Bentonite fining during different white winemaking stages: effect on the chemical and sensory properties of the wine

This thesis shows the results obtained from adding bentonite at different stages of the alcoholic fermentation in protein stability and reducing the bentonite required to reach stability. Results reflect the effect of this practice on alcoholic fermentation, chemical composition of wines, protein content and profile, aromatic profile and foam quality. The study was carried at pilot and industrial scale, with several grape varieties, in different geographical areas and during three vintages. The advantage of using bentonite during alcoholic fermentation was established, especially in moderate doses, making the addition from the middle of fermentation, obtaining more stable wines with less bentonite. Wines that were stabilized by bentonite treatment during fermentation were the best sensorial evaluated. Reproducibility between scales was confirmed for almost every parameter checked. Protein fractions and bentonite stabilizing dose for the different white wines was also identified and correlated. A commonly used technique was improved, achieving better quality wines.En esta tesis se presentan los resultados de adicionar bentonita en diferentes etapas de la fermentación alcohólica en la estabilidad proteica y en la reducción de la dosis estabilizante de bentonita. Se aprecia el efecto en la fermentación, la composición química de los vinos, el contenido y perfil proteico, el perfil aromático y la calidad de la espuma. El estudio fue realizado a escala piloto e industrial, con diferentes variedades de uva, en distintas zonas geográficas y durante tres vendimias. Se estableció la ventaja de usar bentonita durante la fermentación, especialmente en dosis moderadas a partir de la mitad de la fermentación, obteniéndose vinos más estables con menos bentonita y mejor evaluados sensorialmente. Se confirmó la reproductibilidad entre escalas para la mayoría de los parámetros evaluados. Se identificaron y correlacionaron fracciones proteicas con dosis estabilizante de bentonita. Así se mejoró una técnica comúnmente usada para obtener vinos de mejor calidad

Particle interaction with binary-fluid interfaces in the presence of wetting effects

In this paper, we present an Eulerian-Lagrangian methodology to simulate the interaction between a fluid-fluid interface and a solid particle in the presence of wetting effects. The target physical problem is represented by ternary phase systems in which a solid phase and a drop phase interact inside an incompressible Newtonian carrier fluid. The methodology is based on an Eulerian-Lagrangian approach that allows for the numerical solution of the Continuity and Navier-Stokes equations by using a pseudo-spectral method, whereas the drop phase is modelled by the Phase Field Method, in which a smooth transition layer represented by an hyperbolic function is considered both across the solid-fluid interface and across the drop-fluid interface. Finally, the solid phase is described in the form of a virtual force using the Direct Forcing Immersed Boundary approach. The properties of the immersed solid phase (including wetting effects), the deformability of the drops and the characteristics of the carrier fluid flow are the main controlling parameters. To simulate a ternary phase system, the solid phase is coupled to the binary-fluid phase by introducing a single well potential in the free-energy density functional, which can also control the solid surface wetting property. The capabilities of the methodology are proven by examining first 2D and 3D validation cases in which a solid particle is settling in a quiescent fluid. Then, the interaction of solid particles with a binary-fluid interface and the effects of surface wetting on the submergence of a quasi-buoyant body are discussed. Finally, the equilibrium configuration for a solid particle interacting with an equally-sized drop at different contact angles and the relative rotation of two solid particles bridged by a drop are examined in the case the interaction is induced by shear fluid flow deformations on the drop interface

La Estrategia de Educación a Distancia del Ministerio de Educación Pública durante la Pandemia Covid19 y las Adecuaciones en la Mediación Pedagógica y Funciones Administrativas en el Profesorado de Inglés del Bachillerato San José de Alajuela durante 2020

The pandemic caused by the coronavirus has generated a number of adverse situations in the different scenarios in which human beings develop. Particularly in the educational field, the pandemic caused a massive closure of educational centers that had within their operation to dictate lessons in a face-to-face manner. The socioeconomic environment of the different societies that make up Latin America, especially Costa Rica, have high rates of poverty and extreme poverty, bringing high levels of social dissatisfaction and a high degree of economic and educational inequality for the people who make up the Costa Rican civil society.  In this context, the pandemic has brought a great crisis to the educational pillar because institutions have had to suspend their lessons and migrate to more feasible alternatives such as distance education through technological platforms. This migration has brought a great paradigm shift by incorporating the teaching staff and educational communities to update their way of teaching lessons, with the clear slogan of coping in a better and timely manner the negative impact that the pandemic has had on the activities that human beings perform as the educational part.La pandemia causada por el coronavirus ha generado un sinnúmero de situaciones adversas en los diferentes escenarios en los que se desenvuelven los seres humanos. Particularmente en el ámbito educativo, la pandemia causó un cierre masivo de centros educativos que tenían dentro de su operación el dictar lecciones de manera presencial. El entorno socioeconómico de las diferentes sociedades que conforman Latinoamérica, especialmente la costarricense, tienen grandes índices de pobreza y pobreza extrema trayendo altos grados de insatisfacción social y un alto grado de desigualdad económica y educativa para las personas que conforman la sociedad civil costarricense.  En este contexto la pandemia ha traído una gran crisis al pilar educativo porque las instituciones han tenido que suspender sus lecciones y migrarlas a alternativas más factibles como lo es la educación a distancia a través de plataformas tecnológicas. Esta migración ha traído un gran cambio de paradigma al incorporar al cuerpo docente y a las comunidades educativas a actualizar su manera de dictar lecciones, con la clara consigna de sobrellevar de una mejor y oportuna manera el impacto tan negativo que ha tenido la pandemia en las actividades que los seres humanos realizan como la parte educativa

Effectiveness of psychometric tests for the selection of personnel in jobs in the retail sector

The aim of this study was to determine the effectiveness of psychometric tests in the selection of person- nel in retail sector jobs. The study used the scientific deductive method of explanatory level, with non- experimental design on companies in the retail sector in the region of Junín, Peru. The most relevant psychometric tests in the study was the interview whose intention was to go into the life of the interviewee ensuring, suggestions, opinions and behavioral attitudes, knowledge tests to assess the capabilities and skills of the candidate and finally personality tests that allow to know the working relationship, perfor- mance, satisfaction and staff turnover. The results generated through structural equations, show that the interview, positively influences the selection of personnel (p<0.05). In relation to knowledge tests based on IQ, the results reveal that it had a positive impact on personnel selection (p<0.05). Finally, personality tests based on psychological traits, significantly influence in personnel selection (p<0.05). The conclu- sion of the study indicates that the interview, knowledge tests and personality tests in the selection of personnel contribute to the efficiency of the human resources area, thus optimizing the resources of the organization

Experimental Study on the Detection of Frozen Diffused Ammonia Blockage in the Inactive Section of a Variable Conductance Heat Pipe

Variable Conductance Heat Pipes (VCHP) are mainly employed to cool down electronic systems in spacecraft applications, as they can handle high temperature fluctuations in their cold source, preventing thus the systems from damaging. These fluctuations, as well as ultra-low temperatures, are always present in outer space, and one of the key steps in a VCHP design is therefore to make sure that they endure these conditions. However, not much has been written about their resilience during and after a long exposition to subfreezing conditions, i.e. temperatures lower than the freezing point of the working fluid. In this paper we implement and validate a computational routine based on a modified Flat-Front Approach to predict the VCHP temperature profile and to determine the location of the gas-vapor front. Then we continuously expose an ammonia/stainless-steel VCHP to temperatures below the ammonia freezing point for 211 hours, to later examine the formation and subsequent dynamics of a thin block of frozen ammonia which is diffused into the inactive part of the heat pipe condenser. We describe as well how a strong correlation between the adiabatic section and the reservoir temperatures is maintained (or broken) upon the occurrence (or absence) of the blockage of frozen ammonia.Comment: Under review for possible publication in Applied Thermal Engineerin

Osteotomies for avascular necrosis of the femoral head.

Background: In osteonecrosis of the femoral head (ONFH), blood supply is insufficient for the metabolic requirements of the bone. The initial management is conservative, and, in case of failure, surgery is indicated. Osteotomies aim to change the spatial position of the necrotic portion of the femoral head. This systematic review evaluates the effectiveness and safety of osteotomies for ONFH.Source of data: The systematic review, organized, conducted and reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, was performed on PubMed and Google Scholar. We analysed outcomes in term of Harris Hip Score, leg shortening, secondary collapse and blood loss. We also verified the percentage of patients who required total hip replacement (THR) after osteotomy for ONFH.Areas of agreement: A total of 16 articles were selected, including 775 patients and 852 osteotomies [curved varus osteotomy in 369 (43.3%) patients; transtrochanteric rotational osteotomy in 435 (51.05%) patients; half wedge osteotomy in 48 (5.6%) patients]. There was an overall THR conversion rate of 31.5% (268 hips on 852 osteotomies).Areas of controversy: There were no prospective randomized trials, and the outcome measures employed were often heterogeneous.Growing points: Approximately one-third of the osteotomies performed in cases of ONFH are converted to THR over a period of similar to 7 years. In older patients, primary THR should be considered, especially as the conversion to THR after osteotomy is technically demanding.Areas timely for developing research: Randomized clinical studies should be conducted in order to define the parameters of the patient that can direct towards the most suitable osteotomic technique

Diseño de un sistema de control de temperatura dentro de un prototipo de cuarto de precalentamiento, para lograr un ascenso de temperatura uniforme

El sector avícola en Santander representa el 25% de la producción nacional, es por esto por lo que se deben implementar tecnologías nuevas para mejorar sus procesos. Dentro de estos, existen algunos donde se deben realizar actualizaciones, mejoras o creación de nuevos procesos, uno de ellos es el proceso de precalentamiento, el cual consiste en llevar de manera controlada y homogénea la temperatura interna de los huevos de los 17°C de almacenamiento a un rango entre los 26 a los 28°C, temperatura en la cual inicia el proceso de la embriogénesis. Actualmente se realiza un proceso de atemperado que consiste en climatizar los huevos a temperatura ambiente, esto se hace con el fin de no dar un choque térmico a los huevos al pasar de un cuarto frio a 17°C a los 37.77° C de la incubadora, siendo estos ascensos de temperatura no controlados ni homogéneos. Teniendo en cuenta esta deficiencia, se da la necesidad de crear un cuarto de precalentamiento, donde se garantice un ascenso de temperatura controlada y homogénea. Para el desarrollo de este proyecto se emplea la utilización del controlador Arduino, el cual mediante un control PID se realiza la respectiva medición y control de la temperatura del cuarto a través de Celdas Peltier como actuadores, el control de estas celdas se llevará a cabo mediante la utilización de un Mosfet que permite activaciones mucho más rápidas y seguras que un relé electromecánico, para la medición de la temperatura se emplea el sensor DS18B20.The poultry sector in Santander represents 25% of national production, which is why new technologies must be implemented to improve its processes. Within these, there are some where updates, improvements or the creation of new processes must be carried out, one of them is the preheating process, which consists of bringing the internal temperature of the eggs to 17°C in a controlled and homogeneous manner. storage at a range between 26 to 28°C, temperature at which the process of embryogenesis begins. Currently, a tempering process is carried out that consists of acclimatizing the eggs to room temperature, this is done in order not to give a thermal shock to the eggs when they go from a cold room at 17°C to 37.77°C in the incubator, being these temperature risers neither controlled nor homogeneous. Taking this deficiency into account, there is a need to create a preheating room, where a controlled and homogeneous rise in temperature is guaranteed. For the development of this project, the use of the Arduino controller is used, which by means of a PID control, the respective measurement and control of the temperature of the room is carried out through Peltier cells as actuators, the control of these cells will be carried out by means of the use of a Mosfet that allows much faster and safer activations than an electromechanical relay, for the measurement of the temperature the DS18B20 sensor will be used