scholarly journals AN INVESTIGATION OF THE DENSITY OF A VAPOR IN EQUILIBRIUM WITH A LIQUID NEAR THE CRITICAL TEMPERATURE

1933 ◽  
Vol 9 (3) ◽  
pp. 217-239 ◽  
Author(s):  
J. S. Tapp ◽  
E. W. R. Steacie ◽  
O. Maass
Keyword(s):  
Critical Temperature ◽  
Critical Phenomena ◽  
Gaseous Phase ◽  
Reaction Rates ◽  
Short Time ◽  
Work Done ◽  
Outstanding Work ◽  
Considerable Doubt ◽  
Good Agreement ◽  
Made In

An account is given of the outstanding work done and theories developed in connection with the critical phenomena during the last century. It was because of certain observations made in this laboratory a short time ago upon reaction rates at the critical temperature that the present investigation was begun with a view to providing more definite data concerning the density of both the liquid and gas in the region of the critical point.Experimental conditions have been kept under the most rigid supervision and previous errors eliminated or evaluated. A distinctly new technique has been developed, utilizing quartz spirals, for determining the density of both the liquid and gaseous phase almost simultaneously, up to, and past, the point where the meniscus vanishes. The results have been compiled from a great many observations taken over a period of two years upon eight separate units. In general, good agreement has been obtained in all but one case, and a probable solution has been advanced for the exception. Primarily, the paper is an experimental one designed to fill an important gap in previously recorded data.Extensive theoretical deductions have been purposely omitted because of the radical nature of the findings; and it would be necessary to proceed further with the work before anything really definite might be concluded. Briefly, it might be stated that the results cast considerable doubt upon Van der Waals' classical theory of the continuity of state.

scholarly journals Results from Swedish oblique soundings campaigns

1994 ◽  
Vol 37 (2) ◽  
Author(s):  
M. Broms ◽  
B. Lundhorg
Keyword(s):  
Time Scales ◽  
The Other ◽  
Southern Spain ◽  
The Cost ◽  
Short Time ◽  
Good Agreement ◽  
Made In

In the context of the COST 238, PRIME project, two campaigns of oblique soundings with the Chirpsounder receiver at Linkoping, Sweden were made in parallel with vertical sounding campaigns. One campaign was made in June, 1992, when transmissions from Southern Spain were monitored, the other in December, 1992 when a transmitter at Chelveston, U.K, was monitored. The scaled values of F2MOF, 2-hop F2MOF and LOF give information on the variation of these parameters on short time scales and from day to day. High correlations between 2-hop F2MOF and F2MOF are found. Good agreement was found between the 2-hop MOF and MUF(1400)F2 calculated from vertical soundings at St. Peter Ording, Germany.

scholarly journals Synthesis of Metal Organic Frameworks by Ball-Milling

Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 15
Author(s):  
Cheng-An Tao ◽  
Jian-Fang Wang
Keyword(s):  
Ball Milling ◽  
Large Scale ◽  
Raw Materials ◽  
Metal Organic Frameworks ◽  
Research Topic ◽  
Mass Ratio ◽  
Time Consumption ◽  
Metal Organic ◽  
Short Time ◽  
Made In

Metal-organic frameworks (MOFs) have been used in adsorption, separation, catalysis, sensing, photo/electro/magnetics, and biomedical fields because of their unique periodic pore structure and excellent properties and have become a hot research topic in recent years. Ball milling is a method of small pollution, short time-consumption, and large-scale synthesis of MOFs. In recent years, many important advances have been made. In this paper, the influencing factors of MOFs synthesized by grinding were reviewed systematically from four aspects: auxiliary additives, metal sources, organic linkers, and reaction specific conditions (such as frequency, reaction time, and mass ratio of ball and raw materials). The prospect for the future development of the synthesis of MOFs by grinding was proposed.

scholarly journals Sonochemical and Sonoelectrochemical Production of Energy Materials

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 284
Author(s):  
Faranak Foroughi ◽  
Jacob J. Lamb ◽  
Odne S. Burheim ◽  
Bruno G. Pollet
Keyword(s):  
Reaction Rates ◽  
Surface Cleaning ◽  
Energy Materials ◽  
Fast Reaction ◽  
Ultrasound Frequency ◽  
Production Of Hydrogen ◽  
Scientists And Engineers ◽  
Electrocatalyst Materials ◽  
Made In ◽  
Semiconductor Photocatalyst

Sonoelectrochemistry is the combination of ultrasound and electrochemistry which provides many advantages in electrochemistry, such as fast reaction rates, surface cleaning and activation, and increased mass transport at an electrode. Due to the advantages, some efforts have been made in order to benefit sonoelectrochemistry in the field of energy and environmental engineering. This review paper highlights the developed progress of the application of sonoelectrochemistry in the production of hydrogen, electrocatalyst materials and electrodes for fuel cells and semiconductor photocatalyst materials. This review also provides the experimental methods that are utilized in several sonoelectrochemical techniques, such as different set-ups generally used for the synthesis of energy-related materials. Different key parameters in the operation of sonoelectrochemical synthesis including ultrasonication time, ultrasound frequency and operation current have been also discussed. There are not many research articles on the sonoelectrochemical production of materials for supercapacitors and water electrolyzers which play crucial roles in the renewable energy industry. Therefore, at the end of this review, some articles which have reported the use of ultrasound for the production of electrocatalysts for supercapacitors and electrolyzers have been reviewed. The current review might be helpful for scientists and engineers who are interested in and working on sonoelectrochemistry and electrocatalyst synthesis for energy storage and energy conversion.

scholarly journals An approach to the modeling of a virtual thermal manikin

2014 ◽  
Vol 18 (4) ◽  
pp. 1413-1423 ◽  
Author(s):  
Dragan Ruzic ◽  
Sinisa Bikic
Keyword(s):  
Turbulence Models ◽  
Thermal Conditions ◽  
Heat Fluxes ◽  
Thermal Manikin ◽  
Flow Conditions ◽  
Body Segments ◽  
Nominal Size ◽  
Natural Flow ◽  
Good Agreement ◽  
Made In

The aim of the research described in this paper, is to make a virtual thermal manikin that would be simple, but also robust and reliable. The virtual thermal manikin was made in order to investigate thermal conditions inside vehicle cabins. The main parameters of the presented numerical model that were investigated in this paper are mesh characteristics and turbulence models. Heat fluxes on the manikin's body segments obtained from the simulations were compared with published results, from three different experiments done on physical thermal manikins. The presented virtual thermal manikin, meshed with surface elements of 0.035 m in nominal size (around 13,600 surface elements) and in conjunction with the two-layer RANS Realizable k-? turbulence model, had generally good agreement with experimental data in both forced and natural flow conditions.

Technically Classified Rubber—The Non-Rubber Content and the Measurement of Cure Rate

1953 ◽  
Vol 26 (3) ◽  
pp. 655-673 ◽  
Author(s):  
A. G. Veith
Keyword(s):  
Preliminary Investigation ◽  
National Bureau ◽  
Cure Rate ◽  
Average Value ◽  
Astm Method ◽  
Viscosity Increase ◽  
Strain Testing ◽  
Time Test ◽  
Short Time ◽  
Good Agreement

Abstract The nonrubber content of typical samples of all grades of technically classified rubber has been determined. It is found that the nonrubber content increases in the order: red, yellow, and blue. The chemical analyses performed to determine the nonrubber content were as follows: per cent ash, per cent nitrogen, per cent acetone extract, and per cent fatty acid. The pH of both a slurry of the ash and the aqueous digest indicates that blue rubber is more basic in these respects than are red and yellow rubbers. The measurement of the cure rate of these samples of technically classified rubber has been carried out by means of (1) conventional stress-strain testing, (2) the present ASTM method utilizing the Mooney viscometer, (3) the National Bureau of Standards strain test, (4) a new and more quantitative approach developed by Gee and coworkers, and (5) a utilization of the Mooney viscometer to determine two of the parameters of Gee's equation which gives the time dependence of modulus. All of these methods place the rubbers in the same relative order. The use of the viscometer to determine two of the parameters of Gee's equation was prompted by the degree of correlation between the rate parameter obtained with the present ASTM method and the rate constant k calculated by Gee's methods. As a result of a preliminary investigation as to the causes of viscosity increases at curing temperatures, it was found that, within limits of experimental error, all of the viscosity increase is due to the formation of a cross-linked network, with a linear relationship existing between viscosity increase ΔVc and modulus (at 100 per cent elongation) f. The results of a comparison of the rate constants obtained by the viscometer and by Gee's method indicate that for MBT mixes at 260° F there is good agreement between the methods. Statistical analysis shows that the samples employed for this study are significantly different in their rate of cure. The variance, range, and mean of some of the parameters obtained with the viscometer over a 10-week period are also given. It is suggested that the Mooney viscometer be employed to classify natural rubber according to its cure rate. If this is done, it will be necessary to define the degree of accuracy desired. To determine accurately the cure rate, it is necessary that the viscometer be used in conjunction with a press cure for the estimation of the parameter f∞. If it is not feasible to carry out press cures, an average value for f∞ can be assumed, and then only a short time test with the viscometer is required.

scholarly journals Post-liquefaction reconsolidation of sand

2016 ◽  
Vol 472 (2186) ◽  
pp. 20150745 ◽  
Author(s):  
O. Adamidis ◽  
G. S. P. Madabhushi
Keyword(s):  
Void Ratio ◽  
One Dimensional ◽  
Geotechnical Centrifuge ◽  
Significant Damage ◽  
Pore Water Pressures ◽  
The One ◽  
Crucial Parameter ◽  
Excess Pore ◽  
Good Agreement ◽  
Made In

Loosely packed sand that is saturated with water can liquefy during an earthquake, potentially causing significant damage. Once the shaking is over, the excess pore water pressures that developed during the earthquake gradually dissipate, while the surface of the soil settles, in a process called post-liquefaction reconsolidation. When examining reconsolidation, the soil is typically divided in liquefied and solidified parts, which are modelled separately. The aim of this paper is to show that this fragmentation is not necessary. By assuming that the hydraulic conductivity and the one-dimensional stiffness of liquefied sand have real, positive values, the equation of consolidation can be numerically solved throughout a reconsolidating layer. Predictions made in this manner show good agreement with geotechnical centrifuge experiments. It is shown that the variation of one-dimensional stiffness with effective stress and void ratio is the most crucial parameter in accurately capturing reconsolidation.

A Simple Statistical Theory for Grain Growth in Materials.

1990 ◽  
Vol 209 ◽  
Author(s):  
P. Mulheran ◽  
J.H. Harding
Keyword(s):  
Growth Rate ◽  
Monte Carlo ◽  
Statistical Theory ◽  
Stochastic Model ◽  
Grain Growth ◽  
Three Dimensional ◽  
Monte Carlo Procedure ◽  
Short Time ◽  
2D And 3D ◽  
Good Agreement

A Monte Carlo procedure has been used to study the ordering of both two and three dimensional (2d and 3d) Potts Hamiltonians, further to the work of Anderson et al. For the 3d lattice, the short time growth rate is found to be much slower than previously reported, though the simulated microstructure is in agreement with the earlier studies. We propose a new stochastic model that gives good agreement with the simulations.

An analytical model of an I-cored coil located above a conductive material with a hole

2018 ◽  
Vol 82 (2) ◽  
pp. 21001
Author(s):  
Grzegorz Tytko ◽  
Leszek Dziczkowski
Keyword(s):  
Test Object ◽  
Middle Layer ◽  
Axially Symmetric ◽  
The Finite Element Method ◽  
Cylindrical Coordinate ◽  
Air Space ◽  
Through Hole ◽  
Tree Method ◽  
Good Agreement ◽  
Made In

The paper examines the problem of an axially symmetric I-cored coil located above a three-layered plate with a hole in the middle layer. A cylindrical coordinate system was applied, wherein the solution domain was truncated in the radial direction. The employment of the truncated region eigenfunction expansion (TREE) method resulted in deriving the final formulas for the change of the coil impedance with regard to the air space, and also pertaining to the test object without a flaw. Formulas for various configurations of the test object, among others for a surface hole, a subsurface hole and a through hole, have been presented. For the purpose of defectoscopy, the influence of the hole in the plate on the impedance components was investigated. The calculations were made in Matlab for frequencies from 100 Hz to 50 kHz. The obtained results were verified using the finite element method (FEM) in Comsol Multiphysics package. A very good agreement was observed in the case of both the resistance and reactance.

scholarly journals ACTUALITY OF APPLICATION OF BIOGAS INSTALLATIONS IN RUSSIA AND ABROAD

2017 ◽  
Vol 12 (2) ◽  
pp. 71-74
Author(s):  
Булат Зиганшин ◽  
Bulat Ziganshin ◽  
Ильназ Кашапов ◽  
Ilnaz Kashapov ◽  
Ильнур Гайфуллин ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Power Plants ◽  
Biogas Production ◽  
Operating Experience ◽  
Farm Animals ◽  
National Program ◽  
Urban Wastewater ◽  
The World ◽  
Short Time ◽  
Made In

The first scientific developments in the field of biogas technologies were made in Russia more than 70 years ago. Since the 50th years one of the main directions was the anaerobic processing of activated sludge and sediments of urban wastewater. This method attracted attention in connection with the idea of obtaining biogas mainly from the manure of farm animals. Thanks to this in the middle of 50th years a number of pilot plants for biogas production were built in Zaporozhia, Belorussian, Georgian, Moldavian branches of All-Russian Institute of Agriculture Electrification, and also in Ekaterinburg. However, the operating experience of these installations was insignificant - one - two seasons. The problem of obtaining and using biogas is given great attention abroad. In a short time, in many countries around the world a whole industry for the production of biogas has emerged. The leader in the development of biogas industry is China. Since the middle of 1970, the National Program for the production of biogas from livestock wastes has been operating in this country. Currently, there are 10 million farm bioreactors. In addition, 40 000 biogas stations, 24 000 biogas treatment plants operate in China, which provides operation of 190 power plants.

scholarly journals In-Depth Verification of a Numerical Model for an Axisymmetric RC Dome

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2152
Author(s):  
Przemysław Czumaj ◽  
Sławomir Dudziak ◽  
Zbigniew Kacprzyk
Keyword(s):  
Three Dimensional ◽  
Spatial Models ◽  
Detailed Comparison ◽  
The Finite Element Method ◽  
Robot System ◽  
Engineering Structures ◽  
Computational Analyses ◽  
Computational Systems ◽  
Good Agreement ◽  
Made In

The designers of civil engineering structures often have to face the problem of the reliability of complex computational analyses performed most often with the Finite Element Method (FEM). Any assessment of reliability of such analyses is difficult and can only be approximate. The present paper puts forward a new method of verification and validation of the structural analyses upon an illustrative example of a dome strengthened by circumferential ribs along the upper and lower edges. Four computational systems were used, namely Abaqus, Autodesk Robot, Dlubal RFEM, and FEAS. Different models were also analyzed—two-dimensional (2D) and three-dimensional (3D) ones using continuum, bar, and shell finite elements. The results of the static (with two kinds of load—self-weight and load distributed along the upper ring) and modal analyses are presented. A detailed comparison between the systems’ and models’ predictions was made. In general, the spatial models predicted a less stiff behavior of the analyzed dome than the planar models. The good agreement between different models and systems was obtained for the first natural frequency with axisymmetric eigenmodes (except from the Autodesk Robot system). The presented approach to the verification of complex shell–bar models can be effectively applied by structural designers.

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