The Dependence of the Stress on the Temperature of Rubber Elongated to a Constant Degree

1939 ◽  
Vol 12 (3) ◽  
pp. 520-528 ◽  
Author(s):  
V. Hauk ◽  
W. Neumann
Keyword(s):  
Temperature Coefficient ◽  
Absolute Temperature ◽  
Experimental Results ◽  
Constant Degree ◽  
Vulcanized Rubber ◽  
The Absolute

Abstract An instrument for measuring stresses was constructed, whereby changes in tension brought about by changes in temperature in rubber maintained at constant elongation were measured. These measurements were carried out with three types of vulcanizates. After measures were taken in the case of weakly vulcanized samples to eliminate the disturbing factors arising from crystallization, the fact was established that stress is directly proportional to the absolute temperature for all types of vulcanized rubber, as required by theory. It is shown that under some conditions the stress-temperature coefficient depends on the degree of vulcanization, the coefficient decreasing with increase in the degree of vulcanization. The experimental results are discussed, and an explanation is offered to account for the dependence of the stress-temperature coefficient on the degree of vulcanization.

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.

The Oil Resistance of Rubber. I Study of the Swelling of Vulcanized Rubber

1936 ◽  
Vol 9 (1) ◽  
pp. 70-73
Author(s):  
Yoshio Tanaka ◽  
Shû Kambara ◽  
Jirô Noto
Keyword(s):  
Molecular Structure ◽  
Elastic Properties ◽  
Mixed Solvents ◽  
Experimental Results ◽  
Stress Strain ◽  
Oil Resistance ◽  
Effect Of Solvents ◽  
Vulcanized Rubber

Abstract To study the effect of solvents on the elastic properties of vulcanized rubber, the following three points were investigated. 1. The swelling maximum obtained by various mixed solvents. 2. The stress-strain curves of rubber swollen to different degrees. 3. Time-swelling and time-deswelling curves. The spiral theory of molecular structure of rubber proposed by Fikentscher and Mark is utilized to explain the experimental results.

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 The CBR frequency spectrum below 1 GHz recent results and new observations

1992 ◽  
Vol 9 ◽  
pp. 297-298
Author(s):  
G. Sironi ◽  
G. Bonelli ◽  
M. Gervasi
Keyword(s):  
Frequency Spectrum ◽  
Absolute Temperature ◽  
History Of ◽  
The Absolute ◽  
The Universe

AbstractWe are carrying on measurements of the absolute temperature of the CBR at various frequencies near and below 1 GHz, looking for so far undetected deviations from a planckian spectrum. The amplitude and frequency of those distortions can give precious information about the history of the Universe.

Spekktroskopische Untersuchungen in der Festkörperchemie, IX / Spectroscopic Investigations in the Solid-State Chemistry, IX

1975 ◽  
Vol 30 (3-4) ◽  
pp. 198-201 ◽  
Author(s):  
Paul K. Burkert ◽  
Frank Hutter ◽  
Detlev Koth
Keyword(s):  
Solid State ◽  
Temperature Dependence ◽  
Temperature Coefficient ◽  
Asymmetry Parameter ◽  
Lattice Parameters ◽  
Coupling Constants ◽  
Solid State Chemistry ◽  
Spectroscopic Investigations ◽  
Experimental Correlation ◽  
The Absolute

The four 185Re, 187Re—NQR-transitions of RbReO4 were measured. From the NQR-coupling constants, asymmetry-parameter and normal temperature-coefficient in the range of 77-300°K one can conclude, that the anomalons temperature dependence of the NQR-frequencies of NH4ReO4 is not caused by the absolute values of certain lattice parameters.An experimental correlation of the Re—NQR-coupling constants of scheelite-structured perrhenates with the length of the elementar cell was found and discussed.

The nuclear specific heat in paramagnetic cupric salts at temperatures below 1° K I. Thermodynamic measurements made from a study of the field-dependence of the adiabatic susceptibility

1950 ◽  
Vol 203 (1074) ◽  
pp. 375-391 ◽  
Keyword(s):  
Magnetic Susceptibility ◽  
Specific Heat ◽  
Field Dependence ◽  
Absolute Temperature ◽  
Potassium Sulphate ◽  
Specific Heats ◽  
Magnetic Cooling ◽  
Thermodynamic Measurements ◽  
Small Fields ◽  
The Absolute

Thermodynamic measurements have been made at temperatures below 1°K, obtained by the method of magnetic cooling, on copper potassium sulphate and on a diluted copper Tutton salt. A study has been made of the field- dependence (for small fields) of the adiabatic susceptibility of the cooled and thermally isolated salt, the measurements covering the range of temperature from 1°K down to 0.05°K for copper potassium sulphate, and to 0.025° K for the dilute salt. From these measurements the entropy and magnetic susceptibility are determined as functions of the absolute temperature. It is concluded that for both salts the susceptibility follows a Curie-Weiss law, the values of ∆ being 0.034 and 0.0048º K respectively; the specific heats are of the form ∆ / T 2 , the values found for A being 6.1x10 -4 R for copper potassium sulphate and 1.98x10 -4 R for the dilute salt.Deviations from this behaviour in a ferromagnetic direction are found for copper potassium sulphate below 0.07° K.

Numerical Simulation of Cavitating Flow in Mixed Flow Pump With Closed Type Impeller

2009 ◽  
Author(s):  
Katsutoshi Kobayashi ◽  
Yoshimasa Chiba
Keyword(s):  
Leading Edge ◽  
Suction Side ◽  
Experimental Results ◽  
Absolute Pressure ◽  
Pressure Side ◽  
Blade Surface ◽  
Mixed Flow ◽  
Closed Type ◽  
The Absolute ◽  
Flow Pump

LES (Large Eddy Simulation) with a cavitation model was performed to calculate an unsteady flow for a mixed flow pump with a closed type impeller. First, the comparison between the numerical and experimental results was done to evaluate a computational accuracy. Second, the torque acting on the blade was calculated by simulation to investigate how the cavitation caused the fluctuation of torque. The absolute pressure around the leading edge on the suction side of blade surface had positive impulsive peaks in both the numerical and experimental results. The simulation showed that those peaks were caused by the cavitaion which contracted and vanished around the leading edge. The absolute pressure was predicted by simulation with −10% error. The absolute pressure around the trailing edge on the suction side of blade surface had no impulsive peaks in both the numerical and experimental results, because the absolute pressure was 100 times higher than the saturated vapor pressure. The simulation results showed that the cavitation was generated around the throat, then contracted and finally vanished. The simulated pump had five throats and cavitation behaviors such as contraction and vanishing around five throats were different from each other. For instance, the cavitations around those five throats were not vanished at the same time. When the cavitation was contracted and finally vanished, the absolute pressure on the blade surface was increased. When the cavitation was contracted around the throat located on the pressure side of blade surface, the pressure became high on the pressure side of blade surface. It caused the 1.4 times higher impulsive peak in the torque than the averaged value. On the other hand, when the cavitation was contracted around the throat located on the suction side of blade surface, the pressure became high on the suction side of blade surface. It caused the 0.4 times lower impulsive peak in the torque than the averaged value. The cavitation around the throat caused the large fluctuation in torque acting on the blade.

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