Global ETD Search

11	En studie om hur vägräcken påverkar trafiksäkerheten / A study about the impact of road crash barriers on road security Pettersson, Lina, Ben Youssef Hamzo, Nidal January 2015 (has links) Syftet med den här studien är att undersöka lutning och höjd för vägräcken och hur dessa faktorer påverkar trafiksäkerheten. Rapporten syftar även till att ta upp den säkerhetsproblematik som rör MC-trafikanter då underglidningsskydd inte får plats att monteras under vägräckena. Genom forskning i Trafikverkets och Statens väg- och transportinstituts databaser samt intervjuer tillsammans med föreningarna SMC (Svenska MotorCyklister) och SVBRF (Sveriges bro- och vägräckesförening) har det framkommit överensstämmande resultat gällande den nationella, svenska standarden SS EN-1317. Den standarden vi använder idag, SS EN-1317 ger en monteringshöjd på 450 millimeter till bärande balk. Vilket ger problematik vid montering av underglidningsskydd och påverkar trafiksäkerheten negativt. I nuläget hålls en vetenskaplig forskning gällande underglidningsskydd som testas på fyra olika vägar i Sverige, bland annat i Åkersberga, Stockholm. / The purpose of this study is to survey the incline and height of crash barriers and how these two factors affect traffic security. The study also serves the purpose of bringing up problems in traffic security due to lack of space under crash barriers for installation of slide guards for motorcyclists. Research in the databases of the Swedish Transportation Administration (Trafikverket), Road and Transport Institute (VTI), the Associations of Swedish Motor Cyclists (föreningen Sveriges MotorCyklister), and Swedish Bridge and Crash Barrier Association (Sveriges Bro- och Vägräckesförening) has shown corresponding results with the Swedish standard SS EN-1317. The standard in use today, SS EN-1317, affects traffic security negatively due to the height of assemblage of the carrying beam in crash barriers being 450 millimeters. At the time of writing research is being conducted regarding slide guards on four different roads in Sweden with one located in Åkersberga, Stockholm. Crash barriers incline height motorcycle protection system MPS Standard SS EN- 1317 and motorcycles Vägräcken Lutning Höjd Underglidningsskydd Standard SS EN-1317 och MC- trafikanter Construction Management Byggproduktion
12	Counter-flow Ion Mobility Analysis: Design, Instrumentation, and Characterization Agbonkonkon, Nosa 14 November 2007 (has links) (PDF) The quest to achieve high resolution in ion mobility spectrometry (IMS) has continued to challenge scientist and engineers in the field of separation science. The low resolution presently attainable in IMS has continued to negatively impact its utility and acceptance. Until now, efforts to improve the resolution have mainly focused on better instrumentation and detection methods. However, since the resolution of IMS is diffusion limited, it makes sense to address this limitation in order to attain high resolution. This dissertation presents a new IMS technique, which utilizes a high electric field and opposing high gas flow velocity with the aim to improve resolution. This approach essentially reduces the residence time of ions in the analyzer. This new technique is called "counter-flow ion mobility analysis" (CIMA). Theoretical modeling of this new technique predicted that a resolution of over 1000 is possible, which is over one order of magnitude better than that of conventional IMS techniques currently used. A wind tunnel was designed and constructed to produce a plug gas flow profile that is needed for CIMA. The test region of the wind tunnel was used as the CIMA analyzer region and was constructed from power circuit boards, PCBs, (top and bottom walls) and conductive plastic side walls. An inclined electric field was created by applying suitable voltages to multiple electrode traces on the PCBs. This inclined field, when resolved into its x- and y-components, was used to oppose the counter-gas flow and transport the ions to the detector, respectively. The results obtained did not show an improvement over conventional IMS techniques because of a limitation in the voltage that could be applied to the analyzer region. However, the results predict that high resolution is possible if (1) the ratio of the electric fields in the horizontal (x direction) to the vertical (y direction) is within the range of 2--0.5, (2) very high electric field and high gas flow velocities are applied, and (3) wall effects in the counter-flow gas profile are eliminated. While the resolution obtained using the present instrumentation is far from what was predicted, the foundation for ultimately achieving high resolution has been laid. The use of a wind tunnel has made the instrumentation possible. As far as the author knows, this is the first time a wind tunnel has been used in chemical measurement instrumentation. Chapter 5 of this dissertation, reports a method developed for predicting the reduced mobility constants, of chemical compounds. This method uses a purely statistical regression analysis for a wide range of compounds which is different from similar methods that use a neural network. The calculated value for this method was 87.4% when calculated values were plotted against experimental K0 values, which was close to the value for the neural network method (i.e., 88.7%). Analytical Chemistry Instrumentation Chemical Analysis Separation Detection Ion Mobility Spectrometry IMS FAIMS DMA Analyzers Wind Tunnel Counter-flow Analyzer CIMA Mass Spectrometry Chromatography Faraday Detectors Uniform Gas Flow Velocity Incline Potential and Electric Fields Analyzer Designs Fluid Flow simulation Modeling Electric Field in Analyzer Biochemistry Chemistry
13	Oceanographic Considerations for the Management and Protection of Surfing Breaks Scarfe, Bradley Edward January 2008 (has links) Although the physical characteristics of surfing breaks are well described in the literature, there is little specific research on surfing and coastal management. Such research is required because coastal engineering has had significant impacts to surfing breaks, both positive and negative. Strategic planning and environmental impact assessment methods, a central tenet of integrated coastal zone management (ICZM), are recommended by this thesis to maximise surfing amenities. The research reported here identifies key oceanographic considerations required for ICZM around surfing breaks including: surfing wave parameters; surfing break components; relationship between surfer skill, surfing manoeuvre type and wave parameters; wind effects on waves; currents; geomorphic surfing break categorisation; beach-state and morphology; and offshore wave transformations. Key coastal activities that can have impacts to surfing breaks are identified. Environmental data types to consider during coastal studies around surfing breaks are presented and geographic information systems (GIS) are used to manage and interpret such information. To monitor surfing breaks, a shallow water multibeam echo sounding system was utilised and a RTK GPS water level correction and hydrographic GIS methodology developed. Including surfing in coastal management requires coastal engineering solutions that incorporate surfing. As an example, the efficacy of the artificial surfing reef (ASR) at Mount Maunganui, New Zealand, was evaluated. GIS, multibeam echo soundings, oceanographic measurements, photography, and wave modelling were all applied to monitor sea floor morphology around the reef. Results showed that the beach-state has more cellular circulation since the reef was installed, and a groin effect on the offshore bar was caused by the structure within the monitoring period, trapping sediment updrift and eroding sediment downdrift. No identifiable shoreline salient was observed. Landward of the reef, a scour hole ~3 times the surface area of the reef has formed. The current literature on ASRs has primarily focused on reef shape and its role in creating surfing waves. However, this study suggests that impacts to the offshore bar, beach-state, scour hole and surf zone hydrodynamics should all be included in future surfing reef designs. More real world reef studies, including ongoing monitoring of existing surfing reefs are required to validate theoretical concepts in the published literature. Aramoana Beach Dunedin (New Zealand) ArcGIS ArcSDE artificial surfing reef backscatter Baseline Data Collection bathymetry bathymetric surveying beach morphodynamics beach-state and morphology breaking wave height coastal engineering coastal environment coastal management coastal monitoring coastal processes coastal structures currents economic value EIA environmental data management environmental impact assessment geographic information systems geoid geomorphic surfing break categorisation GIS groin hydrodynamic modelling hydrographic surveying hydrography ICZM incline plane modelling integrated coastal zone management Main Beach Mount Maunganui (New Zealand) Manu Bay Boat Ramp Raglan (New Zealand) measuring water levels morphological coupling multibeam echo soundings oceanography offshore wave transformations Palm Beach Reefs Gold Coast (Australia) RTK GPS salient surf zone hydrodynamics surfing break components surfing reefs surfing tourism surfing wave climate surfing wave parameters Tay Street Mount Maunganui (New Zealand) wave breaking intensity wave climate wave focusing wave modelling wave peel angle wave section length wind effects on waves

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