Densities of Amorphous Polymers at High Pressures

1976 ◽  
Vol 49 (2) ◽  
pp. 207-209
Author(s):  
S. Beret ◽  
J. M. Prausnitz
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Equation Of State ◽  
Rational Design ◽  
High Pressures ◽  
Amorphous Polymers ◽  
Low Pressure ◽  
Experimental Results ◽  
Tait Equation ◽  
Simple Method

Abstract Experimentally determined densities and compressibilities of amorphous polymers are frequently available; but, because of experimental difficulties, few experimental results have been reported at high pressures. Such densities, however, are sometimes required for rational design of extrusion and similar processes. We report here a simple method for estimating densities and compressibilities at high pressures from experimental compressibilities at low pressure. Our method is based on a relation for liquids suggested by Wada and developed by Chueh and Prausnitz. The purpose of this note is to suggest a method for estimating polymer densities at high pressure wherever experimental data are insufficient for obtaining parameters needed in an equation of state, as, for example, the Tait equation.

An Experimental Study on the Equation of State of Cementitious Materials Using Confined Compression Tests

2016 ◽  
Vol 711 ◽  
pp. 830-836 ◽  
Author(s):  
Yuri S. Karinski ◽  
Semion Zhutovsky ◽  
Vladimir R. Feldgun ◽  
David Z. Yankelevsky
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
High Pressure ◽  
Equation Of State ◽  
High Pressures ◽  
Uniaxial Loading ◽  
Ductile Material ◽  
Compression Tests ◽  
Confined Compression ◽  
Very High

The behavior of concrete under severe loading is of interest, especially for problems like ballistic impact and penetration and near distance explosions, where very high pressures are developed. For these problems the behavior of concrete at very high hydrostatic pressures is of importance. There is very little data available on concrete behavior at that high pressure level. Therefore there is much need for an extensive experimental work in order to provide necessary data and illuminate the rather obscure area of concrete behavior at high pressures. However high pressure controlled testing requires special and expensive equipment, and the testing is associated with a wide variety of technical problems. Recently published experimental data, obtained by utilizing a high-capacity tri-axial press, indicates that concrete that is subjected to high pressures behaves differently than concrete under low uniaxial loading. When uniaxial loading is applied, without any confining pressure, the concrete specimen demonstrates a well-known brittle behavior where failure is caused by a localized damage. Quite to the contrary, at high levels of confining pressures, the concrete behaves like a ductile material, and its failure is associated with diffuse material damage. The experimental data at the very high pressure range is most important to understand the processes of damage evolution that governs the characteristics of the equation of state. This paper presents the development of an experimental setup that is capable of performing confined compression tests of mortar and concrete specimens at high pressures up to 400MPa. The experimental study aims at investigating the effect of water/cement ratio as well as the ratio of fine aggregate on the different branches of the equation of state: active loading and unloading/reloading. The paper presents some of the test results as well as a new equation of state that is based on the multi scale approach. The model is applicable for dry materials; cementitious paste and concrete in which the pores are filled with water should be treated differently to account for the liquid phase.

scholarly journals Crystal and electronic structure engineering of tin monoxide by external pressure

2021 ◽  
Author(s):  
Kun Li ◽  
Junjie Wang ◽  
Vladislav A. Blatov ◽  
Yutong Gong ◽  
Naoto Umezawa ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Band Gap ◽  
High Pressures ◽  
Low Pressure ◽  
Widespread Application ◽  
Space Group ◽  
Tin Monoxide ◽  
High Possibility ◽  
Pressure Phase

AbstractAlthough tin monoxide (SnO) is an interesting compound due to its p-type conductivity, a widespread application of SnO has been limited by its narrow band gap of 0.7 eV. In this work, we theoretically investigate the structural and electronic properties of several SnO phases under high pressures through employing van der Waals (vdW) functionals. Our calculations reveal that a metastable SnO (β-SnO), which possesses space group P21/c and a wide band gap of 1.9 eV, is more stable than α-SnO at pressures higher than 80 GPa. Moreover, a stable (space group P2/c) and a metastable (space group Pnma) phases of SnO appear at pressures higher than 120 GPa. Energy and topological analyses show that P2/c-SnO has a high possibility to directly transform to β-SnO at around 120 GPa. Our work also reveals that β-SnO is a necessary intermediate state between high-pressure phase Pnma-SnO and low-pressure phase α-SnO for the phase transition path Pnma-SnO →β-SnO → α-SnO. Two phase transition analyses indicate that there is a high possibility to synthesize β-SnO under high-pressure conditions and have it remain stable under normal pressure. Finally, our study reveals that the conductive property of β-SnO can be engineered in a low-pressure range (0–9 GPa) through a semiconductor-to-metal transition, while maintaining transparency in the visible light range.

scholarly journals Equation of state for rhodium at high pressures

2021 ◽  
Vol 2057 (1) ◽  
pp. 012118
Author(s):  
K V Khishchenko
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Equation Of State ◽  
Internal Energy ◽  
Specific Volume ◽  
High Pressures ◽  
Thermodynamic Characteristics ◽  
Wide Range ◽  
Hydrodynamic Processes

Abstract An equation of state has been developed for rhodium in a wide range of changes in the specific volume and internal energy. The results of calculations of the thermodynamic characteristics of this metal are presented in comparison with the available experimental data at high pressures. This equation of state can be used in the numerical simulation of hydrodynamic processes under intense impulse influences on matter.

A High Pressure Clearance Seal

1968 ◽  
Vol 90 (2) ◽  
pp. 412-416 ◽  
Author(s):  
M. M. Kamal
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Simple Method ◽  
Elastic Deformations ◽  
Metal Seal

A simple method for estimating leakage and friction losses for a high-pressure sleeve type low-clearance metal seal is presented. Elastic deformations in the shaft and seal and the change in viscosity due to the high pressures are accounted for and found to be of major importance.

Some Numerical Simulations and an Experimental Investigation of a Finger Seal

2005 ◽  
Author(s):  
Minel J. Braun ◽  
Hazel M. Pierson ◽  
Hongmin Li
Keyword(s):  
Experimental Investigation ◽  
High Pressure ◽  
Pressure Drop ◽  
Numerical Simulations ◽  
Mechanical Performance ◽  
Low Pressure ◽  
Pressure Differential ◽  
Experimental Results ◽  
Axial Pressure ◽  
Brush Seals

Finger seals (FS) are compliant seal configurations. Unlike brush seals, they exhibit hydrodynamic lifting capabilities which allow non-contact sealing between stationary and rotating members. The compliance combined with the non-contacting feature allows both axial and radial adjustment of the seal to the rotor excursions without endangering the integrity of the former. The embodiment of a two-layer finger seal with high pressure (1c) and low pressure (1b) laminates is shown in Figure1. In this paper we shall analyze the thermo-hydraulic and mechanical performance (axial and radial deformations and displacements) of a representative repetitive cell that contains four high pressure and four low-pressure fingers arranged axially in a staggered configuration, and subject to rotation and an axial pressure drop. We shall also present experimental results pertaining to the seal deformation under axial pressure differential and rotation.

Collision–induced absorption in gaseous methane at low temperatures

1986 ◽  
Vol 64 (7) ◽  
pp. 763-767 ◽  
Author(s):  
I. R. Dagg ◽  
A. Anderson ◽  
S. Yan ◽  
W. Smith ◽  
C. G. Joslin ◽  
...  
Keyword(s):  
Experimental Data ◽  
Low Temperatures ◽  
Low Frequency ◽  
Frequency Region ◽  
Experimental Results ◽  
Published Data ◽  
Frequency Range ◽  
Simple Method ◽  
Induced Absorption ◽  
Good Agreement

A recently developed theory for collision-induced absorption in methane is compared with experimental results over a wider spectral range and at lower temperatures than previously reported. The present experimental results covering the frequency range below 400 cm−1 exhibit good agreement with other recently published data. The theory shows excellent agreement with experiment in the low-frequency region below approximately 200 cm−1 but underestimates the experimental data somewhat at higher frequencies. Possible theoretical reasons for this discrepancy are given. The theory represents a simple method of obtaining a good estimate of the collision-induced absorption spectra of methane in this frequency region and for extrapolating to lower temperatures for which experimentation is not feasible. In addition, the moments α1 and γ1are compared with earlier determinations and indicate good agreement with the previously obtained values for the octupole and hexadecapole moments of methane.

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.

Simulation of Structural Parameters and Superconducting Transition Temperature of MgB2 under Pressure

2005 ◽  
Vol 475-479 ◽  
pp. 3319-3322
Author(s):  
Yang Shao ◽  
X. Zhang ◽  
Fu Ling Tang
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Pressure Effect ◽  
Structural Parameters ◽  
Experimental Results ◽  
Bcs Theory ◽  
Superconducting Transition ◽  
Potential Parameters

We successfully developed the potential parameters for simulation of MgB2. With these potential parameters, we calculate the lattice parameters and volume variations with pressure up to 240GPa. All these results agree well with experimental data under 40GPa and provide reasonable tendencies from 40GPa to 240GPa. By employing the McMillan expression, it is found that the lattice stiffening dominants the behavior of Tc under pressure in the scope of BCS theory. Using our calculated Grüneisen parameter G g , the simulated pressure effect on Tc accords well with experimental results. Our result shows that the Tc of MgB2 can be destroyed by high pressure.

Mixing rules for the back equation of state

1987 ◽  
Vol 52 (1) ◽  
pp. 29-44 ◽  
Author(s):  
Tomáš Boublík ◽  
Benjamin C.-Y. Lu
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Equation Of State ◽  
Van Der Waals ◽  
Energy Parameter ◽  
Excess Properties ◽  
Mixing Rules ◽  
Good Prediction ◽  
Mixing Rule ◽  
Simple Molecules

Van der Waals type of mixing rule for the energy parameter us together with the mixing rules introduced previously for parameters αs and Vs0 of the BACK equation were employed in evaluating excess properties of mixing, Henry's law constant and high pressure vapour-liquid equilibria. A comparison with the experimental data reveals that the BACK equation together with the suggested mixing rules could provide good prediction of equilibrium properties of mixtures of relatively simple molecules.

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