Mechanical degradation of composite structures subjected to environmental effects.

Polymeric materials have inherent advantages thanks to the mechanical properties that they lend to a structure enhancing its useful life in factors of safety, reliability and aesthetics. Nevertheless, the durability may be affected by other considerations including environmental attack resulting in unexpected failures and maintenance costs, making it therefore essential to accurately predict the overall performance of these structures. This study was designed to evaluate the joint strength of an adhesively bonded composite Single Lap Joint (SLJ), exposed to a hostile environment i.e. cycles of temperature and moisture, mechanical damage and fatigue. The aged joints under hygrothermal cycles were tested under static and dynamic loads. A combined experimental-numerical Cohesive Zone Model (CZM) was calibrated to predict the joint strength degradation, and damage propagation. The composite SLJ of T800/M21 bonded with FM94 was subjected to hygrothermal cycles in an environmental chamber (maximum 70 °C and minimum - 20 °C), at maximum 85 % Relative Humidity (RH). The results showed that the strength degraded consequent to the increasing number of cycles. The strength reduced by 42 % under static load after 714 cycles in comparison to unaged joints. The fatigue life was evaluated at 30%, 40% and 45% ultimate static load to a maximum of one million cycles, resulting in a continuous fatigue life reduction with the increase in the number of aging cycles. A characterisation of the moisture diffusion parameters was performed on adhesive (FM94) and composite laminate (T800/M21) subjected to hygrothermal cycles. A displacement-diffusion analysis was conducted to determine the effect of moisture on the elasticity of the adhesive. The displacement-diffusion model results and shear lap test results were employed to establish the degradation parameters of the CZM, thus predicting the degradation of the joint with an accuracy of 13 % at 714 hygrothermal cycles.PhD in Manufacturin

Effect of hygrothermal cycles on mechanical performance of composite adhesively bonded joints

This paper numerically and experimentally studied mechanical performance of composite adhesively bonded single-lap joints in the presence of hygrothermal cycles, under static tensile loading. Joint performance was predicted by the development of a coupled experimental-numerical approach based on cohesive zone modelling. Composite adherends of aerospace grade carbon fibre-reinforced Hexply® M21/T800 pre-impregnated plies, bonded using a 25mm × 25mm bond overlap. Bond interface was exposed to cyclic moisture and temperature loads by introduction of 2mm sharp cracks at joint runouts. Pre-cracked joint specimens were subjected to hygrothermal cycles in environmental chamber under conditions representative of aircraft operational cycles. Testing proved that joint degradation occurred with increased cycle numbers. Strength reduced by 42% under static load after 714 cycles compared to unaged joints. Degradation accelerated in the initial 84 cycles, but was reduced for higher cycles attributed to adhesive bulk moisture saturation. Moisture diffusion parameters were characterised for both adhesive and composite subjected to hygrothermal cycles. Adhesive reached moisture saturation level of 1.54%wt, while composite laminate was 0.68%wt. In both cases, moisture diffusion followed Fick's second law. Displacement-diffusion analysis determined effect of moisture on elasticity of adhesive. This analysis plus the single-lap test data were coupled to develop degradation parameters required for CZM, demonstrating an 87% accuracy at 714 hygrothermal cycles

Metodología para el diseño de un módulo de acumulación térmica usando materiales de cambio de fase (PCM) para un secador solar de túnel

El creciente interés en las energías renovables ha abierto una oportunidad para aplicar esta tecnología en la industria y el sector nacional. Sin embargo, en sistemas basados en energía solar, las limitaciones asociadas con la entrega de energía intermitente pueden causar un rendimiento inestable y diseños poco confiables. Las fluctuaciones climáticas, como la velocidad del viento y la apariencia de las nubes, se consideran los principales factores que contribuyen a la inestabilidad en la cantidad de energía disponible. En la agricultura, por ejemplo, el uso de la energía solar térmica aplicada a los sistemas de secado es altamente deseable ya que el proceso es energéticamente intensivo. Por lo tanto, es factible diseñar dispositivos de secado para productos agrícolas, con retornos económicos importantes debido al ahorro de energía y al valor agregado de los materiales procesados. Por lo tanto, el rendimiento energético de los sistemas que funcionan con energía solar térmica se puede mejorar mediante la introducción de un sistema de acumulación de energía basado en el uso de materiales de cambio de fase (PCM). Se presenta la metodología detallada para el diseño de un sistema de acumulación de energía térmica para un secador de túnel tipo Hohenheim para productos agrícolas. Como PCM, se elige parafina porque su temperatura de fusión es cercana a 60 ° C, que es un valor apropiado para la temperatura de secado de este tipo de productos. Los cálculos teóricos muestran que el valor de la temperatura superficial tiene una influencia importante en los cálculos de cambio de fase y la masa total de PCM requerida en el sistema. Por otro lado, la transferencia de calor está dominada por la transferencia de calor externa en el aire. Además, el diámetro del tubo afecta significativamente el tiempo de cambio de fase. Los resultados obtenidos son importantes y aportan una contribución significativa al conocimiento requerido para implementaciones de sistemas similares, ya que se ha explorado poco en este campo en regiones donde las condiciones climáticas son adecuadas para cambios inesperados. El diseño debe implementarse en un prototipo experimental de secador Hohenheim y su rendimiento debe determinarse en función de la medición del cambio de energía del aire de secado.The increasing interest in renewable energy has opened an opportunity to apply this technology in the industry and domestic sector. However, in solar-based systems, limitations associated with the intermittent energy delivery can cause unstable performance and unreliable designs. Weather fluctuations, such as wind speed and appearance of clouds, are considered the principal factors that contribute to the instability in the amount of energy available. In the agriculture, for instance, the use of thermal solar energy applied to dryer systems is highly desirable since the process is energetically very intensive. Therefore, it is feasible to design dryer devices for agricultural products, with important economic returns due to energy savings and the value added to the materials processed.  Thus, the energy performance of systems that operate with solar thermal energy can be improved by introducing an energy accumulation system based on the use of phase change materials (PCM). The detailed methodology for the design of a thermal energy accumulation system for a tunnel dryer type Hohenheim for agricultural products is presented.  As PCM, paraffin is chosen because its melting temperature is near 60 °C, which is an appropriate value for the drying temperature of this kind of products.  The theoretical calculations show that the value of the surface temperature has an important influence on phase change calculations and the total mass of PCM required in the system. On the other hand, the heat transfer is dominated by the external heat transfer in the air.  Additionally, the tube diameter significantly affects the phase change time. The results obtained are important and make a significant contribution to the knowledge required for implementations of similar systems, since little has been explored in this field in regions where the weather conditions are suitable to unexpected changes. The design should be implemented in an experimental prototype of Hohenheim dryer and its performance is to be determined based on measurement of the energy change of the drying air.&nbsp

Significance of the particle physical properties and the Geldart group in the use of correlations for the prediction of minimum fluidization velocity of biomass–sand binary mixtures

The present study explores the relevance of the physical properties of biomass particles on the determination of the minimum fluidization velocity (U-mf) of binary mixtures. Fluidization experiments were performed in a cold flow unit with diverse biomasses mixed with sand in different mass fractions. Gas velocity and pressure drop across the bed were used to determine U-mf. Different correlations reported in the literature were evaluated on their ability to accurately predict U-mf of the mixtures. Results showed satisfactory predictions when appropriately identifying correlations according to the corresponding Geldart groups for the biomass particles. This perspective opens new possibilities toward the generalization of correlation factors and helps in improving the accuracy of the prediction for highly heterogeneous mixtures. The methodology also allows the analysis of mixtures for which the experimental approach is difficult, such as those including char particle, with the only requirement of carefully measuring the physical properties of the particles

Sistema de Gestión de Seguridad y Salud en el Trabajo En Consorcio Hospital

120 hImplementar un Sistema de Gestión de la Seguridad y Salud en el Trabajo por medio de un proceso lógico y por etapas, basado en la mejora continua para anticipar, reconocer, evaluar y controlar los riesgos que puedan afectar la seguridad y la salud en el trabajo en el Consorcio Hospital del municipio del Retorno en el departamento del Guaviare. Realizar un análisis de la documentación administrativa de la empresa Consorcio Hospital. Realizar un diagnóstico del SG-SST y análisis sociodemográfico y de percepción frente a la salud de los trabajadores del Consorcio Hospital. Diseñar un plan de emergencias inicial. Realizar una matriz de evaluación del riesgo y valorización del peligro. Establecer un análisis de las tareas críticas. Generar un informe de capacitación a la empresa Consorcio Hospital Elaborar un plan anual y mensual en Seguridad y Salud en el Trabajo de la empresa Consorcio Hospital.Resultado para Obtener el Título de Profesional en Salud Ocupacional, Tesis (Profesional en Salud Ocupacional) Universidad de los Llanos Convenio Universidad del Tolima. Programa de Salud Ocupacional. Ceres San Jose del Guaviare- Meta., 2016EspecializaciónEspecializaciones en Seguridad y Salud en el Trabaj

Metodología para el diseño de un módulo de acumulación térmica usando materiales de cambio de fase (PCM) para un secador solar de túnel

El creciente interés en las energías renovables ha abierto una oportunidad para aplicar esta tecnología en la industria y el sector nacional. Sin embargo, en sistemas basados en energía solar, las limitaciones asociadas con la entrega de energía intermitente pueden causar un rendimiento inestable y diseños poco confiables. Las fluctuaciones climáticas, como la velocidad del viento y la apariencia de las nubes, se consideran los principales factores que contribuyen a la inestabilidad en la cantidad de energía disponible. En la agricultura, por ejemplo, el uso de la energía solar térmica aplicada a los sistemas de secado es altamente deseable ya que el proceso es energéticamente intensivo. Por lo tanto, es factible diseñar dispositivos de secado para productos agrícolas, con retornos económicos importantes debido al ahorro de energía y al valor agregado de los materiales procesados. Por lo tanto, el rendimiento energético de los sistemas que funcionan con energía solar térmica se puede mejorar mediante la introducción de un sistema de acumulación de energía basado en el uso de materiales de cambio de fase (PCM). Se presenta la metodología detallada para el diseño de un sistema de acumulación de energía térmica para un secador de túnel tipo Hohenheim para productos agrícolas. Como PCM, se elige parafina porque su temperatura de fusión es cercana a 60 ° C, que es un valor apropiado para la temperatura de secado de este tipo de productos. Los cálculos teóricos muestran que el valor de la temperatura superficial tiene una influencia importante en los cálculos de cambio de fase y la masa total de PCM requerida en el sistema. Por otro lado, la transferencia de calor está dominada por la transferencia de calor externa en el aire. Además, el diámetro del tubo afecta significativamente el tiempo de cambio de fase. Los resultados obtenidos son importantes y aportan una contribución significativa al conocimiento requerido para implementaciones de sistemas similares, ya que se ha explorado poco en este campo en regiones donde las condiciones climáticas son adecuadas para cambios inesperados. El diseño debe implementarse en un prototipo experimental de secador Hohenheim y su rendimiento debe determinarse en función de la medición del cambio de energía del aire de secado.The increasing interest in renewable energy has opened an opportunity to apply this technology in the industry and domestic sector. However, in solar-based systems, limitations associated with the intermittent energy delivery can cause unstable performance and unreliable designs. Weather fluctuations, such as wind speed and appearance of clouds, are considered the principal factors that contribute to the instability in the amount of energy available. In the agriculture, for instance, the use of thermal solar energy applied to dryer systems is highly desirable since the process is energetically very intensive. Therefore, it is feasible to design dryer devices for agricultural products, with important economic returns due to energy savings and the value added to the materials processed.  Thus, the energy performance of systems that operate with solar thermal energy can be improved by introducing an energy accumulation system based on the use of phase change materials (PCM). The detailed methodology for the design of a thermal energy accumulation system for a tunnel dryer type Hohenheim for agricultural products is presented.  As PCM, paraffin is chosen because its melting temperature is near 60 °C, which is an appropriate value for the drying temperature of this kind of products.  The theoretical calculations show that the value of the surface temperature has an important influence on phase change calculations and the total mass of PCM required in the system. On the other hand, the heat transfer is dominated by the external heat transfer in the air.  Additionally, the tube diameter significantly affects the phase change time. The results obtained are important and make a significant contribution to the knowledge required for implementations of similar systems, since little has been explored in this field in regions where the weather conditions are suitable to unexpected changes. The design should be implemented in an experimental prototype of Hohenheim dryer and its performance is to be determined based on measurement of the energy change of the drying air.&nbsp

La imagen y la narrativa como herramientas para el abordaje psicosocial en escenarios de violencia.

La violencia se puede interpretar como el acto realizado por algunos individuos para hacerles daño a otras personas con el fin de obtener o imponer algo. Este acto se realiza a través de la fuerza, las agresiones verbales y físicas dejando como consecuencias grandes daños económicos físicos o psicológicos en quienes la padecen. Colombia es un país que ha tenido que vivir por mucho tiempo con el conflicto armado. Esta problemática ha dejado grandes daños psicológicos y físicos en personas inocentes que tuvieron que enfrentarse a este suplicio de la guerra. Tal es el caso de Carlos Girón, una historia tomado del libro: Voces: Relatos de violencia y esperanza en Colombia, editado por el Banco mundial en el año 2009, sobre historias reales en el marco del conflicto armado. Carlos es un sobreviviente del conflicto armado quién con apenas 14 años fue víctima de un artefacto explosivo que le perjudico gran parte de su cuerpo. A pesar de todo lo sucedido él desea salir adelante y poderle ayudar a personas que han pasado por situaciones similares a la de él. Lo primero que se presentará en este documento, es el análisis “relatos de violencia y esperanza”. En el mismo se analizan los impactos psicosociales que se le observaron en este caso. Además se identifican las voces que revelan un posicionamiento subjetivo desde el lugar de víctima o sobreviviente, entre otros. Posteriormente se plantean preguntas de tipo estratégica, circular y reflexiva que representan gran relevancia en la comprensión del relato elegido y el establecimiento de posibles mecanismos de ayuda psicosocial en torno a este. Además, se aborda el caso de las comunidades de Cacarica, con el cual se identifican emergentes e impactos psicosociales hallados en el mismo y se establecen acciones de apoyo e intervención en crisis que fortalezcan el proceso de atención y acompañamiento a las víctimas en busca de potenciar sus recursos de afrontamiento y resiliencia. Para concluir, se presenta un informe analítico y reflexivo de la experiencia de la foto voz, que se realizó a partir de las experiencias que tuvieron los cinco integrantes del grupo colaborativo en sus comunidades. La foto Voz es una herramienta de gran importancia a la hora de intervenir en comunidades y con víctimas del conflicto armado, ya que esta ayuda a expresar y liberar sentimientos a partir de las imágenes. La intervención psicosocial con víctimas busca lograr la reparación y mitigar los daños psicológicos que les ha dejado la guerra a las víctimas del conflicto. Para esto el profesional que va a intervenir en estas comunidades debe tener las capacidades humanas y los conocimientos necesarios para poder brindar un adecuado acompañamiento psicosocial. Por otro lado, el enfoque narrativo es una herramienta que está dirigida a funcionarios que trabajan con víctimas. Está herramienta aporta grandes elementos para transformar las historias de victimización, dolor, miedo, culpa y rabia, en historias esperanzadoras y de sobrevivencia. Con la misma herramienta se busca desarrollar en las personas su capacidad de resiliencia para que logren verse como sobrevivientes sobreponiéndose a los períodos de dolor emocional y traumas. Además busca que las víctimas se adapten y superen positivamente las situaciones adversas estableciendo claramente sus proyectos de vida.Violence can be interpreted as the act performed by some individuals to harm other people in order to obtain or impose something. This act is carried out through force, verbal and physical aggressions, leaving as a consequence great physical or psychological economic damages in those who suffer it. Colombia is a country that has had to live for a long time with the armed conflict. This problem has left great psychological and physical damage to innocent people who had to face this ordeal of war. Such is the case of Carlos Giron, a story taken from the book: Voices: Stories of violence and hope in Colombia, edited by the World Bank in 2009, on real stories in the context of the armed conflict. Carlos is a survivor of the armed conflict who, at the age of 14, was the victim of an explosive device that damaged a large part of his body. In spite of everything that happened, he wants to get ahead and be able to help people who have gone through situations similar to his. The first thing that will be presented in this document is the analysis "stories of violence and hope". In it, the psychosocial impacts that were observed in this case are analyzed. In addition, the voices that reveal a subjective positioning from the place of victim or survivor, among others, are identified. Subsequently, questions of a strategic, circular and reflexive type are raised, which represent great relevance in the understanding of the chosen story and the establishment of possible psychosocial help mechanisms around it. In addition, the case of the communities of Cacarica is addressed, with which emergent and psychosocial impacts found in it are identified and support and intervention actions are established in crisis that strengthen the process of attention and accompaniment to the victims in search of strengthening your coping and resilience resources. To conclude, an analytical and reflective report of the photo voice experience is presented, which was made based on the experiences of the five members of the collaborative group in their communities. The photo Voice is a tool of great importance at the time of intervening in communities and with victims of the armed conflict, since this helps to express and release feelings from the images Psychosocial intervention with victims seeks to achieve reparation and mitigate the psychological damage that the war has left to the victims of the conflict. For this the professional who is going to intervene in these communities must have the human capacities and the necessary knowledge to be able to offer an adequate psychosocial accompaniment. On the other hand, the narrative approach is a tool that is aimed at officials who work with victims. This tool provides great elements to transform the stories of victimization, pain, fear, guilt and anger, into hopeful and survival stories. The same tool seeks to develop in people their resilience capacity so that they can be seen as survivors overcoming periods of emotional pain and traumas. It also seeks that victims adapt and overcome positive situations adversely by clearly establishing their life project

Burden of injury along the development spectrum : associations between the Socio-demographic Index and disability-adjusted life year estimates from the Global Burden of Disease Study 2017

Background The epidemiological transition of non-communicable diseases replacing infectious diseases as the main contributors to disease burden has been well documented in global health literature. Less focus, however, has been given to the relationship between sociodemographic changes and injury. The aim of this study was to examine the association between disability-adjusted life years (DALYs) from injury for 195 countries and territories at different levels along the development spectrum between 1990 and 2017 based on the Global Burden of Disease (GBD) 2017 estimates. Methods Injury mortality was estimated using the GBD mortality database, corrections for garbage coding and CODEm-the cause of death ensemble modelling tool. Morbidity estimation was based on surveys and inpatient and outpatient data sets for 30 cause-of-injury with 47 nature-of-injury categories each. The Socio-demographic Index (SDI) is a composite indicator that includes lagged income per capita, average educational attainment over age 15 years and total fertility rate. Results For many causes of injury, age-standardised DALY rates declined with increasing SDI, although road injury, interpersonal violence and self-harm did not follow this pattern. Particularly for self-harm opposing patterns were observed in regions with similar SDI levels. For road injuries, this effect was less pronounced. Conclusions The overall global pattern is that of declining injury burden with increasing SDI. However, not all injuries follow this pattern, which suggests multiple underlying mechanisms influencing injury DALYs. There is a need for a detailed understanding of these patterns to help to inform national and global efforts to address injury-related health outcomes across the development spectrum.Peer reviewe

Adolescent transport and unintentional injuries: a systematic analysis using the Global Burden of Disease Study 2019

Background: Globally, transport and unintentional injuries persist as leading preventable causes of mortality and morbidity for adolescents. We sought to report comprehensive trends in injury-related mortality and morbidity for adolescents aged 10–24 years during the past three decades. Methods: Using the Global Burden of Disease, Injuries, and Risk Factors 2019 Study, we analysed mortality and disability-adjusted life-years (DALYs) attributed to transport and unintentional injuries for adolescents in 204 countries. Burden is reported in absolute numbers and age-standardised rates per 100 000 population by sex, age group (10–14, 15–19, and 20–24 years), and sociodemographic index (SDI) with 95% uncertainty intervals (UIs). We report percentage changes in deaths and DALYs between 1990 and 2019. Findings: In 2019, 369 061 deaths (of which 214 337 [58%] were transport related) and 31·1 million DALYs (of which 16·2 million [52%] were transport related) among adolescents aged 10–24 years were caused by transport and unintentional injuries combined. If compared with other causes, transport and unintentional injuries combined accounted for 25% of deaths and 14% of DALYs in 2019, and showed little improvement from 1990 when such injuries accounted for 26% of adolescent deaths and 17% of adolescent DALYs. Throughout adolescence, transport and unintentional injury fatality rates increased by age group. The unintentional injury burden was higher among males than females for all injury types, except for injuries related to fire, heat, and hot substances, or to adverse effects of medical treatment. From 1990 to 2019, global mortality rates declined by 34·4% (from 17·5 to 11·5 per 100 000) for transport injuries, and by 47·7% (from 15·9 to 8·3 per 100 000) for unintentional injuries. However, in low-SDI nations the absolute number of deaths increased (by 80·5% to 42 774 for transport injuries and by 39·4% to 31 961 for unintentional injuries). In the high-SDI quintile in 2010–19, the rate per 100 000 of transport injury DALYs was reduced by 16·7%, from 838 in 2010 to 699 in 2019. This was a substantially slower pace of reduction compared with the 48·5% reduction between 1990 and 2010, from 1626 per 100 000 in 1990 to 838 per 100 000 in 2010. Between 2010 and 2019, the rate of unintentional injury DALYs per 100 000 also remained largely unchanged in high-SDI countries (555 in 2010 vs 554 in 2019; 0·2% reduction). The number and rate of adolescent deaths and DALYs owing to environmental heat and cold exposure increased for the high-SDI quintile during 2010–19. Interpretation: As other causes of mortality are addressed, inadequate progress in reducing transport and unintentional injury mortality as a proportion of adolescent deaths becomes apparent. The relative shift in the burden of injury from high-SDI countries to low and low–middle-SDI countries necessitates focused action, including global donor, government, and industry investment in injury prevention. The persisting burden of DALYs related to transport and unintentional injuries indicates a need to prioritise innovative measures for the primary prevention of adolescent injury. Funding: Bill & Melinda Gates Foundation

Mapping geographical inequalities in access to drinking water and sanitation facilities in low-income and middle-income countries, 2000-17

Background: Universal access to safe drinking water and sanitation facilities is an essential human right, recognised in the Sustainable Development Goals as crucial for preventing disease and improving human wellbeing. Comprehensive, high-resolution estimates are important to inform progress towards achieving this goal. We aimed to produce high-resolution geospatial estimates of access to drinking water and sanitation facilities. Methods: We used a Bayesian geostatistical model and data from 600 sources across more than 88 low-income and middle-income countries (LMICs) to estimate access to drinking water and sanitation facilities on continuous continent-wide surfaces from 2000 to 2017, and aggregated results to policy-relevant administrative units. We estimated mutually exclusive and collectively exhaustive subcategories of facilities for drinking water (piped water on or off premises, other improved facilities, unimproved, and surface water) and sanitation facilities (septic or sewer sanitation, other improved, unimproved, and open defecation) with use of ordinal regression. We also estimated the number of diarrhoeal deaths in children younger than 5 years attributed to unsafe facilities and estimated deaths that were averted by increased access to safe facilities in 2017, and analysed geographical inequality in access within LMICs. Findings: Across LMICs, access to both piped water and improved water overall increased between 2000 and 2017, with progress varying spatially. For piped water, the safest water facility type, access increased from 40·0% (95% uncertainty interval [UI] 39·4–40·7) to 50·3% (50·0–50·5), but was lowest in sub-Saharan Africa, where access to piped water was mostly concentrated in urban centres. Access to both sewer or septic sanitation and improved sanitation overall also increased across all LMICs during the study period. For sewer or septic sanitation, access was 46·3% (95% UI 46·1–46·5) in 2017, compared with 28·7% (28·5–29·0) in 2000. Although some units improved access to the safest drinking water or sanitation facilities since 2000, a large absolute number of people continued to not have access in several units with high access to such facilities (>80%) in 2017. More than 253 000 people did not have access to sewer or septic sanitation facilities in the city of Harare, Zimbabwe, despite 88·6% (95% UI 87·2–89·7) access overall. Many units were able to transition from the least safe facilities in 2000 to safe facilities by 2017; for units in which populations primarily practised open defecation in 2000, 686 (95% UI 664–711) of the 1830 (1797–1863) units transitioned to the use of improved sanitation. Geographical disparities in access to improved water across units decreased in 76·1% (95% UI 71·6–80·7) of countries from 2000 to 2017, and in 53·9% (50·6–59·6) of countries for access to improved sanitation, but remained evident subnationally in most countries in 2017. Interpretation: Our estimates, combined with geospatial trends in diarrhoeal burden, identify where efforts to increase access to safe drinking water and sanitation facilities are most needed. By highlighting areas with successful approaches or in need of targeted interventions, our estimates can enable precision public health to effectively progress towards universal access to safe water and sanitation