Trends in Income and Price Elasticities of Transport Demand (1850-2010)

40 p.

Lehiaketa motor baten direkzio piparen diseinua

[EU]Hurrengo orrialdeetan aurkezten den proiektu honetan, lehiaketa motor baten direkzio piparen diseinua proposatzen da zeinak Moto Engineering Foundation fundazioak sustatutako nazioarteko Motostudent txapelketan parte hartzeko motorrera egokituta egon beharko den. Honako helburu honekin beraz, direkzio piparen diseinu egoki bat egin ahal izateko piezak sufrituko dituen karga egoerak aurreikusi beharko ditugu hauen arabera jasan beharreko tentsio egoerak aztertu ahal izateko. Piezaren tentsioen analisia aurrera eraman beharko da beraz, diseinaturiko piezaren funtzionamendu egokia ziurtatu ahal izateko. Historian zehar existitutako diseinu modelo ezberdinak eta baita gaur egunean gehien erabilitakoak ere aurkeztu eta gero, gure kasura hobekien moldatuko zaion adibidetik ekingo zaio diseinuari, aldez aurretik eskuratutako datu eta errodamenduetatik abiatuz. Horrenbestez, oinarritzat hartutako direkzio sistema modeloa eta bestelako elementuen neurriak datutzat hartuta, tija zein norabide ardatzarena esate baterako, direkzio piparen hasierako geometria definituko da. Eskuragarri ditugun analisi metodo ezberdinak aztertu eta gure kasura hobekien moldatzen dena aukeratu eta eraikitako piezari aplikatuko zaio. Lorturiko emaitzen arabera hasiera batean planteaturiko diseinua onartu edo baztertzea erabaki beharko dugu. Beraz, gure diseinua optimizatuz joateko aukera izango dugu, baldintzak eta betebeharrak egiztatuko dituen amaierako pieza diseinua lortu arte. Bukatzeko, proiektuari itxiera emango dion atala aurkeztuko da, hala nola, proiektuaren garapenean zehar lorturiko emaitzak eta ondorioak biltzen dituen atala non lorturiko direkzio piparen funtzionamendu egokia bermatzen dituzten parametroak aurkeztuko diren. Gainera, direkzio sistemaren funtsezko atala izango diren errodamenduen kalkulu eta aukeraketa bideratuko da baita ere.

Velocity resolved - scalar modeled simulations of high Schmidt number turbulent transport

The objective of this thesis is to develop a framework to conduct velocity resolved - scalar modeled (VR-SM) simulations, which will enable accurate simulations at higher Reynolds and Schmidt (Sc) numbers than are currently feasible. The framework established will serve as a first step to enable future simulation studies for practical applications. To achieve this goal, in-depth analyses of the physical, numerical, and modeling aspects related to Sc>>1 are presented, specifically when modeling in the viscous-convective subrange. Transport characteristics are scrutinized by examining scalar-velocity Fourier mode interactions in Direct Numerical Simulation (DNS) datasets and suggest that scalar modes in the viscous-convective subrange do not directly affect large-scale transport for high Sc. Further observations confirm that discretization errors inherent in numerical schemes can be sufficiently large to wipe out any meaningful contribution from subfilter models. This provides strong incentive to develop more effective numerical schemes to support high Sc simulations. To lower numerical dissipation while maintaining physically and mathematically appropriate scalar bounds during the convection step, a novel method of enforcing bounds is formulated, specifically for use with cubic Hermite polynomials. Boundedness of the scalar being transported is effected by applying derivative limiting techniques, and physically plausible single sub-cell extrema are allowed to exist to help minimize numerical dissipation. The proposed bounding algorithm results in significant performance gain in DNS of turbulent mixing layers and of homogeneous isotropic turbulence. Next, the combined physical/mathematical behavior of the subfilter scalar-flux vector is analyzed in homogeneous isotropic turbulence, by examining vector orientation in the strain-rate eigenframe. The results indicate no discernible dependence on the modeled scalar field, and lead to the identification of the tensor-diffusivity model as a good representation of the subfilter flux. Velocity resolved - scalar modeled simulations of homogeneous isotropic turbulence are conducted to confirm the behavior theorized in these a priori analyses, and suggest that the tensor-diffusivity model is ideal for use in the viscous-convective subrange. Simulations of a turbulent mixing layer are also discussed, with the partial objective of analyzing Schmidt number dependence of a variety of scalar statistics. Large-scale statistics are confirmed to be relatively independent of the Schmidt number for Sc>>1, which is explained by the dominance of subfilter dissipation over resolved molecular dissipation in the simulations. Overall, the VR-SM framework presented is quite effective in predicting large-scale transport characteristics of high Schmidt number scalars, however, it is determined that prediction of subfilter quantities would entail additional modeling intended specifically for this purpose. The VR-SM simulations presented in this thesis provide us with the opportunity to overlap with experimental studies, while at the same time creating an assortment of baseline datasets for future validation of LES models, thereby satisfying the objectives outlined for this work.

Band structure and transport properties of simple cubic tellurium-base alloys

The electrical transport properties and lattice spacings of simple cubic Te-Au, Te-Au-Fe, and Te-Au-Mn alloys, prepared by rapid quenching from the liquid state, hove been measured and correlated with a proposed bond structure. The variations of superconducting transition temperature, absolute thermoelectric power, and lattice spacing with Te concentration all showed related anomalies in the binary Te-Au alloys. The unusual behavior of these properties has been interpreted by using nearly free electron theory to predict the effect of the second Brillouin zone boundary on the area of the Fermi surface, and the electronic density of states. The behavior of the superconducting transition temperature and the lattice parameter as Fe and Mn ore added further supports the proposed interpretation as well as providing information on the existence of localized magnetic states in the ternary alloys. In addition, it was found that a very distinct bond structure effect on the transition temperatures of the Te-Au-Fe alloys could be identified.

Lehiaketako motor baten erditxasiaren diseinua

[EU]Proiektu honek lehiaketarako moto baten erditxasia garatzen du, baita txasira lotuta egongo den modua ere. Erditxasia pieza estruktural bat da eta nahiz eta agian beharrezkoa ez izan lehiaketako moto batean, izan ere hauetan pilotuek ipurdia oso aurrean kokatzen dute pisua txasira bideratuz, moto guztiek duten atal bat da eta pertsonaren pisua eta honek egiturari eragiten dizkion indar eta esfortzuak eusteko erabiltzen da. Kasu batzuetan txasiaren beraren barnean egoten da zati hau eta beraz dena pieza bat izaten da, baina gure kasuan biak, erditxasia eta txasia elkarri lotuta egongo dira. Hasteko erditxasi hau zein eratara fabrikatua izan daitekeen aztertuko da(hodi, txapa…), eta modu bakoitzaren abantailak eta desabantailak ikusi beharko dira azkenik nola egingo den aukeratzeko. Honela gure piezaren eboluzio bat emango da guk behar ditugun exijentzia teknikoak bete ditzan eta ekonomikoki ere bideragarria izan dadin. Amaitzeko pieza bere lekuan bermatzeko beharko diren elementu laguntzaileak ere kalkulatu edo aukeratu beharko dira, lehiaketan dugun portaera guk nahi duguna izan dadin.

Lehiaketa motor baten atzealde-suspentsio sistema doigarri baten elementuen diseinua

[EU]Proiektu hau lehiaketa motor baten atzealde-suspentsio sistema doigarri baten elementuen diseinuan datza. Luzeran erregulagarria izango den tirantea eta suspentsio triangelua diseinatu eta optimizatuko dira. Diseinuak ahalik eta pisu txikiena izatea ahalbidetzen duten makinen elementuak (errotulak eta errodamenduak) aukeratuko dira. Lanaren garapenerako Motostudent izeneko lehiaketatik hartutako datu errealak erabiliko dira. Suspentsio sistemaren diseinua Creo2.0 (lehengo Pro-Engineer) software-arekin egingo da. Bestalde, beste software batzuk ere erabiliko dira, hala nola, Working Model 2D eta ANSYS, sistemaren analisia errazteko.

Metodologia para conversão de veículos equipados com motores a combustão interna para tração elétrica: aplicação de motor síncrono de ímã permanente com fluxo magnético radial a um furgão, Brasil. 2009.

Questões climáticas, atmosféricas e de poluição ambiental têm tornado o uso final da energia assunto de interesse mundial. Sistemas com tração elétrica oferecem a oportunidade de redução de emissões. O mix de energia caracterizado pela matriz energética brasileira viabiliza o desenvolvimento desta tecnologia. É desenvolvida aqui uma metodologia para conversão de veículos equipados com motores a combustão interna para tração elétrica. A metodologia considera fatores como o peso e tamanho, o torque de partida, transmissão e potência, entre outros. Ferramentas matemáticas e a prática corrente fornecem a base para a elaboração deste trabalho, que descreve a análise de desempenho de veículos elétricos, os componentes utilizados, as equações mecânicas e os critérios para escolha do veículo ideal para conversão. É apresentada a execução de um projeto de conversão de uma Kombi para tração elétrica, cujo objetivo tem caráter educativo, buscando assim promover os benefícios da tecnologia veicular elétrica. Para viabilização do experimento, o trabalho conclui que é necessário ampliar a demanda por nacionalização de tecnologia, o que tornaria o projeto uma realidade comercialmente viável. Além disto, há necessidade de políticas públicas para o incentivo da tecnologia veicular elétrica no Brasil. Este trabalho apresenta uma contribuição para converter veículos para tração elétrica, visto que sistematiza as etapas de projeto, a partir das quais outros poderão seguir, utilizando componentes encontrados no mercado nacional.

A GIS-based model of soil erosion and transport

Soil erosion is a natural process that occurs when the force of wind, raindrops or running water on the soil surface exceeds the cohesive forces that bind the soil together. In general, vegetation cover protects the soil from the effects of these erosive forces. However, land management activities such as ploughing, burning or heavy grazing may disturb this protective layer, exposing the underlying soil. The decision making process in rural catchment management is often supported by the predictive modelling of soil erosion and sediment transport processes within the catchment, using established techniques such as the Universal Soil Loss Equation [USLE] and the Agricultural Nonpoint Source pollution model [AGNPS]. In this article, the authors examine the range of erosion models currently available and describe the application of one of these to the Burrishoole catchment on the north-west coast of Ireland, which has suffered heavy erosion of blanket peat in recent years.

Factors influencing the downstream transport of sediment in the Lough Feeagh catchment, Burrishoole, Co. Mayo, Ireland

Research laboratories in the Burrishoole catchment have been the focus of salmonid research since 1955. One aspect of the research has been to monitor the number of salmon and sea trout migrating to sea as smolts and returning to the catchment as adults. In the early 1990s it became clear that the smolt output from the catchment had declined over the previous two decades. At about the same time the presence of fine particles of peat silt in the hatchery became increasingly apparent and led to a higher incidence of mortality of young fry. These observations and management difficulties led to a study of silt transport in the surface waters of the catchment, which is described in this article. The authors describe geology, soils, climate and hydrology of Burrishoole before examining the sediment deposition in Lough Feeagh.

Modelling soil erosion and transport in the Burrishoole catchment, Newport, Co. Mayo, Ireland

The Burrishoole catchment is situated in County Mayo, on the northwest coast of the Republic of Ireland. Much of the catchment is covered by blanket peat that, in many areas, has become heavily eroded in recent years. This is thought to be due, primarily, to the adverse effects of forestry and agricultural activities in the area. Such activities include ploughing, drainage, the planting and harvesting of trees, and sheep farming, all of which are potentially damaging to such a sensitive landscape if not managed carefully. This article examines the sediment yield and hydrology of the Burrishoole catchment. Flow and sediment concentrations were measured at 8-hourly intervals from 5 February 2001 to 8 November 2001 with an automatic sampler and separate flow gauge, and hourly averages were recorded between 4 July 2002 and 6 September 2002 using an automatic river monitoring system [ARMS]. The authors describe the GIS-based model of soil erosion and transport that was applied to the Burrishoole catchment during this study. The results of these analyses were compared, in a qualitative manner, with the aerial photography available for the Burrishoole catchment to see whether areas that were predicted to contribute large proportions of eroded material to the drainage network corresponded with areas where peat erosion could be identified through photo-interpretation.

The transport of aquatic animals by birds. [Translation from: Binnengewaesser 18, 156-159, 1950.]

A great deal has been written on the part which birds play in the dispersal of freshwater fauna. This article summarises literature on the dispersal of aquatic animals by birds and aquatic insects.