A methodology was developed to dissect diesel particulate filters to study the time effect of loading for two different fuels: ULSD and a biodiesel blend. Filters loaded with soot from a diesel engine for exposure times of 1, 2, 5 and 10 hours were fractured and samples of filter substrates were analyzed using Raman spectroscopy and scanning electron microscopy. Observations revealed the sharp rise in pressure drop to be attributable to the clogging of the pores in the channel wall, leading to the formation of a pore-bridge. Cross sectional imaging of wall sections revealed this pore-bridge to be shallow, with significant particulate depositions limited to the first quarter of the depth of the filter walls. Images revealed increasingly dense deposits and the formation of coarse particles and soot cakes. Raman spectroscopy revealed no significant graphitization of the soot cake. The dissection methodology exhibits significant potential for future studies on DPFs.

No description available.

The need to limit sulphur dioxide, nitrous oxides and particulate matter emissions from fossil fuel combustion processes is now a major factor in the design, construction and operation of plants. Over the past 5 to 10 years, most developed countries have introduced legislations to control these. emissions. This report was done to investigate emissions of sulphur dioxide (S02), nitrogen oxides (NOx) and particulate matter from coal fired power plants. S02 emissions contribute to an air pollution load that has been found to be linked to respiratory and heart problems. It increases the formation of acid precipitation, called acid rain. NOx oxides to nitrogen dioxide (N02). N02 acts as an irritant to the respiratory tract, alveoli of the lungs and causes chest pains. Toxic elements concentrate on fine particulate matter because of their high surface-area to volume ratio. These particles penetrate and settle onto the lung wall, leading to respiratory disorders and lung diseases. Due to the strict legislative requirements, flue gas detoxification processes were investigated. They include: • Wet scrubbing • Spray dry scrubbing • Dual-alkali • Well man-Lord • Activated carbon • Magnesium oxides • Selective catalytic recovery • Circulating fluidised bed combustion • Electromembrane desulphurisation A study was done to show the possible cost implications associated with the wet scrubbing, spray dry scrubbing, selective catalytic recovery, circulating fluidised bed and electromembrane desulphurisation process. A variety of methods were used to calculate cost, due to costs being difficult to obtain. Most of the information was based on European, Asian and American installations. The objective of this economic analysis was to compare the different technologies. Because of the assumptions used, costs were always "order of magnitude" estimates. Capital and operating costs were calculated for these technologies, but they can only be used as an indication of costs and to allow for comparisons between the technologies. The costs were converted using the January 2000 exchange rates. Due to this, costs may be more inflated than what would normally be expected due to equipment being purchased earlier than January 2000. Of the processes investigated, the circulating fluidised bed process was found to be the most economical. There is no inexpensive route for the removal of sulphur dioxide, nitrous oxides and particulate matter. The most suitable detoxification process will depend on the legislative requirements per country. South Africa is a signatory of the Montreal Protocol and the Framework for Climatic Change. Legislations for gaseous emissions were not considered a priority. Currently, Eskom's drive is to electrify townships rather than spend money on detoxification processes. However, future legislations may require more stringent control measures. / Thesis (M.Sc.Eng.)-University of Durban-Westville, 2000.

The total concentrations of particulate trace metals (Al. Cd, Co, Cu, Fe. Mn, Na. Ni. Pb, Zn) with analytical quality assurance, have been determined in atmospheric aerosols at two coastal sites, and during cruises in the Celtic Sea. Sampling at a site on the western English Channel covered 19 months and represents one of the most comprehensive time series of trace metals in atmospheric aerosols. Aerosol concentrations of Cd. Cu, Pb and Zn for the English Channel were lower than previously reported and Al. Co and Mn concentrations were similar to literature values. The elements were grouped according to behaviour such that Group 1 elements (Cd, Fe. Mn, Pb and Zn) displayed enhanced concentrations in autumn/winter 1994 and 1995. whereas Group 2 elements (Al, Co, Cu, Na and Ni) had enhanced concentrations during winter 1995 only. This was ascribed to source functions being dependant on wind direction with Group 1 elements being carried mainly by north easterly air masses, whereas Group 2 elements originated mainly with air masses from the south west. Dissolved trace metal (Al, Co, Cu, Ni, Pb) analyses were carried out on rain waters collected at the English Channel site. The rain water analyses showed that the soluble trace metal fraction was in the order Co = Cu > Ni >Pb > Na » Al and wet and dry depositional fluxes accounted for the differential behaviour and the solubility of aerosol trace metals on contact with sea water. Aerosol concentrations are also reported for the north western Mediterranean and the Celtic Sea. In the former location, the aerosol trace metal concentrations were lower than those reported in literature and in the Celtic Sea there was a gradient in the trace metal composition of the aerosol from land to open sea. The solid state speciation of Cd and Pb gave an increasingly matrix-bound fraction in the order north western Mediterranean < western English Channel < Celtic Sea and the Celtic Sea aerosols had the greatest sea water solubilities of all elements, except Ni. Concentrations of Cu, Ni and Pb in English Channel aerosols, rain waters and the fraction partitioning from aerosols on contact with sea water, together with sea water concentrations from the literature, were used to devise a trace metal flux model for the English Channel. The model showed that of the total trace metal fluxes into the English Channel, the atmospheric fluxes were in the order of importance Pb > Cu > Ni. The overall budgets revealed discrepancies in the mass balances, which were identified as sediment-water exchange for Ni and Pb and adsorption onto particles for Cu. These budget calculations provide a basis for the development of more advanced modelling concepts involving coupled atmosphere-ocean interactions.

Various additions are used in rubber compounds to accelerate mixing with particulate fillers and to improve behaviour in subsequent processing operations. Cationic surfactants of general structure [RNH2(CH2)3NH3]2+ 2[R'COO] can be used in rubber processing as multifunctional additives (MFA) which act as processing aids, accelerators and mould releasing agents. However, with all these beneficial properties an adverse effect of decreased scorch time was observed when N–tallow–1,3 diaminopropane dioleate (EN444) was used in the filled natural rubber compound.

Passenger vehicle disk brakes produce large amounts of wear debris that needs to be analyzed to verify its environmental and health impact because its effects are amplified by the massive extent of vehicular transportation around the world. An efficient and thorough method for wear debris analysis should be derived from this research to assist brake manufacturers and researchers in understanding the characteristics of wear particulates being released from current brake materials. In addition, a test method allowing inspection of brake formulations in development phase should be provided and several model "environmentally friendly" brake lining materials should be developed. The most hazardous constituents in a known brake lining formula should be replaced with non-hazardous materials that will obtain performance specifications comparable to the original formula. The brake manufacturing industry and general public should be notified of important findings from this research. Model brake linings fabricated on-site with known constituents were run through an AO4D performance dynamometer test to collect airborne and non-airborne wear debris that is comparable to wear debris produced by an average passenger vehicle. Based on previous experience with analysis of brake linings, this wear debris will be analyzed with scanning electron microscopy equipped with energy dispersive X-ray microanalysis (SEM-EDX), transmission electron microscopy with EDX (TEM-EDX), X-ray diffraction (XRD), polarized light microscopy (PLM), X-ray fluorescence (XRF), and laser scattering particle size distribution analyzer (LSPSDA). Research presented in this report indicates clearly that the previous work published by several groups is lacking sufficient information and the findings should be corrected. For instance the particle size distribution detected by particle size analyzers and impactors (recommended by EPA) is not accurate and TEM as well as SEM studies allowing direct observation of wear particles revealed considerable differences between sizes detected by these analyzers and realistic particle size. EDX in combination with XRF and XRD allows for reliable identification of chemical species and crystalline phases present in wear debris. True airborne wear debris should be sampled from brake exhaust from an appropriate distance. Degummed hemp shows promising results as a copper replacement in low-metallic friction material.

Made available in DSpace on 2014-06-11T19:29:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-06-07Bitstream added on 2014-06-13T19:38:00Z : No. of bitstreams: 1 azevedo_rc_me_araiq.pdf: 304556 bytes, checksum: ded49f14a2e14cead8af1a701b99e4ec (MD5) / Os hidrocarbonetos policíclicos aromáticos nitrados (NHPAs) constituem a classe de compostos aromáticos que têm pelo menos um grupo nitro (-NO2) ligado à cadeia aromática de um hidrocarboneto policíclico aromático (HPA). Nos anos 70 a descoberta das propriedades mutagênicas destes compostos, presentes em material particulado atmosférico e na exaustão de motores a diesel, aumentaram o interesse científico sobre a ocorrência dos mesmos no ambiente. Estes compostos, como os HPAs, estão associados a fontes de combustão como automóveis, sistemas de aquecimento (baseados na queima de biomassa ou de combustíveis fósseis); queima de biomassa (cigarro, florestas, culturas agrícolas, etc), por causa disso pode-se prever que tenham uma distribuição abrangente no ambiente. Os NHPAs são produtos da reação dos HPAs com óxidos de nitrogênio na atmosfera, apresentando-se em concentrações muito baixas neste compartimento ambiental. A análise de NHPAs é muito difícil, principalmente pelos artefactos de amostragem e pela interferência analítica causada por HPAs e outros compostos. Assim sendo, a investigação de métodos alternativos que sejam sensíveis e seletivos são de extrema importância na determinação de NHPAs em amostras atmosféricas. Neste trabalho estudou-se um método para determinação de 1-nitropireno em material particulado proveniente da queima de cana-de-açúcar. O método inclui a redução do grupo nitro a amino, com posterior determinação por HPLC/fluorescência. O método proposto tem limite de detecção de 0,930ng mL-1 e limite de determinação de 1,250ng mL-1, apresentando recuperação entre 77,00 e 86,34%, para 5,00 e 50,00ng mL-1 respectivamente. / Nitrated Polycyclic Aromatic Hydrocarbons (NPAHs) are the class of aromatic compounds with at least one nitro group (-NO2) enhanced to aromatic chain of a Polycyclic Aromatic Hydrocarbon (PAH). In 70’s the discovery of mutagenic properties of these compounds present in atmospheric particulate matter and in gas exhaust of diesel motors are increased the scientific interess on occurrence of NPAHs into environment. These compounds, as PAHs, are associated with combustion sources as automobiles; harming systems (biomass and combustible based); burning of biomass (cigarette, florest, agricultural cultures, etc), because this they have a ubicous dissemination on environment. NPAHs are product of reaction of PAHs with nitrogen oxides on atmosphere, and they are present there at very low concentrations. The analysis of NPAHs in atmospheric samples is very difficult, because of artefacts of sampling process and PAH and other compounds interference on analytical determination. Because this, investigation of alternative methods sensitive and selective is necessary for NPAHs determination in atmospheric samples. In this work is studied a method for determination of 1-nitropyrene from particulate matter of sugar cane burning. The method include reduction of nitro group to amino, and analysis by HPLC/ Fluorescence. The proposed method has detection limit of 0, 930ng mL-1 and quantification limit of .1,250ng mL-1 showing recovery ranged between 77,00 and 86,34% for concentrations of 5,00 and 50,00ng mL-1, respectively.

No description available.

Peatlands are an important store of soil carbon, play a vital role in global carbon cycling, and can also act as sinks of atmospherically deposited heavy metals. Large areas of the UK’s blanket peat are significantly degraded and actively eroding, which negatively impacts carbon and pollutant storage. The restoration of eroding UK peatlands is a major conservation concern, and over the last decade measures have been taken to control erosion and restore large areas of degraded peat. In severely eroded peatlands, topography is highly variable, and an appreciation of geomorphological form and process is key in understanding the controls on peatland function, and in mitigating the negative impacts of peatland erosion. The blanket peats of the Peak District, Southern Pennines, UK, embody many problems and pressures faced by peatlands globally, and are amongst the most heavily eroded and contaminated in the world. The near-surface layer of the peat is contaminated by high concentrations of anthropogenically derived, atmospherically deposited heavy metals, which are released into the fluvial system as a consequence of widespread erosion. Whilst not desirable, this legacy of lead pollution and its release, offer a unique opportunity to trace peatland sediment movements and thus investigate the controls on sediment and contaminant mobility. A suite of established field, analytical and modelling techniques have been modified and adapted for use in peatland environments: (i) by incorporating a simple correction for moisture content, field portable XRF has been shown to be an accurate, cost-effective, and rapid tool for assessing in situ lead concentrations in wet organic sediments; (ii) a lightweight time integrated mass flux sampler has been developed for deployment at multiple remote peatland field sites, and has been used to explore spatial and temporal suspended sediment dynamics; and (iii) sediment source fingerprinting and numerical mixing models, traditionally used to determine sources of fine sediment in minerogenic systems, have been used to investigate suspended sediment composition in contaminated organic rich catchments. These modified methods have been successfully employed in combination to address issues of sediment and contaminant release. Several mechanisms and controls have been shown to be important influences on sediment dynamics and Pb release across a range of spatial and temporal scales: (i) the presence of vegetation is key in stabilising the peat’s surface and trapping mobilised sediment; (ii) sediment preparation influences the timing of POC and Pb release; (iii) antecedent water tables may control the timing and the nature of sediment entering the fluvial system during storm events; and (iv) the degree of degradation influences both Pb storage and release. At the landscape scale, peatland restoration significantly mitigates sediment production in eroding peatlands and substantially reduces carbon and pollutant export. At the catchment scale, sediment preparation and hydrological connectivity are important controls on the magnitude and timing of sediment and lead fluxes from eroding peatland catchments. At the plot scale, complex small scale spatial patterns of contaminant storage in eroding headwater catchments can be explained by interactions between topographic setting and vegetation cover, and the mobilisation of sediment by wind and water. This deeper understanding of the multi-scalar dynamics of sediment movements in eroding peatlands is important in the context of: (i) the release and reworking of legacy contamination in organic rich systems; (ii) the response of blanket peats to climate change; (iii) informing future restoration strategies that aim to manage peatland sediment and contaminant fluxes.

Texas is the second largest state in U.S.A. based on geographical area, population and the economy. It is home to several large coastal urban areas with major industries and infrastructure supporting the fossil-fuel based energy sector. Most of the major cities on the state have been impacted by significant air pollution events over the past decade. Studies conducted in the southern coastal region of TX have identified long range transport as a major contributor of particulate matter (PM) pollution along with local emissions. Biomass burns, secondary sulfates and diesel emissions sources are comprise as the dominant mass of PM2.5 have been noted to be formed by the long range transport biomass from Central America. Thus, the primary objective of this study was to identify and quantify local as well as regional sources contributing to the PM pollution in the coastal area of Brownsville located along the Gulf of Mexico. Source apportionment techniques such as principal component analysis (PCA) and positive matrix factorization (PMF) were employed on the air quality monitoring data to identify and quantify local and regional sources affecting this coastal region. As a supplement to the PMF and PCA, conditional probability function (CPF) analysis and potential source contribution function (PSCF) analysis were employed to characterize the meteorological influences for PM events. PCA identified an optimal solution of 6 sources affecting the coastal area of Brownsville, while PMF resolved 8 sources for the same area. Biomass comingled with sea salt was identified to be the dominant contributor from the PCA analysis with 30.2% of the apportioned PM mass in Brownsville, meanwhile PMF account secondary sulfates I & II with 27.6%. the other common sources identified included, biomass burning, crustal dust, secondary sulfate, oil combustion, mobile sources and miscellaneous traffic sources.