Topic of this thesis is comparsion of emission concetration of solid pollutants in intensive poultry farming with different technologies. Measurement was done in cage system and two alternative poultry housing systems in company International poultry testing based in Ústrašice. For measurement of dust particles was used measurement device DUSTTRAK II 8530, own measurement has been done continuously for 24 hours with record every 3s. Dustiness was tracked in size fraction PM10. This dust particles can negatively influence health of employees and reared poultry. By measuring and following evaluation was found, that lowest value of dust particles was achieved in cage housing system. Considering health protection of employees and requirements for poultry wellfare is necessary keep dustiness of stable enviroment on lowest level.

徐慧敏. / 論文(碩士) -- 香港中文大學硏究院地理學部, 1997. / 參考文獻: leaves 156-166. / Xu Huimin. / 撮要 --- p.i / 鳴謝 --- p.ii / 目錄 --- p.iii / 表目錄 --- p.ix / 圖目錄 --- p.xii / Chapter 第一章 --- 導論 --- p.1 / Chapter 1.1 --- 引言 --- p.1 / Chapter 1.2 --- 研究目的 --- p.2 / Chapter 1.3 --- 硏究背景 --- p.2 / Chapter 1.4 --- 塵埃的來源 --- p.6 / Chapter 1.5 --- 塵埃與氣象因子 --- p.6 / Chapter 1.6 --- 塵埃的物理及化學成份 --- p.7 / Chapter 1.7 --- 選點 --- p.8 / Chapter 1.8 --- 論文結構 --- p.11 / Chapter 第二章 --- 硏究方法 --- p.12 / Chapter 2.1 --- 引言 --- p.12 / Chapter 2.2 --- 硏究地區 --- p.12 / Chapter 2.3 --- 硏究策略 --- p.15 / Chapter 2.4 --- 監測對象 --- p.15 / Chapter 2.4.1 --- 總懸浮粒子含量 --- p.15 / Chapter 2.4.2 --- 可吸入懸浮粒子含量 --- p.16 / Chapter 2.4.3 --- 顆粒大小及化學成份 --- p.16 / Chapter 2.5 --- 監測點佈局 --- p.18 / Chapter 2.5.1 --- 總懸浮粒子含量 --- p.18 / Chapter 2.5.2 --- 可吸入懸浮粒子含量 --- p.19 / Chapter 2.5.3 --- 塵埃顆粒大小 --- p.20 / Chapter 2.6 --- 監測時間 --- p.20 / Chapter 2.7 --- 監測技巧 --- p.21 / Chapter 2.7.1 --- 總懸浮粒子含量(TSP) --- p.22 / Chapter 2.7.2 --- 可吸入懸浮粒子含量（RSP) --- p.24 / Chapter 2.7.3 --- 塵埃的物理及化學特性 --- p.26 / Chapter a) --- 塵埃顆粒大小 --- p.26 / Chapter b) --- 塵埃化學成份 --- p.27 / Chapter 2.7.4 --- 氣象的資料 --- p.28 / Chapter 2.8 --- 數據處理 --- p.29 / Chapter 2.8.1 --- 富集因子 --- p.29 / Chapter 2.8.2 --- 因子分析 --- p.30 / Chapter 2.8.3 --- 空間的差異 --- p.30 / Chapter 2.8.4 --- 時間上的差異 --- p.31 / Chapter 2.8.5 --- 主要成份分析 --- p.31 / Chapter 2.8.6 --- 塵埃與天氣因子的關係 --- p.32 / Chapter 第三章 --- 塵埃在空間上的分佈及差異 --- p.33 / Chapter 3.1 --- 引言 --- p.33 / Chapter 3.2 --- 過往硏究 --- p.33 / Chapter 3.3 --- 總懸浮粒子含量（TSP) --- p.35 / Chapter 3.3.1 --- 監測點的污染程度 --- p.35 / Chapter 3.3.2 --- 總懸浮粒子含量在空間上的分佈情況 --- p.36 / Chapter 3.3.3 --- 塵埃的高峰水平的空間差異 --- p.38 / Chapter 3.3.4 --- 塵埃的低水平的空間差異 --- p.39 / Chapter 3.3.5 --- 監測點之間總懸浮粒子含量的相關系數 --- p.40 / Chapter 3.4 --- 可吸入懸浮粒子含量在空間上的分佈及差異 --- p.44 / Chapter 3.5 --- 中文大學的塵埃量與其他香港地方之比較 --- p.46 / Chapter 3.6 --- 討論 --- p.46 / Chapter 3.6.1 --- 與污染源…公路的距離 --- p.48 / Chapter 3.6.2 --- 盛行風向的影響 --- p.49 / Chapter 3.7 --- 小結 --- p.51 / Chapter 第四章 --- 塵埃在時間上的變化及差異 --- p.52 / Chapter 4.1 --- 引言 --- p.52 / Chapter 4.2 --- 過往硏究 --- p.52 / Chapter 4.3 --- 硏究結果 --- p.55 / Chapter 4.3.1 --- 總懸浮粒子含量(TSP) --- p.55 / Chapter 4.3.1.1 --- 季節的汚染程度 --- p.55 / Chapter 4.3.1.2 --- 總懸浮粒子在季節上含量分佈的情況 --- p.56 / Chapter 4.3.1.3 --- 塵埃的高峰水平季節差異(Peak dust level) --- p.58 / Chapter 4.3.1.4 --- 塵埃的低水平的季節差異(Trough dust level) --- p.60 / Chapter 4.3.1.5 --- 小結 --- p.62 / Chapter 4.3.2 --- 可吸入懸浮粒子含量在時間上的差異 --- p.62 / Chapter 4.3.2.1 --- 可吸入懸浮粒子在季節上的差異 --- p.63 / Chapter 4.3.2.2 --- 可吸入懸浮粒子含量在晝夜間的變化 --- p.66 / Chapter a) --- 變化規律 --- p.66 / Chapter b) --- 變化規律在月份上的差異 --- p.68 / Chapter 4.3.2.3 --- 可吸入懸浮粒子最高百分之五濃度及最低 百分之五濃度 --- p.68 / Chapter 4.3.2.4 --- 小結 --- p.72 / Chapter 4.3.3 --- 中大的總懸浮粒子含量與市區各點比較 --- p.72 / Chapter 4.3.4 --- 中大的可吸入懸浮粒子含量與市區各點比較 --- p.72 / Chapter 4.4 --- 討論 --- p.74 / Chapter 4.4.1 --- 塵埃在季節上的差異 --- p.74 / Chapter 4.4.1.1 --- 小結 --- p.79 / Chapter 4.4.2 --- 可吸入懸浮粒子含量在晝夜間的變化 --- p.79 / Chapter a) --- 晝夜間的塵埃變化與人文活動的關係 --- p.79 / Chapter b) --- 晝夜間的塵埃變化與風速之關係 --- p.83 / Chapter c) --- 海、陸和風跟可吸入懸浮粒子晝夜間變化的關係 --- p.84 / Chapter 4.4.3 --- 總結 --- p.87 / Chapter 第五章 --- 塵埃的元素濃度及顆粒大小 / Chapter 5.1 --- 引言 --- p.88 / Chapter 5.2 --- 元素濃度 --- p.88 / Chapter 5.2.1 --- 過往硏究 --- p.88 / Chapter 5.2.1.1 --- 富集因子(Enrichment factor-EF) --- p.89 / Chapter 5.2.1.2 --- 因子分析(Factor Analysis) --- p.91 / Chapter 5.2.2 --- 結果 --- p.92 / Chapter 5.2.2.1 --- 塵埃中元素濃度分佈與地域及季節的差別 --- p.92 / Chapter a) --- 空間分佈及差異 --- p.92 / Chapter b) --- 元素濃度在季節上的差異 --- p.95 / Chapter c) --- 中文大學的元素濃度與香港市區的情況比較 --- p.100 / Chapter 5.2.2.2 --- 富集程度 --- p.100 / Chapter a) --- 各元素的富集情況 --- p.101 / Chapter b) --- 富集因子在季節上的變化 --- p.103 / Chapter c) --- 中文大學塵埃元素的富集程度與其他硏究的比較 --- p.103 / Chapter 5.2.2.3 --- 因子分析 --- p.105 / Chapter 5.2.3 --- 討論 --- p.106 / Chapter 5.2.3.1 --- 空間差異 --- p.106 / Chapter 5.2.3.2 --- 季節之變化 --- p.107 / Chapter 5.2.3.3 --- 中文大學塵埃元素之來源 --- p.110 / Chapter 5.2.4 --- 小結 --- p.111 / Chapter 5.3 --- 塵埃顆粒大小 --- p.111 / Chapter 5.3.1 --- 過往硏究 --- p.111 / Chapter a) --- 顆粒大小 --- p.111 / Chapter b) --- 來源 --- p.112 / Chapter c) --- 成份 --- p.112 / Chapter d) --- 影響 --- p.112 / Chapter 5.3.2 --- 結果及討論 --- p.114 / Chapter 5.3.2.1 --- 塵埃顆粒大小在各監測月份的分佈情況 --- p.114 / Chapter 5.3.2.2 --- 塵埃顆粒大小的晝夜變化（diurnal variation) --- p.117 / Chapter 5.3.3 --- 小結 --- p.122 / Chapter 第六章 --- 塵埃與天氣因素的關係 --- p.124 / Chapter 6.1 --- 引言 --- p.124 / Chapter 6.2 --- 過往硏究 --- p.124 / Chapter 6.3 --- 數據及處理方法 --- p.128 / Chapter 6.4 --- 結果及討論 --- p.129 / Chapter 6.4.1 --- 各天氣類型及其特色 --- p.129 / Chapter 6.4.2 --- 天氣類型與塵埃之關係 --- p.132 / Chapter a) --- 高塵埃的天氣類型 --- p.136 / Chapter b) --- 低塵埃量的天氣類型 --- p.138 / Chapter 6.4.3 --- 天氣因子與塵埃之關係 --- p.139 / Chapter 6.5 --- 總結 --- p.143 / Chapter 第七章 --- 總結 --- p.145 / Chapter 7.1 --- 引言 --- p.145 / Chapter 7.2 --- 主要硏究結果 --- p.145 / Chapter 7.2.1 --- 空間差異 --- p.145 / Chapter 7.2.2 --- 時間變化 --- p.146 / Chapter 7.2.3 --- 元素濃度 --- p.148 / Chapter 7.2.4 --- 顆粒大小 --- p.149 / Chapter 7.2.5 --- 天氣類型 --- p.150 / Chapter 7.3 --- 硏究結果的含義 --- p.151 / Chapter 7.4 --- 本硏究的限制 --- p.154 / Chapter 7.5 --- 展望 --- p.155 / 參考書目 --- p.156

Most of the early wind erosion research undertaken in Australia, concentrated on how wind erosion affects cultivated farm land. However, in the 1990's the focus of wind erosion research in Australia started to shift to include rangeland environments. Initially these rangeland experiments used experimental configurations that were developed for cultivated fields. This meant that in most cases a sampler was set up in the middle of a field and it was assumed that the data collected was representative of the field as a whole. It was also assumed that temporal changes in dust fluxes/concentration reflect overall changes in the land type erodibility and wind erosivity. However, recent experiments and field observations within the rangelands, of the Channel Country suggest that this assumption is not valid. These experiments and observations suggest that there are substantial spatial and temporal variations in erodibility within individual land types. Such variations complicate the interpretation of temporal and spatial erosion trends. In particular, this variability implies that it is difficult to compare sampler data between different wind erosion events. To begin quantifying and comparing sampler data between events within the rangeland environments, the Dust Source Interaction Simulation Model (DSism) was developed to simulate the effect that physical processes and spatial variations in erodibility have upon observed dust concentration pro- files. The modelling/simulation approach used is closely linked to experimental data via the extensive use of sensitivity testing. Another key feature of the DSism approach, is its flexibility in allowing different dust source areas to have particle emission characteristics. This combined sensitivity testing and simulation approach has provided new insights into the wind erosion processes. By using DSism, it has been possible to identify several key features of the wind erosion process within rangeland environments. The first observation is that spatial and temporal changes in erodibility produce distinct changes in both the vertical and crosswind dust concentration profiles. Further investigations, indicate that the dispersion processes in operation vary from event to event. In particular, the results presented here indicate that surface heating plays an important role in some wind erosion events. These results also suggest that even small variations in the vertical dust concentration profile can reflect temporal and spatial changes in processes and erodibility. Finally the simulation results show that the particle size distribution of a vertical dust concentration profile depends on (a) the processes in operation during a given event and (b) the spatial variation in the particle size emission characteristics of the various source areas. These findings have several important implications. In particular, they indicate that both the crosswind and vertical dust concentration profiles can be viewed as amalgamation of several distinct plumes from different dust source areas and that dust concentration profiles contain significant information about both the spatial distribution of sources and the processes in operation during any given event. Most field studies have used regression models to describe the variation in dust concentration with height. A problem with this approach is that it assumes that the variation in dust concentration with height, always has a given functional form (or shape) and that dust concentration always decreases with height. Field observations, indicate that this assumption is only valid for some events within rangeland environments and that dust concentration does not always decrease with height in these environments. In most cases, such variations from the regression fit have been assumed to be the result of experimental 'noise' (error) or spatial variations in erodibility. This thesis presents, modelling and field evidence, which suggests that such variations, are the result of a combination of spatial variations in erodibility and changes in thermal conditions.

Even minimal improvements in particle collection efficiency of electrostatic precipitators significantly reduce dust emission from fossil-fuelled power stations and reduce pollution. Yet current designs rely on the Deutsch collection theory, which was developed for tubular precipitators and has been applied to wire-plate precipitators on the assumption that the inter-electrode electric fields at the same discharge distance in both were similar. Differences in geometry and associated collector electric fields and current density non-uniformity have not been taken into account, although the collector electric field and current density of the wire-plate precipitator are not uniform. And observations show that precipitated dust patterns and the distribution of collector current density are interrelated. Investigations revealed a simple square law relationship between the collector electric field and the collector current density in the space charge dominated coronas. Applying this relationship to the Deutsch collection theory led to a current-density-based collection formula that takes into account the non-uniform collector current density distribution. The current-density-based collection formula is then used to assess the impact of collector current density on collection efficiency, the results closely following published measurements. Applying the current-density-based collection formula to estimate the dust accumulation shows that most of the dust accumulates at collector locations facing the corona wires. The effect of the non-uniform precipitated dust layer on collection performance is assessed using the distributed corona impedance - the ratio of the inter-electrode voltage and the non-uniform collector current. Re-distribution of the collector current profile as dust builds up is also compatible with published measurements. Finally this is applied to optimize the wire-plate precipitator collection performance. This shows that optimal collection performance is obtained with the wire-wire spacing less than the wire-plate distance, once again confirming published experimental results. This is the first analytical approach to show better collection performance can be achieved at the ratio of wire-wire spacing/wire-plate distance not equal to unity, which has been the standard industry practice since 1960.

Doctor of Philosophy(PhD) / Complex (dusty) plasmas are a subject of growing interest. They areionized gases containing charged dust particles. In capacitively-coupled RF discharges, dust growth can occur naturally and two methods can be used to grow dust particles: chemically active plasmas or sputtering. The growth of dust particles in argon discharges by RF sputtering and the effect of dust particles on theplasma have been investigated from the plasma ignition to the afterglow. It was shown that plasma and discharge parameters are greatly affected by the dust particles. Furthermore, plasma instabilities can be triggered by the presence of the dust particles. These instabilities can be due to dust particle growth or they can be instabilities of a well established dust cloud filling the interelectrode space. When the discharge is switched off, the dust particles act like a sink for the charge carrier and consequently affect the plasma losses. It was shown that the dust particles do keep residual chargeswhich values are greatly affected by the diffusion of the charge carriers and especially the transition from ambipolar to free diffusion.

Currently, a lack of accurate emission data exits for particulate matter (PM) in agricultural air quality studies (USDA-AAQTF, 2000). PM samplers, however, tend to over estimate the concentration of most agricultural dusts because of the interaction of the particle size distribution (PSD) and performance characteristics of the sampler (Buser, 2004). This research attempts to find a practical method to characterize and correct this error for the Federal Reference Method (FRM) PM10 sampler. First, a new dust wind tunnel testing facility that satisfies the USEPA’s requirement of testing PM10 samplers was designed, built, and evaluated. Second, the wind tunnel testing protocol using poly-dispersed aerosol as the test dust was proved to be able to provide results consistent with mono-dispersed dusts. Third, this study quantified the variation of over sampling ratios for the various cut point and slopes of FRM PM10 samplers and proposed an averaged over sampling ratio as a correction factor for various ranges of PSD. Finally, a method of using total suspended particle (TSP) samplers as a field reference for determining PM10 concentrations and aerosol PSD was explored computationally. Overall, this dissertation developed successfully the methodology to correct the sampling error associated with the FRM PM10 sampler: (1) wind tunnel testing facilities and protocol for experimental evaluation of samplers; (2) the variation of the oversampling ratios of FRM PM10 samplers for computational evaluation of samplers; (3) the evaluation of TSP sampler effectiveness as a potential field reference for field evaluation of samplers.

A dust layer, especially based on high-resistivity dust, at the collecting electrodes may cause a back corona discharge in electrostatic precipitators (ESP). It can significantly reduce the ESP efficiency and as a result cause ecological damages. To study the dust layer influence inside ESPs, it is necessary to derive an adequate model of the ESP precipitation process with a dust layer at the collecting electrode. The research of the present thesis is focused on stationary studies of the precipitation process with a dust layer at the collecting electrode in ESPs. Three mathematical models are proposed as a description of the precipitation process with a dust layer at the collecting electrode. The models are based on Maxwell’s equations and the finite element method (FEM). COMSOL Multiphysics software is used for their implementation. In all models the dust layer has constant conductivity and the air region has constant ion mobility. In the first model there are no coupling conditions, which is required in mathematics, are given between the two regions. The solution found by COMSOL Multiphysics does not provide physically acceptable coupling conditions. In the second model, a continuous transition zone is introduced between the two regions so that no coupling conditions are required. With the large derivatives in the transition zone, the nonlinear solver in COMSOL Multiphysics does not converge. Finally, in the third model, the dust layer and the grounded collecting electrode are replaced with a boundary condition for the air region. The properties of the third model are investigated, and these models can be used to study the influence of the dust layer. The results of these investigations are reported and discussed.

International standards establish criteria for size-selective aerosol sampling for industrial hygiene. Commercially available aerosol samplers are designed to conform to these criteria. This study uses semi-monodispersed aerosols generated in a vertically aligned test chamber to compare the performance of three commercially available respirable dust samplers, one of which can, in addition, simultaneously sample for thoracic and inhalable dust fractions. Comparison methods are used to calculate a theoretical fractional value based on the appropriate sampling conventions of the total dust concentration and size distribution of test materials. Performance of actual samplers can be conducted by comparing observed results to the theoretical value. Results show the design of the test chamber and use of fused aluminum oxide is appropriate to conduct simplified performance verification tests for inhalable and respirable dust samplers. This study showed the TSI RespiCon followed the inhalable and respirable conventions closely, but results for the thoracic fraction required the use of a correction factor. The SKC aluminum cyclone tended to undersample the respirable fraction, while the BGI CAS4 cyclone and the TSI RespiCon appear to most closely follow the convention. Improved selection of test material and characterization of particle sizes are recommended to further develop this method of performance verification.

published_or_final_version / Medicine / Master / Doctor of Medicine

All classes of Active Galactic Nuclei (AGN) are fundamentally powered by accretion of gas onto a supermassive black hole. The process converts the potential energy of the infalling matter to X-ray and ultraviolet (UV) radiation, releasing up to several 1012 solar luminosities. Observations show that the accreting "central engines" in AGN are surrounded by dusty matter. The dust occupies a "torus" around the AGN which is comprised of discrete clumps. If the AGN radiation is propagating through the torus on its way to an observer, it will be heavily re-processed by the dust, i.e. converted from UV to infrared (IR) wavelengths. Much of the information about the input radiation is lost in this conversion process while an imprint of the dusty torus is left in the released IR photons. Our group was the first to formulate a consistent treatment of radiative transfer in a clumpy medium an important improvement over simpler models with smooth dust distributions previously used by researchers. Our code CLUMPY computes spectral energy distributions (SED) for any set of model parameters values. Fitting these models to observed AGN SEDs allows us to determine important quantities, such as the torus size, the spatial distribution of clumps, the torus covering factor, or the intrinsic AGN luminosity. Detailed modeling also permits us to study the complex behavior of certain spectral features. IR radiative transfer introduces degeneracies to the solution space: different parameter values can yield similar SEDs. The geometry of the torus further exacerbates the problem. Knowing the amount of parameter degeneracy present in our models is important for quantifying the confidence in data fits. When matching the models to observed SEDs we must employ modern statistical methods. In my research I use Bayesian statistics to determine the likely ranges of parameter values. I have developed all tools required for fitting observed SEDs with our large model database: the latest implementation of CLUMPY, the fit algorithms, the Markov Chain Monte Carlo sampler, and the Bayesian estimator. In collaboration with observing groups we have applied our methods to a multitude of real-life AGN.