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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.
61

Uso de um lodo de cromo proveniente da indústria de curtume na fabricação de vidros sodo-cálcicos. / Use of tannery sludge containing chromium compounds in soda-lime glass fabrication.

Peralta, Marvin Marco Chambi 12 August 2014 (has links)
A indústria de produção de couro gera uma grande quantidade de resíduos com características poluentes e de elevada periculosidade, entre os quais se destacam os resíduos curtidos (aparas, serragem e pó de couro curtido) e os lodos provenientes das estações de tratamento de efluentes (lodos de cromo, lodos primários e lodos secundários). Estes resíduos possuem uma considerável quantidade de compostos de Cr(III) na sua composição, os quais, sob condições oxidantes, podem transformar-se em Cr(VI), que é altamente tóxico para animais, plantas e seres humanos. No entanto, estes resíduos constituem uma potencial fonte alternativa de cromo (tradicional pigmento industrial) que poderia ser aproveitada pela indústria de vidros e de esmaltes. No presente trabalho foi realizado o estudo das propriedades físicas e químicas de um lodo de cromo proveniente do distrito industrial do município de Franca/SP, com o intuito de avaliar a viabilidade da utilização das cinzas da incineração deste resíduo como uma potencial fonte alternativa de cromo na fabricação de vidros sodo-cálcicos coloridos para embalagens. Fluorescência de Raios X (FRX), Difração de Raios X (DRX), análises termodiferencial (DTA) e termogravimétrica (TG/DTG), análise elementar, análise granulométrica, determinação de poder calorífico pelo método da bomba calorimétrica e Microscopia Eletrônica de Varredura (MEV) foram usados para determinar as características físicas e químicas do lodo de cromo. A incineração do resíduo foi realizada numa mufla elétrica a 800 C, utilizando um cadinho de alumina. A determinação da concentração de íons Cr(VI) presentes no lodo e nas cinzas foi realizada através do método colorimétrico utilizando difenilcarbazida. Vidros sodo-cálcicos contendo as cinzas da incineração do lodo de cromo foram preparados por meio da fusão das matérias-primas industriais (areia, barrilha e calcário) em cadinhos de alumina a 1500 C por 1h, sob condições similares às utilizadas no processo industrial de produção de vidros comerciais de coloração verde (composição, adição de ferro e condições redutoras). Para fins de comparação, foram preparadas também amostras de vidros contendo cromita (tradicional fonte industrial de cromo utilizada pela indústria de vidros) sob condições semelhantes. As amostras de vidros foram caracterizadas em termos de composição química por FRX, MEV, DRX, coordenadas colorimétricas (sistema CIEL*a*b*) e absorção óptica. Os resultados de FRX mostraram que as cinzas apresentam um teor de cromo de aproximadamente 47% em massa de Cr2O3, valor não muito distante do teor de cromo observado na composição da cromita (cerca de 43% em massa de Cr2O3). Os vidros preparados utilizando cromita e as cinzas da incineração de lodo de cromo apresentaram bandas de absorção óptica semelhantes no intervalo analisado (200-3300 nm), sem a presença aparente da banda de absorção óptica entorno de 370 nm, característica do íon Cr6+. Estes resultados sugerem que sob condições adequadas de incineração do lodo, bem como formulação e fusão do vidro, é possível utilizar-se as cinzas obtidas como fonte alternativa de cromo para a fabricação de vidros coloridos do sistema soda-cal-sílica. / Leather production industry generates large quantities of solid wastes with pollutant characteristics and hazardous conditions, such as tanned wastes (Chrome shaving, chrome splits and buffing dust) and sludges from wastewater treatment process (Tannery sludge, primary and secondary sludge). These wastes containing Cr(III), which, under oxidizing conditions, can turn into Cr(VI), an extremely toxic and cancerigenous form of the element. However, these wastes are a potential source of chromium (traditional industrial pigment) which could be used by the glass and ceramic enamels industries. In the present work was studied the physical and chemical properties of a tannery sludge from the industrial district of the city of Franca, São Paulo State, Brazil, in order to evaluate the feasibility of using the ashes from incineration of this waste as a potential alternative source of chromium for the manufacturing of soda-lime glasses. X-Ray Fluorescence (XRF), Xray Diffraction (XRD), Differential Thermal Analysis (DTA), Thermogravimetric Analysis (TG/DTG), elemental analysis, granulometric analysis, determination of calorific value by the bomb calorimeter method and Scanning Electron Microscopy (SEM) were used to determine the physical and chemical characteristics of tannery sludge. The tannery sludge incineration was performed using an alumina crucible in a electric oven at 800 C. Colorimetric method using diphenylcarbazide were conducted to determinate the Cr(VI) concentration in the waste and the ashes from incineration. Soda-lime glass containing the ashes from incineration of tannery sludge was prepared by melting of industrial raw materials (sand, soda ash and limestone), in alumina crucibles at 1500 C for 1 hour, under similar conditions to those used in the industrial production process of commercial green container glasses (composition, addition of iron and reducing conditions). For comparison purposes, glasses containing chromite (traditional industrial source of chromium used by the glass industry) were also prepared under similar conditions. The glass samples were characterized in terms of chemical composition by XRF, MEV, DRX, color (CIEL*a*b* system) and optical absorption. The FRX results revealed that the ashes are composed by about 47 wt% Cr2O3. This amount is not so far from the chromium content observed in the composition of chromite (about 43 wt% Cr2O3). The glasses containing chromite and the ashes from the incineration of the tannery sludge exhibited approximately similar optical absorption bands in the analyzed range (200-3300 nm), without the presence of optical absorption band around 370 nm, characteristic of Cr 6+. These results suggests that under appropriate incineration conditions of the sludge, as well as formulation and melting of glass, is possible use the chromium-rich ashes from incineration of tannery sludge as an alternative source of chromium for the manufacturing of colored glasses of the soda-lime-silica system.
62

Death in the City: The St. Lawrence Funeral Centre

Brown, Liam David Renshaw January 2012 (has links)
In contemporary North America, death is contained within a network of cemeteries, crematoria and funeral homes. Death-space and its associative funeral rituals are both sacred and abject resulting in marginalization that adversely affects how the living understand their mortality. Our perception of death influences our place in the world and funeral ritual facilitates our departure from it. In most cities, the funeral home houses this liminal ritual, while also providing the clinical handling and processing of the deceased body. Investigation of the funeral home and its role within the city addresses how architecture can influence cultural views on death. Through the funeral home there is an opportunity to balance the seemingly opposing narratives of the living and the deceased by bringing them together for the funeral. In the City of Toronto, the density of its diverse neighbourhoods is not reflected by a proportionate number of local funeral homes. This thesis proposes a non-denominational space for funeral ritual and cremation within the dense St. Lawrence Neighbourhood. The placement of the Funeral Centre satisfies the practical requirements of this growing community, while the adjacency to the St. Lawrence Market juxtaposes the vibrancy of the ordinary and the solemnity of the sacred. This proposal extends into a network for the scattering of ashes throughout the city aiming to reconnect people to the realities of their existence.
63

Death in the City: The St. Lawrence Funeral Centre

Brown, Liam David Renshaw January 2012 (has links)
In contemporary North America, death is contained within a network of cemeteries, crematoria and funeral homes. Death-space and its associative funeral rituals are both sacred and abject resulting in marginalization that adversely affects how the living understand their mortality. Our perception of death influences our place in the world and funeral ritual facilitates our departure from it. In most cities, the funeral home houses this liminal ritual, while also providing the clinical handling and processing of the deceased body. Investigation of the funeral home and its role within the city addresses how architecture can influence cultural views on death. Through the funeral home there is an opportunity to balance the seemingly opposing narratives of the living and the deceased by bringing them together for the funeral. In the City of Toronto, the density of its diverse neighbourhoods is not reflected by a proportionate number of local funeral homes. This thesis proposes a non-denominational space for funeral ritual and cremation within the dense St. Lawrence Neighbourhood. The placement of the Funeral Centre satisfies the practical requirements of this growing community, while the adjacency to the St. Lawrence Market juxtaposes the vibrancy of the ordinary and the solemnity of the sacred. This proposal extends into a network for the scattering of ashes throughout the city aiming to reconnect people to the realities of their existence.
64

An evaluation of chicken litter ash, wood ash and slag for use as lime and phosphate soil amendments

Yusiharni, Baiq Emielda January 2007 (has links)
[Truncated abstract] Standard AOAC methods of chemical analysis have been used to characterize and evaluate the industrial byproducts; partly burnt chicken litter ash (CLA), totally burnt chicken litter ash (CLAT), wood ash (WA) and iron smelting slag for use as a combined liming agent and phosphate fertilizer. Rock phosphate has this function and was included for comparison purposes. All the byproducts had pH values above 9 and a liming capacity above 90% of pure lime, as a result, these materials will be effective as liming agents. Total P concentrations for CLA, CLAT, slag, and WA were 3.6%, 4.75%, 0.26%, and 0.44% respectively indicating that they could be used as P fertilizers when applied at the high rates required for liming soils. ... The RE values for all the materials relative to monocalcium phosphate (100%) for the first harvest are as follows, 50% for dicalcium phosphate, 31% for rock phosphate, 7% for partly burnt chicken litter ash, 7% for totally burnt chicken litter ash and 1% for wood ash and slag. The RE values for the second harvest were 100% for monocalcium phosphate, 80% for dicalcium phosphate, 40% for rock phosphate, 10% for partly burnt chicken litter ash, 8% for totally burnt chicken litter ash and 2% for wood ash and slag. Data for subsequent harvests are not reported due to the death of many plants. Clearly chicken litter ash has appreciable value as a phosphate fertilizer whereas wood ash and slag are ineffective. Explanations for these differences in effectiveness are discussed in the text. An evaluation of the liming effect of the byproducts indicates that they may be used as a soil amendment on acid soils and are nearly as effective as standard lime (CaCO3). Byproducts are also sources of other plant nutrients so they may be regarded as a form of compound fertilizer and liming agent.
65

From wood to waste and waste to wood : aspects on recycling waste products from the pulp mill to the forest soil /

Rothpfeffer, Caroline, January 2007 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.
66

Accumulation of elements in Salix and other species used in vegetation filters with focus on wood fuel quality /

Adler, Anneli, January 2007 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.
67

Estudo da potencialidade da incorpora??o de res?duo de granito e da queima da casca do caf? em cer?mica vermelha

Avelino, Keite Anny Rocha 29 November 2013 (has links)
Made available in DSpace on 2014-12-17T14:07:15Z (GMT). No. of bitstreams: 1 KeiteARA_DISSERT.pdf: 2612937 bytes, checksum: ec59db9fd6d1145d803c85bac8a8f46c (MD5) Previous issue date: 2013-11-29 / The industrial production of ornamental rocks and the burning of coffee husk generate waste that is discarded into the environment. However, with the study of the incorporation of these residues in ceramic products, may be found an alternative to reducing environmental impacts and detrimental effects on human health caused by its indiscriminate disposal of waste in nature. Thus, this work aimed to study the addition of ashes of the coffee husk and granite residue in matrix of red ceramic. The raw materials were dry milled and sieved to mesh 100. To characterize the raw materials were carried out analyzes of X-ray diffraction (XRD), X-ray fluorescence (XRF), particle size analysis (PSA), differential thermal analysis (DTA) and thermogravimetric analysis (TG). Six formulations were prepared where the clay content was kept constant (70%wt) and ashes contents and granite residue varied from 10, 15, 20 and 30%. Dilatometrics analyzes were performed at four selected formulations, containing them: 100% clay (A100); 70% clay and 30% ashes (A70C30); 70% clay and 30% granite residue (A70G30); and 70% clay, 15% granite residue and 15% ashes (A70G15C15). The samples were prepared by uniaxial compaction with pressure of 25 MPa, and fired at temperatures of 800?C, 850?C, 900?C, 950?C, 1000?C and 1100?C. Assays were performed to determine the linear shrinkage of burning (LSB), water absorption (WA), apparent porosity (AP), density (D) and tensile bending. Also were performed analyzes of X-ray diffraction (XRD) and scanning electron microscopy (SEM) of the samples fired. The formulations incorporating granite residue and/or ashes reached the required limits of water absorption according to NBR 15270-1 and NBR 15310 and tensile bending according to classical literature (SANTOS, 1989) necessary for the production of tiles and ceramic block for masonry sealing / A produ??o industrial de rochas ornamentais e a queima da casca do caf? geram res?duos que s?o descartados no meio ambiente. Por?m, com o estudo da incorpora??o destes res?duos em produtos cer?micos, poder? ser encontrada uma alternativa para a redu??o dos impactos ambientais e efeitos danosos ? sa?de humana causados pelo seu descarte indiscriminado na natureza. Nesse sentido, este trabalho teve como objetivo estudar a adi??o de cinzas da casca do caf? e res?duo de granito na argila usada para a produ??o de cer?mica vermelha. As mat?rias-primas foram mo?das a seco e peneiradas na malha 100 mesh. Para caracterizar as mat?rias-primas foram realizadas as an?lises de difra??o de raios X (DRX), fluoresc?ncia de raios X (FRX), an?lise granulom?trica (AG), an?lise t?rmica diferencial (DTA) e an?lise termogravim?trica (TG). Foram preparadas seis formula??es onde o teor de argila foi mantido constante (70% em peso) e os teores de cinzas e de res?duo de granito variaram de 10, 15, 20 e 30%. Foram realizadas an?lises dilatom?tricas em quatro formula??es selecionadas, contendo elas: 100% argila (A100); 70% argila e 30% cinza (A70C30); 70% argila e 30% res?duo de granito (A70G30); e 70% argila, 15% res?duo de granito e 15% cinza (A70G15C15). As amostras foram confeccionadas por compacta??o uniaxial com press?o de 25 MPa, e queimadas ?s temperaturas de 800?C, 850?C, 900?C, 950?C, 1000?C e 1100?C. Foram realizados ensaios para determinar a retra??o linear de queima (RLq), absor??o de ?gua (AA), porosidade aparente (PA), massa espec?fica aparente (MEA) e tens?o de ruptura ? flex?o (TRF). Foram realizadas tamb?m an?lises de difra??o de raios X (DRX) e microscopia eletr?nica de varredura (MEV) das amostras queimadas. As formula??es com incorpora??o de res?duo de granito e/ou cinza alcan?aram os limites exigidos de absor??o de ?gua segundo as normas NBR 15270-1 e 15310 e de tens?o de ruptura ? flex?o segundo a literatura cl?ssica (SANTOS, 1989), necess?rios para a produ??o de telhas e blocos cer?micos para alvenaria de veda??o
68

Utilizacao da cinza da casca de arroz como carga em matriz de poliamida 6 submetida a radiacao ionizante / Utilization of rice husk ash as filler for polyamide 6 and ionizing radiation effect studies on this composite

FERRO, WALDIR P. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:26:24Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:09:59Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
69

Potencial da cinza do bagaço da cana-de-açúcar como material de substituição parcial de cimento Portland / Potential of the sugarcane bagasse ash as a partial replacement material for cement Portland

Paula, Marcos Oliveira de 22 August 2006 (has links)
Made available in DSpace on 2015-03-26T13:23:21Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1441039 bytes, checksum: 1a4c158d5650dd52d4cba8016e068631 (MD5) Previous issue date: 2006-08-22 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / This study was carried out to evaluate the potential of the sugarcane bagasse ash (CBC) as partial replacement material for the Portland cement in mortar. A residue generated at the Jatiboca sugar mill located in Urucânia county-MG was used as CBC. The use of the sugarcane bagasse as an ash source for mineral addition into cement-based materials is subjected to two factors: the production and chemical constitution of the ash. The sugarcane bagasse ash (CBC) is predominantly composed by silicon dioxide, that can develop pozollan activity depending on the characteristics of both burning and grain size. In this case, the reactivity between silica and the hydration products may improve the physical and mechanical properties of the cement-based materials with incorporated residues. The work was divided into two phases: CBC characterization and the evaluation of its addition to mortar, by using mechanical and physical assays. According to the results, the sugarcane bagasse showed 10% CBC production. CBC presents 84% SiO2 and 5% carbon. The CBC silica is shown either in amorphous phase and crystalline phase of Crystobalite and Quartz. Concerning to grain size and surface area, the ash under study is composed by either particles at the size range from 1 to 14 μm and specific surface area of 24 m2/g. When considering the initial and final time of the mortar hardening, it was observed that the additions of 10%, 20% and 30% CBC caused a 10min delay in the interval between the times of mortar hardening. Relative to pozzolan activity indexes, the results corroborate the reactivity by CBC. It was also observed that the mortars with higher ash contents tend to be more porous, which justifies the highest values found for absorption. Regarding the specific mass, the partial substitution of the Portland cement up to 30% ashes in the mixture provoked no significant modification. The mortar compression assays with CBC contents between zero and 30%, that were accomplished at 7th and 28th days pointed out the possibility for replacement up to 20% cement by CBC with no damaged resistance. / Este trabalho teve como objetivo avaliar o potencial da CBC como material de substituição parcial do cimento Portland em argamassa. A CBC empregada é um resíduo gerado na usina de açúcar Jatiboca, localizada no município de Urucânia-MG. A utilização do bagaço da cana de açúcar como fonte de cinza como adição mineral em materiais à base de cimento obedece a dois fatores: o rendimento de cinza e a sua constituição química. A cinza do bagaço da cana-de-açúcar (CBC) é composta predominantemente por dióxido de silício, o qual, dependendo das características de queima e da granulometria, pode desenvolver atividade pozolânica. Neste caso, a reatividade entre sílica e os produtos de hidratação podem acarretar em melhoria nas propriedades físicas e mecânicas doas materiais à base de cimento com incorporação de resíduos. O trabalho foi dividido em duas fases: caracterização da CBC e avaliação do seu emprego como adição em argamassa através de ensaios mecânicos e físicos. Os resultados mostraram que o bagaço apresenta um rendimento de CBC de 10%. A cinza de CBC apresenta 84% de SiO2 e 5% de carbono. A sílica na CBC apresenta-se tanto na fase amorfa quanto nas fases cristalinas de Cristobalita e Quartzo. Os resultados encontrados para a composição granulométrica e área de superfície demonstraram que a cinza em estudo é composta por partículas com tamanhos entre 1 e 14 μm e com uma área de superfície específica da ordem de 24 m2/g. Com relação ao estudo do tempo de pega inicial e final, foi observado que as adições de 10%, 20% e 30% de CBC acarretaram um retardo de 10 min no intervalo entre os tempos de pega. Os resultados encontrados para os índices de atividade pozolânica comprovam a reatividade da CBC. Observou-se que as argamassas com maiores teores de cinza tendem a ser mais porosas, o que justifica os maiores valores de absorção encontrados. Com relação à massa específica, a substituição parcial do cimento Portland por até 30% de cinzas na mistura não provocou qualquer modificação significativa. Os ensaios de compressão das argamassas com teores de CBC entre 0 e 30%, aos 7 e 28 dias, indicaram a possibilidade de substituição de até 20% do cimento pela CBC, sem prejuízo da resistência.
70

Utilizacao da cinza da casca de arroz como carga em matriz de poliamida 6 submetida a radiacao ionizante / Utilization of rice husk ash as filler for polyamide 6 and ionizing radiation effect studies on this composite

FERRO, WALDIR P. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:26:24Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:09:59Z (GMT). No. of bitstreams: 0 / Com o propósito de melhorar a estabilidade dimensional, melhorar propriedades de resistência elétrica, mecânica, ao calor entre outras dos polímeros, novas cargas e reforços são testados com esse propósito. As cargas mais utilizadas, para propiciar as características mencionadas anteriormente, são as fibras de vidro e de carbono, as cargas minerais como o carbonato de cálcio precipitado, o talco e a micro esfera de vidro. O objetivo principal deste trabalho foi estudar as potencialidades da cinza da casca de arroz (CCA) como uma carga, já que ela é constituída em 96% de dióxido de silício e compará-la com o talco que é a carga mineral mais utilizada. Estes estudos foram realizados a partir da elaboração de um composto formado pela cinza da casca de arroz refinada e a poliamida 6 (PA 6) que é um dos principais plásticos de engenharia com aplicações em todas as áreas produtivas. As amostras foram injetadas e irradiadas em um acelerador de elétrons. Posteriormente suas propriedades mecânicas e térmicas foram medidas. Também foram injetadas peças automotivas para verificar a processabilidade da PA 6 com CCA. Os resultados mostraram que a utilização da cinza da casca de arroz como carga para compostos de poliamida 6 é tecnicamente e economicamente viável. A irradiação do composto estudado (PA 6 com 30% de cinza da casca de arroz) não trouxe melhorias significativas nas propriedades mecânicas e térmicas avaliadas. / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

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