Analysis of Solar Passive Techniques and Natural Ventilation Concepts in a Residential Building Including CFD Simulation

The European residential building sector accounts for over 40% of final energy consumption in the European Union member states. Therefore, an improvement of buildings energy efficiency represents a great instrument to reduce CO2 emissions. The first step to increase energy performance in buildings is to use passive strategies, such as orientation, natural ventilation or envelope optimisation. This paper presents an analysis of solar passive techniques and natural ventilation concepts in a case study: La Clota residential building, located near Barcelona (Spain). It has been carried out a comparative analysis of La Clota building in order to evaluate its energy and environmental performance with respect to a conventional building and also with respect to another hypothetic building with improved performance with respect to La Clota. Main tools used are energy dynamic simulation and, when necessary, CFD analysis in order to go into the effect of specific measures in depth. Accordingly, conclusions about the most effective energy measures are drawn, not only for this particular building, but also for other Mediterranean climate locations

Insight into the reversible structural crystalline-state transformation from MIL-53(Al) to MIL-68(Al)

The reversible crystalline transformation between MIL-53(Al) and MIL-68(Al) is described. This followed a uniform conversion model with cleavage and formation of metal-ligand bonds after exchange or removal of guest molecules. MIL-68(Al) materials produced during the transformations had higher thermal stability and crystallinity than the as-synthesized MIL-68(Al)

Identificación de errores conceptuales en la enseñanza de la biología en el Centro Regional Universitario de Veraguas.

Ante las circunstancias de la existencia de errores conceptuales en las estructuras cognitivas de los estudiantes, y la necesidad de identificarlos entre los estudiantes de la Carrera de Biología del Centro Regional Universitario de Veraguas, se propone la siguiente metodología de investigación- Identificar los errores conceptuales observados en estudiantes de biología del Centro Regional Universitario de Veraguas, utilizando instrumentos tipos cuestionarios, encuestas, entrevistas, revisión de contenidos y programas. La muestra seleccionada estuvo constituida por los estudiantes de la carrera de Biología del Centro Regional Universitario de Veraguas. El instrumento utilizado con los estudiantes fue elaborado por la autora y, luego, revisado por los profesores que dictan cursos en dicha carrera. El cuestionario tiene preguntas cerradas de opción múltiple; fue tabulada para determinar la persistencia de los errores conceptuales. Fueron consideradas respuestas sin error conceptual o satisfactorias aquellas en que el 75% o más de contestación fue en la respuesta correcta. En primer año hay 15 preguntas el porcentaje de respuesta fue mayor en las correctas De estas 15, una no tubo error conceptual; el porcentaje de respuesta correcta fue de 100%. En segundo año hubo dos preguntas que no presentaron un error conceptual. En tercer año hubo tres preguntas sin error conceptual, y una cuyo porcentaje fue de 100% en la respuesta correcta. En cuarto año dos preguntas no tuvieron error conceptual. En 25 preguntas, de las 27, se encontraron errores conceptúales al totalizar las respuestas dadas a cada alternativa por los estudiantes que respondieron el instrumento

Enhancement of growth of MOF MIL-68(Al) thin films on porous alumina tubes using different linking agents

The preparation of MIL-68(Al) films on the inner surface of alumina tubes is reported. As the direct deposition of the MOF on bare alumina gives poor adhesion results, three different linking agents are employed to achieve a good MOF–support interaction. Colloidal silica LUDOX®, zeolite silicalite-1, and natural polysaccharide chitosan are chosen as binders, because they contain potential functional groups (hydroxy, amino, ether), which can establish hydrogen bonds. While colloidal silica leads to noncontinuous MOF layers, silicalite-1 and chitosan give rise to uniform and well-anchored films, as confirmed by the different characterization techniques used to study the MOF layer. Single-gas permeation experiments are carried out to determine the quality and ideal efficiency of the membranes prepared with silicalite-1 and chitosan. The results for the MIL-68(Al)/silicalite-1 membranes evidence the existence of macrodefects. However, no cracks are found when chitosan is used as a linking agent, and the gas flow through the MIL-68(Al)/chitosan membranes clearly follows Knudsen diffusion

A comparative study between single gas and mixed gas permeation of polyether-block-amide type copolymer membranes

We analyze the gas separation performance of five polyether-block-amide type copolymers (Pebax® 1657, Renew®, 2533, 3533 and 4533). These codes are composed of different hard and rubbery segments with different proportions. Dense membranes were prepared by the casting-solution method and studied by elemental, thermogravimetric and X-ray diffraction analyses, FTIR-ATR spectroscopy and single and mixed gas permeation. Codes with the best separation performance are those of polyethylene oxide as the soft phase (Pebax® 1657 and Renew®) due to the more intense interactions of this segment with CO2, which increases the CO2/N2 solubility selectivity (17.5 and 30.5 for Pebax® 1657 and Renew®, respectively) and hence the CO2/N2 separation selectivity of the membrane (36 and 37 for Pebax® 1657 and Renew®, respectively, obtained from mixed gas permeation). It is also noticeable that the proportion of the soft phase in the copolymer determines the permeability of CO2. It was found that the codes with a greater soft/hard segment ratio (Pebax® 2533 and 3533) have also a greater permeability value (239 and 220 Barrer for Pebax® 2533 and 3533, respectively, measured by mixed gas permeation). Pebax® Renew® was the polymer with the best separation performance with CO2 permeabilities of 167 and 164 Barrer and CO2/N2 selectivities of 41 and 37, measured by single and mixed gas permeation, respectively. The comparison between the single and mixture gas permeation results revealed a relatively good correspondence between both for most of the Pebax® codes tuned by the solubility and diffusion properties of the polymers. © 2022 The Authors

Valoración de empresas: Barón de Ley y Bodegas Riojanas.

Con el objeto de realizar una valoración a dos empresas del sector vitivinícola a través de sus cuentas anuales, se han elegido las sociedades Barón de Ley y Bodegas Riojanas. Para llevar a cabo el estudio, se procederá a explicar brevemente el sector al que pertenecen e identificar las empresas seleccionadas. Posteriormente se centrará en el análisis contable de ellas, donde se hará el estudio del fondo de maniobra de la empresa, y de una serie de ratios de liquidez, de tesorería, de rentabilidad económica y de rentabilidad financiera, entre otros.Se tratan de dos bodegas que se dedican a la elaboración de diferentes tipos de vino, de las que analizaremos un análisis valorativo de dichas empresas, para obtener su valor y poder compararla con otras mediante diferentes métodos, entre los que se encuentran los que están basados en el balance, y dentro de él, en el valor contable, valor sustancial y CPNE. Otros métodos también utilizados son la cuenta de resultados, métodos mixtos y en el descuento de flujos de fondos, dando especial importancia a este último. Todos ellos intentan determinar el valor de la empresa mediante diferentes técnicas.Para finalizar, se compararán las valoraciones llevadas a cabo en ambas empresas con la que hace el mercado, y podremos extraer las pertinentes conclusiones.<br /

Nanosheets of MIL-53(Al) applied in membranes with improved CO 2 /N 2 and CO 2 /CH 4 selectivities

MIL-68(Al) and MIL-53(Al) are carboxylate-based metal-organic frameworks (MOFs) with the same chemical composition but different structures (polymorphs). In this study, MIL-53(Al) nanosheets of ca. 150 nm in size with an average thickness of 3.5 ± 0.9 nm were obtained after immersion of a sample composed of MIL-68(Al) and MIL-53(Al) in water under different conditions (ultrasound, stirring, reflux, 60 °C and room temperature). The disaggregated MIL-53(Al) nanosheets produced under more severe conditions were suspended in a PDMS solution and then deposited on asymmetric polyimide P84® supports under vacuum filtration to form supported mixed matrix membranes (MMMs). When applied to the separation of CO 2 /CH 4 and CO 2 /N 2 mixtures, the MMM with MIL-53(Al) nanosheets improved the CO 2 /CH 4 (28.4-28.7 vs. 22.4) and CO 2 /N 2 (19.9-23.2 vs. 17.5) selectivities of the conventional MIL-53(Al) MMM with higher CO 2 permeances (20.8-29.6 GPU vs. 9.5 GPU for CO 2 /CH 4 and 17.7-26.8 GPU vs. 11.2 GPU for CO 2 /N 2 )

Membrane Traffic and Muscle: Lessons from Human Disease

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73369/1/j.1600-0854.2008.00716.x.pd

Caffeine Encapsulation in Metal Organic Framework MIL-53(Al) at Pilot Plant Scale for Preparation of Polyamide Textile Fibers with Cosmetic Properties

Currently in the marketplace, we can find clothing items able to release skin-friendly ingredients while wearing them. These innovative products with high-added value are based on microencapsulation technology. In this work, due to its lightness, flexibility, porosity, chemical affinity and adsorption capacity, metal-organic framework (MOF) MIL-53(Al) was the selected microcapsule to be synthesized at a large scale and subsequent caffeine encapsulation. The synthesis conditions (molar ratio of reactants, solvents used, reaction time, temperature, pressure reached in the reactor and activation treatment to enhance the encapsulation capacity) were optimized by screening various scaling-up reactor volumes (from lab-scale of 40 mL to pilot plant production of 3.75 L). Two types of Al salts (Al(NO3)3·9H2O from the original recipe and Al2(SO4)3 as commercial SUFAL 8.2) were employed. The liporeductor cosmetic caffeine was selected as the active molecule for encapsulation. Caffeine (38 wt %) was incorporated in CAF@MIL-53(Al) microcapsules, as analyzed by TGA and corroborated by GC/MS and UV-vis after additive extraction. CAF@MIL-53(Al) microcapsules showed a controlled release of caffeine during 6 days at 25 °C (up to 22% of the initial caffeine). These capsules were incorporated through an industrial spinning process (with temperatures up to 260 °C) to manufacture PA-6 fibers with cosmetic properties. Up to 0.7 wt % of capsules were successfully incorporated into the fibers hosting 1700 ppm of caffeine. Fabrics were submitted to scouring, staining, and washing processes, detecting the presence of caffeine in the cosmetic fiber. © 2022 The Authors. Published by American Chemical Society

Tuning the separation properties of zeolitic imidazolate framework core-shell structures via post-synthetic modification

The conversion of ZIF-8 into ZIF-7 via post-synthetic modification with benzimidazole has been monitored by quantifying the liberated 2-methylimidazole by chromatography. The reaction kinetics have been adjusted to the shrinking core model, providing the diffusion coefficient of bIm inside the pores and the reaction kinetic constant (2.86 × 10-7 cm2 s-1 and 1.36 × 10-4 cm s-1, respectively). A wide variety of ZIF-7/8 hybrid core-shell frameworks have been obtained during this reaction. The most promising have been characterized by SEM/TEM, TGA, N2 and CO2 adsorption, FTIR and 13C NMR, showing features of the coexistence of both phases inside the frameworks. Their structures have also been simulated, providing comparable XRD and adsorption results. The hybrid material has been used as a filler for PBI mixed matrix membranes (MMMs) applied to H2/CO2 separation, enhancing the performances of the bare PBI polymer and MMMs containing ZIF-8 or ZIF-7 as a filler, with a maximum H2 permeability value of 1921 Barrer and a H2/CO2 selectivity of 11.8