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On the Manufacturing of SFF Based Tooling and Development of SLS Steel MaterialBoivie, Klas January 2004 (has links)
No description available.
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Synthèse du LiXFePO4 par voie fondue et l’étude de la couche de carbone sur LiFePO4Dahéron, Benjamin 03 1900 (has links)
Le LiFePO4 est un matériau prometteur pour les cathodes des batteries au lithium. Il possède une bonne stabilité à haute température et les précurseurs utilisés pour la synthèse sont peu couteux. Malheureusement, sa faible conductivité nuit aux performances électrochimiques. Le fait de diminuer la taille des particules ou d’enrober les particules d’une couche de carbone permet d’augmenter la conductivité. Nous avons utilisé une nouvelle méthode appelée « synthèse par voie fondue » pour synthétiser le LiFePO4. Cette synthèse donne des gros cristaux et aucune impureté n’est détectée par analyse Rayon-X. En revanche, la synthèse de LiXFePO4 donne un mélange de LiFePO4 pur et d’impureté à base de lithium ou de fer selon l’excès de fer ou de lithium utilisé. La taille des particules de LiFePO4 est réduite à l’aide d’un broyeur planétaire et plusieurs paramètres de broyage sont étudiés. Une couche de carbone est ensuite déposée sur la surface des particules broyées par un traitement thermique sur le LiFePO4 avec du -lactose. L’influence de plusieurs paramètres comme la température du traitement thermique ou la durée du chauffage sont étudiés. Ces expériences sont réalisées avec un appareil d’analyse thermogravimétrique (ATG) qui donne la quantité de chaleur ainsi que la variation de masse durant le chauffage de l’échantillon. Ce nouveau chauffage pour la couche de carbone donne des échantillons dont les performances électrochimiques sont similaires à celles obtenues précédemment avec la méthode de chauffage pour la couche de carbone utilisant le four tubulaire. / LiFePO4 is a promising cathode material for Lithium-ion batteries. It
provides high thermal stability and is synthesized using low cost materials.
Unfortunately LiFePO4 suffers from a low electrical conductivity, which is harmful
to its electrochemical performance. Decreasing the particle size or coating the
particles with carbon increases the conductivity of the material. We have used a
new synthetic method called molten synthesis to synthesize LiFePO4. The molten
synthesis produces large crystals of LiFePO4 with no impurity detected via X-ray
diffraction analysis. Moreover, the synthesis of LiXFePO4 gives a mixture of pure
LiFePO4 and Li-based impurities or LiFePO4 and Fe-based impurities whenever
there is an excess of lithium or iron used. The particle size of the synthesized
material is reduced via a Planetary Mill and numerous milling parameters were
investigated. A carbon coating was then deposited on the surface of the milled
material by thermally treating LiFePO4 with β-lactose. The influences of several
parameters such as heat treatment temperature and/or heating duration were
studied. These experiments were performed using a thermogravimetric analysis
(TGA), which provides the amount of heat and weight change during the heating
of the sample. This new heating method for carbon coating gave rise to samples
with similar electrochemical performance data as to the previously established
heating method involving a tubular furnace.
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Influence de la taille de départ, de l’état d’agglomération et de la dose de nanoparticules de dioxyde de titane (TiO2) inhalées sur la réponse pulmonaire chez le ratNoël, Alexandra 02 1900 (has links)
En raison de leur petite taille, les nanoparticules (NP) (< 100 nm) peuvent coaguler très rapidement ce qui favorise leur pénétration dans l’organisme sous forme d’agglomérats. L’objectif de cette recherche est d’étudier l’influence de l’état d’agglomération de NP de dioxyde de titane (TiO2) de trois tailles de départ différentes, 5, 10-30 ou 50 nm sur la toxicité pulmonaire chez le rat mâle (F344) exposé à des aérosols de 2, 7 ou 20 mg/m3 pendant 6 heures.
Dans une chambre d’inhalation, six groupes de rats (n = 6 par groupe) ont été exposés par inhalation aiguë nez-seulement à des aérosols ayant une taille primaire de 5 nm, mais produits sous forme faiblement (< 100 nm) ou fortement (> 100 nm) agglomérée à 2, 7 et 20 mg/m3. De façon similaire, quatre autres groupes de rats ont été exposés à 20 mg/m3 à des aérosols ayant une taille primaire de 10-30 et 50 nm. Les différents aérosols ont été générés par nébulisation à partir de suspensions ou par dispersion à sec. Pour chaque concentration massique, un groupe de rats témoins (n = 6 par groupe) a été exposé à de l’air comprimé dans les mêmes conditions. Les animaux ont été sacrifiés 16 heures après la fin de l’exposition et les lavages broncho-alvéolaires ont permis de doser des marqueurs d’effets inflammatoires, cytotoxiques et de stress oxydant. Des coupes histologiques de poumons ont également été analysées.
L’influence de l’état d’agglomération des NP de TiO2 n’a pu être discriminée à 2 mg/m3. Aux concentrations massiques de 7 et 20 mg/m3, nos résultats montrent qu’une réponse inflammatoire aiguë est induite suite à l'exposition aux aérosols fortement agglomérés. En plus de cette réponse, l’exposition aux aérosols faiblement agglomérés à 20 mg/m3 s’est traduite par une augmentation significative de la 8-isoprostane et de la lactate déshydrogénase. À 20 mg/m3, les effets cytotoxiques étaient plus importants suite à l’exposition aux NP de 5 nm faiblement agglomérées. Ces travaux ont montré dans l'ensemble que différents mécanismes de toxicité pulmonaire peuvent être empruntés par les NP de TiO2 en fonction de la taille de départ et de l’état d’agglomération. / Given their small size, nanoparticles (NP) (< 100 nm) can coagulate quickly, which promotes their entry into the body in the form of agglomerates. The objective of this study is to evaluate the influence of the agglomeration state of three different primary particle sizes (5, 10-30 and 50 nm) of titanium dioxide (TiO2) NP on the pulmonary toxicity of male rats (F344) exposed to aerosols at 2, 7 or 20 mg/m3 for 6 hours.
In an inhalation chamber, six groups of rats (n = 6 per group) were acutely exposed by nose-only inhalation to aerosols with a 5-nm primary particle size, produced in the form of small agglomerates (< 100 nm) (SA) or large agglomerates (> 100 nm) (LA) at 2, 7 and 20 mg/m3. Similarly, four other groups of rats were exposed to aerosols at 20 mg/m3 with a primary particle size of 10-30 and 50 nm. The different aerosols were generated by nebulization of suspensions or by dry dispersion. For each mass concentration, one group of control rats (n = 6 per group) was exposed to compressed air under the same conditions. The animals were sacrificed 16 hours after the end of exposure, and analysis of the bronchoalveolar lavage fluids was used to measure markers of inflammatory, cytotoxicity and oxidative stress effects. Lung sections were also analyzed for histopathology.
The influence of the agglomeration state of TiO2 NP (5 nm) could not be determined at 2 mg/m3. For mass concentrations of 7 and 20 mg/m3, our results showed that an acute inflammatory response was induced following exposure to LA aerosols. In addition to this response, exposure to SA aerosols resulted in a significant increase in 8-isoprostane and lactate dehydrogenase. At 20 mg/m3, the cytotoxic effects were greater after exposure to the 5-nm NP in the SA aerosol. This study showed that TiO2 NP use different mechanisms to induce their pulmonary toxicity as a function of their primary particle size and their agglomeration state.
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Polymérisation en émulsion et en miniémulsion. Influence de la combinaison de stabilisants moléculaires et macromoléculaires et suivi en situ par spectroscopie Raman / Emulsion and miniemulsion polymerization. Influence of the combination of molecular and macromolecular stabilizers and in situ monitoring by Raman spectroscopyYoussef, Itab 06 December 2012 (has links)
Cette thèse a pour objet la comparaison des procèdes de polymérisation en émulsion et en miniémulsion. L'influence de la combinaison de stabilisants moléculaires et macromoléculaires sur la cinétique réactionnelle et la distribution de tailles de particules sont les critères pertinents dans notre étude. Un stabilisant polymère, le poly (alcool vinylique-co-acétate de vinyle) (PVA), a été synthétisé avec différents taux d'hydrolyse par saponification directe du polyacétate de vinyle. Le taux d'hydrolyse de ce copolymère a été caractérisé par la Résonance Magnétique Nucléaire du proton (RMN 1H). Puis, nous avons étudié l'influence de la composition d'un mélange stabilisant [copolymères poly (alcool vinylique-co-acétate de vinyle) (PVA)/laurylsulfate de sodium (SDS)] et en particulier le taux d'hydrolyse du PVA. La présence de complexe (PVA/SDS) influence légèrement la cinétique de polymérisation. Par contre la capacité des complexes à stabiliser les particules de latex final dépend du taux d'hydrolyse du PVA, plus ce dernier est faible, plus l'agrégation est importante. Enfin, nous avons suivi en ligne par spectroscopie Raman des polymérisations en émulsion et en miniémulsion du styrène. Une exploitation du spectre a été réalisée et a permis d'attribuer les différents pics aux vibrations de certaines liaisons. La consommation du monomère et l'apparition du polymère a pu être suivi tout au long de la polymérisation / The aim of this work is to compare processes of emulsion and miniemulsion polymerization. The influence of the combination of molecular and macromolecular stabilizers on the reaction kinetics and particle size distribution are relevant factors in our study. A stabilizer polymer, poly (vinyl alcohol-co-vinyl acetate) (PVA), was synthesized with different degrees of hydrolysis by a direct saponification of polyvinyl acetate. The degree of hydrolysis of this copolymer was characterized by Nuclear Magnetic Resonance (1H NMR). Then, we studied the influence of the composition of a mixture stabilizer [poly (vinyl alcohol-co-vinyl acetate) (PVA)/sodium lauryl sulfate (SDS)], and particulary the degree of hydrolysis of PVA. The presence of complex (PVA/SDS) influences slightly the kinetic of polymerization. The ability of the complexes to stabilize the particles of latex depends on the degree of hydrolysis of PVA, the lower it is, the more the aggregation is important. Finally, we followed in situ emulsion and miniemulsion polymerizations of styrene by Raman spectroscopy. The exploitation of the spectrum allowed us to assign the different peaks to vibrations of certain bands. The consumption of the monomer and the appearance of the polymer could be followed throughout the polymerization
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Effect of Bran Particle Size on Gut Microbiota Community Structure and FunctionRiya D Thakkar (6632180) 14 May 2019 (has links)
With the advent of industrialization and food processing techniques the sizes of the cereal bran have been drastically reduced. In my thesis, I have tested the effect, if any, of wheat bran and maize bran particle size, in vitro, on the gut microbiota community structure by 16S rRNA sequencing and their function, by Short chain fatty acids (acetate, propionate, butyrate) production. In turn, we also linked the microbiota and SCFA differences to different chemical composition amongst variously sized fractions of wheat and maize bran.
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A poluição atmosférica por material particulado na mineração a céu aberto. / Atmospheric pollution by particulate matter in the open pit mining.Almeida, Ivo Torres de 20 December 1999 (has links)
Foram abordadas questões relacionadas com a temática da poluição atmosférica provocada pelo material particulado em suspensão. Dois ambientes foram selecionados para estudo: um ambiente de mineração e um ambiente urbano. Com o objetivo de obter uma avaliação preliminar da qualidade do ar nesses ambientes, foi realizado um programa de amostragem para cada área. Dois pontos básicos foram abordados nessa avaliação: a determinação da concentração de partículas totais em suspensão e a caracterização química e física do material particulado. A determinação das concentrações de partículas totais em suspensão foi obtida através do uso de amostradores de grande volume (Hi-vols). O método de referência utilizado foi o método do amostrador de grande volume proposto pela ABNT através da norma NBR 9547: 97. A caracterização física envolveu a determinação da distribuição granulométrica do material particulado em suspensão enquanto que a caracterização química compreendeu a determinação da sua composição. As técnicas analíticas utilizadas na caracterização do material particulado, foram a espectrometria de Fluorescência de Raios-X (XRF) para a caracterização química, e o Espalhamento de Luz Laser de Baixo Angulo (LALLS) para a caracterização física. Com relação às concentrações de partículas totais em suspensão, os resultados indicaram que as áreas de mineração apresentaram valores superiores aos encontrados na área urbana, inclusive com ultrapassagens dos padrões legais, fato este que não ocorreu na área urbana estudada. Para a distribuição granulométrica do material particulado, os resultados demonstraram que as frações mais finas do particulado apresentaram-se em maiores quantidades nas áreas de mineração, enquanto que as frações mais grosseiras apresentaram-se em maior quantidade na área urbana. Quanto à composição química do material particulado em suspensão, podemos concluir que para as áreas de mineração, esta foi muito semelhante à da rocha lavrada. / Atmospheric pollution aspects were analyzed. Two types of ambients were selected for study: a mining ambient and an urban ambient. To obtain a preliminary evaluation of the quality of the air in these ambients a sampling program was accomplished for each area. Two basic points were studied: the concentration of the total suspended particulates and the chemical and physical characterization of the particulate matter. The concentrations of total suspended particulates were obtained through the use of high volume samplers (Hi-vols). The reference method used was the high volume sampler method, proposed by ABNT through the norm NBR 9547: 97. The physical characterization involved the determination of the size distribution of the suspended particulate matter while the chemical characterization involved the determination of its composition. The analytic techniques used for the characterization of the particulate matter were the X-Ray Fluorescence (XRF) for the chemical characterization, and the Low Angle Laser Light Scattering (LALLS) for the physical characterization. Concentration levels for total suspended particulates showed that the mining areas presented higher values than those for urban area. Legal standards were exceeded in the mining area, fact that did not occur in the urban area. Size distributions of the particulate matter demonstrated that the finest fractions were found in larger amounts in the mining areas, while the coarses fractions were present in larger amounts in the urban area. The chemical compositions of the suspended particulate matter in the mining areas were very similar to the compositions of the rocks been mined.
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Enzimas fibrolíticas e emurchecimento no controle de perdas da ensilagem e na digestão de nutrientes em bovinos alimentados com rações contendo silagem de capim Tanzânia. / Fibrolytic enzymes and wilting to control ensiling losses and nutrient digestion in bovine fed with Tanzania grass silage based rations.Loures, Daniele Rebouças Santana 29 April 2004 (has links)
Este trabalho teve por objetivo avaliar o efeito de enzimas fibrolíticas na degradação da parede celular do volumoso, quando aplicadas antes da ensilagem e no momento da alimentação do animal. No experimento I analisou-se o efeito do emurchecimento, da redução do tamanho de partículas e da adição de enzimas fibrolíticas (associadas ou não ao inoculante bacteriano Lactobacillus plantarum) na fermentação e nas perdas do processo de ensilagem de capim Tanzânia (Panicum maximum, Jacq. cv. Tanzânia). A forragem foi cortada aos 45 dias de crescimento vegetativo e armazenada em silos experimentais (50 L) durante 136 dias. Durante o período de armazenamento o efluente foi coletado e quantificado no 1o, 2o, 7o, 14o, 21o, 60o, 90o e 136o dias. A redução do tamanho de partícula não influenciou as perdas totais, embora o tamanho menor tenha contribuído para garantir maior estabilidade aeróbia da silagem. A taxa de recuperação e as perdas de MS por efluente e gases foram de 72, 5 e 23% nas silagens não-emurchecidas e de 80, 0 e 21% nas silagens emurchecidas, respectivamente. A adição de enzimas fibrolíticas associadas ou não ao inoculante bacteriano promoveu redução da fração fibrosa (FDN, FDA, celulose, hemicelulose), sendo esta redução mais acentuada nas silagens emurchecidas. Contudo, não houve aumento da digestibilidade in vitro da MS com adição de enzimas fibrolíticas. Foram observados os valores médios de DBO (11.289 mg L -1), DQO (36.279 mg L -1) e DQO/DBO (3,35) no efluente das silagens contendo umidade original; o maior período de armazenamento aumentou significativamente o potencial poluidor do efluente. O experimento II teve por objetivo avaliar o efeito do conteúdo de matéria seca da forragem e o uso de enzimas fibrolíticas aplicadas durante a ensilagem de capim Tanzânia ou após a abertura do silo. Os tratamentos foram confeccionados da seguinte forma: A - forragem emurchecida sem aplicação de enzimas; B - não-emurchecida sem aplicação de enzimas; C - emurchecida com enzimas (2 L t -1 de massa verde); D - não-emurchecida com enzimas; e E - não-emurchecida com enzimas (10 L t -1 de massa verde), após a abertura do silo. Cinco novilhos da raça Nelore foram distribuídos ao acaso em delineamento do tipo Quadrado Latino 5 x 5. Os parâmetros de cinética de passagem de sólidos (2,23% hora-1) e de líquidos (4,83% hora-1) foram similares para os tratamentos avaliados. O comportamento ingestivo dos animais não foi alterado com a elevação da concentração de MS da silagem, sendo observados os seguintes tempos (minutos dia-1) e taxas (min kg MSI-1) de ingestão de MS (247 e 24), de ruminação (426 e 43) e de mastigação (673 e 67), respectivamente. As médias das concentrações totais dos ácidos graxos voláteis (109,62 mM) e de nitrogênio amoniacal (5,6 mg dL-1), do fluido ruminal, não foram alteradas pelos tratamentos aplicados. Diante dessas observações, pode-se concluir que o emurchecimento da forragem e o uso de aditivo enzimático não resultaram em alterações significativas no comportamento ingestivo, nos parâmetros ruminais e na digestibilidade de nutrientes em animais. / The present trial aimed to evaluate the effect of fibrolytic enzymes on forage cell wall degradation, when applied either during the ensiling process or just before the animal feeding. The experiment I analyzed the effects of wilting (wet vs wilted), particle size reduction (small vs large) and the addition of fibrolytic enzymes (alone vs combined with Lactobacillus plantarum) on the fermentation and ensiling losses of Tanzania grass (Panicum maximum, Jacq. cv. Tanzania). Forage was harvested and cut at 45-day vegetative re-growth period and stored in experimental plastic silos (50 L) during 136 days. During the storage period, the effluent flow was collected and measured at days 1, 2, 7, 14, 21, 60, 90 and 136. Total silage losses were not affected by particle size reduction, even though the smallest particle size promoted better aerobic stability of the silage. The rate of silage DM recovery, effluent and gases losses were 72, 5 e 23 % for wet and 80, 0 e 21% for wilted silages, respectively. The addition of fibrolytic enzymes exclusively or combined with Lactobacillus plantarum led to decreased concentrations of NDF, ADF, cellulose and hemicellulose mainly on wilted silages, however, no benefit was observed in the in vitro DM digestibility. Mean values for BOD (11.289 mg L -1), COD (36.279 mg L -1), and the ratio COD/BOD (3.35) were observed on the effluent of wet silages, which increased the potential of environmental pollution with the longer silage storage period. The experiment II aimed to study the effects of forage wilting or fibrolytic enzymes addition to the Tanzania grass silages. Treatments consisted of: A - wilted forage without enzymes; B - fresh forage without enzymes; C - wilted forage with enzymes at ensiling (2 L t-1 wet forage); D - fresh forage with enzymes at ensiling; E - enzymes applied onto silage (10 L t-1 wet silage) 30 minutes before feeding (direct-fed). Five ruminally cannulated Nellore beef steers were randomly assigned to a 5 x 5 Latin square design. The ruminal passage rate of solid (2.23 % hour -1) and liquid (4.83 % hour -1) phases were similar for all treatments. The animal ingestive behavior measured as total time (minutes day-1) and rate (minutes DM kg-1) was not changed across silages DM concentration, averaging DM eating (247; 24), DM ruminating (426; 43) and DM chewing (673; 67), respectively. The molar concentration (109.62 mM) of total volatile fatty acids (VFA) and ammonia-N (5.6 mg dL-1) observed in ruminal fluid were similar across silages diets. According to the results it may be concluded that wilting Tanzania grass or the application of fibrolytic enzymes did not improve significantly either the animal ingestive behavior, ruminal parameters or the nutrient digestibilty.
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Avalanching on dunes and its effects : size statistics, stratification, & seismic surveysArran, Matthew Iain January 2018 (has links)
Geophysical research has long been interdisciplinary, with many phenomena on the Earth's surface involving multiple, linked processes that are best understood using a combination of techniques. This is particularly true in the case of grain flows on sand dunes, in which the sedimentary stratification with which geologists are concerned arises from the granular processes investigated by physicists and engineers, and the water permeation that interests hydrologists and soil scientists determines the seismic velocities of concern to exploration geophysicists. In this dissertation, I describe four projects conducted for the degree of Doctor of Philosophy, using a combination of laboratory experimentation, fieldwork, numerical simulation, and mathematical modelling to link avalanching on dunes to its effects on stratification, on the permeation of water, and on seismic surveys. Firstly, I describe experiments on erodible, unbounded, grain piles in a channel, slowly supplied with additional grains, and I demonstrate that the behaviour of the consequent, discrete avalanches alternates between two regimes, typified by their size statistics. Reconciling the `self-organised criticality' that several authors have predicted for such a system with the hysteretic behaviour that others have observed, the system exhibits quasi-periodic, system-spanning avalanches in one regime, while in the other avalanches pass at irregular intervals and have a power-law size distribution. Secondly, I link this power-law size distribution to the strata emplaced by avalanches on bounded grain piles. A low inflow rate of grains into an experimental channel develops a pile, composed of strata in which blue-dyed, coarser grains overlie finer grains. Associating stopped avalanche fronts with the `trapped kinks' described by previous authors, I show that, in sufficiently large grain piles, mean stratum width increases linearly with distance downslope. This implies the possibility of interpreting paleodune height from the strata of aeolian sandstones, and makes predictions for the structure of avalanche-associated strata within active dunes. Thirdly, I discuss investigations of these strata within active, Qatari barchan dunes, using dye-infiltration to image strata in the field and extracting samples across individual strata with sub-centimetre resolution. Downslope increases in mean stratum width are evident, while measurements of particle size distributions demonstrate preferential permeation of water along substrata composed of finer particles, explaining the strata-associated, localised regions of high water content discovered by other work on the same dunes. Finally, I consider the effect of these within-dune variations in water content on seismic surveys for oil and gas. Having used high performance computing to simulate elastic wave propagation in the vicinity of an isolated, barchan sand dune, I demonstrate that such a dune acts as a resonator, absorbing energy from Rayleigh waves and reemitting it over an extensive period of time. I derive and validate a mathematical framework that uses bulk properties of the dune to predict quantitative properties of the emitted waves, and I demonstrate the importance of internal variations in seismic velocity, resulting from variations in water content.
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Synthesis of Aluminum-Titanium Carbide Nanocomposites by the Rotating Impeller Gas-Liquid In-situ MethodAnza, Inigo 06 September 2016 (has links)
"The next generation of aluminum alloys will have to operate at temperatures approaching 300°C. Traditional aluminum alloys cannot perform at these temperatures, but aluminum alloys reinforced with fine ceramic particles can. The objective of this research is to develop a process to synthesize Al-TiC composites by the Rotating Impeller Gas-Liquid In-situ method. This method relies on injecting methane into molten aluminum that has been pre-alloyed with titanium. The gas is introduced by means of a rotating impeller into the molten alloy, and under the correct conditions of temperature, gas flow, and rotation speed, it reacts preferentially with titanium to form titanium carbide particles. The design of the apparatus, the multi-physics phenomena underlying the mechanism responsible for particle formation and size control, and the operation window for the process are first elucidated. Then a parametric study that leads to the synthesis of aluminum reinforced with TiC microparticles and nanoparticles is described. Finally, potential technical obstacles that may stand in the way of commercializing the process are discussed and ways to overcome them are proposed. "
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Fizičke karakteristike zemljišta i distribucija teških metala na gradskom području Novog Sada / Physical properties and the distribution of heavy metals in soils of the urban area of Novi SadMihailović Aleksandra 25 August 2015 (has links)
<p>Uzorci zemljišta iz povšinskog sloja dubine 0 - 10 cm<br />prikupljeni su sa 121 lokacije na gradskom području Novog<br />Sada. Ispitivano područje obuhvatilo je površinu (4 x 5)km<sup>2</sup>,<br />koja je podeljena na mrežna polja veličine (400 x 400) m<sup>2 </sup>i u <br />svakom polju uzet je po jedan uzorak. Za 121 uzorak<br />gradskog zemljišta Novog Sada ispitana su fizičko-hemijska<br />svojstva zemljišta, ukupni i pristupačni sadržaj metala (As,<br />Co, Cr, Cu, Mn, Ni, Pb, Zn) i njihova prostorna raspodela.<br />Konturne mape prostorne raspodele metala u zemljištu<br />dobijene su korišćenjem interpolacijske metode običnog<br />kriginga. Za pojedine uzorke izvršeno je razdvajanje čestica<br />po veličinama frakcionisanjem u vodi pomoću sita različitih<br />veličina i identifikovani su minerali prisutni u frakciji prah +<br />glina. Aktivnosti radionuklida „unsupported”<sup> 210</sup>Pb i <sup>137</sup>Cs<br />određene su za jedan deo uzoraka zemljišta u Novom Sadu i<br />za uzorke zemljišta pored fabrike akumulatora u Somboru.<br />Ispitana je i vertikalna distribucija stabilnog i radioaktivnog<br />Pb u zemljištu.</p><p>Na 14 lokacija u Novom Sadu prikupljeno je 35 uzoraka<br />snega direktno sa asfaltnih puteva i sa zemljanih površina u<br />okolini puteva i na pešačkim ostrvima. Raspodela čestica po<br />veličinama i ukupne koncentracije metala (Al, Ca, Cu, Fe, K,<br />Na, Mn, Ni, Pb, Zn) određene su analizom filtriranih uzoraka,<br />a za 4 uzorka ispitana je morfologija čestica i urađena<br />semikvantitativna analiza čestica u suvoj materiji.</p><p>Prilikom obrade rezultata merenja primenjene su metode<br />deskriptivne statistike i multivarijacione statističke analize u<br />cilju identifikacije izvora zagađenja i određivanja povezanosti<br />između samih metala i drugih parametara.</p> / <p>A total of 121 surface soil samples were collected across the central part of Novi Sad covering a surface area (4 km x 5 km). The physicochemical properties, pseudo total and available metal concentrations (As, Co, Cr, Cu, Mn, Ni, Pb, and Zn) were determined. Contour maps of spatial distribution of the investigated metals were obtained using ordinary kriging interpolation method. Separation of different particle <br />size fractions by wet sieving and identification of minerals in the clay and silt fraction for some soil samples were performed. Specific activities of radionuclides “unsupported” <sup>210</sup>Pb and <sup>137</sup>Cs were measured in forty soil samples collected in urban area of Novi Sad and industrial area of Sombor (near a battery manufacturer). Vertical distribution of stable and radioactive Pb for two samples from the industrial soil was examined.</p><p>Thirty five snow samples were collected at fourteen locations near crossroads in Novi Sad. The samples were taken directly from the road surface and from the ground surface in the vicinity of roads and on pedestrian islands. Particle size distribution and total concentration of the metals (Al, Ca, Cu, Fe, K, Na, Mn, Ni, Pb, Zn) were determined for filtered samples. Semi-quantitative analysis of the particles was conducted and morphology of the particles was examined for dry matter of four snow samples. </p><p>Methods of descriptive and multivariate statistics and geostatistics were carried out for the analysis and interpretation of the data.</p>
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