The Experts below are selected from a list of 102102 Experts worldwide ranked by ideXlab platform
D. Buddhi - One of the best experts on this subject based on the ideXlab platform.
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Thermal Cycle testing of calcium chloride hexahydrate as a possible pcm for latent heat storage
Solar Energy Materials and Solar Cells, 2008Co-Authors: V V Tyagi, D. BuddhiAbstract:In order to study the changes in latent heat of fusion and melting temperature of calcium chloride hexahydrate (CaCl2·6H2O) inorganic salt as a latent heat storage material, a thousand accelerated Thermal Cycle tests have been conducted. The effect of Thermal cycling and the reliability in terms of the changing of the melting temperature using a differential scanning calorimeter (DSC) is determined. It has been noticed that the CaCl2·6H2O melts between a stable range of temperature and has shown small variations in the latent heat of fusion during the Thermal cycling process. Thus, it can be a promising phase change material (PCM) for heating and cooling applications for various building/storage systems.
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accelerated Thermal Cycle test of acetamide stearic acid and paraffin wax for solar Thermal latent heat storage applications
Energy Conversion and Management, 2002Co-Authors: Atul Sharma, S D Sharma, D. BuddhiAbstract:1500 accelerated Thermal Cycle tests have been conducted to study the changes in latent heat of fusion and melting temperature of commercial grade acetamide, stearic acid and paraffin wax. It has been noticed that the stearic acid melts over a wide range of temperature, has shown two melting points and has large variations in latent heat of fusion. Paraffin wax and acetamide have shown reasonably good Thermal stability for melting temperature and variations in latent heat of fusion during the cycling process.
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Thermal Cycle test of urea for latent heat storage applications
International Journal of Energy Research, 2001Co-Authors: Atul Sharma, D. Buddhi, S D Sharma, R. L. SawhneyAbstract:Accelerated Thermal Cycle tests for melt/freeze Cycles of urea were conducted. Urea has shown a very high degradation in its latent heat and melting point within the first few Cycles and did not melt after a few Cycles. It is recommended that urea should not be used as a latent heat storage material. Copyright © 2001 John Wiley & Sons, Ltd.
Jeffry W Stevenson - One of the best experts on this subject based on the ideXlab platform.
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Compliant alkali silicate sealing glass for solid oxide fuel cell applications: Thermal Cycle stability and chemical compatibility
Journal of Power Sources, 2011Co-Authors: Yeongshyung Chou, Jeffry W Stevenson, Jung-pyung Choi, Edwin C. Thomsen, Riley T. Williams, Nathan L. Canfield, Jeff F. Bonnett, Amit Shyam, Edgar Lara-curzioAbstract:Abstract An alkali silicate glass (SCN-1) is currently being evaluated as a candidate sealing glass for solid oxide fuel cell (SOFC) applications. The glass containing ∼17 mole% alkalis (K 2 O and Na 2 O) remains vitreous and compliant during SOFC operation, unlike conventional SOFC sealing glasses, which experience substantial devitrification after the sealing process. The non-crystallizing compliant sealing glass has lower glass transition and softening temperatures since the microstructure remains glassy without significant crystallite formation, and hence can relieve or reduce residual stresses and also has the potential for crack healing. Sealing approaches based on compliant glass will also need to satisfy all the mechanical, Thermal, chemical, physical, and electrical requirements for SOFC applications, not only in bulk properties but also at sealing interfaces. In this first of a series of papers we will report the Thermal Cycle stability of the glass when sealed between two SOFC components, i.e., a NiO/YSZ anode supported YSZ bilayer and a coated ferritic stainless steel interconnect material. High temperature leak rates were monitored versus Thermal Cycles between 700 and 850 °C using back pressures ranging from 1.4 to 6.8 kPa (0.2–1.0 psi). IsoThermal stability was also evaluated in a dual environment consisting of flowing dilute H 2 fuel versus ambient air. In addition, chemical compatibility at the alumina and YSZ interfaces was examined with scanning electron microscopy and energy dispersive spectroscopy. The results shed new light on the topic of SOFC glass seal development.
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Thermal Cycle stability of a novel glass mica composite seal for solid oxide fuel cells effect of glass volume fraction and stresses
Journal of Power Sources, 2005Co-Authors: Yeongshyung Chou, Jeffry W Stevenson, Prabhakar SinghAbstract:Abstract A novel glass–mica composite seal was developed based on a previously reported concept of “infiltrated” mica seals for solid oxide fuel cells. Ba–Al–Ca silicate sealing glass powder and Phlogopite mica flakes were mixed at glass volume fractions of 10–50 vol.% to make the glass–mica composite seals. The seals were leak tested for short-term Thermal Cycle stability as a function of glass volume fraction. Composite seals with 10 and 20 vol.% glass were also leak tested under compressive stresses from 3 to 100 psi and helium pressures of 0.2 or 2 psi. Post-mortem microstructure analyses were used to characterize the fracture (leak path) of the glass–mica composite seals and were related to the high temperature leakages. Open circuit voltage tests on dense 8YSZ electrolyte with the glass–mica composite seal showed very good Thermal Cycle stability over 250 Cycles with minute (
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infiltrated phlogopite micas with superior Thermal Cycle stability as compressive seals for solid oxide fuel cells
2005Co-Authors: Yeongshyung Chou, Jeffry W StevensonAbstract:Thermal Cycle stability is one of the most stringent requirements for sealants in solid oxide fuel cell stacks. The sealants have to survive several hundreds to thousands of Thermal Cycles during lifetime operation in stationary and transportation applications. Recently, researchers at the Pacific Northwest National Laboratory have developed a novel method to infiltrate the mica flakes with a wetting or liquid forming material such that the leak path will be reduced from 3-D to 2-D and achieve good Thermal Cycle stability with low leak rates.
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long term Thermal cycling of phlogopite mica based compressive seals for solid oxide fuel cells
Journal of Power Sources, 2005Co-Authors: Yeongshyung Chou, Jeffry W StevensonAbstract:Abstract Planar solid oxide fuel cells (SOFCs) require sealants to function properly in harsh environments at elevated temperatures. The SOFC stacks are expected to experience multiple Thermal Cycles (perhaps thousands of Cycles for some applications) during their lifetime service in stationary or transportation applications. As a result, Thermal Cycle stability is considered a top priority for SOFC sealant development. In previous work, we have developed a hybrid mica-based compressive seal with very low leak rates of 2–4 × 10 −2 to 10 −3 sccm cm −1 at 800 °C, and showed stable leak rates over limited Thermal Cycles. In this paper we present results of long-term Thermal Cycle testing (>1000 Thermal Cycles) of Phlogopite mica-based compressive seals. Open-circuit voltage (OCV) was measured on a 2 in. × 2 in. 8-YSZ plate with the hybrid Phlogopite mica seals during Thermal cycling in a dual environment (2.75% H 2 /Ar versus air). During two long-term cycling tests, the measured OCVs were found to be consistent with the calculated Nernst voltages. The hybrid mica seal showed excellent Thermal Cycle stability over 1000 Thermal Cycles and can be considered a strong candidate for SOFC applications.
Yeongshyung Chou - One of the best experts on this subject based on the ideXlab platform.
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Compliant alkali silicate sealing glass for solid oxide fuel cell applications: Thermal Cycle stability and chemical compatibility
Journal of Power Sources, 2011Co-Authors: Yeongshyung Chou, Jeffry W Stevenson, Jung-pyung Choi, Edwin C. Thomsen, Riley T. Williams, Nathan L. Canfield, Jeff F. Bonnett, Amit Shyam, Edgar Lara-curzioAbstract:Abstract An alkali silicate glass (SCN-1) is currently being evaluated as a candidate sealing glass for solid oxide fuel cell (SOFC) applications. The glass containing ∼17 mole% alkalis (K 2 O and Na 2 O) remains vitreous and compliant during SOFC operation, unlike conventional SOFC sealing glasses, which experience substantial devitrification after the sealing process. The non-crystallizing compliant sealing glass has lower glass transition and softening temperatures since the microstructure remains glassy without significant crystallite formation, and hence can relieve or reduce residual stresses and also has the potential for crack healing. Sealing approaches based on compliant glass will also need to satisfy all the mechanical, Thermal, chemical, physical, and electrical requirements for SOFC applications, not only in bulk properties but also at sealing interfaces. In this first of a series of papers we will report the Thermal Cycle stability of the glass when sealed between two SOFC components, i.e., a NiO/YSZ anode supported YSZ bilayer and a coated ferritic stainless steel interconnect material. High temperature leak rates were monitored versus Thermal Cycles between 700 and 850 °C using back pressures ranging from 1.4 to 6.8 kPa (0.2–1.0 psi). IsoThermal stability was also evaluated in a dual environment consisting of flowing dilute H 2 fuel versus ambient air. In addition, chemical compatibility at the alumina and YSZ interfaces was examined with scanning electron microscopy and energy dispersive spectroscopy. The results shed new light on the topic of SOFC glass seal development.
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Thermal Cycle stability of a novel glass mica composite seal for solid oxide fuel cells effect of glass volume fraction and stresses
Journal of Power Sources, 2005Co-Authors: Yeongshyung Chou, Jeffry W Stevenson, Prabhakar SinghAbstract:Abstract A novel glass–mica composite seal was developed based on a previously reported concept of “infiltrated” mica seals for solid oxide fuel cells. Ba–Al–Ca silicate sealing glass powder and Phlogopite mica flakes were mixed at glass volume fractions of 10–50 vol.% to make the glass–mica composite seals. The seals were leak tested for short-term Thermal Cycle stability as a function of glass volume fraction. Composite seals with 10 and 20 vol.% glass were also leak tested under compressive stresses from 3 to 100 psi and helium pressures of 0.2 or 2 psi. Post-mortem microstructure analyses were used to characterize the fracture (leak path) of the glass–mica composite seals and were related to the high temperature leakages. Open circuit voltage tests on dense 8YSZ electrolyte with the glass–mica composite seal showed very good Thermal Cycle stability over 250 Cycles with minute (
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infiltrated phlogopite micas with superior Thermal Cycle stability as compressive seals for solid oxide fuel cells
2005Co-Authors: Yeongshyung Chou, Jeffry W StevensonAbstract:Thermal Cycle stability is one of the most stringent requirements for sealants in solid oxide fuel cell stacks. The sealants have to survive several hundreds to thousands of Thermal Cycles during lifetime operation in stationary and transportation applications. Recently, researchers at the Pacific Northwest National Laboratory have developed a novel method to infiltrate the mica flakes with a wetting or liquid forming material such that the leak path will be reduced from 3-D to 2-D and achieve good Thermal Cycle stability with low leak rates.
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long term Thermal cycling of phlogopite mica based compressive seals for solid oxide fuel cells
Journal of Power Sources, 2005Co-Authors: Yeongshyung Chou, Jeffry W StevensonAbstract:Abstract Planar solid oxide fuel cells (SOFCs) require sealants to function properly in harsh environments at elevated temperatures. The SOFC stacks are expected to experience multiple Thermal Cycles (perhaps thousands of Cycles for some applications) during their lifetime service in stationary or transportation applications. As a result, Thermal Cycle stability is considered a top priority for SOFC sealant development. In previous work, we have developed a hybrid mica-based compressive seal with very low leak rates of 2–4 × 10 −2 to 10 −3 sccm cm −1 at 800 °C, and showed stable leak rates over limited Thermal Cycles. In this paper we present results of long-term Thermal Cycle testing (>1000 Thermal Cycles) of Phlogopite mica-based compressive seals. Open-circuit voltage (OCV) was measured on a 2 in. × 2 in. 8-YSZ plate with the hybrid Phlogopite mica seals during Thermal cycling in a dual environment (2.75% H 2 /Ar versus air). During two long-term cycling tests, the measured OCVs were found to be consistent with the calculated Nernst voltages. The hybrid mica seal showed excellent Thermal Cycle stability over 1000 Thermal Cycles and can be considered a strong candidate for SOFC applications.
Atul Sharma - One of the best experts on this subject based on the ideXlab platform.
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Thermal Cycle test of binary mixtures of some fatty acids as phase change materials for building applications
Energy and Buildings, 2015Co-Authors: Atul Sharma, A ShuklaAbstract:Abstract This paper deals with the Thermal Cycle tests of the binary mixtures based on fatty acids, i.e. capric acid (CA), lauric acid (LA), myristic acid (MA), palmitic acid (PA) and stearic acid (SA). Overall, 13 binary mixtures, i.e. CA–LA (40/60 wt.%, 50/50 wt.%, 60/40 wt.%, 70/30 wt.% and 80/20 wt.%), CA–MA (70/30 wt.%, 80/20 wt.% and 90/10 wt.%), CA–PA (70/30 wt.%, 80/20 wt.% and 90/10 wt.%) and CA–SA (60/40 wt.% and 90/10 wt.%) were developed as latent heat energy storage materials for the building applications. The Differential Scanning Calorimetry (DSC) technique was applied to the binary mixtures after 0, 50, 100, 150, 200, 250, 300, 600, 900, 1200 melt/freeze Cycles to measure the melting temperatures and the latent heats of fusion. The DSC results showed that the changes in melting temperature were in between −1.69 °C to 4.33 °C, and the changes in the latent heat fusion was −35% to +25%. These results show that the melting temperatures and latent heat values of the PCMs are in the range of about 21–30 °C and 100–170 J/g which showed that these materials have good Thermal stability up to 1200 Thermal Cycles and can be potentially applied for building applications.
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accelerated Thermal Cycle test of acetamide stearic acid and paraffin wax for solar Thermal latent heat storage applications
Energy Conversion and Management, 2002Co-Authors: Atul Sharma, S D Sharma, D. BuddhiAbstract:1500 accelerated Thermal Cycle tests have been conducted to study the changes in latent heat of fusion and melting temperature of commercial grade acetamide, stearic acid and paraffin wax. It has been noticed that the stearic acid melts over a wide range of temperature, has shown two melting points and has large variations in latent heat of fusion. Paraffin wax and acetamide have shown reasonably good Thermal stability for melting temperature and variations in latent heat of fusion during the cycling process.
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Thermal Cycle test of urea for latent heat storage applications
International Journal of Energy Research, 2001Co-Authors: Atul Sharma, D. Buddhi, S D Sharma, R. L. SawhneyAbstract:Accelerated Thermal Cycle tests for melt/freeze Cycles of urea were conducted. Urea has shown a very high degradation in its latent heat and melting point within the first few Cycles and did not melt after a few Cycles. It is recommended that urea should not be used as a latent heat storage material. Copyright © 2001 John Wiley & Sons, Ltd.
R D K Misra - One of the best experts on this subject based on the ideXlab platform.
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high toughness in the intercritically reheated coarse grained icrcg heat affected zone haz of low carbon microalloyed steel
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2014Co-Authors: Jianjun Wang, Hui Xie, Cairu Gao, R D K MisraAbstract:Abstract Motivated by the small lattice mismatch between ferrite and vanadium nitride (VN), we describe here the welding Thermal Cycle simulation that provides high toughness in the ICRCG HAZ of low carbon V–N steel. This unique behavior is attributed to the formation of ultra-fine grained ferrite along prior austenite grain boundaries generated by the first pass welding Thermal Cycle with high misorientation boundaries, where V(C, N) precipitates provide potential nucleation sites for ferrite, leading to extraordinary refinement of martensite/austenite (M/A) constituent. Nitrogen stimulates the precipitation behavior of V(C, N). The nucleation of high density of V(C, N) precipitates consumes carbon-content in the austenite, leading to decrease in the carbon-content in the M/A constituent, with consequent decrease in hardness. The increase in toughness is explained in terms of Griffith's crack propagation theory.
