Estimating a pressure dependent thermal conductivity coefficient with applications in food technology

In this paper we introduce a method to estimate a pressure dependent thermal conductivity coefficient arising in a heat diffusion model with applications in food technology. To address the known smoothing effect of the direct problem, we model the uncertainty of the conductivity coefficient as a hierarchical Gaussian Markov random field (GMRF) restricted to uniqueness conditions for the solution of the inverse problem established in Fraguela et al. Furthermore, we propose a Single Variable Exchange Metropolis-Hastings algorithm to sample the corresponding conditional probability distribution of the conductivity coefficient given observations of the temperature. Sensitivity analysis of the direct problem suggests that large integration times are necessary to identify the thermal conductivity coefficient. Numerical evidence indicates that a signal to noise ratio of roughly 1000 suffices to reliably retrieve the thermal conductivity coefficient

Cuestionando los relatos tradicionales: desigualdad, cambio liberal y crecimiento agrario en el Sur peninsular (1752-1901).

En este artículo analizamos los efectos de la Revolución Liberal en el campo andaluz y planteamos algunas hipótesis sobre la interacción entre la equidad en la distribución de la renta agraria, el aumento de la producción y sus efectos ambientales durante el siglo XIX. El análisis se realiza sobre un estudio de caso: Montefrío, situado en la provincia de Granada. En primer lugar analizamos la evolución de los usos del suelo y estimamos la producción agraria entre mediados del siglo XVIII y comienzos del siglo XX. Mostramos después los diferentes ritmos del crecimiento demográfico en este período y su interacción con los usos del suelo. A continuación se estudian los efectos de la reforma agraria liberal teniendo en cuenta la distribución de la propiedad de la tierra, pero también del ganado y del trabajo agrícola. Finalmente se evalúan las consecuencias sociales y ambientales en base a una serie de indicadores. El resultado permite señalar que a finales del siglo XIX tuvo lugar un claro deterioro de las condiciones de vida de la población a pesar de la mejor distribución de la propiedad de la tierra.In this article we analyse the effects of the Liberal Revolution in rural areas of Southern Spain. Several hypotheses are posited on the interaction among equity in the distribution of agricultural income, production and environmental effects during the 19th century. We focus on the case of Montefrío, located in the province of Granada. First, the evolution of land use is analysed and agricultural production is estimated between the mid‐18th and early 20th century. The varying rates of population growth in this period are shown as well as their interaction with land use. Then the effects of the liberal land reform are presented, taking into account the distribution of land ownership, livestock and agricultural work. Finally we assess social and environmental consequences using a series of indicators. As a result, it is clear that there was a deterioration in living conditions in the late 19th century despite the improved distribution of land ownership

Experiencia con WebCT en el curso 2003/04 en la Facultad de Ciencias Matemáticas

Depto. de Análisis Matemático y Matemática AplicadaInstituto de Matemática Interdisciplinar (IMI)Fac. de Ciencias MatemáticasTRUEpu

Motivational Factors in the Use of Videoconferences to Carry out Tutorials in Spanish Universities in the Post-Pandemic Period

Many of the tools used for virtual teaching during the pandemic had not been used previously, but they could continue to be used when traditional teaching returns. For this reason, this study focused on locating the key motivational factors for the possible continuation of the use of one of these tools, videoconferencing, to carry out tutorials in Spanish universities as a complement to face-to-face tutorials. For this, a literary review was conducted to obtain a list of motivational factors that may influence teachers to continuing using it, and a causal study was performed with university professors (through fuzzy cognitive maps) to identify the causal relationships among these factors and classify them by their relevance in making a decision. The most influential factors are intention, attitude and perceived compatibility with how tutorials are given, and the negative factors include quality management and trus

Identificación de la conductividad de un material cuando depende de la presión a la que está sometido

Depto. de Análisis Matemático y Matemática AplicadaInstituto de Matemática Interdisciplinar (IMI)Fac. de Ciencias MatemáticasTRUEpu

Modelling and simulation of heat and mass transfer for liquid type foods under high pressure processes

High Pressure (HP) Processing has turned out to be very effective in order to prolong the shelf life of some foods. This paper deals with the modelling and simulation of the effect of the combination of high pressure with thermal treatments on food. The behaviour and stability of this model are checked by various numerical examples. Furthermore, a simplified version of the model is presented and compared with the full model in terms of accuracy and computational time. The models developed provide a useful tool to design suitable industrial equipments and optimize the processes

Classification, composition and conservation status of fen habitats in NW Navarra, Spain

El estudio de 16 enclaves hidroturbosos del noroeste de Navarra (norte de España) ha constatado la variedad de estos ambientes en la Comunidad Foral de Navarra. De todos ellos, sólo uno (Xuriain) es genuinamente ombrógeno, predominando abrumadoramente los enclaves minerógenos. Su presencia está condicionada esencialmente por contactos geológicos entre rocas de recarga y litologías impermeables. Los análisis químicos de agua realizados muestran en general un pH ácido (entre 4,2 y 5,8) y una conductividad eléctrica baja, así como contenidos bajos en Ca2+ y Mg2+. De todos los enclaves estudiados, sólo cuatro (Arxuri, Belate, Baltsagorrieta y Gesaleta) deben ser considerados como turberas verdaderas, al poseer depósitos de turba superiores al metro de profundidad. El resto deben designarse como medios paraturbosos ya que sus depósitos son esencialmente minerales con presencia de turba nula o puntual. En cualquier caso, las condiciones tróficas y la vegetación hacen que los ambientes hidroturbosos navarros puedan asimilarse a formas de fen. La flora está compuesta por 432 taxones de cormófitos y briófitos. Se han reconocido 43 fitocenosis, a nivel de comunidad, variante o asociación, la mayor parte propias de los hábitats hidroturbosos; las más novedosas son la comunidad de Narthecium ossifragum y Sphagnum auriculatum, Erico tetralicis-Sphagnetum papillosi y Eriophoro angustifolii-Sphagnetum rubelli. El estado de conservación es variado, desde enclaves bien conservados hasta los profundamente modificados o alterados. Las principales agresiones son debidas a la ganadería. Se destaca la existencia de dos turberas prístinas (Baltsagorrieta y Gesaleta).The study of 16 mire sites in Northwestern Navarra (Northern Spain) has proved the diversity of these habitats in Navarra. Among them, just one (Xuriain) is genuinely ombrogenic, while minerogenic sites are the most abundant. Their occurrence is determined mainly by geological contacts between water retaining and non-permeable rocks. Chemical water analyses show mostly acid pH (4.2 – 5.8), low conductivity, and low Ca2+ and Mg2+ contents. Only four of the studied sites (Arxuri, Belate, Baltsagorrieta and Gesaleta) may be considered as true peat mires, bearing peat deposits over 1 m deep. The rest of sites are designed as para-peaty habitats, with essentially mineral deposits with peat absent or punctual. Anyway, trophic conditions and vegetation allow mires in Navarra to be assigned to fen forms. The flora is composed of 432 cormophytic and bryophytic taxa. 43 phytocoenosis have been recognized, down to community, variant or association level, most of them typical of mires; Narthecium ossifragum and Sphagnum auriculatum community, Erico tetralicis-Sphagnetum papillosi and Eriophoro angustifolii-Sphagnetum rubelli are the most outstanding novelties. Conservation status is varied, ranging from well preserved sites to deeply modified and altered ones. Main threats are caused by cattle managing. The existence of two pristine peat mires must be noted (Baltsagorrieta and Gesaleta)