Tesis para optar al grado de Magíster en Administración / No disponible a texto completo / El proyecto tiene como objetivo crear una empresa de elaboración y comercialización del carmín, colorante natural que es utilizado en la industria alimenticia, cosmética, textil y farmacéutica, y que se obtiene de la crianza de un insecto denominado Cochinilla del Carmín, cuyo hábitat son las plantas de tuna. El propósito del proyecto es satisfacer una demanda creciente, a nivel mundial, de colorantes de origen natural, debido al cuestionamiento en que han caído los colorantes sintéticos debido a los efectos colaterales cancerígenos que provocan, especialmente los de color rojo. Esto ha llevado que la mayor parte de los países más industrializados, y muchos en vías de desarrollo, hayan establecido normas legales que prohíben el uso de colorantes artificiales en beneficio de los naturales. Si se considera que los colorantes sintéticos representan el 90% del total de colorantes consumidos en el mundo, es esperable un crecimiento fuerte en los próximos años para los colorantes naturales. El proyecto participará en este mercado creciente con un producto de alta calidad y con un rendimiento productivo superior y costos inferiores a la competencia, en virtud a un manejo de cultivo de cochinilla asistido por profesionales, aprovechamiento de exenciones tributarias y aduaneras en una zona franca, beneficios otorgados por el país a las exportaciones, y cercanía con los principales proveedores de materia prima. El proceso productivo del proyecto está conformado por 3 fases: Un ciclo agrícola- biológico para obtener los tunales e infestación asistida de cochinilla, un ciclo industrial para producir el carmín, y un ciclo de comercialización internacional para colocar el producto. La primera producción se obtiene al 21º mes y se logra la producción plena al 30º mes. La estrategia comercial se basa en un contacto directo con el cliente objetivo, que corresponden a los mercados de los países con los cuales Chile ha establecido tratados de libre comercio y acuerdos comerciales. El proyecto requiere un financiamiento de US$ 770.000, los que serán financiados en un 60% por los gestores del proyecto y un 40% por un financista externo, bajo la modalidad de una sociedad anónima cerrada. La evaluación económica determina la viabilidad del proyecto con un Valor Presente Neto de US$ 144.000, una Tasa Interna de Retorno de 19,72% y un Período de Recupero de la Inversión de 2,9 años. 6 Las simulaciones arrojan un alto grado de sensibilidad del proyecto ante cambios en el precio del carmín, del insumo cochinilla, y de los volúmenes de tratamiento de la planta. No obstante, el primer factor presenta una estabilidad histórica, y los otros 2 son controlables por el proyecto. En consideración de los antecedentes expuestos, los gestores del proyectos recomiendan su ejecución.

The purpose of this study is to evaluate the effects and importance of different cross–section representations and energy group structures for steady state and transient analysis. More energy groups may be more accurate, but the calculation becomes much more expensive, hence a balance between accuracy and calculation effort must be find. This study is aimed at comparing a multi–group energy dynamics code, MGT (Multi–group TINTE) with TINTE (TIme Dependent Neutronics and TEmperatures). TINTE’s original version (version 204d) only distinguishes between two energy group structures, namely thermal and fast region with a polynomial reconstruction of cross–sections pre–calculated as a function of different conditions and temperatures. MGT is a TINTE derivative that has been developed, allowing a variable number of broad energy groups. The MGT code will be benchmarked against the OECD PBMR coupled neutronics/thermal hydraulics transient benchmark: the PBMR–400 core design. This comparative study reveals the variations in the results when using two different methods for cross–section generation and multi–group energy structure. Inputs and results received from PBMR (Pty) Ltd. were used to do the comparison. A comparison was done between two–group TINTE and the equivalent two energy groups in MGT as well as between 4, 6 and 8 energy groups in MGT with the different cross–section generation methods, namely inline spectrum– and tabulated cross–section method. The characteristics that are compared are reactor power, moderation– and maximum fuel temperatures and k–effective (only steady state case). This study revealed that a balance between accuracy and calculation effort can be met by using a 4–group energy group structure. A larger part of the available increase in accuracy can be obtained with 4–groups, at the cost of only a small increase in CPU time. The changing of the group structures in the steady state case from 2 to 8 groups has a greater influence on the variation in the results than the cross–section generation method that was used to obtain the results. In the case of a transient calculation, the cross–section generation method has a greater influence on the variation in the results than on the steady state case and has a similar effect to the number of energy groups. / Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2011.

The purpose of this study is to evaluate the effects and importance of different cross–section representations and energy group structures for steady state and transient analysis. More energy groups may be more accurate, but the calculation becomes much more expensive, hence a balance between accuracy and calculation effort must be find. This study is aimed at comparing a multi–group energy dynamics code, MGT (Multi–group TINTE) with TINTE (TIme Dependent Neutronics and TEmperatures). TINTE’s original version (version 204d) only distinguishes between two energy group structures, namely thermal and fast region with a polynomial reconstruction of cross–sections pre–calculated as a function of different conditions and temperatures. MGT is a TINTE derivative that has been developed, allowing a variable number of broad energy groups. The MGT code will be benchmarked against the OECD PBMR coupled neutronics/thermal hydraulics transient benchmark: the PBMR–400 core design. This comparative study reveals the variations in the results when using two different methods for cross–section generation and multi–group energy structure. Inputs and results received from PBMR (Pty) Ltd. were used to do the comparison. A comparison was done between two–group TINTE and the equivalent two energy groups in MGT as well as between 4, 6 and 8 energy groups in MGT with the different cross–section generation methods, namely inline spectrum– and tabulated cross–section method. The characteristics that are compared are reactor power, moderation– and maximum fuel temperatures and k–effective (only steady state case). This study revealed that a balance between accuracy and calculation effort can be met by using a 4–group energy group structure. A larger part of the available increase in accuracy can be obtained with 4–groups, at the cost of only a small increase in CPU time. The changing of the group structures in the steady state case from 2 to 8 groups has a greater influence on the variation in the results than the cross–section generation method that was used to obtain the results. In the case of a transient calculation, the cross–section generation method has a greater influence on the variation in the results than on the steady state case and has a similar effect to the number of energy groups. / Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2011.

Zugl.: Hamburg, Helmut-Schmidt-Universiẗat, Diss.

Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2008.

Traditionally coupled field reactor analysis has been carried out using several loosely coupled solvers, each having been developed independently from the others. In the field of multi-physics, the current generation of object-oriented toolkits provides robust close coupling of multiple fields on a single framework. This research investigates the suitability of such frameworks, in particular the Open-source Field Operation and Manipulation (OpenFOAM) framework, for the solution of spatial reactor dynamics problems. For this a subset of the theory of the Time-dependent Neutronics and Temperatures (TINTE) code, a time-dependent two-group diffusion solver, was implemented in the OpenFOAM framework. This newly created code, called diffusionFOAM, was tested for a number of steady-state and transient cases. The solver was found to perform satisfactorily, despite a number of numerical issues. The object-oriented structure of the framework allowed for rapid and efficient development of the solver. Further investigations suggest that more advanced transport methods and higher order spatial discretization schemes can potentially be implemented using such a framework as well. / Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2008.

Traditionally coupled field reactor analysis has been carried out using several loosely coupled solvers, each having been developed independently from the others. In the field of multi-physics, the current generation of object-oriented toolkits provides robust close coupling of multiple fields on a single framework. This research investigates the suitability of such frameworks, in particular the Open-source Field Operation and Manipulation (OpenFOAM) framework, for the solution of spatial reactor dynamics problems. For this a subset of the theory of the Time-dependent Neutronics and Temperatures (TINTE) code, a time-dependent two-group diffusion solver, was implemented in the OpenFOAM framework. This newly created code, called diffusionFOAM, was tested for a number of steady-state and transient cases. The solver was found to perform satisfactorily, despite a number of numerical issues. The object-oriented structure of the framework allowed for rapid and efficient development of the solver. Further investigations suggest that more advanced transport methods and higher order spatial discretization schemes can potentially be implemented using such a framework as well. / Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2008.

Die vorliegende Arbeit beschreibt die Synthese und Charakterisierung ethylenglykolfunktionalisierter Carboxylate der Münzmetalle sowie deren Verwendung als Präkursoren in der Herstellung von Nanopartikeln und leitfähigen Metallschichten. Ein Schwerpunkt der Arbeit liegt auf der Verwendung von Kupfer(II)-carboxylaten zur Herstellung von druckbaren Kupfertinten. Es wird gezeigt, wie zentrale Präkursoreigenschaften durch Variation der Carboxylatreste optimiert werden können. Einen zweiten Schwerpunkt bildet die Herstellung von Kupfernanopartikeln durch thermische Zersetzung ethylenglykolfunktionalisierter Kupfercarboxylate. Der Einsatz von Bis- und Tris(triphenylphosphan)kupfer(I)-carboxylaten ermöglicht hierbei die Herstellung von oxidfreien sphärischen Kupfernanopartikeln sowie von Kupferstäbchen unter einfachen experimentellen Bedingungen. Weitere Arbeiten widmen sich der Verwendung von ethylenglykolfunktionalisierten Silber(I)-carboxylaten zur Synthese von Silbernanopartikeln. Der entwickelte Prozess erlaubt die Herstellung blättchenförmiger Silbernanopartikel bei vergleichsweise niedrigen Temperaturen. Auch die Herstellung von blättchenförmigen Kupfersulfidpartikeln durch Thermolyse eines ethylenglykolfunktionalisierten Bis(triphenylphosphan)kupfer(I)-thiocarboxylates wird beschrieben. Schließlich wird gezeigt, wie thermolytisch hergestellte Goldnanopartikel an ethylenglykolfunktionalisierten Kohlenstoffnanoröhren abgeschieden werden können. Der Prozess wurde auf einem Wafer durchgeführt. Die erhaltenen Strukturen ermöglichen eine Verwendung als optischer Sensor.

Self-assembled microsphere monolayers (SMMs) hold significant promise for micro- and nanopatterning. Here we exploit, for the first time, SMMs as stamps for microcontact printing (μCP) and demonstrate this to fabricate patterned initiator templates that can subsequently be amplified into polymer brushes by surface initiated atom transfer radical polymerization (SI-ATRP). SMM stamps avoid the need for expensive and sophisticated instrumentation in pattern generation, and provide a broad range of accessible surface chemistries and pitch size control.

Self-assembled microsphere monolayers (SMMs) hold significant promise for micro- and nanopatterning. Here we exploit, for the first time, SMMs as stamps for microcontact printing (μCP) and demonstrate this to fabricate patterned initiator templates that can subsequently be amplified into polymer brushes by surface initiated atom transfer radical polymerization (SI-ATRP). SMM stamps avoid the need for expensive and sophisticated instrumentation in pattern generation, and provide a broad range of accessible surface chemistries and pitch size control.