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Finite Deformation, Finite strain Nonlinear Dynamics and Dynamic Bifurcation in TVE solids with Rheology

Applied Mathematics 2024年第1期15卷 108-168页

作者： Karan s. surana sri sai Charan mathi Department of Mechanical Engineering University of Kansas Lawrence US

This paper presents a mathematical model consisting of conservation and balance laws (CBL) of classical continuum mechanics (CCM) and ordered rate constitutive theories in Lagrangian description derived using entropy inequality and the representation theorem for thermoviscoelastic solids (TVEs) with rheology. The CBL and the constitutive theories take into account finite deformation and finite strain deformation physics and are based on contravariant deviatoric second Piola-Kirchhoff stress tensor and its work conjugate covariant Green’s strain tensor and their material derivatives of up to order m and n respectively. All published works on nonlinear dynamics of TVEs with rheology are mostly based on phenomenological mathematical models. In rare instances, some aspects of CBL are used but are incorrectly altered to obtain mass, stiffness and damping matrices using space-time decoupled approaches. In the work presented in this paper, we show that this is not possible using CBL of CCM for TVEs with rheology. Thus, the mathematical models used currently in the published works are not the correct description of the physics of nonlinear dynamics of TVEs with rheology. The mathematical model used in the present work is strictly based on the CBL of CCM and is thermodynamically and mathematically consistent and the space-time coupled finite element methodology used in this work is unconditionally stable and provides solutions with desired accuracy and is ideally suited for nonlinear dynamics of TVEs with memory. The work in this paper is the first presentation of a mathematical model strictly based on CBL of CCM and the solution of the mathematical model is obtained using unconditionally stable space-time coupled computational methodology that provides control over the errors in the evolution. Both space-time coupled and space-time decoupled finite element formulations are considered for obtaining solutions of the IVPs described by the mathematical model and are presented i

关键词： Thermoviscoelasticity Rheology Memory Finite strain Finite Deformation Nonlinear Dynamics Dynamic Bifurcation Ordered Rate Theories

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Composite recommendations： from items to packages

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Frontiers of Computer science 2012年第3期6卷 264-277页

作者： Min XIE laks V. s. laksHMANAN Peter T. WOOD Department of Computer science University of British Columbia Vancouver V6T 1Z4 Canada Department of Computer science and Information systems Birkbeck University of London London WCIE 7HX UK

Classical recommender systems provide users with a list of recommendations where each recommendation consists of a single item, e.g., a book or DVD. However, sev- eral applications can benefit from a system capable of recom- mending packages of items, in the form of sets. sample appli- cations include travel planning with a limited budget （price or time） and twitter users wanting to select worthwhile tweeters to follow, given that they can deal with only a bounded num- ber of tweets. In these contexts, there is a need for a system that can recommend the top-k packages for the user to choose from. Motivated by these applications, we consider composite recommendations, where each recommendation comprises a set of items. Each item has both a value （rating） and a cost associated with it, and the user specifies a maximum total cost （budget） for any recommended set of items. Our composite recommender system has access to one or more component recommender systems focusing on different do- mains, as well as to information sources which can provide the cost associated with each item. Because the problem of deciding whether there is a recommendation （package） whose cost is under a given budget and whose value exceeds some threshold is NP-complete, we devise several approximation algorithms for generating the top-k packages as recommen- dations. We analyze the efficiency as well as approximation quality of these algorithms. Finally, using two real and two synthetic datasets, we subject our algorithms to thorough ex- perimentation and empirical analysis. Our findings attest tothe efficiency and quality of our approximation algorithms for the top-k packages compared to exact algorithms.

关键词： recommendation algorithms optimization,top-k query processing

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Aristotle＇s Immovable Movers： A sketch

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Frontiers of Philosophy in China 2015年第2期10卷 273-286页

作者： André laks Department of Philosophy Panamerican University Col. Insurgentes Mixcoac CP03920 México D.F.

In keeping with a view that is explicitly formulated by Aristotle in his Motion of Animals, general kinetic principles must be specified according to the different types of movable entities existing in the universe. At issue, essentially, are the motions of the stars and the motions of animals. Whereas the cosmological immovable mover is the object of two complementary analyses （in Bk. Ⅷ of Physics and in Chs. 6 and 7 of Bk. Ⅻ of Metaphysics）, information on the immovability of the first mover responsible for animal motion is to be found in the psychological and psycho-physiological treatises （On the soul, in Bk. Ⅰ, Chs. 3 and 4, and in Bk. Ⅲ, Ch. 10 and in Ch. 6 of the Motion of Animals）. But it is also found in Ch. 7, Bk. Ⅻ of the Metaphysics, in the very context of the argument concerning the absolutely first immovable mover of the world. This suggests that the two types of motion, that of the stars and that of animals, however distinct the arguments about them are, rest on a single scheme, and maybe even on a common principle. This is liable to surprise us, as much as stars and animals appear to us to belong to heterogeneous orders of reality. But the situation is different for Aristotle, who, as attentive as he is to differences, tends nonetheless to conceive the stars as living things of a particular kind. This fact is the source of a series of difficulties that Aristotle generously left for his many commentators to solve. Aim of this text, which was initially directed to a larger audience, is to set some of these complex issues in both simple and up to date terms.

关键词： Aristotle immovable movers final cause efficient cause soul animal motion

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Finite Deformation, Finite strain Nonlinear Dynamics and Dynamic Bifurcation in TVE solids

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Applied Mathematics 2023年第12期14卷 773-838页

作者： Karan s. surana sri sai Charan mathi Department of Mechanical Engineering Univeristy of Kansas Lawrence KS USA

This paper presents the mathematical model consisting of conservation and balance laws (CBL) of classical continuum mechanics (CCM) and the constitutive theories derived using entropy inequality and representation theorem for thermoviscoelastic solids (TVEs) matter without memory. The CBL and the constitutive theories take into account finite deformation and finite strain deformation physics. This mathematical model is thermodynamically and mathematically consistent and is ideally suited to study nonlinear dynamics of TVEs and dynamic bifurcation and is used in the work presented in this paper. The finite element formulations are constructed for obtaining the solution of the initial value problems (IVPs) described by the mathematical models. Both space-time coupled as well as space-time decoupled finite element methods are considered for obtaining solutions of the IVPs. space-time coupled finite element formulations based on space-time residual functional (sTRF) that yield space-time variationally consistent space-time integral forms are considered. This approach ensures unconditional stability of the computations during the entire evolution. In the space-time decoupled finite element method based on Galerkin method with weak form for spatial discretization, the solutions of nonlinear ODEs in time resulting from the decoupling of space and time are obtained using Newmark linear acceleration method. Newton’s linear method is used to obtain converged solution for the nonlinear system of algebraic equations at each time step in the Newmark method. The different aspects of the deformation physics leading to the factors that influence nonlinear dynamic response and dynamic bifurcation are established using the proposed mathematical model, the solution method and their validity is demonstrated through model problem studies presented in this paper. Energy methods and superposition techniques in any form including those used in obtaining solutions are neither advocated nor

关键词： Thermodynamic Consistency Dynamic Bifurcation static Bifurcation Nonlinear Formulation Finite strain Finite Deformation Thermoviscoelastic Classical Continuum Mechanics Conservation and Balance Laws Nonlinear Damping

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Efficacy and tolerability of a polysaccharide-resin-honey based cough syrup as compared to carbocysteine syrup for children with colds: a randomized, single-blinded,multicenter study

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World Journal of Pediatrics 2017年第1期13卷 27-33页

作者： Herman Avner Cohen Moshe Hoshen shmuel Gur Arie Bahir Yoseph laks Hannah Blau Pediatric Ambulatory Community Clinic Petah—TikvaIsrael sackler Faculty of Medicine Tel.Aviv UniversityTel—AvivIsrael Clalit Research Institute Chief Physician's OfficeClalit Health ServicesTel AvivIsrael Pediatric Ambulatory Community Clinic Kefar SabaIsrael Pediatric Ambulatory Community Clinic Bat YamIsrael Pediatric Ambulatory Community Clinic Ramat Aviv.Israel Pulmonary Institute Schneider Children Medical Center ofIsrael.Petah Tikva.Israel.

Background:Available pediatric treatments for acute cough are limited by lack of demonstrated *** objective of this trial is to compare the effects of a poIysaccharide—resin-honey based cough syrup,and carbocysteine ... 详细信息

关键词： cough children upper respiratory tract infection

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Thermodynamic Consistency of Plate and shell Mathematical Models in the Context of Classical and Non-Classical Continuum Mechanics and a Thermodynamically Consistent New Thermoelastic Formulation

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American Journal of Computational Mathematics 2020年第2期10卷 167-220页

作者： Karan s. surana sri sai Charan mathi Department of Mechanical Engineering University of Kansas Lawrence Kansas

Inclusion of dissipation and memory mechanisms, non-classical elasticity and thermal effects in the currently used plate/shell mathematical models require that we establish if these mathematical models can be derived using the conservation and balance laws of continuum mechanics in conjunction with the corresponding kinematic assumptions. This is referred to as thermodynamic consistency of the mathematical models. Thermodynamic consistency ensures thermodynamic equilibrium during the evolution of the deformation. When the mathematical models are thermodynamically consistent, the second law of thermodynamics facilitates consistent derivations of constitutive theories in the presence of dissipation and memory mechanisms. This is the main motivation for the work presented in this paper. In the currently used mathematical models for plates/shells based on the assumed kinematic relations, energy functional is constructed over the volume consisting of kinetic energy, strain energy and the potential energy of the loads. The Euler’s equations derived from the first variation of the energy functional for arbitrary length when set to zero yield the mathematical model(s) for the deforming plates/shells. Alternatively, principle of virtual work can also be used to derive the same mathematical model(s). For linear elastic reversible deformation physics with small deformation and small strain, these two approaches, based on energy functional and the principle of virtual work, yield the same mathematical models. These mathematical models hold for reversible mechanical deformation. In this paper, we examine whether the currently used plate/shell mathematical models with the corresponding kinematic assumptions can be derived using the conservation and balance laws of classical or non-classical continuum mechanics. The mathematical models based on Kirchhoff hypothesis (classical plate theory, CPT) and first order shear deformation theory (FsDT) that are representative of most mathema

关键词： Plate and shell Mathematical Models Energy Functional Thermodynamic Consistency Classical Continuum Mechanics Non-Classical Continuum Mechanics Internal Rotations Cosserat Rotations Principle of Virtual Work

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半导体用聚酰亚胺薄膜的表征

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电子元件与材料 1986年第6期 40-43+30页

作者： A.M.Wilson D.laks s.M.Davis 蒋启泰

聚酰亚胺树脂作为一类化学品早在1926年就已制得。它们作为一种在250℃以上仍保持其电气和机械特性的塑料绝缘体而应用于电子工业也是早已得到公认。Harada及其在日立(Hitachi)中央研究实验室的同事曾就聚酰亚胺异吲哚喹唑啉二酮(简称P... 详细信息

聚酰亚胺树脂作为一类化学品早在1926年就已制得。它们作为一种在250℃以上仍保持其电气和机械特性的塑料绝缘体而应用于电子工业也是早已得到公认。Harada及其在日立(Hitachi)中央研究实验室的同事曾就聚酰亚胺异吲哚喹唑啉二酮(简称PIQ)提出了报告。PIQ可用作大规模集成电路(LsI)多层布线的绝缘层及最后的钝化涂层。***和同事又报导了一种可以简化半导体工艺步骤的光敏聚

关键词：聚酞亚胺薄膜厚度表征热处理时间树脂杜邦

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Bulbocavernosus muscle area measurement： a novel method to assess androgenic activity

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Asian Journal of Andrology 2014年第4期16卷 618-622页

作者： Ali A Dabaja Matthew s Wosnitzer Anna Mielnik Alexander Bolyakov Peter N schlegel Darius A Paduch Department of Urology and Reproductive Medicine Weill Cornell Medical College New York USA.

serum testosterone does not correlate with androgen tissue activity, and it is critical to optimize tools to evaluate such activity in males. Ultrasound measurement of bulbocavernosus muscle （BCM） was used to assess the relationship between the number of CAG repeats （CAGn） in the androgen receptor （AR） and the BCM size; the changes in the number of CAGn over age were also evaluated. Transperineal ultrasound measurement of the BCM was also performed. AR CAGn were determined by high performance liquid chromatography, and morning hormone levels were determined using immunoassays. Forty-eight men had CAG repeat analysis. Twenty-five were 〈30 years of age, mean 23.7 years （s.d, = 3.24） and 23 were 〉45 years of age, mean 53years （s.d. = 5.58）. The median CAGn was 21 （13-29）. BCM area was greater when the number of CAGn were 〈18 as compared to the number of CAGn 〉24 （P= 0.04）. There was a linear correlation between the number of CAGn and the BCM area R^2= 16% （P= 0.01）. In the 45 to 65-years-old group, a much stronger negative correlation （R^2 = 29%, P= 0.01） was noticed. In the 19 to 29-years-old group, no such correlation was found （R2 = 4%, P = 0.36）. In older men, the number of CAGn increased with age （R^2 = 32%, P= 0.01）. The number of CAGn in the AR correlates with the area of the BCM. Ultrasound assessment of the BCM is an effective surrogate to evaluate end-organ activity of androgens. The number of CAGn may increase with age.

关键词： age androgen activity androgen receptor androgen sensitivity bulbocavernosus muscle CAG repeats

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Effect of Cereal Brans supplementation on Quality Characteristics of Various Indigenous Products

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Journal of Food science and Engineering 2011年第2期1卷 111-118页

作者： s. sharma H. P. s. Nagi B. singh K. Priya Department of Food science and Technology Punjab Agricultural University Ludhiana 141004 India

The effect of using different cereal brans （wheat, rice, oat and their combination） at different levels （0, 5, 10%） in different indigenous products （Balushahi, mathi, Kulcha and Paratha） on color, texture and sensory quality was studied. The addition of cereal bran decreased the ＂L＂ values and increased the ＂a＂ value of all the developed indigenous products. supplementation of different cereal bran had significant effect on texture of the developed indigenous products. Overall hardness of the products decreased with addition of cereal brans. Among various cereal bran levels used, 10% supplementation showed maximum hardness in all types of products. Cereal bran supplementation significantly improved the protein and fibre content of all indigenous products. On the basis of physical analysis and sensory attributes, it was concluded that cereal brans can be substituted upto 5% （rice bran and bran in combination） and 10% levels （wheat bran and oat bran） in whole wheat flour and maida for developing indigenous products without adversely affecting quality attributes.

关键词： Cereal brans balushahi mathi kulcha paratha supplementation quality.

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79&PARK住宅区

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城市环境设计 2019年第2期118卷 198-209页

作者： H?gni laksáfoss Agata Wozniczka Agne Tamasauskaite Alberto Herzog Borko Nikolic Christin svensson Claudio Moretti Dominic Black Eva seo-Andersen Frederik Wegener Gabrielle Nadeau Jacob Lykkefold Aaen Jaime Peiro suso Jan Magasanik Jesper Boye Andersen Jonas Aars? Larsen Julian Andres Ocampo salazar Karl Johan Nyqvist Karol Bogdan Borkowski Katarina Mácková Katrine Juul Kristoffer Negendahl Lucian Racovitan Maria Teresa Fernandez Rojo Max Gabriel Pinto Min Ter Lim Narisara Ladawal schr?der Romea Muryn Ryohei Koike sergiu Calacean song He Taylor McNally-Anderson Terrence Chew Thomas sebastian Krall Tiago sá Tobias Vall? s?rensen Tore Banke Laurian Ghinitoiu 朱翰林

位于G?rdet国家公园边缘,Kullen有意识地塑造了一个尊重且适应环境的形式,并展现出与众不同的社区和壮丽的景色。为直接回应周围环境,建筑的西北和东南角高起至临近周边的高度;而距离公园最远、且本是视野最不好的东北角被拉高以使其拥... 详细信息

位于G?rdet国家公园边缘,Kullen有意识地塑造了一个尊重且适应环境的形式,并展现出与众不同的社区和壮丽的景色。为直接回应周围环境,建筑的西北和东南角高起至临近周边的高度;而距离公园最远、且本是视野最不好的东北角被拉高以使其拥有公园和港口最壮阔的景色。建筑西南角延伸至最远处的G?rdet国家公园;为了在建筑和自然之间创造一个人性化的柔和边缘,西南角被尽可能地压低,变成

关键词：住宅区

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