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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.
131

Cleaner Chrome Tanning: Technology of low-chrome tanning without salt, pickling and short procedure

Jianxun, Luo, Yanjuan, Feng, Hewei, Ma 26 June 2019 (has links)
Content: Tannery effluent with high salinity and chromium have a serious environmental impact. The traditional chrome tannage that involved the use of sodium chloride, acid and chromium is one of the main origins of salt and chromium pollution. In this study, a non-pickling, low-chrome tanning technology was developed. The novel Chrome-free agent SL can be directly employed to tan bated cattle pelts and the wet white was obtained. Then the shaved wet white was pre-treated by Poly-carboxylate auxiliary agent and tanned by chrome powder. It was tested that the shrinkage temperature of the wet white, the initial pH of chrome tanning, the consumption of chrome powder, the shrinkage temperature of the chrome-tanned leather, the content of Cr2O3 in effluent, the absorption of chromium and the other properties of the chrome-tanned leather. It was found that the shrinkage temperature of the wet white tanned by SL reached over 80oC, the optimal consumption of Poly-carboxylate auxiliary agent was 2wt% based on the weight of the shaved wet white, the better low-chrome tanning conditions were that the wet white was tanned by 4wt% chromium powder for 150~180min at room temperature when the initial pH value was 3.5. The next processes were same as traditional chrome tannage. Meanwhile, the shrinkage temperature of the leather tanned by the low-chrome tannage reached more than 95oC, the absorption of chromium was 96%, the content of Cr2O3 in the effluent was under 200mg/L. For the low-chrome tanned leather, the absorption of dyestuff, fat-liquor reached 99.5%, 82.5% respectively. Compared with the traditional chrome tanned process, not only the conventional pickling process was eliminated, the process was been shorten and reduce the pollution of sodium chloride, but it can reduce 50% of the consumption of Chrome powder, improve the absorption of chromium and can reduce content of Cr2O3 in effluent. Take-Away: 1. LUO JIAN-XUN, LI JING, LIAO XUE-PIN,etc.Cleaner Chrome Tanning – A Non-Pickling Process Using an Aliphatic Aldehyde as Pre-tanning Agent. J. Soc. Leather. Technol.Chem. 2012,96 (1):21-26. 2.LUO JIAN-XUN,FENG YANJUAN.Cleaner Processing of Bovine Wet-white: Synthesis and Application of a Novel Chrome-free Tanning Agent Based on an Amphoteric Organic Compound. J. Soc. Leather. Technol.Chem. 2015,99 (4):190-195. 3.XU JIA-LI, LUO JIAN-XUN.Synthesis and application of a polycarboxylate auxiliary agent. China Leather.2017,46(3):35-41.
132

Leather in Late Iron Age Scandinavia : From elk-traps to cheese-glue / Läder i den sena järnålderns Skandinavien : Från älgfällor till ostlim

Carlson, Stella January 2021 (has links)
Leather is a material that throughout history has been very important for humankind. Up until recently is has often however, together with other organic materials, not been given the attention it might deserve. This essay investigates how leather from the Late Iron Age in Scandinavia can be studied, if specialisation within leather related crafts can be identified and what this can tell us about how crafting skills were spread in a society. First a broader analysis is made of related crafts in the Late Iron Age, which is then put into relation to three chosen Vendel Age graves from the Valsgärde burial ground. Both leather production through hunting and tanning, and item production techniques like for example sewing and scabbard making are reviewed. Problems with preservation are discussed and possible alternative ways to study the subject are explored. The essay concludes that leather crafting included many techniques spread in society, practiced by common people. Still, several explicit specialisations also existed, which created high-quality leather products. Finally, suggestions for future research are made. / Läder har som material varit mycket viktigt genom hela den mänskliga historien. Fram tills nyligen har det, tillsammans med andra organiska material, dock ofta inte fått den uppmärksamhet det kanske förtjänar. Den här uppsatsen undersöker hur läder från den sena järnålderns Skandinavien kan studeras, om specialisering inom läderhantverk kan identifieras och vad detta kan berätta för oss om hur hantverkskompetens var spritt i ett samhälle. Först görs en bredare analys av relaterade hantverk under den sena järnåldern, vilket sedan sätts i relation till tre vendeltida gravar från gravfältet i Valsgärde. Både produktion av läder genom jakt och garvning, och tekniker för produktion av föremål såsom sömnad och tillverkning av svärdsskidor granskas. Problematik med bevarandeförhållanden diskuteras och alternativa sätt att studera ämnet utforskas. Slutsatserna av uppsatsen är att läderhantverk inkluderade många olika hantverkstekniker, som var spridda i hela samhället och praktiserades av vanligt folk. Flertalet explicita specialiseringar existerade dock också, vilket gav upphov till högkvalitativa läderprodukter. Slutligen ges förslag till framtida forskning.
133

Engaging Moms on Teen Indoor Tanning Through Social Media: Protocol of a Randomized Controlled Trial

Pagoto, Sherry L., Baker, Katie, Griffith, Julia, Oleski, Jessica L., Palumbo, Ashley, Walkosz, Barbara, Hillhouse, Joel J., Henry, Kimberly L., Buller, David 01 January 2016 (has links)
Background: Indoor tanning elevates the risk for melanoma, which is now the most common cancer in US women aged 25-29. Public policies restricting access to indoor tanning by minors to reduce melanoma morbidity and mortality in teens are emerging. In the United States, the most common policy restricting indoor tanning in minors involves parents providing either written or in person consent for the minor to purchase a tanning visit. The effectiveness of this policy relies on parents being properly educated about the harms of indoor tanning to their children. Objective: This randomized controlled trial will test the efficacy of a Facebook-delivered health communication intervention targeting mothers of teenage girls. The intervention will use health communication and behavioral modification strategies to reduce mothers’ permissiveness regarding their teenage daughters’ use of indoor tanning relative to an attention-control condition with the ultimate goal of reducing indoor tanning in both daughters and mothers. Methods: The study is a 12-month randomized controlled trial comparing 2 conditions: an attention control Facebook private group where content will be relevant to teen health with 25% focused on prescription drug abuse, a topic unrelated to tanning; and the intervention condition will enter participants into a Facebook private group where 25% of the teen health content will be focused on indoor tanning. A cohort of 2000 mother-teen daughter dyads will be recruited to participate in this study. Only mothers will participate in the Facebook groups. Both mothers and daughters will complete measures at baseline, end of intervention (1-year) and 6 months post-intervention. Primary outcomes include mothers’ permissiveness regarding their teenage daughters’ use of indoor tanning, teenage daughters’ perception of their mothers’ permissiveness, and indoor tanning by both mothers and daughters. Results: The first dyad was enrolled on March 31, 2016, and we anticipate completing this study by October 2019. Conclusions: This trial will deliver social media content grounded in theory and will test it in a randomized design with state-of-the-art measures. This will contribute much needed insights on how to employ social media for health behavior change and disease prevention both for indoor tanning and other health risk behaviors and inform future social media efforts by public health and health care organizations. ClinicalTrial: Clinicaltrials.gov NCT02835807; https://clinicaltrials.gov/ct2/show/NCT02835807 (Archived by WebCite at http://www.webcitation.org/6mDMICcCE).
134

Theory-Driven Longitudinal Study Exploring Indoor Tanning Initiation in Teens Using a Person-Centered Approach

Hillhouse, Joel J., Turrisi, Rob, Cleveland, Michael J., Scaglione, Nichole M., Baker, Katie, Florence, L. Carter 01 February 2016 (has links)
Background Younger indoor tanning initiation leads to greater melanoma risk due to more frequent and persistent behavior. Despite this, there are no published studies exploring the predictors of indoor tanning initiation in teen populations. Purpose This longitudinal study uses latent profile analysis to examine indoor tanning initiation in indoor tanning risk subgroups from a national sample of female adolescents. Methods Latent profile analysis used indoor tanning beliefs and perceptions to identify indoor tanning initiation risk subgroups. The teens in each subgroup were reassessed on indoor tanning initiation after a year. Results Three subgroups were identified: a low risk, anti-tanning subgroup (18.6 %) characterized by low scores on positive indoor tanning belief scales and high scores on beliefs about indoor tanning dangers; a moderate risk aware social tanner subgroup (47.2 %) characterized by high scores on positive indoor tanning belief scales but also high scores on beliefs about indoor tanning dangers; and a high risk risky relaxation tanner subgroup (34.2 %) characterized by high scores on positive indoor tanning belief scales and low scores on beliefs about indoor tanning dangers. Teens in the aware social tanner and risky relaxation tanner subgroups were significantly more likely to initiate indoor tanning in the following year. Conclusions These findings highlight the need to identify teens at risk for indoor tanning initiation and develop tailored interventions that will move them to the lowest risk subgroup. Subgroup correlates suggest parent and peer-based interventions may be successful.
135

A Web-Based Intervention to Reduce Indoor Tanning Motivations in Adolescents: a Randomized Controlled Trial

Hillhouse, Joel J., Turrisi, Rob, Scaglione, Nichole M., Cleveland, Michael J., Baker, Katie, Florence, L. Carter 01 February 2017 (has links)
Youthful indoor tanning as few as ten sessions can increase the risk of melanoma by two to four times with each additional session adding another 2 % to the risk. Recent research estimates that indoor tanning can be linked to approximately 450,000 cases of skin cancer annually in the USA, Europe, and Australia. Despite these risks, indoor tanning remains popular with adolescents. This study tested the efficacy of a web-based skin cancer prevention intervention designed to reduce indoor tanning motivations in adolescent females. A nationally representative sample of 443 female teens was enrolled from an online panel into a two-arm, parallel group design, randomized controlled trial. Treatment participants received an appearance-focused intervention grounded in established health behavior change models. Controls viewed a teen alcohol prevention website. Outcome variables included willingness and intentions to indoor tan, willingness to sunless tan, and measures of indoor tanning attitudes and beliefs. The intervention decreased willingness and intentions to indoor tan and increased sunless tanning willingness relative to controls. We also examined indirect mechanisms of change through intervening variables (e.g., indoor tanning attitudes, norms, positive and negative expectancies) using the product of coefficient approach. The web-based intervention demonstrated efficacy in changing adolescent indoor tanning motivations and improving their orientation toward healthier alternatives. Results from the intervening variable analyses give guidance to future adolescent skin cancer prevention interventions.
136

Cinética dos contaminantes e otimização da estabilização por solidificação de lodo de curtume.

GUIMARÃES, Adriana Valéria Arruda. 16 August 2018 (has links)
Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-08-16T16:52:01Z No. of bitstreams: 1 ADRIANA VALÉRIA ARRUDA GUIMARÃES – TESE (PPGEQ) 2017.pdf: 2201140 bytes, checksum: 097db96ed09bdde84b6831586b738b25 (MD5) / Made available in DSpace on 2018-08-16T16:52:01Z (GMT). No. of bitstreams: 1 ADRIANA VALÉRIA ARRUDA GUIMARÃES – TESE (PPGEQ) 2017.pdf: 2201140 bytes, checksum: 097db96ed09bdde84b6831586b738b25 (MD5) Previous issue date: 2017-02-24 / Capes / O lodo de curtume é classificado como sendo resíduo sólido perigoso - Classe I. Desse modo, compromete o meio ambiente em virtude da presença de cromo (Cr3+), sulfetos (S2-) e elevada matéria orgânica. Nesta pesquisa, o lodo de curtume foi submetido ao processo de estabilização por solidificação, tendo como objetivos determinar a velocidade de decaimento cinético dos contaminantes além de otimizar o processo de estabilização por solidificação do lodo de curtume. O planejamento experimental realizado foi o fatorial ao acaso, com dois fatores e duas repetições, resultando em 18 tratamentos os quais utilizaram como fatores porcentagem de lodo de curtume (5%, 15% e 25%) e tempo de cura (7, 28 e 90 dias). Foi realizada a avaliação do material estabilizado por solidificação com os critérios de integridade/durabilidade e imobilização dos contaminantes. A Análise de Variância possibilitou obter a otimização do processo de tratamento do lodo de curtume, o balanço de massa e a eficiência de retenção dos contaminantes do material estabilizado. Finalmente, foi realizada a cinética dos contaminantes levando em consideração o tempo de cura e a porcentagem. O presente trabalho de tese expõe três importantes contribuições cientificas que o diferencia das demais pesquisas desenvolvidas tratando lodo de curtume. A primeira está voltada à otimização do processo de estabilização por solidificação, no qual foi encontrado o ponto ótimo entre o tempo de cura e a porcentagem de lodo de curtume. A segunda encontra-se relacionado à velocidade de decaimento cinético dos contaminantes. E finalmente, a terceira está relacionada ao balanço de massa e a eficiência do processo de E/S dos contaminantes presentes no lodo de curtume. Como resultado desse estudo verificou-se que, a otimização das respostas foi a maneira de minimizar e/ou maximizar as variáveis respostas do processo de E/S, conseguido com menor tempo de cura e menor porcentagem de lodo. De acordo com a função desejável todos os tratamentos foram aprovados nos ensaios de integridade/durabilidade e imobilização dos contaminantes, fazendo a conversão da Classe I (perigoso) para Classe II (não perigoso). Os parâmetros relacionados à integridade durabilidade obtiveram sua otimização com pontos ótimos distintos. As melhores respostas para os parâmetros ambientais nos extratos lixiviado e solubilizado foram atribuídos aos tratamentos combinados com o menor tempo de cura e a menor porcentagem de lodo de curtume. A pesquisa permitiu concluir que foi possível determinar a cinética dos contaminantes do lodo de curtume quanto à otimização do processo de E/S. Com isso, a redução na velocidade de decaimento cinético dos contaminantes ambientais, nos extratos lixiviado e solubilizado, foi atribuída aos tratamentos combinados com a menor porcentagem de lodo de curtume e tempo de cura variado. O processo de estabilização por solidificação tratando o lodo de curtume foi eficiente, uma vez que promoveu atenuação dos contaminantes convertendo da classe perigosa para não perigosa. / The tannery sludge is classified as a Class I – hazardous solid residue. It compromises the environment due to the presence of chromium (Cr3+), sulfides (S2-) and high amounts of organic matter. In this research, the tanning sludge was subjected to a solidification stabilization process, aiming to determine the kinetic decay rate of the contaminants and to optimize the stabilization process by solidification of the tannery sludge. The experimental design comprised two factors and two replicates, resulting in 18 treatments, which used percentage of tannery sludge (5%, 15% and 25%) and curing time (7, 28 and 90 days) as variables. An evaluation of the material stabilized by solidification was carried out with the criteria of integrity/durability and immobilization of contaminants. The variance analysis allowed us to obtain a process optimization of the tannery sludge treatment, the mass balance and a retention efficiency of the stabilized material contaminants. Finally, the contaminants kinetics were analyzed taking into account the tannering time and percentage. The present work is different from previous ones because it presents three important scientific contributions regarding the tannery sludge treatment. The first one is focused on the optimization of the solidification stabilization process, in which was found an ideal balance between tannering time and percentage. The second is related to the rate of the contaminants kinetic decay. The third one is related to the mass balance and an edition of the S/S process of the contaminants present within the tanning sludge. As a result of the study it was found that, an optimization of the responses to minimize and/or maximize as variables of the S/S process responses, achieved with shorter cure duration and lower sludge percentage. According to a desirable function all the treatments were approved in the integrity/durability tests and immobilization of the contaminants, converting it from a Class I (dangerous) to a Class II (non-hazardous) residue. The parameters related to the durability and integrity obtained their optimization with different optimum points. The best responses to the environmental control in the leached and solubilized extracts were attributed to the combined treatments with the lowest tannering rate and percentage of tannery sludge. The research concluded that it was possible to determine the kinetics of tannery sludge contaminants in the optimization of the S/S process. Thus, a reduction in the kinetic detoxification rate of the environmental contaminants in the leached and solubilized extracts was attributed to treatments combined with a smaller percentage of tannery sludge and varied tannering time. The solidification stabilization process used to treat the tannery sludge was efficient as it promoted the attenuation of contaminants converting it from a hazardous to a non-hazardous residue.
137

Potencialidade dos extratos tânicos das espécies angico vermelho, jurema preta e jurema vermelha no curtimento de peles caprinas. / Potential of tannin extracts of the angico-vermelho, jurema-preta and jurema-vermelha species in the goat leather tanning.

LIMA, Carlos Roberto de. 18 September 2018 (has links)
Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-09-18T14:43:37Z No. of bitstreams: 1 CARLOS ROBERTO DE LIMA - TESE (PPGRN) 2011.pdf: 6096425 bytes, checksum: e79260d5348e29924543c57235a532a5 (MD5) / Made available in DSpace on 2018-09-18T14:43:37Z (GMT). No. of bitstreams: 1 CARLOS ROBERTO DE LIMA - TESE (PPGRN) 2011.pdf: 6096425 bytes, checksum: e79260d5348e29924543c57235a532a5 (MD5) Previous issue date: 2011-02-25 / CNPq / Nas últimas décadas, com o crescimento populacional e os avanços tecnológicos ocorridos, houve aumento significativo da pressão sobre a flora nativa de muitas regiões, em diferentes partes do mundo, inclusive na região semi-árida do Brasil (Caatinga), nas mais variadas formas, destacando-se a produção de lenha e de carvão vegetal e, utilização das cascas do angico-vermelho (Anadenanthera colubrina (Vell.) Brenan var. cebil (Gris.) Alts.) como curtente vegetal para a produção de couros. A exploração florestal tem ocorrido sem atender a quaisquer dos preceitos para o regime de manejo sustentável, fazendo com que a preocupação com o uso indiscriminado das florestas aumente que, como consequência, resultará no surgimento de áreas degradadas. Apesar da importância da vegetação da Caatinga como fonte de energia e para a produção de taninos (cascas) é grande a carência de informações, principalmente, tecnológicas sobre os temas. Reconhecendo a importância do ecossistema Caatinga para a Região Nordeste do Brasil, a necessidade de maior conhecimento sobre a sua flora, bem como a escassez de pesquisas nesta área, o desenvolvimento desta tese teve como objetivos contribuir com a disponibilização de informações sobre o potencial para a produção de extratos tânicos (taninos vegetais) a partir de espécies florestais da Caatinga e avaliar a viabilidade técnica da utilização dos extratos obtidos para utilização no processo de curtimento de peles caprinas, para a produção de couros. Pretendeu-se assim, contribuir para redução da pressão antrópica sobre a espécie florestal angicovermelho (Anadenanthera colubrina var. cebil), que ocorre de forma mais acentuada na mesorregião do Cariri paraibano, por meio do desenvolvimento de pesquisas tecnológicas de utilização dos extratos tânicos (taninos vegetais) das espécies juremapreta (Mimosa tenuiflora) e jurema-vermelha (Mimosa arenosa) no processo de curtimento de peles caprinas. Pretendeu-se ainda, analisar a viabilidade técnica da utilização dos extratos tânicos das espécies, por meio das características físicomecânicas dos couros produzidos. Os extratos tânicos das espécies jurema-preta e jurema-vermelha produziram couros com bom aspecto e de coloração clara, com boa maciez e flexibilidade, e apresentaram características físico-mecânicas superiores as produzidas com o extrato de angico-vermelho. O extrato tânico da espécie jurema-preta foi superior aos extratos das demais espécies. O extrato de jurema-vermelha foi superior ao de angico-vermelho, tendo se igualado no quesito alongamento e apenas na direção paralela. Com relação às características relativas à flor, novamente o extrato tânico da espécie jurema-preta demonstrou-se superior aos demais, tanto na distensão como para a resistência à ruptura da flor. O extrato de jurema-vermelha foi superior ao de angicovermelho apenas para a distensão da flor, enquanto que para a resistência à ruptura da flor eles se equivalem, com pequena superioridade numérica para o de juremavermelha. Os resultados da pesquisa permitem concluir que é tecnicamente possível promover uma significativa redução da pressão antrópica sobre a espécie florestal angico-vermelho (Anadenanthera colubrina var. cebil), por meio da substituição do uso de cascas de angico-vermelho por extratos tânicos obtidos das espécies jurema-preta (Mimosa tenuiflora) e jurema-vermelha (Mimosa arenosa) no processo de curtimento de peles caprinas para a produção de couros. / In recent decades with population growth and technological advances that have occurred a significant increase pressure on the native flora in many regions in different parts of the world including semi-arid region of Brazil (Caatinga) in varied ways, there is the production of firewood and charcoal, and use the bark of angico-vermelho (Anadenanthera colubrina (Vell.) Brenan var. cebil (Gris.) Alts.) as vegetable tanning agent for leather production. The logging has occurred without regard to any of the provisions for the sustainable management regime causing concern about the indiscriminate use of forests that increase as a consequence result in the appearance of degraded areas. Despite the importance of the Caatinga vegetation as a source of energy and the production of tannins (bark) is a great lack of information mainly on technological issues. Recognizing the importance of the Caatinga ecosystem in the northeastern region of Brazil the need for more knowledge about its flora as well as the scarcity of research in this area developing this thesis aimed to contribute to the provision of information about the potential for production of tannin extracts (tannins) from the Caatinga forest species and evaluate the technical feasibility of the use of extracts for use in the process of tanning hides of goats for the production of leather. It was intended thus contribute to reducing human pressure on forest species angicovermelho (Anadenanthera colubrina var. cebil) which occurs more steeply in the Cariri region through the development of technological research for the use of tannin extracts (tannins) from the species jurema-preta (Mimosa tenuiflora) and jurema-vermelha (Mimosa arenosa) in the process of tanning goat production. The intention was also to examine the technical feasibility of the use of tannin extracts of species by means of physical and mechanical properties of leather produced. The tannin extracts of the jurema-preta and jurema-vermelha species produced leather look good and light coloring with good softness and flexibility and showed physical and mechanical properties superior to those produced with the extract of the angico-vermelho. The tannic extract of the Jurema’s species was superior to the extracts of other species. The tannic extract of the jurema-vermelha was superior to that of angico-vermelho and equaled only in the elongation in the parallel direction. With respect to characteristics related to flower again the tannic extract the jurema’s species shown to be superior to others much as in strain to the tensile strength of the flower. The extract the juremavermelha was superior to the angico-vermelho only to distend the flower while for the tensile strength of the flower they are equal with a slight numerical superiority for a jurema-vermelha. The survey results support the conclusion that it is technically possible to promote a significant reduction of anthropogenic pressure on forest species angico-vermelho (Anadenanthera colubrina var. cebil), by substituting the use of angico-vermelho bark for the tannin extracts obtained by species jurema-preta (Mimosa tenuiflora) and jurema-vermelha (Mimosa arenosa) in the process of tanning goat skins for leather production.
138

Otimiza??o do processo de recupera??o do cromo de efluentes de curtumes por microemuls?es no extrator Morris / Optimisation of chromium recovery process from tanning effluent through micro emulsions in a Morris extractor

Moura, Maria Carlenise Paiva de Alencar 19 May 2006 (has links)
Made available in DSpace on 2014-12-17T15:01:22Z (GMT). No. of bitstreams: 1 MariaCPAM.pdf: 984936 bytes, checksum: 2ad822e0048cda570ce57a014ed42a7c (MD5) Previous issue date: 2006-05-19 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The tanning industries are those which transform animal hide or skin into leather. Due to the complexity of the transformation process, greater quantities of chemicals are being used which results in the generation of effluents with residual solids. The chromium in the residual waters generated by tanning tend to be a serious problem to the environment, therefore the recovery of this metal could result in the reduction of manufacturing costs. This metal is usually found in a trivalent form which can be converted into a hexavalent compound under acidic conditions and in the presence of organic matter. The present study was carried out with the objective to recover chromium through an extraction/re-extraction process using micro emulsions. Micro emulsions are transparent and thermodynamically stable system composed of two immiscible liquids, one forming the continuous phase and the other dispersed into micro bubbles, established by an interfacial membrane formed by surface active and co-surface active molecules. The process of recovering the chromium was carried out in two stages. The first, an extraction process, where the chromium was extracted in the micro emulsion phase and the aqueous phase in excess was separated. In the second stage, a concentrated acid was added to the micro emulsion phase rich in chromium in order to obtain a Winsor II system, where the water that formed in the micro emulsion phase separates into a new micro emulsion phase with a higher concentration of chromium, due to the lowering of the hydrophiles as well as the ionisation of the system. During the experimental procedure, a study was initiated with a synthetic solution of chromium sulphate passing onto the effluent. A Morris extractor was used in the extraction process. Tests were carried out according to the plan and the results were analysed by statistical methods in order to optimise the main parameters that influence the process: the total rate of flow (Q), stirring speed (w) and solvent rate (r). The results, after optimization, demonstrated that the best percentuals in relation to the chromium extraction (99 %) were obtained in the following operational conditions: Q= 2,0 l/h, w= 425 rpm and r= 0,375. The re-extraction was carried out at room temperature (28 ?C), 40 ?C and 50?C using hydrochloric acid (8 and 10 M) and sulphuric acid (8 M) as re-extracting agents. The results obtained demonstrate that the process was efficient enough in relation to the chromium extraction, reaching to re-extraction percentage higher than 95 %. / Os Curtumes s?o ind?strias que transformam peles em couro. Devido a complexidade do processo de transforma??o s?o utilizadas grandes quantidades de agentes qu?micos e gerados grandes volumes de efluentes e res?duos s?lidos. O cromo presente nas ?guas residu?rias geradas pelos curtumes constitui um s?rio problema ambiental e sua recupera??o poder? representar uma redu??o nos custos do processo. Normalmente encontra-se na forma trivalente podendo ser convertido a cromo hexavalente sob condi??es ?cidas e na presen?a de mat?ria org?nica. Este estudo foi realizado com o objetivo de recuperar o cromo atrav?s de um processo de extra??o/reextra??o utilizando microemuls?es. As microemuls?es s?o sistemas transparentes, termodinamicamente est?veis, constitu?dos por dois l?quidos imisc?veis, um formando a fase cont?nua e o outro disperso na forma de microgot?culas, estabilizadas por uma membrana interfacial formada por mol?culas de tensoativo e cotensoativo. O processo de recupera??o do cromo ocorre em duas etapas. Na primeira, a extra??o, o cromo ? extra?do para a fase microemuls?o e a fase aquosa em excesso ? separada. A segunda etapa, ? realizada adicionando-se a fase microemuls?o, rica em cromo, um ?cido concentrado visando a obten??o de um sistema Winsor II, em que parte da ?gua que formava a fase microemuls?o, devido a diminui??o da hidrofilia e ioniza??o do sistema, se desloca formando uma nova fase aquosa, mais concentrada em cromo. Durante o procedimento experimental, iniciou-se o estudo com uma solu??o sint?tica de sulfato de cromo passando-se, em seguida, ao efluente. No processo de extra??o do cromo em escala semi-piloto utilizou-se o extrator Morris. Os ensaios foram efetuados seguindo um planejamento experimental e os resultados obtidos foram analisados, atrav?s de m?todos estat?sticos, visando a otimiza??o dos principais par?metros que influenciam no processo: vaz?o total (Q), velocidade de agita??o (w) e taxa de solvente (r). Os resultados obtidos, ap?s a otimiza??o, demonstraram que os maiores percentuais de extra??o (99 %) s?o obtidos nas seguintes condi??es operacionais: Q=2,0 l/h, w= 425 rpm e r= 0,375. A reextra??o foi realizada a temperatura ambiente (28 ?C) e a 40?C e 50?C utilizando-se como agente reextratante ?cido clor?drico (8 e 10 M) e ?cido sulf?rico (8 M). Os resultados obtidos demonstraram que o processo foi eficiente com rela??o ao cromo, obtendo-se percentuais de reextra??o acima de 95%
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Estudo de associação do polimorfismo de base única no códon 72 do gene humano p53 e as características de pigmentação / Association study of single-base polymorphism at codon 72 of human p53 gene and characteristics of pigmentation

COSTA, Kárita Antunes 30 March 2010 (has links)
Made available in DSpace on 2014-07-29T15:16:28Z (GMT). No. of bitstreams: 1 karita antunes costa.pdf: 2247292 bytes, checksum: e3c53812f8fcfba9aaaf69bdcbf978e3 (MD5) Previous issue date: 2010-03-30 / The p53 gene encodes a protein which has various functions such as monitoring of the cell cycle, role in repair mechanisms and apoptosis. New functions performed by this protein have been observed and studied as acting in the cascade of skin pigmentation by acting as transcription factor for genes important in this process as POMC (pro-opiomelanocortin) and MC1R (melanocortin receptor 1). Among the genetic polymorphisms, the codon 72 p53 gene is the most commonly studied and this variant has been associated with increased risk for various cancers, including skin. However, the association between this and other types of cancers has generated controversial results. The polymorphism occurs in a substitution G / C codon 72 p53 gene resulting in a change of amino acid sequence (CGC to CCC for arginine and proline). This polymorphism occurs in areas rich in proline generating morphophysiological changes as well as a difference in electrophoretic mobility of the protein. The aim of this study was to establish a possible association between the codon 72 polymorphism of p53 gene with the characteristics of pigmentation such as skin color, hair, eye and skin response after exposure to sunlight (reddening or bronze). The 96 healthy volunteers were recruited randomly and information on skin color, ability to tan and other characteristics of pigmentation were collected through a standardized questionnaire. Genomic DNA was extracted from venous blood and genotyping was performed by polymerase chain reaction (PCR). The polymorphism was investigated by photo documentation after agarose gel electrophoresis. Samples that generated doubts were confirmed by digestion with sitespecific action of the restriction enzyme BstUI. Allele frequencies of 96 volunteers to p53Arg/72 and p53Pro/72 were 67.70% and 32.30% respectively. Genotype frequencies for Arg / Arg, Arg / Pro and Pro / Pro were 50.00% 35.40% 14.60% respectively. We did not detect a significant association between reddening or tanning after sun exposure with the polymorphism (p = 0.678), on the other hand we observed an association between the genotype Pro / Pro and blue eyes / green (p = 0.01) among showing redness of the skin, demonstrating a disadvantage in relation to the sun when there is occurrence of this specific phenotype (eye color) combined with the genotype Pro / Pro. / O gene p53 codifica uma proteína à qual exerce várias funções como monitoramento do ciclo celular, atuação em mecanismos de reparo e apoptose. Novas funções exercidas por essa proteína vêm sendo observadas e estudadas como a atuação na cascata de pigmentação da pele agindo como fator de transcrição para genes importantes nesse processo como POMC (Pro-opiomelanocortina) e MC1R (receptor melanocortina 1). Dentre os polimorfismos genéticos, o do códon 72 do gene p53 é o mais comumente estudado e esta variante tem sido associada ao risco elevado para vários tipos de cânceres, incluindo os de pele. No entanto, a associação entre este e outros tipos de cânceres tem gerado resultados controversos. O polimorfismo ocorre por uma substituição G/C no códon 72 do gene p53 resultando em uma mudança da sequência de aminoácidos (CGC para arginina e CCC para prolina). Esse polimorfismo ocorre em domínios ricos em prolina gerando alterações morfofisiológicas assim como, uma diferença na mobilidade eletroforética da proteína. O objetivo do presente estudo foi estabelecer uma possível associação entre o polimorfismo do códon 72 do gene p53 com as características de pigmentação como cor de pele, cabelo, olho e resposta da pele após exposição solar (apresentar vermelhidão ou se bronzear). Os 96 voluntários saudáveis foram recrutados randomicamente e as informações sobre cor de pele, capacidade de se bronzear e outras características de pigmentação foram coletadas mediante um questionário padronizado. O DNA genômico foi extraído a partir do sangue venoso e a genotipagem foi feita por Reações em Cadeia da Polimerase (PCR). O polimorfismo foi investigado por fotodocumentação após eletroforese em gel de agarose. As amostras que geraram dúvidas foram confirmadas por digestão sítio específica através da atuação da enzima de restrição BstUI. As frequências alélicas dos 96 voluntários para p53Arg/72 e p53Pro/72, foram 67,70% e 32,30% respectivamente. As freqüências genotípicas para Arg/Arg, Arg/Pro e Pro/Pro foram 50,00%, 35,40% 14,60% respectivamente. Não foi detectada associação significante entre apresentar vermelhidão ou se bronzear após a exposição solar com o polimorfismo (p = 0,678), por outro lado observamos uma associação entre o genótipo Pro/Pro e olhos azuis/verdes (p = 0,01) entre os que apresentam vermelhidão da pele, demonstrando uma desvantagem em relação a exposição solar quando há ocorrência deste fenótipo específico (cor de olho) aliado ao genótipo Pro/Pro.
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2. Freiberger Ledertage - Abstractband: 25. und 26. April 2013, Sinsheim: Leder up to date

Schubert, Eva 15 January 2019 (has links)
Der Verein für Gerberei-Chemie und -Technik (VGCT) wurde 1949 zur Förderung wissenschaftlicher und technischer Forschung, zum Zwecke des fachlichen Erfahrungsaustausches sowie zur Förderung des beruflichen Nachwuchses gegründet. Gegenwärtig hat er ca. 300 Mitglieder, welche sowohl einzelne Personen als auch Firmen sind. Im VGCT treffen sich Ledertechniker, Maschinenbauer, Chemiker und andere am „Ledermachen“ interessierte Menschen zum Austausch und zu gemeinsamer Arbeit. Der Verein bietet eine Plattform für den fachlichen Austausch indem er jährliche Fachtagungen und fachliche Kooperationen in firmenübergreifenden Arbeitsgruppen (Kommissionen) organisiert, technische Veröffentlichungen in der Fachpresse mit eigenen Seiten fördert und sich aktiv an Umweltschutz, Arbeitssicherheit sowie Gesundheitsschutz beteiligt. / The Association for Chemistry and Technology in Tanning (VGCT) was founded in 1949 in order to facilitate scientifi c and technical research and exchange of professional experience as well as to promote young talents. Currently it has some 300 members – single persons as well as enterprises. In the VGCT, leather technologists, mechanical engineers, chemists and other people interested in “making leather” meet in order to exchange ideas and work together. The association offers a platform for sharing professional experience by organizing annual meetings and professional co-operations in groups from across various companies (commissions), by facilitating technical publications in specialist press with own pages and actively participating in environmental protection, occupational safety and health protection.

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