Mechanical Stability in Crystalline Silicon Solar Cells

Mechanical stability of back contact solar cells deteriorates when holes (MWT, EWT) or grooves (TWT) are created in the wafer. These operations are essential for these structures so we found necessary to quantify the magnitude of this damage. A set of wafers with the EWT structure was produced and its mechanical strength measured by the Ring on Ring bending test. Other two sets of wafers with similar processes were prepared and tested to compare the effect of different fabrication steps on mechanical strength of the wafer. A numeric model was developed to analyse the data from the Ring on Ring test and a statistical study was carried out

Análisis termodinámico de un sistema para generar energía eléctrica a partir de la energía mecánica de un gas natural

The objective of this work is to design a system for generating electricity from the mechanical energy of a natural gas at high pressure. The main motivation for the development of the research is based on the need to detect by the natural gas distribution industry, where it is considered that the use of the mechanical energy of natural gas (flow energy and kinetic energy) can be used for the Electric power generation, through a turbo expander, and thus power the electromechanical components of a substation. In this way, energy consumption costs are reduced, which translates into unquestionable gains in energy efficiency. The methodology applied is based on the use of physical principles such as the conservation of mass and energy in a control volume. Likewise, the guidelines established in the guideline for the expression of measurement uncertainty allowed us to estimate an interval where the real value of the mechanical power generated at the output of the turboexpander is found. Based on experimental data in a natural gas distribution substation, the consolidated results allowed quantifying the average mechanical power at the inlet of a turboexpander (8155 W) and, in the typical situation where the turboexpander reduces its outlet pressure to 50% , an average mechanical power is generated at the output of the turboexpander equal to 4893 W, which translates into an efficiency of 40%. This research work allowed us to conclude that the design of a system for electric power generation is viable based on the thermodynamic and dimensional parameters associated with the natural gas distribution system, as well as the mechanical power that can be generated at the exit of a turboexpander.Este trabajo tiene por objetivo diseñar un sistema de generación de energía eléctrica a partir de la energía mecánica de un gas natural a alta presión. La motivación principal para el desarrollo de la investigación se fundamenta en la necesidad detectar por la industria de distribución de gas natural, donde se considera que el aprovechamiento de la energía mecánica del gas natural (energía de flujo y energía cinética) puede ser aprovechado para la generación de energía eléctrica, a través de un turbo expansor, y así alimentar los componentes electromecánicos de una subestación. De esta forma se disminuyen costos de consumo de energía lo que se traduce en incuestionables ganancias de eficiencia energética. La metodología aplicada se basa en la utilización de principios físicos como lo son la conservación de masa y energía en un volumen de control. De igual forma, lo lineamiento establecidos en la guía para la expresión de la incertidumbre de medición, permitió estimar un intervalo donde se encuentra el valor real de la potencia mecánica generada a la salida del turbo expansor. A partir de datos experimentales en una subestación de distribución de gas natural, los resultados consolidados permitieron cuantificar la potencia mecánica promedio en la entrada de un turbo expansor (8155 W) y, en la situación típica donde el turbo expansor reduce su presión de salida al 50%, se genera una potencia mecánica promedio a la salida del turbo expansor igual a 4893 W, lo que se traduce en una eficiencia de 40%. Este trabajo de investigación permitió concluir que el diseño de un sistema para generación de energía eléctrica es viable a partir de los parámetros termodinámicos y dimensionales asociadas al sistema de distribución de gas natural, así como la potencia mecánica que puede ser generada a la salida de un turbo expansor

Damage reduction of the laser drilling process on back contact solar cells by chemical treatment

Production of back contact solar cells requires holes generations on the wafers to keep both positive and negative contacts on the back side of the cell. This drilling process weakens the wafer mechanically due to the presence of the holes and the damage introduced during the process as microcracks. In this study, several chemical processes have been applied to drilled wafers in order to eliminate or reduce the damage generated during this fabrication step. The treatments analyzed are the followings: alkaline etching during 1, 3 and 5 minutes, acid etching for 2 and 4 minutes and texturisation. To determine mechanical strength of the samples a common mechanical study has been carried out testing the samples by the Ring on Ring bending test and obtaining the stress state in the moment of failure by FE simulation. Finally the results obtained for each treatment were fitted to a three parameter Weibull distributio

Crack origin and detection in thin cristallyne solar cells in a production line

In order to reduce cost and make up for the rising price of silicon, silicon wafers are sliced thinner and wider,eading to weaker wafers and increased breakage rates during fabrication process. In this work we have analysed different cracks origins and their effect on wafer’s mechanical strength. To enhance wafer’s strength some etching methods have been tested. Also, we have analysed wafers from different points of an entire standard production process. Mechanical strength of the wafers has been obtained via the four line bending test and detection of cracks has been tested with Resonance Ultrasonic Vibration (RUV) system, developed by the University of South Florida

Adipose tissue aging partially accounts for fat alterations in HIV lipodystrophy

Altres ajuts: European Regional Development Fund (FEDER).Lipodystrophy is a major disturbance in people living with HIV-1 (PLWH). Several systemic alterations in PLWH are reminiscent of those that occur in ageing. It is unknown whether the lipodystrophy in PLWH is the consequence of accelerated ageing in adipose tissue. We compared systemic and adipose tissue disturbances in PLWH with those in healthy elderly individuals (~80 y old). We observed similarly enhanced expression of inflammation-related genes and decreased autophagy in adipose tissues from elderly individuals and PLWH. Indications of repressed adipogenesis and mitochondrial dysfunction were found specifically in PLWH, whereas reduced telomere length and signs of senesce were specific to elderly individuals. We conclude that ageing of adipose tissue accounts only partially for the alterations in adipose tissues of PLWH

Tetradentate polyamines as efficient metallodrugs for Chagas disease treatment in murine model.

A series of tetraamine-based compounds was prepared, and their trypanocidal effects against Trypanosoma cruzi and cytotoxicity were determined through the determination of IC50 values. In vivo assays were performed in mice, where parasitaemia levels were quantified by fresh blood examination and the assignment of a cure was determined by polymerase chain reaction and reactivation of blood parasitaemia levels after immunosuppression. The mechanisms of action were elucidated at metabolic and ultra-structural levels, by 1H NMR, Fe-SOD inhibition and TEM studies. The high-selectivity indexes observed in vitro were the basis of promoting one of the tested compounds to in vivo assays. Compound 6 induced a remarkable decrease in the reactivation of parasitaemia after immunosuppression and curative rates of 33%. The experiments allowed us to select compound 6 as a promising candidate for treating Chagas disease, but a further high-level study should be considered to obtain an improved efficiency

Research on missed nursing care during the COVID-19 pandemic: A scoping review

COVID-19; Atenció d'infermeria perduda; Atenció al pacientCOVID-19; Atención de enfermería perdida; Atención al pacienteCOVID-19; Missed nursing care; Patient careAbstract Background: Missed nursing care is defined as care that is delayed, partially completed, or not completed at all. The scenario created by the COVID-19 pandemic may have influenced multifactorial determinants related to the care environment, nursing processes, internal processes, and decision-making processes, increasing missed nursing care. Aim: This scoping review aimed to establish the quantity and type of research undertaken on missed nursing care during the COVID-19 pandemic. Methods: This review was conducted following the Joanna Briggs Institute methodology for scoping reviews. We searched CINAHL, MEDLINE, Scopus, two national and regional databases, two dissertations and theses databases, a gray literature database, two study registers, and a search engine from November 1, 2019, to March 23, 2023. We included quantitative, qualitative, and mixed studies carried out in all healthcare settings that examined missed nursing care during the COVID-19 pandemic. Language restrictions were not applied. Two independent reviewers conducted study selection and data extraction. Disagreements between the reviewers were resolved through discussion or with an additional reviewer. Results: We included 25 studies with different designs, the most common being acute care cross-sectional survey designs. Studies focused on determining the frequency and reasons for missed nursing care and its influence on nurses and organizational outcomes. Linking Evidence to Action: Missed nursing care studies during the COVID-19 pandemic were essentially nurses-based prevalence surveys. There is an urgent need to advance the design and development of longitudinal and intervention studies, as well as to broaden the focus of research beyond acute care. Further research is needed to determine the impact of missed nursing care on nursing-sensitive outcomes and from the patient's perspective

Veneno para plagas: Una aproximación desde la antropología cognitiva sobre exposición laboral, efectos en salud y calidad de vida de los aplicadores de plaguicidas del sector informal rural

 Objetivo: Explorar las dimensiones culturales del concepto de exposición a plaguicidas, salud, efecto en salud y de calidad de vida en aplicadores de plaguicidas rurales del sector informal. Materiales y métodos: Estudio exploratorio, realizado en 6 municipios del Atlántico (Colombia), en el que participaron 44 informantes, durante 2010 y 2011. Se utilizó técnica cualitativa por listados libres y sorteo por montones. Se indagaron términos asociados a los conceptos de plaguicida, salud, efecto en salud y calidad de vida. Se aplicó un análisis de consenso con técnicas visuales, se realizó factorización de componentes principales y análisis dimensional con el programa ANTHROPAC v4.0. Resultados: La salud es relacionada con estar sano y tener vida; no identifican efectos secundarios; la calidad de vida la relacionan con salud, familia y trabajo. No se encontró consenso cultural respecto la salud, pero de la misma manera sobresale que el familiar no piensa nada sobre el plaguicida o que “fumigar es normal”. Existe consenso cultural en cuanto a: la exposición a plaguicidas y la toxicidad de algunos de ellos; el plaguicida pro- tege el cultivo de plagas y mata insectos pero también mata a otros que ayudan al control biológico. Hay consenso cultural respecto a la práctica previa del consumo de leche y agua de panela antes de fumigar.  Conclusión: El estudio sobre los significados, creencias, valores y prácticas de los trabaja- dores aplicadores de plaguicidas informales en la zona rural tiene una aproximación muy diferente a los trabajadores formales que tienen el mismo oficio. Se observaron creencias y valores que deben considerarse al momento de realizar políticas de salud ocupacional

Análisis Socio-Urbanístico de Cantabria. Volumen II: Análisis del Planeamiento.

Estudios de base para la redacción de las Normas Urbanísticas Regionales (NUR) de Cantabria.Este proyecto de investigación aplicada se ha realizado gracias al Convenio de Colaboración entre el Gobierno de Cantabria y la Universidad de Cantabria titulado “Análisis Socio-Urbanístico de Cantabria”

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection