• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 168
  • 58
  • 52
  • 24
  • 13
  • 12
  • 9
  • 4
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 410
  • 60
  • 48
  • 39
  • 39
  • 35
  • 33
  • 29
  • 26
  • 26
  • 26
  • 26
  • 25
  • 24
  • 24
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

El- och hybridbilar: allmänhetens medvetenhet och inställning

Viktoriya, Vennberg January 2018 (has links)
With the increasing rate of pollution from transports with fossil fuel, greater active action is required in the form of many measures from the global community to reduce the use of diesel and gasoline driven vehicles. The purpose of the study was to examine the public awareness and attitudes towards electric driven vehicles, as well as the factors important to the public when purchasing such vehicles. At the same time, a survey was carried out to identify possible differences in attitude between individuals who had electric driven vehicles and those who had gasoline or diesel driven cars. Finally, the government subsidies were examined in order to evaluate whether they affect the public willingness to buy electric driven vehicles. The survey was conducted in Sweden and was based partially on a poll and partially on interviews. The result of this study showed that there is a great interest for the general public towards electric driven vehicles, and the majority who took part in the survey was aware of the positive effects of electric driven vehicles. The comparison between the two groups showed that there is a significant difference between the attitudes to the electric vehicles. Among other things, there are differences regarding the electric vehicles' future in Sweden and also differences in the attitude to the price of the electric vehicle. However, there is no difference between the attitudes of the two groups regarding environmental friendliness and the importance of the state subsidy.
22

The Icelandic example : planning for hydrogen fueled transportation in Oregon /

Fisher, Jeffrey Dean, January 2009 (has links)
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 85-91). Also available online in Scholars' Bank.
23

Mechanisms influencing railway wheel squeal excitation in large radius curves

Fourie, Daniël Johannes 31 July 2012 (has links)
M.Ing. / Sound pressure levels exceeding acceptable limits are being generated by trains travelling on the 1000 m radius curved railway line past the town of Elands Bay. Unacceptable sound levels are attributed mainly to top of rail wheel squeal. Top of rail wheel squeal belongs to the family of selfinduced vibrations and originates from frictional instability in curves between the wheel and the rail under predominantly saturated lateral creep conditions. In small radius curves, saturated lateral creep conditions occur due to the steering of railway wheelsets with large angles of attack. Given the large curve radius and the utilisation of self-steering bogies on the Sishen-Saldanha Iron Ore railway line, curve squeal is a highly unexpected result for the 1000 m radius curved railway line. This is because curving of bogies in large radius curves are achieved without high wheelset angles of attack leading to saturated creep conditions. An experimental and analytical investigation was carried out to identify the mechanisms influencing the generation of wheel squeal in large radius curves. Simultaneous measurement of sound pressure and lateral wheel-rail forces were made during regular train service in one of the two 1000 m radius curves at Elands Bay to characterise the bogie curving behaviour for tonal noise due to wheel squeal occurring in the large radius curve. The lateral force curving signature not only reveals the levels of lateral wheel-rail forces required for bogie curving, but also whether the bogie is curving by means of the creep forces generated at the wheel-rail interface only or if contact is necessitated between the wheel flange and rail gauge corner to help steer the bogie around the curve. The test set-up consisted of two free field microphones radially aligned at equivalent distances towards the in – and outside of the curve in line with a set a strain gauge bridges configured and calibrated to measure the lateral and vertical forces on the inner and outer rail of the curve. This test set-up allowed the squealing wheel to be identified from the magnitude difference of the sound pressures recorded by the inner and outer microphones in combination with comparing the point of frequency shift of the squeal event due to the Doppler Effect with the force signals of the radially aligned strain gauge bridges. From the experimental phase of the investigation, it was found that wheel squeal occurring in the 1000 m radius curve at Elands Bay is characteristic of empty wagons and is strongly related to the squealing wheel’s flange/flange throat being in contact with the gauge corner of the rail. Here high levels of spin creepage associated with high contact angles in the gauge corner lead to high levels of associated lateral creepage necessary for squeal generation. This is in contrast to lateral creepage due to high wheelset angles of attack being the key kinematic parameter influencing squeal generation in small radius curves. Furthermore, the amplitude of wheel squeal originating from the passing of empty wagons was found to be inversely proportional to the level of flange rubbing on the squealing wheel i.e. increased flange contact on the squealing wheel brings about a positive effect on squeal control. Contrary to the empty wagons which are characterised by tonal curve squeal, loaded 4 wagons requiring contact between the wheel flange and rail gauge corner in the 1000 m curve was characterised by broadband flanging noise. It was concluded from measurements that flange contact occurring under high lateral forces for steady state curving of loaded wagons provides the complete damping necessary for squeal control. The curve squeal noise that originated from the passing of empty wagons in the Elands Bay curve could further be classified according to the frequency at which the squeal event manifested itself in the curve, i.e. low frequency audible (0 – 10 kHz), high frequency audible (10 – 20 kHz) and ultrasonic squeal (> 20 kHz). The vast majority of low frequency audible squeal events recorded in the 1000 m Elands Bay curve occurred at approximately 4 kHz and originated from the low rail/trailing inner wheel interface, whilst the vast majority of high frequency audible squeal events occurred in the frequency range between 15 and 20 kHz and originated from both the high rail/leading outer wheel and low rail/trailing inner wheel interfaces.
24

Investigation into the application of semi-custom I.C. techniques to an advanced automotive multiplexed wiring harness

Poole, Philip John January 1987 (has links)
No description available.
25

The effect of the real world side impacts on occupant injuries : a finite element and statistical approach

Ashby, Darren January 2000 (has links)
No description available.
26

Modern Raman spectroscopy for investigation of host-pathogen interactions

Ochsenkühn, Michael Andreas January 2010 (has links)
Biomedical sciences are in need of more versatile and more sensitive approaches for research and also for diagnostic purposes. In particular, intracellular detection and imaging of disease relevant proteins is a challenge. Although the state of the art method of intracellular imaging is fluorescence, it suffers from several drawbacks. Raman is an alternative imaging modality and this work investigates the use of different Raman techniques for detection and imaging of cellular constituents. In one aspect of the work, surface-enhanced Raman spectroscopy using gold nanoshells excitable at a wavelength of 780 nm was investigated. Initially the investigation of the uptake of the 150 nm diameter nanoparticles showed that NS are taken up voluntarily by a non-standard en- docytosis mechanism into mammalian fibroblast cells. Furthermore it was shown that internalized particles have no detrimental in uence on cell growth or cell viability. That these nanoparticles are non toxic was further confirmed by testing for markers of apoptosis and necrosis. Preliminary surface-enhanced Raman spectroscopy (SERS) studies produced spectra from intracellular compartments with an enhancement factor of 1010. To yield high specificity of the intracellular Raman protein sensor, two different approaches were studied. The first is based on the application of DNA aptamers which form a stacked G-quadruplex on target protein binding. A SERS sensor based on the well characterized Thrombin binding aptamer (TBA) yielded high reproducibility, high target specificity, and a limit of detection down to 0.1 fM. Further studies on a similar stacked G-quadruplex forming aptamer confirmed that observed detection signal is produced by the aptamer assuming its secondary structure but also showed that the stabilization and formation of the G-quadruplex secondary structure is strongly buffer dependent. A second sensing approach was based on a peptide (a3(IV)NC1) influential in Goodpasture's syndrome, an autoimmune disease. With the help of this peptide we found that an intracellular redoxpotential of -200 mV is necessary to make it accessible for the protease Cathepsin D. We found that SERS sensing has the ability to study the binding of Cathepsin D, its activity and with the help of a synthesized amino-acid SERS library the direct detection of the remaining peptide products. Finally this work concludes with imaging the changes of lipid droplet structure and distribution in fibroblast cells during the infection process of the murine cytomegalovirus (MCMV) in fixed and in living cells by coherent anti-Stokes Raman based on a Synchro-lock phase coupled setup. This showed that CARS imaging is able to non-invasively investigate the changes of lipid structures during different stages of the infection process and therefore promises to be a valuable tool in biological research.
27

The Art Car Spectacle: a Cultural Display and Catalyst for Community

Stienecker, Dawn 08 1900 (has links)
This auto-ethnographic study focuses on Houston’s art car community and the grassroots movement’s 25 year relationship with the city through an art form that has created a sense of community. Art cars transform ordinary vehicles into personally conceived visions through spectacle, disrupting status quo messages of dominant culture regarding automobiles and norms of ownership and operation. An annual parade is an egalitarian space for display and performance, including art cars created by individuals who drive their personally modified vehicles every day, occasional entries by internationally renowned artists, and entries created by youth groups. A locally proactive public has created a movement has co-opted the cultural spectacle, creating a community of practice. I studied the events of the Orange Show Center for Visionary Art’s Art Car Weekend to give me insight into art and its value for people in this community. Sources of data included the creation of a participatory art car, journaling, field observation, and semi-structured interviews. The first part is my academic grounding, informed by critical pedagogy and socially reconstructive art practices. The second part narrates my experiences and understandings of the community along with the voices of others. Dominant themes of exploration include empowerment, community, and art. I examine the purposes for participation by artists, as well in the practices of audiences and organizations that provide support for this art form. My findings have significant implications community-based art education and k-12 classroom educators. Relational and dialogic approaches to making art, teaching, and researching are tied to problem-posing education as a recommendation for art education.
28

Lineare und nichtlineare Raman-Spektroskopie an biologisch relevanten Modellystemen / Linear and nonlinear Raman spectroscopy on biological relevant model systems

Schlücker, Sebastian January 2001 (has links) (PDF)
Im Rahmen dieser Dissertation wurden insgesamt drei verschiedene Fragestellungen an biologisch relevanten Modellsystemen mit Hilfe von diversen linearen und nichtlinearen Raman-spektroskopischen Techniken bearbeitet. Neben der Untersuchung von Wasserstoffbrücken-gebundenen Komplexen und ihrer Dynamik auf der fs-Zeitskala (Kapitel 4) bildeten Untersuchungen zur Struktur von Porphyrinen (Kapitel 5) und beta-Carotin (Kapitel 6) als Vertreter wichtiger Klassen von Biomolekülen den Schwerpunkt dieser Arbeit. Die spektroskopischen Ergebnisse wurden durchweg über Strukturen und Schwingungsspektren, welche mit Hilfe der Dichtefunktionaltheorie (DFT) berechnet wurden, unterstützt. Die dritte bearbeitete Thematik zum Nachweis anthropogener und ökologisch relevanter Aerosole war bioanalytisch motiviert und wurde anhand von Pestizid-Modellsubstanzen bearbeitet (Kapitel 7). / Three different problems on biological relevant model systems were investigated within the framework of this thesis by means of various linear and nonlinear Raman techniques. Besides the studies on hydrogen-bonded complexes and their dynamics on a fs-timescale (chapter 4), structural investigations on porphyrins (chapter 5) and beta-carotene (chapter 6) as representatives of important classes of biomolecules were the central subject of this dissertation. The experimental data were confirmed throughout by structures and vibrational spectra obtained from calculations based on density functional theory (DFT). The last topic, the detection of anthropogenic aerosols with ecological relevance, was motivated from bioanalytical chemistry. The corresponding investigations were carried out on pesticide model compounds (chapter 7).
29

Leverantörsrelaterade produktionsstörningar : en kvalitativ undersökning på Volvo Cars Uddevalla

Lundberg, Therese, Orvarson, Maja January 2004 (has links)
No description available.
30

Segmentation of the car market in China

Syed, Imran Ahmed, Saint, Adrien January 2013 (has links)
The Chinese car market has, through the last decade evolved into the major market in the world. Its car market from has become the world’s largest market from 2009 until today. With the emerging market that is China, the demand for cars is supposed to grow even more in the next decade.The thesis starts by studying the theories of consumer market segmentation with a hybrid and dynamic aspect. A quantitative investigation was conducted with the help of a survey. The survey was sent out to car consumers and potential car consumers who are residing in China. From this study the authors were able to anticipate possible preferential profiles.

Page generated in 0.0606 seconds