THE THERMAL CONDUCTIVITY OF NAPALM–GASOLINE GELS

1948 ◽  
Vol 26a (2) ◽  
pp. 50-59 ◽  
Author(s):  
G. O. Langstroth ◽  
F. Zeiler
Keyword(s):  
Thermal Conductivity ◽  
Temperature Coefficient ◽  
Small Diameter ◽  
Temperature Coefficient Of Resistance ◽  
Simple Method ◽  
Viscous Liquids ◽  
Low Viscosity ◽  
Tungsten Filaments ◽  
Better Than

A slightly modified form of the rapid and simple method suggested by Hutchinson for the measurement of the thermal conductivity of liquids has been found to suffer from convection effects with samples of low viscosity, except with conductivity tubes of very small diameter. For more viscous liquids such as glycerol it was found to be adequate under all conditions studied. The method has been applied in the determination of the conductivity of Napalm–gasoline gels. For temperatures T between − 50° and 50 °C., and Napalm concentrations C between 0 and 10%, the conductivity k in cal. sec.−1 cm.−1 per degree C. is described to better than 1% by the relation, k × 105 = 29.7 − 0.068 T + 0.11 C. The temperature coefficient of resistance of the unaged tungsten filaments used in the tubes differed considerably from the value given by the International Critical Tables for aged tungsten filaments. For temperatures T0 between − 50° and 50 °C., the coefficient α0 per degree C. is given to better than 1% by the relation, [Formula: see text].

scholarly journals Simple Method for Estimating the Contribution of Neighbouring n-beam Interactions to Two-beam Structure Factors

1988 ◽  
Vol 41 (3) ◽  
pp. 469
Author(s):  
HJ Juretschke ◽  
HK Wagenfeld
Keyword(s):  
Experimental Determination ◽  
Structure Factor ◽  
Beam Structure ◽  
Simple Method ◽  
Experimental Configuration ◽  
Structure Factors ◽  
Special Cases ◽  
Better Than

Unless special precautions are taken, the experimental determination of two-beam structure factors to better than 1 % may include contributions from neighbouring n-beam interactions. In any particular experimental configuration, corrections for such contributions are easily carried out using the modified two-beam structure factor formalism developed recently (Juretschke 1984), once the full indexing of the pertinent n-beam interactions is known. The method is illustrated for both weak and strong primary reflections and its applicability in special cases, as well as for less than perfect crystals, is discussed.

REACTIONS OF ARYLSULPHONIC ESTERS: VII. THE HEAT CAPACITY OF ACTIVATION FOR THE ETHANOLYSIS OF METHYL p-NITROBENZENESULPHONATE

1957 ◽  
Vol 35 (7) ◽  
pp. 623-629 ◽  
Author(s):  
J. B. Hyne ◽  
R. E. Robertson
Keyword(s):  
Heat Capacity ◽  
Temperature Coefficient ◽  
Nonaqueous Media ◽  
Conductometric Method ◽  
Better Than

A conductometric method is described for the determination of rates of solvolyses in nonaqueous media with an accuracy of better than ± 0.5% in k. The heat of activation derived from the results so obtained is shown to have a temperature coefficient (ΔCp‡) of −21 cal./mole deg.

A Simple Method for Determination of Thermal Conductivity Coefficients of Thin Films

2001 ◽  
Author(s):  
Chi Hsiang Pan ◽  
Chien Li Tung
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Thermal Conductivity Coefficient ◽  
Crystalline Silicon ◽  
Silicon Film ◽  
Simple Method ◽  
Active Devices ◽  
Analytical Expressions

Abstract In this paper, we present a simple method to determine thermal conductivity coefficients (TCC) of thin films with a compact characterization microstructure and by using common measuring apparatus. The microstructure can be fabricated by a simple surface micromachining technique and in situ along with active devices on the same chip. Analytical expressions are derived to calculate the thermal conductivity coefficients of thin films from the experimental data. Experimental results with a heavily n-doped LPCVD poly crystalline silicon film are used herein to demonstrate the effectiveness of the proposed method. The obtained thermal conductivity coefficient seems to decrease a little as temperature increase and the average is around 39 Wm−1 °C−1 at 400°C below.

Experimental Determination of Temperature-Dependent Thermal Conductivity of Solid Eicosane-Based Nanostructure-Enhanced Phase Change Materials

2012 ◽  
Author(s):  
Mahdi Nabil ◽  
J. M. Khodadadi
Keyword(s):  
Thermal Conductivity ◽  
Phase Change Materials ◽  
Small Diameter ◽  
Copper Oxide Nanoparticles ◽  
Water Bath ◽  
Conductivity Data ◽  
Vacuum Oven ◽  
Thermal Conductivity Data ◽  
Ice Water

The effective thermal conductivity of composites of eicosane and copper oxide nanoparticles in the solid state was measured experimentally by using the transient plane source technique. Utilizing a controllable temperature bath, measurements were conducted at various temperatures between 10 and 35°C for the solid samples. In the course of preparation of the solid specimen, liquid samples (0, 1, 2, 5 and 10 wt%) were poured into small diameter molds and were degased within a vacuum oven. The molds were then subjected to either ambient solidification or ice-water bath freezing method. Measured thermal conductivity data of the composites were found to be nearly independent of the measurement temperature for a given loading of CuO nanoparticles regardless of the solidification procedure. Irrespective of the solidification method, as the melting temperature was approached, thermal conductivity data of the solid disks rose sharply for both sets of experiments. The composites prepared using the ice-water bath solidification scheme consistently exhibited lower values of thermal conductivity when compared to the samples which prepared under ambient solidification method. This behavior might be due to the greater void percentage of ice-water bath samples and/or crystal structure deviations due to phase transition method.

The HLM method: a simple way to get the solid–liquid phase diagrams and enthalpies of transition of pure components and mixtures

1992 ◽  
Vol 70 (11) ◽  
pp. 2745-2750 ◽  
Author(s):  
François Quirion ◽  
Daniel Lambert ◽  
Gérald Perron
Keyword(s):  
Differential Scanning Calorimetry ◽  
Chemical Engineering ◽  
Low Cost ◽  
Polymer Science ◽  
Scanning Calorimetry ◽  
Simple Method ◽  
Melting Temperatures ◽  
Solid Liquid ◽  
Better Than

A simple method of thermal analysis is described which gives the same information as differential scanning calorimetry. The method is based on the Heat-Leak-Modulus, HLM, of a sample cell placed in a constant temperature reservoir. In the present study, the HLM method is used for the investigation of pure components and mixtures from −190 to 50 °C. The method allows the determination of glass-transition, crystallizations, solid–solid transition, eutectic, and melting temperatures with a reproducibility better than ±0.1 °C. The enthalpy of a transition can be determined with a reproducibility of ±5%. The simplicity, the low cost, and the precision of the HLM method fills the gap between standard cooling curves and sophisticated differential scanning calorimetry experiments. The HLM method has numerous applications in physical chemistry, polymer science, metallurgy, and chemical engineering.

scholarly journals The thermal conductivities of oxygen and nitrogen

1928 ◽  
Vol 118 (780) ◽  
pp. 594-607 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Temperature Coefficient ◽  
Thermal Conduction ◽  
Standard Substance ◽  
The Absolute ◽  
Thermal Conductivities

The interest in the determination of the thermal conductivities of oxygen and nitrogen lies partly in their relation to the thermal conductivity of air. The latter is the medium which practically every experimenter on gaseous thermal conduction has investigated, and has therefore become the standard substance in this field of research. Being a mixture chiefly of the gases oxygen and nitrogen, with the latter in the greater proportion, the value of its conductivity should lie between those of oxygen and nitrogen and should be nearer that of nitrogen than that of oxygen. The authors, in common with Weber and Todd, have verified this experimentally, the only observer finding these con­ductivities in a contrary order being Winkelman, who used a cooling thermometer method. The following is a table of the results hitherto obtained for the absolute thermal conductivities at 0° C. of oxygen and nitrogen, together with their authors’ results for air. The values marked with an asterisk have been deduced by applying the temperature coefficient, 0.0029 per 0° C., to results which were obtained at temperatures above 0° C. Weber has recently published a new result for the thermal conductivity of air, 0.0000574, which is about 1 per cent. higher than his old value. Assuming that, if his results for oxygen and nitrogen were revised, they would be increased in the same proportion, his new values for these gases would be—oxygen 0.0000583, and nitrogen 0.0000572.

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