Intrauterine exposure to diesel exhaust diminishes adult ovarian reserve

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação da construção e operação de técnicas compensatórias de drenagem urbana: o transporte de finos, a capacidade de infiltração, a taxa de infiltração real do solo e a permeabilidade da manta geotêxtil

This work aimed to evaluate some aspects of construction and operation of full-scale best management practices and their effects on infiltration loading rate. Two systems were studied: i) filter-swale-trench (FST) and ii) infiltration well (IW). In these units, field essays and full-scale measurements were made in order to assess the soil permeability. Further, the fine particles transportation and the geotextile blanket permeability were determined before and after operation. The results pointed out that there were soil transportation to inside the FST and IW systems, despite of the installed protections, and that these material were responsible for diminishing the geotextile (reduction from 30 to 90% for FST and 40 to 70% for IW) and the full-scale infiltration loading rates (varying from 4,7 x 10-6 to 10-5 m.s-1).

Study of combustion of different biomass and its atmospheric emissions

One of the energy alternatives that provide utility, flexibility, cleanliness and economy is biomass, such as forest waste (wood) and agricultural (sugarcane bagasse, rice husks, coffee pods, etc.). However, with its increasing supply and use grows also the concern of industries to invest in monitoring and control of emissions into the atmosphere, because during biomass burning are emitted as exhaust gases, fine particles known as particulates, which greatly contribute to the triggering of serious health problems to humans, in addition to the environmental damage. With that, this work aimed to conduct a monitoring of particulate and gaseous pollutants emissions to the atmosphere from the burning of various types of biomass used by industries. The equipment used for sampling were the optical monitor DataRAM 4 and the Unigas3000 + gas sampler. The results showed that biomass coffee pods presented the greatest concentration of particulates (485119 μg m-3) with particle diameters between 0.0602 μm and 0.3502 μm, i.e. the most ultrafine particles, harmful to human health and the environment. The largest emissions of CO and NOx were observed, respectively, for the coffee pods (3500 ppm) and for the rice husk (48 ppm). As for the superior calorific value (PCS), the best of fuel, with higher PCS, was the Eucalyptus grandis.

Use of levoglucosan, potassium, and water-soluble organic carbon to characterize the origins of biomass-burning aerosols

Three chemical species related to biomass burning, levoglucosan, potassium and water-soluble organic carbon (WSOC), were measured in aerosol samples collected in a rural area on the outskirts of the municipality of Ourinhos (Sao Paulo State, Brazil). This region is representative of the rural interior of the State, where the economy is based on agro-industrial production, and the most important crop is sugar cane. The manual harvesting process requires that the cane be first burned to remove excess foliage, leading to large emissions of particulate materials to the atmosphere. Most of the levoglucosan (68-89%) was present in small particles (<1.5 mu m), and its concentration in total aerosol ranged from 25 to 1186 ng m(-3). The highest values were found at night, when most of the biomass burning occurs. In contrast, WSOC showed no diurnal pattern, with an average concentration of 5.38 +/- 2.97 mu g m(-3) (n = 27). A significant linear correlation between levoglucosan and WSOC (r = 0.54; n = 26; p < 0.0001) confirmed that biomass burning was in fact an important source of WSOC in the study region. A moderate (but significant) linear correlation between levoglucosan and potassium concentrations (r = 0.62; n = 40; p < 0.0001) was indicative of the influence of other sources of potassium in the study region, such as soil resuspension and fertilizers. When only the fine particles (<1.5 pm; typical of biomass burning) were considered, the linear coefficient increased to 0.91 (n = 9). In this case, the average levoglucosan/K+ ratio was 0.24, which may be typical of biomass burning in the study region. This ratio is about 5 times lower than that previously found for Amazon aerosol collected during the day, when flaming combustion prevails. This suggests that the levoglucosan/K+ ratio may be especially helpful for characterization of the type of vegetation burned (such as crops or forest), when biomass-burning is the dominant source of potassium. The relatively high concentrations of WSOC (and inorganic ions) suggest an important influence on the formation of cloud condensation nuclei, which is likely to affect cloud formation and precipitation patterns. (C) 2012 Elsevier Ltd. All rights reserved.

Shape fabric development during progressive deformation

Zusammenfassung:Das Ziel dieser Arbeit ist ein besseres Verständnis von der Art und Weise wie sich Formregelungsgefüge entwicklen. Auf dieser Basis wird der Nutzen von Formregelungsgefügen für die Geologie evaluiert. Untersuchungsmethoden sind Geländearbeit und -auswertung, numerische Simulationen und Analogexperimente. Untersuchungen an Formregelungsgefügen in Gesteinen zeigen, daß ein Formregelungsgefüge nur zu einem begrenzten Grad als Anzeiger für die Stärke der Verformung benutzt werden kann. Der angenommene Grund hierfür ist der Einfluß des Verhältnisses von ursprünglicher zu rekristallisierter Korngröße auf die Gefügeentwicklung und von der Art und Weise wie dynamische Rekristallisation ein Gefüge verändert. Um diese Beobachtung zu evaluieren, wurden verschiedene numerische Simulationen von dynamischer Rekristallisation durchgeführt. Ein neuer Deformationsapparat, mit dem generelle Fließregime modelliert werden können, wurde entwickelt. Die rheologischen Eigenschaften von Materialien, die für solche Experimente benutzt werden, wurden untersucht und diskutiert. Ergebnisse von Analogexperimenten zeigen, daß die Intensität eines Formregelungsgefüges positiv mit der Abnahme der 'kinematic vorticity number' und einem nicht-Newtonianischen, 'power law' Verhalten des Materixmaterials korreliert ist. Experimente, in denen die Formveränderung von viskosen Einschlüssen während der progressiven Verformung modelliert werden, zeigen, daß verschiedene Viskositätskontraste zwischen Matrix- und Einschlußmaterial in charakteristische Formgefüge resultieren.

Biomass Gasification - Process analysis and dimensioning aspects for downdraft units and gas cleaning lines

In such territories where food production is mostly scattered in several small / medium size or even domestic farms, a lot of heterogeneous residues are produced yearly, since farmers usually carry out different activities in their properties. The amount and composition of farm residues, therefore, widely change during year, according to the single production process periodically achieved. Coupling high efficiency micro-cogeneration energy units with easy handling biomass conversion equipments, suitable to treat different materials, would provide many important advantages to the farmers and to the community as well, so that the increase in feedstock flexibility of gasification units is nowadays seen as a further paramount step towards their wide spreading in rural areas and as a real necessity for their utilization at small scale. Two main research topics were thought to be of main concern at this purpose, and they were therefore discussed in this work: the investigation of fuels properties impact on gasification process development and the technical feasibility of small scale gasification units integration with cogeneration systems. According to these two main aspects, the present work was thus divided in two main parts. The first one is focused on the biomass gasification process, that was investigated in its theoretical aspects and then analytically modelled in order to simulate thermo-chemical conversion of different biomass fuels, such as wood (park waste wood and softwood), wheat straw, sewage sludge and refuse derived fuels. The main idea is to correlate the results of reactor design procedures with the physical properties of biomasses and the corresponding working conditions of gasifiers (temperature profile, above all), in order to point out the main differences which prevent the use of the same conversion unit for different materials. At this scope, a gasification kinetic free model was initially developed in Excel sheets, considering different values of air to biomass ratio and the downdraft gasification technology as particular examined application. The differences in syngas production and working conditions (process temperatures, above all) among the considered fuels were tried to be connected to some biomass properties, such elementary composition, ash and water contents. The novelty of this analytical approach was the use of kinetic constants ratio in order to determine oxygen distribution among the different oxidation reactions (regarding volatile matter only) while equilibrium of water gas shift reaction was considered in gasification zone, by which the energy and mass balances involved in the process algorithm were linked together, as well. Moreover, the main advantage of this analytical tool is the easiness by which the input data corresponding to the particular biomass materials can be inserted into the model, so that a rapid evaluation on their own thermo-chemical conversion properties is possible to be obtained, mainly based on their chemical composition A good conformity of the model results with the other literature and experimental data was detected for almost all the considered materials (except for refuse derived fuels, because of their unfitting chemical composition with the model assumptions). Successively, a dimensioning procedure for open core downdraft gasifiers was set up, by the analysis on the fundamental thermo-physical and thermo-chemical mechanisms which are supposed to regulate the main solid conversion steps involved in the gasification process. Gasification units were schematically subdivided in four reaction zones, respectively corresponding to biomass heating, solids drying, pyrolysis and char gasification processes, and the time required for the full development of each of these steps was correlated to the kinetics rates (for pyrolysis and char gasification processes only) and to the heat and mass transfer phenomena from gas to solid phase. On the basis of this analysis and according to the kinetic free model results and biomass physical properties (particles size, above all) it was achieved that for all the considered materials char gasification step is kinetically limited and therefore temperature is the main working parameter controlling this step. Solids drying is mainly regulated by heat transfer from bulk gas to the inner layers of particles and the corresponding time especially depends on particle size. Biomass heating is almost totally achieved by the radiative heat transfer from the hot walls of reactor to the bed of material. For pyrolysis, instead, working temperature, particles size and the same nature of biomass (through its own pyrolysis heat) have all comparable weights on the process development, so that the corresponding time can be differently depending on one of these factors according to the particular fuel is gasified and the particular conditions are established inside the gasifier. The same analysis also led to the estimation of reaction zone volumes for each biomass fuel, so as a comparison among the dimensions of the differently fed gasification units was finally accomplished. Each biomass material showed a different volumes distribution, so that any dimensioned gasification unit does not seem to be suitable for more than one biomass species. Nevertheless, since reactors diameters were found out quite similar for all the examined materials, it could be envisaged to design a single units for all of them by adopting the largest diameter and by combining together the maximum heights of each reaction zone, as they were calculated for the different biomasses. A total height of gasifier as around 2400mm would be obtained in this case. Besides, by arranging air injecting nozzles at different levels along the reactor, gasification zone could be properly set up according to the particular material is in turn gasified. Finally, since gasification and pyrolysis times were found to considerably change according to even short temperature variations, it could be also envisaged to regulate air feeding rate for each gasified material (which process temperatures depend on), so as the available reactor volumes would be suitable for the complete development of solid conversion in each case, without even changing fluid dynamics behaviour of the unit as well as air/biomass ratio in noticeable measure. The second part of this work dealt with the gas cleaning systems to be adopted downstream the gasifiers in order to run high efficiency CHP units (i.e. internal engines and micro-turbines). Especially in the case multi–fuel gasifiers are assumed to be used, weightier gas cleaning lines need to be envisaged in order to reach the standard gas quality degree required to fuel cogeneration units. Indeed, as the more heterogeneous feed to the gasification unit, several contaminant species can simultaneously be present in the exit gas stream and, as a consequence, suitable gas cleaning systems have to be designed. In this work, an overall study on gas cleaning lines assessment is carried out. Differently from the other research efforts carried out in the same field, the main scope is to define general arrangements for gas cleaning lines suitable to remove several contaminants from the gas stream, independently on the feedstock material and the energy plant size The gas contaminant species taken into account in this analysis were: particulate, tars, sulphur (in H2S form), alkali metals, nitrogen (in NH3 form) and acid gases (in HCl form). For each of these species, alternative cleaning devices were designed according to three different plant sizes, respectively corresponding with 8Nm3/h, 125Nm3/h and 350Nm3/h gas flows. Their performances were examined on the basis of their optimal working conditions (efficiency, temperature and pressure drops, above all) and their own consumption of energy and materials. Successively, the designed units were combined together in different overall gas cleaning line arrangements, paths, by following some technical constraints which were mainly determined from the same performance analysis on the cleaning units and from the presumable synergic effects by contaminants on the right working of some of them (filters clogging, catalysts deactivation, etc.). One of the main issues to be stated in paths design accomplishment was the tars removal from the gas stream, preventing filters plugging and/or line pipes clogging At this scope, a catalytic tars cracking unit was envisaged as the only solution to be adopted, and, therefore, a catalytic material which is able to work at relatively low temperatures was chosen. Nevertheless, a rapid drop in tars cracking efficiency was also estimated for this same material, so that an high frequency of catalysts regeneration and a consequent relevant air consumption for this operation were calculated in all of the cases. Other difficulties had to be overcome in the abatement of alkali metals, which condense at temperatures lower than tars, but they also need to be removed in the first sections of gas cleaning line in order to avoid corrosion of materials. In this case a dry scrubber technology was envisaged, by using the same fine particles filter units and by choosing for them corrosion resistant materials, like ceramic ones. Besides these two solutions which seem to be unavoidable in gas cleaning line design, high temperature gas cleaning lines were not possible to be achieved for the two larger plant sizes, as well. Indeed, as the use of temperature control devices was precluded in the adopted design procedure, ammonia partial oxidation units (as the only considered methods for the abatement of ammonia at high temperature) were not suitable for the large scale units, because of the high increase of reactors temperature by the exothermic reactions involved in the process. In spite of these limitations, yet, overall arrangements for each considered plant size were finally designed, so that the possibility to clean the gas up to the required standard degree was technically demonstrated, even in the case several contaminants are simultaneously present in the gas stream. Moreover, all the possible paths defined for the different plant sizes were compared each others on the basis of some defined operational parameters, among which total pressure drops, total energy losses, number of units and secondary materials consumption. On the basis of this analysis, dry gas cleaning methods proved preferable to the ones including water scrubber technology in al of the cases, especially because of the high water consumption provided by water scrubber units in ammonia adsorption process. This result is yet connected to the possibility to use activated carbon units for ammonia removal and Nahcolite adsorber for chloride acid. The very high efficiency of this latter material is also remarkable. Finally, as an estimation of the overall energy loss pertaining the gas cleaning process, the total enthalpy losses estimated for the three plant sizes were compared with the respective gas streams energy contents, these latter obtained on the basis of low heating value of gas only. This overall study on gas cleaning systems is thus proposed as an analytical tool by which different gas cleaning line configurations can be evaluated, according to the particular practical application they are adopted for and the size of cogeneration unit they are connected to.

Grenzflächenspannung und Morphologie fließender zweiphasiger Polymermischungen

In der vorliegenden Arbeit wurde die Morphologie von zweiphasigen Polymermischungen unter Scherung in situ mit Hilfe einer Kombination aus optischer Scherzelle, Durchlichtmikroskop und computergestützten CCD-Kamera untersucht. Als Modellblends dienten die unverträglichen, bei Raumtemperatur flüssigen Polymersysteme Polyisobutylen (PIB)/Polydimethylsiloxan (PDMS) (I) und Poly(dimethyl-co-methylphenyl)siloxan/PDMS (II). Alle Komponenten verhalten sich bei den verwendeten Scherraten newtonisch.Eine der wichtigsten Einflussgrößen für die Blendmorphologie ist die Grenzflächenspannung gamma 12. Sie wurde für I und II mit Hilfe der Methode der Tropfenrelaxation (dynamisch) als Funktion der Zeit bestimmt. Diese Methode erlaubt die Messung von gamma 12 für Tropfen der Phase A in B sowie von Tropfen B in A. Bei der Methode des hängenden Tropfens (statisch) muss der Tropfen aus der Phase mit der höheren Dichte bestehen. Wo der Vergleich der beiden Methoden möglich ist, stimmen die Ergebnisse für beide Systeme sehr gut überein. Bei II sind die aus der Tropfenrelaxation erhaltenen gamma 12-Werte der beiden komplementären Zusammensetzungen im Rahmen des Fehlers gleich, bei I zeigt ein PIB-Tropfen in PDMS einen um 40 % niedrigeren Wert als ein PDMS-Tropfen in PIB, dies wird auf die Diffusion von kurzkettigen Anteilen des PDMS in die Grenzschicht zurückgeführt. Die Grenzflächenspannung hängt also unter Umständen auch bei binären Systemen deutlich von der Zusammensetzung ab.Für II wurde die Blendmorphologie über den gesamten Zusammensetzungsbereich untersucht. Die häufig beobachteten cokontinuierlichen Strukturen treten bei keiner Zusammensetzung auf. Die Phaseninversion erkennt man in einer sprunghaften Änderung der Tropfengröße zwischen phiPDMS <= 0,400 und 0,500; zudem lässt sich die Zeitabhängigkeit der Radien durch Auftragung gegen das Produkt aus der Deformation und dem Quadrat des Volumenbruchs der Tropfenphase für 0 <= phiPDMS <= 0,400 sowie 0,500 <= phiPDMS <= 1 normieren. Für I und II wurde die Morphologieentwicklung bei 25 °C nach Vorscherung bei 100 bzw. 50 s-1 und anschließendem Sprung der Scherrate auf deutlich niedrigere Werte als Funktion der Zeit verfolgt. Hierbei erhält man bei genügend langer Messdauer (mindestens 200 000-300 000 Schereinheiten) konstante Tropfengrößen. Zum einen handelt es sich dabei um pseudo-stationäre Werte, die nur durch Koaleszenz bestimmt sind, zum anderen um echte stationäre Radien, die durch gleichzeitig ablaufende Koaleszenz und Zerteilung entstehen. Für I liegen die stationären Mittelwerte auf der Zerteilungskurve, für II hingegen auf der Koaleszenzkurve.Der Einfluss eines grenzflächenwirksamen Additivs wurde anhand von I durch Zugabe des Blockcopolymer PIB-b-PDMS zu PIB untersucht. Der Vergleich des zeitlichen Verlaufs von gamma 12 mit der Morphologieentwicklung zeigt, dass das Additiv eine Stabilisierung der feinen Tropfen/Matrix-Struktur des Blends durch Hinderung der Koaleszenz und nicht durch Reduktion der Grenzflächenspannung bewirkt.

Application of innovative methods of source apportionment in air contamination assessment

In this work, new tools in atmospheric pollutant sampling and analysis were applied in order to go deeper in source apportionment study. The project was developed mainly by the study of atmospheric emission sources in a suburban area influenced by a municipal solid waste incinerator (MSWI), a medium-sized coastal tourist town and a motorway. Two main research lines were followed. For what concerns the first line, the potentiality of the use of PM samplers coupled with a wind select sensor was assessed. Results showed that they may be a valid support in source apportionment studies. However, meteorological and territorial conditions could strongly affect the results. Moreover, new markers were investigated, particularly focusing on the processes of biomass burning. OC revealed a good biomass combustion process indicator, as well as all determined organic compounds. Among metals, lead and aluminium are well related to the biomass combustion. Surprisingly PM was not enriched of potassium during bonfire event. The second research line consists on the application of Positive Matrix factorization (PMF), a new statistical tool in data analysis. This new technique was applied to datasets which refer to different time resolution data. PMF application to atmospheric deposition fluxes identified six main sources affecting the area. The incinerator’s relative contribution seemed to be negligible. PMF analysis was then applied to PM2.5 collected with samplers coupled with a wind select sensor. The higher number of determined environmental indicators allowed to obtain more detailed results on the sources affecting the area. Vehicular traffic revealed the source of greatest concern for the study area. Also in this case, incinerator’s relative contribution seemed to be negligible. Finally, the application of PMF analysis to hourly aerosol data demonstrated that the higher the temporal resolution of the data was, the more the source profiles were close to the real one.

Polymer brushes - Wetting properties and my-patterning

In this work polymer brushes on both flat and curved substrates were prepared by grafting from and grafting to techniques. The brushes on flat substrates were patterned on the µm-scale with the use of an inkjet printer. Thus it was demonstrated that chemistry with an inkjet printer is feasible. The inkjet printer was used to deposit microdroplets of acid. The saponification of surface-immobilized ATRP initiators containing an ester bond occurred in these microdroplets. The changes in the monolayer of ester molecules due to saponification were amplified by SI-ATRP. It was possible to correlate the polymer brush thickness to effectiveness of saponification. The use of an inkjet printer allowed for simultaneously screening of parameters such as type of acid, concentration of acid, and contact time between acid and surface. A dip-coater was utilized in order to test the saponification independent of droplet evaporation. The advantage of this developed process is its versatility. It can be applied to all surface-immobilized initiators containing ester bonds. The technique has additionally been used to selectively defunctionalize the initiator molecules covering a microcantilever on one side of a cantilever. An asymmetric coating of the cantilever with polymer brushes was thus generated. An asymmetric coating allows the use of a microcantilever for sensing applications. The preparation of nanocomposites comprised of polyorganosiloxane microgel particles functionalized with poly(ethyl methacrylate) (PEMA) brushes and linear, but entangled, PEMA chains is described in the second major part of this thesis. Measurement of the interparticle distance was performed using scanning probe microscopy and grazing incidence small angle X-ray scattering. The matrix molecular weight at which the nanocomposite showed microphase separation was related to abrupt changes in inter-particle distance. Microphase separation occurred once the matrix molecular exceeded the molecular weight of the brushes. The trigger for the microphase separation was a contraction of the polymer brushes, as the measurements of inter-particle distance have revealed. The brushes became impenetrable for the matrix chains upon contraction and thus behaved as hard spheres. The contraction led to a loss of anchoring between particles and matrix, as shown by nanowear tests using an atomic force microscope. Polyorganosiloxane microgel particles were functionalized with 13C enriched poly(ethyl methacrylate) brushes. New synthetic pathways were developed in order to enrich not the entire brush with 13C, but only exclusively selected regions. 13C chemical shift anisotropy, an advanced NMR technique, can thus be used in order to gather information about the extended conformations in the 13C enriched regions of the PEMA chains immobilized on the µ-gel-g-PEMA particles. The third part of this thesis deals with the grafting to of polymeric fullerene materials on silicon substrates. Active ester chemistry was employed in order to prepare the polymeric fullerene materials and graft these materials covalently on amino-functionalized silicon substrates.rn

Modeling of temperature and turbidity in a natural lake and a reservoir connected by pumped-storage operations

Pumped-storage (PS) systems are used to store electric energy as potential energy for release during peak demand. We investigate the impacts of a planned 1000 MW PS scheme connecting Lago Bianco with Lago di Poschiavo (Switzerland) on temperature and particle mass concentration in both basins. The upper (turbid) basin is a reservoir receiving large amounts of fine particles from the partially glaciated watershed, while the lower basin is a much clearer natural lake. Stratification, temperature and particle concentrations in the two basins were simulated with and without PS for four different hydrological conditions and 27 years of meteorological forcing using the software CE-QUAL-W2. The simulations showed that the PS operations lead to an increase in temperature in both basins during most of the year. The increase is most pronounced (up to 4°C) in the upper hypolimnion of the natural lake toward the end of summer stratification and is partially due to frictional losses in the penstocks, pumps and turbines. The remainder of the warming is from intense coupling to the atmosphere while water resides in the shallower upper reservoir. These impacts are most pronounced during warm and dry years, when the upper reservoir is strongly heated and the effects are least concealed by floods. The exchange of water between the two basins relocates particles from the upper reservoir to the lower lake, where they accumulate during summer in the upper hypolimnion (10 to 20 mg L−1) but also to some extent decrease light availability in the trophic surface layer.

TRENDS IN PARTICULATE MATTER AND MORTALITY: AN APPROACH TO THE ASSESSMENT OF UNMEASURED CONFOUNDING

We propose a method for diagnosing confounding bias under a model which links a spatially and temporally varying exposure and health outcome. We decompose the association into orthogonal components, corresponding to distinct spatial and temporal scales of variation. If the model fully controls for confounding, the exposure effect estimates should be equal at the different temporal and spatial scales. We show that the overall exposure effect estimate is a weighted average of the scale-specific exposure effect estimates. We use this approach to estimate the association between monthly averages of fine particles (PM2.5) over the preceding 12 months and monthly mortality rates in 113 U.S. counties from 2000-2002. We decompose the association between PM2.5 and mortality into two components: 1) the association between “national trends” in PM2.5 and mortality; and 2) the association between “local trends,” defined as county-specificdeviations from national trends. This second component provides evidence as to whether counties having steeper declines in PM2.5 also have steeper declines in mortality relative to their national trends. We find that the exposure effect estimates are different at these two spatio-temporalscales, which raises concerns about confounding bias. We believe that the association between trends in PM2.5 and mortality at the national scale is more likely to be confounded than is the association between trends in PM2.5 and mortality at the local scale. If the association at the national scale is set aside, there is little evidence of an association between 12-month exposure to PM2.5 and mortality.

Dendritic cells and macrophages form a transepithelial network against foreign particulate antigens

Fine particles (0.1-2.5 microm in diameter) may cause increased pulmonary morbidity and mortality. We demonstrate with a cell culture model of the human epithelial airway wall that dendritic cells extend processes between epithelial cells through the tight junctions to collect particles in the "luminal space" and to transport them through cytoplasmic processes between epithelial cells across the epithelium or to transmigrate through the epithelium to take up particles on the epithelial surface. Furthermore, dendritic cells interacted with particle-loaded macrophages on top of the epithelium and with other dendritic cells within or beneath the epithelium to take over particles. By comparing the cellular interplay of dendritic cells and macrophages across epithelial monolayers of different transepithelial electrical resistance, we found that more dendritic cells were involved in particle uptake in A549 cultures showing a low transepithelial electrical resistance compared with dendritic cells in16HBE14o cultures showing a high transepithelial electrical resistance 10 min (23.9% versus 9.5%) and 4 h (42.1% versus 14.6%) after particle exposition. In contrast, the macrophages in A549 co-cultures showed a significantly lower involvement in particle uptake compared with 16HBE14o co-cultures 10 min (12.8% versus 42.8%) and 4 h (57.4% versus 82.7%) after particle exposition. Hence we postulate that the epithelial integrity influences the particle uptake by dendritic cells, and that these two cell types collaborate as sentinels against foreign particulate antigen by building a transepithelial interacting cellular network.

Geophysical and geological analysis of the Collingwood Member of the Trenton Formation

The Collingwood Member is a mid to late Ordovician self-sourced reservoir deposited across the northern Michigan Basin and parts of Ontario, Canada. Although it had been previously studied in Canada, there has been relatively little data available from the Michigan subsurface. Recent commercial interest in the Collingwood has resulted in the drilling and production of several wells in the state of Michigan. An analysis of core samples, measured laboratory data, and petrophysical logs has yielded both a quantitative and qualitative understanding of the formation in the Michigan Basin. The Collingwood is a low permeability and low porosity carbonate package that is very high in organic content. It is composed primarily of a uniformly fine grained carbonate matrix with lesser amounts of kerogen, silica, and clays. The kerogen content of the Collingwood is finely dispersed in the clay and carbonate mineral phases. Geochemical and production data show that both oil and gas phases are present based on regional thermal maturity. The deposit is richest in the north-central part of the basin with thickest deposition and highest organic content. The Collingwood is a fairly thin deposit and vertical fractures may very easily extend into the surrounding formations. Completion and treatment techniques should be designed around these parameters to enhance production.

Production of liquid core-polymer shell microcapsules

Polylactide (PLA) is a biodegradable polymer that has been used in particle form for drug release, due to its biocompatibility, tailorable degradation kinetics, and desirable mechanical properties. Active pharmaceutical ingredients (APIs) may be either dissolved or encapsulated within these biomaterials to create micro- or nanoparticles. Delivery of an AIP within fine particles may overcome solubility or stability issues that can result in early elimination or degradation of the AIP in a hostile biological environment. Furthermore, it is a promising method for controlling the rate of drug delivery and dosage. The goal of this project is to develop a simple and cost-effective device that allows us to produce monodisperse micro- and nanocapsules with controllable size and adjustable sheath thickness on demand. To achieve this goal, we have studied the dual-capillary electrospray and pulsed electrospray. Dual-capillary electrospray has received considerable attention in recent years due to its ability to create core-shell structures in a single-step. However, it also increases the difficulty of controlling the inner and outer particle morphology, since two simultaneous flows are required. Conventional electrospraying has been mainly conducted using direct-current (DC) voltage with little control over anything but the electrical potential. In contrast, control over the input voltage waveform (i.e. pulsing) in electrospraying offers greater control over the process variables. Poly(L-lactic acid) (PLLA) microspheres and microcapsules were successfully fabricated via pulsed-DC electrospray and dual-capillary electrospray, respectively. Core shell combinations produced include: Water/PLLA, PLLA/polyethylene glycol (PEG), and oleic Acid/PLLA. In this study, we designed a novel high-voltage pulse forming network and a set of new designs for coaxial electrospray nozzles. We also investigated the effect of the pulsed voltage characteristics (e.g. pulse frequency, pulse amplitude and pulse width) on the particle’s size and uniformity. We found that pulse frequency, pulse amplitude, pulse width, and the combinations of these factors had a statistically significant effect on the particle’s size. In addition, factors such as polymer concentration, solvent type, feed flow rate, collection method, temperature, and humidity can significantly affect the size and shape of the particles formed.

Study of particle movement in the nearshore region of Lake Superior with radioisotope tracers

Biogeochemical processes in the coastal region, including the coastal area of the Great Lakes, are of great importance due to the complex physical, chemical and biological characteristics that differ from those on either the adjoining land or open water systems. Particle-reactive radioisotopes, both naturally occurring (210Pb, 210Po and 7Be) and man-made (137Cs), have proven to be useful tracers for these processes in many systems. However, a systematic isotope study on the northwest coast of the Keweenaw Peninsula in Lake Superior has not yet been performed. In this dissertation research, field sampling, laboratory measurements and numerical modeling were conducted to understand the biogeochemistry of the radioisotope tracers and some particulate-related coastal processes. In the first part of the dissertation, radioisotope activities of 210Po and 210Pb in a variability of samples (dissolved, suspended particle, sediment trap materials, surficial sediment) were measured. A completed picture of the distribution and disequilibrium of this pair of isotopes was drawn. The application of a simple box model utilizing these field observations reveals short isotope residence times in the water column and a significant contribution of sediment resuspension (for both particles and isotopes). The results imply a highly dynamic coastal region. In the second part of this dissertation, this conclusion is examined further. Based on intensive sediment coring, the spatial distribution of isotope inventories (mainly 210Pb, 137Cs and 7Be) in the nearshore region was determined. Isotope-based focusing factors categorized most of the sampling sites as non- or temporary depositional zones. A twodimensional steady-state box-in-series model was developed and applied to individual transects with the 210Pb inventories as model input. The modeling framework included both water column and upper sediments down to the depth of unsupported 210Pb penetration. The model was used to predict isotope residence times and cross-margin fluxes of sediments and isotopes at different locations along each transect. The time scale for sediment focusing from the nearshore to offshore regions of the transect was on the order of 10 years. The possibility of sediment longshore movement was indicated by high inventory ratios of 137Cs: 210Pb. Local deposition of fine particles, including fresh organic carbon, may explain the observed distribution of benthic organisms such as Diporeia. In the last part of this dissertation, isotope tracers, 210Pb and 210Po, were coupled into a hydrodynamic model for Lake Superior. The model was modified from an existing 2-D finite difference physical-biological model which has previously been successfully applied on Lake Superior. Using the field results from part one of this dissertation as initial conditions, the model was used to predict the isotope distribution in the water column; reasonable results were achieved. The modeling experiments demonstrated the potential for using a hydrodynamic model to study radioisotope biogeochemistry in the lake, although further refinements are necessary.