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Environmentally-friendly tanning for leather production: a review
No full textTraditional industrial methods of the leather industry produce toxic chromium-containing wastewater and solid wastes, calling for alternative procedures. Here, we review greener technologies to produce leather with focus on principles to design materials, high-efficiency chrome tanning, chrome-free processes, e.g., organic tanning, combination tanning, nanomaterial-based tanning, and tanning agent-free technology, as well as high-performance post-tanning using multifunctional polymers, integrated tanning-dyeing systems, and socioeconomical aspects. High-efficiency chrome tanning is done by high-exhaustion chrome tanning or inverse chrome tanning, which reduce the usage of chrome. Organic tanning employs biomass-derived and polymeric tanning agents
Evaluating the efficiency, economics, and environmental impact of hybrid heat pumps assisted by biomass boilers for Spanish climate zones
Get PDFHybrid air-water heat pump systems combine the efficiency of the former with the boiler backup system when external conditions are unsuitable. For the rural domestic sector, the use of biomass boilers as backup also allows the sustainable use of local natural resources. The appropriate choice of size for both units is a complex decision that depends not only on demand and climate but also on other parameters, such as the storage tank and the control strategy. Specifically with biomass boilers, this choice has not been sufficiently addressed in the scientific literature. For this reason, a dynamic model of this hybrid scheme has been created, the analysis of which has been carried out with energy, environmental and economic indicators. This model has been applied to a single-family home in three areas in Spain with a higher demand for heating than cooling and with different efficiency standards, comparing different sizes of inverter heat pump with commercial features to cover the required demand together with the boiler. With all the reservations given by the variability of the case studies analyzed, it can be stated that the approximate value of a heat pump with a nominal capacity of 60–70 % of the peak demand of the house is the most cost-effective option as it obtains the best combined seasonal performance, reduced environmental impact, lower operating costs and in its life cycle. With this design, relevant participation of the boiler is assured, contributing to low unitary emissions and allowing the heat pump to operate at its best efficiency, also reducing its number of starts and stops. Parameters such as greater storage or a lower pump stop temperature also improve its performance, within limits close to the reference situation for Spain, also considering its prices for biomass and electricity consumed
Las bibliotecas escolares: equipamientos, servicios, colección, perfil profesional y modelos de gestión en la comunidad autónoma de Aragón (España)
Get PDFEn este artículo se realiza un análisis detallado sobre diversos aspectos de las bibliotecas escolares asentadas en la comunidad autónoma de Aragón, tales como los equipamientos, servicios, colección, perfil profesional de la persona responsable de la misma, y las diferentes modalidades de gestión que se observan en los centros educativos de la comunidad autónoma. La elaboración de este artículo se ha basado en la observación participante y en una exhaustiva revisión documental, en la que se han considerado estudios de referencia de gran importancia para Aragón. Tras analizar todos estos aspectos, se puede concluir que, en Aragón, aunque existen recomendaciones específicas que generalmente son seguidas por la mayoría de las bibliotecas escolares, los centros educativos disfrutan de una cierta autonomía y flexibilidad para adoptar diversas prácticas y modelos de gestión. Esto permite que puedan ofrecer servicios variados y de mayor calidad según los recursos económicos disponibles en cada centro, lo que genera una disparidad que podría corregirse a través de una distribución equitativa de los recursos por parte de las autoridades competentes
Calidad de los informes de cuidados de enfermería de unidades de soporte vital avanzado en la atención a población joven aragonesa en el año 2020
No full textHas the European Takeover Bids Directive reached its objectives? The cases of Finland, Germany and Spain
Get PDFInspired in the common law tradition, the European Takeover Bids Directive (TBD) aimed to promote an efficient market for corporate control in Europe by facilitating competition among acquirers in EU economies while protecting the rights of minority shareholders of listed companies. After more than 15 years from its transposition into European national regulations, in this paper we investigate whether the main objectives of the Directive have been achieved in three European countries representing the three legal families included under the Civil law regime: Spain, as a country belonging to the French Civil law tradition, Finland, which belongs to the Nordic law tradition and, finally, Germany as a country representing Germanic Civil law tradition. To perform an in-depth analysis, we did not use a sample of takeovers, but a hand-collected database covering all takeovers launched in Finland and Spain over the period 2000–2019, and in Germany over 2002–2019. The results obtained in our analysis lead us to be sceptical about the clear achievement of the objectives intended by the Directive in the three countries analysed. Although more openness to European bidders seems to have been reached in Spain and Finland, there is no evidence of an increase in intra-European cross border takeovers following the TBD’s transposition in any of the countries analysed. Moreover, the premiums paid to minority shareholders (proxy for their higher protection) have remained unchanged in Germany and have been reduced in Spain and Finland
Effects of a personalised, adapted computerised cognitive stimulation programme versus stimulating leisure activities in younger and older adults with mild or subjective cognitive impairment. Protocol for a randomised controlled trial
Get PDFBackground: Mild cognitive impairment represents a transitional stage between healthy aging and dementia, with subjective cognitive impairment being a key predictor of progression to dementia. This randomized controlled trial aims to compare the effectiveness of a personalized computerized cognitive stimulation program with that of stimulating leisure activities in younger and older adults with mild or subjective cognitive impairment. Methods: Participants aged ≥ 50 with mild cognitive impairment and subjective cognitive impairment or scores between 24 and 31 on the Spanish Mini-Mental State Examination were recruited. Exclusion criteria comprised living in residential care, use of acetylcholinesterase inhibitors, sensory impairments, agitation, or having received cognitive stimulation in the past 12 months. Fifty-nine community-dwelling individuals in Zaragoza, Spain, were randomly assigned to an two interventions group or a control group. The first intervention group will receive personalized computerized cognitive stimulation for 30 minutes per day, five days per week, while the second intervention group will participate in two to five stimulating leisure activities. The intervention will last eight weeks. The control group will receive the usual care for the same duration. The primary outcome is the assessment of global cognition; secondary outcomes include memory, verbal fluency, activities of daily living, and mood. Fundamento: El deterioro cognitivo leve representa una etapa de transición entre el envejecimiento saludable y la demencia; el deterioro cognitivo subjetivo es un predictor clave de esta progresión. Este ensayo controlado aleatorizado tiene como objetivo comparar la eficacia de un programa personalizado de estimulación cognitiva informatizada frente a la realización de actividades de ocio estimulantes en personas adultas jóvenes y mayores con deterioro cognitivo leve o deterioro cognitivo subjetivo. Métodos: Se reclutaron participantes ≥50 años con deterioro cognitivo leve, deterioro cognitivo subjetivo, o que obtuvieron puntuaciones de 24-31 pun-tos en el Mini-Examen Cognitivo de Lobo (versión de 35 puntos). Los criterios de exclusión incluyeron vivir en una residencia, tomar inhibidores de la acetilcolinesterasa, presentar alteraciones sensoriales, agitación o haber recibido estimulación cognitiva en los últimos 12 meses. Cincuenta y nueve personas residentes en la comunidad en Zaragoza, España, fueron asigna-das aleatoriamente a dos grupos de intervención o al grupo control. El primer grupo de intervención recibirá estimulación cognitiva informatizada personalizada durante 30 minutos/día, 5 días/semana mientras el segundo grupo de intervención participará en dos a cinco actividades de ocio estimulantes. La intervención durará ocho semanas. El grupo control recibirá la atención habitual durante el mismo periodo de tiempo. El resultado primario corresponde a la evaluación de la cognición global; los resultados secundarios comprenden mediciones de memoria, fluidez verbal, funcionamiento en actividades de la vida diaria y estado afectivo
An efficient numerical method for 1D singularly perturbed parabolic convection–diffusion systems with repulsive interior turning points
Get PDFIn this work, we propose and study a numerical method to solve efficiently one-dimensional parabolic singularly perturbed systems of convection–diffusion type, for which the convection coefficient is zero at an interior point of the spatial domain. We focus our attention on the case of having the same diffusion parameter in both equations; as well we assume adequate signs on the convective coefficients in order to the interior turning point is of repulsive type. Under these conditions, if the data of the problem are composed by continuous functions, the exact evolutionary solution, in general, has regular boundary layers at the end points of the spatial domain. To solve this type of problems, we combine the fractional implicit Euler method and the classical upwind scheme, defined on a special mesh of Shishkin type. The resulting numerical method reach uniform convergence of first order in time and almost first order in space. Numerical results obtained for different test problems are shown which corroborate in practice the uniform convergence of the numerical algorithm and also their computational efficiency in comparison with classical numerical methods used for the same type of problems
Male goats exposed to the “male-to-male effect” stimulate the reproductive activity and ensure high fertility of both does and male goats during the non-breeding season
No full textMale goats stimulated by the “male-to-male effect” for one month and then introduced to anestrous does are as efficient as those stimulated by photoperiod in inducing cyclicity in anestrous does. Here, we determined whether the sexually active (SA) male goats can stimulate reproduction in does and males when housed together in the same flock during the non-breeding season, and whether male goats exposed to the “male-to-male effect” can fertilize does with the same efficiency and timeframe as SA males stimulated by photoperiod. In March, one group of does was kept isolated from male goats, while three other groups were housed with seasonally hypoactive males (SH). In April, the isolated group was joined with two SA male goats (SA group), while the other three groups were managed as follows: one group was joined with two SA male goats (SA + SH group); the second group was joined with two SA male goats which were fitted with aprons to prevent mating (SA-apron + SH group); and the third group was joined with two SH male goats (SH + SH group). The percentages of does that kidded did not differ among SA (73 %), SA + SH (70 %) and SA-apron + SH (76)% groups; however, all three had greater kidding rates than the SH + SH group (29 %). We conclude that SA male goats stimulate the reproductive activity in both does and male goats during non-breeding season when housed together in the same group. Furthermore, male goats stimulated by the “male-to-male effect” can achieve fertility rates and fertilization timeframe comparable to those of SA male goats
Controlling carbonization of tannin for the effective Pd loading to hydrogenate lignin‐derived aldehydes
No full textFinding new catalytic applications for tannin, a biomass resource, exploiting its structural features and renewable nature, helps contribute toward carbon neutrality in catalysis. In this study, novel Pd‐supported, carbon‐neutral catalysts have been synthesized using tannic acid. First, tannic acid was cross‐linked and coated on the surface of nano‐SiO2. This material was then subjected to controllable carbonization, with the temperature being optimized, to obtain the catalyst support SiO2@TA‐T (T: carbonization temperature). Experimental results demonstrated that carbonizing at 400 °C remained part of the phenolic hydroxyls of tannin with satisfactory reducing ability. Meanwhile, the condensation and the deoxygenation of tannin increased the thermal stability of this support and introduced porous structures and abundant defect sites. This material was then used to adsorb and in situ reduce Pd2+ to develop Pd‐based catalysts. To this end, this synthesized Pd/SiO2@TA‐400 catalyst was then used to hydrogenate vanillin, with a conversion of 99% to vanillyl alcohol at a pressure of 0.5 MPa initial H2 and a temperature of 20°C for 60 min. Such remarkable results were corroborated in the hydrogenation of several lignin‐derived aromatic aldehydes, with our catalyst achieving high conversion and outstanding recyclability (5 recycles)