The Compressibility of Rubber

1930 ◽  
Vol 3 (4) ◽  
pp. 555-562 ◽  
Author(s):  
L. H. Adams ◽  
R. E. Gibson
Keyword(s):  
High Pressures ◽  
Sulfur Compound ◽  
Reliable Estimate ◽  
Total Sulfur ◽  
Tetramethylthiuram Disulfide ◽  
Three Samples ◽  
Inorganic Fillers ◽  
A Minor ◽  
Low Pressures ◽  
Minor Correction

Abstract Although many of the elastic properties of rubber have been investigated with very interesting results, no measurements have been made, so far as we know, of its cubic compressibility at high pressures. Those measurements which have been made at low pressures yield results varying from 93×10−6 obtained by Clapeyron to an estimate of the order of the compressibility of bronze (about 1×10−6) given by Amagat. As the compressibility of rubber enters as a minor correction into most compressibility measurements at high pressures, it is very desirable to have a reliable estimate of its value. In this communication we propose to give the results of experimental determinations of the compressibility at 25° of three samples of rubber which were furnished to us by H. L. Curtis and A. H. Scott of the U. S. Bureau of Standards. The samples are described as follows: Sample A.—Hard rubber from panel made by the Goodrich Company. It is a rubber-sulfur compound containing no inorganic fillers. The total sulfur amounts to 27.4 per cent, of which 0.21 per cent, is free sulfur. The density is 1.149 at 27° C. Sample B.—A rubber-sulfur compound containing 90 per cent. smoked rubber and 10 per cent. sulfur and vulcanized 105 minutes at 300° F. Density = 0.990 at 25°. Sample C consists of pale crepe rubber 90.75 per cent., zinc oxide 5 per cent., sulfur 4 per cent., tetramethylthiuram disulfide 0.25 per cent. It was vulcanized for 30 minutes at 260° F. Density = 0.990 at 27°.

scholarly journals Roberts’ weak welfarism theorem: a minor correction

2021 ◽  
Author(s):  
Peter J. Hammond
Keyword(s):  
Euclidean Space ◽  
Social Welfare ◽  
Utility Function ◽  
Weak Continuity ◽  
Strict Preference ◽  
Counter Example ◽  
Independence Of Irrelevant Alternatives ◽  
Unrestricted Domain ◽  
A Minor ◽  
Minor Correction

AbstractRoberts’ “weak neutrality” or “weak welfarism” theorem concerns Sen social welfare functionals which are defined on an unrestricted domain of utility function profiles and satisfy independence of irrelevant alternatives, the Pareto condition, and a form of weak continuity. Roberts (Rev Econ Stud 47(2):421–439, 1980) claimed that the induced welfare ordering on social states has a one-way representation by a continuous, monotonic real-valued welfare function defined on the Euclidean space of interpersonal utility vectors—that is, an increase in this welfare function is sufficient, but may not be necessary, for social strict preference. A counter-example shows that weak continuity is insufficient; a minor strengthening to pairwise continuity is proposed instead and its sufficiency demonstrated.

scholarly journals Comparison of gas dehydration methods based on energy consumption

2016 ◽  
Vol 20 (2) ◽  
pp. 253-258
Author(s):  
B.S. Kinigoma ◽  
G.O. Ani
Keyword(s):  
Energy Consumption ◽  
Natural Gas ◽  
High Pressures ◽  
Energy Requirement ◽  
Chemical Properties ◽  
Triethylene Glycol ◽  
Design Engineers ◽  
Natural Gas Dehydration ◽  
Physical And Chemical ◽  
Low Pressures

This study compares three conventional methods of natural gas (Associated Natural Gas) dehydration to carry out the dehydration process and suitability of use on the basis of energy requirement. These methods are Triethylene Glycol (TEG) absorption, solid desiccant adsorption and condensation. Analyses performed were based on dehydration of Natural Gas saturated with 103Nm3/h water content at a temperature range of -10O C to 30oC, and gas pressure variation between 7MPa and 20MPa. This analysis and study showed that energy required for all three processes decreases with increase in pressure, but condensation dehydration requires the least energy at high pressures. Results obtained shows that, both at high pressures and low pressures, TEG dehydration is most suitable and in cases where very low Tdew is required, solid desiccant adsorption is preferable. In conclusion, the findings in this paper will aid natural gas process design engineers to decide on what method to use base  on energy consumption and on the physical and chemical properties of the final products.Keywords: Dehydration, Absorption, Desiccant, Condensation, Triethylene Glycol (TEG)

scholarly journals Sorption, Structure and Dynamics of CO2 and Ethane in Silicalite at High Pressure: A Combined Monte Carlo and Molecular Dynamics Simulation Study

Molecules ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 99 ◽  
Author(s):  
Siddharth Gautam ◽  
Tingting Liu ◽  
David Cole
Keyword(s):  
Molecular Dynamics ◽  
Monte Carlo ◽  
Time Scales ◽  
Rotational Motion ◽  
High Pressures ◽  
Sorption Isotherms ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Structure And Dynamics ◽  
Low Pressures

Silicalite is an important nanoporous material that finds applications in several industries, including gas separation and catalysis. While the sorption, structure, and dynamics of several molecules confined in the pores of silicalite have been reported, most of these studies have been restricted to low pressures. Here we report a comparative study of sorption, structure, and dynamics of CO2 and ethane in silicalite at high pressures (up to 100 bar) using a combination of Monte Carlo (MC) and molecular dynamics (MD) simulations. The behavior of the two fluids is studied in terms of the simulated sorption isotherms, the positional and orientational distribution of sorbed molecules in silicalite, and their translational diffusion, vibrational spectra, and rotational motion. Both CO2 and ethane are found to exhibit orientational ordering in silicalite pores; however, at high pressures, while CO2 prefers to reside in the channel intersections, ethane molecules reside mostly in the sinusoidal channels. While CO2 exhibits a higher self-diffusion coefficient than ethane at low pressures, at high pressures, it becomes slower than ethane. Both CO2 and ethane exhibit rotational motion at two time scales. At both time scales, the rotational motion of ethane is faster. The differences observed here in the behavior of CO2 and ethane in silicalite pores can be seen as a consequence of an interplay of the kinetic diameter of the two molecules and the quadrupole moment of CO2.

scholarly journals The thermal decomposition of acetaldehyde and the existence of different activated states

1933 ◽  
Vol 141 (843) ◽  
pp. 41-55 ◽  
Keyword(s):  
High Pressures ◽  
Initial Pressure ◽  
Bimolecular Reaction ◽  
Bimolecular Reactions ◽  
First Order ◽  
Straight Line ◽  
Gas Reactions ◽  
Pass Through ◽  
Low Pressures ◽  
Kinetics Of

Homogeneous thermal gas reactions were at one time tacitly assumed to possess a definite order, unimolecular and bimolecular reactions, for example, being sharply distinguished. The kinetics of the decomposition of acetalde­ hyde, CH 3 CHO = CH 4 + CO, over the pressure range of 100 to 400 mm. were found to satisfy the criterion of a bimolecular reaction, namely, that the reciprocal of the time for half change (1/ t 1/2 ) )plotted against the initial pressure ( p 0 ) gave a straight line inclined to the axes. The line, however, did not pass through the origin, as may be seen in fig. 1 of the present paper. This indicated the presence of some first order reaction, the nature of which was not determined. Subsequently, in accordance with the collision theory of activation and deactivation, it was shown that certain reactions, sometimes called quasiummolecular, change their order from the second at low pressures to the first at high pressures. This apparently was the reverse of the behaviour shown by acetaldehyde.

Effect of Heat Flux on Droplet Entrainment Using Annular Flow Dryout Model

2010 ◽  
Author(s):  
Masroor Ahmad ◽  
Evgeniy Burlutskiy ◽  
Simon P. Walker ◽  
Geoffrey F. Hewitt
Keyword(s):  
Experimental Data ◽  
Heat Flux ◽  
High Pressure ◽  
Liquid Film ◽  
Annular Flow ◽  
High Pressures ◽  
Droplet Entrainment ◽  
Annular Film ◽  
Low Pressures ◽  
Flow Experiments

Annular film dryout depends upon the competition of entrainment, deposition and evaporation processes between the droplet-laden core and wall liquid film. In this paper, effect of heat flux on droplet entrainment is analyzed by modeling different low and high pressure diabatic annular flow experiments numerically using an annular flow dryout model (AFM). Overall, the AFM predicted the experimental data reasonably accurately. It is concluded that at high pressures increasing heat flux may enhance net entrainment considerably but this effect diminishes at low pressures.

The catalytic oxidation of ethylene on palladium films

1962 ◽  
Vol 270 (1341) ◽  
pp. 219-231 ◽  
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
High Pressures ◽  
Kinetic Studies ◽  
Side Reaction ◽  
Reaction Scheme ◽  
Zero Order ◽  
Main Reaction ◽  
Rate Of Reaction ◽  
Low Pressures

The oxidation of ethylene has been studied on evaporated films of palladium in the temperature range 50 to 140 °C, and products were analyzed by means of a mass spectrometer. The main reaction was complete oxidation to carbon dioxide and water, but trace amounts of acetic anhydride and acetic acid were formed by a side reaction. Kinetic studies showed that the reaction was zero order with respect to the pressure of oxygen, first order in ethylene at low pressures but zero order at high pressures, and progressively poisoned by the two minor products. The activation energy associated with the initial rate of reaction was 14 kcal/mole. A number of subsidiary experiments were carried out including the oxidation of acetaldehyde at 77 °C which occurred rapidly producing acetic anhydride and some acetic acid. A reaction scheme was developed which accounted for the detailed kinetic behaviour of the oxidation of ethylene and possible mechanisms are discussed

scholarly journals The Effect of Temperature on the Chromatography of Insulin on Deae-Cellulose

1960 ◽  
Vol 13 (1) ◽  
pp. 69 ◽  
Author(s):  
IJ O'donnell ◽  
EOP Thompson
Keyword(s):  
Ionic Strength ◽  
Elution Curve ◽  
Deae Cellulose ◽  
Minor Component ◽  
Ammonia Removal ◽  
Effect Of Temperature ◽  
Bovine Plasma ◽  
Three Samples ◽  
Ph Range ◽  
A Minor

The effect of ionic strength (range 0,15-0, 3), pH (range 7-9), and temperature (range I-25�C) on the chromatographic behaviour of three samples of insulin on diethylaminoethyl (DEAE)-cellulose columns has been studied. These three factors have a similar effect, a decrease of temperature or pH and an increase in ionic strength lowering the elution volume of the protein. The marked effect of temperature is not due to aggregation-disaggregation of the insulin since bovine plasma albumin which does not aggregate reversibly also showed this effect. The desamido component of insulin could not be detected in commercial insulin under the conditions studied but a minor component varying from 2-6 per cent. of the insulin was separated, as well as various amounts of bound ammonia. Removal of zinc from the insulin did not affect the elution curve.

scholarly journals The influence of pressure on the spontaneous ignition of inflammable gas-air mixtures III—Hexane- and isobutane-air mixtures

1934 ◽  
Vol 146 (856) ◽  
pp. 113-129 ◽  
Keyword(s):  
Critical Pressure ◽  
High Pressures ◽  
Initial Pressure ◽  
Liquid Fuels ◽  
Spontaneous Ignition ◽  
Lower Range ◽  
Ignition Point ◽  
Wide Range ◽  
Temperature Ranges ◽  
Low Pressures

In two recent communications we described the results of investigations into the influence of varying initial pressure up to 15 atmospheres on the spontaneous ignition of butane- and pentane-air mixtures, showing that in each case the ignition were located in two distinct and widely separated temperature ranges, location in the higher range occurring at low pressures and in the lower range at high pressures. Transference of an ignition point from the higher to the lower range occurred sharply, at a critical pressure, which depended upon the hydrocarbon concerned and the composition of its mixture with air. The bearing of these observations upon the problem of knock was also discussed. A wide range of explosive media, comprising mainly the higher hydrocarbons contained in liquid fuels, is now being systematically studied, and the present paper summarizes the results obtained for hexane- and isobutane-air mixtures. So far, our results support the view (also recently endorsed by Neumann and Estrovitch) that the lower group of ignition points is the outcome of the survival and further rapid oxidation of certain intermediate bodies, a process favoured by high pressure. whereas the higher group results from ignitions mainly of the products of their thermal decompositions which are favoured by low pressure.

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