Magnetoviscosity of Colloidal Suspensions

1973 ◽  
Vol 51 (2) ◽  
pp. 180-194 ◽  
Author(s):  
A. C. Levi ◽  
R. F. Hobson ◽  
F. R. McCourt
Keyword(s):  
Reasonable Agreement ◽  
Colloidal Suspension ◽  
Planck Equation ◽  
Colloidal Suspensions ◽  
Theoretical Explanation ◽  
Theoretical Description ◽  
Point Of View ◽  
Theoretical Results ◽  
Ferromagnetic Particles

A theoretical description of the effect of an applied magnetic field on the viscosity of a colloidal suspension of single-domain ferromagnetic particles is given from the point of view of linearized hydrodynamics, starting from a microscopic Fokker–Planck equation. Reasonable agreement is found between theoretical results and previous experimental measurements of the effect. A comparison with an earlier theoretical explanation of the effect is given. It is found, in particular, that a consideration of the role of Brownian motion is not only desirable but crucial to a proper explanation of the magnetoviscosity effect.

scholarly journals Properties of Fourier Syntheses and New Syntheses

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 538
Author(s):  
Maria Cristina Burla ◽  
Benedetta Carrozzini ◽  
Giovanni Luca Cascarano ◽  
Carmelo Giacovazzo ◽  
Giampiero Polidori
Keyword(s):  
Structural Model ◽  
Point Of View ◽  
Special Role ◽  
Fourier Synthesis ◽  
Practical Applications ◽  
Phase Extension ◽  
Points Of View ◽  
Theoretical Results

In this study, the properties of observed, difference, and hybrid syntheses (hybrid indicates a combination of observed and difference syntheses) are investigated from two points of view. The first has a statistical nature and aims to estimate the amplitudes of peaks corresponding to the model atoms, belonging or not belonging to the target structure; the amplitudes of peaks related to the target atoms, missed or shared with the model; and finally, the quality of the background. The latter point deals with the practical features of Fourier syntheses, the special role of weighted syntheses, and their usefulness in practical applications. It is shown how the properties of the various syntheses may vary according to the available structural model and, in particular, how weighted hybrid syntheses may act like an observed and difference or a full hybrid synthesis. The theoretical results obtained in this paper suggest new Fourier syntheses using novel Fourier coefficients: their main features are first discussed from a mathematical point of view. Extended experimental applications show that they meet the basic mission of the Fourier syntheses, enhancing peaks corresponding to the missed target atoms, depleting peaks corresponding to the model atoms not belonging to the target, and significantly reducing the background. A comparison with the results obtained via the most popular modern Fourier syntheses is made, suggesting a role for the new syntheses in modern procedures for phase extension and refinement. The most promising new Fourier synthesis has been implemented in the current version of SIR2014.

scholarly journals The Role of Visibility in Pursuit/Evasion Games

2021 ◽  
Author(s):  
Athanasios Kehagias ◽  
Dieter Mitsche ◽  
Paweł Prałat
Keyword(s):  
Random Walk ◽  
Mobile Robotics ◽  
Quantitative Measure ◽  
Point Of View ◽  
Pursuit Evasion ◽  
The Cost ◽  
Theoretical Results ◽  
Discretized Model ◽  
Cops And Robber

The cops-and-robber (CR) game has been used in mobile robotics as a discretized model (played on a graph G) of pursuit/evasion problems. The “classic” CR version is a perfect information game: the cops’ (pursuer’s) location is always known to the robber (evader) and vice versa. Many variants of the classic game can be defined: the robber can be invisible and also the robber can be either adversarial (tries to avoid capture) or drunk (performs a random walk). Furthermore, the cops and robber can reside in either nodes or edges of G. Several of these variants are relevant as models or robotic pursuit/evasion. In this paper, we first define carefully several of the variants mentioned above and related quantities such as the cop number and the capture time. Then we introduce and study the cost of visibility (COV), a quantitative measure of the increase in difficulty (from the cops’ point of view) when the robber is invisible. In addition to our theoretical results, we present algorithms which can be used to compute capture times and COV of graphs which are analytically intractable. Finally, we present the results of applying these algorithms to the numerical computation of COV.

scholarly journals The Role of Visibility in Pursuit/Evasion Games

2021 ◽  
Author(s):  
Athanasios Kehagias ◽  
Dieter Mitsche ◽  
Paweł Prałat
Keyword(s):  
Random Walk ◽  
Mobile Robotics ◽  
Quantitative Measure ◽  
Point Of View ◽  
Pursuit Evasion ◽  
The Cost ◽  
Theoretical Results ◽  
Discretized Model ◽  
Cops And Robber

The cops-and-robber (CR) game has been used in mobile robotics as a discretized model (played on a graph G) of pursuit/evasion problems. The “classic” CR version is a perfect information game: the cops’ (pursuer’s) location is always known to the robber (evader) and vice versa. Many variants of the classic game can be defined: the robber can be invisible and also the robber can be either adversarial (tries to avoid capture) or drunk (performs a random walk). Furthermore, the cops and robber can reside in either nodes or edges of G. Several of these variants are relevant as models or robotic pursuit/evasion. In this paper, we first define carefully several of the variants mentioned above and related quantities such as the cop number and the capture time. Then we introduce and study the cost of visibility (COV), a quantitative measure of the increase in difficulty (from the cops’ point of view) when the robber is invisible. In addition to our theoretical results, we present algorithms which can be used to compute capture times and COV of graphs which are analytically intractable. Finally, we present the results of applying these algorithms to the numerical computation of COV.

Elucidation of block boundaries as the dissolution channels in hydrated cement

1978 ◽  
Vol 36 (1) ◽  
pp. 484-485
Author(s):  
N.V. Belov ◽  
U.I. Papiashwili ◽  
B.E. Yudovich
Keyword(s):  
Liquid Phase ◽  
Grain Boundaries ◽  
Benzoyl Peroxide ◽  
Phase Contrast ◽  
Active Role ◽  
Point Of View ◽  
Hardened Cement ◽  
Hydrated Cement ◽  
Hardened Cement Paste

It has been almost universally adopted that dissolution of solids proceeds with development of uniform, continuous frontiers of reaction.However this point of view is doubtful / 1 /. E.g. we have proved the active role of the block (grain) boundaries in the main phases of cement, these boundaries being the areas of hydrate phases' nucleation / 2 /. It has brought to the supposition that the dissolution frontier of cement particles in water is discrete. It seems also probable that the dissolution proceeds through the channels, which serve both for the liquid phase movement and for the drainage of the incongruant solution products. These channels can be appeared along the block boundaries.In order to demonsrate it, we have offered the method of phase-contrast impregnation of the hardened cement paste with the solution of methyl metacrylahe and benzoyl peroxide. The viscosity of this solution is equal to that of water.

Whatever Happened to the Cambridge Capital Theory Controversies? (With comments by L. Pasinetti, F. Fisher, J. Felipe and J. McCombie, R. Greenfield and reply by the authors)

2009 ◽  
pp. 4-27
Author(s):  
A. Cohen ◽  
G. Harcourt
Keyword(s):  
Economic Theory ◽  
Economic Thought ◽  
Point Of View ◽  
Chronological Order ◽  
Capital Theory

The article written by the well-known theorists and historians of economic thought contains a detailed overview of the Cambridge capital controversy, which had raged from the mid-1950-s through the mid-1970-s. The authors track the origins of the controversy and cover arguments of both sides in chronological order. From their point of view, the discussion hasnt been resolved, and its main underlying aspects were ideological beliefs and fundamental methodological controversies on the nature of equilibrium and on the role of time in economic theory. The article is published with comments written by other leading theoreticians.

УКРАЇНОЗНАВЧИЙ ОСВІТНІЙ ЧИННИК В УМОВАХ СУЧАСНОЇ УКРАЇНСЬКОЇ МАСОВОЇ КУЛЬТУРИ

2019 ◽  
pp. 22-29
Author(s):  
Н. В. Фрадкіна
Keyword(s):  
Mass Culture ◽  
Personal Development ◽  
Negative Impact ◽  
Educational Process ◽  
Point Of View ◽  
Character Trait ◽  
Main Task ◽  
Leading Role ◽  
The Individual

The purpose and tasks of the work are to analyze the contemporary Ukrainian mass culture in terms of its value and humanistic components, as well as the importance of cultural studies and Ukrainian studies in educational disciplines for the formation of a holistic worldview of modern youth.Analysis of research and publications. Scientists repeatedly turned to the problems of the role of spirituality in the formation of society and its culture. This problem is highlighted in the publications by O. Losev, V. Lytvyn, D. Likhachev, S. Avierintsev, M. Zakovych, I. Stepanenko and E. Kostyshyn.Experts see the main negative impact of mass culture on the quality approach, which determines mass culture through the market, because mass culture, from our point of view, is everything that is sold and used in mass demand.One of the most interesting studies on this issue was the work by the representatives of Frankfurt School M. Horkheimer and T. Adorno «Dialectics of Enlightenment» (1947), devoted to a detailed analysis of mass culture. Propaganda at all socio-cultural levels in the form is similar in both totalitarian and democratic countries. It is connected, according to the authors, with the direction of European enlightenment. The tendency to unify people is a manifestation of the influence of mass culture, from cinema to pop. Mass culture is a phenomenon whose existence is associated with commerce (accumulation in any form – this is the main feature of education), in general, the fact that it exists in this form is related to the direction of the history of civilization.Modern mass culture, with its externally attractive and easily assimilated ideas and symbols, appealing to the trends of modern fashion, becomes a standard of prestigious consumption, does not require intense reflection, allows you to relax, distract, not teach, but entertains, preaches hedonism as the main spiritual value. And as a consequence, there are socio-cultural risks: an active rejection of other people, which leads to the formation of indifference; cruelty as a character trait; increase of violent and mercenary crime; increase in the number of alcohol and drug addicts; anti-patriotism; indifference to the values of the family and as a result of social orphanhood and prostitution.Conclusions, perspectives of research. Thus, we can conclude that modern Ukrainian education is predominantly formed by the values of mass culture. Namely, according to the «Dialectic» by Horkheimer and Adorno, «semi-enlightenment becomes an objective spirit» of our modern society.It is concluded that only high-quality education can create the opposite of the onset of mass culture and the destruction of spirituality in our society. It is proved that only by realizing the importance of cultivating disciplines in the educational process and the spiritual upbringing of the nation, through educational reforms, humanitarian knowledge will gradually return to student audiences.Formation of youth occurs under the influence of social environment, culture, education and self-education. The optimal combination of these factors determines both the process of socialization itself and how successful it will be. In this context, one can see the leading role of education and upbringing. It turns out that the main task of modern education is to spread its influence on the development of spiritual culture of the individual, which eventually becomes a solid foundation for the formation of the individual. Such a subject requires both philosophical and humanitarian approaches in further integrated interdisciplinary research, since the availability of such research will provide the theoretical foundation for truly modern educational and personal development.

The role of graining in ensuring food security

2020 ◽  
pp. 75-79
Author(s):  
R. M. Gambarova
Keyword(s):  
Food Security ◽  
Comparative Analysis ◽  
Systems Approach ◽  
Point Of View ◽  
Government Support ◽  
Grain Production ◽  
The Government ◽  
Favorable Conditions ◽  
Grain Farms

Relevance. Grain is the key to strategic products to ensure food security. From this point of view, the creation of large grain farms is a matter for the country's selfsufficiency and it leading to a decrease in financial expense for import. Creation of such farms creates an abundance of productivity from the area and leads to obtaining increased reproductive seeds. The main policy of the government is to minimize dependency from import, create abundance of food and create favorable conditions for export potential.The purpose of the study: the development of grain production in order to ensure food security of the country and strengthen government support for this industry.Methods: comparative analysis, systems approach.Results. As shown in the research, if we pay attention to the activities of private entrepreneurship in the country, we can see result of the implementation of agrarian reforms after which various types of farms have been created in republic.The role of privateentrepreneurshipinthedevelopmentofproduction is great. Тhe article outlines the sowing area, production, productivity, import, export of grain and the level of selfsufficiency in this country from 2015 till 2017.

Tauchnitz for Translators. The Circulation of English-language Literature in Finland

2019 ◽  
Vol 16 (2-3) ◽  
pp. 161-179
Author(s):  
Outi Paloposki
Keyword(s):  
Foreign Language ◽  
English Language ◽  
Book History ◽  
Language Skills ◽  
Point Of View ◽  
Book Production ◽  
German Publisher ◽  
Language Literature ◽  
Selection Of

The article looks at book production and circulation from the point of view of translators, who, as purchasers and readers of foreign-language books, are an important mediating force in the selection of literature for translation. Taking the German publisher Tauchnitz's series ‘Collection of British Authors’ and its circulation in Finland in the nineteenth and early twentieth century as a case in point, the article argues that the increased availability of English-language books facilitated the acquiring and honing of translators' language skills and gradually diminished the need for indirect translating. Book history and translation studies meet here in an examination of the role of the Collection in Finnish translators' work.

Physical capital stock, technological upgrading and modernisation in Hungary

2005 ◽  
Vol 55 (2) ◽  
pp. 201-221 ◽  
Author(s):  
Andrea Szalavetz
Keyword(s):  
Capital Accumulation ◽  
Physical Capital ◽  
Developed Countries ◽  
Point Of View ◽  
Technology Generation ◽  
Development Policies ◽  
Specific Factors ◽  
Physical Capital Accumulation

This paper discusses the relation between the quality and quantity indicators of physical capital and modernisation. While international academic literature emphasises the role of intangible factors enabling technology generation and absorption rather than that of physical capital accumulation, this paper argues that the quantity and quality of physical capital are important modernisation factors, particularly in the case of small, undercapitalised countries that recently integrated into the world economy. The paper shows that in Hungary, as opposed to developed countries, the technological upgrading of capital assets was not necessarily accompanied by the upgrading of human capital i.e. the thesis of capital skill complementarity did not apply to the first decade of transformation and capital accumulation in Hungary. Finally, the paper shows that there are large differences between the average technological levels of individual industries. The dualism of the Hungarian economy, which is also manifest in terms of differences in the size of individual industries' technological gaps, is a disadvantage from the point of view of competitiveness. The increasing differences in the size of the technological gaps can be explained not only with industry-specific factors, but also with the weakness of technology and regional development policies, as well as with institutional deficiencies.

Clustering-Triggered Efficient Room Temperature Phosphorescence from Nonconventional Luminophores

2019 ◽  
Author(s):  
Shuyuan Zheng ◽  
Taiping Hu ◽  
Xin Bin ◽  
Yunzhong Wang ◽  
Yuanping Yi ◽  
...  
Keyword(s):  
Room Temperature ◽  
High Efficiency ◽  
Spin Orbit Coupling ◽  
Design Rationale ◽  
Emission Mechanism ◽  
Room Temperature Phosphorescence ◽  
Electronic Interactions ◽  
Energy Gaps ◽  
Theoretical Results

Pure organic room temperature phosphorescence (RTP) and luminescence from nonconventional luminophores have gained increasing attention. However, it remains challenging to achieve efficient RTP from unorthodox luminophores, on account of the unsophisticated understanding of the emission mechanism. Here we propose a strategy to realize efficient RTP in nonconventional luminophores through incorporation of lone pairs together with clustering and effective electronic interactions. The former promotes spin-orbit coupling and boost the consequent intersystem crossing, whereas the latter narrows energy gaps and stabilizes the triplets, thus synergistically affording remarkable RTP. Experimental and theoretical results of urea and its derivatives verify the design rationale. Remarkably, RTP from thiourea solids with unprecedentedly high efficiency of up to 24.5% is obtained. Further control experiments testify the crucial role of through-space delocalization on the emission. These results would spur the future fabrication of nonconventional phosphors, and moreover should advance understanding of the underlying emission mechanism.<br>

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