Three-dimensional porous single crystals (PSCs) are a recent development in the growing world of mesoporous material. The mesoporosity allows for the material to retain their nanoproperties whilst being bulk in size. The current work concentrates on chromium oxide and cobalt oxide PSCs formed in the templates SBA-15 and KIT-6. HRTEM is the main technique used in this investigation, looking at the morphology and single crystallinity of these materials. A growth mechanism for the PSC material is proposed based on HRTEM observations. XRD studies revealed that the confinement effect, caused by the mesopores, reduces the temperature for both cobalt and chromium oxide crystallisation, as well as a different intermediate route from the metal nitrates. The properties of chromium oxide PSC are also investigated magnetically and catalytically. Some metal oxides in different templates are also presented, despite no PSC forming. HRTEM work on other nanomaterials, based on collaboration, is also presented.

Submitted by Angela Maria de Oliveira (amolivei@uepg.br) on 2018-12-20T16:06:34Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Marcel Adriano Jobbins.pdf: 799698 bytes, checksum: 9bb4362171f6c452c9c0332d5169dd9e (MD5) / Made available in DSpace on 2018-12-20T16:06:34Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Marcel Adriano Jobbins.pdf: 799698 bytes, checksum: 9bb4362171f6c452c9c0332d5169dd9e (MD5) Previous issue date: 2018-09-28 / Este estudo foi desenvolvido para determinar os coeficientes de digestibilidade aparente (CDA) de matéria seca (MS), energia bruta (EB), proteína bruta (PB), amido, lipídios, fibra bruta (FB), cinzas (CZ) e de aminoácidos (AA) essenciais e não essenciais de farinha de feijão in natura (FI) e feijão extrusada (FE) para juvenis de tilápia do Nilo utilizando dois marcadores de digestibilidade: óxido crômio (Cr2O3) ou cinza insolúvel em ácido (CIA). Foi elaborada uma dieta referência peletizada (DR) contendo 35,19% de PB e 17,78 MJ/ kg de EB. As dietas testes constituíam-se de 70% da DR e 30% de FI ou FE. Grupos de 15 individuos (150,16 ± 20,32 g) foram distribuídos em seis aquários de digestibilidade de 200 L, em um esquema fatorial 2 x 2, onde foram avaliados dois métodos de processamento (FI ou FE) e dois marcadores (Cr2O3 ou CIA), com duas repetições, compondo o “pool” de fezes de cada dieta testada. Os maiores CDA, referentes a interação (processamento x marcador), foram encontrados para MS, EB, PB, CZ e AA essenciais como: arginina (Arg), histidina (His), isoleucina (Ile), leucina (Leu), lisina (Lys), metionina (Met),fenilalanina (Phe), treonina (Thr) e nos AA não essenciais: ácido aspártico (Asp), cisteína (Cys), ácido glutâmico (Glu), glicina (Gly), serina (Ser) e tirosina (Tyr). O CDA de amido e para os AA essencias triptofano (Trp) e valina (Val) foi maior no FE em comparação ao FI, deferenciando dos lipídios que apresentaram melhores resultados para FI. Para FB e o AA não essencial alanina (Ala), por sua vez, não houve influência dos tratamentos dietéticos e marcadores. Independentemente do processamento a Met, His e Arg foram os AA limitantes para dietas contendo farinhas de feijão. Em conclusão, a FE apresentou -se como sendo boa fonte de energia e nutrientes, porém, os teores de Met e Cys devem ser considerados para as necessidades dietéticas de AA contendo enxofre e o marcador CIA não se mostrou sendo confiável para tilápia do Nilo. / The trial aimed to evaluate the apparent strain digestibility coefficients (ADC) of dry matter (DM), gross energy (GE), crude protein (CP), starch, lipids, crude fiber (CF), ashes (AS) and essential and non-essential amino acids (AA) of in natura bean flour (FI) and extruded bean flour (FE) for juvenile Nile tilapia using two digestibility markers: chromium oxide (Cr2O3) or acid insoluble ash (AIA). It was elaborated a pelleted reference diet (RD) containing 35.19% CP and 17.78 MJ / kg GE, the test diets consisted of 70% RD and 30% of FI or FE. Groups of 15 individuals (150.16 ± 20.32 g) were distributed in six digestibility aquariums of 200 L, in a 2 x 2 factorial scheme, two processing methods (FI or FE) and two markers (Cr2O3 or AIA) were evaluated, with two replicates, composing the faeces pool of each diet tested. The highest ADC referring to the interaction (processing x marker) were found for DM, GE, CP, As and essential AA as: arginine (Arg), histidine (His), isoleucine (Ile), leucine (Leu), lysine (Lys), methionine (Met), phenylalanine (Phe), threonine (Thr) and for non-essential AAs: aspartic acid (Asp), cysteine (Cys), glutamic acid (Glu), glycine (Gly), serine (Ser) and tyrosine (Tyr). The CDA of the starch and the essential AA tryptophan (Trp) and valine (Val) was higher in FE compared to FI, different from lipids, which presented better results for FI. For GE and nonessential amino acid alanine (Ala) there was no influence of dietary treatments and markers. Regardless of the processing, Met, His and Arg were the limiting AAs for diets containing bean flours. In conclusion, FE proved to be a good source of energy and nutrients, however, the low levels of Met and Cys should be considered for the dietary requirements of AA containing sulfur. The AIA marker proved to be unreliable for Nile tilapia.

Chromium is an important alloying element in stainless steel but also environmentally harmful element. A number of mineralogical phases present in the slag matrix can contain chromium and lead to chromium leaching. Chromium in slag if not stabilized, could oxidize to the cancerogenic hexavalent state, and leach out if exposed to acidic and oxygen rich environment. Other environmental concerns are slag dusting and chromium escape to the atmosphere. Despite the fact that there is a certain risk of Cr-emission from slags at operating conditions, still very little is known regarding the emission of the oxides of chromium during the slag tapping. Spinel phase is known to be important for controlling the leaching properties of chromium from the slag. The objective of the present study was to get an understanding of the phase relationships and chromium partition in the chromium-containing industrial slags and synthetic slags with a view to control the chromium stabilization in spinel phase. The impact of slag basicity, heat treatment, oxygen partial pressure and Al2O3 addition, on the phase relationships and chromium partition has been determined. The experimental results were compared with the phase equilibrium calculations. It was found that the oxygen partial pressure in the gas phase had a strong impact on chromium partition. The experimental results show that the impact of the slag basicity on chromium partition at lower oxygen partial pressures was negligible in contrast to that in air. The amount of spinel phase was found to increase with increased Al2O3 content. Slow cooling of slag and soaking at low oxygen partial pressure would improve the spinel phase precipitation. This treatment will also lead to less Cr dissolved in the unstable matrix phases. Chromium oxide was found to be emitted when chromium containing slags were exposed to oxidizing atmosphere. The results indicate that chromium oxide evaporation increases with increase in temperature and oxygen partial pressure, but decreases with slag basicity and sample thickness. / <p>QC 20131114</p> / Steel Eco-Cycle

Fundação de Amparo a Pesquisa no Estado do Rio Grande do Sul / The work was developed with the objective to evaluate the intake of forage and beef heifers performance from 15 to 18 months old, grazing in Alexandergrass (Urochloa plantaginea (Link) Hitch) under rotational grazing method, receiving rice bran (FAI) as a supplement, at different levels (0, 0.5 and 1.0% of body weight (BW)). The experimental design was completely randomized with repeated measures over time. The use of FAI increased the total intake of dry matter (DM), total intake of crude protein and total digestible nutrients in relation to heifers exclusively on pasture. The heifers that received 1.0% PC FAI reduced the intake of forage DM increasing by 18% stocking rate (SR) and 27% BW gain per hectare (BWA) compared with the system exclusively in pasture. In the system in which the heifers received FAI at 0.5% of BW the SR and BWA were similar to other systems. In this feed system daily weight gain 18% higher than heifers exclusively on pasture and similar gain to the use of FAI at 1.0% of BW were observed. In Alexandergrass pasture under rotational grazing, using FAI at 0.5% of BW for beef heifers from 15 to 18 months of age is recommended to promote higher production response when compared to heifers exclusively on pasture and similar production when provided FAI at 1.0% of BW. / O trabalho foi desenvolvido com o objetivo de avaliar o consumo de forragem e o desempenho de novilhas de corte dos 15 aos 18 meses de idade, em pastejo em papuã (Urochloa plantaginea (Link) Hitch), sob método rotativo de pastejo, recebendo farelo de arroz integral (FAI) como suplemento, em diferentes níveis (0, 0,5 e 1,0% do peso corporal (PC)). O delineamento experimental foi o inteiramente casualizado, com medidas repetidas no tempo. O uso de FAI aumentou o consumo total de matéria seca (MS), consumo total de proteína bruta e de nutrientes digestíveis totais em relação às novilhas exclusivamente em pastejo. O consumo total de fibra em detergente neutro foi similar nos diferentes sistemas alimentares. As novilhas que receberam 1,0% do PC de FAI reduziram o consumo de MS da forragem, aumentando em 18% a taxa de lotação (TxLot) e em 27% o ganho de PC por hectare (GPA) em comparação com o sistema exclusivamente a pasto. No sistema em que as novilhas receberam 0,5% do PC de FAI a TxLot e o GPA foram similares aos demais sistemas. Nesse sistema alimentar foi observado GDM 18% superior em relação as novilhas exclusivamente em pastejo e ganho similar ao uso de 1,0% do PC de FAI. Em pastagem de papuã, sob pastejo rotacionado, é recomendado o uso de 0,5% do PC de FAI para novilhas de corte dos 15 aos 18 meses de idade, por promover respostas produtivas superiores em relação as novilhas exclusivamente em pastejo e semelhantes as observadas quando fornecido 1,0% do PC de FAI.

Notre étude porte sur des matériaux à effets relativistes importants. L'hamiltonien semi-relativiste, couplé aux équations de Maxwell (EM), permet de déduire les sources de courant et de densité, incluant des termes de second ordre (polarisations de spin et de Darwin). Différents modèles sont développés par expansion des EM. L'étude ab initio montre que (1) le désordre atomique peut produire le ferrimagnétisme (FM) dans GaFeO3 (GFO) multiferroïque, (2) les états 3d Fe des octaèdres déformés ont une levée de dégénérescence tétraédrique (théorie du champ cristallin), (3) la polarisation électrique concorde avec l'expérience, (4) le mécanisme magnétoélectrique (ME) direct est insuffisant pour expliquer le ME observé. Pour Cr2O3, le calcul de l'état massif sous contraintes biaxiales n'explique pas son FM, la taille de l'échantillon ou l'excès d'oxygène pourrait de fait être important. Enfin, nous avons développé le XAS et le XMCD dans le code VASP et calculé ces spectres pour GFO. / We studied the physics of materials where relativistic effects are important. We first coupled the semi-relativistic Hamiltonian with the Maxwell's equations, and derived the current and density sources, which included second-order terms like the spin and Darwin polarizations. Different models were developed, by expanding the Maxwell's equations. We then performed ab initio studies to explain (1) site disorders as the origin of ferrimagnetism in multiferroic GaFeO3 (GFO), (2) crystal-field theory where the Fe 3d states at the deformed octahedra have tetrahedral splittings, (3) the electric polarization as a function of temperature, and (4) the insufficiency of the direct magnetoelectric (ME) mechanism to explain observed ME behavior. For Cr2O3, bulk calculations for different biaxial strains failed to explain its ferromagnetism, indicating that size or excess-O effects might be important. Finally, we implemented XAS and XMCD in VASP and computed these spectra for GFO.