El control del tratamiento superficial de los tapones de corcho

Es bien sabido que el corcho como material posee una serie de características que le hacen susceptible de múltiples aplicaciones industriales (ligereza, elasticidad, compresibilidad, impermeabilidad, elevado rozamiento, aislante térmico etc.) de las cuales la más importante es la fabricación de tapones para el embotellado de los mejores caldos. Esto no solamente se debe al punto de vista económico (por el valor añadido que aporta), sino a lo que representa culturalmente en el mundo del vino. Un buen comportamiento de los tapones en el proceso de encorchado, así como de su permanencia en botella hasta el destapado, está íntimamente ligado a una serie de características de naturaleza físico-mecánica inherentes al corcho, al riguroso y cuidado proceso de fabricación y, de forma muy importante, a los tratamientos superficiale

La predicción del calibre del corcho al final del turno y su aplicación al muestreo de la producción

105 cork samples (20 cm x 20 cm) have been extracted from seven sites selected as representatives of the main cork oak production areas in Spain. Age, thickness and annual growth of cork have been measured on the transversal section of each piece. Thickness of cork one, two and three years before stripping has been calculated. Lineal regression analysis has been performed to obtain predicting equations for thickness at debarking time, where independent variables were thickness one, two or three years before stripping and growth rate at each moment. A set of equations was obtained, and regression coefficients varied between 0.9918 (the year before stripping) and 0.9182 (three years before stripping). Due to the sampling method, it is considered that these equations can be applied all over the cork oak distribution area in Spain. Best results can be obtained using the following equation: EF = 0.70021 + 1.05232 * Et–1 (EF: final cork thickness; Et–1: cork thickness one year before stripping) The results allow some changes in the current sampling methods, designed for owners assessment, as sampling in the field can be done the year before stripping. Due to the role of thickness in grading of cork planks, more 75 % of the production is not affected by these estimations, when thickness one year before stripping is used.Se ha tomado una muestra de 105 piezas de corcho en plancha de 20 por 20 cm de tamaño, procedentes de siete puntos de muestreo localizados en montes que se consideran representativos de las principales zonas españolas de producción de corcho. Sobre la sección transversal de cada pieza se ha determinado la edad, y se han medido el espesor, o calibre, y los crecimientos anuales para cada uno de los años del turno, calculándose para cada pieza el espesor y crecimiento medio anual que presentaban uno, dos y tres años antes del descorche. Se realiza un análisis de regresión lineal paso a paso para ajustar las ecuaciones predictivas del espesor del corcho al final del turno, en función del espesor y el crecimiento medio anual uno, dos y tres años antes del descorche. Como resultado se obtiene una serie de ecuaciones en las que los coeficientes de determinación oscilan entre 0,9918 (un año antes del descorche) y 0,9182 (tres años antes del descorche). Debido a la amplitud del muestreo realizado y a la calidad de los ajustes, se considera que estas ecuaciones pueden ser aplicadas en cualquier punto del área española de producción de alcornocal. Los mejores resultados se obtienen con la ecuación: EF = 0,70021 + 1,05232 * Et–1 (EF: espesor final del corcho; Et–1: espesor el año anterior al descorche) Las ecuaciones obtenidas permiten modificar los actuales métodos de muestreo para asesoramiento de los propietarios, al posibilitar la toma de muestras uno, dos o tres años antes de la saca del corcho. Debido al papel que el espesor, tiene en el proceso de clasificación, se estima que un 75 % de la producción no estaría afectada por los errores que se puedan cometer en la estimación si se utilizan las ecuaciones basadas en el espesor el año antes del descorche

Estimación de la humedad de tapones de corcho mediante medida de la resistencia electrica

En este trabajo se exponen los resultados obtenidos en el Departamento de Productos Forestales del CIFOR-INIA sobre la relación entre la resistencia eléctrica y el contenido de humedad de los tapones de corcho. Estos resultados muestran que los medidores de humedad utilizados habitualmente en la industria pueden alcanzar una precisión elevada, siempre y cuando se tenga en cuenta la influencia de los distintos factores que afectan a la relación resistencia eléctrica-humedad: tipo de tapón, dirección de la medida, temperatura del material. Además, se han obtenido los modelos matemáticos que permiten la calibración de cualquier aparato de este tipo de manera rápida y sencill

The influence of the moisture content on the electrical resistance of two types of cork stoppers

The relationship between the log of the electrical resistance (ER; measured using pin electrodes) and the moisture content (MC) have not been reported in any form of cork. That is important for the cork stoppers industry because it should help in the design and verification of more precise devices for measuring cork moisture content. In this study, using linear regression techniques, different regression models of the type log(Log(R) + 1) = axh + b were derived to describe the relationship ERMC, that was measured using pin electrodes on two types of cork stoppers [natural (N) and agglomerate(AG)]. The results obtained show that in the models proposed, the moisture content of AG cork stoppers can be estimated with an error of ± 0.3%, while that of N stoppers can be estimated with an error of 0.5%. Neither the geographical origin of the N corks nor the surface treatment to which the AG corks were subjected significantly affected the proposed models. Therefore, the moisture content of cork stoppers could be measured at the industrial scale using electrical resistancetype moisture meter

Vortices in polariton OPO superfluids

This chapter reviews the occurrence of quantised vortices in polariton fluids, primarily when polaritons are driven in the optical parametric oscillator (OPO) regime. We first review the OPO physics, together with both its analytical and numerical modelling, the latter being necessary for the description of finite size systems. Pattern formation is typical in systems driven away from equilibrium. Similarly, we find that uniform OPO solutions can be unstable to the spontaneous formation of quantised vortices. However, metastable vortices can only be injected externally into an otherwise stable symmetric state, and their persistence is due to the OPO superfluid properties. We discuss how the currents charactering an OPO play a crucial role in the occurrence and dynamics of both metastable and spontaneous vortices.Comment: 40 pages, 16 figure

Data-Driven Phenotyping of Central Disorders of Hypersomnolence With Unsupervised Clustering

Background and ObjectivesRecent studies fueled doubts as to whether all currently defined central disorders of hypersomnolence are stable entities, especially narcolepsy type 2 and idiopathic hypersomnia. New reliable biomarkers are needed, and the question arises of whether current diagnostic criteria of hypersomnolence disorders should be reassessed. The main aim of this data-driven observational study was to see whether data-driven algorithms would segregate narcolepsy type 1 and identify more reliable subgrouping of individuals without cataplexy with new clinical biomarkers.MethodsWe used agglomerative hierarchical clustering, an unsupervised machine learning algorithm, to identify distinct hypersomnolence clusters in the large-scale European Narcolepsy Network database. We included 97 variables, covering all aspects of central hypersomnolence disorders such as symptoms, demographics, objective and subjective sleep measures, and laboratory biomarkers. We specifically focused on subgrouping of patients without cataplexy. The number of clusters was chosen to be the minimal number for which patients without cataplexy were put in distinct groups.ResultsWe included 1,078 unmedicated adolescents and adults. Seven clusters were identified, of which 4 clusters included predominantly individuals with cataplexy. The 2 most distinct clusters consisted of 158 and 157 patients, were dominated by those without cataplexy, and among other variables, significantly differed in presence of sleep drunkenness, subjective difficulty awakening, and weekend-week sleep length difference. Patients formally diagnosed as having narcolepsy type 2 and idiopathic hypersomnia were evenly mixed in these 2 clusters.DiscussionUsing a data-driven approach in the largest study on central disorders of hypersomnolence to date, our study identified distinct patient subgroups within the central disorders of hypersomnolence population. Our results contest inclusion of sleep-onset REM periods in diagnostic criteria for people without cataplexy and provide promising new variables for reliable diagnostic categories that better resemble different patient phenotypes. Cluster-guided classification will result in a more solid hypersomnolence classification system that is less vulnerable to instability of single features

Nitrogen sources on TPOMW valorization through solid state fermentation performed by Yarrowia lipolytica

This manuscript reports the valorization of two-phase olive mill waste (TPOMW) as raw material and carbon source for solid state fermentation using Yarrowia lipolytica as biocatalyst. Due to its chemical characteristics, a combination of different raw materials (TPOMW and wheat bran, WB) was evaluated and two distinct nitrogen sources were applied as supplementation for lipase production. A TPOMW/WB ratio of 1:1 and supplementation with ammonium sulfate was chosen as the best condition. The productivity in 24 h reached 7.8 U/gh and, after four days of process, only decreased about 35%. Process pH ranged from 5.5-5.9, remaining in an acid range. Thus, the successful use of TPOMW, a watery solid by-product with high content of lipids, as raw material for Yarrowia lipolytica growth and lipase production provided an environmental friendly alternative to valorize such waste.The authors kindly acknowledge the financial aid and research scholarships given by CAPES. Maria Alice Zarur Coelho thanks CNPq (Proc. 308890/ 2013-2)