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En las últimas décadas, la industria de las bebidas alcohólicas se ha intensificado debido a la demanda del mercado peruano, para ello es necesario el uso de técnicas industriales que nos sirvan para optimizar la obtención de bebidas cada vez más puras. Para esto se hace evidente el manejo correcto de variables que influyen en una destilación, tales como el tipo de bebida fermentada, presión de vacío, grado alcohólico y absorbancia. En el presente trabajo, se utilizó la chicha de jora, la cual es una bebida fermentada, principalmente de maíz, a la muestra de chicha se colocó en el equipo de destilación, siendo evaluadas las siguientes variables: presión, tipo de chicha y grado alcohólico. Asimismo se utilizó el líquido destilado de la chicha de jora, en la que se evaluó el efecto de la presión (385-760 mmHg) y el tipo de chicha (blanca y oscura), sobre la absorbancia y el grado alcohólico de las muestras. Para el procesamiento de los datos obtenidos se ingresaron los valores en Microsof Excel, luego para obtener un modelo experimental en el programa DATAFIT, el mismo que nos dio una ecuación exponencial de la siguiente forma: y = exp(a*x1+b*x2+c*x3+d), en la misma que la variable dependiente es la absorbancia. Por lo cual se ha encontrado que si existe una relación entre presión, grado alcohólico, tipo de chicha obteniendo una tendencia negativa en el modelo.

En el presente trabajo se evaluó la influencia de la temperatura (25°C a 55°C) , la presión de vacío (0.2 bar a 0.8 bar) y la concentración de enzima biopectinasa (0g/300mL a 0.2g/300mL) , en la resistencia de la torta (m/kg) y la resistencia del medio filtrante(m-1), utilizando un diseño compuesto central rotacional (DCCR), resultando en que la concentración de biopectinasa y la temperatura tienen efecto sobre la resistencias de la torta y del Medio Filtrante, además se halló que a partir de una temperatura de 50°C ésta no tuvo influencia sobre la Resistencia de la torta, además la mayor influencia de la temperatura en la resistencia de la torta se obtuvo entre 40°C y 45°C. También se obtuvo que las variables independientes estudiadas no afectan significativamente a la resistencia del medio filtrante.

Abstract Although coveted in applications, few materials expand when subject to compression or contract under decompression, i.e., exhibit negative compressibility. A key step to achieve such counterintuitive behaviour is the destabilisations of (meta)stable equilibria of the constituents. Here, we propose a simple strategy to obtain negative compressibility exploiting capillary forces both to precompress the elastic material and to release such precompression by a threshold phenomenon – the reversible formation of a bubble in a hydrophobic flexible cavity. We demonstrate that the solid part of such metastable elastocapillary systems displays negative compressibility across different scales: hydrophobic microporous materials, proteins, and millimetre-sized laminae. This concept is applicable to fields such as porous materials, biomolecules, sensors and may be easily extended to create unexpected material susceptibilities.

BackgroundRobotic mitral repair is generally performed with four intercostal trocars and a minithoracotomy. We describe our technique and results with a totally-thoracoscopic closed chest approach using a 12 mm valveless trocar as “working port”, without a minithoracotomy. We compared our results with this technique with a control group of robotic mitral repairs performed earlier with a minithoracotomy.MethodsReview of all patients with degenerative mitral valve disease who underwent robotic mitral valve repair surgery since December 2019 (n = 110). Patients with concomitant procedures (n = 8) were excluded. The remaining 102 patients were divided in two groups, depending on the approach used, minithoracotomy (n = 63) and totally thoracoscopic (n = 39).ResultsThere were no significant differences between groups regarding preoperative characteristics. All procedures were completed robotically as planned, and repair rate was 100%. The minithoracotomy group showed a higher percentage of leaflet resections (17.9% vs. 38.7%; p = 0.03). All surgical times were significatively reduced in the totally thoracoscopic group: Cardiopulmonary bypass (97 vs. 115 min, p = 0.0008), ischemic time (67 vs. 80 min, p = 0.0013) and total surgical time (185 vs. 225 min; p

Pool boiling of liquid water has many practical applications in daily life and industry, including steam accumulators. Thus, pool boiling on polymeric surface coatings with nanoporous microparticle addition for boiling heat transfer coefficient (HTC) enhancement and potential for solid-solid phase change material (PCM) encapsulation have been studied. The study focuses on the effect of surface wettability on the boiling HTC and the vapor barrier properties of the different polymeric surfaces, measured by means of corrosion analysis on the substrate surface.Pure polyvinylidene fluoride (PVDF) yields high HTC at low wall superheat (ΔTwall) values, both with hydrophilic and binary nanoparticle addition. Moreover, combination of polyimide (P84) with hydrophilic and binary mixture of nanoporous microparticles shows great thermal performance in the same ΔTwall regime. In addition, PVDF and P84 seem to be promising candidates for solid-solid PCM encapsulation, as they showed good mechanical resistance and vapor permeation properties, with and without containing hydrophilic silica nanoporous microparticles. Hydrophobic silica nanoporous microparticle addition led to an immediate vapor blanket generation that significantly hindered heat transfer and augmented substrate surface corrosion.

Abstract Rain erosion on the leading edge of wind turbine blades is an intricate engineering challenge for the wind industry. Based on an energetic approach, this work proposes a methodology to characterise the erosion capacity of the raindrop impacts onto the leading edge blades. This methodology can be used with meteorological data from public institutions or from direct measurements at the wind turbine locations. The erosion characterisation is analysed using accumulative and per impact erosive variables, that is, total kinetic energy and kinetic energy per impact. To consider the frequency of impacts, two erosive variables are proposed, namely, total kinetic power and kinetic power per impact. These variables are calculated using the data from the Royal Netherlands Meteorological Institute (Koninklijk Nederlands Meteorologisch Instituut, KNMI) of the last 25 years jointly with the operation specifications of an actual wind turbine model (Suzlon S111). The main contribution to the erosive variables was found to be the wind speed because it controls the rotational velocity of the wind turbine. Also, the intensity of the rainfall and the frequency of meteorological data logging, that is, the temporal resolution of data, play a significant role.

Drinking water treatment plants (DWTP) use chlorination as an oxidation stage in the first step of the processes used to eliminate the natural organic matter (NOM) responsible for the formation of 2-methylisoborneol (2-MIB) and Geosmin (GM), which produce odor and taste to the water. However, chlorination processes give rise to disinfectant toxic subproducts, such as trihalomethanes (THMs). In this work, a headspace solid-phase microextraction coupled with a gas chromatography/mass spectrometric method has been developed for the quality control of drinking water. 2-MIB, GM, and THMs at different stages of the drinking water treatment process were monitored. The method was validated following the Environmental Protection Agency guidelines. Neither carryover nor the matrix effect was observed. The performance of the method was satisfactory in terms of selectivity, repeatability, and accuracy and exhibited a linear concentration range of 0.8–50 µg/L for trichloromethane (TCM), 0.05–20 µg/L for bromodichloromethane, 0.01–20 µg/L for dibromochloromethane and tribromomethane, and 0.005–0.05 µg/L for GM and 2-MIB. The THMs concentration obtained for all the water samples was below the thresholds established by international organizations and, for 2-MIB and GM, were lower for their limit of quantification. The method was also applied to the adsorption kinetic study of TCM on granulated activated carbon, which is the main barrier to reducing the NOM in DWTP.

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El color de los cálices de la jamaica (Hibiscus sabdariffa L.) es un criterio de calidad considerado por el consumidor y se relaciona con la concentración de ciertos fitoquímicos. No se tiene información sobre la relación de este parámetro con las características fisicoquímicas de los extractos acuosos en variedades de Hibiscus cultivadas en México, por lo que el objetivo del presente trabajo fue determinar el color de cálices de ocho variedades de jamaica y establecer su relación con algunas variables químicas de los extractos acuosos obtenidos. Para ello se midió el color de los cálices (enteros y molidos) y el de los extractos con ayuda de un colorímetro Hunter-Lab. En los extractos se determinó el contenido de antocianinas totales (ANT), ácido ascórbico (AA), acidez titulable (AT), pH y °Brix. Se encontró que el color de los cálices y de los extractos influyó en el contenido de antocianinas y ácido ascórbico. Las variedades de cálices oscuros presentaron entre cinco y siete veces más antocianinas que las de cálices claros, mientras que la variedad de cálices blancos tuvo el mayor contenido de ácido ascórbico. De los parámetros de color, la luminosidad de los cálices molidos puede usarse como estimador del contenido de antocianinas totales, por la elevada correlación negativa entre estas variables.