Advanced Reactor Physics Methods for Transient Analysis of Boiling Water Reactors

The safety assessment of nuclear power plants requires the consideration of the several physical phenomena taking place in the reactor core. Since the last decade, the simulations are performed using the so-called Best-Estimate (BE) thermal-hydraulic system codes coupled with 3D nodal diffusion reactor dynamics solvers. These numerical tools are well developed and validated for PWR but for BWR there are still improvements and developments to be done. In addition, homogenized cross sections libraries, depending on the individual thermal-hydraulic state parameters, e.g. fuel temperature, moderator density, etc., must be supplied to take into account the interdependencies of the involved physics. In this PhD a new coupled code system named TRADYN was developed that consists of the novel and innovative integration of the core simulator DYN3D into the code system TRACE/PARCS using compiler preprocessor directives. This has the advantage to preserve the original TRACE/PARCS system “untouch” and to facilitate the maintenance, modification and debugging. In order to manage the transfer information between TRACE and DYN3D, a General Interface and Specific Data Map routines in FORTRAN were developed. To properly describe the tightly-coupled neutronics and thermal-hydraulic phenomena within the core of a BWR, different physical models were extended and new ones implemented in DYN3D and PARCS. Another contribution of this doctoral thesis is the development of a new in-house methodology called GENSIM-XS for the generation of nodal cross sections for BWRs considering history effects of control rods and void. GENSIM-XS is able to greatly simplify the number of the neutronics regions present in the reactor core. This new methodology uses the AUDIT option of SIMULATE-3 (S3) to report the cross sections on the output file. Then, they are extracted and written in multi-group tabulated cross sections in NEMTAB format in an automatized manner using Python scripts. The validation of TRADYN is based on Boiling Water Reactor Turbine Trip (TT) benchmark data, where TRADYN has demonstrated its capability to predict the stationary plant conditions as well as the temporal evolution of the main plant parameters, showing a good agreement with the measurements e.g. core power and dome pressure. The static core of the cycle 4 of BWR Laguna Verde nuclear power plant was selected as second case for the validation not only of the GENSIM-XS methodology but also of TRADYN. The TRADYN results such as k-eff, axial power profile, axial void fraction exhibit an excellent agreement with the reference values. This underpins the capabilities of the new methodology to generate cross-sections for coupled thermal-hydraulic/neutronics calculations accounting also for history effects for BWR core analysis

World class manufacturing in micro manufacturers of handmade wooden furniture industry in Puntalarga - Colombia.

This article is divided into ve chapters, namely: rst, the state of the art corresponding to the progress of the department in relation to the objective set in the CONPES 3527 document (2008), which is focused on promoting world class sectors; second, the theoretical review of the subject of World Class Manufacturing, based on the 16 principles proposed by Schonberger (1996) and from other experts in the subject; third, the methodological fra- mework, in which a questionnaire that included the 16 principles mentioned above was designed and administered in order to know the developments of the micro-enterprises of the sector of Puntalarga- Boyacá in the use of tools that make these industries into “world-class” companies; fourth, discussion and analysis of research results; and fth, conclusions. In the methodological phase a survey was used as a technique and a Likert scale questionnaire was used as a tool administered to owners of the 16 companies included in this study. The conclusions show that there are aws in the production and that new strategies to promote the work of these companies are required. This article is divided into ve chapters, namely: rst, the state of the art corresponding to the progress of the department in relation to the objective set in the CONPES 3527 document (2008), which is focused on promoting world class sectors; second, the theoretical review of the subject of World Class Manufacturing, based on the 16 principles proposed by Schonberger (1996) and from other experts in the subject; third, the methodological fra- mework, in which a questionnaire that included the 16 principles mentioned above was designed and administered in order to know the developments of the micro-enterprises of the sector of Puntalarga- Boyacá in the use of tools that make these industries into “world-class” companies; fourth, discussion and analysis of research results; and fth, conclusions. In the methodological phase a survey was used as a technique and a Likert scale questionnaire was used as a tool administered to owners of the 16 companies included in this study. The conclusions show that there are aws in the production and that new strategies to promote the work of these companies are required

Fluctuations in a coupled-oscillator model of the cardiovascular system

We present a model of the cardiovascular system (CVS) based on a system of coupled oscillators. Using this approach we can describe several complex physiological phenomena that can have a range of applications. For instance, heart rate variability (HRV), can have a new deterministic explanation. The intrinsic dynamics of the HRV is controlled by deterministic couplings between the physiological oscillators in our model and without the need to introduce external noise as is commonly done. This new result provides potential applications not only for physiological systems but also for the design of very precise electronic generators where the frequency stability is crucial. Another important phenomenon is that of oscillation death. We show that in our CVS model the mechanism leading to the quenching of the oscillations can be controlled, not only by the coupling parameter, but by a more general scheme. In fact, we propose that a change in the relative current state of the cardiovascular oscillators can lead to a cease of the oscillations without actually changing the strength of the coupling among them. We performed real experiments using electronic oscillators and show them to match the theoretical and numerical predictions. We discuss the relevance of the studied phenomena to real cardiovascular systems regimes, including the explanation of certain pathologies, and the possible applications in medical practice

ALTERNATIVA PARA LA COMERCIALIZACIÓN DEL CHICOZAPOTE (achras sapota): TECNOLOGÃA DE LOS TRATAMIENTOS MÃNIMOS

Chicozapote ( ) is one of the fruit species that at the moment a great potential has, as much commercial as economic, nevertheless, it is a fruit that quickly deteriorates after the harvest taking place diverse biochemical reactions that take to the nondesirable softening, darkening and other aspects, with the consequent loss of the quality of the fruit, thus diminishing its acceptability, and reducing its life utility. A solution to these problems represents the technology of minimum treatments. The objective of this work was to evaluate the effect of diverse conservatives and the temperature on the life utility of fractions of chicozapote. For the accomplishment of this work fruits of chicozapote with a degree of acceptable maturity were used (good color, firmness, size, etc.). 50 fractions of gr. of chicozapote were put under the following treatments: 1) solution of CaCl2 to 1%; 2) a solution of CaCl2 to 2%; 3) ascórbico acid solution and acid citrus, both to 1%; and 4) with solution of ascórbico acid 1,0% and citric acid to 0,5%. All with chlorine (200 ppm). They were dried and they stored to 4, 8 and 22 °C., as variable of answer were evaluated: pH, % acidity, water activity, firmness, ºBrix, reducing sugars, acetaldehído, ethanol, microbiological and sensorial analysis. The best treatment was the 1% mixture ascórbico acid and 0,5% of citric acid with storage to 4°C; prolonging the life of useful of the product until by 36 days, conserving pleasant flavor and color within the accepted characteristics of quality, being the technology of minimum treatments a strategy for the conservation and commercialization of chicozapote.chicozapote, life utility, minimumly process, low temperatures, chicozapote, vida útil, mínimamente procesados, bajas temperaturas, Crop Production/Industries, Marketing,

Efectos de la violencia de pareja en mujeres migrantes

Este estudio analiza la relación entre violencia de pareja, depresión y autoeficacia materna en mujeres migrantes. Se considera que este tipo de violencia produce hundimiento anímico y dificulta el desenvolvimiento como madre. Es un estudio cuantitativo de tipo correlacional explicativo, trabajado con 40 mujeres inmigran- tes con dos a 25 años como residentes, violentadas con al menos un episodio re- ferido y por lo menos un hijo en preescolar. Se utilizaron tres instrumentos, The Parental Involvement and Efficacy, The Survey-Depression Scale y The Re- vised Conflict Tactic Scale. Los resultados arrojaron importantes relaciones entre las variables, mientras más violencia vivan las mujeres, más depresión, y mientras más depresión, menor autoeficacia materna

Kit de entrenamiento sobre la transmisión de señales a través de fibra óptica

El desarrollo de la presenta tesis está orientado a brindar una alternativa técnico – práctica en el campo de las comunicaciones ópticas. El diseño y elaboración de un kit de entrenamiento sobre la transmisión de señales a través de Fibra Óptica permite a través de circuitos básicos poner en práctica los principios que gobiernan el manejo de la luz en el interior de la fibra óptica. Sustentada en un marco teórico, se elaboraron prácticas de laboratorio cuyo objetivo es mostrar variedad de alternativas al momento de realizar una transmisión sobre fibra óptica. Estar en capacidad de reconocer las ventajas de los diferentes tipos de fuentes emisoras de luz y en base a estas poder escoger el receptor más adecuado según el tipo de transmisión deseada sea esta analógica o digital. Se pone énfasis en el empleo de la fibra de plástico mostrando sus principales ventajas frente a la tradicional fibra de vidrio. Tener en consideración las aplicaciones brindadas por la fibra de plástico que en algunas ocasiones sobrepasan los alcances reconocidos con la fibra de vidrio es uno de los objetivos de la presente tesis

Provisos for classic linear oscillator design methods. New linear oscillator design based on the NDF/RRT

In this paper, the classic oscillator design methods are reviewed, and their strengths and weaknesses are shown. Provisos for avoiding the misuse of classic methods are also proposed. If the required provisos are satisfied, the solutions provided by the classic methods (oscillator start-up linear approximation) will be correct. The provisos verification needs to use the NDF (Network Determinant Function). The use of the NDF or the most suitable RRT (Return Relation Transponse), which is directly related to the NDF, as a tool to analyze oscillators leads to a new oscillator design method. The RRT is the "true" loop-gain of oscillators. The use of the new method is demonstrated with examples. Finally, a comparison of NDF/RRT results with the HB (Harmonic Balance) simulation and practical implementation measurements prove the universal use of the new methods