Orientador: Flavio Alessandro Serrão Gonçalves / Resumo: A estimação do tempo de vida útil de um transformador de potência pode viabilizar a melhoria do uso do ativo, bem como do planejamento quanto a sua confiabilidade frente ao seu impacto no sistema elétrico de potência por falhas. Neste contexto este trabalho realiza uma análise das principais metodologias de avaliação para ciclos de vida útil de transformadores de potência. As análises utilizam dados de medição de grandezas elétricas, medições de temperatura, além das quantificações dos elementos químicos e físicos presentes nos isolantes líquidos dos transformadores. O desenvolvimento concentra-se no estudo e reprodução de 2 metodologias, a primeira embasada na avaliação de um indexador de saúde dos transformadores e uma segunda metodologia que utiliza uma análise combinatória de indexador de saúde com posterior tratamento estatístico, para as reproduções das metodologias foram utilizados dados de operação, manutenções preventivas e corretivas referentes ao parque instalado de 290 transformadores em operação, com potências nominais entre 12,5 MVA e 50 MVA e com tensões em seu enrolamento de alta tensão de 69 kV e 138 kV, de uma distribuidora de energia. Posteriormente à reprodução dos modelos de forma massiva, foram avaliadas as suas respostas quanto aos dados e realizadas análises críticas do desempenho das máquinas frente as metodologias utilizadas. / The estimation of the useful life of a power transformer can enable the improvement of the asset’s use, as well as the planning of its reliability in relation to its impact on the power system due to fails. In this context this work performs an analysis of the main evaluation methodologies for power transformer life cycles. The analysis uses electrical measurement data, temperature measurements, as well as quantification of chemical and physical elements present in the liquid insulation of the transformers. The development focuses on the study and reproduction of two methodologies, the first one based on the evaluation of a health index of the transformers a second methodology that uses a combinatorial analysis of health index subsequent reprocessing of the methodologies, operation data, preventive and corrective maintenance were used for 290 installed transformers, with rated power between 12.5 MVA and 50 MVA and with voltages in its high voltage winding of 69 kV and 138 kV from an energy distributor. After the application of the models in a massive way, their answers results were evaluated and critical analysis of the performance of the machines were carried out against the methodologies used. / Mestre

Packaging plays an important role in ensuring food safety and quality. The development antimicrobial packaging enables actively inhibiting/killing the spoilage microorganisms, and thus extending food product's shelf life. Generally, 50% shelf life extension is possible. The interest for using metallic nanoparticles in active packaging derives from its superior antimicrobial efficacy and no negative impact on the food sensory properties. In this thesis, the packaging material of concern is a PLA (Polylactic Acid) coated paper incorporating zinc oxide nanoparticles (ZnO NPs) in the coating layer. The material was characterized and its antimicrobial activity was evaluated. The SEM images show that the nanoparticles were homogenously distributed across the surface thanks to its surface modification. Antimicrobial assay indicates that the active material was effective in inactivating E. coli and S. aureus. Furthermore, E. coli was found to be more susceptible to this type of agent, showing 3.14 log reduction for 0.5 wt% agent loading in the PLA coating layer. This result was compared across the publications using the same agent for treating both Gram-positive and Gram-negative microorganisms. The discrepancy between the results can be explained by the fact that ZnO nanoparticles have multiple action mechanisms, and different antimicrobial testing methods may activate part of the action mechanisms. On the other hand, recyclability is regarded as an important attribute for paper-based packaging material, as it enables to conserve the resources and reduce the environmental impacts. Accordingly, when it comes to the nano-enabled paper packaging material, recyclability should be maintained. In this case, a recyclability test was carried out in a lab-scale paper recycling line. The protocol was based on a method adapted from the ATICELCA MC501-13, which enabled to recover over 99% of the solids material. The mass balance result indicates that 86%-91% zinc oxide nanoparticles ended up in the rejected material stream, mostly embedded within the polymer coating; whereas 7%-16% nanoparticles ended up in the accepted material stream. Besides, the tensile strength of the recycled handsheets suggests that the nano-enabled coating had no negative impacts on the recovered fibre quality. Active packaging plays a positive role in reducing food losses. If food and packaging are considered as a whole system, its overall environmental impact can be justified by incorporating the food loss reduction due to the application of active packaging. The LCA calculation shows that a breakeven point can be easily achieved for the case of red meat products of high environmental impact. / El envase juega un papel importante asegurando la seguridad y calidad de los alimentos. El desarrollo de envases activos, especialmente envase antimicrobiano, permite inhibir o matar los microorganismos causantes del deterioro de los alimentos, alargando por tanto su vida útil. De forma general es posible extender la vida útil de los alimentos en un 50%. El interés por el uso de nanopartículas metálicas en el envasado activo se deriva de su gran efectividad antimicrobiana sin causar un efecto negativo en sus propiedades sensoriales. En la presente tesis, se ha desarrollado un papel recubierto de PLA (ácido poliláctico) con nanopartículas de óxido de zinc (ZnO NPs) incorporadas en la capa de recubrimiento. Se ha caracterizado el material y se ha evaluado su capacidad antimicrobiana. Las imágenes obtenidas mediante SEM muestran que las nanopartículas fueron distribuidas a lo largo de la superficie gracias a su modificación. Los ensayos de efectividad antimicrobiana indicaron una actividad del material frente a E. coli y a S. aureus. Además, E. coli resultó ser más susceptible a este agente activo incorporado al 0.5 % en peso en el recubrimiento de PLA, mostrando una reducción de 3.14 log. Este resultado fue comparado con publicaciones donde se emplearon los mismos agentes activos para frente a microorganismos Gram-positivos y Gram-negativos. Las discrepancias encontradas entre los resultados pueden deberse a que las nanopartículas de ZnO tienen múltiples mecanismos de acción, y los diferentes métodos de ensayo poder estimular parte de estos mecanismos. Por otra parte, el reciclado juega un importante papel en la conservación de los recursos y en la reducción de los impactos medioambientales. Por tanto, cuando se trata de un material de envase de papel con sustancias de tamaño nano, el reciclado debe tratarse adecuadamente. El ensayo de reciclabilidad fue llevado a cabo a escala laboratorio en una línea de reciclado de papel. El protocolo de ensayo se basó en el método adaptado de ATICELCA MC501-13, permitiendo una recuperación del 99% de material sólidos. Los resultados del balance de materia indicaron que el 86%-91% de las nanopartículas de óxido de zinc llegaron al flujo de material de rechazo, principalmente mezclado en el recubrimiento polimérico. Además, los resultados de tracción de las láminas recicladas sugieren que el recubrimiento con partículas nano no tiene un efecto negativo sobre la calidad de la fibra recuperada. El envase activo juega un papel positivo en la reducción de los residuos alimentarios. Como resultado del uso del envase activo, considerando el envase y el alimento como un todo, el impacto ambiental sobre este sistema completo puede ser compensado por la reducción de pérdidas de alimentos. El cálculo LCA muestra que el punto de equilibrio se puede conseguir fácilmente en el caso de productos de carne roja de elevado impacto ambiental. / L'envàs té un paper prou important en la seguretat i la qualitat del aliments. El desenvolupament dels envasos actius, especialment l'envàs antimicrobià, el qual permeteix l'inhibició o mort dels microorganismes que produeixen el deteriorament dels aliments i, per tant, allargant la seua vida útil. De manera general, es possible l'allargament de la vida útil dels aliments en un 50%. L'interès per la utilització de nanopartícules metàl·liques en l'envasat actiu es deriva de la seua gran efectivitat antimicrobiana sense produir un efecte negatiu en les seus propietats sensorials. En aquesta present tesis, s'ha desenvolupat un paper recobert de PLA (àcid polilàctic) amb nanopartícules d'òxid de zinc (ZnO NPs) incorporades a la capa de recobriment. S'ha caracteritzat el material i s'ha avaluat la seua capacitat antimicrobiana. Les imatges obtingudes per mitjà del SEM mostren que les nanopartícules foren distribuïdes en tota la superfície gràcies a la seua modificació. Els assajos d'efectivitat antimicrobiana varen indicar una activitat del material front a E.coli i a S. aureus. A més, E. coli va resultar ser més susceptible a aquest agent actiu incorporat al 0.5 % en pes en el recobriment de PLA, mostrant una reducció de 3.14 log. Aquest resultat va ser comparat amb publicacions on es van emprar els mateixos agents actius front a microorganismes Gram-positiu i Gram-negatiu. Les discrepàncies trobades entre els resultats poden deure's a que les nanopartícules de ZnO tenen diversos mecanismes d'acció, i els diferents mètodes d'assaig poder estimular part d'aquestes mecanismes. Per altra banda, el reciclatge també té un paper important en la conservació dels recursos i en la reducció dels impactes mediambientals. Per tant, quan es tracta d'un material d'envàs de paper amb substàncies de la grandària 'nano', el reciclatge ha de tractar-se adequadament. El assaig de reciclabilitat va ser dut a terme a escala de laboratori en una línia de reciclatge de paper. El protocol de l'assaig es va basar en el mètode adaptat d'ATICELCA MC501-13, permetent una recuperació del 99% del material sòlid. Els resultats del balanç de matèria van indicar que el 86-91% de les nanopartícules d'òxid de zinc varen arribar al fluix material de rebuig, principalment mesclat en el recobriment polimèric. A més, els resultats de tracció de les làmines reciclades suggereixen que el recobriment amb nanopartícules nano no tenen un efecte negatiu sobre la qualitat de la fibra recuperada. L'envàs actiu juga un paper positiu en la reducció dels residus alimentaris. Com a resultat de l'ús de l'envàs actiu, considerant l'envàs i l'aliment com un tot conjunt, l'impacte ambiental sobre aquest sistema complet pot ser compensat per la reducció de pèrdues d'aliments. El càlcul LCA mostra que el punt d'equilibri es pot aconseguir fàcilment en el cas de productes de carn roja d'elevat impacte ambiental. / Zhang, H. (2016). Sustainability assessment of active packaging incorporating nanomaterials [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/75348 / TESIS

京都大学 / 0048 / 新制・論文博士 / 博士(農学) / 乙第13339号 / 論農博第2882号 / 新制||農||1079(附属図書館) / 学位論文||R2||N5246(農学部図書室) / 京都大学大学院農学研究科応用生物科学専攻 / (主査)教授 山下 洋, 教授 朝倉 彰, 准教授 益田 玲爾 / 学位規則第4条第2項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Successful service coordination for the homeless depends on the ability of diverse organizations to effectively collaborate. This study utilizes a life-cycle framework to expand on the collaborative governance theory by highlighting the different stages of collaboration that homeless service networks encounter. Activation, collectivity, and institutionalization are three stages used to uncover the unique nature of emergency discharge planning processes. Since collaboration is not a static process and government regulation for emergency discharge plans were recently enacted in 2012, collaborative networks encounter challenges and success factors at different stages. A qualitative case-study approach of organizational leaders in homeless service networks in Texas (Dallas, Ft. Worth and Houston) examines stages of collaboration. Results show common success and challenge factors identified among the three networks, but the factors take on different forms in relation to where the networks are at in the coordination stages. Practitioners can use the findings from this study as a guide to set up benchmarks and measurable objectives to identify strengths and weaknesses in their coordination processes.

Multiple drive belt conveyors are being increasingly incorporated in mining plans worldwide because of their high economic performance and the ease of moving these installations around, especially in underground mines. A typical modern multi-drive conveyor system consists of one or more intermediate drive stations positioned along the upper stretch of the conveyor and a single drive station situated in the lower stretch. Despite the acknowledged cost saving potential of the multiple drive technology, no previous work was reported on the methodology to realize a cost-effective design of multi-drive belt conveyors. This study investigates a design approach for multiple drive belt conveyors with the objective to achieve the lowest life cycle cost of multi-drive belt conveyors for a specified material transport task. For this purpose, an optimization model for the cost-effective design of multi-drive conveyor systems is formulated on the basis of the recommendations of the DIN 22101 and SANS 1313 standards. For a given number of intermediate drive stations, the proposed model optimizes a set of design parameters so that the minimum equivalent annual cost of a conveyor can be attained whilst handling the transport requirements and design conditions. The conveyor parameters optimized in this study are the rated powers of motors, the rated torques of gear reducers, the diameters and wrap angles of drive pulleys, the belt width, the belt speed, the lengths of the belt sections not nestled between drive pulleys, the spacings between idler rolls and the shell diameters and shaft diameters of idler rolls. For benchmark analysis purposes, a similar optimization model is also developed for the single drive technology. Described as mixed integer nonlinear programming (MINLP) problems, the two optimization models are solved using the MIDACO solver embedded in the MATLAB environment. The results of this study show the validity and effectiveness of the design model proposed for multi-drive belt conveyors. The results also indicate that the multiple drive technology is more beneficial for the conveying over long distances. The impact of the possible instability of inflation throughout the project lifetime is also investigated through three hypothetical scenarios, which involve a fixed inflation rate, a higher fluctuating inflation rate and a lower fluctuating inflation rate, respectively. The results of this sensitivity analysis show that the most cost-effective multi-drive belt conveyors obtained under a fixed inflation rate is robust enough against limited fluctuations of this parameter. / Dissertation (MEng)--University of Pretoria, 2017. / Electrical, Electronic and Computer Engineering / MEng / Unrestricted

The Federal Aviation Administration (FAA) is developing a new software information system -- the Surface Movement Advisor (SMA). This system development program has progressed through part of the system engineering process and is currently at a stage where additional funding will be required to complete the development. The budget for R&D at the FAA is tight and several new programs are vying for limited funds. To secure funding for further development the SMA system team must again demonstrate that it has a cost effective solution that is beneficial to the airlines and their passengers. The purpose of this project was to gather, structure, and analyze cost data and benefit information within the context of the systems engineering process as being practiced by the FAA and their SMA contractors. <p>The requirements for the SMA system are based on the fact that the developers have confirmed operational deficiencies concerning accurate and timely information about the status, position, and movement of commercial aircraft on the ground at the major airports in the country. This deficiency causes excessive and costly ground delays of aircraft. With proper information the ground controllers in the control towers will be able to direct ground traffic more efficiently and reduce the costly delays. The designers have confirmed the need for the system. They have developed feasible concepts, listed the requirements for the system, system specifications, and some preliminary designs. The systems engineers now must now decide among three design alternatives. <p>This project demonstrates a systems engineering approach to the evaluation of these design alternatives, selection of the preferred alternative and demonstration of possible benefits to justify further funding. This is the first cost and benefit analysis and many of the costs and benefits are best estimates. At later stages in the development cycle costs and benefits will be analyzed again using more current data, more accurate assumptions, and results from prototype testing and evaluation. The estimates will become more accurate in the detailed design phase in the future. / Master of Science

Master of Science

In today's society, the disposal of hazardous and non-hazardous waste is an ever growing problem. Legislation has become increasingly stringent with regard to protecting the environment from groundwater contamination. As documented by the EPA, the proportion of waste disposed of in landfills has steadily declined throughout the past thirty years due to source reduction, waste diversion to combustion facilities, and material recovery efforts. <p>This project examines the effects of material recovery levels on landfill life-cycle costs. A model has been developed to study the relationships between the operational costs, profit, and material recovery levels. The landfill in King George County, Virginia is used as the basis for studying the effects of increasing the current state required material recovery level from 25% to 50%. / Master of Science

Dectes texanus LeConte (Coleoptera: Cerambycidae) is a longhorn beetle species endemic to eastern United States. Originally described as a pest of weeds from the family Asteraceae, D. texanus has expanded its host range and is found infesting the stems of soybeans, Glycine max (L.) through the southwestern and middle United States. Female D. texanus chews a hole in the epidermis of a petiole and oviposits on it. Then, the D. texanus larva depletes all the pith of the stem making a tunnel down to the base of the plant and girdle the stem about 5 cm above the soil line. When a force is applied to the girdling point, generally weather related (i.e. strong winds), the plant lodges. While D. texanus phenology has been described for some states, this topic has yet to be explored in Kentucky. The objectives of this study were: 1) to describe the life cycle and behavior of D. texanus in soybeans in Western Kentucky, 2) to study the effect of the stem diameter on the incidence of D. texanus infestations, 3) to evaluate the susceptibility of full-season and double-crop soybeans to D.texanus infestations, 4) investigate the efficacy of seed treatment in reducing D. texanus infestations, 5) to determine effects of D. texanus larval feeding in the physiological yield of soybeans. The results of these studies showed that: 1) there was no distinct peak of D. texanus emergence detected in the 2018 and 2019 growing seasons and pupation period varied with year and location; the best sampling period for D. texanus population should occur between 1000 and 1600 hours during the peak season with either a 5-gallon white plastic bucket or sweep net; 2) the probability of finding D. texanus infesting soybeans was higher when the stem diameter is larger than 9 mm, and smaller than 11 mm; 3) double-crop soybeans had reduced infestations of D. texanus because these soybean plants are not a suitable host when D. texanus was active ovipositing and the pith was not fully developed; 4) seeds treated with imidacloprid did not influence D. texanus infestation on soybeans, larvae presence in main and lateral stems, and parasitism occurrences; and 5) D. texanus did not affect seeds and pods attributes (pod width, length, height and weight), and yield. The latter may occur because feeding of D. texanus larva does not interfere on photosynthesis or nutrient transportation during seed fill.

All kinds of products have economic, social and environmental impact throughout their entire life cycle. Today’s growing need for electronic devices contributes to the increasing problem within these fields.  The aim of this study is to investigate and determine the impact of a chosen Teracom Group product from a sustainability perspective and to develop recommendations regarding how to proceed, in order to reduce the impact of products. This study is mainly focusing on the environmental aspect of the concept of sustainability. A life cycle assessment (LCA) of a set-top box (STB) is conducted based on chosen indicators by using the software SimaPro. The goal of the assessment is to identify the phases within the life cycle with largest environmental impact and contribute to Teracom Group’s further sustainable work. 18 impact categories are included to express emissions and use of natural resources. The result clearly shows that the production phase has the largest environmental impact within categories such as terrestrial acidification, human toxicity, freshwater ecotoxicity, marine ecotoxicity, urban land occupation and metal resource depletion. The use phase affects the environment foremost within climate change, ozone depletion, terrestrial ecotoxicity, ionising radiation, agricultural land use, natural land transformation and water depletion. Transports and the waste scenario only have a small effect on certain categories. The experiences of this study are discussed, demonstrating the difficulty in making an LCA in the position of being at the company purchasing products, not at the company manufacturing them. The company has previously not focused enough on sustainability regarding products. An LCA performed by the supplier would be more reliable due to a better possibility of collecting accurate data. Communication and cooperation between the company and its suppliers are key solutions. Higher requirements during procurement should be put on the products, including demands on performed LCAs with clearly described references and methods, critically review by a third party.