Made available in DSpace on 2016-04-28T14:16:22Z (GMT). No. of bitstreams: 1 Marcos dos Santos.pdf: 890332 bytes, checksum: 9c64da4f57e1bd9130331efad08c9f03 (MD5) Previous issue date: 2015-07-08 / Men always have the curiosity of observe natural phenomenon and try to understand it, for simple curiosity or taking advantage of it in his life. From this, he describes his theory to explain the phenomenon, but not all have the same view and due to different influences a lot of controversies are produced about the subject. Some of them are just small discussions and others lead to big revolutions that have an influence on man. This paper is about the importance of the controversies because it stimulates the scientific and philosophical researching that are awaked by the human curiosity, by the expecting knowledge that promotes the science development by rousing searching. A special approach is dedicated to ether theory because not even with the most brilliant minds of the world help a general approval was reached, because even in the 21th century wasn t possible to proof scientifically the existence or not of this important substance to science development / O homem sempre teve interesse em observar os fenômenos naturais e tentar entendê-los, seja pela simples curiosidade ou para deles tirar proveito em sua vida. A partir disso, ele lança suas teorias para explicar tal fenômeno, mas nem todos tem a mesma visão, devido ao fato de cada um estar sujeito a diferentes influências, o que gera muita controvérsia a respeito do assunto. Em alguns casos, trata-se de meras discussões, já em outros, levam a grandes revoluções que influenciam toda a humanidade. Esta dissertação abordará a importância das controvérsias no que concerne o papel que estas desempenham enquanto incentivadoras das pesquisas científicas e filosóficas, pois elas são despertadas pela curiosidade humana, pelo arguto anseio do homem pelo conhecimento, e portanto provocam o desenvolvimento da ciência, à medida que promovem mais pesquisas. Será dado um enfoque especial à teoria do éter, devido ao fato de que, mesmo com o auxílio das grandes mentes científicas de todos os tempos, não se chegou a um consenso geral acerca dessa substância, pois mesmo no século XXI, ainda não foi possível provar cientificamente sua existência ou não, questão primordial para o desenvolvimento científico

The ether was proposed by Enlightenment natural philosophers as an undetectable substance filling the space between the stars, that held them in place and supported the propagation of their light across space. In The Subtle Ether: A Memoir of the Space Between, insights from the history of the ether are threaded through my experience of clearing the family home after the death of my parents, and inform a reflection on ‘spaces between' memories, family members, and between ourselves and the world. This thesis both proposes and practises writing creative nonfiction as a method of first person enquiry that bears a familial resemblance to contemplative traditions, and that can acknowledge and mourn the hiddenness of things by writing into the ‘space between' ourselves and the world. Seeking a new synthesis which meshes experience, emotion, observation, and reflection on the insights of science, I employ mixed modes of lyrical, aesthetic, philosophical and personal inquiry. The central claim of this thesis is that awareness and acceptance of hiddenness as the nature of all things counteracts human hubris. While drawing from the example of continuous, open-ended questioning the scientific search for the ‘ether' offers, this thesis both argues and demonstrates that scientific and analytical methods alone cannot address this hiddenness, and that creative practice can be an effective way to think about and communicate what cannot be directly known. I argue that the desire for complete knowledge is a form of acquisitiveness and control, and that recognising the limited scope of human senses and reason undercuts human centrality and sole agency. Crafting an artwork out of contemplation of that which cannot be directly observed opens a space of reflection in which a paradoxical truth can be held in awareness; that the external reality we observe is other than us but also inseparable from us.

Na montagem de um farol automobilístico são utilizados diversos materiais, tais como insertos metálicos nas fixações, vidros nas lâmpadas, materiais poliméricos nas lentes, carcaças, molduras, vedações e refletores, além de vernizes, tintas, película de metal para reflexão do feixe luminoso. Há cerca de quatro décadas foi iniciada a confecção dos refletores utilizando o BMC (bulk moulding compound), sigla em inglês para composto para moldagem em forma de massa, que é um compósito polimérico termofixo. Este material apresenta inúmeras vantagens sobre o metal, tal como forma e geometria que podem se integrar facilmente ao desenho do carro, elevada produtividade, baixo custo e da elevada resistência térmica. Contudo, apresentam o inconveniente de não poderem ser reciclados. Uma opção ao BMC tem sido o PEI [poli (éter imida)], que é um material polimérico termoplástico de alto desempenho que apresenta propriedades atrativas para essa utilização. Oferece também elevada produtividade, porém com um custo elevado se comparado ao BMC. Tem a vantagem de pode ser reciclado. De modo a analisar o potencial dos dois materiais e extrair deles suas vantagens competitivas, bem como determinar suas possíveis limitações, o presente trabalho apresenta os resultados de caracterização mecânica, análise térmica, ensaios de impacto, ensaios de temperatura de deflexão térmica (HDT) e reaproveitamento de resíduos de BMC, incorporando-o ao PVC [poli (cloreto de vinila)], resultando uma nova blenda polimérica. O estudo conclui que ambos os materiais podem ser utilizados para fabricação de refletores automobilísticos. No entanto, o preço do PEI é maior que o do BMC, o que desestimula sua utilização em produtos de alta escala de produção, como, por exemplo, o produto do presente trabalho. O BMC por sua vez não pode ser reciclado, exigindo um custo adicional para seu reaproveitamento de maneira a evitar seu descarte em aterro sanitário. / For assembly of an automobile headlight a lot of materials are used such as metallic inserts anchors, glass in the lamps, lens of polymeric materials, bezels, frames, fences and reflectors as well as paints, metallic sheet for reflection of the luminous beam. About four decades ago begun the manufacturing of BMC reflectors, which is a thermoset composite material. This material presents countless advantages on the metal, such as shape and geometry that can easily integrate the designing of cars, high productivity, low cost and high heat resistance. However, they have the disadvantage of not being able to be recycled. An option to the BMC has been the PEI [poly (ether imide)], which is a high performance polymeric thermoplastic material which brings attractive properties for the production of reflectors. It also offers high productivity, however with a high cost compared to BMC. It also has the advantage of being recycled. In order to analyze the potential of both materials and extract their competitive advantages, as well as determine their possible limitations, this study presents the results of mechanical characterization, thermal analysis, impact tests, tests on heat deflection temperature (HDT) and the reuse of BMC waste, incorporating it to PVC [poly (vinyl chloride)], resulting in a new polymeric blend. The study concludes that both materials can be used for manufacturing automobile reflectors. However, the price of PEI is higher than the one of BMC, which discourages their use in high-scale production products, as the one of this work. The BMC for your time can not be recycled, demanding an extra cost for their reuse, avoiding its disposal in landfill.

O experimento 1 teve o objetivo de avaliar o efeito de dietas suplementadas com sais de cálcio de óleo de palma contendo diferentes concentrações (3,8% e 7,0%) de extrato etéreo (EE) e suas interações com níveis crescentes de inclusão de lisolecitina (0, 0,5 e 1 g por unidade percentual do extrato etéreo da ração) para tourinhos da raça nelore em fase de terminação. Um total de 234 tourinhos, previamente adaptados a dietas de alta energia, com peso inicial médio de 297 kg, foram alojados por 106 dias em 30 baias. O delineamento experimental utilizado foi em blocos ao acaso, em arranjo fatorial 3 x 2 (três níveis de lisolecitina e dois níveis de EE). A ingestão de matéria seca, ganho médio diário e peso corporal final foram menores para a dieta de bovinos alimentados com maior concentração de EE (P <0,05). Houve interação (P <0,1) entre o nível dietético de EE e a lisolecitina. A lisolecitina aumentou o ganho médio diário e o peso corporal final de bovinos alimentados com dietas contendo maior concentração de EE, mas não de bovinos alimentados com dietas contendo menor concentração de EE. O objetivo do experimento 2 foi avaliar o efeito de dietas com diferentes fontes de gordura (sais de cálcio de óleo de soja, sais de cálcio de óleo de palma e óleo de soja degomado) e dois níveis de lisolecitina (0 e 7 g / cabeça / dia). sobre a fermentação ruminal e digestibilidade do trato total de nutrientes. Um total de 30 novilhos Nelore foram alojados em 30 baias individuais por 30 dias (23 dias de adaptação e 7 dias de coleta). O delineamento experimental utilizado foi em blocos ao acaso, em arranjo fatorial 3 x 2 (três fontes de gordura e dois níveis de lisolecitina). Houve interação entre fontes de gordura e lisolecitina para pH ruminal (P = 0.01), proporções molares no rúmen de acetato (P <0.01), propionato (P = 0.02), isobutirato (P <0.01), valerato (P <0.01), isovalerato (P <0,01) e concentração molar de AGV total (P = 0,09). De acordo com os dados, não houve efeito de interação (P> 0,05) entre a fonte de gordura e a lisolecitina para ingestão de matéria seca e a digestibilidade aparente dos nutrientes. A lisolecitina melhorou a fermentação ruminal de dietas com óleo de soja degomado e não teve efeito sobre a digestibilidade da EE independente da fonte de gordura, mas aumentou a digestibilidade aparente de fibra no trato total. / Experiment 1 was designed to evaluate the effect of diets supplemented with calcium salts of palm oil to contain different concentrations (3.8% and 7.0%) of ether extract (EE) and their interacions with increasing levels of inclusion of Lysolecithin (0, 0.5 and 1 g per percentage unit of ether extract of the diet) for finishing Nellore bulls. A total of 234 Nelore bulls, previously adapted to high energy diets, with a mean initial body weight of 297 kg were housed for 106 days in 30 pens. The experimental design was randomized blocks in a 3 x 2 factorial arrangement (three levels of lysolecithin and two EE levels). Intakes of DM, average daily gain en final body weight were lower for cattle fed hihg EE diets (P<0.05). There was an interaction (P<0.1) between dietary EE level and Lysolecithin. Lysolecithin increased cattle average daily gain and final body weight of cattle fed hihg EE diets, but not of cattle fed low EE diets. The objective of experiment 2 was to evaluate the effect of diets with different fat sources (calcium salts of soybean oil, calcium salts of palm oil and degummed soybean oil) and two levels of inclusion of Lysolecithin (0 and 7 g/head/day) on rumen fermentation and total tract digestibility of nutrients. A total of 30 fininshing Nellore steers were housed in 30 individual pens for 30 days (23 days adptation and 7 days collection period). The experimental design was randomized blocks in a 3 x 2 factorial arrangement (three sources of fat and two levels of Lysolecithin). There was interaction between fat sources and Lysolecithin for rumen pH (P=0.01), for rumen molar proportions of acetate (P<0.01), propionate (P=0.02), isobutyrate (P<0.01), valerate (P<0.01), isovalerate (P<0.01), and molar concentration of total VFA (P=0.09). According to the data, there was no interaction effect (P>0.05) between fat source and Lysolecithin for DMI and nutrient digestibility. Lysolecithin improved rumen fermentation of diets with degummed soybean oil and had no effect on EE digestibility independent of fat source, but it increased total tract fiber digestibility.

Poly (co iso-butyl vinyl ether-alt-maleic anhydride), an alternating copolymer, was synthesised. For this class of copolymers the formation of an electron-donor complex is invoked to explain their microstructure in which the two comonomers strictly alternate. Due to its polarity, this copolymer constitutes a potential additive for imparting hydrophilic properties to a hydrophobic matrix. In order to obtain narrow molecular weight polymers and study the relation between the molecular weight of this additive and its ability to migrate to the host polymer surface, chain transfer agents were introduced in the system and also the Reversible Addition-Fragmentation chain Transfer (RAFT) process was employed. Free radical polymerisation was first carried out to allow for a comparison with the RAFT process and kinetics of copolymerisation was studied by NIR-FTIR and 1H NMR spectroscopy in order to analyse the rate of reaction of each comonomer. Dibenzyl trithiobenzoate, 3-benzyl sulfanyl thiocarbonyl sulfanyl-propionic acid and dibenzyl trithiobenzoate were used as RAFT agents. Results demonstrate that only benzyl dithiobenzoate is able to control the molecular weight of this copolymer and decrease its polydispersity index; possible reasons laying behind this result are discussed. It was also found that, in particular in the presence of benzyl dithiobenzoate, poly(iso-butyl vinyl ether) forms. This is an unusual phenomenon considering that the free radical polymerisation affords alternating copolymers and that iso-butyl vinyl ether is a monomer that polymerises through the cationic process. Experiments were carried out in various solvents in an attempt to counteract this side reaction, but no appreciable correlation between the properties of the solvents and the formation of homopolymer were found. Various hypothesis are considered, however it is likely that, in the conditions adopted, the presence of the RAFT agents alters the equilibrium constant of complex formation favouring the synthesis of the homopolymer. In addition to this side???reaction also inhibition of the copolymerisation reaction was at times encountered and an investigation into this phenomenon was also conducted.

<p>Brominated flame retardants (BFRs) are a diverse group of chemicals, which are used to slow down or inhibit the development of fires. BFRs are incorporated into a wide range of consumer products that are considered as potential fire hazards, such as TV-sets, household appliances, computers, and textiles. The production and use of BFRs is extensive and consists of mainly tetrabromobisphenol A (TBBPA), polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecan (HBCD). BFRs in general, but in particular the PBDEs, have led to both scientific and public concern since they have been found to bioaccumulate in humans and wildlife. The general population is targeted by the PBDEs due to their applications and via the food web. Occupational exposure occurs not only during direct handling of BFRs, but also during handling, repair and dismantling of flame retarded goods.</p><p>This thesis is aimed to assess occupational exposure to BFRs. It is mainly focused PBDEs and especially the PBDEs with high bromine content, such as decabromodiphenyl ether (BDE-209). The work has been accomplished by analysis of BFRs in indoor air at industries handling BFRs or flame retarded goods, and by analysis of blood drawn from workers with potential exposure to BFRs. A referent group, abattoir workers with no occupational exposure to PBDEs, was also investigated. Data from these cross-sectional investigations and from serum sampling during vacation in PBDE-exposed workers have been used for calculation of apparent halflives of hepta- to decaBDE in serum.</p><p>The results clearly show that the workers were exposed to PBDEs when handling PBDE containing products or goods. The serum PBDE levels in computer technicians were found to correlate to the estimated cumulative work hours with computers. Exceptionally high concentrations of BDE-209, almost up to 300 pmol/g lipid weight (l.w.) were observed in serum from rubber workers manufacturing or handling rubber compound that was flame retarded with a technical mixture of decabromodiphenyl ether (DecaBDE). Elevated concentrations of PBDEs with eight or nine bromine substituents were also observed. In an electronics dismantling plant, where elevated levels of PBDEs previously had been observed, reduced serum levels of some, but not all PBDE congeners were observed after industrial hygiene improvements. Notably, it was observed that the BDE-209 concentrations in referents with no occupational exposure were similar to the concentrations of 2,2’,4,4’- tetrabromodiphenyl ether (BDE-47), often referred to as the most abundant PBDE congener in humans and wildlife. Additionally, PBDEs with high bromine content were found to have a fast rate of elimination or transformation in humans, based on serum analysis. BDE-209 had an apparent half-life in serum of only 15 days.</p><p>The possibility of quantifying BFRs, such as PBDEs, in human serum at low levels of detection has been achieved by reducing the contamination of the samples and procedural blanks. Major efforts have been done to develop routines and clean up methodology to enable an almost contamination-free environment at the laboratory. The use of a clean room has decreased PBDE levels in the blanks to acceptable limits. The modifications of the original analytical method have made it possible to quantify almost all PBDE congeners of interest in one GC/MS run.</p><p>Occupational and general background exposure of BFRs to humans will continue as long as these chemicals are a part of our daily life and present as environmental contaminants. The present scientific knowledge of the potential health risks of these BFRs still needs to be further developed. It should be stressed that health effects to PBDEs have not been assessed in this work. It is the author's wish that this thesis should add another piece of knowledge to the puzzle of BFRs and BFR exposure to humans and that these data will be used in future risk assessments of PBDEs in particular.</p>

<p>Polybrominated diphenyl ethers (PBDEs) are important chemical flame retardants, but also environmental pollutants. Their bromine substitution lends them a different bioaccumulation behaviour than the better studied organochlorines.</p><p>The contamination of a Swedish lake with lower brominated BDEs was assessed by a retrospective study of pike. The concentrations of tetra- to hexaBDEs increased exponentially up to the mid-1980s and then decreased slowly, possibly reflecting the voluntary reduction in production/usage of the chemicals. Methoxylated PBDEs were found to be present in similar concentrations to the PBDEs, but originated from different sources. The large size of the bromine atom was believed to result in negligible absorption of higher brominated BDEs in wildlife, thus explaining the low levels observed in fish despite high levels in e.g. sediment. However, it was shown that the fully brominated BDE, BDE209, was absorbed to a small extent via the diet. Once absorbed, it was reductively debrominated to lower brominated BDE congeners. Debromination was also observed in dairy cows exposed to higher brominated BDEs in their natural diet. Moreover, the molecular size restricted the transfer of higher brominated BDEs to milk. In contrast to PCBs and lower brominated BDEs, there was no equilibrium between adipose tissues and milk fat, and with increasing bromine substitution a progressively smaller fraction of the ingested PBDEs was transferred to the milk.</p><p>This thesis highlights differences in uptake, metabolism and excretion for PBDEs compared to the well characterized organochlorines. A knowledge that is useful for risk assessments given the ongoing use of these compounds. Furthermore, a representative of the next generation brominated flame retardants, decabromodiphenyl ethane, a replacement for the BDE209 technical product, was identified for the first time in the environment.</p>

This dissertation summarizes research efforts focused on the use of boron and transition metal halides to form new carbon-carbon and carbon-halide bonds. The boron halide mediated alkyne-aldehyde coupling reaction to generate 1,3,5-triaryl-1,5-dihalo-1,4-dienes was reinvestigated in an attempt to explain the stereochemistry observed during changing of both the mode of addition and the reaction temperature. Either (Z,Z)-1,4-dienes or (Z,E)-1,4-dienes can be the predominant product depending on reaction conditions used. This mechanistic investigation also led to the discovery of several novel reactions. These include the stereoselective preparation of (Z)-3-chloroallylic ethers from the reaction of alkenylboron dichlorides with aryl aldehydes in the presence of an amine; the titanium(IV) halide coupling of alkoxides and alkynes; the haloallylation of aryl aldehydes with boron trihalide using different allylmetals; and the base induced elimination of the haloallylated products to form 1,3-dienes. The results of these studies strongly imply a cationic mechanism. The new reactions described herein can be characterized as atom-efficient, environmentally friendly, and capable of generating the desired products in good to excellent yields.

From the dichloromethane-methanol (1:1) extract of the seed pods of Derris trifoliata, a new flavanone derivative (S)-lupinifolin 4´-methyl ether was isolated. In addition, the known flavonoids lupinifolin and rotenone were identified. The structures were determined on the basis of spectroscopic evidence. Lupinfolin showed moderate in vitro antiplasmodial activity against the D6 (chloroquine-sensitive) and W2 (chloroquineresistant) strains of Plasmodium falciparum. The different parts of this plant showed larvicidal activities against Aedes aegypti and rotenoids were identified as the active principles.

Today’s market offers an ever-increasing range of cellulose pulps (derivative pulps) made fromvarious wood types through different delignification processes. Each pulp segment has its uniquecharacteristics, which makes it difficult for the producer of cellulose derivatives to choose the mostsuitable pulp for optimum processability and product quality. The objective of this study was toimprove knowledge of cellulose pulps and to describe how different pulp properties affectprocessability and quality in the production of viscose dope and cellulose ethers.Ten pulp samples were investigated, originating from both sulfite and sulfate processes, with highand low viscosities and with softwood and hardwood as raw material. The pulps were analyzed fortheir properties and then processed to viscose dope and a cellulose ether in two separate pilotfacilities. The intermediates in the viscose process as well as the quality of the viscose dope andcellulose ether were analyzed and the results correlated to pulp properties.Multivariate regression methods were applied to investigate the dominating physical and chemicalproperties of each pulp and pulp segment, and to study the use of spectroscopic analyses inpredicting pulp origin, concentration and composition of hemicelluloses as well as the content ofreducing end groups in cellulose. For the production of viscose dope, the models presented showedthe most important pulp properties for good cellulose reactivity and viscose filterability. In addition,the properties affecting gel formation, flocculation, degree of substitution and clarity in theproduction of cellulose ether were highlighted. The study also emphasized the need to supplementthe use of conventional analyses on pulps and viscose intermediates with other analytical methods,such as molecular weight distribution and carbohydrate analysis, to better predict the quality ofboth viscose dope and viscose fiber.The results of the present study could be useful to predict the origin and properties of new pulps, toreplace or supplement otherwise expensive pulp analyses, and to assess the impact of pulpproperties on the production of cellulose derivatives without extensive pilot-scale trials.