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Dust accumulation on photovoltaic (PV) modules and its effect on their performance are of high concern for regions with a high rate of dust, low frequency and intensity of rain. In this thesis, the effect of dust on PV modules is investigated with respect to dust concentration and spectral transmittance. The measured spectral transmittance of the dust sample shows spectral attenuation effect that varies at different wavelengths. This effect is explained by the particle size distribution of the dust samples: At shorter wavelengths more light is scattered due to the effect of the smaller particles. This effect has a major impact on the PV module as it affects PV technologies with a wider band-gap more than those of a narrower band-gap. The effect of dust is accumulative, i.e. PV module performance is reduced by increasing deposition over time or until it's cleared manually or by rain. The tilt angle of the PV installation plays a major role in the amount of dust accumulated on the devices, where higher tilt angles result in decreased dust concentrations. This effect is demonstrated in outdoor measurements where tilted modules had lower losses in daily as well as total array yield. It is also shown that tilted modules benefit from precipitation more than horizontal modules. However over the exposure period the modules did not show any clear aging effect caused specifically from dust accumulation or exhibit any seasonal variation. Different tilt angles can produce varying non-uniform dust patterns on the device surface. This effect and its pattern over long and short periods of exposure are investigated by means of spatial three dimensional modelling. The simulations compare two dust accumulation patterns that represent a short exposure to a single dusty day (one day) and a long exposure of dust (3 months). Out of the two patterns, the long exposure patterns showed higher losses of 19.4% in comparison to 14.8% for the short exposure. The simulation also showed that dust accumulation that promotes high concentration of dust at the bottom of the PV modules where it covers a full cell has a high risk of triggering hot spots and thus risks permanent module damage. A dust correction model for energy prediction is developed. The model takes into consideration dust concentration, spectral attenuation effect of dust, PV technology, and various meteorological variables. The modified spectral transmittances of the dust were incorporated into the model in the form of pre-measured data. This means in this work samples collected in Kuwait were measured and used to generate the input. The model is compared against the outdoor measured data and a good agreement between measurements iv and simulations is demonstrated. Using this model two procedures were developed. The first evaluates the uncertainties associated with dust over long periods of time. The second is to find the optimised cleaning schedule and frequency of cleaning based on acceptable yield loss margins over the simulated period of time. The optimisation of the cleaning schedule showed that for Kuwait setting the daily energy losses in PV modules at less than 10% will set the cost of cleaning higher than the cost of energy lost due to dust.

The total luminosity of the Rho Ophiuchi molecular cloud is derived from IRAS data and is found to match the luminosity of known embedded sources very closely. High resolution 60 and 100 micron band IRAS images have been reduced to yield equilibrium color temperature maps and 60 micron band dust optical depth maps for the region. These data along with optically thin C18O column density data are used to evaluate dust grain sizes and compositions via competing grain models. Radiative modeling shows that a standard power law distribution of graphite and silicate grains is responsible for IRAS 60 and 100 micron band emissions. These grains are heated to about one tenth of the cloud's depth in the core region. Their optical depths closely follow molecular column density structure, but these grains are considerably colder than the molecular gas. We also find that a 10 nm minimum particle radius cutoff is appropriate for the 60 and 100 micron band emissions while very small grains or PAH molecules dominate the cloud's 12 and 25 micron band emissions.

The main material of electric arc furnace steel makers is scrap steel. The scrap steel was melted and reduced into molten steel and the substance of lower melting and boiling points are concentrated in fly ash. The ash collected by dust collector contains also, other than organic pollutants like polycyclic aromatic hydrocarbons, (PAHs), inorganic heavy metal pollutants, such as zinc, cobalt and lead. It is found that the content of zinc and cobalt in the ash are exceeding statutory standard of 5 mg/L and 1 mg/L. They are hazardous industrial waste.In the Steel Basic Industry Collected Dust Storage Extending Review Operation Key Point as amended on July 1, 2010 by Environmental Protection Administration, all the steel mills shall complete treatment of the stored collected dust before June 30, 2014 and no further storage will be permitted. Due to the fact that domestic capacity of treating collected dust is insufficient to meet the statutory requirements, the final treatment and disposition of collect duct has become a serious question to the steel mills.In this research, we press the dust collected in the process of arc furnace steel making into ingot and place into arc furnace for further melting and refining. Under temperature of 1600 ¢Jpart of the heavy metal is gasified and returned to waste gas and become collected dust and part of Silicon Dioxide and Magnesium Oxide are sintered into slag and turn the hazardous industrial waste into recycled industrial waste for further utilization, so that they may be disposed. After melting treatment, the collected dust, the regenerated dust has the zinc compound content increased to 13.45% and therefore increases the recycling value of collected dust. In this process, Iron Oxide is reduced 9.41% which can be turned into steel billet (product) and Silicon Dioxide and Magnesium Oxide are reduced 2.67% and were turned into slag.Results of this research indicated that after melting treatment of collected dust, it will be reduced 0.26% and is therefore good for waste reduction.

Thesis (M.S.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains xii, 91 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 76-78).

Thèse--Nancy. / "Bibliographie": p. [239]-252.

Purpose Pneumoconiosis is a kind of diffuse lung fibrosis disease caused by long-term inhalation of industrial dust and retention in the lungs. In recent years, the incidence of pneumoconiosis decline in Europe, America and other developed countries, but remains stubbornly high in China, and even shows a rising trend. Currently, China does not have a comprehensive pneumoconiosis risk index system for risk assessment. This project aims to review methods to construct the risk index system of occupational dust exposure. A comprehensive, evidence-based and practical risk index system will offer a solid foundation for calculating the risk index weightings, adjusting indicator system and practical application in the future. Method Pubmed search was conducted for all the literature in 2000 -2014 about the risk factors of pneumoconiosis. RCT trials, cohort studies and case-control studies were identified to explore the risk factors of pneumoconiosis. Animal experiments, clinical research, radiological research, genetic research, and simple descriptive studies were excluded. Referring to "The Law of Occupational Disease Prevention in People's Republic of China" and national occupational health risk assessment system in other countries and an occupational dust risk index system prototype was formulated. Result 19 highly relevant literatures were identified from the systematic review. We found that dust concentration, working duration, age and smoking habit are highly correlated to the risk of pneumoconiosis. Combined with occupational health risk assessment systems in other countries and "The Law of Occupational Disease Prevention in People's Republic of China", the primary occupational risk index system was built. The system totally included four level indicators, 11 secondary indicators and 48 tertiary level indicators, covering human factors, physical factors, environmental factors and the management factors. Conclusion The primary risk index system not only covers the detail of production process from the dust generation to the dust spread, but also includes personal risk exposure caused by individual differences, working environment and hazards caused by improper management. It is trusted to be a comprehensive risk index. However, the index system needs further statistical analysis, like setting the index weight and testing with the data collecting from actual work, to improve the rationality and practicality of the index system. / published_or_final_version / Public health / Master / Master of Public Health

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This thesis encompasses the study of the mid-infrared (IR) dust properties in diffuse high latitude cirrus and in the dense environments of supernova remnants (SNRs) in the plane of our Galaxy. Unlike the well known emission properties of dust grains in the diffuse ISM in the far-IR and submillimeter, the mid-IR spectrum is still relatively unconstrained. We extend the correlation of dust emission with H I column densities to mid-IR wavelengths and look for evidence of variations in the emissivity of dust associated with local and halo gas. This is accomplished by spatially correlating the IR maps from the IRIS/IRAS survey at 12, 25, 60 and 100 μm with H I column density maps inferred from 21-cm line emission observations obtained with the GBT (at a 9′ resolution). We find that IVCs (halo clouds thought to be part of the Galactic fountain) show color ratios consistent with a dust evolution scenario in which large dust grains are shattered into smaller ones (VSGs). The low 12 μm emission found suggests a reduced abundance of PAHs in IVCs. We also address the IR extragalactic emission seen in our residual maps and quantify its power spectrum behaviour. Continuing with the mid-IR theme, we conducted a comprehensive study of the morphology and energetics of SNRs in the plane of our Galaxy. We make use of the Spitzer MIPSGAL (at 24 and 70 μm) and GLIMPSE (at 8 μm) surveys to detected infrared counterparts to SNR candidates in Green’s catalog. We find that a third of the sample shows IR emission and calculate the corresponding fluxes. We explore the relation between IR colors to place constraints on the different IR SNRs emission mechanisms. Aided by archival radio data, we find that most candidates detected show IR-to-radio ratios consistent with SNRs with a few exceptions displaying ratios seen in H II regions. Finally, we explore the connection between the IR and the high-energy X-ray emission of SNRs and find a good morphological association between the 24 μm emission and the X-ray features in younger remnants. The IR power is often greater.