scholarly journals The thermal and electrical conductivities of some pure metals

1925 ◽  
Vol 107 (742) ◽  
pp. 206-227 ◽  
Keyword(s):  
Absolute Temperature ◽  
Independent Method ◽  
Electron Theory ◽  
Slight Tendency ◽  
Electrical Conductivities ◽  
Long Time ◽  
Series Of Experiments ◽  
Pure Metals ◽  
The Absolute ◽  
Experimental Values

The relation between the thermal and electrical conductivities of me has for a long time engaged the attention of physicists. As far back as 1 Wiedemann and Franz propounded the law to the effect that the ratio of two conductivities was the same for all metals. In 1872 Lorenz, both on retical and experimental grounds, sought to establish that the above-mentio ratio was proportional to the absolute temperature. On the development the electron theory Drude, H. A. Lorentz, J. J. Thomson and others ha on the basis of various assumptions, arrived at the same conclusion as Lon Up to 1900, however, the experimental values were too uncertain to allow definite confirmation of the theory. In that year Jaeger and Diesselho published the result of their investigation, which gave directly the ratio of conductivities for a number of metals and alloys over the range 18° to 100° Lees has since, by an independent method, confirmed the values of Jaeger Diesselhorst for a number of metals at 18° C. and has carried the investigat own to —170° C. Meissner has experimented with some pure metals down —250° C. and Onnes and Holst even lower. The result of these investigations has been to show that between —100° C. + 100° C. the value of the function K/ λ T (K and λ being the thermal and ectrical conductivities and T the absolute temperature), is sensibly the samer the pure metals, with perhaps a slight tendency to fall with decreasing temrature. Below —100° C., however, the function shows an increasingly rapid with temperature and a considerable divergence between individual metals, ove a temperature of + 100° C. very few determinations of thermal conictivity have been made, and the object of the present series of experiments is been to measure, in this region, the thermal and electrical conductivities a number of metals of the highest purity obtainable commercially.

THE ELECTRICAL CONDUCTIVITY OF MOLTEN OXIDES

1953 ◽  
Vol 31 (11) ◽  
pp. 1009-1019 ◽  
Author(s):  
A. E. Van Arkel ◽  
E. A. Flood ◽  
Norman F. H. Bright
Keyword(s):  
Experimental Data ◽  
Electrical Conductivity ◽  
Absolute Temperature ◽  
Molten State ◽  
Melting Points ◽  
Electrical Conductivities ◽  
The Absolute ◽  
Pattern Of Variation ◽  
Molten Oxides

Electrical conductivities of some molten oxides have been determined. In order of decreasing equivalent conductances at their melting points the oxides investigated were: Li2O, PbO, TeO2, MoO3, Bi2O3, V2O5, Sb2O3, and CrO3. The variation of the observed values of the specific conductivities, K, with the absolute temperature, T, can be described by an equation of the form,[Formula: see text]where A, B, C, etc. are constants. While the experimental data are adequately described by an equation of this form containing only the constants A and B, a slightly better fit is obtained using three constants. The conductivities of the molten oxides follow a pattern of variation from element to element which is substantially the same as that of the molten halides. For elements giving more than one oxide stable in the molten state, the oxide corresponding to the highest state of valency has the lowest conductivity.

The thermo-electric behaviour of tin and silver at liquid-helium temperatures

1953 ◽  
Vol 217 (1129) ◽  
pp. 280-293 ◽  
Keyword(s):  
Transition Temperature ◽  
Electric Power ◽  
Liquid Helium ◽  
Superconducting State ◽  
Absolute Temperature ◽  
Superconducting Transition ◽  
Electron Theory ◽  
Thermo Electric ◽  
The Absolute ◽  
Highly Strained

A new method, employing a superconducting galvanometer and requiring a temperature difference of only 0·01° K between the ends of the specimen, has been used to measure the absolute thermo-electric powers of tin and silver at liquid-helium temperatures. It has been shown that the thermo-electric power of tin vanishes abruptly at the superconducting transition temperature; this observation disagrees with the conclusions of Casimir & Rademakers, who report a curious behaviour above the transition temperature which they hold to ‘foreshadow’ the onset of superconductivity. The thermo-electric behaviour of metals in the normal (non-superconducting) state shows striking disagreement with the predictions of the free-electron theory. Thus, the thermo-electric power does not vary linearly with the absolute temperature, and for silver has a positive, instead of a negative, sign. The thermo-electric power is profoundly influenced by the presence of strains in the specimen, and by very small amounts of impurity, the temperature dependence becoming more nearly linear for impure or highly strained specimens. A marked anisotropy has been found in the thermo-electric behaviour of single crystals of tin.

scholarly journals The effect of hydrogen on the discharge of negative electricity from hot platinum

1908 ◽  
Vol 80 (540) ◽  
pp. 379-382
Keyword(s):  
Constant Temperature ◽  
Absolute Temperature ◽  
Great Length ◽  
Series Of Experiments ◽  
The Absolute ◽  
The Wire

The effect of hydrogen on the discharge of negative electricity from hot platinum was examined by the writer in 1903; it was found to produce a very large increase in the current. The experiments were all done with nearly new platinum wires which had not been heated in the gas for any great length of time, because it was known that long-continued heating causes the wire to disintegrate. The present paper contains an account of a series of experiments in which wires were heated for long periods in hydrogen, so that any changes in the effect of the hydrogen could be observed. It appears that continued heating in hydrogen alters the character of the effects observed so that the behaviour of an old wire may be very different from that of a new one. The following gives a short abstract of each section of the paper:— 1. Assuming that x = B p n , where x denotes the current per square centimetre of platinum at constant temperature, p is the pressure of the hydrogen, and B and n are quantities depending only on the temperature, and also that x = A θ ½ e –Q/2θ , where θ denotes the absolute temperature and A and Q depend only on the pressure; it is proved that: (1) n xθ -1– c , where α and c are constants; (2) Q = P — 2 α log p ; and (3) A = K p -c . These equations are shown to agree with the observations.

The specific heats of three paramagnetic salts at very low temperatures

1956 ◽  
Vol 237 (1210) ◽  
pp. 395-403 ◽  
Keyword(s):  
Specific Heat ◽  
Absolute Temperature ◽  
Magnesium Nitrate ◽  
Paramagnetic Resonance ◽  
Specific Heats ◽  
Ammonium Alum ◽  
Relaxation Measurements ◽  
Ferric Ammonium ◽  
The Absolute ◽  
Measured Specific Heat

The specific heats of three paramagnetic salts, neodymium magnesium nitrate, manganous ammonium sulphate and ferric ammonium alum, have been measured at temperatures below 1°K using the method of γ -ray heating. The temperature measurements were made in the first instance in terms of the magnetic susceptibilities of the salts, the relation of the susceptibility to the absolute temperature having been determined for each salt in earlier experiments. The γ -ray heatings gave the specific heat in arbitrary units. The absolute values of the specific heats were found by extrapolating the results of paramagnetic relaxation measurements at higher temperatures. The measured specific heat of neodymium magnesium nitrate is compared with the value calculated from paramagnetic resonance data, and good agreement is found.

A Fluidity-Temperature Relationship for Liquids

1973 ◽  
Vol 95 (2) ◽  
pp. 236-241
Author(s):  
T. F. Ford ◽  
C. R. Singleterry
Keyword(s):  
Interpolation Formula ◽  
Absolute Temperature ◽  
Temperature Relationship ◽  
Organic Liquids ◽  
Low Viscosity ◽  
Linear Relationships ◽  
Temperature Ranges ◽  
The Absolute ◽  
The Relationship

Many relationships between viscosity or its reciprocal, fluidity, and temperature have been proposed for liquids. None except the empirically modified ASTM chart have proven satisfactory over extended temperature ranges. We here note that by plotting the kinematic fluidity (φkin) against the square of the absolute temperature (deg K2) we obtain linear relationships for a wide variety of organic liquids at kinematic viscosities less than about 1.67 centistokes (or fluidities above about 0.60 reciprocal centistokes). The generality of the relationship appears to justify the use of the equation, φkin=a+bT2, as an interpolation formula for organic liquids in the low viscosity region.

scholarly journals The Excess Secular Change in the Obliquity of the Ecliptic and Its Relation to the Internal Motion of the Earth

1972 ◽  
Vol 48 ◽  
pp. 192-195 ◽  
Author(s):  
Chuichi Kakuta ◽  
Shinko Aoki
Keyword(s):  
Time Variation ◽  
Rotational Speed ◽  
Internal Motion ◽  
Secular Change ◽  
Electrically Conducting ◽  
The Core ◽  
The Earth ◽  
Fluid Core ◽  
Electrical Conductivities ◽  
Long Time

The previous result (Aoki, 1969) on the explanation of the excess secular change in the obliquity of the ecliptic frictional couplings in the rigid constituents, the mantle and the core, is extended by using a model of an elastic and electrically conducting mantle and a hydromagnetic core. The secular change of the obliquity of the ecliptic referred to the mantle is found to be 1/3.2 times of the observed value, if the electrical conductivities of the fluid core and the mantle are assumed to be 3·10−6 emu and 3·10−9 emu respectively. A large secular deceleration of the Earth's rotational speed obtained in the previous result is proved to be strongly reduced because of weak excitation of the perturbing potential for a long time variation.

scholarly journals Topical issues in the study of the early Aeneolithic of the Don forest-steppe (chronology, periodization, synchronization)

2019 ◽  
Vol 8 (2) ◽  
pp. 215-220
Author(s):  
Andrey Mikhailovich Skorobogatov
Keyword(s):  
Forest Steppe ◽  
Stone Age ◽  
East European ◽  
Relevant Today ◽  
Long Time ◽  
Absolute Dating ◽  
The Absolute ◽  
Tripolye Culture

For a long time, the Eneolithic of the Don forest-steppe remained one of the least studied epochs in the archaeological scheme of the region. However, since the late 1960s, sites with materials of the Eneolithic have been actively explored on the territory of the Voronezh and Lipetsk Regions. By the 1980s, researchers had a concept for the development of copper-stone age cultures within the system of the Mariupol cultural-historical region of the Dnieper-Don-Ural interfluve, which is still relevant today. The criteria for distinguishing the Eneolithic era in the steppe and forest-steppe spaces of the East European steppe and forest-steppe were substantiated. The idea of their synchronization with complexes of the Tripolye A period was designated. The early Eneolithic in the Don forest-steppe was marked by the appearance of a population with specific ceramics of Nizhnedonskaya culture. Questions of the chronology of the early Eneolithic were solved exclusively by methods of analogies with the materials of neighboring territories and synchronization with the local Neolithic complexes. The paper deals with the problems of chronology, periodization and synchronization of materials from the early Aeneolithic of the territory of the Don forest-steppe. The focus is on the absolute dating of the Nizhnedonskaya culture of the Mariupol cultural-historical region and its synchronization with the early Tripolye Culture. According to all the data available to date, the regions early Eneolithic can be dated from 5300 to 4250 BC.

scholarly journals Absolute temperature directly from plank’s profile: A simulation

2021 ◽  
Vol 33 (2) ◽  
pp. 9-19
Author(s):  
V. VIJAYAKUMAR ◽  
Keyword(s):  
Thermal Radiation ◽  
Response Function ◽  
Wave Length ◽  
Absolute Temperature ◽  
Scale Factor ◽  
Material Surface ◽  
Measured Spectrum ◽  
The Absolute

The measured thermal radiation from a material surface will, in general, have a wave length (\lambda) dependent scale-factor to the Planck profile (PT) from the contributions of the emissivity (Є\lambda) of the surface, the response function (A\lambda) of the measurement setup, and the emission via non-Plank processes. For obtaining the absolute temperature from such a profile, a procedure that take care of these dependencies and which relay on a temperature grid searchis proposed. In the procedure, the deviation between the Plank profiles at various temperatures and the measured spectrum that is made equal to it at a selected wavelength, by scaling, is used. The response function (A\lambda) is eliminated at the measurement stage and the polynomial dependence of the remnant scale factor mostly dominated by Є\lambda) i s extracted from the measured spectrum by identifying its optimal \lambda dependence. It is shown that when such a computation is carried out over a temperature grid, the absolute temperature can be identified from the minimum of the above deviation. Here, search for T and Є\lambda) d elinked, unlike in the leastsquare approaches that are normally employed. Code that implements the procedure is tested with simulated Planck profile to which different viable values of Є\lambda) a nd noise is incorporated. It shown that if the \lambda dependence of scale-factor is not too high, the absolute temperature can be recovered. A large \lambda dependent scale-factor and the consequent possible error in the temperature obtained can also be identified.

scholarly journals The basic characteristics of the Belgrade’s heat island

2003 ◽  
Vol 83 (1) ◽  
pp. 15-30 ◽  
Author(s):  
Goran Andjelkovic
Keyword(s):  
Air Temperature ◽  
Space Structure ◽  
Absolute Temperature ◽  
Heat Island ◽  
Temperature Minimum ◽  
City Center ◽  
Climatic Period ◽  
Average Annual Temperature ◽  
The Absolute ◽  
The City

The urban heat island, as a phenomenon due to the higher air temperature in the cities as compared to their immediate surroundings, represents the most important consequence of the urbanization influence on the topoclimate. As compared to the smaller cities in its surroundings, Belgrade's average annual temperature is from 0,4 to 1,0 ?C higher (period 1961-1990). A very liable index of the Belgrade's heat island is the air temperature measured at the airport in Surcin. In the period from 1971-1990. average annual air temperature at the airport was 11,2 ?C, and in the city center it was 0,7 ?C higher. Belgrade has a higher absolute minimal temperature than its surroundings during every month. In the last climatic period the absolute temperature minimum in Belgrade was even 5,4 ?C higher than the highest value measured within this parameter in its wider surroundings (Veliko Gradiste -26,4 ?C). In the above mentioned twenty years period the absolute air temperature minimum in Surcin was -26,0 ?C, and in the city center only -18,2 ?C. The number of the frosty days at the airport was 77,8, and in Belgrade 58,2. Although the heat island of Belgrade was formed together with formation of the city, it was more evident at the beginning of the 20th century (0,4 ?C). During the next five to six decades a faster intensity growth was recorded (up to 0,9 ?C). This coincides with the period of the population growth as well as with development of the city activities, industry above all. During one year the intensity of the Belgrade's heat island reached its maximum in winter. In January the city, as compared to Surcin, was warmer for about 1,0 ?C, and in September for only 0,1 ?C. The daily variations of the heat island are such that it reaches its highest intensity during the evening hours (at 9 p.m. 0,9 ?C). If the average values of the extreme daily temperatures are being examined, one can see a distinct difference: average city minimums are 1,5 ?C higher than the airport minimums, while the maximums are only 0,2 ?C higher. During winter, in concrete anticyclonic conditions, it can be 10 ?C warmer in the city than in the immediate surroundings. Together with the perennial growth of heat island intensity, its "space range" also expands. The space structure of the heat island is very distinct. Exceptions in the temperature values between certain points of measurements in the winter morning hours can go up to 6-8 ?C.

scholarly journals Well-being and Sustainable Development of Mining Regions: the Universal Basic Income

2019 ◽  
Vol 105 ◽  
pp. 04035
Author(s):  
Oleg Mazavin ◽  
Mikhail Kaz ◽  
Irina Roshchina
Keyword(s):  
Social Insurance ◽  
Historical Context ◽  
Well Being ◽  
Point Of View ◽  
Economic Research ◽  
Basic Income ◽  
Long Time ◽  
Series Of Experiments ◽  
The One ◽  
Mining Regions

The article presents the results of the analysis of the practice of implementation the concept of universal basic income. It is shown that in estimating the results of a series of experiments in this field, conducted in a number of countries, it is recommended to abandon the approach based on the positivist point of view. For a long time, it dominated science in general and economic research in particular, but it continues to influence many researchers today. This conclusion should be taken into account in the formation of the structure and composition of regions’ welfare indices. The research materials are placed in a broad historical context. On the one hand, this made it possible to more vividly present the prerequisites, characteristics and consequences of repeated attempts to introduce universal basic income into the practice of social insurance, undertaken in different countries of the world (Finland, Canada, Kenya, Iran, India, USA). On the other hand, to reveal the possibilities and problems of using universal basic income as a tool to help overcome the dysfunctional development of certain territories, including mining regions.

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