Small quantities of reduced sulphur compounds (RSCs) emitted from Kraft pulp mills can affect air quality due to low odour thresholds. Chromatographic methods were developed for individual RSCs at ppt to ppb concentrations. Analyses of ambient air samples showed that while H2S, CH3SH, DMS and DMDS were linked to the pulp mill, the majority of COS and CS2 was due to other sources unrelated to the mill. The fluxes of individual RSCs from kraft wastewater clarifiers were quantified for the first time. DMDS and DMS were the major RSCs emitted from the primary and secondary clarifiers, respectively. RSC fluxes were one to three orders of magnitude higher at the primary clarifier than at the secondary one. Clarifier emissions were, however, insignificant compared to point sources in the mill. Statistically significant correlations were found between the DMS emission and BOD, COD, as well as TSS in the secondary treatment system.

Der Folsäureantagonist Methotrexat (MTX) wird zur Behandlung onkologischer und rheumatoider Erkrankungen eingesetzt. Die Aufnahme des Methotrexats in die Zielzelle ist dabei Vorraussetzung für die Bindung an seine intrazellulären Zielstrukturen und erfolgt über verschiedene Transportsysteme. In diesem Zusammenhang ist bei entsprechenden Plasma-konzentrationen von MTX der Reduced Folate Carrier (RFC1) von besonderer Bedeutung. 1994 konnte erstmals die cDNA dieses Transporters aus Maus- und Hamstergewebe isoliert werden. Die cDNA für einen mit dem RFC1 identischen hepatozellulären MTX-Transporter der Ratte wurde 2000 kloniert. Vorhergehende Gen-Expressionsstudien zeigten, dass die RFC1-mRNA ubiquitär gebildet wird. Die Proteinexpression wurde jedoch bisher nur in ausgewählten Geweben der Maus untersucht. Systematische Arbeiten, in denen in vergleichender Weise sowohl die RFC1 Gen- als auch die Proteinexpression in allen Geweben mit einer möglichen Relevanz für die Folat- und Antifolataufnahme, Speicherung und Eliminierung untersucht werden, fehlten bisher. Insbesondere die Expression des RFC1-Proteins der Ratte (rRFC1) mittels immunologischer Verfahren ist bisher nicht beschrieben worden. Ziel dieser Arbeit war es daher, die Gen- und Proteinexpression des rRFC1 in ausgewählten Geweben der Ratte darzustellen. Dieses schließt die Generierung spezifischer Antiseren gegen den rRFC1 als ersten Schritt mit ein. Es wurden geeignete antigene Aminosäuresequenzen des rRFC1 bestimmt und die entsprechenden cDNA Sequenzen wurden amplifiziert und in einen geeigneten Expressionsvektor kloniert. Rekombinante rRFC1 Fusionsproteine konnten mittels E. coli Zellen hergestellt und anschließend aufgereinigt werden. Nachfolgend wurden entweder die rRFC1 Fusionsproteine oder die rRFC1 spezifischen Peptide, welche von dem Affinitätspeptid separiert worden waren, für die Immunisierung von Kaninchen verwendet Drei Antiseren mit ausreichender Reaktivität und Spezifität konnten gewonnen und mittels Affinitätschromatographie aufgereinigt werden. Die erhaltenen Antiseren sind gegen die intrazellulären N- und C-terminalen Regionen (ID1, ID7) bzw. gegen die erste extrazelluläre Schleife (OD1) gerichtet. In Western-Blot Studien konnte mittels dieser Antiseren für den rRFC1, der in transfizierten Nierenepithelzellen (MDCK-rRFC-HA) stabil exprimiert wurde, ein Molekulargewicht von 71 kD für die glykosylierte Form und von 53 kD für die unglykosylierte Form ermittelt werden. Weiter konnte belegt werden, dass das Protein in MDCK-rRFC1-HA Zellen überwiegend in der glycosylierten Form vorliegt. Mittels RT-PCR Analysen wurde die Genexpression des rRFC1 in allen untersuchten Geweben nachgewiesen. Besonders hohe mRNA-Gehalte waren in Thymus, Niere und Milz vorhanden, während in Herz- und Muskelgewebe sowie in Leukozyten nur ein Signal nahe der Nachweisgrenze detektierbar war. Durch immunhistologische Untersuchungen konnten die rRFC1 Proteinexpression und beträchtliche Unterschiede in der Signalintensität bestätigt werden. Zusätzlich konnten neue Informationen über die unterschiedliche subzelluläre Lokalisation gewonnen werden: so konnte eine starke Expression des Transporters in der apikalen Membran von Dünn- und Dickdarmmukosa dargestellt werden, während die ebenfalls starke Färbung in der Niere auf den Bereich der basolateralen Membran der Tubuli beschränkt war. In der Leber war eine Expression mittlerer Intensität im Bereich der Lebertrias erkennbar. Während in der Milz nur in der roten Pulpa das RFC1-Protein detektiert wurde, konnten im Thymus sowohl in der Rinde als auch im Mark positive Zellen nachgewiesen werden. Im Hoden konnte der Transporter in den Sertoli-Zellen dargestellt werden. Eine starke Expression des Transporters wurde im Gehirn im Bereich der apikalen Membran der Ependymzellen des Plexus choroideus nachgewiesen. In der Skelettmuskulatur und im Herzgewebe beschränkte sich die Expression des rRFC1 auf das Perimysium des Muskelgewebes und auf kleinere Gefäße des Muskel- und Herzgewebes. In dieser Arbeit konnte somit gezeigt werden, dass der RFC1 der Ratte ubiquitär exprimiert wird, wobei die Expressionsstärke jedoch stark variiert. Die beobachtete Gewebslokalisation des RFC1 belegt sowohl dessen zentrale Rolle in der Folathomöostase als auch in der MTX vermittelten Organtoxizität und Pharmakokinetik, insbesondere bei der intestinalen Resorption sowie der hepatischen und renalen Exkretion.

No description available.

Nanomaterials are currently attracting billions of dollars in research funding and are entering such diverse fields as the computing, communications, life science and energy sectors. The growing popularity of nanomaterials demands a comprehensive understanding of the means by which such materials can be produced including the effects of physical and chemical factors. One method of forming inorganic nanomaterials is the sol-gel process; a low temperature process combining the benefits of glass and plastics technology. Whilst the research community has ascertained that gravity is important and appears to affect the sol-gel process, no coherent picture of the role of gravity on the sol-gel process has been proposed. The flexibility of the sol-gel process, and the promise it holds for creating products as diverse as hydrogen fuel cell membranes through to protective coatings for space vehicles, make it an important area of study. This thesis addressed a fundamental gap in the scientific knowledge concerned with the sol-gel process: how and why does gravity affect the sol-gel process? The nanomaterial chosen for study was a xerogel, a dense compound with a high surface area which finds applications in high temperature ceramics, energy saving coatings, molecular filtration and thin film sensors. The xerogel was produced from an acid catalysed sol. 2ml samples of the sol were subjected to reduced, normal and high gravity levels, and the resultant xerogels were characterised through liquid and solid state NMR and nitrogen adsorption/desorption techniques. Viscosity and pH measurements were also recorded. Reduced gravity conditions were provided by NASA’s KC-135 aircraft which is capable of creating a 25 second window of 1x10−2 gravities. A centrifuge was utilised to simulate increased gravity environments and xerogels were formed between 2 and 70 gravities. Analysis of the results led to two major contributions to this field of scientific endeavour. It was concluded that (1) gravity affected the reaction pathways of the sol-gel process and (2) gravity directly altered the molecular structure of xerogels The second contribution was determined through the NMR studies, where it was shown that a reduction in gravity resulted in a molecular structure composed of extended branches of cyclic compounds. Due to a decrease in convection in reduced gravity the molecular structure of the sample was dominated by cyclisation. In terrestrial and high gravity the molecular structure grew through both bimolecularisation and cyclisation reactions. Thus the gravity level also determined the reaction pathway available within the sol by creating a more or less convective environment. This created a structure composed of cyclics (rings) and chains. As gelation and drying of the sol occurred there was a loss in Q4 group amount. Chains, having a higher energy configuration than rings, underwent repolymerisation. Short chains formed which reacted end-to-end to form small, stable rings. The rings packed together more closely within the liquid sol and delayed the formation of a spanning cluster. The greater the gravity level, the greater the extent of bimolecularisation reactions contributing to chain formation, in turn allowing a greater degree of repolymerisation of the molecular structure. Thus gel times increased as the gravity level increased. Again gravity directly affected the reaction pathway of the sol-gel process. In reduced gravity the sol gelled very quickly due to the formation of a cyclic structure which was not capable of repolymerisation. The final contribution of this thesis was the proposal of a mechanistic model. The model depicted the ffect of gravity on the formation of the molecular structure of a xerogel.

Thesis (M.S.)--Rochester Institute of Technology, 1994. / Typescript. Includes bibliographical references (leaf 170).

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: microgravity; condensation; ultrasound. Includes bibliographical references (p. 138).

Thesis (M.S.)--Michigan State University. Dept. of Mechanical Engineering, 2007. / Title from PDF t.p. (viewed on Aug. 11, 2009) Includes bibliographical references (p. 85). Also issued in print.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: crown; splash; spreading; oscillatory; droplets; microgravity; viscosity; map; stability; solid surface; surface tension; gravity. Includes bibliographical references (p. 111-113).

abstract: This thesis focuses on the continued extension, validation, and application of combined thermal-structural reduced order models for nonlinear geometric problems. The first part of the thesis focuses on the determination of the temperature distribution and structural response induced by an oscillating flux on the top surface of a flat panel. This flux is introduced here as a simplified representation of the thermal effects of an oscillating shock on a panel of a supersonic/hypersonic vehicle. Accordingly, a random acoustic excitation is also considered to act on the panel and the level of the thermo-acoustic excitation is assumed to be large enough to induce a nonlinear geometric response of the panel. Both temperature distribution and structural response are determined using recently proposed reduced order models and a complete one way, thermal-structural, coupling is enforced. A steady-state analysis of the thermal problem is first carried out that is then utilized in the structural reduced order model governing equations with and without the acoustic excitation. A detailed validation of the reduced order models is carried out by comparison with a few full finite element (Nastran) computations. The computational expedience of the reduced order models allows a detailed parametric study of the response as a function of the frequency of the oscillating flux. The nature of the corresponding structural ROM equations is seen to be of a Mathieu-type with Duffing nonlinearity (originating from the nonlinear geometric effects) with external harmonic excitation (associated with the thermal moments terms on the panel). A dominant resonance is observed and explained. The second part of the thesis is focused on extending the formulation of the combined thermal-structural reduced order modeling method to include temperature dependent structural properties, more specifically of the elasticity tensor and the coefficient of thermal expansion. These properties were assumed to vary linearly with local temperature and it was found that the linear stiffness coefficients and the "thermal moment" terms then are cubic functions of the temperature generalized coordinates while the quadratic and cubic stiffness coefficients were only linear functions of these coordinates. A first validation of this reduced order modeling strategy was successfully carried out. / Dissertation/Thesis / M.S. Aerospace Engineering 2011

Neste trabalho apresenta-se uma modelagem e a simulação de chamas difusivas turbulentas de etanol. A pesquisa trata da simulação da mistura molecular envolvendo reações químicas e combustão. Como os modelos de cinética química detalhada podem tornar-se computacionalmente proibitivos, por possuírem inúmeras reações e várias espécies, modelos cinéticos reduzidos são adotados. O mecanismo de oxidação do etanol utilizado possui 372 reações elementares e 56 espécies. Para diminuir a rigidez do sistema de equações rea- tivas resultantes, desenvolveu-se um mecanismo reduzido através do Método de Redução Sistemático, que usa as hipóteses de equilíbrio parcial e de regime permanente. A técnica Reaction Difusion Manifolds (REDIM), que aplica o conceito de variedade invariante, também foi implementada. A formulação Euleriana é utilizada para resolver as equações governantes da fase gasosa, que incluem as equações de Navier-Stokes, fração de mistura, fração mássica das espécies e temperatura. O efeito das gotas, fase líquida, é considerado pela introdução de termos fonte apropriados nas equações da fase gasosa. A Simulação em Grandes Escalas é utilizada para representar o fluxo turbulento com o modelo submalha de Smagorinsky para modelar a viscosidade turbulenta. Na simulação numérica adota-se o método de diferenças finitas com um sistema não oscilatório do tipo Total Variation Diminishing (TVD). O domínio é um queimador tridimensional com malha não uniforme para garantir a eficiência e precisão nos resultados em regiões onde o refinamento faz-se necessário. Para validar o modelo, além dos resultados numéricos para chamas difusivas de etanol, também realiza-se testes numéricos para chamas difusivas de metano e metanol, e os resultados obtidos comparam favoravelmente com dados encontrados na literatura. / This work presents the modeling and simulation of turbulent diffusion flames of etha- nol. The study addresses the simulation of the molecular mixing, chemical reactions and combustion. Since detailed chemical kinetics models may be computationally prohibitive, reduced kinetic models are adopted. The ethanol oxidation mechanism consists of 372 elementary reactions and 56 species. To decrease the stiffness of the reactive system of equations, a reduced mechanism is developed using the Systematic Reduction Method, based on the partial equilibrium and steady-state approximations. The Reaction Diffusion Manifolds (REDIM) technique, which applies the concept of invariant manifolds to treat the influence of the transport processes on the reduced model, is also employed. The Eule- rian formulation is used to solve the governing equations of the gas phase, which includes the Navier-Stokes, mixture fraction, species mass fraction and temperature equations. The effect of the drops, the liquid phase, is considered by introducing appropriate source terms in the equations of the gas phase. Large-Eddy Simulation is used to represent the turbulent flow with the Smagorinsky model for the turbulent viscosity. The numerical simulations are carried out using the finite difference method with a non oscillatory Total Variation Diminishing (TVD) scheme. The burner is a three-dimensional domain with nonuniform mesh to ensure efficiency and accuracy in regions where mesh refinement is necessary. To validate the model, besides the numerical results for diffusive flames of ethanol, numerical tests for methane and methanol diffusive flames are also carried out and the results compare favourably with data in the literature.