Analytical modeling of DSG in parabolic trough solar collectors

Direct steam generation (DSG) in the absorber pipes of parabolic trough solar collectors is a promising procedure since the thermal fluid is water instead of thermal oil, as conventional solar concentrating systems use. It enables higher cycle temperatures and efficiencies, reducing the cost of the system. This paper presents an analytical model of (DSG) process in parabolic trough collectors. A collector row was divided in three sections and for each section a system of differential equations was derived. The model was implemented and simulations performed using a configuration and parameters similar to works published in the technical literature. Results of simulation have shown good agreement with them and allow obtaining many important parameters of the (DSG) process along the collector row: external and internal absorber temperature, fluid flow and temperature, vapor title and useful energy. A linear relationship between useful energy and collected irradiance has been obtained. Using the utilizability method, this result enables to make long term predictions about the system’s performance.Generación directa de vapor (GDV) en los tubos absorbedores de colectores solares cilindro parabólicos es un procedimiento promisorio ya que utiliza agua como fluido térmico en lugar de aceite (utilizado en los procedimientos convencionales). Permite temperaturas y por tanto eficiencias más elevadas del ciclo Rankine, reduciendo el costo del sistema. Este trabajo presenta un modelo analítico del proceso GDV en colectores solares cilindro-parabólicos. La columna de colectores fue dividida en tres secciones y se obtuvo un sistema de ecuaciones diferenciales para cada una de ellas. El modelo fue implementado y las simulaciones se realizaron con una configuración y parámetros similares a los trabajos publicados en la literatura técnica. Los resultados muestran un buen acuerdo con ellos y permiten la obtención de muchos parámetros importantes del proceso GDV a lo largo de la columna de colectores: temperatura interna y externa del tubo absorbedor, caudal y temperatura del fluido térmico, título de vapor y energía útil. Se ha obtenido una relación lineal entre la energía útil y la irradiación solar colectada. Por medio del método de utilizabilidad, este resultado permite hacer predicciones a largo plazo sobre el rendimiento del sistema.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Analytical modeling of DSG in parabolic trough solar collectors

Direct steam generation (DSG) in the absorber pipes of parabolic trough solar collectors is a promising procedure since the thermal fluid is water instead of thermal oil, as conventional solar concentrating systems use. It enables higher cycle temperatures and efficiencies, reducing the cost of the system. This paper presents an analytical model of (DSG) process in parabolic trough collectors. A collector row was divided in three sections and for each section a system of differential equations was derived. The model was implemented and simulations performed using a configuration and parameters similar to works published in the technical literature. Results of simulation have shown good agreement with them and allow obtaining many important parameters of the (DSG) process along the collector row: external and internal absorber temperature, fluid flow and temperature, vapor title and useful energy. A linear relationship between useful energy and collected irradiance has been obtained. Using the utilizability method, this result enables to make long term predictions about the system’s performance.Generación directa de vapor (GDV) en los tubos absorbedores de colectores solares cilindro parabólicos es un procedimiento promisorio ya que utiliza agua como fluido térmico en lugar de aceite (utilizado en los procedimientos convencionales). Permite temperaturas y por tanto eficiencias más elevadas del ciclo Rankine, reduciendo el costo del sistema. Este trabajo presenta un modelo analítico del proceso GDV en colectores solares cilindro-parabólicos. La columna de colectores fue dividida en tres secciones y se obtuvo un sistema de ecuaciones diferenciales para cada una de ellas. El modelo fue implementado y las simulaciones se realizaron con una configuración y parámetros similares a los trabajos publicados en la literatura técnica. Los resultados muestran un buen acuerdo con ellos y permiten la obtención de muchos parámetros importantes del proceso GDV a lo largo de la columna de colectores: temperatura interna y externa del tubo absorbedor, caudal y temperatura del fluido térmico, título de vapor y energía útil. Se ha obtenido una relación lineal entre la energía útil y la irradiación solar colectada. Por medio del método de utilizabilidad, este resultado permite hacer predicciones a largo plazo sobre el rendimiento del sistema.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Analysis of spinel based inclusions during the last stage of the steelmaking process of SAE 52100

Al2 O3 (alumina) and MgO·Al2 O3 (spinel) inclusions cause valve obstruction (clogging) in continuous casting and can deteriorate the quality of the final product. In this context, industrial heats of the bearing steel SAE 52100 was examined. Samples were collected in the final steps of the steelmaking process, both after vacuum treatment and during continuous casting. A scanning electron microscope (SEM) equipped with a energy-dispersive spectrometer (EDS) and automated particle characterization analysis was used to characterize the inclusions present in the steel samples. Thermodynamic calculations were performed with the commercial software FactSageTM 7.2. Based on thermodynamic predictions, parameters such as solid fraction, liquid fraction, MgO saturation point of the slags, content of dissolved elements in steel (Al, Mg, Ca,...) and the construction of a phase stability diagram were determined. The results in this study showed a tendency for increase in MgO content in the inclusions with the decrease of %FeO and SiO2 contents in the slag, an increase of binary basicity (%CaO/%SiO2 ). It is verified that the MgO contents in the slag were close to the saturation, increasing the probability for the formation of inclusions rich in MgO and/or spinel. On the other hand, stability diagrams confirm the formation of spinel inclusions for each of the heats analyzed. During the final step of the steelmaking process, there is a tendency for re-oxidation, which is verified by an increase in the density of inclusions (or total oxygen TO values)

CLARIPED: a new tool for risk classification in pediatric emergencies

AbstractObjectiveTo present a new pediatric risk classification tool, CLARIPED, and describe its development steps.MethodsDevelopment steps: (i) first round of discussion among experts, first prototype; (ii) pre-test of reliability, 36 hypothetical cases; (iii) second round of discussion to perform adjustments; (iv) team training; (v) pre-test with patients in real time; (vi) third round of discussion to perform new adjustments; (vii) final pre-test of validity (20% of medical treatments in five days).ResultsCLARIPED features five urgency categories: Red (Emergency), Orange (very urgent), Yellow (urgent), Green (little urgent) and Blue (not urgent). The first classification step includes the measurement of four vital signs (VIPE score); the second step consists in the urgency discrimination assessment. Each step results in assigning a color, selecting the most urgent one for the final classification. Each color corresponds to a maximum waiting time for medical care and referral to the most appropriate physical area for the patient's clinical condition. The interobserver agreement was substantial (kappa=0.79) and the final pre-test, with 82 medical treatments, showed good correlation between the proportion of patients in each urgency category and the number of used resources (p<0.001).ConclusionsCLARIPED is an objective and easy-to-use tool for simple risk classification, of which pre-tests suggest good reliability and validity. Larger-scale studies on its validity and reliability in different health contexts are ongoing and can contribute to the implementation of a nationwide pediatric risk classification system

CLARIPED: um novo instrumento para classificação de risco em emergências pediátricas

ResumoObjetivoApresentar um novo instrumento de classificação de risco pediátrico, o CLARIPED, e descrever as etapas de seu desenvolvimento.MétodosEtapas do desenvolvimento: (i) primeira rodada de discussão entre especialistas, primeiro protótipo; (ii) pré‐teste de confiabilidade, 36 casos hipotéticos; (iii) segunda rodada de discussão para ajustes; (iv) treinamento da equipe; (v) pré‐teste com pacientes em tempo real; (vi) terceira rodada de discussão para novos ajustes; (vii) pré‐teste final de validade (20% dos atendimentos de cinco dias).ResultadosO CLARIPED apresenta cinco categorias de urgência: Vermelha (emergência), Laranja (muito urgente), Amarela (urgente), Verde (pouco urgente) e Azul (sem urgência). A primeira etapa da classificação inclui a aferição de quatro sinais vitais (escore Vipe); a segunda etapa consiste na avaliação de discriminadores de urgência. Cada etapa resulta na atribuição de uma cor, seleciona‐se a de maior urgência para a classificação final. Cada cor corresponde a um tempo máximo de espera pelo atendimento médico e ao encaminhamento à área física mais adequada à condição clínica do paciente. A concordância interobservador foi substancial (kappa=0,79) e o pré‐teste final, com 82 atendimentos, evidenciou boa correlação entre a proporção de pacientes em cada categoria de urgência e o número de recursos usados (p<0,001).ConclusõesO CLARIPED é um instrumento para classificação de risco simples, objetivo e de fácil uso, cujos pré‐testes sugerem boa confiabilidade e validade. Estudos em maior escala sobre sua validade e confiabilidade em diferentes contextos de saúde estão em curso e podem contribuir para a adoção de um sistema de classificação de risco pediátrico em âmbito nacional.AbstractObjectiveTo present a new pediatric risk classification tool, CLARIPED, and describe its development steps.MethodsDevelopment steps: (i) first round of discussion among experts, first prototype; (ii) pre‐test of reliability, 36 hypothetical cases; (iii) second round of discussion to perform adjustments; (iv) team training; (v) pre‐test with patients in real time; (vi) third round of discussion to perform new adjustments; (vii) final pre‐test of validity (20% of medical treatments in five days).ResultsCLARIPED features five urgency categories: Red (Emergency), Orange (very urgent), Yellow (urgent), Green (little urgent) and Blue (not urgent). The first classification step includes the measurement of four vital signs (Vipe score); the second step consists in the urgency discrimination assessment. Each step results in assigning a color, selecting the most urgent one for the final classification. Each color corresponds to a maximum waiting time for medical care and referral to the most appropriate physical area for the patient's clinical condition. The interobserver agreement was substantial (kappa=0.79) and the final pre‐test, with 82 medical treatments, showed good correlation between the proportion of patients in each urgency category and the number of used resources (p<0.001).ConclusionsCLARIPED is an objective and easy‐to‐use tool for simple risk classification, of which pre‐tests suggest good reliability and validity. Larger‐scale studies on its validity and reliability in different health contexts are ongoing and can contribute to the implementation of a nationwide pediatric risk classification system

NITROGEN FERTILIZATION IN CORN WITH DIFFERENT SOURCES OF NITROGEN

O nitrogênio é um dos nutrientes mais necessários em maior quantidade pela cultura do milho, o sistema de cobertura que o antecede deve ser pensado de forma a evitar perdas, além de possuir a capacidade de fornecer nitrogênio externo ao sistema. O objetivo deste trabalho é analisar qual fonte de N proporciona maior produtividade com a adubação nitrogenada na cultura do milho em segunda safra, quanto as suas fontes e possibilidades para reduzir a perda do N. O experimento foi realizado na fazenda Santana, Vianópolis, GO. O delineamento experimental adotado foi o de blocos ao acaso, com quatro tratamentos e quatro repetições. Os tratamentos foram assim divididos: T1 – testemunha, sem utilização de adubação; T2 – 267 kg ha-1 de ureia granulada e 100 kg ha-1 de KCl; T3 – 267 kg ha-1 de ureia granulada protegida e 100 kg ha-1 de KCl; T4 – 445 kg ha-1 de nitrato de amônio e 100 kg ha-1 de KCl. Foram utilizados como parâmetros de avaliações a altura da planta, o diâmetro de colmo e a produtividade. Os resultados foram submetidos à análise de variância, e quando ocorreram diferenças significativas, identificadas pelo teste F (P&lt;0,05), se aplicou o teste de médias de Tukey. Não há efeito na produtividade do milho devido a proteção da ureia, desde que não ocorra restrições hídricas para a cultura do milho na safrinha. O nitrato de amônio não apresenta desempenho superior a ureia, desde que não ocorra restrição hídrica para o milho safrinha. A adubação nitrogenada é imprescindível para a produtividade do milho.Nitrogen is one of the nutrients most needed in greater quantity by the corn crop, the coverage system that precedes it must be designed in order to avoid losses, in addition to having the capacity to supply external nitrogen to the system. The objective of this work is to analyze which source of N provides greater productivity with nitrogen fertilization in corn in the second crop, regarding its sources and possibilities to reduce N loss. The experiment was carried out at Santana farm, Vianópolis, GO. The experimental design adopted was randomized blocks, with four treatments and four replications. The treatments were divided as follows: T1 – control, without the use of fertilizer; T2 – 267 kg ha-1 of granulated urea and 100 kg ha-1 of KCl; T3 – 267 kg ha-1 of protected granulated urea and 100 kg ha-1 of KCl; T4 – 445 kg ha-1 of ammonium nitrate and 100 kg ha-1 of KCl. Plant height, stem diameter and productivity were used as evaluation parameters. The results were submitted to analysis of variance, and when significant differences occurred, identified by the F test (P&lt;0.05), Tukey's test of means was applied. There is no effect on corn productivity due to the protection of urea, as long as there are no water restrictions for the corn crop in the off-season. Ammonium nitrate does not perform better than urea, as long as there is no water restriction for safrinha corn. Nitrogen fertilization is essential for corn productivity

Relationship between ultrasound measurement of quadriceps muscle and nutritional status in ICU patients in a high-complexity trauma care hospital

Introduction Muscle mass assessment of critically ill patients is essential to be part of the nutritional diagnosis in hospital care. Thus, the evaluation of more specific techniques for that purpose is needed. The present study aimed to investigate the association of quadriceps muscle thickness (QMT), measured by ultrasound (US), with the nutritional status of critically ill patients in a referral high-complexity trauma care hospital. Methods A cross-sectional observational study was conducted in the intensive care units (ICUs) in a tertiary hospital in Brazil. The sample comprised 30 critically ill trauma patients admitted between February and March 2022. The methodology involved evaluating muscle mass and comparing nutritional status through mid-upper arm circumference measurements and US assessments. Specifically, the QMT was quantified using US at a predefined site between the iliac crest and the proximal border of the patella. Results The Kruskal-Wallis test indicated variability in QMT between the nutritional status groups, with statistical significance reached after excluding the overweight group (H(2) = 7.532, p = 0.023). The moderate malnutrition group exhibited notably lower QMT. Sensitivity analyses using bootstrap and Monte Carlo methods showed moderate trends toward significance. A positive correlation was found between QMT and mid-upper arm circumference adequacy (p &lt; 0.05), demonstrating fair to moderate correlation (rs = 0.531). Conclusion Significant changes in QMT were detected by ultrasound assessment in moderate malnutrition patients compared to patients of other nutritional statuses. Ultrasound may be a valuable technique for monitoring muscle integrity in critically ill patients

Evaluation of the limitations in daily-life activities and quality of life in leprosy ­patients submitted to surgical neurolysis to treat neuritis

La neurólisis es indicada para reducir el sufrimiento neural e impedir la instalación de secuelas e incapacidades en pacientes con lepra. El objetivo de este estudio fue verificar el grado de limitación de las actividades de la vida diaria y la calidad de vida de pacientes con lepra sometidos a neurólisis para el tratamiento de las neuritas. Participaron del estudio los pacientes sometidos a neurólisis en el período de 1998 a 2011. Fueron recolectadas informaciones sociodemográficas y clínicas, limitaciones de las actividades (SALSA) y la calidad de vida (WHOQOL-bref). Los análisis estadísticos incluirán la frecuencia, las medidas de tendencia central y dispersión, los tests de Mann-Whitney, Kruskall-Wallis y los coeficientes de correlación de Spearman adoptando pNeurolysis is indicated to reduce neural suffering and to prevent sequelae and disabilities in leprosy patients. The aim of this study was to determine the ­degree of limitation of daily activities and quality of life in leprosy patients submitted to neurolysis for neuritis treatment. The study included patients who underwent neurolysis from 1998 to 2011. We collected demographic and clinical information, data about activity limitations (Screening of Activity Limitation and Safety Awareness [SALSA]) and quality of life (WHO Quality of Life - Short Form-26 [WHOQOL-BREF]). Statistical analyses included frequency, central tendency and dispersion measures, Mann-Whitney and Kruskal-Wallis' tests, and Spearman's correlation coefficient adopting pA neurólise é indicada para reduzir o ­sofrimento neural e impedir a instalação de sequelas e incapacidades em pacientes com hanseníase. O objetivo deste estudo foi verificar o grau de limitação das atividades e a qualidade de vida de pacientes com hanseníase submetidos a neurólise para tratamento das neurites. Participaram do estudo os pacientes submetidos à neurólise no período de 1998 a 2011. Foram coletadas informações sociodemográficas e clínicas, limitações das atividades (SALSA) e a qualidade de vida (WHOQOL-bref). As análises estatísticas incluíram a frequência, as medidas de tendência central e dispersão, os testes de Mann-Whitney e Kruskall-Wallis e o coeficiente de correlação de Spearman adotando-se