In this work, we embarked on the research of linear two-dimensional elliptic singularly perturbed problems having positive and negative shifts in both directions of the reaction terms, whose solution ...exhibits characteristic boundary layers. The study of this class of problems was started in the mid-eighties, but all the studies were restricted to 1D. The Taylor series expansion is used to estimate decelerated terms of the problem and the emerging problem is discretized using the fitted mesh finite difference method to establish parameter uniform error estimates. The effect of positive and negative shifts on the behaviour of the solution is explained by executing numerical experiments on two test examples.
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Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
This article focuses on the investigation of two-dimensional elliptic singularly perturbed problems that incorporate positive and negative shifts, the solution of this class of problems may ...demonstrate regular/parabolic/degenerate or interior boundary layers. The goal of this article is to establish the development of numerical techniques for two-dimensional elliptic singularly perturbed problems with positive and negative shifts having regular boundary layers. The three numerical schemes are proposed to estimate the solution of this class of problems based on the fitted operator and fitted mesh finite-difference methods. The fitted operator finite difference method is analysed for convergence. The effect of shift terms on the solution behaviour is demonstrated through numerical experiments. The paper concludes by providing several numerical results that demonstrate the performance of proposed numerical schemes.
In this work, a parameter uniform numerical method is developed to find the approximate solution of time-dependent singularly perturbed convection-diffusion-reaction problems with general shift ...arguments in the space variable. The earlier work on such type of initial-interval boundary value problems is restricted to the case of small delay and advance arguments while in practical situations the shift arguments can be of arbitrary size (i.e. it may be bigger or small enough in size). The fitted mesh technique to establish parameter uniform error estimates is not extendable for the class of singularly perturbed parabolic partial differential-difference equations (SPPPDDEs) with general shift arguments in the space variable. To observe the dispersive behaviour of the solution of the problem considered in this paper, we use systematically constructed suitable denominator function for the discrete second order derivative. The motivation behind the construction of the scheme is modelling rules for non-standard finite difference methods (NSFDMs), developed by Mickens. The proposed numerical scheme is analysed for consistency and stability. It is proved that the scheme is unconditionally stable and parameter uniform convergent. The scheme is convergent for bigger shift arguments as well as for small shift arguments. The performance of the method is corroborated by numerical examples.
Purpose
Due to the increasing population and prosperity, the generation rate of municipal solid waste (MSW) has increased significantly, resulting in serious problems on public health and the ...environment. Every single person in the world is affected by the municipal solid waste management (MSWM) issue. MSWM is reaching a critical level in almost all areas of the world and seeking the development of MSW strategies for a sustainable environment. This paper aims to present the existing global status of MSW generation, composition, management and related problems.
Design/methodology/approach
A total of 59 developed and developing countries have been grouped based on their gross national income to compare the status of various MSWM technologies among them. A total of 19 selection criteria have been discussed to select appropriate MSWM technology(s) for a city/town, which affects their applicability, operational suitability and performance. All risks and challenges arising during the life cycle of the waste to energy (WtE) project have also been discussed. This paper also gives a comparative overview of different globally accepted MSWM technologies and the present market growth of all WtE technologies.
Findings
It was found that most developed countries have effectively implemented the solid waste management (SWM) hierarchy and are now focusing heavily on reducing, reusing and recycling of MSW. On the other hand, SWM has become very serious in low-income and low-middle-income countries because most of the MSW openly dumps and most countries are dependent on inadequate waste infrastructure and the informal sector. There are also some other major challenges related to effective waste policies, availability of funds, appropriate technology selection and adequacy of trained people. This study clears the picture of MSW generation, composition, management strategies and policies at the worldwide context. This manuscript could be valuable for all nations around the world where effective MSWM has not yet been implemented.
Originality/value
This study clears the picture of solid waste generation, composition, management strategies and policies at the worldwide context. This manuscript could be valuable for all nations around the world where effective MSWM has not yet been implemented. In this study, no data was generated. All supporting data were obtained from previously published papers in journals, the outcomes of the international conferences and published reports by government organizations.
In this work, a compact finite difference approach is constructed for singularly perturbed parabolic reaction diffusion problems with a retarded term. The time and space derivatives have been ...discretized using the θ-method and a compact fourth-order finite difference method on a Shishkin mesh, respectively. Parameter uniform error estimates have been calculated in the
$ L_\infty $
L
∞
norm. Some numerical examples have been considered to corroborate the theoretical results and compare the numerical results with existing methods in the literature. It is shown that the present approach provides improved results till date for the problem considered in this paper.
Prompt myocardial revascularization with percutaneous coronary intervention (PCI) reduces infarct size and improves outcomes in patients with ST-segment elevation myocardial infarction (STEMI). ...However, as much as 50% of the loss of viable myocardium may be attributed to the reperfusion injury and the associated inflammatory response.
This study sought to evaluate the effect of the interleukin-6 receptor inhibitor tocilizumab on myocardial salvage in acute STEMI.
The ASSAIL-MI trial was a randomized, double-blind, placebo-controlled trial conducted at 3 high-volume PCI centers in Norway. Patients admitted with STEMI within 6 h of symptom onset were eligible. Consenting patients were randomized in a 1:1 fashion to promptly receive a single infusion of 280 mg tocilizumab or placebo. The primary endpoint was the myocardial salvage index as measured by magnetic resonance imaging after 3 to 7 days.
We randomized 101 patients to tocilizumab and 98 patients to placebo. The myocardial salvage index was larger in the tocilizumab group than in the placebo group (adjusted between-group difference 5.6 95% confidence interval: 0.2 to 11.3 percentage points, p = 0.04). Microvascular obstruction was less extensive in the tocilizumab arm, but there was no significant difference in the final infarct size between the tocilizumab arm and the placebo arm (7.2% vs. 9.1% of myocardial volume, p = 0.08). Adverse events were evenly distributed across the treatment groups.
Tocilizumab increased myocardial salvage in patients with acute STEMI. (ASSessing the effect of Anti-IL-6 treatment in Myocardial Infarction ASSAIL-MI; NCT03004703)
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This work presents the development of numerical scheme for second-order time-dependent singularly perturbed reaction-diffusion problem with large delay in the undifferentiated term. These types of ...problems arise frequently in many areas of science and engineering that take into consideration the effect of present situation as well as the past history of the physical system. As the characteristics of the reduced problem ( = 0) corresponding to the original singularly perturbed problem considered here are parallel to the boundary of the domain this implies, parabolic layers exhibit in the solution. In this paper, we initiate the study of parabolic layers together with interior layers in the solution of singularly perturbed parabolic partial differential-difference equations due to propagation of singularity. Proposed numerical scheme comprised of finite difference scheme and piecewise uniform Shishkin mesh. The method is shown to be accurate of order
, where M and N are the number of mesh elements in time and spatial direction, respectively. Proposed numerical scheme is proved to be parameter uniform convergent in the maximum norm. Numerical experiments have been performed to show the existence of interior layer due to large state-dependent delay argument in the reaction term and to confirm the predicted theory.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
This paper is devoted to the study of singularly perturbed delay differential equations with or without a turning point. The solution of the considered class of problems may exhibit boundary or ...interior layer(s) due to the presence of the perturbation parameter, the turning point, and the delay term. Some a priori estimates are derived on the solution and its derivatives. To solve the problem numerically, a finite difference scheme on piecewise uniform Shishkin mesh along with interpolation to tackle the delay term is proposed. The solution is decomposed into regular and singular components to establish parameter uniform error estimate. It is shown that the proposed scheme converges to the solution of the continuous problem uniformly with respect to the singular perturbation parameter. The numerical experiments corroborate the theoretical findings.
In this article, we investigate the unitary dynamics of squashed entanglement and concurrence measures in Werner state and maximally entangled mixed states (MEMS) under two different Hamiltonians. ...The aim of the present study is twofold. The first part of the study deals with the dynamics under Heisenberg Hamiltonian and the second part deals under bi-linear bi-quadratic Hamiltonian which is the extension of the first Hamiltonian. In both parts, we investigate the dynamical trade-off and equilibrium points for squashed entanglement and concurrence. During the study, we also found the results of entanglement sudden death (ESD) with Heisenberg Hamiltonian in Werner state under concurrence measure. In the second part, we investigate the special result for the bi-linear bi-quadratic Hamiltonian which does not disturb squashed entanglement and concurrence in both the states and exhibits the robust character for both of the states.
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