Optimum cork stopper diameter for a proper wine sealing performance when modifying bottleneck diameter: a first approach

Aim of study: This study present a theoretical model that allow establishing the proper relationship between forces and diameters that take part in sealing for ensuring an adequate closure during storage time, and obtained the optimum stopper diameter for a proper sealing performance when modifying bottleneck diameter.Area of study: The proposed model is of interested to the whole cork value chain from forest owners to natural cork stoppers manufacturers.Material and methods: The optimum cork stopper diameter depends mainly on stopper quality and the compression rate applied in the bottling operation. In this study, we establish the stopper diameter when reducing bottleneck diameter, applying a compression rate of 33% when corking, and for natural cork stoppers which quality allows to recover its initial diameter to 96% after 24 h since compression.Main results: For a bottleneck diameter of 18 mm, the value of the stopper diameter should be at least of 22.3 mm, and for a bottleneck diameter of 17 mm, the value of the stopper diameter should be at least of 20.3 mm.Research highlights: These results try to solve one of the main worries of natural cork stopper manufacturers, which is the scarcity of raw cork suitable for manufacturing them. However this study is also of interested to forest owners because the increment of cork suitable for natural cork stoppers manufacturing means an increment in cork value.Key words: bottling; corking; compression force; compression rate; diameter recovery; relaxation force; relaxation ratio.Abbreviations used: Ds (Cork Stopper Diameter); Dg (Caliper Diameter the Corking Machine); Db (Bottleneck Diameter); Dr (Recovered Diameter); Fc (Compression Force); Fr (Relaxation Force);  CR (Compression Rate); RR (Relaxation Ratio); RD (Diameter Recovery)

El pensamiento de Florentino González

El documento presenta una carta dirigida al señor Don J. M. Torres Caicedo, escrita desde Valparaíso, el 1 de septiembre de 186

Presupuesto nacional para el servicio del año económico de 1848 a 1849

Presupuesto nacional para el servicio del año económico de 1848 a 1849 proyectado por Florentino Gonzále

Erosive wear resistance regarding different destabilization heat treatments of austenite in high chromium white cast iron, alloyed with mo

With the aim of improving erosive wear resistance in hypoeutectic white cast irons with 18% Cr and 2% Mo, several samples of this grade were subjected to different heat treatments at 1000 °C to destabilize the austenite. The dwell times at this temperature varied from 4 to 24 h and the samples were cooled in air or oil. The existing phases were identified and quantified by applying the Rietveld structural refinement method. The results were correlated with the hardness of the material and with the microhardness of the matrix constituent. The greatest resistance to erosive wear was achieved in those samples that had a higher percentage of secondary carbides. The longer the dwell time at the destabilization temperature of austenite, the greater the amount of precipitated secondary carbides. However, the percentage of dissolved eutectic carbides is also higher. These eutectic carbides were formed as a result of non-equilibrium solidification. Low cooling rates (in still air) can offset this solution of eutectic carbides via the additional precipitation of secondary carbides in the 600−400 °C temperature range. A sharp decrease is observed in the percentage of retained austenite in those treatments with dwell times at 1000 °C equal to or greater than 12 h, reaching minimum values of around 2% volume. The percentage of retained austenite was always lower after oil quenching and the hardness of oil quenched samples was observed to be greater than those quenched in air. In these samples, the maximum hardness value obtained was 993 HV after a 12 h dwell, which result from the optimum balance between the percentages of retained austenite and of precipitated carbides

Certificación de competencias en el marco de la formación continua a lo largo de la vida: contexto y metodología

Se presenta un panorama general sobre el concepto y la práctica de certificación y acreditación de aprendizajes no formales e informales y el contexto en el que nace. Se enumeran una serie de puntos para destacar la aportación que el principio de acreditación de aprendizajes adquiridos en la experiencia puede aportar a la formación y los puntos de debate más relevantes en el momento actual. Finalmente se destacan los diferentes modelos de acreditación existentes en cada contexto social.A general panorama of the concept and practice of the certification and accreditation of non-formal and formal learning is presented along with their context. A series of points are listed to highlight how the principle of accreditation of learning acquired through experience contributes to education and the most important issues being debated at the current time are also presented. Finally, the different models of accreditation for each social context are given

Adenoma sebáceo de la glándula parótida

Los tumores de las glándulas salivales constituyen un área importante de la patología oral y maxilofacial. La mayor parte de las neoplasias glandulares salivales son benignas, representando las malignas entre el 15 y el 32% del total. La localización más común de estas entidades es la glándula parótida, en la que asientan hasta el 80% de todos los casos. En este artículo se presenta un caso de adenoma sebáceo salival, de localización parotídea. El tumor, formado por células epiteliales que tapizan conductos, exhibe amplias áreas de diferenciación sebácea y zonas con metaplasia oncocítica. El patrón histológico es predominantemente quístico, observándose cavidades rellenas con material sebáceo. Si bien la presencia de glándulas sebáceas en las glándulas salivales es frecuente, las neoplasias exclusivamente formadas por las mismas son muy infrecuentes. Dada su rareza, este tumor plantea problemas diagnósticos diferenciales con otras entidades benignas y malignas. Su tratamiento implica la extirpación de la lesión, lo que generalmente involucra la eliminación de la glándula en la que ha surgido. El presente caso constituye el séptimo publicado de esta entidad.Tumors of the salivary glands constitute an important field of oral and maxillofacial pathology. The majority of salivary gland neoplasms are benign, with malignant salivary tumors accounting for 15 to 32 percent. The most common site for salivary gland tumors is the parotid gland, accounting up to 80 percent of all cases. This article reports the pathologic picture in a case of sebaceous adenoma of the parotid gland. The tumor was composed of epithelial cells lining ducts and closely associated with broad areas of sebaceous differentiation. The growth pattern was predominantly cystic, with cavities filled with sebaceous material. Areas of oncocytic metaplasia were also seen. The presence of sebaceous glands in salivary neoplasms is frequent, however, and in spite of this, salivary neoplasms constituted partially or entirely of these cells are rarely observed. To the surgeon and pathologist, the major problem in dealing with sebaceous adenoma is the recognition of this rare entity, avoiding confusing with other more aggressive neoplasms. The treatment involves surgical excision. The addition of the current case to the previously published data brings the total number of parotid sebaceous adenoma to seven

Optimization of graphite morphology in mottled Nihard cast irons inoculated with feb and manufactured by centrifugal casting

The present research was focused on the identification of manufacturing factors that have an active influence on the graphite phase formation in Nihard cast irons inoculated with FeB, constituting the outer layer of duplex work rolls. These rolls are used in the finishing stands of hot-strip steel mills where the following are desired: (a) between 2.5 and 4 vol % of graphite; (b) homogeneous graphite distribution across the layer section; and, (c) a reasonable high number of graphite particles across the layer. The research methodology that followed consisted of the application of a saturated design of experiments (DOE), with seven factors, eight experiments, and resolution III. The analyzed responses obtained by quantitative metallographic techniques were: the volume fraction of graphite, Vv; the number of counts per unit area of graphite, NA; and the graphite morphology across the layer thickness. Increasing the addition of FeB from 6 to 10 kg/T reduced the graphite volume fraction and the count number, but had no influence on its morphology. However, an increase of the liquidus temperature from 1225–1230 to 1250–1255 °C, and an increase in the amount of SiCaMn added to the ladle from 0.3 to 0.6 kg/T produced the desired compact graphite morphology