The goal of this method is to implement the volume and mass conserving characteristic method. This method is appropriate to the equation with advections and diffusions. Characteristic mixed FEM with piecewise constant approximation is applied to the advection part, and the diffusion part is handled by FDM.

Im Rahmen der vorliegenden Arbeit wurde eine retrospektive Analyse aller in der Frauenklinik des Klinikums Obergöltzsch in den Jahren zwischen 1993-2012 operierten Frauen mit der Erstdiagnose eines Mammakarzinoms vorgenommen. Dazu wurden 4462 Fälle hinsichtlich der operativen Versorgung ausgewertet. Zur besseren Vergleichbarkeit erfolgte die Einordnung in das Klassifikationssystem von Hoffmann und Wallwiener. Weiterhin erfolgte eine detaillierte Analyse einer 5 Jahres Kohorte ( 2003- 2007 ) hinsichtlich der Alters- und Stadienverteilung, der Rate an R 1- Resektionen, der Rate an Lokalrezidiven , der Wundheilungsstörungen und der ästhetischen Ergebnisse. Dabei wurde ein Überblick über das operative Spektrum der Frauenklinik des Klinikums Obergöltzsch aufgezeigt und die Qualität der Versorgung belegt.

A generally accepted goal in orthopaedic surgery today is to maximize conservation of tissue and reduce tissue damage. Bone-conserving implants have bone-mating surfaces that reproduce the natural curvature of bone structures, requiring less bone removal. No small, reliable, inexpensive and universal bone sculpting technique currently exists, however, that can both create and accurately align such complex surfaces. The goal of this thesis was to develop a haptic hard surface emulation mechanism that could be applied to curvilinear bone sculpting using a surgical robot. A novel dynamic physical constraint concept was developed that is able to emulate realistic hard constraints, smooth surface following, and realistic surface rigidity, while allowing complete freedom of motion away from the constraints. The concept was verified through the construction of a two-link manipulator prototype. Tests were run on nine users that involved each user tracing out five different virtual surfaces on a drawing surface using the prototype. The primary purposes of prototype testing were to obtain subjective data on how effectively the dynamic physical constraint concept simulates simple surfaces, to assess how it reacts to typical user interactions and to identify any unexpected behaviour. Users were 100% satisfied with the prototype’s ability to emulate realistic and stiff hard surfaces and with its ease of manipulation. The amount of incursion into each of the virtual surfaces by all the users was measured to assess the precision of the system with the goal of deciding whether this new haptic concept should be further developed specifically for precision applications such as surgery. For curvilinear surfaces, 90% of the cumulative distribution of the measured data was less than 2mm, while for linear surfaces it was less than 6mm. Four behavioural effects were noticed: lateral deflection, reverse ‘stickiness’, hysteresis and instability in certain areas. These effects were studied in detail to determine how to either eliminate them or to minimize them through system design optimization. A computer simulation was also used to model the behaviour of the prototype and to gain further understanding of these effects. These analyses showed that the concept can be successfully used in curvilinear bone sculpting.

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A generally accepted goal in orthopaedic surgery today is to maximize conservation of tissue and reduce tissue damage. Bone-conserving implants have bone-mating surfaces that reproduce the natural curvature of bone structures, requiring less bone removal. No small, reliable, inexpensive and universal bone sculpting technique currently exists, however, that can both create and accurately align such complex surfaces. The goal of this thesis was to develop a haptic hard surface emulation mechanism that could be applied to curvilinear bone sculpting using a surgical robot. A novel dynamic physical constraint concept was developed that is able to emulate realistic hard constraints, smooth surface following, and realistic surface rigidity, while allowing complete freedom of motion away from the constraints. The concept was verified through the construction of a two-link manipulator prototype. Tests were run on nine users that involved each user tracing out five different virtual surfaces on a drawing surface using the prototype. The primary purposes of prototype testing were to obtain subjective data on how effectively the dynamic physical constraint concept simulates simple surfaces, to assess how it reacts to typical user interactions and to identify any unexpected behaviour. Users were 100% satisfied with the prototype’s ability to emulate realistic and stiff hard surfaces and with its ease of manipulation. The amount of incursion into each of the virtual surfaces by all the users was measured to assess the precision of the system with the goal of deciding whether this new haptic concept should be further developed specifically for precision applications such as surgery. For curvilinear surfaces, 90% of the cumulative distribution of the measured data was less than 2mm, while for linear surfaces it was less than 6mm. Four behavioural effects were noticed: lateral deflection, reverse ‘stickiness’, hysteresis and instability in certain areas. These effects were studied in detail to determine how to either eliminate them or to minimize them through system design optimization. A computer simulation was also used to model the behaviour of the prototype and to gain further understanding of these effects. These analyses showed that the concept can be successfully used in curvilinear bone sculpting.

A generally accepted goal in orthopaedic surgery today is to maximize conservation of tissue and reduce tissue damage. Bone-conserving implants have bone-mating surfaces that reproduce the natural curvature of bone structures, requiring less bone removal. No small, reliable, inexpensive and universal bone sculpting technique currently exists, however, that can both create and accurately align such complex surfaces. The goal of this thesis was to develop a haptic hard surface emulation mechanism that could be applied to curvilinear bone sculpting using a surgical robot. A novel dynamic physical constraint concept was developed that is able to emulate realistic hard constraints, smooth surface following, and realistic surface rigidity, while allowing complete freedom of motion away from the constraints. The concept was verified through the construction of a two-link manipulator prototype. Tests were run on nine users that involved each user tracing out five different virtual surfaces on a drawing surface using the prototype. The primary purposes of prototype testing were to obtain subjective data on how effectively the dynamic physical constraint concept simulates simple surfaces, to assess how it reacts to typical user interactions and to identify any unexpected behaviour. Users were 100% satisfied with the prototype’s ability to emulate realistic and stiff hard surfaces and with its ease of manipulation. The amount of incursion into each of the virtual surfaces by all the users was measured to assess the precision of the system with the goal of deciding whether this new haptic concept should be further developed specifically for precision applications such as surgery. For curvilinear surfaces, 90% of the cumulative distribution of the measured data was less than 2mm, while for linear surfaces it was less than 6mm. Four behavioural effects were noticed: lateral deflection, reverse ‘stickiness’, hysteresis and instability in certain areas. These effects were studied in detail to determine how to either eliminate them or to minimize them through system design optimization. A computer simulation was also used to model the behaviour of the prototype and to gain further understanding of these effects. These analyses showed that the concept can be successfully used in curvilinear bone sculpting. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

Im Rahmen der vorliegenden Arbeit wurde eine retrospektive Analyse aller in der Frauenklinik des Klinikums Obergöltzsch in den Jahren zwischen 1993-2012 operierten Frauen mit der Erstdiagnose eines Mammakarzinoms vorgenommen. Dazu wurden 4462 Fälle hinsichtlich der operativen Versorgung ausgewertet. Zur besseren Vergleichbarkeit erfolgte die Einordnung in das Klassifikationssystem von Hoffmann und Wallwiener. Weiterhin erfolgte eine detaillierte Analyse einer 5 Jahres Kohorte ( 2003- 2007 ) hinsichtlich der Alters- und Stadienverteilung, der Rate an R 1- Resektionen, der Rate an Lokalrezidiven , der Wundheilungsstörungen und der ästhetischen Ergebnisse. Dabei wurde ein Überblick über das operative Spektrum der Frauenklinik des Klinikums Obergöltzsch aufgezeigt und die Qualität der Versorgung belegt.

Yes / Reverse Osmosis (RO) has already proved its worth as an efficient treatment method in chemical and environmental engineering applications. Various successful RO attempts for the rejection of organic and highly toxic pollutants from wastewater can be found in the literature over the last decade. Dimethylphenol is classified as a high-toxic organic compound found ubiquitously in wastewater. It poses a real threat to humans and the environment even at low concentration. In this paper, a model based framework was developed for the simulation and optimisation of RO process for the removal of dimethylphenol from wastewater. We incorporated our earlier developed and validated process model into the Species Conserving Genetic Algorithm (SCGA) based optimisation framework to optimise the design and operational parameters of the process. To provide a deeper insight of the process to the readers, the influences of membrane design parameters on dimethylphenol rejection, water recovery rate and the level of specific energy consumption of the process for two different sets of operating conditions are presented first which were achieved via simulation. The membrane parameters taken into consideration include membrane length, width and feed channel height. Finally, a multi-objective function is presented to optimise the membrane design parameters, dimethylphenol rejection and required energy consumption. Simulation results affirmed insignificant and significant impacts of membrane length and width on dimethylphenol rejection and specific energy consumption, respectively. However, these performance indicators are negatively influenced due to increasing the feed channel height. On the other hand, optimisation results generated an optimum removal of dimethylphenol at reduced specific energy consumption for a wide sets of inlet conditions. More importantly, the dimethylphenol rejection increased by around 2.51% to 98.72% compared to ordinary RO module measurements with a saving of around 20.6% of specific energy consumption.

Yes / Reverse Osmosis (RO) has already proved its worth as an efficient treatment method in chemical and environmental engineering applications. Various successful RO attempts for the rejection of organic and highly toxic pollutants from wastewater can be found in the literature over the last decade. Dimethylphenol is classified as a high-toxic organic compound found ubiquitously in wastewater. It poses a real threat to humans and the environment even at low concentration. In this paper, a model based framework was developed for the simulation and optimisation of RO process for the removal of dimethylphenol from wastewater. We incorporated our earlier developed and validated process model into the Species Conserving Genetic Algorithm (SCGA) based optimisation framework to optimise the design and operational parameters of the process. To provide a deeper insight of the process to the readers, the influences of membrane design parameters on dimethylphenol rejection, water recovery rate and the level of specific energy consumption of the process for two different sets of operating conditions are presented first which were achieved via simulation. The membrane parameters taken into consideration include membrane length, width and feed channel height. Finally, a multi-objective function is presented to optimise the membrane design parameters, dimethylphenol rejection and required energy consumption. Simulation results affirmed insignificant and significant impacts of membrane length and width on dimethylphenol rejection and specific energy consumption, respectively. However, these performance indicators are negatively influenced due to increasing the feed channel height. On the other hand, optimisation results generated an optimum removal of dimethylphenol at reduced specific energy consumption for a wide sets of inlet conditions. More importantly, the dimethylphenol rejection increased by around 2.51% to 98.72% compared to ordinary RO module measurements with a saving of around 20.6% of specific energy consumption.

The analysis of wave propagation in hyperelastic waveguides has significant applications in various branches of engineering like Non-Destructive Testing and Evaluation, impact analysis, material characterization and damage detection. Linear elastic models are typically used for wave analysis since they are sufficient for many applications. However, certain solids exhibit inherent nonlinear material properties that cannot be adequately described with linear models. In the presence of large deformations, geometric nonlinearity also needs to be incorporated in the analysis. These two forms of nonlinearity can have significant consequences on the propagation of stress waves in solids. A detailed analysis of nonlinear wave propagation in solids is thus necessary for a proper understanding of these phenomena. The current research focuses on the development of novel algorithms for nonlinear finite element analysis of stress wave propagation in hyperelastic waveguides. A full three-dimensional(3D) finite element analysis of stress wave propagation in waveguides is both computationally difficult and expensive, especially in the presence of nonlinearities. By definition, waveguides are solids with special geometric features that channel the propagation of stress waves along certain preferred directions. This suggests the use of kinematic waveguide models that take advantage of the special geometric features of the waveguide. The primary advantage of using waveguide models is the reduction of the problem dimension and hence the associated computational cost. Elementary waveguide models like the Euler-Bernoulli beam model, Kirchoff plate model etc., which are developed primarily within the context of linear elasticity, need to be modified appropriately in the presence of material/geometric nonlinearities and/or loads with high frequency content. This modification, besides being non-trivial, may be inadequate for studying nonlinear wave propagation and higher order waveguide models need to be developed. However, higher order models are difficult to formulate and typically have complex governing equations for the kinematic modes. This reflects in the relatively scarce research on the development of higher order waveguide models for studying nonlinear wave propagation. The formulation is difficult primarily because of the complexity of both the governing equations and their linearization, which is required as part of a nonlinear finite element analysis. One of the primary contributions of this thesis is the development and implementation of a general, flexible and efficient framework for automating the finite element analysis of higher order kinematic models for nonlinear waveguides. A hierarchic set of higher order waveguide models that are compatible with this formulation are proposed for this purpose. This hierarchic series of waveguide models are similar in form to the kinematic assumptions associated with standard waveguide models, but are different in the sense that no conditions related to the stress distribution specific to a waveguide are imposed since that is automatically handled by the proposed algorithm. The automation of the finite element analysis is accomplished with a dexterous combination of a nodal degrees-of-freedom based assembly algorithm, automatic differentiation and a novel procedure for numerically computing the finite element matrices directly from a given waveguide model. The algorithm, however, is quite general and is also developed for studying nonlinear plane stress configurations and inhomogeneous structures that require a coupling of continuum and waveguide elements. Significant features of the algorithm are the automatic numerical derivation of the finite element matrices for both linear and nonlinear problems, especially in the context of nonlinear plane stress and higher order waveguide models, without requiring an explicit derivation of their algebraic forms, automatic assembly of finite element matrices and the automatic handling of natural boundary conditions. Full geometric nonlinearity and the hyperelastic form of material nonlinearity are considered in this thesis. The procedures developed here are however quite general and can be extended for other types of material nonlinearities. Throughout this thesis, It is assumed that the solids under investigation are homogeneous and isotropic. The subject matter of the research is developed in four stages: First, a comparison of different finite element discretization schemes is carried out using a simple rod model to choose the most efficient computational scheme to study nonlinear wave propagation. As part of this, the frequency domain Fourier spectral finite element method is extended for a special class of weakly nonlinear problems. Based on this comparative study, the Legendre spectral element method is identified as the most efficient computational tool. The efficiency of the Legendre spectral element is also illustrated in the context of a nonlinear Timoshenko beam model. Since the spectral element method is a special case of the standard nonlinear finite element Method, differing primarily in the choice of the element basis functions and quadrature rules, the automation of the standard nonlinear finite element method is undertaken next. The automatic finite element formulation and assembly algorithm that constitutes the most significant contribution of this thesis is developed as an efficient numerical alternative to study the physics of wave propagation in nonlinear higher order structural models. The development of this algorithm and its extension to a general automatic framework for studying a large class of problems in nonlinear solid mechanics forms the second part of this research. Of special importance are the automatic handling of nonlinear plane stress configurations, hierarchic higher order waveguide models and the automatic coupling of continuum and higher order structural elements using specially designed transition elements that enable an efficient means to study waveguides with local inhomogeneities. In the third stage, the automatic algorithm is used to study wave propagation in hyperelastic waveguides using a few higher order 1D kinematic models. Two variants of a particular hyperelastic constitutive law – the6-constantMurnaghanmodel(for rock like solids) and the 9-constant Murnaghan model(for metallic solids) –are chosen for modeling the material nonlinearity in the analysis. Finally, the algorithm is extended to study energy-momentum conserving time integrators that are derived within a Hamiltonian framework, thus illustrating the extensibility of the algorithm for more complex finite element formulations. In short, the current research deals primarily with the identification and automation of finite element schemes that are most suited for studying wave propagation in hyper-elastic waveguides. Of special mention is the development of a novel unified computational framework that automates the finite element analysis of a large class of problems involving nonlinear plane stress/plane strain, higher order waveguide models and coupling of both continuum and waveguide elements. The thesis, which comprises of 10 chapters, provides a detailed account of various aspects of hyperelastic wave propagation, primarily for 1D waveguides.