The Diffusivity of Methane Into Air Within Vertical Tubes

1990 ◽  
Vol 112 (4) ◽  
pp. 268-273
Author(s):  
R. Petela ◽  
G. A. Karim
Keyword(s):  
Constant Temperature ◽  
Vertical Cylinder ◽  
Effective Diffusivity ◽  
Concentration Changes ◽  
Temperature And Pressure ◽  
Vertical Tubes

An experimentally based effective diffusivity for methane is derived. Its application for predicting the concentration changes following the release of methane upwards into air at constant temperature and pressure within a vertical cylinder is then examined. Examples relating to the formation and dissipation of flammable mixtures following the release of methane into air are presented and discussed.

Accurate and efficient integration for molecular dynamics simulations at constant temperature and pressure

2013 ◽  
Vol 139 (16) ◽  
pp. 164106 ◽  
Author(s):  
Ross A. Lippert ◽  
Cristian Predescu ◽  
Douglas J. Ierardi ◽  
Kenneth M. Mackenzie ◽  
Michael P. Eastwood ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Constant Temperature ◽  
Efficient Integration ◽  
Temperature And Pressure ◽  
Dynamics Simulations

scholarly journals A 3-In-1 Approach to Evaluate Gas Hydrate Inhibitors

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2921
Author(s):  
Narendra Kumar ◽  
Niaz Bahar Chowdhury ◽  
Juan G. Beltran
Keyword(s):  
Constant Temperature ◽  
Gas Hydrates ◽  
Equilibrium Points ◽  
Hydrate Formation ◽  
Temperature Gradients ◽  
Fixed Temperature ◽  
Single Experiment ◽  
Temperature Growth ◽  
Temperature And Pressure ◽  
Methane Gas Hydrates

With a single apparatus and very short experimentation times, we have assessed phase equilibria, apparent kinetics and morphology of methane gas hydrates in the presence of thermodynamic inhibitors ethane-1,2-diol (MEG) and sodium chloride (NaCl); and kinetic hydrate inhibitor polyvinyl-pyrrolidone (PVP). Tight, local temperature control produced highly repeatable crystal morphologies in constant temperature systems and in systems subject to fixed temperature gradients. Hydrate-Liquid-Vapor (HLV) equilibrium points were obtained with minimal temperature and pressure uncertainties ( u T avg = 0 . 13 K and u p = 0 . 005 MPa). By applying a temperature gradient during hydrate formation, it was possible to study multiple subcoolings with a single experiment. Hydrate growth velocities were determined both under temperature gradients and under constant temperature growth. It was found that both NaCl and MEG act as kinetic inhibitors at the studied concentrations. Finally, insights on the mechanism of action of classical inhibitors are presented.

Electrical activity in mesenteric nerves after perfusion of gut lumen

1962 ◽  
Vol 202 (4) ◽  
pp. 725-730 ◽  
Author(s):  
K. N. Sharma ◽  
E. S. Nasset
Keyword(s):  
Amino Acids ◽  
Small Intestine ◽  
Amino Acid ◽  
Electrical Activity ◽  
Constant Temperature ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Temperature And Pressure

Impulses from the peripheral cut end of mesenteric nerves to the intestinal loops of anesthetized cats were recorded oscilloscopically. Dogs with Thiry-Vella loops and with electrodes implanted in mesenteric nerves were used for chronic studies. The loops were perfused with different solutions at constant temperature and pressure. After glucose perfusion of the lumen the increase in frequency of firing was more marked in medium and larger fibers. After perfusion with single amino acids the increase was more conspicuous in smaller fibers. Amigen (amino acid mixture, dextrose, and salts) perfusion resulted in mixed patterns. No appreciable changes were observed with 0.9% NaCl, Tyrode's solution, and 0.025 n NaOH, but a slight increase was obtained with 0.025 n HCl. The possibility of some chemoreceptor mechanism in the small intestine is suggested. Its possible role in ingestion of food is discussed.

scholarly journals Analysis of various polymer parts in contact with biodiesel

2021 ◽  
Vol 2 (2) ◽  
pp. 83
Author(s):  
Miguel Moreno ◽  
Alberto Calio ◽  
Nancy Quaranta ◽  
Adrian Cristobal
Keyword(s):  
Constant Temperature ◽  
Atmospheric Pressure ◽  
Industrial Process ◽  
Polymeric Materials ◽  
Wear Characteristics ◽  
Form Part ◽  
Time Periods ◽  
Temperature And Pressure ◽  
The One

<p>In this paper, several parts consisting of polymeric materials are studied, in order to determine if they are affected when they are kept in contact with biodiesel at constant temperature and pressure. The samples used are constituted by polymers of silicone (S), acrylonitrile (AN) and propylene hexafluor (Viton-V7). These materials have been selected for investigation because they form part of an industrial process in which they are used, and have been observed early wear characteristics thereof. They consist of seals and cords which are in contact with biodiesel. These materials were kept immersed in biodiesel at atmospheric pressure at a temperature of 40°C for time periods up to 120 days. Virgins tested ones are characterized by various techniques: OM, SEM, XRD, DTA-TGA, among others. Viton sample was the least affected by treatment, while the acrylonitrile sample is the one that has shown the greatest variations.</p>

Practical applications and Gibbs energy (G)

2020 ◽  
pp. 514-520
Author(s):  
Robert T. Hanlon
Keyword(s):  
Free Energy ◽  
Gibbs Energy ◽  
Gibbs Free Energy ◽  
Constant Temperature ◽  
Chemical Reaction ◽  
Maximum Amount ◽  
Practical Applications ◽  
Temperature And Pressure

Gibbs introduced a new property, later called Gibbs free energy (G), to provide the means by which to quantify the maximum amount of work that can be generated by a given process at constant temperature and pressure. This property can also be used to determine chemical reaction spontaneity.

The Application of Siemens PLC in Traditional Chinese Medicine Production

2011 ◽  
Vol 287-290 ◽  
pp. 3061-3064
Author(s):  
Tie Cheng Wang ◽  
Zhan Ping Du ◽  
Lei Liu ◽  
Hai Xia Bi
Keyword(s):  
Chinese Medicine ◽  
Traditional Chinese Medicine ◽  
Key Words ◽  
Constant Temperature ◽  
Constant Pressure ◽  
Recent Application ◽  
Controlling System ◽  
Temperature And Pressure

This article mainly introduces the design thought of Siemens PLC applying for the production of traditional Chinese medicine. In addition, the design and investigation on constant temperature and pressure of a new automatic traditional Chinese medicine dripping machine is introduced in this paper also. The automatic traditional Chinese medicine dripping machine is wholly controlled by the Siemens PLC. Recent application on spots shows: this PLC controlling system works reliably, operates conveniently. 【 Key words 】 traditional Chinese medicine; Siemens PLC; constant pressure; constant temperature

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