2,589 research outputs found
Slanted matrices, Banach frames, and sampling
In this paper we present a rare combination of abstract results on the
spectral properties of slanted matrices and some of their very specific
applications to frame theory and sampling problems. We show that for a large
class of slanted matrices boundedness below of the corresponding operator in
for some implies boundedness below in for all . We use
the established resultto enrich our understanding of Banach frames and obtain
new results for irregular sampling problems. We also present a version of a
non-commutative Wiener's lemma for slanted matrices
Наукові підходи до визначення економічного змісту поняття «бюджетний менеджмент» (The scientific approach to determine the economic content of the budget management concept)
У статті проаналізовано наукові погляди на тлумачення сутності поняття «бюджетний менеджмент». На основі критичного аналізу та узагальнення існуючих поглядів вітчизняних і зарубіжних дослідників сформульоване
власне авторське бачення дефініції бюджетного менеджменту, що ґрунтується на її морфологічній декомпозиції із виділенням мети, завдань, суб’єктів, об’єктів, принципів та функцій бюджетного менеджменту.
(In the article it was analyzed the scientific opinions on the interpretation of the essence of the concept of «budget management».
On the basis of a critical analysis and synthesis of existing views of domestic and foreign researchers to formulate their own vision of the author’s definition of budget management, which is based on its morphological decomposition, for the purposes of allocation, task, subjects, objects, principles and budget management functions.
The presence of valine at residue 129 in human prion protein accelerates amyloid formation
The polymorphism at residue 129 of the human PRNP gene modulates disease susceptibility and the clinicopathological phenotypes in human transmissible spongiform encephalopathies. The molecular mechanisms by which the effect of this polymorphism are mediated remain unclear. It has been shown that the folding, dynamics and stability of the physiological, alpha-helix-rich form of recombinant PrP are not affected by codon 129 polymorphism. Consistent with this, we have recently shown that the kinetics of amyloid formation do not differ between protein containing methionine at codon 129 and valine at codon 129 when the reaction is initiated from the a-monomeric PrPC-like state. In contrast, we have shown that the misfolding pathway leading to the formation of beta-sheet-rich, soluble oligomer waS favoured by the presence of methionine, compared with valine, at position 129. In the present work, we examine the effect of this polymorphism on the kinetics of an alternative misfolding pathway, that of amyloid formation using partially folded PrP allelomorphs. We show that the valine 129 allelomorph forms amyloids with a considerably shorter lag phase than the methionine 129 allelomorph both under spontaneous conditions and when seeded with pre-formed amyloid fibres. Taken together, our studies demonstrate that the effect of the codon 129 polymorphism depends on the specific misfolding pathway and on the initial conformation of the protein. The inverse propensities of the two allelomorphs to misfold in vitro through the alternative oligomeric and amyloidogenic pathways could explain some aspects of prion diseases linked to this polymorphism such as age at onset and disease incubation time. (c) 2005 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved
The generalized correlation for the evaluation of the influence of the Stefan flow on the heat transfer coefficient
The analytical equations for the steady-state heat-and-mass transfer in the steam evaporation/condensation processes from the steam-gas mixtures on the planar and spherical surfaces are derived. The vapor flow through the motionless dry gas is considered according to the method proposed by Maxwell for the solution of the diffusion problems. The relationships for the calculation of the coefficients taking into account an increase in the mass output and an increase or a decrease in the heat emission (depending on the directions of the heat-and-mass flows) as a result of the influence of the Stefan flow are presented. The derived relationships can be used to calculate the apparatuses in which the steam evaporation or condensation from the steam-gas mixture occurs (the coolers of the vapor from deaerators, the apparatuses for the deep utilization of the heat of the combustion products, the condensation boilers, etc.). © 2013 Pleiades Publishing, Inc
Harmonic analysis of causal operators and their spectral properties
The definition and study of causal operators are based on the
representation theory of group algebras. We study the structure of the spectra
of causal operators, obtain conditions for causal invertibility and state criteria for a
causal operator to belong to the radical
The influence of the gas-distributing grid diameter on the transition velocity and hydrodynamics of the bottom layer in circulating fluidized bed installations
The dependences of dimensionless fluidization velocities separating bubble, transition, and fast fluidization regimes on the properties of dispersed material for particles belonging to groups B and D (according to D. Geldart's classification) are presented. Correspondence between the considered dependences and experimental data obtained by different researchers and their correlation with critical fluidization velocities and particle terminal velocities are shown. The hydrodynamic mechanisms governing the saturation of fluidized bed with bubbles on reaching the transition fluidization velocity in installations having different sizes are considered. Factors due to which a bottom bubble layer disappears in narrow installations and is retained on large-diameter grids in an intense channel forming mode are explained. Experimental data are presented from which it is seen that the bubble layer hydrodynamics depends on the gas-distributing grid diameter and that this diameter has an insignificant influence on the fluidization velocity during the transition from a bubble to fast fluidization regime. © 2013 Pleiades Publishing, Inc
Transients in a circulating fluidized bed boiler
Transients in a circulating fluidized bed boiler firing biomass are considered. An attempt is made to describe transients with the use of concepts applied in the automatic control theory. The parameters calculated from an analysis of unsteady heat balance equations are compared with the experimental data obtained in the 12-MW boiler of the Chalmers University of Technology. It is demonstrated that these equations describe the transient modes of operation with good accuracy. Dependences for calculating the time constants of unsteady processes are obtained. © 2013 Pleiades Publishing, Inc
Generation and reduction of nitrogen oxides in firing different kinds of fuel in a circulating fluidized bed
The processes through which nitrogen oxides are generated and reduced in the course of firing different kinds of fuel in a circulating fluidized bed are addressed. All experimental studies were carried by the authors on their own laboratory installations. To construct a model simulating the generation of nitrogen oxides, the fuel combustion process in a fluidized bed was subdivided into two stages: combustion of volatiles and combustion of coke residue. The processes through which nitrogen oxides are generated and reduced under the conditions of firing fuel with shortage of oxygen (which is one of efficient methods for reducing nitrogen oxide emissions in firing fuel in a fluidized bed) are considered. © 2013 Pleiades Publishing, Inc
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