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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.
41

[en] HALITE EFFECTS UPON HYDRATION AND MECHANICAL BEHAVIOR OF CEMENT PASTES FOR OIL WELL APPLICATIONS / [pt] EFEITO DE ROCHAS SALINAS NA HIDRATAÇÃO E COMPORTAMENTO MECÂNICO DE PASTAS CIMENTÍCIAS PARA POÇOS DE PETRÓLEO

CAROLINA BOCAIUVA LEITE DA SILVA 16 November 2016 (has links)
[pt] Na formulação e preparo de pastas cimentícias destinadas ao revestimento de poços de petróleo é imperativo que seja levado em conta o conjunto de condições associadas ao ambiente da prospecção. Esta tese tem por objetivo investigar a interação entre a halita e pastas cimentícias, no âmbito da exploração das reservas do pré-sal brasileiro, através da caracterização de propriedades químicas e mecânicas da pasta na presença de NaCl. A influência da temperatura, importante característica da camada em questão, também foi avaliada, a partir de duas condições de cura, a 23 graus Celsius e 60 graus Celsius. Sendo o sal artificial (para análises laboratoriais - PA) comumente empregado em substituição à halita na simulação dos efeitos da dissolução dos maciços salinos durante a cimentação, estes dois materiais foram utilizados comparativamente ao longo deste estudo. Os comportamentos observados em ensaios de compressão uniaxial foram similares, tendo sido demonstrado que, em baixas temperaturas, ocorrem ganho de resistência para adições salinas de até 10 porcento e perda de resistência para valores. Alterações nos mecanismos de hidratação e produtos formados são estudadas através de análises de difração de raios-x e termogravimetria. A partir destes testes, é possível a verificação da formação do Sal de Friedel, resultado da interação entre íons cloreto e fases aluminoferrosas do clínquer. Finalmente, é discutida a influência destas adições na reologia da pasta, ao se observar resultados divergentes para adições de sal PA e halita. / [en] When developing and designing cement pastes for oil well applications, proper attention should be given to the careful evaluation of the environment in which the prospection operations will take place. The work in hand presents an experimental investigation on the interaction between halite and cement pastes, meeting the continuous demand for research concerning the Brazilian pre-salt region. For this purpose, mechanical and chemical tests were carried out. Being a feature of major importance in pre salt activities, temperature effects were adressed through two different curing temperatures: 23 degrees Celsius and 60 degrees Celsius. Also, many authors use artificial salt as an alternative to halite when simulating the effects of salt rock dissolution. Therefore, both materials are used throughout the experimental program for comparison purposes. A similar unidirectional compressive behavior is noted for both materials. Gains in strength are noted at 23 degrees Celsius for both salts, to concentrations up to 10 percent by weight of water. On the other hand, higher concentrations or a higher curing temperature yield strength losses. Furthermore, hydration and microstructure changes are studied through x-ray diffraction and thermogravimetric analysis. Through these tests it is possible to detect the formation of Friedel s salt, as a result of the interaction between chloride ions and the aluminate and/or aluminoferrite phases of clinker. Finally, the influence of these additions on the rheology of the cement paste is discussed, as differences on the rheological behavior of these cement pastes are noted.
42

Estresse salino em plantas jovens de cana-deaçúcar: respostas bioquímicas e fisiológicas / Salt stress in young sugarcane plants: biochemical and physiological responses

Chiconato, Denise Aparecida [UNESP] 22 January 2016 (has links)
Submitted by DENISE APARECIDA CHICONATO (denise.ac@hotmail.com) on 2016-02-04T14:10:02Z No. of bitstreams: 1 Tese_Denise_Aparecida_Chiconato.pdf: 1322746 bytes, checksum: 5a673f4bca29c82501e188fb0ce8d28d (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-02-05T12:07:51Z (GMT) No. of bitstreams: 1 chiconato_da_dr_jabo.pdf: 1322746 bytes, checksum: 5a673f4bca29c82501e188fb0ce8d28d (MD5) / Made available in DSpace on 2016-02-05T12:07:51Z (GMT). No. of bitstreams: 1 chiconato_da_dr_jabo.pdf: 1322746 bytes, checksum: 5a673f4bca29c82501e188fb0ce8d28d (MD5) Previous issue date: 2016-01-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A cana-de-açúcar é uma cultura mundialmente importante. O Brasil é o maior produtor mundial de cana-de-açúcar e se destaca na comercialização e exportação de açúcar e etanol originados a partir desta cultura. Os diferentes estresses abióticos alteram negativamente o desenvolvimento das plantas e, entre os estresses, a salinidade de solos se apresenta pela grave redução de produtividade, sendo o principal fator estressante em regiões de clima árido e semiárido. Este trabalho objetivou verificar os efeitos do NaCl sobre o desenvolvimento de plantas jovens de cana-de-açúcar, cultivares SP 81-3250 e IAC 87-3396, mediante o estudo de variáveis fisiológicas-bioquímicas: (I) os osmoprotetores prolina, glicina betaína e sacarose, (II) a ocorrência de alterações nutricionais pela relação Na+/K+, (III) a peroxidação lipídica (IV) a influência do NaCl na atividade da enzima redutase do nitrato; (V) o efeito do estresse salino nas trocas gasosas; (VI) o crescimento de parte aérea e raízes das diferentes cultivares de cana-de-açúcar sob estresse salino. Para tanto, foram utilizadas quatro concentrações de NaCl (0, 40, 80 e 160 mM) e realizadas as seguintes avaliações: teores de Na+ e K+ nas folhas e raízes, os osmólitos compatíveis prolina, glicina betaína e sacarose, potencial hídrico, a peroxidação lipídica, atividade da enzima redutase do nitrato, trocas gasosas, clorofilas totais, rendimento quântico do FSII e crescimento de parte aérea e raiz aos 15 e 30 dias de desenvolvimento após aplicação do estresse. A partir dos resultados, observou-se maior suscetibilidade das plantas da cv. IAC 87-3396 pelo maior acúmulo de Na+ e relação Na+/K+, maior peroxidação lipídica pelo acúmulo de MDA e maior efeito negativo sobre as trocas gasosas. Ambas as cultivares apresentaram acúmulo de prolina sob estresse, porém, plantas da cv. SP 81-3250 apresentaram, além de mais rápido acúmulo deste aminoácido, menor peroxidação lipídica e crescimento superior. Sob estresse salino severo a cv. IAC 87-3396 apresenta maior suscetibilidade. / Sugarcane is a globally important crop. Brazil is the largest producer of sugarcane and stands out in the marketing and exportation of sugar and ethanol derived from this culture. The various abiotic stresses adversely change plant growth and between the stresses, soil salinity is presented by the severe reduction in productivity, it is the main stressor in arid and semi-arid climates. This study aimed to verify the effects of NaCl on the development of sugarcane young plants, SP 81- 3250 and IAC 87-3396 cultivars, through the study of physiological-biochemical variables: (I) the osmoprotectors proline, glycine betaine and sucrose, (II) the occurrence of nutritional changes the ratio Na+/K+ (III) lipid peroxidation (IV) effect of NaCl in the activity of nitrate reductase enzyme; (V) the effect of salt stress on gas exchange; (VI) the growth of shoots and roots of the sugarcane cultivars under salt stress. Thus, it was used four concentrations of NaCl (0, 40, 80 and 160 mM) and made the following assessments: Na+ and K+ accumulation in the leaves and roots, compatible osmolytes: proline, glycine betaine and sucrose, water potential, peroxidation lipid, activity of nitrate reductase enzyme, gas exchange, total chlorophyll, quantum yield of PSII and shoot and root growth at 15 and 30 days of development after stress application. The results showed higher susceptibility of the cv. IAC 87-3396 by higher accumulation of Na+ and Na+/K+ ratio, increase in lipid peroxidation by MDA accumulation and greater negative effect on gas exchange. Both cultivars showed proline accumulation under stress, however, the cv. SP 81- 3250 showed in addition faster accumulation of this amino acid, reduced lipid peroxidation and higher growth. Under severe salt stress cv. IAC 87-3396 is more susceptible.
43

Influência de diferentes doses de salinidade e níveis de água na produção de cenoura

Panazzolo, Francieli [UNESP] 23 February 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:26:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-23Bitstream added on 2014-06-13T19:55:06Z : No. of bitstreams: 1 panazzolo_f_me_botfca.pdf: 695410 bytes, checksum: 68a4f2852f522f08b7912faf2c61757b (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / A cenoura (Daucus carota L.) é uma hortaliça amplamente empregada na alimentação do brasileiro, constituindo uma rica fonte de cálcio e vitamina A, de fácil digestão e baixo teor de calorias. A cultivar Brasília foi desenvolvido para ser cultivada no verão, apresentando resistência ao calor, com produtividade média de 30 t ha-1 e ciclo médio de 85 a 100 dias. O presente trabalho teve por objetivo avaliar os possíveis efeitos do estresse hídrico e salino no crescimento e nas características morfológicas da cultivar Brasília. O experimento foi conduzido em casa de vegetação, no Departamento de Engenharia Rural da Faculdade de Ciências Agronômicas, Botucatu–SP, nos meses de setembro de 2009 e janeiro de 2010. O manejo hídrico foi estabelecido com base no potencial de água no solo e foram determinados três níveis de água (-0,01; -0,04 e -0,06 MPa), fazendo-se a reposição de água evapotranspirada por pesagem dos vasos. Foram utilizadas quatro doses de cloreto de sódio (1,41; 2,50; 4,50 e 6,45 dS m-1). O ensaio constituiu-se de um fatorial 3x4 (três níveis de água x quatro doses de salinidade). Os parâmetros morfológicos observados foram: altura da parte aérea, massas fresca e seca de parte aérea; massas fresca e seca da parte radicular (bulbo), comprimento da parte radicular (bulbo), diâmetro da parte radicular (bulbo) e produtividade. Foram realizadas três avaliações morfológicas durante os 100 dias após plantio e avaliações diárias de sobrevivência. A análise estatística dos dados foi feita pela análise de variância e teste de Tukey com 5% de probabilidade. Os resultados nas condições deste experimento permitiram as seguintes conclusões: Não foram observadas diferenças significativas... / The carrot (Daucus carota L.) is a vegetable widely used in the Brazilian diet, constituting a rich source of calcium and vitamin A, digestible and low in calories. The cultivar Brasilia was designed to be cultivated in summer, showing resistance to heat, with an average yield of 30 t ha-1 and average cycle from 85 to 100 days. This study aimed to evaluate the possible effects of water stress and salinity on growth and morphological characteristics of the Brasilia cultivar. The experiment was conducted in a greenhouse at the Department of Agricultural Engineering, Faculty of Agronomic Sciences, Botucatu-SP, on September 2009 until January 2010. The water management was based on soil water potential determined and three water levels (-0.01, -0.04 and -0.06 MPa), but with the replacement of water transpired by weighing the pots. We used four doses of sodium chloride (1.41, 2.50, 4.50 and 6.45 dS m-1). The test consisted of a 3x4 factorial (three levels of water salinity x four doses). The morphological parameters were: shoot height, fresh and dry shoot, fresh and dry weight of roots (bulb), length of roots (bulb), diameter of the root (bulb) and productivity. They performed three morphological evaluations during the 100 days after planting and daily assessments of survival. The statistical analysis was performed by ANOVA and Tukey test at 5% probability. The results allowed the following conclusions: there are not observed significant differences on plant development subjected to different minmum soil water potentials (Ψs) = -0,01; -0,04 e -0,06 MPa; the treatments that did not received saline doses showed higher development in relation to aereal part height and bulb length on three available periods (60, 80 e 100 days after planting); the applied saline doses (1,41; 2,50; 4,50 e 6,45 dS m-1 NaCl) did not statistically affect plant development in relation to fresh and dry of aereal... (Complete abstract click electronic access below)
44

Uso intrapleural de solução de cloreto de sódio 0,9%, adicionada ou não de dexametasona, na prevenção de aderências pulmonares após toracotomia intercostal em cães

Santos, Rogerio Rodrigues [UNESP] 27 January 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:23:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-01-27Bitstream added on 2014-06-13T20:50:56Z : No. of bitstreams: 1 santos_rr_me_jabo.pdf: 474297 bytes, checksum: d647e5060a5a64060b7305688ac2fc49 (MD5) / As aderências pulmonares em cães são uma sequela comum, após intervenção cirúrgica, prejudicando eventuais reintervenções. Neste estudo, pretendeu-se verificar, em cães, a eficiência da solução de cloreto de sódio 0,9%, adicionada ou não com dexametasona, na prevenção de aderências após toracotomia intercostal, Para isso, foram utilizados 15 cães, separados em três grupos de cinco, denominados A, B e C e submetidos a toracotomia no quinto espaço intercostal esquerdo. Nos cães do grupo A, foi feita somente a toracotomia e a toracorrafia; no grupo B foram realizadas a toracotomia, a toracorrafia e a injeção na cavidade pleural de 10ml de solução de cloreto de sódio a 0,9% associada com 1mg kg-1 de dexametasona. No grupo C, além da toracotomia e toracorrafia foram injetados na cavidade pleural 10ml kg-1 de solução de cloreto de sódio a 0,9%. Após 15 dias da toracotomia com os três tratamentos foi efetuada a toracoscopia transdiafragmática para se determinar a presença e o escore de aderências entre o pulmão e a parede costal. Os resultados demonstraram presença de aderências na maioria dos animais do grupo A e reduzida a nenhuma aderência nos demais grupos. Na avaliação estatística, foi aplicado o teste quiquadrado, com nível de significância de 5% (P≤0,05). O uso de solução de cloreto de sódio a 0,9% adicionada ou não com dexametasona no espaço pleural reduz ou evita aderências pulmonares após a toracotomia intercostal / Pulmonary adhesions in dogs are a common sequela after surgical intervention, undermining any interventions. This study aimed at determining, in dogs, the efficacy of sodium chloride solution 0.9% with or without dexamethasone in order to prevent adhesions after intercostal thoracotomy. Fifteen dogs were separated into three groups of five animals, A, B and C and underwent thoracotomy in the fifth left intercostal space. In the dogs of Group A were performed only a thoracotomy and thoracorraphy; in the dogs of group B, were performed a thoracotomy, thoracorraphy and injection into the pleural cavity of 10ml of isotonic sodium chloride and 1mg kg-1 of dexamethasone; In the dogs of group C, were performed the thoracotomy thoracorraphy and injected into the pleural cavity 10ml kg-1 of isotonic sodium chloride. After 15 days of thoracotomy, was performed transdiaphragmatic thoracocospy to determine the presence and score of adhesions between the lung and chest wall. The results demonstrated the presence of adhesions in the majority of group A and reduced or no adhesions in the other groups. For statistical evaluation, we applied the chi-square test with significance level of 5% (P≤0.05). The sodium chloride solution 0.9% with or without dexamethasone into the pleural space prevented or reduced lung adhesions after intercostal thoracotomy
45

Uso intrapleural de solução de cloreto de sódio 0,9%, adicionada ou não de dexametasona, na prevenção de aderências pulmonares após toracotomia intercostal em cães /

Santos, Rogerio Rodrigues. January 2011 (has links)
Resumo: As aderências pulmonares em cães são uma sequela comum, após intervenção cirúrgica, prejudicando eventuais reintervenções. Neste estudo, pretendeu-se verificar, em cães, a eficiência da solução de cloreto de sódio 0,9%, adicionada ou não com dexametasona, na prevenção de aderências após toracotomia intercostal, Para isso, foram utilizados 15 cães, separados em três grupos de cinco, denominados A, B e C e submetidos a toracotomia no quinto espaço intercostal esquerdo. Nos cães do grupo A, foi feita somente a toracotomia e a toracorrafia; no grupo B foram realizadas a toracotomia, a toracorrafia e a injeção na cavidade pleural de 10ml de solução de cloreto de sódio a 0,9% associada com 1mg kg-1 de dexametasona. No grupo C, além da toracotomia e toracorrafia foram injetados na cavidade pleural 10ml kg-1 de solução de cloreto de sódio a 0,9%. Após 15 dias da toracotomia com os três tratamentos foi efetuada a toracoscopia transdiafragmática para se determinar a presença e o escore de aderências entre o pulmão e a parede costal. Os resultados demonstraram presença de aderências na maioria dos animais do grupo A e reduzida a nenhuma aderência nos demais grupos. Na avaliação estatística, foi aplicado o teste quiquadrado, com nível de significância de 5% (P≤0,05). O uso de solução de cloreto de sódio a 0,9% adicionada ou não com dexametasona no espaço pleural reduz ou evita aderências pulmonares após a toracotomia intercostal / Abstract: Pulmonary adhesions in dogs are a common sequela after surgical intervention, undermining any interventions. This study aimed at determining, in dogs, the efficacy of sodium chloride solution 0.9% with or without dexamethasone in order to prevent adhesions after intercostal thoracotomy. Fifteen dogs were separated into three groups of five animals, A, B and C and underwent thoracotomy in the fifth left intercostal space. In the dogs of Group A were performed only a thoracotomy and thoracorraphy; in the dogs of group B, were performed a thoracotomy, thoracorraphy and injection into the pleural cavity of 10ml of isotonic sodium chloride and 1mg kg-1 of dexamethasone; In the dogs of group C, were performed the thoracotomy thoracorraphy and injected into the pleural cavity 10ml kg-1 of isotonic sodium chloride. After 15 days of thoracotomy, was performed transdiaphragmatic thoracocospy to determine the presence and score of adhesions between the lung and chest wall. The results demonstrated the presence of adhesions in the majority of group A and reduced or no adhesions in the other groups. For statistical evaluation, we applied the chi-square test with significance level of 5% (P≤0.05). The sodium chloride solution 0.9% with or without dexamethasone into the pleural space prevented or reduced lung adhesions after intercostal thoracotomy / Orientador: José Antônio Marques / Coorientador: Alceu Gaspar Raiser / Banca: Silvana Martinez Baraldi Artoni / Banca: Richard da Rocha Filgueiras / Mestre
46

Determinação do teor de NaCl, Glicose e KCI em medicamentos injetáveis por fotometria usando exploração do efeito Schlieren em Sistemas FIA e PLS1 / Determination of NaCl, KCl and Glucose Content in Injectable Pharmaceuticals by Photometry Exploring the Schlieren Effect in FIA Systems and PLS1

Diniz, Paulo Henrique Gonçalves Dias 01 October 2010 (has links)
Made available in DSpace on 2015-05-14T13:21:52Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2728710 bytes, checksum: 6517b3a8e30d4a561eb90e4be9c69916 (MD5) Previous issue date: 2010-10-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This study evaluated using the Schlieren effect in FIA systems as a new strategy to determine the amounts of sodium chloride, potassium chloride and glucose, each respectively in intravenous drugs. The proposed methodology was based on the difference between the refractive indices of sample zones and the carrier stream. With this perspective, photometric detection was used based on an LED and a phototransistor to investigate the different analytical profiles related to the Schlieren effect in low flow rate conditions. Adjustment studies of the parameters and flow settings (which were most suitable to exploit Schlieren profiles), were performed. The proposed methodology generates a large amount of chemical information and therefore requires the use of chemometric tools. Data evaluation was performed with the application of a partial least squares regression (PLS1), employing the standard solutions of each analyte to construct and validate the models. The models were then used to predict the content of each analyte in their real samples. The results demonstrated the predictive ability of the constructed PLS1 models, and the predicted concentration values were in agreement with the reference values, with 95% of confidence. The main advantages of using the Schlieren effect in the chemical analysis is that no reagent is employed, low volumes of samples are used and no expensive radiation detectors are used. / Neste trabalho foi avaliada a exploração do efeito Schlieren em sistemas FIA para a implementação de uma nova estratégia para determinar o teor de cloreto de sódio, cloreto de potássio e glicose em amostras de soro fisiológico, KCl injetável e soro glicosado, respectivamente. A metodologia proposta se baseia na diferença entre os índices de refração das zonas da amostra e do fluido carregador. Nesta perspectiva, foi empregada detecção fotométrica baseada em LED e fototransistor para investigar diferentes perfis analíticos associados ao efeito Schlieren em condições de baixa vazão. Estudos para ajuste dos parâmetros e configurações de fluxo mais adequados nos quais os perfis Schlieren podem ser explorados foram realizados. A metodologia proposta gera uma grande quantidade de informações químicas e, por isso, requer a utilização de ferramentas quimiométricas. A avaliação dos resultados foi realizada com a aplicação da regressão por mínimos quadrados parciais (PLS1), a qual empregou as soluções padrão de cada analito para construção e validação dos modelos. Em seguida, os modelos construídos foram utilizados para a previsão do teor de cada analito em suas respectivas amostras reais. Os resultados obtidos demonstraram a boa capacidade preditiva dos modelos PLS1 construídos, pois os valores das concentrações previstos pelos modelos foram concordantes com os valores de referência, no nível de 95% de confiança. As maiores vantagens da exploração do efeito Schlieren na análise química são que nenhum reagente é empregado, que utiliza baixo volume de amostras e que não emprega caros detectores de radiação.
47

Parametric Studies of Picosecond Laser-Induced Breakdown in Fused Quartz and NaCl

Williams, William Ely 12 1900 (has links)
Bulk laser-induced breakdown and self-focusing in single samples of fused quartz and NaCl were examined using picosecond optical pulses at 1.0 ym and 0.5 ym. The results of three separate but related experiments are reported. First the nonlinear index of refraction, n2, of each of the test materials is measured near the respective damage thresholds of the samples. The values of 1*2 were determined by detecting beam distortions in the far field, transmitted laser beam profile caused by the irradiance dependent index of refraction. The experimental traces were compared to theoretical beam profiles generated by a nonlinear propagation code and n2 was extracted from the resulting fits.
48

Experimentální analýza vlivu chloridových solí v poli neutronů různých energií / Experimental analysis focused on the effect of chloride salt on neutron flux with different energy levels

Slančík, Tomáš January 2019 (has links)
Master’s thesis focuses on the history and current progress in research of molten salt reactors around the world, with an emphasis placed on the properties of molten salts and the problems associated with their use. In relation to the practical part, one chapter is devoted to the creation of input file in the MCNP software. The practical part deals with neutron activation analysis of graphite prism experiment, which is filled with powder NaCl salt. This experiment is focused on the effect of salt on neutron flux with different energy levels. The whole problem was also simulated in the MCNP environment along with the experiment. At the end of the thesis, the individual methods are compared and evaluated.
49

Studium reverzibilní adsorpce nukleových kyselin na magnetických nosičích / Study of reversible adsorption of nucleid acids on magnetic carriers

Šálek, Petr January 2008 (has links)
Reversible adsorption of nucleid acids on magnetic carriers was studied in this diploma thesis. Magnetic P(HEMA-co­-GMA) microspheres and magnetic glass particles were used. The aim of the study was to isolate DNA in suitable quality for polymerase chain reaction (PCR). Adsorption of DNA on magnetic carriers was achieved after DNA condensation by PEG and NaCl in separation mixture. PEGs of various molecular weight (600 and 6000 g/mol) and different concentrations of PEG in separation mixture (4, 8, 12, 16%) were used. Quantity of eluted DNA incerased with molecular weight and concentration of PEG in separation mixtures. Optimized experimental conditions were applied for the separation of DNA from chicken erythrocytes, purified DNA, DNA in crude lysates of bacterial cells of Lactobacillus paracasei ssp. paracasei CCDM 211/06 and from real samples (liquid dairy products, hard cheese). The presence of target DNA in eluates was tested using genus specific PCR (genus Lactobacillus) or species specific PCR (species Bifidobacterium longum) Aqueous two-phase system (liquid-liquid) was used for separation of DNA from real symplex, too. At first the condiotions aqueous two-phase systém creation were studied. It was created by 16% PEG of various molecular weight (600, 6000 g/mol) and by various concentration of ammonium sulphate. Reversible DNA adsorption on carboxyl group-containing magnetic nonporous P(HEMA-co-EDMA) microspheres for the isolation PCR-ready DNA from liquid dairy products containing PCR inhibitors was studied, too. The quality of isolated DNA was checked by PCR amplification.The presumption on the elimination of PCR inhibitors from DNA samples was confirmed.
50

Ammonia Removal from Mining Wastewater by Ion-Exchange Regenerated by Chlorine Solutions

Zhang, Tianguang 17 January 2022 (has links)
The mining industry is a significant contributor to the Canadian economy. However, the mining activities can be detrimental to the environment due to the release of pollutants. Ammonia is one of the noxious and toxic contaminants associated with mining, ammonia contamination is created by the oxidizing agent in explosives. The explosives impacted mining wastewater (EIMWW) usually contains ammonia and other metal ions. The ammonia in EIMWW could harm the aquatic environment by the depletion of oxygen and its lethal toxicity to aquatic organisms. Before release to environment, EIMWW needs to be treated with an easy-to-operate method for ammonia removal at the remote mining sites. Ion-exchange (IE) with zeolite is an effective method for ammonia removal that is easy-to-operate, is not significantly impacted by cold temperature or toxicity effects. However, the traditional IE regeneration approach of using high concentration NaCl solutions creates a secondary polluting stream. Chlorine regeneration of ammonia-loaded zeolite appears to be a promising option, an evaluation of this option is the main topic of this thesis. This thesis includes three initiatives. The first is a set of multi-cycle batch loading-regeneration tests to assess the viability of ammonia removal with a commercial zeolite (SIR-600) for the treatment of a synthetic EIMWW (containing total ammonia nitrogen (TAN), K, and Ca) and to examine the performance of different ion-exchange regeneration solutions. The long-term TAN uptake of SIR-600 regenerated using a NaOCl (100 mg free Cl2/L) solution was 0.24 meq/g, which was approximately 20% lower than that after a NaCl regeneration. However, chlorine regeneration is promising because the selectivity of SIR-600 for TAN over Ca and K increased after the chlorine regeneration. To simulate recycling of the NaOCl regenerants, K and Ca were added to the NaOCl solution, it did not substantially affect the subsequent SIR-600’s ion uptake. This initiative represents a significant contribution since the earlier studies into chlorine regeneration did not investigate the impact of competing ions. The second initiative addressed concerns regarding the long-term integrity of SIR-600 arising from its exposure to high chlorine concentrations during the regeneration. The five-week long chlorine batch exposure tests with solutions of up to 1000 mg free Cl2/L showed that chlorine exposure did not significantly affect the SIR-600’s characteristics in terms of particle size distribution, surface area, FTIR spectra and ion uptake. Thus, SIR-600 has the potential for long-term use in field applications. The final initiative evaluated the feasibility of chlorine regeneration for continuous flow IE column systems used for ammonia removal from a synthetic EIMWW. Continuous flow column systems are important because these are the standard IE units used in full-scale applications. Multi-cycle column loading-regeneration tests were performed to compare the zeolite performance using a NaOCl (1000 ppm as free Cl2) solution with that using a 5% NaCl regeneration. The influence of loading duration was also assessed. The use of 6-hr loading cycles were shown to be preferable to 23-hr loading cycles because it had lower effluent concentrations and they could achieve higher overall TAN mass removals per unit time. After three operational cycles, the SIR-600 had similar TAN uptake performances (0.21 meq/g Vs. 0.21 meq/g) after NaOCl regeneration and after salt (NaCl) regeneration. This is in contrast to the lower TAN uptakes for the NaOCl regeneration in the batch tests, this indicates that batch tests are not always representative of full-scale applications. Compared to NaCl regenerated SIR-600, SIR-600 after NaOCl regeneration had a higher preference for TAN over Ca and K, which makes this type of regeneration very promising. Its only apparent limitation is that the NaOCl regeneration required a longer duration. During the NaOCl regeneration, the main mechanism appears to be the oxidation of ammonia to nitrogen gas and hydrogen ions, however the Na in the NaOCl solution also seems to have a role in the regeneration.

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