Analysis by Finite Element Calculations of Light Scattering in Laser-textured AZO Films for PV thin-film Solar Cells

In the thin-film photovoltaic industry, to achieve a high light scattering in one or more of the cell interfaces is one of the strategies that allow an enhancement of light absorption inside the cell and, therefore, a better device behavior and efficiency. Although chemical etching is the standard method to texture surfaces for that scattering improvement, laser light has shown as a new way for texturizing different materials, maintaining a good control of the final topography with a unique, clean, and quite precise process. In this work AZO films with different texture parameters are fabricated. The typical parameters used to characterize them, as the root mean square roughness or the haze factor, are discussed and, for deeper understanding of the scattering mechanisms, the light behavior in the films is simulated using a finite element method code. This method gives information about the light intensity in each point of the system, allowing the precise characterization of the scattering behavior near the film surface, and it can be used as well to calculate a simulated haze factor that can be compared with experimental measurements. A discussion of the validation of the numerical code, based in a comprehensive comparison with experimental data is include

Efecto del tiempo de espera en el matadero sobre el bienestar de corderos lechales

In this paper, the effect of lairage before slaughter on the welfare and carcass and meat quality in suckling lambs has been studied. Four lairage times have been evaluated, L0 no-lairage, L3 lairage of 3 h, L6 lairage of 6 h and L12 lairage of 12 h. Blood parameters, cortisol, creatine kinase (CK), lactate dehydrogenase (LDH), total protein and amyloid A protein, weight loss during lairage, carcass quality and meat pH in two longissimus and semitendinosus muscles have been studied. Lambs with a lairage of 12 hours showed higher level of cortisol, total protein and amyloid A protein, besides a greater live weight loss, indicating that had a higher stress response and further dehydration. The meat pH was higher in both muscles in the group L3. The lairage increased animal welfare concerns but not the quality of the meat.En este trabajo se estudia el efecto que el tiempo de espera antes del sacrificio tiene sobre el bienestar y la calidad de la canal y la carne en corderos lechales. Se han estudiado cuatro tiempos de espera, L0 sin periodo de espera, L3 espera de 3 h, L6 espera de 6 h y L12 espera de 12 h. Se han valorado parámetros sanguíneos, cortisol, creatin kinasa (CK), lactato deshidrogenasa (LDH), proteínas totales y proteína amiloide A, así como pérdidas de peso por la espera, calidad de la canal y la evolución del pH de la carne en dos músculos longissimus y semitendinosus. Los corderos que estuvieron esperando 12 h mostraron un mayor nivel de cortisol, proteínas totales y proteína amiloide A, además de tener una mayor pérdida de peso, lo que indica que tuvieron una mayor respuesta de estrés y mayor deshidratación. El pH de la carne fue más alto en los dos músculos para el grupo que estuvo esperando 3 h. El incremento de tiempo de espera afecta al bienestar del animal pero no a la calidad de la carn

New strategies in laser processing of TCOs for light management improvement in thin-film silicon solar cells

Light confinement strategies play a crucial role in the performance of thin-film (TF) silicon solar cells. One way to reduce the optical losses is the texturing of the transparent conductive oxide (TCO) that acts as the front contact. Other losses arise from the mismatch between the incident light spectrum and the spectral properties of the absorbent material that imply that low energy photons (below the bandgap value) are not absorbed, and therefore can not generate photocurrent. Up-conversion techniques, in which two sub-bandgap photons are combined to give one photon with a better matching with the bandgap, were proposed to overcome this problem. In particular, this work studies two strategies to improve light management in thin film silicon solar cells using laser technology. The first one addresses the problem of TCO surface texturing using fully commercial fast and ultrafast solid state laser sources. Aluminum doped Zinc Oxide (AZO) samples were laser processed and the results were optically evaluated by measuring the haze factor of the treated samples. As a second strategy, laser annealing experiments of TCOs doped with rare earth ions are presented as a potential process to produce layers with up-conversion properties, opening the possibility of its potential use in high efficiency solar cells

Activation of visible up-conversion luminescence in transparent and conducting ZnO:Er:Yb films by laser annealing

Transparent and conducting ZnO:Er:Yb thin films with visible up-conversion (660-nm emission under 980-nm excitation) were fabricated by RF magnetron sputtering. The as-deposited films were found to be transparent and conducting and the activation of the Er ions in these films to produce up-conversion luminescence was achieved by different post deposition annealing treatments in air, vacuum or by laser annealing using a Nd:YVO4 laser. The structural, electrical and optical properties and the up-conversion efficiency of these films were found to be strongly influenced by the annealing method, and a detailed study is reported in this paper. It has been demonstrated that, although the air annealing was the most efficient in terms of up-conversion, laser annealing was the only method capable of activating Er ions while preserving the electrical conductivity of the doped films. It has been shown that a minimum energy was needed in laser annealing to optically activate the rare earth ions in the ZnO host material to produce up-conversion. Up-converting and transparent conducting ZnO:Er:Yb films with an electrical resistivity of 5×10-2 Ω·cm and transparency ~80% in the visible wavelength range has been achieved by laser annealing

Bienestar animal de corderos ternascos durante su espera en matadero

El presente trabajo consistió en valorar la respuesta de estrés al que son sometidos los corderos desde que llegan al matadero hasta su sacrificio en distintas épocas del año, primavera y verano. Se tomaron muestras de sangre durante el sacrificio del animal para la valoración de diferentes parámetros sanguíneos de respuesta de estrés y tras el faenado se valoró la calidad de la canal y de la carne de los corderos. Se encontraron diferencias significativas con mayores valores para los corderos sacrificados en verano en el número de linfocitos, lactato deshidrogenasa (LDH), cortisol y pHs y menores en el número de leucocitos, neutrófilos, relación neutrófilos/linfocitos, volumen corpuscular medio, concentración de glucosa y rendimiento de la canal. Los corderos sacrificados en verano tuvieron más comprometido su nivel de bienestar por el mayor nivel de cortisol y LDH junto con unos pHs más elevados, lo que hace que la calidad de la carne sea inferior a los sacrificados en primavera

Efecto de la adicción de extracto de vino tinto en la conservación de hamburguesas de cordero enriquecidas en ácidos grasos omega-3

Red wine is a great source of polyphenols compounds, which exert a high antioxidant capacity. The effect of red wine extract (EV) on the oxidative stability of lamb patties in terms of metmyoglobin (MetMb) formation, lipid oxidation, protein oxidation, and the stability of docosahexaenoic fatty acid (DHA) was investigated. Ground lamb meat enriched in ω3 fatty acids was divided into four treatments. Three treatments were supplemented with 3 doses of EV being 50 (EV1), 100 (EV2) and 200 (EV3) mg GAE/kg meat and, the last one, without antioxidant supplementation, was kept as control (C). The lamb patties were stored under MAP (70% O2/30% CO2) during 9 days. There was an interaction between treatment (L) and storage period (PC) for MetMb proportion (p<0.001) and DHA content (p<0.01). Groups EV2 and EV3 showed less MetMb proportion and higher DHA content at the end of storage period in comparison to groups EV1 and C. Lipid and protein oxidation was affected by storage period (p<0.001), increasing in all treatments.El vino tinto es una gran fuente de compuestos polifenólicos que presentan una gran capacidad antioxidante. El objetivo de este estudio fue evaluar el efecto de la adición de extracto de vino (EV) en la estabilidad oxidativa de hamburguesas de cordero, estudiando la formación de metamioglobina (MetMb), la oxidación lipídica, la oxidación proteica y el contenido en ácido docosahexaenoico (DHA). Se realizaron 4 lotes de carne picada de cordero, todos enriquecidos en ácidos grasos ω3. A tres lotes se les adicionó EV para obtener una concentración final de 50 (EV1), 100 (EV2) y 200 (EV3) mg GAE/kg de carne y el último lote, sin antioxidantes, se mantuvo como control (C). Las hamburguesas se conservaron en MAP (70% O2/30% CO2) durante 9 días. Se observó una interacción entre el lote (L) y el periodo de conservación (PC) para la proporción de MetMb (p<0,001) y el contenido en DHA (p<0,01). Los lotes EV2 y EV3 presentaron menor proporción de MetMb y mayor contenido en DHA que los lotes EV1 y C. La oxidación lipídica y proteica estuvo afectada por el periodo de conservación (p<0,001) aumentando en todos los tratamientos

Efecto de la suplementación con antioxidantes en la dieta de corderos sobre la calidad de su carne enriquecida en ácidos grasos omega-3

Se ha evaluado el efecto antioxidante de la suplementación en la dieta de corderos con vitamina E o con extracto de uva rico en polifenoles en carne enriquecida en ácidos grasos omega-3 mediante la alimentación y conservada durante 0, 6 y 12 días en atmósfera modificada. Se observó una interacción significativa (p<0.001) entre el tipo de suplementación y el tiempo de conservación para los valores de oxidación lipídica y de proporción de metamioglobina, mostrando la carne suplementada con vitamina E los valores más bajos al final de la conservación. Los niveles de ácidos grasos poliinsaturados descendieron durante la conservación en el grupo control y en el grupo suplementado con extracto de uva, permaneciendo más estables en el grupo suplementado con vitamina E. Se observó una interacción significativa (p<0.001) entre la suplementación y el tiempo de conservación para el porcentaje de ácidos grasos omega- 3, manteniéndose los valores estables durante la conservación en la carne suplementada con vitamina E. La suplementación en la dieta con vitamina E mostró un efecto antioxidante en la carne durante su conservación mayor que el resto de dietas estudiadas

Investigation on the structural changes of ZnO:Er:Yb thin film during laser annealing to fabricate a transparent conducting upconverter

A transparent and conducting ZnO:Er:Yb thin film with upconversion properties has been achieved after being annealed with continuous laser radiation just before the ablation point of the material. This work demonstrates that the laser energy preserves the conductivity of the film and at the same time creates an adequate surrounding for Er and Yb to produce visible upconversion at 660, 560, 520, and 480 nm under 980 nm laser excitation. The relation between the structural, electrical and upconversion properties is discussed. It is observed that the laser energy melts part of the material, which recrystallizes creating rare earth oxides and two different wurtzite structures, one with substitutional rare earths and oxygen vacancies (responsible for the conductivity) and the other without substitutional rare earth ions (responsible for the upconversion emission)