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A descriptive study of the strategy-to-performance gap from a resource-based perspectiveNorval, William Henry 12 1900 (has links)
The purpose of this study was to determine which specific resources contribute to the strategy-to-performance gap of small businesses trading in the Pietermaritzburg metropolitan area, from a resource-based perspective of strategic management.
The research was prompted by a study conducted by Marakon Associates, the purpose of which was to investigate how successfully companies translate their strategies into performance and what steps they take to close the resulting strategy-to-performance gaps. The main reasons advanced for poor strategy-to-performance results are inadequate or unavailable resources.
The research design in the study is quantitative and descriptive in nature. The data was collected from a structured questionnaire comprising of 18 questions emailed to the owners using LimeSurvey.
The findings of the survey show that the businesses surveyed lack resources, which leads directly to strategy-to-performance gaps. The most important resources they lack are financial and human resources. / Business Management / M. Tech. (Business Administration)
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AN UNDERSTANDING OF MUSSEL ADHESION TO INFLUENCE MATERIALS DEVELOPMENTSamuel L Huntington (8983913) 12 October 2021 (has links)
<p>The development of new materials
has been inspired by lessons learned from natural systems. In the area of
underwater adhesion and adhesives, inspiration has come from the complex
protein adhesives generated by marine organism such as barnacle and mussels.
These protein systems have a high incorporation of a unique amino acid, dihydroxyphenylalanine,
and provides the unique adhesive qualities synthetic systems strive to emulate.</p>
<p>By understanding how marine mussels
stick to a variety of surfaces, new strategies can be explored for preventing
the adhesion of biological organisms to various substrates. A continuous
concern for marine vessels is the detrimental impact caused by biofouling on
the hull of the ship. Fuel consumption can increase as the vessel’s drag
increasing fuel consumption and non-native species can be introduced into new environments.
Taking inspiration from catechol curing, new oxidative surfaces were investigated
as potential antifouling coatings.</p>
<p>Further insight into the marine
mussels ability to apply and cure its adhesive on a variety of substrate has
also inspired various synthetic polymers. The catechol moiety can be
incorporated into a polymer backbone to give a new solvent based adhesive. Further
investigation of the poly(styrene-co-(3,4-dihydroxystyrene)) adhesive system was
done to formulate an underwater adhesive for unique use cases. A terpolymer was
also explored as an ideal adhesive taking inspiration from the mussels by
incorporating flexible, stiff, and sticky components to give a tunable adhesive.</p>
<p>Having a strong bonding synthetic
adhesive that can be used on a laboratory scale is good for academic
investigation, but not of use outside the lab if it cannot easily be produced
on a commercial scale. With the goal of large scale synthesis, a new
polymerization method was introduced addressing some of the issues currently preventing
commercial scale production.</p><br>
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Deformačně-napěťová analýza tenkostěnné skříně vystavené rázovému zatížení od výbuchu / Stress-strain analysis of the thin wall structure subjected to impact loadTatalák, Adam January 2016 (has links)
This master thesis deals with stress-strain analysis of simplified model of the thin wall transformer case subjected to impact load of electrical blast. Electrical blast is replaced by chemical blast (detonation of high explosive). The problem is solved using computational modeling utilizing the Finite Element Method (FEM) and LS-DYNA solver. After the introduction where detonation and shock wave propagation is explained the analytical approach is presented. This approach serves to results verification. In the next chapter is conducted research of applicable methods from which ALE method is chosen. In preliminary study is performed the mesh size analysis that is focused on finding the size of element which is both computational effective and gives accurate results. Next the infulence of input conditions (shape, location and parametres of high explosive, location of detonation point, boundary conditions) on distribution and time progress of pressure is investigated. Then influence of the opening on upper side of the case on overall pressure redistribution and strain and stress of the case is analysed. The stress-strain analysis of the case´s door which are connected to case by various types of contact models is performed as well as stiffness analysis of these types of contact.
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DISSOLUTION AND MEMBRANE MASS TRANSPORT OF SUPERSATURATING DRUG DELIVERY SYSTEMSSiddhi-Santosh Hate (8715135) 17 April 2020 (has links)
<p>Supersaturating drug delivery systems are an attractive solubility enabling formulation strategy for poorly soluble drugs due to their potential to significantly enhance solubility and hence, bioavailability. Compendial dissolution testing is commonly used a surrogate for assessing the bioavailability of enabling formulations. However, it increasingly fails to accurately predict <i>in vivo</i> performance due its closed-compartment characteristics and the lack of absorptive sink conditions. <i>In vivo</i>, drug is continually removed due to absorption across the gastrointestinal membrane, which impacts the luminal concentration profile, which in turn affects the dissolution kinetics of any undissolved material, as well as crystallization kinetics from supersaturated solutions. Thus, it is critical to develop an improved methodology that better mimics <i>in vivo</i> conditions. An enhanced approach integrates dissolution and absorption measurements. However, currently-used two-compartment absorptive apparatuses, employing a flat-sheet membrane are limited, in particular by the small membrane surface area that restricts the mass transfer, resulting in unrealistic experimental timeframes. This greatly impacts the suitability of such systems as a formulation development tool. The goal of this research is two-fold. First, to develop and test a high surface area, flow-through, absorptive dissolution testing apparatus, designed to provide <i>in vivo</i> relevant information about formulation performance in biologically relevant time frames. Second, to use this apparatus to obtain mechanistic insight into physical phenomenon occurring during formulation dissolution. Herein, the design and construction of a coupled dissolution-absorption apparatus using a hollow fiber membrane module to simulate the absorption process is described. The hollow fiber membrane offers a large membrane surface area, improving the mass transfer rates significantly. Following the development of a robust apparatus, its application as a formulation development tool was evaluated in subsequent studies. The dissolution-absorption studies were carried out for supersaturated solutions generated via anti-solvent addition, pH-shift and by dissolution of amorphous formulations. The research demonstrates the potential of the apparatus to capture subtle differences between formulations, providing insight into the role of physical processes such as supersaturation, crystallization kinetics and liquid-liquid phase separation on the absorption kinetics. The study also explores dissolution-absorption performance of amorphous solid dispersions (ASDs) and the influence of resultant solution phase behavior on the absorption profile. Residual crystalline content in ASDs is a great concern from a physical stability and dissolution performance perspective as it can promote secondary nucleation or seed crystal growth. Therefore, the risk of drug crystallization during dissolution of ASDs containing some residual crystals was assessed using absorptive dissolution measurements and compared to outcomes observed using closed-compartment dissolution testing. Mesoporous silica-based formulations are another type of amorphous formulations that are gaining increased interest due to higher physical stability and rapid release of the amorphous drug. However, their application may be limited by incomplete drug release resulting from the adsorption tendency of the drug onto the silica surface. Thus, the performance of mesoporous silica-based formulations was also evaluated in the absorptive dissolution testing apparatus to determine the impact of physiological conditions such as gastrointestinal pH and simultaneous membrane absorption on the adsorption kinetics during formulation dissolution. Overall, the aim of this research was to demonstrate the potential of the novel <i>in vitro</i> methodology and highlight the significance of a dynamic absorptive dissolution environment to enable better assessment of complex enabling formulations. <i>In vivo</i>, there are multiple physical processes occurring in the gastrointestinal lumen and the kinetics of these processes strongly depend on the absorption kinetics and <i>vice-a-versa</i>. Thus, using this novel tool, the interplay between solution phase behavior and the likely impacts on bioavailability of supersaturating drug delivery systems can be better elucidated. This approach and apparatus is anticipated to be of great utility to the pharmaceutical industry to make informed decisions with respect to formulation optimization.</p>
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Aplicación de herramientas del Lean Six Sigma para generar valor en proyectos de Pequeña Minería. Proyecto Trinidad / Application of Lean Six Sigma tools to generate value in Small Mining projects. Trinidad ProjectBazo Gonzales, Jose Leonardo, Loayza Chávez, Gerardo Manuel 02 January 2021 (has links)
En la presente tesis se estudia la aplicación de las herramientas del Lean Six Sigma en el desarrollo de una metodología para la evaluación de proyectos auríferos de vetas angostas en el norte del Perú. Dichas herramientas responden a controles de calidad, tiempo y procesos, los cuales tienen como finalidad el desarrollo de la evaluación económica del Proyecto Trinidad. La propuesta se desarrolló, en primer lugar, con un análisis inicial del proyecto Trinidad con la finalidad de generar estrategias, dicha actividad consta de tres partes: matriz inicial del proyecto, House of Quality y análisis FODA. En segundo lugar, se determinaron las mermas operativas y se diseñó el mapa de flujo de procesos mediante la herramienta BPM (Business Process Management). En tercer lugar, se estableció un control en los tiempos para los procesos identificados para la evaluación del proyecto, mediante la herramienta JIT (Just In Time), es aquí donde se determina los plazos para las actividades involucradas, desde gestión de información hasta cálculo de recursos, método y secuenciamiento de minado y determinación de costos. Finalmente, se analiza el valor del proyecto y el riesgo que conlleva su ejecución. Mediante indicadores como VAN y TIR calculados a partir de la identificación del CAPEX, OPEX y el flujo de caja obtenido del valor teórico de los recursos y los costos operativos. / This thesis studies the application of Lean Six Sigma tools in the development of a methodology for evaluating narrow vein gold projects in northern Peru. Such tools respond to quality, time and process controls, which are intended to develop the economic evaluation of the Trinidad Project. The proposal was developed, firstly, with an initial analysis of the Trinidad project in order to generate strategies, said activity consists of three parts: initial project matrix, House of Quality and SWOT analysis. Secondly, operational losses were determined and the process flow map was designed using the BPM (Business Process Management) tool. Third, a control was established in the times for the processes identified for the evaluation of the project, through the JIT (Just In Time) tool, it is here where the deadlines for the activities involved are determined, from information management to calculation of resources, mining method and sequencing and cost determination. Finally, the value of the project and the risk involved in its execution are analyzed. Through indicators such as NPV and IRR calculated from the identification of CAPEX, OPEX and the cash flow obtained from the theoretical value of resources and operating costs. / Tesis
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Numerical modeling of the surface and the bulk deformation in a small scale contact: application to the nanoindentation interpretation and to the micro-manipulationBerke, Peter 19 December 2008 (has links)
<p align='justify'>L’adaptation des surfaces pour des fonctions prédéterminées par le choix des matériaux métalliques ou des couches minces ayant des propriétés mécaniques avancées peut potentiellement permettre de réaliser des nouvelles applications à petites échelles. Concevoir de telles applications utilisant des nouveaux matériaux nécessite en premier lieu la connaissance des propriétés mécaniques des matériaux ciblés à l’échelle microscopique et nanoscopique. Une méthode souvent appliquée pour caractériser les matériaux à petites échelles est la nanoindentation, qui peut être vue comme une mesure de dureté à l’échelle nanoscopique.</p><p><p align='justify'>Ce travail présente une contribution relative à l'interprétation des résultats de la nanoindentation, qui fait intervenir un grand nombre de phénomènes physiques couplés à l'aide de simulations numériques. A cette fin une approche interdisciplinaire, adaptée aux phénomènes apparaissant à petites échelles, et située à l’intersection entre la physique, la mécanique et la science des matériaux a été utilisée. Des modèles numériques de la nanoindentation ont été conçus à l'échelle atomique (modèle discret) et à l'échelle des milieux continus (méthode des éléments finis), pour étudier le comportement du nickel pur. Ce matériau a été choisi pour ses propriétés mécaniques avancées, sa résistance à l'usure et sa bio-compatibilité, qui peuvent permettre des applications futures intéressantes à l'échelle nanoscopique, particulièrement dans le domaine biomédical. Des méthodes avancées de mécanique du solide ont été utilisées pour prendre en compte les grandes déformations locales du matériau (par la formulation corotationelle), et pour décrire les conditions de contact qui évoluent au cours de l'analyse dans le modèle à l'échelle des milieux continus (traitement des conditions de contact unilatérales et tangentielles par une forme de Lagrangien augmenté).</p><p><p align='justify'>L’application des modèles numériques a permis de contribuer à l’identification des phénomènes qui gouvernent la nanoindentation du nickel pur. Le comportement viscoplastique du nickel pur pendant nanoindentation a été identifié dans une étude expérimentale-numérique couplée, et l'effet cumulatif de la rugosité et du frottement sur la dispersion des résultats de la nanoindentation a été montré par une étude numérique (dont les résultats sont en accord avec des tendances expérimentales).</p> <p><p align='justify'>Par ailleurs, l’utilisation de l’outil numérique pour une autre application à petites échelles, la manipulation des objets par contact, a contribué à la compréhension de la variation de l’adhésion électrostatique pendant micromanipulation. La déformation plastique des aspérités de surface sur le bras de manipulateur (en nickel pur) a été identifiée comme une source potentielle d’augmentation importante de l'adhésion pendant la micromanipulation, qui peut potentiellement causer des problèmes de relâche et de précision de positionnement, observés expérimentalement.</p><p><p align='justify'>Les résultats présentés dans cette thèse montrent que des simulations numériques basées sur la physique du problème traité peuvent expliquer des tendances expérimentales et contribuer à la compréhension et l'interprétation d'essais couramment utilisé pour la caractérisation aux petites échelles. Le travail réalisé dans cette thèse s’inscrit dans un projet de recherche appelé "mini-micro-nano" (mµn), financé par la Communauté Française de Belgique dans le cadre de "l'Action de Recherche Concertée", convention 04/09-310.</p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished
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Anisotropic Viscoelasticity at Large Strain DeformationsSchmidt, Hansjörg 14 August 2018 (has links)
The aim of this thesis is the fast and exact simulation of modern materials like fibre reinforced thermoplastics and fibre reinforced elastomers. These simulations are in the scope of large strain deformations and contain anisotropic and viscoelastic behaviour. The chapter Differential geometry outlines the necessary tensor analysis and differential geometry. We present the weak formulation in the undeformed domain and use Newton’s method to approximate the solution of this formulation, cf. Section 3.1 and Chapter 4, respectively. For the viscoelasticity we use a special ansatz for the internal variable. Next, we compute all necessary derivations for the Newton system, cf. Sections 4.2 and 4.3. We also investigate the symmetry of the material tensors in Section 4.4. Further, we present three methods to improve the convergence of Newton’s method, cf. Section 4.5. With these three methods we are able to consider more problems, compute them faster and in a more robust way. In Chapter 5 we concisely discuss the FEM and show the appearing matrices in detail. The aim of Chapter 6 is the application of the a posteriori error estimator to this complex material behaviour. We present some numerical examples in Chapter 7. In Chapter 8 the problems that arise in the simulation of fibre-reinforced elastomers are analysed and tackled with help of mixed formulations. We derive a symmetric mixed formulation from a reduced form of the energy density. Also, we reformulate the mixed variable for inextensibility to avoid the numerical cancellation in Section 8.3. The Section 8.4 is about a joined mixed formulation to solve problems with inextensible fibres in an incompressible matrix, like fibre-reinforced rubber. The succeeding section Section 8.5 deals with the arising indefinite block matrix system.:Contents
Glossary 5
1 Introduction – motivation 13
2 Differential geometry 15
2.1 From parametrisations to the Lagrangian strain 15
2.2 Derivatives of tensors 20
3 Physical foundations 25
3.1 Large Deformation 25
3.1.1 Balance of forces 25
3.1.2 Energy minimisation 28
3.2 Anisotropic energy density 29
3.3 Viscoelasticity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
4 Newton’s method 37
4.1 Newton system 37
4.2 Anisotropic material tensor 40
4.3 Viscoelastic material tensor 41
4.4 Symmetry of the material tensor 44
4.5 Load steps and line-search 47
4.5.1 Load steps – time steps 47
4.5.2 Backtracking for det ℱ > 0 48
4.5.3 Line search for energy minimisation 49
5 Implementation 53
5.1 Numerical Integration 53
5.2 Finite element discretisation 54
5.3 Voigt notation 56
6 Mesh control 65
7 Numerical results 69
7.1 Semi-analytical example 69
7.2 Cook’s membrane 71
7.2.1 Viscoelastic example 72
7.3 Chemnitz hook – Chemnitzer Haken 72
8 Mixed formulation 75
8.1 Motivation 75
8.2 General considerations 78
8.3 Smooth square root 81
8.4 Joined mixed formulation 84
8.5 Matrix representation 86
9 Conclusion 91
10 Theses 93
11 Appendix 95
11.1 Derivatives of the distortion-invariants with respect to the pseudo invariants 95
Bibliography 101
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Some Initiatives in Calculus TeachingAbramovitz, Buma, Berezina, Miryam, Berman, Abraham, Shvartsman, Ludmila 10 April 2012 (has links)
In our experience of teaching Calculus to engineering undergraduates we have had to grapple
with many different problems. A major hurdle has been students’ inability to appreciate the
importance of the theory. In their view the theoretical part of mathematics is separate from the
computing part. In general, students also believe that they can pass their exams even though they
do not have a real understanding of the theory behind the problems they are required to solve. In
an effort to surmount these difficulties we tried to find ways to make students better understand
the theoretical part of Calculus. This paper describes our experience of teaching Calculus. It
reports on the continuation of our previous research.
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Development of a continuum model for ferrogelsAttaran, Abdolhamid, Brummund, Jörg, Wallmersperger, Thomas 25 October 2019 (has links)
A systematic development of a continuum model is presented, which is capable of describing the magneto-mechanical behavior of magnetic polymer gels commonly referred to as ‘‘ferrogels’’. In the present research, ferrogels are treated as multicomponent, multiphase materials. They consist of a polymer network (P), fixed magnetic particles (f), mobile magnetic particles (m), and liquid (L). By considering ferrogels as multicomponent materials, interaction among constituents of ferrogels can be captured. This helps in understanding the process occurring inside ferrogels under the influence of external stimuli, such as magnetic fields. In our modeling approach, the field equations of ferrogels are derived within the framework of the theory of mixtures. The basic equations include Maxwell’s equations, balance of mass, linear momentum, angular momentum, energy, and entropy. In the framework of the theory of mixtures, balance relations are first presented at the constituent level also referred to as partial balance relations. By summing partial balance relations over all constituents and imposing the restrictions of theory of mixtures, balance relations of mixture (for the ferrogel) are obtained. In the current work the specific magnetization (magnetization per density) is considered as an evolving variable. It is demonstrated that balance of angular momentum is satisfied using the evolution equation of specific magnetization and constitutive laws. In the process of modeling, a suitable free energy function is introduced and thermodynamically consistent constitutive laws are formulated. Introducing certain assumptions, a reduced model of the ferrogel, a coupled magneto-mechanical formulation, is subsequently presented. The reduced model consists only of a polymer network (P) and fixed magnetic particles (f). It is concluded that the reduced model compares well to the existing ones in the literature. The magneto-mechanical problem based on the reduced model is solved in 2D using the finite element method. The only unknowns for the finite element method implementation are mechanical displacement and magnetic potential. Deformation of a ferrogel in a magnetic field is subsequently investigated. Elongation and contraction of a ferrogel are observed when a magnetic field is applied in the x- and y-directions, respectively. The numerical results were compared with existing experimental work in the literature. A good qualitative agreement was found between numerical and experimental results.
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Transport und Relaxation in QuantenmodellenKadiroglu, Mehmet 08 December 2009 (has links)
Das Transport- und Relaxationsverhalten verschiedener Quantenmodelle wird untersucht. Den ersten Teil der vorliegenden Arbeit bildet die Untersuchung der Transporteigenschaften von speziellen finiten modularen Quantensystemen bzgl. einer Boltzmann-Gleichung (BG). Diese Systeme, in denen unter bestimmten Bedingungen diffusiver Transport beobachtet werden kann, wurden mit verschiedenen Methoden zur Beschreibung von Quantentransport untersucht. Dabei zeigt sich, dass sich das diffusive Transportverhalten in diesen Systemen aus der zugrunde liegenden Schrödinger Dynamik heraus beschreiben lässt. Ob die diffusive Dynamik in diesen Systemen ebenfalls auf der Basis einer BG beschrieben werden kann, wird analytisch und numerisch untersucht. Im zweiten Teil wird die Relaxationsdynamik in quantenmechanischen Vielteilchensystemen untersucht. Speziell wird versucht, die Lebensdauern von angeregten Elektronen (Löchern) in Metallen, welche mit dem Fermi-See der Elektronen wechselwirken, mittels der zeitfaltungsfreien Projektionsoperator-Methode (TCL) zu bestimmen. Letztere liefert einen analytischen Ausdruck für die Dämpfungsrate (inverse Lebensdauer), welche temperaturabhängig ist und im Rahmen von Standard-Streuprozessen interpretiert werden kann. Um dieses analytische Ergebnis zu testen, wird es angewendet, um die Lebensdauern angeregter Elektronen (Löcher) in Aluminium zu bestimmen, für das ein Jellium Modell verwendet wird. Die Ergebnisse, die man über Monte-Carlo-Integration erhält, werden mit experimentellen und theoretischen Daten aus Selbstenergie-Rechnungen verglichen. Des Weiteren werden die Lebensdauern angeregter Elektronen in Kupfer ermittelt, für das ein Tight-Binding-Modell verwendet wird.
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