Diseño y Simulación de un Deshidratador Mixto Indirecto de Frutas/Design and simulation of an Indirect Mixed Fruit Dehydrator

En el presente estudio se determinaron las características del diseño para un Deshidratador Mixto Indirecto (DMI) con una capacidad de 50 kg. Este deshidratador está constituido por el colector solar, placa de absorción, cubierta, ducto de succión, ventilador, resistencias eléctricas, zona de secado y ducto de aireación. Los elementos fueron diseñados mediante el programa SolidWorks, que permitió la simulación mecánica y termodinámica del proceso de secado, mediante el cual se pudieron determinar las características de los elementos del equipo. Se calculó que la temperatura óptima para la deshidratación de las frutas está entre los 40 y 70 ∘C. El calor específico del compartimiento de secado fue uniforme, con un valor de 2860,8 J/(kg.K); con la ayuda del ventilador se logró homogenizar el flujo del aire a la temperatura de deshidratación: a 50∘C fue homogénea en la zona de secado. Los resultados obtenidos en la simulación vaticinan un correcto funcionamiento del equipo. The present study determined the design characteristics for an Indirect Mixed Dehydrator (IMD) with a capacity of 50 kg. The solar collector, absorption plate, cover, suction duct, fan, electric resistances, drying zone and aeration duct constitute this dehydrator. The elements were designed trough the SolidWorks program, which allowed the mechanical and thermodynamic simulation of the drying process; by which it was possible to determine the elements' characteristics of the equipment. The optimum temperature for the dehydration of fruits was between 40 and 70 ∘C. The specific heat of the drying compartment was uniform and has a value of 2860.8 J / (kg K), with the help of the fan it is possible to homogenize the air flow at the dehydration temperature: at 50 ∘C it was homogeneous in the drying zone. The results obtained in the simulation guarantee the correct functioning of the equipment. Palabras Clave: Deshidratador Mixto Indirecto, Deshidratador de Frutas, simulación mecánica y termodinámica. Keywords: Indirect Mixed Dehydrator, Fruit Dehydrator, mechanical and thermodynamics simulatio

Utilización de GEOGEBRA como herramienta metodológica en la enseñanza de la geometría Analítica y su incidencia en el control del rendimiento académico de estudiantes del primer semestre de ingeniería

The present investigation aims to demonstrate that the use of GEOGEBRA for the teaching of Analytical Geometry affects the improvement of the academic performance of students in engineering careers. For the work carried out, a descriptive-correlational analysis was used analyzing two homogeneous groups of students legally registered in the Chair of Linear Algebra and Analytical Geometry, in the first one the traditional method was applied with classroom activities and for the second a semiotic system was used by means of the utilization of GEOGEBRA which is a mathematical software characterized by its versatility and didactic in the teaching of analytical Geometry as well as its applications in vector calculation, differential and integral calculus with one and more variables. To validate the hypothesis, we used the Student t-statistic, recommended for samples of up to 50 elements, with which the comparison between the two means is made with an error level of 5% which indicates the area of risk of rejection of the null hypothesis and acceptance of the research hypothesis with 95% confidence. After performing the statistical analysis, p-value = 0.00099191 was obtained, so when it is less than 0.05, the null hypothesis is rejected, accepting the research hypothesis, verifying that the application of GEOGEBRA has a positive impact on the improvement of the academic performance of students by 21.27%.A presente investigação visa demonstrar que o uso de GEOGEBRA para o ensino de Geometria Analítica afeta a melhoria do desempenho acadêmico de estudantes em carreiras de engenharia. Para trabalhar uma análise descritiva-correlacional analisar dois grupos homogéneos de alunos legalmente registradas no Departamento de Álgebra Linear e Geometria Analítica no primeiro método tradicional foi aplicada a atividades de sala de aula eo segundo um sistema semiótico foi usado foi usado por através da utilização de geogebra que é um programa matemático caracterizada pela sua versatilidade e didáctica no ensino de geometria analítica para além das suas aplicações no cálculo de vetor, diferencial e cálculo integral com um e mais variáveis. Foram utilizados o teste t de Student estatístico recomendado para amostras, com 50 elementos, com os quais é realizada a comparação entre dois meios com um nível de erro de 5%, o que indica a área de risco de rejeição para validar a hipótese a hipótese nula e aceitação da hipótese de pesquisa com 95% de confiança. p-valor após análise estatística, foi obtido = 0.00099191 de modo a ser inferior a 0,05 a hipótese nula é rejeitada, aceitando a hipótese de pesquisa, a verificação de que a aplicação de geogebra afecta positivamente melhoria desempenho acadêmico dos alunos em 21,27%.La presente investigación tiene como objetivo demostrar que la utilización de GEOGEBRA para la enseñanza del Geometría Analítica incide en el mejoramiento del rendimiento académico de estudiantes en carreras de ingeniería. Para el trabajo realizado se utilizó un análisis descriptivo-correlacional analizando dos grupos homogéneos de estudiantes legalmente matriculados en la catedra de Algebra Lineal y Geometría Analítica, en el primero se aplicó el método tradicional con actividades áulicas y para el segundo se utilizó un sistema semiótico por medio de la utilización de GEOGEBRA el cual es un software matemático caracterizado por su versatilidad y didáctica en la enseñanza de Geometría analítica además de sus aplicaciones en el cálculo vectorial, cálculo diferencial e integral con una y más variables. Para validar la hipótesis se utilizó el estadístico t-Student, recomendado para muestras de hasta 50 elementos, con el cual se realiza el comparativo entre las dos medias con un nivel de error del 5%, el cual indica el área de riesgo de rechazo de la hipótesis nula y aceptación de la hipótesis de investigación con un 95% de confianza. Luego de realizar el análisis estadístico, se obtuvo p-value=0,00099191 por lo que al ser menor de 0,05 se rechaza la hipótesis nula, aceptando la hipótesis de investigación, comprobando que la aplicación del GEOGEBRA incide positivamente en el mejoramiento del rendimiento académico de los estudiantes en un 21.27%

Wild harvest : Distribution and diversity of wild food plants in rice ecosystems of Northeast Thailand

Rice fields provide not only a staple food but are also bio-diverse and multi-functional ecosystems. Wild food plants are important elements of biodiversity in rice fields and are critical components to the subsistence of poor farmers. The spatial and seasonal distribution of wild food plants were analysed across different sub-systems occurring within paddy ecosystems in two adjacent rice farming villages in Kalasin, Northeast Thailand. Data were collected in 102 sampling sites corresponding to seven sub-systems including tree rows, mounds, field margins, shelters, ponds, pond margins and levees. Frequency of occurrence and absolute abundance were quantified for each species in the two seasons of two years, and data on uses of wild food plant species were collected through focus group discussions. A total of 42 species from 28 botanical families were reported, and one third of these have been classified as weeds of rice by other authors. Results show that species abundance, frequency of occurrence and diversity varied seasonally and spatially within paddy rice ecosystems. Higher diversity indexes were observed in the monsoon in most sub-systems. The most diverse sub-systems in the monsoon were shelters, mounds and pond margins, and tree rows and mounds in the dry season. Field margins, ponds and levees presented lower diversity, but are habitat of aquatic species important for the local diet, such as Ipomoea aquatica and Marsilea crenata. The herbs Lobelia sp. and Glinus oppositifolius, classified as rice weeds, were most abundant species in the dry season and frequently consumed. Leucaena leucocephala, of which the roots, leaves and fruits are commonly consumed as vegetable, was the most abundant tree in most sub-systems. More than half of the species were specific to one or two sub-systems due to particular niche requirements. Three quarters of wild food plant species had additional uses besides food; with ten different types of use and multiple use categories occurring in the different sub-systems. This study highlights that the development of more productive lowland rice systems may jeopardize the diversity of wild food plant species in the rice landscape, which is important for the food security of the rural poor.</p

Spatial and seasonal diversity of wild food plants in home gardens of Northeast Thailand

Wild food plants (WFPs) are major components of tropical home gardens, constituting an important resource for poor farmers. The spatial and seasonal diversity of WFPs was analyzed across multi-species spatial configurations occurring within home gardens in a rice farming village in northeast Thailand. Data were collected in 77 sampling sites corresponding to five different home garden spatial configurations, namely fenced plot, fenced plot margin, yard, home garden boundary, and pot. Absolute abundance and frequency of occurrence were quantified per individual WFP species in both dry and rainy seasons, and data on additional uses (besides food) were collected through focus group discussions for each WFP species. A total of 20 species corresponding to 13 botanical families were reported. Results show that species abundance and frequency of occurrence varied seasonally and spatially within home gardens. Diversity, as observed in the analysis of Shannon and Simpson diversity indexes, also differed seasonally and across different spatial configurations. Home gardens showed higher diversity in the dry season because of the presence of human management. Ninety-five percent of the WFP species presented additional uses, with nine different types of uses in total. Finally, as this study demonstrates, the results on both the spatial and seasonal diversity of WFPs over different spatial configurations comprise a new perspective in home garden research by providing new understandings about their composition and management