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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
431

Chlorine-induced lung injury and the role of iNOS

Campbell, Holly R., 1976- January 2009 (has links)
Reactive airways dysfunction syndrome (RADS), a form of irritant-induced asthma (IIA) has been observed in humans following acute chlorine (Cl 2) gas exposure in occupational and domestic settings. Following Cl 2 injury, subepithelial fibrosis, mucous hyperplasia, and non-specific airway hyperresponsiveness have been reported. Based on the disease profile, we hypothesized that pulmonary damage may be oxidative in nature. / The aim of this work was to develop a murine model of irritant-induced asthma in order to investigate the pathogenic processes and potential oxidative mechanisms involved in response to Cl2 exposure, with a secondary aim of examining the role of iNOS in response to Cl2 inhalation. / A/J, C57BI/6J (wild type) and iNOS-1- mice exposed to various concentrations of Cl2 were mechanically ventilated for measurement of lung mechanics and responses to i.v. methacholine (MCh). Bronchoalveolar lavage was performed to examine total protein, cell populations and nitrate/nitrates. Tissues were harvested for histology and immunocytochemistry for iNOS, 3NT and carbonyl residues. To examine the role of iNOS, a subset of animals were treated with a selective iNOS inhibitor (1400W) and non-selective NOS inhibitor LNAME. / Chlorine exposure caused airway hyperresponsiveness, which appeared to be mitigated by iNOS blockade with 1400W, however this was not the case in iNOS-1- mice. Cl2 exposure also caused increases in total BAL protein, total cells, NOx, neutrophils, iNOS, 3NT and carbonyl residues. / In conclusion, chlorine exposure causes lung injury, similar to reactive airways dysfunction syndrome, characterized by airway hyperresponsiveness, epithelial sloughing, inflammatory cell influx, oxidative injury and increases in both the activity and expression of iNOS. Chlorine-induced airway hyperresponsiveness is mitigated, in part, by selective blockade of iNOS with the use of pharmacological intervention.
432

Atividade antimicrobiana de ácidos orgânicos e compostos clorados sobre micro-organismos patogênicos em carne de frango / Antimicrobial activity of organic acids and chlorinated compounds over pathogenic microorganisms in poultry meat

Zabot, Sandra 30 March 2016 (has links)
O cenário atual da produção avícola brasileira é definido pela alta produtividade motivada pelas exportações para mercados com elevados níveis de exigência sanitária. O trabalho objetivou avaliar a eficácia de compostos clorados (dióxido de cloro, dicloro e tricloro) e ácidos orgânicos (ácidos cítrico, lático e peracético) na redução da contaminação de carne de frango por Salmonella spp., mesófilos e enterobactérias. Foram isoladas 102 cepas de Salmonella spp. de carcaças de frango no período de junho a setembro de 2014. As cepas foram identificadas por PCR. Determinou-se a concentração inibitória mínima (CIM) dos compostos para as cepas padrões de S. Typhimurium, S. Enteritidis e S. Heidelberg. A CIM dos ácidos lático e peracético (20 e 10 g/L) foi aplicada em cepas de Salmonella spp. isoladas do frigorífico. A CIM dos compostos ácido lático e dicloro foi aplicada em água de chiller contaminada com Salmonella (109 UFC/mL) e foi determinada a contagem de Salmonella presente na água. Coxas e sobrecoxas de frango foram contaminadas com S. Heidelberg (109 UFC/mL) e foram aplicados os compostos dicloro (60 mg/L), ácido lático (20 g/L) e hipoclorito de sódio (5,0 e 0,5 mg/L). Na identificação por PCR, 93,1% das cepas foram identificadas como Salmonella spp. Para o dicloro a CIM foi de 60 mg/L por 15 minutos para S. Heidelberg e 60 mg/L por 20 minutos para S. Enteritidis. O ácido lático apresentou CIM de 5 g/L por 10 minutos para S. Enteritidis, 10 g/L por 15 minutos para S. Typhimurium e 20 g/L por 20 minutos para S. Heidelberg. Para o ácido peracético, as CIMs foram de 10 g/L por 10 minutos para S. Typhimurium e S. Heidelberg e 10 g/L por 20 minutos para S. Enteritidis. Para o ácido cítrico, as CIMs foram de 10 g/L por 10 minutos para S. Typhimurium e S. Enteritidis e 25 g/L por 20 minutos para S. Heidelberg. Nas cepas de Salmonella isoladas, o ácido lático inibiu 97,89% das cepas e o peracético inibiu 100% das cepas. Na água de chiller contaminada os compostos reduziram o crescimento das cepas padrões. Quando aplicados em carne de frango contaminada, houve redução de Salmonella spp. de 1,06 log10 UFC/g em relação ao controle positivo com o hipoclorito de sódio a 5,0 mg/L, 0,97 log10 UFC/g com o dicloro e 0,56 log10 UFC/g com o hipoclorito de sódio a 0,5 mg/L. Para mesófilos a redução observada foi de 0,90 log10 UFC/g em relação ao controle positivo com o hipoclorito de sódio a 5,0 mg/L, 0,90 log10 UFC/g com o dicloro e não havendo redução com o hipoclorito de sódio a 0,5 mg/L. Para enterobactérias a redução foi de 1,0 log10 UFC/g em relação ao controle positivo com o hipoclorito de sódio a 5,0 mg/L, 0,79 log10 UFC/g com o dicloro e 0,22 log10 UFC/g com o hipoclorito de sódio a 0,5 mg/L. O ácido lático inibiu o crescimento bacteriano dos micro-organismos testados. Os dados obtidos reforçam a necessidade de discussões para regulamentar o uso de coadjuvantes de tecnologia no abate de aves. / The current scenario of the Brazilian poultry production is defined by high productivity motivated by exports to markets with elevated levels of sanitary requirement. The work aimed to evaluate the efficacy of chlorinated compounds (chlorine dioxide, dichloro and trichloro) and organic acids (citric, lactic and peracetic acids) in reducing the contamination of poultry by Salmonella spp., mesophiles and enterobacteriaceae. Were isolated 102 strains Salmonella spp. poultry carcass from June to September 2014. Strains were identified by PCR. Was determined the minimum inhibitory concentration (MIC) of antimicrobial compounds for the standard strains of S. Typhimurium, S. Enteritidis and S. Heidelberg. MIC of lactic acid and peracetic acid (20 to 10 g/L) was applied in strains of Salmonella spp. isolated from the slaughter. The MIC of the compounds lactic acid and sodium dichloro was applied in contaminated chiller water with Salmonella (109 CFU/mL) and this was determined Salmonella count in water. Thighs and drumsticks poultry were contaminated with S. Heidelberg (109 UFC/mL) and were applied dichloro (60 mg/L), lactic acid (20 g/L) and sodium hypochlorite (5,0 and 0,5 mg/L) compounds. In the identification by PCR, 93,1% of the strains were identified as Salmonella. For sodium dichloro the MIC was 60 mg/L for 15 minutes to S. Heidelberg and 60 mg/L for 20 minutes for S. Enteritidis. Lactic acid presented MIC of the 5 g/L for 10 minutes to S. Enteritidis 10 g/L for 15 minutes to S. Typhimurium and 20 g/L for 20 minutes to S. Heidelberg. For peracetic acid, MICs were 10 g/L for 10 minutes to S. Typhimurium and S. Heidelberg and 10 g/L for 20 minutes to S. Enteritidis. To citric acid, MICs were 10 g/L for 10 minutes to S. Typhimurium and S. Enteritidis and 25 g/L for 20 minutes to S. Heidelberg. In the isolated Salmonella strains, lactic acid inhibited 97,89% of the strains and peracetic inhibited 100% of the strains. In contaminated chiller water, the compounds reduced the growth of standards strains. When applied to contaminated poultry meat, there was a reduction of Salmonella spp. 1,06 log10 CFU/g relative to the positive control with the use of sodium hypochlorite at 5,0 mg/L, 0,97 log10 CFU/g with dichloro and 0,56 log10 CFU/g with sodium hypochlorite 0,5 mg/L. For mesophiles reduction observed was 0,90 log10 CFU/g relative to the positive control with the use of sodium hypochlorite at 5,0 mg/L, 0,83 log10 CFU/g with dichloro and there isn´t reduction with hypochlorite with sodium 0,5 mg/L. For enterobacteriaceae reduction was 1,0 log10 CFU/g relative to the positive control with the use of sodium hypochlorite at 5,0 mg/L, 0,79 log10 CFU/g with dichloro and 0,22 log10 CFU/g with sodium hypochlorite at 0,5 mg/L. Lactic acid inhibit growth of the microorganisms tested. The data supports the discussions to regulate the use of the technology coadjuvants in the slaughter of poultry.
433

Modélisation à l'échelle moléculaire des aérosols carbonés dans la troposphère / Modeling at a Molecular Scale of Carbonaceous Aerosols in the Troposphere

Radola, Bastien 27 October 2017 (has links)
Dans ce travail de thèse, des méthodes de simulation numérique ont été utilisées afin de modéliser, à l’échelle moléculaire,l’interaction entre des aérosols carbonés et diverses molécules de l’atmosphère.L’objectif était de caractériser les propriétés physico-chimiques de ces aérosols, qui jouent un rôle majeur dans le climat, en particulier via leur capacité à former des noyaux de condensation pour les molécules d’eau. En premier lieu, les techniques de la dynamique moléculaire ont été appliquées à la détermination de l’organisation d’agrégats d’acide carboxylique sur lesquels sont adsorbées des molécules d’eau. Les résultats montrent une influence à la fois de la température, du taux d’humidité et du type d’acide considéré sur le comportement global des agrégats. Par contre, il a été montré qu’un mélange binaire d’acides n’a que peu d’influence sur ce comportement. En second lieu, des techniques de simulation moléculaires quantiques, à la fois statiques et dynamiques, ont été appliquées à l’étude de la chloration de surfaces de suie, modélisées par de grands HAP, ainsi qu’à la caractérisation de leur affinité pour les molécules d’eau. Les résultats ont montré une forte propension de Cl, Cl2 et HCl à former des HAP chlorés à la faveur de la présence de défauts structurels. Ces structures chlorées présentent une forte hydrophilicité, ce qui pourrait expliquer la nature fortement hygroscopique de suies émises lors d’incendies industriels. / In this PhD work, molecular simulation methods have been used in order to model, at the molecular scale, the interaction between carbonaceous aerosols andvarious atmospheric species. The aim wasto characterize the physico-chemical properties of these aerosols, which play a major role in climate forcing, in particular through their ability to act as cloud condensation nuclei.First, molecular dynamics techniques have been applied to determine the structure of carboxylic acid aggregates on which water molecules are adsorbed. The results of our simulations show an influence of the temperature, of the humidity and of the type of carboxylic acid considered on the global behavior of the aggregates. By contrast,a mixture of different types of acid molecules has no influence on this behavior. Secondly, quantum molecular simulation techniques have been applied to study the chlorination of soot surfaces, modeled by large PAHs, and their behavior with respect to water molecules adsorption. The results show a strong propensity of Cl, Cl2and HCl species to form chlorinated PAHsthanks to the presence of structural defects.These chlorinated structures show as trong hydrophilicity, which may explain the strong hygroscopic nature of soots emitted by industrial fires.
434

Chemické omyly ve světle skutečnosti - identifikace a vysvětlení / Chemical mistakes in the light of reality - identification and explanation

Fatka, David January 2018 (has links)
This thesis deals with widespread, chemically-themed misinformation. The the- oretical part describes psychological effects leading to myth spreading. It also descri- bes the debunking possibilities of such myths and the didactic reasons for misinformation- based work on the high school level. General practical part uses methods of content analysis upon random sample of School educational programmes to prove the usability of misinformation-based work in education. It also summarizes the organisations and resources useful for myth debunking. Specific practical part deals with analysis of chosen suspicious information, their credibility and the possibilities of educational work based on them. The chosen in- formation was the "medicinal" usage of chlorine dioxide solution. Rumors of alkaline diet and alleged harmfulness of aspartame, an artificial sweetener, were also chosen. The way they tend to be presented, none of these claims are backed. In all these cases, multiple unsubstantiated claims were found among proponents of these ideas.
435

Chloration et monochloramination des aminophénols en solution aqueuse / Chlorination and monochloramination of aminophenols in aqueous solution

Abou Mehrez, Odissa 13 December 2013 (has links)
Ce travail décrit la réactivité du chlore et de la monochloramine sur les aminophénols en solution aqueuse.Cette étude a ciblé, d'une part la détermination des vitesses réactionnelles de chloration et de monochloramination des aminophénols et d'autre part, l'identification des sous-produits d'oxydation formés.Les demandes en oxydant et le potentiel de formation en composés organohalogénés adsorbables (AOX), chloroforme, acides haloacétiques (HAA) and haloacétonitriles (HAN) ont été déterminés lors de la chloration et la monochloramination des aminophénols. Les 3-aminochlorophénols et le 2-amino-3H-phénoxazin-3-one (APX) ont été respectivement identifiés lors de la monochloramination de 3AP et 2AP.L'étude cinétique de la chloration des aminophénols en réacteur continu a montré que les vitesses sont du même ordre de grandeur pour le 2-aminophénol (2AP) et le 3-aminophénol (3AP) à pH neutre. La modélisation cinétique de la chloration du 3AP a indiqué que la forme aminophénolate est la plus réactive vis-à-vis du chlore.Quant à l'étude cinétique de monochloramination du 3AP en réacteur fermé, elle a permis de conclure que la vitesse de monochloramination diminue en passant du pH 7 à 9 et la forme neutre de 3AP est la plus réactive vis-à-vis de la monochloramine. Par comparaison, la vitesse de chloration du 3AP a été plus importante d'un facteur 105 à celle de la monochloramination. / This work describes the reactivity of chlorine and monochloramine with aminophenols in aqueous solution. Chlorination and monochloramination kinetic rates of aminophenols were investigated, first and final oxidation by-products were identified.Oxidant demands and formation potential of adsorbable organic halides (AOX), chloroform, haloacetic acids (HAA) and halonitriles (HAN) were determined during the chlorination and the monochloramination of aminophenols. The 3-aminochlorophenols and the 2-amino-3H-phenoxazin-3-one (APX) were respectively identified during the monochloramination of 3AP and 2AP.Chlorination of aminophenols in a continuous flow reactor showed that the kinetic rates of 2-aminophenol (2AP) and 3-aminophenol (3AP) have the same order of magnitude at neutral pH. Kinetic modelling of 3AP chlorination indicated that aminophenolate is the most reactive species with chlorine.Monochloramination kinetics of 3AP in a batch reactor showed that the rate of monochloramination decreases when pH increases from 7 to 9 and the neutral form of 3AP is the most reactive with monochloramine. In comparison, chlorination rate of 3AP was estimated to be 105-fold higher than monochloramination rate.
436

Neodkladná a následná opatření v případě úniku chlóru - Simulovaná havárie vozidla přepravujícího chlór / The urgent and follow-up precautions in case of leakage of chlorine - Simulated accident of vehicle carrying chlorine

KADIČ, Milan January 2013 (has links)
The goal of this diploma thesis is to introduce urgent and follow-up precautions in case of leakage of chlorine - simulated accident of vehicle transporting chlorine. The major objective of this study is to analyse the risk of chlorine-transport for people with the aid of available simulation programme and to specify urgent and follow-up precautions. The next part of this study is to investigate the knowledgeability of people. The theoretical part of this study is systematical structured into a number of chapters and worked out on the basis of available legislative regulations, literature and internet sources. At first basic legislation of transport of dangerous substances is described, from the european, as well as national perspective. The next chapter deals with transport of dangerous substances, danger classes of these substances, their labeling in transport, as well as labeling of transport units. The following chapter is devoted to aspects of an accident in case of transporting of dangerous substances. This chapter demonstrates an accident with leakage of dangerous substance, its impact, escape of this substance and its spread. Further the sources and risks of transportation of dangerous substances and accident rate in this transport are described. The next chapter deals with the specific dangerous substance - chlorine. It is aimed at physico-chemical characters of chlorine, its history and its current utilisation, its effect on human health, on environment and first aid in case of contact. At the end urgent and follow-up precautions in case of an accident inkl. leakage of chlorine. The empirical part of this study is devoted to two basic research questions. Qualitative, as well as quantitative methods of research were used to answers these questions. The empirical part is devided into two major chapters. The primary purpose of this study is to simulate an accident of vehicle transporting chlorine with the aid of the programme TerEx and to determine its impact on people and surrounding. The first question was to analyse the potential dangerous for people and surroundings in case of an accident with chlorine. For this purpose the town České Budějovice was used. First the transport of liquid chlorine in small containers in the Czech Republic was analysed focusing on the southbohemian region and especially the regional city. Thereafter input data were entered. On the basis of obtained outputs were determined threats, that arise from the transport of dangerous chlorine and on the basis of simulation were characterized activities carried out by Integrated Rescue System using appropriate urgent and follow-up precautions. Part of this work was also the second research question - the level of knowledge of people located close to the simulated accident about this problem. This survey was aimed at the risk of chlorine, its transport and characteristics and impact on human health as well as protection against its adverse effects. For this purpose a group of second-year students of the local gymnasium located close to the place of simulated accident was chosen. The data were collected through a questionnaire, which contained a group of questions relating to this problem. The obtained data were evaluated using basic methods of elemental statistical analysis and graphic processing. Findings resulting from the analysis of transporting of chlorine and from the simulation using the programme TerEx show, that the danger to the population of České Budějovice in case of an accident with chlorine is significant. The issue of chlorine-transport and its risks is additionally complicated by insufficient regulation. Another negative factor of transporting of these substances is the complicated traffic situation in the country town. Based on the results of the questionary can be stated, that these students have average knowledge in this issue.
437

Aplicação de cloreto e silicato de potássio em gérbera (Gerbera jamesonii L.) de vaso

Guerrero, Amaralina Celoto [UNESP] 13 February 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:26:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-13Bitstream added on 2014-06-13T19:13:46Z : No. of bitstreams: 1 guerrero_ac_me_botfca.pdf: 1002374 bytes, checksum: af55f667f26136807fb5a775b0c88eb0 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / A produção comercial de flores e plantas ornamentais no Brasil vem aumentando, e, no entanto, a pesquisa não tem acompanhado esse ritmo de crescimento, sendo ainda escassas as informações sobre o cultivo de flores, principalmente no que diz respeito à nutrição e a adubação. Portanto, o presente trabalho foi desenvolvido com o objetivo de avaliar diferentes concentrações de potássio utilizando-se de duas fontes, cloreto e silicato, no desenvolvimento e qualidade da gérbera de vaso cultivada em ambiente protegido. O experimento foi conduzido no Departamento de Recursos Naturais / Ciência do Solo, em casa de vegetação, no período de 09 de setembro a 11 de novembro de 2008. O delineamento experimental utilizado foi em blocos casualizados, empregando o esquema fatorial 2x5, sendo duas fontes de potássio, silicato e cloreto e cinco concentrações de potássio de cada uma dessas fontes, em 4 repetições e 5 plantas por parcela, num total de 200 plantas. As concentrações para as duas fontes utilizadas foram às seguintes: 0, 50, 100, 150 e 200 mg L-1 K+ em todo o período experimental. A aplicação da solução nutritiva e a solução contendo os tratamentos foram aplicadas via fertirrigação realizada manualmente, uma vez ao dia. Avaliou-se o número de folhas e diâmetro da planta, área foliar, fitomassa fresca e seca das folhas e flores, intensidade de cor verde (ICV), condutividade elétrica e pH da solução do substrato, teor e acúmulo nutrientes e Si nas folhas e flores ao final do período vegetativo e reprodutivo, além do número e diâmetro de inflorescência, altura e diâmetro de hastes e altura da planta, no ponto de comercialização. Entre as fontes, o silicato de potássio promoveu diâmetro de planta, área foliar, fitomassa fresca e seca total mais adequada para a qualidade dos vasos quando aplicou-se a dose de 150 mg L-1 de potássio... / The commercial production of flowers and ornamental plants in Brazil is increasing, and yet, research has not kept up with this pace of growth, although little information on the cultivation of flowers, especially regarding nutrition and fertilization. Therefore, this study was conducted to evaluate using different concentrations of potassium are two sources, chloride and silicate, the development and quality of gerbera of pot grown in protected environment. The experiment was conducted at the Department of Natural Resources/Soil Science, in a greenhouse in the period from 09 September to 11 November 2008. The experimental design was randomized blocks, using a 2x5 factorial, with two sources of potassium, silicate and chloride and potassium concentrations of five of each of these sources, in 4 replicates and 5 plants per plot, total 200 plants. The concentrations for the two sources used were: 0, 50, 100, 150 and 200 mg L-1 K throughout the experimental period. The application of nutrient solution and the solution containing the treatments were applied through fertirrigation performed manually once a day. The number of leaves and diameter of plant, leaf area, fresh and dry biomass of leaves and flowers, intensity of green (ICV), electrical conductivity and pH of the solution to the substrate, and nutrient content and accumulation in leaves and Si flowers at the end of the vegetative and reproductive period, and the number and diameter of inflorescence, height and stem diameter and plant height at the point of marketing. Among the sources, the potassium silicate promoted plant diameter, leaf area, plant fresh and dry all the best for quality of vessels when applied to a dose of 150 mg L-1 potassium. When the marketing point of no interference of sources and doses to diameter of inflorescence, number of inflorescence, stem diameter and plant height, however the potassium silicate promoted... (Complete abstract click electronic access below)
438

Nouvelles conditions d'utilisation de l'ozone dans le blanchiment des pâtes cellulosiques. Application à la mise au point d'un procédé de blanchiment "vert" / New conditions of use of ozone for cellulosic pulp bleaching. Development of a green bleaching sequence

Pouyet, Frédéric 21 March 2014 (has links)
Le manque de compréhension des réactions liées à l'utilisation de l'ozone a constitué un clair frein au développement de séquences de blanchiment non-chlorées efficaces. Considéré comme un élément central des séquences TCF face aux séquences ECF comprenant du dioxyde de chlore, l'ozone ne permettait pas l'obtention de pâtes cellulosiques de qualité aussi élevée. Le but de ce travail est l'élaboration de séquences de blanchiment non-chlorées permettant l'obtention d'un produit final de haute qualité. Ce type de séquence pourrait présenter de nombreux avantages, parmi lesquels sont envisagés des gains environnementaux indéniables. Afin d'atteindre cet objectif, les réactions liées à l'ozone et au peroxyde d'hydrogène ont été étudiées plus avant. Après une revue bibliographique, cet écrit revient dans un second chapitre sur certaines hypothèses de la littérature qui, confrontées entre elles et avec certains premiers résultats, permettent de mettre en évidence certaines incohérences. Dans une troisième partie, plusieurs pâtes de compositions différentes ont été étudiées, afin de vérifier l'ordre des réactions de l'ozone sur les divers composés d'une pâte kraft, et afin également d'envisager l'ampleur des dégradations subies par la cellulose dans ces différents substrats, qu'il s'agisse de dépolymérisation, ou de modifications fonctionnelles. Ces résultats ont permis de formuler une hypothèse relative aux réactions de l'ozone sur des composés insaturés, tels que ceux des acides hexenuroniques. Par l'utilisation d'une méthode de détection rarement utilisée en papeterie, cette hypothèse a été validée : la réaction de l'ozone sur certains composés insaturés non-aromatiques pourrait générer des radicaux, eux-mêmes à l'origine de mécanismes de modification de la cellulose. D'après les résultats, l'ozone ne serait que marginalement directement responsable des dégradations de la cellulose. L'effet des différents stades alcalin a également été envisagé dans une quatrième partie. C'est ainsi que la dépolymérisation de la cellulose et ses modifications fonctionnelles ont également été analysées à l'issue de ces stades. Les résultats suggèrent notamment l'existence d'un mécanisme de dépolymérisation impliquant les carbonyles cellulosiques et des agents nucléophiles. Une grande partie de la dégradation se produisant dans les stades au peroxyde d'hydrogène lui serait ainsi imputable. Le dernier chapitre revient sur ces différentes considérations, dans l'optique de minimiser les inconvénients liés à ces différents stades, et particulièrement aux stades à l'ozone. Différentes combinaisons des réactifs ont été envisagées pour former des séquences non-chlorées. Les résultats montrent que l'obtention de pâtes de qualité comparable à celle de pâtes issues de séquences de blanchiment chlorées est possible. / The lack of understanding regarding the reactions of ozone with pulp components is one of the reasons why chlorine-free bleaching never really developed. Ozone is actually believed to lead to an extensive degradation of cellulose, contrary to the agent it could replace: chlorine dioxide. However, as the use of chlorinated compounds has many drawbacks, including the generation of toxic compounds, non-degrading chlorine-free bleaching sequences have to be designed. To do so, a better understanding of reactions involving ozone and hydrogen peroxide has to be gained. The first part of this very work consisted of a literature review. In the second part, some of the main hypotheses extracted from the literature were compared with other elements and first results, to show they inevitably led to contradictions and that new theories were needed. The third part was dedicated to ozone. The order of its reactions with pulp components was first of all checked. The properties of pulps of various compositions were then measured through ozonations. This study led to a new hypothesis, which was validated thanks to ESR spectroscopy. The reaction of ozone with some non-aromatic unsaturated compounds seems to give radical species. Those radical species would be in turn responsible for the depolymerization of cellulose, and the formation of carbonyl groups on cellulose as well. The fourth part dealt with the impact of alkaline treatment on cellulose after ozonations. Observations about carbonyl content and degree of polymerization suggest a new mechanism related to carbonyl and nucleophilic agents, explaining a main part of the depolymerization undergone by the cellulose. The last chapter of this work summarizes the trials regarding the optimisation of a chlorine-free bleaching sequence. It proves that high-quality pulps can be obtained by chlorine-free processes.
439

Aplicacao do processo avancado de oxidacao por feixe de eletrons na degradacao de compostos organicos presentes em efluentes industriais

DUARTE, CELINA L. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:43:41Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:09:56Z (GMT). No. of bitstreams: 1 06654.pdf: 9860874 bytes, checksum: a9212efd0462f2603abb2f237d62a703 (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
440

Modelagem da degradação de cloro residual livre na rede de distribuição de água da cidade de Campina Grande – PB.

SANTOS, Whelton Brito dos. 20 March 2018 (has links)
Submitted by Dilene Paulo (dilene.fatima@ufcg.edu.br) on 2018-03-20T15:47:53Z No. of bitstreams: 1 WHELTON BRITO DOS SANTOS– DISSERTAÇÃO PPGECA 2017.pdf: 2787950 bytes, checksum: 176fe1aec4e0f28aec671343bd1e4daf (MD5) / Made available in DSpace on 2018-03-20T15:47:53Z (GMT). No. of bitstreams: 1 WHELTON BRITO DOS SANTOS– DISSERTAÇÃO PPGECA 2017.pdf: 2787950 bytes, checksum: 176fe1aec4e0f28aec671343bd1e4daf (MD5) Previous issue date: 2017-03-14 / A qualidade sanitária da água é assegurada na etapa de desinfecção do processo de tratamento. No Brasil a Portaria 2.914/2011 do Ministério da Saúde, que dispõe sobre os procedimentos de controle e de vigilância da qualidade da água para consumo humano e seu padrão de potabilidade recomenda residual mínimo de cloro livre de 0,2mgCl2/L, máximo de 2,0mgCl2/L e valor máximo permitido de 5,0mgCl2/L que devem ser assegurados na rede de distribuição. Devido a fatores como, idade das tubulações, vazamentos, material, diâmetro e longas distâncias entre os sistemas de tratamento e os centros de consumo, nem sempre as concentrações recomendadas de cloro residual livre são mantidas em todos os pontos da rede de distribuição de água. Este trabalho tem como objetivo modelar o decaimento do cloro residual livre na rede de distribuição da cidade de Campina Grande, Paraíba, através da determinação dos coeficientes cinéticos de degradação da concentração de cloro residual livre no volume do escoamento (kb), pelo teste da garrafa, e na parede das tubulações (kw), pelo método da tentativa e erro. Como ferramenta de modelagem foi utilizado o EPANET 2.0. A área de estudo desta pesquisa foi a rede de distribuição do bairro da Prata, localizada na zona de pressão B. Este bairro foi escolhido por apresentar rede diversificada, com tubulações de PVC e cimento amianto sendo sua rede de distribuição abastecida pelo reservatório R5 .Com os resultados obtidos foi possível concluir que o decaimento do cloro residual livre na rede de distribuição do bairro da Prata ocorre por reações no volume do escoamento, os valores de kb são elevados nos trechos de ponta de rede e a degradação mais intensa da concentração de cloro residual livre ocorre devido à estagnação da água nas tubulações. / The sanitary quality of the water is assured in the disinfection step of the treatment process. In Brazil Ordinance 2.914/2011 of the Ministry of Health, which regulates the procedures for controlling and monitoring water quality for human consumption and its potability water standard, recommends a minimum free chlorine residual of 0,2mgCl2/L, maximum of 2,0mgCl2/L and the maximum permitted value of 5,0mgCl2/L that must be ensured in the distribution network. Due to factors such as age of pipes, leaks, material, diameter and long distances between treatment systems and consumption centers, the recommended concentrations of free residual chlorine are not always maintained at all points in the water distribution network. This study aims to model the decay of free residual chlorine in the distribution network of the city of Campina Grande, Paraiba, by determining the residual chlorine concentration degradation kinetic free coefficients in the flow volume (kb) by the bottle test and in the wall of the pipes (kw) by the trial and error method. As a modeling tool was used EPANET 2.0. The study area of this research was the distribution network of the district of Prata, located in zone of pressure B. This local was chosen for presenting a diversified network, PVC pipes and asbestos cement being its distribution network supplied by the reservoir R5. With the results was concluded that the decay of the free residual chlorine in the distribution network of the district of Prata occurs by reactions in the volume of the flow, the values of kb are high in the sections of the network and the degradation more intense concentration of free chlorine residual occurs due to stagnation of water in the pipes.

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