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A Spin Network Generalization Of The Jones Polynomial And Vassiliev Invariants, Rodolfo Gambini, Jorge Griego, Jorge Pullin Apr 1998

A Spin Network Generalization Of The Jones Polynomial And Vassiliev Invariants, Rodolfo Gambini, Jorge Griego, Jorge Pullin

Faculty Publications

We apply the ideas of Alvarez and Labastida to the invariant of spin networks defined by Witten and Martin based on Chern-Simons theory. We show that it is possible to define ambient invariants of spin networks that (for the case of SU(2)) can be considered as extensions to spin networks of the Jones polynomial. Expansions of the coefficients of the polynomial yield primitive Vassiliev invariants. The resulting invariants are candidates for solutions of the Wheeler-DeWitt equations in the spin network representation of quantum gravity.© 1998 Elsevier Science B.V. All rights reserved.

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Mortality And Optimal Body Mass Index In A Sample Of The Us Population, Ramón A. Durazo-Arvizu, Daniel L. Mcgee, Richard S. Cooper, Youlian Liao, Amy Luke Apr 1998

Mortality And Optimal Body Mass Index In A Sample Of The Us Population, Ramón A. Durazo-Arvizu, Daniel L. Mcgee, Richard S. Cooper, Youlian Liao, Amy Luke

Faculty Publications

In this paper, the authors model the nonmonotonic relation between body mass index (BMI) (weight (kg)/height2 (m2)) and mortality in 13,242 black and white participants in the NHANES I Epidemiologic Follow-up Study in order to estimate the BMI at which minimum mortality occurs. The BMI of minimum mortality was 27.1 for black men (95% confidence interval (CI) 24.8-29.4), 26.8 for black women (95% CI 24.7-28.9) 24.8 for white men (95% CI 23.8- 25.9), and 24.3 for white women (95% CI 23.3-25.4). Each confidence interval included the group average. Analyses conducted by smoking status and after exclusion of persons with baseline …

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Sand Body Geometry Of The Wax Lake Outlet Delta Atchafalaya Bay, Louisiana, Susan Majersky Fitzgerald Mar 1998

Sand Body Geometry Of The Wax Lake Outlet Delta Atchafalaya Bay, Louisiana, Susan Majersky Fitzgerald

LSU Historical Dissertations and Theses

Deltas forming in Atchafalaya Bay, L-ouisiana, are the result of delta switching by the Mississippi River. The larger Lower Atchafalaya River delta has been heavily manipulated by dredging for navigation, but the Wax Lake Outlet delta is largely undisturbed and an excellent example of a 'bayhead' delta. Combining stratigraphy, aerial photography and digital terrain model data sets, the developmental history of this delta is presented. The Wax Lake Outlet delta is comprised of a typical upward-coarsening sequence, although its prodelta unit is extremely limited. Its plan-view form is typical of deltas developing in low-energy, unstratified, shallow basins. Early developmental processes …

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Extensions Of The Poisson Summation Formula, A. L. Durán, R. Estrada, R. P. Kanwal Feb 1998

Extensions Of The Poisson Summation Formula, A. L. Durán, R. Estrada, R. P. Kanwal

Faculty Publications

The classical Poisson summation formula (1.1) and the corresponding distributional formula (1.2) have found extensive applications in various scientific fields. However, they are not universally valid. For instance, if φ(x) is a smooth function, the left-hand side of (1.1) is generally divergent. Even when both sides of (1.1) converge absolutely, they may do so to different numbers. Indeed, in Example 3 we are faced with the embarrassing situation where the series on the left-hand side of (1.1) converges for Res1 while that on the right-hand side converges only for Res<0. Our aim is to extend formulas (1.1) and (1.2) with the help of some new results in distributional theory. For instance, the evaluation of the distribution with zero mean as given by (3.1) at a test function φ(x) yields the relation ∑∞-∞φ(k)-∫∞-∞φ(x)dx. Both the series and the integral in this expression are generally divergent. The concept of the Cesàro limit is then used to obtain the finite difference of these two terms. Thereafter we extend the analysis to higher dimensions. Various innovative examples are presented to illustrate these concepts. © 1998 Academic Press.

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Panelling Planar Graphs, James Oxley, Don Row Jan 1998

Panelling Planar Graphs, James Oxley, Don Row

Faculty Publications

The skeleton of a spherical polyhedron may also be viewed as the skeleton of other panelled structures. We characterize those collections of cycles of a planar graph that bound the panels of hinged-panel structures, and distinguish those that arise from spherical polyhedra.

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On The Value Functions Of Some Singular Optimal Control Problems., Jesus Alberto Pascal Jan 1998

On The Value Functions Of Some Singular Optimal Control Problems., Jesus Alberto Pascal

LSU Historical Dissertations and Theses

Infinite horizon singular optimal control problems with control taking values in a closed cone U in Rn lead to a dynamic programming equation of the form: maxF2x,v, v',v'' ,F1x,v,v' =0, forall x∈Q, where Q , the state space of the control problem, is some nonempty connected open subset of Rn , and F1, F2 are continuous real-valued functions on QxR2 and QxR3 respectively, with the coercivity assumption for F 2, that is, the function r&rarrr;F2x,u,p,r is nonincreasing on R . A major concern is to determine how smooth the value function v is across the free boundary of the problem. …

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Numerical Modeling Of Multi-Species Transport In Soils Under Electric Fields., Wenbing Zheng Jan 1998

Numerical Modeling Of Multi-Species Transport In Soils Under Electric Fields., Wenbing Zheng

LSU Historical Dissertations and Theses

A generalized mathematical model for electrokinetic soil processing is presented for multi-species transport of reactive components under electric fields in two-dimensional geometry, based on the earlier Acar-Alshawabkeh model. In this model, sets of partial differential equations are formulated for the transport of fluid, charge, and species in a saturated soil under coupled hydraulic, electrical, and chemical potentials. Chemical reactions pertaining to sorption, precipitation/dissolution, aqueous phase equilibria, water autoionization, and electrolysis are included in the new model. The boundary conditions corresponding to the mass transport equations are described. A program, EK-SIM (ElectroKinetic Soil Processing SIMulation), has been developed to simulate electrokinetic …

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A Knowledge-Based System For Reliability-Centered Maintenance In The Chemical Industry., Daniel Jesus Fonseca Jan 1998

A Knowledge-Based System For Reliability-Centered Maintenance In The Chemical Industry., Daniel Jesus Fonseca

LSU Historical Dissertations and Theses

An innovative new framework for the implementation of reliability centered maintenance (RCM) in industrial settings was developed and implemented during this study. Fuzzy reasoning algorithms were designed to evaluate and assess the likelihood of equipment failure mode precipitation and aggravation. Furthermore, an alternative to the traditional RCM decision tree for prioritizing equipment failure modes was defined through the development of an approximate reasoning scheme. This priority scheme not only takes into account the relevancy of failure modes on local and product effects, but also their possibility of occurrence, as well as associated negative consequences on adjacent machinery. The new RCM …

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Analysis Of Taper-Taper Adhesive-Bonded Joints In Composite Plates Under Tension And Cylindrical Bending., Jack Elwin Helms Jr Jan 1998

Analysis Of Taper-Taper Adhesive-Bonded Joints In Composite Plates Under Tension And Cylindrical Bending., Jack Elwin Helms Jr

LSU Historical Dissertations and Theses

A taper-taper adhesive-bonded joint between two composite plates has been analyzed under tension and cylindrical bending. Two tension models were derived. The first model was based on mechanics of materials and the second model used laminated plate theory and shear correction factors. For the mechanics of materials model the condition of plane strain was assumed for the adherends and adhesive. Average stresses were used in the adherends and point-wise stresses were used in the adhesive. The model derived consisted of four second-order ordinary differential equations with variable coefficients. The adherends were characterized by the extensional Young's modulus. The equations were …

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Physical And Chemical Properties Of Fibers Extracted From Sugarcane And Kenaf Rind., Simona Cristina Romanoschi Jan 1998

Physical And Chemical Properties Of Fibers Extracted From Sugarcane And Kenaf Rind., Simona Cristina Romanoschi

LSU Historical Dissertations and Theses

Sugar cane fibers were extracted from the rind of cane stalks with sodium hydroxide (NaOH) solutions of different concentrations, at atmospheric pressure, followed by a steam explosion. The extraction process was optimized using a central rotatable composite design, to study the influence of three reaction parameters (alkaline concentration, time of reaction and frequency of tumbling) on fiber bundle properties (weight, length, and tex). Tex was the objective function, with length as a constraint. Regression analysis indicated a quadratic polynomial response. Bleaching studies were conducted on sugar cane fibers extracted with 1.0N NaOH and on kenaf fibers mechanically processed only. Hydrogen …

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Considering Outcomes Beyond Achievement: Student Participation As An Indicator Of High School Performance., Susan Elizabeth Kochan-Teddlie Jan 1998

Considering Outcomes Beyond Achievement: Student Participation As An Indicator Of High School Performance., Susan Elizabeth Kochan-Teddlie

LSU Historical Dissertations and Theses

This dissertation is the product of a three-phase exploratory study that utilized both quantitative and qualitative methods in order to develop and test a composite indicator of high school performance that measures the degree to which high schools strike a balance between the press for academic excellence and the need to sustain all students--even the most marginal--on to high school completion. In Phase I, undaunted and relative performance indicators (UPIs and RPIs) of student achievement and participation were calculated for a statewide sample of 308 schools whose grade configurations included grades 9-12. The achievement scores were composites of student performance …

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Multilocation Inventory Systems With Centralized Information., Jianxin Hu Jan 1998

Multilocation Inventory Systems With Centralized Information., Jianxin Hu

LSU Historical Dissertations and Theses

The management of multi-echelon inventory systems has been both an important and challenging research area for many years. The rapid advance in information technology and the emphasis on integrated supply chain management have new implications for the successful operation of distribution systems. This research focuses on the study of some fundamental issues related to the operation of a multilocation inventory system with centralized information. First, we do a comparative analysis to evaluate the overall performance of individual versus centralized ordering policies for a multi-store distribution system where centralized information is available. This study integrates the existing research and clarifies one …

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Directed Search In K-System Reconstruction., Christopher W. Branton Jan 1998

Directed Search In K-System Reconstruction., Christopher W. Branton

LSU Historical Dissertations and Theses

K-systems analysis is a factor analysis technique created through the generalization of key reconstructability analysis definitions and algorithms. The method is applied to functions on systems of discrete variables to discover a set of factors which can explain the bulk of the function's variation from the mean. K-systems analysis uses principles of information theory to reveal interactions which are often masked by the assumptions implicit in traditional methods. The method has been used successfully to analyze systems in several disciplines. Despite the success of k-systems analysis, obstacles to the creation of a mature methodology still exist. Some issues and open …

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Three-Dimensional Parallel Finite Element Simulation Of Natural Gas Flow In A Porous Media., James David Callahan Jan 1998

Three-Dimensional Parallel Finite Element Simulation Of Natural Gas Flow In A Porous Media., James David Callahan

LSU Historical Dissertations and Theses

A parallel-three-dimensional finite element simulation of natural gas flow in a porous media was developed for use in multiple well reservoirs. Developed with this simulation was a set of graphical applications to provide a geometric description of the reservoir, viewing of the generated mesh and viewing of results generated by the simulation. An adaptive mesh scheme for the dynamic refinement and derefinement of the mesh during the solution process is presented. The adaptive mesh scheme utilizes a mesh storage technique designed to reduce the space requirements of the mesh. This adaptive mesh technique was applied to an unstructured mesh. A …

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Nanostructure Modeling In Oxide Ceramics Using Large Scale Parallel Molecular Dynamics Simulations., Timothy J. Campbell Jan 1998

Nanostructure Modeling In Oxide Ceramics Using Large Scale Parallel Molecular Dynamics Simulations., Timothy J. Campbell

LSU Historical Dissertations and Theses

The purpose of this dissertation is to investigate the properties and processes in nanostructured oxide ceramics using molecular-dynamics (MD) simulations. These simulations are based on realistic interatomic potentials and require scalable and portable multiresolution algorithms implemented on parallel computers. The dynamics of oxidation of aluminum nanoclusters is studied with a MD scheme that can simultaneously treat metallic and oxide systems. Dynamic charge transfer between anions and cations which gives rise to a compute-intensive Coulomb interaction, is treated by the O(N) Fast Multipole Method. Structural and dynamical correlations and local stresses reveal significant charge transfer and stress variations which cause rapid …

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Subterranean Echoes: Curriculum Theory As Cultural Studies., Toby Allan Daspit Jan 1998

Subterranean Echoes: Curriculum Theory As Cultural Studies., Toby Allan Daspit

LSU Historical Dissertations and Theses

Cultural studies has emerged in recent decades as a popular realm of academic inquiry (During, 1993). Giroux (1994), while noting the field's increased acceptance, ponders why cultural studies has yet to permeate critical analyses of education and simultaneously questions cultural studies' reticence in considering schools as an important site of cultural production. Edgerton (1996) concurs with Giroux and notes that cultural studies' use in colleges of education is extremely rare. The realm of popular culture, one of the central foci of cultural studies, has especially been marginalized in academic discourses. My project is to explore the implications of curriculum theory …

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Assessing The Reuse Potential Of Objects., Maria Lorna Reyes Jan 1998

Assessing The Reuse Potential Of Objects., Maria Lorna Reyes

LSU Historical Dissertations and Theses

In this research, we investigate whether reusable classes can be characterized by object-oriented (OO) software metrics. Three class-level reuse measures for the OO paradigm are defined: inheritance-based reuse, inter-application reuse by extension, and inter-application reuse as a server. Using data from a software company, we collected metrics on Smalltalk classes. Among the 20 metrics collected are cyclomatic complexity, Lorenz complexity, lines of code, class coupling, reuse ratio, specialization ratio and number of direct subclasses. We used stepwise regression to derive prediction models incorporating the 20 metrics as the independent variables and the reuse measures, applied separately, as the dependent variable. …

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Pseudo Power Signatures For Nonstationary Signal Analysis And Classification., Vidya Venkatachalam Jan 1998

Pseudo Power Signatures For Nonstationary Signal Analysis And Classification., Vidya Venkatachalam

LSU Historical Dissertations and Theses

This research focuses on the analysis and classification of multicomponent non-stationary signals of arbitrary duration. The proposed classification approach has potential applications in areas like moving target detection, object recognition, oil exploration, and speech processing. The wavelet transform is used as the basis for the analysis. The classification technique is based on novel scale energy density functions, called pseudo power signatures , which are independent of signal length, and which can be used to characterize the time-scale energy distribution of the signal. These signatures allow for fast classification of signals regardless of their length. Two approaches to determine pseudo power …

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Diversity Within Streptomyces Ipomoeae Based On Inhibitory Interactions, Rep-Pcr, And Plasmid Profiles, C. A. Clark, C. Chen, N. Ward-Rainey, G. S. Pettis Jan 1998

Diversity Within Streptomyces Ipomoeae Based On Inhibitory Interactions, Rep-Pcr, And Plasmid Profiles, C. A. Clark, C. Chen, N. Ward-Rainey, G. S. Pettis

Faculty Publications

Streptomyces soil rot is a destructive disease of sweetpotato (Ipomoea batatas) that causes yield loss resulting from decay of the feeder root system and reduced quality due to the presence of necrotic lesions on the storage roots. It is managed by the use of resistant cultivars, but variability of the pathogen has not been previously assessed. This study compared 36 strains of the pathogen Streptomyces ipomoeae from different locations in the United States and Japan. The strains could be separated into three groups on the basis of their ability to inhibit the growth of one another in in vitro assays. …

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Performance And Metabolic Responses Of Young Dairy Calves Fed Diets Supplemented With Chromium Tripicolinate, C. L. Depew, L. D. Bunting, J. M. Fernandez, D. L. Thompson, R. W. Adkinson Jan 1998

Performance And Metabolic Responses Of Young Dairy Calves Fed Diets Supplemented With Chromium Tripicolinate, C. L. Depew, L. D. Bunting, J. M. Fernandez, D. L. Thompson, R. W. Adkinson

Faculty Publications

Forty-two Holstein calves were used to study performance and metabolic responses when milk replacer and then postweaning starter were supplemented with 1 ppm of Cr as Cr-tripicolinate. From birth through 8 wk of age, supplemental Cr tended to improve the growth performance of bull calves but not of heifer calves. Starter intake and feed efficiency were not affected by supplemental Cr. From 1 to 5 wk of age, plasma cortisol concentrations sampled just prior to feeding decreased, and concentrations of insulinlike growth factor-I increased. All calves appeared to become less sensitive to insulin as they aged. From 1 to 5 …

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Characterization And Analysis Of The Superabrasive Diamond Blade Sawing Process., Harlan Dwayne Jerro Jan 1998

Characterization And Analysis Of The Superabrasive Diamond Blade Sawing Process., Harlan Dwayne Jerro

LSU Historical Dissertations and Theses

Diamond-impregnated segmented circular blade sawing is one of the most effective, versatile, and extensively used methods of processing rock and other hard materials, such as granite, marble, concrete and asphalt. For many years, it has been known that chip thickness is one of the most significant parameters in the understanding of the sawing process, and other variables such as force and power have been correlated with it. In this work, the material chipping geometries have been mathematically defined and derived through kinematics analysis. From these chipping geometries, chip area and thickness relations have been obtained. A relation for the mean …

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Development And Assessment Of A Property Rights-Based Measure Of State Regulatory Climate., Ferdinand Francis Wirth Iii Jan 1998

Development And Assessment Of A Property Rights-Based Measure Of State Regulatory Climate., Ferdinand Francis Wirth Iii

LSU Historical Dissertations and Theses

States implement many of the environmental laws enacted during the last thirty years. A key policy issue is the effect of differences in state institutions and environmental policies on the location of livestock agriculture. There is widespread belief that the stringency of state environmental regulations, known as regulatory climate, is an important factor influencing the location, growth and expansion decisions of livestock agriculture. Existing regulatory climate measures are not tailored to agriculture, and their use has given mixed results. Conceptual and empirical models were developed for the U.S. aquaculture industry, based on elements of public choice and firm location theories …

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Antiferromagnetic Hedgehogs With Superconducting Cores, Paul M. Goldbart, Daniel E. Sheehy Jan 1998

Antiferromagnetic Hedgehogs With Superconducting Cores, Paul M. Goldbart, Daniel E. Sheehy

Faculty Publications

Excitations of the antiferromagnetic state that resemble antiferromagnetic hedgehogs at large distances but are predominantly superconducting inside a core region are discussed within the context of Zhang’s SO(5)-symmetry-based approach to the physics of high-temperature superconducting materials. Nonsingular, in contrast with their hedgehog cousins in pure antiferromagnetism, these texture excitations are what hedgehogs become when the antiferromagnetic order parameter is permitted to “escape” into superconducting directions. The structure of such excitations is determined in a simple setting, and a number of their experimental implications are examined. © 1998 The American Physical Society.

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Single-Head Spin Modes In Frontal Polymerization, Victor M. Ilyashenko, John A. Pojman Jan 1998

Single-Head Spin Modes In Frontal Polymerization, Victor M. Ilyashenko, John A. Pojman

Faculty Publications

The single-head spin mode is the first two-dimensional pattern of self-propagating thermal reaction fronts observed after the planar front loses stability. A "hot spot" is observed to propagate around the periphery of the front. The dynamics of the single-head frontal polymerization regime were studied experimentally, and two novel results were found. The "hot spot" was measured and found to be superadiabatic. The relationship between the rotational velocity and the propagating velocity was found. Experimental data were also compared with the theoretical results based on the linear stability analysis and found to be in a reasonable agreement. © 1998 American Institute …

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The Effect Of Convection On A Propagating Front With A Liquid Product: Comparison Of Theory And Experiments, B. Mccaughey, J. A. Pojman, C. Simmons, V. A. Volpert Jan 1998

The Effect Of Convection On A Propagating Front With A Liquid Product: Comparison Of Theory And Experiments, B. Mccaughey, J. A. Pojman, C. Simmons, V. A. Volpert

Faculty Publications

This work is devoted to the investigation of propagating polymerization fronts converting a liquid monomer into a liquid polymer. We consider a simplified mathematical model which consists of the heat equation and equation for the depth of conversion for one-step chemical reaction and of the Navier-Stokes equations under the Boussinesq approximation. We fulfill the linear stability analysis of the stationary propagating front and find conditions of convective and thermal instabilities. We show that convection can occur not only for ascending fronts but also for descending fronts. Though in the latter case the exothermic chemical reaction heats the cold monomer from …

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Accelerated Degradation Tests: Modeling And Analysis, William Q. Meeker, Luis A. Escobar, C. Joseph Lu Jan 1998

Accelerated Degradation Tests: Modeling And Analysis, William Q. Meeker, Luis A. Escobar, C. Joseph Lu

Faculty Publications

High reliability systems generally require individual system components having extremely high reliability over long periods of time. Short product development times require reliability tests to be conducted with severe time constraints. Frequently few or no failures occur during such tests, even with acceleration. Thus, it is difficult to assess reliability with traditional life tests that record only failure times. For some components, degradation measures can be taken over time. A relationship between component failure and amount of degradation makes it possible to use degradation models and data to make inferences and predictions about a failure-time distribution. This article describes degradation …

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Computation On Metric Spaces Via Domain Theory, Jimmie Lawson Jan 1998

Computation On Metric Spaces Via Domain Theory, Jimmie Lawson

Faculty Publications

The purpose of this paper is to survey recent approaches to realizing (or embedding) a Polish space as the set of maximal points of a continuous domain. Such realizations provide a convenient framework in which to model certain computational algorithms on the space and a useful alternate approach via the probabilistic power domain to measure theory and integraion on the space. © 1998 Elsevier Science B.V.

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Heat Conduction In Fine Scale Mixtures With Interfacial Contact Resistance, Robert Lipton Jan 1998

Heat Conduction In Fine Scale Mixtures With Interfacial Contact Resistance, Robert Lipton

Faculty Publications

Heat conduction in a fine scale mixture of two conductors is examined in the presence of a contact resistance between phases. The problem is studied rigorously in the context of periodic homogenization. Unlike the case of perfect heat transmission between phases, the temperature gradients converge weakly as Radon measures. The strict ellipticity of the homogenized transport equation depends upon the geometry of the interface. The effective conductivity associated with the overall heat dissipation rate inside a composite cube is considered. It is shown that this property exhibits a size effect under rescaling.

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The Second Stekloff Eigenvalue And Energy Dissipation Inequalities For Functionals With Surface Energy, Robert Lipton Jan 1998

The Second Stekloff Eigenvalue And Energy Dissipation Inequalities For Functionals With Surface Energy, Robert Lipton

Faculty Publications

A functional with both bulk and interfacial surface energy is considered. It corresponds to the energy dissipated inside a two-phase electrical conductor in the presence of an electrical contact resistance at the two-phase interface. The effect of embedding a highly conducting particle into a matrix of lesser conductivity is investigated. We find the criterion that determines when the increase in surface energy matches or exceeds the reduction in bulk energy associated with the particle. This criterion is general and applies to any particle with Lipschitz continuous boundary. It is given in terms of the of the second Stekloff eigenvalue of …

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Influence Of Interfacial Surface Conduction On The Dc Electrical Conductivity Of Particle Reinforced Composites, Robert Lipton Jan 1998

Influence Of Interfacial Surface Conduction On The Dc Electrical Conductivity Of Particle Reinforced Composites, Robert Lipton

Faculty Publications

We describe new effects associated with electrical conduction along phase interfaces for particle reinforced conductors. For particles of general shape we introduce a new quantity β1 called the 'surface to volume dissipation' of a particle. This quantity is a measure of the particle's ability to dissipate energy on its surface relative to the energy dissipated in its interior. It is described mathematically as the minimum value of a suitably defined Rayleigh quotient and is related to an eigenvalue problem posed on the particle surface. We consider the overall conductivity of a particle reinforced conductor when the particle conductivities are less …

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