Fachadas de alumínio na construção moderna

This dissertation aims to elaborate in aluminium façade systems and the materials included and presents the activities in curricular internship held over six months at Martifer Alumínios, S.A. This dissertation focuses on the commonly used materials in aluminium façade systems and presents the main properties that defines the functionalities of façades and provides the whole building with qualities like insulation and weatherproofing. The curricular internship was held at the pre-construction team of Martifer, it included participation and development in the realization of approval drawings and manufacturing plans of London Dock building C1 façade construction project. The last chapter in this dissertation elaborates more specifically in fire resistance of an Aluminium mullion. Based on Eurocodes (EN 1990, EN 1991-1-2, EN 1999-1-1, EN 1999-1-2), the fire resistance verifications were concluded for the studied aluminium mullion with and without fire protection consideredEsta dissertação tem como objetivo elaborar sistemas de fachada em alumínio e os materiais incluídos. Em complemento são apresentadas as atividades do estágio curricular realizadas durante seis meses na Martifer Alumínios, S.A. A dissertação elabora os materiais frequentemente utilizados em sistemas de fachadas em alumínio e apresenta ainda as principais propriedades que definem as funcionalidades das fachadas que visam fornecer qualidades ao edifício como isolamento e impermeabilização. O estágio curricular foi realizado na equipa de pré-construção da Martifer, incluindo a participação e desenvolvimento na realização de desenhos de aprovação e planos de fabrico no projeto que envolve a preparação de fachada do London Dock edifício C1. O último capítulo desta dissertação elabora mais especificamente a resistência ao fogo de um montante de alumínio. Com base nos Eurocódigos (EN 1990, EN 1991-1-2, EN 1999-1-1, EN 1999-1-2), foram concluídas as verificações de resistência ao fogo para um montante de alumínio com e sem proteção contra incêndioMestrado em Engenharia Civi

Comparative study of bioethanol production from sugarcane molasses by using Zymomonas mobilis and Saccharomyces cerevisiae

The study was designed to compare the bioethanol production from Zymomonas mobilis and Saccharomyces cerevisiae using molasses as production medium. The focus was on the retention time at lab scale. Bioethanol and petroleum blend can be used in existing gasoline engines. Present study showed a more cost-effective procedure for production of ethanol from sugar-cane molasses by using bacterial strain "Z. mobilis". Laboratory scale unit was designed to perform the experiments through batch fermentation and to determine the impact of leading parameters, including fermentation temperature, pH, sugar concentration, and nutrients. S. cerevisiae produced 8.3% (v/v) bioethanol provided sugar concentration 14 g /100 ml with the fermentation efficiency of 92.5%. On the contrary, Z.mobilis produced 9.3% (v/v) bioethanol by utilizing 16 g/100 ml sugar with the fermentation efficiency of 90.5%. Effect of nutrients on fermentation was determined using molasses as feedstock. Thin layer chromatography was also performed to assess the possible impurities in molasses as compared to the pure sugar. The pH and fermentation temperature was optimized for the enhanced yield of bioethanol.Key words: Bioethanol, molasses, fermentation, Zymomonas mobilis, Saccharomyces cerevisiae

Amphiphilic diblock copolymer based multi-agent photonic sensing scheme

Efficient functionalization of polymer optical fibers’ (POF) surface by a novel block copolymer material towards the development of low cost multi-agent sensors is presented. The employed poly(styrene sulfonate-b-tert-butylstyrene) diblock copolymer (SPS-b-PtBS) possesses two blocks of distinctively different polarity and charge, the hydrophilic SPS which is sensitive to polar substances and the hydrophobic PtBS which is sensitive to organic solvents. The coexistence of two different blocks allows for the detection of a wide variety of agents, ranging from ammonia, and organic solvents, to biomolecules like lysozyme, at room temperature as opposed to alternative usually more complicated techniques, all with the sole use of one sensing medium. Copolymers' high glass transition temperature enables the formation of stable and environmentally robust overlayers. The sensing performance of the material is evaluated experimentally on the customizable platform of polymer optical fibers, demonstrating fast response, high operational reversibility and also reusability in successively different testing agents

The design and thermo-structural analysis of target assembly for high intensity neutron source

The engineering design of an integrated target assembly of IFMIF lithium target was performed in IFMIF/EVEDA project for a high intensity neutron source. In the evaluation of the design, a thermos-structural analysis of was evaluated by ABAQUS code, and the modeling region was a part of the target assembly which was from the inlet nozzle to the outlet pipe. The material of the target assembly including the back plate was F82H steel. In the thermal-structural analysis, the normal operations and start/stop or abnormal operations were evaluated at 250 or 300 °C operation of Li flow in inlet pipe. The result showed that the temperature of the target assembly was evaluated to be still lower than the Li boiling point of 344 °C under a vacuum pressure of 10−3 Pa. In a temperature constant operation, the calculated stresses and displacements were small enough for thermal soundness of the target assembly in steady states. In a transient cooling process from 300 °C to 20 °C through 250 °C, the maximum Mises stress was found to be 372 MPa, which was lower than the yield stress at 300 °C. Keywords: High intensity neutron source, Target assembly, Thermo-structural analysis, Li target, IFMIF, F82

Advancements Towards Single Site Information Storage and Processing Using HfO2 Resistive Random Access Memory (ReRAM)

Resistive Random Access Memory (ReRAM) has attracted much attention among researchers due to its fast switching speeds, lower switching voltages, and feasible integration into industry compatible CMOS processing. These characteristics make ReRAM a viable candidate for next-generation Non- Volatile Memory. Transition-Metal-Oxides have been proven to be excellent materials for ReRAM applications. This work investigates the effect of various, post-deposition anneals (PDA) on the switching parameters of Ni/Cu/HfO2/TiN Resistive Memory Devices (RMD). Results are presented in the form of a Small Business Innovation Research (SBIR) grant proposal. The use of the SBIR format emphasizes understanding of the experimental design, commercial viability, and broader impacts of ReRAM technology

Synthesis of hydroxyapatite (HAp) and microwave assisted TiO2-HAp composite coating on Commercially pure (CP)-Titanium for biomedical applications

Hydroxyapatite (HAp) is an important bioceramic material widely used for many biomedical applications owing to its similarity to the inorganic composition of bone. Hydroxyapatite was synthesized by using wet precipitation method using calcium nitrate and diammonium hydrogen phosphate as a precursor. To maintain a constant pH, ammonium hydroxide solution was used. After synthesis, HAp samples were calcined at 850 °C and 1200 °C, for 2 hours, and allowed to cool at room temperature. The synthesized HAp and calcined HAp samples were characterized by X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscope (SEM), and transmission electron microscopy (TEM). Zeta potential test was performed and its values were found to be between -14.7 mV and -15.7 mV. The result inferred that hydroxyapatite particles would get precipitated in a short span of time and, not stable in colloidal solution. Dynamic light scattering (DLS) was also used to determine particle size distribution. The z-average diameter of particles was found to range from 400 nm to 457 nm. Transmission electron microscopy (TEM) result confirmed that calcined HAp (1200°C) has the largest particle size and synthesized HAp has the smallest particle size. After synthesis of HAp, microwave (MW) has been used as a substitutive method for HAp-based composite coatings on commercially pure (CP) titanium substrate. This is performed to enhance the bioactivity which is an important property for biomedical implants. The coating was made by microwave processing of CP-Ti packed in HAp at moderately higher microwave power. The composition of coating demonstrates TiO2 as a major phase (which was formed due to oxidation) along with HAp as a minor phase. Synthesized HAp and calcined (850 °C) HAp coating on CP-Ti were performed and characterized. The XRD and SEM results confirmed the presence of TiO2 and HAp on the CP-Ti specimens. The coated samples showed improved mechanical and biological performances. Microhardness of CP-Ti specimens increased after microwave processing, as the microhardness values of uncoated, synthesized HAp coated, and calcined (at 850 °C) HAp coated CP-Ti samples are 172.64 HV, 192.1 HV, and 192.45 HV respectively. Hence the studied showed that TiO2-HAp coated CP-Ti specimens has significant potential in a biomedical application with improved bioactive properties

Aluminum powder metallurgy processing

In recent years, the aluminum powder industry has expanded into non-aerospace applications. However, the alumina and aluminum hydroxide in the surface oxide film on aluminum powder require high cost powder processing routes. A driving force for this research is to broaden the knowledge base about aluminum powder metallurgy to provide ideas for fabricating low cost aluminum powder components. The objective of this dissertation is to explore the hypothesis that there is a strong linkage between gas atomization processing conditions, as-atomized aluminum powder characteristics, and the consolidation methodology required to make components from aluminum powder;The hypothesis was tested with pure aluminum powders produced by commercial air atomization commercial inert gas atomization and gas atomization reaction synthesis (GARS). The commercial atomization methods are bench marks of current aluminum powder technology. The GARS process is a laboratory scale inert gas atomization facility. A benefit of using pure aluminum powders is an unambiguous interpretation of the results without considering the effects of alloy elements;A comparison of the GARS aluminum powders with the commercial aluminum powders showed the former to exhibit superior powder characteristics. The powders were compared in terms of size and shape, bulk chemistry, surface oxide chemistry and structure, and oxide film thickness. Minimum explosive concentration measurements assessed the dependence of explosibility hazard on surface area, oxide film thickness, and gas atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization oxidation of aluminum powder. An Al-Ti-Y GARS alloy exposed in ambient air at different temperatures revealed the effect of reactive alloy elements on post-atomization powder oxidation;The pure aluminum powders were consolidated by two different routes, a conventional consolidation process for fabricating aerospace components with aluminum powder and a proposed alternative. The consolidation procedures were compared by evaluating the consolidated microstructures and the corresponding mechanical properties. A low temperature solid state sintering experiment demonstrated that tap densified GARS aluminum powders can form sintering necks between contacting powder particles, unlike the total resistance to sintering of commercial air atomization aluminum powder

Electrochemical investigations of surfactants influence on copper ions cementation

The paper presents the results of experiments aimed to determine the effect of surfactants on the cementation rate and activation energy. The study was carried out on model solutions with the addition of surfactants. The results of the study showed that sodium lignosulfonate in a mixture with sodium dodecyl sulfate and sodium dodecylbenzene sulfonate increases the cementation rate over the entire range of studied concentrations. It is noted that the addition of individual surfactants leads to an increase in activation energy. Activation energy increases according to following order: sodium dodecylbenzene sulfonate → sodium dodecyl sulfate → sodium lignosulfonate. © Published under licence by IOP Publishing Ltd.Russian Science Foundation, RSF: 18-19-00186Leaching experiments and grade size analysis were conducted at the expense of the Russian Science Foundation grant (project No. 18-19-00186)

Treatment of Arsenic-Bearing Minerals and Fixation of Recovered Arsenic Products: An Updated Review

Mineral processing and extractive metallurgical operations have created and are creating appreciable arsenic bearing wastewater and waste solid products that have to be handled, treated for recycle, or treated for environmentally safe disposal. At present there are intense research and operational activities being conducted to provide the best viable processing procedures to ensure that the mineral processing and extractive metallurgical industries are profitable and environmentally secure. The focus of this presentation is on the element arsenic, even though many other deleterious elements may also be present in ores and concentrates. Numerous base metal resources contain arsenic bearing minerals, especially resources containing mineral sulfides. Information on presently treated metal-bearing resources and potential new resources is voluminous, especially for those containing arsenic mineralization. The influence of elevated arsenic concentrations in the treatment of copper-arsenic sulfides and to a lesser extent the treatment of copper-gold-arsenic sulfides are considered in this presentation. Because of chapter page limitations not all treatment processes are discussed, however, examples are provided to illustrate arsenic problems and industrial solutions. The major emphasis of this presentation has been placed on the present state-of-the-art for arsenic immobilization/fixation and long-term storage considerations