstrated that the thermal and optical characteristics of these films are directly correlated to their micro-structural properties

  4. Boron nitride elastic and thermal properties. Irradiation effects

    International Nuclear Information System (INIS)

    Jager, Bernard.

    1977-01-01

    The anisotropy of boron nitride (BN) and especially thermal and elastic properties were studied. Specific heat and thermal conductivity between 1.2 and 300K, thermal conductivity between 4 and 350K and elastic constants C 33 and C 44 were measured. BN was irradiated with electrons at 77K and with neutrons at 27K to determine properties after irradiation [fr

  5. Thermal Transport Properties of Dry Spun Carbon Nanotube Sheets

    Directory of Open Access Journals (Sweden)

    Heath E. Misak

    2016-01-01

    Full Text Available The thermal properties of carbon nanotube- (CNT- sheet were explored and compared to copper in this study. The CNT-sheet was made from dry spinning CNTs into a nonwoven sheet. This nonwoven CNT-sheet has anisotropic properties in in-plane and out-of-plane directions. The in-plane direction has much higher thermal conductivity than the out-of-plane direction. The in-plane thermal conductivity was found by thermal flash analysis, and the out-of-plane thermal conductivity was found by a hot disk method. The thermal irradiative properties were examined and compared to thermal transport theory. The CNT-sheet was heated in the vacuum and the temperature was measured with an IR Camera. The heat flux of CNT-sheet was compared to that of copper, and it was found that the CNT-sheet has significantly higher specific heat transfer properties compared to those of copper. CNT-sheet is a potential candidate to replace copper in thermal transport applications where weight is a primary concern such as in the automobile, aircraft, and space industries.

  6. Thermal analysis of annular fins with temperature-dependent thermal properties

    Institute of Scientific and Technical Information of China (English)

    I. G. AKSOY

    2013-01-01

    The thermal analysis of the annular rectangular profile fins with variable thermal properties is investigated by using the homotopy analysis method (HAM). The thermal conductivity and heat transfer coefficient are assumed to vary with a linear and power-law function of temperature, respectively. The effects of the thermal-geometric fin parameter and the thermal conductivity parameter variations on the temperature distribution and fin efficiency are investigated for different heat transfer modes. Results from the HAM are compared with numerical results of the finite difference method (FDM). It can be seen that the variation of dimensionless parameters has a significant effect on the temperature distribution and fin efficiency.

  7. Towards standardized testing methodologies for optical properties of components in concentrating solar thermal power plants

    Science.gov (United States)

    Sallaberry, Fabienne; Fernández-García, Aránzazu; Lüpfert, Eckhard; Morales, Angel; Vicente, Gema San; Sutter, Florian

    2017-06-01

    Precise knowledge of the optical properties of the components used in the solar field of concentrating solar thermal power plants is primordial to ensure their optimum power production. Those properties are measured and evaluated by different techniques and equipment, in laboratory conditions and/or in the field. Standards for such measurements and international consensus for the appropriate techniques are in preparation. The reference materials used as a standard for the calibration of the equipment are under discussion. This paper summarizes current testing methodologies and guidelines for the characterization of optical properties of solar mirrors and absorbers.

  8. Thermal properties of selected cheeses samples

    Directory of Open Access Journals (Sweden)

    Monika BOŽIKOVÁ

    2016-02-01

    Full Text Available The thermophysical parameters of selected cheeses (processed cheese and half hard cheese are presented in the article. Cheese is a generic term for a diverse group of milk-based food products. Cheese is produced throughout the world in wide-ranging flavors, textures, and forms. Cheese goes during processing through the thermal and mechanical manipulation, so thermal properties are one of the most important. Knowledge about thermal parameters of cheeses could be used in the process of quality evaluation. Based on the presented facts thermal properties of selected cheeses which are produced by Slovak producers were measured. Theoretical part of article contains description of cheese and description of plane source method which was used for thermal parameters detection. Thermophysical parameters as thermal conductivity, thermal diffusivity and volume specific heat were measured during the temperature stabilisation. The results are presented as relations of thermophysical parameters to the temperature in temperature range from 13.5°C to 24°C. Every point of graphic relation was obtained as arithmetic average from measured values for the same temperature. Obtained results were statistically processed. Presented graphical relations were chosen according to the results of statistical evaluation and also according to the coefficients of determination for every relation. The results of thermal parameters are in good agreement with values measured by other authors for similar types of cheeses.

  9. Thermal and physical properties of bakery products.

    Science.gov (United States)

    Baik, O D; Marcotte, M; Sablani, S S; Castaigne, F

    2001-07-01

    This article reviews the measurement techniques, prediction models, and data on thermo-physical properties of bakery products: specific heat, thermal conductivity, thermal diffusivity, and density. Over the last decade, investigation has focused more on thermo-physical properties of nonbread bakery products. Both commonly used and new measurement techniques for thermo-physical properties reported in the publication are presented with directions for their proper use. Data and prediction models are tabulated for the range of moisture content and temperature of the bakery products.

  10. Method and apparatus for implementing material thermal property measurement by flash thermal imaging

    Science.gov (United States)

    Sun, Jiangang

    2017-11-14

    A method and apparatus are provided for implementing measurement of material thermal properties including measurement of thermal effusivity of a coating and/or film or a bulk material of uniform property. The test apparatus includes an infrared camera, a data acquisition and processing computer coupled to the infrared camera for acquiring and processing thermal image data, a flash lamp providing an input of heat onto the surface of a two-layer sample with an enhanced optical filter covering the flash lamp attenuating an entire infrared wavelength range with a series of thermal images is taken of the surface of the two-layer sample.

  11. Thermal Properties of Asphalt Mixtures Modified with Conductive Fillers

    Directory of Open Access Journals (Sweden)

    Byong Chol Bai

    2015-01-01

    Full Text Available This paper investigates the thermal properties of asphalt mixtures modified with conductive fillers used for snow melting and solar harvesting pavements. Two different mixing processes were adopted to mold asphalt mixtures, dry- and wet-mixing, and two conductive fillers were used in this study, graphite and carbon black. The thermal conductivity was compared to investigate the effects of asphalt mixture preparing methods, the quantity, and the distribution of conductive filler on thermal properties. The combination of conductive filler with carbon fiber in asphalt mixture was evaluated. Also, rheological properties of modified asphalt binders with conductive fillers were measured using dynamic shear rheometer and bending beam rheometer at grade-specific temperatures. Based on rheological testing, the conductive fillers improve rutting resistance and decrease thermal cracking resistance. Thermal testing indicated that graphite and carbon black improve the thermal properties of asphalt mixes and the combined conductive fillers are more effective than the single filler.

  12. Hygrothermal Properties and Performance of Sea Grass Insulation

    DEFF Research Database (Denmark)

    Eriksen, Marlene Stenberg Hagen; Laursen, Theresa Back; Rode, Carsten

    2008-01-01

    In the attempt to obtain knowledge of the hygrothermal properties of sea grass as thermal insulation, experiments have been carried out in the laboratory to determine the thermal conductivity, sorption properties and the water vapour permeability of the material. In order to investigate the hygro......In the attempt to obtain knowledge of the hygrothermal properties of sea grass as thermal insulation, experiments have been carried out in the laboratory to determine the thermal conductivity, sorption properties and the water vapour permeability of the material. In order to investigate...

  13. Measurement of thermal properties of magnetic nanoparticles using infrared thermal microscopy

    DEFF Research Database (Denmark)

    Kim, Jae Young; Chang, Ki Soo; Kook, Myung Ho

    2013-01-01

    Magnetic nanoparticles (MNPs) are considered promising for biomedical applications such as hyperthermia treatment and disease diagnosis owing to their distinctive thermal properties. For these applications, it is essential to screen the temperature distribution in the targeted disease site....... This study aimed to investigate and observe the thermal properties of a small amount of MNPs used as highly sensitive biomarkers for disease diagnosis by microthermography. Toward this end, we used polyacrylamide and agarose phantoms containing a small amount of MNPs (30 mg Fe-1). In phantoms, the increasing...

  14. Eutectic mixtures of some fatty acids for latent heat storage: Thermal properties and thermal reliability with respect to thermal cycling

    International Nuclear Information System (INIS)

    Sari, Ahmet

    2006-01-01

    Accelerated thermal cycle tests have been conducted to study the change in melting temperatures and latent heats of fusion of the eutectic mixtures of lauric acid (LA)-myristic acid (MA), lauric acid (LA)-palmitic acid (PA) and myristic acid (MA)-stearic acid (SA) as latent heat storage materials. The thermal properties of these materials were determined by the differential scanning calorimetry (DSC) analysis method. The thermal reliability of the eutectic mixtures after melt/freeze cycles of 720, 1080 and 1460 was also evaluated using the DSC curves. The accelerated thermal cycle tests indicate that the melting temperatures usually tend to decrease, and the variations in the latent heats of fusion are irregular with increasing number of thermal cycles. Moreover, the probable reasons for the change in thermal properties of the eutectic mixtures after repeated thermal cycles were investigated. Fourier Transform Infrared (FT-IR) spectroscopic analysis indicates that the accelerated melt/freeze processes do not cause any degradation in the chemical structure of the mixtures. The change in thermal properties of the eutectic mixtures with increasing number of thermal cycles is only because of the presence of certain amounts of impurities in the fatty acids used in their preparation. It is concluded that the tested eutectic mixtures have reasonable thermal properties and thermal reliability as phase change materials (PCMs) for latent heat storage in any solar heating applications that include a four year utilization period

  15. PHB/bentonite compounds: Effect of clay modification and thermal aging on properties

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Tatiara G.; Costa, Anna Raffaela M.; Canedo, Eduardo L.; Carvalho, Laura H. [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Wellen, Renate M.R., E-mail: tatiaraalmeida@gmail.com [Universidade Federal da Paraíba (UFPB), João Pessoa, PB (Brazil)

    2017-11-15

    Poly(3-hydroxybutyrate) (PHB) was compounded with three different Bentonite clays: natural, purified by ultrasound/sonicated and organically modified with hexadecyltrimethylammonium bromide. PHB/Bentonite masterbatches with 30% clay were prepared in a laboratory internal mixer and letdown with pure matrix to 1% and 3% w/w clay. Test samples were injection molded and characterized by x-ray diffraction (XRD), differential scanning calorimetry (DSC), infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Increase in Bentonite hydrophobic character was evinced by FTIR for organoclays. XRD of composites showed increase in clay interlayer distance and peak broadening, suggesting formation of intercalated nanocomposites. DSC showed increase in crystallinity and crystallization rate for compounds, especially for PHB/organoclay formulations. Thermal aging was conducted by exposing specimens at 115 deg C for up to 120 hours, and mechanical properties were measured according to ASTM standards. Elastic modulus increased and impact strength decreased with time and clay content; clay purification had little effect on the tensile properties. Tensile strength of thermal aged samples showed little variation, except for the organoclay nanocomposites, for which it significantly decreased with exposure time. SEM images displayed a whitened honeycomb structure and detachment of PHB/Bentonite layers which may be connected to cold crystallization and degradation processes taking place during thermal aging. (author)

  16. PHB/bentonite compounds: Effect of clay modification and thermal aging on properties

    International Nuclear Information System (INIS)

    Almeida, Tatiara G.; Costa, Anna Raffaela M.; Canedo, Eduardo L.; Carvalho, Laura H.; Wellen, Renate M.R.

    2017-01-01

    Poly(3-hydroxybutyrate) (PHB) was compounded with three different Bentonite clays: natural, purified by ultrasound/sonicated and organically modified with hexadecyltrimethylammonium bromide. PHB/Bentonite masterbatches with 30% clay were prepared in a laboratory internal mixer and letdown with pure matrix to 1% and 3% w/w clay. Test samples were injection molded and characterized by x-ray diffraction (XRD), differential scanning calorimetry (DSC), infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Increase in Bentonite hydrophobic character was evinced by FTIR for organoclays. XRD of composites showed increase in clay interlayer distance and peak broadening, suggesting formation of intercalated nanocomposites. DSC showed increase in crystallinity and crystallization rate for compounds, especially for PHB/organoclay formulations. Thermal aging was conducted by exposing specimens at 115 deg C for up to 120 hours, and mechanical properties were measured according to ASTM standards. Elastic modulus increased and impact strength decreased with time and clay content; clay purification had little effect on the tensile properties. Tensile strength of thermal aged samples showed little variation, except for the organoclay nanocomposites, for which it significantly decreased with exposure time. SEM images displayed a whitened honeycomb structure and detachment of PHB/Bentonite layers which may be connected to cold crystallization and degradation processes taking place during thermal aging. (author)

  17. Introduction of Differential Scanning Calorimetry in a General Chemistry Laboratory Course: Determination of Thermal Properties of Organic Hydrocarbons

    Science.gov (United States)

    D'Amelia, Ronald; Franks, Thomas; Nirode, William F.

    2007-01-01

    In first-year general chemistry undergraduate courses, thermodynamics and thermal properties such as melting points and changes in enthalpy ([Delta]H) and entropy ([Delta]S) of phase changes are frequently discussed. Typically, classical calorimetric methods of analysis are used to determine [Delta]H of reactions. Differential scanning calorimetry…

  18. Thermal and superthermal properties of supersymmetric field theories

    International Nuclear Information System (INIS)

    Fuchs, J.

    1984-01-01

    We discuss the finite-temperature behaviour of supersymmetric field theories. We show that their 'superthermal' properties which concern the question of susy breaking at finite temperature and their thermal properties must be considered separately. Susy breaking is determined by the so-called superthermal ensemble, whereas thermodynamical properties follow from the conventional thermal ensemble, leading to the usual statistics for the bosonic and fermionic components of a superfield. We show that superspace techniques can be used in a straightforward way only for superthermal Green functions but not for thermal ones. We also discuss the possibility of finite-temperature susy restoration and the implications of Goldstone's theorem at finite temperature. (orig.)

  19. Some Physco-thermal properties of Rice Bran | Obetta | Global ...

    African Journals Online (AJOL)

    Some of these properties were combined for study on their effect on thermal conductivity which was one of the thermal properties studied. Mean values of the thermal conductivity determined ranged from 0.2456 to 0.5764 W/m oC depending on the moisture content of the raw rice bran and the variety. The two major varieties ...

  20. Thermal properties of graphite oxide, thermally reduced graphene and chemically reduced graphene

    Science.gov (United States)

    Jankovský, Ondřej; Sedmidubský, David; Lojka, Michal; Sofer, Zdeněk

    2017-07-01

    We compared thermal behavior and other properties of graphite oxide, thermally reduced graphene and chemically reduced graphene. Graphite was oxidized according to the Hofmann method using potassium chlorate as oxidizing agent in strongly acidic environment. In the next step, the formed graphite oxide was chemically or thermally reduced yielding graphene. The mechanism of thermal reduction was studied using STA-MS. Graphite oxide and both thermally and chemically reduced graphenes were analysed by SEM, EDS, elemental combustion analysis, XPS, Raman spectroscopy, XRD and BET. These findings will help for the large scale production of graphene with appropriate chemical composition.

  1. Preparation, characterization, and thermal properties of microencapsulated phase change material for thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Alkan, Cemil; Sari, Ahmet; Karaipekli, Ali [Department of Chemistry, Gaziosmanpasa University, 60240 Tokat (Turkey); Uzun, Orhan [Department of Physics, Gaziosmanpasa University, 60240 Tokat (Turkey)

    2009-01-15

    This study is focused on the preparation, characterization, and determination of thermal properties of microencapsulated docosane with polymethylmethacrylate (PMMA) as phase change material for thermal energy storage. Microencapsulation of docosane has been carried out by emulsion polymerization. The microencapsulated phase change material (MEPCM) was characterized using scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. Thermal properties and thermal stability of MEPCM were measured by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). DSC analysis indicated that the docosane in the microcapsules melts at 41.0 C and crystallizes at 40.6 C. It has latent heats of 54.6 and -48.7 J/g for melting and crystallization, respectively. TGA showed that the MEPCM degraded in three distinguishable steps and had good chemical stability. Accelerated thermal cycling tests also indicated that the MEPCM had good thermal reliability. Based on all these results, it can be concluded that the microencapsulated docosane as MEPCMs have good potential for thermal energy storage purposes such as solar space heating applications. (author)

  2. The thermal and mechanical properties of electron beam-irradiated polylactide

    International Nuclear Information System (INIS)

    Kuk, In Seol; Jung, Chan Hee; Hwang, In Tae; Choi, Jae Hak; Nho, Young Chang

    2010-01-01

    The effect of electron beam irradiation on the thermal and mechanical properties of polylactide (PLA) was investigated in this research. PLA films were irradiated by electron beams at different absorption doses ranging from 20 to 200 kGy. The thermal and mechanical properties of the irradiated PLA films were investigated by means of differential scanning calorimeter, thermogravimetric analyzer, universal testing machine, dynamic mechanical analyzer, and thermal mechanical analyzer. The results revealed that the chain scission of the PLA predominated over the crosslinking during the irradiation, which considerably deteriorated the thermal and mechanical properties of the PLA

  3. Calculation of experiment uncertainty in laboratory determination of several geoengineering properties of tuffs from Yucca Mountain, Nevada; Yucca Mountain Site Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    Nimick, F.B.; Schwartz, B.M.; Price, R.H.

    1991-11-01

    A method for estimating the precision and accuracy of measured parameters is described. Examples of application of the estimating method are presented for density, porosity, compressive strength, Young`s modulus, Poisson`s ratio, and thermal expansion. With the exception of the coefficient of linear thermal expansion, all laboratory data for these properties for tuff samples appear to have reasonable experiment uncertainties. Uncertainties in the thermal-expansion coefficients may be as high as 39% of the values, although most uncertainties for the coefficients are probably {le}2%. 4 refs., 1 fig., 15 tabs.

  4. General Properties for an Agrawal Thermal Engine

    Science.gov (United States)

    Paéz-Hernández, Ricardo T.; Chimal-Eguía, Juan Carlos; Sánchez-Salas, Norma; Ladino-Luna, Delfino

    2018-04-01

    This paper presents a general property of endoreversible thermal engines known as the Semisum property previously studied in a finite-time thermodynamics context for a Curzon-Ahlborn (CA) engine but now extended to a simplified version of the CA engine studied by Agrawal in 2009 (A simplified version of the Curzon-Ahlborn engine, European Journal of Physics 30 (2009), 1173). By building the Ecological function, proposed by Angulo-Brown (An ecological optimization criterion for finite-time heat engines, Journal of Applied Physics 69 (1991), 7465-7469) in 1991, and considering two heat transfer laws an analytical expression is obtained for efficiency and power output which depends only on the heat reservoirs' temperature. When comparing the existing efficiency values of real power plants and the theoretical efficiencies obtained in this work, it is observed that the Semisum property is satisfied. Moreover, for the Newton and the Dulong-Petit heat transfer laws the existence of the g function is demonstrated and we confirm that in a Carnot-type thermal engine there is a general property independent of the heat transfer law used between the thermal reservoirs and the working substance.

  5. Thermal Properties of Polymethyl Methacrylate Composite Containing Copper Nanoparticles.

    Science.gov (United States)

    Yu, Wei; Xie, Huaqing; Xin, Sha; Yin, Junshan; Jiang, Yitong; Wang, Mingzhu

    2015-04-01

    Thermal functional Materials have wide applications in thermal management fields, and inserting highly thermal conductive materials is effective in enhancing thermal conductivity of matrix. In this paper, copper nanoparticles were selected as the additive to prepare polymethyl methacrylate (PMMA) based nanocomposite with enhanced thermal properties. Uniform copper nanoparticles with pure face-centered lattice were prepared by liquid phase reduction method. Then, they were added into PMMA/N, N-Dimethylmethanamide (DMF) solution according to the different mass fraction for uniform dispersion. After DMF was evaporated, Cu-PMMA nanocomposites were gained. The thermal analysis measurement results showed that the decomposition temperature of nanocomposites decreased gradually with the increasing particle loadings. The thermal conductivity of the Cu-PMMA nanocomposites rose with the increasing contents of copper nanoparticles. With a 20 vol.% addition, the thermal conductivity was up to 1.2 W/m · K, a 380.5% increase compared to the pure PMMA. The results demonstrate that copper nanoparticles have great potential in enhancing thermal transport properties of polymer.

  6. Investigation on seasonal variation of thermal-induced strain in flexible pavements based on field and laboratory measurements

    Directory of Open Access Journals (Sweden)

    Simita Biswas

    2016-09-01

    Full Text Available Pavement temperature variation has a large influence on the structural response of flexible pavements. Daily and seasonal temperature fluctuation causes expansion and contraction of pavement material, which then leads to the generation of thermal strain. In this study, field observation and laboratory tests were conducted to investigate seasonal variation of thermal-induced strain in flexible pavement. Field observations were conducted at the Integrated Road Research Facility (IRRF’s test road in Edmonton, Alberta, Canada, which is fully equipped with structural and environmental monitoring instruments. The main objective of the field study was to compare the variation of thermal-induced strain in warm and cold seasons. Field results indicated that thermal-induced strain is 1.4–2.0 times greater in cold seasons than in warm seasons following the same pavement temperature variations; however, strain generation rate was greater in warm seasons. Laboratory testing of asphalt slab and cylindrical samples produced comparable ratios. Moreover, field observation and laboratory testing showed a similar trend of temperature and thermal strain variations. Keywords: Thermal-induced strain, Asphalt strain gauge, Field observation, Flexible pavement, Laboratory testing, Seasonal variation

  7. Thermal properties and thermal reliability of eutectic mixtures of some fatty acids as latent heat storage materials

    International Nuclear Information System (INIS)

    Sari, Ahmet; Sari, Hayati; Oenal, Adem

    2004-01-01

    The present study deals with two subjects. The first one is to determine the thermal properties of lauric acid (LA)-stearic acid (SA), myristic acid (MA)-palmitic acid (PA) and palmitic acid (PA)-stearic acid (SA) eutectic mixtures as latent heat storage material. The properties were measured by the differential scanning calorimetry (DSC) analysis technique. The second one is to study the thermal reliability of these materials in view of the change in their melting temperatures and latent heats of fusion with respect to repeated thermal cycles. For this aim, the eutectic mixtures were subjected to 360 repeated melt/freeze cycles, and their thermal properties were measured after 0, 90,180 and 360 thermal cycles by the technique of DSC analysis. The DSC thermal analysis results show that the binary systems of LA-SA in the ratio of 75.5:24.5 wt.%, MA-PA in the ratio of 58:42 wt.% and PA-SA in the ratio of 64.2:35.8 wt.% form eutectic mixtures with melting temperatures of 37.0, 42.60 and 52.30 deg. C and with latent heats of fusion of 182.7, 169.7 and 181.7 J g -1 , respectively. These thermal properties make them possible for heat storage in passive solar heating applications with respect to climate conditions. The accelerated thermal cycle tests indicate that the changes in the melting temperatures and latent heats of fusion of the studied eutectic mixtures are not regular with increasing number of thermal cycles. However, these materials, latent heat energy storage materials, have good thermal reliability in terms of the change in their thermal properties with respect to thermal cycling for about a one year utility period

  8. Thermal Properties for the Thermal-Hydraulics Analyses of the BR2 Maximum Nominal Heat Flux

    Energy Technology Data Exchange (ETDEWEB)

    Dionne, B. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Bergeron, A. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Licht, J. R. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Kim, Y. S. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Hofman, G. L. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

    2015-02-01

    This memo describes the assumptions and references used in determining the thermal properties for the various materials used in the BR2 HEU (93% enriched in 235U) to LEU (19.75% enriched in 235U) conversion feasibility analysis. More specifically, this memo focuses on the materials contained within the pressure vessel (PV), i.e., the materials that are most relevant to the study of impact of the change of fuel from HEU to LEU. Section 2 provides a summary of the thermal properties in the form of tables while the following sections and appendices present the justification of these values. Section 3 presents a brief background on the approach used to evaluate the thermal properties of the dispersion fuel meat and specific heat capacity. Sections 4 to 7 discuss the material properties for the following materials: i) aluminum, ii) dispersion fuel meat (UAlx-Al and U-7Mo-Al), iii) beryllium, and iv) stainless steel. Section 8 discusses the impact of irradiation on material properties. Section 9 summarizes the material properties for typical operating temperatures. Appendix A elaborates on how to calculate dispersed phase’s volume fraction. Appendix B provides a revised methodology for determining the thermal conductivity as a function of burnup for HEU and LEU.

  9. Simultaneous reconstruction of thermal degradation properties for anisotropic scattering fibrous insulation after high temperature thermal exposures

    International Nuclear Information System (INIS)

    Zhao, Shuyuan; Zhang, Wenjiao; He, Xiaodong; Li, Jianjun; Yao, Yongtao; Lin, Xiu

    2015-01-01

    To probe thermal degradation behavior of fibrous insulation for long-term service, an inverse analysis model was developed to simultaneously reconstruct thermal degradation properties of fibers after thermal exposures from the experimental thermal response data, by using the measured infrared spectral transmittance and X-ray phase analysis data as direct inputs. To take into account the possible influence of fibers degradation after thermal exposure on the conduction heat transfer, we introduced a new parameter in the thermal conductivity model. The effect of microstructures on the thermal degradation parameters was evaluated. It was found that after high temperature thermal exposure the decay rate of the radiation intensity passing through the material was weakened, and the probability of being scattered decreased during the photons traveling in the medium. The fibrous medium scattered more radiation into the forward directions. The shortened heat transfer path due to possible mechanical degradation, along with the enhancement of mean free path of phonon scattering as devitrification after severe heat treatment, made the coupled solid/gas thermal conductivities increase with the rise of heat treatment temperature. - Highlights: • A new model is developed to probe conductive and radiative properties degradation of fibers. • To characterize mechanical degradation, a new parameter is introduced in the model. • Thermal degradation properties are reconstructed from experiments by L–M algorithm. • The effect of microstructures on the thermal degradation parameters is evaluated. • The analysis provides a powerful tool to quantify thermal degradation of fiber medium

  10. Enhancement in thermal and mechanical properties of bricks

    Directory of Open Access Journals (Sweden)

    Shibib Khalid S.

    2013-01-01

    Full Text Available A new type of porous brick is proposed. Sawdust is initially well mixed with wet clay in order to create voids inside the brick during the firing process. The voids will enhance the total performance of the brick due to the reduction of its density and thermal conductivity and a minor reduction of its compressive stress. All these properties have been measured experimentally and good performance has been obtained. Although a minor reduction in compressive stress has been observed with increased porosity, this property has still been larger than that of the common used hollow brick. Data obtained by this work lead to a new type of effective brick having a good performance with no possibility that mortar enters inside the holes which is the case with the common used hollow bricks. The mortar has a determent effect on thermal properties of the wall since it has some higher thermal conductivity and density than that of brick which increases the wall overall density and thermal conductivity of the wall.

  11. Low thermal dependence of the contractile properties of a wing muscle in the bat Carollia perspicillata.

    Science.gov (United States)

    Rummel, Andrea D; Swartz, Sharon M; Marsh, Richard L

    2018-05-29

    Temperature affects contractile rate properties in muscle, which may affect locomotor performance. Endotherms are known to maintain high core body temperatures, but temperatures in the periphery of the body can fluctuate. Such a phenomenon occurs in bats, whose wing musculature is relatively poorly insulated, resulting in substantially depressed temperatures in the distal wing. We examined a wing muscle in the small-bodied tropical bat Carollia perspicillata and a hindlimb muscle in the laboratory mouse at 5°C intervals from 22 to 42°C to determine the thermal dependence of the contractile properties of both muscles. We found that the bat ECRL had low thermal dependence from near body temperature to 10°C lower, with Q 10 values of less than 1.5 for relaxation from contraction and shortening velocities in that interval, and with no significant difference in some rate properties in the interval between 32 and 37°C. In contrast, for all temperature intervals below 37°C, Q 10 values for the mouse EDL were 1.5 or higher, and rate properties differed significantly across successive temperature intervals from 37 to 22°C. An ANCOVA analysis found that the thermal dependencies of all measured isometric and isotonic rate processes were significantly different between the bat and mouse muscles. The relatively low thermal dependence of the bat muscle likely represents a downward shift of its optimal temperature and may be functionally significant in light of the variable operating temperatures of bat wing muscles. © 2018. Published by The Company of Biologists Ltd.

  12. BOW SHOCK FRAGMENTATION DRIVEN BY A THERMAL INSTABILITY IN LABORATORY ASTROPHYSICS EXPERIMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki-Vidal, F.; Lebedev, S. V.; Pickworth, L. A.; Swadling, G. F.; Skidmore, J.; Hall, G. N.; Bennett, M.; Bland, S. N.; Burdiak, G.; De Grouchy, P.; Music, J.; Suttle, L. [Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom); Ciardi, A. [Sorbonne Universités, UPMC Univ. Paris 6, UMR 8112, LERMA, F-75005, Paris (France); Rodriguez, R.; Gil, J. M.; Espinosa, G. [Departamento de Fisica de la Universidad de Las Palmas de Gran Canaria, E-35017 Las Palmas de Gran Canaria (Spain); Hartigan, P. [Department of Physics and Astronomy, Rice University, 6100 S. Main, Houston, TX 77521-1892 (United States); Hansen, E.; Frank, A., E-mail: f.suzuki@imperial.ac.uk [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States)

    2015-12-20

    The role of radiative cooling during the evolution of a bow shock was studied in laboratory-astrophysics experiments that are scalable to bow shocks present in jets from young stellar objects. The laboratory bow shock is formed during the collision of two counterstreaming, supersonic plasma jets produced by an opposing pair of radial foil Z-pinches driven by the current pulse from the MAGPIE pulsed-power generator. The jets have different flow velocities in the laboratory frame, and the experiments are driven over many times the characteristic cooling timescale. The initially smooth bow shock rapidly develops small-scale nonuniformities over temporal and spatial scales that are consistent with a thermal instability triggered by strong radiative cooling in the shock. The growth of these perturbations eventually results in a global fragmentation of the bow shock front. The formation of a thermal instability is supported by analysis of the plasma cooling function calculated for the experimental conditions with the radiative packages ABAKO/RAPCAL.

  13. Thermal properties of light-weight concrete with waste polypropylene aggregate

    Science.gov (United States)

    Záleská, Martina; Pokorný, Jaroslav; Pavlíková, Milena; Pavlík, Zbyšek

    2017-07-01

    Thermal properties of a sustainable light-weight concrete incorporating high volume of waste polypropylene as partial substitution of natural aggregate were studied in the paper. Glass fiber reinforced polypropylene (GFPP), a by-product of PP tubes production, partially substituted fine natural silica aggregate in 10, 20, 30, 40, and 50 mass%. In order to quantify the effect of GFPP use on concrete properties, a reference concrete mix without plastic waste was studied as well. For the applied GFPP, bulk density, matrix density, and particle size distribution were measured. Specific attention was paid to thermal transport and storage properties of GFPP that were examined in dependence on compaction time. For the developed light-weight concrete, thermal properties were accessed using transient impulse technique, whereas the measurement was done in dependence on moisture content, from the dry state to fully water saturated state. Additionally, the investigated thermal properties were plotted as function of porosity. The tested light-weight concrete was found to be prospective construction material possessing improved thermal insulation function. Moreover, the reuse of waste plastics in concrete composition was beneficial both from the environmental and financial point of view considering plastics low biodegradability and safe disposal.

  14. Using of Aerogel to Improve Thermal Insulating Properties of Windows

    Science.gov (United States)

    Valachova, Denisa; Zdrazilova, Nada; Panovec, Vladan; Skotnicova, Iveta

    2018-06-01

    For the best possible thermal-technical properties of building structures it is necessary to use materials with very low thermal conductivity. Due to the increasing thermal-technical requirements for building structures, the insulating materials are developed. One of the modern thermal insulating materials is so-called aerogel. Unfortunately, this material is not used in the field of external thermal insulation composite systems because of its price and its properties. The aim of this paper is to present possibilities of using this insulating material in the civil engineering - specifically a usage of aerogel in the production of windows.

  15. On thermal properties of hard rocks as a host environment of an underground thermal energy storage

    Science.gov (United States)

    Novakova, L.; Hladky, R.; Broz, M.; Novak, P.; Lachman, V.; Sosna, K.; Zaruba, J.; Metelkova, Z.; Najser, J.

    2013-12-01

    With increasing focus on environmentally friendly technologies waste heat recycling became an important issue. Under certain circumstances subsurface environment could be utilized to accommodate relatively large quantity of heat. Industrial waste heat produced during warm months can be stored in an underground thermal energy storage (UTES) and used when needed. It is however a complex task to set up a sustainable UTES for industrial scale. Number of parameters has to be studied and evaluated by means of thermohydromechanical and chemical coupling (THMC) before any UTES construction. Thermal characteristics of various rocks and its stability under thermal loading are amongst the most essential. In the Czech Republic study two complementary projects THMC processes during an UTES operation. The RESEN project (www.resen.cz) employs laboratory tests and experiments to characterise thermal properties of hard rocks in the Bohemian Massif. Aim of the project is to point out the most suitable rock environment in the Bohemian Massif for moderate to ultra-high temperature UTES construction (Sanyal, 2005). The VITA project (www.geology.cz/mokrsko) studies THM coupling in non-electrical temperature UTES using long term in-situ experiment. In both projects thermal properties of rocks were studied. Thermal conductivity and capacity were measured on rock samples. In addition an influence of increasing temperature and moisture content was considered. Ten hard rocks were investigated. The set included two sandstones, two ignibrites, a melaphyr, a syenite, two granites, a gneiss and a serpentinite. For each rock there were measured thermal conductivity and capacity of at least 54 dried samples. Subsequently, the samples were heated up to 380°C in 8 hours and left to cool down. Thermal characteristics were measured during the heating period and after the sample reached room temperature. Heating and cooling cycle was repeated 7 to 10 times to evaluate possible UTES-like degradation of

  16. Thermal properties of alkali-activated aluminosilicates with CNT admixture

    Science.gov (United States)

    Zmeskal, Oldrich; Trhlikova, Lucie; Fiala, Lukas; Florian, Pavel; Cerny, Robert

    2017-07-01

    Material properties of electrically conductive cement-based materials with increased attention paid on electric and thermal properties were often studied in the last years. Both electric and thermal properties play an important role thanks to their possible utilization in various practical applications (e.g. snow-melting systems or building structures monitoring systems without the need of an external monitoring system). The DC/AC characteristics depend significantly on the electrical resistivity and the electrical capacity of bulk materials. With respect to the DC/AC characteristics of cement-based materials, such materials can be basically classified as electric insulators. In order to enhance them, various conductive admixtures such as those based on different forms of carbon, can be used. Typical representatives of carbon-based admixtures are carbon nanotubes (CNT), carbon fibers (CF), graphite powder (GP) and carbon black (CB). With an adequate amount of such admixtures, electric properties significantly change and new materials with higher added value can be prepared. However, other types of materials can be enhanced in the same way. Alkali-activated aluminosilicates (AAA) based on blast furnace slag are materials with high compressive strength comparable with cement-based materials. Moreover, the price of slag is lower than of Portland cement. Therefore, this paper deals with the study of thermal properties of this promising material with different concentrations of CNT. Within the paper a simple method of basic thermal parameters determination based on the thermal transient response to a heat power step is presented.

  17. Non-destructive thermal wave method applied to study thermal properties of fast setting time endodontic cement

    Science.gov (United States)

    Picolloto, A. M.; Mariucci, V. V. G.; Szpak, W.; Medina, A. N.; Baesso, M. L.; Astrath, N. G. C.; Astrath, F. B. G.; Santos, A. D.; Moraes, J. C. S.; Bento, A. C.

    2013-11-01

    The thermal wave method is applied for thermal properties measurement in fast endodontic cement (CER). This new formula is developed upon using Portland cement in gel and it was successfully tested in mice with good biocompatibility and stimulated mineralization. Recently, thermal expansion and setting time were measured, conferring to this material twice faster hardening than the well known Angelus Mineral trioxide aggregate (MTA) the feature of fast hardening (˜7 min) and with similar thermal expansion (˜12 μstrain/ °C). Therefore, it is important the knowledge of thermal properties like thermal diffusivity, conductivity, effusivity in order to match thermally the tissue environment upon its application in filling cavities of teeth. Photothermal radiometry technique based on Xe illumination was applied in CER disks 600 μm thick for heating, with prepared in four particle sizes (25, 38, 45, and 53) μm, which were added microemulsion gel with variation volumes (140, 150, 160, and 170) μl. The behavior of the thermal diffusivity CER disks shows linear decay for increase emulsion volume, and in contrast, thermal diffusivity increases with particles sizes. Aiming to compare to MTA, thermal properties of CER were averaged to get the figure of merit for thermal diffusivity as (44.2 ± 3.6) × 10-3 cm2/s, for thermal conductivity (228 ± 32) mW/cm K, the thermal effusivity (1.09 ± 0.06) W s0.5/cm2 K and volume heat capacity (5.2 ± 0.7) J/cm3 K, which are in excellent agreement with results of a disk prepared from commercial MTA-Angelus (grain size < 10 μm using 57 μl of distilled water).

  18. Preliminary laboratory investigation of thermally treated recycled concrete aggregate for general use in concrete

    NARCIS (Netherlands)

    Larbi, J.A.; Heijnen, W.M.M.; Brouwer, J.P.; Mulder, E.

    2000-01-01

    This paper deals with a preliminary laboratory study to assess the effectiveness of thermal treatment methods to improve the quality of recycled concrete aggregate. The samples used for the study consisted of sieved fractions of crushed concrete that were subjected to various thermal treatments at

  19. Thermal radiation properties of PTFE plasma

    Science.gov (United States)

    Liu, Xiangyang; Wang, Siyu; Zhou, Yang; Wu, Zhiwen; Xie, Kan; Wang, Ningfei

    2017-06-01

    To illuminate the thermal transfer mechanism of devices adopting polytetrafluoroethylene (PTFE) as ablation materials, the thermal radiation properties of PTFE plasma are calculated and discussed based on local thermodynamic equilibrium (LTE) and optical thin assumptions. It is clarified that line radiation is the dominant mechanism of PTFE plasma. The emission coefficient shows an opposite trend for both wavelength regions divided by 550 nm at a temperature above 15 000 K. The emission coefficient increases with increasing temperature and pressure. Furthermore, it has a good log linear relation with pressure. Equivalent emissivity varies complexly with temperature, and has a critical point between 20 000 K to 25 000 K. The equivalent cross points of the average ionic valence and radiation property are about 10 000 K and 15 000 K for fully single ionization.

  20. Effect of thermal modification on the physical properties of juvenile and mature woods of Eucalyptus grandis

    Directory of Open Access Journals (Sweden)

    Fred Willians Calonego

    Full Text Available This study aimed to evaluate the effect of thermal treatment on the physical properties of juvenile and mature woods of Eucalyptus grandis. Boards were taken from 30-year-old E. grandis trees. The boards were thermally modified at 180 °C in the Laboratory of Wood Drying and Preservation at UNESP, Botucatu, Sao Paulo state, Brazil. The results showed that thermal modification caused: (1 decrease of 6.8% in the density at 0% equilibrium moisture content of mature wood; (2 significant decreases of 14.7% and 35.6% in the maximum volumetric swellings of juvenile and mature woods, respectively; (3 significant decreases of 13.7% and 21.3% in the equilibrium moisture content of juvenile and mature woods, respectively. The influence of thermal modification in juvenile wood was lower than in mature wood and caused greater uniformity in the physical variations between these types of wood in E. grandis.

  1. Thermal properties of graphene under tensile stress

    Science.gov (United States)

    Herrero, Carlos P.; Ramírez, Rafael

    2018-05-01

    Thermal properties of graphene display peculiar characteristics associated to the two-dimensional nature of this crystalline membrane. These properties can be changed and tuned in the presence of applied stresses, both tensile and compressive. Here, we study graphene monolayers under tensile stress by using path-integral molecular dynamics (PIMD) simulations, which allows one to take into account quantization of vibrational modes and analyze the effect of anharmonicity on physical observables. The influence of the elastic energy due to strain in the crystalline membrane is studied for increasing tensile stress and for rising temperature (thermal expansion). We analyze the internal energy, enthalpy, and specific heat of graphene, and compare the results obtained from PIMD simulations with those given by a harmonic approximation for the vibrational modes. This approximation turns out to be precise at low temperatures, and deteriorates as temperature and pressure are increased. At low temperature, the specific heat changes as cp˜T for stress-free graphene, and evolves to a dependence cp˜T2 as the tensile stress is increased. Structural and thermodynamic properties display non-negligible quantum effects, even at temperatures higher than 300 K. Moreover, differences in the behavior of the in-plane and real areas of graphene are discussed, along with their associated properties. These differences show up clearly in the corresponding compressibility and thermal expansion coefficient.

  2. Thermal properties of cesium molybdate

    International Nuclear Information System (INIS)

    Minato, Kazuo; Fukuda, Kousaku; Takano, Masahide; Sato, Seichi; Ohashi, Hiroshi

    1996-01-01

    Cesium is one of the most important fission products to aid in the understanding and prediction of the behavior of oxide nuclear fuels because of its high mobility, chemical reactivity, and large yield. In postirradiation examinations of the Phoenix reactor fuel pins, the accumulation of cesium and molybdenum between the fuel pellet and cladding was observed, though the chemical form was not determined. In the thermodynamic analyses of chemical states of fission products, Cs 2 MoO 4 was often predicted to exist as a stable compound in oxide fuels. The Cs 2 MoO 4 compound is thermodynamically stable under the conditions of light water reactors, fast breeder reactors, and high-temperature gas-cooled reactors. In the Cs-Mo-O system several phases have been found, and the structural and thermodynamic properties were studied. At room temperature, Cs 2 MoO 4 has an orthorhombic structure and a phase transition occurs at 841 K to a hexagonal structure. Both structures are expected to exist in the fuel, depending on the fuel temperature. However, no data has been available on the thermal properties of CS 2 MoO 4 . In the current work, the thermal expansion and thermal conductivity of Cs 2 MoO 4 were determined, which are the basic data needed to understand and predict the fuel/clad mechanical interaction and fuel temperature

  3. Thermal shock investigation of silicon nitride

    International Nuclear Information System (INIS)

    Ziegler, G.; Leucht, R.

    1977-01-01

    In this work, the thermal shock properties of commercial reaction-bonded Si 3 N 4 quality material (RBSN), of commercial hot-pressed Si 3 N 4 (HPSN) and of different laboratory grades of hot-pressed Si 3 N 4 were examined. The thermal shock properties of RBSN quality material differ according to the structure considerably: The critical temperature difference for sample crossections of 5 x 5 or 6 x 6 mm after quenching in oil lies between 730 0 C and over 1400 0 C. The best thermal shock properties are shown by high density RBSN quality material having very fine pores and high initial strength. The results indicate that for RBSN large pores and density inhomogenities are responsible for bad thermal shock properties. Resistance to fast temperature change is higher for hot-pressed Si 3 N 4 than for RBSN quality material. In HPSN, the thermal shock results show dependence on structure. High MgO content and the associated coarse rod-shaped configuration of the β phase and structural inhomogenities affect the thermal shock properties in an adverse way. (orig.) [de

  4. Acoustic and thermal properties of tissue

    Science.gov (United States)

    Retat, L.; Rivens, I.; ter Haar, G. R.

    2012-10-01

    Differences in ultrasound (US) and thermal properties of abdominal soft tissues may affect the delivery of thermal therapies such as high intensity focused ultrasound and may provide a basis for US monitoring of such therapies. 21 rat livers were obtained, within one hour of surgical removal. For a single liver, 3 lobes were selected and each treated in one of 3 ways: maintained at room temperature, water bath heated to 50°C ± 1°C for 10 ± 0.5 minutes, or water bath heated to 60°C ± 1°C for 10 ± 0.6 minutes. The attenuation coefficient, speed of sound and thermal conductivity of fresh rat liver was measured. The attenuation coefficients and speed of sound were measured using the finite-amplitude insertion-substitution (FAIS) method. For each rat liver, the control and treated lobes were scanned using a pair of weakly focused 2.5 MHz Imasonic transducers over the range 1.8 to 3 MHz. The conductivity measurement apparatus was designed to provide one-dimensional heat flow through each specimen using a combination of insulation, heat source and heat sink. Using 35 MHz US images to determine the volume of air trapped in the system, the thermal conductivity was corrected using a simulation based on the Helmhotz bio-heat equation. The process of correlating these results with biological properties is discussed.

  5. Experiment study on the thermal properties of paraffin/kaolin thermal energy storage form-stable phase change materials

    International Nuclear Information System (INIS)

    Lv, Peizhao; Liu, Chenzhen; Rao, Zhonghao

    2016-01-01

    Highlights: • Different particle sizes of kaolin were employed to load paraffin. • The effects and reasons of particle size on thermal conductivity were studied. • Thermal property and thermal stability of the composites were investigated. • The leakage and thermal storage and release rate of the composites were studied. • The effect of vacuum impregnation method on thermal conductivity was investigated. - Abstract: In this paper, different particle sizes of kaolin were employed to incorporate paraffin via vacuum impregnation method. The paraffin/kaolin composites were characterized by Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimeter (DSC) and Thermogravimetry (TG). The results showed that the paraffin/kaolin composite with the largest particle size of kaolin (K4) has the highest thermal conductivity (0.413 W/(m K) at 20 °C) among the diverse composites. The latent heat capacity of paraffin/K4 is 119.49 J/g and the phase change temperature is 62.4 °C. In addition, the thermal properties and thermal conductivities of paraffin/K4 with different mass fraction of K4 (0–60%) were investigated. The thermal conductivities of the composites were explained in microcosmic field. The phonon mean free path determines the thermal conductivity, and it can be significantly affected by temperature and the contact surface area. The leaks, thermal storage and release properties of pure paraffin and paraffin/kaolin composites were investigated and the composites presented good thermal stabilities.

  6. Laboratory electron exposure of TSS-1 thermal control coating

    Science.gov (United States)

    Vaughn, J. A.; Mccollum, M.; Carruth, M. R., Jr.

    1995-01-01

    RM400, a conductive thermal control coating, was developed for use on the exterior shell of the tethered satellite. Testing was performed by the Engineering Physics Division to quantify effects of the space environment on this coating and its conductive and optical properties. Included in this testing was exposure of RM400 to electrons with energies ranging from 0.1 to 1 keV, to simulate electrons accelerated from the ambient space plasma when the tethered satellite is fully deployed. During this testing, the coating was found to luminesce, and a prolonged exposure of the coating to high-energy electrons caused the coating to darken. This report describes the tests done to quantify the degradation of the thermal control properties caused by electron exposure and to measure the luminescence as a function of electron energy and current density to the satellite.

  7. Non-destructive thermal wave method applied to study thermal properties of fast setting time endodontic cement

    Energy Technology Data Exchange (ETDEWEB)

    Picolloto, A. M.; Mariucci, V. V. G.; Szpak, W.; Medina, A. N.; Baesso, M. L.; Astrath, N. G. C.; Astrath, F. B. G.; Bento, A. C., E-mail: acbento@uem.br [Departamento de Física, Grupo de Espectroscopia Fotoacústica e Fototérmica, Universidade Estadual de Maringá – UEM, Av. Colombo 5790, 87020-900 Maringá, Paraná (Brazil); Santos, A. D.; Moraes, J. C. S. [Departamento de Física e Química, Universidade Estadual Paulista Júlio de Mesquita Filho – UNESP, Av. Brasil 56, 15385-000 Ilha Solteira, SP (Brazil)

    2013-11-21

    The thermal wave method is applied for thermal properties measurement in fast endodontic cement (CER). This new formula is developed upon using Portland cement in gel and it was successfully tested in mice with good biocompatibility and stimulated mineralization. Recently, thermal expansion and setting time were measured, conferring to this material twice faster hardening than the well known Angelus Mineral trioxide aggregate (MTA) the feature of fast hardening (∼7 min) and with similar thermal expansion (∼12 μstrain/ °C). Therefore, it is important the knowledge of thermal properties like thermal diffusivity, conductivity, effusivity in order to match thermally the tissue environment upon its application in filling cavities of teeth. Photothermal radiometry technique based on Xe illumination was applied in CER disks 600 μm thick for heating, with prepared in four particle sizes (25, 38, 45, and 53) μm, which were added microemulsion gel with variation volumes (140, 150, 160, and 170) μl. The behavior of the thermal diffusivity CER disks shows linear decay for increase emulsion volume, and in contrast, thermal diffusivity increases with particles sizes. Aiming to compare to MTA, thermal properties of CER were averaged to get the figure of merit for thermal diffusivity as (44.2 ± 3.6) × 10{sup −3} cm{sup 2}/s, for thermal conductivity (228 ± 32) mW/cm K, the thermal effusivity (1.09 ± 0.06) W s{sup 0.5}/cm{sup 2} K and volume heat capacity (5.2 ± 0.7) J/cm{sup 3} K, which are in excellent agreement with results of a disk prepared from commercial MTA-Angelus (grain size < 10 μm using 57 μl of distilled water)

  8. Non-destructive thermal wave method applied to study thermal properties of fast setting time endodontic cement

    International Nuclear Information System (INIS)

    Picolloto, A. M.; Mariucci, V. V. G.; Szpak, W.; Medina, A. N.; Baesso, M. L.; Astrath, N. G. C.; Astrath, F. B. G.; Bento, A. C.; Santos, A. D.; Moraes, J. C. S.

    2013-01-01

    The thermal wave method is applied for thermal properties measurement in fast endodontic cement (CER). This new formula is developed upon using Portland cement in gel and it was successfully tested in mice with good biocompatibility and stimulated mineralization. Recently, thermal expansion and setting time were measured, conferring to this material twice faster hardening than the well known Angelus Mineral trioxide aggregate (MTA) the feature of fast hardening (∼7 min) and with similar thermal expansion (∼12 μstrain/ °C). Therefore, it is important the knowledge of thermal properties like thermal diffusivity, conductivity, effusivity in order to match thermally the tissue environment upon its application in filling cavities of teeth. Photothermal radiometry technique based on Xe illumination was applied in CER disks 600 μm thick for heating, with prepared in four particle sizes (25, 38, 45, and 53) μm, which were added microemulsion gel with variation volumes (140, 150, 160, and 170) μl. The behavior of the thermal diffusivity CER disks shows linear decay for increase emulsion volume, and in contrast, thermal diffusivity increases with particles sizes. Aiming to compare to MTA, thermal properties of CER were averaged to get the figure of merit for thermal diffusivity as (44.2 ± 3.6) × 10 −3 cm 2 /s, for thermal conductivity (228 ± 32) mW/cm K, the thermal effusivity (1.09 ± 0.06) W s 0.5 /cm 2 K and volume heat capacity (5.2 ± 0.7) J/cm 3 K, which are in excellent agreement with results of a disk prepared from commercial MTA-Angelus (grain size < 10 μm using 57 μl of distilled water)

  9. Thermal capacitator design rationale. Part 1: Thermal and mechanical property data for selected materials potentially useful in thermal capacitor design and construction

    Science.gov (United States)

    Bailey, J. A.; Liao, C. K.

    1975-01-01

    The thermal properties of paraffin hydrocarbons and hydrocarbon mixtures which may be used as the phase change material (PCM) in thermal capacitors are discussed. The paraffin hydrocarbons selected for consideration are those in the range from C11H24 (n-Undecane) to C20H42 (n-Eicosane). A limited amount of data is included concerning other properties of paraffin hydrocarbons and the thermal and mechanical properties of several aluminum alloys which may find application as constructional materials. Data concerning the melting temperature, transition temperature, latent heat of fusion, heat of transition, specific heat, and thermal conductivity of pure and commercial grades of paraffin hydrocarbons are given. An index of companies capable of producing paraffin hydrocarbons and information concerning the availability of various grades (purity levels) is provided.

  10. Dependence of Glass Mechanical Properties on Thermal and Pressure History

    DEFF Research Database (Denmark)

    Smedskjær, Morten Mattrup; Bauchy, Mathieu

    Predicting the properties of new glasses prior to manufacturing is a topic attracting great industrial and scientific interest. Mechanical properties are currently of particular interest given the increasing demand for stronger, thinner, and more flexible glasses in recent years. However, as a non......-equilibrium material, the structure and properties of glass depend not only on its composition, but also on its thermal and pressure histories. Here we review our recent findings regarding the thermal and pressure history dependence of indentation-derived mechanical properties of oxide glasses....

  11. Measurement and model on thermal properties of sintered diamond composites

    International Nuclear Information System (INIS)

    Moussa, Tala; Garnier, Bertrand; Peerhossaini, Hassan

    2013-01-01

    Highlights: ► Thermal properties of sintered diamond used for grinding is studied. ► Flash method with infrared temperature measurement is used to investigate. ► Thermal conductivity increases with the amount of diamond. ► It is very sensitive to binder conductivity. ► Results agree with models assuming imperfect contact between matrix and particles. - Abstract: A prelude to the thermal management of grinding processes is measurement of the thermal properties of working materials. Indeed, tool materials must be chosen not only for their mechanical properties (abrasion performance, lifetime…) but also for thermal concerns (thermal conductivity) for efficient cooling that avoids excessive temperatures in the tool and workpiece. Sintered diamond is currently used for grinding tools since it yields higher performances and longer lifetimes than conventional materials (mineral or silicon carbide abrasives), but its thermal properties are not yet well known. Here the thermal conductivity, heat capacity and density of sintered diamond are measured as functions of the diamond content in composites and for two types of metallic binders: hard tungsten-based and soft cobalt-based binders. The measurement technique for thermal conductivity is derived from the flash method. After pulse heating, the temperature of the rear of the sample is measured with a noncontact method (infrared camera). A parameter estimation method associated with a three-layer nonstationary thermal model is used to obtain sample thermal conductivity, heat transfer coefficient and absorbed energy. With the hard metallic binder, the thermal conductivity of sintered diamond increased by up to 64% for a diamond content increasing from 0 to 25%. The increase is much less for the soft binder: 35% for diamond volumes up to 25%. In addition, experimental data were found that were far below the value predicted by conventional analytical models for effective thermal conductivity. A possible explanation

  12. Thermal expansion properties of calcium aluminate hydrates

    International Nuclear Information System (INIS)

    Song, Tae Woong

    1986-01-01

    In order to eliminate the effect of impurities and aggregates on the thermomechanical properties of the various calcium aluminate hydrates, and to prepare clinkers in which all calcium aluminates are mixed homogeneously, chemically pure CaO and Al 2 O 3 were weighed, blended and heated in various conditions. After quantitative X-ray diffractometry(QXRD), the synthesized clinker was hydrated and cured under the conditions of 30 deg C, W/C=0.5, relative humidity> 90% respectively during 24 hours. And then differential thermal analysis(DTA), thermogravimetry(TG), micro calorimetry, thermomechanical analysis(TMA) and scanning electron microanalysis(SEM) were applied to examine the thermal properties of samples containing, calcium aluminate hydrates in various quantity. (Author)

  13. Thermal properties of lithium ceramics for fusion applications

    International Nuclear Information System (INIS)

    Hollenberg, G.W.; Baker, D.E.

    1982-03-01

    Specific heat, thermal diffusivity and thermal conductivity were measured on Li 2 O, Li 4 SiO 4 , Li 2 ZrO 3 and LiAlO 2 . Data on these properties were needed for design of an irradiation experiment to be performed on these materials. In general, the specific heat of a ceramic is primarily enrichment-dependent, but the thermal diffusivity and thermal expansion coefficient may be influenced by microstructure. Hence, it will be necessary to duplicate these measurements on the engineering materials finally selected for a particular design

  14. Thermal treatment technology at the Idaho National Engineering Laboratory

    International Nuclear Information System (INIS)

    Hillary, J.M.

    1994-01-01

    Recent surveys of mixed wastes in interim storage throughout the 30-site Department of Energy complex indicate that only 12 of those sites account for 98% of such wastes by volume. Current inventories at the Idaho National Engineering Laboratory (INEL) account for 38% of total DOE wastes in interim storage, the largest of any single site. For a large percentage of these waste volumes, as well as the substantial amounts of buried and currently generated wastes, thermal treatment processes have been designated as the technologies of choice. Current facilities and a number of proposed strategies exist for thermal treatment of wastes of this nature at the INEL. High-level radioactive waste is solidified in the Waste Calciner Facility at the Idaho Central Processing Plant. Low-level solid wastes until recently have been processed at the Waste Experimental Reduction Facility (WERF), a compaction, size reduction, and controlled air incineration facility. WERF is currently undergoing process upgrading and RCRA Part B permitting. Recent systems studies have defined effective strategies, in the form of thermal process sequences, for treatment of wastes of the complex and heterogeneous nature in the INEL inventory. This presentation reviews the current status of operating facilities, active studies in this area, and proposed strategies for thermal treatment of INEL wastes

  15. Argonne National Laboratory's thermal plume measurements: instruments and techniques

    International Nuclear Information System (INIS)

    Van Loon, L.S.; Frigo, A.A.; Paddock, R.A.

    1977-12-01

    Instrumentation and techniques were developed at Argonne National Laboratory for measuring the three-dimensional temperature structure of thermal plumes from power plants, along with the limnological, meteorological, and plant operating conditions affecting their behavior. The equipment and procedures were designed to provide field data for use in evaluating predictive models that describe thermal plume behavior, and over 100 sets of these data have been collected. The instrument systems and techniques employed in a typical thermal discharge survey are highly integrated. Continuous monitoring of ambient and plant conditions is coupled with plume mapping from a moving survey boat. The instantaneous location of the boat together with subsurface temperature measurements from a towed thermistor chain provide a quasisynoptic view of the plume structure. Real-time, onboard display of the boat path and vertical temperatures supply feedback to investigators for determining the extent and spatial resolution of measurements required. The unique design, reliability, accuracy, calibration, and historical development of the components of these integrated systems are described. Survey system interfaces with data handling and processing techniques are also explained. Special supportive studies to investigate plume dynamics, values of eddy diffusivities, time-temperature histories of water parcels in thermal plumes, and rapid changes in plume shape are also described along with instrumentation used

  16. Thermal Expansion Properties of Aerospace Materials

    Science.gov (United States)

    Green, E. F.

    1969-01-01

    Thermal expansion properties of materials used in aerospace systems are compiled into a single handbook. The data, derived from experimental measurements supplemented by information from literature sources, are presented in charts and tables arranged in two sections, covering cryogenic and elevated temperatures.

  17. Vibrational and Thermal Properties of Oxyanionic Crystals

    Science.gov (United States)

    Korabel'nikov, D. V.

    2018-03-01

    The vibrational and thermal properties of dolomite and alkali chlorates and perchlorates were studied in the gradient approximation of density functional theory using the method of a linear combination of atomic orbitals (LCAO). Long-wave vibration frequencies, IR and Raman spectra, and mode Gruneisen parameters were calculated. Equation-of-state parameters, thermodynamic potentials, entropy, heat capacity, and thermal expansion coefficient were also determined. The thermal expansion coefficient of dolomite was established to be much lower than for chlorates and perchlorates. The temperature dependence of the heat capacity at T > 200 K was shown to be generally governed by intramolecular vibrations.

  18. Thermal properties of a novel nanoencapsulated phase change material for thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Fuensanta, Mónica, E-mail: monica.fuensanta@aidico.es [AIDICO, Technological Institute of Construction, Camí de Castella, 4, 03660 Novelda, Alicante (Spain); Paiphansiri, Umaporn [Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz (Germany); Romero-Sánchez, María Dolores, E-mail: md.romero@aidico.es [AIDICO, Technological Institute of Construction, Camí de Castella, 4, 03660 Novelda, Alicante (Spain); Guillem, Celia; López-Buendía, Ángel M. [AIDICO, Technological Institute of Construction, Camí de Castella, 4, 03660 Novelda, Alicante (Spain); Landfester, Katharina [Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz (Germany)

    2013-08-10

    Highlights: • A paraffin wax RT80 was encapsulated in styrene–butyl acrylate copolymer as polymer shell using miniemulsion polymerization process to obtain a novel nanoencapsulated PCM with 80 °C melting temperature. • Nano-PCMs have high compact structure, spherical morphology and thermal stability. • The nano-PCMs have potential applications as thermal energy storage materials. - Abstract: A novel nanoencapsulation of a paraffine type phase change material, RT80, in a styrene–butyl acrylate copolymer shell using the miniemulsion polymerization process was carried out. General characteristics of the RT80 nanoparticles in terms of thermal properties, morphology, chemical composition and particle size distribution were characterized by Differential Scanning Calorimetry (DSC), Thermal Gravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR) and Dynamic Light Scattering (DLS). The influence of different monomers (styrene, butyl acrylate) and the surfactant/paraffin mass ratios on nanoparticles properties such as thermal capacity, particle size and morphology were systematically investigated. In all cases studied, encapsulation efficiency was close to 80 wt% with a particle size distribution between 52 and 112 nm and regular spherical shape and uniform structure. The amount of encapsulated paraffin achieved was comprised between 8 and 20%. Melting and crystallization heats were found to be approximately 5–25 J g{sup −1}, mainly depending on surfactant/paraffin mass ratio. Melting temperature of RT80 nanoparticles slightly decreased (1–7 °C) respect to the raw RT80. In addition, the encapsulated RT80 nanoparticles show thermal stability even after 200 thermal (heat-cooling) cycles.

  19. Thermal properties of a novel nanoencapsulated phase change material for thermal energy storage

    International Nuclear Information System (INIS)

    Fuensanta, Mónica; Paiphansiri, Umaporn; Romero-Sánchez, María Dolores; Guillem, Celia; López-Buendía, Ángel M.; Landfester, Katharina

    2013-01-01

    Highlights: • A paraffin wax RT80 was encapsulated in styrene–butyl acrylate copolymer as polymer shell using miniemulsion polymerization process to obtain a novel nanoencapsulated PCM with 80 °C melting temperature. • Nano-PCMs have high compact structure, spherical morphology and thermal stability. • The nano-PCMs have potential applications as thermal energy storage materials. - Abstract: A novel nanoencapsulation of a paraffine type phase change material, RT80, in a styrene–butyl acrylate copolymer shell using the miniemulsion polymerization process was carried out. General characteristics of the RT80 nanoparticles in terms of thermal properties, morphology, chemical composition and particle size distribution were characterized by Differential Scanning Calorimetry (DSC), Thermal Gravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR) and Dynamic Light Scattering (DLS). The influence of different monomers (styrene, butyl acrylate) and the surfactant/paraffin mass ratios on nanoparticles properties such as thermal capacity, particle size and morphology were systematically investigated. In all cases studied, encapsulation efficiency was close to 80 wt% with a particle size distribution between 52 and 112 nm and regular spherical shape and uniform structure. The amount of encapsulated paraffin achieved was comprised between 8 and 20%. Melting and crystallization heats were found to be approximately 5–25 J g −1 , mainly depending on surfactant/paraffin mass ratio. Melting temperature of RT80 nanoparticles slightly decreased (1–7 °C) respect to the raw RT80. In addition, the encapsulated RT80 nanoparticles show thermal stability even after 200 thermal (heat-cooling) cycles

  20. The effects of MWNT on thermal conductivity and thermal mechanical properties of epoxy

    Science.gov (United States)

    Ismadi, A. I.; Othman, R. N.

    2017-12-01

    Multiwall nanotube (MWNT) was used as filler in various studies to improve thermal conductivity and mechanical properties of epoxy. Present study varied different weight loading (0, 0.1 %, 0.5 %, 1 %, 1.5 %, 3 % and 5 %) of MWNT in order to observe the effects on the epoxy. Nanocomposite was analyzed by dynamic-mechanical thermal analyser (DMTA) and KD2 pro analyzer. DMTA measured storage modulus (E') and glass transition temperature (Tg) of the nanocomposite. Result showed that Tg value of neat epoxy is higher than all MWNT epoxy nanocomposite. Tg values drop from 81.55 °C (neat epoxy) to 65.03 °C (at 0.1 wt%). This may happen due to the agglomeration of MWNT in the epoxy. However, Tg values increases with the increase of MWNT wt%. Tg values increased from 65.03 °C to 78.53 °C at 1 wt%. Increment of storage modulus (E') at 3 °C (glassy region) was observed as the MWNT loading increases. Maximum value of E' during glassy region was observed to be at 5 wt% with (7.26±0.7) E+08 Pa compared to neat epoxy. On the contrary, there is slight increased and slight decreased with E' values at 100 °C (rubbery region) for all nanocomposite. Since epoxy exhibits low thermal conductivity properties, addition of MWNT has enhanced the properties. Optimum value of thermal conductivity was observed at 3 wt%. The values increased up to 9.03 % compared to neat epoxy. As expected, the result showed decrease value in thermal conductivity at 5 wt% as a result of agglomeration of MWNT in the epoxy.

  1. Mechanical and thermal properties of bulk ZrB{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Nakamori, Fumihiro [Graduate School of Engineering, Osaka University (Japan); Ohishi, Yuji, E-mail: ohishi@ms.see.eng.osaka-u.ac.jp [Graduate School of Engineering, Osaka University (Japan); Muta, Hiroaki; Kurosaki, Ken [Graduate School of Engineering, Osaka University (Japan); Fukumoto, Ken-ichi [Research Institute of Nuclear Engineering, University of Fukui (Japan); Yamanaka, Shinsuke [Graduate School of Engineering, Osaka University (Japan); Research Institute of Nuclear Engineering, University of Fukui (Japan)

    2015-12-15

    ZrB{sub 2} appears to have formed in the fuel debris at the Fukushima Daiichi nuclear disaster site, through the reaction between Zircaloy cladding materials and the control rod material B{sub 4}C. Since ZrB{sub 2} has a high melting point of 3518 K, the ceramic has been widely studied as a heat-resistant material. Although various studies on the thermochemical and thermophysical properties have been performed for ZrB{sub 2}, significant differences exist in the data, possibly due to impurities or the porosity within the studied samples. In the present study, we have prepared a ZrB{sub 2} bulk sample with 93.1% theoretical density by sintering ZrB{sub 2} powder. On this sample, we have comprehensively examined the thermal and mechanical properties of ZrB{sub 2} by the measurement of specific heat, ultrasonic sound velocities, thermal diffusivity, and thermal expansion. Vickers hardness and fracture toughness were also measured and found to be 13–23 GPa and 1.8–2.8 MPa m{sup 0.5}, respectively. The relationships between these properties were carefully examined in the present study. - Highlights: • A ZrB{sub 2} bulk sample with 93.1% theoretical density was prepared by sintering ZrB{sub 2} powder. • We have evaluated mechanical and thermal properties such as Vickers hardness, fracture toughness and thermal conductivity. • The relationships between these properties were carefully examined.

  2. Multiscale Modeling of Carbon/Phenolic Composite Thermal Protection Materials: Atomistic to Effective Properties

    Science.gov (United States)

    Arnold, Steven M.; Murthy, Pappu L.; Bednarcyk, Brett A.; Lawson, John W.; Monk, Joshua D.; Bauschlicher, Charles W., Jr.

    2016-01-01

    Next generation ablative thermal protection systems are expected to consist of 3D woven composite architectures. It is well known that composites can be tailored to achieve desired mechanical and thermal properties in various directions and thus can be made fit-for-purpose if the proper combination of constituent materials and microstructures can be realized. In the present work, the first, multiscale, atomistically-informed, computational analysis of mechanical and thermal properties of a present day - Carbon/Phenolic composite Thermal Protection System (TPS) material is conducted. Model results are compared to measured in-plane and out-of-plane mechanical and thermal properties to validate the computational approach. Results indicate that given sufficient microstructural fidelity, along with lowerscale, constituent properties derived from molecular dynamics simulations, accurate composite level (effective) thermo-elastic properties can be obtained. This suggests that next generation TPS properties can be accurately estimated via atomistically informed multiscale analysis.

  3. Thermal properties of PZT95/5(1.8Nb) and PSZT ceramics

    International Nuclear Information System (INIS)

    DiAntonio, Christopher Brian; Rae, David F.; Corelis, David J.; Yang, Pin; Burns, George Robert

    2006-01-01

    Thermal properties of niobium-modified PZT95/5(1.8Nb) and PSZT ceramics used for the ferroelectric power supply have been studied from -100 C to 375 C. Within this temperature range, these materials exhibit ferroelectric-ferroelectric and ferroelectric-paraelectric phase transformations. The thermal expansion coefficient, heat capacity, and thermal diffusivity of different phases were measured. Thermal conductivity and Grueneisen constant were calculated at several selected temperatures between -60 C and 100 C. Results show that thermal properties of these two solid solutions are very similar. Phase transformations in these ceramics possess first order transformation characteristics including thermal hysteresis, transformational strain, and enthalpy change. The thermal strain in the high temperature rhombohedral phase region is extremely anisotropic. The heat capacity for both materials approaches to 3R (or 5.938 cal/(g-mole*K)) near room temperature. The thermal diffusivity and the thermal conductivity are quite low in comparison to common oxide ceramics, and are comparable to amorphous silicate glass. Furthermore, the thermal conductivity of these materials between -60 C and 100 C becomes independent of temperature and is sensitive to the structural phase transformation. These phenomena suggest that the phonon mean free path governing the thermal conductivity in this temperature range is limited by the lattice dimensions, which is in good agreement with calculated values. Effects of small compositional changes and density/porosity variations in these ceramics on their thermal properties are also discussed. The implications of these transformation characteristics and unusual thermal properties are important in guiding processing and handling procedures for these materials

  4. Estimation of oil reservoir thermal properties through temperature log data using inversion method

    International Nuclear Information System (INIS)

    Cheng, Wen-Long; Nian, Yong-Le; Li, Tong-Tong; Wang, Chang-Long

    2013-01-01

    Oil reservoir thermal properties not only play an important role in steam injection well heat transfer, but also are the basic parameters for evaluating the oil saturation in reservoir. In this study, for estimating reservoir thermal properties, a novel heat and mass transfer model of steam injection well was established at first, this model made full analysis on the wellbore-reservoir heat and mass transfer as well as the wellbore-formation, and the simulated results by the model were quite consistent with the log data. Then this study presented an effective inversion method for estimating the reservoir thermal properties through temperature log data. This method is based on the heat transfer model in steam injection wells, and can be used to predict the thermal properties as a stochastic approximation method. The inversion method was applied to estimate the reservoir thermal properties of two steam injection wells, it was found that the relative error of thermal conductivity for the two wells were 2.9% and 6.5%, and the relative error of volumetric specific heat capacity were 6.7% and 7.0%,which demonstrated the feasibility of the proposed method for estimating the reservoir thermal properties. - Highlights: • An effective inversion method for predicting the oil reservoir thermal properties was presented. • A novel model for steam injection well made full study on the wellbore-reservoir heat and mass transfer. • The wellbore temperature field and steam parameters can be simulated by the model efficiently. • Both reservoirs and formation thermal properties could be estimated simultaneously by the proposed method. • The estimated steam temperature was quite consistent with the field data

  5. FY 2017 – Thermal Aging Effects on Advanced Structural Materials

    Energy Technology Data Exchange (ETDEWEB)

    Li, Meimei [Argonne National Lab. (ANL), Argonne, IL (United States); Natesan, K [Argonne National Lab. (ANL), Argonne, IL (United States); Chen, Wei-Ying [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-08-01

    This report provides an update on the evaluation of the effect of thermal aging on tensile properties of existing laboratory-sized heats of Alloy 709 austenitic stainless steel and the completion of effort on the thermal aging effect on the tensile properties of optimized G92 ferritic-martensitic steel. The report is a Level 3 deliverable in FY17 (M3AT-17AN1602081), under the Work Package AT-17AN160208, “Advanced Alloy Testing - ANL” performed by the Argonne National Laboratory (ANL), as part of the Advanced Reactor Technologies Program.

  6. Thermal properties of degraded lowland peat-moorsh soils

    Science.gov (United States)

    Gnatowski, Tomasz

    2016-04-01

    Soil thermal properties, i.e.: specific heat capacity (c), thermal conductivity (K), volumetric heat capacity (C) govern the thermal environment and heat transport through the soil. Hence the precise knowledge and accurate predictions of these properties for peaty soils with high amount of organic matter are especially important for the proper forecasting of soil temperature and thus it may lead to a better assessment of the greenhouse gas emissions created by microbiological activity of the peatlands. The objective of the study was to develop the predictive models of the selected thermal parameters of peat-moorsh soils in terms of their potential applicability for forecasting changes of soil temperature in degraded ecosystems of the Middle Biebrza River Valley area. Evaluation of the soil thermal properties was conducted for the parameters: specific heat capacity (c), volumetric heat capacities of the dry and saturated soil (Cdry, Csat) and thermal conductivities of the dry and saturated soil (Kdry, Ksat). The thermal parameters were measured using the dual-needle probe (KD2-Pro) on soil samples collected from seven peaty soils, representing total 24 horizons. The surface layers were characterized by different degrees of advancement of soil degradation dependent on intensiveness of the cultivation practises (peaty and humic moorsh). The underlying soil layers contain peat deposits of different botanical composition (peat-moss, sedge-reed, reed and alder) and varying degrees of decomposition of the organic matter, from H1 to H7 (von Post scale). Based on the research results it has been shown that the specific heat capacity of the soils differs depending on the type of soil (type of moorsh and type of peat). The range of changes varied from 1276 J.kg-1.K-1 in the humic moorsh soil to 1944 J.kg-1.K-1 in the low decomposed sedge-moss peat. It has also been stated that in degraded peat soils with the increasing of the ash content in the soil the value of specific heat

  7. Mechanical and thermal properties of HSC with fine natural pozzolana as SCM

    Science.gov (United States)

    KoÅ¥átková, Jaroslava; Čáchová, Monika; KoÅáková, Dana; Vejmelková, Eva; Reiterman, Pavel

    2017-07-01

    The paper is dealing with an influence of fine pozzolanic admixture supplementing a part of cement on various properties of high-strength concrete. The measured characteristics were basic physical properties, compressive strength and thermal properties (thermal conductivity and specific heat capacity). Replacing the cement by the natural pozzolana in higher dosages leads to the higher porosity and thus to the lower compressive strength of the developed material. Conversely, in case of lower amounts of pozzolana (up to 10% of weight) such replacement has an opposite consequence, the open porosity decreases which results in the higher compressive strength. Taking into account thermal properties which are enhanced by an increase of amount of pores, it is evident that it is necessary to optimize the amount of pozzolana (pozzolanic) admixture in order to obtain reasonable mechanical and thermal properties.

  8. Thermal properties and stabilities of polymer thin films

    International Nuclear Information System (INIS)

    Kanaya, Toshiji; Kawashima, Kazuko; Inoue, Rintaro; Miyazaki, Tsukasa

    2009-01-01

    Recent extensive studies have revealed that polymer thin films showed very interesting but unusual thermal properties and stabilities. In the article we show that X-ray reflectivity and neutron reflectivity are very powerful tools to study the anomalous properties of polymer thin films. (author)

  9. Thermal Properties of Algerian Diatomite, Study of the Possibility to Its Use in the Thermal Insulation

    Science.gov (United States)

    Hamdi, Boualem; Hamdi, Safia

    The chemical and physical properties of a Algerian diatomite were given before and after heat treatment and chemical with an aim of a use in the heat insulation of constructions. The preliminary results obtained showed that this material is extremely porous (porosity >70 %), characterized of a low density and a very low thermal conductivity. These promising properties support the use of this local material in the thermal insulation.

  10. A non-destructive method to measure the thermal properties of frozen soils during phase transition

    Directory of Open Access Journals (Sweden)

    Bin Zhang

    2015-04-01

    Full Text Available Frozen soils cover about 40% of the land surface on the earth and are responsible for the global energy balances affecting the climate. Measurement of the thermal properties of frozen soils during phase transition is important for analyzing the thermal transport process. Due to the involvement of phase transition, the thermal properties of frozen soils are rather complex. This paper introduces the uses of a multifunctional instrument that integrates time domain reflectometry (TDR sensor and thermal pulse technology (TPT to measure the thermal properties of soil during phase transition. With this method, the extent of phase transition (freezing/thawing was measured with the TDR module; and the corresponding thermal properties were measured with the TPT module. Therefore, the variation of thermal properties with the extent of freezing/thawing can be obtained. Wet soils were used to demonstrate the performance of this measurement method. The performance of individual modules was first validated with designed experiments. The new sensor was then used to monitor the properties of soils during freezing–thawing process, from which the freezing/thawing degree and thermal properties were simultaneously measured. The results are consistent with documented trends of thermal properties variations.

  11. Determination of in-situ thermal properties of Stripa granite from temperature measurements in the full-scale heater experiments: method and preliminary results. Technical information report No. 24

    International Nuclear Information System (INIS)

    Jeffry, J.A.; Chan, T.; Cook, N.G.W.; Witherspoon, P.A.

    1979-05-01

    The in-situ thermal conductivity and thermal diffusivity of a granite rock mass at the Stripa mine, Sweden, have been extracted from the first 70 days of temperature data for the 5 kW full-scale heater experiment by means of least-squares fit to a finite-line source solution. Thermal conductivity and thermal diffusivity have been determined to be 3.69 W/(m- 0 C) and 1.84 x 10 -6 m 2 /s, respectively, at an average rock temperature of 23 0 C (the average value of the actual temperature data used). These values are only slightly higher than the corresponding laboratory values, i.e., there is no significant size effect in the thermal properties of this rock mass. Since the size and shape of the heater canister used are similar to those considered for nuclear waste canisters and a substantial volume of rock is heated, the thermal properties obtained in this study are representative of in-situ rock mass properties under actual nuclear repository operating conditions

  12. Preparation and thermal properties of polyacrylonitrile/hexagonal boron nitride composites

    International Nuclear Information System (INIS)

    Madakbaş, Seyfullah; Çakmakçı, Emrah; Kahraman, Memet Vezir

    2013-01-01

    Highlights: ► PAN/h-BN composites with improved thermal stability were prepared. ► Thermal properties of composites were analysed by TGA and DSC. ► Flame retardancy of the composites increased up to 27%. - Abstract: Polyacrylonitrile is a thermoplastic polymer with unique properties and it has several uses. However its flammability is a major drawback for certain applications. In this study it was aimed to prepare polyacrylonitrile (PAN)/hexagonal boron nitride (h-BN) composites with improved flame retardancy and thermal stability. Chemical structures of the composites were characterized by FTIR analysis. Thermal properties of these novel composites were analysed by TGA and DSC measurements. Glass transition temperatures and char yields increased with increasing h-BN percentage. Flame retardancy of the PAN composite materials improved with the addition of h-BN and the LOI value reached to 27% from 18%. Furthermore, the surface morphology of the composites was investigated by SEM analysis.

  13. Thermal properties at Aespoe HRL. Analysis of distribution and scale factors

    International Nuclear Information System (INIS)

    Sundberg, Jan

    2003-04-01

    A thermal model for the Aespoe HRL as well as a general strategy for thermal modelling is under development. As a part of that work, thermal conductivities have been modelled from reference values of thermal conductivity of different minerals and from the mineral composition of all Aespoe samples in the Sicada database. The produced thermal conductivity database has been analysed in terms of frequency, type of distribution, spatial distribution, variogram etc. A correction factor has been estimated to compensate for discrepancies between measured and calculated values. The calculated values have been corrected according to measured values. The data has been analysed according to different rock types. However, there are uncertainties in the base material of rock classification, mainly due to problem to distinguish between Aespoe diorite and Aevroe granite, but also because of different classification systems. There is a relationship between thermal conductivity and density for the rock types at Aespoe. Equations of the relationship have been developed based on all thermal conductivity, heat capacity and density measurements. The equations have been tested on two bore holes at Aespoe with promising results. It may be possible to evaluate the spatial distribution of the thermal properties from density loggings. However, more work is needed to develop a complete model including the handling of high and low density zones. There is an insufficient knowledge in the variation of thermal properties at different scales. If the whole variation within a rock type is in the cm-m scale the thermal influence on the canister is small. This is due to the fact that the small-scale variation in thermal properties is mainly averaged out in the 5-10 m scale. If the main variation within rock types is in the 5-10 m scale there is probably a significant effect on the canister temperature. However, it is likely that the observed variation occurs in both these scales. Simulation has been

  14. A transient divided-bar method for simultaneous measurements of thermal conductivity and thermal diffusivity

    DEFF Research Database (Denmark)

    Bording, Thue Sylvester; Nielsen, Søren Bom; Balling, Niels

    2016-01-01

    and volumetric heat capacity, and thereby also thermal diffusivity, are measured simultaneously. As the density of samples is easily determined independently, specific heat capacity may also be determined. Finite element formulation provides a flexible forward solution for heat transfer across the bar...... and thermal properties are estimated by inverse Monte Carlo modelling. This methodology enables a proper quantification of experimental uncertainties on measured thermal properties. The developed methodology was applied to laboratory measurements of various materials, including a standard ceramic material......-3 %, and for diffusivity uncertainty may be reduced to about 3-5 %. The main uncertainty originates from the presence of thermal contact resistance associated with the internal interfaces of the bar. They are not resolved during inversion, and it is highly important that they are minimized by careful sample preparation....

  15. Evaluation of thermal properties of sintered beryllium oxide produced from Indian beryl ore

    International Nuclear Information System (INIS)

    Nair, Sathi R.; Ghanwat, S.J.; Patro, P.K.; Syambabu, M.; Mawal, N.E.; Mahata, T.; Sinha, P.K.

    2014-01-01

    Beryllium oxide (BeO) ceramics possess many interesting properties such as good thermal conductivity, high electrical resistivity, high chemical and thermal stability, low dielectric constant, low dielectric loss and low neutron absorption coefficient. These properties lead to its wide use in vacuum electronics technology, nuclear technology, microelectronics and photoelectron technology. The above properties depend on the purity of the material as well as density and microstructure of the sintered body. For high temperature application thermal conductivity and thermal expansion are two important parameters. In the present study, high purity fine BeO powder has been prepared by beryllate route starting with crude beryllium hydroxide. The powder has been sintered at 1550℃ and sintered samples have been evaluated for its thermal properties

  16. Tensile-property characterization of thermally aged cast stainless steels

    International Nuclear Information System (INIS)

    Michaud, W.F.; Toben, P.T.; Soppet, W.K.; Chopra, O.K.

    1994-02-01

    The effect of thermal aging on tensile properties of cast stainless steels during service in light water reactors has been evaluated. Tensile data for several experimental and commercial heats of cast stainless steels are presented. Thermal aging increases the tensile strength of these steels. The high-C Mo-bearing CF-8M steels are more susceptible to thermal aging than the Mo-free CF-3 or CF-8 steels. A procedure and correlations are presented for predicting the change in tensile flow and yield stresses and engineering stress-vs.-strain curve of cast stainless steel as a function of time and temperature of service. The tensile properties of aged cast stainless steel are estimated from known material information, i.e., chemical composition and the initial tensile strength of the steel. The correlations described in this report may be used for assessing thermal embrittlement of cast stainless steel components

  17. Review on thermal properties of nanofluids: Recent developments.

    Science.gov (United States)

    Angayarkanni, S A; Philip, John

    2015-11-01

    Nanofluids are dispersions of nanomaterials (e.g. nanoparticles, nanofibers, nanotubes, nanowires, nanorods, nanosheet, or droplets) in base fluids. Nanofluids have been a topic of great interest during the last one decade primarily due to the initial reports of anomalous thermal conductivity (k) enhancement in nanofluids with a small percentage of nanoparticles. This field has been quite controversial, with multiple reports of anomalous enhancement in thermal conductivity and many other reports of the thermal conductivity increase within the classical Maxwell mixing model. Several mechanisms have been proposed for explaining the observed enhancement in thermal conductivity. The role of Brownian motion, interfacial resistance, morphology of suspended nanoparticles and aggregating behavior is investigated both experimentally and theoretically. As the understanding of specific heat capacity of nanofluids is a prerequisite for their effective utilization in heat transfer applications, it is also investigated by many researchers. From the initial focus on thermophysical properties of nanofluids, the attention is now shifted to tailoring of novel nanofluids with large thermal conductivities. Further, to overcome the limitations of traditional heat transfer media, phase change materials (PCMs) and hybrid nanofluids are being developed as effective media for thermal energy storage. This review focuses the recent progress in nanofluids research from a heat transfer perspective. Emphasis is given for the latest work on thermal properties of nanofluids, phase change materials and hybrid nanofluids. The preparation of nanofluids by various techniques, methods of stabilization, stability measurement techniques, thermal conductivity and heat capacity studies, proposed mechanisms of heat transport, theoretical models on thermal conductivity, factors influencing k and the effect of nanoinclusions in PCM are discussed in this review. Sufficient background information is also

  18. Identification of thermal properties distribution in building wall using infrared thermography

    Science.gov (United States)

    Brouns, Jordan; Dumoulin, Jean

    2016-04-01

    In the construction sector, most of the measurements carried out from IR camera devices are exploited in a qualitative way (e.g. observation of thermal bridges). However, unless a quantitative analysis is realized, it is not possible to assess the impact of the observed phenomena. Most of research efforts and proposed solutions to identify quantified thermal properties (e.g. U-values) have to be completed, adapted to the built environment and validated in experimental and real conditions to allow quantified assessment of materials thermal properties thanks to IR camera devices [1]. We still need several steps in terms of scientific and technical developments for such technological progress. The H2020 European Built2Spec research project (http://built2spec-project.eu/) aims at giving highlights on that. Heat transfer through the walls are generally model by 1D heat equation in the wall depth. The built is composed by a multilayer domain representing the construction process. In this context, the thermal parameters of the wall are piecewise constant space functions. We propose a methodology to recover the vector of the wall thermal properties (conductivity and capacity) from boundary measurements obtained from an IR camera. It formulates as an inverse problem where the unknown are sought as minimizers of a cost function evaluating the gap between the measures and the model response. This optimization problem is non linear, and we solve it with the Levenberg-Marquardt algorithm coupled with the conjugate gradient method [2-3]. To shorten the time of the identification process, we use the adjoint method coming from the control theory [4]. This method fasten the gradient computation by solving an associated model, named the adjoint model. We study the ability of the procedure to reconstruct internal wall constitution from different environmental conditions. Furthermore, we propose a controlled experimental test to evaluate the method in laboratory conditions. References

  19. Thermophysical and Thermomechanical Properties of Thermal Barrier Coating Systems

    Science.gov (United States)

    Zhu, Dongming; Miller, Robert A.

    2000-01-01

    Thermal barrier coatings have been developed for advanced gas turbine and diesel engine applications to improve engine reliability and fuel efficiency. However, the issue of coating durability under high temperature cyclic conditions is still of major concern. The coating failure is closely related to thermal stresses and oxidation in the coating systems. Coating shrinkage cracking resulting from ceramic sintering and creep at high temperatures can further accelerate the coating failure process. The purpose of this paper is to address critical issues such as ceramic sintering and creep, thermal fatigue and their relevance to coating life prediction. Novel test approaches have been established to obtain critical thermophysical and thermomechanical properties of the coating systems under near-realistic temperature and stress gradients encountered in advanced engine systems. Emphasis is placed on the dynamic changes of the coating thermal conductivity and elastic modulus, fatigue and creep interactions, and resulting failure mechanisms during the simulated engine tests. Detailed experimental and modeling results describing processes occurring in the thermal barrier coating systems provide a framework for developing strategies to manage ceramic coating architecture, microstructure and properties.

  20. Measurement of thermal properties of white radish (R. raphanistrum using easily constructed probes.

    Directory of Open Access Journals (Sweden)

    Mfrekemfon Samuel Obot

    Full Text Available Thermal properties are necessary for the design and control of processes and storage facilities of food materials. This study proposes the measurement of thermal properties using easily constructed probes with specific heat capacity calculated, as opposed to the use of Differential Scanning Calorimeter (DSC or other. These probes were constructed and used to measure thermal properties of white radish in the temperature range of 80-20°C and moisture content of 91-6.1% wb. Results showed thermal properties were within the range of 0.71-0.111 Wm-1 C-1 for thermal conductivity, 1.869×10-7-0.72×10-8 m2s-1 for thermal diffusivity and 4.316-1.977 kJ kg-1C-1for specific heat capacity. These results agree with reports for similar products studied using DSC and commercially available line heat source probes. Empirical models were developed for each property through linear multiple regressions. The data generated would be useful in modeling and control of its processing and equipment design.

  1. Measurement of thermal properties of white radish (R. raphanistrum) using easily constructed probes.

    Science.gov (United States)

    Obot, Mfrekemfon Samuel; Li, Changcheng; Fang, Ting; Chen, Jinquan

    2017-01-01

    Thermal properties are necessary for the design and control of processes and storage facilities of food materials. This study proposes the measurement of thermal properties using easily constructed probes with specific heat capacity calculated, as opposed to the use of Differential Scanning Calorimeter (DSC) or other. These probes were constructed and used to measure thermal properties of white radish in the temperature range of 80-20°C and moisture content of 91-6.1% wb. Results showed thermal properties were within the range of 0.71-0.111 Wm-1 C-1 for thermal conductivity, 1.869×10-7-0.72×10-8 m2s-1 for thermal diffusivity and 4.316-1.977 kJ kg-1C-1for specific heat capacity. These results agree with reports for similar products studied using DSC and commercially available line heat source probes. Empirical models were developed for each property through linear multiple regressions. The data generated would be useful in modeling and control of its processing and equipment design.

  2. EXPERIMENTAL MEASUREMENT OF NANOFLUIDS THERMAL PROPERTIES

    Directory of Open Access Journals (Sweden)

    Adnan M. Hussein

    2013-07-01

    Full Text Available Solid particles dispersed in a liquid with sizes no larger than 100nm, known as nanofluids, are used to enhance Thermophysical properties compared to the base fluid. Preparations of alumina (Al2O3, titania (TiO2 and silica (SiO2 in water have been experimentally conducted in volume concentrations ranging between 1 and 2.5%. Thermal conductivity is measured by the hot wire method and viscosity with viscometer equipment. The results of thermal conductivity and viscosity showed an enhancement (0.5–20% and 0.5–60% respectively compared with the base fluid. The data measured agreed with experimental data of other researchers with deviation of less than 5%. The study showed that alumina has the highest thermal conductivity, followed silica and titania, on the other hand silica has the highest viscosity followed alumina and titania.

  3. Crystallite Size Effect on Thermal Conductive Properties of Nonwoven Nanocellulose Sheets.

    Science.gov (United States)

    Uetani, Kojiro; Okada, Takumi; Oyama, Hideko T

    2015-07-13

    The thermal conductive properties, including the thermal diffusivity and resultant thermal conductivity, of nonwoven nanocellulose sheets were investigated by separately measuring the thermal diffusivity of the sheets in the in-plane and thickness directions with a periodic heating method. The cross-sectional area (or width) of the cellulose crystallites was the main determinant of the thermal conductive properties. Thus, the results strongly indicate that there is a crystallite size effect on phonon conduction within the nanocellulose sheets. The results also indicated that there is a large interfacial thermal resistance between the nanocellulose surfaces. The phonon propagation velocity (i.e., the sound velocity) within the nanocellulose sheets was estimated to be ∼800 m/s based on the relationship between the thermal diffusivities and crystallite widths. The resulting in-plane thermal conductivity of the tunicate nanocellulose sheet was calculated to be ∼2.5 W/mK, markedly higher than other plastic films available for flexible electronic devices.

  4. The Thermal Properties of CM Carbonaceous Chondrites

    Science.gov (United States)

    Britt, D. T.; Opeil, C.

    2017-12-01

    The physical properties of asteroid exploration targets are fundamental parameters for developing models, planning observations, mission operations, reducing operational risk, and interpreting mission results. Until we have returned samples, meteorites represent our "ground truth" for the geological material we expect to interact with, sample, and interpret on the surfaces of asteroids. The physical properties of the volatile-rich carbonaceous chondrites (CI, C2, CM, and CR groups) are of particular interest because of their high resource potential. We have measured the thermal conductivity, heat capacity and thermal expansion of five CM carbonaceous chondrites (Murchison, Murray, Cold Bokkeveld, NWA 7309, Jbilet Winselwan) at low temperatures (5-300 K) to mimic the conditions in the asteroid belt. The mineralogy of these meteorites are dominated by abundant hydrous phyllosilicates, but also contain anhydrous minerals such as olivine and pyroxene found in chondrules. The thermal expansion measurements for all these CMs indicate a substantial increase in meteorite volume as temperature decreases from 230 - 210 K followed by linear contraction below 210 K. Such transitions were unexpected and are not typical for anhydrous carbonaceous chondrites or ordinary chondrites. Our thermal diffusivity results compare well with previous estimates for similar meteorites, where conductivity was derived from diffusivity measurements and modeled heat capacities; our new values are of a higher precision and cover a wider range of temperatures.

  5. Measurements of thermal properties of rocks

    International Nuclear Information System (INIS)

    Kumada, Toshiaki

    2001-02-01

    The report concerns the measurement of thermal conductivity and specific heat of supplied sedimental rock B and Funyu rock. The method of measurement of these properties was done with the method which was developed at 1997 and improved much in its accuracy by the present author et al. The porosity of sedimental rock B is 0.55, which is deduced from the density of rock (the porosity deduced from the difference between dry and water filled conditions is 0.42) and the shape and size of pores in rock are much different. Its thermal conductivity is 0.238 W/mK in dry and 1.152 W/mK in water filled conditions respectively, while the thermal conductivity of bentonite is 0.238 W/mK in dry and 1.152 W/mK in water saturated conditions. The difference of thermal conductivity between dry and water saturated conditions is little difference in sedimental rock B and bentonite at same porosity. The porosity of Funyu rock is 0.26 and the shape and size of pores in the rock are uniform. Its thermal conductivity is 0.914 W/mK in dry and 1.405 W/mK in water saturated conditions, while the thermal conductivity of bentonite is 0.606 W/mK in dry and 1.591 W/mK in water saturated conditions respectively. The correlation estimating thermal conductivity of rocks was derived based on Fricke correlation by presuming rocks as a suspension. (author)

  6. Influence of Diatomite and Mineral Powder on Thermal Oxidative Ageing Properties of Asphalt

    Directory of Open Access Journals (Sweden)

    Yongchun Cheng

    2015-01-01

    Full Text Available Ageing of asphalt affects the performances of asphalt pavement significantly. Therefore, effects of diatomite and mineral powder on ageing properties of asphalt were investigated systematically in order to improve the antiageing property of mixture. Thin film oven test (TFOT was used to conduct the short term ageing in laboratory. Softening points, penetrations, force ductility, low temperature creep properties, and viscosities of asphalt mastics were tested before and after TFOT, respectively. Results indicated that percent retained penetration (PRP increased with the increasing of fillers. Increment of softening point (ΔT, ductility retention rate (DRR, deformation energy ageing index (JAI, and viscosity ageing index (VAI of asphalt mastics nonlinearly decreased with the increasing of fillers. Ageing of asphalt was reduced by diatomite and mineral powder. And the antiageing effect of diatomite was better than that of mineral powder as a result of its porous structure. It is suggested that the mineral powder could be reasonably replaced by diatomite in order to reduce thermal oxidative ageing of asphalt mixture. The optimal content of diatomite 12.8% is also suggested for engineering.

  7. University Physics Students' Ideas of Thermal Radiation Expressed in Open Laboratory Activities Using Infrared Cameras

    Science.gov (United States)

    Haglund, Jesper; Melander, Emil; Weiszflog, Matthias; Andersson, Staffan

    2017-01-01

    Background: University physics students were engaged in open-ended thermodynamics laboratory activities with a focus on understanding a chosen phenomenon or the principle of laboratory apparatus, such as thermal radiation and a heat pump. Students had access to handheld infrared (IR) cameras for their investigations. Purpose: The purpose of the…

  8. Comments on Thermal Physical Properties Testing Methods of Phase Change Materials

    Directory of Open Access Journals (Sweden)

    Jingchao Xie

    2013-01-01

    Full Text Available There is no standard testing method of the thermal physical properties of phase change materials (PCM. This paper has shown advancements in this field. Developments and achievements in thermal physical properties testing methods of PCM were commented, including differential scanning calorimetry, T-history measurement, the water bath method, and differential thermal analysis. Testing principles, advantages and disadvantages, and important points for attention of each method were discussed. A foundation for standardized testing methods for PCM was made.

  9. Thermal properties of graphene from path-integral simulations

    Science.gov (United States)

    Herrero, Carlos P.; Ramírez, Rafael

    2018-03-01

    Thermal properties of graphene monolayers are studied by path-integral molecular dynamics simulations, which take into account the quantization of vibrational modes in the crystalline membrane and allow one to consider anharmonic effects in these properties. This system was studied at temperatures in the range from 12 to 2000 K and zero external stress, by describing the interatomic interactions through the LCBOPII effective potential. We analyze the internal energy and specific heat and compare the results derived from the simulations with those yielded by a harmonic approximation for the vibrational modes. This approximation turns out to be rather precise up to temperatures of about 400 K. At higher temperatures, we observe an influence of the elastic energy due to the thermal expansion of the graphene sheet. Zero-point and thermal effects on the in-plane and "real" surface of graphene are discussed. The thermal expansion coefficient α of the real area is found to be positive at all temperatures, in contrast to the expansion coefficient αp of the in-plane area, which is negative at low temperatures and becomes positive for T ≳ 1000 K.

  10. Tailoring Thermal Radiative Properties with Doped-Silicon Nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhuomin [Georgia Inst. of Technology, Atlanta, GA (United States)

    2017-08-28

    Aligned doped-silicon nanowire (D-SiNW) arrays form a hyperbolic metamaterial in the mid-infrared and have unique thermal radiative properties, such as broadband omnidirectional absorption, low-loss negative refraction, etc. A combined theoretical and experimental investigation will be performed to characterize D-SiNW arrays and other metamaterials for tailoring thermal radiative properties. Near-field thermal radiation between anisotropic materials with hyperbolic dispersions will also be predicted for potential application in energy harvesting. A new kind of anisotropic metamaterial with a hyperbolic dispersion in a broad infrared region has been proposed and demonstrated based on aligned doped-silicon nanowire (D-SiNW) arrays. D-SiNW-based metamaterials have unique thermal radiative properties, such as broadband omnidirectional absorption whose width and location can be tuned by varying the filling ratio and/or doping level. Furthermore, high figure of merit (FOM) can be achieved in a wide spectral region, suggesting that D-SiNW arrays may be used as a negative refraction material with much less loss than other structured materials, such as layered semiconductor materials. We have also shown that D-SiNWs and other nanostructures can significantly enhance near-field thermal radiation. The study of near-field radiative heat transfer between closely spaced objects and the electromagnetic wave interactions with micro/nanostructured materials has become an emerging multidisciplinary field due to its importance in advanced energy systems, manufacturing, local thermal management, and high spatial resolution thermal sensing and mapping. We have performed extensive study on the energy streamlines involving anisotropic metamaterials and the applicability of the effective medium theory for near-field thermal radiation. Graphene as a 2D material has attracted great attention in nanoelectronics, plasmonics, and energy harvesting. We have shown that graphene can be used to

  11. Comparison of organic emissions from laboratory and full-scale thermal degradation of sewage sludge

    International Nuclear Information System (INIS)

    Tirey, D.A.; Striebich, R.C.; Dellinger, B.; Bostian, H.E.

    1991-01-01

    Samples of sewage sludge burned at one fluidized-bed and three multiple-hearth incinerators were subjected to laboratory flow reactor thermal decomposition testing in both pyrolytic and oxidative atmospheres. The time/temperature conditions of the laboratory testing were established to simulate as closely as possible full-scale incineration conditions so that a direct comparison of results could be made. The laboratory test results indicated that biomass decomposition products, not toxic industrial contaminants, comprised the majority of the emissions. Benzene, toluene, ethylbenzene, acrylonitrile, and acetonitrile were consistently the most environmentally significant products of thermal degradation. Comparison of the results from this study with those obtained in field tests was complicated by an apparent loss of volatile chlorocarbons from the sludge samples received for laboratory testing. However, qualitative comparison of emission factors derived from lab and field results for those compounds observed in both studies, showed reasonably good correlation for the pyrolysis testing. Results suggested that the upper stages of multiple-hearth units may vaporize many volatile components of the sludge before they enter the combustion stages of the incinerator and thus represent a direct source of introduction of pollutants into the atmosphere

  12. Thermal properties of perovskite RCeO{sub 3} (R = Ba, Sr)

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, Aarti, E-mail: aarti.phy@gmail.com [Department of Physics, Barkatullah University, Bhopal 462026 (India); Parey, Vanshree; Thakur, Rasna [Department of Physics, Barkatullah University, Bhopal 462026 (India); Srivastava, Archana [Department of Physics, Sri Sathya Sai College for women, Bhopal 462024 (India); Gaur, N.K. [Department of Physics, Barkatullah University, Bhopal 462026 (India)

    2015-08-20

    Highlights: • (Ba,Sr)CeO{sub 3} are high temperature protonic conductor materials. • This makes their thermal properties very interesting. • MRIM has successfully predicted the thermodynamic properties. • The computed results are in good agreement with the available experimental data. • Present results will serve as guide to experimental workers in future. - Abstract: We have investigated the bulk modulus and thermal properties of proton conducting perovskite RCeO{sub 3} (R = Ba, Sr) for the first time by incorporating the effect of lattice distortion in modified rigid ion models (MRIM). The computed bulk modulus, specific heat, thermal expansion coefficient and other thermal properties of BaCeO{sub 3} and SrCeO{sub 3} reproduce well with the available experimental data. In addition the cohesive energy (ϕ), molecular force constant (f), reststrahlen frequency (ν), Debye temperature (θ{sub D}) and Gruneisen parameter (γ) are also reported and discussed. The specific heat results can further be improved by taking into account the spin and the orbital ordering contribution in the specific heat formulae.

  13. Adsorption properties of thermally sputtered calcein film

    Science.gov (United States)

    Kruglenko, I.; Burlachenko, J.; Kravchenko, S.; Savchenko, A.; Slabkovska, M.; Shirshov, Yu.

    2014-05-01

    High humidity environments are often found in such areas as biotechnology, food chemistry, plant physiology etc. The controlling of parameters of such ambiences is vitally important. Thermally deposited calcein films have extremely high adsorptivity at exposure to water vapor of high concentration. This feature makes calcein a promising material for humidity sensing applications. The aim of this work is to explain high sensitivity and selectivity of calcein film to high humidity. Quartz crystal microbalance sensor, AFM and ellipsometry were used for calcein film characterization and adsorption properties investigation. The proposed model takes into account both the molecular properties of calcein (the presence of several functional groups capable of forming hydrogen bonds, and their arrangement) and the features of structure of thermally deposited calcein film (film restructuring due to the switching of bonds "calcein-calcein" to "calcein-water" in the course of water adsorption).

  14. Spray freeze-dried nanofibrillated cellulose aerogels with thermal superinsulating properties.

    Science.gov (United States)

    Jiménez-Saelices, Clara; Seantier, Bastien; Cathala, Bernard; Grohens, Yves

    2017-02-10

    Nanofibrillated cellulose (NFC) aerogels were prepared by spray freeze-drying (SFD). Their structural, mechanical and thermal insulation properties were compared to those of NFC aerogels prepared by conventional freeze-drying (CFD). The purpose of this investigation is to develop superinsulating bioaerogels by reducing their pore size. Severe reduction of the aerogel pore size and skeleton architecture were observed by SEM, aerogels prepared by SFD method show a fibril skeleton morphology, which defines a mesoporous structure. BET analyses confirm the appearance of a new organization structure with pores of nanometric sizes. As a consequence, the thermal insulation properties were significantly improved for SFD materials compared to CFD aerogel, reaching values of thermal conductivity as low as 0.018W/(mK). Moreover, NFC aerogels have a thermal conductivity below that of air in ambient conditions, making them one of the best cellulose based thermal superinsulating material. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Thermal stability of morpholine, AMP and sarcosine in PWR secondary systems. Laboratory and loop experiments

    International Nuclear Information System (INIS)

    Feron, D.; Lambert, I.

    1991-01-01

    Laboratory and loop tests have been carried out in order to investigate the thermal stability of three amines (morpholine, AMP and sarcosine) in PWR secondary conditions. Laboratory experiments have been performed in a titanium autoclave at 300 deg C. The results pointed out high thermal decomposition rates of AMP and sarcosine. A decomposition mechanism is proposed for the 3 amines. Loop tests have been performed in order to compare steam cycle conditioning with ammonia, morpholine and AMP. The amine concentrations and the decomposition products such as acetate and formate have been followed around the secondary circuit of the ORION loop which reproduces the main physico-chemical characteristics of a PWR secondary circuit. These concentrations are reported together with the evolution of cationic conductivities. The influence of oxygen concentration on amine thermal stability has been observed. Results are expressed also in terms of decomposition rates and of relative volatility

  16. Thermal properties of paramagnetic solid helium 3

    International Nuclear Information System (INIS)

    Goldstein, L.

    1983-01-01

    It was shown in recent work that over a limited molar volume range and at asymptotically high temperatures the thermal modulations of the pressure along isochores of paramagnetic solid 3 He could be accounted for through the formalism of the Heisenberg model of an antiferromagnetically interacting localized spin- 1/2 system. The internal consistency of this formalism requires the characteristic exchange-interaction parameter of the model derived from pressure modulation data to be identical with that appearing in the other thermal properties of this quantum solid. In a restricted temperature region where the spin excitations are the dominant thermal excitations of the solid, heat capacity data yield exchange-interaction parameters in fair agreement with those derived from pressures along isochores of larger molar volume. At higher temperatures, within well-defined limitations, thermal excitations involve both spin and phononexcitations. Here, because of the opposite temperature variations of the spin and phonon heat capacity components, the ensuing heat capacity minimum determines exactly the exchange-energy parameter and the relevant limiting Debye temperature as a function of the measured temperature location and value of the heat capacity extremum along the experimentally explored isochore. The exchange-energy parameters so derived display larger deviations from their predicted pressure-based values than those resulting from the lower temperature but still asymptotic spin-only heat capacities. At the present time, ambiguities in the experimental determinations of the characteristic Weiss temperatures of the asymptotic paramagnetic susceptibilities prevent one from deriving exchange-energy parameters with them. The present work leads to the prediction, within the limitations of the model formalism, of thermal properties of magnetized solid 3 He

  17. Tabulated In-Drift Geometric and Thermal Properties Used In Drift-Scale Models for TSPA-SR

    International Nuclear Information System (INIS)

    N.D. Francis

    2000-01-01

    The objective of this calculation is to provide in-drift physical properties required by the drift-scale models (both two- and three-dimensional) used in total system performance assessments (TSPA). The physical properties include waste package geometry, waste package thermal properties, emplacement drift geometry including backfill and invert geometry and properties (both thermal and hydrologic), drip shield geometry and thermal properties, all tabulated in a single source

  18. Improved dielectric properties, mechanical properties, and thermal conductivity properties of polymer composites via controlling interfacial compatibility with bio-inspired method

    Science.gov (United States)

    Ruan, Mengnan; Yang, Dan; Guo, Wenli; Zhang, Liqun; Li, Shuxin; Shang, Yuwei; Wu, Yibo; Zhang, Min; Wang, Hao

    2018-05-01

    Surface functionalization of Al2O3 nano-particles by mussel-inspired poly(dopamine) (PDA) was developed to improve the dielectric properties, mechanical properties, and thermal conductivity properties of nitrile rubber (NBR) matrix. As strong adhesion of PDA to Al2O3 nano-particles and hydrogen bonds formed by the catechol groups of PDA and the polar acrylonitrile groups of NBR, the dispersion of Al2O3-PDA/NBR composites was improved and the interfacial force between Al2O3-PDA and NBR matrix was enhanced. Thus, the Al2O3-PDA/NBR composites exhibited higher dielectric constant, better mechanical properties, and larger thermal conductivity comparing with Al2O3/NBR composites at the same filler content. The largest thermal conductivity of Al2O3-PDA/NBR composite filled with 30 phr Al2O3-PDA was 0.21 W/m K, which was 122% times of pure NBR. In addition, the Al2O3-PDA/NBR composite filled with 30 phr Al2O3-PDA displayed a high tensile strength about 2.61 MPa, which was about 255% of pure NBR. This procedure is eco-friendly and easy handling, which provides a promising route to polymer composites in application of thermal conductivity field.

  19. Thermal Exposure Effects on Properties of Al-Li Alloy Plate Products

    Science.gov (United States)

    Shah, Sandeep; Wells, Douglas; Wagner, John; Babel, Henry

    2003-01-01

    The objective of this viewgraph representation is to evaluate the effects of thermal exposure on the mechanical properties of both production mature and developmental Al-Li alloys. The researchers find for these alloys, the data clearly shows that there is no deficit in mechanical properties at lower exposure temperatures in some cases, and a signficant deficit in mechanical properties at higher exposure temperatures in all cases. Topics considered include: Al-Li alloys composition, key characteristics of Al-Li alloys and thermal exposure matrix.

  20. Thermal, epithermal and thermalized neutron attenuation properties of ilmenite-serpentine heat resistant concrete shield

    International Nuclear Information System (INIS)

    Kany, A.M.I.; El-Gohary, M.I.; Kamal, S.M.

    1994-01-01

    Experimental measurements were carried out to study the attenuation properties of low-energy neutrons transmitted through unheated and preheated barriers of heavy-weight, highly hydrated and heat-resistant concrete shields. The concrete shields under investigation have been prepared from naturally occurring ilmenite and serpentine Egyptian ores. A collimated beam obtained from an Am-Be source was used as a source of neutrons, while the measurements of total thermal, epithermal, and thermalized neutron fluxes were performed using a BF-3 detector, multichannel analyzer and Cd filter. Results show that the ilmenite-serpentine concrete proved to be a better thermal, epithermal and thermalized neutron attenuator than the ordinary concrete especially at a high temperature of concrete exposure. (Author)

  1. Bread making properties of wheat flour supplemented with thermally processed hypoallergenic lupine flour

    Energy Technology Data Exchange (ETDEWEB)

    Guillamon, E.; Cuadrado, C.; Pedrosa, M. M.; Varela, A.; Cabellos, B.

    2010-07-01

    In recent years there has been increased interest in using lupine for human nutrition due to its nutritional properties and health benefits. Moreover, lupine is used as an ingredient in bread making because of its functional and technological properties. However, a higher number of allergic reactions to this legume have recently been reported as a consequence of a more widespread consumption of lupine-based foods. In a previous study, several thermal treatments were applied to lupine seeds and flours resulting in reduced allergenicity. In order to study how this thermal processing (autoclaving and boiling) affects the bread making properties, raw and thermally processed lupine flours were used to replace 10% of wheat flour. The effect of supplementing wheat flour with lupine flour on physical dough properties, bread structure and sensory characteristics were analysed. The results indicated that thermally-treated lupine flours, had similar bread making and sensorial properties as untreated lupine flour. These thermal treatments could increase the potential use of lupine flour as a food ingredient while reducing the risk to provoke allergic reactions. (Author) 36 refs.

  2. Linking Aerosol Optical Properties Between Laboratory, Field, and Model Studies

    Science.gov (United States)

    Murphy, S. M.; Pokhrel, R. P.; Foster, K. A.; Brown, H.; Liu, X.

    2017-12-01

    The optical properties of aerosol emissions from biomass burning have a significant impact on the Earth's radiative balance. Based on measurements made during the Fourth Fire Lab in Missoula Experiment, our group published a series of parameterizations that related optical properties (single scattering albedo and absorption due to brown carbon at multiple wavelengths) to the elemental to total carbon ratio of aerosols emitted from biomass burning. In this presentation, the ability of these parameterizations to simulate the optical properties of ambient aerosol is assessed using observations collected in 2017 from our mobile laboratory chasing wildfires in the Western United States. The ambient data includes measurements of multi-wavelength absorption, scattering, and extinction, size distribution, chemical composition, and volatility. In addition to testing the laboratory parameterizations, this combination of measurements allows us to assess the ability of core-shell Mie Theory to replicate observations and to assess the impact of brown carbon and mixing state on optical properties. Finally, both laboratory and ambient data are compared to the optical properties generated by a prominent climate model (Community Earth System Model (CESM) coupled with the Community Atmosphere Model (CAM 5)). The discrepancies between lab observations, ambient observations and model output will be discussed.

  3. Thermal conduction properties of Mo/Si multilayers for extreme ultraviolet optics

    Science.gov (United States)

    Bozorg-Grayeli, Elah; Li, Zijian; Asheghi, Mehdi; Delgado, Gil; Pokrovsky, Alexander; Panzer, Matthew; Wack, Daniel; Goodson, Kenneth E.

    2012-10-01

    Extreme ultraviolet (EUV) lithography requires nanostructured optical components, whose reliability can be influenced by radiation absorption and thermal conduction. Thermal conduction analysis is complicated by sub-continuum electron and phonon transport and the lack of thermal property data. This paper measures and interprets thermal property data, and their evolution due to heating exposure, for Mo/Si EUV mirrors with 6.9 nm period and Mo/Si thickness ratios of 0.4/0.6 and 0.6/0.4. We use time-domain thermoreflectance and the 3ω method to estimate the thermal resistance between the Ru capping layer and the Mo/Si multilayers (RRu-Mo/Si = 1.5 m2 K GW-1), as well as the out-of-plane thermal conductivity (kMo/Si 1.1 W m-1 K-1) and thermal anisotropy (η = 13). This work also reports the impact of annealing on thermal conduction in a co-deposited MoSi2 layer, increasing the thermal conductivity from 1.7 W m-1 K-1 in the amorphous phase to 2.8 W m-1 K-1 in the crystalline phase.

  4. Study of thermal and mechanical properties of PCL films

    International Nuclear Information System (INIS)

    Siqueira, A.R. de; Vieira, A.B. da Silva; Leite, I.F.

    2016-01-01

    In the current situation of the market, it is remarkable the concern for the development of materials that offer better properties and biodegradable behavior. The scientific researches seeks development and improvement of materials for applications in products increasingly biodegradable. To do so, this research aims at obtaining films composed of polymer poly(ε-caprolactone)(PCL), aliphatic polyester synthetic and biodegradable, and silicates in layers, specifically in the State of Paraiba, prepared by the method of solution. This mixture makes it possible to form different nanostructures intercalated morphology and/or exfoliated, which therefore provides improvement in the thermal properties of the final product. After analyzing the results of X-ray diffraction (XRD) was observed predominantly exfoliated morphologies to PCL films containing different silicate content and an increase in thermal stability when there was a lower concentration of clay as thermal analysis (TGA). (author)

  5. Proper laboratory notebook practices: protecting your intellectual property.

    Science.gov (United States)

    Nickla, Jason T; Boehm, Matthew B

    2011-03-01

    A laboratory notebook contains a wealth of knowledge that can be critical for establishing evidence in support of intellectual property rights and for refuting claims of research misconduct. The proper type, organization, use, maintenance, and storage of laboratory notebooks should be a priority for everyone at research institutions. Failure to properly document research activities can lead to serious problems, including the loss of valuable patent rights. Consequences of improper laboratory notebook practices can be harsh; numerous examples are described in court cases and journal articles, indicating a need for research institutions to develop strict policies on the proper use and storage of research documentation.

  6. Electronic properties of thermally formed thin iron oxide films

    International Nuclear Information System (INIS)

    Wielant, J.; Goossens, V.; Hausbrand, R.; Terryn, H.

    2007-01-01

    The oxide layer, present between an organic coating and the substrate, guarantees adhesion of the coating and plays a determinating role in the delamination rate of the organic coating. The purpose of this study is to compare the resistive and semiconducting properties of thermal oxides formed on steel in two different atmospheres at 250 deg. C: an oxygen rich atmosphere, air, and an oxygen deficient atmosphere, N 2 . In N 2 , a magnetite layer grows while in air a duplex oxide film forms composed by an inner magnetite layer and a thin outer hematite scale. The heat treatment for different amounts of time at high temperature was used as method to sample the thickness variation and change in electronic and semiconducting properties of the thermal oxide layers. Firstly, linear voltammetric measurements were performed to have a first insight in the electrochemical behavior of the thermal oxides in a borate buffer solution. Electrochemical impedance spectroscopy in the same buffer combined with the Mott-Schottky analysis were used to determine the semiconducting properties of the thermal oxides. By spectroscopic ellipsometry (SE) and atomic force microscopy (AFM), respectively, the thickness and roughness of the oxide layers were determined supporting the physical interpretation of the voltammetric and EIS data. These measurements clearly showed that oxide layers with different constitution, oxide resistance, flatband potential and doping concentration can be grown by changing the atmosphere

  7. Mechanical, thermal, and barrier properties of methylcellulose/cellulose nanocrystals nanocomposites

    Directory of Open Access Journals (Sweden)

    Hudson Alves Silvério

    2014-12-01

    Full Text Available In this work, the effects of incorporating cellulose nanocrystals from soy hulls (WSH30 on the mechanical, thermal, and barrier properties of methylcellulose (MC nanocomposites were evaluated. MC/WSH30 nanocomposite films with different filler levels (2, 4, 6, 8, and 10% were prepared by casting. Compared to neat MC film, improvements in the mechanical and barrier properties were observed, while thermal stability was retained. The improved mechanical properties of nanocomposites prepared may be attributed to mechanical percolation of WSH30, formation of a continuous network of WSH30 linked by hydrogen interactions and a close association between filler and matrix.

  8. Mechanical, thermal, and barrier properties of methylcellulose/cellulose nanocrystals nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Silverio, Hudson Alves; Flauzino Neto, Wilson Pires; Silva, Ingrid Souza Vieira da; Rosa, Joyce Rover; Pasquini, Daniel, E-mail: pasquini@iqufu.ufu.br, E-mail: danielpasquini2005@yahoo.com.br [Universidade de Uberlandia (USU), MG (Brazil). Instituto de Quimica; Assuncao, Rosana Maria Nascimento de [Universidade de Uberlandia (USU), Ituiutaba, MG (brazil). Fac. de Ciencias Integradas do Pontal; Barud, Hernane da Silva; Ribeiro, Sidney Jose Lima [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Araraquara, SP (Brazil). Instituto de Quimica

    2014-11-15

    In this work, the effects of incorporating cellulose nanocrystals from soy hulls (WSH{sub 30}) on the mechanical, thermal, and barrier properties of methylcellulose (MC) nanocomposites were evaluated. MC/WSH{sub 30} nanocomposite films with different filler levels (2, 4, 6, 8, and 10%) were prepared by casting. Compared to neat MC film, improvements in the mechanical and barrier properties were observed, while thermal stability was retained. The improved mechanical properties of nanocomposites prepared may be attributed to mechanical percolation of WSH{sub 30}, formation of a continuous network of WSH{sub 30} linked by hydrogen interactions and a close association between filler and matrix. (author)

  9. Entanglement properties of boundary state and thermalization

    Science.gov (United States)

    Guo, Wu-zhong

    2018-06-01

    We discuss the regularized boundary state {e}^{-{τ}_0H}\\Big|{.B>}_a on two aspects in both 2D CFT and higher dimensional free field theory. One is its entanglement and correlation properties, which exhibit exponential decay in 2D CFT, the parameter 1 /τ 0 works as a mass scale. The other concerns with its time evolution, i.e., {e}^{-itH}{e}^{-{τ}_0H}\\Big|{.B>}_a . We investigate the Kubo-Martin-Schwinger (KMS) condition on correlation function of local operators to detect the thermal properties. Interestingly we find the correlation functions in the initial state {e}^{-{τ}_0H}\\Big|{.B>}_a also partially satisfy the KMS condition. In the limit t → ∞, the correlators will exactly satisfy the KMS condition. We generally analyse quantum quench by a pure state and obtain some constraints on the possible form of 2-point correlation function in the initial state if assuming they satisfies KMS condition in the final state. As a byproduct we find in an large τ 0 limit the thermal property of 2-point function in {e}^{-{τ}_0H}\\Big|{.B>}_a also appears.

  10. Consistency in thermophysical properties: enthalpy, heat capacity, thermal conductivity and thermal diffusivity of solid UO2

    International Nuclear Information System (INIS)

    Fink, J.K.; Chasanov, M.G.; Leibowitz, L.

    Equations have been derived for the enthalpy, heat capacity, thermal conductivity, and thermal diffusivity of UO 2 . In selection of these equations, we considered the traditional criterion of lowest relative standard deviation between experimental data and the function chosen to fit these data as well as consistency between the thermophysical properties. In the latter case, we considered consistency in (1) thermodynamic relations among properties, (2) the choice of physical phenomena on which to base the theoretical formulation of the equations, and (3) the existence and temperature of phase transitions

  11. A study on thermal properties of biodegradable polymers using photothermal methods

    Science.gov (United States)

    Siqueira, A. P. L.; Poley, L. H.; Sanchez, R.; da Silva, M. G.; Vargas, H.

    2005-06-01

    In this work is reported the use of photothermal techniques applied to the thermal characterization of biodegradable polymers of Polyhydroxyalkanoates (PHAs) family. This is a family of polymer produced by bacteria using renewable resources. It exhibits thermoplastic properties and therefore it can be an alternative product for engineering plastics, being also applied as packages for food industry and fruits. Thermal diffusivities were determined using the open photoacoustic cell (OPC) configuration. Specific heat capacity measurements were performed monitoring temperature of the samples under white light illumination against time. Typical values obtained for the thermal properties are in good agreement with those found in the literature for other polymers. Due to the incorporation of hydroxyvalerate in the monomer structure, the thermal diffusivity and thermal conductivity increase reaching a saturation value, otherwise the specific thermal capacity decreases as the concentration of the hydroxyvalerate (HV) increases. These results can be explained by polymers internal structure and are allowing new applications of these materials.

  12. Measurement of Thermal Properties of Triticale Starch Films Using Photothermal Techniques

    Science.gov (United States)

    Correa-Pacheco, Z. N.; Cruz-Orea, A.; Jiménez-Pérez, J. L.; Solorzano-Ojeda, S. C.; Tramón-Pregnan, C. L.

    2015-06-01

    Nowadays, several commercially biodegradable materials have been developed with mechanical properties similar to those of conventional petrochemical-based polymers. These materials are made from renewable sources such as starch, cellulose, corn, and molasses, being very attractive for numerous applications in the plastics, food, and paper industries, among others. Starches from maize, rice, wheat, and potato are used in the food industry. However, other types of starches are not used due to their low protein content, such as triticale. In this study, starch films, processed using a single screw extruder with different compositions, were thermally and structurally characterized. The thermal diffusivity, thermal effusivity, and thermal conductivity of the biodegradable films were determined using photothermal techniques. The thermal diffusivity was measured using the open photoacoustic cell technique, and the thermal effusivity was obtained by the photopyroelectric technique in an inverse configuration. The results showed differences in thermal properties for the films. Also, the films microstructures were observed by scanning electron microscopy, transmission electron microscopy, and the crystalline structure determined by X-ray diffraction.

  13. Investigation on Thermal Properties of Kenaf Fibre Reinforced Polyurethane Bio-Composites

    Science.gov (United States)

    Athmalingam, Mathan; Vicki, W. V.

    2018-01-01

    This research focuses on the effect of Kenaf fibre on thermal properties of Polyurethane (PU) reinforced kenaf bio-composites. The samples were prepared using the polymer casting method with different percentages of kenaf fibre content (5 wt%, 10 wt%, 15 wt%). The thermal properties of Kenaf/PU bio-composite are determined through the Thermogravimetric Analysis and Differential Scanning Calorimeter test. The TGA results revealed that 10 wt% Kenaf/PU bio-composite appeared to be more stable. DSC results show that the glass transition temperature (Tg) value of 10 wt% Kenaf/PU composite is significant to pure polyurethane. It can be said that the thermal stability of 10 wt% Kenaf/PU bio-composite exhibits higher thermal stability compared to other samples.

  14. Thermal and Mechanical Properties of UO2 and PuO2

    International Nuclear Information System (INIS)

    Kato, M.; Matsumoto, T.

    2015-01-01

    It is important to evaluate basic properties of UO 2 and PuO 2 as fundamental aspects of MA-bearing MOX fuel development. In this work, mechanical properties of UO 2 and PuO 2 were investigated by an ultrasound pulse-echo method. Longitudinal and transversal wave velocities were measured in UO 2 and PuO 2 pellets, and Young's modulus and shear modulus were evaluated, which were 219 MPa and 89 MPa for PuO 2 , and 249 MPa and 95 MPa for UO 2 , respectively. Poisson's ratio was 0.32 in both materials. The relationship between mechanical and thermal properties was described by using thermal expansion data which had been reported previously, and the heat capacity and thermal conductivity were analysed. (authors)

  15. Effects of ageing and moisture content on thermal properties of ...

    African Journals Online (AJOL)

    Effects of ageing and moisture content on thermal properties of cassava roots ... after harvest coupled with non-‐availability of acceptable storage alternatives. ... the properties simultaneously based on the transient line heat source method.

  16. Experimental evaluation of the thermal properties of two tissue equivalent phantom materials.

    Science.gov (United States)

    Craciunescu, O I; Howle, L E; Clegg, S T

    1999-01-01

    Tissue equivalent radio frequency (RF) phantoms provide a means for measuring the power deposition of various hyperthermia therapy applicators. Temperature measurements made in phantoms are used to verify the accuracy of various numerical approaches for computing the power and/or temperature distributions. For the numerical simulations to be accurate, the electrical and thermal properties of the materials that form the phantom should be accurately characterized. This paper reports on the experimentally measured thermal properties of two commonly used phantom materials, i.e. a rigid material with the electrical properties of human fat, and a low concentration polymer gel with the electrical properties of human muscle. Particularities of the two samples required the design of alternative measuring techniques for the specific heat and thermal conductivity. For the specific heat, a calorimeter method is used. For the thermal diffusivity, a method derived from the standard guarded comparative-longitudinal heat flow technique was used for both materials. For the 'muscle'-like material, the thermal conductivity, density and specific heat at constant pressure were measured as: k = 0.31 +/- 0.001 W(mK)(-1), p = 1026 +/- 7 kgm(-3), and c(p) = 4584 +/- 107 J(kgK)(-1). For the 'fat'-like material, the literature reports on the density and specific heat such that only the thermal conductivity was measured as k = 0.55 W(mK)(-1).

  17. Correlation of Polymerization Conditions with Thermal and Mechanical Properties of Polyethylenes Made with Ziegler-Natta Catalysts

    Directory of Open Access Journals (Sweden)

    M. Anwar Parvez

    2014-01-01

    Full Text Available In this study, the synthesis of polyethylenes has been carried out with titanium-magnesium supported Ziegler-Natta catalysts in laboratory-scale reactors. A correlation of different polymerization conditions with thermal and mechanical properties of polyethylenes has been established. It is seen that there is lowering of molecular weight (Mw, polymer yield, and catalyst activity at high hydrogen pressure and high temperature. The Mw, polymer yield, and catalyst activity are improved with the increase in ethylene pressure. Dynamic mechanical analysis (DMA results show that the increase in temperature and hydrogen pressure decreases storage modulus. The samples with higher Mw showed high activation energy. The melting point decreases with the increase in hydrogen pressure but increases slightly with the increase in ethylene pressure. It is seen that the increase in reaction temperature, ethylene pressure, and hydrogen pressure leads to an increase in crystallinity. The tensile modulus increases with the increase in hydrogen pressure and can be correlated with the crystallinity of polymer. The Mw has a major influence on the flow activation energy and tensile strength. But the other mechanical and thermal properties depend on Mw as well as other parameters.

  18. Thermal properties of black phosphorene and doped phosphorene (C, N & O): A DFT study

    Science.gov (United States)

    Devi, Anjna; Singh, Amarjeet

    2018-04-01

    In this work, we present the results from a DFT based computational study of pristine phosphorene and doped (C, N & O) phosphorene. We systematically investigated the lattice thermal properties of black phosphorene and the effect of doping on its thermal properties. We first determined the vibrational properties of pristine and doped phosphorene and from these results we calculated their thermal properties. We doped the phosphorene with C, N and O and observed that the structural stability of doped phosphorene decreases, while the thermal stability is increased as compared to pristine phosphorene. The presence of finite temperature effects in the doped system can contribute to acceleration of progress in future nano-scale technology.

  19. Carbon filter property detection with thermal neutron technique

    International Nuclear Information System (INIS)

    Deng Zhongbo; Han Jun; Li Wenjie

    2003-01-01

    The paper discussed the mechanism that the antigas property of the carbon filter will decrease because of its carbon bed absorbing water from the air while the carbon filter is being stored, and introduced the principle and method of detection the amount of water absorption with thermal neutron technique. Because some certain relation between the antigas property of the carbon filter and the amount of water absorption exists, the decrease degree of the carbon filter antigas property can be estimated through the amount of water absorption, offering a practicable facility technical pathway to quickly non-destructively detect the carbon filter antigas property

  20. Microstructural evolution and mechanical properties of Inconel 718 after thermal exposure

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Z.S., E-mail: yuzaisong@tpri.com.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, No. 28, Xianning West Road, Xi’an 710049 (China); Xi' an Thermal Power Research Institute Co. Ltd., No. 136, Xingqing Road, Xi’an 710032 (China); Zhang, J.X. [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, No. 28, Xianning West Road, Xi’an 710049 (China); Yuan, Y.; Zhou, R.C.; Zhang, H.J.; Wang, H.Z. [Xi' an Thermal Power Research Institute Co. Ltd., No. 136, Xingqing Road, Xi’an 710032 (China)

    2015-05-14

    Inconel 718 was subjected to various heat treatments, i.e., solution heat treatment, standard ageing treatment and standard ageing plus 700 °C thermal exposure. The mechanical properties of the alloys were determined using tensile tests and Charpy pendulum impact tests at 650 °C and room temperature, respectively. The highest yield strength of 988 MPa was attained in the standard aged specimen, whereas a maximum impact toughness of 217 J cm{sup −2} was attained in the solution-treated specimen. After thermal exposure, the mechanical properties of the specimens degrade. Both the yield strength and impact toughness decreased monotonically with increasing thermal exposure time. Subjected to a 10000-h long-term thermal exposure, the yield strength dramatically decreased to 475 MPa (almost 50% of the maximum strength), and the impact toughness reduced to only 18 J cm{sup −2}. The microstructures of the specimens were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Coarsening of γ′ and γ″ and the transformation of γ″ to δ-Ni{sub 3}Nb was observed after thermal exposure. However, a complete transformation from metastable γ″ to δ-Ni{sub 3}Nb was never accomplished, even after the 10000-h long-term thermal exposure. Based on the obtained experimental results, the effects of the microstructural evolution on the mechanical properties are discussed.

  1. Phase Behavior, Thermal Stability and Rheological Properties of PPEK/PC Blends

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Phase behavior, thermal stability and rheological properties of the blends of poly(phthalazinone ether ketone) (PPEK)with bisphenol-A polycarbonate (PC) prepared by solution coprecipitation were studied using differential scanning calorimetry (DSC), Frourier-Transform IR spectroscopy (FT-IR), thermogravimetric analysis (TGA) and capillary rheometer. The DSC results indicated that PPEK/PC blends are almost immiscible in full compositions. FT-IR investigation showed that there were no apparent specific interactions between the constituent polymers. The blends keep excellent thermal stability and the addition of PC degrades the thermal stability of blends to some degree. The thermal degradation processes of the blends are much similar to that of PC. The studies on rheological properties of blends show that blending PPEK with PC is beneficial to reducing the melt viscosity and improving the appearance of PPEK.

  2. Mechanical properties and thermal behaviour of LLDPE/MWNTs nanocomposites

    Directory of Open Access Journals (Sweden)

    Tai Jin-hua

    2012-12-01

    Full Text Available Multi-walled carbon nanotubes (MWNTs were incorporated into a linear low-density polyethylene (LLDPE matrix through using screw extrusion and injection technique. The effect of different weight percent loadings of MWNTs on the morphology, mechanical, and thermal of LLDPE/MWNTs nanocomposite had been investigated. It was found that, at low concentration of MWNTs, it could uniformly disperse into a linear low-density polyethylene matrix and provide LLDPE/MWNTs nanocomposites much improved mechanical properties. Thermal analysis showed that a clear improvement of thermal stability for LLDPE/MWNTs nanocomposites increased with increasing MWNTs content.

  3. Thermal properties. Site descriptive modelling Forsmark - stage 2.2

    International Nuclear Information System (INIS)

    Back, Paer-Erik; Wrafter, John; Sundberg, Jan; Rosen, L ars

    2007-09-01

    The lithological data acquired from boreholes and mapping of the rock surface need to be reclassified into thermal rock classes, TRCs. The main reason is to simplify the simulations. The lithological data are used to construct models of the transition between different TRCs, thus describing the spatial statistical structure of each TRC. The result is a set of transition probability models that are used in the simulation of TRCs. The intermediate result of this first stochastic simulation is a number of realisations of the geology, each one equally probable. Based on the thermal data, a spatial statistical thermal model is constructed for each TRC. It consists of a statistical distribution and a variogram for each TRC. These are used in the stochastic simulation of thermal conductivity and the result is a number of equally probable realisations of thermal conductivity for the domain. In the next step, the realisations of TRCs (lithology) and thermal conductivity are merged, i.e. each realisation of geology is filled with simulated thermal conductivity values. The result is a set of realisations of thermal conductivity that considers both the difference in thermal properties between different TRCs, and the variability within each TRC. If the result is desired in a scale different from the simulation scale, i.e. the canister scale, upscaling of the realisations can be performed. The result is a set of equally probable realisations of thermal properties. The presented methodology was applied to rock domain RFM029 and RFM045. The main results are sets of realisations of thermal properties that can be used for further processing, most importantly for statistical analysis and numerical temperature simulations for the design of repository layout (distances between deposition holes). The main conclusions of the thermal modelling are: The choice of scale has a profound influence on the distribution of thermal conductivity values. The variance decreases and the lower tail

  4. Thermal properties. Site descriptive modelling Forsmark - stage 2.2

    Energy Technology Data Exchange (ETDEWEB)

    Back, Paer-Erik; Wrafter, John; Sundberg, Jan [Geo Innova AB (Sweden); Rosen, L ars [Sweco Viak AB (Sweden)

    2007-09-15

    The lithological data acquired from boreholes and mapping of the rock surface need to be reclassified into thermal rock classes, TRCs. The main reason is to simplify the simulations. The lithological data are used to construct models of the transition between different TRCs, thus describing the spatial statistical structure of each TRC. The result is a set of transition probability models that are used in the simulation of TRCs. The intermediate result of this first stochastic simulation is a number of realisations of the geology, each one equally probable. Based on the thermal data, a spatial statistical thermal model is constructed for each TRC. It consists of a statistical distribution and a variogram for each TRC. These are used in the stochastic simulation of thermal conductivity and the result is a number of equally probable realisations of thermal conductivity for the domain. In the next step, the realisations of TRCs (lithology) and thermal conductivity are merged, i.e. each realisation of geology is filled with simulated thermal conductivity values. The result is a set of realisations of thermal conductivity that considers both the difference in thermal properties between different TRCs, and the variability within each TRC. If the result is desired in a scale different from the simulation scale, i.e. the canister scale, upscaling of the realisations can be performed. The result is a set of equally probable realisations of thermal properties. The presented methodology was applied to rock domain RFM029 and RFM045. The main results are sets of realisations of thermal properties that can be used for further processing, most importantly for statistical analysis and numerical temperature simulations for the design of repository layout (distances between deposition holes). The main conclusions of the thermal modelling are: The choice of scale has a profound influence on the distribution of thermal conductivity values. The variance decreases and the lower tail

  5. Preparation, thermal properties and thermal reliabilities of microencapsulated n-octadecane with acrylic-based polymer shells for thermal energy storage

    International Nuclear Information System (INIS)

    Qiu, Xiaolin; Song, Guolin; Chu, Xiaodong; Li, Xuezhu; Tang, Guoyi

    2013-01-01

    Highlights: ► n-Octadecane was encapsulated by p(butyl methacrylate) (PBMA) and p(butyl acrylate). ► Microcapsules using divinylbenzene as crosslinking agent have better quality. ► Microcapsule with butyl methacrylate–divinylbenzene has highest latent heat. ► Microcapsule with butyl methacrylate–divinylbenzene has greatest thermal stability. ► Phase change temperatures and enthalpies of the microcapsules varied little after thermal cycle. - Abstract: Microencapsulation of n-octadecane with crosslinked p(butyl methacrylate) (PBMA) and p(butyl acrylate) (PBA) as shells for thermal energy storage was carried out by a suspension-like polymerization. Divinylbenzene (DVB) and pentaerythritol triacrylate (PETA) were employed as crosslinking agents. The surface morphologies of the microencapsulated phase change materials (microPCMs) were studied by scanning electron microscopy (SEM). Thermal properties, thermal reliabilities and thermal stabilities of the as-prepared microPCMs were investigated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The microPCMs prepared by using DVB exhibit greater heat capacities and higher thermal stabilities compared with those prepared by using PETA. The thermal resistant temperature of the microPCM with BMA–DVB polymer was up to 248 °C. The phase change temperatures and latent heats of all the as-prepared microcapsules varied little after 1000 thermal cycles.

  6. Thermal properties of an erythritol derivative

    Science.gov (United States)

    Trhlikova, Lucie; Prikryl, Radek; Zmeskal, Oldrich

    2016-06-01

    Erythritol (C4H10O4) is a sugar alcohol (or polyol) that is commonly used in the food industry. Its molar mass is 122.12 g.mol-1 and mass density 1450 kg.m-3. Erythritol, an odorless crystalline powder, can also be characterized by other physical parameters like melting temperature (121 °C) and boiling temperature (329 °C). The substance can be used for the accumulation of energy in heat exchangers based on various oils or water. The PlusICE A118 product manufactured by the PCM Products Ltd. company (melting temperature Θ = 118 °C, specific heat capacity cp = 2.70 kJ.K-1.kg-1, mass density 1450 kg.m-3, latent heat capacity 340 kJ.kg-1, volumetric heat capacity 493 MJ.m-3) is based on an erythritol-type medium. Thermal properties of the PlusICE A118 product in both solid and liquid phase were investigated for this purpose in terms of potential applications. Temperature dependences of its thermal parameters (thermal diffusivity, thermal conductivity, and specific heat) were determined using a transient (step-wise) method. A fractal model of heat transport was used for determination of the above thermal parameters. This model is independent of geometry and type of sample heating. Moreover, it also considers heat losses. The experiment confirmed the formerly declared value of phase change temperature, about 120 °C.

  7. Thermal Properties of Methyl Ester-Containing Poly(2-oxazolines

    Directory of Open Access Journals (Sweden)

    Petra J. M. Bouten

    2015-10-01

    Full Text Available This paper describes the synthesis and thermal properties in solution and bulk of poly(2-alkyl-oxazolines (PAOx containing a methyl ester side chain. Homopolymers of 2-methoxycarbonylethyl-2-oxazoline (MestOx and 2-methoxycarbonylpropyl-2-oxazoline (C3MestOx, as well as copolymers with 2-ethyl-2-oxazoline (EtOx and 2-n-propyl-2-oxazoline (nPropOx, with systematic variations in composition were prepared. The investigation of the solution properties of these polymers revealed that the cloud point temperatures (TCPs could be tuned in between 24 °C and 108 °C by variation of the PAOx composition. To the best of our knowledge, the TCPs of PMestOx and PC3MestOx are reported for the first time and they closely resemble the TCPs of PEtOx and PnPropOx, respectively, indicating similar hydrophilicity of the methyl ester and alkyl side chains. Furthermore, the thermal transitions and thermal stability of these polymers were investigated by DSC and TGA measurements, respectively, revealing amorphous polymers with glass transition temperatures between -1 °C and 54 °C that are thermally stable up to >300 °C.

  8. Preparation and properties of mesoporous silica/bismaleimide/diallylbisphenol composites with improved thermal stability, mechanical and dielectric properties

    Directory of Open Access Journals (Sweden)

    2011-06-01

    Full Text Available New composites with improved thermal stability, mechanical and dielectric properties were developed, which consist of 2,2'-diallylbisphenol A (DBA/4,4'-bismaleimidodiphenylmethane (BDM resin and a new kind of organic/inorganic mesoporous silica (MPSA. Typical properties (curing behavior and mechanism, thermal stability, mechanical and dielectric properties of the composites were systematically investigated, and their origins were discussed. Results show that MPSA/DBA/BDM composites have similar curing temperature as DBA/BDM resin does; however, they have different curing mechanisms, and thus different crosslinked networks. The content of MPSA has close relation with the integrated performance of cured composites. Compared with cured DBA/BDM resin, composites with suitable content of MPSA show obviously improved flexural strength and modulus as well as impact strength; in addition, all composites not only have lower dielectric constant and similar frequency dependence, more interestingly, they also exhibit better stability of frequency on dielectric loss. For thermal stability, the addition of MPSA to DBA/BDM resin significantly decreases the coefficient of thermal expansion, and improves the char yield at high temperature with a slightly reduced glass transition temperature. All these differences in macro-properties are attributed to the different crosslinked networks between MPSA/DBA/BDM composites and DBA/BDM resin.

  9. Preparation and thermal properties of form stable paraffin phase change material encapsulation

    International Nuclear Information System (INIS)

    Liu Xing; Liu Hongyan; Wang Shujun; Zhang Lu; Cheng Hua

    2006-01-01

    Paraffin waxes are cheap and have moderate thermal energy storage density but low thermal conductivity and, hence, require large surface area to be used in energy storage. Form stable paraffin phase change materials (PCM) in which paraffin serves as a latent heat storage material and polyolefins act as a supporting material, because of paraffin leakage, are required to be improved. The form stable paraffin PCM in the present paper was encapsulated in an inorganic silica gel polymer successfully by in situ polymerization. The differential scanning calorimeter (DSC) was used to measure its thermal properties. At the same time, the Washburn equation, which measures the wetting properties of powder materials, was used to test the hydrophilic-lipophilic properties of the PCMs. The result indicated that the enthalpy of the microencapsulated PCMs was reduced little, while their hydrophilic properties were enhanced largely

  10. Validation of a laboratory method for evaluating dynamic properties of reconstructed equine racetrack surfaces.

    Directory of Open Access Journals (Sweden)

    Jacob J Setterbo

    Full Text Available Racetrack surface is a risk factor for racehorse injuries and fatalities. Current research indicates that race surface mechanical properties may be influenced by material composition, moisture content, temperature, and maintenance. Race surface mechanical testing in a controlled laboratory setting would allow for objective evaluation of dynamic properties of surface and factors that affect surface behavior.To develop a method for reconstruction of race surfaces in the laboratory and validate the method by comparison with racetrack measurements of dynamic surface properties.Track-testing device (TTD impact tests were conducted to simulate equine hoof impact on dirt and synthetic race surfaces; tests were performed both in situ (racetrack and using laboratory reconstructions of harvested surface materials. Clegg Hammer in situ measurements were used to guide surface reconstruction in the laboratory. Dynamic surface properties were compared between in situ and laboratory settings. Relationships between racetrack TTD and Clegg Hammer measurements were analyzed using stepwise multiple linear regression.Most dynamic surface property setting differences (racetrack-laboratory were small relative to surface material type differences (dirt-synthetic. Clegg Hammer measurements were more strongly correlated with TTD measurements on the synthetic surface than the dirt surface. On the dirt surface, Clegg Hammer decelerations were negatively correlated with TTD forces.Laboratory reconstruction of racetrack surfaces guided by Clegg Hammer measurements yielded TTD impact measurements similar to in situ values. The negative correlation between TTD and Clegg Hammer measurements confirms the importance of instrument mass when drawing conclusions from testing results. Lighter impact devices may be less appropriate for assessing dynamic surface properties compared to testing equipment designed to simulate hoof impact (TTD.Dynamic impact properties of race surfaces

  11. Measuring technique of super high temperature thermal properties of reactor core materials

    International Nuclear Information System (INIS)

    Ono, Akira; Baba, Tetsuya; Watanabe, Hideo; Matsumoto, Tsuyoshi

    1998-01-01

    In this study, thermal properties of reactor core materials used for water cooled reactors and FBR were tried to develop a technique to measure their melt states at less than 3,000degC in order to contribute more correct evaluation of the reactor core behavior at severe accident. Then, a thermal property measuring method of high temperature melt by using floating method was investigated and its fundamental design was begun to investigate under a base of optimum judgement on the air flow floating throw-down method. And, in order to measure emissivity of melt specimen surface essential for correct temperature measurement using the throw down method, a spectroscopic emissivity measuring unit using an ellipsometer was prepared and induced. On the thermal properties measurement using the holding method, a specimen container to measure thermal diffusiveness of the high temperature melts by using laser flashing method was tried to prepare. (G.K.)

  12. Quantifying the Influence of Near-Surface Water-Energy Budgets on Soil Thermal Properties Using a Network of Coupled Meteorological and Vadose Zone Instrument Arrays in Indiana, USA

    Science.gov (United States)

    Naylor, S.; Gustin, A. R.; Ellett, K. M.

    2012-12-01

    Weather stations that collect reliable, sustained meteorological data sets are becoming more widely distributed because of advances in both instrumentation and data server technology. However, sites collecting soil moisture and soil temperature data remain sparse with even fewer locations where complete meteorological data are collected in conjunction with soil data. Thanks to the advent of sensors that collect continuous in-situ thermal properties data for soils, we have gone a step further and incorporated thermal properties measurements as part of hydrologic instrument arrays in central and northern Indiana. The coupled approach provides insights into the variability of soil thermal conductivity and diffusivity attributable to geologic and climatological controls for various hydrogeologic settings. These data are collected to facilitate the optimization of ground-source heat pumps (GSHPs) in the glaciated Midwest by establishing publicly available data that can be used to parameterize system design models. A network of six monitoring sites was developed in Indiana. Sensors that determine thermal conductivity and diffusivity using radial differential temperature measurements around a heating wire were installed at 1.2 meters below ground surface— a typical depth for horizontal GSHP systems. Each site also includes standard meteorological sensors for calculating reference evapotranspiration following the methods by the Food and Agriculture Organization (FAO) of the United Nations. Vadose zone instrumentation includes time domain reflectometry soil-moisture and temperature sensors installed at 0.3-meter depth intervals down to a 1.8-meter depth, in addition to matric potential sensors at 0.15, 0.3, 0.6, and 1.2 meters. Cores collected at 0.3-meter intervals were analyzed in a laboratory for grain size distribution, bulk density, thermal conductivity, and thermal diffusivity. Our work includes developing methods for calibrating thermal properties sensors based on

  13. Correlation of physical properties of ceramic materials with resistance to fracture by thermal shock

    Science.gov (United States)

    Lidman, W G; Bobrowsky, A R

    1949-01-01

    An analysis is made to determine which properties of materials affect their resistance to fracture by thermal stresses.From this analysis, a parameter is evaluated that is correlated with the resistance of ceramic materials to fracture by thermal shock as experimentally determined. This parameter may be used to predict qualitatively the resistance of a material to fracture by thermal shock. Resistance to fracture by thermal shock is shown to be dependent upon the following material properties: thermal conductivity, tensile strength, thermal expansion, and ductility modulus. For qualitative prediction of resistance of materials to fracture by thermal shock, the parameter may be expressed as the product of thermal conductivity and tensile strength divided by the product of linear coefficient of thermal expansion and ductility modulus of the specimen.

  14. ''Glassy'' low temperature thermal properties in crystalline solids

    International Nuclear Information System (INIS)

    Nathan, B.D.

    1976-05-01

    Amorphous dielectrics are known to exhibit anomalous low temperature properties. An extensive review of these properties is presented with an eye toward an understanding of low-lying excitation modes thought to exist in glasses. Work on these systems is described in which a Zr-20 percent Nb samplewhich would be expected to reduce and redistribute the proposed tunneling states. Indeed, the thermal conductivity becomes similar to that of a quenched Zr-8 percent Nb sample and the ''excess'' specific heat linear in temperature dependence is reduced to half the value found in quenched Zr-20 percent Nb. The coefficient of the T 3 term in the specific heat unexpectedly increased from 23.3 to 56.9 erg/gm K 4 and this is attributed to a softening of the lattice due to annealing. The specific heat of this sample was remeasured after it had been dunked in liquid nitrogen. The cubic term was then found to be 19.5 erg/g K 4 , smaller than that in quenched Zr-20 percent Nb, an effect which had been expected due to the chemical diffusion during annealing. Further study of this phenomenon is suggested. Among other relevant measurements performed were the specific heat of a sample of amorphous B 2 O 3 (presented by Stephens (1976)); thermal conductivities of phase-separated unleached Vycor glass and Pyrex; thermal conductivities above 1.2 0 K of polycrystalline MgO, heat-treated Pyroceram and porous Vycor (presented by Tait (1975)) and of mixed crystal KBr-KI (presented by Nathan, Lou and Tait (1976)). The last sample exhibited density fluctuations on a scale of 1000 A but exhibited thermal properties typical of dielectric crystal. Speed of sound measurements were made on both unleached and porous Vycor

  15. Influence of Thermal Treatment Conditions on the Properties of Dental Silicate Cements

    Directory of Open Access Journals (Sweden)

    Georgeta Voicu

    2016-02-01

    Full Text Available In this study the sol-gel process was used to synthesize a precursor mixture for the preparation of silicate cement, also called mineral trioxide aggregate (MTA cement. This mixture was thermally treated under two different conditions (1400 °C/2 h and 1450 °C/3 h followed by rapid cooling in air. The resulted material (clinker was ground for one hour in a laboratory planetary mill (v = 150 rot/min, in order to obtain the MTA cements. The setting time and mechanical properties, in vitro induction of apatite formation by soaking in simulated body fluid (SBF and cytocompatibility of the MTA cements were assessed in this study. The hardening processes, nature of the reaction products and the microstructural characteristics were also investigated. The anhydrous and hydrated cements were characterized by different techniques e.g., X-ray diffraction (XRD, scanning electron microscopy (SEM, infrared spectroscopy (FT-IR and thermal analysis (DTA-DTG-TG. The setting time of the MTA cement obtained by thermal treatment at 1400 °C/2 h (MTA1 was 55 min and 15 min for the MTA cement obtained at 1450 °C/3 h (MTA2. The compressive strength values were 18.5 MPa (MTA1 and 22.9 MPa (MTA2. Both MTA cements showed good bioactivity (assessed by an in vitro test, good cytocompatibility and stimulatory effect on the proliferation of cells.

  16. The thermal properties of beeswaxes: unexpected findings.

    Science.gov (United States)

    Buchwald, Robert; Breed, Michael D; Greenberg, Alan R

    2008-01-01

    Standard melting point analyses only partially describe the thermal properties of eusocial beeswaxes. Differential scanning calorimetry (DSC) revealed that thermal phase changes in wax are initiated at substantially lower temperatures than visually observed melting points. Instead of a sharp, single endothermic peak at the published melting point of 64 degrees C, DSC analysis of Apis mellifera Linnaeus wax yielded a broad melting curve that showed the initiation of melting at approximately 40 degrees C. Although Apis beeswax retained a solid appearance at these temperatures, heat absorption and initiation of melting could affect the structural characteristics of the wax. Additionally, a more complete characterization of the thermal properties indicated that the onset of melting, melting range and heat of fusion of beeswaxes varied significantly among tribes of social bees (Bombini, Meliponini, Apini). Compared with other waxes examined, the relatively malleable wax of bumblebees (Bombini) had the lowest onset of melting and lowest heat of fusion but an intermediate melting temperature range. Stingless bee (Meliponini) wax was intermediate between bumblebee and honeybee wax (Apini) in heat of fusion, but had the highest onset of melting and the narrowest melting temperature range. The broad melting temperature range and high heat of fusion in the Apini may be associated with the use of wax comb as a free-hanging structural material, while the Bombini and Meliponini support their wax structures with exogenous materials.

  17. Thermal Properties of Anionic Polyurethane Composition for Leather Finishing

    Directory of Open Access Journals (Sweden)

    Olga KOVTUNENKO

    2016-09-01

    Full Text Available Thermal properties of anionic polyurethane composition mixed with collagen product and hydrophilic sodium form of montmorillonite for use in the finishing of leather were studied by thermogravimetric method. The thermal indices of processes of thermal and thermo-oxidative destruction depending on the polyurethane composition were determined. The influence of anionic polyurethane composition on thermal behavior of chromium tanned gelatin films that imitate the leather were studied. APU composition with natural compounds increases their thermal stability both in air and in nitrogen atmosphere due to the formation of additional bonds between active groups of APU, protein and chrome tanning agent as the result of chemical reactions between organic and inorganic parts with the new structure formation.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.10043

  18. Dynamic properties of a metal photo-thermal micro-actuator.

    Science.gov (United States)

    Shi, B; Zhang, H J; Wang, B; Yi, F T; Jiang, J Z; Zhang, D X

    2015-02-20

    This work presents the design, modeling, simulation, and characterization of a metal bent-beam photo-thermal micro-actuator. The mechanism of actuation is based on the thermal expansion of the micro-actuator which is irradiated by a laser, achieving noncontact control of the power supply. Models for micro-actuators were established and finite-element simulations were carried out to investigate the effects of various parameters on actuation properties. It is found that the thermal expansion coefficient, thermal conductivity, and the geometry size largely affected actuation behavior whereas heat capacity, density, and Young's modulus did not. Experiments demonstrated the dynamic properties of a Ni micro-actuator fabricated via LIGA technology with 1100/30/100 μm (long/wide/thick) arms. The tip displacement of the micro-actuator could achieve up to 42 μm driven by a laser beam (1064 nm wavelength, 1.2 W power, and a driving frequency of 1 HZ). It is found that the tip displacement decreases with increasing laser driving frequency. For 8 Hz driving frequency, 17 μm (peak-valley value) can be still reached, which is large enough for the application as micro-electro-mechanical systems. Metal photo-thermal micro actuators have advantages such as large displacement, simple structure, and large temperature tolerance, and therefore they will be promising in the fields of micro/nanotechnology.

  19. Preliminary analysis of the potential for thermally-induced rock fracture around high-level waste containers

    International Nuclear Information System (INIS)

    Ratigan, J.L.

    1976-01-01

    The major results are: the development of parametric formulations relating the potential for thermally induced fracturing in the high-level radioactive waste repository concept to the elastic and thermal properties of the site rock and the depth of the excavation, and the recognition of a need to determine the actual ''failure envelope'' for any potential site rock in the laboratory and adjust the parametric relations appropriately. Analysis of five rock types indicated that none would experience elastic/brittle failure due to the thermal stresses induced by the introduction of a 5 kW heat source. However, the rock strengths and elastic properties are laboratory values and not in situ values

  20. Densely crosslinked polycarbosiloxanes .2. Thermal and mechanical properties

    NARCIS (Netherlands)

    Flipsen, T.A C; Derks, R.; van der Vegt, H.A.; Stenekes, R.; Pennings, A.J; Hadziioannou, G

    1997-01-01

    The thermal and mechanical properties of two densely crosslinked polycarbosiloxane systems were investigated in relation to the molecular structure. The networks were prepared from functional branched prepolymers and crosslinked via a hydrosilylation curing reaction. The prepolymers having only

  1. Thermal properties of poly(3-hydroxybutyrate)/vegetable fiber composites

    Science.gov (United States)

    Vitorino, Maria B. C.; Reul, Lízzia T. A.; Carvalho, Laura H.; Canedo, Eduardo L.

    2015-05-01

    The present work studies the thermal properties of composites of poly(3-hydroxybutyrate) (PHB) - a fully biodegradable semi-crystalline thermo-plastic obtained from renewable resources through low-impact biotechno-logical process, biocompatible and non-toxic - and vegetable fiber from the fruit (coconut) of babassu palm tree. PHB is a highly crystalline resin and this characteristic leads to suboptimal properties in some cases. Consequently, thermal properties, in particular those associated with the crystallization of the matrix, are important to judge the suitability of the compounds for specific applications. PHB/babassu composites with 0-50% load were prepared in an internal mixer. Two different types of babassu fibers with two different particle size ranges were compounded with PHB and test specimens molded by compression. Melting and crystallization behavior were studied by differential scanning calorimetry (DSC) at heating/cooling rates between 2 and 30°C/min. Several parameters, including melting point, crystallization temperature, crystallinity, and rate of crystallization, were estimated as functions of load and heating/cooling rates. Results indicate that fibers do not affect the melting process, but facilitate crystallization from the melt. Crystallization temperatures are 30 to 40°C higher for the compounds compared with the neat resin. However, the amount of fiber added has little effect on crystallinity and the degree of crystallinity is hardly affected by the load. Fiber type and initial particle size do not have a significant effect on thermal properties.

  2. Study of the thermal properties of selected PCMs for latent heat storage in buildings

    Science.gov (United States)

    Valentova, Katerina; Pechackova, Katerina; Prikryl, Radek; Ostry, Milan; Zmeskal, Oldrich

    2017-07-01

    The paper is focused on measurements of thermal properties of selected phase change materials (PCMs) which can be used for latent heat storage in building structures. The thermal properties were measured by the transient step-wise method and analyzed by the thermal spectroscopy. The results of three different materials (RT18HC, RT28HC, and RT35HC) and their thermal properties in solid, liquid, and phase change region were determined. They were correlated with the differential scanning calorimetry (DSC) measurement. The results will be used to determine the optimum ratio of components for the construction of drywall and plasters containing listed ingredients, respectively.

  3. Effect of thermal processing practices on the properties of superplastic Al-Li alloys

    Science.gov (United States)

    Hales, Stephen J.; Lippard, Henry E.

    1993-01-01

    The effect of thermal processing on the mechanical properties of superplastically formed structural components fabricated from three aluminum-lithium alloys was evaluated. The starting materials consisted of 8090, 2090, and X2095 (Weldalite(TM) 049), in the form of commercial-grade superplastic sheet. The experimental test matrix was designed to assess the impact on mechanical properties of eliminating solution heat treatment and/or cold water quenching from post-forming thermal processing. The extensive hardness and tensile property data compiled are presented as a function of aging temperature, superplastic strain and temper/quench rate for each alloy. The tensile properties of the materials following superplastic forming in two T5-type tempers are compared with the baseline T6 temper. The implications for simplifying thermal processing without degradation in properties are discussed on the basis of the results.

  4. Physicochemical, rheological, thermal, and bread making properties of flour obtained from irradiated wheat

    International Nuclear Information System (INIS)

    Singer, Carolina Sobral

    2006-01-01

    Most of the methods that are nowadays used for food preservation derive from old times. Besides these methods, new non-thermal methods have been developed in order to improve food quality during its processing. Irradiation technology has a great contribution potential to improve preservation, storage and distribution of foods. Several studies from international literature have reported the efficiency of irradiation process on microbiological control of grains and their products. Due to the low technological quality of national wheat, Brazil depends on its import. Wheat is the main ingredient of bread which is one of the most important products of Brazilian people's diet. The objective of this work was to study the effect of ionizing radiation on wheat on physicochemical, rheological, and thermal properties of flour produced from this wheat, and consequently, its performance on bread making. All experiments were conducted on laboratory scale. Wheat was submitted to irradiation on different doses (0.0; 0.5; 1.0 and 2.0 kGy) and flour produced underwent physicochemical, rheological, thermal and microbiological analyses. Flour bread making performance was measured through quality of bread. None of the physicochemical, rheological or thermal parameters was influenced by irradiation, with the exception of Falling Number, which decreased significantly with the increase of irradiation dose, indicating the effect of irradiation on wheat starch, and consequently on dough's gelatinization. Bread quality parameters did also not show significant differences, and sensory analysis showed that bread produced from irradiated and non irradiated wheat did not present perceivable flavor. (author)

  5. CaTs Lab (CHAOS and Thermal Sciences Laboratory)

    Science.gov (United States)

    Teate, Anthony A.

    2002-01-01

    The CHAOS and Thermal Sciences Laboratory (CaTs) at James Madison University evolved into a noteworthy effort to increase minority representation in the sciences and mathematics. Serving ten students and faculty directly, and nearly 50 students indirectly, CaTs, through recruitment efforts, workshops, mentoring programs, tutorial services and research and computational laboratories, fulfilled its intent to initiate an academically enriched research program aimed at strengthening the academic and self-actualization skills of undergraduate students with potential to pursue doctoral study in the sciences. The stated goal of the program was to increase by 5% the number of enrolled mathematics and science students into the program. Success far exceeded the program goals by producing 100% graduation rate of all supported recipients during its tenure, with 30% of the students subsequently in pursuit of graduate degrees. Student retention in the program exceeded 90% and faculty participation exceeded the three members involved in mentoring and tutoring, gaining multi-disciplinary support. Aggressive marketing of the program resulted in several paid summer internships and commitments from NASA and an ongoing relationship with CHROME, a nationally recognized organization which focuses on developing minority students in the sciences and mathematics. Success of the program was only limited by the limited fiscal resources at NASA which resulted in phasing out of the program.

  6. Moisture dependent thermal properties of hydrophilic mineral wool: application of the effective media theory

    Directory of Open Access Journals (Sweden)

    Iñigo Antepara

    2015-09-01

    Full Text Available Thermal properties of mineral wool based materials appear to be of particular importance for their practical applications because the majority of them is used in the form of thermal insulation boards. Every catalogue list of any material producer of mineral wool contains thermal conductivity, sometimes also specific heat capacity, but they give only single characteristic values for dry state of material mostly. Exposure to outside climate or any other environment containing moisture can negatively affect the thermal insulation properties of mineral wool. Nevertheless, the mineral wool materials due to their climatic loading and their environmental exposure contain moisture that can negatively affect their thermal insulation properties. Because the presence of water in mineral wool material is undesirable for the majority of applications, many products are provided with hydrophobic substances. Hydrophilic additives are seldom used in mineral wool products. However, this kind of materials has a good potential for application for instance in interior thermal insulation systems, masonry desalination, green roofs, etc. For these materials, certain moisture content must be estimated and thus their thermal properties will be different than for the dry state. On this account, moisture dependent thermal properties of hydrophilic mineral wool (HMW are studied in a wide range of moisture content using a pulse technique. The experimentally determined thermal conductivity data is analysed using several homogenization formulas based on the effective media theory. In terms of homogenization, a porous material is considered as a mixture of two or three phases. In case of dry state, material consists from solid and gaseous phase. When moistened, liquid phase is also present. Mineral wool consists of the solid phase represented by basalt fibers, the liquid phase by water and the gaseous phase by air. At first, the homogenization techniques are applied for the

  7. Rare Earth Borohydrides—Crystal Structures and Thermal Properties

    Directory of Open Access Journals (Sweden)

    Christoph Frommen

    2017-12-01

    Full Text Available Rare earth (RE borohydrides have received considerable attention during the past ten years as possible hydrogen storage materials due to their relatively high gravimetric hydrogen density. This review illustrates the rich chemistry, structural diversity and thermal properties of borohydrides containing RE elements. In addition, it highlights the decomposition and rehydrogenation properties of composites containing RE-borohydrides, light-weight metal borohydrides such as LiBH4 and additives such as LiH.

  8. THERMAL AND DIELECTRIC PROPERTIES OF PINE WOOD IN THE TRANSVERSE DIRECTION

    Directory of Open Access Journals (Sweden)

    Hamiyet Şahin Kol

    2009-11-01

    Full Text Available In this paper, the thermal conductivity and dielectric parameters for pine [Pinus sylvestris (L.] woods were determined in transverse directions for moisture conditions from oven-dry to 22 percent at a room temperature of 22 to 24 °C. Results indicate that the behaviors of thermal conductivity and dielectric parameters with moisture content and structural directions were similar. In general, the properties increased within the range studied with increasing moisture content. The radial values were similar to tangential values for both thermal conductivity and dielectric properties. The data presented here should be useful in most design problems where pine wood is subjected to microwave electric fields and heat changes.

  9. A New Method to Determine Thermal Properties of the Mixture of PCM and Concrete

    DEFF Research Database (Denmark)

    R., Cheng; Pomianowski, Michal Zbigniew; Heiselberg, Per

    on the inverse problem was proposed to deal with the measurements of thermal conductivity and specific heat of PCM-concretes during the phase change process. This method transforms the determination process to an optimization problem, which regarded the difference between the measured and calculated heat flux......Integration of phase change materials in building envelopes is a technology that with high potential to decrease the building energy consumption and improve indoor thermal comfort. Accurate measurement of thermal physical properties of PCM-concretes is very important for simulation and evaluation...... of its energy saving performance. However, there isn’t an effective way to measure thermal physical properties of PCM-concretes accurately. The shortcomings of using traditional testing methods to measure thermal physical properties of PCM-concretes were firstly analyzed. Then a new method based...

  10. Thermal properties of self-gravitating plane-symmetric configuration

    Energy Technology Data Exchange (ETDEWEB)

    Hara, T; Ikeuchi, S [Kyoto Univ. (Japan). Dept. of Physics; Sugimoto, D

    1976-09-01

    As a limiting case of rotating stars, thermal properties of infinite plane-symmetric self-gravitating gas are investigated. Such a configuration is characterized by surface density of the plane instead of stellar mass. In the Kelvin contraction, temperature of the interior decreases, if the surface density is kept constant. If the accretion of matter takes place, or if the angular momenta are transferred outward, the surface density will increase. In this case, the temperature of the interior may increase. When a nuclear burning is ignited, it is thermally unstable in most cases, even when electrons are non-degenerate. This thermal instability is one of the essential differences of the plane-symmetric configuration from the spherical star. Such instabilities are computed for different cases of nuclear fuels. This type of nuclear instability is the same phenomenon as thermal instability of a thin shell burning in a spherical star.

  11. Do encapsulated heat storage materials really retain their original thermal properties?

    Science.gov (United States)

    Chaiyasat, Preeyaporn; Noppalit, Sayrung; Okubo, Masayoshi; Chaiyasat, Amorn

    2015-01-14

    The encapsulation of Rubitherm®27 (RT27), which is one of the most common commercially supplied heat storage materials, by polystyrene (PS), polydivinyl benzene (PDVB) and polymethyl methacrylate (PMMA) was carried out using conventional radical microsuspension polymerization. The products were purified to remove free RT27 and free polymer particles without RT27. In the cases of PS and PDVB microcapsules, the latent heats of melting and crystallization for RT27 ( and , J/g-RT27) were clearly decreased by the encapsulation. On the other hand, those of the PMMA microcapsules were the same as pure RT27. A supercooling phenomenon was observed not only for PS and PDVB but also for the PMMA microcapsules. These results indicate that the thermal properties of the heat storage materials encapsulated depend on the type of polymer shells, i.e., encapsulation by polymer shell changes the thermal properties of RT27. This is quite different from the idea of other groups in the world, in which they discussed the thermal properties based on the ΔHm and ΔHc values expressed in J/g-capsule, assuming that the thermal properties of the heat storage materials are not changed by the encapsulation. Hereafter, this report should raise an alarm concerning the "wrong" common knowledge behind developing the encapsulation technology of heat storage materials.

  12. Preparation, thermal properties and thermal reliabilities of microencapsulated n-octadecane with acrylic-based polymer shells for thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Xiaolin [Advanced Materials Institute and Clearer Production Key Laboratory, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Key Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Haidian District, Beijing 100084 (China); Song, Guolin; Chu, Xiaodong; Li, Xuezhu [Advanced Materials Institute and Clearer Production Key Laboratory, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Tang, Guoyi, E-mail: tanggy@tsinghua.edu.cn [Advanced Materials Institute and Clearer Production Key Laboratory, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Key Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Haidian District, Beijing 100084 (China)

    2013-01-10

    Highlights: Black-Right-Pointing-Pointer n-Octadecane was encapsulated by p(butyl methacrylate) (PBMA) and p(butyl acrylate). Black-Right-Pointing-Pointer Microcapsules using divinylbenzene as crosslinking agent have better quality. Black-Right-Pointing-Pointer Microcapsule with butyl methacrylate-divinylbenzene has highest latent heat. Black-Right-Pointing-Pointer Microcapsule with butyl methacrylate-divinylbenzene has greatest thermal stability. Black-Right-Pointing-Pointer Phase change temperatures and enthalpies of the microcapsules varied little after thermal cycle. - Abstract: Microencapsulation of n-octadecane with crosslinked p(butyl methacrylate) (PBMA) and p(butyl acrylate) (PBA) as shells for thermal energy storage was carried out by a suspension-like polymerization. Divinylbenzene (DVB) and pentaerythritol triacrylate (PETA) were employed as crosslinking agents. The surface morphologies of the microencapsulated phase change materials (microPCMs) were studied by scanning electron microscopy (SEM). Thermal properties, thermal reliabilities and thermal stabilities of the as-prepared microPCMs were investigated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The microPCMs prepared by using DVB exhibit greater heat capacities and higher thermal stabilities compared with those prepared by using PETA. The thermal resistant temperature of the microPCM with BMA-DVB polymer was up to 248 Degree-Sign C. The phase change temperatures and latent heats of all the as-prepared microcapsules varied little after 1000 thermal cycles.

  13. Transport and calorimetric properties of AISI 321 by pulse thermal diffusivity and calorimetric techniques

    International Nuclear Information System (INIS)

    Perovic, N.L.; Maglic, K.D.; Stanimirovic, A.M.; Vukovic, G.S.

    1995-01-01

    The study of the thermophysical properties of AISI 321 stainless steel was the last part of work within the IAEA-coordinated Research Programme for the Establishment of a Database of Thermophysical Properties of LW and HW Reactor Materials (IAEA CRP) effected at the Institute of Nuclear Sciences Vinca (NIV). The AISI 321 stainless steel belongs to the group of construction materials whose thermophysical and calorimetric properties have significance for the IAEA CRP. Because there have been few investigations of the thermal properties of this material, the CRP foresaw the need for new measurements, which are reported in this paper. Experimental research performed at NIV consisted of the investigation of thermal diffusivity, electric resistivity, and specific heat capacity of this austenitic stainless steel. The thermal diffusivity was measured by the laser pulse technique, and the elastic resistivity and specific heat capacity were determined by use of millisecond-resolution pulse calorimetry. All measurements were performed from ambient temperature to above 1000 o C, within which temperature range the material maintains its structure and stable thermophysical properties. Values for the thermal conductivity were computed from data on the thermal diffusivity, specific heat capacity, and the room-temperature density. (author)

  14. High Temperature Thermal Properties of Bentonite Foundry Sand

    Directory of Open Access Journals (Sweden)

    Krajewski P.K.

    2015-06-01

    Full Text Available The paper presents results of measuring thermal conductivity and heat capacity of bentonite foundry sand in temperature range ambient - 900­­°C. During the experiments a technical purity Cu plate was cast into the green-sand moulds. Basing on measurements of the mould temperature field during the solidification of the casting, the temperature relationships of the measured properties were evaluated. It was confirmed that water vaporization strongly influences thermal conductivity of the moulding sand in the first period of the mould heating by the poured casting.

  15. Mechanical properties of clayey soils and thermal solicitations

    International Nuclear Information System (INIS)

    Boisson, J.Y.

    1992-01-01

    Changes in permeability and mechanical properties of three clayey soils with temperature have been studied by using a special oedometric cell. The action of a thermal solicitation on the fabric and the behavior of the samples is highlighted. 3 figs., 1 tab

  16. Thermal effects on clay rocks for deep disposal of high-level radioactive waste

    Directory of Open Access Journals (Sweden)

    Chun-Liang Zhang

    2017-06-01

    Full Text Available Thermal effects on the Callovo-Oxfordian and Opalinus clay rocks for hosting high-level radioactive waste were comprehensively investigated with laboratory and in situ experiments under repository relevant conditions: (1 stresses covering the range from the initial lithostatic state to redistributed levels after excavation, (2 hydraulic drained and undrained boundaries, and (3 heating from ambient temperature up to 90 °C–120 °C and a subsequent cooling phase. The laboratory experiments were performed on normal-sized and large hollow cylindrical samples in various respects of thermal expansion and contraction, thermally-induced pore water pressure, temperature influences on deformation and strength, thermal impacts on swelling, fracture sealing and permeability. The laboratory results obtained from the samples are consistent with the in situ observations during heating experiments in the underground research laboratories at Bure and Mont-Terri. Even though the claystones showed significant responses to thermal loading, no negative effects on their favorable barrier properties were observed.

  17. Mechanical and Thermal Properties of the AH of FRW Universe

    International Nuclear Information System (INIS)

    Yi-Huan, Wei

    2010-01-01

    We calculate the work made out by the apparent horizon (AH) of the Friedmann–Robertson–Walker (FRW) universe and the heat flux through the AH from the first law of thermodynamics. We discuss the mechanical properties of the AH and analyze the universe model for which the mechanical properties can change. Finally, the thermal properties of the AH of FRW universe are discussed

  18. Performance of the Opalinus Clay under thermal loading: experimental results from Mont Terri rock laboratory (Switzerland)

    Energy Technology Data Exchange (ETDEWEB)

    Gens, A. [Universitat Politència de Catalunya, Barcelona (Spain); Wieczorek, K. [Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) GmbH, Braunschweig (Germany); Gaus, I. [National Cooperative for the Disposal of Radioactive Waste (NAGRA), Wettingen (Switzerland); and others

    2017-04-15

    The paper presents an overview of the behaviour of Opalinus Clay under thermal loading as observed in three in situ heating tests performed in the Mont Terri rock laboratory: HE-B, HE-D and HE-E. The three tests are summarily described; they encompass a broad range of test layouts and experimental conditions. Afterwards, the following topics are examined: determination of thermal conductivity, thermally-induced pore pressure generation and thermally-induced mechanical effects. The mechanisms underlying pore pressure generation and dissipation are discussed in detail and the relationship between rock damage and thermal loading is examined using an additional in situ test: SE-H. The paper concludes with an evaluation of the various thermo-hydro-mechanical (THM) interactions identified in the heating tests. (authors)

  19. Thermal power sludge – properties, treatment, utilization

    Directory of Open Access Journals (Sweden)

    Martin Sisol

    2005-11-01

    Full Text Available In this paper a knowledge about properties of thermal power sludge from coal combustion in smelting boilers is presented. The physical and technological properties of slag – granularity, density, specific, volume and pouring weight, hardness and decoupling – together with chemical properties influence its exploitation. The possibility of concentrating the Fe component by the mineral processing technologies (wet low-intenzity magnetic separation is verified. An industrial use of the slag in civil engineering, e.g. road construction, was realised. The slag-fly ashes are directly utilized in the cement production as a substitute of a part of natural raw materials. For the use of slag as the stoneware in the road construction, all the criteria are fulfilled.

  20. Biodegradable compounds: Rheological, mechanical and thermal properties

    Science.gov (United States)

    Nobile, Maria Rossella; Lucia, G.; Santella, M.; Malinconico, M.; Cerruti, P.; Pantani, R.

    2015-12-01

    Recently great attention from industry has been focused on biodegradable polyesters derived from renewable resources. In particular, PLA has attracted great interest due to its high strength and high modulus and a good biocompatibility, however its brittleness and low heat distortion temperature (HDT) restrict its wide application. On the other hand, Poly(butylene succinate) (PBS) is a biodegradable polymer with a low tensile modulus but characterized by a high flexibility, excellent impact strength, good thermal and chemical resistance. In this work the two aliphatic biodegradable polyesters PBS and PLA were selected with the aim to obtain a biodegradable material for the industry of plastic cups and plates. PBS was also blended with a thermoplastic starch. Talc was also added to the compounds because of its low cost and its effectiveness in increasing the modulus and the HDT of polymers. The compounds were obtained by melt compounding in a single screw extruder and the rheological, mechanical and thermal properties were investigated. The properties of the two compounds were compared and it was found that the values of the tensile modulus and elongation at break measured for the PBS/PLA/Talc compound make it interesting for the production of disposable plates and cups. In terms of thermal resistance the compounds have HDTs high enough to contain hot food or beverages. The PLA/PBS/Talc compound can be, then, considered as biodegradable substitute for polystyrene for the production of disposable plates and cups for hot food and beverages.

  1. Electrical and thermal properties of graphite/polyaniline composites

    Energy Technology Data Exchange (ETDEWEB)

    Bourdo, Shawn E., E-mail: sxbourdo@ualr.edu [Center for Integrative Nanotechnology Sciences, University of Arkansas at Little Rock, 2801 South University Avenue, Little Rock, AR 72204 (United States); Warford, Brock A.; Viswanathan, Tito [Department of Chemistry, University of Arkansas at Little Rock, 2801 South University Avenue, Little Rock, AR 72204 (United States)

    2012-12-15

    A composite of a carbon allotrope (graphite) and an inherently conducting polymer, polyaniline (PANI), has been prepared that exhibits an electrical conductivity greater than either of the two components. An almost 2-fold increase in the bulk conductivity occurs when only a small mass fraction of polyaniline exists in the composite (91% graphite/ 9% polyaniline, by mass). This increase in dc electrical conductivity is curious since in most cases a composite material will exhibit a conductivity somewhere between the two individual components, unless a modification to the electronic nature of the material occurs. In order to elucidate the fundamental electrical properties of the composite we have performed variable temperature conductivity measurements to better understand the nature of conduction in these materials. The results from these studies suggest a change in the mechanism of conduction as the amount of polyaniline is increased in the composite. Along with superior electrical properties, the composites exhibit an increase in thermal stability as compared to the graphite. - Graphical abstract: (Left) Room temperature electrical conductivity of G-PANI composites at different mass ratios. (Right) Electrical conductivity of G-PANI composites at temperatures from 5 K to 300 K. Highlights: Black-Right-Pointing-Pointer Composites of graphite and polyaniline have been synthesized with unique electrical and thermal properties. Black-Right-Pointing-Pointer Certain G-PANI composites are more conductive and more thermally stable than graphite alone. Black-Right-Pointing-Pointer G-PANI composites exhibit a larger conductivity ratio with respect to temperature than graphite alone.

  2. Preparation, characterization and thermal properties of PMMA/n-heptadecane microcapsules as novel solid-liquid microPCM for thermal energy storage

    International Nuclear Information System (INIS)

    Sari, Ahmet; Alkan, Cemil; Karaipekli, Ali

    2010-01-01

    This study is focused on the preparation, characterization and thermal properties of microencapsulated n-heptadecane with polymethylmethacrylate shell. The PMMA/heptadecane microcapsules were synthesized as novel solid-liquid microencapsulated phase change material (microPCMs) by emulsion polymerization method. The chemical and thermal characterization of the microPCMs were investigated using scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). The diameters of microPCMs were found in the narrow range (0.14-0.40 μm) under the stirring speed of 2000 rpm. The spherical surfaces of microPCMs were smooth and compact. The DSC results show that microPCMs have good energy storage capacity. Thermal cycling test showed that the microPCMs have good thermal reliability with respect to the changes in their thermal properties after repeated 5000 thermal cycling. TGA analyses also indicated that the microPCMs degraded in three steps and have good thermal stability. Based on all results, it can be considered that the PMMA/heptadecane microcapsules as novel solid-liquid microPCMs have good energy storage potential.

  3. Determination of thermal conductivity in foundry mould mixtures

    Directory of Open Access Journals (Sweden)

    G. Solenički

    2010-01-01

    Full Text Available For a thorough understanding of the behaviour of foundry mould mixtures, a good knowledge of thermal properties of mould materials is needed. Laboratory determination of thermal conductivity of mould mixtures enables a better control over scabbing defects which are a major problem in green sand mould mixtures. A special instrument has been designed for that purpose and it is described in this work.

  4. Application of Glass Fiber Waste Polypropylene Aggregate in Lightweight Concrete – thermal properties

    Science.gov (United States)

    Citek, D.; Rehacek, S.; Pavlik, Z.; Kolisko, J.; Dobias, D.; Pavlikova, M.

    2018-03-01

    Actual paper focus on thermal properties of a sustainable lightweight concrete incorporating high volume of waste polypropylene aggregate as partial substitution of natural aggregate. In presented experiments a glass fiber reinforced polypropylene (GFPP) which is a by-product of PP tubes production, partially substituted fine natural silica aggregate in 10, 20, 30, 40 and 50 mass %. Results were compared with a reference concrete mix without plastic waste in order to quantify the effect of GFPP use on concrete properties. Main material physical parameters were studied (bulk density, matrix density without air content, and particle size distribution). Especially a thermal transport and storage properties of GFPP were examined in dependence on compaction time. For the developed lightweight concrete, thermal properties were accessed using transient impulse technique, where the measurement was done in dependence on moisture content (from the fully water saturated state to dry state). It was found that the tested lightweight concrete should be prospective construction material possessing improved thermal insulation function and the reuse of waste plastics in concrete composition was beneficial both from the environmental and financial point of view.

  5. Geothermal properties of Swiss Molasse Basin (depth range 0-500 m) - 2006 upgrade of the thermal conductivity, heat capacity, rock density and porosity data base

    International Nuclear Information System (INIS)

    Leu, W.; Megel, T.; Schaerli, U.

    2006-01-01

    The main aim of this project is the preparation of a specific data base of geothermal properties for typical rocks of the Swiss Molasse Basin (depth interval 0-500 m). The project includes the development of a new laboratory tool for efficient heat capacity measurements on rock samples, numerous new measurements of geothermal rock properties in the laboratory and calculation of such data from geophysical borehole logs. In the geographical area under review, 282 rock samples, mainly from deep boreholes, were analyzed with the successfully calibrated new heat capacity device and conventional thermal conductivity measuring techniques (cuttings and cores). Based on sonic and density log data from exploration wells, 374 additional data points were generated. This new data base characterizes in detail the six main lithological rock types in the three Molasse groups OSM, OMM and USM within the Swiss Plateau Molasse. The statistical evaluation of all data illustrates the regional variation of the petrophysical and geothermal parameters. For most data groups bulk rock density and thermal conductivity increase, whereas heat capacity decreases in the direction towards the Alpine front. Thermal conductivity shows a distinct increase with depth. Based on this new information and with the aid of the evaluation software tool SwEWS, the costs of planned geothermal installations can be optimized thanks to more precise heat extraction simulations with existing software packages like COSOND, TRNSYS, EWS or WPcalc. (author)

  6. Effect of magnetic and thermal properties of iron oxide nanoparticles (IONs) in nitrile butadiene rubber (NBR) latex

    International Nuclear Information System (INIS)

    Ong, Hun Tiar; Julkapli, Nurhidayatullaili Muhd; Hamid, Sharifah Bee Abd; Boondamnoen, O.; Tai, Mun Foong

    2015-01-01

    Nitrile butadiene rubber (NBR) gloves are one of the most important personal protective equipments but they are possible to tear off and contaminate food or pharmaceutical and healthcare products during manufacturing and packaging process. High tendency of torn glove remaining in food or products due to white or light flesh-coloured glove is not easy to be detected by naked eyes. In this paper, iron oxide nanoparticles (IONs) selected as additive for NBR to improve its detectability by mean of magnetic properties. IONs synthesized via precipitation method and compounded with NBR latex before casting on petri dish. The properties of IONs were investigated by X-ray Diffractometry (XRD), Transmission Electron Microscope (TEM), Raman Spectroscopy and Vibrating Sample Magnetometer (VSM). Meanwhile NBR/IONs composites were studied by Thermogravimetry Analysis (TGA), Differential Scanning Calorimetry (DSC) and Vibrating Sample Magnetometer (VSM). It observed that, synthesized IONs shows of 25.28 nm crystallite with 25.86 nm semipherical (changed as) shape. Meanwhile, Magnetite and maghemite phase are found in range of 670 cm −1 and 700 cm −1 respectively, which it contributes magnetization saturation of 73.96 emu/g at 10,000 G by VSM. Thermal stability and magnetic properties were increased with incorporating IONs into NBR latex up to 20 phr. NBR/IONs 5 phr has the optimum thermal stability, lowest glass transition temperature (−14.83 °C) and acceptable range of magnetization saturation (3.83 emu/g at 10,000 G) to form NBR gloves with magnetic detectability. - Highlights: • We synthesized IONs with high magnetization saturation (M s ). • High M s of IONs were incorporated into NBR latex in order to induce magnetic properties in the NBR composite. • Introduction of IONs into NBR latex would improve thermal properties. • The produced NBR/IONs 5 phr composite exceeded the minimum magnetic moment sensor of the detector. • They have high potential for the

  7. Effect of magnetic and thermal properties of iron oxide nanoparticles (IONs) in nitrile butadiene rubber (NBR) latex

    Energy Technology Data Exchange (ETDEWEB)

    Ong, Hun Tiar; Julkapli, Nurhidayatullaili Muhd; Hamid, Sharifah Bee Abd, E-mail: sharifahbee@um.edu.my; Boondamnoen, O.; Tai, Mun Foong

    2015-12-01

    Nitrile butadiene rubber (NBR) gloves are one of the most important personal protective equipments but they are possible to tear off and contaminate food or pharmaceutical and healthcare products during manufacturing and packaging process. High tendency of torn glove remaining in food or products due to white or light flesh-coloured glove is not easy to be detected by naked eyes. In this paper, iron oxide nanoparticles (IONs) selected as additive for NBR to improve its detectability by mean of magnetic properties. IONs synthesized via precipitation method and compounded with NBR latex before casting on petri dish. The properties of IONs were investigated by X-ray Diffractometry (XRD), Transmission Electron Microscope (TEM), Raman Spectroscopy and Vibrating Sample Magnetometer (VSM). Meanwhile NBR/IONs composites were studied by Thermogravimetry Analysis (TGA), Differential Scanning Calorimetry (DSC) and Vibrating Sample Magnetometer (VSM). It observed that, synthesized IONs shows of 25.28 nm crystallite with 25.86 nm semipherical (changed as) shape. Meanwhile, Magnetite and maghemite phase are found in range of 670 cm{sup −1} and 700 cm{sup −1} respectively, which it contributes magnetization saturation of 73.96 emu/g at 10,000 G by VSM. Thermal stability and magnetic properties were increased with incorporating IONs into NBR latex up to 20 phr. NBR/IONs 5 phr has the optimum thermal stability, lowest glass transition temperature (−14.83 °C) and acceptable range of magnetization saturation (3.83 emu/g at 10,000 G) to form NBR gloves with magnetic detectability. - Highlights: • We synthesized IONs with high magnetization saturation (M{sub s}). • High M{sub s} of IONs were incorporated into NBR latex in order to induce magnetic properties in the NBR composite. • Introduction of IONs into NBR latex would improve thermal properties. • The produced NBR/IONs 5 phr composite exceeded the minimum magnetic moment sensor of the detector. • They have high

  8. Mineralogical and Thermal Properties of Poly(methyl methacrylate) Alite Composite

    International Nuclear Information System (INIS)

    Ismail, M.R.; El-Fass, M.M.; Abd-El-Rahman, H.A.; El-Miligy, A.A.

    1999-01-01

    The X-ray diffraction (XRD) characteristics and thermal stability of PMMA alite composite have been studied. The dried alite samples were impregnated by methyl methacrylate monomer and then subjected to gamma irradiation. The mineralogical and thermal properties of the PMMA alite composite materials were investigated by using XRD, DTA, and TGA techniques. The results indicate that, a markedly reduction of the peaks intensities of XRD for tricalcium silicate and calcium hydroxide. TGA data showed that PMMA alite composite has a high thermal stability as compared to PMMA

  9. Structure and Mechanical Properties of Al-Cu-Fe-X Alloys with Excellent Thermal Stability.

    Science.gov (United States)

    Školáková, Andrea; Novák, Pavel; Mejzlíková, Lucie; Průša, Filip; Salvetr, Pavel; Vojtěch, Dalibor

    2017-11-05

    In this work, the structure and mechanical properties of innovative Al-Cu-Fe based alloys were studied. We focused on preparation and characterization of rapidly solidified and hot extruded Al-Cu-Fe, Al-Cu-Fe-Ni and Al-Cu-Fe-Cr alloys. The content of transition metals affects mechanical properties and structure. For this reason, microstructure, phase composition, hardness and thermal stability have been investigated in this study. The results showed exceptional thermal stability of these alloys and very good values of mechanical properties. Alloying by chromium ensured the highest thermal stability, while nickel addition refined the structure of the consolidated alloy. High thermal stability of all tested alloys was described in context with the transformation of the quasicrystalline phases to other types of intermetallics.

  10. Studies on thermal properties and thermal control effectiveness of a new shape-stabilized phase change material with high thermal conductivity

    International Nuclear Information System (INIS)

    Cheng Wenlong; Liu Na; Wu Wanfan

    2012-01-01

    In order to overcome the difficulty of conventional phase change materials (PCMs) in packaging, the shape-stabilized PCMs are proposed to be used in the electronic device thermal control. However, the conventional shape-stabilized PCMs have the drawback of lower thermal conductivity, so a new shape-stabilized PCM with high thermal conductivity, which is suitable for thermal control of electronic devices, is prepared. The thermal properties of n-octadecane-based shape-stabilized PCM are tested and analyzed. The heat storage/release performance is studied by numerical simulation. Its thermal control effect for electronic devices is also discussed. The results show that the expanded graphite (EG) can greatly improve the thermal conductivity of the material with little effect on latent heat and phase change temperature. When the mass fraction of EG is 5%, thermal conductivity has reached 1.76 W/(m K), which is over 4 times than that of the original one. Moreover, the material has larger latent heat and good thermal stability. The simulation results show that the material can have good heat storage/release performance. The analysis of the effect of thermal parameters on thermal control effect for electronic devices provides references to the design of phase change thermal control unit. - Highlights: ► A new shape-stabilized PCM with higher thermal conductivity is prepared. ► The material overcomes the packaging difficulty of traditional PCMs used in thermal control unit. ► The EG greatly improves thermal conductivity with little effect on latent heat. ► The material has high thermal stability and good heat storage/release performance. ► The effectiveness of the material for electronic device thermal control is proved.

  11. Phase-change materials: vibrational softening upon crystallization and its impact on thermal properties

    Energy Technology Data Exchange (ETDEWEB)

    Matsunaga, Toshiyuki [Materials Science and Analysis Technology Centre, Panasonic Corporation, Osaka (Japan); Japan Synchrotron Radiation Research Institute Hyogo (Japan); Yamada, Noboru [Digital and Network Technology Development Centre, Panasonic Corporation, Osaka (Japan); Japan Synchrotron Radiation Research Institute Hyogo (Japan); Kojima, Rie [Digital and Network Technology Development Centre, Panasonic Corporation, Osaka (Japan); Shamoto, Shinichi [Neutron Science Research Centre, Japan Atomic Energy Research Institute, Ibaraki (Japan); Sato, Masugu; Tanida, Hajime; Uruga, Tomoya; Kohara, Shinji [Japan Synchrotron Radiation Research Institute, Hyogo (Japan); Takata, Masaki [SPring-8/RIKEN, Hyogo, Japan, Department of Advanced Materials Science, School of Frontier Sciences, The University of Tokyo, Chiba (Japan); Zalden, Peter; Bruns, Gunnar; Wuttig, Matthias [I. Physikalisches Institut und JARA-FIT, RWTH Aachen Univ. (Germany); Sergueev, Ilya [European Synchrotron Radiation Facility, Grenoble (France); Wille, Hans Christian [Deutsches Elektronen-Synchrotron, Hamburg (Germany); Hermann, Raphael Pierre [Juelich Centre for Neutron Science JCNS and Peter Gruenberg, Institut PGI, JARA-FIT, Forschungszentrum Juelich GmbH (Germany); Faculte des Sciences, Universite de Liege (Belgium)

    2011-06-21

    Crystallization of an amorphous solid is usually accompanied by a significant change of transport properties, such as an increase in thermal and electrical conductivity. This fact underlines the importance of crystalline order for the transport of charge and heat. Phase-change materials, however, reveal a remarkably low thermal conductivity in the crystalline state. The small change in this conductivity upon crystallization points to unique lattice properties. The present investigation reveals that the thermal properties of the amorphous and crystalline state of phase-change materials show remarkable differences such as higher thermal displacements and a more pronounced anharmonic behavior in the crystalline phase. These findings are related to the change of bonding upon crystallization, which leads to an increase of the sound velocity and a softening of the optical phonon modes at the same time. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Thermal properties of carbon black aqueous nanofluids for solar absorption

    Directory of Open Access Journals (Sweden)

    Han Dongxiao

    2011-01-01

    Full Text Available Abstract In this article, carbon black nanofluids were prepared by dispersing the pretreated carbon black powder into distilled water. The size and morphology of the nanoparticles were explored. The photothermal properties, optical properties, rheological behaviors, and thermal conductivities of the nanofluids were also investigated. The results showed that the nanofluids of high-volume fraction had better photothermal properties. Both carbon black powder and nanofluids had good absorption in the whole wavelength ranging from 200 to 2,500 nm. The nanofluids exhibited a shear thinning behavior. The shear viscosity increased with the increasing volume fraction and decreased with the increasing temperature at the same shear rate. The thermal conductivity of carbon black nanofluids increased with the increase of volume fraction and temperature. Carbon black nanofluids had good absorption ability of solar energy and can effectively enhance the solar absorption efficiency.

  13. Determining the thermal and physicals properties of oil processing products

    Directory of Open Access Journals (Sweden)

    Viktoria I. Kryvda

    2015-03-01

    Full Text Available In the last decades both technological process’ improvement and primary energy resources saving are the main tasks of oil refineries. Using various oil products does impose an accurate knowledge of their properties. The dispersion analysis applied makes possible to construct a model simulating the primary oil refining products’ and raw materials’ thermal physical properties. As a result of data approximation there were obtained polynomials with coefficients differing from attributable to the studied oil products fractions. The research represents graphic dependences of thermal physical properties on temperature values for diesel oil fraction. The linear character of density and calorific capacity dependencies from temperature is represented with a proportional error in calculations. The relative minimum error is below 2% that confirms the implemented calculations’ adequacy. The resulting model can be used in calculations for further technological process improvements.

  14. Preparation and investigations of thermal properties of copper oxide ...

    Indian Academy of Sciences (India)

    The effects of copper oxide, aluminium oxide and graphite on the thermal and structural properties of the organic ... solar energy, and heat regulation of electronics, biomedical ..... We gratefully acknowledge the financial support provided by.

  15. Thermal properties of redeposition layers in the JT-60U divertor region

    International Nuclear Information System (INIS)

    Ishimoto, Y.; Gotoh, Y.; Arai, T.; Masaki, K.; Miya, N.; Oyama, N.; Asakura, N.

    2006-01-01

    Thermal properties of the redeposition layer on the inner plate of the W-shaped divertor of JT-60U have been measured with laser flash method so as to estimate transient heat loads onto the divertor. Morphology analysis of the redeposition layer was conducted with a scanning electron microscope. Measurement of a redeposition layer sample of more than 200 μm thick, which had been produced near the most frequent striking point, showed following results: (1) the bulk density of the redeposition layer is about half of that of carbon fiber composite material; (2) the specific heat of the layer is roughly equal to that of the isotropic graphite; (3) the thermal conductivity of the redeposition layer is two orders of magnitude smaller than that of the carbon fiber composite. This low thermal conductivity of the redeposition layer is considered to be caused by a low graphitization degree of the redeposition layer. The difference between the divertor heat loads and the loss of the plasma stored energy becomes smaller taking account of thermal properties of the redeposition layer on the inner divertor, whereas estimated heat loads due to the ELMs is still larger than the loss. This is probably caused by the poloidal distribution of the thermal properties

  16. Cu-based shape memory alloys with enhanced thermal stability and mechanical properties

    International Nuclear Information System (INIS)

    Chung, C.Y.; Lam, C.W.H.

    1999-01-01

    Cu-based shape memory alloys were developed in the 1960s. They show excellent thermoelastic martensitic transformation. However the problems in mechanical properties and thermal instability have inhibited them from becoming promising engineering alloys. A new Cu-Zn-Al-Mn-Zr Cu-based shape memory alloy has been developed. With the addition of Mn and Zr, the martensitic transformation behaviour and the grain size ca be better controlled. The new alloys demonstrates good mechanical properties with ultimate tensile strenght and ductility, being 460 MPa and 9%, respectively. Experimental results revealed that the alloy has better thermal stability, i.e. martensite stabilisation is less serious. In ordinary Cu-Zn-Al alloys, martensite stabilisation usually occurs at room temperature. The new alloy shows better thermal stability even at elevated temperature (∝150 C, >A f =80 C). A limited small amount of martensite stabilisation was observed upon ageing of the direct quenched samples as well as the step quenched samples. This implies that the thermal stability of the new alloy is less dependent on the quenching procedure. Furthermore, such minor martensite stabilisation can be removed by subsequent suitable parent phase ageing. The new alloy is ideal for engineering applications because of its better thermal stability and better mechanical properties. (orig.)

  17. Laboratory-based grain-shape models for simulating dust infrared spectra

    NARCIS (Netherlands)

    Mutschke, H.; Min, M.; Tamanai, A.

    2009-01-01

    Context. Analysis of thermal dust emission spectra for dust mineralogy and physical grain properties depends on comparison spectra, which are either laboratory-measured infrared extinction spectra or calculated extinction cross sections based on certain grain models. Often, the agreement between

  18. Thermal and Mechanical Properties of Poly(butylene succinate Films Reinforced with Silica

    Directory of Open Access Journals (Sweden)

    Sangviroon Nanthaporn

    2015-01-01

    Full Text Available In recent year, bioplastics have become more popular resulting from the growing concerns on environmental issues and the rising fossil fuel price. However, their applications were limited by its mechanical and thermal properties. The aim of this research is thus to improve mechanical and thermal properties of PBS bioplastic films by reinforcing with silica. Due to the poor interfacial interaction between the PBS matrix and silica, glycidyl methacrylate grafted poly(butylene succinate (PBS-g-GMA was used as a compatibilizer in order to improve the interaction between bioplastic films and filler. PBS-g-GMA was prepared in a twin-screw extruder and analyzed by the FTIR spectrometer. PBS and silica were then mixed in a twin-screw extruder and processed into films by a chill-roll cast extruder. The effects of silica loading on thermal and mechanical properties of the prepared bioplastic films were investigated. It was found that the mechanical properties of PBS/silica composite films were improved when 1%wt of silica was added. However, the mechanical properties decreased with increasing silica loading due to the agglomeration of silica particles. The results also show that the silica/PBS films with PBS-g-GMA possessed improved mechanical properties over the films without the compatibilizer.

  19. Investigating properties of white noise in the undergraduate laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Umer; Shamim, Sohaib; Anwar, M Sabieh [School of Science and Engineering, Lahore University of Management Sciences (LUMS), Opposite Sector U, D.H.A, Lahore 54792 (Pakistan)], E-mail: umersiddiqui@lums.edu.pk, E-mail: sohaibshamim@lums.edu.pk, E-mail: sabieh@lums.edu.pk

    2009-09-15

    This paper describes a simple noise circuit for the undergraduate physics laboratory. Students use this circuit to study the properties of electrical noise on a personal computer. This is made possible by using a data acquisition system that allows the experimenters to obtain large amounts of data on the computer, suitable for subsequent mathematical computations. Various properties such as mean, noise power, noise power density and the probability distribution of noise voltages are also explored.

  20. Thermal degradation of N-rich organic laboratory analogues: new insight on the cosmomaterials organic precursor composition

    Science.gov (United States)

    Bonnet, J.-Y.; Quirico, E.; Buch, A.; Szopa, C.; Fray, N.; Cottin, H.; Thissen, R.

    2011-10-01

    The observed organic matter in the different objects, carbonaceous chondrites and IDPs, accessible to laboratory analyses is the result of a complex history. This history is divided into several phases the first of which take place into the presolar nebula and is followed by post accretional processes on the parent bodies [1, 2]. In the carbonaceous chondrites organic matter (both soluble and insoluble), nitrogen is a very minor constituent about 2wt%, but in micrometer scale localized zone of some IDPs the nitrogen content can reach values as high as 20wt% [1, 3]. Additionally, the Insoluble Organic Matter (IOM) polyaromatic structure suggests a formation through thermal processes of the organic precursor(s). In this IOM N-bearing cycles have been identified but not chemical functions like amino groups. The precursor(s) of all the organic matter observed in IOM and IDPs could then be nitrogen rich. To test this scenario, N-rich laboratory analogues, (polymeric solids) were thermally degraded at four different temperatures to simulate short time thermal processes in the solar nebula.

  1. Thermal and mechanical properties of fatty acid starch esters.

    Science.gov (United States)

    Winkler, H; Vorwerg, W; Rihm, R

    2014-02-15

    The current study examined thermal and mechanical properties of fatty acid starch esters (FASEs). All highly soluble esters were obtained by the sustainable, homogeneous transesterification of fatty acid vinyl esters in dimethylsulfoxide (DMSO). Casted films of products with a degree of substitution (DS) of 1.40-1.73 were compared with highly substituted ones (DS 2.20-2.63). All films were free of any plasticizer additives. Hydrophobic surfaces were characterized by contact angle measurements. Dynamic scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) revealed thermal transitions (T(g), T(m)) which were influenced by the internal plasticizing effect of the ester groups. Thermal gravimetric analysis (TGA) measurements showed the increased thermal stability toward native starch. Tensile tests revealed the decreasing strength and stiffness of the products with increasing ester-group chain length while the elongation increased up to the ester group laurate and after that decreased. Esters of the longest fatty acids, palmitate and stearate turned out to be brittle materials due to super molecular structures of the ester chains such as confirmed by X-ray. Summarized products with a DS 1.40-1.73 featured more "starch-like" properties with tensile strength up to outstanding 43 MPa, while products with a DS >2 behaved more "oil-like". Both classes of esters should be tested as a serious alternative to commercial starch blends and petrol-based plastics. The term Cnumber is attributed to the number of total C-Atoms of the fatty acid (e.g. C6=Hexanoate). Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Measurement of Thermal Radiation Properties of Solids

    Science.gov (United States)

    Richmond, J. C. (Editor)

    1963-01-01

    The overall objectives of the Symposium were to afford (1) an opportunity for workers in the field to describe the equipment and procedures currently in use for measuring thermal radiation properties of solids, (2) an opportunity for constructive criticism of the material presented, and (3) an open forum for discussion of mutual problems. It was also the hope of the sponsors that the published proceedings of the Symposium would serve as a valuable reference on measurement techniques for evaluating thermal radiation properties of solids, partic.ularly for those with limited experience in the field. Because of the strong dependence of emitted flux upon temperature, the program committee thought it advisable to devote the first session to a discussion of the problems of temperature measurement. All of the papers in Session I were presented at the request of and upon topics suggested by the Committee. Because of time and space limitations, it, was impossible to consider all temperature measurement problems that might arise--the objective was rather to call to the attention of the reader some of the problems that might be encountered, and to provide references that might provide solutions.

  3. Development of Methodologies for the Estimation of Thermal Properties Associated with Aerospace Vehicles

    Science.gov (United States)

    Scott, Elaine P.

    1996-01-01

    A thermal stress analysis is an important aspect in the design of aerospace structures and vehicles such as the High Speed Civil Transport (HSCT) at the National Aeronautics and Space Administration Langley Research Center (NASA-LaRC). These structures are complex and are often composed of numerous components fabricated from a variety of different materials. The thermal loads on these structures induce temperature variations within the structure, which in turn result in the development of thermal stresses. Therefore, a thermal stress analysis requires knowledge of the temperature distributions within the structures which consequently necessitates the need for accurate knowledge of the thermal properties, boundary conditions and thermal interface conditions associated with the structural materials. The goal of this proposed multi-year research effort was to develop estimation methodologies for the determination of the thermal properties and interface conditions associated with aerospace vehicles. Specific objectives focused on the development and implementation of optimal experimental design strategies and methodologies for the estimation of thermal properties associated with simple composite and honeycomb structures. The strategy used in this multi-year research effort was to first develop methodologies for relatively simple systems and then systematically modify these methodologies to analyze complex structures. This can be thought of as a building block approach. This strategy was intended to promote maximum usability of the resulting estimation procedure by NASA-LARC researchers through the design of in-house experimentation procedures and through the use of an existing general purpose finite element software.

  4. Characterization of thermal, hydraulic, and gas diffusion properties in variably saturated sand grades

    DEFF Research Database (Denmark)

    Deepagoda Thuduwe Kankanamge Kelum, Chamindu; Smits, Kathleen; Ramirez, Jamie

    2016-01-01

    porous media transport properties, key transport parameters such as thermal conductivity and gas diffusivity are particularly important to describe temperature-induced heat transport and diffusion-controlled gas transport processes, respectively. Despite many experimental and numerical studies focusing...... transport models (thermal conductivity, saturated hydraulic conductivity, and gas diffusivity). An existing thermal conductivity model was improved to describe the distinct three-region behavior in observed thermal conductivity–water saturation relations. Applying widely used parametric models for saturated......Detailed characterization of partially saturated porous media is important for understanding and predicting vadose zone transport processes. While basic properties (e.g., particle- and pore-size distributions and soil-water retention) are, in general, essential prerequisites for characterizing most...

  5. Structure and Mechanical Properties of Al-Cu-Fe-X Alloys with Excellent Thermal Stability

    Directory of Open Access Journals (Sweden)

    Andrea Školáková

    2017-11-01

    Full Text Available In this work, the structure and mechanical properties of innovative Al-Cu-Fe based alloys were studied. We focused on preparation and characterization of rapidly solidified and hot extruded Al-Cu-Fe, Al-Cu-Fe-Ni and Al-Cu-Fe-Cr alloys. The content of transition metals affects mechanical properties and structure. For this reason, microstructure, phase composition, hardness and thermal stability have been investigated in this study. The results showed exceptional thermal stability of these alloys and very good values of mechanical properties. Alloying by chromium ensured the highest thermal stability, while nickel addition refined the structure of the consolidated alloy. High thermal stability of all tested alloys was described in context with the transformation of the quasicrystalline phases to other types of intermetallics.

  6. Electrical resistivity and thermal properties of compatibilized multi-walled carbon nanotube/polypropylene composites

    Directory of Open Access Journals (Sweden)

    A. Szentes

    2012-06-01

    Full Text Available The electrical resistivity and thermal properties of multi-walled carbon nanotube/polypropylene (MWCNT/PP composites have been investigated in the presence of coupling agents applied for improving the compatibility between the nanotubes and the polymer. A novel olefin-maleic-anhydride copolymer and an olefin-maleic-anhydride copolymer based derivative have been used as compatibilizers to achieve better dispersion of MWCNTs in the polymer matrix. The composites have been produced by extrusion followed by injection moulding. They contained different amounts of MWCNTs (0.5, 2, 3 and 5 wt% and coupling agent to enhance the interactions between the carbon nanotubes and the polymer. The electrical resistivity of the composites has been investigated by impedance spectroscopy, whereas their thermal properties have been determined using a thermal analyzer operating on the basis of the periodic thermal perturbation method. Rheological properties, BET-area and adsorption-desorption isotherms have been determined. Dispersion of MWCNTs in the polymer has been studied by scanning electron microscopy (SEM.

  7. Study of the thermal properties of filaments for 3D printing

    International Nuclear Information System (INIS)

    Trhlíková, Lucie; Zmeskal, Oldrich; Florian, Pavel; Psencik, Petr

    2016-01-01

    Various materials are used for 3D printing, most commonly Acrylonitrile butadiene styrene (ABS), Polylactic acid (PLA), Polyethylene (PET) and Polypropylene (PP). These materials differ mainly in their melting point, which significantly influences the properties of the final products. Filaments are melted in the print head during the printing process. The temperature range is from 150 °C to 250 °C depending on the technology used. The optimum temperature for the cooling substrate on which printing is carried out is chosen so as to ensure uniform cooling and deformation. It generally varies between (40 – 100) °C. From the above it is clear that both temperatures can significantly affect the properties of the printed 3D object. It is therefore important to determine the thermal parameters (thermal conductivity, specific heat and thermal diffusivity) of the materials used across the entire range of temperatures. For evaluating the properties of different types of PLA materials, the step transient method was used, which allows determination of all required parameters using a fractal heat transfer model.

  8. Study of the thermal properties of filaments for 3D printing

    Energy Technology Data Exchange (ETDEWEB)

    Trhlíková, Lucie, E-mail: xctrhlikova@fch.vutbr.cz; Zmeskal, Oldrich, E-mail: zmeskal@fch.vutbr.cz; Florian, Pavel, E-mail: xcflorianp@fch.vutbr.cz [Faculty of Chemistry, Brno University of Technology, 612 00 Brno (Czech Republic); Psencik, Petr, E-mail: Petr.Psencik@ceitec.vutbr.cz [CEITEC, Brno University of Technology, 612 00 Brno (Czech Republic)

    2016-07-07

    Various materials are used for 3D printing, most commonly Acrylonitrile butadiene styrene (ABS), Polylactic acid (PLA), Polyethylene (PET) and Polypropylene (PP). These materials differ mainly in their melting point, which significantly influences the properties of the final products. Filaments are melted in the print head during the printing process. The temperature range is from 150 °C to 250 °C depending on the technology used. The optimum temperature for the cooling substrate on which printing is carried out is chosen so as to ensure uniform cooling and deformation. It generally varies between (40 – 100) °C. From the above it is clear that both temperatures can significantly affect the properties of the printed 3D object. It is therefore important to determine the thermal parameters (thermal conductivity, specific heat and thermal diffusivity) of the materials used across the entire range of temperatures. For evaluating the properties of different types of PLA materials, the step transient method was used, which allows determination of all required parameters using a fractal heat transfer model.

  9. Hydraulic and acoustic properties of the active Alpine Fault, New Zealand: Laboratory measurements on DFDP-1 drill core

    Science.gov (United States)

    Carpenter, B. M.; Kitajima, H.; Sutherland, R.; Townend, J.; Toy, V. G.; Saffer, D. M.

    2014-03-01

    We report on laboratory measurements of permeability and elastic wavespeed for a suite of samples obtained by drilling across the active Alpine Fault on the South Island of New Zealand, as part of the first phase of the Deep Fault Drilling Project (DFDP-1). We find that clay-rich cataclasite and principal slip zone (PSZ) samples exhibit low permeabilities (⩽10-18 m), and that the permeability of hanging-wall cataclasites increases (from c. 10-18 m to 10-15 m) with distance from the fault. Additionally, the PSZ exhibits a markedly lower P-wave velocity and Young's modulus relative to the wall rocks. Our laboratory data are in good agreement with in situ wireline logging measurements and are consistent with the identification of an alteration zone surrounding the PSZ defined by observations of core samples. The properties of this zone and the low permeability of the PSZ likely govern transient hydrologic processes during earthquake slip, including thermal pressurization and dilatancy strengthening.

  10. Influence of nanomaterials on properties of latent heat solar thermal energy storage materials – A review

    International Nuclear Information System (INIS)

    Raam Dheep, G.; Sreekumar, A.

    2014-01-01

    Highlights: • Classification of phase change materials. • Studies on phase change properties of various phase change materials. • Influence of nanomaterials on properties of phase change materials. - Abstract: Thermal energy storage system plays a critical role in developing an efficient solar energy device. As far as solar thermal devices are concerned, there is always a mismatch between supply and demand due to intermittent and unpredictable nature of solar radiation. A well designed thermal energy storage system is capable to alleviate this demerit by providing a constant energy delivery to the load. Many research works is being carried out to determine the suitability of thermal energy storage system to integrate with solar thermal gadgets. This review paper summarizes the numerous investigations on latent heat thermal energy storage using phase change materials (PCM) and its classification, properties, selection criteria, potential research areas and studies involved to analyze the thermal–physical properties of PCM

  11. Thermal and mechanical properties of TPU/PBT reinforced by carbon fiber

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jintao; Liu, Huanyu; Lu, Xiang; Qu, Jinping, E-mail: jpqu@scut.edu.cn [National Engineering Research Center of Novel Equipment for Polymer Processing, The Key Laboratory of Polymer Processing Engineering of the Ministry of Education, South China University of Technology, Guangzhou, 510640, Guangdong (China)

    2016-03-09

    In this study, thermal, mechanical properties and processability were performed on a series of carbon fiber (CF) filled thermoplastic polyurethane (TPU)/poly (butylene terephthalate) (PBT) composites to identify the effect of CF weight fraction on the properties of TPU/PBT. Scanning Electronic Microscope (SEM) show that CFs are uniformly dispersed in TPU/PBT matrix and there are no agglomerations. Melt flow index (MFI) show that the melt viscosity increased with the CF loading. Thermogravimetric analysis (TGA) revealed that the introduction of CF into organic materials tend to improve their thermal stability. The mechanical properties indicated that tensile strength and modulus, flexural strength and modulus, improved with an increase in CF loading, but the impact strength decreased by the loading of CF.

  12. Nanofluid Types, Their Synthesis, Properties and Incorporation in Direct Solar Thermal Collectors: A Review.

    Science.gov (United States)

    Chamsa-Ard, Wisut; Brundavanam, Sridevi; Fung, Chun Che; Fawcett, Derek; Poinern, Gerrard

    2017-05-31

    The global demand for energy is increasing and the detrimental consequences of rising greenhouse gas emissions, global warming and environmental degradation present major challenges. Solar energy offers a clean and viable renewable energy source with the potential to alleviate the detrimental consequences normally associated with fossil fuel-based energy generation. However, there are two inherent problems associated with conventional solar thermal energy conversion systems. The first involves low thermal conductivity values of heat transfer fluids, and the second involves the poor optical properties of many absorbers and their coating. Hence, there is an imperative need to improve both thermal and optical properties of current solar conversion systems. Direct solar thermal absorption collectors incorporating a nanofluid offers the opportunity to achieve significant improvements in both optical and thermal performance. Since nanofluids offer much greater heat absorbing and heat transfer properties compared to traditional working fluids. The review summarizes current research in this innovative field. It discusses direct solar absorber collectors and methods for improving their performance. This is followed by a discussion of the various types of nanofluids available and the synthesis techniques used to manufacture them. In closing, a brief discussion of nanofluid property modelling is also presented.

  13. Cellular and Porous Materials Thermal Properties Simulation and Prediction

    CERN Document Server

    Öchsner, Andreas; de Lemos, Marcelo J S

    2008-01-01

    Providing the reader with a solid understanding of the fundamentals as well as an awareness of recent advances in properties and applications of cellular and porous materials, this handbook and ready reference covers all important analytical and numerical methods for characterizing and predicting thermal properties. In so doing it directly addresses the special characteristics of foam-like and hole-riddled materials, combining theoretical and experimental aspects for characterization purposes.

  14. Thermal properties and modeling of aluminosilicate materials for low-temperature bulk applications

    International Nuclear Information System (INIS)

    Kaushal, S.

    1988-01-01

    This thesis concerns itself with the thermal properties of aluminosilicate materials such as cements, blended cements and clays and their application to the problem of radioactive waste encapsulation. The objective of this thesis is to study the thermal properties (heat of hydration, thermal conductivity and diffusivity) of these materials and to determine their effect on the temperature in large monoliths and on the material itself. In this thesis the hydration temperatures for the extreme conditions (adiabatic) were experimentally measured and compared to those predicted under real conditions. Such a simulation can be made by measuring the thermal properties and studying the temperature distribution predicted by a finite differences computer model. Measurements of adiabatic temperature rise were made using a computer-controlled adiabatic calorimeter which was designed and developed for this thesis. Conditions very close to zero heat exchange with the environment were achieved. The existence of this method made it possible to actually observe the fact that cement hydration results in boiling off of the water in such conditions. A number of additives were tried to prevent this. It was observed that waste or by-product materials such as blast furnace slag and fly ash could be used to dramatically reduced the temperature in large bodies. These materials also reacted extensively with the highly alkaline radioactive waste solution to form hydrogarnet and zeolitic material which had useful cementing properties. The conclusion was reached that a selection of blends of aluminosilicate materials can be utilized for providing the proper thermal environment for long-term geological disposal of radioactive waste

  15. Mechanical and Thermal Properties of Bamboo Pulp Fiber Reinforced Polyethylene Composites

    Directory of Open Access Journals (Sweden)

    Wenhan Ren

    2014-05-01

    Full Text Available The purpose of this study was to investigate the mechanical and thermal properties of high-density polyethylene (HDPE composites reinforced by bamboo pulp fibers (BPF. Using a twin-screw extruder, polymer composites were fabricated using BPF and bamboo flour (BF as the reinforcement and HDPE as the matrix. Tensile and flexural tests of the HDPE composites were performed to determine the mechanical properties under different conditions. The thermal properties of HDPE composites were characterized by thermogravimetric analysis (TGA and dynamic mechanical analysis (DMA. The results showed that BPF improved the mechanical and thermal properties of the polymer composites more than did BF. The tensile and flexural strength of composites with 30 wt% BPF were increased by 61.46% and 22.94%, respectively, while the tensile and flexural modulus were increased by 84.52% and 27.30%, respectively. Compared to composites with 50 wt% BF, the T5% of composites with 50 wt% BPF increased by 20.18 °C. As the BPF content increased, the storage modulus (E’ and loss modulus (E” initially increased, followed by a decrease. Compared to the BF/HDPE composites, BPF/HDPE composites reinforced at 30 wt% had a higher storage modulus (E’ and loss modulus (E” and lower damping parameter (tanδ.

  16. Mechanical properties and microstructure of long term thermal aged WWER 440 RPV steel

    Energy Technology Data Exchange (ETDEWEB)

    Kolluri, M., E-mail: kolluri@nrg.eu [Nuclear Research & Consultancy Group (NRG), P.O. Box 25, 1755 ZG Petten (Netherlands); Kryukov, A. [Scientific and Engineering Centre for Nuclear and Radiation Safety, 107140 Moscow (Russian Federation); Magielsen, A.J. [Nuclear Research & Consultancy Group (NRG), P.O. Box 25, 1755 ZG Petten (Netherlands); Hähner, P. [European Commission, Joint Research Centre, Directorate G – Nuclear Safety and Security, P.O. Box 2, 1755 ZG Petten (Netherlands); Petrosyan, V. [Armenian Scientific Research Institute for Nuclear Plant Operation (ARMATOM), 0027 Yerevan (Armenia); Sevikyan, G. [Armenian Nuclear Power Plant (ANPP), 0911, Metsamor, Armavir Marz (Armenia); Szaraz, Z. [European Commission, Joint Research Centre, Directorate G – Nuclear Safety and Security, P.O. Box 2, 1755 ZG Petten (Netherlands)

    2017-04-01

    The integrity assessment of the Reactor Pressure Vessel (RPV) is essential for the safe and Long Term Operation (LTO) of a Nuclear Power Plant (NPP). Hardening and embrittlement of RPV caused by neutron irradiation and thermal ageing are main reasons for mechanical properties degradation during the operation of an NPP. The thermal ageing-induced degradation of RPV steels becomes more significant with extended operational lives of NPPs. Consequently, the evaluation of thermal ageing effects is important for the structural integrity assessments required for the lifetime extension of NPPs. As a part of NRG's research programme on Structural Materials for safe-LTO of Light Water Reactor (LWR) RPVs, WWER-440 surveillance specimens, which have been thermal aged for 27 years (∼200,000 h) at 290 °C in a surveillance channel of Armenian-NPP, are investigated. Results from the mechanical and microstructural examination of these thermal aged specimens are presented in this article. The results indicate the absence of significant long term thermal ageing effect of 15Cr2MoV-A steel. No age hardening was detected in aged tensile specimens compared with the as-received condition. There is no difference between the impact properties of as-received and thermal aged weld metals. The upper shelf energy of the aged steel remains the same as for the as-received material at a rather high level of about 120 J. The T{sub 41} value did not change and was found to be about 10 °C. The microstructure of thermal aged weld, consisting carbides, carbonitrides and manganese-silicon inclusions, did not change significantly compared to as-received state. Grain-boundary segregation of phosphorus in long term aged weld is not significant either which has been confirmed by the absence of intergranular fracture increase in the weld. Negligible hardening and embrittlement observed after such long term thermal ageing is attributed to the optimum chemical composition of 15Cr2MoV-A for high

  17. Thermal and mechanical properties of polypropylene/titanium dioxide nanocomposite fibers

    International Nuclear Information System (INIS)

    Esthappan, Saisy Kudilil; Kuttappan, Suma Kumbamala; Joseph, Rani

    2012-01-01

    Highlights: ► Wet synthesis method was used for the synthesis of TiO 2 nano particles. ► Mechanical properties of polypropylene fibers were increased by the addition of TiO 2 nanoparticles. ► Thermal stability of polypropylene fiber was improved significantly by the addition of TiO 2 nano particles. ► TiO 2 nanoparticles dispersed well in polypropylene fibers. -- Abstract: Titanium dioxide nanoparticles were prepared by wet synthesis method and characterized by transmission electron microscopy and X-ray diffraction studies. The nanotitanium dioxide then used to prepare polypropylene/titanium dioxide composites by melt mixing method. It was then made into fibers by melt spinning and subsequent drawing. Mechanical properties of the fibers were studied using Favimat tensile testing machine with a load cell of 1200 cN capacity. Thermal behavior of the fibers was studied using differential scanning calorimetry and thermogravimetric analysis. Scanning electron microscope studies were used to investigate the titanium dioxide surface morphology and crosssection of the fiber. Mechanical properties of the polypropylene fiber was improved by the addition of titanium dioxide nanoparticles. Incorporation of nanoparticles improves the thermal stability of polypropylene. Differential scanning calorimetric studies revealed an improvement in crystallinity was observed by the addition of titanium dioxide nanoparticles.

  18. Temperature-dependent thermal properties of a paraffin phase change material embedded with herringbone style graphite nanofibers

    International Nuclear Information System (INIS)

    Warzoha, Ronald J.; Weigand, Rebecca M.; Fleischer, Amy S.

    2015-01-01

    Highlights: • The thermal properties of a PCM with nanofibers are determined. • The solid-phase thermal conductivity scales exponentially with volume fraction. • The liquid-phase thermal conductivity is only enhanced beyond a critical percolation threshold. • The nanoscale interface resistance depends on the nanoparticle’s dimensionality. • The thermal diffusivity and volumetric heat capacity of the nanoenhanced PCMs are found. - Abstract: In many studies, carbon nanoparticles with high values of thermal conductivity (10–3000 W/m K) have been embedded into phase change thermal energy storage materials (PCMs) in order to enhance their bulk thermal properties. While a great deal of work to date has focused on determining the effect of these nanoparticles on a PCM’s solid phase thermal properties, little is known about their effect on its liquid phase thermal properties. Thus, in this study, the effect of implanting randomly oriented herringbone style graphite nanofibers (HGNF, average diameter = 100 nm, average length = 20 μm) on the bulk thermal properties of an organic paraffin PCM (IGI 1230A, T melt = 329.15 K) in both the solid and liquid phase is quantified. The bulk thermal conductivity, volumetric heat capacity and thermal diffusivity of HGNF/PCM nanocomposites are obtained as a function of temperature and HGNF volume loading level. It is found that the property enhancement varies significantly depending on the material phase. In order to explain the difference between solid and liquid phase thermal properties, heat flow at the nanoparticle–PCM and nanoparticle–nanoparticle interfaces is examined as a function of HGNF loading level and temperature. To do this, the solid and liquid phase thermal boundary resistances (TBRs) between the nanoparticles and the surrounding PCM and/or between contacting nanoparticles are found. Results suggest that the TBR at the HGNF–PCM interface is nearly double the TBR across the HGNF–HGNF interface in

  19. Assessment of structural, thermal, and mechanical properties of portlandite through molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Hajilar, Shahin, E-mail: shajilar@iastate.edu [Department of Civil, Construction and Environmental Engineering, Iowa State University, Ames, IA 50011-1066 (United States); Shafei, Behrouz, E-mail: shafei@iastate.edu [Department of Civil, Construction and Environmental Engineering, Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011-1066 (United States)

    2016-12-15

    The structural, thermal, and mechanical properties of portlandite, the primary solid phase of ordinary hydrated cement paste, are investigated using the molecular dynamics method. To understand the effects of temperature on the structural properties of portlandite, the coefficients of thermal expansion of portlandite are determined in the current study and validated with what reported from the experimental tests. The atomic structure of portlandite equilibrated at various temperatures is then subjected to uniaxial tensile strains in the three orthogonal directions and the stress-strain curves are developed. Based on the obtained results, the effect of the direction of straining on the mechanical properties of portlandite is investigated in detail. Structural damage analysis is performed to reveal the failure mechanisms in different directions. The energies of the fractured surfaces are calculated in different directions and compared to those of the ideal surfaces available in the literature. The key mechanical properties, including tensile strength, Young's modulus, and fracture strain, are extracted from the stress-strain curves. The sensitivity of the obtained mechanical properties to temperature and strain rate is then explored in a systematic way. This leads to valuable information on how the structural and mechanical properties of portlandite are affected under various exposure conditions and loading rates. - Graphical abstract: Fracture mechanism of portlandite under uniaxial strain in the z-direction. - Highlights: • The structural, thermal, and mechanical properties of portlandite are investigated. • The coefficients of thermal expansion are determined. • The stress-strain relationships are studied in three orthogonal directions. • The effects of temperature and strain rate on mechanical properties are examined. • The plastic energy required for fracture in the crystalline structure is reported.

  20. Researches on thermal and rheological properties of cream- and vegetable spread

    Directory of Open Access Journals (Sweden)

    A. N. Ostrikov

    2016-01-01

    Full Text Available Researches of thermal and rheological properties of cream- and vegetable spread are necessary for the scientific substantiation of their obtaining process, namely mixing and crystallization processes. As the object of research, we chose a cream- and vegetable spread, with the following composition: peanut butter 10%; wheat germ oil 10%; linseed oil 20%; butter 59.8%; emulsifier 0.2%. With the data obtained in the course of research of the rheological properties of cream- and vegetable spread, one can subsequently generate recommendations for optimization of technological modes of production. In particular, one can solve problems of intensification of hydro-mechanical and thermal processes by carrying them out at such a temperature and speed when the maximum preservation of the produced product structure will be achieved. Determination of thermal characteristics was carried out in the apparatus for the study of thermal and rheological properties of viscoelastic liquids Coesfeld RT-1394H. Rheological researches of cream- and vegetable spread were carried out on a series of viscometers SV-10 and PB-8m. The graphs of spread dynamic viscosity dependence on the temperature, and the dependence of the effective viscosity of the spread and vegetable oils on the shear rate were built according to experimental data. The data obtained is rational to choose the equipment for processing and production of cream- and vegetable spread, to simulate processes taking place in the production process, to solve problems of intensification of thermal and hydro-mechanical processes reasonably, by conducting the production process at temperatures that do not cause the destruction of the product structure.

  1. Associated with aerospace vehicles development of methodologies for the estimation of thermal properties

    Science.gov (United States)

    Scott, Elaine P.

    1994-01-01

    Thermal stress analyses are an important aspect in the development of aerospace vehicles at NASA-LaRC. These analyses require knowledge of the temperature distributions within the vehicle structures which consequently necessitates the need for accurate thermal property data. The overall goal of this ongoing research effort is to develop methodologies for the estimation of the thermal property data needed to describe the temperature responses of these complex structures. The research strategy undertaken utilizes a building block approach. The idea here is to first focus on the development of property estimation methodologies for relatively simple conditions, such as isotropic materials at constant temperatures, and then systematically modify the technique for the analysis of more and more complex systems, such as anisotropic multi-component systems. The estimation methodology utilized is a statistically based method which incorporates experimental data and a mathematical model of the system. Several aspects of this overall research effort were investigated during the time of the ASEE summer program. One important aspect involved the calibration of the estimation procedure for the estimation of the thermal properties through the thickness of a standard material. Transient experiments were conducted using a Pyrex standard at various temperatures, and then the thermal properties (thermal conductivity and volumetric heat capacity) were estimated at each temperature. Confidence regions for the estimated values were also determined. These results were then compared to documented values. Another set of experimental tests were conducted on carbon composite samples at different temperatures. Again, the thermal properties were estimated for each temperature, and the results were compared with values obtained using another technique. In both sets of experiments, a 10-15 percent off-set between the estimated values and the previously determined values was found. Another effort

  2. On the thermal properties of polarized nuclear matter

    International Nuclear Information System (INIS)

    Hassan, M.Y.M.; Montasser, S.S.; Ramadan, S.

    1979-08-01

    The thermal properties of polarized nuclear matter are calculated using Skyrme III interaction modified by Dabrowski for polarized nuclear matter. The temperature dependence of the volume, isospin, spin and spin isospin pressure and energies are determined. The temperature, isospin, spin and spin isospin dependence of the equilibrium Fermi momentum is also discussed. (author)

  3. Response of mechanical properties of glasses to their chemical, thermal and mechanical histories

    DEFF Research Database (Denmark)

    Yue, Yuanzheng

    , surface, thermal history or excess entropy of the final glass state. Here I review recent progresses in understanding of the responses of mechanical properties of oxide glasses to the compositional variation, thermal history and mechanical deformation. The tensile strength, elastic modulus and hardness...... of glass fibers are dependent on the thermal history (measured as fictive temperature), tension, chemical composition and redox state. However, the fictive temperature affects the hardness of bulk glass in a complicated manner, i.e., the effect does not exhibit a clear regularity in the range...... and micro-cracks occurring during indentation of a glass is discussed briefly. Finally I describe the future perspectives and challenges in understanding responses of mechanical properties of oxide glasses to compositional variation, thermal history and mechanical deformation....

  4. Thermal Properties of Jojoba Oil Between 20°C and 45°C

    Science.gov (United States)

    Lara-Hernández, G.; Flores-Cuautle, J. J. A.; Hernandez-Aguilar, C.; Suaste-Gómez, E.; Cruz-Orea, A.

    2017-08-01

    Vegetable oils have been widely studied as biofuel candidates. Among these oils, jojoba ( Simmondsia chinensis) oil has attracted interest because it is composed almost entirely of wax esters that are liquid at room temperature. Consequently, it is widely used in the cosmetic and pharmaceutical industries. To date, research on S. chinensis oil has focused on to its use as a fuel and its thermal stability, and information about its thermal properties is scarce. In the present study, the thermal effusivity and conductivity of jojoba oil between 20°C and 45°C were obtained using the inverse photopyroelectric and hot-ball techniques. The feasibility of an inverse photopyroelectric method and a hot-ball technique to monitor the thermal conductivity, and the thermal effusivity of the S. chinensis is demonstrated. The thermal effusivity decreased from 538 W\\cdot s^{1/2}\\cdot m^{-2}\\cdot K^{-1} to 378 W\\cdot s^{1/2}m^{-2}\\cdot K^{-1} as the temperature increased, whereas the thermal conductivity remained the same over the temperature range investigated in this study. The obtained results provide insight into the thermal properties of S. chinensis oil between 20°C and 45°C.

  5. Low-temperature densification and excellent thermal properties of W–Cu thermal-management composites prepared from copper-coated tungsten powders

    International Nuclear Information System (INIS)

    Zhang, Lianmeng; Chen, Wenshu; Luo, Guoqiang; Chen, Pingan; Shen, Qiang; Wang, Chuanbin

    2014-01-01

    Highlights: • High-density (98.4%) W–20 wt.%Cu composites were low-temperature fabricated. • A highly pure Cu network and a homogenous microstructure formed in the composites. • The interfaces between W and Cu are well bonded with no spaces. • The composites have excellent thermal properties. -- Abstract: High-density W–20 wt.%Cu composites containing a Cu-network structure and exhibiting good thermal properties were fabricated by low-temperature hot-press sintering from high-purity copper-coated tungsten powders. The relative density of W–20 wt.%Cu composites sintered at 950 °C–100 MPa–2 h was 98.4%. The low-temperature densification of W–Cu composites occurs because the sintering mode of the coated particles involves only sintering of Cu to Cu, rather than both Cu to W and Cu to Cu, as required for conventional powder particles. The microstructure shows that a network of high-purity Cu extends throughout the composites, and that the W is distributed homogeneously; the interfaces between W and Cu show good contact. The composites have excellent thermal conductivity (239 W/(m K)) and a relatively low coefficient of thermal expansion (7.4 × 10 −6 /K), giving them some of the best properties reported to date for thermal-management materials. The excellent performance is mainly because of their structure, which arises from the characteristics of the high-purity copper-coated tungsten powders

  6. Crystal growth and comparison of vibrational and thermal properties ...

    Indian Academy of Sciences (India)

    The TGA–DTA studies showed the thermal properties of the crystals. ... impact on laser technology, optical communication and optical storage technology. [1,2]. .... UTHC and UTHS crystals in the temperature range of 25–1100◦C with a heat-.

  7. Effect of γ-irradiation on the thermal properties of UHMWPE ...

    Indian Academy of Sciences (India)

    irradiation on the thermal properties of UHMWPE/MWCNTs nanocomposites: a comparative study of incorporating unmodified and γ -ray-modified MWCNTs. SAQLAIN SAQIB MUKHTAR MALIK SAJJAD MEHMOOD SYED ASAD MAQBOOL ...

  8. Pumped Fluid Loop Heat Rejection and Recovery Systems for Thermal Control of the Mars Science Laboratory

    Science.gov (United States)

    Bhandari, Pradeep; Birur, Gajanana; Prina, Mauro; Ramirez, Brenda; Paris, Anthony; Novak, Keith; Pauken, Michael

    2006-01-01

    This viewgraph presentation reviews the heat rejection and heat recovery system for thermal control of the Mars Science Laboratory (MSL). The MSL mission will use mechanically pumped fluid loop based architecture for thermal control of the spacecraft and rover. The architecture is designed to harness waste heat from an Multi Mission Radioisotope Thermo-electric Generator (MMRTG) during Mars surface operations for thermal control during cold conditions and also reject heat during the cruise aspect of the mission. There are several test that are being conducted that will insure the safety of this concept. This architecture can be used during any future interplanetary missions utilizing radioisotope power systems for power generation.

  9. Examinations of Selected Thermal Properties of Packages of SiC Schottky Diodes

    Directory of Open Access Journals (Sweden)

    Bisewski Damian

    2016-09-01

    Full Text Available This paper describes the study of thermal properties of packages of silicon carbide Schottky diodes. In the paper the packaging process of Schottky diodes, the measuring method of thermal parameters, as well as the results of measurements are presented. The measured waveforms of transient thermal impedance of the examined diodes are compared with the waveforms of this parameter measured for commercially available Schottky diodes.

  10. Thermal analysis of borogypsum and its effects on the physical properties of Portland cement

    International Nuclear Information System (INIS)

    Elbeyli, Iffet Yakar; Derun, Emek Moeroeydor; Guelen, Jale; Piskin, Sabriye

    2003-01-01

    Borogypsum, which consists mainly of gypsum crystals, B 2 O 3 and some impurities, is formed during the production of boric acid from colemanite, which is an important borate ore. In this study, the effect of borogypsum and calcined borogypsum on the physical properties of ordinary Portland cement (OPC) has been investigated. The calcination temperature and transformations in the structures of borogypsum and natural gypsum were determined by differential thermal analysis (DTA), thermogravimetric analysis (TGA) and X-ray diffraction (XRD) techniques. Thermal experiments were carried out between ambient temperature and 500 deg. C in an air atmosphere at a heating rate of 10 deg. C min -1 . After calculation of enthalpy and determination of conversion temperatures, borogypsum (5% and 7%), hemihydrate borogypsum (5%) and natural gypsum (5%) were added separately to Portland cement clinker and cements were ground in the laboratory. The final products were tested for chemical analysis, compressive strength, setting time, Le Chatelier expansion and fineness properties according to the European Standard (EN 196). The results show that increasing the borogypsum level in Portland cement from 5% to 7% caused an increase in setting time and a decrease in soundness expansion and compressive strength. The cement prepared with borogypsum (5%) was found to have similar strength properties to those obtained with natural gypsum, whereas a mixture containing 5% of hemihydrate borogypsum was found to develop 25% higher compressive strength than the OPC control mixtures at 28 days. For this reason, utilization of calcined borogypsum in cement applications is expected to give better results than untreated borogypsum. It is concluded that hemihydrate borogypsum could be used as a retarder for Portland cement as an industrial side. This would play an important role in reducing environmental pollution

  11. Anisotropic elastic and thermal properties of titanium borides by first-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Liang; Gao, Yimin [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049 (China); Xiao, Bing [Department of Physics and Quantum Theory Group, School of Science and Engineering, Tulane University, New Orleans, LA 70118 (United States); Li, Yefei, E-mail: yefeili@126.com [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049 (China); Wang, Guoliang [State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049 (China)

    2013-12-05

    Highlights: •Elastic properties of titanium borides are calculated by first principles calculation. •Thermodynamical stability of titanium borides is analyzed. •Heat capacity and thermal expansion coefficient for titanium borides are calculated and compared. •Grüneisen parameters of titanium borides are calculated. -- Abstract: The anisotropic elastic and thermal expansions of the titanium borides (TiB{sub 2}, Ti{sub 3}B{sub 4}, TiB{sub P}nma and TiB{sub F}m3{sup ¯}m) are calculated from first-principles using density functional theory. All borides show different anisotropic elastic properties; the bulk, shear and Young’s moduli are consistent with those determined experimentally. The temperature dependence of thermal expansions is mainly caused by the restoration of thermal energy due to phonon excitations at low temperature. When the temperature is higher than 500 K, the volumetric coefficient is increased linearly by increasing temperature. Meanwhile, the heat capacities of titanium borides are obtained based on the knowledge of thermal expansion coefficient and the elasticity, the calculations are in good agreement with the experiments.

  12. Preparation and thermal properties of short carbon fibers/erythritol phase change materials

    International Nuclear Information System (INIS)

    Zhang, Qiang; Luo, Zhiling; Guo, Qilin; Wu, Gaohui

    2017-01-01

    Highlights: • Short carbon fiber (SCF)/erythritol phase change composites (PCCs) are prepared and tested. • The PCCs possess large heat capacity and high thermal conductivity. • The size of SCFs can affect thermal conductivities of SCF/erythritol PCCs. • The size of SCFs has negligible effects on melting points and enthalpies. • The SCF/erythritol PCCs show good temperature-regulated property. - Abstract: The thermal properties of the short carbon fibers (SCFs) filled erythritol phase change composites (PCCs) were investigated experimentally. The samples were prepared with different mass loadings of two kinds of SCFs, 1%, 2%, 4%, 7% and 10%. The melting points and phase change enthalpies were measured by differential scanning calorimeter (DSC). The effects of SCFs on the melting points are relatively small but the enthalpies were reduced with the loadings of SCFs. The greatest loss of enthalpies is 11.3% for composites filled with 10% SCFs. The thermal conductivities increased with the loadings of SCFs but not linearly. The highest thermal conductivity is 3.92 W/(m⋅K) for the composites with 10% longer SCFs, which was enhanced by 407.8% compared to pure erythritol (0.77 W/(m⋅K)). Composites filled with longer SCFs possess higher thermal conductivity and the mechanisms were discussed. A simple setup was made to test the temperature-regulated property of these materials. These include pure erythritol and phase change composites with different loading of SCFs. The PCCs have shown good application potential and the longer SCFs can lead to the better performance of PCCs.

  13. Chemical and thermal properties of VIP latrine sludge

    African Journals Online (AJOL)

    2015-07-04

    Jul 4, 2015 ... This study investigated the chemical and thermal properties of faecal sludge from 10 dry VIP latrines in Bester's Camp in the eThekwini Municipality, Durban, ... emptying and treatment equipment. A manual sorting of the pit .... (LaDePa) plant (Harrison and Wilson, 2012). Figure 3 illustrates the depths of the ...

  14. Preparation and characterization of molten salt based nanothermic fluids with enhanced thermal properties for solar thermal applications

    International Nuclear Information System (INIS)

    Madathil, Pramod Kandoth; Balagi, Nagaraj; Saha, Priyanka; Bharali, Jitalaxmi; Rao, Peddy V.C.; Choudary, Nettem V.; Ramesh, Kanaparthi

    2016-01-01

    Highlights: • Prepared and characterized inorganic ternary molten salt based nanothermic fluids. • MoS_2 and CuO nanoparticles incorporated ternary molten salts have been prepared. • Thermal properties enhanced by the addition of MoS_2 and CuO nanoparticles. • The amount of nanoparticles has been optimized. - Abstract: In the current energy scenario, solar energy is attracting considerable attention as a renewable energy source with ample research and commercial opportunities. The novel and efficient technologies in the solar energy are directed to develop methods for solar energy capture, storage and utilization. High temperature thermal energy storage systems can deal with a wide range of temperatures and therefore they are highly recommended for concentrated solar power (CSP) applications. In the present study, a systematic investigation has been carried out to identify the suitable inorganic nanoparticles and their addition in the molten salt has been optimized. In order to enhance the thermo-physical properties such as thermal conductivity and specific heat capacity of molten salt based HTFs, we report the utilization of MoS_2 and CuO nanoparticles. The enhancement in the above mentioned thermo-physical properties has been demonstrated for optimized compositions and the morphologies of nanoparticle-incorporated molten salts have been studied by scanning electron microscopy (SEM). Nanoparticle addition to molten salts is an efficient method to prepare thermally stable molten salt based heat transfer fluids which can be used in CSP plants. It is also observed that the sedimentation of nanoparticles in molten salt is negligible compared to that in organic heat transfer fluids.

  15. Synthesis, structural properties and thermal stability of Mn-doped hydroxyapatite

    Science.gov (United States)

    Paluszkiewicz, Czesława; Ślósarczyk, Anna; Pijocha, Dawid; Sitarz, Maciej; Bućko, Mirosław; Zima, Aneta; Chróścicka, Anna; Lewandowska-Szumieł, Małgorzata

    2010-07-01

    Hydroxyapatite (HA) - Ca 10(PO 4) 6(OH) 2 is a basic inorganic model component of hard biological tissues, such as bones and teeth. The significant property of HA is its ability to exchange Ca 2+ ions, which influences crystallinity, physico-chemical and biological properties of modified hydroxyapatite materials. In this work, FTIR, Raman spectroscopy, XRD, SEM and EDS techniques were used to determine thermal stability, chemical and phase composition of Mn containing hydroxyapatite (MnHA). Described methods confirmed thermal decomposition and phase transformation of MnHA to αTCP, βTCP and formation of Mn 3O 4 depending on sintering temperature and manganese content. In vitro biological evaluation of Mn-modified HA ceramics was also performed using human osteoblast cells.

  16. Nanofluid Types, Their Synthesis, Properties and Incorporation in Direct Solar Thermal Collectors: A Review

    Directory of Open Access Journals (Sweden)

    Wisut Chamsa-ard

    2017-05-01

    Full Text Available The global demand for energy is increasing and the detrimental consequences of rising greenhouse gas emissions, global warming and environmental degradation present major challenges. Solar energy offers a clean and viable renewable energy source with the potential to alleviate the detrimental consequences normally associated with fossil fuel-based energy generation. However, there are two inherent problems associated with conventional solar thermal energy conversion systems. The first involves low thermal conductivity values of heat transfer fluids, and the second involves the poor optical properties of many absorbers and their coating. Hence, there is an imperative need to improve both thermal and optical properties of current solar conversion systems. Direct solar thermal absorption collectors incorporating a nanofluid offers the opportunity to achieve significant improvements in both optical and thermal performance. Since nanofluids offer much greater heat absorbing and heat transfer properties compared to traditional working fluids. The review summarizes current research in this innovative field. It discusses direct solar absorber collectors and methods for improving their performance. This is followed by a discussion of the various types of nanofluids available and the synthesis techniques used to manufacture them. In closing, a brief discussion of nanofluid property modelling is also presented.

  17. Thermal conductivity and phase-change properties of aqueous alumina nanofluid

    International Nuclear Information System (INIS)

    Teng, Tun-Ping

    2013-01-01

    Highlights: ► The alumina nanofluid with chitosan was produced by two-step synthesis method. ► The k and phase-change properties of alumina nanofluid were examined. ► Adding Al 2 O 3 nanoparticles into water indeed improves the k. ► Adding the chitosan decreases the thermal conductivity of alumina nanofluid. ► The T cp and h c are 53.4% and 97.8% of those in DW with the optimal combination. - Abstract: This study uses thermal conductivity and differential scanning calorimeter experiments to explore the thermal conductivity and phase-change properties of alumina (Al 2 O 3 )–water nanofluid produced using a two-step synthesis method. Deionized water (DW) is used as a control group, and the Al 2 O 3 –water nanofluid uses chitosan as a dispersant. Nanoparticle morphology and materials were confirmed using transmission electron microscopy (TEM) and X-ray diffraction (XRD), respectively. The results show that adding Al 2 O 3 nanoparticles to DW improves DW thermal conductivity, but adding chitosan reduces the thermal conductivity of Al 2 O 3 –water nanofluid. Adding the nanoparticles to DW affects the phase-change peak temperature and phase change heat. The optimal combination is 0.1 wt.% chitosan and 0.5 wt.% Al 2 O 3 nanoparticles; the charging phase-change peak temperature and latent heat are 53.4% and 97.8% of those in DW, respectively

  18. Thermal creep effects on 20% cold worked AISI 316 mechanical properties

    International Nuclear Information System (INIS)

    Duncan, D.R.

    1980-09-01

    The effects of thermal creep on subsequent mechanical properties of 20% cold worked AISI 316 pressurized tubes were investigated. Specimens were subjected to temperatures of 811 to 977 0 K and stresses of 86 MPa to 276 MPa. This resulted in strains up to 1.3%. Subsequent mechanical property tests included load change stress rupture tests (original test pressure increased or decreased), uniaxial tensile tests, and temperature ramp burst tests. Load change stress rupture tests were consistent with predictions from isobaric tests, and thus, consistent with the linear life fraction rule. Tests with large stress increases and tests at 866 0 K displayed a tendency for earlier than predicted failure. Tensile and temperature ramp burst tests had only slight effects on material properties (property changes were attributed to thermal recovery). The test results showed that, under the conditions of investigation, dislocation structure recovery was the most significant effect of creep. 9 figures, 5 tables

  19. Mechanical, thermal and swelling properties of phosphorylated nanocellulose fibrils/PVA nanocomposite membranes.

    Science.gov (United States)

    Niazi, Muhammad Bilal Khan; Jahan, Zaib; Berg, Sigrun Sofie; Gregersen, Øyvind Weiby

    2017-12-01

    Cellulose nanofibrils (CNF) have strong reinforcing properties when incorporated in a compatible polymer matrix. This work reports the effect of the addition of phosphorylated nanocellulose (PCNF) on the mechanical, thermal and swelling properties of poly(vinyl alcohol) (PVA) nanocomposite membranes. The incorporation of nanocellulose in PVA reduced the crystallinity at 0%RH. However, when the films were exposed to higher humidities the crystallinity increased. No apparent trend is observed for mechanical properties for dry membranes (0% RH). However, at 93% RH the elastic modulus increased strongly from 0.12MPa to 0.82MPa when adding 6% PCNF. At higher humidities, the moisture uptake has large influence on storage modulus, tan δ and tensile properties. Membranes containing 1% PCNF absorbed most moisture. Swelling, thermal and mechanical properties indicate a good potential for applying of PVA/phosphorylated nanocellulose composite membranes for CO 2 separation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Radiation Improved Mechanical and Thermal Property of PP/HDPE

    International Nuclear Information System (INIS)

    Chaisupaditsin, M.; Thammit, C.; Techakiatkul, C.

    1998-01-01

    The mechanical properties, thermal properties and gel contents of PP-irradiated HDPE blends were studied. HDPE was gamma irradiated in the dose range of 10-30 kGy. The ratios of polymer blends of 30PP:70HDPE was mixed by a twin screw extruder at speed of 50 rpm. Irradiated HDPE with 30 kGy showed the highest gel contents. The blends ratio of 30PP:70HDPE (30 kGy) shows better heat resistance than the blends with non-irradiated HDPE. With increasing the radiation doses, the mechanical properties of the blends were improved

  1. Handbook on dielectric and thermal properties of microwaveable materials

    CERN Document Server

    Komarov, Vyacheslav V

    2012-01-01

    The application of microwave energy for thermal processing of different materials and substances is a rapidly growing trend in modern science and engineering. In fact, optimal design work involving microwaves is impossible without solid knowledge of the properties of these materials. Here s a practical reference that collects essential data on the dielectric and thermal properties of microwaveable materials, saving you countless hours on projects in a wide range of areas, including microwave design and heating, applied electrodynamics, food science, and medical technology. This unique book provides hard-to-find information on complex dielectric permittivity of media at industrial, scientific, and medical frequencies (430 MHz, 915MHz, 2.45GHz, 5.8 GHz, and 24.125GHz). Written by a leading expert in the field, this authoritative book does an exceptional job at presenting critical data on various materials and explaining what their key characteristics are concerning microwaves.

  2. Characterization of Hydrologic and Thermal Properties at Brady Geothermal Field, NV

    Science.gov (United States)

    Patterson, J.; Cardiff, M. A.; Lim, D.; Coleman, T.; Wang, H. F.; Feigl, K. L.

    2017-12-01

    Understanding and predicting the temperature evolution of geothermal reservoirs is a primary focus for geothermal power plant operators ensuring continued financial sustainability of the resource. Characterization of reservoir properties - such as thermal diffusivity and hydraulic conductivity - facilitates modeling efforts to develop a better understanding of temperature evolution. As part of the integrated "PoroTomo" experiment, borehole pressure measurements were collected in three monitoring wells of various depths under varying operational conditions at the Brady Geothermal Field near Reno, NV. During normal operational conditions, a vertical profile of borehole temperature to 330 m depth was collected using distributed temperature sensing (DTS) for a period of 5 days. Borehole pressure data indicates 2D flow and shows rapid responses to changes in pumping /injection rates, likely indicating fault-dominated flow. The temperature data show that borehole temperature recovery following cold water slug injection is variable with depth. Late time vertical temperature profiles show the borehole following a shallow geotherm to a depth of approximately 275 meters, below which the temperature declines until a depth of approximately 320 meters, with a stable zone of cold water forming below this, possibly indicating production-related thermal drawdown. A validated heat transfer model is used in conjunction with the temperature data to determine depth-dependent reservoir thermal properties. Hydraulic reservoir properties are determined through inversion of the collected pressure data using MODFLOW. These estimated thermal and hydraulic properties are synthesized with existing structural and stratigraphic datasets at Brady. The work presented herein was funded in part by the Office of Energy Efficiency and Renewable Energy (EERE), U.S. Department of Energy, under Award Number DE-EE0006760.

  3. The thermal properties of a carbon nanotube-enriched epoxy: Thermal conductivity, curing, and degradation kinetics

    KAUST Repository

    Ventura, Isaac Aguilar

    2013-05-31

    Multiwalled carbon nanotube-enriched epoxy polymers were prepared by solvent evaporation based on a commercially available epoxy system and functionalized multiwalled carbon nanotubes (COOH-MWCNTs). Three weight ratio configurations (0.05, 0.5, and 1.0 wt %) of COOH-MWCNTs were considered and compared with neat epoxy and ethanol-treated epoxy to investigate the effects of nano enrichment and processing. Here, the thermal properties of the epoxy polymers, including curing kinetics, thermal conductivity, and degradation kinetics were studied. Introducing the MWCNTs increased the curing activation energy as revealed by differential scanning calorimetry. The final thermal conductivity of the 0.5 and 1.0 wt % MWCNT-enriched epoxy samples measured by laser flash technique increased by up to 15% compared with the neat material. The activation energy of the degradation process, investigated by thermogravimetric analysis, was found to increase with increasing CNT content, suggesting that the addition of MWCNTs improved the thermal stability of the epoxy polymers. © 2013 Wiley Periodicals, Inc.

  4. Basic thermal-mechanical properties and thermal shock, fatigue resistance of swaged + rolled potassium doped tungsten

    Science.gov (United States)

    Zhang, Xiaoxin; Yan, Qingzhi; Lang, Shaoting; Xia, Min; Ge, Changchun

    2014-09-01

    The potassium doped tungsten (W-K) grade was achieved via swaging + rolling process. The swaged + rolled W-K alloy exhibited acceptable thermal conductivity of 159.1 W/m K and ductile-to-brittle transition temperature of about 873 K while inferior mechanical properties attributed to the coarse pores and small deformation degree. Then the thermal shock, fatigue resistance of the W-K grade were characterized by an electron beam facility. Thermal shock tests were conducted at absorbed power densities varied from 0.22 to 1.1 GW/m2 in a step of 0.22 GW/m2. The cracking threshold was in the range of 0.44-0.66 GW/m2. Furthermore, recrystallization occurred in the subsurface of the specimens tested at 0.66-1.1 GW/m2 basing on the analysis of microhardness and microstructure. Thermal fatigue tests were performed at 0.44 GW/m2 up to 1000 cycles and no cracks emerged throughout the tests. Moreover, recrystallization occurred after 1000 cycles.

  5. The Effect of Thermal Cycling Treatments on the Thermal Stability and Mechanical Properties of a Ti-Based Bulk Metallic Glass Composite

    Directory of Open Access Journals (Sweden)

    Fan Bu

    2016-11-01

    Full Text Available The effect of thermal cycling treatments on the thermal stability and mechanical properties of a Ti48Zr20Nb12Cu5Be15 bulk metallic glass composite (BMGC has been investigated. Results show that moderate thermal cycles in a temperature range of −196 °C (cryogenic temperature, CT to 25 °C (room temperature, RT or annealing time at CT has not induced obvious changes of thermal stability and then it decreases slightly over critical thermal parameters. In addition, the dendritic second phases with a bcc structure are homogeneously embedded in the amorphous matrix; no visible changes are detected, which shows structural stability. Excellent mechanical properties as high as 1599 MPa yield strength and 34% plastic strain are obtained, and the yield strength and elastic modulus also increase gradually. The effect on the stability is analyzed quantitatively by crystallization kinetics and plastic-flow models, and indicates that the reduction of structural relaxation enthalpy, which is related to the degradation of spatial heterogeneity, reduces thermal stability but does not imperatively deteriorate the plasticity.

  6. Coupled thermal stress analysis of a hollow circular cylinder with transversely isotropic properties

    International Nuclear Information System (INIS)

    Tanigawa, Y.; Ootao, Y.

    1987-01-01

    If we shall analyze the thermal stress problems exactly in a transient state in continuum media, discussed with both the coupling and inertia effect, it has be shown that the thermomechanical coupling term shows a significant role than the inertia term for the common commercial alloys. In the present paper, we have considered the continuum medium with transversely isotropic material property, which has an isotropic property in r-θ plane, and analyzed the transient thermal stress problem of an infinitely long hollow circular cylinder due to an axisymmetrical partial heating. In order to get the thermal and thermoelastic fundamental differential equations separated in each field, we have introduced a perturbation technique. And then, we have carried out numerical calculations for several values of thermal and thermoelastic orthotropical parameters. (orig./GL)

  7. Ethylene–propylene–diene terpolymer/hexa fluoropropylene–vinylidinefluoride dipolymer rubber blends: Thermal and mechanical properties

    International Nuclear Information System (INIS)

    Balachandran Nair, Ajalesh; Kurian, Philip; Joseph, Rani

    2012-01-01

    Highlights: ► The EPDM/MA-g-EPDM/FKM blends show good mechanical properties. ► In compatibilized blends, better thermal and swelling resistance was obtained. ► Random nucleation mechanism is the rate controlling process in degradation. ► Good phase morphology is obtained in the case of compatibilized blends. -- Abstract: Hexa fluoropropylene–vinylidinefluoride dipolymer, fluoroelastomer (FKM) and ethylene propylene diene rubber (EPDM) blends with and without compatibilizer (MA-g-EPDM) were prepared by two-roll mill mixing. The effects of blend ratio and amount of compatibilizer on mechanical properties and thermal stability were investigated. The cure characteristics and mechanical properties of EPDM, FKM and their blends of varying compositions were studied for unaged and aged samples. The 50:50 (w/w) FKM/EPDM showed highest mechanical properties. The tensile properties of all the composites, especially those with higher proportion of FKM increased with aging. Swelling of the blends was reduced after aging. The thermal stability of FKM/EPDM rubber blends was studied using thermogravimetric analysis (TGA). The incorporation of FKM rubber improved the thermal stability of EPDM rubber. The apparent degradation activation energy (E) of EPDM/FKM reactive blends was calculated by the Coats–Redfern method. The results showed that the EPDM/FKM reactive blends had higher thermal stability but lower E than FKM. The thermal degradation process of both EPDM/FKM reactive blends and FKM were determined by nucleation and growth mechanism. The differential scanning calorimetry (DSC) results suggest that glass transition temperature (T g ) peak for EPDM region is shifted to FKM phase, due to improved compatibility on addition of compatibilizer. The morphology of blends was investigated using scanning electron microscopy (SEM).

  8. Thermal properties of QED3 and confinement

    International Nuclear Information System (INIS)

    Novikov, M.Yu.; Shelest, V.P.; Sorin, A.S.; Tsejtlin, V.Yu.

    1986-01-01

    Thermal properties of quantum electrodynamics in 2+1 dimensions are studied. The systematic account of screening in the framework of the skeleton perturbation theory removes the infra-red divergencies of thermodynamic quantities and leads to the non-analytically of the type g 2 lng 2 . The polarizaion tensor, the thermodynamic potential and the fermion self-energy are investigated and the results obtained are used to discuss the possible absence of deconfinement in the model

  9. Effect of electron beam irradiation on thermal and mechanical properties of aluminum based epoxy composites

    Science.gov (United States)

    Visakh, P. M.; Nazarenko, O. B.; Sarath Chandran, C.; Melnikova, T. V.; Nazarenko, S. Yu.; Kim, J.-C.

    2017-07-01

    The epoxy resins are widely used in nuclear and aerospace industries. The certain properties of epoxy resins as well as the resistance to radiation can be improved by the incorporation of different fillers. This study examines the effect of electron beam irradiation on the thermal and mechanical properties of the epoxy composites filled with aluminum nanoparticles at percentage of 0.35 wt%. The epoxy composites were exposed to the irradiation doses of 30, 100 and 300 kGy using electron beam generated by the linear electron accelerator ELU-4. The effects of the doses on thermal and mechanical properties of the aluminum based epoxy composites were investigated by the methods of thermal gravimetric analysis, tensile test, and dynamic mechanical analysis. The results revealed that the studied epoxy composites showed good radiation resistance. The thermal and mechanical properties of the aluminum based epoxy composites increased with increasing the irradiation dose up to 100 kGy and decreased with further increasing the dose.

  10. Abnormal thermal expansion properties of cubic NaZn13-type La(Fe,Al)13 compounds.

    Science.gov (United States)

    Li, Wen; Huang, Rongjin; Wang, Wei; Zhao, Yuqiang; Li, Shaopeng; Huang, Chuanjun; Li, Laifeng

    2015-02-28

    The cubic NaZn13-type La(Fe,Al)13 compounds were synthesized, and their linear thermal expansion properties were investigated in the temperature range of 4.2-300 K. It was found that these compounds exhibit abnormal thermal expansion behavior, i.e., pronounced negative thermal expansion (NTE) or zero thermal expansion (ZTE) behavior, below the Curie temperature due to the magnetovolume effect (MVE). Moreover, in the La(Fe,Al)13 compounds, the modification of the coefficient of thermal expansion (CTE) as well as the abnormal thermal expansion (ATE) temperature-window is achieved through optimizing the proportion of Fe and Al. Typically, the average CTE of the LaFe13-xAlx compounds with x = 1.8 reaches as large as -10.47 × 10(-6) K(-1) between 100 and 225 K (ΔT = 125 K). Also, the ZTE temperature-window of the LaFe13-xAlx compounds with x = 2.5 and x = 2.7 could be broadened to 245 K (from 5 to 250 K). Besides, the magnetic properties of these compounds were measured and correlated with the abnormal thermal expansion behavior. The present results highlight the potential application of such La(Fe,Al)13 compounds with abnormal thermal expansion properties in cryogenic engineering.

  11. Analysis of soil hydraulic and thermal properties for land surface modeling over the Tibetan Plateau

    Science.gov (United States)

    Zhao, Hong; Zeng, Yijian; Lv, Shaoning; Su, Zhongbo

    2018-06-01

    Soil information (e.g., soil texture and porosity) from existing soil datasets over the Tibetan Plateau (TP) is claimed to be inadequate and even inaccurate for determining soil hydraulic properties (SHP) and soil thermal properties (STP), hampering the understanding of the land surface process over TP. As the soil varies across three dominant climate zones (i.e., arid, semi-arid and subhumid) over the TP, the associated SHP and STP are expected to vary correspondingly. To obtain an explicit insight into the soil hydrothermal properties over the TP, in situ and laboratory measurements of over 30 soil property profiles were obtained across the climate zones. Results show that porosity and SHP and STP differ across the climate zones and strongly depend on soil texture. In particular, it is proposed that gravel impact on porosity and SHP and STP are both considered in the arid zone and in deep layers of the semi-arid zone. Parameterization schemes for porosity, SHP and STP are investigated and compared with measurements taken. To determine the SHP, including soil water retention curves (SWRCs) and hydraulic conductivities, the pedotransfer functions (PTFs) developed by Cosby et al. (1984) (for the Clapp-Hornberger model) and the continuous PTFs given by Wösten et al. (1999) (for the Van Genuchten-Mualem model) are recommended. The STP parameterization scheme proposed by Farouki (1981) based on the model of De Vries (1963) performed better across the TP than other schemes. Using the parameterization schemes mentioned above, the uncertainties of five existing regional and global soil datasets and their derived SHP and STP over the TP are quantified through comparison with in situ and laboratory measurements. The measured soil physical properties dataset is available at https://data.4tu.nl/repository/uuid:c712717c-6ac0-47ff-9d58-97f88082ddc0" target="_blank">https://data.4tu.nl/repository/uuid:c712717c-6ac0-47ff-9d58-97f88082ddc0.

  12. Thermal property characterization of fine fibers by the 3-omega technique

    International Nuclear Information System (INIS)

    Xing, Changhu; Jensen, Colby; Munro, Troy; White, Benjamin; Ban, Heng; Chirtoc, Mihai

    2014-01-01

    The 3 omega method is one of few reliable measurement techniques for thermal characterization of micro to nanoscale suspended wires or fibers and has been applied for measurements of carbon nanotubes and silicon nanowires. However, the models described in the past were either complicated for analysis or simplified from a more complete solution. In addition, the past models cannot be implemented directly when using a more reliable measurement configuration with a Wheatstone bridge. In this work, a simpler, explicit model, is developed to describe the heat transfer process through a suspended wire for measurement of its thermal properties. Generic trends and values of the 3ω harmonic voltage amplitude and phase responses clearly indicate the frequency limits for thermal conductivity and heat capacity determination and ideal conditions for thermal diffusivity estimation. Based on a sensitivity analysis, these limits are confirmed and appropriate frequency ranges for thermal conductivity and diffusivity are recommended. Radiation influence on the measurement results is quantified and correlated to a dimensionless radiation parameter. Two methods are presented to determine sample thermal properties independent of lateral heat losses and validated by numerical experiments using COMSOL. Uncertainty analysis was also derived by Taylor series expansion with calculated parameter sensitivities. - Highlights: • An improved model for suspended wire 3 omega measurement. • Quantification on the radiation induced measurement error. • Numerical simulation validating the improved model. • Sensitivity analysis to find measurement range minimizing uncertainty

  13. Field Measurements Indicate Unexpected, Serious Underestimation of Mussel Heart Rates and Thermal Tolerance by Laboratory Studies.

    Directory of Open Access Journals (Sweden)

    Morgana Tagliarolo

    Full Text Available Attempts to predict the response of species to long-term environmental change are generally based on extrapolations from laboratory experiments that inevitably simplify the complex interacting effects that occur in the field. We recorded heart rates of two genetic lineages of the brown mussel Perna perna over a full tidal cycle in-situ at two different sites in order to evaluate the cardiac responses of the two genetic lineages present on the South African coast to temperature and the immersion/emersion cycle. "Robomussel" temperature loggers were used to monitor thermal conditions at the two sites over one year. Comparison with live animals showed that robomussels provided a good estimate of mussel body temperatures. A significant difference in estimated body temperatures was observed between the sites and the results showed that, under natural conditions, temperatures regularly approach or exceed the thermal limits of P. perna identified in the laboratory. The two P. perna lineages showed similar tidal and diel patterns of heart rate, with higher cardiac activity during daytime immersion and minimal values during daytime emersion. Comparison of the heart rates measured in the field with data previously measured in the laboratory indicates that laboratory results seriously underestimate heart rate activity, by as much as 75%, especially during immersion. Unexpectedly, field estimates of body temperatures indicated an ability to tolerate temperatures considered lethal on the basis of laboratory measurements. This suggests that the interaction of abiotic conditions in the field does not necessarily raise vulnerability to high temperatures.

  14. Experimental Investigation of Mechanical and Thermal Properties of Silica Nanoparticle-Reinforced Poly(acrylamide) Nanocomposite Hydrogels.

    Science.gov (United States)

    Zaragoza, Josergio; Babhadiashar, Nasim; O'Brien, Victor; Chang, Andrew; Blanco, Matthew; Zabalegui, Aitor; Lee, Hohyun; Asuri, Prashanth

    2015-01-01

    Current studies investigating properties of nanoparticle-reinforced polymers have shown that nanocomposites often exhibit improved properties compared to neat polymers. However, over two decades of research, using both experimental studies and modeling analyses, has not fully elucidated the mechanistic underpinnings behind these enhancements. Moreover, few studies have focused on developing an understanding among two or more polymer properties affected by incorporation of nanomaterials. In our study, we investigated the elastic and thermal properties of poly(acrylamide) hydrogels containing silica nanoparticles. Both nanoparticle concentration and size affected hydrogel properties, with similar trends in enhancements observed for elastic modulus and thermal diffusivity. We also observed significantly lower swellability for hydrogel nanocomposites relative to neat hydrogels, consistent with previous work suggesting that nanoparticles can mediate pseudo crosslinking within polymer networks. Collectively, these results indicate the ability to develop next-generation composite materials with enhanced mechanical and thermal properties by increasing the average crosslinking density using nanoparticles.

  15. Thermal Properties of Cement-Based Composites for Geothermal Energy Applications

    Science.gov (United States)

    Bao, Xiaohua; Memon, Shazim Ali; Yang, Haibin; Dong, Zhijun; Cui, Hongzhi

    2017-01-01

    Geothermal energy piles are a quite recent renewable energy technique where geothermal energy in the foundation of a building is used to transport and store geothermal energy. In this paper, a structural–functional integrated cement-based composite, which can be used for energy piles, was developed using expanded graphite and graphite nanoplatelet-based composite phase change materials (CPCMs). Its mechanical properties, thermal-regulatory performance, and heat of hydration were evaluated. Test results showed that the compressive strength of GNP-Paraffin cement-based composites at 28 days was more than 25 MPa. The flexural strength and density of thermal energy storage cement paste composite decreased with increases in the percentage of CPCM in the cement paste. The infrared thermal image analysis results showed superior thermal control capability of cement based materials with CPCMs. Hence, the carbon-based CPCMs are promising thermal energy storage materials and can be used to improve the durability of energy piles. PMID:28772823

  16. Thermal Properties of Cement-Based Composites for Geothermal Energy Applications

    Directory of Open Access Journals (Sweden)

    Xiaohua Bao

    2017-04-01

    Full Text Available Geothermal energy piles are a quite recent renewable energy technique where geothermal energy in the foundation of a building is used to transport and store geothermal energy. In this paper, a structural–functional integrated cement-based composite, which can be used for energy piles, was developed using expanded graphite and graphite nanoplatelet-based composite phase change materials (CPCMs. Its mechanical properties, thermal-regulatory performance, and heat of hydration were evaluated. Test results showed that the compressive strength of GNP-Paraffin cement-based composites at 28 days was more than 25 MPa. The flexural strength and density of thermal energy storage cement paste composite decreased with increases in the percentage of CPCM in the cement paste. The infrared thermal image analysis results showed superior thermal control capability of cement based materials with CPCMs. Hence, the carbon-based CPCMs are promising thermal energy storage materials and can be used to improve the durability of energy piles.

  17. Thermal Properties of Cement-Based Composites for Geothermal Energy Applications.

    Science.gov (United States)

    Bao, Xiaohua; Memon, Shazim Ali; Yang, Haibin; Dong, Zhijun; Cui, Hongzhi

    2017-04-27

    Geothermal energy piles are a quite recent renewable energy technique where geothermal energy in the foundation of a building is used to transport and store geothermal energy. In this paper, a structural-functional integrated cement-based composite, which can be used for energy piles, was developed using expanded graphite and graphite nanoplatelet-based composite phase change materials (CPCMs). Its mechanical properties, thermal-regulatory performance, and heat of hydration were evaluated. Test results showed that the compressive strength of GNP-Paraffin cement-based composites at 28 days was more than 25 MPa. The flexural strength and density of thermal energy storage cement paste composite decreased with increases in the percentage of CPCM in the cement paste. The infrared thermal image analysis results showed superior thermal control capability of cement based materials with CPCMs. Hence, the carbon-based CPCMs are promising thermal energy storage materials and can be used to improve the durability of energy piles.

  18. Multifunctional PLA-PHB/cellulose nanocrystal films: processing, structural and thermal properties.

    Science.gov (United States)

    Arrieta, M P; Fortunati, E; Dominici, F; Rayón, E; López, J; Kenny, J M

    2014-07-17

    Cellulose nanocrystals (CNCs) synthesized from microcrystalline cellulose by acid hydrolysis were added into poly(lactic acid)-poly(hydroxybutyrate) (PLA-PHB) blends to improve the final properties of the multifunctional systems. CNC were also modified with a surfactant (CNCs) to increase the interfacial adhesion in the systems maintaining the thermal stability. Firstly, masterbatch pellets were obtained for each formulation to improve the dispersion of the cellulose structures in the PLA-PHB and then nanocomposite films were processed. The thermal stability as well as the morphological and structural properties of nanocomposites was investigated. While PHB increased the PLA crystallinity due to its nucleation effect, well dispersed CNC and CNCs not only increased the crystallinity but also improved the processability, the thermal stability and the interaction between both polymers especially in the case of the modified CNCs based PLA-PHB formulation. Likewise, CNCs were better dispersed in PLA-CNCs and PLA-PHB-CNCs, than CNC. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Analysis of simplified heat transfer models for thermal property determination of nano-film by TDTR method

    Science.gov (United States)

    Wang, Xinwei; Chen, Zhe; Sun, Fangyuan; Zhang, Hang; Jiang, Yuyan; Tang, Dawei

    2018-03-01

    Heat transfer in nanostructures is of critical importance for a wide range of applications such as functional materials and thermal management of electronics. Time-domain thermoreflectance (TDTR) has been proved to be a reliable measurement technique for the thermal property determinations of nanoscale structures. However, it is difficult to determine more than three thermal properties at the same time. Heat transfer model simplifications can reduce the fitting variables and provide an alternative way for thermal property determination. In this paper, two simplified models are investigated and analyzed by the transform matrix method and simulations. TDTR measurements are performed on Al-SiO2-Si samples with different SiO2 thickness. Both theoretical and experimental results show that the simplified tri-layer model (STM) is reliable and suitable for thin film samples with a wide range of thickness. Furthermore, the STM can also extract the intrinsic thermal conductivity and interfacial thermal resistance from serial samples with different thickness.

  20. Development of fly ash boards with thermal, acoustic and fire insulation properties.

    Science.gov (United States)

    Leiva, C; Arenas, C; Vilches, L F; Alonso-Fariñas, B; Rodriguez-Galán, M

    2015-12-01

    This paper presents an experimental analysis on a new board composed of gypsum and fly ashes from coal combustion, which are mutually compatible. Physical and mechanical properties, sound absorption coefficient, thermal properties and leaching test have been obtained. The mechanical properties showed similar values to other commercial products. As far as the acoustic insulation characteristics are concerned, sound absorption coefficients of 0.3 and 0.8 were found. The board presents a low thermal conductivity and a fire resistance higher than 50 min (for 4 cm of thickness). The leaching of trace elements was below the leaching limit values. These boards can be considered as suitable to be used in building applications as partitions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Fabrication, thermal properties and thermal stabilities of microencapsulated n-alkane with poly(lauryl methacrylate) as shell

    International Nuclear Information System (INIS)

    Qiu, Xiaolin; Lu, Lixin; Wang, Ju; Tang, Guoyi; Song, Guolin

    2015-01-01

    Highlights: • Microencapsulation of octadecane and paraffin by crosslinked poly(lauryl methacrylate). • Octadecane microcapsules have a melting enthalpy of about 118 J g −1 . • Weight loss temperatures of the microcapsules were increased by 67 °C and 28 °C. • Phase change enthalpies decreased by around 10 wt% after 500 thermal cycles. • Foams with microcapsules can be applied for passive temperature control. - Abstract: Microencapsulation of n-octadecane or paraffin with poly(lauryl methacrylate) (PLMA) shell was performed by a suspension-like polymerization. The polymer shell was crosslinked by pentaerythritol tetraacrylate (PETRA). The surface morphologies of microcapsules were investigated by scanning electron microscopy (SEM). Phase change properties, thermal reliabilities and thermal stabilities of microcapsules were determined by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The n-octadecane microcapsule exhibits higher melting enthalpy (118.0 J g −1 ) and crystallization enthalpy (108.3 J g −1 ) compared with the paraffin microcapsule. The thermal resistant temperatures were enhanced by more than 25 °C when n-alkanes were microencapsulated by PLMA. The PCM contents of microcapsules decreased by less than 4 wt% and 6 wt% after 500 and 1000 thermal cycles, respectively. Heat-up experiments indicated that microcapsule-treated foams exhibited upgraded thermal regulation capacities. Consequently, microencapsulated n-octadecane or paraffin with PLMA as shell possesses good potentials for heat storage and thermal regulation.

  2. Laboratory technique for quantitative thermal emissivity ...

    Indian Academy of Sciences (India)

    Emission of radiation from a sample occurs due to thermal vibration of its .... Quantitative thermal emissivity measurements of geological samples. 393. Figure 1. ...... tral mixture modeling: A new analysis of rock and soil types at the Viking ...

  3. Results of the radiological survey at the former Alba Craft Laboratory site properties, Oxford, Ohio (OXO001)

    International Nuclear Information System (INIS)

    Murray, M.E.; Brown, K.S.; Mathis, R.A.

    1993-03-01

    At the request of the US Department of Energy (DOE), a team from Oak Ridge National Laboratory conducted a radiological survey at the former Alba Craft Laboratory Site Properties, Oxford, Ohio. The survey was performed in July and September of 1992. The purpose of the survey was to determine whether the property was contaminated with radioactive residues, primarily 238 U, from uranium machining operations conducted for National Lead of Ohio, a prime Atomic Energy Commission contractor. The survey included scan measurement of direct radiation levels inside and outside the former laboratory, outdoors on eight properties adjoining the former laboratory, and the city right-of-way adjacent to the surveyed properties. Radionuclide concentrations were determined in outdoor surface and subsurface soil samples taken from each property and the exterior of the laboratory. Fixed surface residual radioactivity was measured inside the laboratory and outside the building. Air samples were collected, direct exposure was measured, and samples were collected to measure transferable radioactivity inside the building. Results of the survey indicate areas where surface and soil contamination level s are above the DOE guidelines for uncontrolled areas

  4. Soil profile property estimation with field and laboratory VNIR spectroscopy

    Science.gov (United States)

    Diffuse reflectance spectroscopy (DRS) soil sensors have the potential to provide rapid, high-resolution estimation of multiple soil properties. Although many studies have focused on laboratory-based visible and near-infrared (VNIR) spectroscopy of dried soil samples, previous work has demonstrated ...

  5. MECHANICAL AND THERMAL PROPERTIES OF COMPOSITES FROM UNSATURATED POLYESTER FILLED WITH OIL PALM ASH

    Directory of Open Access Journals (Sweden)

    M.S. Ibrahim

    2012-06-01

    Full Text Available Oil palm ash (OPA is available in abundance, is renewable, can be obtained at no cost and shows good performance at high thermal conditions. Combinations of the unsaturated polyester with natural fillers have been reported to improve the mechanical and thermal properties of composites. Utilisation of oil palm ash as a filler in the manufacture of polymer composites can significantly reduce the requirement for other binders or matrixes of composite materials. This research uses oil palm ash as a filler to form composites through the investigation of the effect of different contents of filler on the properties of OPA-filled unsaturated polyester (UP/OPA composites. The effect of different volume fractions, i.e., 0, 10, 20 and 30 vol.% of oil palm ash introduced into 100, 90, 80 and 70 vol.% of an unsaturated polyester matrix on the composite mechanical properties, i.e., tensile and flexural, has been studied, together with thermal gravimetric analysis (TGA and differential scanning calorimetric (DSC. Specimens were prepared using compression moulding techniques based on the ASTM D790 and D5083 standards for flexural and tensile tests, respectively. The tensile and flexural mechanical properties of UP/OPA composites were improved in modulus by increasing the filler content. Thermal stability of the composites increased as the OPA filler content was increased, which was a logical consequence because of the high thermal stability of the silica compound of the OPA filler compared with that of the UP matrix. The results from the surface electron microscope (SEM analysis were the extension of mechanical and thermal tests.

  6. Phonon and thermal properties of achiral single wall carbon ...

    Indian Academy of Sciences (India)

    A detailed theoretical study of the phonon and thermal properties of achiral single wall carbon nanotubes has been carried out using force constant model considering up to third nearest-neighbor interactions. We have calculated the phonon dispersions, density of states, radial breathing modes (RBM) and the specific heats ...

  7. CO2 Insulation for Thermal Control of the Mars Science Laboratory

    Science.gov (United States)

    Bhandari, Pradeep; Karlmann, Paul; Anderson, Kevin; Novak, Keith

    2011-01-01

    The National Aeronautics and Space Administration (NASA) is sending a large (>850 kg) rover as part of the Mars Science Laboratory (MSL) mission to Mars in 2011. The rover's primary power source is a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) that generates roughly 2000 W of heat, which is converted to approximately 110 W of electrical power for use by the rover electronics, science instruments, and mechanism-actuators. The large rover size and extreme thermal environments (cold and hot) for which the rover is designed for led to a sophisticated thermal control system to keep it within allowable temperature limits. The pre-existing Martian atmosphere of low thermal conductivity CO2 gas (8 Torr) is used to thermally protect the rover and its components from the extremely cold Martian environment (temperatures as low as -130 deg C). Conventional vacuum based insulation like Multi Layer Insulation (MLI) is not effective in a gaseous atmosphere, so engineered gaps between the warm rover internal components and the cold rover external structure were employed to implement this thermal isolation. Large gaps would lead to more thermal isolation, but would also require more of the precious volume available within the rover. Therefore, a balance of the degree of thermal isolation achieved vs. the volume of rover utilized is required to reach an acceptable design. The temperature differences between the controlled components and the rover structure vary from location to location so each gap has to be evaluated on a case-by-case basis to arrive at an optimal thickness. For every configuration and temperature difference, there is a critical thickness below which the heat transfer mechanism is dominated by simple gaseous thermal conduction. For larger gaps, the mechanism is dominated by natural convection. In general, convection leads to a poorer level of thermal isolation as compared to conduction. All these considerations play important roles in the

  8. Effect of amorphisation on the thermal properties of nanostructured membranes

    Energy Technology Data Exchange (ETDEWEB)

    Termentzidis, Konstantinos; Verdier, Maxime; Lacroix, David [CNRS, LEMTA, UMR 7563, Vandoeuvre les Nancy (France); Lorraine Univ., Vandoeuvre les Nancy (France). LEMTA UMR 7563

    2017-05-01

    The majority of the silicon devices contain amorphous phase and amorphous/crystalline interfaces which both considerably affect the transport of energy carriers as phonons and electrons. In this article, we investigate the impact of amorphous phases (both amorphous silicon and amorphous SiO{sub 2}) of silicon nanoporous membranes on their thermal properties via molecular dynamics simulations. We show that a small fraction of amorphous phase reduces dramatically the thermal transport. One can even create nanostructured materials with subamorphous thermal conductivity, while keeping an important crystalline fraction. In general, the a-SiO{sub 2} shell around the pores reduces the thermal conductivity by a factor of five to ten compared to a-Si shell. The phonon density of states for several systems is also given to give the impact of the amorphisation on the phonon modes.

  9. Thermal behavior and mechanical properties of physically crosslinked PVA/Gelatin hydrogels.

    Science.gov (United States)

    Liu, Yurong; Geever, Luke M; Kennedy, James E; Higginbotham, Clement L; Cahill, Paul A; McGuinness, Garrett B

    2010-02-01

    Poly (vinyl alcohol)/Gelatin hydrogels are under active investigation as potential vascular cell culture biomaterials, tissue models and vascular implants. The PVA/Gelatin hydrogels are physically crosslinked by the freeze-thaw technique, which is followed by a coagulation bath treatment. In this study, the thermal behavior of the gels was examined by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). Rheological measurement and uniaxial tensile tests revealed key mechanical properties. The role of polymer fraction in relation to these mechanical properties is explored. Gelatin has no significant effect on the thermal behavior of PVA, which indicates that no substantial change occurs in the PVA crystallite due to the presence of gelatin. The glass transition temperature, melting temperature, degree of crystallinity, polymer fraction, storage modulus (G') and ultimate strength of one freeze-thaw cycle (1FT) hydrogels are inferior to those of 3FT hydrogels. With coagulation, both 1FT and 3FT hydrogels shifted to a lower value of T(g), melting temperature and polymer fraction are further increased and the degree of crystallinity is depressed. The mechanical properties of 1FT, but not 3FT, were strengthened with coagulation treatment. This study gives a detailed investigation of the microstructure formation of PVA/Gelatin hydrogel in each stage of physical treatments which helps us to explain the role of physical treatments in tuning their physical properties for biomechanical applications. Copyright 2009 Elsevier Ltd. All rights reserved.

  10. Influence of polypropylene fibres on the tensile strength and thermal properties of various densities of foamed concrete

    Science.gov (United States)

    Jhatial, Ashfaque Ahmed; Inn, Goh Wan; Mohamad, Noridah; Johnson Alengaram, U.; Mo, Kim Hung; Abdullah, Redzuan

    2017-11-01

    As almost half of the world’s population now lives in the urban areas, the raise in temperature in these areas has necessitated the development of thermal insulating material. Conventional concrete absorbs solar radiation during the daytime while releasing it at night causing raise in temperature in urban areas. The thermal conductivity of 2200 kg/m3 density conventional concrete is 1.6 W/mK. Higher the thermal conductivity value, greater the heat flow through the material. To reduce this heat transfer, the construction industry has turned to lightweight foamed concrete. Foamed concrete, due to its air voids, gives excellent thermal properties and sound absorption apart from fire-resistance and self-leveling properties. But due to limited studies on different densities of foamed concrete, the thermal properties are not understood properly thus limiting its use as thermal insulating material. In this study, thermal conductivity is determined for 1400, 1600 and 1800 kg/m3 densities of foamed concrete. 0.8% of Polypropylene fibres (PP) is used to reinforce the foamed concrete and improve the mechanical properties. Based upon the results, it was found that addition of PP fibres enhances the tensile strength and slightly reduced the thermal conductivity for lower densities, while the reverse affect was noticed in 1800 kg/m3 density.

  11. Effects of alkali treatment on the mechanical and thermal properties of Sansevieria trifasciata fiber

    Science.gov (United States)

    Mardiyati, Steven, Rizkiansyah, Raden Reza; Senoaji, A.; Suratman, R.

    2016-04-01

    In this study, Sansevieria trifasciata fibers were treated by NaOH with concentration 1%,3%, and 5wt% at 100°C for 2 hours. Chesson-Datta methods was used to determine the lignocellulose content of raw sansevieria fibers and to investigate effect of alkali treatment on lignin content of the fiber. Mechanical properties and thermal properties of treated and untreated fibers were measured by means of tensile testing machine and thermogravimetric analysis (TGA).The cellulose and lignin contents of raw sansevieria fiber obtained from Chesson-Datta method were 56% and 6% respectively. Mechanical testing of fibers showed the increase of tensile strength from 647 MPa for raw fibers to 902 MPa for 5wt% NaOH treated fibers. TGA result showed the alkali treatment increase the thermal resistance of fibers from 288°C for raw fibers to 307°C for 5% NaOH treated fiber. It was found that alkali treatment affect the mechanical properties and thermal properties of sansevieria fibers.

  12. Project development laboratories energy fuels and oils based on NRU “MPEI”

    Science.gov (United States)

    Burakov, I. A.; Burakov, A. Y.; Nikitina, I. S.; Khomenkov, A. M.; Paramonova, A. O.; Khtoo Naing, Aung

    2017-11-01

    In the process of improving the efficiency of power plants a hot topic is the use of high-quality fuels and lubricants. In the process of transportation, preparation for use, storage and maintenance of the properties of fuels and lubricants may deteriorate, which entails a reduction in the efficiency of power plants. One of the ways to prevent the deterioration of the properties is a timely analysis of the relevant laboratories. In this day, the existence of laboratories of energy fuels and energy laboratory oil at thermal power stations is satisfactory character. However, the training of qualified personnel to work in these laboratories is a serious problem, as the lack of opportunities in these laboratories a complete list of required tests. The solution to this problem is to explore the possibility of application of methods of analysis of the properties of fuels and lubricants in the stage of training and re-training of qualified personnel. In this regard, on the basis of MPEI developed laboratory projects of solid, liquid and gaseous fuels, power and energy oils and lubricants. Projects allow for a complete list of tests required for the timely control of properties and prevent the deterioration of these properties. Assess the financial component of the implementation of the developed projects based on the use of modern equipment used for tests. Projects allow for a complete list of tests required for the timely control of properties and prevent the deterioration of these properties.

  13. Effect of Mo content on thermal and mechanical properties of Mo–Ru–Rh–Pd alloys

    International Nuclear Information System (INIS)

    Masahira, Yusuke; Ohishi, Yuji; Kurosaki, Ken; Muta, Hiroaki; Yamanaka, Shinsuke; Komamine, Satoshi; Fukui, Toshiki; Ochi, Eiji

    2015-01-01

    Metallic inclusions are precipitated in irradiated oxide fuels. The composition of the phases varies with the burnup and the conditions such as temperature gradients and oxygen potential of the fuel. In the present work, Mo x/(0.7+x) (Ru 0.5 Rh 0.1 Pd 0.1 ) (0.7)/(0.7+x) (x = 0, 0.05, 0.1, 0.15, 0.2, and 0.25) alloys were prepared by arc melting, followed by annealing in a high vacuum. The thermal and mechanical properties of the alloys such as elastic moduli, Debye temperature, micro-Vickers hardness, electrical resistivity, and thermal conductivity have been evaluated to elucidate the effect of Mo content on these physical properties of the alloys. The alloys with lower Mo contents show higher thermal conductivity. The thermal conductivity of the alloy with x = 0 is almost twice of that of the alloy with x = 0.25. The thermal conductivities of the alloys are dominated by electronic contribution, which has been evaluated using the Wiedemann–Franz–Lorenz relation from the electrical resistivity data. It is confirmed that the variation of the Mo contents of the alloys considerably affects the mechanical and thermal properties of the alloys

  14. Thermal Behaviour of clay formations

    International Nuclear Information System (INIS)

    Tassoni, E.

    1985-01-01

    The programme carried out by ENEA to model the thermal-hydraulic-mechanical behaviour of the clay formations and to measure, in situ and in laboratory, the thermal properties of these rocks, is presented. An in situ heating experiment has been carried out in an open clay quarry in the area of Monterotondo, near Rome. The main goal of the experiment was to know the temperature field and the thermal effects caused by the high level radioactive waste disposed of in a clayey geological formation. The conclusions are as follows: - the thermal conduction codes are sufficiently accurate to forecast the temperature increases caused in the clay by the dissipation of the heat generated by high level radioactive waste; - the thermal conductivity deduced by means of the ''curve fitting'' method ranges from 0.015 to 0.017 W.cm -1 . 0 C -1 - the temperature variation associated with the transport of clay interstitial water caused by temperature gradient is negligible. A laboratory automated method has been designed to measure the thermal conductivity and diffusivity in clay samples. A review of experimental data concerning thermomechanical effects in rocks as well as results of thermal experiments performed at ISMES on clays are presented. Negative thermal dilation has been found both in the elastic and plastic range under constant stress. Thermoplastic deformation appears ten times greater than the thermoelastic one. A mathematical model is proposed in order to simulate the above and other effects that encompass thermal-elastic-plastic-pore water pressure response of clays at high temperature and effective pressure with undrained and transient drainage conditions. Implementation of the two versions into a finite element computer code is described

  15. Thermal Properties of the Silicon Microstrip Endcap Detector

    CERN Document Server

    Feld, Lutz; Hammarström, R

    1998-01-01

    Irradiated silicon detectors must be cooled in order to guarantee stable short and long term operation. Using the SiF1 milestone prototype we have performed a detailed analysis of the thermal properties of the silicon microstrip endcap detector. The strongest constraint on the cooling system is shown to be set by the need to avoid thermal runaway of the silicon detectors. We show that, taking into account the radiation damage to the silicon after 10 years of LHC operation and including some safety margin, the detector will need a cooling fluid temperature of around -20 C. The highest temperature on the silicon will then be in the range -15 C to -10 C. This sets an upper limit on the ambient temperature in the tracker volume.

  16. Effects of electron irradiation in space environment on thermal and mechanical properties of carbon fiber/bismaleimide composite

    International Nuclear Information System (INIS)

    Yu, Qi; Chen, Ping; Gao, Yu; Ma, Keming; Lu, Chun; Xiong, Xuhai

    2014-01-01

    Highlights: •Electron irradiation decreased the storage modulus finally. •T g decreased first and then increased and finally decreased. •The thermal stability was reduced and then improved and finally decreased. •The changing trend of flexural strength and ILSS are consistent. -- Abstract: The effects of electron irradiation in simulated space environment on thermal and mechanical properties of high performance carbon fiber/bismaleimide composites were investigated. The dynamic mechanical properties of the composites exposed to different fluences of electron irradiation were evaluated by Dynamic mechanical analysis (DMA). Thermogravimetric analysis was applied to investigate the changes in thermal stability of the resin matrix after exposure to electron irradiation. The changes in mechanical properties of the composites were evaluated by flexural strength and interlaminar shear strength (ILSS). The results indicated that electron irradiation in high vacuum had an impact on thermal and mechanical properties of CF/BMI composites, which depends on irradiation fluence. At lower irradiation fluences less than 5 × 10 15 cm −2 , the dynamic storage modulus, cross-linking degree, thermal stability and mechanical properties that were determined by a competing effect between chain scission and cross-linking process, decreased firstly and then increased. While at higher fluences beyond 5 × 10 15 cm −2 , the chain scission process was dominant and thus led to the degradation in thermal and mechanical properties of the composites

  17. Effect of thermal-treatment sequence on sound absorbing and mechanical properties of porous sound-absorbing/thermal-insulating composites

    Directory of Open Access Journals (Sweden)

    Huang Chen-Hung

    2016-01-01

    Full Text Available Due to recent rapid commercial and industrial development, mechanical equipment is supplemented massively in the factory and thus mechanical operation causes noise which distresses living at home. In livelihood, neighborhood, transportation equipment, jobsite construction noises impact on quality of life not only factory noise. This study aims to preparation technique and property evaluation of porous sound-absorbing/thermal-insulating composites. Hollow three-dimensional crimp PET fibers blended with low-melting PET fibers were fabricated into hollow PET/low-melting PET nonwoven after opening, blending, carding, lapping and needle-bonding process. Then, hollow PET/low-melting PET nonwovens were laminated into sound-absorbing/thermal-insulating composites by changing sequence of needle-bonding and thermal-treatment. The optimal thermal-treated sequence was found by tensile strength, tearing strength, sound-absorbing coefficient and thermal conductivity coefficient tests of porous composites.

  18. Mechanical and thermal properties of phthalonitrile resin reinforced with silicon carbide particles

    International Nuclear Information System (INIS)

    Derradji, Mehdi; Ramdani, Noureddine; Zhang, Tong; Wang, Jun; Feng, Tian-tian; Wang, Hui; Liu, Wen-bin

    2015-01-01

    Highlights: • SiC microparticles improve the mechanical properties of phthalonitrile resin. • Excellent thermal stability achieved by adding SiC particles in phthalonitrile resin. • Adding 20 wt.% of SiC microparticles increases the T g by 38 °C. • Silane coupling agent can enhance the adhesion and dispersion of particles/matrix. - Abstract: A new type of composite based on phthalonitrile resin reinforced with silicon carbide (SiC) microparticles was prepared. For various weight ratios ranging between 0% and 20%, the effect of the micro-SiC particles on the mechanical and thermal properties has been studied. Results from thermal analysis revealed that the starting decomposition temperature and the residual weight were significantly improved upon adding the reinforcing phase. At the maximum micro-SiC loading, dynamic mechanical analysis (DMA) showed an important enhancement in both the storage modulus and glass transition temperature (T g ), reaching 3.1 GPa and 338 °C, respectively. The flexural strength and modulus as well as the microhardness were significantly enhanced by adding the microfillers. Tensile test revealed enhancements in the composites toughness upon adding the microparticles. Polarization optical microscope (POM) and scanning electron microscope (SEM) analysis confirmed that mechanical and thermal properties improvements are essentially attributed to the good dispersion and adhesion between the particles and the resin

  19. Mechanical and thermal properties of environmentally friendly composites derived from sugar palm tree

    International Nuclear Information System (INIS)

    Sahari, J.; Sapuan, S.M.; Zainudin, E.S.; Maleque, M.A.

    2013-01-01

    Highlights: ► We successfully developed biocomposites derived from sugar palm tree. ► The addition of SPF improve the mechanical properties of biocomposites. ► The thermal stability of biocomposites increase with increasing of SPF. ► The water absorption of biocomposites decrease with increasing of SPF. ► We investigate the morphological fracture through scanning electron microscopy. - Abstract: The aim of this paper is to study the effect of fibre content on mechanical properties, water absorption behaviour and thermal properties of sugar palm fibre (SPF) reinforced plasticized sugar palm starch (SPF/SPS) biocomposites. The biocomposites were prepared with different amounts of fibres (i.e. 10%, 20% and 30% by weight percent) by using glycerol as plasticizer for the starch. The mechanical properties of plasticized SPS improved with the incorporation of fibres. Fibre loading also increased the thermal stability of the biocomposite in this investigation. Water uptake and moisture content of SPF/SPS biocomposites decreased with the incorporation of fibres, which is due to better interfacial bonding between the matrix and fibres as well as the hindrance to absorption caused by the fibres. Fractographic studies through scanning electron microscopy showed homogeneous distribution of fibres and matrix with good adhesion which play an important role in improving the mechanical properties of biocomposites

  20. Thermal and mechanical properties of bio-based plasticizers mixtures on poly (vinyl chloride

    Directory of Open Access Journals (Sweden)

    Boussaha Bouchoul

    2017-09-01

    Full Text Available Abstract The use of mixtures of nontoxic and biodegradable plasticizers coming from natural resources is a good way to replace conventional phthalates plasticizers. In this study, two secondary plasticizers of epoxidized sunflower oil (ESO and epoxidized sunflower oil methyl ester (ESOME were synthesized and have been used with two commercially available biobased plasticizers; isosorbide diesters (ISB and acetyl tributyl citrate (ATBC in order to produce flexible PVC. Different mixtures of these plasticizers have been introduced in PVC formulations. Thermal, mechanical and morphological properties have been studied by using discoloration, thermogravimetric analysis (TGA, differential scanning calorimetry (DSC, dynamic mechanical thermal analysis (DMTA, tensile - strain and scanning electron microscopy (SEM. Studies have shown that PVC plasticization and stabilization were improved by addition of plasticizers blends containing ISB, ATBC, ESO and ESOME. An increase in the content of ESO or ESOME improved thermal and mechanical properties, whereas ESOME/ATBC formulations exhibited the best properties.

  1. Magneto-electronic, thermal, and thermoelectric properties of some Co-based quaternary alloys

    Science.gov (United States)

    Bhat, Tahir Mohiuddin; Gupta, Dinesh C.

    2018-01-01

    In this study, quaternary Heusler alloys CoFeCrZ (Z = Si, As, Sb) were investigated based on the modified Becke-Johnson exchange potential. The electronic structures demonstrated that CoFeCrZ (Z = Si, As, Sb) alloys are completely spin polarized with indirect bandgap and has an integer magnetic moment according to the Slater-Pauling rule. Pugh's and Poisson's ratios showed that these materials are highly ductile with high melting temperatures. The thermal properties comprising the thermal expansion coefficient, heat capacity, and Grüneisen parameter were evaluated at various pressures from 0 to 20 GPa. The Grüneisen parameter values indicated the strong anharmonicity of the lattice vibrations that predominated in these compounds. We also studied the dependency of the thermoelectric transport properties on the temperature, i.e., the thermal conductivity and Seebeck coefficient. These alloys exhibited low lattice thermal conductivity and good Seebeck coefficients at room temperature. The half-metallic structures of these compounds with large band gaps and adequate Seebeck coefficients mean that they are suitable for use in spintronic and thermoelectric device applications.

  2. ONKALO POSE experiment. Determination of in situ thermal properties of rocks in drillholes ONK-PP340, ONK-PP346, ONK-PP398, ONK-PP399, ONK-PP405, ONK-PP411

    International Nuclear Information System (INIS)

    Korpisalo, A.; Suppala, I.; Kukkonen, I.; Koskinen, T.

    2014-12-01

    The thermal drillhole device TERO76 (for diameter 76 mm drillholes) used in this study for determining thermal properties of rocks in situ was developed at the Geological Survey of Finland for Posiva in the early 2000's. The measurement method is based on monitoring the temperature variation of a cylindrical heating source in a drillhole. The measured data can be interpreted with full numerical 3D codes as well as with an analytical infinite line source method, a 'rapid interpretation tool', which makes it possible to calculate the first estimates of thermal properties already in the field. Both methods were applied in this study. Because of the unique measurement geometry, only the thermal conductivities can accurately be estimated using the late times of heating periods (accuracy ± 2%). The cylindrical source method cannot directly give the thermal diffusivity or volumetric heat capacity at a sufficient accuracy. Thermal diffusivities are estimated by using the average specific heat capacities and densities of the rock type at the measurement point, or the laboratory results on the general diffusivity-conductivity relationship for different Olkiluoto rock types. The latter technique was applied in this study. Thermal properties were determined in four shallow drillholes (ONK-PP398, ONK-PP399, ONK-PP405, ONK-PP411) located in the ONKALO investigation niche 3 (ONK-TKU-3620) at the access tunnel chainage of 3620 m. The measurement positions (17) were strictly selected on the grounds that approximately an equal number of in situ results would be available in both veined gneiss (VGN) and pegmatitic granite (PGR). The results from the drillholes ONK-PP340 and ONK-PP346 measured in a previous project are also presented in this report. In veined gneiss, the average conductivity determined with numerical model of the present measurements is 3.49 (2.83) Wm -1 K -1 and diffusivity 1.89 x 10 -6 (1.3 10 -6 ) m 2 s -1 . The laboratory values of Olkiluoto rocks

  3. Thermal Properties of Hybrid Carbon Nanotube/Carbon Fiber Polymer

    Science.gov (United States)

    Kang, Jin Ho; Cano, Roberto J.; Luong, Hoa; Ratcliffe, James G.; Grimsley, Brian W.; Siochi, Emilie J.

    2016-01-01

    Carbon fiber reinforced polymer (CFRP) composites possess many advantages for aircraft structures over conventional aluminum alloys: light weight, higher strength- and stiffness-to-weight ratio, and low life-cycle maintenance costs. However, the relatively low thermal and electrical conductivities of CFRP composites are deficient in providing structural safety under certain operational conditions such as lightning strikes. One possible solution to these issues is to interleave carbon nanotube (CNT) sheets between conventional carbon fiber (CF) composite layers. However, the thermal and electrical properties of the orthotropic hybrid CNT/CF composites have not been fully understood. In this study, hybrid CNT/CF polymer composites were fabricated by interleaving layers of CNT sheets with Hexcel (Registered Trademark) IM7/8852 prepreg. The CNT sheets were infused with a 5% solution of a compatible epoxy resin prior to composite fabrication. Orthotropic thermal and electrical conductivities of the hybrid polymer composites were evaluated. The interleaved CNT sheets improved the in-plane thermal conductivity of the hybrid composite laminates by about 400% and the electrical conductivity by about 3 orders of magnitude.

  4. Thermal properties and corrosion resistance of organoclay/epoxy resin film

    Science.gov (United States)

    Baiquni, M.; Soegijono, B.

    2018-03-01

    Hybrid materials organoclay/epoxy resin films were prepared by varying organoclay content in epoxy resin as a matrix. The film were investigated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and thermal conductivity. TGA and FT-IR results confirmed that the melting temperature shifted to a lower point. The thermal conductivity and corrosion resistant generally increase with increasing organoclay content. The changes on these properties may due to cross link between organoclay and epoxy.

  5. Dynamic measurement of coal thermal properties and elemental composition of volatile matter during coal pyrolysis

    Directory of Open Access Journals (Sweden)

    Rohan Stanger

    2014-01-01

    Full Text Available A new technique that allows dynamic measurement of thermal properties, expansion and the elemental chemistry of the volatile matter being evolved as coal is pyrolysed is described. The thermal and other properties are measured dynamically as a function of temperature of the coal without the need for equilibration at temperature. In particular, the technique allows for continuous elemental characterisation of tars as they are evolved during pyrolysis and afterwards as a function of boiling point. The technique is demonstrated by measuring the properties of maceral concentrates from a coal. The variation in heats of reaction, thermal conductivity and expansion as a function of maceral composition is described. Combined with the elemental analysis, the results aid in the interpretation of the chemical processes contributing to the physical and thermal behaviour of the coal during pyrolysis. Potential applications in cokemaking studies are discussed.

  6. Thermal properties of Avery Island salt to 5730K and 50-MPa confining pressure

    International Nuclear Information System (INIS)

    Durham, W.B.; Abey, A.E.

    1981-01-01

    Thermal conductivity, thermal diffusivity, and thermal linear expansion were measured on two samples of Avery Island rock salt up to simultaneous temperatures and pressures of 573 0 K and 50 MPa. Thermal conductivity at room temperature measured 6.3 +- 0.6 W/mK and decreased monotonically to 3.3 +- 0.4 W/mK at 573 0 K. Thermal diffusivity decreased from 3.0 +- 0.8 x 10 -6 m 2 /s at room temperature to 1.4 +- 0.5 x 10 -6 m 2 /s at 573 0 K. Thermal linear expansivity increased from 4.8 +- 0.3 x 10 -5 K -1 at room temperature to 5.6 +- 0.3 x 10 -5 K -1 at 573 0 K. The thermal properties showed no measurable (+-5%) dependence on confining pressure from 0 to 50 MPa for any temperature tested. The thermal conductivity values were not distinguishable (+-5%) from intrinsic (single crystal) values measured by others. Diffusivity fell about 20% below intrinsic values, and linear expansivity about 20% above intrinsic values. Thermal conductivity values for Avery Island salt measured recently by Morgan are as much as 50% lower than values measured here and were probably strongly affected by sample handling prior to measurement. The pressure independence of the thermal properties measured in our study suggests that thermally-induced microfracturing is nearly nonexistent. This lack of thermal cracking is consistent with the high (cubic) symmetry of halite

  7. Alternative High Performance Polymers for Ablative Thermal Protection Systems

    Science.gov (United States)

    Boghozian, Tane; Stackpoole, Mairead; Gonzales, Greg

    2015-01-01

    Ablative thermal protection systems are commonly used as protection from the intense heat during re-entry of a space vehicle and have been used successfully on many missions including Stardust and Mars Science Laboratory both of which used PICA - a phenolic based ablator. Historically, phenolic resin has served as the ablative polymer for many TPS systems. However, it has limitations in both processing and properties such as char yield, glass transition temperature and char stability. Therefore alternative high performance polymers are being considered including cyanate ester resin, polyimide, and polybenzoxazine. Thermal and mechanical properties of these resin systems were characterized and compared with phenolic resin.

  8. Thermal properties of UO2 from density functional theory: role of strong correlations

    International Nuclear Information System (INIS)

    Panigrahi, Puspamitra; Kaur Gurpreet; Valsakumar, M.C.

    2011-01-01

    We report a study of ground state magnetic structure of Uranium-dioxide (UO 2 ) using ab initio calculations employing PAW pseudopotentials and Dudarev's version of GGA+U formalism as implemented in VASP to take into account the strong on-site Coulomb correlation among the localized Uranium-5f electrons. By choosing the value of the Hubbard parameter U eff to be 4.0 eV, we have confirmed the experimental observation that the ground state of UO 2 is an insulator with an anti-ferromagnetic (AFM) ordering. We study systematically the ground state structural, electronic, and magnetic properties of UO 2 and focus on the structure sensitive thermal properties such as specific heat, thermal expansion and comment on the calculation of thermal conductivity. (author)

  9. Fabrication, thermal properties and thermal stabilities of microencapsulated n-alkane with poly(lauryl methacrylate) as shell

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Xiaolin, E-mail: shirleyqiu2009@gmail.com [Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology, School of Mechanical Engineering, Jiangnan University, Wuxi 214122 (China); Lu, Lixin; Wang, Ju [Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology, School of Mechanical Engineering, Jiangnan University, Wuxi 214122 (China); Tang, Guoyi [Advanced Materials Institute and Clearer Production Key Laboratory, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Key Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Haidian District, Beijing 100084 (China); Song, Guolin [Advanced Materials Institute and Clearer Production Key Laboratory, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China)

    2015-11-20

    Highlights: • Microencapsulation of octadecane and paraffin by crosslinked poly(lauryl methacrylate). • Octadecane microcapsules have a melting enthalpy of about 118 J g{sup −1}. • Weight loss temperatures of the microcapsules were increased by 67 °C and 28 °C. • Phase change enthalpies decreased by around 10 wt% after 500 thermal cycles. • Foams with microcapsules can be applied for passive temperature control. - Abstract: Microencapsulation of n-octadecane or paraffin with poly(lauryl methacrylate) (PLMA) shell was performed by a suspension-like polymerization. The polymer shell was crosslinked by pentaerythritol tetraacrylate (PETRA). The surface morphologies of microcapsules were investigated by scanning electron microscopy (SEM). Phase change properties, thermal reliabilities and thermal stabilities of microcapsules were determined by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The n-octadecane microcapsule exhibits higher melting enthalpy (118.0 J g{sup −1}) and crystallization enthalpy (108.3 J g{sup −1}) compared with the paraffin microcapsule. The thermal resistant temperatures were enhanced by more than 25 °C when n-alkanes were microencapsulated by PLMA. The PCM contents of microcapsules decreased by less than 4 wt% and 6 wt% after 500 and 1000 thermal cycles, respectively. Heat-up experiments indicated that microcapsule-treated foams exhibited upgraded thermal regulation capacities. Consequently, microencapsulated n-octadecane or paraffin with PLMA as shell possesses good potentials for heat storage and thermal regulation.

  10. Influence of thermal cycling on flexural properties of composites reinforced with unidirectional silica-glass fibers.

    Science.gov (United States)

    Meriç, Gökçe; Ruyter, I Eystein

    2008-08-01

    The purpose was to investigate the effect of water storage and thermal cycling on the flexural properties of differently sized unidirectional fiber-reinforced composites (FRCs) containing different quantities of fibers. The effect of fiber orientation on the thermal expansion of FRCs as well as how the stresses in the composites can be affected was considered. An experimental polymeric base material was reinforced with silica-glass fibers. The cleaned and silanized fibers were sized with either linear PBMA-size or crosslinked PMMA-size. For the determination of flexural properties and water uptake, specimens were processed with various quantities of differently sized unidirectional fibers. Water uptake of FRC was measured. Water immersed specimens were thermally cycled for 500 and 12,000 cycles (5 degrees C/55 degrees C). Flexural properties of "dry" and wet specimens with and without thermal cycling were determined by a three-point bending test. The linear coefficients of thermal expansion (LCTE) for FRC samples with different fiber orientations were determined using a thermomechanical analyzer. Water uptake of the FRC specimens increased with a decrease in fiber content of the FRC. Flexural properties of FRCs improved with increasing fiber content, whereas the flexural properties were not influenced significantly by water and thermal cycling. Fiber orientation had different effects on LCTE of FRCs. Unidirectional FRCs had two different LCTE in longitudinal and transverse directions whereas bidirectional FRCs had similar LCTE in two directions and a higher one in the third direction. The results of the study suggest that the surface-treated unidirectional silica-glass FRC can be used for long-term clinical applications in the oral cavity.

  11. Thermal and mechanical properties of polyamide 6/compatibilizer/clay nano composites

    International Nuclear Information System (INIS)

    Agrawal, P.; Brito, G.F.; Cunha, C.T.C.; Araujo, E.M.; Melo, T.J.A.

    2010-01-01

    In this work, the thermal and mechanical properties of Polyamide 6 (PA6)/compatibilizer/clay (CL20A) nanocomposites were investigated. The nanocomposites were prepared in a counter-rotating twin screw extruder at 240 deg C and 50 rpm, and characterized by X-Ray Diffraction (XRD), Thermogravimetry (TG) and mechanical properties. XRD results showed that when the clay is mixed with PA6, the clay peak is shifted to lower 2θ angles, indicating that PA6 was intercalated between the clay platelets. For PA6/compatibilizer/clay system, the results indicated that a nanocomposite with exfoliated structure was formed. TG results showed that the thermal stability of PA6/CL20A and PA6/compatibilizer/CL20A was higher than that of neat PA6. The mechanical properties results showed that the addition of the compatibilizer to PA6/CL20A substantially increased the impact strength and decreased the stiffness. (author)

  12. THERMAL INSULATION PROPERTIES RESEARCH OF THE COMPOSITE MATERIAL WATER GLASS–GRAPHITE MICROPARTICLES

    Directory of Open Access Journals (Sweden)

    V. A. Gostev

    2014-05-01

    Full Text Available Research results for the composite material (CM water glass–graphite microparticles with high thermal stability and thermal insulation properties are given. A composition consisting of graphite (42 % by weight, water glass Na2O(SiO2n (50% by weight and the hardener - sodium silicofluoric Na2SiF6 (8% by weight. Technology of such composition receipt is suggested. Experimental samples of the CM with filler particles (graphite and a few microns in size were obtained. This is confirmed by a study of samples by X-ray diffraction and electron microscopy. The qualitative and quantitative phase analysis of the CM structure is done. Load limit values leading to the destruction of CM are identified. The character of the rupture surface is detected. Numerical values of specific heat and thermal conductivity are defined. Dependence of the specific heat capacity and thermal conductivity on temperature at monotonic heating is obtained experimentally. Studies have confirmed the increased thermal insulation properties of the proposed composition. CM with such characteristics can be recommended as a coating designed to reduce heat losses and resistant to high temperatures. Due to accessibility and low cost of its components the proposed material can be produced on an industrial scale.

  13. Thermal Properties of West Siberian Sediments in Application to Basin and Petroleum Systems Modeling

    Science.gov (United States)

    Romushkevich, Raisa; Popov, Evgeny; Popov, Yury; Chekhonin, Evgeny; Myasnikov, Artem; Kazak, Andrey; Belenkaya, Irina; Zagranovskaya, Dzhuliya

    2016-04-01

    Quality of heat flow and rock thermal property data is the crucial question in basin and petroleum system modeling. A number of significant deviations in thermal conductivity values were observed during our integral geothermal study of West Siberian platform reporting that the corrections should be carried out in basin models. The experimental data including thermal anisotropy and heterogeneity measurements were obtained along of more than 15 000 core samples and about 4 500 core plugs. The measurements were performed in 1993-2015 with the optical scanning technique within the Continental Super-Deep Drilling Program (Russia) for scientific super-deep well Tyumenskaya SG-6, parametric super-deep well Yen-Yakhinskaya, and deep well Yarudeyskaya-38 as well as for 13 oil and gas fields in the West Siberia. Variations of the thermal conductivity tensor components in parallel and perpendicular direction to the layer stratification (assessed for 2D anisotropy model of the rock studied), volumetric heat capacity and thermal anisotropy coefficient values and average values of the thermal properties were the subject of statistical analysis for the uppermost deposits aged by: T3-J2 (200-165 Ma); J2-J3 (165-150 Ma); J3 (150-145 Ma); K1 (145-136 Ma); K1 (136-125 Ma); K1-K2 (125-94 Ma); K2-Pg+Ng+Q (94-0 Ma). Uncertainties caused by deviations of thermal conductivity data from its average values were found to be as high as 45 % leading to unexpected errors in the basin heat flow determinations. Also, the essential spatial-temporal variations in the thermal rock properties in the study area is proposed to be taken into account in thermo-hydrodynamic modeling of hydrocarbon recovery with thermal methods. The research work was done with financial support of the Russian Ministry of Education and Science (unique identification number RFMEFI58114X0008).

  14. Theoretical investigation of thermophysical properties in two-temperature argon-helium thermal plasma

    International Nuclear Information System (INIS)

    Sharma, Rohit; Singh, Kuldip; Singh, Gurpreet

    2011-01-01

    The thermophysical properties of argon-helium thermal plasma have been studied in the temperature range from 5000 to 40 000 K at atmospheric pressure in local thermodynamic equilibrium and non-local thermodynamic equilibrium conditions. Two cases of thermal plasma considered are (i) ground state plasma in which all the atoms and ions are assumed to be in the ground state and (ii) excited state plasma in which atoms and ions are distributed over various possible excited states. The influence of electronic excitation and non-equilibrium parameter θ = T e /T h on thermodynamic properties (composition, degree of ionization, Debye length, enthalpy, and total specific heat) and transport properties (electrical conductivity, electron thermal conductivity, and thermal diffusion ratio) have been studied. Within the framework of Chapman-Enskog method, the higher-order contributions to transport coefficient and their convergence are studied. The influence of different molar compositions of argon-helium plasma mixture on convergence of higher-orders is investigated. Furthermore, the effect of different definitions of Debye length has also been examined for electrical conductivity and it is observed that electrical conductivity with the definition of Debye length (in which only electrons participate in screening) is less than that of the another definition (in which both the electrons and ions participate in screening) and this deviation increases with electron temperature. Finally, the effect of lowering of ionization energy is examined on electron number density, Debye length, and higher-order contribution to electrical conductivity. It is observed that the lowering of the ionization energy affects the electron transport-properties and consequently their higher-order contributions depending upon the value of the non-equilibrium parameter θ.

  15. The structure and thermal properties of plasma-sprayed beryllium for the International Thermonuclear Experimental Reactor (ITER)

    International Nuclear Information System (INIS)

    Castro, R.G.; Bartlett, A.; Elliott, K.E.; Hollis, K.J.

    1996-01-01

    Plasma spraying is being studied for in situ repair of damaged Be and W plasma facing surfaces for ITER, the next generation magnetic fusion energy device, and is also being considered for fabricating Be and W plasma-facing components for the first wall of ITER. Investigators at LANL's Beryllium Atomization and Thermal Spray Facility have concentrated on investigating the structure-property relation between as-deposited microstructures of plasma sprayed Be coatings and resulting thermal properties. In this study, the effect of initial substrate temperature on resulting thermal diffusivity of Be coatings and the thermal diffusivity at the coating/Be substrate interface (interface thermal resistance) was investigated. Results show that initial Be substrate temperatures above 600 C can improve the thermal diffusivity of the Be coatings and minimize any thermal resistance at the interface between the Be coating and Be substrate

  16. Characterization of Physical and Thermal Properties of Biofield Treated Neopentyl Glycol

    OpenAIRE

    Trivedi , Mahendra Kumar; Tallapragada , Rama Mohan; Branton , Alice; Trivedi , Dahryn; Nayak , Gopal; Mishra , Rakesh; Jana , Snehasis

    2015-01-01

    International audience; Neopentyl glycol (NPG) has been extensively used as solid-solid phase change materials (PCMs) for thermal energy storage applications. The objective of the present study was to evaluate the impact of biofield treatment on physical, spectral and thermal properties of NPG. The study was performed in two groups (control and treated). The control group remained as untreated, and treatment group was subjected to Mr. Trivedi’s biofield treatment. The control and treated NPG ...

  17. Thermal conductivity and latent heat thermal energy storage properties of LDPE/wax as a shape-stabilized composite phase change material

    International Nuclear Information System (INIS)

    Trigui, Abdelwaheb; Karkri, Mustapha; Krupa, Igor

    2014-01-01

    Highlights: • This study deals with the comparison of experimental results for different PCM composite to be used in passive solar walls. • This paper reports on the successful use of a specific experimental method in order to characterize the phase change effects. • The results have shown that most important thermal properties of these composites at the solid and liquid states. • Results indicate the thermal effectiveness of phase change material and significant amount of energy saving can be achieved. • Heat flux measurements are a very interesting experimental source of data which comes to complete the calorimetric device (DSC). - Abstract: Phase change material (PCM) composites based on low-density polyethylene (LDPE) with paraffin waxes were investigated in this study. The composites were prepared using a meltmixing method with a Brabender-Plastograph. The LDPE as the supporting matrix kept the molten waxes in compact shape during its phase transition from solid to liquid. Immiscibility of the PCMs (waxes) and the supporting matrix (LDPE) is a necessary property for effective energy storage. Therefore, this type paraffin can be used in a latent heat storage system without encapsulation. The objective of this research is to use PCM composite as integrated components in a passive solar wall. The proposed composite TROMBE wall allows daily storage of the solar energy in a building envelope and restitution in the evening, with a possible control of the air flux in a ventilated air layer. An experimental set-up was built to determine the thermal response of these composites to thermal solicitations. In addition, a DSC analysis was carried out. The results have shown that most important thermal properties of these composites at the solid and liquid states, like the “apparent” thermal conductivity, the heat storage capacity and the latent heat of fusion. Results indicate the performance of the proposed system is affected by the thermal effectiveness of

  18. Application of the specific thermal properties of Ag nanoparticles to high-resolution metal patterning

    International Nuclear Information System (INIS)

    Son, Yong; Yeo, Junyeob; Ha, Cheol Woo; Lee, Jinhwan; Hong, Sukjoon; Nam, Koo Hyun; Yang, Dong-Yol; Ko, Seung Hwan

    2012-01-01

    Metal nanoparticles exhibit specific electronic, chemical and optical properties due to the thermodynamic size effect, which cannot be observed in bulk materials. Ag NPs show size dependent melting temperature depression phenomena. In this study, the thermal sintering behavior of the self-assembled monolayer protected Ag NPs has been observed using in situ transmission electron microscopy. The thermal characteristics of the Ag NPs have also been examined with a thermogravimetric analysis, a differential scanning calorimetry and a thermal conductivity measurement. These assessments have shown that the melting of the Ag NPs starts at 150 °C, which is much lower than the melting temperature of bulk silver (960 °C). The measured thermal conductivity of the Ag NPs (0.37 W/(m K)) is also lower than that of bulk silver (429 W/(m K)). These specific thermal properties of the Ag NPs can be applied to a low-temperature and a high-resolution direct-metal patterning process.

  19. Heat experiment design to estimate temperature dependent thermal properties

    International Nuclear Information System (INIS)

    Romanovski, M

    2008-01-01

    Experimental conditions are studied to optimize transient experiments for estimating temperature dependent thermal conductivity and volumetric heat capacity. A mathematical model of a specimen is the one-dimensional heat equation with boundary conditions of the second kind. Thermal properties are assumed to vary nonlinearly with temperature. Experimental conditions refer to the thermal loading scheme, sampling times and sensor location. A numerical model of experimental configurations is studied to elicit the optimal conditions. The numerical solution of the design problem is formulated on a regularization scheme with a stabilizer minimization without a regularization parameter. An explicit design criterion is used to reveal the optimal sensor location, heating duration and flux magnitude. Results obtained indicate that even the strongly nonlinear experimental design problem admits the aggregation of its solution and has a strictly defined optimal measurement scheme. Additional region of temperature measurements with allowable identification error is revealed.

  20. KNO3/NaNO3 - Graphite materials for thermal energy storage at high temperature: Part I. - Elaboration methods and thermal properties

    International Nuclear Information System (INIS)

    Acem, Zoubir; Lopez, Jerome; Palomo Del Barrio, Elena

    2010-01-01

    Composites graphite/salt for thermal energy storage at high temperature (∼200 deg. C) have been developed and tested. As at low temperature in the past, graphite has been used to enhance the thermal conductivity of the eutectic system KNO 3 /NaNO 3 . A new elaboration method has been proposed as an alternative to graphite foams infiltration. It consists of cold-compression of a physical mixing of expanded natural graphite particles and salt powder. Two different compression routes have been investigated: uni-axial compression and isostatic compression. The first part of the paper has been devoted to the analysis of the thermal properties of these new graphite/salt composites. It is proven that cold-compression is a simple and efficient technique for improving the salt thermal conductivity. For instance, graphite amounts between 15 and 20%wt lead to apparent thermal conductivities close to 20 W/m/K (20 times greater than the thermal conductivity of the salt). Furthermore, some advantages in terms of cost and safety are expected because materials elaboration is carried out at room temperature. The second part of the paper is focused on the analyses of the phase transition properties of these graphite/salt composites materials.

  1. Structural and thermal properties of γ – irradiated Bombyx mori silk fibroin films

    Energy Technology Data Exchange (ETDEWEB)

    Madhukumar, R.; Asha, S.; Rao, B. Lakshmeesha; Shivananda, C. S.; Harish, K. V.; Sangappa, E-mail: syhalabhavi@yahoo.co.in [Department of Studies in Physics, Mangalore University, Mangalagangotri, Mangalore - 574199 (India); Sarojini, B. K. [Department of Studies in Chemistry, Mangalore University, Mangalagangotri, Mangalore - 574199 (India); Somashekar, R. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore - 570006 (India)

    2015-06-24

    The gamma radiation-induced change in structural and thermal properties of Bombyx mori silk fibroin films were investigated and have been correlated with the applied radiation doses. Irradiation of samples were carried out in dry air at room temperature using Co-60 source, and radiation doses are in the range of 0 - 300 kGy. Structural and thermal properties of the irradiated silk films were studied using X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA) and compared with unirradiated sample. Interesting results are discussed in this report.

  2. Evaluation of property tax bonus to promote solar thermal systems in Andalusia (Spain)

    International Nuclear Information System (INIS)

    Sánchez-Braza, Antonio; Pablo-Romero, María del P.

    2014-01-01

    This paper evaluates the effects of a property tax bonus to promote the installation of solar–thermal energy systems in buildings in Andalusia (southern Spain). The propensity score matching methodology is used. The treatment group consists of municipalities of Andalusia that established property tax bonuses in their municipalities in 2010. The control group consists of municipalities that did not. The response variable measures the number of new square meters of solar thermal systems installed in 2010. The analysis leads to the conclusion that municipalities that established a property tax bonus had installed, on average, 102.245 to 122.389 square meters more. These results indicate that the percentage increase in squares meters installed in municipalities which adopted the tax bonus promotion ranged from 70.74% to 98.38%. These percentages were lower for rural municipalities (49.00% to 77.06%). - Highlights: • This paper evaluates the effects of a tax bonus to promote solar–thermal energy. • We analyse the effect of this measure for 585 Andalusia municipalities. • The propensity score-matching methodology is used. • The percentage increase of square meters installed ranged from 70.74% to 98.38%. • Tax bonus was an effective tool to promote solar thermal in Andalusia

  3. Thermal and non-thermal preservation techniques of tiger nuts' beverage "horchata de chufa". Implications for food safety, nutritional and quality properties.

    Science.gov (United States)

    Roselló-Soto, Elena; Poojary, Mahesha M; Barba, Francisco J; Koubaa, Mohamed; Lorenzo, Jose M; Mañes, Jordi; Moltó, Juan Carlos

    2018-03-01

    "Horchata de chufa" is a traditional Spanish beverage produced from tiger nuts (Cyperus esculentus L.). Due to its richness in nutritional compounds, it is highly perishable and its conservation by pasteurization and/or adding preservatives is required. Although efficient, conventional thermal treatment for pasteurization induces changes in the nutritional and sensory properties. Replacing conventional pasteurization by non-thermal technologies such as pulsed electric fields, ultraviolet, and high pressure, combined with moderate temperatures (preservation of the most thermo-sensitive molecules. Accordingly, this review deals with the description of the most relevant non-thermal technologies applied to preserve "horchata" beverage in order to extend the shelf life and inactivate pathogenic microorganisms as well as to preserve the nutritional and quality properties of this food beverage. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Report on Understanding and Predicting Effects of Thermal Aging on Microstructure and Tensile Properties of Grade 91 Steel for Structural Components

    Energy Technology Data Exchange (ETDEWEB)

    Li, Meimei [Argonne National Lab. (ANL), Argonne, IL (United States); Natesan, K. [Argonne National Lab. (ANL), Argonne, IL (United States); Chen, Weiying [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-08-01

    This report provides an update on understanding and predicting the effects of long-term thermal aging on microstructure and tensile properties of G91 to corroborate the ASME Code rules in strength reduction due to elevated temperature service. The research is to support the design and long-term operation of G91 structural components in sodium-cooled fast reactors (SFRs). The report is a Level 2 deliverable in FY17 (M2AT-17AN1602017), under the Work Package AT-17AN160201, “SFR Materials Testing” performed by the Argonne National Laboratory (ANL), as part of the Advanced Reactor Technologies Program.

  5. Mechanical and thermal properties of irradiated films based on Tilapia (Oreochromis niloticus) proteins

    Energy Technology Data Exchange (ETDEWEB)

    Sabato, S.F. [Radiation Technology Center, IPEN-CNEN/SP, Av. Lineu Prestes 2242, 05508 900 Sao Paulo, SP (Brazil)], E-mail: sfsabato@ipen.br; Nakamurakare, N.; Sobral, P.J.A. [Food Engineering Department, ZEA/FZEA/USP, Av. Duque de Caxias Norte 225, 13635 900 Pirassununga, SP (Brazil)

    2007-11-15

    Proteins are considered potential material in natural films as alternative to traditional packaging. When gamma radiation is applied to protein film forming solution it resulted in an improvement in mechanical properties of whey protein films. The objective of this work was the characterization of mechanical and thermal properties of irradiated films based on muscle proteins from Nile Tilapia (Oreochromis niloticus). The films were prepared according to a casting technique with two levels of plasticizer: 25% and 45% glycerol and irradiated in electron accelerator type Radiation Dynamics, 0.550 MeV at dose range from 0 to 200 kGy. Thermal properties and mechanical properties were determined using a differential scanning calorimeter and a texture analyzer, respectively. Radiation from electron beam caused a slightly increase on its tensile strength characteristic at 100 kGy, while elongation value at this dose had no reduction.

  6. Mechanical and thermal properties of irradiated films based on Tilapia (Oreochromis niloticus) proteins

    International Nuclear Information System (INIS)

    Sabato, S.F.; Nakamurakare, N.; Sobral, P.J.A.

    2007-01-01

    Proteins are considered potential material in natural films as alternative to traditional packaging. When gamma radiation is applied to protein film forming solution it resulted in an improvement in mechanical properties of whey protein films. The objective of this work was the characterization of mechanical and thermal properties of irradiated films based on muscle proteins from Nile Tilapia (Oreochromis niloticus). The films were prepared according to a casting technique with two levels of plasticizer: 25% and 45% glycerol and irradiated in electron accelerator type Radiation Dynamics, 0.550 MeV at dose range from 0 to 200 kGy. Thermal properties and mechanical properties were determined using a differential scanning calorimeter and a texture analyzer, respectively. Radiation from electron beam caused a slightly increase on its tensile strength characteristic at 100 kGy, while elongation value at this dose had no reduction

  7. Effects of carbon content on high-temperature mechanical and thermal fatigue properties of high-boron austenitic steels

    Directory of Open Access Journals (Sweden)

    Xiang Chen

    2016-01-01

    Full Text Available High-temperature mechanical properties of high-boron austenitic steels (HBASs were studied at 850 °C using a dynamic thermal-mechanical simulation testing machine. In addition, the thermal fatigue properties of the alloys were investigated using the self-restraint Uddeholm thermal fatigue test, during which the alloy specimens were cycled between room temperature and 800°C. Stereomicroscopy and scanning electron microscopy were used to study the surface cracks and cross-sectional microstructure of the alloy specimens after the thermal fatigue tests. The effects of carbon content on the mechanical properties at room temperature and high-temperature as well as thermal fatigue properties of the HBASs were also studied. The experimental results show that increasing carbon content induces changes in the microstructure and mechanical properties of the HBASs. The boride phase within the HBAS matrix exhibits a round and smooth morphology, and they are distributed in a discrete manner. The hardness of the alloys increases from 239 (0.19wt.% C to 302 (0.29wt.% C and 312 HV (0.37wt.% C; the tensile yield strength at 850 °C increases from 165.1 to 190.3 and 197.1 MPa; and the compressive yield strength increases from 166.1 to 167.9 and 184.4 MPa. The results of the thermal fatigue tests (performed for 300 cycles from room temperature to 800 °C indicate that the degree of thermal fatigue of the HBAS with 0.29wt.% C (rating of 2–3 is superior to those of the alloys with 0.19wt.% (rating of 4–5 and 0.37wt.% (rating of 3–4 carbon. The main cause of this difference is the ready precipitation of M23(C,B6-type borocarbides in the alloys with high carbon content during thermal fatigue testing. The precipitation and aggregation of borocarbide particles at the grain boundaries result in the deterioration of the thermal fatigue properties of the alloys.

  8. Structure and Mechanical Properties of Al-Cu-Fe-X Alloys with Excellent Thermal Stability

    OpenAIRE

    Školáková, Andrea; Novák, Pavel; Mejzlíková, Lucie; Průša, Filip; Salvetr, Pavel; Vojtěch, Dalibor

    2017-01-01

    In this work, the structure and mechanical properties of innovative Al-Cu-Fe based alloys were studied. We focused on preparation and characterization of rapidly solidified and hot extruded Al-Cu-Fe, Al-Cu-Fe-Ni and Al-Cu-Fe-Cr alloys. The content of transition metals affects mechanical properties and structure. For this reason, microstructure, phase composition, hardness and thermal stability have been investigated in this study. The results showed exceptional thermal stability of these allo...

  9. Studies of the thermal properties of horn keratin by dielectric spectroscopy, thermogravimetric analysis and differential thermal analysis

    International Nuclear Information System (INIS)

    Marzec, E.; Piskunowicz, P.; Jaroszyk, F.

    2002-01-01

    The dielectric and thermal properties of horn keratin have been studied bu dielectric spectroscopy in the frequency range 10 1 -10 5 Hz, thermogravimetric analysis (TG) and different thermal analysis (DTA). Measurement of non-irradiated and g amma - irradiated keratin with doses 5, 50 kGy were performed at temperature from 22 to 260 o C. The results revealed the occurrence of phase transitions related to release of loosely bound water and bound water up to 200 o Cand the denaturation of the crystalline structure above this temperature. The influence of γ-irradiation on the thermal behaviour of keratin is significant only in the temperature range of denaturation. The decrease in the temperature of denaturation would suggest that γ-irradiation initiates main-chain degradation. (authors)

  10. Frequency selective bolometer development at Argonne National Laboratory

    Science.gov (United States)

    Datesman, Aaron; Pearson, John; Wang, Gensheng; Yefremenko, Volodymyr; Divan, Ralu; Downes, Thomas; Chang, Clarence; McMahon, Jeff; Meyer, Stephan; Carlstrom, John; Logan, Daniel; Perera, Thushara; Wilson, Grant; Novosad, Valentyn

    2008-07-01

    We discuss the development, at Argonne National Laboratory, of a four-pixel camera suitable for photometry of distant dusty galaxies located by Spitzer and SCUBA, and for study of other millimeter-wave sources such as ultra-luminous infrared galaxies, the Sunyaev-Zeldovich (SZ) effect in clusters, and galactic dust. Utilizing Frequency Selective Bolometers (FSBs) with superconducting Transition-Edge Sensors (TESs), each of the camera's four pixels is sensitive to four colors, with frequency bands centered approximately at 150, 220, 270, and 360 GHz. The current generation of these devices utilizes proximity effect superconducting bilayers of Mo/Au or Ti/Au for TESs, along with frequency selective circuitry on membranes of silicon nitride 1 cm across and 1 micron thick. The operational properties of these devices are determined by this circuitry, along with thermal control structures etched into the membranes. These etched structures do not perforate the membrane, so that the device is both comparatively robust mechanically and carefully tailored in terms of its thermal transport properties. In this paper, we report on development of the superconducting bilayer TES technology and characterization of the FSB stacks. This includes the use of new materials, the design and testing of thermal control structures, the introduction of desirable thermal properties using buried layers of crystalline silicon underneath the membrane, detector stability control, and optical and thermal test results. The scientific motivation, FSB design, FSB fabrication, and measurement results are discussed.

  11. Thermal Properties and Phonon Spectral Characterization of Synthetic Boron Phosphide for High Thermal Conductivity Applications.

    Science.gov (United States)

    Kang, Joon Sang; Wu, Huan; Hu, Yongjie

    2017-12-13

    Heat dissipation is an increasingly critical technological challenge in modern electronics and photonics as devices continue to shrink to the nanoscale. To address this challenge, high thermal conductivity materials that can efficiently dissipate heat from hot spots and improve device performance are urgently needed. Boron phosphide is a unique high thermal conductivity and refractory material with exceptional chemical inertness, hardness, and high thermal stability, which holds high promises for many practical applications. So far, however, challenges with boron phosphide synthesis and characterization have hampered the understanding of its fundamental properties and potential applications. Here, we describe a systematic thermal transport study based on a synergistic synthesis-experimental-modeling approach: we have chemically synthesized high-quality boron phosphide single crystals and measured their thermal conductivity as a record-high 460 W/mK at room temperature. Through nanoscale ballistic transport, we have, for the first time, mapped the phonon spectra of boron phosphide and experimentally measured its phonon mean free-path spectra with consideration of both natural and isotope-pure abundances. We have also measured the temperature- and size-dependent thermal conductivity and performed corresponding calculations by solving the three-dimensional and spectral-dependent phonon Boltzmann transport equation using the variance-reduced Monte Carlo method. The experimental results are in good agreement with that predicted by multiscale simulations and density functional theory, which together quantify the heat conduction through the phonon mode dependent scattering process. Our finding underscores the promise of boron phosphide as a high thermal conductivity material for a wide range of applications, including thermal management and energy regulation, and provides a detailed, microscopic-level understanding of the phonon spectra and thermal transport mechanisms of

  12. Characterization of Physical and Thermal Properties of Biofield Treated Neopentyl Glycol

    OpenAIRE

    Trivedi, Dahryn; Trivedi, Mahendra Kumar; Branton, Alice; Nayak, Gopal

    2015-01-01

    Neopentyl glycol (NPG) has been extensively used as solid-solid phase change materials (PCMs) for thermal energy storage applications. The objective of the present study was to evaluate the impact of biofield treatment on physical, spectral and thermal properties of NPG. The study was performed in two groups (control and treated). The control group remained as untreated, and treatment group was subjected to Mr. Trivedi’s biofield treatment. The control and treated NPG were characterized by X-...

  13. Improvements to the measurement of the thermal properties of phase change materials

    International Nuclear Information System (INIS)

    Kravvaritis, E D; Antonopoulos, K A; Tzivanidis, C

    2010-01-01

    Improvements are proposed to the well-known T-history method, which is widely used for thermal properties measurement of phase change materials (PCM). Our improvements refer to the experimental arrangement, to the way of measurement processing, as well as to the kind and presentation format of the final results. The proposed arrangement has a controlled indoor environment and is fully automatic, without need for staff attendance, even for repeated sets of measurements of the same or different PCM simultaneously. The proposed way of measurement processing is based on the use of thermal delay (i.e. temperature difference) between PCM and a reference fluid at any specified time and not in the use of their time delay at any specified temperature. This fundamental change leads to increased accuracy and considerable reduction of duration and labour of the measurement processing, as proved by the performed measurements of various PCM. The effective thermal capacity function as a final result is proved to be more useful than the results of the original method. The new procedure is a first step towards defining specifications for the measurement of PCM thermal properties

  14. Structural and thermal properties of nanocrystalline CuO synthesized by reactive magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Verma, M. [Department of Chemistry, IIT Roorkee, Roorkee-247667, India and Nano Science Laboratory, Institute Instrumentation Centre, IIT Roorkee, Roorkee-247667 (India); Gupta, V. K. [Department of Chemistry, IIT Roorkee, Roorkee-247667 (India); Gautam, Y. K.; Dave, V.; Chandra, R. [Nano Science Laboratory, Institute Instrumentation Centre, IIT Roorkee, Roorkee-247667 (India)

    2014-01-28

    Recent research has shown immense application of metal oxides like CuO, MgO, CaO, Al{sub 2}O{sub 3}, etc. in different areas which includes chemical warfare agents, medical drugs, magnetic storage media and solar energy transformation. Among the metal oxides, CuO nanoparticles are of special interest because of their excellent gas sensing and catalytic properties. In this paper we report structural and thermal properties of CuO synthesized by reactive magnetron DC sputtering. The synthesized nanoparticles were characterized by X-ray diffractometer. The XRD result reveals that as DC power increased from 30W to 80W, size of the CuO nanoparticles increased. The same results have been verified through TEM analysis. Thermal properties of these particles were studied using thermogravimetry.

  15. Residual Tensile Property of Plain Woven Jute Fiber/Poly(Lactic Acid) Green Composites during Thermal Cycling.

    Science.gov (United States)

    Katogi, Hideaki; Takemura, Kenichi; Akiyama, Motoki

    2016-07-14

    This study investigated the residual tensile properties of plain woven jute fiber reinforced poly(lactic acid) (PLA) during thermal cycling. Temperature ranges of thermal cycling tests were 35-45 °C and 35-55 °C. The maximum number of cycles was 10³ cycles. The quasi-static tensile tests of jute fiber, PLA, and composite were conducted after thermal cycling tests. Thermal mechanical analyses of jute fiber and PLA were conducted after thermal cycling tests. Results led to the following conclusions. For temperatures of 35-45 °C, tensile strength of composite at 10³ cycles decreased 10% compared to that of composite at 0 cycles. For temperatures of 35-55 °C, tensile strength and Young's modulus of composite at 10³ cycles decreased 15% and 10%, respectively, compared to that of composite at 0 cycles. Tensile properties and the coefficient of linear expansion of PLA and jute fiber remained almost unchanged after thermal cycling tests. From observation of a fracture surface, the length of fiber pull out in the fracture surface of composite at 10³ cycles was longer than that of composite at 0 cycles. Therefore, tensile properties of the composite during thermal cycling were decreased, probably because of the decrease of interfacial adhesion between the fiber and resin.

  16. Comparison of structural properties of thermally evaporated CdTe thin films on different substrates

    International Nuclear Information System (INIS)

    Tariq, G.H.; Anis-ur-Rehman, M.

    2011-01-01

    The direct energy band gap in the range of 1.5 eV and the high absorption coefficient (105 cm/sup -1/) makes Cadmium Telluride (CdTe) a suitable material for fabrication of thin film solar cells. Thin film solar cells based on CdTe (1 cm area) achieved efficiency of 15.6% on a laboratory scale. CdTe thin films were deposited by thermal evaporation technique under vacuum 2 X 10/sup -5/mbar on glass and stainless steel (SS) substrates. During deposition substrates temperature was kept same at 200 deg. C for all samples. The structural properties were determined by the X-ray Diffraction (XRD) patterns. All samples exhibit polycrystalline nature. Dependence of different structural parameters such as lattice parameter, micro strain, and grain size and dislocation density on thickness was studied. Also the influence of the different substrates on these parameters was investigated. The analysis showed that the preferential orientation of films was dependent on the substrate type. (author)

  17. An atlas of thermal data for biomass and other fuels

    Energy Technology Data Exchange (ETDEWEB)

    Gaur, S.; Reed, T.B. [Colorado School of Mines, Golden, CO (United States)

    1995-06-01

    Biomass is recognized as a major source of renewable energy. In order to convert biomass energy to more useful forms, it is necessary to have accurate scientific data on the thermal properties of biomass. This Atlas has been written to supply a uniform source of that information. In the last few decades Thermal analysis (TA) tools such as thermogravimetry, differential thermal analysis, thermo mechanical analysis, etc. have become more important. The data obtained from these techniques can provide useful information in terms of reaction mechanism, kinetic parameters, thermal stability, phase transformation, heat of reaction, etc. for gas-solid and gas-liquid systems. Unfortunately, there are no ASTM standards set for the collection of these types of data using TA techniques and therefore, different investigators use different conditions which suit their requirements for measuring this thermal data. As a result, the information obtained from different laboratories is not comparable. This Atlas provides the ability to compare new laboratory results with a wide variety of related data available in the literature and helps ensure consistency in using these data.

  18. Thermo-optical properties of Nd{sup 3+} doped phosphate glass determined by thermal lens and lifetime measurements

    Energy Technology Data Exchange (ETDEWEB)

    Martins, V.M. [Instituto de Física, Universidade Federal de Uberlândia, CEP38408-902 Uberlandia, Minas Gerais (Brazil); CIMAP – Centre de recherche sur les Ions, les Matériaux et la Photonique UMR 6252 CEA-CNRS-ENSICAEN-Université de Caen, 14050 Caen Cedex 4 (France); Messias, D.N., E-mail: dnmessias@infis.ufu.br [Instituto de Física, Universidade Federal de Uberlândia, CEP38408-902 Uberlandia, Minas Gerais (Brazil); Doualan, J.L.; Braud, A.; Camy, P. [CIMAP – Centre de recherche sur les Ions, les Matériaux et la Photonique UMR 6252 CEA-CNRS-ENSICAEN-Université de Caen, 14050 Caen Cedex 4 (France); Dantas, N.O. [Instituto de Física, Universidade Federal de Uberlândia, CEP38408-902 Uberlandia, Minas Gerais (Brazil); CIMAP – Centre de recherche sur les Ions, les Matériaux et la Photonique UMR 6252 CEA-CNRS-ENSICAEN-Université de Caen, 14050 Caen Cedex 4 (France); Instituto de Física de São Carlos, Universidade de São Paulo, USP, CEP 13560-970 São Carlos, SP (Brazil); Catunda, T. [Instituto de Física de São Carlos, Universidade de São Paulo, USP, CEP 13560-970 São Carlos, SP (Brazil); Pilla, V.; Andrade, A.A. [Instituto de Física, Universidade Federal de Uberlândia, CEP38408-902 Uberlandia, Minas Gerais (Brazil); and others

    2015-06-15

    In this paper the Normalized Lifetime Thermal Lens technique was applied to a set of Nd-doped phosphate samples in order to obtain its thermal and optical properties. Moreover, radiative emission properties were obtained by the Judd–Ofelt theory. The luminescence quantum efficiency obtained by both methods agreed very well, indicating that this thermal lens approach can be used in more complex systems where no radiative property is available. - Highlights: • Normalized Lifetime Thermal Lens was used to investigate Nd-doped samples. • Experimental setup and data analysis are simpler than in conventional techniques. • Luminescence quantum yield agrees with that obtained through standard techniques. • This approach, to obtain the quantum yield, can be extended to more complex systems.

  19. Effect of thermal history on mechanical properties of polyetheretherketone below the glass transition temperature

    Science.gov (United States)

    Cebe, Peggy; Chung, Shirley Y.; Hong, Su-Don

    1987-01-01

    The effect of thermal history on the tensile properties of polyetheretherketone neat resin films was investigated at different test temperatures (125, 25, and -100) using four samples: fast-quenched amorphous (Q); quenched, then crystallized at 180 C (C180); slowly cooled (for about 16 h) from the melt (SC); and air-cooled (2-3 h) from the melt (AC). It was found that thermal history significantly affects the tensile properties of the material below the glass transition. Fast quenched amorphous films were most tough, could be drawn to greatest strain before rupture, and undergo densification during necking; at the test temperature of -100 C, these films had the best ultimate mechanical properties. At higher temperatures, the semicrystalline films AC and C180 had properties that compared favorably with the Q films. The SC films exhibited poor mechanical properties at all test temperatures.

  20. Methods of PCM microcapsules application and the thermal properties of modified knitted fabric

    Energy Technology Data Exchange (ETDEWEB)

    Nejman, Alicja, E-mail: anejman@iw.lodz.pl [Textile Research Institute, Scientific Department of Unconventional Technologies and Textiles, 5/15 Brzezinska St., 92-103 Lodz (Poland); Cieślak, Małgorzata [Textile Research Institute, Scientific Department of Unconventional Technologies and Textiles, 5/15 Brzezinska St., 92-103 Lodz (Poland); Gajdzicki, Bogumił [Textile Research Institute, Scientific Department of Textile Chemistry and Products Modification, 5/15 Brzezinska St., 92-103 Lodz (Poland); Goetzendorf-Grabowska, Bogna; Karaszewska, Agnieszka [Textile Research Institute, Scientific Department of Unconventional Technologies and Textiles, 5/15 Brzezinska St., 92-103 Lodz (Poland)

    2014-08-10

    Highlights: • We applied microcapsules containing n-octadecane for the modification of knitted fabric. • We used printing, coating and padding techniques for the application of microcapsules. • M-PCM application methods allow to regulate the thermal properties of textiles. • M-PCM application methods allow to regulate the air permeability properties of textiles. - Abstract: The aim of the study is to analyze the impact of application methods of microcapsules containing n-octadecane as phase change materials (M-PCM) on the thermal properties and air permeability of modified textile fabric. Polyester knitted fabric, printing, coating and padding methods and polymer pastes with 20 wt.% of M-PCM were used. For the assessment of modification effects the differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were used. DSC analysis showed that the highest enthalpy of phase transitions has printed fabric and the lowest padded fabric. The widest range of phase transitions temperatures was observed for printed fabric, slightly narrower for coated fabric and the narrowest for padded fabric. SEM analysis showed differences in the morphology of modified fabrics depending on incorporation techniques, which are compatible with differences in air permeability results. M-PCM application techniques allow to regulate the thermal and air permeability properties of fabric.

  1. Methods of PCM microcapsules application and the thermal properties of modified knitted fabric

    International Nuclear Information System (INIS)

    Nejman, Alicja; Cieślak, Małgorzata; Gajdzicki, Bogumił; Goetzendorf-Grabowska, Bogna; Karaszewska, Agnieszka

    2014-01-01

    Highlights: • We applied microcapsules containing n-octadecane for the modification of knitted fabric. • We used printing, coating and padding techniques for the application of microcapsules. • M-PCM application methods allow to regulate the thermal properties of textiles. • M-PCM application methods allow to regulate the air permeability properties of textiles. - Abstract: The aim of the study is to analyze the impact of application methods of microcapsules containing n-octadecane as phase change materials (M-PCM) on the thermal properties and air permeability of modified textile fabric. Polyester knitted fabric, printing, coating and padding methods and polymer pastes with 20 wt.% of M-PCM were used. For the assessment of modification effects the differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were used. DSC analysis showed that the highest enthalpy of phase transitions has printed fabric and the lowest padded fabric. The widest range of phase transitions temperatures was observed for printed fabric, slightly narrower for coated fabric and the narrowest for padded fabric. SEM analysis showed differences in the morphology of modified fabrics depending on incorporation techniques, which are compatible with differences in air permeability results. M-PCM application techniques allow to regulate the thermal and air permeability properties of fabric

  2. Synthesis report on thermally driven coupled processes

    International Nuclear Information System (INIS)

    Hardin, E.L.

    1997-01-01

    The main purpose of this report is to document observations and data on thermally coupled processes for conditions that are expected to occur within and around a repository at Yucca Mountain. Some attempt is made to summarize values of properties (e.g., thermal properties, hydrologic properties) that can be measured in the laboratory on intact samples of the rock matrix. Variation of these properties with temperature, or with conditions likely to be encountered at elevated temperature in the host rock, is of particular interest. However, the main emphasis of this report is on direct observation of thermally coupled processes at various scales. Direct phenomenological observations are vitally important in developing and testing conceptual models. If the mathematical implementation of a conceptual model predicts a consequence that is not observed, either (1) the parameters or the boundary conditions used in the calculation are incorrect or (2) the conceptual basis of the model does not fit the experiment; in either case, the model must be revised. For example, the effective continuum model that has been used in thermohydrology studies combines matrix and fracture flow in a way that is equivalent to an assumption that water is imbibed instantaneously from fractures into adjacent, partially saturated matrix. Based on this approximation, the continuum-flow response that is analogous to fracture flow will not occur until the effective continuum is almost completely saturated. This approximation is not entirely consistent with some of the experimental data presented in this report. This report documents laboratory work and field studies undertaken in FY96 and FY97 to investigate thermally coupled processes such as heat pipes and fracture-matrix coupling. In addition, relevant activities from past years, and work undertaken outside the Yucca Mountain project are summarized and discussed. Natural and artificial analogs are also discussed to provide a convenient source of

  3. Phonon and thermal properties of exfoliated TaSe2 thin films

    International Nuclear Information System (INIS)

    Yan, Z.; Jiang, C.; Renteria, J.; Pope, T. R.; Tsang, C. F.; Stickney, J. L.; Salguero, T. T.; Goli, P.; Balandin, A. A.

    2013-01-01

    We report on the phonon and thermal properties of thin films of tantalum diselenide (2H-TaSe 2 ) obtained via the “graphene-like” mechanical exfoliation of crystals grown by chemical vapor transport. The ratio of the intensities of the Raman peak from the Si substrate and the E 2g peak of TaSe 2 presents a convenient metric for quantifying film thickness. The temperature coefficients for two main Raman peaks, A 1g and E 2g , are −0.013 and −0.0097 cm −1 / o C, respectively. The Raman optothermal measurements indicate that the room temperature thermal conductivity in these films decreases from its bulk value of ∼16 W/mK to ∼9 W/mK in 45-nm thick films. The measurement of electrical resistivity of the field-effect devices with TaSe 2 channels shows that heat conduction is dominated by acoustic phonons in these van der Waals films. The scaling of thermal conductivity with the film thickness suggests that the phonon scattering from the film boundaries is substantial despite the sharp interfaces of the mechanically cleaved samples. These results are important for understanding the thermal properties of thin films exfoliated from TaSe 2 and other metal dichalcogenides, as well as for evaluating self-heating effects in devices made from such materials

  4. Phonon and thermal properties of exfoliated TaSe2 thin films

    Science.gov (United States)

    Yan, Z.; Jiang, C.; Pope, T. R.; Tsang, C. F.; Stickney, J. L.; Goli, P.; Renteria, J.; Salguero, T. T.; Balandin, A. A.

    2013-11-01

    We report on the phonon and thermal properties of thin films of tantalum diselenide (2H-TaSe2) obtained via the "graphene-like" mechanical exfoliation of crystals grown by chemical vapor transport. The ratio of the intensities of the Raman peak from the Si substrate and the E2g peak of TaSe2 presents a convenient metric for quantifying film thickness. The temperature coefficients for two main Raman peaks, A1g and E2g, are -0.013 and -0.0097 cm-1/oC, respectively. The Raman optothermal measurements indicate that the room temperature thermal conductivity in these films decreases from its bulk value of ˜16 W/mK to ˜9 W/mK in 45-nm thick films. The measurement of electrical resistivity of the field-effect devices with TaSe2 channels shows that heat conduction is dominated by acoustic phonons in these van der Waals films. The scaling of thermal conductivity with the film thickness suggests that the phonon scattering from the film boundaries is substantial despite the sharp interfaces of the mechanically cleaved samples. These results are important for understanding the thermal properties of thin films exfoliated from TaSe2 and other metal dichalcogenides, as well as for evaluating self-heating effects in devices made from such materials.

  5. The thermal properties of the subsurface – key parameters for geothermal energy utilization

    DEFF Research Database (Denmark)

    Norden, Ben; Bording, Thue Sylvester; Balling, N.

    Often the investigation of petrophysical properties is far behind the capabilities of sophisticated modelling techniques applied in basin and geothermal modelling and for which these data serve as an input. Therefore, more in-depth investigations especially of thermal properties are requested. We...

  6. Numerical Investigation of Thermal and Thermo-mechanical Effective Properties for Short Fibre Reinforced Composite

    Science.gov (United States)

    Ioannou, Ioannis; Hodzic, Alma; Gitman, Inna M.

    2017-10-01

    This study aims to investigate the thermal conductivity and the linear coefficient of thermal expansion for short fibre reinforced composites. The study combines numerical and statistical analyses in order to primarily examine the representative size and the effective properties of the volume element. Effects of various micromechanical parameters, such as fibre's aspect ratio and fibre's orientation, on the minimum representative size are discussed. The numerically acquired effective properties, obtained for the representative size, are presented and compared with analytical models.

  7. Effect of cooking time on the physical, chemical and thermal properties of acha seeds

    Directory of Open Access Journals (Sweden)

    Akeem O. Raji

    2017-10-01

    Full Text Available Acha is a less utilized cereal grain in Africa. Scaling up of the processing technology of acha seeds is desirable if accurate information on effect of processing on its properties is available. This study investigated the effect of cooking duration on the chemical and physical properties of acha seeds. Cooking times (2.5, 5, 7.5 and 10 minutes at 100oC were used. The volume, length, breadth, thickness, porosity, density, sphericity, aspect ratio, specific heat capacity, thermal conductivity, thermal diffusivity, moisture, protein, fat, ash, crude fibre and carbohydrate were determined using standard methods. Data were analysed using ANOVA at p = 0.05. The results obtained revealed that varietal difference had a significant effect on volume, length, breadth, thickness, true density, bulk density, porosity, sphericity and aspect ratio. The moisture content, ash, protein, crude fibre, fat, carbohydrate, specific heat capacity, thermal conductivity and thermal diffusivity varied from 8.80 - 56.17 %, 0.32 - 1.87%, 1.92 - 11.50%, 0.29 - 1.58%, 0.32 - 2.81%, 40.94 - 76.26%, 1.66 -2.97 kJkg-1K-1, 0.26 -0.43 Wm-1K-1 and 0.85 x 10-7 - 1.17 x 10-7 ms-2 respectively, as significantly influenced by cooking time. Cooking for 7.5 minutes was appropriate using the moisture uptakes and thermal properties as criteria. 

  8. Role of thermo-physical properties on design and development of thermal plasma devices

    International Nuclear Information System (INIS)

    Ghorui, S.

    2014-01-01

    Thermal plasma devices find wide application in variety of technological areas like cutting, welding, spray coating, waste management, material processing, chemical reduction, nano-synthesis, novel material synthesis etc. Highly non-linear behavior of the plasma properties coupled with inherent instabilities, extremely high temperature, high gradients in thermal, and flow field, presence of thermal and chemical non-equilibrium make design and development of the plasma generating devices a challenging task as power levels of the devices increase

  9. Structural, electronic and thermal properties of super hard ternary boride, WAlB

    Science.gov (United States)

    Rajpoot, Priyanka; Rastogi, Anugya; Verma, U. P.

    2018-04-01

    A first principle study of the structural, electronic and thermal properties of Tungsten Aluminum Boride (WAlB) using full-potential linearized augmented plane wave (FP-LAPW) in the frame work of density function theory (DFT) have been calculated. The calculated equilibrium structural parameters are in excellent agreement with available experimental results. The calculated electronic band structure reveals that WAlB is metallic in nature. The quasi-harmonic Debye model is applied to study of the temperature and pressure effect on volume, Debye temperature, thermal expansion coefficient and specific heat at constant volume and constant pressure. To the best of our knowledge theoretical investigation of these properties of WAlB is reported for the first time.

  10. Impact of isotopic disorders on thermal transport properties of nanotubes and nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Tao [State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871 (China); Kang, Wei [HEDPS, Center for Applied Physics and Technology, College of Engineering, Peking University, Beijing 100871 (China); Wang, Jianxiang, E-mail: jxwang@pku.edu.cn [State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871 (China); HEDPS, Center for Applied Physics and Technology, College of Engineering, Peking University, Beijing 100871 (China)

    2015-01-21

    We present a one-dimensional lattice model to describe thermal transport in isotopically doped nanotubes and nanowires. The thermal conductivities thus predicted, as a function of isotopic concentration, agree well with recent experiments and other simulations. Our results display that for any given concentration of isotopic atoms in a lattice without sharp atomic interfaces, the maximum thermal conductivity is attained when isotopic atoms are placed regularly with an equal space, whereas the minimum is achieved when they are randomly inserted with a uniform distribution. Non-uniformity of disorder can further tune the thermal conductivity between the two values. Moreover, the dependence of the thermal conductivity on the nanoscale feature size becomes weak at low temperature when disorder exists. In addition, when self-consistent thermal reservoirs are included to describe diffusive nanomaterials, the thermal conductivities predicted by our model are in line with the results of macroscopic theories with an interfacial effect. Our results suggest that the disorder provides an additional freedom to tune the thermal properties of nanomaterials in many technological applications including nanoelectronics, solid-state lighting, energy conservation, and conversion.

  11. Impact of isotopic disorders on thermal transport properties of nanotubes and nanowires

    International Nuclear Information System (INIS)

    Sun, Tao; Kang, Wei; Wang, Jianxiang

    2015-01-01

    We present a one-dimensional lattice model to describe thermal transport in isotopically doped nanotubes and nanowires. The thermal conductivities thus predicted, as a function of isotopic concentration, agree well with recent experiments and other simulations. Our results display that for any given concentration of isotopic atoms in a lattice without sharp atomic interfaces, the maximum thermal conductivity is attained when isotopic atoms are placed regularly with an equal space, whereas the minimum is achieved when they are randomly inserted with a uniform distribution. Non-uniformity of disorder can further tune the thermal conductivity between the two values. Moreover, the dependence of the thermal conductivity on the nanoscale feature size becomes weak at low temperature when disorder exists. In addition, when self-consistent thermal reservoirs are included to describe diffusive nanomaterials, the thermal conductivities predicted by our model are in line with the results of macroscopic theories with an interfacial effect. Our results suggest that the disorder provides an additional freedom to tune the thermal properties of nanomaterials in many technological applications including nanoelectronics, solid-state lighting, energy conservation, and conversion

  12. Thermal limits of wild and laboratory strains of two African malaria vector species, Anopheles arabiensis and Anopheles funestus

    Directory of Open Access Journals (Sweden)

    Lyons Candice L

    2012-07-01

    Full Text Available Abstract Background Malaria affects large parts of the developing world and is responsible for almost 800,000 deaths annually. As climates change, concerns have arisen as to how this vector-borne disease will be impacted by changing rainfall patterns and warming temperatures. Despite the importance and controversy surrounding the impact of climate change on the potential spread of this disease, little information exists on the tolerances of several of the vector species themselves. Methods Using a ramping protocol (to assess critical thermal limits - CT and plunge protocol (to assess lethal temperature limits - LT information on the thermal tolerance of two of Africa’s important malaria vectors, Anopheles arabiensis and Anopheles funestus was collected. The effects of age, thermal acclimation treatment, sex and strain (laboratory versus wild adults were investigated for CT determinations for each species. The effects of age and sex for adults and life stage (larvae, pupae, adults were investigated for LT determinations. Results In both species, females are more tolerant to low and high temperatures than males; larvae and pupae have higher upper lethal limits than do adults. Thermal acclimation of adults has large effects in some instances but small effects in others. Younger adults tend to be more tolerant of low or high temperatures than older age groups. Long-standing laboratory colonies are sufficiently similar in thermal tolerance to field-collected animals to provide reasonable surrogates when making inferences about wild population responses. Differences between these two vectors in their thermal tolerances, especially in larvae and pupae, are plausibly a consequence of different habitat utilization. Conclusions Limited plasticity is characteristic of the adults of these vector species relative to others examined to date, suggesting limited scope for within-generation change in thermal tolerance. These findings and the greater tolerance

  13. Protocol for Measuring the Thermal Properties of a Supercooled Synthetic Sand-water-gas-methane Hydrate Sample.

    Science.gov (United States)

    Muraoka, Michihiro; Susuki, Naoko; Yamaguchi, Hiroko; Tsuji, Tomoya; Yamamoto, Yoshitaka

    2016-03-21

    Methane hydrates (MHs) are present in large amounts in the ocean floor and permafrost regions. Methane and hydrogen hydrates are being studied as future energy resources and energy storage media. To develop a method for gas production from natural MH-bearing sediments and hydrate-based technologies, it is imperative to understand the thermal properties of gas hydrates. The thermal properties' measurements of samples comprising sand, water, methane, and MH are difficult because the melting heat of MH may affect the measurements. To solve this problem, we performed thermal properties' measurements at supercooled conditions during MH formation. The measurement protocol, calculation method of the saturation change, and tips for thermal constants' analysis of the sample using transient plane source techniques are described here. The effect of the formation heat of MH on measurement is very small because the gas hydrate formation rate is very slow. This measurement method can be applied to the thermal properties of the gas hydrate-water-guest gas system, which contains hydrogen, CO2, and ozone hydrates, because the characteristic low formation rate of gas hydrate is not unique to MH. The key point of this method is the low rate of phase transition of the target material. Hence, this method may be applied to other materials having low phase-transition rates.

  14. Thermal and hydraulic properties of the concrete used in the ILW repository of El Cabril (Spain). Preliminary laboratory tests

    International Nuclear Information System (INIS)

    Villar, Maria Victoria

    2012-01-01

    This work is a contribution to the understanding of the behaviour of concrete barriers in surface (low and intermediate-level) waste disposal facilities, in particular in the Spanish disposal facility of El Cabril, where the waste containers are placed inside concrete cells. The durability of concrete and its mechanical properties are intrinsically bound to moisture transport effects, especially when it is subjected to repeated wetting and drying regimes, and that is why a detailed thermo-hydraulic characterisation is necessary to model its behaviour. The concrete used in this experimental work has a characteristic strength of 350 kp/cm 2 and uses ordinary Portland cement, resistant to sulphates and seawater, with a water/cement ratio of 0.43. Its average pore size is 0.03 micrometer. In addition to the determination of the thermal conductivity of concrete as a function of water content, a hydraulic characterisation - including determination of saturated permeability, permeability to gas for different degrees of saturation and water retention curves - has been performed

  15. Research on the Properties of Thermal Sprayed Ni-Cr-Si-Fe-B Coatings

    Directory of Open Access Journals (Sweden)

    Raimonda Lukauskaitė

    2012-12-01

    Full Text Available The article deals with the flame sprayed Ni-Cr-Si-Fe-B coating on aluminum alloy substrates. Before the thermal spraying process, aluminum samples were modified applying chemical, mechanical and thermal processing pre-treatment methods. The main aluminum surface treatment was removing an oxide layer from the surface and improving the exploitation properties of nickel-based coatings. The work involved coating microstructure, porosity, adhesion and microhardness tests. The dependence of the estimated exploitation properties of flame spray coatings on aluminum surface preparation methods and technological parameters of spraying has been established.Article in Lithuanian

  16. Research on the Properties of Thermal Sprayed Ni-Cr-Si-Fe-B Coatings

    Directory of Open Access Journals (Sweden)

    Raimonda Lukauskaitė

    2013-02-01

    Full Text Available The article deals with the flame sprayed Ni-Cr-Si-Fe-B coating on aluminum alloy substrates. Before the thermal spraying process, aluminum samples were modified applying chemical, mechanical and thermal processing pre-treatment methods. The main aluminum surface treatment was removing an oxide layer from the surface and improving the exploitation properties of nickel-based coatings. The work involved coating microstructure, porosity, adhesion and microhardness tests. The dependence of the estimated exploitation properties of flame spray coatings on aluminum surface preparation methods and technological parameters of spraying has been established.Article in Lithuanian

  17. Thermal properties of zirconium diboride -- transition metal boride solid solutions

    Science.gov (United States)

    McClane, Devon Lee

    This research focuses on the thermal properties of zirconium diboride (ZrB2) based ceramics. The overall goal was to improve the understanding of how different transition metal (TM) additives influence thermal transport in ZrB2. To achieve this, ZrB2 with 0.5 wt% carbon, and 3 mol% of individual transition metal borides, was densified by hot-press sintering. The transition metals that were investigated were: Y, Ti, Hf, V, Nb, Ta, Cr, Mo, W, and Re. The room temperature thermal diffusivities of the compositions ranged from 0.331 cm2/s for nominally pure ZrB2 to 0.105 cm2/s for (Zr,Cr)B2 and converged around 0.155cm2/s at higher temperatures for all compositions. Thermal conductivities were calculated from the diffusivities, using temperature-dependent values for density and heat capacity. The electron contribution to thermal conductivity was calculated from measured electrical resistivity according to the Wiedemann-Franz law. The phonon contribution to thermal conductivity was calculated by subtracting the electron contribution from the total thermal conductivity. Rietveld refinement of x-ray diffraction data was used to determine the lattice parameters of the compositions. The decrease in thermal conductivity for individual additives correlated directly to the metallic radius of the additive. Additional strain appeared to exist for additives when the stable TM boride for that metal had different crystal symmetries than ZrB2. This research provided insight into how additives and impurities affect thermal transport in ZrB2. The research potentially offers a basis for future modeling of thermal conductivity in ultra-high temperature ceramics based on the correlation between metallic radius and the decrease in thermal conductivity.

  18. Photon-induced Processing of Interstellar Ices in the Laboratory. Focus on Their Non-thermal Desorption.

    Science.gov (United States)

    Martin-Domenech, Rafael; Munoz Caro, Guillermo; Cruz-Diaz, Gustavo A.; Oberg, Karin I.

    2018-06-01

    Some of the processes that take place in the interstellar medium (ISM)can be simulated in laboratories on Earth under astrophysically relevant conditions. For example, the energetic processing of the ice mantles that accrete on top of dust grains in the coldest regions of the ISM, leading to the production of new species and their desorption to the gas phase. In particular, observation of complex organic molecules (COMs) in cold interstellar environments stress the need for not only a solid state formation but also for non-thermal desorption mechanisms that can account for the observed abundances in regions where thermal desorption is inhibited. Laboratory Astrophysics can be used to test different non-thermal desorption processes and extract yields than can be extrapolated to the astrophysical scenario with theoretical models. 0th generation COMs like CH3OH and H2CO can be formed at very low temperatures. In this talk, we present laboratory simulations of the UV photoprocessing of a binary ice mixture composed by water (the main component of astrophysical ices) and methane. Formation of CO, CO2, CH3OH and H2CO was confirmed by IR spectroscopy and subsequent TPD. At the same time, photodesorption of CO and H2CO was detected by means of a Quadrupole Mass Spectrometer, with yields on the order of 10-4 and 10-5 molecules per incident photon, respectively. In general, photodesorption can take place through a direct mechanism, where the absorbing molecule (or its photofragments) are desorbed; or through an indirect mechanism where the absorbed energy is transferred to a surface molecule which is the one finally desorbing. In the case of photoproducts, the evolution of the photodesorption yield gives information on the photodesorption mechanism: a constant photodesorption yield is observed when the photoproducts are desorbed right after their formation; while an increasing yield is measured when the photoproducts are desorbed later after energy transfer from another

  19. Thermal, Thermophysical, and Compositional Properties of the Moon Revealed by the Diviner Lunar Radiometer

    Science.gov (United States)

    Greenhagen, B. T.; Paige, D. A.

    2012-01-01

    The Diviner Lunar Radiometer is the first multispectral thermal instrument to globally map the surface of the Moon. After over three years in operation, this unprecedented dataset has revealed the extreme nature of the Moon's thermal environment, thermophysical properties, and surface composition.

  20. Enhanced thermal properties of novel shape-stabilized PEG composite phase change materials with radial mesoporous silica sphere for thermal energy storage.

    Science.gov (United States)

    Min, Xin; Fang, Minghao; Huang, Zhaohui; Liu, Yan'gai; Huang, Yaoting; Wen, Ruilong; Qian, Tingting; Wu, Xiaowen

    2015-08-11

    Radial mesoporous silica (RMS) sphere was tailor-made for further applications in producing shape-stabilized composite phase change materials (ss-CPCMs) through a facile self-assembly process using CTAB as the main template and TEOS as SiO2 precursor. Novel ss-CPCMs composed of polyethylene glycol (PEG) and RMS were prepared through vacuum impregnating method. Various techniques were employed to characterize the structural and thermal properties of the ss-CPCMs. The DSC results indicated that the PEG/RMS ss-CPCM was a promising candidate for building thermal energy storage applications due to its large latent heat, suitable phase change temperature, good thermal reliability, as well as the excellent chemical compatibility and thermal stability. Importantly, the possible formation mechanisms of both RMS sphere and PEG/RMS composite have also been proposed. The results also indicated that the properties of the PEG/RMS ss-CPCMs are influenced by the adsorption limitation of the PEG molecule from RMS sphere with mesoporous structure and the effect of RMS, as the impurities, on the perfect crystallization of PEG.

  1. Estimation of soil profile properties using field and laboratory VNIR spectroscopy

    Science.gov (United States)

    Diffuse reflectance spectroscopy (DRS) soil sensors have the potential to provide rapid, high-resolution estimation of multiple soil properties. Although many studies have focused on laboratory-based visible and near-infrared (VNIR) spectroscopy of dried soil samples, previous work has demonstrated ...

  2. Mechanical, thermal and friction properties of rice bran carbon/nitrile rubber composites: Influence of particle size and loading

    International Nuclear Information System (INIS)

    Li, Mei-Chun; Zhang, Yinhang; Cho, Ur Ryong

    2014-01-01

    Highlights: • A novel rice bran carbon (RBC) is used to reinforce nitrile rubber. • We study the effect of RBC particle size on the performances of nitrile rubber. • We study the effect of RBC loading on the performances of nitrile rubber. • The addition of RBC improves the mechanical properties of nitrile rubber. • The addition of RBC improves the anti-skid properties of nitrile rubber. - Abstract: Four types of rice bran carbon (RBC) with different particle sizes were compounded with nitrile rubber (NBR) in a laboratory size two-roll miller. The obtained RBC/NBR composites were characterized using Field Emission Scanning Electron Microscopy (FE-SEM) and tensile tests. Experimental results showed the RBC with lowest particle size exhibited best dispersion state and superior reinforcement ability. Then, we investigated the influence of RBC loading on the morphology, vulcanization characteristics, mechanical, thermal and friction properties of NBR composites. Experimental results indicated that the incorporation of RBC resulted in higher torque values, longer curing time, but shorter scorch time. The addition of RBC remarkably improved the mechanical properties of NBR composites. However, when the RBC loading exceeded 60 phr, the improvement in the tensile strength was not significant due to the poor dispersion state and weak interfacial bonding between RBC and NBR matrix, which were confirmed by Mooney–Rivlin stress–strain curves and FE-SEM observations. The thermal stabilities of RBC/NBR composites were largely improved as the loading of RBC increased. Friction tests revealed that under a certain concentration, the presence of RBC increased the static friction coefficient of NBR composites, suggesting the anti-skid role of RBC in the NBR composites. The overall results demonstrated that RBC could act as ideal filler for NBR composites providing both economic and environmental advantages

  3. Investigations on the effect of creep stress on the thermal properties of metallic materials

    International Nuclear Information System (INIS)

    Radtke, U.; Crostack, H.A.; Winschuh, E.

    1995-01-01

    Using thermal wave analysis with front side infrared detection on sample material damaged by creep, one examines whether the creep stress has an effect on the thermal material properties and to what effect this can be used to estimate the remaining service life. (orig.) [de

  4. Local Thermal Insulating Materials For Thermal Energy Storage ...

    African Journals Online (AJOL)

    Thermal insulation is one of the most important components of a thermal energy storage system. In this paper the thermal properties of selected potential local materials which can be used for high temperature insulation are presented. Thermal properties of seven different samples were measured. Samples consisted of: ...

  5. A novel test method for measuring the thermal properties of clothing ensembles under dynamic conditions

    International Nuclear Information System (INIS)

    Wan, X; Fan, J

    2008-01-01

    The dynamic thermal properties of clothing ensembles are important to thermal transient comfort, but have so far not been properly quantified. In this paper, a novel test procedure and new index based on measurements on the sweating fabric manikin-Walter are proposed to quantify and measure the dynamic thermal properties of clothing ensembles. Experiments showed that the new index is correlated to the changing rate of the body temperature of the wearer, which is an important indicator of thermal transient comfort. Clothing ensembles having higher values of the index means the wearer will have a faster changing rate of body temperature and shorter duration before approaching a dangerous thermo-physiological state, when he changes from 'resting' to 'exercising' mode. Clothing should therefore be designed to reduce the value of the index

  6. Thermal properties and continuous-wave laser performance of Yb:LuVO4 crystal

    Science.gov (United States)

    Cheng, Y.; Zhang, H. J.; Yu, Y. G.; Wang, J. Y.; Tao, X. T.; Liu, J. H.; Petrov, V.; Ling, Z. C.; Xia, H. R.; Jiang, M. H.

    2007-03-01

    A laser crystal of Yb:LuVO4 with high optical quality was grown by the Czochralski technique. Its thermal properties including specific heat, thermal expansion coefficients, and thermal conductivities along the a- and c-axis have been measured for the first time. Continuous-wave laser output up to 3.5 W at 1031 nm was obtained at room temperature through end-pumping by a high-power diode laser. The corresponding optical conversion efficiency was 43% and the slope efficiency was 72%.

  7. Thermal-mechanical properties of a graphitic-nanofibers reinforced epoxy.

    Science.gov (United States)

    Salehi-Khojin, Amin; Jana, Soumen; Zhong, Wei-Hong

    2007-03-01

    We previously developed a series of reactive graphitic nanofibers (r-GNFs) reinforced epoxy (nano-epoxy) as composite matrices, which have shown good wetting and adhesion properties with continuous fiber. In this work, the thermal-mechanical properties of the nano-epoxy system containing EponTM Resin 828 and Epi-cure Curing Agent W were characterized. Results from three-point bending tests showed that the flexural strength and flexural modulus of this system with 0.30 wt% of reactive nanofibers were increased by 16%, and 21% respectively, over pure epoxy. Fracture toughness increased by ca. 40% for specimens with 0.50 wt% of r-GNFs. By dynamic mechanical analysis (DMA) test, specimens with 0.30 wt% of r-GNFs showed a significant increase in storage modulus E' (by ca. 122%) and loss modulus E" (by ca. 111%) with respect to that of pure epoxy. Also thermo-dilatometry analysis (TDA) was used to measure dimensional change of specimens as a function of temperature, and then, coefficients of thermal expansion (CTE) before and after glass transition temperature (Tg) were obtained. Results implied that nano-epoxy materials had good dimensional stability and reduced CTE values when compared to those of pure epoxy.

  8. Laboratory Measurements of Optical Properties of Micron Size Individual Dust Grains

    Science.gov (United States)

    Abbas, M. M.; Craven, P. D.; Spann, J. F.; Tankosic, D.; LeClair, A.; Witherow, W. K.; Camata, R.; Gerakines, P.

    2003-01-01

    A laboratory program is being developed at NASA Marshall Space Flight Center for experimental determination of the optical and physical properties individual dust grains in simulated astrophysical environments. The experimental setup is based on an electrodynamic balance that permits levitation of single 0.1 - 10 micron radii dust grains in a cavity evacuated to pressures of approx. 10(exp -6) torr. The experimental apparatus is equipped with observational ports for measurements in the UV, visible, and infrared spectral regions. A cryogenic facility for cooling the particles to temperature of approx. 10-50K is being installed. The current and the planned measurements include: dust charging processes, photoelectric emissions and yields with UV irradiation, radiation pressure measurements, infrared absorption and scattering properties, and condensation processes, involving the analogs of cosmic dust grains. Selected results based on photoemissions, radiation pressure, and other laboratory measurements will be presented.

  9. Residual Tensile Property of Plain Woven Jute Fiber/Poly(Lactic Acid Green Composites during Thermal Cycling

    Directory of Open Access Journals (Sweden)

    Hideaki Katogi

    2016-07-01

    Full Text Available This study investigated the residual tensile properties of plain woven jute fiber reinforced poly(lactic acid (PLA during thermal cycling. Temperature ranges of thermal cycling tests were 35–45 °C and 35–55 °C. The maximum number of cycles was 103 cycles. The quasi-static tensile tests of jute fiber, PLA, and composite were conducted after thermal cycling tests. Thermal mechanical analyses of jute fiber and PLA were conducted after thermal cycling tests. Results led to the following conclusions. For temperatures of 35–45 °C, tensile strength of composite at 103 cycles decreased 10% compared to that of composite at 0 cycles. For temperatures of 35–55 °C, tensile strength and Young’s modulus of composite at 103 cycles decreased 15% and 10%, respectively, compared to that of composite at 0 cycles. Tensile properties and the coefficient of linear expansion of PLA and jute fiber remained almost unchanged after thermal cycling tests. From observation of a fracture surface, the length of fiber pull out in the fracture surface of composite at 103 cycles was longer than that of composite at 0 cycles. Therefore, tensile properties of the composite during thermal cycling were decreased, probably because of the decrease of interfacial adhesion between the fiber and resin.

  10. Highlighting High Performance: National Renewable Energy Laboratory's Thermal Test Facility, Golden, Colorado. Office of Building Technology State and Community Programs (BTS) Brochure

    International Nuclear Information System (INIS)

    Burgert, S.

    2001-01-01

    The National Renewable Energy Laboratory's Thermal Test Facility in Golden, Colorado, was designed using a whole-building approach-looking at the way the building's systems worked together most efficiently. Researchers monitor the performance of the 11,000-square-foot building, which boasts an energy cost savings of 63% for heating, cooling, and lighting. The basic plan of the building can be adapted to many needs, including retail and warehouse space. The Thermal Test Facility contains office and laboratory space; research focuses on the development of energy-efficiency and renewable energy technologies that are cost-effective and environmentally friendly

  11. Effects of Thermal Aging on Microstructure and Impact Properties of 316LN Stainless Steel Weld

    Directory of Open Access Journals (Sweden)

    LUO Qiang

    2017-12-01

    Full Text Available To study the thermal aging of nuclear primary pipe material 316LN stainless steel weld, accelerated thermal aging experiment was performed at 400℃ for 15000h. Microstructure evolution of weld after aging was investigated by TEM and HREM. Impact properties of weld thermally aged at different time was measured by Charpy impact test. Meanwhile, taking Charpy impact energy as the standard of thermal aging embrittlement, the thermal kinetics formula was obtained by the fitting method. Finally, the Charpy impact properties of the weld during 60 years of service at the actual operation temperature were estimated by the thermal kinetics formula. The results indicate that the spinodal decomposition occurs in the ferrite of the weld after thermal aging at 400℃ for 1000h, results in α (Fe-rich and α'(Cr-rich phases, and meanwhile, the G-phase is precipitated in the ferrite; the spinodal decomposition and the G-phase precipitation lead to the decrease in the impact energy of weld as time prolongs; the prediction results show that the Charpy impact energy of weld decreases quickly in the early 25 years, and then undergoes a slow decrease during the subsequent operation process.

  12. Structural and thermal properties of silk fibroin - Silver nanoparticles composite films

    Science.gov (United States)

    Shivananda, C. S.; Rao B, B. Lakshmeesha; Shetty, G. Rajesh; Sangappa, Y.

    2018-05-01

    In this work, silk fibroin-silver nanoparticles (SF-AgNPs) composite films have been prepared by simple solution casting method. The composite films were examined for structural and thermal properties using X-ray diffraction (XRD), thermogravimatric (TGA) and differential scanning calorimetry (DSC) analysis. The XRD results showed that with the introduction of AgNPs in the silk fibroin matrix the amorphous nature of the silk fibroin decreases with increasing nanoparticles concentration. The silk fibroin films possess good thermal stability with the presence of AgNPs.

  13. Managing the Mars Science Laboratory Thermal Vacuum Test for Safety and Success

    Science.gov (United States)

    Evans, Jordan P.

    2010-01-01

    The Mars Science Laboratory is a NASA/JPL mission to send the next generation of rover to Mars. Originally slated for launch in 2009, development problems led to a delay in the project until the next launch opportunity in 2011. Amidst the delay process, the Launch/Cruise Solar Thermal Vacuum Test was undertaken as risk reduction for the project. With varying maturity and capabilities of the flight and ground systems, undertaking the test in a safe manner presented many challenges. This paper describes the technical and management challenges and the actions undertaken that led to the ultimate safe and successful execution of the test.

  14. Thermal expansion properties of Bi-2212 in Ag or an Ag-alloy matrix

    International Nuclear Information System (INIS)

    Tenbrink, J.; Krauth, H.

    1994-01-01

    The thermal expansion properties of polycrystalline Bi 2 Sr 2 Ca 1 Cu 2 O 8+x melt-processed bulk specimens, and Bi 2 Sr 2 Ca 1 Cu 2 O 8+x monocore as well as multifilamentary round wires in Ag or Ag-alloy matrix have been investigated over the temperature range from -150 to 800 degrees C. Although the thermal expansion of Bi 2 Sr 2 Ca 1 Cu 2 O 8+x is distinctly lower compared with Ag, the thermal expansion properties of the Bi 2 Sr 2 Ca 1 Cu 2 O 8+x -Ag or AgNiMg-alloy composite conductors are essentially governed by the matrix material. The thermal expansion of the encountered oxide-dispersion-strengthened AgNiMg alloys is only slightly lower compared with that of pure Ag. Therefore the thermal expansion of all investigated Bi 2 Sr 2 Ca 1 Cu 2 O 8+x -Ag or Ag-alloy composite wires was found to be close to that of pure Ag. The reason for this striking behaviour is shown to be related to a surprisingly low elastic modulus of the polycrystalline Bi-2212 wire cores of the order of 10 to a maximum 40 GPa. (author)

  15. A study on the microstructural property and thermal property of Ti-alloys without Al as biomaterials

    International Nuclear Information System (INIS)

    Ban, Jae Sam; Lee, Kyung Won; Cho, Kyu Zong; Kim, Sun Jin

    2008-01-01

    Ti-10Ta-10Nb alloys were designed for surgical implants, dental and orthopedic materials without V and Al. Specimens of the Ti-10Ta-10Nb alloy were remelted three times through the consumable VAR process and were made into small rods. Homogenization heat treatment was carried out for 24 hours under a vacuum of 10 -3 torr and at constant temperature of 1050 .deg. C and then the specimens were cooled in water. After that, we observed the microstructure of the alloy by using an SEM. Rockwell (B) hardness, thermal expansion coefficient and specific heat of the Ti-10Ta-10Nb alloy were measured in order to examine the material properties. It was found that the mechanical property of the specimen was altered by the heat treatment, and thermal expansion coefficient and specific heat of the Ti-10Ta-10Nb alloy would be useful data for engineering processing design

  16. Local thermal property analysis by scanning thermal microscopy of an ultrafine-grained copper surface layer produced by surface mechanical attrition treatment

    Energy Technology Data Exchange (ETDEWEB)

    Guo, F.A. [Suzhou Institute for Nonferrous Metals Processing Technology, No. 200 Shenxu Road, Suzhou Industrial Park, Suzhou 215021 (China) and Unite de Thermique et d' Analyse Physique, Laboratoire d' Energetique et d' Optique, Universite de Reims, BP 1039, 51687 Reims Cedex 2 (France)]. E-mail: guofuan@yahoo.com; JI, Y.L. [Suzhou Institute for Nonferrous Metals Processing Technology, No. 200 Shenxu Road, Suzhou Industrial Park, Suzhou 215021 (China); Trannoy, N. [Unite de Thermique et d' Analyse Physique, Laboratoire d' Energetique et d' Optique, Universite de Reims, BP 1039, 51687 Reims Cedex 2 (France); Lu, J. [LASMIS, Universite de Technologie de Troyes, 12 Rue Marie Curie, Troyes 10010 (France)

    2006-06-15

    Scanning thermal microscopy (SThM) was used to map thermal conductivity images in an ultrafine-grained copper surface layer produced by surface mechanical attrition treatment (SMAT). It is found that the deformed surface layer shows different thermal conductivities that strongly depend on the grain size of the microstructure: the thermal conductivity of the nanostructured surface layer decreases obviously when compared with that of the coarse-grained matrix of the sample. The role of the grain boundaries in thermal conduction is analyzed in correlation with the heat conduction mechanism in pure metal. A theoretical approach, based on this investigation, was used to calculate the heat flow from the probe tip to the sample and then estimate the thermal conductivities at different scanning positions. Experimental results and theoretical calculation demonstrate that SThM can be used as a tool for the thermal property and microstructural analysis of ultrafine-grained microstructures.

  17. Prediction of thermal conductivity of rock through physico-mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Singh, T.N. [Department of Earth Sciences, Indian Institute of Technology, Bombay 400 076 (India); Sinha, S.; Singh, V.K. [Institute of Technology, Banaras Hindu University, Varanasi 221 005 (India)

    2007-01-15

    The transfer of energy between two adjacent parts of rock mainly depends on its thermal conductivity. Present study supports the use of artificial neural network (ANN) and adaptive neuro fuzzy inference system (ANFIS) in the study of thermal conductivity along with other intrinsic properties of rock due to its increasing importance in many areas of rock engineering, agronomy and geo environmental engineering field. In recent years, considerable effort has been made to develop techniques to determine these properties. Comparative analysis is made to analyze the capabilities among six different models of ANN and ANFIS. ANN models are based on feedforward backpropagation network with training functions resilient backpropagation (RP), one step secant (OSS) and Powell-Beale restarts (CGB) and radial basis with training functions generalized regression neural network (GRNN) and more efficient design radial basis network (NEWRB). A data set of 136 has been used for training different models and 15 were used for testing purposes. A statistical analysis is made to show the consistency among them. ANFIS is proved to be the best among all the networks tried in this case with average absolute percentage error of 0.03% and regression coefficient of 1, whereas best performance shown by the FFBP (RP) with average absolute error of 2.26%. Thermal conductivity is predicted using P-wave velocity, porosity, bulk density, uniaxial compressive strength of rock as input parameters. (author)

  18. Crystal structure and thermal property of polyethylene glycol octadecyl ether

    International Nuclear Information System (INIS)

    Meng, Jie-yun; Tang, Xiao-fen; Li, Wei; Shi, Hai-feng; Zhang, Xing-xiang

    2013-01-01

    Highlights: ► The crystal structure of C18En for n ≥ 20 is a monoclinic system. ► Polyethylene glycol octadecyl ether crystallizes perfectly. ► The number of repeat units has significant effect on the melting, crystallizing temperature and enthalpy. ► The thermal stable temperature increases rapidly with increasing the number of repeat unit. - Abstract: The crystal structure, phase change property and thermal stable temperature (T d ) of polyethylene glycol octadecyl ether [HO(CH 2 CH 2 O) n C 18 H 37 , C18En] with various numbers of repeat units (n = 2, 10, 20 and 100) as phase change materials (PCMs) were investigated using temperature variable Fourier transformed infrared spectroscopy (FTIR), wide-angle X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TG). C18En crystallizes perfectly at 0 °C; and the crystal structure for n ≥ 20 is a monoclinic system. The number of repeat units has great effect on the phase change properties of C18En. The thermal stable temperature increases rapidly with increasing the number of repeat units. They approach to that of PEG-2000 as the number of repeat units is more than 10. T d increases rapidly with increasing the number of repeat units. C18En are a series of promising polymeric PCMs

  19. Fabrication and laboratory-based performance testing of a building-integrated photovoltaic-thermal roofing panel

    International Nuclear Information System (INIS)

    Chen, Fangliang; Yin, Huiming

    2016-01-01

    Highlights: • A BIPVT solar panel is designed and fabricated for energy efficient buildings. • A high-speed manufacture method is developed to produce the functionally graded materials. • Laboratory tests demonstrate BIPVT’s energy efficiency improvement and innovations. • The PV efficiency is enhanced ∼24% through temperature control of the panel by water flow. • The combined electric and thermal efficiency reaches >75% of solar irradiation. - Abstract: A building integrated photovoltaic-thermal (BIPVT) multifunctional roofing panel has been developed in this study to harvest solar energy in the form of PV electricity as well as heat energy through the collection of warm water. As a key component of the multifunctional building envelope, an aluminum/high-density polyethylene (HDPE) functionally graded material (FGM) panel embedded with aluminum water tubes has been fabricated through the vibration-sedimentation approach. The FGM layer gradually transits material phases from well-conductive side (with aluminum dominated) to another highly insulated side (with HDPE). The heat in the PV cells can be easily transferred into the conductive side of the FGM and then collected by the water flow in the embedded tubes. Therefore, the operational temperature of the PV cells can be significantly lowered down, which recovers the PV efficiency in hot weather. In this way, the developed BIPVT panel is able to efficiently harvest solar energy in the form of both PV electricity and heat. The performance of a prototype BIPVT panel has been evaluated in terms of its thermal efficiency via warm water collection and PV efficiency via the output electricity. The laboratory test results demonstrate that significant energy conversion efficiency improvement can be achieved for both electricity generation and heat collection by the presented BIPVT roofing system. Overall, the performance indicates a very promising prospective of the new BIPVT multifunctional roofing panel.

  20. Measurement of unsaturated hydraulic properties and evaluation of property-transfer models for deep sedimentary interbeds, Idaho National Laboratory, Idaho

    Science.gov (United States)

    Perkins, Kimberlie; Johnson, Brittany D.; Mirus, Benjamin B.

    2014-01-01

    Operations at the Idaho National Laboratory (INL) have the potential to contaminate the underlying Eastern Snake River Plain (ESRP) aquifer. Methods to quantitatively characterize unsaturated flow and recharge to the ESRP aquifer are needed to inform water-resources management decisions at INL. In particular, hydraulic properties are needed to parameterize distributed hydrologic models of unsaturated flow and transport at INL, but these properties are often difficult and costly to obtain for large areas. The unsaturated zone overlying the ESRP aquifer consists of alternating sequences of thick fractured volcanic rocks that can rapidly transmit water flow and thinner sedimentary interbeds that transmit water much more slowly. Consequently, the sedimentary interbeds are of considerable interest because they primarily restrict the vertical movement of water through the unsaturated zone. Previous efforts by the U.S. Geological Survey (USGS) have included extensive laboratory characterization of the sedimentary interbeds and regression analyses to develop property-transfer models, which relate readily available physical properties of the sedimentary interbeds (bulk density, median particle diameter, and uniformity coefficient) to water retention and unsaturated hydraulic conductivity curves.

  1. Thermal properties of oil palm nano filler/kenaf reinforced epoxy hybrid nanocomposites

    Science.gov (United States)

    Saba, N.; Paridah, M. T.; Abdan, K.; Ibrahim, N. A.

    2016-11-01

    The aim of this research study was to fabricate nano oil palm empty fruit bunch (OPEFB)/kenaf/epoxy hybrid nanocomposites and to make comparative study on the thermal properties of nano OPEFB/kenaf/epoxy hybrid nanocomposites with the montmorillonite (MMT)/kenaf/epoxy hybrid nanocomposites and organically modified MMT (OMMT)/kenaf/epoxy hybrid nanocomposites. Epoxy based kenaf hybrid nanocomposites was prepared by dispersing the nano filler (nano OPEFB filler, MMT, OMMT) at 3% loading through high speed mechanical stirrer followed by hand lay-up technique. Thermal properties of hybrid nanocomposites were analyzed through thermogravimetry analyzer (TGA), and differential scanning calorimetry (DSC). Obtained results specified that addition of nano OPEFB filler improves the thermal stability and char yield of kenaf/epoxy composites. Furthermore, the increase in decomposition temperature by the nano OPEFB filler was quite comparable to the MMT/kenaf/epoxy but relatively less than OMMT/kenaf/epoxy hybrid nanocomposites. We concluded from overall consequences that the nano OPEFB filler can be used as the promising and innovative alternative of existing expensive nano filler, with relatively lesser impact on the environment having marked pronounced impact on the construction, automotive, aerospace, electronics and semiconducting sectors as future industries based on bio-wastes with satisfactory light weight and thermal stability on other side.

  2. Fabrication, thermal and electrical properties of polyphenylene sulphide/copper composites

    International Nuclear Information System (INIS)

    Goyal, R.K.; Kambale, K.R.; Nene, S.S.; Selukar, B.S.; Arbuj, S.; Mulik, U.P.

    2011-01-01

    Highlights: → Polyphenylene sulphide/copper composites show a low percolation threshold, i.e., about 6 vol% Cu. → Both pre- and post- glass transition coefficient of thermal expansion (CTE) of composites decreased significantly. → The microhardness was increased by more than 50% compared to pure PPS matrix. → The electrical conductivity was increased by about eight orders of magnitude for 18 vol% Cu composite. → Dielectric constant and dissipation factor of composites measured at MHz was increased to about 6-fold and 70-fold compared to PPS matrix. - Abstract: The thermal and electrical properties of high performance poly(phenylene sulphide) (PPS) composites reinforced up to 31 vol% Cu particles were investigated to be used as materials for electronic applications. The thermal stability and char yield of the composites increased significantly. Both pre- and post- glass transition coefficient of thermal expansion (CTE) of composites decreased significantly. The microhardness was increased by more than 50% compared to pure PPS matrix. Microhardness and CTE of composites correlated well with the rule of mixtures. A percolation threshold about 6 vol% Cu was obtained. The electrical conductivity was increased by about eight orders of magnitude for 18 vol% composite. Dielectric constant and dissipation factor of composites at 1 MHz was increased by about 6-fold and 70-fold compared to matrix, respectively. They decreased gradually with increasing frequency up to 1 MHz and thereafter, there was insignificant change. The scanning electron microscope showed almost uniform distribution of Cu particles in the matrix. Owing to better dimensional stability and good electrical properties, these composites are very promising for electronic applications.

  3. Thermal Site Descriptive Model. A strategy for the model development during site investigations. Version 1.0

    International Nuclear Information System (INIS)

    Sundberg, Jan

    2003-04-01

    Site investigations are in progress for the siting of a deep repository for spent nuclear fuel. As part of the planning work, strategies are developed for site descriptive modelling regarding different disciplines, amongst them the thermal conditions. The objective of the strategy for a thermal site descriptive model is to guide the practical implementation of evaluating site specific data during the site investigations. It is understood that further development may be needed. The model describes the thermal properties and other thermal parameters of intact rock, fractures and fracture zones, and of the rock mass. The methodology is based on estimation of thermal properties of intact rock and discontinuities, using both empirical and theoretical/numerical approaches, and estimation of thermal processes using mathematical modelling. The methodology will be used and evaluated for the thermal site descriptive modelling at the Aespoe Hard Rock Laboratory

  4. Thermal stability, swelling behavior and CO 2 absorption properties of Nanoscale Ionic Materials (NIMs)

    KAUST Repository

    Andrew Lin, Kun-Yi

    2014-11-11

    © The Royal Society of Chemistry 2015. Nanoscale Ionic Materials (NIMs) consist of a nanoscale core, a corona of charged brushes tethered on the surface of the core, and a canopy of the oppositely charged species linked to the corona. Unlike conventional polymeric nanocomposites, NIMs can display liquid-like behavior in the absence of solvents, have a negligible vapor pressure and exhibit unique solvation properties. These features enable NIMs to be a promising CO2 capture material. To optimize NIMs for CO2 capture, their structure-property relationships were examined by investigating the roles of the canopy and the core in their thermal stability, and thermally- and CO2-induced swelling behaviors. NIMs with different canopy sizes and core fractions were synthesized and their thermal stability as well as thermally- and CO2-induced swelling behaviors were determined using thermogravimetry, and ATR FT-IR and Raman spectroscopies. It was found that the ionic bonds between the canopy and the corona, as well as covalent bonds between the corona and the core significantly improved the thermal stability compared to pure polymer and polymer/nanofiller mixtures. A smaller canopy size and a larger core fraction led to a greater enhancement in thermal stability. This thermal stability enhancement was responsible for the long-term thermal stability of NIMs over 100 temperature swing cycles. Owing to their ordered structure, NIMs swelled less when heated or when they adsorbed CO2 compared to their corresponding polymers. This journal is

  5. Thermal stability, swelling behavior and CO 2 absorption properties of Nanoscale Ionic Materials (NIMs)

    KAUST Repository

    Andrew Lin, Kun-Yi; Park, Youngjune; Petit, Camille; Park, Ah-Hyung Alissa

    2014-01-01

    © The Royal Society of Chemistry 2015. Nanoscale Ionic Materials (NIMs) consist of a nanoscale core, a corona of charged brushes tethered on the surface of the core, and a canopy of the oppositely charged species linked to the corona. Unlike conventional polymeric nanocomposites, NIMs can display liquid-like behavior in the absence of solvents, have a negligible vapor pressure and exhibit unique solvation properties. These features enable NIMs to be a promising CO2 capture material. To optimize NIMs for CO2 capture, their structure-property relationships were examined by investigating the roles of the canopy and the core in their thermal stability, and thermally- and CO2-induced swelling behaviors. NIMs with different canopy sizes and core fractions were synthesized and their thermal stability as well as thermally- and CO2-induced swelling behaviors were determined using thermogravimetry, and ATR FT-IR and Raman spectroscopies. It was found that the ionic bonds between the canopy and the corona, as well as covalent bonds between the corona and the core significantly improved the thermal stability compared to pure polymer and polymer/nanofiller mixtures. A smaller canopy size and a larger core fraction led to a greater enhancement in thermal stability. This thermal stability enhancement was responsible for the long-term thermal stability of NIMs over 100 temperature swing cycles. Owing to their ordered structure, NIMs swelled less when heated or when they adsorbed CO2 compared to their corresponding polymers. This journal is

  6. Bio-composites based on polypropylene reinforced with Almond Shells particles: Mechanical and thermal properties

    International Nuclear Information System (INIS)

    Essabir, H.; Nekhlaoui, S.; Malha, M.; Bensalah, M.O.; Arrakhiz, F.Z.; Qaiss, A.; Bouhfid, R.

    2013-01-01

    Highlights: • Almond Shells (ASs) particles have been used as reinforcement in polypropylene matrix. • The SEBS-g-MA has been used to improve the adhesion between matrix and particles. • The mechanical and thermal properties of the composite have been improved by the AS. - Abstract: In this work, Almond Shells (ASs) particles are used as reinforcement in a thermoplastic matrix as polypropylene (PP). Composites containing Almond Shells (ASs) particles with and without compatibilizer (maleic anhydride grafted polypropylene; SEBS-g-MA) for various particle content (5, 10, 15, 20, 25, 30 wt.%) was investigated by means of studying their mechanical, thermal and rheological properties. The composites were prepared in a twin-screw extruder and assessed by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), tensile testing and Dynamic Mechanical Analysis (DMA). Results show a clear improvement in mechanical and rheological properties from the use of Almond Shells particles in the matrix without and with maleic anhydride compatibilizer, corresponding to a gain in Young’s modulus of 56.2% and 35% respectively, at 30 wt.% particle loading. Thermal analysis revealed that incorporation of particle in the composites resulted in increase in the initial thermal decomposition temperatures

  7. Evaluation of mechanical and thermal properties of insulation materials for HTS power devices at liquid nitrogen temperature

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Hyung Seop; Diaz, Mark Angelo [Dept. of Mechanical Design Engineering, Andong National University, Andong (Korea, Republic of)

    2017-06-15

    In superconducting power devices including power cables in which high temperature superconducting (HTS) tapes are utilized, a reliable electrical insulation should be achieved for its maximum performance. For an efficient design of HTS superconducting devices, a comparative evaluation of the mechanical and thermal propperties for various insulation materials at cryogenic temperatures is required. Especially, in the process of the property evaluation of the sheet-shaped insulation materials, anisotropy according to the machining direction should be considered because the mechanical and thermal properties are significantly influenced by the sample orientation. In this study, the cryogenic thermal and mechanical properties of various insulation material sheets such as PPLP, Cryoflex, Teflon, and Kapton were determined considering sample orientation. All samples tested at cryogenic temperature showed significantly higher tensile strength as compared with that of room temperature. The ultimate tensile strength at both temperature conditions significantly depended upon the sample orientation. The thermal properties of the insulation materials exhibited a slight difference among samples depending on the orientation: for the PPLP and Cryoflex, the CD orientation showed larger thermal contraction up to 77 K as compared to the MD one. MD samples in PPLP and Cryoflex showed a lower CTE and thermal contraction which made it more promising as an insulation material due to its comparable CTE with HTS CC tapes.

  8. Preparation and thermal properties characterization of carbonate salt/carbon nanomaterial composite phase change material

    International Nuclear Information System (INIS)

    Tao, Y.B.; Lin, C.H.; He, Y.L.

    2015-01-01

    Highlights: • Nanocomposite phase change materials were prepared and characterized. • Larger specific surface area is more efficient to enhance specific heat. • Columnar structure is more efficient to enhance thermal conductivity. • Thermal conductivity enhancement is the key. • Single walled carbon nanotube is the optimal nanomaterial additive. - Abstract: To enhance the performance of high temperature salt phase change material, four kinds of carbon nanomaterials with different microstructures were mixed into binary carbonate eutectic salts to prepare carbonate salt/nanomaterial composite phase change material. The microstructures of the nanomaterial and composite phase change material were characterized by scanning electron microscope. The thermal properties such as melting point, melting enthalpy, specific heat, thermal conductivity and total thermal energy storage capacity were characterized. The results show that the nanomaterial microstructure has great effects on composite phase change material thermal properties. The sheet structure Graphene is the best additive to enhance specific heat, which could be enhanced up to 18.57%. The single walled carbon nanotube with columnar structure is the best additive to enhance thermal conductivity, which could be enhanced up to 56.98%. Melting point increases but melting enthalpy decreases with nanomaterial specific surface area increase. Although the additives decrease the melting enthalpy of composite phase change material, they also enhance the specific heat. As a combined result, the additives have little effects on thermal energy storage capacity. So, for phase change material performance enhancement, more emphasis should be placed on thermal conductivity enhancement and single walled carbon nanotube is the optimal nanomaterial additive

  9. A review of recent measurements of optical and thermal properties of α-mercuric iodide

    International Nuclear Information System (INIS)

    Burger, A.; Morgan, S.H.; Silberman, E.; Nason, D.; Cheng, A.Y.

    1991-01-01

    The knowledge of the physical properties of a crystal and their relation to the nature and content of defects are essential for both applications and fundamental reasons. Alpha-mercuric iodide (α-HgI 2 ) is a material which was found important applications as room temperature X-ray and gamma ray detectors. Some recent thermal and optical measurements of this material, using the samples of improved crystallinity which are now available, are reviewed below. Heretofore, these properties have received less attention than the mechanical and electrical properties, particularly at elevated temperatures. In the technology of α-HgI 2 where there is a continuing motivation to obtain larger single crystals without compromising the material quality, a better knowledge of the thermal and optical properties may lead to improvements in the processes of material purification, crystal growth and device fabrication

  10. Effects of Inorganic Fillers on the Thermal and Mechanical Properties of Poly(lactic acid).

    Science.gov (United States)

    Liu, Xingxun; Wang, Tongxin; Chow, Laurence C; Yang, Mingshu; Mitchell, James W

    Addition of filler to polylactic acid (PLA) may affect its crystallization behavior and mechanical properties. The effects of talc and hydroxyapatite (HA) on the thermal and mechanical properties of two types of PLA (one amorphous and one semicrystalline) have been investigated. The composites were prepared by melt blending followed by injection molding. The molecular weight, morphology, mechanical properties, and thermal properties have been characterized by gel permeation chromatography (GPC), scanning electron microscope (SEM), instron tensile tester, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). It was found that the melting blending led to homogeneous distribution of the inorganic filler within the PLA matrix but decreased the molecular weight of PLA. Regarding the filler, addition of talc increased the crystallinity of PLA, but HA decreased the crystallinity of PLA. The tensile strength of the composites depended on the crystallinity of PLA and the interfacial properties between PLA and the filler, but both talc and HA filler increased the toughness of PLA.

  11. Effects of Inorganic Fillers on the Thermal and Mechanical Properties of Poly(lactic acid

    Directory of Open Access Journals (Sweden)

    Xingxun Liu

    2014-01-01

    Full Text Available Addition of filler to polylactic acid (PLA may affect its crystallization behavior and mechanical properties. The effects of talc and hydroxyapatite (HA on the thermal and mechanical properties of two types of PLA (one amorphous and one semicrystalline have been investigated. The composites were prepared by melt blending followed by injection molding. The molecular weight, morphology, mechanical properties, and thermal properties have been characterized by gel permeation chromatography (GPC, scanning electron microscope (SEM, instron tensile tester, thermogravimetric analysis (TGA, differential scanning calorimetry (DSC, and dynamic mechanical analysis (DMA. It was found that the melting blending led to homogeneous distribution of the inorganic filler within the PLA matrix but decreased the molecular weight of PLA. Regarding the filler, addition of talc increased the crystallinity of PLA, but HA decreased the crystallinity of PLA. The tensile strength of the composites depended on the crystallinity of PLA and the interfacial properties between PLA and the filler, but both talc and HA filler increased the toughness of PLA.

  12. A new method for measuring the thermal regulatory properties of phase change material (PCM) fabrics

    International Nuclear Information System (INIS)

    Wan, X; Fan, J

    2009-01-01

    Several methods already exist for the measurement of the thermal regulatory properties of fabrics containing phase change materials (PCMs). However, they do not adequately simulate the actual use condition; consequently the measurements may not have relevance to the performance of PCM fabrics in actual use. Here we report on the development of a new method, which better simulates the real use situation. In this method, a hot plate, simulating the human body, generates a constant amount of heat depending on the type of human activity to be simulated. The hot plate covered by the PCM fabric is then exposed to a thermal transient simulating a wearer moving from one thermal environment to another; the changes of surface temperature and heat loss of the hot plate are then recorded and used to characterize the thermal regulatory properties of the PCM fabrics

  13. Thermal and microstructural properties of fine-grained material at the Viking Lander 1 site

    Science.gov (United States)

    Paton, M. D.; Harri, A.-M.; Savijärvi, H.; Mäkinen, T.; Hagermann, A.; Kemppinen, O.; Johnston, A.

    2016-06-01

    As Viking Lander 1 touched down on Mars one of its footpads fully penetrated a patch of loose fine-grained drift material. The surrounding landing site, as observed by VL-1, was found to exhibit a complex terrain consisting of a crusted surface with an assortment of rocks, large dune-like drifts and smaller patches of drift material. We use a temperature sensor attached to the buried footpad and covered in fine-grained material to determine the thermal properties of drift material at the VL-1 site. The thermal properties are used to investigate the microstructure of the drift material and understand its relevance to surface-atmosphere interactions. We obtained a thermal inertia value of 103 ± 22 tiu. This value is in the upper range of previous thermal inertia estimates of martian dust as measured from orbit and is significantly lower than the regional thermal inertia of the VL-1 site, of around 283 tiu, obtained from orbit. We estimate a thermal inertia of around 263 ± 29 tiu for the duricrust at the VL-1 site. It was noted the patch of fine-grained regolith around the footpad was about 20-30 K warmer compared to similar material beyond the thermal influence of the lander. An effective diameter of 8 ± 5 μm was calculated for the particles in the drift material. This is larger than atmospheric dust and large compared to previous estimates of the drift material particle diameter. We interpret our results as the presence of a range of particle sizes, <8 μm, in the drift material with the thermal properties being controlled by a small amount of large particles (∼8 μm) and its cohesion being controlled by a large amount of smaller particles. The bulk of the particles in the drift material are therefore likely comparable in size to that of atmospheric dust. The possibility of larger particles being locked into a fine-grained material has implications for understanding the mobilisation of wind blown materials on Mars.

  14. Mechanical and Thermal Properties of Styrene Butadiene Rubber - Functionalized Carbon Nanotubes Nanocomposites

    KAUST Repository

    Laoui, Tahar

    2013-01-01

    The effect of reinforcing styrene butadiene rubber (SBR) with functionalized carbon nanotubes on the mechanical and thermal properties of the nanocomposite was investigated. Multi-walled carbon nanotubes (CNTs) were functionalized with phenol

  15. A first principles study of the electronic structure, elastic and thermal properties of UB{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Jossou, Ericmoore, E-mail: ericmoore.jossou@usask.ca [Department of Mechanical Engineering, College of Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, S7N 5A9, Saskatchewan (Canada); Malakkal, Linu [Department of Mechanical Engineering, College of Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, S7N 5A9, Saskatchewan (Canada); Szpunar, Barbara; Oladimeji, Dotun [Department of Physics and Engineering Physics, College of Art and Science, University of Saskatchewan, 116 Science Place, Saskatoon, S7N 5E2, Saskatchewan (Canada); Szpunar, Jerzy A. [Department of Mechanical Engineering, College of Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, S7N 5A9, Saskatchewan (Canada)

    2017-07-15

    Uranium diboride (UB{sub 2}) has been widely deployed for refractory use and is a proposed material for Accident Tolerant Fuel (ATF) due to its high thermal conductivity. However, the applicability of UB{sub 2} towards high temperature usage in a nuclear reactor requires the need to investigate the thermomechanical properties, and recent studies have failed in highlighting applicable properties. In this work, we present an in-depth theoretical outlook of the structural and thermophysical properties of UB{sub 2}, including but not limited to elastic, electronic and thermal transport properties. These calculations were performed within the framework of Density Functional Theory (DFT) + U approach, using Quantum ESPRESSO (QE) code considering the addition of Coulomb correlations on the uranium atom. The phonon spectra and elastic constant analysis show the dynamic and mechanical stability of UB{sub 2} structure respectively. The electronic structure of UB{sub 2} was investigated using full potential linear augmented plane waves plus local orbitals method (FP-LAPW+lo) as implemented in WIEN2k code. The absence of a band gap in the total and partial density of states confirms the metallic nature while the valence electron density plot reveals the presence of covalent bond between adjacent B-B atoms. We predicted the lattice thermal conductivity (k{sub L}) by solving Boltzmann Transport Equation (BTE) using ShengBTE. The second order harmonic and third-order anharmonic interatomic force constants required as input to ShengBTE was calculated using the Density-functional perturbation theory (DFPT). However, we predicted the electronic thermal conductivity (k{sub el}) using Wiedemann-Franz law as implemented in Boltztrap code. We also show that the sound velocity along ‘a’ and ‘c’ axes exhibit high anisotropy, which accounts for the anisotropic thermal conductivity of UB{sub 2}. - Highlights: •Prediction of electronic structure and thermophysical properties of UB

  16. Effect of chemical treatment on thermal properties of fibers from pineapple

    International Nuclear Information System (INIS)

    Fernandes, Rafael I.M.; Mulinari, Daniella R.; Carvalho, Kelly C.C.; Conejo, Luiza dos Santos; Voorwald, Herman J.C.; Cioffi, Maria Odila H.

    2009-01-01

    In this work the effect of the chemical modification of natural fibres from of pineapple fibres with alkaline solution was studied. After modification the in nature and modified fibres were analyzed by XRD diffractometry and thermogravimetry with objective to evaluate influence chemical treatment in surface and in the thermal properties fibres. With the obtained results it was possible to verify an increase of 10.4 % in the crystallinity index of fibres beyond the increase around 4.5% in the degradation temperature, what it indicates an increase in the stability thermal of the fibres. (author)

  17. Vulcanization Kinetics and Mechanical Properties of Ethylene Propylene Diene Monomer Thermal Insulation

    Directory of Open Access Journals (Sweden)

    Mohamad Irfan Fathurrohman

    2015-07-01

    Full Text Available The vulcanization kinetics of Ethylene-propylene diene monomer (EPDM rubber thermal insulation was studied by using rheometer under isothermal condition at different temperatures. The rheometry analysis was used to determining the cure kinetic parameters and predicting the cure time of EPDM thermal insulation. The experimental results revealed that the curing curves of EPDM thermal insulation were marching and the optimum curing time decreased with increasing the temperature. The kinetic parameters were determined from the autocatalytic model showed close fitting with the experimental results, indicating suitability of autocatalytic model in characterizing the cure kinetics. The activation energy was determined from the autocatalytic model is 46.3661 kJ mol-1. The cure time were predicted from autocatalytic model and the obtained kinetic parameter by using the relationship among degree of conversion, cure temperature, and cure time. The predictions of cure time provide information for the actual curing characteristic of EPDM thermal insulation. The mechanical properties of EPDM thermal insulation with different vulcanization temperatures showed the same hardness, tensile strength and modulus at 300%, except at temperature 70 °C, while the elongation at breaking point decreased with increasing temperature of vulcanization. © 2015 BCREC UNDIP. All rights reservedReceived: 8th April 2014; Revised: 7th January 2015; Accepted: 16th January 2015How to Cite: Fathurrohman, M.I., Maspanger, D.R., Sutrisno, S. (2015. Vulcanization Kinetics and Mechanical Properties of Ethylene Propylene Diene Monomer Thermal Insulation. Bulletin of Chemi-cal Reaction Engineering & Catalysis, 10 (2, 104-110. (doi:10.9767/bcrec.10.2.6682.104-110Permalink/DOI: http://dx.doi.org/10.9767/bcrec.10.2.6682.104-110 

  18. High-field thermal transports properties of REBCO coated conductors

    CERN Document Server

    Bonura, M

    2015-01-01

    The use of REBCO coated conductors is envisaged for many applications, extending from power cables to high-field magnets. Whatever the case, thermal properties of REBCO tapes play a key role for the stability of superconducting devices. In this work, we present the first study on the longitudinal thermal conductivity (k) of REBCO coated conductors in magnetic fields up to 19 T applied both parallelly and perpendicularly to the thermal-current direction. Copper-stabilized tapes from six industrial manufacturers have been investigated. We show that zero-field k of coated conductors can be calculated with an accuracy of ‡ 15% from the residual resistivity ratio of the stabilizer and the Cu/non-Cu ratio. Measurements performed at high fields have allowed us to evaluate the consistency of the procedures generally used for estimating in-field k in the framework of the Wiedemann-Franz law from an electrical characterization of the materials. In-field data are intended to provide primary ingredients for the ...

  19. Computational micromagnetics: prediction of time dependent and thermal properties

    International Nuclear Information System (INIS)

    Schrefl, T.; Scholz, W.; Suess, Dieter; Fidler, J.

    2001-01-01

    Finite element modeling treats magnetization processes on a length scale of several nanometers and thus gives a quantitative correlation between the microstructure and the magnetic properties of ferromagnetic materials. This work presents a novel finite element/boundary element micro-magnetics solver that combines a wavelet-based matrix compression technique for magnetostatic field calculations with a BDF/GMRES method for the time integration of the Gilbert equation of motion. The simulations show that metastable energy minima and nonuniform magnetic states within the grains are important factors in the reversal dynamics at finite temperature. The numerical solution of the Gilbert equation shows how reversed domains nucleate and expand. The switching time of submicron magnetic elements depends on the shape of the elements. Elements with slanted ends decrease the overall reversal time, as a transverse demagnetizing field suppresses oscillations of the magnetization. Thermal activated processes can be included adding a random thermal field to the effective magnetic field. Thermally assisted reversal was studied for CoCrPtTa thin-film media

  20. Spectroscopic and thermal properties of uranium relevant to atomic schemes for laser isotope separation

    International Nuclear Information System (INIS)

    Ahmad, S.A.; Pandey, P.L.

    1980-01-01

    Spectroscopic data on uranium atom and thermal properties of uranium relevant to atomic schemes for laser isotope separation have been presented in this report. All the relevant spectroscopic data reported in literature so far, as well as some other parameters like photo-absorption cross sections, branching ratios, effects of magnetic and electric fields, evaluated using the existing data, have been presented here. Among the thermal properties, parameters like vapour pressure and number densities for U/Liquid U, U/URe 2 and U/UP systems, partition function, percentage population distribution in energy levels, thermal ionisation and velocities of uranium atom have been presented at different temperatures. Different possible collision processes are mentioned and cross-sections of U-U + charge-exchange and U + + e radiative recombination processes have been also evaluated. (author)

  1. Thermal Properties of Starch From New Corn Lines as Impacted by Environment and During Line Development

    Energy Technology Data Exchange (ETDEWEB)

    Lenihan, Elizabeth M [Iowa State Univ., Ames, IA (United States)

    2003-01-01

    The objectives of this research were to further characterize exotic by adapted corn inbreds by studying the impact of environment on their starch thermal properties, and investigating the development of starch thermal properties during kernel maturation by using differential scanning calorimetry (DSC). A method to expedite identification of unusual starch thermal traits was investigated by examining five corn kernels at a time, instead of one kernel, which the previous screening methods used. Corn lines with known thermal functions were blended with background starch (control) in ratios of unique starch to control starch, and analyzed by using DSC. Control starch was representative of typical corn starch. The values for each ratio within a mutant type were unique (α < 0.01) for most DSC measurements. These results supported the five-kernel method for rapidly screening large amounts of corn germplasm to identify unusual starch traits. The effects of 5 growing locations on starch thermal properties from exotic by adapted corn and Corn Belt lines were studied using DSC. The warmest location, Missouri, generally produced starch with greater gelatinization onset temperature (ToG), narrower range of gelatinization (RG), and greater enthalpy of gelatinization (ΔHG). The coolest location, Illinois, generally resulted in starch with lower ToG, wider RG, and lower ΔHG. Starch from the Ames 1 farm had thermal properties similar to those of Illinois, whereas starch from the Ames 2 farm had thermal properties similar to those of Missouri. The temperature at Ames 2 may have been warmer since it was located near a river; however, soil type and quality also were different. Final corn starch structure and function change during development and maturity. Thus, the changes in starch thermal properties during 5 stages of endosperm development from exotic by adapted corn and Corn Belt lines at two locations were

  2. Response of neutron-irradiated RPV steels to thermal annealing

    International Nuclear Information System (INIS)

    Iskander, S.K.; Sokolov, M.A.; Nanstad, R.K.

    1997-01-01

    One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPVs) is to thermally anneal them to restore the fracture toughness properties that have been degraded by neutron irradiation. This paper summarizes experimental results of work performed at the Oak Ridge National Laboratory (ORNL) to study the annealing response of several irradiated RPV steels

  3. Thermal properties of typical chernozems in Kursk Oblast

    Science.gov (United States)

    Arkhangel'skaya, T. A.; Velichenko, M. V.; Tikhonravova, P. I.

    2016-10-01

    Thermal diffusivity and heat capacity of virgin and plowed heavy loamy typical chernozems of Kursk oblast were studied. Thermal diffusivity was determined in the course of step-by-step drying of the initially capillary-saturated samples to the air-dry state. Specific heat capacity was determined for absolutely dry samples. Volumetric heat capacity was calculated according to the de Vries equation. Thermal diffusivity varied within the ranges of (1.15-3.46) × 10-7 m2/s in the Ap horizon, (1.14-3.35) × 10-7 m2/s in the A1 horizon, (1.49-3.70) × 10-7 m2/s in the AB horizon, (1.49-3.91) × 10-7 m2/s in the B1 horizon, and (1.60-3.80) × 10-7 m2/s in the Bca horizon. The thermal diffusivity vs. water content dependencies had distinct maximums and were flattened in the range of low water contents. The maximums were most pronounced for the mineral B1 and Bca horizons; for the A1 and Ap horizons, the curves were rather S-shaped. Volumetric heat capacity of the air-dry soils varied from 0.96 J/(cm3 K) in the A1 horizon to 1.31 J/(cm3 K) in the Bca horizon; in the state of capillary saturation, it varied from 2.79 J/(cm3 K) in the A1 horizon to 3.28 J/(cm3 K) in the Bca horizon. Thermal properties of topsoil horizons were higher in the plowed chernozem compared with the virgin chernozem, which is explained by an increase in the bulk density and a decrease in the organic matter content in the plowed soil.

  4. Influence of dioctyl phthalate (DOP) on the mechanical, optical and thermal properties of formulations for the industrial manufacture of radiation sterilizable medical disposables

    Science.gov (United States)

    Ahmed, Shamshad; Mehmood, Mazhar; Iqbal, Rashid

    2010-03-01

    Shelf life of the formulations designed for the industrial manufacture of radiation sterilizable syringes and other medical disposables is a very important issue world over. Radiation compatible formulations were developed earlier in the laboratory by the incorporation of primary and secondary antioxidants along with processing stabilizers in a random polypropylene copolymer. It has been reported in literature that the mobilizing agents namely hydrocarbons, greases, wax and the plasticizer, dioctyl phthalate (DOP) impart radiation resistance to the polypropylene by providing free volume. It was envisaged that the addition of DOP to the afore-mentioned formulation might favorably influence the mechanical, optical and thermal properties of our formulation. To study the influence of addition of DOP on the afore-mentioned properties, the addition of 1%, 2% and 3% of the mobilizer was made, followed by the irradiation of resulting heat pressed sheets to the industrial standard dose of 25 kGy. Two important characteristic mechanical properties to determine the suitability of the radiation sterilized materials comprise angle of breakage and the haze percent. After irradiation and even on accelerated ageing of the irradiated material, the angle of breakage of heat press sheets of formulations containing 1%, 2% and 3% of DOP was found to be 180°, demonstrating the role of DOP, in imparting additional radiation stability. In case of the irradiated control sample, the angle of breakage was much lower. In the heat pressed sheets containing the DOP, a remarkable retention in the tensile strength, percentage elongation at break, along with improved thermal stability was observed. The formulation devoid of DOP demonstrated poor retention of the afore-mentioned characteristic properties .The observed improvement in thermal stability of the formulations containing DOP hints at the likely possibility of reuse of these materials by autoclaving which is considered an additional

  5. Influence of dioctyl phthalate (DOP) on the mechanical, optical and thermal properties of formulations for the industrial manufacture of radiation sterilizable medical disposables

    International Nuclear Information System (INIS)

    Ahmed, Shamshad; Mehmood, Mazhar; Iqbal, Rashid

    2010-01-01

    Shelf life of the formulations designed for the industrial manufacture of radiation sterilizable syringes and other medical disposables is a very important issue world over. Radiation compatible formulations were developed earlier in the laboratory by the incorporation of primary and secondary antioxidants along with processing stabilizers in a random polypropylene copolymer. It has been reported in literature that the mobilizing agents namely hydrocarbons, greases, wax and the plasticizer, dioctyl phthalate (DOP) impart radiation resistance to the polypropylene by providing free volume. It was envisaged that the addition of DOP to the afore-mentioned formulation might favorably influence the mechanical, optical and thermal properties of our formulation. To study the influence of addition of DOP on the afore-mentioned properties, the addition of 1%, 2% and 3% of the mobilizer was made, followed by the irradiation of resulting heat pressed sheets to the industrial standard dose of 25 kGy. Two important characteristic mechanical properties to determine the suitability of the radiation sterilized materials comprise angle of breakage and the haze percent. After irradiation and even on accelerated ageing of the irradiated material, the angle of breakage of heat press sheets of formulations containing 1%, 2% and 3% of DOP was found to be 180 deg, demonstrating the role of DOP, in imparting additional radiation stability. In case of the irradiated control sample, the angle of breakage was much lower. In the heat pressed sheets containing the DOP, a remarkable retention in the tensile strength, percentage elongation at break, along with improved thermal stability was observed. The formulation devoid of DOP demonstrated poor retention of the afore-mentioned characteristic properties .The observed improvement in thermal stability of the formulations containing DOP hints at the likely possibility of reuse of these materials by autoclaving which is considered an additional

  6. Preparation and properties of highly conductive palmitic acid/graphene oxide composites as thermal energy storage materials

    International Nuclear Information System (INIS)

    Mehrali, Mohammad; Latibari, Sara Tahan; Mehrali, Mehdi; Indra Mahlia, Teuku Meurah; Cornelis Metselaar, Hendrik Simon

    2013-01-01

    PA/GO (palmitic acid/graphene oxide) as PCMs (phase change materials) prepared by vacuum impregnation method, have high thermal conductivity. The GO (graphene oxide) composite was used as supporting material to improve thermal conductivity and shape stabilization of composite PCM (phase change material). SEM (Scanning electronic microscope), FT-IR (Fourier transformation infrared spectroscope) and XRD (X-ray diffractometer) were applied to determine microstructure, chemical structure and crystalloid phase of palmitic acid/GO composites, respectively. DSC (Differential scanning calorimeter) test was done to investigate thermal properties which include melting and solidifying temperatures and latent heat. FT-IR analysis represented that the composite instruction of porous palmitic acid and GO were physical. The temperatures of melting, freezing and latent heats of the composite measured through DSC analysis were 60.45, 60.05 °C, 101.23 and 101.49 kJ/kg, respectively. Thermal cycling test showed that the form-stable composite PCM has good thermal reliability and chemical stability. Thermal conductivity of the composite PCM was improved by more than three times from 0.21 to 1.02. As a result, due to their acceptable thermal properties, good thermal reliability, chemical stability and great thermal conductivities, we can consider the prepared form-stable composites as highly conductive PCMs for thermal energy storage applications. - Highlights: • Novel composite PCM with high thermal conductivity and latent heat storage. • New thermal cycling test for thermal reliability of composite PCMs. • Increasing thermal conductivity of composite PCM with graphene oxide. • Increasing thermal stability of phase change material by adding graphene oxide

  7. Structure and thermal properties of as-fabricated U-7Mo/Mg and U-10Mo/Mg low-enriched uranium research reactor fuels

    Energy Technology Data Exchange (ETDEWEB)

    Kulakov, Mykola, E-mail: mykola.kulakov@cnl.ca [Fuel Development Branch, Canadian Nuclear Laboratories, Chalk River, ON K0J 1J0 Canada (Canada); Saoudi, Mouna [Fuel Development Branch, Canadian Nuclear Laboratories, Chalk River, ON K0J 1J0 Canada (Canada); Piro, Markus H.A. [Fuel and Fuel Channel Safety Branch, Canadian Nuclear Laboratories, Chalk River, ON K0J 1J0 Canada (Canada); Donaberger, Ronald L. [Canadian Neutron Beam Centre, Chalk River, ON K0J 1J0 Canada (Canada)

    2017-02-15

    Aluminum-clad U-7Mo/Mg and U-10Mo/Mg pin-type mini-elements (with a core uranium loading of 4.5 gU/cm{sup 3}) have been fabricated at the Canadian Nuclear Laboratories for experimental tests and ultimately for use in research and test reactors. In this study, the microstructure and phase composition of unirradiated U-7Mo/Mg and U-10Mo/Mg fuel cores were analyzed using optical and scanning electron microscopy, and neutron powder diffraction. Thermal properties were characterized using a combination of experimental measurements and thermodynamic calculations. The thermal diffusivity was measured using the laser flash method. The temperature-dependent specific heat capacities were calculated based on the linear rule of mixture using the weight fraction of different crystalline phases and their specific heat capacity values taken from the literature. The thermal conductivity was then calculated using the measured thermal diffusivity, the measured density and the calculated specific heat capacity. The resulting thermal conductivity is practically identical for both types of fuel. The in-reactor temperatures were predicted using conjugate heat transfer simulations. - Highlights: • Neutron diffraction analysis shows that most of the γ-U(Mo) phase was retained in as-fabricated U-7Mo/Mg and U-10Mo/Mg fuel cores. • The experimental thermal conductivity of both types of fuel is practically identical. • Based on conjugate heat transfer simulations, under normal operating conditions, the in-reactor fuel centreline temperature is about 510 K.

  8. Thermal property prediction and measurement of organic phase change materials in the liquid phase near the melting point

    International Nuclear Information System (INIS)

    O’Connor, William E.; Warzoha, Ronald; Weigand, Rebecca; Fleischer, Amy S.; Wemhoff, Aaron P.

    2014-01-01

    Highlights: • Liquid-phase thermal properties for five phase change materials were estimated. • Various liquid phase and phase transition thermal properties were measured. • The thermal diffusivity was found using a best path to prediction approach. • The thermal diffusivity predictive method shows 15% agreement for organic PCMs. - Abstract: Organic phase change materials (PCMs) are a popular choice for many thermal energy storage applications including solar energy, building envelope thermal barriers, and passive cooling of portable electronics. Since the extent of phase change during a heating or cooling process is dependent upon rapid thermal penetration into the PCM, accurate knowledge of the thermal diffusivity of the PCM in both solid and liquid phases is crucial. This study addresses the existing gaps in information for liquid-phase PCM properties by examining an approach that determines the best path to prediction (BPP) for the thermal diffusivity of both alkanes and unsaturated acids. Knowledge of the BPP will enable researchers to explore the influence of PCM molecular structure on bulk thermophysical properties, thereby allowing the fabrication of optimized PCMs. The BPP method determines which of the tens of thousands of combinations of 22 different available theoretical techniques provides best agreement with thermal diffusivity values based on reported or measured density, heat capacity, and thermal conductivity for each of five PCMs (heneicosane, tricosane, tetracosane, oleic acid, and linoleic acid) in the liquid phase near the melting point. Separate BPPs were calibrated for alkanes based on heneicosane and tetracosane, and for the unsaturated acids. The alkane and unsaturated acid BPPs were then tested on a variety of similar materials, showing agreement with reported/measured thermal diffusivity within ∼15% for all materials. The alkane BPP was then applied to find that increasing the length of alkane chains decreases the PCM thermal

  9. An experimental study on thermal properties of composite insulation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Gyoung-Seok [Building and Urban Research Department, Korea Institute of Construction Technology, 2311 Daehwa-Dong, Ilsanseo-Gu, Goyang-Si, Gyeonggi-Do 411-712 (Korea); College of Architecture, Hanyang University, 17, Hangdang-Dong, Sungdong-Gu, Seoul 133-791 (Korea); Kang, Jae-Sik; Jeong, Young-Sun; Lee, Seung-Eon [Building and Urban Research Department, Korea Institute of Construction Technology, 2311 Daehwa-Dong, Ilsanseo-Gu, Goyang-Si, Gyeonggi-Do 411-712 (Korea); Sohn, Jang-Yeul [College of Architecture, Hanyang University, 17, Hangdang-Dong, Sungdong-Gu, Seoul 133-791 (Korea)

    2007-04-01

    In accordance with the insulation standards reinforced since 2001 and the compulsory standards on floor impact sound insulation that have been enforced since 2004, insulation materials for actual buildings have been converted to composite materials and new insulation materials have been released in the market. However, Korea is lagging behind the world in fundamental experimental studies and resources. In case of some composite insulation materials, there also have been problems of distorted performance occurring as a result of tests being conducted without having verification and evaluation on the accuracy and inaccuracy of such tests. Therefore, this study grasped the thermal properties of composite insulation materials using thermal conductivity test equipment by heat flux method, and performed quantitative evaluation on the measurement precision and uncertainty of composite materials. (author)

  10. Study on thermal and mechanical properties of U-tube materials for steam generator

    International Nuclear Information System (INIS)

    Rheu, Woo Suk; Kang, Young Hwan; Park, Jong Man; Joo, Ki Nam; Kim, Sung Soo; Maeng, Wan Young; Park, Se Jin

    1993-01-01

    Most of domestic nuclear plants have used I600 TT material for steam generator U-tube, and piled up the field experience. I600 HTMA and I690 TT, however, are recommended for an alternative of U-tube by ABB-CE since YK-3 and 4. Field experience of I600 HTMA and I690 TT have not compiled in the country, so it is concerned to select the future materials for U-tube. Thus, database on the thermal and mechanical properties of U-tube materials is very necessary for design documentations. In this study, the thermal, mechanical and metallugical properties were tested and evaluated to establish the database for steam generator U-tube. In addition, thermal conductivity of I600 and I690 was measured and compared statistically, providing a basic document for applying I690 to U-tube. The results will be used to improve the manufacturing process in order to increase the integrity of U-tube. (Author)

  11. Thermal Properties of Beryllium Metal

    International Nuclear Information System (INIS)

    Cho, Tae Won; Baek, Je Kyun; Jeong, Gwan Yoon; Kim, Ji Hyeon; Sohn, Dong Seong

    2013-01-01

    It is known that the presence of as-fabricated porosity largely affect thermal conductivity of beryllium. Therefore, in this paper we will suggest a new thermal conductivity equation which consider volume fraction and discuss how this can be applied to irradiation induced degradation of thermal conductivity later. This study was performed to develop a new correlation of thermal conductivity of Beryllium. Although there are many factors like BeO contents, impurity level, grain size, and porosity, we assumed porosity will be the dominant factor for thermal conductivity. Therefore, a new correlation which consider volume fraction by applying Maxwell-Eucken equation is developed and this is consistent to some degrees. However, increasing impurity level and decreasing grain size will decrease thermal conductivity. Therefore, we need to consider their effects although we assume BeO contents, impurity, and grain size do not make noticeable effects in the future. Furthermore, thermal conductivity degradation by neutron irradiation should be considered afterward. There are two main factors for the thermal conductivity degradation: the one is defects formed by neutron collisions and the other is helium generated by transmutation of Be. It is known that they make a considerable degradation of conductivity. Beryllium is known there are considerable volume increases by helium accumulation. Therefore, we anticipate our suggested model can be applicable if it has been developed furthermore considering irradiation induced swelling

  12. Characterization of thermal and hydrodynamic properties for microencapsulated phase change slurry (MPCS)

    International Nuclear Information System (INIS)

    Chen, Lin; Wang, Ting; Zhao, Yan; Zhang, Xin-Rong

    2014-01-01

    Highlights: • Microencapsulated phase change slurry (MPCS) is reviewed and characterized for heat transfer and storage systems. • Basic formation, materials, properties are categorized and systematically analyzed. • Generalization and modelization of complex MPCS properties are made. • MPCS is identified to be one promising substitute in future energy systems. • Future research topics and applications are also specified. - Abstract: Microencapsulated phase change slurry (MPCS) is a new kind of multi-phase fluid that are proposed and utilized in heat transfer and heat storage systems. Different from traditional organic (paraffin or non-parafin) or inorganic phase change slurries, MPCS is able to maintain both high latent heat capacity and heat transfer rate under controlled volume changes and safe operation conditions. Consequently, in recent decade, MPCS has been widely proposed and tested in textile, building, cooling and heating, solar and thermal storage systems, etc. Based on those recent findings and application developments, characterizations of thermal and hydrodynamic properties for MPCS are made in this study. The basic objective of this paper is to summarize the features of MPCS properties and the establishment of models for MPCS properties and morphologies. The review and analysis are based on recent representative experimental studies, which are categorized into: properties, heat transfer characteristics, stability and applications. Due to the various materials and methods and carry fluids properties, no single model can cover the properties for all MPCS. In this study, each property is reviewed with its specific model and application regions. Basic trends are compared with other kinds of phase change materials. Finally, by investigating those results the future trends of MPCS are presented

  13. Assessment and optimization of thermal and fluidity properties of high strength concrete via genetic algorithm

    Directory of Open Access Journals (Sweden)

    Barış Şimşek

    2016-12-01

    Full Text Available This paper proposes a Response Surface Methodology (RSM based Genetic Algorithm (GA using MATLAB® to assess and optimize the thermal and fluidity of high strength concrete (HSC. The overall heat transfer coefficient, slump-spread flow and T50 time was defined as thermal and fluidity properties of high strength concrete. In addition to above mentioned properties, a 28-day compressive strength of HSC was also determined. Water to binder ratio, fine aggregate to total aggregate ratio and the percentage of super-plasticizer content was determined as effective factors on thermal and fluidity properties of HSC. GA based multi-objective optimization method was carried out by obtaining quadratic models using RSM. Having excessive or low ratio of water to binder provides lower overall heat transfer coefficient. Moreover, T50 time of high strength concrete decreased with the increasing of water to binder ratio and the percentage of superplasticizer content. Results show that RSM based GA is effective in determining optimal mixture ratios of HSC.

  14. National Standards Laboratory biennial report, 1971--1973

    Energy Technology Data Exchange (ETDEWEB)

    None

    1974-02-28

    This report describes the activities of the laboratory in: length interferometry; engineering metrology; photogrammetry; mass, volume, density, and pressure measurement: force, hardness, and materials testing machines; vibration; corrosion; time and frequency; acoustics; electrical standards; power frequency; high voltage; rf and microwave measurement; temperature measurement; optical radiometry; optics; dielectrics; magnetics; thermal and elastic properties of solids; electron transport in metals; low-energy collisions in gases; physics of the fluid state and high pressures; water vapor physics; viscometry; airglow; solar physics; and theoretical astrophysics. (DLC)

  15. Evaluation of thermal physical properties for fast reactor fuels. Melting point and thermal conductivities

    International Nuclear Information System (INIS)

    Kato, Masato; Morimoto, Kyoichi; Komeno, Akira; Nakamichi, Shinya; Kashimura, Motoaki; Abe, Tomoyuki; Uno, Hiroki; Ogasawara, Masahiro; Tamura, Tetsuya; Sugata, Hirotada; Sunaoshi, Takeo; Shibata, Kazuya

    2006-10-01

    Japan Atomic Energy Agency has developed a fast breeder reactor (FBR), and plutonium and uranium mixed oxide (MOX) having low density and 20-30%Pu content has used as a fuel of the FBR, Monju. In plutonium, Americium has been accumulated during long-term storage, and Am content will be increasing up to 2-3% in the MOX. It is essential to evaluate the influence of Am content on physical properties of MOX on the development of FBR in the future. In this study melting points and thermal conductivities which are important data on the fuel design were measured systematically in wide range of composition, and the effects of Am accumulated were evaluated. The solidus temperatures of MOX were measured as a function of Pu content, oxygen to metal ratio (O/M) and Am content using thermal arrest technique. The sample was sealed in a tungsten capsule in vacuum for measuring solidus temperature. In the measurements of MOX with Pu content of more than 30%, a rhenium inner capsule was used to prevent the reaction between MOX and tungsten. In the results, it was confirmed that the melting points of MOX decrease with as an increase of Pu content and increase slightly with a decrease of O/M ratio. The effect of Am content on the fuel design was negligible small in the range of Am content up to 3%. Thermal conductivities of MOX were evaluated from thermal diffusivity measured by laser flash method and heat capacity calculated by Neumann- Kopp's law. The thermal conductivity of MOX decreased slightly in the temperature of less than 1173K with increasing Am content. The effect of Am accumulated in long-term storage fuel was evaluated from melting points and thermal conductivities measured in this study. It is concluded that the increase of Am in the fuel barely affect the fuel design in the range of less than 3%Am content. (author)

  16. Structural and thermal properties of carboxylic acid functionalized polythiophenes

    Directory of Open Access Journals (Sweden)

    Ariane de França Mescoloto

    2014-01-01

    Full Text Available Polythiophenes functionalized with polar groups at the end of side-chain have emerged as an alternative method to obtain good compatibility between this class of conjugated polymers and electron acceptor compounds. The aim is to prevent phase segregation and to improve the efficiency of the polythiophene technological devices. However, homopolymers synthesized from thiophene rings with high polar groups at the end of the side-chain, such as hydroxyl and carboxylic acid groups, are poorly soluble in common volatile organic solvents. We report on a systematic preparation of copolymers of 3-hexylthiophene (HT and thiophene-3-acetic acid (TAA, using different feed ratios. The chemical structures of the copolymers were confirmed by FTIR and ¹H-NMR. The TAA content in these copolymers were 33, 38 and 54 mol %. HPSEC results did not show any remarkable correlation with TAA contents in the copolymers. In contrast, the thermal analyses showed a decrease in the thermal stability and an increase in rigidity of their backbones, for the copolymers with high amounts of TAA. The solubility and optical property of copolymers were also related to the TAA contents. Thus, the properties of these copolymers can be modulated by a simple control of feed ratio of TAA in the copolymerization.

  17. Simulation studies on structural and thermal properties of alkane thiol capped gold nanoparticles.

    Science.gov (United States)

    Devi, J Meena

    2017-06-01

    The structural and thermal properties of the passivated gold nanoparticles were explored employing molecular dynamics simulation for the different surface coverage densities of the self-assembled monolayer (SAM) of alkane thiol. The structural properties of the monolayer protected gold nanoparticles such us overall shape, organization and conformation of the capping alkane thiol chains were found to be influenced by the capping density. The structural order of the thiol capped gold nanoparticles enhances with the increase in the surface coverage density. The specific heat capacity of the alkane thiol capped gold nanoparticles was found to increase linearly with the thiol coverage density. This may be attributed to the enhancement in the lattice vibrational energy. The present simulation results suggest, that the structural and thermal properties of the alkane thiol capped gold nanoparticles may be modified by the suitable selection of the SAM coverage density. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. First principles study of electronic, elastic and thermal properties of lutetium intermetallics

    International Nuclear Information System (INIS)

    Pagare, Gitanjali; Chouhan, Sunil Singh; Soni, Pooja; Sanyal, S.P.; Rajagopalan, M.

    2011-01-01

    In the present work, the electronic, elastic and thermal properties of lutetium intermetallics LuX have been studied theoretically by using first principles calculations based on density functional theory (DFT) with the generalized gradient approximation (GCA)

  19. Ultrasonication effects on thermal and rheological properties of carbon nanotube suspensions.

    Science.gov (United States)

    Ruan, Binglu; Jacobi, Anthony M

    2012-02-14

    The preparation of nanofluids is very important to their thermophysical properties. Nanofluids with the same nanoparticles and base fluids can behave differently due to different nanofluid preparation methods. The agglomerate sizes in nanofluids can significantly impact the thermal conductivity and viscosity of nanofluids and lead to a different heat transfer performance. Ultrasonication is a common way to break up agglomerates and promote dispersion of nanoparticles into base fluids. However, research reports of sonication effects on nanofluid properties are limited in the open literature. In this work, sonication effects on thermal conductivity and viscosity of carbon nanotubes (0.5 wt%) in an ethylene glycol-based nanofluid are investigated. The corresponding effects on the agglomerate sizes and the carbon nanotube lengths are observed. It is found that with an increased sonication time/energy, the thermal conductivity of the nanofluids increases nonlinearly, with the maximum enhancement of 23% at sonication time of 1,355 min. However, the viscosity of nanofluids increases to the maximum at sonication time of 40 min, then decreases, finally approaching the viscosity of the pure base fluid at a sonication time of 1,355 min. It is also observed that the sonication process not only reduces the agglomerate sizes but also decreases the length of carbon nanotubes. Over the current experimental range, the reduction in agglomerate size is more significant than the reduction of the carbon nanotube length. Hence, the maximum thermal conductivity enhancement and minimum viscosity increase are obtained using a lengthy sonication, which may have implications on application.

  20. Effect of ZnO on the Thermal Properties of Tellurite Glass

    Directory of Open Access Journals (Sweden)

    H. A. A. Sidek

    2013-01-01

    Full Text Available Systematic series of binary zinc tellurite glasses in the form (ZnOx(TeO2 (where x=0 to 0.4 with an interval of 0.05 mole fraction have been successfully prepared via conventional melt cast-quenching technique. Their density was determined by Archimedes method with acetone as buoyant liquid. The thermal expansion coefficient of each zinc tellurite glasses was measured using L75D1250 dilatometer, while their glass transition temperature (Tg was determined by the SETARAM Labsys DTA/6 differential thermogravimetric analysis at a heating rate of 20 K min−1. The acoustic Debye temperature and the softening temperature (Ts were estimated based on the longitudinal (VL and shear ultrasonic (Vs wave velocities propagated in each glass sample. For ultrasonic velocity measurement of the glass sample, MATEC MBS 8000 Ultrasonic Data Acquisition System was used. All measurements were taken at 10 MHz frequency and at room temperature. All the thermal properties of such binary tellurite glasses were measured as a function of ZnO composition. The composition dependence was discussed in terms of ZnO modifiers that were expected to change the thermal properties of tellurite glasses. Experimental results show their density, and the thermal expansion coefficient increases as more ZnO content is added to the tellurite glass network, while their glass transition, Debye temperature, and the softening temperature decrease due to a change in the coordination number (CN of the network forming atoms and the destruction of the network structure brought about by the formation of some nonbridging oxygen (NBO atoms.

  1. Temperature dependence of thermal properties of Ag8In14Sb55Te23 phase-change memory materials

    International Nuclear Information System (INIS)

    Jiao, Xinbing; Gan, Fuxi; Wei, Jingsong; Xiao, Mufei

    2009-01-01

    The dependence of thermal properties of Ag 8 In 14 Sb 55 Te 23 phase-change memory materials in crystalline and amorphous states on temperature was measured and analyzed. The results show that in the crystalline state, the thermal properties monotonically decrease with the temperature and present obvious crystalline semiconductor characteristics. The heat capacity, thermal diffusivity, and thermal conductivity decrease from 0.35 J/gK, 1.85 mm 2 /s, and 4.0 W/mK at 300 K to 0.025 J/gK, 1.475 mm 2 /s, and 0.25 W/mK at 600 K, respectively. In the amorphous state, while the dependence of thermal properties on temperature does not present significant changes, the materials retain the glass-like thermal characteristics. Within the temperature range from 320 K to 440 K, the heat capacity fluctuates between 0.27 J/gK and 0.075 J/gK, the thermal diffusivity basically maintains at 0.525 mm 2 /s, and the thermal conductivity decreases from 1.02 W/mK at 320 K to 0.2 W/mK at 440 K. Whether in the crystalline or amorphous state, Ag 8 In 14 Sb 55 Te 23 are more thermally active than Ge 2 Sb 2 Te 5 , that is, the Ag 8 In 14 Sb 55 Te 23 composites bear stronger thermal conduction and diffusion than the Ge 2 Sb 2 Te 5 phase-change memory materials. (orig.)

  2. Effect of Microstructure on the Thermal Properties of Sintered Iron-copper Composites

    OpenAIRE

    Ugarteche, Caroline Velasques; Furlan, Kaline Pagnan; Pereira, Rafaela do Vale; Trindade, Gabriel; Binder, Roberto; Binder, Cristiano; Klein, Aloisio Nelmo

    2015-01-01

    Copper is a well know material for use as heat sink or heat exchanger. However, copper has a considerable low tensile strength and temperature limit. A material that has a good thermal conductivity, low cost, but also resistance is the desired. Effects of copper on the sintering and thermal properties of iron-copper composites produced by powder metallurgy and Fe on copper-iron composites have been investigated. Copper and iron were varied from 20 to 80 vol.% in the samples, alternating the c...

  3. Thermal effects of variable material properties and metamorphic reactions in a three-component subducting slab

    DEFF Research Database (Denmark)

    Chemia, Zurab; Dolejš, David; Steinle-Neumann, Gerd

    2015-01-01

    We explore the effects of variable material properties, phase transformations, and metamorphic devolatilization reactions on the thermal structure of a subducting slab using thermodynamic phase equilibrium calculations combined with a thermal evolution model. The subducting slab is divided...... into three layers consisting of oceanic sediments, altered oceanic crust, and partially serpentinized or anhydrous harzburgite. Solid-fluid equilibria and material properties are computed for each layer individually to illustrate distinct thermal consequences when chemical and mechanical homogenization...... indicate that subducting sediments and oceanic crust warm by 40 and 70°C, respectively, before the effect of wedge convection and heating is encountered at 1.7 GPa. Retention of fluid in the slab pore space plays a negligible role in oceanic crust and serpentinized peridotites. By contrast, the large...

  4. Linear analysis using secants for materials with temperature dependent nonlinear elastic modulus and thermal expansion properties

    Science.gov (United States)

    Pepi, John W.

    2017-08-01

    Thermally induced stress is readily calculated for linear elastic material properties using Hooke's law in which, for situations where expansion is constrained, stress is proportional to the product of the material elastic modulus and its thermal strain. When material behavior is nonlinear, one needs to make use of nonlinear theory. However, we can avoid that complexity in some situations. For situations in which both elastic modulus and coefficient of thermal expansion vary with temperature, solutions can be formulated using secant properties. A theoretical approach is thus presented to calculate stresses for nonlinear, neo-Hookean, materials. This is important for high acuity optical systems undergoing large temperature extremes.

  5. Magnetic Properties Studies on Thermal Aged Fe-Cu Alloys for the Simulation of Radiation Damage

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C. K.; Kishore, M.B.; Park, D. G. [KAERI, Daejeon (Korea, Republic of); Son, De Rac. [Hannam University, Daejeon (Korea, Republic of)

    2016-05-15

    We evaluated the changes in magnetic properties due to cold rolling and thermal ageing of a Fe-1%Cu model alloy in this study. Initially, the alloy was 10% cold rolled, and isothermally aged at 400 .deg. C for 1, 10, 100 and 1000 hr. The samples were prepared at various thermal aging conditions and all the conditions were interpreted. The hysteresis loops, Magnetic Barkhausen noise (BN). The change of magnetic properties can be interpreted in terms of the domain wall motion and dislocation dynamics associated with copper rich precipitates (CRPs).The results were interpreted in terms of ageing time dependence of the precipitates evolution such as the volume fraction and size distribution. In order to evaluate the radiation embrittlement of RPV steel, A Cold rolled Fe-Cu model Alloy was prepared, The prepared samples were thermally aged by annealing at 400 .deg. C for various times, the magnetic properties of the annealed samples were measured, The Barkhausen noise and BH Loop shows a considerable trend corresponding to the Ageing time. The magnetic properties were interpreted and correlated to the CRPs formed through annealing process.

  6. Sugar Profile, Mineral Content, and Rheological and Thermal Properties of an Isomerized Sweet Potato Starch Syrup

    OpenAIRE

    Dominque, Brunson; Gichuhi, Peter N.; Rangari, Vijay; Bovell-Benjamin, Adelia C.

    2013-01-01

    Currently, corn is used to produce more than 85% of the world's high fructose syrup (HFS). There is a search for alternative HFS substrates because of increased food demand and shrinking economies, especially in the developing world. The sweet potato is a feasible, alternative raw material. This study isomerized a high glucose sweet potato starch syrup (SPSS) and determined its sugar profile, mineral content, and rheological and thermal properties. Rheological and thermal properties were meas...

  7. The magnetic-nanofluid heat pipe with superior thermal properties through magnetic enhancement

    Science.gov (United States)

    2012-01-01

    This study developed a magnetic-nanofluid (MNF) heat pipe (MNFHP) with magnetically enhanced thermal properties. Its main characteristic was additional porous iron nozzle in the evaporator and the condenser to form a unique flowing pattern of MNF slug and vapor, and to magnetically shield the magnet attraction on MNF flowing. The results showed that an optimal thermal conductivity exists in the applied field of 200 Oe. Furthermore, the minor thermal performance of MNF at the condenser limited the thermal conductivity of the entire MNFHP, which was 1.6 times greater than that filled with water for the input power of 60 W. The feasibilities of an MNFHP with the magnetically enhanced heat transfer and the ability of vertical operation were proved for both a promising heat-dissipation device and the energy architecture integrated with an additional energy system. PMID:22716909

  8. Gamma irradiation effects on the thermal, optical and structural properties of Cr-39 nuclear track detector

    International Nuclear Information System (INIS)

    Nouh, S.A.; Said, A.F.; Atta, M.R.; EL-Mellegy, W.M.; EL-Meniawi, S.

    2006-01-01

    A study of the effect of gamma irradiation on the thermal, optical and structural properties of CR-39 diglycol carbonate solid state nuclear track detector (SSNTD) has been carried out. Samples from CR-39 polymer were irradiated with gamma doses at levels between 20 and 300 KGy. Non-isothermal studies were carried out using thermo-gravimetry (TG), differential thermo-gravimetry (DTG) and differential thermal analysis (DTA) to obtain the activation energy of decomposition and the transition temperatures for the non-irradiated and irradiated CR-39 samples. In addition, optical and structural property studies were performed on non-irradiated and irradiated CR-39 samples using refractive index and X-ray diffraction measurements. The variation of onset temperature of decomposition (To) thermal activation energy of decomposition (Ea) melting temperature (Tm) refractive index (n) and the mass fraction of the amorphous phase with the gamma dose were studied. It was found that many changes in the thermal, optical and structural properties of the CR-39 polymer could be produced by gamma irradiation via the degradation and cross linking mechanisms. Also, the gamma dose gave an advantage for increasing the correlation between the thermal stability of CR-39 polymer and the bond formation created by the ionizing effect of gamma radiation

  9. Compositional dependence thermal and optical properties of a novel germanate glass

    International Nuclear Information System (INIS)

    El-Rabaie, S.; Taha, T.A.; Higazy, A.A.

    2014-01-01

    A series of zinc lithium germanate glasses of the composition (45−x)Li 2 O–xZnO–55GeO 2 have been synthesized via melt quenching technique. Dependencies of their thermal and optical properties on composition were investigated. It is found that the gradual replacement of Li 2 O by ZnO, decreases the glass transition temperature from 430 to 280 °C and increases the thermal stability (ΔT) of the studied glasses. The optical band gap E opt also decreases from 2.31 to 1.40 eV with increasing the mole content of ZnO

  10. Antimicrobial properties of uncapped silver nanoparticles synthesized by DC arc thermal plasma technique.

    Science.gov (United States)

    Shinde, Manish; Patil, Rajendra; Karmakar, Soumen; Bhoraskar, Sudha; Rane, Sunit; Gade, Wasudev; Amalnerkar, Dinesh

    2012-02-01

    We, herein, report the antimicrobial properties of uncapped silver nanoparticles for a Gram positive model organism, Bacillus subtilis. Uncapped silver nanoparticles have been prepared using less-explored DC arc thermal plasma technique by considering its large scale generation capability. It is observed that the resultant nanoparticles show size as well as optical property dependent antimicrobial effect.

  11. Complex evaluation of properties for some thermal insulating materials of NPP

    International Nuclear Information System (INIS)

    Yurchenko, V.G.; Nazarova, G.A.; Yakunichev, V.N.; Potulov, V.V.; Kazakova, K.A.

    1991-01-01

    The effects of the main operational factors (temperature, ionizing radiation, increased humidity) on some most widely applied fibrous materials are investigated. The samples were irradiated by 60 Co gamma photons at the PKhM-gamma-20 device in air at temperature of 40±1 deg C in order to analyze the radiation resistance of thermal insulating materials. The analysis and generalization of the results of laboratory tests give an opportunity to make the following conclusions. The thermal insulation articles and constructions made of superfine basalt fiber may be used in the zones of rigorous regime. The superfine glass fibers (GF) are recommended to be used for equipment and pipeline shielding in the zones of rigorous control only as a part of multilayer insulation as the second or next layers and only in places where leaks are impossible

  12. Thermal site descriptive model. A strategy for the model development during site investigations - version 2

    International Nuclear Information System (INIS)

    Back, Paer-Erik; Sundberg, Jan

    2007-09-01

    This report presents a strategy for describing, predicting and visualising the thermal aspects of the site descriptive model. The strategy is an updated version of an earlier strategy applied in all SDM versions during the initial site investigation phase at the Forsmark and Oskarshamn areas. The previous methodology for thermal modelling did not take the spatial correlation fully into account during simulation. The result was that the variability of thermal conductivity in the rock mass was not sufficiently well described. Experience from earlier thermal SDMs indicated that development of the methodology was required in order describe the spatial distribution of thermal conductivity in the rock mass in a sufficiently reliable way, taking both variability within rock types and between rock types into account. A good description of the thermal conductivity distribution is especially important for the lower tail. This tail is important for the design of a repository because it affects the canister spacing. The presented approach is developed to be used for final SDM regarding thermal properties, primarily thermal conductivity. Specific objectives for the strategy of thermal stochastic modelling are: Description: statistical description of the thermal conductivity of a rock domain. Prediction: prediction of thermal conductivity in a specific rock volume. Visualisation: visualisation of the spatial distribution of thermal conductivity. The thermal site descriptive model should include the temperature distribution and thermal properties of the rock mass. The temperature is the result of the thermal processes in the repository area. Determination of thermal transport properties can be made using different methods, such as laboratory investigations, field measurements, modelling from mineralogical composition and distribution, modelling from density logging and modelling from temperature logging. The different types of data represent different scales, which has to be

  13. Thermal site descriptive model. A strategy for the model development during site investigations - version 2

    Energy Technology Data Exchange (ETDEWEB)

    Back, Paer-Erik; Sundberg, Jan [Geo Innova AB (Sweden)

    2007-09-15

    This report presents a strategy for describing, predicting and visualising the thermal aspects of the site descriptive model. The strategy is an updated version of an earlier strategy applied in all SDM versions during the initial site investigation phase at the Forsmark and Oskarshamn areas. The previous methodology for thermal modelling did not take the spatial correlation fully into account during simulation. The result was that the variability of thermal conductivity in the rock mass was not sufficiently well described. Experience from earlier thermal SDMs indicated that development of the methodology was required in order describe the spatial distribution of thermal conductivity in the rock mass in a sufficiently reliable way, taking both variability within rock types and between rock types into account. A good description of the thermal conductivity distribution is especially important for the lower tail. This tail is important for the design of a repository because it affects the canister spacing. The presented approach is developed to be used for final SDM regarding thermal properties, primarily thermal conductivity. Specific objectives for the strategy of thermal stochastic modelling are: Description: statistical description of the thermal conductivity of a rock domain. Prediction: prediction of thermal conductivity in a specific rock volume. Visualisation: visualisation of the spatial distribution of thermal conductivity. The thermal site descriptive model should include the temperature distribution and thermal properties of the rock mass. The temperature is the result of the thermal processes in the repository area. Determination of thermal transport properties can be made using different methods, such as laboratory investigations, field measurements, modelling from mineralogical composition and distribution, modelling from density logging and modelling from temperature logging. The different types of data represent different scales, which has to be

  14. Study on properties and testing methods of thermo-responsive cementing system for well cementing in heavy oil thermal recovery

    Science.gov (United States)

    Li, Lianjiang

    2017-08-01

    In this paper, thermo-responsive cement slurry system were being developed, the properties of conventional cement slurry, compressive strength high temperature of cement sheath, mechanical properties of cement sheath and thermal properties of cement sheath were being tested. Results were being used and simulated by Well-Life Software, Thermo-responsive cement slurry system can meet the requirements of heavy oil thermal recovery production. Mechanical and thermal properties of thermo-responsive cement sheath were being tested. Tensile fracture energy of the thermo-responsive cement sheath is larger than conventional cement. The heat absorption capacity of conventional cement sheath is larger than that of thermo-responsive cement sheath, this means more heat is needed for the unit mass once increasing 1.0 °C, which also indicates that thermo-responsive cement own good heat insulating and preservation effects. The heat conductivity coefficient and thermal expansion coefficient of thermo-responsive cement is less than and conventional cement, this means that thermo-responsive cement have good heat preservation and insulation effects with good thermal expansion stabilities.

  15. Constraints on Spin Axis and Thermal Properties of Asteroids in the WISE Catalog

    Science.gov (United States)

    MacLennan, Eric M.; Emery, J. P.

    2013-10-01

    It has widely been accepted that dynamical state of asteroids can strongly be influenced by radiation forces (e.g., Yarkovsky and YORP). Determination of an object’s thermal properties and spin state are a critical step towards understanding the effects of these forces. In this respect, observations of thermal flux emitted from the surfaces of asteroids are a powerful tool. The emission of flux is determined by the temperature distribution which is controlled by the thermal inertia, rotation rate, and spin axis orientation. By gathering data at multiple viewing geometries, the temperature distribution can be modeled accurately enough to separate the effects attributed to (some of) these parameters. Over the length of its mission, the Wide-Field Infrared Survey Explorer (WISE) observed many asteroids in two epochs (i.e., on either side of opposition) such that data for both morning and afternoon times were gathered. We have begun a project that employs a Thermophysical Model (TPM) in order to analyze these multi-epoch thermal observations with the goal of deriving the thermal properties and spin axis of a large number of asteroids. Here, we first investigate the validity and limits of our method on objects with a previously determined spin axis. Asteroid (413) Edburga has a published spin axis of λ = 202o, β = - 45o (ecliptic longitude and latitude, respectively) using the lightcurve inversion method. With our technique, we estimate a solution consistent with the previous estimate. Applying our TPM to WISE multi-epoch thermal observations of (155) Scylla (no known spin axis estimate), we also place estimates for the ecliptic longitude and latitude of its spin axis. Analysis of multi-epoch thermal data enables determination of spin axis orientation without knowing the rotation period, in contrast to the lightcurve inversion method. This is due to the coupling of thermal inertia and rotation rate in determining the longitudinal distribution of temperature. Their

  16. Constraining Non-thermal and Thermal properties of Dark Matter

    Directory of Open Access Journals (Sweden)

    Bhupal eDev

    2014-05-01

    Full Text Available We describe the evolution of Dark Matter (DM abundance from the very onset of its creation from inflaton decay under the assumption of an instantaneous reheating. Based on the initial conditions such as the inflaton mass and its decay branching ratio to the DM species, the reheating temperature, and the mass and interaction rate of the DM with the thermal bath, the DM particles can either thermalize (fully/partially with the primordial bath or remain non-thermal throughout their evolution history. In the thermal case, the final abundance is set by the standard freeze-out mechanism for large annihilation rates, irrespective of the initial conditions. For smaller annihilation rates, it can be set by the freeze-in mechanism which also does not depend on the initial abundance, provided it is small to begin with. For even smaller interaction rates, the DM decouples while being non-thermal, and the relic abundance will be essentially set by the initial conditions. We put model-independent constraints on the DM mass and annihilation rate from over-abundance by exactly solving the relevant Boltzmann equations, and identify the thermal freeze-out, freeze-in and non-thermal regions of the allowed parameter space. We highlight a generic fact that inflaton decay to DM inevitably leads to an overclosure of the Universe for a large range of DM parameter space, and thus poses a stringent constraint that must be taken into account while constructing models of DM. For the thermal DM region, we also show the complementary constraints from indirect DM search experiments, Big Bang Nucleosynthesis, Cosmic Microwave Background, Planck measurements, and theoretical limits due to the unitarity of S-matrix. For the non-thermal DM scenario, we show the allowed parameter space in terms of the inflaton and DM masses for a given reheating temperature, and compute the comoving free-streaming length to identify the hot, warm and cold DM regimes.

  17. On the spin saturation and thermal properties of nuclear matter

    International Nuclear Information System (INIS)

    Hassan, M.Y.M.; Ramadan, S.

    1983-12-01

    The binding energy and the incompressibility of nuclear matter with degree of spin saturation D is calculated using the Skyrme interaction and two forms of a velocity dependent effective potential. The effect of the degree of spin saturation D on the thermal properties of nuclear matter is also discussed. It is found that generally the pressure decreases with increasing D. (author)

  18. Lipophilic phytosterol derivatives: synthesis, thermal property and nanoemulsion behavior

    DEFF Research Database (Denmark)

    Panpipat, Worawan; Xu, Xuebing; Guo, Zheng

    Phytosterols and their esters have been reported as a cholesterol lowering agent in human. However, natural phytosterols have a low solubility in both water and fat resulting in a poor absorption in intestine. To improve the intestinal absorption and bioavailability of phytosterols, conversion...... of phytosterols into enzyme-liable lipophilic derivatives, such as fatty acid esters was one of the possible strategies. Differences in molecular structures of modified phytosterols may result in the differences in their thermal and micelling behaviors. Therefore, the objectives of this study were to improve...... the productive yield of a series of -sitosteryl fatty acid esters (C2-C18) and to investigate the thermal property and nano-emulsion behaviors of those compounds. This work reported a novel approach to synthesize phytosterol (-sitosterol as a model) fatty acid ester by employing Candida antarctica lipase...

  19. The effect of linear imperfection in [001] direction on the thermal properties of silver crystal

    Directory of Open Access Journals (Sweden)

    J Davoodi

    2013-09-01

    Full Text Available  The aim of this investigation was to calculate the thermal properties of silver crystal in the presence of linear imperfection. The simulations were performed by molecular dynamics simulation technique in NPT as well as NVT ensemble based on quantum Sutton-Chen many body potential. The thermal properties including cohesive energy, melting temperature, isobaric heat capacity and thermal expansion of imperfect silver crystal were calculated and compared to those of the perfect crystal. Moreover, the quantities such as radial distribution function, order parameter and lindemann index were calculated in order to obtain information on crystal structure and disorder in atoms. All calculations were done both with liner imperfection in [001] direction and without imperfection at different temperature. The simulation results show that cohesive energy, linear thermal expansion coefficient increase and melting temperature, latent heat of fusion decrease with increasing linear imperfection. Also, the results show that linear imperfection has no effect on the heat capacity.

  20. Rheological and thermal properties of suspensions of microcapsules containing phase change materials.

    Science.gov (United States)

    Cao, Vinh Duy; Salas-Bringas, Carlos; Schüller, Reidar Barfod; Szczotok, Anna M; Hiorth, Marianne; Carmona, Manuel; Rodriguez, Juan F; Kjøniksen, Anna-Lena

    2018-01-01

    The thermal and rheological properties of suspensions of microencapsulated phase change materials (MPCM) in glycerol were investigated. When the microcapsule concentration is raised, the heat storage capacity of the suspensions becomes higher and a slight decline in the thermal conductivity of the suspensions is observed. The temperature-dependent shear-thinning behaviour of the suspensions was found to be strongly affected by non-encapsulated phase change materials (PCM). Accordingly, the rheological properties of the MPCM suspensions could be described by the Cross model below the PCM melting point while a power law model best described the data above the PCM melting point. The MPCM suspensions are interesting for energy storage and heat transfer applications. However, the non-encapsulated PCM contributes to the agglomeration of the microcapsules, which can lead to higher pumping consumption and clogging of piping systems.

  1. Uniaxial Negative Thermal Expansion and Mechanical Properties of a Zinc-Formate Framework

    Directory of Open Access Journals (Sweden)

    Hongqiang Gao

    2017-02-01

    Full Text Available The thermal expansion behavior of a metal-formate framework, Zn(HCOO2·2(H2O (1, has been systematically studied via variable temperature single-crystal X-ray diffraction. Our results demonstrate that this formate exhibits significant negative thermal expansion (NTE, −26(2 MK−1 along its c-axis. Detailed structural analyses reveal that the large NTE response is attributed to the ‘hinge-strut’ like framework motion. In addition, the fundamental mechanical properties of framework 1 have been explored via nanoindentation experiments. The measured elastic modulus and hardness properties on the (00-2/(100/(110 facets are 35.5/35.0/27.1 and 2.04/1.83/0.47 GPa, respectively. The stiffness and hardness anisotropy can be correlated well with the underlying framework structure, like its thermoelastic behavior.

  2. Prediction of Thermal Properties of Sweet Sorghum Bagasse as a Function of Moisture Content Using Artificial Neural Networks and Regression Models

    Directory of Open Access Journals (Sweden)

    Gosukonda Ramana

    2017-06-01

    Full Text Available Artificial neural networks (ANN and traditional regression models were developed for prediction of thermal properties of sweet sorghum bagasse as a function of moisture content and room temperature. Predictions were made for three thermal properties: 1 thermal conductivity, 2 volumetric specific heat, and 3 thermal diffusivity. Each thermal property had five levels of moisture content (8.52%, 12.93%, 18.94%, 24.63%, and 28.62%, w. b. and room temperature as inputs. Data were sub-partitioned for training, testing, and validation of models. Backpropagation (BP and Kalman Filter (KF learning algorithms were employed to develop nonparametric models between input and output data sets. Statistical indices including correlation coefficient (R between actual and predicted outputs were produced for selecting the suitable models. Prediction plots for thermal properties indicated that the ANN models had better accuracy from unseen patterns as compared to regression models. In general, ANN models were able to strongly generalize and interpolate unseen patterns within the domain of training.

  3. Investigation of Thermal Properties of High-Density Polyethylene/Aluminum Nanocomposites by Photothermal Infrared Radiometry

    Science.gov (United States)

    Koca, H. D.; Evgin, T.; Horny, N.; Chirtoc, M.; Turgut, A.; Tavman, I. H.

    2017-12-01

    In this study, thermal properties of high-density polyethylene (HDPE) filled with nanosized Al particles (80 nm) were investigated. Samples were prepared using melt mixing method up to filler volume fraction of 29 %, followed by compression molding. By using modulated photothermal radiometry (PTR) technique, thermal diffusivity and thermal effusivity were obtained. The effective thermal conductivity of nanocomposites was calculated directly from PTR measurements and from the measurements of density, specific heat capacity (by differential scanning calorimetry) and thermal diffusivity (obtained from PTR signal amplitude and phase). It is concluded that the thermal conductivity of HDPE composites increases with increasing Al fraction and the highest effective thermal conductivity enhancement of 205 % is achieved at a filler volume fraction of 29 %. The obtained results were compared with the theoretical models and experimental data given in the literature. The results demonstrate that Agari and Uno, and Cheng and Vachon models can predict well the thermal conductivity of HDPE/Al nanocomposites in the whole range of Al fractions.

  4. Structural, optical, opto-thermal and thermal properties of ZnS-PVA nanofluids synthesized through a radiolytic approach.

    Science.gov (United States)

    Kharazmi, Alireza; Faraji, Nastaran; Mat Hussin, Roslina; Saion, Elias; Yunus, W Mahmood Mat; Behzad, Kasra

    2015-01-01

    This work describes a fast, clean and low-cost approach to synthesize ZnS-PVA nanofluids consisting of ZnS nanoparticles homogeneously distributed in a PVA solution. The ZnS nanoparticles were formed by the electrostatic force between zinc and sulfur ions induced by gamma irradiation at a dose range from 10 to 50 kGy. Several experimental characterizations were conducted to investigate the physical and chemical properties of the samples. Fourier transform infrared spectroscopy (FTIR) was used to determine the chemical structure and bonding conditions of the final products, transmission electron microscopy (TEM) for determining the shape morphology and average particle size, powder X-ray diffraction (XRD) for confirming the formation and crystalline structure of ZnS nanoparticles, UV-visible spectroscopy for measuring the electronic absorption characteristics, transient hot wire (THW) and photoacoustic measurements for measuring the thermal conductivity and thermal effusivity of the samples, from which, for the first time, the values of specific heat and thermal diffusivity of the samples were then calculated.

  5. Fabrication of polylactic acid/hydroxyapatite/graphene oxide composite and their thermal stability, hydrophobic and mechanical properties

    Directory of Open Access Journals (Sweden)

    Ming Gong

    2017-06-01

    Full Text Available A series of polylactic acid/hydroxyapatite/graphene oxide composite (PLA/HA/GO were fabricated via solution blending and casting method using N,N-dimethyl-formamide (DMF and CH2Cl2 as mutual solvents. The physicochemical properties of the resulting composites were characterized by means of FT-IR, SEM, TEM, Raman spectra, XRD and N2-physisorption. Particularly, the thermal stabilities, hydrophobic and mechanical properties of PLA/HA/GO composites were systematically investigated. The influences of GO content on thermal stabilities, hydrophobic and mechanical properties of the composites were also evaluated. The results showed that the addition of GO and HA not only improved the thermal stability of PLA, but also improved the hydrophobic property of PLA-based composites. By compared with the PLA/HA/GO composite, the tensile strength of pristine PLA is slight high. The tensile strength and hardness of PLA/HA/GO composites increased with the increase of GO content. The obtained PLA/HA/GO composite may be a promising material for load-bearing orthopedic implants.

  6. Laboratory studies of the corrosion and mechanical properties of titanium grade-12 under WIPP repository conditions

    International Nuclear Information System (INIS)

    Sorensen, N.R.

    1990-01-01

    The author reviews laboratory work done at the Sandia Laboratories on the properties of titanium grade 12. The effect of gamma radiation on corrosion and mechanical properties has been investigated; no real effect has been detected on corrosion rate, Charpy impact energy, or tensile properties at 90 degrees and 10 4 rad/h. No structural changes are evident under examination by SEM or TEM. There is also no evidence of crevice corrosion after five years of exposure. The effect of radiation on hydrogen uptake was also investigated. Radiation appears to reduce the extent of uptake. The microstructure of titanium-12 changes with the addition of hydrogen to a structure with alternating layers of alpha and beta phase. A decrease in mechanical properties is associated with this change

  7. Creep properties of a thermally grown alumina

    Energy Technology Data Exchange (ETDEWEB)

    Kang, K.J. [Department of Mechanical Engineering, Chonnam National University, Kwangju 500-757 (Korea, Republic of)], E-mail: kjkang@chonnam.ac.kr; Mercer, C. [Materials Department, University of California, Santa Barbara, CA 93106-5050 (United States)

    2008-04-15

    A unique test system has been developed to measure creep properties of actual thermally grown oxides (TGO) formed on a metal foil. The thickness of TGO, load and displacement can be monitored in situ at high temperature. Two batches of FeCrAlY alloys which differ from each other in contents of yttrium and titanium were selected as the {alpha}-Al{sub 2}O{sub 3} TGO forming materials. The creep tests were performed on {alpha}-Al{sub 2}O{sub 3} of thickness 1-4 {mu}m, thermally grown at 1200 deg. C in air. The strength of the substrate was found to be negligible, provided that the TGO and substrate thickness satisfy: h{sub TGO} > 1 {mu}m and H{sub sub} {<=} 400 {mu}m. The steady-state creep results for all four TGO thicknesses obtained on batch I reside within a narrow range, characterized by a parabolic creep relation. It is nevertheless clear that the steady-state creep rates vary with TGO thickness: decreasing as the thickness increases. For batch II, the steady-state creep rates are higher and now influenced more significantly by TGO thickness. In comparison with previous results of the creep properties for bulk polycrystalline {alpha}-Al{sub 2}O{sub 3} at a grain size of {approx}2 {mu}m, the creep rates for the TGO were apparently higher, but both were significantly affected by yttrium content. The higher creep rate and dependency on the TGO thickness led to a hypothesis that the deformation of the TGO under tensile stress at high temperature was not a result of typical creep mechanisms such as diffusion of vacancies or intra-granular motion of dislocations, but a result of inter-grain growth of TGO. Results also indicate that the amount of yttrium may influence the growth strain as well as the creep rate.

  8. Thermal, emulsifying and rheological properties of polysaccharides sequentially extracted from Vaccinium bracteatum Thunb leaves.

    Science.gov (United States)

    Xu, Qi-Xin; Shi, Jun-Jun; Zhang, Jian-Guo; Li, Ling; Jiang, Li; Wei, Zhao-Jun

    2016-12-01

    Plant polysaccharides are widely used in food industry as thickening and gelling agents and these attributes largely depend on their thermal, emulsifying and rheological properties. As known, the extraction methods always bring about the diversification of property and functions of polysaccharides. Thus, the Vaccinium bracteatum Thunb leaves polysaccharides (VBTLP) were sequentially extracted using hot buffer (HBSS), chelating agent (CHSS), dilute alkaline (DASS) and concentrated alkaline (CASS). The thermal, emulsifying and rheological properties of VBTLP were investigated in the present study. Within the range of 20-225°C, CHSS showed the highest peak temperature, whereas HBSS displayed the highest endothermic enthalpy and highest emulsifying activity, while, CASS showed the longest emulsifying stability. The VBTLP solutions exhibited non-Newtonian shear-thinning behavior within the concentrations of 0.6-2.5%. The apparent viscosity of VBTLP solution decreased under following conditions: acidic pH (4.0), alkaline pH (10.0), in the presence of Ca 2+ and at high temperature, while it increased in the presence of Na + and at freezing conditions. The modulus G' and G″ of VBTLP solutions were increased with increasing oscillation frequency, and the crossover frequency shifted to lower values when the polysaccharide content increased. The above results of thermal, emulsifying and rheological properties of VBTLPs supplied the basis for V. bracteatum leaves in potential industrial applications of foods. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. IMPACT OF IRRADIATION AND THERMAL AGING ON DWPF SIMULATED SLUDGE PROPERTIES

    International Nuclear Information System (INIS)

    Eibling, R; Michael Stone, M

    2006-01-01

    The research and development programs in support of the Defense Waste Processing Facility (DWPF) and other high-level waste vitrification processes require the use of both nonradioactive waste simulants and actual waste samples. While actual waste samples are the ideal materials to study, acquiring large quantities of actual waste is difficult and expensive. Tests utilizing actual high-level waste require the use of expensive shielded cells facilities to provide sufficient shielding for the researchers. Nonradioactive waste simulants have been used for laboratory testing, pilot-scale testing and full-scale integrated facility testing. These waste simulants were designed to reproduce the chemical and, if possible, the physical properties of the actual high-level waste. This technical report documents a study on the impact of irradiating a Sludge Batch 3 (SB3) simulant and of additional tests on aging a SB3 simulant by additional thermal processing. Prior simulant development studies examined methods of producing sludge and supernate simulants and processes that could be used to alter the physical properties of the simulant to more accurately mimic the properties of actual waste. Development of a precipitated sludge simulant for the River Protection Project (RPP) demonstrated that the application of heat for a period of time could significantly alter the rheology of the sludge simulant. The RPP precipitated simulant used distillation to concentrate the sludge solids and produced a reduction in sludge yield stress of up to 80% compared to the initial sludge properties. Observations at that time suggested that a substantial fraction of the iron hydroxide had converted to the oxide during the distillation. DWPF sludge simulant studies showed a much smaller reduction in yield stress (∼10%), demonstrated the impact of shear on particle size, and showed that smaller particle sizes yielded higher yield stress products. The current study documented in this report focuses

  10. Montmorillonite/poly(urethane-siloxane) nanocomposites: morphological, thermal, mechanical and surface properties

    Czech Academy of Sciences Publication Activity Database

    Stefanović, I. S.; Špírková, Milena; Ostojić, S.; Stefanov, P.; Pavlović, V. B.; Pergal, M. V.

    2017-01-01

    Roč. 149, 1 December (2017), s. 136-146 ISSN 0169-1317 R&D Projects: GA ČR(CZ) GA13-06700S Institutional support: RVO:61389013 Keywords : polyurethane nanocomposites * thermal properties * clay nano-fillers Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 3.101, year: 2016

  11. Thermal and physiochemical properties of pellets with power aims made of sawmill residual product

    International Nuclear Information System (INIS)

    Casanova Treto, Pedro; Solis, Kattia; Carrillo, Tonny

    2017-01-01

    Sawmill residual product of Pylon (Hyeronima alchorneoides) and Eucalyptus (Eucalyptus spp) species was used to produce pellets under different conditions of densification. Experimental equipment was used to determine the thermal conductivity, thermal diffusivity and specific heat. Physicochemical properties of the pellets obtained under different conditions of densification, such as ash content and calorific value were determined. The content of nitrogen, chlorine and sulfur present in the material used to produce the pellets was estimated. Thermal conductivity values were determined between 0,253 W/m·K and 0,279 W/m·K; 1,748 m2 /s and 2,314 m2 /s for the thermal diffusivity, and in the case of specific heat were determined values between 3,019 kJ/kg·K and 2,183 kJ/kg·K. The high heat values was between 18 907 kJ/kg and 18 960 kJ/kg. An ash content of 1,31% was determined on a dry basis. Finally, the content of nitrogen, chlorine and sulfur determined in the residual biomass used, corresponds to 0,1129%, 0,0592 % and 0,0317%, respectively. A direct relationship between increasing the bulk density of the pellets and the thermal properties was determined. The calorific value and the ash content had a negligible effect due to the treatments applied. The estimated content of N, Cl and S corresponds to that expected in the selected biomass. Comparison of the properties of the pellets produced under the conditions studied -densification, against regulations-, showed acceptable results, entering these in terms of different categories of quality. (author) [es

  12. Organisation of a laboratory of photographic dosimetry

    International Nuclear Information System (INIS)

    Soudain, Georges

    1961-01-01

    After a recall of the main properties of photographic dosimetry, the author describes the principle of this method, and comments the issue of chromatic sensitivity of photographic emulsions. He discusses the calibration process for gamma radiation, X rays, and thermal neutrons. He describes how fast neutron dosimetry is performed. In the next part, he describes the organisation of the photometry laboratory which has to prepare and distribute dosimeters, to collect and exploit them, and to prepare a publication of results. These different missions and tasks are described

  13. Nanodiamond particles/PVDF nanocomposite flexible films: thermal, mechanical and physical properties

    Science.gov (United States)

    Jaleh, Babak; Sodagar, Shima; Momeni, Amir; Jabbari, Ameneh

    2016-08-01

    Recently, polymer nanocomposites reinforced with nanoparticles have attracted a lot of attention due to their unique physical and mechanical properties. In this work, poly (vinylidene fluoride)/nanodiamond particles nanocomposite films were prepared by solution casting method with various nanodiamond particles contents. The samples were investigated by Fourier transform infrared spectroscopy and x-ray diffraction technique. The results revealed an obvious α to β-phase transformation compared to pure PVDF. The most (or the maximum) phase transformation from α to β-phase (>90%) was found for nanocomposite film with 8% wt nanodiamond particles. Scanning electron micrographs showed considerable decrease in the size of spherulitic crystal structure of PVDF with adding nanoparticles. The photoluminescence property of nanocomposite films was investigated by photoluminescence spectroscopy and the optical band gap value was calculated from the UV-visible absorption spectra. The results showed that after the incorporation of nanoparticles into PVDF, the value of optical band gap decreased. Thermal stability of samples was studied by thermogravimetric analysis. Due to an increase in the electroactive phase (β) percentage by adding nanoparticles, the resistance of samples to thermal degradation improved. The mechanical properties of samples were investigated by tensile test and hardness measurements. The elastic modulus and hardness of samples were enhanced by adding nanodiamond particles and elongation to fracture decreased.

  14. Study of an experimental methodology for thermal properties diagnostic of building envelop

    Science.gov (United States)

    Yang, Yingying; Sempy, Alain; Vogt Wu, Tingting; Sommier, Alain; Dumoulin, Jean; Batsale, Jean Christophe

    2017-04-01

    The building envelope plays a critical role in determining levels of comfort and building efficiency. Its real thermal properties characterization is of major interest to be able to diagnose energy efficiency performance of buildings (new construction and retrofitted existing old building). Research and development on a possible methodology for energy diagnostic of the building envelop is a hot topic and necessary trend. Many kinds of sensors and instruments are used for the studies. The application of infrared (IR) thermography in non-destructive evaluation has been widely employed for qualitative evaluations for building diagnostics; meanwhile, the IR thermography technology also has a large potentiality for the evaluation of the thermal characteristics of the building envelope. Some promising recent research studies have been carried out with such contactless measurement technique. Nevertheless, research efforts are still required for in situ measurements under natural environmental conditions. In order to develop new solutions for non-intrusive evaluation of local thermal performance, enabling quantitative assessment of thermal properties of buildings and materials, experiments were carried out on a multi-layer pratical scale wall fixed on a caisson placed in a climatic chamber. Six halogen lamps (1.5 kW for each lamp) placed in front of objective wall were used to emulate sunny conditions. The radiative heat flux emitted was monitored and modulated with time according to typical weather data set encountered in France. Both steady state and transient regime heat transfer were studied during these experiments. Contact sensors (thermocouples, heat flux meters, Peltier sensors) and non-contact sensors (thermal IR camera, pyranometer) were used to measure the temperatures and heat flux density evolution. It has to be noticed that the Peltier sensors have been tuned and used with a specific processing to set them compliant for heat flux density measurements. The

  15. Anomalous thermal property behaviour of uranium at low temperatures

    International Nuclear Information System (INIS)

    Sandenaw, T.A.

    1975-01-01

    Low temperature heat capacity curves are presented for polycrystalline 235 U and 238 U metals in different microstructural states and of different purities. Thermal conductivity versus temperature curves are shown for low-purity, polycrystalline 238 U in the temperature range between approximately 80 and 373 0 K for metal having undergone varied fabrication procedures. Published information suggests that there will be no structural modification in very pure uranium below room temperature. The influence of impurities on low temperature transitions may be through their effects on dislocation formation. Thermal conductivity and heat capacity runs started at approximately 80 0 K, after holding specimens at the temperature of boiling liquid nitrogen, do not give results which match up with runs started below 36 to 43 0 K. Result of measurements started at approximately 80 0 K indicate that an ordering mechanism is predominating, with microstructure rather than purity being the important factor. This can be explained if ordering at approximately 80 0 K is through lattice imperfections remaining from prior specimen processing. The drop off in heat capacity appearing above 36 0 K in the C/sub p/ versus T curves of 235 U and 238 U suggest the possibility of: (1) heat evolution from a developing antiphase structure or (2) heat evolution similar to that noted with a quenched martensite. Physical property changes in 238 U at 250 to 270 0 K and at 325 to 350 0 K seem to be related to the heat evolution which starts at 36 0 K during adiabatic heat capacity measurements. The data from heat capacity and thermal conductivity measurements are analyzed to help explain the significance of the sometimes very slight physical property changes observed at 36 to 43, approximately 80, 250 to 270 and 325 to 350 0 K in uranium metal. (U.S.)

  16. Development of a digital astronomical intensity interferometer: laboratory results with thermal light

    Science.gov (United States)

    Matthews, Nolan; Kieda, David; LeBohec, Stephan

    2018-06-01

    We present measurements of the second-order spatial coherence function of thermal light sources using Hanbury-Brown and Twiss interferometry with a digital correlator. We demonstrate that intensity fluctuations between orthogonal polarizations, or at detector separations greater than the spatial coherence length of the source, are uncorrelated but can be used to reduce systematic noise. The work performed here can readily be applied to existing and future Imaging Air-Cherenkov Telescopes used as star light collectors for stellar intensity interferometry to measure spatial properties of astronomical objects.

  17. Mechanical properties of EB-PVD ZrO2 thermal barrier coatings

    International Nuclear Information System (INIS)

    Held, Carolin

    2014-01-01

    In this work, the elastic properties of thermal barrier coatings which were produced by electron-beam enhanced physical vapour deposition were investigated, as well as the dependency of the properties on the sample microstructure, the thermal treatment and the test method. For this purpose, not only commercial coatings were characterized, but also special sample material was used which consists of a 1 mm thick layer of EB-PVD TBC. This material was isothermally heat treated for different times at 950 C, 1100 C and 1200 C and then tested in a specially developed miniaturized bend test and by dynamic mechanical analysis. The sample material was tested by nanoindentation in order to measure the Young's modulus on a local scale, and the porosity of the samples was determined by microstructure analysis and porosimetry. The decrease of porosity could be connected with sintering and subsequent stiffening of the material. The test results are dependent on the tested volume. A small test volume leads to larger measured Young's moduli, while a large test volume yields lower values. The test volume also has an influence on the increase of stiffness during thermal exposure. With a small tested volume, a quicker increase of the Young's modulus was registered, which could be associated to the sintering of local structures.

  18. Final Report: Improving the understanding of the coupled thermal-mechanical-hydrologic behavior of consolidating granular salt

    Energy Technology Data Exchange (ETDEWEB)

    Stormont, John [Univ. of New Mexico, Albuquerque, NM (United States); Lampe, Brandon [Univ. of New Mexico, Albuquerque, NM (United States); Mills, Melissa [Univ. of New Mexico, Albuquerque, NM (United States); Paneru, Laxmi [Univ. of New Mexico, Albuquerque, NM (United States); Lynn, Timothy [Univ. of New Mexico, Albuquerque, NM (United States); Piya, Aayush [Univ. of New Mexico, Albuquerque, NM (United States)

    2017-09-09

    The goal of this project is to improve the understanding of key aspects of the coupled thermal-mechanical-hydrologic response of granular (or crushed) salt used as a seal material for shafts, drifts, and boreholes in mined repositories in salt. The project is organized into three tasks to accomplish this goal: laboratory measurements of granular salt consolidation (Task 1), microstructural observations on consolidated samples (Task 2), and constitutive model development and evaluation (Task 3). Task 1 involves laboratory measurements of salt consolidation along with thermal properties and permeability measurements conducted under a range of temperatures and stresses expected for potential mined repositories in salt. Testing focused on the role of moisture, temperature and stress state on the hydrologic (permeability) and thermal properties of consolidating granular salt at high fractional densities. Task 2 consists of microstructural observations made on samples after they have been consolidated to interpret deformation mechanisms and evaluate the ability of the constitutive model to predict operative mechanisms under different conditions. Task 3 concerns the development of the coupled thermal-mechanical-hydrologic constitutive model for granular salt consolidation. The measurements and observations in Tasks 1 and 2 were used to develop a thermal-mechanical constitutive model. Accomplishments and status from each of these efforts is reported in subsequent sections of this report

  19. A first principles study of the electronic structure, elastic and thermal properties of UB2

    Science.gov (United States)

    Jossou, Ericmoore; Malakkal, Linu; Szpunar, Barbara; Oladimeji, Dotun; Szpunar, Jerzy A.

    2017-07-01

    Uranium diboride (UB2) has been widely deployed for refractory use and is a proposed material for Accident Tolerant Fuel (ATF) due to its high thermal conductivity. However, the applicability of UB2 towards high temperature usage in a nuclear reactor requires the need to investigate the thermomechanical properties, and recent studies have failed in highlighting applicable properties. In this work, we present an in-depth theoretical outlook of the structural and thermophysical properties of UB2, including but not limited to elastic, electronic and thermal transport properties. These calculations were performed within the framework of Density Functional Theory (DFT) + U approach, using Quantum ESPRESSO (QE) code considering the addition of Coulomb correlations on the uranium atom. The phonon spectra and elastic constant analysis show the dynamic and mechanical stability of UB2 structure respectively. The electronic structure of UB2 was investigated using full potential linear augmented plane waves plus local orbitals method (FP-LAPW+lo) as implemented in WIEN2k code. The absence of a band gap in the total and partial density of states confirms the metallic nature while the valence electron density plot reveals the presence of covalent bond between adjacent B-B atoms. We predicted the lattice thermal conductivity (kL) by solving Boltzmann Transport Equation (BTE) using ShengBTE. The second order harmonic and third-order anharmonic interatomic force constants required as input to ShengBTE was calculated using the Density-functional perturbation theory (DFPT). However, we predicted the electronic thermal conductivity (kel) using Wiedemann-Franz law as implemented in Boltztrap code. We also show that the sound velocity along 'a' and 'c' axes exhibit high anisotropy, which accounts for the anisotropic thermal conductivity of UB2.

  20. Optimizing Thermal-Elastic Properties of C/C–SiC Composites Using a Hybrid Approach and PSO Algorithm

    Science.gov (United States)

    Xu, Yingjie; Gao, Tian

    2016-01-01

    Carbon fiber-reinforced multi-layered pyrocarbon–silicon carbide matrix (C/C–SiC) composites are widely used in aerospace structures. The complicated spatial architecture and material heterogeneity of C/C–SiC composites constitute the challenge for tailoring their properties. Thus, discovering the intrinsic relations between the properties and the microstructures and sequentially optimizing the microstructures to obtain composites with the best performances becomes the key for practical applications. The objective of this work is to optimize the thermal-elastic properties of unidirectional C/C–SiC composites by controlling the multi-layered matrix thicknesses. A hybrid approach based on micromechanical modeling and back propagation (BP) neural network is proposed to predict the thermal-elastic properties of composites. Then, a particle swarm optimization (PSO) algorithm is interfaced with this hybrid model to achieve the optimal design for minimizing the coefficient of thermal expansion (CTE) of composites with the constraint of elastic modulus. Numerical examples demonstrate the effectiveness of the proposed hybrid model and optimization method. PMID:28773343

  1. Mechanical and thermal properties of castor oil polyurethane bone cement after gamma irradiation

    International Nuclear Information System (INIS)

    Azevedo, E.C.; Chierice, G.O.; Claro Neto, S.; Lepiesnki, C.M.; Nascimento, E.M.

    2009-01-01

    Polyurethanes from castor oil are being employed as bone cement in medical applications. In this work the thermal and mechanical properties of gamma irradiated polyurethanes derivative from castor oil were investigated by instrumented indentation, thermogravimetry and scanning electron microscopy. A slightly increase in hardness is observed only for doses as high as 100 kGy. Thermal analysis indicates stability at human body temperature. The glass transition temperature has small changes after gamma irradiation. (author)

  2. Effects of nonideal surfaces on the derived thermal properties of Mars

    International Nuclear Information System (INIS)

    Jakosky, B.M.

    1979-01-01

    The thermal inertia of the surface of Mars varies spatially by a factor of 8. This is attributable to changes in the average particle size of the fine material, the surface elevation, the atmospheric opacity due to dust, and the fraction of the surface covered by rocks an fine material. The effects of these nonideal properties on the surface temperatures and derived thermal inertias are modeled, along with the effects of slopes, CO 2 condensed onto the surface, and layering of fine material upon solid rock. The nonideal models are capable of producing thermal behavior similar to that observed by the Viking infrared thermal mapper, including a morning delay in the postdawn temperature rise and an enhanced cooling in the afternoon relative to any ideal, homogeneous model. The enhanced afternoon cooling observed at the Viking 1 landing site is reproduced by the nonideal models while that atop Arsia Mons volcano is not, but may be attributed to the observing geometry. A histogram of surface thermal inertia versus elevation shows at least two distinct classes: a single region near Amazonis Planitia has low inertias at low elevation; many of the remaining data show an anticorrelation between inertia and elevation, expected because of the change in thermal inertia produced by changes in the atmospheric pressure an dust opacity with elevation

  3. Phonon and thermal properties of exfoliated TaSe{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Z.; Jiang, C.; Renteria, J. [Nano-Device Laboratory, Department of Electrical Engineering, Bourns College of Engineering, University of California–Riverside, Riverside, California 92521 (United States); Pope, T. R.; Tsang, C. F.; Stickney, J. L.; Salguero, T. T., E-mail: salguero@uga.edu, E-mail: balandin@ee.ucr.edu [Department of Chemistry, University of Georgia, Athens, Georgia 30602 (United States); Goli, P. [Materials Science and Engineering Program, Bourns College of Engineering, University of California–Riverside, Riverside, California 92521 (United States); Balandin, A. A., E-mail: salguero@uga.edu, E-mail: balandin@ee.ucr.edu [Nano-Device Laboratory, Department of Electrical Engineering, Bourns College of Engineering, University of California–Riverside, Riverside, California 92521 (United States); Materials Science and Engineering Program, Bourns College of Engineering, University of California–Riverside, Riverside, California 92521 (United States)

    2013-11-28

    We report on the phonon and thermal properties of thin films of tantalum diselenide (2H-TaSe{sub 2}) obtained via the “graphene-like” mechanical exfoliation of crystals grown by chemical vapor transport. The ratio of the intensities of the Raman peak from the Si substrate and the E{sub 2g} peak of TaSe{sub 2} presents a convenient metric for quantifying film thickness. The temperature coefficients for two main Raman peaks, A{sub 1g} and E{sub 2g}, are −0.013 and −0.0097 cm{sup −1}/{sup o}C, respectively. The Raman optothermal measurements indicate that the room temperature thermal conductivity in these films decreases from its bulk value of ∼16 W/mK to ∼9 W/mK in 45-nm thick films. The measurement of electrical resistivity of the field-effect devices with TaSe{sub 2} channels shows that heat conduction is dominated by acoustic phonons in these van der Waals films. The scaling of thermal conductivity with the film thickness suggests that the phonon scattering from the film boundaries is substantial despite the sharp interfaces of the mechanically cleaved samples. These results are important for understanding the thermal properties of thin films exfoliated from TaSe{sub 2} and other metal dichalcogenides, as well as for evaluating self-heating effects in devices made from such materials.

  4. Thermal Stability and Magnetic Properties of Polyvinylidene Fluoride/Magnetite Nanocomposites

    OpenAIRE

    Ouyang, Zen-Wei; Chen, Erh-Chiang; Wu, Tzong-Ming

    2015-01-01

    This work describes the thermal stability and magnetic properties of polyvinylidene fluoride (PVDF)/magnetite nanocomposites fabricated using the solution mixing technique. The image of transmission electron microscopy for PVDF/magnetite nanocomposites reveals that the 13 nm magnetite nanoparticles are well distributed in PVDF matrix. The electroactive β-phase and piezoelectric responses of PVDF/magnetite nanocomposites are increased as the loading of magnetite nanoparticles increases. The pi...

  5. Estimation of the thermal properties in alloys as an inverse problem

    International Nuclear Information System (INIS)

    Zueco, J.; Alhama, F.

    2005-01-01

    This paper provides an efficient numerical method for estimating the thermal conductivity and heat capacity of alloys, as a function of the temperature, starting from temperature measurements (including errors) in heating and cooling processes. The proposed procedure is a modification of the known function estimation technique, typical of the inverse problem field, in conjunction with the network simulation method (already checked in many non-lineal problems) as the numerical tool. Estimations only require a point of measurement. The methodology is applied for determining these thermal properties in alloys within ranges of temperature where allotropic changes take place. These changes are characterized by sharp temperature dependencies. (Author) 13 refs

  6. Thermal energy storage material thermophysical property measurement and heat transfer impact

    Science.gov (United States)

    Tye, R. P.; Bourne, J. G.; Destarlais, A. O.

    1976-01-01

    The thermophysical properties of salts having potential for thermal energy storage to provide peaking energy in conventional electric utility power plants were investigated. The power plants studied were the pressurized water reactor, boiling water reactor, supercritical steam reactor, and high temperature gas reactor. The salts considered were LiNO3, 63LiOH/37 LiCl eutectic, LiOH, and Na2B4O7. The thermal conductivity, specific heat (including latent heat of fusion), and density of each salt were measured for a temperature range of at least + or - 100 K of the measured melting point. Measurements were made with both reagent and commercial grades of each salt.

  7. Evaluation of thermal properties of food materials at high pressures using a dual-needle line-heat-source method.

    Science.gov (United States)

    Zhu, S; Ramaswamy, H S; Marcotte, M; Chen, C; Shao, Y; Le Bail, A

    2007-03-01

    Thermal properties of food systems at high pressure (HP) are important in the design and operation of HP processing equipment. Available techniques for thermal property evaluation under HP conditions are still very limited. In this study, a dual-needle line-heat-source (DNL) device was installed in an HP vessel to evaluate thermal conductivity (k), diffusivity (alpha), and volumetric heat capacity (C(pV)) of foods at high pressure. The DNL probe was calibrated using glycerin (0.1 MPa) and 2% (w/w) agar gel (0.1 to 350 MPa) at 5 and 25 degrees C. Calibration results showed a good correlation with the reference data of pure water: R(2)= 0.966 for thermal conductivity and R(2)= 0.837 for diffusivity, and a small standard deviation of relative error (3.18%) for the volumetric heat capacity. Fresh potato and cheddar cheese were used as test samples at 5 degrees C at selected pressure levels (0.1 to 350 MPa). The potato samples gave thermal properties very close to those of pure water, but much higher than those of the cheese. The k and alpha values of both potato and cheese increased with pressure and a 2nd-order polynomial well fitted their pressure dependency. The volumetric heat capacity data did not show a clear pressure-dependency trend. The experimental system worked well for the evaluation of thermal properties at pressures up to 350 MPa.

  8. Nanoclay Effect on the Flow and Thermal Properties of PP/SEBS-g-MA Blend

    Directory of Open Access Journals (Sweden)

    M. Ranjbar

    2014-01-01

    Full Text Available The effect of nanoclay (Cloisite® 15A was studied in relation to the flow behavior, mechanical and thermal properties of polypropylene/maleic anhydride-g-(styrene-ethylene-butylene-styrene triblock copolymer (PP/SEBS(15%-g-MA blend. In this regard, the composites based on the blend and various amounts of nanoclay (1,3,5 wt% were melt compounded using an internal mixer at the temperature of 190°C, rotor speed of 75rpm for 12min. The prepared samples were compression molded in a hot-press machine under the conditions of 190°C, 31 MPa pressure for 9 min to obtain the sheets in various thicknesses. The sheets were then cooled to ambient temperature with cooling water at the rate of 1.5°C.s-1. X-ray diffraction (XRD and transmission electron microscopy (TEM were used to study the structure and morphology of the samples. In addition, the mechanical and thermal properties were determined by standard methods. The results of X-ray diffraction and transmission electron photographs confirmed both exfoliated and intercalated structures in the prepared samples. There were balanced strength/toughness properties in all the prepared nanocomposites by addition of both SEBS-g-MA and clay simultaneously. The measurement of rheological properties showed that as the shear rate increased, the apparent viscosity of the samples decreased (shear thinning behavior. Gradual increase in incorporation of nanoclay also decreased the melt flow index (MFI values. In addition, increases in nanoclay content had an insignificant effect on the thermal behavior and in that respect there were slight increases in degree of crystallinity, heat deflection temperature (HDT as well as Vicat softening point by slight increase in temperatureThe effect of nanoclay (Cloisite® 15A was studied in relation to the flow behavior, mechanical and thermal properties of polypropylene/maleic anhydride-g-(styrene-ethylene-butylene-styrene triblock copolymer (PP/SEBS(15%-g-MA blend. In this regard

  9. Optical and thermal properties in ultrafast laser surface nanostructuring on biodegradable polymer

    Science.gov (United States)

    Yada, Shuhei; Terakawa, Mitsuhiro

    2015-03-01

    We investigate the effect of optical and thermal properties in laser-induced periodic surface structures (LIPSS) formation on a poly-L-lactic acid (PLLA), a biodegradable polymer. Surface properties of biomaterials are known to be one of the key factors in tissue engineering. Methods to process biomaterial surfaces have been studied widely to enhance cell adhesive and anisotropic properties. LIPSS formation has advantages in a dry processing which is able to process complex-shaped surfaces without using a toxic chemical component. LIPSS, however, was difficult to be formed on PLLA due to its thermal and optical properties compared to other polymers. To obtain new perspectives in effect of these properties above, LIPSS formation dependences on wavelength, pulse duration and repetition rate have been studied. At 800 nm of incident wavelength, high-spatial frequency LIPSS (HSFL) was formed after applying 10000 femtosecond pulses at 1.0 J/cm2 in laser fluence. At 400 nm of the wavelength, HSFL was formed at fluences higher than 0.20 J/cm2 with more than 3000 pulses. Since LIPSS was less formed with lower repetition rate, certain heat accumulation may be required for LIPSS formation. With the pulse duration of 2.0 ps, higher laser fluence as well as number of pulses compared to the case of 120 fs was necessary. This indicates that multiphoton absorption process is essential for LIPSS formation. Study on biodegradation modification was also performed.

  10. Influence of the reaction stoichiometry on the mechanical and thermal properties of SWCNT-modified epoxy composites

    International Nuclear Information System (INIS)

    Ashrafi, Behnam; Johnston, Andrew; Martinez-Rubi, Yadienka; Kingston, Christopher T; Simard, Benoit; Khoun, Lolei; Yourdkhani, Mostafa; Hubert, Pascal

    2013-01-01

    Previous studies suggest that carbon nanotubes (CNTs) have a considerable influence on the curing behavior and crosslink density of epoxy resins. This invariably has an important effect on different thermal and mechanical properties of the epoxy network. This work focuses on the important role of the epoxy/hardener mixing ratio on the mechanical and thermal properties of a high temperature aerospace-grade epoxy (MY0510 Araldite as an epoxy and 4,4′-diaminodiphenylsulfone as an aromatic hardener) modified with single-walled carbon nanotubes (SWCNTs). The effects of three different stoichiometries (stoichiometric and off-stoichiometric) on various mechanical and thermal properties (fracture toughness, tensile properties, glass transition temperature) of the epoxy resin and its SWCNT-modified composites were obtained. The results were also supported by Raman spectroscopy and scanning electron microscopy (SEM). For the neat resin, it was found that an epoxy/hardener molar ratio of 1:0.8 provides the best overall properties. In contrast, the pattern in property changes with the reaction stoichiometry was considerably different for composites reinforced with unfunctionalized SWCNTs and reduced SWCNTs. A comparison among composites suggests that a 1:1 molar ratio considerably outperforms the other two ratios examined in this work (1:0.8 and 1:1.1). This composition at 0.2 wt% SWCNT loading provides the highest overall mechanical properties by improving fracture toughness, ultimate tensile strength and ultimate tensile strain of the epoxy resin by 40%, 34%, 54%, respectively. (paper)

  11. Structure impact on the thermal and electronic properties of bismuth telluride by ab-initio and molecular dynamics calculations

    International Nuclear Information System (INIS)

    Termentzidis, K; Pokropivny, A; Xiong, S-Y; Chumakov, Y; Volz, S; Woda, M; Cortona, P

    2012-01-01

    We use molecular dynamics and ab-initio methods to predict the thermal and electronic properties of new materials with high figures of merit. The simulated systems are bulk bismuth tellurides with antisite and vacancy defects. Optimizations of the materials under investigation are performed by the SIESTA code for subsequent calculations of force constants, electronic properties, and Seebeck coefficients. The prediction of the thermal conductivity is made by Non-Equilibrium Molecular Dynamics (NEMD) using the LAMMPS code. The thermal conductivity of bulk bismuth telluride with different stoichiometry and with a number of substitution defects is calculated. We have found that the thermal conductivity can be decreased by 60% by introducing vacancy defects. The calculated thermal conductivities for the different structures are compared with the available experimental and theoretical results.

  12. Development of the fabrication of ultra-low density ploy (4-methyl-1-pentene) (PMP) foams by thermal induced phase-inversion technique

    International Nuclear Information System (INIS)

    Zhang Lin; Wang Chaoyang; Luo Xuan; Du Kai; Tu Haiyan; Fan Hong; Luo Qing; Yuan Guanghui; Huang Lizhen

    2003-01-01

    By thermally induced phase-inversion technique, ploy (4-methyl-1-pentene) (PMP) foams are successfully prepared; the density and pore size are 3-80 mg/cm 3 and 1-20 μm respectively. Durene/naphthalene (60/40) is confirmed as the suitable solvent/nonsolvent binary system. The PMP's thermal properties are characterized by TG-DSC system. It is found that the foams thermal properties depend on the density. The thermal analysis method is utilized to measure the gelation of PMP in the binary solvent/nonsolvent system. The range of gelation temperature is preliminarily determined. The influence of mixture system composition and the cooling rate during the making of foams is discussed. TG-DSC is applied to determine the thermal properties of low-density PMP foams prepared in the laboratory. And the effect of density change on the thermal stability of foams are studied. The thermal analysis data play a great role in improving the foam quality. (authors)

  13. Thermal properties of andesite from Popocatepetl and Volcán de Colima, México.

    Science.gov (United States)

    Cardenas-Sanchez, Enrique; De la Cruz-Reina, Servando; Varley, Nick

    2015-04-01

    The thermal conductivity (K), specific heat (Cp) and the coefficient of heat transfer surface (H) are the basic parameters to describe the process of cooling a volcanic rock fragment released in an explosive event. The analysis of the cooling process by conduction, convection and radiation of heat in volcanic rock fragments, has been limited to basalts, and various minerals such as olivine, pyroxene, quartz, etc. (Miao & Chen, 2014; Branlund & Hofmeister, 2012; Romine et al, 2012;. Schön, 2011; Stroberg et al, 2010;. Schatz & Simmons, 1972). There are no detailed studies on the thermal properties of the andesites, abundant in continental stratovolcanoes, and particularly susceptible from lava domes with frequent destruction processes, such as Popocatepetl and Volcan de Colima. Previously, we developed an algorithm for calculation of the grain-size distribution, degree of fragmentation, the thermal energy released and its possible correlation with Volcanic Explosive Index (VEI) from the cooling curves of fragments from vulcanian and strombolian explosions. These curves were obtained from sequences of time over incandescent deposits recorded at selected pixel thermal images of vulcanian activity in the Popocatepetl and Volcan de Colima, Mexico. However, the model was limited by the lack of thermal parameters of the andesites, forcing a first approximation using basalts data. We present a simple model for the cooling process using andesites samples from Popocatépetl and Volcan de Colima. First, the samples were subjected to a rounding process to minimize surface effects. Then, heated to 800 ° C were extracted from the muffle and cooling rate is measured. The thermal conductivity and coefficient of surface heat are determined using a thermal camera and three thermocouples embedded at various depths within the sample. An inversion method was implemented to determine the thermal properties parameters , by comparing the observed data regarding cooling model for a solid

  14. Thermophysical parameters from laboratory measurements and tests in borehole heat exchangers

    Science.gov (United States)

    Pacetti, Chiara; Giuli, Gabriele; Invernizzi, Chiara; Chiozzi, Paolo; Verdoya, Massimo

    2017-04-01

    Besides the type of thermal regime, the performance of borehole heat exchangers relies on the overall thermal resistance of the borehole. This parameter strongly depends on the underground thermal conductivity, which accounts for most of the heat that can be extracted. The geometric configuration and the increase of thermal conductivity of the grout filling back the bore can yield a non-negligible enhancement in thermal performances. In this paper, we present a study on a pilot geothermal plant consisting of two borehole heat exchangers, 95 m deep and 9 m apart. Laboratory and in situ tests were carried out with the aim of investigating underground thermal properties, mechanisms of heat transfer and thermal characteristics of the filling grouts. Samples of grouting materials were analysed in the lab for assessing the thermal conductivity. An attempt to improve the thermal conductivity was made by doping grouts with alumina. Results showed that alumina large concentrations can increase the thermal conductivity by 25-30%. The in situ experiments included thermal logs under conditions of thermal equilibrium and thermal response tests (TRTs). The analysis of the temperature-depth profiles, based on the mass and energy balance in