Дисертації з теми "Reduced formulation"

The objective of this study was to investigate how to decrease the viscosity of reduced fat chocolate. This was with the aim of improving the industrial feasibility and the sensory properties of reduced fat chocolate.

High-flying unmanned reconnaissance and surveillance systems are now being used extensively in the United States military. Current development programs are producing demonstrations of next-generation unmanned flight systems that are designed to perform combat missions. Their use in first-strike combat operations will dictate operations in densely cluttered environments that include unknown obstacles and threats, and will require the use of terrain for masking. The demand for autonomy of operations in such environments dictates the need for advanced trajectory optimization capabilities. In addition, the ability to coordinate the movements of more than one aircraft in the same area is an emerging challenge. This thesis examines using an analytical reduced order formulation for trajectory generation for minimum time and terrain masking cases. First, pseudo-3D constant velocity equations of motion are used for path planning for a single vehicle. In addition, the inclusion of winds, moving targets and moving threats is considered. Then, this formulation is increased to using 3D equations of motion, both with a constant velocity and with a simplified varying velocity model. Next, the constant velocity equations of motion are expanded to include the simultaneous path planning of an unspecified number of vehicles, for both aircraft avoidance situations and formation flight cases.

Background: Natural progesterone is currently unavailable for the treatment of endometrial hyperplasia. The first line of treatment for this condition is with the synthetic progestins Medroxyprogesterone Acetate (MPA) and Levonorgestrel (LNG). However, these hormones frequently trigger side effects which occur as a result of adverse gene and protein regulation. The current unavailability of natural progesterone is down to its poor bioavailability which is due to the low aqueous solubility and extensive first-pass metabolism of this compound. Aims: The first aim of this thesis is to compare natural progesterone with MPA and LNG in their regulation of a subset of genes and proteins in the endometrium whilst also assessing the selected proteins in biopsies from patients with endometrial hyperplasia before and after progestin therapy. The second aim is to study progesterone metabolism within the gastrointestinal tract and liver in order to direct the production of progesterone amorphous solid dispersions. Methodology: During this thesis both microbiological and pharmacological laboratory techniques were used. For microbiology investigations immunohistochemistry, polymerase chain reaction, InCell Analysis and enzyme-linked immunosorbent assay were the key research methods. For pharmacological research the main methods used were stability assays analysed by tandem mass spectrometry and high performance liquid chromatography, solvent emulsion evaporation, powder x-ray diffraction and scanning electron microscopy. Conclusions: Amorphous solid dispersions are an attractive option for the future production of a natural progesterone oral formulation with enhanced solubility. Such a formulation can be targeted for delivery to the distal small intestine where progesterone metabolism is reduced compared to other intestinal regions. This formulation would be of particular benefit to patients with endometrial hyperplasia as the most commonly used progestins to treat this disease were shown to differentially regulate genes and proteins in the human endometrium compared to the natural product.

La réduction d'ordre de modèles d'un problème de contact demeure un sujet de recherche important en mécanique numérique des solides.Nous proposons une extension de l'hyper-réduction avec domaine d'intégration réduit à la mécanique du contact sans frottement s'écrivant à l'aide d'une formulation mixte.Comme la zone de contact potentiel se limite au domaine réduit, nous faisons le choix de prendre comme base réduite pour la variable duale (représentative des forces de contact) la base du modèle d'ordre plein restreinte.Nous obtenons ainsi un modèle hyper-réduit hybride avec une approximation de la variable primale par des modes empiriques et de la variable duale par les fonctions de base des éléments finis. Si nécessaire, la condition inf-sup de ce modèle peut être forcée par une approximation hybride la variable primale. Cela mène à une stratégie hybride combinant un modèle d'ordre hyper-réduit et un modèle d'ordre plein permettant l'obtention d'une meilleure approximation de la solution sur la zone de contact.Un post-traitement permettant la reconstruction des multiplicateurs de Lagrange sur l'ensemble de la zone de contact est également introduit.De manière à optimiser la sélection des snapshots, un indicateur d'erreur simple et efficace est avancé pour être couplé à un algorithme glouton
The model order reduction of mechanical problems involving contact remains an important issue in computational solid mechanics.An extension of the hyper-reduction method based on a reduced integration domain to frictionless contact problems written by a mixed formulation is proposed.As the potential contact zone is naturally reduced through the reduced domain, the dual reduced basis is chosen as the restriction of the dual full-order model basis.A hybrid hyper-reduced model combining empirical modes for primal variables with finite element approximation for dual variables is then obtained.If necessary, the inf-sup condition of this hybrid saddle point problem can be enforced by extending the hybrid approximation to the primal variables. This leads to a hybrid hyper-reduced/full-order model strategy. By this way, a better approximation on the potential contact zone is furthermore obtained.A post-treatment dedicated to the reconstruction of the contact forces on the whole domain is introduced.In order to optimize the snapshots selection, an efficient error indicator is coupled to a greedy sampling algorithm leading to a robust reduced-order model

The first objective of this Dissertation is to present a methodology to calculate analytically the mode shapes and corresponding natural frequencies and determine critical buckling loads of mechanically coupled microbeam resonators with a focus on micromechanical filters. The second objective is to adopt a nonlinear approach to build a reduced-order model and obtain closed-form expressions for the response of the filter to a primary resonance. The third objective is to investigate the feasibility of employing subharmonic excitation to build bandpass filters consisting of either two sets of two beams coupled mechanically or two sets of clamped-clamped beams. Throughout this Dissertation, we treat filters as distributed-parameter systems. In the first part of the Dissertation, we demonstrate the methodology by considering a mechanical filter composed of two beams coupled by a weak beam. We solve a boundary-value problem (BVP) composed of five equations and twenty boundary conditions for the natural frequencies and mode shapes. We reduce the problem to a set of three linear homogeneous algebraic equations for three constants and the frequencies in order to obtain a deeper insight into the relation between the design parameters and the performance metrics. In an approach similar to the vibration problem, we solve the buckling problem to study the effect of the residual stress on the static stability of the structure. To achieve the second objective, we develop a reduced-order model for the filter by writing the Lagrangian and applying the Galerkin procedure using its analytically calculated linear global mode shapes as basis functions. The resulting model accounts for the geometric and electric nonlinearities and the coupling between them. Using the method of multiple scales, we obtain closed-form expressions for the deflection and the electric current in the case of one-to-one internal and primary resonances. The closed-form solution shows that there are three possible operating ranges, depending on the DC voltage. For low DC voltages, the effective nonlinearity is positive and the filter behavior is hardening, whereas for large DC voltages, the effective nonlinearity is negative and the filter behavior is softening. We found that, when mismatched DC voltages are applied to the primary resonators, the first mode is localized in the softer resonator and the second mode is localized in the stiffer resonator. We note that the excitation amplitude can be increased without worrying about the appearance of multivaluedness when operating the filter in the near-linear range. The upper bound in this case is the occurrence of the dynamic pull-in instability. In the softening and hardening operating ranges, the adverse effects of the multi-valued response, such as hysteresis and jumps, limit the range of the input signal. To achieve the third objective, we propose a filtration technique based on subharmonic resonance excitation to attain bandpass filters with ideal stopband rejection and sharp rolloff. The filtration mechanism depends on tuning two oscillators such that one operates in the softening range and the other operates in the hardening range. Hardware and logic schemes are necessary to realize the proposed filter. We derive a reduced-order model using a methodology similar to that used in the primary excitation case, but with all necessary changes to account for the subharmonic resonance of order one-half. We observe that some manipulations are essential for a structure of two beams coupled by a weak spring to be suitable for filtration. To avoid these complications, we use a pair of single clamped-clamped beams to achieve our goal. Using a model derived by attacking directly the distributed-parameters problem, we suggest design guidelines to select beams that are potential candidates for building a bandpass filter. We demonstrate the proposed mechanism using an example.
Ph. D.

Dynamic and steady state modeling and simulation validation of an industrial depropanizer owned by Petrobras are carried out in the Equation-Oriented environment using EMSO (Environment for Modeling, Simulation and Optimization). The depropanizer is a high purity distillation column with high nonlinear behavior because of the strong interactions due to the vapor recompression. Furthermore, the difference between internal and external material/energy flows causes a complex multitime-scale dynamics. Modeling such process is a challenging problem due to these characteristics. Initially, a steady state model, robust, fast and precise, able to provide steady state predictions that are necessary for effective implementation of Real Time Optimization (RTO) was developed in EMSO. In addition, the modeling of dynamic equilibrium processes often results in higher index DAE systems. Usually, phenomenological relationships are used to solve the index problem, but this approach gives rise to errors as a result of unknown parameters and project details that are assumed. Considering that the column\'s response to composition changes, in general, takes place over a timescale one or two order of magnitude slower than those of flow rate changes, an approach similar to a proportional loop with arbitrarily large gain is used as an alternative to solve the index problem. The dynamic model structure is based on the steady state model and contains more than nine thousand equations. Validation simulation results from comparison between real plant data and dynamic model have shown that the proposed approach is able to predict the dynamic behavior of the column properly.
O propósito desta dissertação é realizar a modelagem, simulação e validação de um modelo, tanto em estado estacionário quanto dinâmico, de uma unidade despropanizadora da Petrobras. Para o estudo foi utilizado o ambiente orientado a equações, EMSO (Environment for Modeling, Simulation and Optimization). A coluna despropanizadora é uma torre de destilação de alta pureza que possui um comportamento altamente não-linear devido às fortes interações causadas pelo sistema de recompressão do vapor. A modelagem desse processo é um desafio devido às características que apresenta. Inicialmente, foi desenvolvido nesse ambiente um modelo em estado estacionário, robusto, rápido e preciso, com a finalidade de prover as predições em estado estacionário necessárias para a implementação efetiva de uma rotina de otimização em tempo real, Real Time Optimization (RTO). A modelagem dinâmica de processos em equilíbrio resulta, frequentemente, em sistemas de equações algébrico diferenciais de índice superior. Para solução do problema de índice normalmente são utilizadas relações fenomenológicas, as quais introduzem novas fontes de erros provenientes de parâmetros e detalhes de projeto desconhecidos. Considerando que a resposta da coluna em relação às mudanças na composição, em geral, ocorre em uma escala de tempo de ordem de grandeza duas vezes mais lenta que as respostas às mudanças nas vazões, foi proposta uma abordagem similar a um controlador proporcional com ganho elevado para substituir as relações fenomenológicas e assim resolver o problema de índice. A estrutura do modelo dinâmico é baseada na do modelo estacionário e contém mais de nove mil equações. A validação dos resultados da simulação com dados reais da planta mostra que a abordagem proposta consegue prever satisfatoriamente o comportamento do sistema.

A milk and egg mixture was processed at 96C and 92C with 10 sec hold times and evaluated for nutritional composition, functional characteristics, and shelf-life. The process was more than sufficient to destroy Coxiella burnetti and Salmonella senftenberg which were the most heat resistant organisms of concern in processing this milk and egg mix. The spoilage organisms received 2,200 D and 425 D processes, respectively, which were more than adequate for providing a safe product and extending the shelf life of the product for seven weeks under refrigerated storage conditions. Both sweetened and unsweetened formulations were evaluated. The nutritional profile of the milk and egg mix was improved when dried eggs (solids and liquid proportion equivalent to whole egg) were replaced with dried egg white, cholesterol reduced egg yolk, and skim milk. The fat and cholesterol were reduced between 22 to 33% and 37 to 44%, respectively, in the cholesterol reduced formulation (CRF) as compared to the control formulation (CF). The protein content of the milk and egg mix was not altered by utilization of cholesterol - reduced egg yolk in the CRF as compared to the CF. Addition of beta-galactosidase decreased the lactose up to 96%. The CF were more yellow than the CRF in the mixes and baked gels (p< 0.05). There were also no difference in gel strength between the baked gels made from the two formulations. There were no significant chemical and physical changes over the seven week storage period of the product at refrigerated conditions (p< 0.05).
Master of Science

L'objectif de ce travail consiste à développer la méthode de résolution PGD (Proper Generalized Decomposition), qui est une méthode de réduction de modèle où la solution est recherchée sous forme séparée, à la résolution des équations de Navier-Stokes. Dans un premier temps, cette méthode est appliquée à la résolution d'équations modèles disposant d'une solution analytique. L' équation de diffusion stationnaire 2D et 3D, l'équation de diffusion instationnaire 2D et les équations de Burgers et Stokes sont traitées. Nous montrons que dans tous ces cas la méthode PGD permet de retrouver les solutions analytiques avec une précision équivalente au modèle standard. Nous mettons également en évidence la supériorité de la PGD par rapport au modèle standard en terme de temps de calcul. En effet, dans tous ces cas, laPGD se montre beaucoup plus rapide que le solveur standard (plusieurs dizaine de fois). La résolution des équations de Navier-Stokes isothermes et anisothermes est ensuite effectuée par une discrétisation volumes finis sur un maillage décalé où le couplage vitesse-pression a été géré à l'aide d'un schéma de prédiction-correction. Dans ce cas une décomposition PGD sur les variables d'espaces uniquement a été choisie. Pour les écoulements incompressibles 2D stationnaire ou instationnaire, de type cavité entrainée et/ou différentiellement chauffé, les résultats obtenus par résolution PGD sont similaires à ceux du solveur standard avec un gain de temps significatif (la PGD est une dizaine de fois plus rapide que le solveur standard). Enfin ce travail introduit une première approche de la résolution des équations de transferts par méthode PGD en formulation spectrale. Sur les différents problèmes traités, à savoir l'équation de diffusion stationnaire, l'équation de Darcy et les équations de Navier-Sokes, la PGD a montré une précision aussi bonne que le solveur standard. Un gain de temps a été observé pour le cas de l'équation de Poisson, par contre, concernant le problème de Darcy ou les équations de Navier-Stokes les performances de la PGD en terme de temps de calcul peuvent encore être améliorées.

Dans cette thèse, tout d’abord, nous faisons l’Analyse Mathématique du modèle exact du chauffage radiatif d’un corps semi-transparent $\Omega$ par une source radiative noire qui l’entoure. Il s’agit donc d’étudier le couplage d’un système d’Equations de Transfert Radiatif avec condition au bord de réflectivité indépendantes avec une équation de conduction de la chaleur non linéaire avec condition limite non linéaire de type Robin. Nous prouvons l’existence et l’unicité de la solution et nous démontrons des bornes uniformes sur la solution et les intensités radiatives dans chaque bande de longueurs d’ondes pour laquelle le corps est semi-transparent, en fonction de bornes sur les données, Deuxièmement, nous considérons le problème du contrôle optimal de la température absolue à l’intérieur du corps semi-transparent $\Omega$ en agissant sur la température absolue de la source radiative noire qui l’entoure. À cet égard, nous introduisons la fonctionnelle coût appropriée et l’ensemble des contrôles admissibles $T_{S}$, pour lesquels nous prouvons l’existence de contrôles optimaux. En introduisant l’espace des états et l’équation d’état, une condition nécessaire de premier ordre pour qu’un contrôle $T_{S}$ : t ! $T_{S}$ (t) soit optimal, est alors dérivée sous la forme d’une inéquation variationnelle en utilisant le théorème des fonctions implicites et le problème adjoint. Ensuite, nous considérons le problème de l’existence et de l’unicité d’une solution faible des équations de la thermoviscoélasticité dans une formulation mixte de type Hellinger- Reissner, la nouveauté par rapport au travail de M.E. Rognes et R. Winther (M3AS, 2010) étant ici l’apparition de la viscosité dans certains coefficients de l’équation constitutive, viscosité qui dépend dans ce contexte de la température absolue T(x, t) et donc en particulier du temps t. Enfin, nous considérons dans ce cadre le problème du contrôle optimal de la déformation du corps semi-transparent $\Omega$, en agissant sur la température absolue de la source radiative noire qui l’entoure. Nous prouvons l’existence d’un contrôle optimal et nous calculons la dérivée Fréchet de la fonctionnelle coût réduite
This thesis begins with a rigorous mathematical analysis of the radiative heating of a semi-transparent body made of glass, by a black radiative source surrounding it. This requires the study of the coupling between quasi-steady radiative transfer boundary value problems with nonhomogeneous reflectivity boundary conditions (one for each wavelength band in the semi-transparent electromagnetic spectrum of the glass) and a nonlinear heat conduction evolution equation with a nonlinear Robin boundary condition which takes into account those wavelengths for which the glass behaves like an opaque body. We prove existence and uniqueness of the solution, and give also uniform bounds on the solution i.e. on the absolute temperature distribution inside the body and on the radiative intensities. Now, we consider the temperature $T_{S}$ of the black radiative source S surrounding the semi-transparent body $\Omega$ as the control variable. We adjust the absolute temperature distribution (x, t) 7! T(x, t) inside the semi-transparent body near a desired temperature distribution Td(·, ·) during the time interval of radiative heating ]0, tf [ by acting on $T_{S}$. In this respect, we introduce the appropriate cost functional and the set of admissible controls $T_{S}$, for which we prove the existence of optimal controls. Introducing the State Space and the State Equation, a first order necessary condition for a control $T_{S}$ : t 7! $T_{S}$ (t) to be optimal is then derived in the form of a Variational Inequality by using the Implicit Function Theorem and the adjoint problem. We come now to the goal problem which is the deformation of the semi-transparent body $\Omega$ by heating it with a black radiative source surrounding it. We introduce a weak mixed formulation of this thermoviscoelasticity problem and study the existence and uniqueness of its solution, the novelty here with respect to the work of M.E. Rognes et R. Winther (M3AS, 2010) being the apparition of the viscosity in some of the coefficients of the constitutive equation, viscosity which depends on the absolute temperature T(x, t) and thus in particular on the time t. Finally, we state in this setting the related optimal control problem of the deformation of the semi-transparent body $\Omega$, by acting on the absolute temperature of the black radiative source surrounding it. We prove the existence of an optimal control and we compute the Fréchet derivative of the associated reduced cost functional

M. Tech. Polymer Technology.
The gas permeability of composite epoxy resins formulated with graphene platelets and glass flakes was investigated. The purpose of researching the gas permeability of the composite resins was to develop a possible coating system that could prevent or limit the release of radioactive gases like tritium from irradiated graphite waste which may accumulate in underground repositories. Helium was used as a substitute gas to simulate the diffusive properties of tritium gas.

Two studies were carried out to determine if nitrogen excretion could be reduced through ration formulation, while maintaining milk production in dairy cows. In each study, 18 lactating Holstein cows were randomly assigned to treatment sequences in a 3 x 3 Latin Square design, replicated 6 times. Milk, blood, and rumen fluid samples were taken during the third week of each 28 day experimental period in the first experiment, and during the second and third week of each 28 day period in the second experiment. Total collection of urine and feces occurred during the last 5 days of each experimental period. In the first experiment, total mixed rations were formulated to contain 15.3 (A), 16.4 (B), and 12.3% (C) crude protein. Ration A (control) contained a standard 18% dairy concentrate, ration B was balanced in terms of protein and carbohydrate degradation and rates of passage using the Cornell Net Carbohydrate and Protein System (CNCPS), and ration C was a low protein diet balanced to meet the amino acid requirements of the cows using the CNCPS model. There was a reduction (P<0.05) in dry matter intake among cows fed diets A, B, and C (22.8, 21.8, and 20.8 kg d⁻¹, respectively). Milk production and milk protein output were lower (P<0.05) for the cows fed the low protein diet than for the other two diets, but N efficiency expressed as milk nitrogen as a % of intake nitrogen tended to be greater (P>0.05) for animals on the low protein diet. Blood urea nitrogen values were different (P<0.05) among treatment groups (14.0, 19.1 and 6.8 mg dl⁻¹ for diets A, B, and C, respectively), but blood non-esterified fatty acid levels were unaffected by dietary treatment. Fecal nitrogen excretion was lower (P<0.05) for cows fed diet C than for those fed diet A, but was not different from those fed diet B. Daily urinary nitrogen varied significantly (P<0.05) among the 3 dietary groups (0.154, 0.180 and 0.092 kg d"1, for diets A, B, and C, respectively). Nitrogen balance was not different (P<0.05) among treatments. In the second experiment, total mixed rations were balanced in terms of degradation, rates of passage, and amino acid requirements using the CNCPS model. Rumen-protected lysine and methionine were used to balance amino acid requirements in diets B and C. Crude protein levels in the diets were 18.3, 16.7 and 15.3% CP, for diets A, B, and C, respectively. Diet A resulted in higher (P<0.05) dry matter intakes than diets B and C. Milk production was lower (P<0.05) for cows fed diets B and C than for cows fed diet A (34.2, 32.8 and 32.8 kg/d for diets A, B, and C, respectively) but, milk protein output did not differ (P>0.05) among dietary groups. Nitrogen efficiency, expressed as milk N as a % of intake nitrogen, improved (P<0.05) for diet B compared to diet A, and for cows on diet C compared to cows on diets B or A (25.8, 29.3, and 33.1%, respectively). Blood urea nitrogen values were different (P<0.05) among groups (15.9, 12.9, and 10.0 mg/dl for diets A, B, and C, respectively). Treatment differences (P<0.05) were seen in plasma arginine, aspartate, isoleucine, methionine, threonine and valine concentrations. Plasma methionine levels were (P<0.05) higher for cows fed diets B and C compared to those fed diet A, but no differences (P>0.05) were seen in plasma lysine concentrations. Although there was a significant decrease (P<0.05) in apparent crude protein digestibility among cows fed diets A, B, and C, respectively, urinary nitrogen excretion was decreased (P<0.05) dramatically (0.264, 0.195, and 0.162 kg d⁻¹, for diets A, B, and C, respectively). Fecal nitrogen excretion and nitrogen balance were not affected (P>0.05) by diet.

The utilization of in vitro tests with a tiered testing strategy for detection of mild ocular irritants can reduce the use of animals for testing, provide mechanistic data on toxic effects, and reduce the uncertainty associated with dose selection for clinical trials. The first section of this thesis describes how in vitro methods can be used to improve the prediction of the toxicity of chemicals and ophthalmic products. The proper utilization of in vitro methods can accurately predict toxic threshold levels and reduce animal use in product development. Sections two, three and four describe the development of new sensitive in vitro methods for predicting ocular toxicity. Maintaining the barrier function of the cornea is critical for the prevention of the penetration of infections microorganisms and irritating chemicals into the eye. Chapter 2 describes the development of a method for assessing the effects of chemicals on tight junctions using a human corneal epithelial and canine kidney epithelial cell line. In Chapter 3 a method that uses a primary organ culture for assessing single instillation and multiple instillation toxic effects is described. The ScanTox system was shown to be an ideal system to monitor the toxic effects over time as multiple readings can be taken of treated bovine lenses using the nondestructive method of assessing for the lens optical quality. Confirmations of toxic effects were made with the utilization of the viability dye alamarBlue. Chapter 4 describes the development of sensitive in vitro assays for detecting ocular toxicity by measuring the effects of chemicals on the mitochondrial integrity of bovine cornea, bovine lens epithelium and corneal epithelial cells, using fluorescent dyes. The goal of this research was to develop an in vitro test battery that can be used to accurately predict the ocular toxicity of new chemicals and ophthalmic formulations. By comparing the toxicity seen in vivo animals and humans with the toxicity response in these new in vitro methods, it was demonstrated that these in vitro methods can be utilized in a tiered testing strategy in the development of new chemicals and ophthalmic formulations.