Optimization Of Temperature Field Evolution Simulation During Wet Flat Grinding

We have considered the analytical solutions for heat transfer in wet flat grinding, assuming a linear and a constant heat flux profile, entering into the workpiece. We assume as well a constant heat transfer coefficient for the coolant acting on the workpiece surface. In order to avoid thermal damage, we provide a very fast method for the computation of the maximum temperature, which occurs on the workpiece surface in the stationary regime. We also provide a very rapid method for the numerical evaluation of the transient regime duration (relaxation time). By knowing the location of the maximum temperature and the relaxation time, we have performed an analysis for the computation optimization of the temperature evolution on the workpiece surface. This kind of analysis offers a very interesting simulation tool to avoid thermal damage during the transient regime.Ciencias Experimentale

Characterization of Different Functionalized Lipidic Nanocapsules as Potential Drug Carriers

Lipid nanocapsules (LNC) based on a core-shell structure consisting of an oil-filled core with a surrounding polymer layer are known to be promising vehicles for the delivery of hydrophobic drugs in the new therapeutic strategies in anti-cancer treatments. The present work has been designed as basic research about different LNC systems. We have synthesized—and physico-chemically characterized—three different LNC systems in which the core was constituted by olive oil and the shell by different phospholipids (phosphatidyl-serine or lecithin) and other biocompatible molecules such as Pluronic® F68 or chitosan. It is notable that the olive-oil-phosphatidyl-serine LCN is a novel formulation presented in this work and was designed to generate an enriched carboxylic surface. This carboxylic layer is meant to link specific antibodies, which could facilitate the specific nanocapsule uptake by cancer cells. This is why nanoparticles with phosphatidyl-serine in their shell have also been used in this work to form immuno-nanocapsules containing a polyclonal IgG against a model antigen (C-reactive protein) covalently bounded by means of a simple and reproducible carbodiimide method. An immunological study was made to verify that these IgG-LNC complexes showed the expected specific immune response. Finally, a preliminary in vitro study was performed by culturing a breast-carcinoma cell line (MCF-7) with Nile-Red-loaded LNC. We found that these cancer cells take up the fluorescent Nile- Red molecule in a process dependent on the surface properties of the nanocarriers

Native and fermented waxy cassava starch as a novel gluten-free and clean label ingredient for baking and expanded product development

Amylose-free and wild-type cassava starches were fermented for up to 30 days and oven- or sun-dried. The specific volume (ν) after baking was measured in native and fermented starches. The average ν (across treatments) for waxy starch was 3.5 times higher than that in wild-type starches (17.6 vs. 4.8 cm3 g−1). The best wild-type starch (obtained after fermentation and sun-drying) had considerably poorer breadmaking potential than native waxy cassava (8.4 vs. 16.4 cm3 g−1, respectively). The best results were generally obtained through the synergistic combination of fermentation (for about 10–14 days) and sundrying. Fermentation reduced viscosities and the weight average molar mass led to denser macromolecules and increased branching degree, which are linked to a high loaf volume. The absence of amylose, however, was shown to be a main determinant as well. Native waxy starch (neutral in taste, gluten-free, and considerably less expensive than the current alternatives to cassava) could become a new ingredient for the formulation of clean label-baked or fried expanded products

Esofagitis eosinofílica en el adulto: aspectos clínicos, endoscópicos, pH-métricos y manométricos Eosinophilic esophagitis in the adult: clinical, endoscopic, pH-metric, and manometric findings

Objetivos: la esofagitis eosinofílica (EE) es una entidad de interés creciente caracterizada en el adulto por disfagia y episodios de impactación alimentaria recurrentes. Nuestro objetivo fue estudiar las características clínicas, endoscópicas, manométricas y pH-métricas en los pacientes con EE, así como la relación que pudiera existir entre ellas. Pacientes y métodos: se estudiaron de forma prospectiva durante un año los pacientes adultos diagnosticados de EE. En todos se realizó endoscopia digestiva alta con toma de biopsias, manometría esofágica estacionaria y pH-metría ambulatoria. Se documentó además el tiempo de evolución clínica, los antecedentes de atopia, la presencia de eosinofilia periférica, la frecuencia de la disfagia y el número de desimpactaciones y complicaciones endoscópicas. Resultados: se estudiaron 11 pacientes (edad media 35 años). Todas las endoscopias presentaron hallazgos patológicos: traquealización en 5, alteraciones mucosas en 4, en 3 anillos esofágicos distales y en 2 estenosis esofágicas. Precisaron desimpactaciones endoscópicas 7 pacientes. Se produjeron desgarros de la mucosa esofágica durante la endoscopia en 2 pacientes. La manometría esofágica fue patológica en 6 pacientes, de estos, 5 fueron trastornos de hipomotilidad. La pH-metría fue patológica en 2 casos. Presentaron eosinofilia periférica 3 pacientes. Conclusión: aunque los hallazgos patológicos en la endoscopia son frecuentes, no siempre justifican los episodios de impactación alimentaria característicos de la EE. Los trastornos de motilidad en forma de peristalsis esofágica ineficaz son el hallazgo manométrico más frecuente, aunque tampoco se han podido relacionar con un mayor número de episodios de disfagia o de impactaciones.Objectives: eosinophilic esophagitis (EE) is a condition characterized by dysphagia and frequent food impaction in young adults. The aim of our study was to evaluate the clinical aspects, endoscopic features, pH-metric and motility disorders in EE. Patients and methods: adult patients with EE were prospectivity included. Endoscopy with biopsy, stationary esophageal manometry, and 24-hour pH-metry were performed. We analyzed the duration of disease, allergies, blood peripheral eosinophilia, prevalence of dysphagia, number of food impaction episodes, and complications during the endoscopic procedure. Results: eleven male patients with a mean age of 35 years were followed. Endoscopy showed esophageal disorders in all cases: 5 esophageal felinizations, mucosal abnormalities in 4 cases, distal rings in 3 cases, and 2 esophageal stenoses. In two cases mucosal tearing during the endoscopic procedure was described. In 6 patients the manometric study showed motor disorders affecting the esophageal body, 5 of them displaying hypomotility. Two patients showed pathological gastroesophageal reflux during pH-monitoring. Blood peripheral eosinophilia was detected in 3 patients. Conclusion: although endoscopic abnormalities are frequently found, they do not usually explain dysphagia and food impaction episodes in EE. Ineffective esophageal peristalsis is the most prevalent manometric disorder associated with this entity, although it is not clearly related to symptom worsening either

A comparison of energy use, water use and carbon footprint of cassava starch production in Thailand, Vietnam and Colombia

Energy use, water use and greenhouse gas (GHG) emissions were assessed for the transformation of cassava roots into starch by two small-scale (ST1, ST2: 1-2 t starch per day) and one large-scale (VLT: 100-200 t starch per day) technologies. The goal of the study was to identify hotspots of energy use and GHG emissions, as well as sustainable practices, with a view to uncover opportunities to improve the environmental performance of cassava starch production. VLT required 2527 MJ/t starch, mainly (77%) from biogas used to dry starch, but was the most efficient in terms of water use (10 m3/t starch) due to the practice of water recycling between unit operations. ST1 and ST2 were similar in terms of electricity use (212 MJ/t starch), and were able to rely on solar energy to dry starch, due to the small volumes of production. In contrast, water use varied from 21 to 62 m3/t starch due to differences in the design of the rasping and starch recovery (extraction) operations. GHG emissions were 149, 93 and 105 kg CO2eq/t starch for VLT, ST1 and ST2 respectively. For ST1 and ST2, methane emissions from untreated wastewater were the main contribution to GHG emissions. For VLT, methane was captured to produce biogas and to dry starch, and the main contribution to GHG emissions was the use of non-renewable grid electricity. Biogas technology was adopted in the past 12 years in the case of VLT. Previously fuel oil was used instead of biogas, which resulted in GHG emissions of 539 kg CO2eq/t starch. VLT used markedly more electricity than ST1 and ST2, which was necessary to ensure the high output and consistent starch quality. Strategies to reduce the impacts of cassava starch production could focus on (1) increasing the energy efficiency of the drying operation, in order to make more biogas available for other uses such as production of renewable electricity; (2) improving the design of some unit operations with regards to water and energy efficiency; and (3) promoting the transfer and adoption of water recycling practices. (Résumé d'auteur

Efecto de los tratamientos termo-mecánicos en la respuesta tribológica de una aleación Fe-Mn-Al-C para aplicaciones industriales.

El desgaste severo en elementos de máquinas y sistemas mecánicos es una problemática persistente a nivel nacional y mundial la cual requiere ser atendida de forma integral y frontal mediante soluciones innovadoras. El desarrollo de nuevos materiales que satisfagan requerimientos de mínimo costo, gran durabilidad y un satisfactorio desempeño mecánico-tribológico para diferentes condiciones de uso en la industria, es la motivación que ha impulsado grandes revoluciones en la ingeniería lo cual es esencial para una solución integral al problema vigente, Así, surge la idea de desarrollar y reemplazar parcial o totalmente gran cantidad de materiales convenciones por nuevas aleaciones resistentes al desgaste. Las aleaciones del sistema Fe-Mn-Al-C prometen ser uno de los materiales sustitutos, principalmente por sus propiedades mecánicas que en algunos casos son superiores a las del los aceros inoxidables y aceros Hadfield