The Thermal Properties of Human Blood during the Freezing Process

1973 ◽  
Vol 95 (2) ◽  
pp. 246-249 ◽  
Author(s):  
F. C. Wessling ◽  
P. L. Blackshear
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Water Solution ◽  
Time History ◽  
Steel Tube ◽  
Ice Crystals ◽  
Freezing Process ◽  
Stainless Steel Tube ◽  
History Of ◽  
Temperature Time

This paper presents calculations of the density, thermal conductivity, and enthalpy of blood during the freezing process. The calculations are based upon the premise that blood freezes similarly to a mixture of fats, proteins, and sodium chloride in a water solution and freezes so that ice crystals align themselves with the direction of heat flow. The properties were checked by calculating the theoretical temperature–time history of blood freezing in a Teflon-coated stainless-steel tube and comparing the results with experiments. The agreement was within 10 percent over the entire ranges of temperature and time. Hence the derived thermal properties are concluded to be good approximations to the real properties.

scholarly journals Estimations on Properties of Redox Reactions to Electrical Energy and Storage Device of Thermoelectric Pipe (TEP) Using Polymeric Nanofluids

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1812
Author(s):  
Qin Gang ◽  
Rong-Tsu Wang ◽  
Jung-Chang Wang
Keyword(s):  
Thermal Conductivity ◽  
Power Density ◽  
Heat Dissipation ◽  
Electrical Energy ◽  
Steel Tube ◽  
Storage Device ◽  
Stainless Steel Tube ◽  
The Novel ◽  
Empirical Formulas ◽  
Dissipative Heat

A thermoelectric pipe (TEP) is constructed by tubular graphite electrodes, Teflon material, and stainless-steel tube containing polymeric nanofluids as electrolytes in this study. Heat dissipation and power generation (generating capacity) are both fulfilled with temperature difference via the thermal-electrochemistry and redox reaction effects of polymeric nanofluids. The notion of TEP is to recover the dissipative heat from the heat capacity generated by the relevant machine systems. The thermal conductivity and power density empirical formulas of the novel TEP were derived through the intelligent dimensional analysis with thermoelectric experiments and evaluated at temperatures between 25 and 100 °C and vacuum pressures between 400 and 760 torr. The results revealed that the polymeric nanofluids composed of titanium dioxide (TiO2) nanoparticles with 0.2 wt.% sodium hydroxide (NaOH) of the novel TEP have the best thermoelectric performance among these electrolytes, including TiO2 nanofluid, TiO2 nanofluid with 0.2 wt.% NaOH, deionized water, and seawater. Furthermore, the thermal conductivity and power density of the novel TEP are 203.1 W/(m·K) and 21.16 W/m3, respectively.

Run-on in Gasoline Engines

1968 ◽  
Vol 183 (1) ◽  
pp. 21-51 ◽  
Author(s):  
W. S. Affleck
Keyword(s):  
Combustion Chamber ◽  
Time History ◽  
Spontaneous Ignition ◽  
Research Octane Number ◽  
Gasoline Engines ◽  
Engine Cooling ◽  
History Of ◽  
Valve Overlap ◽  
Temperature Time ◽  
Small Valve

When the ignition of a car engine is switched off, the engine normally comes to rest within a few revolutions but, occasionally, it may continue to fire erratically for a few seconds or longer. This phenomenon is known as run-on and, for the majority of European engines, is the result of spontaneous ignition of the fuel-air mixture in the combustion chamber. Part 1 of this paper describes experiments in a single-cylinder research engine which have been made to establish the principles controlling run-on. In particular the effects of air/fuel ratio, the nature of the fuel and the pressure-temperature-time history of the fuel-air mixture in the combustion chamber have been studied, as it is known that these factors play an important part in spontaneous ignition in experiments in laboratory vessels. From these observations it has been possible to formulate a theoretical model of the run-on process which explains the salient features of the phenomenon. In particular, it shows how the gradual cooling of the engine limits the duration of run-on and also how the duration of run-on may be considered as a measure of the extent to which fuel or engine factors must be altered to eliminate run-on. Part 2 describes the application of these principles to car engines using normal commercial-type fuels. It is concluded that the following are important features in the control of run-on: the use of fuel of sufficiently high Research octane number, minimum opening of throttle at idle, sufficient time for cooling of the combustion chamber before the ignition is switched off, efficient engine cooling, and small valve overlap. Current devices for reducing exhaust emissions are likely, through their effects on these features, to increase the tendency of an engine run-on. Combustion chamber deposits, though, appear to have little influence.

scholarly journals Extracting Concrete Thermal Characteristics from Temperature Time History of RC Column Exposed to Standard Fire

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Jung J. Kim ◽  
Kwang-Soo Youm ◽  
Mahmoud M. Reda Taha
Keyword(s):  
Thermal Conductivity ◽  
Numerical Method ◽  
Thermal Equilibrium ◽  
Time History ◽  
Radiant Heat Transfer ◽  
Unsteady State ◽  
Temperature Variations ◽  
Rc Column ◽  
Standard Fire ◽  
History Of

A numerical method to identify thermal conductivity from time history of one-dimensional temperature variations in thermal unsteady-state is proposed. The numerical method considers the change of specific heat and thermal conductivity with respect to temperature. Fire test of reinforced concrete (RC) columns was conducted using a standard fire to obtain time history of temperature variations in the column section. A thermal equilibrium model in unsteady-state condition was developed. The thermal conductivity of concrete was then determined by optimizing the numerical solution of the model to meet the observed time history of temperature variations. The determined thermal conductivity with respect to temperature was then verified against standard thermal conductivity measurements of concrete bricks. It is concluded that the proposed method can be used to conservatively estimate thermal conductivity of concrete for design purpose. Finally, the thermal radiation properties of concrete for the RC column were estimated from the thermal equilibrium at the surface of the column. The radiant heat transfer ratio of concrete representing absorptivity to emissivity ratio of concrete during fire was evaluated and is suggested as a concrete criterion that can be used in fire safety assessment.

scholarly journals Moving the pulsed heating technique beyond monolithic specimens: Experiments with coated wires

2001 ◽  
Vol 16 (8) ◽  
pp. 2421-2428 ◽  
Author(s):  
D. Josell ◽  
D. Basak ◽  
J. L. McClure ◽  
U. R. Kattner ◽  
M. E. Williams ◽  
...  
Keyword(s):  
Single Phase ◽  
Time History ◽  
Standard Technique ◽  
Black Body ◽  
Spectral Emissivity ◽  
Melting Temperatures ◽  
Pulsed Heating ◽  
History Of ◽  
Coated Wires ◽  
Temperature Time

Pulsed heating experiments that measure high-temperature thermophysical properties using pyrometric measurement of the temperature–time history of metal specimens rapidly heated by passage of electric current have a 30-year history at the National Institute of Standards and Technology. In recent years, efforts have been made to move beyond the limitations of the standard technique of using costly, black-body geometry specimens. Specifically, simultaneous polarimetry measurement of the spectral emissivity has permitted study of sheet and wire specimens. This paper presents the results of two efforts to expand beyond the macroscopically monolithic, single-phase materials of all previous studies. In the first study the melting temperatures of coatings, including Ti and Ti(Al) alloys, deposited on higher melting Mo substrates are measured. In the second study the melting temperatures of substrates, Ti and Cr, covered by higher melting W and Mo coatings are measured.

Residual Stresses During Coating Generation: Plasma Sprayed Alumina Coating on XC38 Measurements and Calculations

1998 ◽  
Author(s):  
A.C. Leger ◽  
A. Haddadi ◽  
B. Pateyron ◽  
G. Delluc ◽  
A. Grimaud ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Time History ◽  
Alumina Coating ◽  
Thin Coatings ◽  
Preheating Temperature ◽  
History Of ◽  
Substrate Preheating ◽  
Plasma Sprayed ◽  
Thick Coatings ◽  
Temperature Time

Abstract A simplified ID model has been developed to calculate the temperature time history of alumina layering splats. The splats were obtained by plasma spraying alumina fused and crushed particles (- 45 + 22 µm). The model has shown that for more than 160-200 µm layered splats the solidification time is over 7-10 µs, When spraying thin passes (ep < 15 µm) each splat cools down to substrate preheating temperature before next splat impacts. On the contrary for thick passes (ep = 60 or 180 µm), after depositing a certain thickness (between 160 and 200 µm) depending on spraying conditions, the temperature of the splats never drops below 800-900 K (mean splat temperature). In this case nucleation occurs after flattening is completed. Such conditions allow a columnar growth through the layered splats of each pass and successive passes. The study of the corresponding stresses (quenching σq and expansion mismatch) generated when spraying alumina on XC38 sheet was measured by following continuously the bending of a beam. The comparison of the measurements with the results of a ID model developed by Tsui and Clyne has allowed to calculate the coating Young's modulus Ed and the residual stresses difference at the interface. For thin coatings σq and Ed increase with preheating temperature. For thick coatings the values of Ed and σq are lower than the highest ones of thin coatings. This is probably due to stress relaxation by cracks propagation, the quenching and expansion mismatch stresses increasing with the increasing mean splat temperature.

Chemical Solidification Stress Calculation and Experiment of Concrete-Filled Steel Tube

2011 ◽  
Vol 117-119 ◽  
pp. 467-470
Author(s):  
Zhi Fu Yang ◽  
Qing Yuan Meng ◽  
Bing Zhao
Keyword(s):  
Circumferential Strain ◽  
Time History ◽  
Solidification Process ◽  
Computational Procedure ◽  
Steel Tube ◽  
Concrete Filled Steel Tube ◽  
Testing Facility ◽  
Calculation Results ◽  
History Of ◽  
Good Agreement

Nowadays concrete-filled steel tube is widely used as a building structure. For concrete added with expanding agent, certain stresses will be produced during the solidification process. This is due to the fact that concrete solidification can not be conducted freely by the constraints of the steel tube. An algorithm of computational procedure for concrete chemical solidification stresses has been proposed, and an incremental calculation formula is derived in this paper. In addition, a testing facility has been designed and conducted to measure the circumferential strain during the solidification process. The calculation results are in good agreement with experimental data. The results show that the chemical solidification stress of concrete filled steel tube is not only related to the geometrical size of the structure and expanding rate of the concrete, but also related to the time history of expansion process. It is found that the stresses will become larger if the concrete expansion occurs later under the condition of identical expansion rates of the concretes.

Variation of antiphase domain size in omphacite: A tool to determine the temperature–time history of eclogites revisited

2003 ◽  
Vol 88 (8-9) ◽  
pp. 1300-1311 ◽  
Author(s):  
Frank E. Brenker ◽  
Wolfgang Friedrich Müller ◽  
Gerhard P. Brey
Keyword(s):  
Time History ◽  
Domain Size ◽  
Antiphase Domain ◽  
History Of ◽  
Temperature Time
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