scholarly journals General considerations on the theory of the separation of H 1 and H 2 by electrolysis of water

1934 ◽  
Vol 144 (852) ◽  
pp. 452-466 ◽  
Keyword(s):  
A Priori ◽  
Point Of View ◽  
Theoretical Point ◽  
High Current ◽  
Hydrogen Electrode ◽  
Effective Separation ◽  
A Value ◽  
Rates Of Evolution ◽  
Wide Range ◽  
Current Densities

1. The Facts .―In a solution of NaOH (or KOH) with nickel (perhaps with other) electrodes and at high current densities of the order of 1 ampere per cm. 2 of electrode the observed rates of evolution E 1 and E 2 of H 1 and H 2 at the cathode obey an equation of the type E 1 /E 2 = q D 1 /D 2 , (1) where D 1 and D 2 are the relative concentraction of the H 1 and H 2 atoms in the water as a whole. The coefficient q has been shown to be independent of D 1 /D 2 over a very wide range of relative concentrations. Under the conditions most favourable to separation, which appear to be those just specified, q can have a value as great as 6, or perhaps 7. With other metals than nickel for the electrodes and with lower current densities the factor q may fall to a value well below 2 or even to a value so nearly unity that no effective separation occurs. The dependence of q (if any) on the temperature of the solution is not known. 1.1. The Arguments .―The facts have already been commented on by Polanyi from the theoretical point of view. He has been led to conclude from them that the separation is to be attributed to a difference of " over potential" for the deposition of H 1 and H 2 ions on the cathode, and consequently that Gurney's theory of the over-potential of the hydrogen-electrode at low current densities (as measured, for example, by Bowden) must be discarded. These conclusions if correct and unavoidable are of the greatest importance. It is most general way possible, in order to see that no types of mechanism have been overlooked which could lead to the observed results. When this is done it is found that the mechanism discussed by Polanyi which refers the separation to differences of over-potential is not the only mechanism which must be held possible a priori . The observed separation could perfectly well occur by a mechanism consistent with Gurney's theory. It does not yet appear to be possible to decide confidently between the two possibilities on experimental grounds.

The Control of the Eye's Intrinsic Muscles: A Multivariable Optimum Performance Control System

1968 ◽  
Vol 1 (8) ◽  
pp. T.129-T.132 ◽  
Author(s):  
F. M. Toates
Keyword(s):  
Control System ◽  
Control Systems ◽  
Pupil Diameter ◽  
Control Model ◽  
Point Of View ◽  
Theoretical Point ◽  
Pupil Control ◽  
Performance Control ◽  
A Value ◽  
Intrinsic Muscles

The reciprocal interaction between the accommodation and pupil control systems of the human eye is examined from a theoretical point of view. The system, which is responsible for maintaining pupil diameter at a value which is a compromise between conflicting requirements, is represented by a control model, and is considered in terms of the concept of a performance index.

CONCEPTUAL DIRECTIONS OF THE TAXATION THEORIES DEVELOPMENT THROUGH THE REALIZING PRISM INTERESTS OF THE STATE AND TAXPAYERS

2021 ◽  
Vol 7 (1) ◽  
pp. 188-204
Author(s):  
Yulia G. TYURINA ◽  
Kristina A. BANNOVA
Keyword(s):  
Income Tax ◽  
The State ◽  
Personal Income ◽  
Point Of View ◽  
Theoretical Point ◽  
Personal Income Tax ◽  
State Budget ◽  
Theoretical Understanding ◽  
Direct Taxation ◽  
Wide Range

Nowadays, direct taxation of personal income is used in almost all countries of the world, and to this day there are various changes that shift the share of revenue from these taxes towards increasing the state budget. The significance of the personal income tax in economic policy is also due to the fact that it affects the interests of almost the entire population of the country. A variety of disputes constantly arise around the personal income tax, which can be explained by a wide range of taxpayers in various social strata. The ongoing transformations in the tax area predetermine the construction of the individuals taxation fair system as the fulfillment of one of the conditions for improving the living standards of the population. The relevance of the study lies in the need to reform the tax system in Russia, namely, the taxation of personal income, in order to implement the principle of social justice, as well as to satisfy the fiscal component of this tax, respectively, to fulfill the interests of participants in tax relations. The purpose of the article is a theoretical understanding of the conceptual directions of the taxation theories development through the prism of realizing the interests of the state and taxpayers in the taxation system of personal income. The subject of this research is the set of economic relations between the state and individuals, formed in the process of taxation of personal income in Russia. The methodological basis was the conceptual provisions of the theories of taxation, scientific methods and methods of analysis. The scientific novelty of the work lies in the fact that the results of the methodological analysis of the taxation theories development through the prism of realizing the state interests and taxpayers will make it possible to solve from a theoretical point of view the issue of interests balance achieving of all parties, which will contribute to the development of practical measures to achieve a decent standard of living for the population.

scholarly journals Photoluminescence of Anodic Oxide Films on Aluminium

1976 ◽  
Vol 3 (2) ◽  
pp. 91-95 ◽  
Author(s):  
Sakae Tajima ◽  
Nobuyoshi Baba ◽  
Kenichi Shimizu ◽  
Issei Mizuki
Keyword(s):  
Electrolyte Concentration ◽  
Oxide Films ◽  
Anodic Oxide ◽  
Point Of View ◽  
High Current ◽  
Anodic Oxide Films ◽  
Inorganic Acids ◽  
Purity Aluminium ◽  
High Purity Aluminium ◽  
Current Densities

A wide variety of anodic oxide films were investigated from the photoluminescent point of view. It was found that the phenomenon of photoluminescence appears only on the films anodically formed in organic acids instead of inorganic acids. In particular, thick oxalic acid films formed in low electrolyte concentration, with high current densities on high purity aluminium, gave intense photoluminescence. The luminescent centres were presumed to be the carboxylate ions which had been incorporated in the films during anodisation.

Study of the properties of materials under complicated conditions of low cycle deformation

2021 ◽  
Vol 87 (7) ◽  
pp. 49-58
Author(s):  
N. A. Makhutov ◽  
М. M. Gadenin ◽  
О. F. Cherniavsky ◽  
A. О. Cherniavsky
Keyword(s):  
Initial Data ◽  
Equations Of State ◽  
Complex Loading ◽  
Time Factors ◽  
Point Of View ◽  
Theoretical Point ◽  
Operational Parameters ◽  
Practical Applications ◽  
Wide Range ◽  
Deformation Diagrams

Operational integrity of structures under complex combined modes of a loading depends on a significant number of combinations of operational parameters of thermomechanical impacts in part of loads, temperatures, duration, number of cycles, and deformation rates. The main laws governing the deformation of structural materials under complex loading are determined in conditions of combined standard, unified and special tests in laboratories. Using representative substantiations of physical and mechanical models for deformation diagrams in a wide range of loading conditions, taking into account the different scales of models, the structure of materials and the responsibility of structures, a stepwise consideration of the corresponding types of deformation is proposed: elastic, sign-variable flow, progressing accumulation of strains and their combination. At the same time, calculations of the structures can be carried out in the form of a hierarchical system in which each next level specifies the boundaries of permissible impacts towards expansion of the range of acting loadings, temperatures, rates and modes of deformation, which entails an increase in the bulk of the required initial data and complicates the calculations. The proposed methods of schematization of the physicomechanical properties and types of the equations of state for description of the deformation curves take into account the requirements of compactness of the initial data and the need of using both standard and unified methods for determining the characteristics of cyclic inelastic deformation and special methods as well. To describe the kinetics of deformation diagrams under aforementioned conditions both from the theoretical point of view and from the point of view of practical applications, power equations appeared most suitable; to reflect the role of the temperature factor exponential dependences should be used; whereas power dependences are useful to take into account time factors, strain rate, and conditions of two-frequency loading. The refined calculations at the higher and more complicated steps of the considered hierarchy providing the maximum possible use of the deformation and strength reserves of the materials and structures are to be based on the kinetic laws describing processes of low cycle deformation under complex modes of loading.

Le concept d'intégration en écologie appliquée

1972 ◽  
Vol 50 (3) ◽  
pp. 533-541 ◽  
Author(s):  
Gilbert Long
Keyword(s):  
Multidisciplinary Approach ◽  
Historical Data ◽  
A Priori ◽  
Point Of View ◽  
Trial And Error ◽  
A Posteriori ◽  
Horizontal Integration ◽  
Australian School ◽  
Wide Range ◽  
The One

The concept of integration has a wide range of meanings. The author first tries to bring out the point of view of specialists in natural resources. Two approaches are described: on the one hand that proceeding from elementary disciplines or from the nature of variables and on the other hand the ecosystematic or global, multidisciplinary approach. In the first one, integration is made a posteriori by trial and error. More important developments are devoted to the second approach; integration is said to be holistic and proceeds from a priori hypotheses (geomorphological postulate of the Australian school or phytoecological postulate of the Centre d'Etudes Phytosociologiques et Ecologiques Louis Emberger de Montpellier) and a posteriori interpretations. The phyto-ecological approach is especially well developed (vertical vs. horizontal integration). Verified integration is that which proceeds from mathematical models, from historical data, or experimentation.Total integration takes into account contributions from "naturalists" as well as from "humanists."

Development of Turbulence by the Interaction of Gas Flow with Plasmas

1973 ◽  
Vol 28 (8) ◽  
pp. 1281-1289 ◽  
Author(s):  
Lutz Niemeyer ◽  
Klaus Ragaller
Keyword(s):  
Gas Flow ◽  
Light Emission ◽  
Supersonic Nozzle ◽  
Physical Nature ◽  
Point Of View ◽  
Theoretical Point ◽  
High Current ◽  
Axial Pressure ◽  
Plasma Properties ◽  
Axial Pressure Gradient

A high current electric arc in the axis of a supersonic nozzle flow is studied experimentally and theoretically in order to clarify the physical nature of light emission fluctuations which are observed inside the nozzle. The gas flow is produced by discharging a high pressure reservoir of 20 at N2 through a nozzle of 12 mm throat diameter. The arc is fed with a rectangular current pulse of 1.9 kA amplitude and 5 ms duration. The light emission fluctuations of the arc are observed by photographic and photoelectric methods. The results of the observations are compared to theoretical estimates and lead to the conclusion that the fluctuations are caused by hydrodynamic turbulence. This turbulence is shown to be generated by the combined occurrence of a strong axial pressure gradient and a strong radial density gradient in the boundary layer between the arc and the surrounding cold gas flow. The influence of specific plasma properties on the character of the turbulence is briefly discussed from a theoretical point of view.

scholarly journals Approximation methods in modified gravity models

2018 ◽  
Vol 27 (15) ◽  
pp. 1848004 ◽  
Author(s):  
Baojiu Li
Keyword(s):  
Modified Gravity ◽  
Large Scale ◽  
A Priori ◽  
Point Of View ◽  
Cosmic Acceleration ◽  
Gravity Models ◽  
Approximation Methods ◽  
Theoretical Point ◽  
Speed Up ◽  
Efficiency And Reliability

We review some of the commonly used approximation methods to predict large-scale structure formation in modified gravity (MG) models for the cosmic acceleration. These methods are developed to speed up the often slow [Formula: see text]-body simulations in these models, or directly make approximate predictions of relevant physical quantities. In both cases, they are orders of magnitude more efficient than full simulations, making it possible to explore and delineate the large cosmological parameter space. On the other hand, there is a wide variation of their accuracies and ranges of validity, and these are usually not known a priori and must be validated against simulations. Therefore, a combination of full simulations and approximation methods will offer both efficiency and reliability. The approximation methods are also important from a theoretical point of view, since they can often offer useful insight into the nonlinear physics in MG models and inspire new algorithms for simulations.

STUDIES ON THE ELECTRO-OXIDATION OF TETRAVALENT URANIUM

1948 ◽  
Vol 26b (5) ◽  
pp. 441-455
Author(s):  
R. H. Betts
Keyword(s):  
Aqueous Solution ◽  
Uranyl Ion ◽  
Ion Concentration ◽  
Anode Potential ◽  
High Current ◽  
Tetravalent Uranium ◽  
Platinum Anode ◽  
Wide Range ◽  
Current Densities ◽  
Electro Oxidation

The conversion of uranous ion to uranyl ion at a platinum anode has been studied over a wide range of current densities and anode potentials. At high current densities, the rate of the oxidation is dependent on the uranous ion concentration and is independent of the particular current density used. At low current densities, the rate of the process increases exponentially with increases in the anode potential and temperature, but is independent of the uranyl ion concentration. It is concluded that at high current densities, the rate of oxidation is limited by the rate of diffusion of uranous ion to the anode, while at low current densities, the rate of the reaction is limited by the slowness in electron transfer between the metallic ion and the anode. A formal correlation is made between the irreversible characteristics of this system and those displayed during the electrodeposition of hydrogen and oxygen from aqueous solution.

scholarly journals Observation of current-induced switching in non-collinear antiferromagnetic IrMn3 by differential voltage measurements

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sevdenur Arpaci ◽  
Victor Lopez-Dominguez ◽  
Jiacheng Shi ◽  
Luis Sánchez-Tejerina ◽  
Francesca Garesci ◽  
...  
Keyword(s):  
Spin Orbit ◽  
High Current ◽  
Experimental Protocol ◽  
Micromagnetic Simulations ◽  
Differential Voltage ◽  
Magnetic Switching ◽  
Wide Range ◽  
Current Densities ◽  
Pass Through ◽  
Double Cross

AbstractThere is accelerating interest in developing memory devices using antiferromagnetic (AFM) materials, motivated by the possibility for electrically controlling AFM order via spin-orbit torques, and its read-out via magnetoresistive effects. Recent studies have shown, however, that high current densities create non-magnetic contributions to resistive switching signals in AFM/heavy metal (AFM/HM) bilayers, complicating their interpretation. Here we introduce an experimental protocol to unambiguously distinguish current-induced magnetic and nonmagnetic switching signals in AFM/HM structures, and demonstrate it in IrMn3/Pt devices. A six-terminal double-cross device is constructed, with an IrMn3 pillar placed on one cross. The differential voltage is measured between the two crosses with and without IrMn3 after each switching attempt. For a wide range of current densities, reversible switching is observed only when write currents pass through the cross with the IrMn3 pillar, eliminating any possibility of non-magnetic switching artifacts. Micromagnetic simulations support our findings, indicating a complex domain-mediated switching process.

A unified formalism for acoustic imaging based on microphone array measurements

2017 ◽  
Vol 16 (4-5) ◽  
pp. 431-456 ◽  
Author(s):  
Q Leclère ◽  
A Pereira ◽  
C Bailly ◽  
J Antoni ◽  
C Picard
Keyword(s):  
Microphone Array ◽  
Imaging Techniques ◽  
A Priori ◽  
Supersonic Jet ◽  
Point Of View ◽  
Problem Definition ◽  
Theoretical Point ◽  
Array Measurements ◽  
Equivalent Sources ◽  
Application Fields

The problem of localizing and quantifying acoustic sources from a set of acoustic measurements has been addressed, in the last decades, by a huge number of scientists, from different communities (signal processing, mechanics, physics) and in various application fields (underwater, aero, or vibro acoustics). This led to the production of a substantial amount of literature on the subject, together with the development of many methods, specifically adapted and optimized for each configuration and application field, the variety and sophistication of proposed algorithms being sustained by the constant increase in computational and measurement capabilities. The counterpart of this prolific research is that it is quite tricky to get a clear global scheme of the state of the art. The aim of the present work is to make an attempt in this direction, by proposing a unified formalism for different well known imaging techniques, from identification methods (acoustic holography, equivalent sources, Bayesian focusing, Generalized inverse beamforming…) to beamforming deconvolution approaches (DAMAS, CLEAN). The hypothesis, advantages and pitfalls of each approach will be established from a theoretical point of view, with a particular effort in trying to separate differences in the problem definition (a priori information, main assumptions) and in the algorithms used to find the solution. Numerical simulations will be proposed for different source configurations (coherent/incoherent/extended/sparse distributions), and an experimental illustration on a supersonic jet will be finally discussed.

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