scholarly journals Investigation of Thermophysical Properties of Three Barrel Steels

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 573 ◽  
Author(s):  
Piotr Koniorczyk ◽  
Janusz Zmywaczyk ◽  
Andrzej Dębski ◽  
Mateusz Zieliński ◽  
Marek Preiskorn ◽  
...  
Keyword(s):  
Phase Transition ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Room Temperature ◽  
Light Flash ◽  
Austenite Phase ◽  
Inconel 600 ◽  
Duplex Steel ◽  
Heat Capacity Measurements ◽  
Specialized Measuring

In this paper, thermal diffusivity and heat capacity measurements were performed for three types of barrel steel, 38HMJ (1.8509), 30HN2MFA, and duplex (1.4462). Thermal diffusivity tests as a function of temperature were performed in the range of room temperature (RT) to 500 °C, and specific heat in the range of RT to 1000 °C. All tests were carried out using NETZSCH specialized measuring stands: LFA 467 light flash apparatus and DSC 404 F1 Pegasus differential scanning calorimeter. In the measurements of thermal diffusivity, the reference material Inconel 600 was used. This made it possible to determine thermal conductivity and specific heat as a function of the temperature of barrel steel. The results of specific heat tests of the 38HMJ and the 30HN2MFA steels show a ferrite–austenite phase transition in the 750–810 °C temperature range. This transition was not observed in the duplex steel.

Thermal Diffusivity and Phase Transition of Rare Earth Manganites

2006 ◽  
Vol 321-323 ◽  
pp. 1695-1698 ◽  
Author(s):  
Migaku Kobayashi ◽  
Hirohisa Sato ◽  
Yoshihiko Hiyoshi ◽  
Naoki Kamegashira ◽  
Doh Jae Lee ◽  
...  
Keyword(s):  
Phase Transition ◽  
Thermal Analysis ◽  
Transition Temperature ◽  
Thermal Diffusivity ◽  
Room Temperature ◽  
Laser Flash ◽  
Oxygen Nonstoichiometry ◽  
Flash Method ◽  
X Ray ◽  
Increasing Temperature

Thermal diffusivity of nonstoichiometric PrMnO3 and NdMnO3 phases were measured by laser flash method from room temperature to 1100 K, in addition to the data of electrical conductivity, thermal analysis and high temperature X-ray diffractometry to detect the phase transition. The thermal diffusivity curve varied with increasing temperature and showed a clear anomaly with a sudden dip at the phase transition temperature. The transition temperature decreases with oxygen nonstoichiometry in each phase.

Thermophysical Properties of Germanium for Thermal Analysis of Growth from the Melt

1981 ◽  
Vol 9 ◽  
Author(s):  
Roger K. Crouch ◽  
A. L. Fripp ◽  
W. J. Debnam ◽  
R. E. Taylor ◽  
H. Groot
Keyword(s):  
Thermal Conductivity ◽  
Thermal Analysis ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Thermophysical Properties ◽  
Room Temperature ◽  
Bridgman Method ◽  
The Other ◽  
Temperature Range ◽  
Diffusivity Measurements

ABSTRACTThe thermal diffusivity of Ge has been measured over a temperature range from 300° C to 1010° C which includes values for the melt. Specific heat has been measured from room temperature to 727° C. Thermal conductivity has been calculated over the same temperature range as the diffusivity measurements. These data are reported along with the best values from the literature for the other parameters which are required to calculate the temperature and convective fields for the growth of germanium by the Bridgman method. These parameters include the specific heat, the viscosity, the emissivity, and the density as a function of temperature.

Room-temperature phase transition in Rb2CoCl4. heat capacity measurements

1986 ◽  
Vol 95 (2) ◽  
pp. K101-K103 ◽  
Author(s):  
P. Vaněk ◽  
B. Březina ◽  
M. Havránková ◽  
J. Biroš
Keyword(s):  
Phase Transition ◽  
Heat Capacity ◽  
Room Temperature ◽  
Temperature Phase ◽  
Temperature Phase Transition ◽  
Heat Capacity Measurements

Phase Behavior of La1-xMnO3-1.5x with Trivalent Manganese Ion

2004 ◽  
Vol 449-452 ◽  
pp. 741-744 ◽  
Author(s):  
M. Kobayashi ◽  
Hirohisa Sato ◽  
Naoki Kamegashira
Keyword(s):  
Phase Transition ◽  
Thermal Analysis ◽  
Electrical Conductivity ◽  
High Temperature ◽  
Thermal Diffusivity ◽  
Room Temperature ◽  
Orthorhombic Phase ◽  
Ceramic Method ◽  
X Ray ◽  
Manganese Ion

Defect perovskite, La1-xMnO3-1.5x (x=0.00-0.10), was synthesized by conventional ceramic method and phase transition was measured by X-ray diffractometry, electrical conductivity, thermal diffusivity and thermal analysis. La1-xMnO3-1.5x (x=0.00-0.09) have single orthorhombic phase corresponding to GdFeO3 type perovskite structure at room temperature, while have rhombohedral structural at high temperature. The transition temperatures observed from electric conductivity, DSC, thermal diffusivity were mostly in agreement and they slightly decrease with increasing x.

Thermal conductivity and thermal diffusivity of selected oxide single crystals

2001 ◽  
Vol 16 (3) ◽  
pp. 678-682 ◽  
Author(s):  
A. Stanimirovic ◽  
N. M. Balzaretti ◽  
A. Feldman ◽  
J. E. Graebner
Keyword(s):  
Thermal Conductivity ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Single Crystals ◽  
Room Temperature ◽  
Structural Orientation ◽  
Relative Standard ◽  
Orthogonal Orientation

Values for the thermal conductivity κ and the thermal diffusivity D of four oxide single crystals were obtained. Near room temperature, the values for κ (W cm−1 K−1) and D (cm2 s−1) are as follows: LaAlO3, κ = 0.115, D = 0.0446; NdGaO3, κ = 0.068, D = 0.0197 for one structural orientation, and κ = 0.059, D = 0.0195 for an orthogonal orientation; (LaAlO3)0.3–SrAl0.5Ta0.5O3, κ = 0.051, D = 0.0133; and, ScAlMgO4, κ = 0.062, D = 0.0229. The relative standard uncertainties in these values are ±10% (1 σ). These values allowed us to calculate the specific heat of the materials. The thermal conductivity was measured by a dc heated bar method, and the thermal diffusivity was measured by a modification of Ångström's method.

scholarly journals Temperature-dependent thermal properties of spark plasma sintered alumina

2017 ◽  
Vol 49 (2) ◽  
pp. 117-128 ◽  
Author(s):  
Nouari Saheb ◽  
Umer Hayat
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Room Temperature ◽  
Alumina Powder ◽  
Temperature Dependent ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Sintering Method

In this work, we report temperature-dependent thermal properties of alumina powder and bulk alumina consolidated by spark plasma sintering method. The properties were measured between room temperature and 250?C using a thermal constants analyzer. Alumina powder had very low thermal properties due to the presence of large pores and absence of bonding between its particles. Fully dense alumina with a relative density of 99.6 % was obtained at a sintering temperature of 1400?C and a holding time of 10 min. Thermal properties were found to mainly dependent on density. Thermal conductivity, thermal diffusivity, and specific heat of the fully dense alumina were 34.44 W/mK, 7.62 mm2s-1, and 1.22 J/gK, respectively, at room temperature. Thermal conductivity and thermal diffusivity decreased while specific heat increased with the increase in temperature from room temperature to 250?C.

Effect of Mechanical Compression on Thermal Characteristics of Tissue-Mimicking Material

2015 ◽  
Author(s):  
Binh T. Hoang ◽  
Austin Roth ◽  
Adriana Druma ◽  
Mallika Keralapura ◽  
Sang-Joon John Lee
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Flux ◽  
Heat Capacity ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Room Temperature ◽  
Mechanical Compression ◽  
Tissue Mimicking Material

Tissue-mimicking materials (TMM) are often used as surrogates for human tissue when developing prospective treatments such as thermal ablation of tumors. Localized heating or ablation may be applied by methods including high-intensity focused ultrasound (HIFU), radio frequency (RF), microwave, and laser treatment. In such methods, confining the heated region to a narrow target is an important concern for minimizing collateral damage to surrounding healthy tissue. Mechanical compression can potentially assist in confining heat near a target region by constricting microvascular blood flow. However, characterization of the effects of compression on thermal properties of the tissue itself (apart from microvasculature) is needed for accurate modeling of heat transfer. Accordingly this study presents a method and material characterization results that quantify the extent to which mechanical compression alters thermal conductivity, specific heat capacity, and thermal diffusivity of a polyacrylamide-based TMM. Cylindrical test specimens were cast from polyacrylamide material with diameter of 50 mm and height of 45 mm. Compression was applied using custom apparatus for applying prescribed uniaxial displacement, with a modular configuration for testing under ambient temperature as well as on a hot plate. Compression force at room temperature was measured with a load cell that was positioned in-line between compression plates. Prescribed heat flux was delivered based on power input, as quantified with the use of a reference sample in a thermal resistance network. Temperature was measured by an array of thermocouples. Software simulations were performed using finite element analysis (FEA) for structural deformation and computational fluid dynamics (CFD) for heat transfer under the combined effects of conduction and convection. The simulations provided estimates of deformed shape and thermal losses that were compared to experimental measurements. Mechanical stress-strain tests using three TMM replicate specimens at room temperature showed a linear stress-strain relationship from approximately 2% to 14% strain and a compressive modulus of elasticity ranging from 7.56 kPa to 12.7 kPa. Distributed temperature measurements under an imposed heat flux resulted in thermal conductivity between 0.89 W/(m·K) and 1.04 W/(m·K), specific heat capacity between 5590 J/(kg·K) and 6720 J/(kg·K) and thermal diffusivity between 1.29 × 10−7 m 2 /s to 1.71 × 10−7 m2/ s. Viscoelastic effects were observed to reach steady state after approximately 20 seconds, with full elastic recovery upon unloading. Thermal conductivity and thermal diffusivity were observed to decrease under mechanical compression, while specific heat capacity was observed to increase. The results affirm that thermal properties of tissue-mimicking material can be altered by mechanical compression. These findings can be applied to future investigation of temperature distribution during localized ablation by methods such as HIFU, and can be extended to refined material modeling of perfused tissue under compression.

Electron Microscope study of commensurate-incommensurate phase transition in BaZnGeO4

1990 ◽  
Vol 48 (4) ◽  
pp. 172-173
Author(s):  
Naoki Yamamoto ◽  
Makoto Kikuchi ◽  
Tooru Atake ◽  
Akihiro Hamano ◽  
Yasutoshi Saito
Keyword(s):  
Phase Transition ◽  
Electron Microscope Study ◽  
Room Temperature ◽  
Hexagonal Lattice ◽  
Ferroelectric Materials ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Periodic Arrays ◽  
Modulation Wave Vector

BaZnGeO4 undergoes many phase transitions from I to V phase. The highest temperature phase I has a BaAl2O4 type structure with a hexagonal lattice. Recent X-ray diffraction study showed that the incommensurate (IC) lattice modulation appears along the c axis in the III and IV phases with a period of about 4c, and a commensurate (C) phase with a modulated period of 4c exists between the III and IV phases in the narrow temperature region (—58°C to —47°C on cooling), called the III' phase. The modulations in the IC phases are considered displacive type, but the detailed structures have not been studied. It is also not clear whether the modulation changes into periodic arrays of discommensurations (DC’s) near the III-III' and IV-V phase transition temperature as found in the ferroelectric materials such as Rb2ZnCl4.At room temperature (III phase) satellite reflections were seen around the fundamental reflections in a diffraction pattern (Fig.1) and they aligned along a certain direction deviated from the c* direction, which indicates that the modulation wave vector q tilts from the c* axis. The tilt angle is about 2 degree at room temperature and depends on temperature.

Survival of mouse blastocysts after low-temperature preservation under high pressure

2004 ◽  
Vol 52 (4) ◽  
pp. 479-487 ◽  
Author(s):  
Cs. Pribenszky ◽  
M. Molnár ◽  
S. Cseh ◽  
L. Solti
Keyword(s):  
Phase Transition ◽  
Hydrostatic Pressure ◽  
Low Temperature ◽  
High Hydrostatic Pressure ◽  
Room Temperature ◽  
Freezing Point ◽  
Significant Loss ◽  
Embryo Cryopreservation ◽  
Subzero Temperatures ◽  
Survival Capacity

Cryoinjuries are almost inevitable during the freezing of embryos. The present study examines the possibility of using high hydrostatic pressure to reduce substantially the freezing point of the embryo-holding solution, in order to preserve embryos at subzero temperatures, thus avoiding all the disadvantages of freezing. The pressure of 210 MPa lowers the phase transition temperature of water to -21°C. According to the results of this study, embryos can survive in high hydrostatic pressure environment at room temperature; the time embryos spend under pressure without significant loss in their survival could be lengthened by gradual decompression. Pressurisation at 0°C significantly reduced the survival capacity of the embryos; gradual decompression had no beneficial effect on survival at that stage. Based on the findings, the use of the phenomena is not applicable in this form, since pressure and low temperature together proved to be lethal to the embryos in these experiments. The application of hydrostatic pressure in embryo cryopreservation requires more detailed research, although the experience gained in this study can be applied usefully in different circumstances.

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