127 research outputs found

    Investigation of bio-aerosol dispersion in a tunnel-ventilated poultry house

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    Bio-aerosol concentrations in poultry houses must be controlled to provide adequate air quality for both birds and workers. High concentrations of airborne bio-aerosols would affect the environmental sustainability of the production and create environmental hazards to the surroundings via the ventilation systems. Previous studies demonstrate that several factors including the age of the birds, the housing configuration, the humidity and temperature would strongly affect the indoor concentration of bio-aerosols. However, limited studies are performed in the literature to investigate the bio-aerosol dispersion pattern inside poultry buildings. In order to fill a gap of the understanding of the bio-aerosol dispersion behavior, experimental measurements of the indoor bio-aerosol distribution are performed in a tunnel-ventilated poultry house in this paper. Meanwhile a three-dimensional computational fluid dynamics (CFD) model is built and validated to further investigate the effect of flow pattern, turbulence and vortex on the dispersion and deposition of the bio-aerosols. Furthermore, bio-aerosols with various diameters are also examined in the CFD model. It is found that higher concentrations of bio-aerosols are detected at the rear part of the house and strong turbulent flow resulting from the ventilation inlets enhances the diffusion and dispersion of bio-aerosols. Local vortex or disturbed flow is responsible for higher local concentration due to the re-suspension of settled bio-aerosols, which suggests that careful attentions should be paid to these locations during cleaning and disinfection. Results from present study contribute to the optimization of design and operation of the poultry houses from the standing point of reducing airborne bio-aerosol concentrations

    Investigation into an alternative approach of environmental control to enhance sensible heat transfer from broiler chickens during hot weather periods

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    Climatic conditions within the broiler building play an important role in the performances, health and welfare of broiler chickens. During hot weather periods, farmers in the temperate climates usually open all inlets onthe sidewall andoperate all the fans in theroof of thebroiler building to allow maximum airflow to relieve broilers of heat stress. However, the effects of this practice on the air velocity distribution in the broiler occupied zones of such type of building are not well documented. Therefore, this research work was set up to (1) investigate the impact of wide opened inlet on the airflow characteristics in the broiler occupied zones of an experimental broiler building at Harper Adams University, UK; (2) develop and evaluate the performance of a hot weather ventilation system, incorporatingan oscillation baffle, for broiler buildings; (3) examine the impact of the ventilation system on the airflow characteristics in the broiler occupied zones and the sensible heat transfer from broiler model. The results of the study indicated that the act of fully opening the inlets of broiler building during hot weather seasons did not improve the airflow in the broiler occupied zones at all measurement locations, including the sidewall area of the building. However, with the development of the hot weatherventilation system with oscillation baffle, operating at different fanfrequencies, baffle oscillation angles and baffle oscillation frequencies, there was a significant improvement in the average air velocity in the broiler occupied zones. At higher inlet turbulence, there was an increase in the sensible heat transfer from broilersin the sidewall area of the broiler building. This indicates that oscillation of inlet baffle instead of keeping it wide opened during the hot weather periods could direct moreairflow into the broiler occupied zones and relieve broiler chickens of heat stress

    Simulation of site-specific irrigation control strategies with sparse input data

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    Crop and irrigation water use efficiencies may be improved by managing irrigation application timing and volumes using physical and agronomic principles. However, the crop water requirement may be spatially variable due to different soil properties and genetic variations in the crop across the field. Adaptive control strategies can be used to locally control water applications in response to in-field temporal and spatial variability with the aim of maximising both crop development and water use efficiency. A simulation framework ‘VARIwise’ has been created to aid the development, evaluation and management of spatially and temporally varied adaptive irrigation control strategies (McCarthy et al., 2010). VARIwise enables alternative control strategies to be simulated with different crop and environmental conditions and at a range of spatial resolutions. An iterative learning controller and model predictive controller have been implemented in VARIwise to improve the irrigation of cotton. The iterative learning control strategy involves using the soil moisture response to the previous irrigation volume to adjust the applied irrigation volume applied at the next irrigation event. For field implementation this controller has low data requirements as only soil moisture data is required after each irrigation event. In contrast, a model predictive controller has high data requirements as measured soil and plant data are required at a high spatial resolution in a field implementation. Model predictive control involves using a calibrated model to determine the irrigation application and/or timing which results in the highest predicted yield or water use efficiency. The implementation of these strategies is described and a case study is presented to demonstrate the operation of the strategies with various levels of data availability. It is concluded that in situations of sparse data, the iterative learning controller performs significantly better than a model predictive controller

    Air pollution and livestock production

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    The air in a livestock farming environment contains high concentrations of dust particles and gaseous pollutants. The total inhalable dust can enter the nose and mouth during normal breathing and the thoracic dust can reach into the lungs. However, it is the respirable dust particles that can penetrate further into the gas-exchange region, making it the most hazardous dust component. Prolonged exposure to high concentrations of dust particles can lead to respiratory health issues for both livestock and farming staff. Ammonia, an example of a gaseous pollutant, is derived from the decomposition of nitrous compounds. Increased exposure to ammonia may also have an effect on the health of humans and livestock. There are a number of technologies available to ensure exposure to these pollutants is minimised. Through proactive means, (the optimal design and management of livestock buildings) air quality can be improved to reduce the likelihood of risks associated with sub-optimal air quality. Once air problems have taken hold, other reduction methods need to be applied utilising a more reactive approach. A key requirement for the control of concentration and exposure of airborne pollutants to an acceptable level is to be able to conduct real-time measurements of these pollutants. This paper provides a review of airborne pollution including methods to both measure and control the concentration of pollutants in livestock buildings

    Housing Environment and Farm Animals' Well-Being

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    This reprint contains articles from the Special Issue of Animals “Housing Environment and Farm Animals' Well-Being”, including original research, review, and communication related to livestock and poultry environmental management, air quality control, emissions mitigation, and assessment of animal health and well-being

    Control of particulate matter emissions from poultry and pig houses

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    Los alojamientos ganaderos, especialmente avícolas y porcinos, son una fuente importante de material particulado ("particulate matter", PM). Las concentraciones elevadas de PM en el ambiente pueden afectar a la salud de las personas y animales, así como al medio ambiente. La mejor manera de reducir las emisiones de PM de los alojamientos ganaderos es evitar que éste se genere y así, controlando el PM en origen, no sólo se pueden reducir las emisiones, sino también mejorar la calidad del aire en el interior de los alojamientos ganaderos. Por otra parte, para evaluar la posible exposición al PM por un lado, y para desarrollar medidas para reducirlo, por otro, es necesario conocer la morfología y composición de las partículas. En consecuencia, el objetivo de esta tesis fue identificar y caracterizar el origen del PM en diferentes sistemas de alojamientos ganaderos y evaluar técnicas de reducción de dicho PM en relación con otros contaminantes. La tesis está compuesta por cuatro trabajos de investigación y una revisión previa, sobre el estado de la cuestión del PM en los sistemas de producción ganaderos, que establece el marco del trabajo experimental. En primer lugar, se muestrearon fuentes conocidas de PM en alojamientos ganaderos que fueron aerosolizadas experimentalmente en un generador de polvo de laboratorio para recoger muestras de PM fino y grueso. Estas muestras fueron analizadas posteriormente mediante: i) microscopía electrónica de barrido con un espectrómetro de rayos X para obtener una caracterización morfológica y química detallada de las fuentes; ii) mediante un contador óptico de partículas para obtener la distribución por tamaños de cada fuente. En segundo lugar, se investigaron las características más adecuadas de las partículas para distinguir entre las distintas fuentes en base a la caracterización de las mismas anteriormente obtenida y a las características morfológicas obtenidas con análisis digital de imagen. En su conjunto, se puede concluir de manera genérica que los resultados presentados en esta tesis contribuyen a proporcionar unas herramientas básicas que permitirán diseñar unas medidas de reducción de PM en origen mejores y más eficientes y, paralelamente, a predecir su funcionamiento.Cambra López, M. (2010). Control of particulate matter emissions from poultry and pig houses [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/8501Palanci

    SPATIAL TRANSFORMATION PATTERN DUE TO COMMERCIAL ACTIVITY IN KAMPONG HOUSE

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    ABSTRACT Kampung houses are houses in kampung area of the city. Kampung House oftenly transformed into others use as urban dynamics. One of the transfomation is related to the commercial activities addition by the house owner. It make house with full private space become into mixused house with more public spaces or completely changed into full public commercial building. This study investigate the spatial transformation pattern of the kampung houses due to their commercial activities addition. Site observations, interviews and questionnaires were performed to study the spatial transformation. This study found that in kampung houses, the spatial transformation pattern was depend on type of commercial activities and owner perceptions, and there are several steps of the spatial transformation related the commercial activity addition. Keywords: spatial transformation pattern; commercial activity; owner perception, kampung house; adaptabilit
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