CFD Simulation of turbulence promoters in a water treatment reactor

A new immobilized flat plate photocatalytic reactor for wastewater treatment has been proposed in this study to avoid subsequent catalyst removal from the treated water. The reactor consists of an inlet, reactive section where catalyst is coated and an outlet parts. In order to optimize the fluid mixing and reactor design, this study aims to investigate the influence of baffles and its arrangement on the flat plate reactor hydrodynamics using computational fluid dynamics (CFD) simulation. For simulation, an array of baffles acting as turbulence promoters is inserted in the reactive zone of the reactor. In this regard, results obtained from the simulation of a baffled- flat plate photoreactor hydrodynamics for different baffle positions, heights and intervals are presented utilizing RNG k-ε turbulence model. Under the conditions simulated, the qualitative flow features, such as the development and separation of boundary layers, vortex formation, the presence of high shear regions and recirculation zones, and the underlying mechanism are examined. The influence of various baffle sizes on the distribution of pollutant concentration is also highlighted. The results presented here indicate that the spanning of recirculation increases the degree of interfacial distortion with a larger interfacial area between fluids which results in substantial enhancement in fluid mixing. The simulation results suggest that the qualitative and quantitative properties of fluid dynamics in a baffled reactor can be obtained which provides valuable insight to fully understand the effect of baffles and its arrangements on the flow pattern, behaviour, and feature.

Wavelet based spectral finite element modelling and detection of de-lamination in composite beams

In this paper, a model for composite beam with embedded de-lamination is developed using the wavelet based spectral finite element (WSFE) method particularly for damage detection using wave propagation analysis. The simulated responses are used as surrogate experimental results for the inverse problem of detection of damage using wavelet filtering. The WSFE technique is very similar to the fast fourier transform (FFT) based spectral finite element (FSFE) except that it uses compactly supported Daubechies scaling function approximation in time. Unlike FSFE formulation with periodicity assumption, the wavelet-based method allows imposition of initial values and thus is free from wrap around problems. This helps in analysis of finite length undamped structures, where the FSFE method fails to simulate accurate response. First, numerical experiments are performed to study the effect of de-lamination on the wave propagation characteristics. The responses are simulated for different de-lamination configurations for both broad-band and narrow-band excitations. Next, simulated responses are used for damage detection using wavelet analysis.

Aspectos teóricos del entrenamiento de padres en modificación de conducta.

El objetivo básico es obtener sistematización de resultados de diversos trabajos realizados sobre el tema del entrenamiento de padres respecto a la modificación de conducta. Estudiar y revisar la generalización, sobre todo la generalización temporal, de los cambios promovidos, éstos están estrechamente vinculados a la problemática de las técnicas empleadas en la evaluación de los mismos. Programas de entrenamiento de padres en modificación de conducta. Tratamiento comportamental infantil desde modelos mediados. Generalización de los cambios promovidos por el tratamiento comportamental. Se estudian resultados de diversos trabajos sobre el tema, proceso terapéutico complejo y multidimensional, estructurados en tres parámetros: tipos de programas; características de los padres o sujetos entrenados: rango de problemas infantiles abordados. Diversos modelos teóricos de intervención psicológica: modelos triádico (unidireccional); modelos triangular (interaccional); modelos integrales (en algunos interviene también el maestro). Parámetros con las siguientes facetas: programas de entrenamiento: contenido, métodos de implementación. Características de los padres: status socioecónomico; nivel intelectual; efectos de ciertos patrones conductuales. Rango de problemas infantiles: problemas de conducta; personalidad; lenguaje; alteraciones de conducta asociadas a síndromes complejos; trastornos de actividades psicofisiológicas. La aplicación de técnicas bibliométricas permite una aproximación, comprensiva y rigurosa al tema, así como a sus tendendias y desarrollos. El entrenamiento de padres responde a una concepción de intervención terapéutica infantil mediada. Debido al carácter multidimensional del proceso terapéutico se sistematizan los resultados relevantes en función de parámetros para presentar el panorama que hoy ofrece el tema en sus diversas facetas. La generalización de efectos es sobre todo aplicable al mantenimiento de los cambios promovidos y al transfer situacional y, en menor grado a la generalización de respuesta entre hermanos. La eficacia del entrenamiento de padres está por establecer. El entrenamiento de padres en modificación de conducta resulta recomendable como modelo económico y útil para abordar la problemática infantil donde se produce y mantiene. Se afirma la eficacia de la vía terapéutica mediada para lograr los objetivos de modificación conductual parental y los cambios programados en el comportamiento infantil. La eficacia del entrenamiento de padres en modificación de conducta alcanza distintos niveles en función de los problemas infantiles abordados. Entre los temas que señala para estudiar en mayor profundidad destacan: contenidos de los programas; estudio y validación de los manuales; problemas infantiles de personalidad; generalización de respuesta; técnicas de evaluación de resultados.

Prediction of nutrient digestibility and energy concentrations in fresh grass using nutrient composition

Improved nutrient utilization efficiency is strongly related to enhanced economic performance and reduced environmental footprint of dairy farms. Pasture-based systems are widely used for dairy production in certain areas of the world, but prediction equations of fresh grass nutritive value (nutrient digestibility and energy concentrations) are limited. Equations to predict digestible energy (DE) and metabolizable energy (ME) used for grazing cattle have been either developed with cattle fed conserved forage and concentrate diets or sheep fed previously frozen grass, and the majority of them require measurements less commonly available to producers, such as nutrient digestibility. The aim of the present study was therefore to develop prediction equations more suitable to grazing cattle for nutrient digestibility and energy concentrations, which are routinely available at farm level by using grass nutrient contents as predictors. A study with 33 nonpregnant, nonlactating cows fed solely fresh-cut grass at maintenance energy level for 50 wk was carried out over 3 consecutive grazing seasons. Freshly harvested grass of 3 cuts (primary growth and first and second regrowth), 9 fertilizer input levels, and contrasting stage of maturity (3 to 9 wk after harvest) was used, thus ensuring a wide representation of nutritional quality. As a result, a large variation existed in digestibility of dry matter (0.642-0.900) and digestible organic matter in dry matter (0.636-0.851) and in concentrations of DE (11.8-16.7 MJ/kg of dry matter) and ME (9.0-14.1 MJ/kg of dry matter). Nutrient digestibilities and DE and ME concentrations were negatively related to grass neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents but positively related to nitrogen (N), gross energy, and ether extract (EE) contents. For each predicted variable (nutrient digestibilities or energy concentrations), different combinations of predictors (grass chemical composition) were found to be significant and increase the explained variation. For example, relatively higher R(2) values were found for prediction of N digestibility using N and EE as predictors; gross-energy digestibility using EE, NDF, ADF, and ash; NDF, ADF, and organic matter digestibilities using N, water-soluble carbohydrates, EE, and NDF; digestible organic matter in dry matter using water-soluble carbohydrates, EE, NDF, and ADF; DE concentration using gross energy, EE, NDF, ADF, and ash; and ME concentration using N, EE, ADF, and ash. Equations presented may allow a relatively quick and easy prediction of grass quality and, hence, better grazing utilization on commercial and research farms, where nutrient composition falls within the range assessed in the current study.

Inhibition of Autonomic Storm by Epidural Anesthesia Does Not Influence Cardiac Inflammatory Response After Brain Death in Rats

Background. After brain death (BD) donors usually experience cardiac dysfunction, which is responsible for a considerable number of unused organs. Causes of this cardiac dysfunction are not fully understood. Some authors argue that autonomic storm with severe hemodynamic instability leads to inflammatory activation and myocardial dysfunction. Objectives. To investigate the hypothesis that thoracic epidural anesthesia blocks autonomic storm and improves graft condition by reducing the inflammatory response. Methods. Twenty-eight male Wistar rats (250-350 g) allocated to four groups received saline or bupivacaine via an epidural catheter at various times in relation to brain-death induction. Brain death was induced by a sudden increase in intracranial pressure by rapid inflation of a ballon catheter in the extradural space. Blood gases, electrolytes, and lactate analyses were performed at time zero, and 3 and 6 hours. Blood leukocytes were counted at 0 and 6 hours. After 6 hours of BD, we performed euthanasia to measure vascular adhesion molecule (VCAM)-1, intracellular adhesion molecule (ICAM)-1, interleukin (IL)-1 beta, tumor necrosis factor (TNF)-alpha, Bcl-2 and caspase-3 on cardiac tissue. Results. Thoracic epidural anesthesia was effective to block the autonomic storm with a significant difference in mean arterial pressure between the untreated (saline) and the bupivacaine group before BD (P < .05). However, no significant difference was observed for the expressions of VCAM-1, ICAM-1, TNF-alpha, IL-1 beta, Bcl-2, and caspase-3 (P > .05). Conclusion. Autonomic storm did not seem to be responsible for the inflammatory changes associated with BD; thoracic epidural anesthesia did not modify the expression of inflammatory mediators although it effectively blocked the autonomic storm.