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1
Lammers, Kristin D. "Carbon dioxide sequestration by mineral carbonation of iron-bearing minerals". Diss., Temple University Libraries, 2015. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/339925.
Testo completoAbstract (sommario):
ChemistryPh.D.
Carbon dioxide (CO2) is formed when fossil fuels such as oil, gas and coal are burned in power producing plants. CO2 is naturally found in the atmosphere as part of the carbon cycle, however it becomes a primary greenhouse gas when human activities disturb this natural balanced cycle by increasing levels in the atmosphere. In light of this fact, greenhouse gas mitigation strategies have garnered a lot of attention. Carbon capture, utilization and sequestration (CCUS) has emerged as a possible strategy to limit CO2 emissions into the atmosphere. The technology involves capturing CO2 at the point sources, using it for other markets or transporting to geological formations for safe storage. This thesis aims to understand and probe the chemistry of the reactions between CO2 and iron-bearing sediments to ensure secure storage for millennia. The dissertation work presented here focused on trapping CO2 as a carbonate mineral as a permanent and secure method of CO2 storage. The research also explored the use of iron-bearing minerals found in the geological subsurface as candidates for trapping CO2 and sulfide gas mixtures as siderite (FeCO3) and iron sulfides. Carbon dioxide sequestration via the use of sulfide reductants of the iron oxyhydroxide polymorphs lepidocrocite, goethite and akaganeite with supercritical CO2 (scCO2) was investigated using in situ attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The exposure of the different iron oxyhydroxides to aqueous sulfide in contact with scCO2 at ~70-100 ˚C resulted in the partial transformation of the minerals to siderite (FeCO3). The order of mineral reactivity with regard to siderite formation in the scCO2/sulfide environment was goethite < lepidocrocite ≤ akaganéite. Overall, the results suggested that the carbonation of lepidocrocite and akaganéite with a CO2 waste stream containing ~1-5% H2S would sequester both the carbon and sulfide efficiently. Hence, it might be possible to develop a process that could be associated with large CO2 point sources in locations without suitable sedimentary strata for subsurface sequestration. This thesis also investigates the effect of salinity on the reactions between a ferric-bearing oxide phase, aqueous sulfide, and scCO2. ATR-FTIR was again used as an in situ probe to follow product formation in the reaction environment. X-ray diffraction along with Rietveld refinement was used to determine the relative proportion of solid product phases. ATR-FTIR results showed the evolution of siderite (FeCO3) in solutions containing NaCl(aq) concentrations that varied from 0.10 to 4.0 M. The yield of siderite was greatest under solution ionic strength conditions associated with NaCl(aq) concentrations of 0.1-1 M (siderite yield 40% of solid product) and lowest at the highest ionic strength achieved with 4 M NaCl(aq) (20% of solid product). Based partly on thermochemical calculations, it is suggested that a decrease in the concentration of aqueous HCO3- and a corresponding increase in co-ion formation, (i.e., NaHCO3) with increasing NaCl(aq) concentration resulted in the decreasing yield of siderite product. At all the ionic strength conditions used in this study, the most abundant solid phase product present after reaction was hematite (Fe2O3) and pyrite (FeS2). The former product likely formed via dissolution/reprecipitation reactions, whereas the reductive dissolution of ferric iron by the aqueous sulfide likely preceded the formation of pyrite. These in situ experiments allowed the ability to follow the reaction chemistry between the iron oxyhr(oxide), aqueous sulfide and CO2 under conditions relevant to subsurface conditions. Furthermore, very important results from these small-scale experiments show this process can be a potentially superior and operable method for mitigating CO2 emissions.
Temple University--Theses
2
Frost, Ray. "Studies of selected minerals, mineral surfaces and their colloidal dispersions". Thesis, Queensland University of Technology, 2001.
Cerca il testo completoAbstract (sommario):
This thesis is about the molecular structure of minerals, their surface modification and the dispersion of selected minerals of a ceramic nature as sols and gels. The
theme that permeates through this work and connects the different elements of the work is the search for fundamental knowledge and understanding of mineral structure
and mineral surface structure. The underlying principal is that of molecular structure of surfaces and the changes in that molecular structure through modification of the
surfaces.
There are seven research divisions of study reported in this thesis:
(A) Molecular structure and spectroscopy ofkaolinite
(B) Molecular surface structure modified through intercalation with polar
molecules
(C) Molecular surface structure modified through intercalation with potassium and
cesium acetates
(D) Structure and spectroscopy of alumina phases and colloids
(E) Structure and spectroscopy of titania and zirconia colloids
(F) Synthesis, characterisation and spectroscopy of double layered hydroxides
(hydrotalcites)
(G) Spectroscopic and molecular structural studies of selected minerals of interest
3
Adams, Adrian Richard. "The degradation of atrazine by soil minerals : effects of drying mineral surfaces". Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86515.
Testo completoAbstract (sommario):
Thesis (MScAgric)--Stellenbosch University, 2014.ENGLISH ABSTRACT: The herbicide atrazine (ATZ, 2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) has been identified as an environmental endocrine disruptor and possible human carcinogen. The presence of atrazine, along with its degradation products, in soils and water supplies therefore raises concern. Atrazine biodegradation in soils is well-covered to date, however, atrazine degradation by abiotic mineral surfaces, and the chemical mechanism by which it occurs, is not fully understood. Furthermore, with a changing global climate, the effects of wetting and drying cycles on soil processes (e.g. atrazine degradation) is largely unknown, but increasing in importance. This study therefore investigated atrazine degradation on six common soil mineral surfaces, namely birnessite, goethite, ferrihydrite, gibbsite, Al3+-saturated smectite and quartz, as well as the effects that drying these surfaces has on atrazine degradation. In the first part, a comparison was conducted between the reactivity of fully hydrated and drying mineral surfaces toward atrazine, by reacting atrazine-mineral mixtures under both moist and ambient drying conditions, in parallel, for 14 days. Under moist conditions, none of the mineral surfaces degraded atrazine, but under drying, birnessite and goethite degraded atrazine to non-phytotoxic hydroxyatrazine (ATZ-OH, 2-hydroxy-4-ethylamino-6-isopropylamino-1,3,5-triazine) as major product and phytotoxic deethylatrazine (DEA, 2-chloro-4-amino-6-isopropylamino-1,3,5-triazine) as minor product. The mineral surface reactivity was birnessite (66% degradation) > goethite (18% degradation) >> other mineral surfaces (negligible degradation), indicating possible atrazine oxidation. In the second part, the effects of drying rate were investigated on birnessite only (the most reactive surface), by conducting the drying (1) gradually at ambient rates, (2) rapidly under an air stream, and (3) gradually in the absence of water using only organic solvent. After 30 days of ambient drying, 90% of the atrazine was degraded to ATZ-OH and DEA, but the same extent of degradation was achieved after only 4 days of rapid drying with an air stream. Thirty days of gradual drying using only organic solvent did not increase atrazine degradation compared to the water-moist drying surface. In each case, degradation initiated at a critical moisture content of 10% of the original moisture content. In the third part, the degradation mechanism was further investigated. To test for the possible oxidation of atrazine by the birnessite surface, moist atrazine-birnessite mixtures were dried under a nitrogen (N2) stream to eliminate possible oxidation by atmospheric oxygen (O2). Dissolved Mn2+ was extracted at the end of the experiment to observe any reduction of birnessite. Under N2, the same products were formed as before, with no appreciable Mn2+ production, indicating non-oxidative atrazine degradation by birnessite. The final part investigated the effects ultraviolet (UV) radiation has on the degradation of atrazine by drying mineral surfaces. The UV-radiation enhanced the degradation of atrazine, but no other degradation products were formed. It was therefore concluded that atrazine degradation on redox-active soil mineral surfaces is enhanced by drying, via a net non-oxidative mechanism. Furthermore, this drying-induced degradation is an atrazine detoxification mechanism which could be easily applied through agricultural practices such as windrowing, ploughing and any other practice that (rapidly) dries a Mn- or Fe-oxide rich agricultural soil.
AFRIKAANSE OPSOMMING: Die onkruiddoder atrasien (ATS, 2-chloro-4-etielamino-6-isopropielamino-1,3,5-triasien) is as 'n omgewings endokriene versteurder en moontlike menslike karsinogeen geidentifiseer. Die teenwoordigheid van atrasien, tesame met sy afbreekprodukte, in grond en water toevoere wek dus kommer. Die bio-afbreking van atrasien in gronde is tot dusver goed gedek, maar die afbreking van atrasien deur abiotiese mineraaloppervlaktes, en die chemiese meganisme waarmee dit plaasvind, word nie heeltemal verstaan nie. Verder, met 'n veranderende globale klimaat, is die effekte van benatting- en drooging-siklusse op grondprosesse (bv. atrasien afbreking) grootliks onbekend, maar toenemend belangrik. Daarom het hierdie studie atrasien afbreek op ses algemene mineraaloppervlaktes, naamlik birnessiet, goethiet, ferrihidriet, gibbsiet, Al3+-versadigde smektiet en kwarts, ondersoek, asook die effekte wat drooging van hierdie oppervlaktes op atrasien afbreking het. In die eerste deel, was 'n vergelyking gedoen tussen die reaktiwiteit van volgehidreerde en droëende mineraaloppervlaktes teenoor atrasien, deur atrasien-mineraal mengsels, in parallel, onder albei nat en omliggende droogings toestande te reageer vir 14 dae. Onder nat toestande, het geeneen van die mineraaloppervlaktes atrasien afgebreek nie, maar onder drooging het birnessiet en goethiet atrasien afgebreek na nie-fitotoksiese hidroksieatrasien (ATS-OH, 2-hidroksie-4-etielamino-6-isopropielamino-1,3,5-triasien) as hoofproduk en fitotoksiese deetielatrasien (DEA, 2-chloro-4-amino-6-isopropielamino-1,3,5-triasien) as minder-produk. Die mineraaloppervlakte-reaktiwiteit was birnessiet (66% afbreking) > goethiet (18% afbreking) >> ander mineraaloppervlaktes (geringe afbreking), wat moontlike atrasien oksidasie aandui. In die tweede deel, is die effekte van droogingstempo ondersoek, op birnessiet alleenlik (die mees reaktiewe oppervlak) deur drooging by (1) 'n omliggende geleidelike tempo, (2) 'n versnelde tempo onder 'n lugstroom, en (3) 'n geleidelike tempo in die afwesigheid van water, deur slegs gebruik te maak van 'n organiese oplosmiddel. Na 30 dae se geleidelike drooging, is 90% van die atrasien afgebreek na ATS-OH en DEA, maar dieselfe hoeveelheid afbreking is bereik na slegs 4 dae onder versnelde drooging met die lugstroom. Dertig dae van geleidelike drooging met slegs organiese oplosmiddel het nie atrasien afbreking vermeerder in vergelyking met die water-nat droëende oppervlak nie. In elke geval, is afbreking geïnisieer by 'n kritiese water inhoud van 10% van die oorspronklike water inhoud. In die derde deel is die afbrekingsmeganisme verder ondersoek. Om te toets vir die moontlike oksidasie van atrasien deur die birnessiet oppervlak, is nat atrasien-birnessiet mengsels onder stikstof (N2) gedroog, om die moontlike oksidasie deur atmosferiese suurstof (O2) te verhoed. Opgeloste Mn2+ was teen die einde van die eksperiment geekstraëer om enige reduksie van birnessiet waar te neem. Onder N2 is dieselfde produkte as voorheen gevorm, met geen aansienlike Mn2+ produksie nie, aanduidend van 'n nie-oksideerende afbreek van atrasien deur birnessiet. Die laaste deel het die effekte van ultraviolet (UV) straling op die afbreek van atrasien op droëende mineraaloppervlaktes ondersoek. Die UV-straling het atrasien afbreek vermeerder, maar geen ander afbreek-produkte is gevorm nie. Die gevolgtrekking is dus dat atrasien afbreking op redoks-aktiewe mineraal-oppervlaktes verhoog word met drooging, deur 'n netto nie-oksidasie meganisme. Verder is hierdie drooging-geinduseerde afbreking 'n atrasien ontgiftingsmeganisme wat eenvoudig toegepas kan word deur landboupraktyke soos windrying, ploeg en ander praktyke wat (vinnig) 'n Mn- of Fe-oksied ryke landbou grond verdroog.
National Research Foundation (NRF)
4
Teixeira, Alete Paixão. "Determinação de elementos essenciais em arroz empregando espectrometria de fluorescência de raios X de energia dispersiva". reponame:Repositório Institucional da UFBA, 2010. http://www.repositorio.ufba.br/ri/handle/ri/9897.
Testo completoAbstract (sommario):
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CAPES
O objetivo principal do trabalho foi à utilização da espectrometria de fluorescência de raios X com energia dispersiva (EDXRF) para determinação de elementos essenciais, tais como P, Cu, Fe, Mn e Zn em amostras de arroz na forma de pastilhas como método alternativo, obtendo resultados com precisão e exatidão aceitáveis no controle de qualidade dos alimentos. A validação foi feita comparando os resultados obtidos pelo método proposto com valores certificados e com aqueles obtidos utilizando decomposição das amostras em forno de micro-ondas com cavidade e os digeridos foram usados para determinação dos analitos por espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES) e espectrometria de massas com plasma indutivamente acoplado (ICP-MS). A precisão foi avaliada em termos da repetibilidade, sendo que foram preparadas onze pastilhas do material de referência certificado de farinha de arroz 1568a NIST e efetuadas três medições em cada pastilha obtendo-se estimativas do desvio padrão relativo inferiores a 5%. A exatidão foi verificada com o material de referência certificado (farinha de arroz 1568a NIST) e o t-teste pareado revelou que não havia diferença significativa entre os valores certificados e obtidos ao nível de confiança de 95%. Foram obtidos os seguintes limites de detecção (LODs): 0,037 g 100g-1 para P e 1,2; 3,9; 5,1 e 2,2 mg Kg-1 para Cu, Fe, Mn e Zn, respectivamente. O procedimento proposto foi aplicado para P, Mn e Zn e apresenta vantagens tais como a redução do tempo de análise e a eliminação da etapa de decomposição da amostra, porém apresenta a desvantagem dos maiores LODs. De modo geral, os resultados são novas informações sobre a composição mineral do arroz consumido na cidade de Salvador, Bahia, sendo úteis para formação de base de dados.
Salvador
5
Ur, Rehman Bilal. "Modelling a Mineral Froth Flotation Process : Case Study: Minerals process at Boliden AB". Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-51600.
Testo completoAbstract (sommario):
We present an approach to model the dynamic of a copper flotation process. The conventional approach of system identification is applied to model the dynamics. In this research, experiments are performed to collect process data of determined input and output variables. It is followed by data pre-processing to handle outliers and to remove high frequency disturbances. Simulation and validation responses of linear estimated models, which captured the dynamic of the process, are presented. The long term goal is to use estimated models to design a models-based control system.
6
DiFeo, Anthony. "Heterocoagulation of sulphide minerals". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0032/NQ64547.pdf.
Testo completo
7
Higgins, I. "Sialons from natural minerals". Thesis, University of Newcastle Upon Tyne, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375599.
Testo completo
8
Needham, Sarah Jane. "Creatures, fabrics and minerals". Thesis, University of Liverpool, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426129.
Testo completo
9
Duncan, Helen. "Erosion corrosion by minerals". Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278290.
Testo completo
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Rêgo, Eric Siciliano. "Variation of minerals and clay minerals recorded in the Neo-Tethys (central Turkey): new evidence of climatic changes during the middle Eocene". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/21/21136/tde-23032018-152550/.
Testo completoAbstract (sommario):
Minerals and clay minerals in continental sedimentary successions are valuable tools for reconstructing past environmental conditions. Given the state of preservation of clays minerals, it is possible to identify how they were formed, providing clues about continental weathering conditions (inherited minerals) and geochemical conditions in the water column (neoformed or transformed). This study presents new mineralogical data from the Baskil section, a highly preserved middle Eocene succession in the Neo-Tethys (central Turkey). A gradual shift from a well-crystalline illite and chlorite interval (subsection I) to a detrital smectite dominant interval (subsection II) characterizes a change in source area from metamorphic to igneous rocks and changes from physical to chemical weathering conditions on land. This period coincides with the Middle Eocene Climatic Optimum (MECO), indicating a mineralogical signature of the event. Higher content of terrigenous input being deposited from 40.5 to 40 Ma caused a dilution effect of the carbonate materials as calcite and dolomite significantly decreases. Authigenic palygorskite showed an increasing trend from the middle to the uppermost portion of the section, indicating favorable conditions in the water column for its formation. We assume that conditions in the ocean circulation changed after 40 Ma, forming a stratified water column with warmer and saline conditions at greater depths, favoring palygorskite and possibly authigenic dolomite precipitation. The mineralogical evolution of the Baskil section reflects how sources and weathering regimes changed through time, and how these changes can be related to global (i.e. MECO) and/or local to regional processes.Minerais e argilominerais em sucessões sedimentares são excelente ferramentas para a reconstrução de condições ambientais. Dado o estado de preservação dos argilominerais, é possível identificar como eles foram formados, fornecendo informação sobre as condições de intemperismo no continente e sobre condições geoquímicas na coluna d\'água. Este estudo apresenta novos dados mineralógicos da seção de Baskil, uma sucessão do Eoceno médio altamente preservada no Neo-Tethys (Turquia central). Uma mudança na assembléia mineralógica com maiores concentrações de ilita e clorita (subseção I) para um intervalo dominante de esmectita detrítica (subseção II) caracteriza uma mudança na área de fonte de rochas metamórficas para rochas ígneas e mudanças de condições de intemperismo físico para intemperismo químico. Este período coincide com o Ótimo Climático do Eoceno Médio (MECO), indicando uma assinatura mineralógica do evento. A paligorsquita autigênica teve um aumento na porção media e superior da seção, indicando condições favoráveis na coluna de água para a sua formação. Possívelmente as condições na circulação do oceano naquela região mudaram após 40 Ma, formando uma coluna de água estratificada com condições mais quentes e salinas em profundidades maiores, favorecendo precipitação de paligorsquita e dolomita. A evolução mineralógica da seção de Baskil reflete como as fontes e os regimes de intemperismo mudaram ao longo do tempo, e como essas mudanças podem estar relacionadas aos processos globais (e.g. MECO) e /ou a processos locais e regionais.
11
Meirelles, Rodrigo Lemos. "Efeitos da suplementação de antioxidantes naturais em tecidos bovinos da raça Brangus". Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/74/74131/tde-26052009-101756/.
Testo completoAbstract (sommario):
Vinte e oito bovinos machos inteiros da raça Brangus foram utilizados para se determinar os efeitos da estabilidade oxidativa no músculo e no fígado, comparando a utilização de fonte orgânica e inorgânica de selênio e extrato de alecrim, com base na análise da concentração de selênio no fígado e no soro, na análise da atividade da enzima glutationa peroxidase, da enzima superóxido dismutase e da catalase no fígado, e na análise de TBARS (substâncias reativas ao ácido 2-tio-barbitúrico) no músculo. Os tratamentos foram: 1) Controle - sem suplementação de selênio ou de extrato de alecrim; 2) Se IN - 2 mg de selênio/kg de matéria seca na forma de selenito de sódio; 3) Se - 2 mg de selênio/kg de matéria seca, na forma de selênio-metionina; e 4) Alecrim - 1400 mg de extrato de alecrim/kg de matéria seca. O ganho de peso foi maior com a suplementação de selênio inorgânico (P<0,05) em relação ao tratamento controle, mas não apresentou diferença em relação aos outros tratamentos. A eficiência alimentar foi maior em todos os tratamentos quando comparados ao controle (P<0,05). A ingestão de matéria seca não foi alterada pelos tratamentos (P>0,05). A concentração de selênio no fígado foi maior no tratamento selênio inorgânico (P<0,05) do que no tratamento controle, entretanto os tratamentos alecrim e selênio orgânico não apresentaram diferença entre si (P>0,05). A concentração de selênio no soro foi maior nos tratamentos selênio orgânico e inorgânico em relação ao controle por todo o período (P<0,05). O perfil de ácidos graxos na carne não foi alterado pelos tratamentos (P>0,05). A atividade da glutationa peroxidase foi maior no tratamento selênio inorgânico em relação ao controle (P<0,05). A atividade da superóxido dismutase foi menor no tratamento alecrim (P<0,05). Tanto a atividade da enzima catalase quanto a análise de TBARS não apresentaram diferença entre os tratamentos (P>0,05).Twenty eight Brangus males were used to determine the oxidative stability of muscle and liver in order to compare organic and inorganic selenium source and rosemary extract based on the analysis of selenium concentration in the liver and in the serum, on the analysis of glutathione peroxidase, superoxide dismutase and catalase activities in the liver and also based on TBARS analysis (substances related to 2-thiobarbituric acid) in the muscle. Treatments were: 1) Control . without selenium or rosemary extract; 2) Se IN . 2 mg selenium/kg dry matter, as sodium selenite; 3) Se . 2 mg selenium/kg dry matter, as selenium-methionine and 4)Rosemary . 1400 mg rosemary extract/kg dry matter. Weight gain was greater when inorganic selenium was used (P<0.05) in comparison with control, however there was no difference regarding the other treatments. Feed efficiency was higher than control for all treatments (P<0.05). Dry matter intake was not affected by treatments (P<0.05). Selenium concentration in the liver was greater for inorganic selenium (P<0.05) than for control, in spite of that rosemary and organic selenium did not differ between themselves (P<0.05). Selenium concentration in the serum was higher for organic and inorganic selenium treatments than for control during all the period (P<0.05). Fatty acid profile in the meat was not affected by the treatments (P<0.05). Glutathione peroxidase activity was greater for inorganic selenium treatment when compared to control (P<0.05). Superoxide dismutase activity was lower for the rosemary treatment (P<0.05). Neither catalase activity nor TBARS analysis differ among treatments (P<0.05).
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Afonso, Esther Ramalho. "Impacto de estratégias nutricionais no custo do manejo dos dejetos de suínos". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/10/10135/tde-31082015-165733/.
Testo completoAbstract (sommario):
O estudo tem como objetivo propor método de avaliação de efeito econômico do manejo dos dejetos com a utilização de diferentes estratégias nutricionais de suínos em crescimento e terminação. Especificamente, procura-se: i) Calcular as margens de comercialização para as diferentes estratégias nutricionais; ii)Avaliar o efeito econômico das diferentes estratégias nutricionais na excreção e aproveitamento de nutrientes pelos animais; iii) Valorar o consumo de água dos animais; iv) Valorar os dejetos gerados pelos suínos em relação ao seu potencial uso como fertilizante orgânico; v) Avaliar o impacto de cada estratégia nutricional sobre o custo do armazenamento (esterqueira) e uso dos dejetos, e sobre o seu tratamento por biodigestor e posterior utilização; vi) Avaliar a viabilidade econômica dos diferentes sistemas nutricionais e posterior utilização dos dejetos como fertilizante orgânico após tratamento por biodigestor e esterqueira. Os tratamentos a partir dos quais os dados foram obtidos são: T1: Dieta com nível alto de proteína bruta e suplementação mínima de aminoácidos (Dieta Controle); T2: T1 com redução do nível de proteína bruta, mediante a suplementação de lisina, metionina, treonina e triptofano industriais, considerando o conceito de proteína ideal; T3: T1 com a inclusão de 0, 010 (%/kg de dieta) fitase e redução dos teores de cálcio e fósforo da dieta; T4: T1 com a suplementação de 40% de minerais orgânicos (Cu, Zn e Mn) e 50% de minerais inorgânicos; T5: T1 combinando os tratamentos descritos anteriormente. As análises estatísticas foram realizadas utilizando o pacote computacional SAS, com nível de significância de 5%. As características de desempenho zootécnico, peso médio, consumo médio de ração, ganho médio de peso e conversão alimentar e as margens de comercialização não apresentaram diferenças significativas nos diferentes tratamentos e períodos. Os tratamentos T4 e T5 apresentaram melhor eficiência na utilização de nutriente e menor excreção dos nutrientes.Os tratamentos T5 e T4 apresentaram menor consumo e menor custo na valoração da água. A valoração dos dejetos foi favorável ao T1 com maior quantidade de NPK. Os tratamentos ambientalmente mais eficientes apresentaram menores custos na construção da esterqueira e biodigestor em ambos os materiais, PVC e PEAD; os mesmos tratamentos apresentaram menor potencial fertilizante; o caminhão com tanque de 15t apresentou menores custos no transporte e distribuição dos dejetos. Em todos os cenários avaliados dos diferentes sistemas nutricionais e posterior utilização dos dejetos como fertilizante orgânico após tratamento por biodigestor e esterqueira foram viáveis economicamente com payback de um ano. Os métodos ambientais propostos se mostraram válidos, pois foram capazes de identificar que dietas com maior aporte tecnológico apresentaram vantagens frente à dieta controle, entretanto economicamente o T1 apresentou maior quantidade na produção e consequente valoração de NPK.The study aims to propose economic effect evaluation method of manure management with the use of different nutritional strategies of growing and finishing pigs. Specifically, the objectives were: i) To calculate marketing margins for the different nutritional strategies; ii) To evaluate the economic effect of different nutritional strategies on excretion and utilization of nutrients by the animals; iii) Valuing water consumption of animals; iv) Valuing the waste generated by the pigs in relation to its potential use as organic fertilizer; v) Valuing the impact of each nutritional strategy on storage cost (composting) and use of waste products, and about their treatment by bio-digester and later use; and vi) Valuing the economic viability of the different nutritional systems and subsequent use of manure as organic fertilizer after treatment by bio-digester and composting. The treatments from which data were collected were: T1: diet with high level of crude protein and minimum supplementation of amino acids (Control Diet); T2: Diet T1 with a reduction in the level of crude protein by supplementation of lysine, methionine, threonine and tryptophan, assuring the industrial ideal protein of all essential amino acids; T3: T1 with the inclusion of 0.010 phytase (%/kg diet) and reduction of the levels of calcium and phosphorus in the diet; T4: T1 with 40% supplementation of organic minerals (Cu, Zn and Mn) and 50% of inorganic minerals; T5: T1 combining the treatments described previously. Statistical analyses were performed using SAS computing package, with a significance level of 5%. The performance characteristics, average weight, average consumption of rations, average gain of weight and feed conversion and marketing margins showed no significant differences in the treatments and periods. The treatments T4 and T5 showed better efficiency in nutrient utilization and lower nutrient excretion. The T5 and T4 treatments showed lower consumption and lower cost at valuation of water. The valuation of the manure was favorable to T1 with largest amount of NPK. Environmentally efficient treatments showed lower costs in building the composting and biodigester in both materials, PVC and PEAD; the same treatments showed lower potential fertilizer; the tank truck 15 m3 presented lower costs in transportation and distribution of manure. In all scenarios evaluated the different nutritional systems and subsequent use of manure as organic fertilizer after treatment by bio-digester and composting were economically viable with payback of one year. Environmental methods proposed were valid, because they were able to identify that diets with higher technological contribution presented advantages the control diet, however economically the T1 was more quantity in production and consequent valuation of NPK.
13
Gwamba, John. "Pearl millet : influence of mineral biofortification and simple processing technologies on minerals and antinutrients". Diss., University of Pretoria, 2016. http://hdl.handle.net/2263/60808.
Testo completoAbstract (sommario):
Pearl millet is an important staple food in rural Africa. However, the mineral bioavailability of pearl millet is low due to its high content of antinutrients, particularly phytate. This research investigated the effects of mineral biofortification, steeping/lactic acid fermentation and parboiling alone and in combination with abrasive decortication of pearl millet grain on its mineral and antinutrient contents. Six normal varieties and two mineral biofortified hybrids were investigated.
There was considerable variability in mineral content among the varieties. Iron content ranged from 3.0 to 9.6 mg /100 g and zinc from 3.0 to 4.8 mg /100 g. The mineral biofortified hybrids Dhanashakti and ICMH 1201 had substantially higher iron (21-68%) and zinc (15-39%) contents compared to the normal varieties. Phytate content differed substantially, with levels from 830 to 1360 mg /100 g. There was no definite trend between the phytate content of normal and mineral biofortified types.
Decortication did not cause significant losses in zinc, but resulted considerable iron losses (mean 31%) across the varieties. There were minimal effects of steeping/lactic acid fermentation and parboiling on iron and zinc contents. Mineral biofortified hybrids were associated with high iron and zinc content after all processing treatments. Decortication of raw grain substantially reduced phytate (mean 24%) and by a further 12 percentage points when applied after steeping/lactic acid fermentation. Parboiling plus decortication was less effective in reducing phytate content. The critical phytate: iron molar ratio of <1, above which iron absorption is seriously impaired, was not achieved with any of the processes. However, steeping/lactic acid fermentation plus decortication and parboiling plus decortication reduced the phytate: zinc molar ratio to below the critical level of <15 in some varieties. Generally, the mineral biofortified hybrids had improved phytate: mineral molar ratios than the normal varieties for both raw and processed grains. Decortication greatly reduced total phenolic content (mean 24%) across the varieties and by an additional 14 percentage points after steeping/lactic fermentation and parboiling.
Abrasive decortication in combination with steeping/lactic acid fermentation is an effective way of reducing phytate content in pearl millet grain, and hence somewhat improving estimated iron and zinc availability. It is recommended that the process is utilised to a greater extent in pearl millet food processing. Parboiling is also effective in phytate reduction, and can be adopted. Because mineral biofortified pearl millet hybrids have much higher iron and zinc contents, their breeding and cultivation should be promoted in rural Africa.Dissertation (MSc)--University of Pretoria, 2016.
Food Science
MSc
Unrestricted
14
Dydak, Sara M. "The Hydraulic Sorting of Light and Heavy Minerals, Heavy-Mineral Concentrations, and Grain Size". W&M ScholarWorks, 1991. https://scholarworks.wm.edu/etd/1539617625.
Testo completo
15
Lener, Edward F. "Mineral Chemistry of Heavy Minerals in the Old Hickory Deposit, Sussex and Dinwiddie Counties, Virginia". Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/35803.
Testo completoAbstract (sommario):
The Old Hickory is the largest of a series of Pliocene (?) age heavy mineral sand deposits in Virginia and North Carolina. The high density of heavy minerals allows for selective concentration during transport and deposition. Under the right conditions, placers of considerable size can be formed. The elliptically shaped ore body of the Old Hickory Deposit extends in a North - South direction and is approximately 13 km (8 miles) long and up to 2.5 km (1.5 miles) wide, with an average thickness of 6.5 m (20 feet). The deposit lies along the Fall Zone, where a thin wedge of Cenozoic Coastal Plain sediments unconformably overlies the older rocks of the Piedmont.
The principal minerals of economic interest found in the heavy mineral sands at the site are ilmenite (FeTiO3), leucoxene (Fe2-xTi3+xO9+x/2) where x is less than or equal to 2, rutile (TiO2), and zircon (ZrSiO4). An important focus of this study is the alteration of ilmenite by leaching away of iron, which results in enrichment in titanium. Titanium metal is highly valued for its light weight and high strength. In terms of total economic value, however, the use of titanium dioxide pigments for paint, coated paper, and other products is far more important. As the value of the ore is heavily dependent on the titanium content, the weathering process is a matter of considerable interest to the mineral industry.
Analysis of ilmenite grains using reflected light microscopy revealed a wide range of alteration textures. Quantitative analysis and mapping of trace elements showed altered areas with enrichment in Ti and depletion in Fe, Mn, Mg, and Cr. It is believed that the weathering process took place in a reducing environment prior to final deposition according to the reaction:
-
Fe2+TiO3 + 2H+ --> Fe2+ (aq) + TiO2 + H2O
Master of Science
16
Kotler, Julia Michelle. "Biosignature storage in sulfate minerals- synthetic and natural investigations of the jarosite group minerals". The University of Montana, 2009. http://etd.lib.umt.edu/theses/available/etd-08062009-143516/.
Testo completoAbstract (sommario):
The discovery of jarosite on Mars in 2004 generated increased interest in the properties of the mineral related to the search for life on other planets. Several studies indicate that the formation of jarosite can be linked to biological activity on Earth and biomolecules such as amino acids have been found associated with terrestrial jarosite samples. A series of natural and synthetic investigations using different jarosite end-members has been conducted and is presented in this dissertation to investigate the possibility that jarosite can store biosignatures. Natural samples were analyzed by x-ray diffraction, elemental carbon analysis and laser-desorption Fourier transform mass spectrometry (LD-FTMS) and were found to contain the amino acid glycine. Synthetic experiments were conducted in which the different end-members were synthesized in the presence of glycine as well as the amino acid alanine and the amino acid breakdown product methylamine. These samples were analyzed by x-ray diffraction, neutron diffraction, LD-FTMS and thermogravimetric analysis (TGA) techniques. Results of these experiments show that the detection of the biosignature and the effect that biomolecule has on the jarosite minerals is dependent on the end-member and indicate that the jarosite minerals are an excellent target for detecting potential signs of past life on other planets.
17
Silva, Rafael Cipriano da. "Intemperismo de minerais de um remineralizador". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-01082016-171821/.
Testo completoAbstract (sommario):
A remineralização é uma prática antiga que está associada a aplicação de pós de rocha no solo visando a melhoria das propriedades edáficas e por fim o aumento da produtividade, associado também a redução dos custos de produção, uma vez que os remineralizadores possuem menor preço comparado com fertilizantes sintéticos solúveis. Porém ainda existem divergências nos resultados obtidos com o uso de remineralizadores, por vezes associados a dificuldade na descrição e controle dos fatores que podem interferir no processo, como clima, características do solo e do remineralizador empregado. Esta tese tem por objetivo investigar a dissolução de um remineralizador em experimentos em diferentes níveis de complexidade e avaliar as alterações mineralógicas correspondentes, inclusive com ênfase na possibilidade de neoformação de minerais. No experimento in vitro foi possível identificar os efeitos do tamanho das partículas e dos diferentes solventes na dissolução dos minerais do remineralizador. Aumentando o nível de complexidade, no experimento em colunas contendo solo, foi possível identificar principalmente um incremento nos teores de Ca+2, Mg+2, K+ trocáveis no solo, além do Na+, Fe e Si no tratamento com a aplicação do remineralizador. Também houve aumento dos teores de Fe e Al extraídos em solução de ditionito-citrato-bicarbonato e oxalato de amônio e, em concordância com os diagramas de estabilidade termodinâmica dos minerais, foi constatada a precipitação de óxidos de baixa cristalinidade no tratamento com remineralizador. No experimento em vasos, a presença das plantas atuou como um dreno, mas mesmo assim com aumento principalmente dos teores de Ca+2 e Mg+2 trocáveis, mas sem ser constatada a precipitação de óxidos amorfos. Por fim, o experimento de campo reafirma o que foi observado nos dois experimentos anteriores, no qual houve aumento dos teores de Ca+2, Mg+2, Na+ e Si trocáveis. Em todos os níveis de experimentos, de forma geral, foi possível observar a maior contribuição de plagioclásios cálcio-sódicos e clinopiroxênios no fornecimento de Ca+2 e Mg+2, principalmente, além de Na+, ferro e silício.The remineralization is an ancient practice of application of rock powders into the soil in order to improve the soil properties and increase productivity. It is also associated with the reduction of production costs, since remineralizers are cheaper as compared to soluble synthetic fertilizers. Contradiction among the results obtained from the use of remineralizadores frequently be associated with difficulty to describe and control of the factors that may affect the results, such as climate, soil characteristics and characterization of the remineralizers used. This thesis aims to investigate the dissolution of remineralizers in experiments with increasing levels of complexity and evaluate the mineralogical changes, emphasing the possibility of neoformation minerals. In the in vitro experiment, it was possible to identify the effects of particle size and different solvents in the dissolution of the mineral presents in the remineralizer. The rock powder when applied in columns containing soil allowed to identify an increase in Ca+2, Mg+2, K+ exchangeable, including Na+, Fe and Si. Also increased the levels of Fe and Al extracted solution of sodium dithionite-citrate-bicarbonate, ammonium oxalate and in accordance with the thermodynamic stability diagrams of minerals, the precipitation of low crystallinity oxide in remineralizer treatment. In the pot experiment, the presence of plants acted as a drain, but there was still an increase of Ca+2 and Mg+2 exchangeable, specially, but without was observed precipitation of amorphous oxides. Finally, field experiment confirms what was observed in the two previous experiments in which there was an increase in Ca+ 2, Mg+ 2, Na+ and Si exchangeable. At all experiments, in general, we observed the greatest contribution of plagioclase and clinopyroxenes in providing of Ca+2 and Mg+2 in large amount, as well as Na+, Fe and Si in minor quantity.
18
Bachmaf, Samer. "Uranium sorption on clay minerals". Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2010. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-62404.
Testo completoAbstract (sommario):
The objective of the work described in this thesis was to understand sorption reactions of uranium occurring at the water-clay mineral interfaces in the presence and absence of arsenic and other inorganic ligands. Uranium(VI) removal by clay minerals is influenced by a large number of factors including: type of clay mineral, pH, ionic strength, partial pressure of CO2, load of the sorbent, total amount of U present, and the presence of arsenate and other inorganic ligands such as sulfate, carbonate, and phosphate. Both sulfate and carbonate reduced uranium sorption onto IBECO bentonite due to the competition between SO42- or CO32- ions and the uranyl ion for sorption sites, or the formation of uranyl-sulfate or uranyl-carbonate complexes. Phosphate is a successful ligand to promote U(VI) removal from the aqueous solution through formation of ternary surface complexes with a surface site of bentonite.
In terms of the type of clay mineral used, KGa-1b and KGa-2 kaolinites showed much greater uranium sorption than the other clay minerals (STx-1b, SWy-2, and IBECO montmorillonites) due to more aluminol sites available, which have higher affinity toward uranium than silanol sites. Sorption of uranium on montmorillonites showed a distinct dependency on sodium concentrations because of the effective competition between uranyl and sodium ions, whereas less significant differences in sorption were found for kaolinite. A multisite layer surface complexation model was able to account for U uptake on different clay minerals under a wide range of experimental conditions. The model involved eight surface reactions binding to aluminol and silanol edge sites of montmorillonite and to aluminol and titanol surface sites of kaolinite, respectively. The sorption constants were determined from the experimental data by using the parameter estimation code PEST together with PHREEQC. The PEST- PHREEQC approach indicated an extremely powerful tool compared to FITEQL.
In column experiments, U(VI) was also significantly retarded due to adsorptive interaction with the porous media, requiring hundreds of pore volumes to achieve breakthrough. Concerning the U(VI) desorption, columns packed with STx-1b and SWy-2 exhibited irreversible sorption, whereas columns packed with KGa-1b and KGa-2 demonstrated slow, but complete desorption. Furthermore, most phenomena observed in batch experiments were recognized in the column experiments, too.
The affinity of uranium to clay minerals was higher than that of arsenate. In systems containing uranium and arsenate, the period required to achieve the breakthrough in all columns was significantly longer when the solution was adjusted to pH 6, due to the formation of the uranyl-arsenate complex. In contrast, when pH was adjusted to 3, competitive sorption for U(VI) and As(V) accelerated the breakthrough for both elements.
Finally, experiments without sorbing material conducted for higher concentrations of uranium and arsenic showed no loss of total arsenic and uranium in non-filtered samples. In contrast, significant loss was observed after filtration probably indicating the precipitation of a U/As 1:1 phase.
19
Crawford, R. J. "Interparticle forces in clay minerals". Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291033.
Testo completo
20
Humes, R. "Interparticle forces in clay minerals". Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370276.
Testo completo
21
Hjeltström, Anna. "Copper minerals under the microscope". Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-243049.
Testo completoAbstract (sommario):
From many perspectives copper is a very important metal for the modern society. It can be found in everything from jewellery to electronics. For this reason it is very important for geologists to be able to develop efficient methods for identification, characterisation, extraction and processing of copper. One method for the identification of copper bearing minerals is ore microscopy which has been used in this paper along with a general introduction. Samples from the study collection of the Department of Earth Sciences and the area of Långban and Månhöjden have been examined, documented and described in detail. The thesis begins with an introduction to the history and geochemistry of copper along with some ore forming processes.
22
Nawasreh, Mohammed Khair Assa'd. "Investigations of Jordanian industrial minerals". Thesis, Cardiff University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365618.
Testo completo
23
Oganov, Artem Romaevich. "Computer simulation studies of minerals". Thesis, University College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271656.
Testo completo
24
Koga, Kenneth Tadao 1969. "Kinetic processes of mantle minerals". Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/69187.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Joint Program in Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), February 2000."September 1999."
Includes bibliographical references.
This dissertation discusses the experimental results designed to constrain the processes of MORB generation. The main focus of this study is to investigate the location and the related processes of the transformation boundary from spinel to garnet peridotite facies at subsolidus conditions, because the presence of garnet in melting residues has significant influence to the conclusion drawn from geochemical/geophysical observations. Using an approach that monitors the rate of reaction progresses, the experimental results confirmed the presence of a region that garnet and spinel coexist in peridotite compositions. The trace element distribution among the product phases (opx and cpx) subsequent to the garnet breakdown reaction is in disequilibrium, due to the differences of diffusivity between major and trace elements. The presence of disequilibrium distribution in nature may be used to infer time scales of geodynamic processes. Diffusion coefficients of Al in diopside are experimentally determined, and used for modeling the equilibration of major elements in pyroxene during MORB genesis. In summary, this dissertation contributes two major inferences: the location of the transformation boundaries of the garnet-spinel peridotite; the presence of disequilibrium trace elements distribution with equilibrium major elements distribution in mantle pyroxenes.
by Kenneth Tadao Koga.
Ph.D.
25
Bahri-Esfahani, Jaleh. "Fungal transformation of phosphate minerals". Thesis, University of Dundee, 2014. https://discovery.dundee.ac.uk/en/studentTheses/944bbfa4-4899-429c-be2b-b057d2d10773.
Testo completo
26
Morrison, Shaunna M., e Shaunna M. Morrison. "Crystal Chemistry of Martian Minerals". Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/625376.
Testo completoAbstract (sommario):
The NASA Mars Science Laboratory (MSL) rover, Curiosity, began exploring Gale crater, Mars in August, 2012 with the primary goal of assessing the past and present habitability of the martian surface. To meet this goal, Curiosity is equipped with an advanced suite of scientific instruments capable of investigating the geology, geochemistry, and atmospheric conditions on Mars. Among these instruments is the CheMin (Chemistry and Mineralogy) X-ray diffractometer whose function is to identify mineral phases present in sediments and rocks by means of X-ray diffraction (XRD).
Characterizing the mineralogical make-up of a rock unit is an important step in determining its geologic history. Primary igneous minerals, such as feldspar, olivine, and pyroxene, give information about parental magmas - their composition, temperature, depth and so on. Secondary alteration minerals, like jarosite or akaganeite, point to distinct weathering or diagenetic processes. As such, understanding the mineral occurrence and abundance in Gale crater provides the MSL team with a robust foundation from which to make geologic interpretations.
This dissertation details the methods used to determine the chemical composition of selected mineral phases based solely on XRD patterns from CheMin. Curiosity is equipped with instruments capable of measuring bulk composition of a sample [e.g., APXS (Alpha Particle X-ray Spectrometer)] but has no instrument capable of measuring the composition of a single phase in a multi-phase sample. Therefore, we developed crystal chemical algorithms and calibrations based on refined unit-cell parameters in order to predict mineral phase compositions. We have calculated algorithms for plagioclase, alkali feldspar, Mg-Fe-Ca clinopyroxene, Mg-Fe orthopyroxene, Mg-Fe olivine, Fe-oxide spinel, and alunite-jarosite group minerals. Furthermore, we use the estimated compositions of crystalline material in conjunction with bulk sample chemistry from APXS to estimate of the composition of the X-ray amorphous material present in each of the samples analyzed by CheMin in Gale crater.
27
Down, Sarah. "Māori and Minerals: Debating Rights". Phd thesis, Canberra, ACT : The Australian National University, 2018. http://hdl.handle.net/1885/149166.
Testo completoAbstract (sommario):
The last decade has seen the government in Aotearoa New Zealand place greater economic focus on exploiting mineral resources. As a result, the matter of Māori rights and interests in relation to these resources is of increased relevance and has become a highly charged national issue. The Waitangi Tribunal (‘Tribunal’) has released a number of reports since 1991 that discuss and make recommendations on Māori rights in relation to various mineral resources including pounamu (greenstone), petroleum and gold. This thesis critically analyses the jurisprudence and associated discourse developed by the Tribunal regarding Māori rights and interests in relation to minerals. The Tribunal’s reports are currently underexplored, yet are vital to understanding the issues, complexities and obstacles associated with claims to mineral rights, not only for Māori but for other Indigenous peoples. This is because the inconsistent approaches and recommendations produced by the Tribunal highlight different ways in which arguments about Māori rights in relation to minerals can be conceived and constructed. The core focus of this thesis is on identifying the legal arguments by which Māori claims to minerals rights in each of the Tribunal reports have been considered, recognised, limited, and/or transformed. This thesis then analyses how the Crown responded to the Tribunal’s reports, and how the Crown and iwi have engaged with each other and the Tribunal over the matter of mineral rights through the Treaty settlement process and the review and subsequent amendment of the primary legislation governing minerals, the Crown Minerals Act 1991 (CMA). In so doing, this thesis provides a picture of Māori rights in relation to minerals, and highlights the unresolved issues between Māori and the Crown through the lens of the Tribunal and its discourse.
28
Martens, Wayde Neil. "The vibrational spectroscopy of minerals". Thesis, Queensland University of Technology, 2004. https://eprints.qut.edu.au/15940/1/Wayde_Martens_Thesis.pdf.
Testo completoAbstract (sommario):
This thesis focuses on the vibrational spectroscopy of the aragonite and
vivianite arsenate minerals (erythrite, annabergite and hörnesite), specifically the
assignment of the spectra. The infrared and Raman spectra of cerussite have been
assigned according to the vibrational symmetry species. The assignment of satellite
bands to 18O isotopes has been discussed with respect to the use of these bands to the
quantification of the isotopes. Overtone and combination bands have been assigned
according to symmetry species and their corresponding fundamental vibrations. The
vibrational spectra of cerussite have been compared with other aragonite group
minerals and the differences explained on the basis of differing chemistry and crystal
structures of these minerals.
The single crystal spectra of natural erythrite has been reported and compared
with the synthetic equivalent. The symmetry species of the vibrations have been
assigned according to single crystal and factor group considerations. Deuteration
experiments have allowed the assignment of water vibrational freque ncies to discrete
water molecules in the crystal structure. Differences in the spectra of other vivianite
arsenates, namely annabergite and hörnesite, have been explained by consideration of
their differing chemistry and crystal structures.
A novel approach to the assignment of site occupancy of ions in the erythrite -
annabergite solid solution has been reported. This approach has utilised vibrational
spectroscopy, in conjunction with careful consideration of the crystal structures of the
minerals. It has been shown that in the erythrite - annabergite solid solution Coprefers metal site 2 contrasting nickel which prefers site 1. This study in conjunction
with other studies has yielded the trend that the more electronegative metal prefers to
occupy site 1, with the least electronegative metal preferring to occupy site 2.
Fundamentally this thesis has increased the knowledge base of the
spectroscopic properties of the aragonite and the vivianite minerals. The site
occupancy of metal ion substitutions in solid solution series of the vivianite group of
minerals has been further enhanced, with novel method of studying the site occupancy
of ions in solid solutions has been developed. A detailed knowledge and
understanding of factor group analysis applied to the study of minerals has been
achieved.
29
Martens, Wayde Neil. "The vibrational spectroscopy of minerals". Queensland University of Technology, 2004. http://eprints.qut.edu.au/15940/.
Testo completoAbstract (sommario):
This thesis focuses on the vibrational spectroscopy of the aragonite and vivianite arsenate minerals (erythrite, annabergite and hörnesite), specifically the assignment of the spectra. The infrared and Raman spectra of cerussite have been assigned according to the vibrational symmetry species. The assignment of satellite bands to 18O isotopes has been discussed with respect to the use of these bands to the quantification of the isotopes. Overtone and combination bands have been assigned according to symmetry species and their corresponding fundamental vibrations. The vibrational spectra of cerussite have been compared with other aragonite group minerals and the differences explained on the basis of differing chemistry and crystal structures of these minerals. The single crystal spectra of natural erythrite has been reported and compared with the synthetic equivalent. The symmetry species of the vibrations have been assigned according to single crystal and factor group considerations. Deuteration experiments have allowed the assignment of water vibrational freque ncies to discrete water molecules in the crystal structure. Differences in the spectra of other vivianite arsenates, namely annabergite and hörnesite, have been explained by consideration of their differing chemistry and crystal structures. A novel approach to the assignment of site occupancy of ions in the erythrite - annabergite solid solution has been reported. This approach has utilised vibrational spectroscopy, in conjunction with careful consideration of the crystal structures of the minerals. It has been shown that in the erythrite - annabergite solid solution Coprefers metal site 2 contrasting nickel which prefers site 1. This study in conjunction with other studies has yielded the trend that the more electronegative metal prefers to occupy site 1, with the least electronegative metal preferring to occupy site 2. Fundamentally this thesis has increased the knowledge base of the spectroscopic properties of the aragonite and the vivianite minerals. The site occupancy of metal ion substitutions in solid solution series of the vivianite group of minerals has been further enhanced, with novel method of studying the site occupancy of ions in solid solutions has been developed. A detailed knowledge and understanding of factor group analysis applied to the study of minerals has been achieved.
30
Balfagón-Romeo, Aitor. "Nutritional approach to mineral over-supplementation in grow-finish pigs : organic trace minerals and phosphorus body accretion". Lexington, Ky. : [University of Kentucky Libraries], 2006. http://lib.uky.edu/ETD/ukyansc2006t00463/ABalfagon.pdf.
Testo completoAbstract (sommario):
Thesis (M.S.)--University of Kentucky, 2006.Title from document title page (viewed on August 22, 2006). Document formatted into pages; contains: x, 99 p. : ill. (some col.). Includes abstract and vita. Includes bibliographical references (p. 90-98).
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Tibiriçá, Luciana Gonçalves. "Aspectos econômicos e sociais da mineração em Goiás, com ênfase na extração de areia". Universidade Federal de Goiás, 2017. http://repositorio.bc.ufg.br/tede/handle/tede/7584.
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The State of Goiás (Brazil) has in the mining activity a relevant source of gathering funds and which is part of its history of occupation and formation of urban networks. The mining activity is administrated by technical criteria defined by the Brazilian Department of Mining Production (as known as DNPM), being environmental licensing a part that integrates them. With the pointed requirements on the environmental legislation, the formal mining exploration has adapted itself in front of the need of conserve/preserve the environment considering the geological and geographical conditions. Present in several industries, the use of mineral resources allows the development of varied goods, moving finance market and creating jobs. From the principles that mining is an activity of wide economic impact, involves environmental problems and that the mining activity of the State of Goiás needs deep researches of characterization, we developed this thesis. The assessment of the several mineral was made by the employment of a methodology in municipal scale, from those with major revenue arising from the mineral compensation due to the extraction of metallic minerals or non metallic more profitable currently for Goiás, beyond the sand considering the period between 2010 and 2014. The results show that in the social aspect, the difference between the main mining municipalities of Goiás is not relevant, even with the contribution from the mineral compensation. For the municipalities producers of sand, the economic impact is minimum and there are difficulties in following the recuperation of degraded areas, because the resource is not enough to enable the manager the actions of local development.
O Estado de Goiás tem na mineração uma fonte de arrecadação relevante e que faz parte de sua história de ocupação e formação das redes urbanas. A atividade mineral é administrada por critérios técnicos definidos pelo Departamento Nacional da Produção Mineral (DNPM), sendo que o licenciamento ambiental é parte integrante dos mesmos. Com as exigências apontadas nas legislações ambientais, a exploração mineral formal tem se adaptado frente à necessidade de conservar/preservar o ambiente considerando as condições geológicas e geográficas. Presente em diversas indústrias, o uso dos recursos minerais permite o desenvolvimento de produtos variados, movimentando o mercado financeiro e gerando emprego. A partir dos princípios de que a mineração é uma atividade de amplo impacto econômico, envolve problemas ambientais e que a mineração goiana necessita de pesquisas de caracterização mais aprofundadas, desenvolveu-se esta tese. Para avaliação dos diversos minérios empregou-se uma metodologia em escala municipal, a partir daqueles com maior receita oriunda da compensação mineral decorrente da extração de minérios metálicos ou não metálicos mais rentáveis atualmente para Goiás, além da areia considerando o período entre 2010 e 2014. Os resultados obtidos demonstram que no aspecto social, a diferença entre os principais municípios mineradores de Goiás não é relevante, apesar do aporte advindo da compensação mineral. Para os municípios produtores de areia, o impacto econômico é mínimo e há dificuldades em acompanhar a recuperação das áreas degradadas, pois o recurso não é suficiente para possibilitar ao gestor as ações de desenvolvimento local.
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Jones, Alison. "Ionic mobility in stuffed-silica minerals". Thesis, Open University, 2000. http://oro.open.ac.uk/19720/.
Testo completoAbstract (sommario):
Using a combination of dielectric spectroscopy and atomistic computer simulation techniques, the dynamical behaviour of loosely bound cations in the stuffed-silica minerals nepheline, yoshiokaite and ß-eucryptite has been investigated. The investigation has been extended to include the feldspar minerals albite, K-feldspar and anorthite. The low-frequency dielectric properties of all of the minerals have been investigated from room temperature to 1100 K. At each temperature, the dielectric constant, conductivity and dielectric loss were determined over a range of frequencies from 100 Hz to 10 MHz. At high temperatures distinct Debye-type relaxation processes were observed, from which activation energies were determined for each system studied. In order to rationalise these data, in the context of actual ionic mobility mechanisms, atomistic simulation.- techniques were used to elucidate the mechanisms and energetics of cation migration. Good correlation between experimentally determined and calculated energy barriers has been demonstrated. The results obtained from computer modelling confirm the nature of the processes responsible for the observed dielectric behaviour. Furthermore, they reveal the importance of framework relaxation effects in the facilitation of ion migration within a structure. This study demonstrates that short-range ionic mobility in framework silicates can be described using conventional (Debye-type) activated "hopping" models. A detailed interpretation of the mechanism of these processes has been possible by a combination of dielectric spectroscopy and computer modelling techniques. By applying the methods used here to a variety of mineral systems, it should be possible to develop a comprehensive body of transferable data relating structural aspects of framework minerals to the systematic prediction of ion migration mechanisms and energetics.
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Cumbane, Antonio Jose. "Microwave treatment of minerals and ores". Thesis, University of Nottingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396800.
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Mookherjee, Mainak. "Order-disorder in hydrogen-bearing minerals". Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619612.
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Myers, Eva Rebecca. "Al/Si ordering in silicate minerals". Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624192.
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Jakeways, Claire Vanessa. "Transformation-induced anelasticity in mantle minerals". Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611868.
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Araizi, Paris-Kavalan. "Accelerated carbonation of wastes and minerals". Thesis, University of Greenwich, 2015. http://gala.gre.ac.uk/21536/.
Testo completoAbstract (sommario):
Accelerated carbonation technology (ACT) could be used for the stabilisation of hazardous wastes, remediation of contaminated soils and re-use/recycling of various waste streams. ACT has also potential for storing anthropogenic CO2 emissions into mineral silicates and alkaline waste residues via mineral or waste carbonation. Compared to ocean and geological storage, mineral and waste carbonation offer several advantages such as long-term storage and low monitoring requirements. Currently, the biggest challenge of mineral carbonation is the low conversion rate of calcium and magnesium-based minerals into thermodynamically stable carbonates under ambient temperature and pressure. Also, literature offers little information about physical techniques or chemical substances that could enhance the efficacy of accelerated carbonation of alkaline wastes. In this study, various carbonation techniques were applied for increasing the carbonation reactivity of magnesium hydroxide. The experiments were conducted under low temperature and pressure, while the maximum reaction time was 24 hours. Under these conditions the associated costs are kept to a minimum. The possibility of producing monolithic products with value-added was investigated by using blended mixtures of magnesium and calcium hydroxide. These mixtures were cured in carbon dioxide for 7 and 28 days and their physical properties were measured and compared with the properties for normal and lightweight concrete. Moreover, several alkaline residues were carbonated with the aid of ultrasound and four candidate catalysts (acetic acid, ethanol, sodium hypochlorite and sodium nitrite) and their CO2 uptake was measured. During sonication the variables: ultrasonic frequency, water content and treatment time were examined, while the applied chemicals were added at three different molarities (0.1 M, 0.5M and 2.5M). Throughout this work a number of analytical techniques were used for the characterisation of the raw and carbonated materials. These techniques included XRay fluorescence, X-ray diffraction, wet laser analysis, total organic carbon analysis and scanning electron microscopy. The results showed that the CO2-reactivity of Mg(OH)2 was low due to thermodynamic constraints that inhibited the rapid diffusion of CO2 into the system. The mixtures composed of pure Mg showed improved compressive strength and bulk density. In addition, sonication at low water content was weak, as there was lack of enough water to facilitate cavitation. On the other hand, at high water content the achieved CO2 uptake of the products increased by up to four times, as the wet conditions enhanced the cavitation of the solid particles. Finally, it was found that ethanol and acetic acid promoted the hydration rate of CO2 during accelerated carbonation, while minerals phase analysis did not reveal the formation of toxic by-products. In conclusion, the findings of this study proved that sonication depends highly on water content and is favoured at wet conditions. Furthermore, acetic acid and ethanol are two chemicals with potential to ameliorate the accelerated carbonation of various industrial wastes without the formation of un-desired or toxic compounds.
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Xu, Yuping. "Interactions of heavy metals with minerals /". The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487856076412928.
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Cymes, Brittany Allison. "Catalytic Properties of Novel Microporous Minerals". Miami University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=miami1587730697926361.
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Richardson, Stephen. "Sulphide ore minerals : surface chemical properties". Thesis, Aston University, 1988. http://publications.aston.ac.uk/8068/.
Testo completoAbstract (sommario):
The surfaces of iron-containing sulphide minerals were oxidised by a range of inorganic oxidants, and the resultant surface alteration products studied using various spectroscopic techniques. The characterisation of surface oxidation is relevant to the alteration of ores in nature and their behaviour during flotation and leaching, of importance to the metallurgical industry. The sulphides investigated included pyrite (FeS2), hexagonal pyrrhotine (Fe9S10), monoclinic pyrrhotine (Fe7Se), violarite (FeNi2S4), pentlandite ((FeiNi)9Se), chalcopyrite (CuFeS2) and arsenopyrite (FeAsS). The surfaces were oxidised by various methods including acid (sulphuric), alkali (ammonium hydroxide), hydrogen peroxide, steam, electrochemical and air/oxygen (in a low-temperature (150ºC) furnace), The surfaces were examined using surface sensitive chemical spectroscopic methods including x-ray photoelectron spectroscopy (ms), Auger electron spectroscopy (LES) and conversion electron Mössbauer spectroscopy (CEKS). Physical characterisation of the surfaces was undertaken using scanning electron microscopy (SM), spectral reflectance measurements and optical microscopy. Bulk characterisation of the sulphide minerals was undertaken using x-ray diffraction and electron microprobe techniques. Observed phases suggested to form in most of the sulphide surfaces include Fe204, Fe1-x0, Fe202, Fe00H, Fe(OH)3, with iron II & III oxy-sulphates. The iron sulphides show variable extents of oxidation, indicating pyrite to be the most stable. Violarite shows stability to oxidation, suggested to result from both its stable spinel crystal structure, and from the rapid formation of sulphur at the surface protecting the sub-surface from further oxidation. The phenomenon of sub-surface enrichment (in metals), forming secondary sulphides, is exhibited by pentlandite and chalcopyrite, forming violarite and copper sulphides respectively. The consequences of this enrichment with regard to processing and leaching are discussed. Arsenopyrite, often a hindrance in ore processing, exhibits the formation of arsenic compounds at the surface, the dissolution of which is discussed in view of the possible environmental hazard caused by the local pollution of water systems. The results obtained allow a characterisation of the sulphides in terms of their relative stability to oxidation, and an order of stability of the sulphide surfaces is proposed. Models were constructed to explain the chemical compositions of the surfaces, and the inter-relationships between the phases determined at the surface and in the sub-surface. These were compared to the thermo-chemically predicted phases shown in Eh/pH and partial pressure diagrams! The results are discussed, both in terms of the mineralogy and geochemistry of natural ores, and the implications for extraction and processing of these ore minerals.
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Ahmad, Mushtaque. "Persulfate activation by major soil minerals". Pullman, Wash. : Washington State University, 2008. http://www.dissertations.wsu.edu/Thesis/Fall2008/m_ahmad_032409.pdf.
Testo completoAbstract (sommario):
Thesis (M.S. in environmental engineering)--Washington State University, December 2008.Title from PDF title page (viewed on Apr. 17, 2009). "Department of Civil and Environmental Engineering." Includes bibliographical references (p. 15-18).
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Jones, Alison. "Ionic mobility in stuffed-silica minerals". n.p, 2001. http://library7.open.ac.uk/abstracts/page.php?thesisid=49.
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Gillings, Hayley S. "Surface-modified minerals for radionuclide sequestration". Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/33781.
Testo completoAbstract (sommario):
This thesis is concerned with experiments designed to identify materials to increase the utility of the Sellafield Ion Exchange Plant (SIXEP) process. Clinoptilolite, ZSM-5, vermiculite and kaolinite have been surface modified by grafting with APTES, TMSPE and TMSPETT ligands using varying grafting times (1-24 h), ligand concentrations (1-3 mmol) and solvents with different polarities (with dielectric constant between 1.9 80). Materials before and after grafting were analysed using long and short range techniques including elemental analysis (CHN), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), solid state nuclear magnetic resonance (SSNMR) and infra-red (FTIR) spectroscopy. The amount of graft placed on the surface increased with reaction time for all materials as the amount of carbon per unit mass of the support, determined by CHN analysis, increased with time. C-H stretches were consistently observed in the FTIR of the grafted materials but no change was observed to the long range order in the PXRD pattern. 13C SSNMR showed that small solvent molecules such as acetone can become trapped in the material supports during grafting and long drying times are required to ensure that trapped solvent molecules do not contaminate the CHN analyses of the materials after grafting. Clinoptilolite and vermiculite consistently achieved higher grafting levels than ZSM-5 or kaolinite, with clinoptilolite (NDA) showing the greatest carbon content of 56.16 mmol of APTES per gram of clinoptilolite using hexane as the solvent. Despite a similar molecular weight, TMSPE consistently showed lower levels of grafting than APTES. APTES grafting levels were increased by using citric, phosphoric and nitric acid (1-3 mol L-1) to pre-treat the surface of the materials over different time periods (1-24 h) to improve the level of APTES graft. While the carbon content was higher for acid treated clinoptilolite (NDA) after grafting, in the case of the citric acid treatment, this increase maybe due to the formation of iron (III) citrate from the dissolution of poorly crystalline iron impurities in the clinoptilolite (NDA). Ungrafted and grafted clinoptilolite, ZSM-5, vermiculite and kaolinite samples were investigated for their ability to sequester caesium, strontium, uranium and plutonium species. Absorption/desorption experiments were initially conducted on the ungrafted compounds using caesium and strontium cations to establish a baseline for the most abundant species in pond liquor. Caesium and strontium cations are trapped within the cages of clinoptilolite in an ion exchange reaction which places these ions on sites of the appropriate size and geometry for these species. Once ion exchanged, neither ion is desorbed from the clinoptilolite readily and they remain trapped inside the cage, irrespective of concentration of other species in solution. While vermiculite is also successful at removing both caesium and strontium cations, it is less successful in retaining them during desorption, with typically one third of the trapped ions being released back into solution. ZSM-5 and kaolinite have contrasting behaviour, due to few exchangeable cations, meaning caesium and strontium uptake is poor. Samples of clinoptilolite with different particle sizes and potassium content were compared and showed that smaller particles facilitated faster exchange. Grafting had a variable effect on the caesium/strontium cation uptake and release during absorption/desorption presumably as a result of the donors on grafted ligand interacting weakly with the large cations. Experiments using distilled water and synthetic liquor (carbonated sodium hydroxide), demonstrated uranium and plutonium species were extracted by all materials after grafting at concentrations in the SIXEP range. The most successful ligand/graft combination for plutonium at pH 7 was APTES grafted on clinoptilolite (10.79% carbon).
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Kapitulcinova, Dana. "Cyanobacteria-mineral interactions : Laboratory investigation on the colonisation and weathering of common phosphate and silicate minerals". Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520234.
Testo completo
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Gimeno, Torrente Domingo. "Estudio geológico y metalogenético de los materiales de la cuenca paleozoica de la región del Sarrabus". Doctoral thesis, Universitat de Barcelona, 1989. http://hdl.handle.net/10803/669668.
Testo completoAbstract (sommario):
Este trabajo de tesis forma parte de una colaboración de carácter internacional entre el Departamento de Geoquímica, Petrologia y Prospección Geológica de la Universidad de Barcelona y el lstituto di Giacimenti Minerari (IGM) della Facoltà di Ingegneria dell ‘Università di Cagliari, Italia. Hasta el momento en que se decidió emprender emprender este trabajo (finales de 1982), una de las principales líneas de investigación consistía en la prospección, estudio y valoración de los recursos metálicos de Cataluña, gracias a una extensa campaña de exploración geoquímica y mineralógica que perseguía aportar criterios geológicos y yacimentológicos válidos para su interpretación. Por su parte nuestros colegas italianos del IGM acababan de concluir un extenso estudio sobre las posibilidades mineras del centro de Cerdeña y estaban interesados en proseguir dichos estudios en el SE de la isla. Por todo ello se decidió escoger la región del Sarrabus como sector piloto en el que concentrar la mayor parte de la investigación de la tesis.
La mayor parte del trabajo de tesis se ha desarrollado en la región del Sarrabus. En esta zona se han cartografiado unos 325 Km2 de materiales de la cuenca paleozoica a escala 1:10.000, se han desarrollado los estudios sedimentológicos, petrológicos y de paleovulcanismo, se ha reconstruido la cuenca sedimentaria existente durante el Ordovícico Superior, el Silúrico y el_ Devónico, se han estudiado en detalle las diferentes mineralizaciones y se han elaborado los diferentes modelos de yacimientos.
La tesis se inicia con una primera parte que contiene apartados referidos a las principales litologías estudiadas en detalle desde un punto de vista sedimentológico, petrológico y petrográfico. Se describe y comenta la geología del Sarrabus empleando una subdivisión en cinco zonas, se procede a la integración de los datos, se analizan algunos de los cortes geológicos más significativos y se procede a extraer las conclusiones generales obtenidas en la reconstrucción de la cuenca a la luz de la cartografía geológica realizada. A continuación, en la segunda parte, se efectúa una recopilación de la información disponible, con un interés especial por las mineralizaciones de los modelos geológicos previamente establecidos en el Sarrabus. La tercera parte analiza la mayor cantidad de datos posibles, reinterpretando algunos sectores ya conocidos y proponiendo criterios para realización de nuevos trabajos en los mismos.
A la hora de redactar esta memoria, se ha perseguido que cada capítulo tuviera entidad propia por sí mismo, de manera que pueda consultarse de manera independiente de los demás, según las necesidades o los intereses del lector.
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Speks, Amanda. "The import(ance) of conflict minerals : An ideal type analysis of the EU’s regulation on conflict minerals". Thesis, Försvarshögskolan, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:fhs:diva-8355.
Testo completoAbstract (sommario):
The purpose of this study is to determine to what extent the European Union (EU) functions as a market power in the case of conflict mineral regulation. Previous research by Partzsch has shown that the EU response to conflict minerals only somewhat qualifies for the EU to be seen as a normative power. There appears to be a clash between the norms of sustainable development and economic development, which could explain why the EU does not fully qualify as a normative power. Another theoretical framework has thus been chosen to explain the EU’s function in the case of conflict minerals. This theoretical framework is Market Power Europe (MPE) by Damro, which does not look to the collective norms of the EU, but rather on the market-related policies that the Union uses to influence other actors. With the use of an ideal type analysis of EU policy and official documents, this study found that the case fills the criteria to function as a market power in the case of conflict minerals.
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Garrine, Cármen Maria Lucas Pedro. "Efeitos de dois níveis de sulfato de cobre e cobre metionina no metabolismo e oxidação de lipídios em ovinos". Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/74/74131/tde-11022014-091249/.
Testo completoAbstract (sommario):
O cobre está associado ao metabolismo de lipídios, sendo bastante importante na redução do colesterol, e à estabilidade oxidativa da carne, por fazer parte de algumas enzimas antioxidantes. Atributos esses que tornam cada vez mais interessante a pesquisa do uso do mineral em várias espécies, com vista a melhorar a qualidade de vida dos consumidores, uma vez que se pode reduzir o risco de doenças cardiovasculares e câncer, assim como dos fornecedores de carne pelo possível aumento da vida de prateleira e das características organolépticas do produto. Desse modo, o objetivo deste estudo foi determinar o efeito da suplementação com dois níveis de sulfato de cobre e cobre metionina sobre o metabolismo de lipídios e colesterol e estabilidade oxidativa lipídica da carne em cordeiros Merino x Texel. Para o efeito, um experimento foi conduzindo na FZEA, USP de Pirassununga utilizando 40 cordeiros Merino x Texel, que foram distribuídos aleatoriamente em 5 tratamentos, totalizando 8 animais em cada. Os animais foram alojados em gaiolas individualizadas para estudo de metabolismo e o experimento teve a duração de 120 dias. Os tratamentos usados foram: controle, sem adição; suplementação com 10 ou 30 mg de Cu/Kg de MS na forma de sulfato de Cobre; suplementação com 10 ou 30 mg de Cu/Kg de MS na forma de cobre metionina. Foram feitas biópsias do fígado dos animais no tempo zero para análise de cobre e colhidas amostras de sangue para dosagem sérica de Cu. Nos dias 0, 28 e 56 foram colhidas amostras de sague para dosagem de colesterol total, HDL e triglicerídeos. Ao final do experimento, os animais foram abatidos para colheita de amostras de fígado para determinação dos teores de Cu; dosagem das enzimas glutationa reduzida (GSH), glutationa oxidada (GSSH), atividade das enzimas antioxidantes, superóxido dismutase (SOD) e glutationa peroxidase (GP-x) e determinação dos níveis das substâncias reativas ao ácido tiobarbitúrico (TBARS). No momento da desossa foi medida a espessura da gordura subcutânea entre a 12ª e 13ª costela. No mesmo momento, foram colhidas amostras do músculo longissimus para dosagem de colesterol total, análise de perfil de ácidos graxos e TBARS. O músculo longissimus esquerdo foi retirado e congelado a vácuo por 12 meses, após os quais amostras foram colhidas e expostas no expositor refrigerado a 4°C para estudo da estabilidade oxidativa lipídica que foi acompanhada pelos valores de TBARS nos dias 0, 3 e 6. A suplementação com cobre proporcionou maior acúmulo de Cu no fígado (P<0,05), porém, a concentração do elemento no músculo não foi alterada pela suplementação. Não houve diferença significativa (P>0,05) para espessura de gordura subcutânea, concentrações séricas de triglicerídeos, colesterol total, HDL e LDL entre os tratamentos controle e suplementação com cobre, independentemente da fonte. A suplementação com cobre alterou o perfil de ácidos graxos da carne (P<0,05), com aumento na proporção do ácido láurico (C12:0) do grupo controle comparado com os demais tratamentos (P<0,05). Houve redução da concentração de colesterol no músculo longissimus (P<0,05) dos cordeiros suplementados com Cu em relação ao grupo controle, acompanhado de redução (P<0,05) da concentração da GSH e aumento da GSSG no fígado (P<0,05). Não houve efeito da suplementação para níveis de TBARS no fígado (P>0,05), mas houve efeito significativo (P<0,10) no longissimus colhido no momento da desossa. A suplementação com Cu não teve efeito sobre os valores de TBARS para as amostras dispostas na vida de prateleira, porém, houve aumento linear desses valores ao longo do tempo. A suplementação com Cu aumentou a atividade da SOD e GP-x (P<0,05) no fígado. Estes resultados sugerem que o cobre pode ser usado para melhorar a qualidade de carne sem afetar a sua estabilidade oxidativa lipídica.Copper is associated with lipid metabolism, becoming very important in reducing cholesterol and oxidative stability of meat, because it is part of some antioxidant enzymes. These attributes make interesting the research of this mineral in various animal species to improve the quality life of consumers, since they can reduce the risk of cardiovascular diseases and cancers, as well as of the suppliers of the meat due to the possibility of increase the shelf life and organoleptic characteristics. So the aim of this study was to determine the effect of two levels of copper sulphate and copper methionine on lipid and cholesterol metabolism and lipid oxidative stability in meat of Merino x Texel lambs. For that, an experiment was conducted in the Faculty of Animal Science and Food Engineering, University of São Paulo, at the Pirassununga Campus using forty male lambs, Merino x Texel, randomly distributed into 5 treatments groups of 8 animals each. The animals were housed in individualized cages for the study of sheep metabolism, for a period of 120 days. Treatments used were: control, without addition of Cu (Co); 10 or 30 mg of Cu/kg of DM in the form of Cu sulphate (CuSO4); 10 or 30 mg of Cu/kg of DM in the form of copper methionine (Cu-methionine). Liver biopsies were carried out in all animals to determine initial hepatic Cu level. On day 0, 28 and 56 of the experiment blood were collected for analysis of total cholesterol, HDL cholesterol (HDL) and triglycerides. At the end of the experiment, animals were humanely slaughtered and liver samples were collected for later for analysis of Cu, reduced glutathione (GSH), oxidized glutathione (GSSG), glutathione peroxidase (GP-x), superoxide dismutase (SOD) and thiobarbituric acid reactive substances (TBARS). After 24 hours of cooling, left carcasses halves were sawed into two parts between the 12th and the 13th rib to obtain the fat thickness (EGSC). During sawing muscle sample from m. longissimus were collected for determination of cholesterol, fatty acids profiles and TBARS. At the same time, m. longissimus muscle entire was collected and frozen under vacuum for 12 months for study of oxidative stability. After that, steaks of m. longissimus were collected and exposed to \"display life\" (DL) (4°C) to study oxidative stability which was accompanied by TBARS values on days 0, 3 and 6. The copper supplementation resulted in higher concentration and accumulation of Cu in the liver (P<0.05), however, the concentration of Cu in muscle was not altered by supplementation (P>0.05). There was no significant effect (P>0.05) for fat thickness, serum triglycerides, total cholesterol, HDL and LDL between control and copper supplementation regardless of the source. The copper supplementation altered the fatty acid profile of the meat (P<0.05), with an increase in the proportion of lauric acid (C12: 0) in the control group compared with the other treatments (P<0.05). Copper supplementation reduced cholesterol concentration in m. longissimus (P<0.05) in supplemented lambs compared to the control group, this reduction was accompanied by reduction concentrations of GSH (P<0.05) and increasing of oxidized glutathione (GSSG) in the liver (P<0.05). There was no effect of Cu supplementation for TBARS in the liver however, there was significant effect on m. longissimus collected during sawing (P<0.10). There was no effect of Cu supplementation for TBARS in the m. longissimus exposed in the \"Display Life after 12 months vacuum freezing (P>0.05), but there was a linear increase in TBARS values during this period. Cu supplementation increased the activity of SOD and GP-x (P<0.05) in the liver. These results suggest that copper can be used to improve meat quality without affecting the oxidative stability.
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Correa, Lisia Bertonha. "Efeitos de diferentes fontes e níveis de cobre no desempenho, \"status\" de Cu, fermentação ruminal, metabolismo e oxidação de lipídios em bovinos". Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/74/74131/tde-29092010-142724/.
Testo completoAbstract (sommario):
O cobre está associado ao metabolismo de lipídios, sendo bastante importante na redução do colesterol, e à estabilidade oxidativa da carne, por fazer parte de algumas enzimas antioxidantes. Porém, quando na forma iônica, é considerado um elemento pró-oxidante. O cobre orgânico não apresenta esse efeito e, além disso, geralmente apresenta maior biodisponibilidade que fontes inorgânicas. Desse modo, o objetivo deste estudo foi determinar o efeito da suplementação com dois níveis e duas fontes de cobre (inorgânica e orgânica) sobre o desempenho, concentração de cobre no fígado, músculo e sangue, fermentação ruminal, parâmetros oxidativos e metabolismo de lipídios e colesterol. Trinta e cinco bovinos da raça Nelore em fase de terminação foram divididos em 5 grupos, com 7 animais por tratamento, conforme descrição: 1) C: Dieta controle, sem a suplementação adicional de cobre; 2) I10: suplementação de 10mg de Cu/kg de MS na forma de sulfato de cobre; 3) I40: suplementação de 40mg de Cu/kg de MS na forma de sulfato de cobre; 4) O10: suplementação de 10mg de Cu/kg de MS na forma de proteinato de cobre; 5) O40: suplementação de 40mg de Cu/kg de MS na forma de proteinato de cobre. A suplementação com cobre proporcionou maior concentração e acúmulo de Cu no fígado (p<0,05), sendo a maior média observada para o tratamento O40, porém, o status de Cu no músculo e no soro não foram alterados pelos tratamentos. A maior atividade da ceruloplasmina (p<0,05) foi observada para o tratamento I40. Não houve efeito significativo (p>0,05) para ganho de peso diário, ingestão de matéria seca, eficiência alimentar, rendimento de carcaça quente e fria, perda pelo frio, espessura de gordura subcutânea e área de olho de lombo dos bovinos, entre os tratamentos controle e suplementação com cobre inorgânico ou orgânico. O pH ruminal, os ácidos graxos voláteis e o nitrogênio amoniacal também não foram influenciados (p>0,05) pelos tratamentos. Em geral, a suplementação com cobre alterou o perfil de ácidos graxos da carne (p<0,05), com aumento na proporção de ácidos graxos insaturados em detrimento dos ácidos graxos saturados. Não houve efeito de tratamento para TBARS (substâncias reativas ao ácido tiobarbitúrico) no fígado e na carne embalada a vácuo (p>0,05), porém houve redução nos valores de TBARS na carne dos bovinos suplementados com Cu para as amostras dispostas no Display Life (tratamentos I40 e O40, p=0,06), e na atmosfera modificada (tratamentos I10, I40, O10 ou O40, p<0,05), em relação ao tratamento controle. A suplementação com Cu (tratamentos I40 e O40) aumentou a atividade da SOD (superóxido dismutase) (p<0,05), em relação ao tratamento controle, mas não influenciou a atividade da GSH-Px (glutationa peroxidase) (p>0,05). Não houve efeito da suplementação sobre triglicérides e colesterol no sangue; entretanto, em geral, houve redução da concentração de colesterol no músculo L. dorsi (p<0,05), em relação ao tratamento controle, através da redução (p<0,05) da concentração de GSH e da relação GSH/GSSG.Copper is associated with lipid metabolism, becoming very important in reducing cholesterol, and with oxidative stability of meat, because it is part of some antioxidant enzymes. However, when in the ionic form, is considered a pro-oxidant element. The organic copper did not exhibit this effect and, besides, presents higher bioavailability than inorganic sources. Thus, the aim of this study was to determine the supplementation effect of two levels and two sources of copper (inorganic and organic) on the performance, Cu concentration in liver, muscle and blood, ruminal fermentation, oxidative parameters and metabolism of lipids and cholesterol. Thirty-five Nellore cattle in the finishing phase were divided into 5 groups with 7 animals per treatment, as described: 1) C: control diet, without additional Cu supplementation; 2) I10: 10mg Cu/kg DM, as Cu sulfate; 3) I40: 40mg Cu/kg DM, as Cu sulfate; 4) O10: 10mg Cu/kg DM, as Cu proteinate; 5) O40: 40mg Cu/kg DM, as Cu proteinate. Supplementation with copper provided higher Cu concentration and accumulation in the liver (p<0.05), with the highest mean observed for the O40 treatment, nevertheless the Cu status in muscle and serum were not affected by treatments. The highest activity of ceruloplasmin (p<0.05) was observed for the I40 treatment. There was no significant effect (p>0.05) for daily weight gain, dry matter intake, feed efficiency, hot and cold carcass yield, cold loss, backfat and loin eye area of cattle, among control treatment and supplementation with inorganic or organic copper. Ruminal pH, volatile fatty acids and ammonia were not influenced (p>0.05) by treatments. In general, copper supplementation altered the meat fatty acid profile (p<0.05), with an increase in the proportion of unsaturated fatty acids over saturated fatty acids. There was no treatment effect for TBARS (thiobarbituric acid reactive substances) in liver and meat vacuum packed (p>0.05), but there was a reduction in TBARS values in meat from cattle supplemented with Cu for samples prepared on Display Life (treatment I40 and O40, p=0.06), and modified atmosphere (treatment I10, I40, O10 and O40, p <0.05), compared to the control treatment. Supplementation with Cu (treatment I40 and O40) increased the activity of SOD (superoxide dismutase) (p<0.05) compared to control treatment, but did not influence the activity of GSH-Px (glutathione peroxidase) (p>0.05). There was no effect of supplementation on triglycerides and cholesterol in blood, however, there was a reduction in cholesterol concentration in L. dorsi muscle (p<0.05) compared to the control treatment, by reducing (p<0.05) of GSH concentrations and the GSH/GSSG ratio.
49
Kaminskienė, Jurga. "Mineralinių medžiagų panaudojimas dėsliųjų vištų ir viščiukų broilerių mityboje". Master's thesis, Lithuanian Academic Libraries Network (LABT), 2008. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2008~D_20080317_134022-62942.
Testo completoAbstract (sommario):
Per pastaruosius 20 metų daug pasiekta auginant viščiukus broilerius – ženkliai padidėjo viščiukų augimo greitis ir maisto pasisavinimo efektyvumas. Šiuolaikiniai komerciniai hibridai greitai vystosi ir jiems reikia daug energijos turinčių lesalų, kurie leidžia maksimaliai išnaudoti jų genetines galimybes. Daugiau pasiekta ir vištų dedeklių lesinime balansuojant lesalus skirtingais dėslumo etapais, ypač ankstyvojo dėjimo periodu. Pastaruoju metu paukščių lesinime didelis dėmesys skiriamas optimaliam kalcio, fosforo, natrio, kalio ir chloro subalansavimui. Parinkus netinkamas kalcį ir fosforą nešančias medžiagas, taip pat nesubalansavus natrio, kalio ir chloro tarpusavio santykio, t.y. anijonų katijonų balanso, padidėja vandens suvartojimas, sutrinka virškinimo trakto mikrobiologinė pusiausvyra, blogėja kraiko kokybė ir mikroklimato parametrai, susidaro sąlygos paukščiams susirgti ascitais, padaugėja paukščių staigių gaišimo atvejų. Vitaminai ir mineralai yra svarbi sudedamoji paukščių raciono dalis. Šios medžiagos įtraukiamos į racioną kaip priedai atitinkamais kiekiais, kad būtų patenkintas jų poreikis sveikiems produkciją duodantiems paukščiams. Mineralų ir vitaminų trūkumas gali būti kritiškas tam tikrais organizmo vystymosi etapais, todėl kai kurie autoriai teigia, kad net ir trumpas vitaminų bei mineralų apribojimas augimo fazės metu gali turėti neigiamų pasekmių.
Magistrinio darbo tikslas – nustatyti mineralinių medžiagų įtaką dėsliųjų vištų ir viščiukų broilerių... [toliau žr. visą tekstą]Minerals play a very important role in digestion and metabolism of poultry. They are necessary, for the maintenance, growth, production and health of birds. Laying hens also require minerals, primarily calcium, for eggshell formation. Minerals is divided into the macrominerals (those needed in relatively large amounts) and the micro- or trace minerals. Although microminerals are required only in small amounts, the lack of an adequate dietary supply can be just as detrimental to poultry as a lack of one of the macrominerals. Grains are low in minerals, so all poultry feeds contain supplemental sources. Calcium, phosphorus and salt are needed in the greatest amounts. Microminerals such as iron, copper, zinc, manganese and iodine are normally supplied through a trace mineral mix. The minerals influence by the bird‘s physiological status, requirement of minerals and its source is describe in the theory part. Two experiment were performed with broiler chickens and laying hens. The feed intake, feed conversion ratio, birds mortality, the degree of mineralization in the bone tibia, pH, macroelements Ca, P, Mg, Na, K, Cl and alkaline phosphatase in the blood serm were researched in experiment of broiler chickens. Number and weight of eggs, body weight, laying intensity, leftover and utilization of feed to get 1 kg eggs mass, quality parameters of eggshells, the physiological conditions and mortality reasons were researched in test of laying hens. Conclusions. Sodium bicarbonate was... [to full text]
50
Nascimento, Carolina Seno. "Biofortificação agronômica da rúcula com selênio em sistema hidropônico". Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/153604.
Testo completoAbstract (sommario):
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Made available in DSpace on 2018-04-19T11:38:02Z (GMT). No. of bitstreams: 1 nascimento_cs_me_jabo.pdf: 928031 bytes, checksum: 6fefd80272ed55e13cf22f4f5276310c (MD5) Previous issue date: 2018-02-20
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O selênio (Se) é um micronutriente essencial aos seres humanos e animais, entretanto verifica-se frequentemente alimentos pobres neste micronutriente, fato este, explicado principalmente pelo seu baixo teor nos solos. Uma dieta deficiente neste mineral resulta na maior suscetibilidade a uma série de doenças, dentre elas câncer, hipertireoidismo e doenças cardíacas. Nesse contexto, a biofortificação de alimentos é uma alternativa promissora para a inserção do Se na alimentação humana. Assim, objetivou-se avaliar o efeito de doses de Se no crescimento, produção e biofortificação da rúcula. Plantas de rúcula foram cultivadas em ambiente protegido no sistema hidropônico. Foram avaliadas sete concentrações de Se (0, 10, 20, 30, 40, 50 e 60 µmol L-1), utilizando-se o selenato de sódio como fonte de Se. O número de folhas, área foliar, altura, massa fresca e seca da parte aérea, massa seca da raiz e produtividade foram influenciados pelas concentrações de Se. Os melhores resultados foram obtidos entre as concentrações 20 a 29 µmol L-1 de Se. Os teores de enxofre (S) e potássio (K) aumentaram linearmente com incremento no fornecimento de Se. Constatou-se a biofortificação agronômica da rúcula, pois o aumento da concentração de Se na solução nutritiva resultou em aumento no teor deste elemento na planta. Os tratamentos com o fornecimento de Se na solução nutritiva proporcionaram rúculas com teores que variaram de 598,96 a 1437,56 µg kg-1 de Se, em relação às plantas cultivadas em solução nutritiva sem Se que apresentaram 167,84 µg kg-1 de Se.
Selenium (Se) is an essential micronutrient for humans and animals. However, food often presents low content of this micronutrient, which is resulted mainly due to the low content of Se in the soil. The insufficient consumption of this mineral can increase the susceptibility to several diseases, including cancer, hyperthyroidism and heart disease. In this context, the biofortification of food is a promising alternative for Se insertion into the human diet. The objective of this study was to evaluate the effect of Se doses on the growth, production, and biofortification of rocket plants. Rocket plants were grown in a protected environment in the hydroponic system. Seven concentrations of Se (0,10, 20, 30, 40, 50 and 60 μmol L-1) were evaluated. Sodium selenate was used as a source of Se. The number of leaves, leaf area, height, fresh and dry shoot mass, root dry mass and productivity were influenced by the concentrations of Se. The best results were obtained between the concentrations 20 to 29 μmol L-1 of Se. With the supply of Se was possibly observed a linear increase in the sulfur (S) and potassium (K) contents. Agronomic biofortification of rocket plants was verified since the increase of the Se concentration in the nutritive solution resulted in an increase in the content of this element in the plant. Treatments with the supply of Se in the nutrient solution provided rocket plants ranging from 598.96 to 1437.56 μg kg-1 of Se, in relation to plants grown in nutrient solution without Se that presented 167,84 μg kg-1 Se.