Composisicón química y cinética de producción de gas in vitro del salvado de maíz

LA DIGESTIBILIDAD IN VITRO DE LOS GRANOS La industria de la elaboración de harina de maíz, almidones, féculas y levaduras contribuye al 13.1% del valor bruto de la cadena productiva de este grano en México (Financiera Rural, 2011). El salvado de maíz corresponde a la fracción fibrosa, no leñosa que se obtiene luego de la extracción de los almidones contenidos en la semilla para la industria de la producción de harinas para consumo humano (Figura 1). El pericarpio es la parte estructural más externa del grano y se divide en tres capas; epicarpio (0.7 a 1 mm) mesocarpio (4 a 6 mm) y endocarpio, el espesor del pericarpio normalmente varía de 60 a 80 mm, está formado por un tejido denso y correoso, cuya composición es 69.7 % fibra, 19.1 % proteína, 7.3 % almidón, 1 % grasa y 4.4 % de otras sustancias (Bartolo-Pérez et al., 1999). La fibra está formada fundamentalmente por: Hemicelulosa (67 %), celulosa (23 %) y lignina (0,%) (Burga y Duensing, 1989)

Rheological study of the aggregation state of alumina nanofluids

Se adjunta una comunicación, aunque se han publicado tres comunicaciones más.The presence of alumina solid particles in aqueous phase induces a change in the viscosity of the suspension from Newtonian to non- Newtonian flow. Besides, the presence of solid particles is adequate for the use as a heat exchanger fluid. The effect of nanoparticle size on thermal properties of nanofluids is still today a question, which is far from being answered. In this respect, the results reported in the literature are contradictory [1], probably due to the formation of aggregates when particles are dispersed in the liquid phase. Regarding to the nanoparticle shape influence in thermal conductivity, cylinders and spheres have been considered as the more effective in heat transfer. Spherical nanoparticles of alumina, which is one of the most investigated nanofluid, dispersed in water were used in this study. TEM images showed a mean average diameter of 50 nm. However, DLS measurements showed monodispersed particles of 260 nm. Very recently [2], the relationship between shear rheology and aggregation state of suspensions has been reviewed. Mechanical and physical properties of the resultant materials depend on shape, size and size distribution, which are considered determining parameters in the formation of particle aggregates. The steady shear flow (figure 1) has shown that these clusters, when they are at rest, are formed by highly branched aggregates that erode when shear rate increases, until a suspension of individual particles is achieved. These results are in good agreement with the intrinsic viscosity obtained by Money and Krieger-Dougherty models. In both cases, these values are far from the 2.5 corresponding to spherical particles. The temperature effects were also taken into account.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Effect of labour flexibility on productivity in the andalusian hotel industry

In this work, we analyze the effect of labour flexibility on productivity in the Andalusian hotel industry. For this purpose, we use the data obtained by the Quality, Productivity and Competitiveness in the Hospitality Industry for Andalusia project (PO7/SEJ-02889). Using a expanded version of the Cobb-Douglas production function, the model distinguishes two employment shares: full-time permanent (standard work) and temporary plus part-time employees (non-standard work). Our results indicate that productivity in Andalusian hotels is lower the higher the percentage of temporary and part-time workers. Furthermore, there are no statistically significant differences between the negative impact on productivity of both types of labour contract. However, since the costs associated with both temporary and part-time workers are lower than those of workers with full-time permanent contracts, future studies should analyze the differential impact of all the types of contracts discussed on the mean cost per employee in hotels.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Aplicación del sistema de costeo por órdenes para determinar la rentabilidad por orden en la empresa Alta Sierra SAC-Trujillo 2019

El presente trabajo de investigación busca determinar la rentabilidad por orden de la empresa Alta Sierra SAC mediante la aplicación del sistema de costeo por órdenes de producción en las dimensiones costo de material directo, costo de mano de obra directa y costos indirectos de fabricación, así mismo la rentabilidad se midió mediante el índice de rentabilidad de margen bruto. En el estudio es no-experimental de tipo descriptivo aplicativo donde se examinaron 7 órdenes de producción efectuadas en el mes de abril 2019, se aplicó como técnica el análisis documental, observación y la entrevista utilizando como instrumentos las fichas de análisis documental, las hojas de observación y el cuestionario respectivamente, con el propósito de recolectar datos, así mismo analizar información, que permitió cumplir el desarrollo de los objetivos trazados. Se obtuvo cómo resultado al determinar la rentabilidad de cada orden producida una rentabilidad favorable o positiva en 5 órdenes de producción y habiendo pérdida económica o habiendo rentabilidad negativa en 2 órdenes. Debido a que la empresa no contaba con un instrumento de gestión como es un sistema de costos, dando como consecuencia a que la gerencia tomara malas decisiones como en la fijación de precios de algunos de sus productos, puesto que anteriormente solo se calculaba la rentabilidad de manera global más no en cada producto u orden solicitada; con la aplicación del sistema del costeo por órdenes la empresa cuenta con información real de cuanto fue el costo en cada una de las órdenes lo que le permitirá a la gerencia controlar y administrar los costos de producción, así mismo de contribuir a mejorar la toma decisiones

The Solar Internetwork. II. Magnetic Flux Appearance and Disappearance Rates

Small-scale internetwork magnetic fields are important ingredients of the quiet Sun. In this paper we analyze how they appear and disappear on the solar surface. Using high resolution Hinode magnetograms, we follow the evolution of individual magnetic elements in the interior of two supergranular cells at the disk center. From up to 38 hr of continuous measurements, we show that magnetic flux appears in internetwork regions at a rate of $120\pm3$ Mx cm$^{-2}$ day$^{-1}$ ($3.7 \pm 0.4 \times 10^{24}$ Mx day$^{-1}$ over the entire solar surface). Flux disappears from the internetwork at a rate of $125 \pm 6$ Mx cm$^{-2}$ day$^{-1}$ ($3.9\pm 0.5 \times 10^{24}$ Mx day$^{-1}$) through fading of magnetic elements, cancellation between opposite-polarity features, and interactions with network patches, which converts internetwork elements into network features. Most of the flux is lost through fading and interactions with the network, at nearly the same rate of about 50 Mx cm$^{-2}$ day$^{-1}$. Our results demonstrate that the sources and sinks of internetwork magnetic flux are well balanced. Using the instantaneous flux appearance and disappearance rates, we successfully reproduce the time evolution of the total unsigned flux in the two supergranular cells.Comment: 8 pages, 6 figures. Accepted in ApJ. An animation of the right panel of Figure 1 is available at http://spg.iaa.es/pub/downloads/gosic/figure1_right_panel.ta