TERMODINÁMICA Y ECONOMÍA Con énfasis en macroeconomía

En este estudio se examinó la teoría propuesta por W. Saslow acerca de la relación entre la Economía y la Termodinámica. Como afirma Saslow, se encontró una analogía entre las variables de estado de ambas ramas. Específicamente se descubrió a partir de una descripción fenomenológica una relación del tipo Gibbs–Duhem en la economía usando las condiciones de Slutsky, y la relación propuesta por la teoría marginalista entre el valor de cambio y el valor de uso.Con el fin de simplificar los cálculos, se supuso que los sistemas económicos se encuentran en equilibrio, con la finalidad de poder hacer la analogía con la Termodinámica de Equilibrio. Además, se aplicó otros supuestos como el de considerar constante la riqueza de un consumidor (microeconomía) o de un país pequeño (macroeconomía) y suponer mensurable (cuantificable) la función económica de utilidad. Del análisis de los datos, se pudo deducir que la teoría de W. Saslow debería ser desarrollada más bien en el campo de la termodinámica de no equilibrio. Al parecer, la economía no es un sistema que permanentemente se encuentre en equilibrio, sino más bien es un sistema dinámico que tiende a cierto equilibrio

Plan de mejora de la logística inversa al reciclaje de residuos de aparatos eléctricos y electrónicos (RAEE) para disminuir los costos en la empresa SKF

La investigación titulada “Plan de mejora de la Logística inversa al reciclaje de residuos de aparatos eléctricos y electrónicos (RAEE) para disminuir los costos en la empresa SKF”, planteando como objetivo Aplicar la norma técnica peruana de gestión de residuos AEE la cual establece lineamientos a ser aplicados para el manejo ambiental adecuado de RAEE con la finalidad de prevenir, reducir y mitigar los impactos negativos que ocasionan sobre la salud y ambiente, el tipo de estudio es aplicada en hechos reales de la compra de los productos eléctricos y/o electrónicos en la empresa. Los métodos usados son cuantitativos para identificar los costos inventarios, el alcance es para el área de compras, servicios de mantenimiento, identificar los equipos actuales en inventario de almacén, los instrumentos de medición es cuestionarios y lista equipos actuales. Al diseñar el plan de mejora de logística inversa de equipos RAEE, se logra establecer una serie de lineamientos, como lo es el conocimiento del Reglamento RAEE, evaluación del negocio, determinación de volumen RAEE, Posibles estrategias de acopio, autodeterminación de meta, identificación del operador RAEE, comunicación y sensibilización, costo y financiamiento de esta manera se diseña el plan de logística inversa con una serie de pasos a seguir para contribuir con la empresa en estudio

Análisis iconográfico de la epigrafía funeraria romana de la provincia de Cáceres

The main objective of this work is to compile and analyse the iconography of the funerary epigraphy in Cáceres during the early Roman Empire, subject so far hardly investigated. Although the images and its study are the main topics in discussion, we also consider necessary the inclusion of the tombstone type, its material and the onomastic content, as crucial collaborators in our task: providing an exhaustive evaluation of the epigraphs. The consideration of the images, not only from an ornamental or religious perspective, but also as an expression of the individual and the community, could allow us to glimpse the creation and evolution of the Hispanic-Roman society in this specific area of the Lusitania.El principal propósito de este escrito es la recopilación y el análisis de las imágenes recogidas en la epigrafía funeraria de Cáceres en época altoimperial, temática hasta el momento poco tratada por la investigación. Si bien la iconografía y su examen son los ejes centrales de nuestro artículo, consideramos también fundamental su conjugación con el estudio del soporte, del material y de la onomástica, puntos capitales para una comprensión completa del epígrafe. La consideración de las imágenes, no ya solo desde una perspectiva ornamental o religiosa, sino como expresión del individuo y de la comunidad, podría permitirnos entrever la creación y la evolución de la sociedad hispanorromana en esta área de la Lusitania

Retroalimentación del proceso de enseñanza basado en evaluación temprana

La deserción estudiantil ha sido un tema de mucha relevancia en las instituciones educativas, por ello se han llevado a cabo diversos estudios en busca de los factores que la generan y las posibles soluciones que la puedan reducir. Uno de los mecanismos que se ha implementado en las universidades para combatir la deserción estudiantil son las evaluaciones docentes, las cuales buscan la opinión que tienen los estudiantes respecto a los docentes que dictaron sus materias durante el semestre. Una vez analizada esta información, se le da a conocer al docente para que así pueda conocer tanto los aspectos negativos como los aspectos positivos identificados por sus alumnos, todo esto con el objetivo de que el docente pueda mejorar su metodología de enseñanza para que el estudiante se sienta más cómodo y así evitar una posible deserción. Con este proyecto se pretende implementar una evaluación docente alternativa, con la cual se realice una retroalimentación docente en las primeras semanas de clase para que los docentes tengan tiempo de corregir acciones identificadas y señaladas por sus alumnos con el objetivo de reducir los indicadores de deserción estudiantil en los diferentes grupos en los cuales se aplique este mecanismo

Las investigaciones sobre estadística y probabilidad en los libros de texto de Bachillerato. ¿Qué se ha hecho y qué se puede hacer?

En este trabajo se recogen y analizan las investigaciones relativas a la presencia de la estadística y la probabilidad en los libros de texto de Bachillerato. Tras caracterizar las distintas tipologías de análisis de libros de texto en matemáticas, se estudian aportaciones, incluyendo revistas, congresos, tesis doctorales y capítulos de libro. Se constata que la investigación ha aumentado notablemente en los últimos cinco años, pero que los trabajos sobre inferencia estadística tienen aún margen de desarrollo respecto a su peso en el currículo de estadística y probabilidad en el Bachillerato. Se realizan, además, varios análisis bibliométricos. Por último, se proporcionan varias ideas y sugerencias respecto a cuáles pueden ser las líneas de futuros trabajos en este campo, incidiendo especialmente en la necesidad de internacionalizar los resultados y de trasladar la investigación a la edición de libros de texto que se ajusten a la evidencia empírica que aportan estas investigaciones

IN VITRO EQUIVALENCE STUDY OF DIFFERENT DOSES OF CARBAMAZEPINE REFERENCE TABLETS USING USP APPARATUSES 2 AND 4

Objective: To perform an in vitro equivalence study of two doses of carbamazepine reference tablets sold in the local market under hydrodynamic conditions of USP Apparatus 4, a dissolution apparatus that better simulates the human gastrointestinal tract. Results were compared with dissolution official conditions using USP Apparatus 2. Methods: Dissolution profiles of both formulations were carried out with an automated USP Apparatus 2 at 75 rpm and 900 ml of dissolution medium. USP Apparatus 4 with laminar flow at 16 ml/min and 22.6 mm cells were used. 1% lauryl sulfate aqueous solution at 37.0±0.5 °C was used as dissolution medium. Spectrophotometric determination of drug at 285 nm was carried out during 60 min. Dissolution profiles were compared with model-independent and-dependent approaches. Results: When comparing dissolution profiles of low vs. high dose similar profiles were found (f2>50) in each dissolution apparatus, however, when the same dose was compared, USP 2 vs. USP 4, opposite results were obtained. Comparison of mean dissolution time and dissolution efficiency data corroborates these results. Weibull function was the best mathematical model that described the in vitro dissolution performance of carbamazepine. No significant differences were found in Td values (low vs. high dose) but opposite results were also found with USP 2 vs. USP 4. Conclusion: Equivalent dissolution performance of two doses of carbamazepine reference tablets were found in each USP dissolution apparatus. The main problem identified in this comparative study is the low dissolution rate and extent found with USP Apparatus 4. More research on this field is necessary for all available doses of reference drug products since the quality of generic formulations depends on the quality of references

Complete Bell Polynomials and Recurrence Relations for Arithmetic Functions

We use the Z-transform to solve a type of recurrence relation satisfied by the number of representations of an integer n as the sum of squares and as the sum of triangular numbers, and also by the color partitions of n; the corresponding solution is in terms of the complete Bell polynomials

Adsorption of Sudan-IV contained in oily wastewater on lipophilic activated carbons: kinetic and isotherm modelling

Up to nine kinetic and fourteen isotherm adsorption models are employed to model the adsorption of Sudan IV, a lipophilic model pollutant present in a biphasic mixture of cyclohexane-water system to simulate oily wastewater. Six different modified activated carbons were used as adsorbents. The highest amount adsorbed of Sudan IV was found in the material prepared by successive treatments of the parent commercial activated carbon Norit ROX 0.8 with nitric acid and urea, followed by thermal treatment at 800 °C under continuous flow of nitrogen. Kinetic and isotherm adsorption models can be employed to simulate the process, since the effect of the presence of water in the adsorption of Sudan IV from the cyclohexane phase was found to be negligible, owing to the high lipophilic character of both adsorbent and adsorbate. All kinetic and isotherm coefficients, coupling with statistical parameters (r2, adjusted r2 and sum of squared errors), are determined by non-linear regression fitting and compared to literature data. The model of Avrami is found to be the most appropriate model to represent the adsorption of the pollutant in any of the six modified carbons tested, the highest value of the kinetic constant being 0.055 min−1. The isotherm adsorption is wellmodelled by using the general isotherm equation of Tóth and the multilayer Jovanović expression for the adsorption of Sudan-IV on that material, resulting in a high monolayer uptake capacity (qm = 193.6 mg g−1).Up to nine kinetic and fourteen isotherm adsorption models are employed to model the adsorption of Sudan IV, a lipophilic model pollutant present in a biphasic mixture of cyclohexane-water system to simulate oily wastewater. Six different modified activated carbons were used as adsorbents. The highest amount adsorbed of Sudan IV was found in the material prepared by successive treatments of the parent commercial activated carbon Norit ROX 0.8 with nitric acid and urea, followed by thermal treatment at 800 °C under continuous flow of nitrogen. Kinetic and isotherm adsorption models can be employed to simulate the process, since the effect of the presence of water in the adsorption of Sudan IV from the cyclohexane phase was found to be negligible, owing to the high lipophilic character of both adsorbent and adsorbate. All kinetic and isotherm coefficients, coupling with statistical parameters (r2, adjusted r2 and sum of squared errors), are determined by non-linear regression fitting and compared to literature data. The model of Avrami is found to be the most appropriate model to represent the adsorption of the pollutant in any of the six modified carbons tested, the highest value of the kinetic constant being 0.055 min−1. The isotherm adsorption is wellmodelled by using the general isotherm equation of Tóth and the multilayer Jovanović expression for the adsorption of Sudan-IV on that material, resulting in a high monolayer uptake capacity (qm = 193.6 mg g−1).This work is a result of Project “AIProcMat@N2020—Advanced Industrial Processes and Materials for a Sustainable Northern Region of Portugal 2020,” with the reference NORTE-01-0145-FEDER-000006, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF); Associate Laboratory LSRE-LCM UID/EQU/50020/2019 funded by national funds through FCT/MCTES (PIDDAC); and CIMO UIDB/00690/2020 through FEDER under Program PT2020.This work i s a re s u l t of Project “AIProcMat@N2020—Advanced Industrial Processes and Materials for a Sustainable Northern Region of Portugal 2020,” with the reference NORTE-01-0145-FEDER-000006, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF); Associate Laboratory LSRE-LCM (UID/ EQU/50020/2019) funded by national funds through FCT/MCTES (PIDDAC); and CIMO (UIDB/00690/2020) through FEDER under Program PT2020.info:eu-repo/semantics/publishedVersio

Removal of Sudan IV from a simulated biphasic oily wastewater by using lipophilic carbon adsorbents

Several chemically and thermally modified activated carbons were tested in the adsorption of a lipophilic pollutant (Sudan IV) contained in biphasic oil-water mixture mimicking petroleum refinery effluents. The effect of different parameters on the adsorption performance has been assessed, such as the absence of water, particle size of the carbon material and the respective chemical and thermal modifications, initial concentration of pollutant, water/oil volume ratio, nature of the organic phase (cyclohexane, n-hexane or n-hexadecane) and the presence of an emulsifier (sodium dodecyl sulphate). Lipophilicity of the adsorbent was found to be a key parameter in the purification of the organic phase. Successive treatments of the parent commercial activated carbon Norit ROX 0.8, namely with nitric acid, urea, followed by a thermal treatment at 800 °C under inert atmosphere, developed the highest adsorption capacity (qe=200 mg·g−1) in the base material. A load of 2.5 g·L−1 of this modified carbon was able to completely remove 500 mg·L−1 of the pollutant from the organic phase after 8 h of contact time, owing to the highest specific surface area (SBET=1055m2·g−1) and characteristic surface chemistry with the lowest content of oxygen surface groups among the tested adsorbents.info:eu-repo/semantics/publishedVersio

Condensation by-products in wet peroxide oxidation: Fouling or catalytic promotion? Part II: Activity, nature and stability

The deposition of condensation by-products onto the catalyst surface upon wet peroxide and wet air oxidation processes has usually been associated with catalyst deactivation. However, in Part I of this paper, it was demonstrated that these carbonaceous deposits actually act as catalytic promoters in the oxygen-assisted wet peroxide oxidation (WPO-O2) of phenol. Herein, the intrinsic activity, nature and stability of these species have been investigated. To achieve this goal, an up-flow fixed bed reactor packed with porous Al2O3 spheres was used to facilitate the deposition of the condensation by-products formed in the liquid phase. It was demonstrated that the condensation by-products catalyzed the decomposition of H2O2 and a higher amount of these species leads to a higher degree of oxidation degree The reaction rates, conversion values and intermediates’ distribution were analyzed. The characterization of the carbonaceous deposits on the Al2O3 spheres showed a significant amount of condensation by-products (~6 wt.%) after 650 h of time on stream. They are of aromatic nature and present oxygen functional groups consisting of quinones, phenols, aldehydes, carboxylics and ketones. The initial phenol concentration and H2O2 dose were found to be crucial variables for the generation and consumption of such species, respectively.This research was supported by the Spanish MINECO through the project CTM-2016-76454-R and by the CM through the project P2018/EMT-4341. M. Munoz thanks the Spanish MINECO for the Ramón y Cajal postdoctoral contract (RYC-2016-20648).info:eu-repo/semantics/publishedVersio