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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

An optical particle counter for the regular application onboard a passenger aircraft: instrument modification, characterization and results from the first year of operation / Ein optischer Partikelzähler für den regelmäßigen Einsatz auf einem Passagierflugzeug: Instrumentenmodifikation, Charakterisierung und Ergebnisse aus dem ersten Messjahr

Weigelt, Andreas 08 July 2015 (has links) (PDF)
To understand the contribution of aerosol particles to radiative forcing and heterogeneous chemical processes in the upper troposphere and lowermost stratosphere (UT/LMS), the knowledge of the particle size distribution is mandatory. Unfortunately, measurements in the UT/LMS are costly. Research aircrafts are expensive and thus their application is limited in time and space. Satellite remote sensing measurements provide a good temporal and spatial (horizontal) coverage, but only a limited vertical resolution and currently cannot resolve the particle size distribution. Therefore, within this thesis an optical particle counter (OPC) unit was modified for the application onboard a passenger long-haul aircraft within the CARIBIC project (www.caribic-atmospheric.com). The CARIBIC OPC unit provides regular and cost-efficient particle size distribution measurements of accumulation mode particles in the UT/LMS. In April 2010, the new OPC unit was installed for the first time onboard the Lufthansa Airbus A340 600 (D-AIHE) for the measurement of the volcanic ash cloud from the Eyjafjallajökull eruption (April to May 2010). Since June 2010 the OPC unit measures on usually four intercontinental flights per month the UT/LMS particle size distribution in the particle size range 125 to 1300 nm particle diameter. As the data acquisition stores the scattering raw signal and all housekeeping data as well, during the post flight data analysis the temporal- and size channel resolution can be flexible set. Within this work the data were analyzed with 32 size channels and 300 seconds. As aircraft-borne measurements are always time-consuming, the development of the OPC unit and the analysis routine, as well as its characterization and certification took more than two thirds of the total working time of this thesis. Therefore, the analysis of the data is limited to the first year of regular measurements until May 2011. Nevertheless, this dataset is sufficient to demonstrate the scientific relevance of these measurements. To validate the OPC data, a comparison to particle size distributions measured from board research aircraft was carried out. The analysis of the volcanic ash flights in April and May 2010 showed strongly enhanced particle mass concentrations inside the plumes and agreed in some regions very well to the particle mass concentration predicted by a dispersion model. A further case study shows the occurrence of a surprising large (1000 km) and high concentrated pollution plume over eastern Asia close to Osaka (Japan). Inside the plume the highest particle number- and mass concentrations measured with the OPC unit in the analysis period were observed (except volcanic ash flights). A detailed analysis of the in parallel measured trace gasses as well as meteorological- and LIDAR data showed, the observed plume originate from biomass burning and industrial emissions in eastern China. A third case study gives a first attempt of a mass closure/validation between the particle masses derived by the CARIBIC OPC unit and the CARIBIC impactor particle samples. First statistical analyses to the vertical, meridional, and seasonal variation of the accumulation mode particle size distribution and therefrom derived parameter indicate a stratospheric vertical increasing gradient for the particle number- and mass concentration. In general in the mid-latitude LMS the concentration of accumulation mode particles was found to be on average 120% higher than in the mid-latitude UT. The mid-latitude LMS particle size distribution shows a seasonal variation with on average 120% higher concentrations during spring compared to fall. This results can be explained with general dynamics in the stratosphere (Brewer-Dobson Circulation) and in the tropopause region (stratosphere-troposphere-exchange, STE). An anti-correlation of gaseous mercury to the stratospheric particle surface area concentration (R²=0.97) indicates that most likely stratospheric aerosol particles do act as a sink for gaseous mercury. Finally, two comparisons of the OPC data to data from satellite remote sensing and a global aerosol model underline the OPC potential and the benefits of creating an in situ measured reference dataset. / Um die Rolle von Aerosolpartikeln beim Strahlungsantrieb und der heterogenen chemischen Prozessen in der oberen Troposphäre und untersten Stratosphäre (OT/US) verstehen zu können, ist es unabdingbar die Partikelgrößenverteilung zu kennen. Messungen der Partikelgrößenverteilung in dieser Region sind allerdings aufwendig. Der Einsatz von Forschungsflugzeugen ist teuer und deshalb zeitlich und räumlich nur begrenzt. Satellitenmessungen bieten zwar eine gute zeitliche und räumliche (horizontal) Abdeckung, aber nur eine begrenzte vertikale Auflösung. Weiterhin können bisherige Satellitenmessungen die Partikelgrößenverteilung nicht auflösen. Im Rahmen dieser Arbeit wurde deshalb ein optischer Partikelzähler (OPC) Messeinschub für den Einsatz an Bord eines Langstrecken-Passagierflugzeugs aufgebaut (CARIBIC Projekt, www.caribic-atmospheric.com). Mit diesem Messeinschub kann regelmäßig und kosteneffizient die Partikelgrößenverteilung des Akkumulationsmodes in der OT/US gemessen werden. Im April 2010 wurde der neue OPC Einschub erstmals an Bord des Lufthansa Airbus A340-600 (D-AIHE) installiert um die Vulkanasche der Eyjafjallajökull Eruption (April bis Mai 2010) zu messen. Seit Juni 2010 misst der OPC Einschub auf durchschnittlich vier Interkontinentalflügen pro Monat die Partikelgrößenverteilung der OT/US im Größenbereich zwischen 125 und 1300 nm Partikeldurchmesser. Während des Fluges speichert die Datenerfassung alle Rohsignale ab und ermöglicht dadurch eine nutzerspezifische Datenauswertung nach dem Flug (z. B. Anzahl der Größenkanäle oder Zeitauflösung). Im Rahmen dieser Arbeit wurden die Daten mit 32 Größenkanälen und 300 Sekunden analysiert. Da fluggetragene Messungen immer sehr aufwendig sind, beanspruchte die Entwicklung des OPC Einschubs und des Analysealgorithmus, sowie die Charakterisierung und Zertifizierung mehr als zwei Drittel der Gesamtarbeitszeit dieser Arbeit. Daher ist die Analyse der Messdaten auf das erste Jahr der regulären Messungen bis Mai 2011 beschränkt. Dennoch ist dieser Datensatz geeignet um die wissenschaftliche Relevanz dieser Messungen zu demonstrieren. Um die OPC-Daten zu validieren, wurde ein Vergleich mit bisherigen OPC Messungen von Bord Forschungsflugzeugen durchgeführt. Die Analyse der Vulkanascheflüge im April und Mai 2010 zeigte in der Abluftfahne stark erhöhte Partikelmassekonzentrationen, welche in einigen Vergleichsregionen sehr gut mit der Vorhersage eines Disperionsmodells übereinstimmten. Eine weitere Fallstudie zeigt das Auftreten einer überraschend großen (1000 km) und hoch konzentrierten Abluftfahne über Ostasien nahe Osaka (Japan). In der Abluftfahne wurde die im Analysezeitraum höchste mit dem CARIBIC OPC gemessene Partikelanzahl- und Massenkonzentration beobachtet (ausgenommen Vulkanascheflüge). Eine detaillierte Analyse der parallel gemessenen Spurengase, sowie meteorologischer Daten und LIDAR Profile zeigte, dass die beobachtete Abluftfahne eine Mischung aus Biomasseverbrennungs- und Industrieabgasen aus Ost-China war. Eine dritte Fallstudie stellt einen ersten Versuch einer Massenschließung/Validierung zwischen der aus den CARIBIC OPC-Daten abgeleiteten Partikelmasse und der Partikelmasse aus CARIBIC Impaktorproben dar. Erste statistische Analysen zur vertikalen, meridionalen und saisonalen Variabilität der Partikelgrößenverteilung im Akkumulationsmode und daraus abgeleiteten Parametern zeigen einen vertikal ansteigenden Gradienten für die Partikelanzahl- und Massenkonzentration. Generell war in der US der mittleren Breiten die Konzentration von Akkumulationsmode Partikeln im Mittel um 120% höher als in der OT der mittleren Breiten. Weiterhin wurde in der US der mittleren Breiten eine jahreszeitliche Schwankung gefunden. Im Frühling war die mit dem OPC gemessene Partikelkonzentrationen im Mittel um 120% höher als im Herbst. Diese Befunde lassen sich mit der atmosphärischen Dynamik in der Stratosphäre (Brewer-Dobson Zirkulation) und in der Tropopausenregion (Stratosphäre-Troposphäre-Austauschprozesse) erklären. Eine gefundene negative Korrelation von gasförmigen Quecksilber mit der stratosphärischen Partikeloberflächenkonzentration (R²=0.97) ist ein starker Indikator dafür, dass in der US Aerosolpartikel eine Senke für gasförmiges Quecksilber darstellen. Zum Abschluss unterstreichen zwei Vergleiche der OPC-Daten mit Satellitenmessungen und Ergebnissen eines globalen Aerosolmodels das Potential und den Nutzen der CARIBIC OPC Daten als in-situ gemessenen Referenzdatensatz.
72

Compressibility Of Various Coarse-grained Fill Materials In Dry And Wet Loading Conditions In Oedometer Test

Kayahan, Ahmet 01 January 2003 (has links) (PDF)
The use of coarse-grained fill materials has grown significantly in recent years especially on account of their use in dams and transportation networks. This study investigates compressibility of various coarse-grained fill materials in dry and wet loading conditions in oedometer test. Four materials were used in the experiments, which falls into GP, GW, GM and GC categories respectively. GP material is a weathered rock obtained from Eymir Lake region. This material was chosen especially to be able to investigate degradation and particle breakage due to compaction and compression. GW, GM and GC materials were obtained by using the material called &lsquo / bypass&rsquo / which is a fill material used in the construction of metro of Eryaman. Using these four materials, large-scale double oedometer tests were carried out to investigate compressibility in both dry and wet conditions. The double oedometer testing technique is used to investigate the effect of soaking on compressibility behaviour of compacted fill materials. Various compactive efforts were used in the compaction stage to investigate the effect of compactive effort on compressibility and degradation of the four gravelly materials. Gradations of the post-test samples were obtained and particle breakage due to compaction using various compactive efforts and particle breakage due to compression were determined. It is found that amount of compression does not necessarily depend on the dry density of the material and fine fraction is also a dominating property regarding the compressibility in coarse-grained fill materials. The vertical strains induced by soaking are on the order of 12% - 20% of the compression measured in dry loading case for the well-graded coarse-grained fill materials tested. Besides, there is significant particle breakage in the compaction process and no further particle breakage in the oedometer test for GP material.
73

Measuring Intrinsic Fluorescence Of Airborne Particles For Real-Time Monitoring Of Viable Bioaerosols

Agranovski, Victoria January 2004 (has links)
Development of the advanced, real-time methods for monitoring of bioaerosols is becoming increasingly important. At present, the Ultraviolet Aerodynamic Particle Sizer (UVAPS, Model 3312, TSI, St. Paul., MN) is the only commercially available method for in-situ, continuous measurements of viable airborne microorganisms. Research included in this thesis aimed towards comprehensive evaluation of the method over a wide range of operating conditions, linking the experimental results to the theoretical basis of its design and operation, and to developing a scientific basis for its application to real-time monitoring of bioaerosols. Specifically, due to a growing concern in the general community about the environmental and health aspects of biological aerosols originated from various types of agricultural operations including animal farming, this research was focussed on developing a research methodology/strategy for applying the method to the investigation of bioaerosols in the swine confinement buildings (SCB). Investigations under controlled laboratory conditions were primarily concerned with selectivity, sensitivity, counting efficiency, and detection limits of the spectrometer. This study also examined the effect of physiological state (metabolic activity) of bacteria on the performance characteristics of the method. The practical implications of the research findings are discussed in this thesis. Further field investigations undertaken on a pig farm advanced understanding of the UVAPS performance in the real-life environmental settings. The research also provided a new insight on the particle size distribution and the effect of on-farm-activities on aerosol load inside the SCBs, for both biological and non-biological aerosols. This study has proved that the UVAPS is a powerful tool for investigation of viable bioaerosols in the environment. However, this method is limited to detection of active metabolising bacteria that excludes dormant bacterial spores. In addition, the method is very sensitive to physiological state of bacteria and to the effect of adverse environmental conditions on metabolic activity of airborne bacteria, which may decrease the amount of the intrinsic fluorophores in the cells below sensitivity level iv of the monitor. Possible limitations of this technology include also the lack of selectivity and thus interferences from the non-microbial organic components of airborne particles. In addition, the sensitivity of the method is insufficient for monitoring viable bacteria in the environments with relatively low concentrations of bioaerosols. In order to increase sensitivity of the method, it would be desirable to concentrate the bioaerosols into a smaller volume with the aim of high-volume virtual impactors (aerosol concentrators) prior to the monitoring. Therefore, in the indoor environments where an application of the concentrator is not feasible, the utilisation of the UVAPS may be problematic. Due to the intrinsic limitations, the method is not recommended for the direct measurements of viable bioaerosols and should be used in conjunction with the conventional biosamplers for obtaining more realistic insights into the microbial air quality. Nevertheless, the UVAPS has been found to be an adequate method for the investigation of the dynamics of biological aerosols in real-time. Overall, this thesis contributes to the advancing of the understanding of the method and may assist in developing new, more advanced technologies for the real-time monitoring of viable bioaerosols, as well as in developing sampling strategies for the application of the method to various bioaerosol studies.
74

An investigation of rainfall characteristics, erosivity and soil erosion on Round Island, Mauritius

Calvert, Darren Rhett 02 1900 (has links)
Round Island is a small (208 ha) islet of volcanic origin located 22.5 km north east of mainland Mauritius and has been classified as a nature reserve since 1957. Two sites were chosen for the installation of environmental monitoring equipment. A series of Gerlach troughs were installed to capture surface sediment transported by runoff, which were used to document sediment yields and determine the particle size distribution. Overall, rainfall and erosivity on Round Island is far less, when compared to mainland Mauritius. However, erosivity from Round Island (2,314.76 MJ.mm.ha-1.h-1.yr-1) is slightly above the global average of 2,190 MJ.mm.ha-1.h-1.yr-1. In terms of sediment transport, the annual sediment movement rates for Round Island were established during this study (0.1248 t.ha-1.yr-1) and were found to be considerably lower than Mauritius (10 t.ha-1.yr-1), as well as other tropical island such as Kauai (0.86 t.ha-1.yr-1) and O’ahu (0.6 t.ha-1.yr-1). Thus, although the estimated rates of soil erosion are very low for humid tropical regions, these rates only reflect the contemporary environmental conditions and cognisance of the landscape history should be incorporated into assessments of soil erosion / Geography / M. Sc. (Geography)
75

Desenvolvimento de metodologia analítica e de sensoriamento remoto visando analisar os níveis de HPAs em partículas atmosféricas ultrafinas na Região Metropolitana de Porto Alegre

Agudelo Castañeda, Dayana Milena January 2014 (has links)
Nos últimos anos, a deterioração da qualidade do ar urbano devido ao material particulado atmosférico está recebendo atenção significativa e continuamente ameaça a qualidade de vida dos habitantes das áreas urbanas. A poluição do ar pelas partículas atmosféricas nas zonas urbanas é causada principalmente pelas emissões de fontes antropogênicas em sua maioria veiculares. Além disso, a poluição causada por partículas atmosféricas não está apenas relacionada com a sua concentração, mas também com a distribuição dos seus diferentes diâmetros. As partículas na fração estudada, < 1 μm, apresentam maior risco porque podem penetrar nos pulmões, afetam a função alveolar e ocasionam efeitos nocivos na saúde humana. Contudo, as partículas atmosféricas podem carregar diferentes compostos que são tóxicos e/ou cancerígenos, produzindo riscos para a saúde, como os Hidrocarbonetos policíclicos aromáticos – HPAs. Os HPAs são um grupo de diversos compostos orgânicos complexos, constituídos por carbono e hidrogênio junto com dois ou mais anéis benzênicos condensados. Portanto, foi desenvolvido um procedimento científico apto para estudar material particulado atmosférico < 1 μm (MP1) com a finalidade de analisar quantitativa e qualitativamente os HPAs associados a esta fração, a concentração em número das partículas e a distribuição de tamanho de partículas na Região Metropolitana de Porto Alegre usando técnicas analíticas e de sensoriamento remoto. As amostras foram coletadas em filtros de PTFE nos municípios de Sapucaia do Sul e Canoas, pertencentes à Região Metropolitana de Porto Alegre, usando o amostrador sequencial automático PM162M da Environnement S.A. As amostras foram extraídas utilizando o método EPA TO-13A para analisar 16 HPAs, utilizando um cromatógrafo gasoso acoplado a um espectrômetro de massa (CG-EM). A distribuição do tamanho de partícula nas frações PR1 (0.3-1.0 μm), PR2.5 (1.0-2.5 μm) e PR10 (2.5-10 μm) foi obtida utilizando o analisador de partículas CPM em Sapucaia do Sul. Os dados das concentrações de poluentes atmosféricos relacionados com MP10, óxidos de nitrogênio (NO, NOx, NO2) e ozônio (O3) foram obtidos utilizando os analisadores MP101M, AC32M e O342M da Environnement, respectivamente. Dados das variáveis meteorológicas como velocidade do vento, direção do vento, umidade relativa, radiação solar e temperatura ambiente foram medidos simultaneamente de modo concomitante. Os espectros de emissividade e transmitância, através da espectroscopia no infravermelho, foram obtidos utilizando espectrômetro FTIR D&P e o BOMEM MB-series FTIR-Hartmann & Braun Michelson, respectivamente. A determinação dos resultados usando cromatografia mostraram que no inverno as concentrações de HPAs foram significativamente maiores do que no verão, mostrando assim uma variação sazonal. A identificação das fontes de emissão, aplicando razões diagnóstico, confirmou que os HPAs na área de estudo são originários de fontes móveis, especialmente, das emissões de diesel e da gasolina. A análise por modelo receptor PMF também mostrou a contribuição dessas duas fontes principais, seguido pela combustão de carvão, combustão incompleta/petróleo não queimado e da combustão de madeira. Os fatores tóxicos equivalentes foram calculados para caracterizar o risco de câncer por exposição ao HPA em amostras de MP1, e benzo[a]pireno e dibenzo[ah] antraceno que dominaram os níveis de BaPeq. Com exceção do O3, a análise de tendência do NO, NO2 e NOx mostrou um aumento da concentração destes compostos no inverno. Também a correlação destes poluentes com os parâmetros meteorológicos permitiu evidenciar a influência das fontes móveis na área de estudo. Os resultados das assinaturas espectrais no infravermelho das amostras de MP1 comparando com os padrões e com outros trabalhos mostraram que o maior número de bandas de fortes intensidades ocorreu na região espectral de 680-900 cm-1, devido às deformações angulares CC fora do plano e deformações angulares CH fora do plano dos HPAs. Bandas de média intensidade na região de 2900-3050 cm-1, também foram observadas devido ao estiramento CH, característico de compostos aromáticos. A presente pesquisa foi o ponto de partida para obter um banco de dados das concentrações de HPAs associados à fração MP1 e dos poluentes NOx/NO2/NO/MP10/O3; caracterizar a distribuição de tamanho de partículas atmosféricas, que são de grande importância e preocupação atual; avaliar a sua variação sazonal e sua relação com as condições meteorológicas usando técnicas estatísticas; e aprofundar o conhecimento do comportamento espectral dos HPAs, poluentes cancerígenos e mutagênicos, presentes no material particulado atmosférico na fração fina e ultrafina. / In recent years, the urban air quality deterioration due to atmospheric particulate matter is receiving significant attention; also, it continually threatens the life quality of urban residents. Air pollution by atmospheric particles in urban areas is mainly caused by emissions from anthropogenic sources, mostly vehicular sources. Moreover, the pollution caused by atmospheric particles is not only related to its concentration, but also with the size distribution. The particles studied in the fraction <1μm have a greater risk because they can penetrate into the lungs, affect cellular function and cause adverse effects on human health. However, atmospheric particles can carry different compounds that are toxic and/or carcinogenic, producing health risks, such as polycyclic aromatic hydrocarbons - PAH. PAHs are a group of several complex organic compounds consisting of carbon and hydrogen along with two or more fused benzene rings. Consequently, a scientific procedure was developed to study the atmospheric particulate matter < 1 μm (PM1) in order to analyze qualitatively and quantitatively the PAHs associated with this fraction, also the particle number concentration and particle size distribution in the Metropolitan Region of Porto Alegre using remote sensing techniques. PM1 samples were collected in PTFE filters in Sapucaia South and Canoas sites, in the Metropolitan Region of Porto Alegre using the automatic sequential sampler PM162M of Environnement S.A. The samples were extracted using the EPA Method TO-13A and 16 PAHs were analyzed using a gas chromatograph coupled to a mass spectrometer (GC-MS). The particle size distribution of fractions PR1 (0.3 - 1.0 μm), PR2.5 (1.0 - 2.5 μm) and PR10 (2.5 – 10 μm) was obtained using the particulate analyzer CPM. The data of related air pollutants concentrations such as PM10, nitrogen oxides (NO, NOx, NO2), ozone (O3) were obtained using the analyzers MP101M, AC32M, O342M of Environnement, respectively. Data from meteorological variables, wind speed, wind direction, relative humidity, solar radiation and ambient temperature were continuously measured and simultaneously. The emissivity and transmittance spectra through infrared spectroscopy were obtained using FTIR spectrometer D&P and the Bomem MB-series FTIR-Hartmann & Braun Michelson, respectively. The results showed that in winter, the concentrations of PAHs were significantly higher than in summer, thus showing their seasonal variation. The identification of emission sources, applying diagnostic ratios confirmed that PAHs in the study area originate from mobile sources, especially diesel and gasoline emissions. The analysis by PMF receptor model also showed the contribution of these two sources, followed by coal combustion, incomplete combustion/unburned petroleum and wood combustion. The toxic equivalent factors were calculated to characterize the risk of cancer from PAH exposure to PM1.0 samples, and benzo[a]pyrene and dibenz[ah]pyrene dominated BaPeq levels. The trend analysis of O3, NO, NO2, NOx showed a trend of increased concentration at winter, except O3. Also the correlation of these pollutants with meteorological parameters has demonstrated the influence of mobile sources in the study area. The results of the IR spectral signatures of the PM1 samples compared to the standards and other studies showed that the greatest number of strong bands occurred in the spectral region of 680-900 cm- 1 due to the CC out-of-plane angular deformation and CH out-of-plane angular deformation of PAHs. Bands of medium intensity in the 2900-3050 cm-1 region were also observed due to the CH stretch, characteristic of aromatic compounds. This research was the starting point for a concentrations database of PAHs associated fraction PM1 and pollutants NOx/NO2/NO/PM10/O3, characterize the size distribution of atmospheric particles that are of great importance and current concern. Furthermore, to assess their seasonal variation and its relationship with meteorological conditions, using statistical techniques. Also to deepen the knowledge of the spectral behavior of PAHs that are carcinogenic and mutagenic pollutants present in atmospheric particulate matter in the fine and ultrafine fraction.
76

Desenvolvimento de metodologia analítica e de sensoriamento remoto visando analisar os níveis de HPAs em partículas atmosféricas ultrafinas na Região Metropolitana de Porto Alegre

Agudelo Castañeda, Dayana Milena January 2014 (has links)
Nos últimos anos, a deterioração da qualidade do ar urbano devido ao material particulado atmosférico está recebendo atenção significativa e continuamente ameaça a qualidade de vida dos habitantes das áreas urbanas. A poluição do ar pelas partículas atmosféricas nas zonas urbanas é causada principalmente pelas emissões de fontes antropogênicas em sua maioria veiculares. Além disso, a poluição causada por partículas atmosféricas não está apenas relacionada com a sua concentração, mas também com a distribuição dos seus diferentes diâmetros. As partículas na fração estudada, < 1 μm, apresentam maior risco porque podem penetrar nos pulmões, afetam a função alveolar e ocasionam efeitos nocivos na saúde humana. Contudo, as partículas atmosféricas podem carregar diferentes compostos que são tóxicos e/ou cancerígenos, produzindo riscos para a saúde, como os Hidrocarbonetos policíclicos aromáticos – HPAs. Os HPAs são um grupo de diversos compostos orgânicos complexos, constituídos por carbono e hidrogênio junto com dois ou mais anéis benzênicos condensados. Portanto, foi desenvolvido um procedimento científico apto para estudar material particulado atmosférico < 1 μm (MP1) com a finalidade de analisar quantitativa e qualitativamente os HPAs associados a esta fração, a concentração em número das partículas e a distribuição de tamanho de partículas na Região Metropolitana de Porto Alegre usando técnicas analíticas e de sensoriamento remoto. As amostras foram coletadas em filtros de PTFE nos municípios de Sapucaia do Sul e Canoas, pertencentes à Região Metropolitana de Porto Alegre, usando o amostrador sequencial automático PM162M da Environnement S.A. As amostras foram extraídas utilizando o método EPA TO-13A para analisar 16 HPAs, utilizando um cromatógrafo gasoso acoplado a um espectrômetro de massa (CG-EM). A distribuição do tamanho de partícula nas frações PR1 (0.3-1.0 μm), PR2.5 (1.0-2.5 μm) e PR10 (2.5-10 μm) foi obtida utilizando o analisador de partículas CPM em Sapucaia do Sul. Os dados das concentrações de poluentes atmosféricos relacionados com MP10, óxidos de nitrogênio (NO, NOx, NO2) e ozônio (O3) foram obtidos utilizando os analisadores MP101M, AC32M e O342M da Environnement, respectivamente. Dados das variáveis meteorológicas como velocidade do vento, direção do vento, umidade relativa, radiação solar e temperatura ambiente foram medidos simultaneamente de modo concomitante. Os espectros de emissividade e transmitância, através da espectroscopia no infravermelho, foram obtidos utilizando espectrômetro FTIR D&P e o BOMEM MB-series FTIR-Hartmann & Braun Michelson, respectivamente. A determinação dos resultados usando cromatografia mostraram que no inverno as concentrações de HPAs foram significativamente maiores do que no verão, mostrando assim uma variação sazonal. A identificação das fontes de emissão, aplicando razões diagnóstico, confirmou que os HPAs na área de estudo são originários de fontes móveis, especialmente, das emissões de diesel e da gasolina. A análise por modelo receptor PMF também mostrou a contribuição dessas duas fontes principais, seguido pela combustão de carvão, combustão incompleta/petróleo não queimado e da combustão de madeira. Os fatores tóxicos equivalentes foram calculados para caracterizar o risco de câncer por exposição ao HPA em amostras de MP1, e benzo[a]pireno e dibenzo[ah] antraceno que dominaram os níveis de BaPeq. Com exceção do O3, a análise de tendência do NO, NO2 e NOx mostrou um aumento da concentração destes compostos no inverno. Também a correlação destes poluentes com os parâmetros meteorológicos permitiu evidenciar a influência das fontes móveis na área de estudo. Os resultados das assinaturas espectrais no infravermelho das amostras de MP1 comparando com os padrões e com outros trabalhos mostraram que o maior número de bandas de fortes intensidades ocorreu na região espectral de 680-900 cm-1, devido às deformações angulares CC fora do plano e deformações angulares CH fora do plano dos HPAs. Bandas de média intensidade na região de 2900-3050 cm-1, também foram observadas devido ao estiramento CH, característico de compostos aromáticos. A presente pesquisa foi o ponto de partida para obter um banco de dados das concentrações de HPAs associados à fração MP1 e dos poluentes NOx/NO2/NO/MP10/O3; caracterizar a distribuição de tamanho de partículas atmosféricas, que são de grande importância e preocupação atual; avaliar a sua variação sazonal e sua relação com as condições meteorológicas usando técnicas estatísticas; e aprofundar o conhecimento do comportamento espectral dos HPAs, poluentes cancerígenos e mutagênicos, presentes no material particulado atmosférico na fração fina e ultrafina. / In recent years, the urban air quality deterioration due to atmospheric particulate matter is receiving significant attention; also, it continually threatens the life quality of urban residents. Air pollution by atmospheric particles in urban areas is mainly caused by emissions from anthropogenic sources, mostly vehicular sources. Moreover, the pollution caused by atmospheric particles is not only related to its concentration, but also with the size distribution. The particles studied in the fraction <1μm have a greater risk because they can penetrate into the lungs, affect cellular function and cause adverse effects on human health. However, atmospheric particles can carry different compounds that are toxic and/or carcinogenic, producing health risks, such as polycyclic aromatic hydrocarbons - PAH. PAHs are a group of several complex organic compounds consisting of carbon and hydrogen along with two or more fused benzene rings. Consequently, a scientific procedure was developed to study the atmospheric particulate matter < 1 μm (PM1) in order to analyze qualitatively and quantitatively the PAHs associated with this fraction, also the particle number concentration and particle size distribution in the Metropolitan Region of Porto Alegre using remote sensing techniques. PM1 samples were collected in PTFE filters in Sapucaia South and Canoas sites, in the Metropolitan Region of Porto Alegre using the automatic sequential sampler PM162M of Environnement S.A. The samples were extracted using the EPA Method TO-13A and 16 PAHs were analyzed using a gas chromatograph coupled to a mass spectrometer (GC-MS). The particle size distribution of fractions PR1 (0.3 - 1.0 μm), PR2.5 (1.0 - 2.5 μm) and PR10 (2.5 – 10 μm) was obtained using the particulate analyzer CPM. The data of related air pollutants concentrations such as PM10, nitrogen oxides (NO, NOx, NO2), ozone (O3) were obtained using the analyzers MP101M, AC32M, O342M of Environnement, respectively. Data from meteorological variables, wind speed, wind direction, relative humidity, solar radiation and ambient temperature were continuously measured and simultaneously. The emissivity and transmittance spectra through infrared spectroscopy were obtained using FTIR spectrometer D&P and the Bomem MB-series FTIR-Hartmann & Braun Michelson, respectively. The results showed that in winter, the concentrations of PAHs were significantly higher than in summer, thus showing their seasonal variation. The identification of emission sources, applying diagnostic ratios confirmed that PAHs in the study area originate from mobile sources, especially diesel and gasoline emissions. The analysis by PMF receptor model also showed the contribution of these two sources, followed by coal combustion, incomplete combustion/unburned petroleum and wood combustion. The toxic equivalent factors were calculated to characterize the risk of cancer from PAH exposure to PM1.0 samples, and benzo[a]pyrene and dibenz[ah]pyrene dominated BaPeq levels. The trend analysis of O3, NO, NO2, NOx showed a trend of increased concentration at winter, except O3. Also the correlation of these pollutants with meteorological parameters has demonstrated the influence of mobile sources in the study area. The results of the IR spectral signatures of the PM1 samples compared to the standards and other studies showed that the greatest number of strong bands occurred in the spectral region of 680-900 cm- 1 due to the CC out-of-plane angular deformation and CH out-of-plane angular deformation of PAHs. Bands of medium intensity in the 2900-3050 cm-1 region were also observed due to the CH stretch, characteristic of aromatic compounds. This research was the starting point for a concentrations database of PAHs associated fraction PM1 and pollutants NOx/NO2/NO/PM10/O3, characterize the size distribution of atmospheric particles that are of great importance and current concern. Furthermore, to assess their seasonal variation and its relationship with meteorological conditions, using statistical techniques. Also to deepen the knowledge of the spectral behavior of PAHs that are carcinogenic and mutagenic pollutants present in atmospheric particulate matter in the fine and ultrafine fraction.
77

Desenvolvimento de metodologia analítica e de sensoriamento remoto visando analisar os níveis de HPAs em partículas atmosféricas ultrafinas na Região Metropolitana de Porto Alegre

Agudelo Castañeda, Dayana Milena January 2014 (has links)
Nos últimos anos, a deterioração da qualidade do ar urbano devido ao material particulado atmosférico está recebendo atenção significativa e continuamente ameaça a qualidade de vida dos habitantes das áreas urbanas. A poluição do ar pelas partículas atmosféricas nas zonas urbanas é causada principalmente pelas emissões de fontes antropogênicas em sua maioria veiculares. Além disso, a poluição causada por partículas atmosféricas não está apenas relacionada com a sua concentração, mas também com a distribuição dos seus diferentes diâmetros. As partículas na fração estudada, < 1 μm, apresentam maior risco porque podem penetrar nos pulmões, afetam a função alveolar e ocasionam efeitos nocivos na saúde humana. Contudo, as partículas atmosféricas podem carregar diferentes compostos que são tóxicos e/ou cancerígenos, produzindo riscos para a saúde, como os Hidrocarbonetos policíclicos aromáticos – HPAs. Os HPAs são um grupo de diversos compostos orgânicos complexos, constituídos por carbono e hidrogênio junto com dois ou mais anéis benzênicos condensados. Portanto, foi desenvolvido um procedimento científico apto para estudar material particulado atmosférico < 1 μm (MP1) com a finalidade de analisar quantitativa e qualitativamente os HPAs associados a esta fração, a concentração em número das partículas e a distribuição de tamanho de partículas na Região Metropolitana de Porto Alegre usando técnicas analíticas e de sensoriamento remoto. As amostras foram coletadas em filtros de PTFE nos municípios de Sapucaia do Sul e Canoas, pertencentes à Região Metropolitana de Porto Alegre, usando o amostrador sequencial automático PM162M da Environnement S.A. As amostras foram extraídas utilizando o método EPA TO-13A para analisar 16 HPAs, utilizando um cromatógrafo gasoso acoplado a um espectrômetro de massa (CG-EM). A distribuição do tamanho de partícula nas frações PR1 (0.3-1.0 μm), PR2.5 (1.0-2.5 μm) e PR10 (2.5-10 μm) foi obtida utilizando o analisador de partículas CPM em Sapucaia do Sul. Os dados das concentrações de poluentes atmosféricos relacionados com MP10, óxidos de nitrogênio (NO, NOx, NO2) e ozônio (O3) foram obtidos utilizando os analisadores MP101M, AC32M e O342M da Environnement, respectivamente. Dados das variáveis meteorológicas como velocidade do vento, direção do vento, umidade relativa, radiação solar e temperatura ambiente foram medidos simultaneamente de modo concomitante. Os espectros de emissividade e transmitância, através da espectroscopia no infravermelho, foram obtidos utilizando espectrômetro FTIR D&P e o BOMEM MB-series FTIR-Hartmann & Braun Michelson, respectivamente. A determinação dos resultados usando cromatografia mostraram que no inverno as concentrações de HPAs foram significativamente maiores do que no verão, mostrando assim uma variação sazonal. A identificação das fontes de emissão, aplicando razões diagnóstico, confirmou que os HPAs na área de estudo são originários de fontes móveis, especialmente, das emissões de diesel e da gasolina. A análise por modelo receptor PMF também mostrou a contribuição dessas duas fontes principais, seguido pela combustão de carvão, combustão incompleta/petróleo não queimado e da combustão de madeira. Os fatores tóxicos equivalentes foram calculados para caracterizar o risco de câncer por exposição ao HPA em amostras de MP1, e benzo[a]pireno e dibenzo[ah] antraceno que dominaram os níveis de BaPeq. Com exceção do O3, a análise de tendência do NO, NO2 e NOx mostrou um aumento da concentração destes compostos no inverno. Também a correlação destes poluentes com os parâmetros meteorológicos permitiu evidenciar a influência das fontes móveis na área de estudo. Os resultados das assinaturas espectrais no infravermelho das amostras de MP1 comparando com os padrões e com outros trabalhos mostraram que o maior número de bandas de fortes intensidades ocorreu na região espectral de 680-900 cm-1, devido às deformações angulares CC fora do plano e deformações angulares CH fora do plano dos HPAs. Bandas de média intensidade na região de 2900-3050 cm-1, também foram observadas devido ao estiramento CH, característico de compostos aromáticos. A presente pesquisa foi o ponto de partida para obter um banco de dados das concentrações de HPAs associados à fração MP1 e dos poluentes NOx/NO2/NO/MP10/O3; caracterizar a distribuição de tamanho de partículas atmosféricas, que são de grande importância e preocupação atual; avaliar a sua variação sazonal e sua relação com as condições meteorológicas usando técnicas estatísticas; e aprofundar o conhecimento do comportamento espectral dos HPAs, poluentes cancerígenos e mutagênicos, presentes no material particulado atmosférico na fração fina e ultrafina. / In recent years, the urban air quality deterioration due to atmospheric particulate matter is receiving significant attention; also, it continually threatens the life quality of urban residents. Air pollution by atmospheric particles in urban areas is mainly caused by emissions from anthropogenic sources, mostly vehicular sources. Moreover, the pollution caused by atmospheric particles is not only related to its concentration, but also with the size distribution. The particles studied in the fraction <1μm have a greater risk because they can penetrate into the lungs, affect cellular function and cause adverse effects on human health. However, atmospheric particles can carry different compounds that are toxic and/or carcinogenic, producing health risks, such as polycyclic aromatic hydrocarbons - PAH. PAHs are a group of several complex organic compounds consisting of carbon and hydrogen along with two or more fused benzene rings. Consequently, a scientific procedure was developed to study the atmospheric particulate matter < 1 μm (PM1) in order to analyze qualitatively and quantitatively the PAHs associated with this fraction, also the particle number concentration and particle size distribution in the Metropolitan Region of Porto Alegre using remote sensing techniques. PM1 samples were collected in PTFE filters in Sapucaia South and Canoas sites, in the Metropolitan Region of Porto Alegre using the automatic sequential sampler PM162M of Environnement S.A. The samples were extracted using the EPA Method TO-13A and 16 PAHs were analyzed using a gas chromatograph coupled to a mass spectrometer (GC-MS). The particle size distribution of fractions PR1 (0.3 - 1.0 μm), PR2.5 (1.0 - 2.5 μm) and PR10 (2.5 – 10 μm) was obtained using the particulate analyzer CPM. The data of related air pollutants concentrations such as PM10, nitrogen oxides (NO, NOx, NO2), ozone (O3) were obtained using the analyzers MP101M, AC32M, O342M of Environnement, respectively. Data from meteorological variables, wind speed, wind direction, relative humidity, solar radiation and ambient temperature were continuously measured and simultaneously. The emissivity and transmittance spectra through infrared spectroscopy were obtained using FTIR spectrometer D&P and the Bomem MB-series FTIR-Hartmann & Braun Michelson, respectively. The results showed that in winter, the concentrations of PAHs were significantly higher than in summer, thus showing their seasonal variation. The identification of emission sources, applying diagnostic ratios confirmed that PAHs in the study area originate from mobile sources, especially diesel and gasoline emissions. The analysis by PMF receptor model also showed the contribution of these two sources, followed by coal combustion, incomplete combustion/unburned petroleum and wood combustion. The toxic equivalent factors were calculated to characterize the risk of cancer from PAH exposure to PM1.0 samples, and benzo[a]pyrene and dibenz[ah]pyrene dominated BaPeq levels. The trend analysis of O3, NO, NO2, NOx showed a trend of increased concentration at winter, except O3. Also the correlation of these pollutants with meteorological parameters has demonstrated the influence of mobile sources in the study area. The results of the IR spectral signatures of the PM1 samples compared to the standards and other studies showed that the greatest number of strong bands occurred in the spectral region of 680-900 cm- 1 due to the CC out-of-plane angular deformation and CH out-of-plane angular deformation of PAHs. Bands of medium intensity in the 2900-3050 cm-1 region were also observed due to the CH stretch, characteristic of aromatic compounds. This research was the starting point for a concentrations database of PAHs associated fraction PM1 and pollutants NOx/NO2/NO/PM10/O3, characterize the size distribution of atmospheric particles that are of great importance and current concern. Furthermore, to assess their seasonal variation and its relationship with meteorological conditions, using statistical techniques. Also to deepen the knowledge of the spectral behavior of PAHs that are carcinogenic and mutagenic pollutants present in atmospheric particulate matter in the fine and ultrafine fraction.
78

Modelagem matemática de copolimerização em emulsão de acrilato de butila e estireno para determinação dos valores médios de peso molecular e distribuição de tamanho de partículas. / Mathematical modeling of emulsion copolymerization of N-buty acrylate and styrene accounting for average molecular weights and particle size distribution.

Rodrigo Vallejo Pereira 09 October 2015 (has links)
Um modelo matemático da reação de copolimerização em emulsão de acrilato de butila e estireno em reator batelada e semi-batelada isotérmico foi desenvolvido e apresentou bons resultados quando comparado a experimentos disponíveis em literatura científica. O modelo contemplou a solução do balanço populacional, tanto para a distribuição de tamanho de partículas quando para a distribuição média de radicais por partícula. Contemplou-se também a solução do balanço de momentos, para obtenção da massa molar média numérica e mássica. O problema descrito foi resolvido através da solução numérica de um conjunto de equações algébricodiferenciais e o balanço populacional foi resolvido pelo método dos pivots fixos. Foi possível validar com boa aderência a conversão dos monômeros, o diâmetro médio de partículas, número de partículas por litro de emulsão, número médio de radicais por partícula, a distribuição de tamanho de partículas e a massa molar média numérica e mássica ao longo do tempo para um conjunto de experimentos. / A mathematical model of emulsion copolymerization reaction of styrene and butyl acrylate for batch and semi-batch isothermal reactor was developed and presented good results when compared to experiments available in the scientific literature. The model included the solution of the population balance for both particle size distribution and average number of radicals per particle. The balances of moments of the molecular weight distribution are solved to obtain the weight- and numberaveraged molecular weight of the polymer. The problem described was solved by numerical solution of a set of algebraic-differential equations and the population balance was solved by the method of fixed pivots. The model prediction were validated with a set of experiments with respect to the changes of monomer conversion, average particle diameter, number of particles per liter of emulsion, average number of radicals per particle, particle size distribution, number- and weight-average molecular weight during process time.
79

Copolimerização em emulsão de estireno e acrilato de butila com alto teor de sólidos: estudo experimental e modelagem matemática do processo em reator semicontínuo. / Emulsion copolymerization of styrene and butyl acrylate with gigh solids contents: experimental study and mathematical modeling of the process in a semi-batch reactor.

Giovane Marinangelo 18 November 2010 (has links)
Neste trabalho estudou-se a copolimerização em emulsão de estireno e acrilato de butila em processo semicontínuo onde o produto final é um látex com alto teor de sólidos. Foi dado enfoque à distribuição de tamanhos de partículas do látex e seus efeitos no produto. Foi realizada uma série de experimentos de copolimerização em emulsão em um reator de vidro, empregando receitas com teores de sólidos de até 64% em massa. Durante os experimentos, amostras eram retiradas periodicamente do reator visando analisar o teor de polímeros (conversão dos monômeros) por gravimetria, a concentração de monômero residual por cromatografia gasosa headspace, o diâmetro médio das partículas por espectroscopia de espalhamento dinâmico de luz e a distribuição de tamanhos de partículas por microscopia eletrônica de transmissão. A viscosidade do látex final era obtida em viscosímetro Brookfield. Aplicando estratégias para renucleação de novas partículas no decorrer do processo, foram obtidos látices com distribuição bimodal de tamanhos de partículas e com viscosidades reduzidas. Aplicou-se um modelo matemático para descrever o processo, incluindo a evolução no tempo da distribuição de tamanhos de partículas, calculada a partir de equações de balanço populacional para as partículas e para os radicais dentro das partículas. Para a solução das equações empregou-se discretização por método de classes e a técnica de pivô fixo. O modelo tem apenas dois parâmetros ajustáveis, referentes às eficiências de captura de radicais por micelas e por partículas. Estes parâmetros foram ajustados para os dados experimentais de um ensaio, e usados, sem reajuste, para outros ensaios em condições diferentes. Os resultados do modelo mostraram boa adequação aos resultados experimentais. / The aim of this work was the study of the high solid contents emulsion copolymerization of styrene and butyl acrylate in semi-batch process. In this context the particle size distribution and its effects on the product viscosity was studied. Copolymerization reactions were carried out in a glass reactor, and recipes with solid contents up to 64 wt.% were used. During each run, samples are periodically taken from the reactor, and analysis are performed to measure the polymer content (monomer conversion) by gravimetry, the concentrations of the residual monomers by head-space gas chromatography, the average particle size by dynamic light scattering, and the particle size distribution by transmission electronic microscopy. The viscosity of the final emulsion is also measured using a Brookfield viscosimeter. By applying operating strategies to nucleate new particles along the process, latexes with bimodal particle size distributions and low viscosities were obtained. A mathematical model was employed for simulating the polymerization process, including the evolution of the particle size distribution along the process, calculated from population balance equations for the particles and the radicals inside the particles. The numerical solution was obtained using the discretized population balance equations by the method of classes and the fixed pivot technique. The model has only two adjustable parameters, the efficiencies for radical capture by micelles and by particles. These two parameters were fitted to the experimental data of one run and used, without further readjustment, for other runs under different conditions. The model results presented satisfactory agreement with the experimental data.
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Helkrossad betongballast : Rekommenderade inställningar på vindsikten vid varierande fuktkvot i bergtäkten Vikan kross

Ström, Pär January 2017 (has links)
Skanskas bergtäkt, Vikan kross, i Göteborg producerar ett ersättningsmaterial till naturgruset i form av helkrossad betongballast. Utvinningen av naturgrus ska fasas ut eftersom det utvinns från grusåsar vilket är negativt för naturen då grusåsarna renar vatten och fungerar som naturliga vattenreservoarer. Historiskt sett har naturgruset använts till betongtillverkning under en väldigt lång tid och år 2013 investerade Vikan kross i en anläggning för att kunna producera helkrossad betongballast och på så vis fasa ut naturgruset från deras betongtillverkning. År 2014 stod anläggningen klar för att börja tillverka helkrossad betongballast. En lång uppstartsperiod där många tester utfördes för att få den helkrossade betongballasten att efterlikna naturgruset i form och egenskaper. I dagsläget producerar Vikan kross en bra ersättningsprodukt till naturgruset men produktionsledning har kommit underfund med att fuktkvoten på det ingående materialet till vindsikten har en stor påverkan på slutprodukten. Skanska gav mig i uppdrag att undersöka hur vindsiktens inställningar bör justeras beroende på vilken fuktkvot det ingående materialet har för att kunna bibehålla en acceptabel kornstorleksfördelning. Skanska har även önskemål att mängden filler (ballastkorn mindre än 63 μm) i slutprodukten skall öka från den mängd som finns i slutprodukten i dagsläget. En provtagningsplan baserad på tidigare tester och erfarenheter upprättades för att på så vis kunna följa vägen fram till ett bra resultat. Metoden som använts är provtagning av det ingående materialet samt det utgående materialet från vindsikten. Materialen har analyserats med hjälp av siktanalyser där kornstorleksfördelning har tagits fram. Vindsiktens inställningar har sedan varierats och ytterligare provtagning samt analyser har genomförts. När vindsikten ansågs producera helkrossad betongballast med så bra kornstorleksfördelning som möjligt bevattnades det ingående materialet till vindsikten. Vatten tillfördes för att höja fuktkvoten och på så vis förstå hur vindsiktens inställningar bör justeras för att behålla kornstorleksfördelningen inom de gränsvärden som finns. Resultatet visar att om det ingående materialet till vindsikten har en avvikande fuktkvot (&gt; 1 vikt-%) är det möjligt att erhålla en kornstorleksfördelning som efterliknar den kornstorleksfördelning som erhålls när materialet har en normal fuktkvot (&lt; 1 vikt-%). Mängden filler har inte ökat i slutprodukten eftersom att den ingående mängden filler till vindsikten redan är så låg att den inte går att justera med hjälp av enbart vindsikten. Orsaken till att mängden filler är lägre än vad som tidigare observerats kopplas till bergets geologi. Det berg som krossats under testperioden var väldigt hårt och där med produceras en mindre mängd filler. För en ökad mängd filler i slutprodukten krävs en förändring i krossprocessen före vindsikten. / Skanska Asfalt och Betong AB is the owner of the quarry Vikan kross in Gothenburg. They produce manufactured sand as a replacement product for the natural sand that is used in todays fin aggregates for concrete production. The Swedish government is limiting the extraction of natural sand because of environmental reasons. In 2013 Vikan kross invested in a plant to produce manufactured sand thus phasing out the natural sand from their concrete production. In 2014 the plant was ready to start producing manufactured sand. Through a long start-up period, many tests were done to get the manufactured sand to mimic the natural sand as much as possible. Today Vikan kross is producing a good replacement product for the natural sand, but the production team has come to the conclusion that the moisture content in the input material to the air classifier has a major impact on the final product. Skanska assigned me to investigate how the air classifiers settings should be adjusted depending on the moister content of the input material in order to maintain an acceptable particle size distribution. Skanska also wished that the amount of fines (particles smaller than 63 μm) in the manufactured sand should increase from the amount present today. A plan based on previous tests and experiences was set up in order to reach a good result. The method used was to take tests of the input materials as well as the output materials from the air classifier. The materials have been analyzed by using sieving methods to determinate the particle size distribution. The settings of the air classifier were then adjusted and further tests and analysis was done. When the air classifier was producing manufactured sand with a particle size distribution as good as possible, the input material was watered. Water was added to raise the moisture content to understand how the settings of the air classifier should be adjusted to maintain a particle size distribution within the limit values. The result shows that if the input material to the air classifier has a deviating moisture content (&gt; 1 wt-%) it is possible to obtain a particle size distribution that mimics the particle size distribution obtained when the material has a normal moisture content (&lt;1 wt-%). The amount of fines has not increased in the manufactured sand because the amount of fines in the input material is already so low that it can’t be adjusted by only changing the settings of the air classifier. The reason for the amount of fines being lower than previously observed is linked to the geology of the material. The material that had been crushed during this test period was very hard and thus produced a small amount of fines. For an increased amount of fines in the manufactured sand, a change is necessary in the process prior to the air classifier.

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