Hydrogen desorption in SiGe films : a diffusion limited process

A model to explain the hydrogen desorption kinetics in SiGe alloys is presented. This is an extension of a previous desorption model of hydrogen from Si, that considers the presence of three dimer types in the surface in which hydrogen atoms tend to pair before the desorptionreaction.Surfacediffusion is included in the model. The comparison with experimental results shows that desorption is a diffusion limited process

Development of a universal sample controlled thermal analysis (SCTA) system for being used with any thermoanalytical instrument

The SCTA method implies to control the te mperature in such a way that the reaction rate changes with the time according to a function previously defined by the user. Constant Rate Thermal Analysis (CRTA) is one of the most commonly used SCTA methods and implies achieving a temperature profile at whic h the reaction rate remains constant all over the process at a value previously selected by the user. This method permits to minimize the influence of heat and mass transfer phenomena on the forward reaction. The scope of this work is to develop a universal CRTA temperat ure controller that could be adapted to any thermoanalytical device. The thermoanalytical signal is programmed to follow a preset linear trend by means of a conventiona l controller that at the time controls a second conventional temperature programmer that forces the temp erature to change for achieving the trend programmed for the thermoanalytical signal. Ex amples of the performa nce of this control system with a Thermobalance and a Thermomechanical Analyser (TMA) are given

Kinetic model for thermal dehydrochlorination of poly(vinyl chloride)

In this paper, a novel method for calculating degradation kinetics is presented. The method has been applied to the thermal dehydrochlorination of two different samples of PVC. It has been observed that this dehydrochlorination is complex and involves two different processes. A model that accounts for the entire dehydrochlorination is proposed. This model involves nucleation and growth and diffusion controlled mechanisms. The kinetic parameters are obtained from linear heating rate, isothermal and sample controlled thermal analysis experiments. Kinetic results obtained from the macroscopic thermal analysis measurements demonstrate the correlation between the kinetics of the thermal dehydrochlorination of PVC and the structure of this macromolecule.Junta de Andalucía TEP-03002Ministerio de Ciencia e Innovación MAT 2008-06619/MA

Mechanochemical preparation of BaTiO3-Ni nanocomposites with high dielectric constant

A mechanochemical procedure is proposed for an easy preparation of a BaTiO3-Ni composite in a single step. BaTiO3 and Ni powders available in the market are mixed by dry ball milling producing a decrease of particle size and an evenly distribution of both phases. In the sintered pellets the nickel particles are homogeneously distributed into the BaTiO3 matrix and isolated from others Ni particles. The dielectric constant of the composite is considerably higher than that of the barium titanate. Moreover, the temperature of the ferroelectric ↔ paraelectric transition of the BaTiO3-Ni composite here prepared is much lower than the one of the pure BaTiO3 single phase

Steam-enhanced calcium-looping performance of limestone for thermochemical energy storage: The role of particle size

Steam injection has been proposed to attenuate the decay of CaO reactivity during calcium looping (CaL) under operating conditions compatible with carbon capture and storage. However, it is yet unknown whether the perceived advantages granted by steam hold under the distinct operating conditions required for the integration of the CaL process as a thermochemical energy storage system in Concentrating Solar Power Plants (CaL-CSP). Here, we study the influence of steam in conditions compatible with a CaL-CSP scheme and assess its impact when injected only during one stage; either calcination or carbonation, and also when it is present throughout the entire loop. The results presented here demonstrate that steam boosts the CaO multicycle performance in a CO2 closed loop to attain residual conversion values similar to those achieved at moderate temperatures under inert gas. Moreover, it is found that the enhancement in multicycle activity is more pronounced for larger particles.España Ministerio de Economía y Competitividad-FEDER (contracts CTQ2017- 83602-C2-1-R and -2-R)Junta de Andalucía and Universidad de Sevilla (Programa Operativo FEDER Andalucía 2014–2020, projects P18-FR-1087 and US-1262507

LAB Bacteriocins Controlling the Food Isolated (Drug-Resistant) Staphylococci

Staphylococci are a group of microorganisms that can be often found in processed food and theymight pose a risk for human health. In this study we have determined the content of staphylococci in 7 different fresh goat-milk cheeses. These bacteria were present in all of them, ranging from 103 to 106 CFU/g based on growth on selective media. Thus, a set of 97 colonies was randomly picked for phenotypic and genotypic identification. They could be clustered by RAPD-PCR in 10 genotypes, which were assigned by 16S rDNA sequencing to four Staphylococcus species: Staphylococcus aureus, Staphylococcus chromogenes, S. simulans, and S. xylosus. Representative strains of these species (n = 25) were tested for antibiotic sensitivity, and 11 of them were resistant to at least one of the antibiotics tested, including erythromycin, amoxicillin-clavulanic acid and oxacillin. We also tested two bacteriocins produced by lactic acid bacteria (LAB), namely the circular bacteriocin AS-48 and the lantibiotic nisin. These peptides have different mechanism of action at the membrane level. Nevertheless, both were able to inhibit staphylococci growth at low concentrations ranging between 0.16–0.73μM for AS-48 and 0.02–0.23μM for nisin, including the strains that displayed antibiotic resistance. The combined effect of these bacteriocins were tested and the fractional inhibitory concentration index (FICI) was calculated. Remarkably, upon combination, they were active at the low micromolar range with a significant reduction of the minimal inhibitory concentration. Our data confirms synergistic effect, either total or partial, between AS-48 and nisin for the control of staphylococci and including antibiotic resistant strains. Collectively, these results indicate that the combined use of AS-48 and nisin could help controlling (pathogenic) staphylococci in food processing and preventing antibiotic-resistant strains reaching the consumer in the final products.This research was funded by the Spanish Ministry of Economy and Competitiveness (SAF2013-48971-C2-1-R project), including funds from the European Regional Development Fundings (ERDF) and the Research Group General (BIO160, UGR

Hamstring extensibility in female elite soccer players

El objetivo de este estudio fue evaluar la extensibilidad de la musculatura isquiosural en futbolistas femeninas de élite. Se realizó un estudio descriptivo transversal en una muestra de 75 jugadoras de élite de fútbol de cuatro categorías: Sub12 (n=20, edad: 11,42 ± 0,90 años), Sub15 (n=21, edad: 13,38 ± 1,50 años), Provincial (amateur) (n=15, edad: 17,13 ± 1,85 años), y Nacional (profesional) (n=20, edad: 22,80 ± 5,25 años). Como instrumentos de medición se utilizaron el test sit and reach (SRT) y el test de flexión profunda (FP) de tronco. Los valores medios presentados en el SRT fueron de 9,74 ± 5,62 cm. para el grupo Sub12, 13,86 ± 4,82 cm. para el grupo Sub15, 9,73 ± 3,58 cm para el grupo Provincial (amateur) y 7,55 ± 8,39 cm para el grupo Nacional (profesional). En el SRT las participantes del grupo Sub15 obtuvieron resultados significativamente superiores que las participantes del grupo Nacional (p<.05), mientras que en la prueba FP el grupo Sub12 obtuvo resultados significativamente superiores que el grupo Nacional (p<.05). En el análisis de correlaciones bivariadas, se observaron correlaciones moderadas entre la altura y los resultados en las pruebas de FP (r=.561; p<.05) y SRT (r=.491; p<.05) en el grupo Sub12. En conclusión, los resultados de este estudio indican que la extensibilidad isquiosural de las jugadoras de élite de fútbol estudiadas es limitada, por lo que deberíamos implementar programas específicos de estiramientos de la musculatura isquiosural en futbolistas féminas desde las categorías inferiores hasta las categorías profesionales. Palabras clave. flexibilidad, fútbol femenino, flexión profunda, sit and reach test.The aim of this study was to evaluate hamstring extensibility in female elite soccer players. A descriptive transversal study was carried out with a sample of 75 female elite soccer players into four categories: Under12 (n=20, age: 11,42 ± 0,90 years), Under15 (n=21, age: 13,38 ± 1,50 years), Provincial (amateur) (n=15, age: 17,13 ± 1,85 years), and National (professional) (n=20, age: 22,80 ± 5,25 years). The sit and reach test (SRT) and the deep trunk flexion test were used as measurement tools. The average values showed in the SRT were 9,74 ± 5,62 cm. for the Under12 group, 13,86 ± 4,82 cm. for the Under15 group, 9,73 ± 3,58 cm for the Provincial (amateur) group and 7,55 ± 8,39 cm for the National (professional) group. In the SRT the members of Under15 group showed significantly higher results than the members of National group (p<.05), while in the deep trunk flexion test the Under12 group showed significantly higher results than the National group (p<.05). In the analysis of bivariate correlations, in the Under12 group moderate correlations were observed between height and scores in the deep trunk test (r = .561; p <.05) and SRT (r = .491; p <.05). In conclusion, the results of this study indicate that the hamstring extensibility in female elite soccer players studied is limited, so we should implement stretching specific programs of the hamstring muscles in female soccer players from the lower categories to the professional categories. Key words. flexibility, female soccer, deep trunk, sit and reach test

The Federated Practice of Soccer Influences Hamstring Flexibility in Healthy Adolescents: Role of Age and Weight Status

The aim of this study was to compare the hamstring flexibility between federated soccer and non-federated adolescents, and also to evaluate the effect of age and weight status on hamstring flexibility. The participants were 234 students (11-18 years old) divided into: (i) G1: non-federated (n = 127), and (ii) G2: federated in soccer (n = 107). The deep flexion of the trunk (DF) test and the sit and reach test (SRT) were performed. G2 showed higher values for the DF and SRT compared to G1 (p < 0.05). Both flexibility tests correlated positively (r = 0.4, p < 0.001). Body mass index (BMI) was negatively correlated with the DF test (r = -0.3, p < 0.001), but not with the SRT. Divided by BMI, the underweight and normal weight groups had higher scores in the DF test compared with the overweight and obese groups (p < 0.001). BMI was negatively correlated with hamstring flexibility. Federated soccer students present higher scores of hamstring flexibility

A national data-based energy modelling to identify optimal heat storage capacity to support heating electrification

Heating decarbonisation through electrification is a difficult challenge due to the considerable increase in peak power demand. This research proposes a novel modelling approach that utilises easily accessible national-level data to identify the required heat storage volume in buildings to decrease peak power demand and maximises carbon reductions associated with electrified heating technologies through smart demand-side response. The approach assesses the optimal shifting of heat pump operation to meet thermal heating demand according to different heat storage capacities in buildings, which are defined in relation to the time (in hours) in which the heating demand can be provided directly from the heat battery, without heat pump operation. Ten scenarios (S) are analysed: two baselines (S1–S2) and eight load shifting strategies (S3–S10) based on hourly and daily demand-side responses. Moreover, they are compared with a reference scenario (S0), with heating currently based on fossil fuels. The approach was demonstrated in two different regions, Spain and the United Kingdom. The optimal heat storage capacity was found on the order of 12 and 24 h of heating demand in both countries, reducing additional power capacity by 30–37% and 40–46%, respectively. However, the environmental benefits of heat storage alternatives were similar to the baseline scenario due to higher energy consumption and marginal power generation based on fossil fuels. It was also found that load shifting capability below 4 h presents limited benefits, reducing additional power capacity by 10% at the national scale. The results highlight the importance of integrated heat storage technologies with the electrification of heat in highly gas-dependent regions. They can mitigate the need for an additional fossil-based dispatchable generation to meet high peak demand. The modelling approach provides a high-level strategy with regional specificity that, due to common datasets, can be easily replicated globally. For reproducibility, the code base and datasets are found on GitHub

Allium-Based Phytobiotic Enhances Egg Production in Laying Hens through Microbial Composition Changes in Ileum and Cecum

The misuse of antibiotics has led several countries to ban their use as prophylactics against bacterial diseases or as growth promoters in livestock and poultry. Phytobiotics (bioactive compounds extracted from plants) are one of the alternatives, due to their antimicrobial activity and its modulation of the gut microbiota and the improvement of productive properties. Garlic and onion extracts, rich in antimicrobial compounds, are of the most promising alternative to antibiotics. We supplemented a garlic- and onion-based product in the diet to laying hens at the beginning of their productive life. The group supplied with this product produced in one month more eggs and with bigger size. This increase in production was accompanied by changes in the bacterial community of the gut. These changes in the microbiota suggest an improvement in food digestibility, as the most important changes produced by these compounds occur in the most distal parts of the gut. The relative abundance of beneficial Lactococcus in the ileum and Lactobacillus in the cecum increased in the experimental group. Both genera are known to have beneficial effects on host. These results are very promising for the use of these compounds in poultry for short periods.Phytobiotics (bioactive compounds extracted from plants) are one of the explored alternatives to antibiotics in poultry and livestock due to their antimicrobial activity and its positive effects on gut microbiota and productive properties. In this study, we supplemented a product based on garlic and onion compounds in the diet to laying hens at the beginning of their productive life (from 16 to 20 weeks post-hatching). The experimental group showed a significant increase in the number of eggs laid and in their size, produced in one month compared to the control. This increase in production was accompanied by microbiota changes in the ileum and cecum by means of high throughput sequencing analyses. These bacterial shifts in the ileum were mainly the result of compositional changes in the rare biosphere (unweighted UniFrac), while in the cecum, treatment affected both majority and minority bacterial groups (weighted and unweighted UniFrac). These changes in the microbiota suggest an improvement in food digestibility. The relative abundance of Lactococcus in the ileum and Lactobacillus in the cecum increased significantly in the experimental group. The relative abundance of these bacterial genera are known to have positive effects on thSpanish Ministry of Science and Innovation, Consejería de Economía, Innovación, Ciencia y Empleo (Junta de Andalucía)University of Granada-CEI BioTic (Project No. P-BS-37)INTERCONECTA program (Spanish Ministry of Economy and Competitiveness