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ردیف | عنوان | نوع |
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1 |
Significance of variable electrical conductivity on non-Newtonian fluid flow between two vertical plates in the coexistence of Arrhenius energy and exothermic chemical reaction
Noneاهمیت رسانایی الکتریکی متغیر بر جریان سیال غیرنیوتنی بین دو صفحه عمودی در همزیستی انرژی آرنیوس و واکنش شیمیایی گرمازا-2021 The present study is designed to model the combustible materials of two vertical plates with Arrhenius energy
and exothermic chemical reaction. The magnetohydrodynamics fluid is considered to experience an exothermic
chemical reaction inside the channel. Additional effects incorporated to the novelty of the model are the
rheological Casson fluid term and the variable electrical conductivity. The model has transformed appropriately
to its dimensionless form using similarity renovation and the Solution is numerically obtained using the
Chebyshev collocation scheme. The influences of controlling parameters on the fluid velocity, temperature,
concentration, and heat transfer rate are analyzed using graph and quantitatively discussed. Analyses reveal
that the activation energy declines the fluid velocity, while the existence of the variable electrical conductivity
parameter has the opposite effect. The heat transfer rate is enhanced with higher values of concentration
buoyancy (Gc) and variable electrical conductivity parameter. Moreover, the non-Newtonian Casson fluid
parameter shows a solid characteristic when yield stress is more than the shear stress. Thermal and chemical
engineering, as well as service-worthiness of industrial products, will benefit from the findings of this study.
Keywords: Magnetohydrodynamics fluid | Rheological Casson fluid | Arrhenius energy and exothermic chemical | reaction |
مقاله انگلیسی |
2 |
Intrusive acceleration strategies for uncertainty quantificationfor hyperbolic systems of conservation laws
استراتژی های شتابزنی سرعتی برای تعیین کمیت عدم اطمینان برای سیستم هایپربولیک قوانین حفاظت-2020 Methods for quantifying the effects of uncertainties in hyperbolic problems can be divided into intrusive and non-intrusive techniques. Non-intrusive methods allow the usage of a given deterministic solver in a black-box manner, while being embarrassingly parallel. On the other hand, intrusive modifications allow for certain acceleration techniques. Moreover, intrusive methods are expected to reach a given accuracy with a smaller number of unknowns compared to non-intrusive techniques. This effect is amplified in settings with high dimensional uncertainty. A downside of intrusive methods is the need to guarantee hyperbolicity of the resulting moment system. In contrast to stochastic-Galerkin (SG), the Intrusive Polynomial Moment (IPM) method is able to maintain hyperbolicity at the cost of solving an optimization problem in every spatial cell and every time step.
In this work, we propose several acceleration techniques for intrusive methods and study their advantages and shortcomings compared to the non-intrusive Stochastic Collocation method. When solving steady problems with IPM, the numerical costs arising from repeatedly solving the IPM optimization problem can be reduced by using concepts from PDE-constrained optimization. Integrating the iteration from the numerical treatment of the optimization problem into the moment update reduces numerical costs, while preserving local convergence. Additionally, we propose an adaptive implementation and efficient parallelization strategy of the IPM method. The effectiveness of the proposed adaptations is demonstrated for multi-dimensional uncertainties in fluid dynamics applications, resulting in the observation of requiring a smaller number of unknowns to achieve a given accuracy when using intrusive methods. Furthermore, using the proposed acceleration techniques, our implementation reaches a given accuracy faster than Stochastic Collocation. Keywords: Uncertainty quantification | Hyperbolic conservation laws | Intrusive | Stochastic-Galerkin | Collocation | Intrusive Polynomial Moment Method |
مقاله انگلیسی |
3 |
Thermal runaway and thermodynamic second law of a reactive couple stress hydromagnetic fluid with variable properties and Navier slips
قانون دوم گرمازدایی و ترمودینامیکی یک مایع هیدرومغناطیسی و فشار چند واکنشی با خواص متغیر و لغزش Navier-2020 Theoretical solutions of a thermal runaway and irreversibility thermodynamic analysis of a couple stress hydromagnetic reactive fluid with Navier slip conditions and variable prop- erties are examined. Ignoring the material assumption, the fluid is taken to be actively exothermic under Bimolecular kinetics. The dimensionless modeled equations are analyti- cally solved using weighted residual method coupled with collocation techniques to obtain the bifurcation branch chain for criticality, irreversibility rate, flow rate and heat distribu- tion solutions. It was noticed that the variable properties have no significant influence on the couple stress reactive liquid and heat distribution. Also, at high thermodynamic equi- librium, entropy generation in the system is minimized. This study results will help in un- derstanding the relationship that exist between thermal explosion and thermal branched- chain in managing industrial engines in order to avoid system blow up. Keywords: Thermal runaway | Irreversibility | Non-Newtonian fluid | Chemical kinetics | Hydromagnetic |
مقاله انگلیسی |
4 |
Textual strategies of forensic psychiatrists: A corpus-based analysis of how the language of psychiatry is reconciled with the language of law in polish forensic psychiatric opinions
راهبردهای متنی روانپزشکان قانونی: تحلیلی مبتنی بر پیکره از چگونگی تطبیق زبان روانپزشکی با زبان قانون در نظرات روانپزشکی قانونی لهستانی-2020 The role of an expert forensic psychiatrist is likened with that of a translator: their task is to translate the language of medicine into the language of law. The aim of the article was to reconstruct the textual strategies adopted by forensic psychiatrists in terms of reconciling the discourses of law and medicine. The analysis covered 65 opinions/reports issued at a psychiatric reference centre in Poland. Thanks to the application of the innovative corpus linguistics methodology, the singularities of forensic psychiatric opinions as a genre have been captured and the degree of its conventionalization has been assessed. The findings indicate that psychiatric opinions have not yet achieved the status of a homogenous genre, and the standardization and formalization processes have only reached the structural level. The expert psychiatrists constrained the presence of the author’s voice and did not use the narrative form in their opinions. The analysis also captured the ethical challenges related to the dual role of forensic psychiatrists as medical doctors and representatives of the judicial system. Keywords: Forensic psychiatry | Forensic psychiatric evaluation | Corpus linguistics | Keyword analysis | Collocations | Stylometric analysis |
مقاله انگلیسی |
5 |
Flexural vibration of imperfect functionally graded beams based on Timoshenko beam theory: Chebyshev collocation method
ارتعاش خمشی ناقص تیرهای هدفمند بر اساس تئوری پرتو ایموشنکو: روش نظم چبیشف-2015 Flexural vibration analysis of beams made
of functionally graded materials (FGMs) with various
boundary conditions is considered in this paper. Due to
technical problems during FGM fabrication, porosities
and micro-voids can be created inside FGM samples
which may lead to the reduction in density and
strength of materials. In this investigation, the FGM
beams are assumed to have even and uneven distributions
of porosities over the beam cross-section. The
modified rule of mixture is used to approximate
material properties of the FGM beams including the
porosity volume fraction. In order to cover the effects
of shear deformation, axial and rotary inertia, the
Timoshenko beam theory is used to form the coupled
equations of motion for describing dynamic behavior
of the beams. To solve such a problem, Chebyshev
collocation method is employed to find natural
frequencies of the beams supported by different end
conditions. Based on numerical results, it is revealed
that FGM beams with even distribution of porosities
have more significant impact on natural frequencies
than FGM beams with uneven porosity distribution.
Keywords Imperfect FGM beam Vibration
Natural frequency Chebyshev collocation method |
مقاله انگلیسی |