A computer program is developed for the dynamic analysis of a spar platform coupled with mooring lines and risers in waves, winds, and currents. The new multi-contact analysis program is developed for the nonlinear multi-contact coupling between vertical risers and guide frames inside of the spar moon-pool. The program extends capability of the current coupled dynamic analysis program, WINPOST, by adding the capability of analyzing riser effects caused by the contact forces and moments from buoyancy-cans inside the spar moon-pool on the global spar motions. The gap between the buoyancy can and riser guide frames are modeled using three different types of nonlinear gap springs. The new riser model also considers the Coulomb damping between the buoyancy-cans and riser guide frames, and it also calculates the impact force on risers for use in fatigue analysis. The spar platform generally uses vertical risers with dry trees. However, as the water depth increases, the size of the buoyancy-can increases, and it makes installation more difficult. The pneumatic riser support system does not use buoyancy-cans and is an alternative solution to the buoyancy-can approach. The dynamic characteristics of pneumatic riser support system are studied by using the newly developed numerical analysis program. The damped Mathieu instability diagram for the damped Mathieu's equation is developed. Due to spar heave and pitch coupling, Mathieu's instability may become excited in long period waves. In the numerical analysis program, pitch and roll hydrostatic stiffness are recalculated for heave motion in every time step to check Mathieu's instability for the spar platform. Simplified vortex-induced vibration effects on the spar platform are considered in newly developed numerical analysis program, and the results are systematically compared with those of the original program WINPOST. The results in this paper show that the buoyancy-can effect significantly reduces the spar pitch motion, and the Coulomb damping effect also significantly reduces the spar heave motion. The buoyancy-can effect also plays an important role in Mathieu instability. The results also show that a pneumatic riser support system increases the spar heave motion and payload.

While wind energy has witnessed faster growth than any other renewable energy source in recent years, two issues—the decreasing availability of large land expanses for new wind farms and transmission difficulties arising from siting wind farms in remote regions far from load centers—have slowed down this growth considerably. Siting wind turbines offshore places the generating capacity closer to population and load centers; thus, reducing grid congestion. Also, at offshore sites, one can expect higher wind speeds, decreased turbulence, and reduced noise and visual impact constraints. Offshore wind turbines that have been built thus far have had foundations (such as monopiles or jacket structures) that have extended to the seabed. Such offshore wind turbines have thus been confined to shallow waters closer to the shore. Sites farther offshore provide better wind resources (i.e., less turbulence and smoother, stronger winds) while also reducing visual impact, noise, etc. However, deeper waters encountered at such sites make bottom-supported turbines less economical. Wind turbines mounted atop floating platforms are, thus, being considered for deeper water offshore sites. Various floating platform concepts are under consideration; the chief differences among them arise from the way they provide stability to counter the large mass of the rotor-nacelle assembly located high above the mean water level. Of these alternative concepts, the spar buoy platform is a deep draft structure with a low center of gravity, below the center of buoyancy. Reliability analysis of a spar buoy-supported floating offshore 5MW wind turbine based on stochastic simulation is the subject of this study. Environmental data from a selected deepwater reference site are employed in the numerical studies. Using time-domain simulations, the dynamic behavior of the coupled platform-turbine system is studied; statistics of tower and rotor loads as well as platform motions are estimated and critical combinations of wind speed and wave height identified. / text

Submitted by Sandro Dórea (sandrosdorea@gmail.com) on 2017-09-18T12:43:20Z No. of bitstreams: 1 Dissertação de Mestrado - Final.pdf: 2383138 bytes, checksum: f00dc7c79477929c8335c52d02715c28 (MD5) / Approved for entry into archive by Uillis de Assis Santos (uillis.assis@ufba.br) on 2017-09-20T18:47:39Z (GMT) No. of bitstreams: 1 Dissertação de Mestrado - Final.pdf: 2383138 bytes, checksum: f00dc7c79477929c8335c52d02715c28 (MD5) / Made available in DSpace on 2017-09-20T18:47:39Z (GMT). No. of bitstreams: 1 Dissertação de Mestrado - Final.pdf: 2383138 bytes, checksum: f00dc7c79477929c8335c52d02715c28 (MD5) / Faculdade Anísio Teixeira / Este trabalho pretende determinar uma função de produção capaz de melhorar o resultado operacional da unidade de abate e processamento de aves estudada, localizada no interior da Bahia. Diante do cenário complexo encontrado foram usadas as técnicas de pesquisa operacional e teoria das restrições para definir um novo mix de produção. Para entender as interferências na operação foram utilizadas as técnicas do SPAR – H, ferramenta originalmente aplicada em estudos de confiabilidade em usinas nucleares e que pode ser adaptada para outras indústrias tendo como objetivo detectar a interferência humana, e a distribuição de Weibull, que é utilizada largamente pela engenharia de confiabilidade para determinar a disponibilidade dos equipamentos. A partir do entendimento das relações homem - máquina que foram estabelecidas buscar-se-á propor ações para nortear a busca pela produção com o máximo de confiabilidade para alcançar o regime normal de operações. / This work aims to determine a production function capable of improving the operational result of the studied poultry slaughter and processing unit, located in the countryside of Bahia. Facing the complex scenario, it was used the operational research techniques and the theory of constraints to define a new mix production. In order to understand the interferences in the operation, the techniques of SPAR – H was used, a tool originally applied in reliability studies in nuclear power plants and that can be adapted for other industries with the objective of detecting human interference, and the Weibull distribution that are widely used by reliability engineering to determine the equipment availability. From the understanding of the man - machine relations that have been established it will be sought propose actions to guide the search for production with the maximum reliability to achieve the normal operations regime.

At present days agriculture has been looking for new technologies for quickly supplying the human needs in foods. It is undeniable that the use of machines in the agriculture as well as the discovery and application of new agricultural techniques or modern and efficient cultural methods allowed the increase of the production and agricultural productivity in the world, enlarging in a significant way, the income of the work, the areas of the cultures and the respective productions, reducing the hand of manual work in the accomplishment of the agricultural works, mainly the dangers to the human health. Due to those technological progresses there is a series of alternatives at the farmer's reach, but that, due to great speed in the innovations, he doesn't have enough information to choose for one or other more appropriate technique. That work had as subject to evaluate a new drag pulverization system (SPAR) as well as to compare it with the two more used systems which are: bars pulverizer and agricultural aviation. Three parameters were used to compare the systems and evaluate, operational capacity, mechanical damages and drops deposition. Regarding to the operational capacity the SPAR system was 100% superior on average to the pulverizer equipped with normal bars under tests conditions. Aerial application under tests conditions presents a superior operational capacity in relation to the two terrestrial systems. For mechanical damages doesn t exist any medium productivity difference among the systems, however, in grassy having between nodes as corn and sorghum should only be used the SPAR system in the initial phase of the culture before the between nodes appearance. The SPAR system has the larger penetration of the product in the inferior layer of the dossal. Within statistical terms didn't exist significant differences among the systems with fungicides application in soybean productivity / É inegável que o uso de máquinas na agricultura, bem como, a aplicação de novas técnicas agrícola, permitiu o aumento da produção e produtividade agrícola no mundo. Há uma série de alternativas a disposição do agricultor. Este trabalho serviu para avaliar um novo sistema de pulverização de arrasto (SPAR) e comparar com os dois sistemas mais utilizados que são: pulverizador de barras e aviação agrícola. Para avaliar e comparar os sistemas foram utilizadas três variáveis que foram: Desempenho operacional, danos mecânicos e deposição de gotas. Para a realização da análise de deposição de gotas foram utilizados papéis hidro-sensíveis, fixados nas entrelinhas e junto às linhas do dossel vegetativo a 30 e 60 cm de altura. Desta forma determinou-se à densidade de gotas e o DMV (Diâmetro médio volumétrico). Os danos mecânicos foram estimados com a determinação da produção em áreas com e sem amassamento pelo rodado do trator. Por diferença se obteve as perdas por danos mecânicos pelos sistemas terrestres. O sistema aéreo foi considerado como dano zero. Foi mensurado também o dano causado pelo arraste da mangueira de pulverização sobre as culturas pelo sistema SPAR. O desempenho operacional foi baseado nos tempos operativos, determinando capacidade de campo operacional e rendimento de campo. Para a avaliação do sistema SPAR foi realizada uma série de medições de desempenho operacional variando condições e tamanhos das áreas e sistemas de abastecimento. Quanto à capacidade operacional o sistema SPAR foi em média 100% superior ao pulverizador equipado com barras normais, nas condições dos testes. A aplicação aérea possui uma capacidade operacional superior aos dois sistemas terrestres. A redução da produtividade, por amassamento, é mais significativa pelo sistema de barras. Em gramíneas com entrenós, como milho e sorgo, deve-se utilizar o sistema SPAR somente na fase inicial da cultura antes do surgimento dos entrenós. O sistema SPAR possui maior penetração do produto na camada inferior do dossel. Estatisticamente não existiram diferenças significativas entre as variáveis utilizadas para diferenciar os sistemas avaliados, na aplicação de fungicidas em produtividade de soja

Made available in DSpace on 2014-06-12T15:53:07Z (GMT). No. of bitstreams: 2 arquivo5192_1.pdf: 788582 bytes, checksum: 9c493ee2ba6857656c0a20883bb05c1f (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2006 / A relação biológica de leveduras industrialmente importantes do complexo Saccharomyces sensu stricto causa equívoco na correta identificação das leveduras. Por isso, este trabalho apresenta a técnica de PCR - fingerprinting com diferentes marcadores que identificaram com eficiência as verdadeiras espécies do complexo Saccharomyces sensu stricto e indicaram os híbridos naturais isolados de processos industriais. Linhagens tipo, linhagens comerciais de vinho e leveduras isoladas de vinho artesanal foram submetidas à análise de PCR - fingerprinting usando oligonucleotídeos únicos (SPAR) e análise de restrição de genes ribossomais e estruturais. Todas as seis espécies reconhecidas do complexo Saccharomyces sensu stricto foram discriminadas e erros na taxonomia anterior das leveduras de vinho foram observados. Além disso, estes marcadores SPAR mostraram a complexidade da constituição híbrida dos isolados industriais. O uso de marcadores SPAR pode ajudar na identificação de leveduras isoladas da indústria e do meio ambiente dentre uma das seis espécies do complexo Saccharomyces sensu stricto e seus híbridos interespecíficos, e na reclassificação de linhagens depositadas em coleções de leveduras. Embora este conjunto de marcadores falhe em determinar a contribuição de parentais no processo de hibridização, pode eficientemente traçar a dispersão de leveduras híbridas que foram originadas em eventos simples de hibridização. O padrão único gerado pelos marcadores SPAR foi bastante eficiente no monitoramento da população de leveduras durante o processo de fermentação industrial e pode detectar a aproximação de leveduras híbridas em cada meio ambiente

The current method for house valuations in mortgage portfolio models corresponds to applying a residential property price index (RPPI) to the purchasing price (or last known valuation). This thesis introduces an alternative house valuation method, which combines the current one with the bank's customer data. This approach shows that the gap between the actual house value and the current estimated house value can to some extent be explained by customer attributes, especially for houses where the homeowner is a defaulted customer. The inclusion of customer attributes can either reduce false overestimation or predict whether or not the current valuation is an overestimation or underestimation. This particular property is of interest in credit risk, as false overestimations can have negative impacts on the mortgage portfolio. The statistical methods that were used in this thesis were the data mining techniques regression and clustering. / De modeller och tillvägagångssätt som i dagsläget används för husvärdering i bolåneportföljen bygger på husprisindexering och köpesskilling. Denna studie introducerar ett alternativt sätt att uppskattta husvärdet, genom att kombinera dagens metod med bankens egna kunddata. Det här tillvägagångssättet visar på att gapet mellan det faktiska och det uppskattade husvärdet kan i viss mån förklaras av kunddata, framförallt där husägaren är en fallerad kund. Inkluderandet av kunddata kan både minska dagens övervärdering samt predicera huruvida dagens uppskattning är en övervärdering eller undervärdering. För fallerade kunder gav den alternativa husvärderingen ett mer sanningsenligt uppskattat värde av försäljningspriset än den traditionella metoden. Denna egenskap är av intresse inom kreditrisk, då en falsk övervärdering kan ha negativa konsekvenser på bolåneportföljen, framförallt för fallerade kunder. De statistiska verktyg som användes i denna studie var diverse regressionsmetoder samt klusteranalys.

The paper compares electricity production between the semi-submersible and the spar-buoy floating wind turbine systems under normal, stochastic and extreme wind conditions at Utsira Nord site located on the Norwegian continental shelf in the North Sea. The analysis of complex behavior of the floating wind turbine system and the fluid-structure interaction is performed in aero-servo-hydro-elastic code ASHES. The results indicate a slightly better energy performance of the semi-submersible than the spar in all load cases but one. The pitch and heave degrees of freedom are evaluated as the most relevant for the power output. It is shown that pitch and heave platform motions have smaller displacement in the semi-submersible floater than in the spar under average environmental conditions and at the rated wind speed operating range. The simulation also confirmed that the energy yield is very sensitive to the magnitude of the loads: the spar performed best under mild environmental conditions, while the semi-submersible was better under medium environmental conditions. Small difference in energy yield is attributed to the same baseline blade and external controller properties used for both floaters where generator torque was kept constant to limit the power excursions above the rated power. The method proposed under this paper has demonstrated that a good approximation of the energy performance of the floating wind turbine system can be performed in a fast and effective manner.

Thesis (MBA)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: Ongoing business sustainability today is one of the major issues facing the management of organizations. How to remain in the profit zone, that area where a company will be allowed to make high profit in its industry, is a constant challenge. Continued profitability in a fast changing industry, where the profit zone moves as competitors offer the same solutions, requires constant innovation, implementation of new ideas and heavy financial commitments. The key is to identify clear and rational business design choices that are responsive to customers and that will ensure profitability. This document will illustrate how the four major food retail companies in South Africa, and their visionary leaders, have reinvented their business designs in ways that kept or returned them to the profit zone. Shoprite's target market is the middle to lower income group. The company has built up core competencies within its business to serve this segment. There are currently a number of issues facing Shoprite's core market, and as a result the company is diversifying its income streams to be less dependant on a vulnerable target market. . The visionary leadership of Raymond Ackerman, who applied principles of customer sovereignty long before his peers, has resulted in one of the best-run companies in South Africa. Pick 'n Pay's ability lies within the middle to upper segment of the market. The company has built its business on one core element - the customer, and has adapted the company business design to meet the needs of the customer and capture value . .Spars' philosophy of giving the small retailer the power to compete with the larger retailer, who buys in bulk, has proved to be a successful formula and is threatening the traditional hierarchy. Owners who are in close contact to customers have the flexibility to align their businesses with the customer requirements. 'Woolworths has one of the strongest brands in the South African retail industry. However, the company has in recent years been in serious trouble having lost its way because it lost touch with its customers. Concentrating back on the core customers and building back confidence in its goods, have taken considerable focus. Each of the business designs are built on a deep understanding of what the customer needs are of the target market they serve and how they will be allowed to make a profit. / AFRIKAANSE OPSOMMING: Een van die grootste knelpunte vir organisasies vandag is volhoubare besigheidsbestuur. Die uitdaging is om in die area te bly waar die organisasie toegelaat sal word om hoë wins te maak. Voortgesette winsgewendheid in 'n industrie waar die wins area veskuif as gevolg van mededingers wat oplossings naboots, vereis voortdurende vernuwing en strawwe finansiële verpligtinge. Die sleutel is om duidelike en rasionele besigheidsontwerpbesluite te neem wat kliente behoeftes aanspreek en wat na 'n wins sal lei. Hierdie dokument beskryf hoe die vier groot voedselhandelaars en hulle leiers hul besighede herontwerp het sodat hulle winsgewend kan bly. Shoprite se teiken mark is die middel - tot lae inkomste groep. Die firma het kern bevoegdhede binne sy besigheid ontwikkel om hierdie segment te bedien. Shoprite diversifeer huidiglik sy inkomste stroom as gevolg van die kwesbaarheid van sy teiken mark. Pick 'n Pay word as een van Suid Afrika se beste bestuurde firmas beskou. Die sukses word toegeskryf aan die leierskap van Raymond Ackerman wat die beginsels van kliënte soewereiniteit lank voor sy portuurgroep geïmplimenteer het. Pick 'n Pay se fokus is die middel - tot hoë inkomste groep. Die firma is op een kern element gebou, die kliënt, en sy besigheids ontwerp is aangepas om die behoeftes van die kliënt te bevredig. Spar se filosofie is om die kleiner handelaar in 'n posisie te stel om met die groot handelaar, wat in grootrnaat aankoop, te kan meeding. Die groei wat Spar toon bedreig die traditionele hiërargie en bewys die sukses van hierdie formule. Winkel eienaars wat noue kontak met kliënte het, kan hulle besighede aanpas om in kliënte se behoeftes te voorsien. Woolworths het een van die sterkste handelsmerke in die Suid Afrikaanse handels industrie. Die firma was in die laaste paar jaar in groot moeilikheid omdat hy tred verloor het met sy kliënte. Deur weer te konsentreer op die kern kliënt en om vertroue op te bou in sy goedere het beduidende fokus vereis. Elk van die besigheids ontwerpe is gebou op 'n intieme begrip van die behoeftes van die teiken mark wat bedien word en hoe die firma toegelaat sal word om 'n wins te maak.

The development of the layer-by-layer (LbL) technique has turned out to be an efficient way to physically modify the surface properties of different materials, for example to improve the adhesive interactions between fibers in paper. The main objective of the work described in this thesis was to obtain fundamental data concerning the adhesive properties of wood biopolymers and LbL films, including the mechanical properties of the thin films, in order to shed light on the molecular mechanisms responsible for the adhesion between these materials. LbLs constructed from poly(allylamine hydrochloride) (PAH)/poly(acrylic acid) (PAA), starch containing LbL films, and LbL films containing nanofibrillated cellulose (NFC) were studied with respect to their adhesive and mechanical properties. The LbL formation was studied using a combination of stagnation point adsorption reflectometry (SPAR) and quartz crystal microbalance with dissipation (QCM-D) and the adhesive properties of the different LbL films were studied in water using atomic force microscopy (AFM) colloidal probe measurements and under ambient conditions using the Johnson-Kendall-Roberts (JKR) approach. Finally the mechanical properties were investigated by mechanical buckling and the recently developed SIEBIMM technique (strain-induced elastic buckling instability for mechanical measurements). From colloidal probe AFM measurements of the wet adhesive properties of surfaces treated with PAH/PAA it was concluded that the development of strong adhesive joints is very dependent on the mobility of the polyelectrolytes and interdiffusion across the interface between the LbL treated surfaces to allow for polymer entanglements. Starch is a renewable, cost-efficient biopolymer that is already widely used in papermaking which makes it an interesting candidate for the formation of LbL films in practical systems. It was shown, using SPAR and QCM-D, that LbL films can be successfully constructed from cationic and anionic starches on silicon dioxide and on polydimethylsiloxane (PDMS) substrates. Colloidal probe AFM measurements showed that starch LbL treatment have potential for increasing the adhesive interaction between solid substrates to levels beyond those that can be reached by a single layer of cationic starch. Furthermore, it was shown by SIEBIMM measurements that the elastic properties of starch-containing LbL films can be tailored using different nanoparticles in combination with starch. LbL films containing cellulose I nanofibrils were constructed using anionic NFC in combination with cationic NFC and poly(ethylene imine) (PEI) respectively. These NFC films were used as cellulose model surfaces and colloidal probe AFM was used to measure the adhesive interactions in water. Furthermore, PDMS caps were successfully coated by LbL films containing NFC which enabled the first known JKR adhesion measurements between cellulose/cellulose, cellulose/lignin and cellulose/glucomannan. The measured adhesion and adhesion hysteresis were similar for all three systems indicating that there are no profound differences in the interaction between different wood biopolymers. Finally, the elastic properties of PEI/NFC LbL films were investigated using SIEBIMM and it was shown that the stiffness of the films was highly dependent on the relative humidity. / <p>QC 20110923</p>

In this paper, a new algorithm for utilizing energy storage is proposed and applied on floating wind turbine economics. The proposed algorithm’s decision making on storing energy or selling electricity onto the grid is based on the electricity price, which makes it unique and different from similar algorithms. From the literature review, it was concluded Ocean Renewable Energy Storage to be most suitable with the Spar-Type and Semi-Submersible floating wind turbine to which the paper is based upon. The objective of this paper is to find the suitable ratio of energy storage versus wind farm, find the product of increase in wholesale, and evaluate whether the proposed method makes the hybrid economically sound. The algorithm was applied on spot-price data from Denmark due to its large share of wind energy with wind data from off the coast of Morro Bay in California, USA. Additionally, a sensitivity analysis is applied to evaluate to energy storage cost impact as well as evaluate the algorithm by lowering the required energy storage size.   Using the algorithm, the wind farm must account for nine days’ worth of energy production with a product of energy storage versus wind farm ratio of 1.42. The wholesale price increased with 11.9-21.5% for the four years studied, however, all financial results favored not utilizing energy storage. By the results derived from the sensitivity analysis, it was concluded that with future cost reductions, the algorithm will still favor no energy storage. However, by fine tuning the algorithm to reduce the need for storage, positive financial result might be achievable. The key to achieve a profitable result seems to rely on minimizing the need for energy storage, to which the proposed algorithm fail to achieve. Conclusively, spot-price decision-based energy storing is not economically sound.