3,593 research outputs found
Probability of Influence on Protected Ecosystems of Volyn of Development of Hotyslavsk Quarry of Chalk
Уточнено геологічну будову та гідрогеологічні умови прикордонної території України, прилеглої до Хотиславського кар’єру з видобутку піску і крейди в Білорусі. Деталізовано положення Головного європейського вододілу. У рельєфі дочетвертинної поверхні виявлено локальне структурно-ерозійне палеопідняття, яке може служити бар’єром на шляху відтоку підземних вод з території України до кар’єру. Проведено аналіз експертиз щодо негативного впливу кар’єру на довкілля у вірхів’ях р. Прип’ять і Шацькому поозер’ї. Намічено шляхи подальшого вивчення геологічного середовища в зоні впливу кар’єру і запропоновано рекомендації для перегляду його проекту. Precised the geological structure and hydrogeological conditions of the border territory of Ukraine, adjacent to quarry Hotyslavsk in the mining of sand and chalk in Belarus. Position of the Main european watershed was detailed. In relief, till quaternary surface, revealed local structural-erosion paleo uplift, which can serve as a barrier to groundwater outflow from Ukraine to quarry. Performed analysis expertises on the negative impact of the quarry to the environment in the upper river Pripyat and Shatsk lake district. Outlined ways of further studies of the geological environment in the zone of quarry and make recommendations for the revision of its project
Hydrodynamics of the Kuramoto-Sivashinsky Equation in Two Dimensions
The large scale properties of spatiotemporal chaos in the 2d
Kuramoto-Sivashinsky equation are studied using an explicit coarse graining
scheme. A set of intermediate equations are obtained. They describe
interactions between the small scale (e.g., cellular) structures and the
hydrodynamic degrees of freedom. Possible forms of the effective large scale
hydrodynamics are constructed and examined. Although a number of different
universality classes are allowed by symmetry, numerical results support the
simplest scenario, that being the KPZ universality class.Comment: 4 pages, 3 figure
Power-Law Behavior of Power Spectra in Low Prandtl Number Rayleigh-Benard Convection
The origin of the power-law decay measured in the power spectra of low
Prandtl number Rayleigh-Benard convection near the onset of chaos is addressed
using long time numerical simulations of the three-dimensional Boussinesq
equations in cylindrical domains. The power-law is found to arise from
quasi-discontinuous changes in the slope of the time series of the heat
transport associated with the nucleation of dislocation pairs and roll
pinch-off events. For larger frequencies, the power spectra decay exponentially
as expected for time continuous deterministic dynamics.Comment: (10 pages, 6 figures
Biscale Chaos in Propagating Fronts
The propagating chemical fronts found in cubic autocatalytic
reaction-diffusion processes are studied. Simulations of the reaction-diffusion
equation near to and far from the onset of the front instability are performed
and the structure and dynamics of chemical fronts are studied. Qualitatively
different front dynamics are observed in these two regimes. Close to onset the
front dynamics can be characterized by a single length scale and described by
the Kuramoto-Sivashinsky equation. Far from onset the front dynamics exhibits
two characteristic lengths and cannot be modeled by this amplitude equation. An
amplitude equation is proposed for this biscale chaos. The reduction of the
cubic autocatalysis reaction-diffusion equation to the Kuramoto-Sivashinsky
equation is explicitly carried out. The critical diffusion ratio delta, where
the planar front loses its stability to transverse perturbations, is determined
and found to be delta=2.300.Comment: Typeset using RevTeX, fig.1 and fig.4 are not available, mpeg
simulations are at
http://www.chem.utoronto.ca/staff/REK/Videos/front/front.htm
Combined potential and spin impurity scattering in cuprates
We present a theory of combined nonmagnetic and magnetic impurity scattering
in anisotropic superconductors accounting for the momentum-dependent impurity
potential. Applying the model to the d-wave superconducting state, we obtain a
quantitative agreement with the initial suppression of the critical temperature
due to Zn and Ni substitutions as well as electron irradiation defects in the
cuprates. We suggest, that the unequal pair-breaking effect of Zn and Ni may be
related to a different nature of the magnetic moments induced by these
impurities.Comment: 5 pages, 3 tables, RevTex, to be published in Phys. Rev.
Noisy Kuramoto-Sivashinsky equation for an erosion model
We derive the continuum equation for a discrete model for ion sputtering. We
follow an approach based on the master equation, and discuss how it can be
truncated to a Fokker-Planck equation and mapped to a discrete Langevin
equation. By taking the continuum limit, we arrive at the Kuramoto-Sivashinsky
equation with a stochastic noise term.Comment: latex (w/ multicol.sty), 4 pages; to appear in Physical Review E (Oct
1996
Dynamic Scaling of Ion-Sputtered Surfaces
We derive a stochastic nonlinear equation to describe the evolution and
scaling properties of surfaces eroded by ion bombardment. The coefficients
appearing in the equation can be calculated explicitly in terms of the physical
parameters characterizing the sputtering process. We find that transitions may
take place between various scaling behaviors when experimental parameters such
as the angle of incidence of the incoming ions or their average penetration
depth, are varied.Comment: 13 pages, Revtex, 2 figure
Renormalization Group Analysis of a Noisy Kuramoto-Sivashinsky Equation
We have analyzed the Kuramoto-Sivashinsky equation with a stochastic noise
term through a dynamic renormalization group calculation. For a system in which
the lattice spacing is smaller than the typical wavelength of the linear
instability occurring in the system, the large-distance and long-time behavior
of this equation is the same as for the Kardar-Parisi-Zhang equation in one and
two spatial dimensions. For the case the agreement is only qualitative.
On the other hand, when coarse-graining on larger scales the asymptotic flow
depends on the initial values of the parameters.Comment: 8 pages, 5 figures, revte
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Basic Personal Values Underlie and Give Coherence to Political Values: A Cross National Study in 15 Countries
Do the political values of the general public form a coherent system? What might be the source of coherence? We view political values as expressions, in the political domain, of more basic personal values. Basic personal values (e.g., security, achievement, benevolence, hedonism) are organized on a circular continuum that reflects their conflicting and compatible motivations. We theorize that this circular motivational structure also gives coherence to political values. We assess this theorizing with data from 15 countries, using eight core political values (e.g., free enterprise, law and order) and ten basic personal values. We specify the underlying basic values expected to promote or oppose each political value. We offer different hypotheses for the 12 non-communist and three post-communist countries studied, where the political context suggests different meanings of a basic or political value. Correlation and regression analyses support almost all hypotheses. Moreover, basic values account for substantially more variance in political values than age, gender, education, and income. Multidimensional scaling analyses demonstrate graphically how the circular motivational continuum of basic personal values structures relations among core political values. This study strengthens the assumption that individual differences in basic personal values play a critical role in political thought
Инновационные технологии упрочнения внутренних поверхностей деталей подвески тяжелонагруженных машин методами лазерного и высокочастотного индукционного воздействия
In the article innovative methods of surface hardening of internal surfaces of machine parts by laser and highfrequency induction heating are presented. The relevance of applying the methods of laser and induction hardening for the internal surfaces of heavily loaded parts of quarry equipment is proved. The results of modeling and calculation of thermal and electromagnetic fields under the influence of an external electromagnetic field and laser radiation beams are presented. The original design of a complex of equipment for processing the internal surfaces of suspension parts by external electromagnetic field is described. The optimal designs of inductors with magnetic circuits made of various materials are shown. The study of the structure and properties obtained on the internal surfaces of heavily loaded suspension parts of cars, line of the BelAZ company, treated according to the optimal modes of surface induction exposure is given. The developed original technology and equipment of laser surface hardening, which makes it possible to increase the wear resistance of heavily loaded parts, is described. Data on the implementation of research results at JSC “BELAZ” – the Management Company of the Holding “BELAZ-HOLDING” for processing a wide range of heavily loaded suspension parts are given.Представлен анализ мирового опыта в области исследований и применения инновационных методов поверхностного упрочнения деталей машиностроения с помощью лазерного и высокочастотного индукционного нагрева. Доказана актуальность применения методов лазерного и индукционного упрочнения для внутренних поверхностей тяжелонагруженных деталей карьерной техники. Представлены результаты моделирования и расчета тепловых и электромагнитных полей при воздействии внешнего электромагнитного поля и пучков лазерного излучения. Описана оригинальная конструкция комплекса оборудования для обработки внутренних поверхностей деталей подвески внешним электромагнитным полем. Показаны оптимальные конструкции индукторов с магнитопроводами из различных материалов. Приведены исследования структуры и свойств, получаемых на внутренних поверхностях тяжелонагруженных деталей подвески автомобилей семейства БелАЗ, которые обработаны по оптимальным режимам поверхностного индукционного воздействия. Описана разработанная оригинальная технология лазерного поверхностного упрочнения, позволяющая повысить износостойкость тяжелонагруженных деталей. Приведены данные по внедрению результатов исследований на ОАО «БЕЛАЗ» – управляющая компания холдинга «БЕЛАЗ-ХОЛДИНГ» для обработки широкой номенклатуры тяжелонагруженных деталей подвески
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