In this study, the impact of galvanic coupling of magnesium to steel on the corrosion rate, surface morphology, and surface film formation was investigated. In particular, the role of self-corrosion was quantified as previous studies showed discrepancies between model predictions and experimental results that were likely due to significant self-corrosion. This experimental study examined the corrosion of Mg coupled to steel in 5 wt% NaCl at cathode-to-anode area ratios that ranged from 5 to 27. Results showed that self-corrosion was significant and accounted for, on average, one-third of total corrosion. Moreover, self-corrosion varied with time and cathode size, and was accelerated by the high dissolution rate. Film formation was observed on the magnesium surface that inhibited the corrosion rates. This film contained approximately 30% of the Mg lost to corrosion. The morphology of the coupled Mg showed the rapid formation of pits with considerable depth, and was quite distinct from previously studied filiform and disk corrosion for uncoupled Mg. This study demonstrates the important role of self-corrosion during galvanic corrosion of Mg and the need to account for such corrosion when predicting corrosion rates. This study also provides important insight into the processes that control Mg corrosion under several conditions.

Understanding the contingencies that explain whether divorce has positive or negative long-term effects for adult children is at the heart of this study. Although previous studies suggest an association between parental divorce and the divorce of adult offspring, less known is about whether the timing of divorce influences the relationship outcomes of adult children. Using a large nationally representative sample in terms of race (N=6,066), eight groups of individuals (males and females from intact homes, males and females who experienced divorce during adolescence, males and females who experienced divorce during middle childhood, and males and females who experienced divorce during preschool years) were analyzed to examine the impact of divorce and its timing on family impact, emotional regulation, and relationship quality. Findings indicate that divorce, in general, negatively influences family impact, emotional regulation, and relationship quality. However, the developmental timing of divorce does not appear to significantly alter the impact of these variables on relationship quality.

[pt] As substâncias psicodélicas clássicas são agonistas serotoninérgicos que atuam essencialmente no sistema de neurotransmissão 5HT2A. Essas substâncias podem promover estados alterados de consciência, bem como alterações visuais, afetivas, de humor e alterações cognitivas. Historicamente, eles têm sido usados para fins ritualísticos, recreativos e medicinais. Estudos indicam que essas substâncias apresentam baixa toxicidade, baixo risco de dependência e overdose. Existe um interesse científico atual no uso dessas substâncias como tratamento para uma variedade de condições e, embora muitos estudos busquem investigar objetivamente os resultados vinculados ao seu uso, os conteúdos subjetivos da experiência dos usuários ainda são pouco explorados. Considerando que a perspectiva de primeira pessoa é central para a experiência psicodélica, esta tese buscou investigar experiências subjetivas ligadas a psicodélicos por meio de uma variedade de abordagens. Primeiramente, buscou-se adaptar e validar o Ego Dissolution Inventory (EDI), instrumento amplamente utilizado por pesquisadores para avaliar um fenômeno essencial da experiência psicodélica, para o contexto brasileiro (Artigo 1). Em seguida, buscou-se explorar relatos públicos negativos (Artigo 2) e positivos (Artigo 3) de usuários de psilocibina (princípio ativo dos cogumelos mágicos), por meio do método Reinert, que analisa quantitativamente as falas transcritas. Por fim, discutiu-se a possível influência dos estados alterados de consciência (ASC), incluindo aqueles relacionados ao uso de substâncias psicoativas, na evolução humana (Artigo 4), sugerindo futuras pesquisas para explorar essa hipótese. / [en] Classical psychedelic substances are serotonergic agonists that act essentially on the 5HT2A neurotransmission system. These substances can promote altered states of consciousness, as well as visual, affective, mood, and cognitive changes. Historically, they have been used for ritualistic, recreational, and medicinal purposes. Studies indicate that these substances have low toxicity, low risk of dependence and overdose. There is current scientific interest in the use of these substances as a treatment for a variety of conditions, and while many studies seek to objectively investigate outcomes linked to their use, the subjective contents of the experience of users is seldom explored. Since a first-person perspective is central to the psychedelic experience, this thesis sought to investigate subjective experiences linked to psychedelics through a variety of approaches. First, we sought to adapt and validate the Ego Dissolution Inventory (EDI), an instrument widely used by researchers to assess a central feature of the psychedelic experience, to the Brazilian context (Article 1). Then, we sought to explore public negative (Article 2) and positive (Article 3) reports of psilocybin (the active principle of magic mushrooms) users, through the Reinert method, which quantitatively analyses transcribed speeches. Finally, the possible influence of altered states of consciousness (ASC), including those linked to use of psychoactive substances, in human evolution was discussed (Article 4), suggesting future research to explore this hypothesis.

One of the challenges of biopharmaceutics research is correlating in vitro drug release information with the in vivo drug profiles often known as in vitro-in vivo correlations (IVIVC). These have huge cost savings in pharmaceutical industry. This dissertation describes the development of a novel in vitro dissolution model that has been designed to evaluate the in vitro release of poorly water-soluble model compounds so as to predict their in vivo behavior. The flow through apparatus (USP 4) has been coupled with the compendial dissolution apparatus (USP 2). A bi-phasic dissolution medium has been used to achieve sink conditions. The dissolved drug from the aqueous phase is continuously extracted into the organic phase of the biphasic dissolution medium, mimicking the dynamic process of in vivo absorption. The model can successfully discriminate between the bioequivalent and non-bioequivalent formulations and can be used to establish IVIVC. It was concluded that the model will serve as a surrogate for bioequivalence studies and to support biowaivers.

Stress corrosion, SC, in some cases gives rise to stress corrosion cracking, SCC, which differs from purely stress intensity driven cracks in many aspects. They initiate and grow under the influence of an aggressive environment in a stressed substrate. They grow at low load and may branch. The phenomenon of SCC is very complex, both the initiation phase and crack extension itself of SCC is seemingly associated with arbitrariness due to the many unknown factors controlling the process. Such factors could be concentration of species in the environment, stress, stress concentration, electrical conditions, mass transport, and so on.In the present thesis, chemically assisted crack initiation and growth is studied with special focus on the initiation and branching of cracks. Polycarbonate plates are used as substrates subjected to an acetone environment. Experimental procedures for examining initiation and branching in polycarbonate are presented. An optical microscope is employed to study the substrate.The attack at initiation is quantified from pits found on the surface, and pits that act as origin for cracks is identified and the distribution is analysed. A growth criterion for surface cracks is formulated from the observations, and it is used to numerically simulate crack growth. The cracks are seen to coalesce, and this phenomenon is studied in detail. Branching sites of cracks growing in the bulk of polycarbonate are inspected at the sample surface. It is found that the total width of the crack branches are approximately the same as the width of the original crack. Also, angles of the branches are studied. Further, for comparison the crack growth in the bulk is simulated using a moving boundary problem based algorithm and similar behaviour of crack branching is found. / <p>Both papers in thesis as manuscript, paper II with title "Branching cracks in a layered material - Dissolution driven crack growth in polycarbonate"</p>

Användningen av cellulosa och lignin för prekursorfibrer (PF) för kolfibrer (CF) är ett mycket intressant forskningsområde på grund av den stora miljöpåverkan som dagens PF-fossilbaserade råvara PAN har. Denna avhandling fokuserar på att utveckla PF med ett kallt NaOH-upplösningssystem med cellulosakoncentrationer från 4,5 till 5,5 viktprocent med varierande massaviskositet och tillsats av lignin från 0-40 viktprocent jämfört med cellulosa. Koagulationssystemet som användes var ett fosforbaserat system med fosforsyra och ammoniumdivätefosfat (ADP) och tvätttiden ändrades för att undersöka påverkan på det slutliga oorganiska innehållet i PF. Effekten av tillsatt lignin och användning av en högre massaviskositet med en förändrad cellulosakoncentration undersöktes. Det som noterades av resultatet av dragegenskaperna och spinnbarheten hos dopen visar en viss trend som är att hög massaviskositet på 330 ml/g och hög ligninhalt på 40 viktprocent (i jämförelse med cellulosamängden i dopen) tycks uppvisa dålig spinnbarhet och svagare dragegenskaper. Användning av längre tvätttider under centrifugeringsprocessen resulterade i en lägre ask- och fosforhalt i PF. / The use of cellulose and lignin for precursor fibers (PFs) for carbon fibers (CFs) is a highly researched topic because of the large environmental impact that today’s PF raw material PAN which is fossil based. This thesis focuses of developing PFs with a cold NaOH dissolution system with cellulose concentrations ranging from 4.5 to 5.5 wt% with varying pulp viscosity and the addition of lignin ranging from 0-40 wt% in comparison to the cellulose. The coagulation system used was a phosphorus-based system with phosphoric acid and ammonium dihydrogen phosphate (ADP) and the washing time was altered to investigate the impact on the final inorganic content in the PF. The impact of the addition of lignin and using a higher pulp viscosity with an altered cellulose concentration is researched. What was noticed from the result of the tensile properties and the spinnability of the dope shows a certain trend which is that high pulp viscosity of 330 ml/g and a high lignin content of 40 wt% (in comparison to the cellulose amount in the dope) seems to present poor spinnability and weaker tensile properties. Using longer washing times during the spinning process resulted in a lower ash and phosphorus content in the PF.

No description available.

Well-preserved and diverse assemblages of late Campanian-Maastrichtian age (76.5-65.5 Ma) planktic foraminifera from Ocean Drilling Program Sites 1209 and 1210 on Shatsky Rise provide an excellent source of data to better understand the environmental and biotic changes of the end-Cretaceous Period in the tropical Pacific. A thorough taxonomic and biostratigraphic study of planktic foraminifera has revealed significant differences in species ranges when compared to detailed studies from the western North Atlantic and eastern South Atlantic. These observations are attributed to site locations with different ocean current and productivity conditions. During the globally recognized “mid-Maastrichtian Event”, inoceramid clams, rare at Shatsky Rise, dramatically increased (~69.3 Ma) before suddenly going extinct (69.1 Ma). This Inoceramid Acme Event (IAE), occurs during high sedimentation rates (~21.8-m/myr) and is indicated in planktic foraminifera by a 0.50‰ positive shift in δ18O values (~2 °C cooling), a 0.24‰ negative shift in δ13C values of and high species richness. A simultaneous decrease in both the δ18O and δ13C gradients between surface and thermocline dwelling planktic foraminifera indicate the IAE was possibly initiated by an increase in surface productivity due to the upwelling of cooler, nutrient-rich waters. A dissolution event was identified at ~66.1 Ma lasting to the Cretaceous/Paleogene boundary (65.5 Ma) and is characterized by chalky, highly fragmented planktic foraminifera, increased dissolution of larger Globotruncanids, increased small (< 63 μm) planktic foraminifera, large and increasingly abundant benthic foraminifera, a sharp decrease in species richness and increased sedimentation rates (~19.9-m/myr). This event follows a transitional interval at ~66.7 Ma where preservation is highly variable. The dissolution event, reported in previous studies at Shatsky Rise (Caron, 1975; Premoli Silva et al., 2005), is not reported in the North and South Atlantic but may help to explain the high diachroneity in species occurrences between ocean basins. These events may indicate that the calcite carbonate compensation depth (CCD) shoaled to shallower depths than previously reported (Theirstein, 1979) due to changing deep or intermediate water mass sources. Alternatively, the timing the dissolution is approximately coincident with the main pulse of Deccan Trap volcanism on the Indian subcontinent suggesting a possible link through ocean acidification.

No description available.

This dissertation includes theoretical and applied components that address the effect of coatings on rates of mineral reactions that occur in acid mine drainage (AMD) environments. The two major projects investigated how diffusion-limited transport of reactants through pore spaces in coatings on mineral grains affects the reaction rate of the underlying mineral. The first project considered the growth of gypsum coatings on the surface of dissolving limestone in anoxic limestone drains (ALD), which reduces the neutralization rate of the dissolving limestone and the subsequent effectiveness of this treatment. The second project investigated the conditions where iron oxyhydroxide coatings form on oxidizing pyrite and the potential strategies to prevent "runaway" AMD by reducing the rate of acid production to the point that the acid can be neutralized by the surrounding rocks. In both studies, experiments were conducted to measure reaction rates for the underlying minerals, as coatings grew thicker. These experimental data were fit to a diffusion model to estimate diffusion coefficients of reactants through pore spaces in coatings. These models are extrapolated to longer times to predict the behavior of the coated grains under field conditions. The experimental results indicate that management practices can be improved for ALDs and mine waste piles. For example, supersaturation with respect to gypsum, leading to coating formation, can be avoided by diluting the ALD feed solution or by replacing limestone with dolomite. AMD can be prevented if the rate of alkalinity addition to mine waste piles is faster than acid is produced by pyrite oxidation. The diffusion model developed in this study predicts when iron oxyhydroxide coatings will become thick enough that alkalinity from the surroundings is sufficient to neutralize acid produced by coated pyrite oxidation and additional alkalinity is no longer required. / Ph. D.