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  • 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.
51

Applying alternative fuels in place of hydrogen to the jet ignition process /

Toulson, Elisa. January 2008 (has links)
Thesis (Ph.D.)--University of Melbourne, Dept. of Mechanical Engineering, 2009. / Typescript. Includes bibliographical references (leaves 231-245)
52

A Threshold Coverage Flow-Refueling Location Model to Build a Critical Mass of Alternative-Fuel Stations

January 2015 (has links)
abstract: In order to address concerns about the dominance of petroleum-fueled vehicles, the transition to alternative-fueled counterparts is urgently needed. Top barriers preventing the widespread diffusion of alternative-fuel vehicles (AFV) are the limited range and the scarcity of refueling or recharging infrastructures in convenient locations. Researchers have been developing models for optimally locating refueling facilities for range-limited vehicles, and recently a strategy has emerged to cluster refueling stations to encourage consumers to purchase alternative-fuel vehicles by building a critical mass of stations. However, clustering approaches have not yet been developed based on flow-based demand. This study proposes a Threshold Coverage extension to the original Flow Refueling Location Model (FRLM). The new model optimally locates p refueling stations on a network so as to maximize the weighted number of origin zones whose refuelable outbound round trips exceed a given threshold, thus to build critical mass based on flow-based demand on the network. Unlike other clustering approaches, this model can explicitly ensure that flow demands “covered” in the model are refuelable considering the limited driving range of AFVs. Despite not explicitly including local intra-zonal trips, numerical experiments on a statewide highway network proved the effectiveness of the model in clustering stations based on inter-city flow volumes on the network. The model’s policy implementation will provide managerial insights for some key concerns of the industry, such as geographic equity vs. critical mass, from a new perspective. This project will serve as a step to support a more successful public transition to alternative-fuel vehicles. / Dissertation/Thesis / Masters Thesis Geography 2015
53

Drivers to and barriers against sustainable consumption : exploring the role of consumer anticipated emotions in the context of consumer adoption of alternative fuel vehicles

Rezvani, Zeinab January 2017 (has links)
With the increasing environmental problems, sustainable consumption is an important consumer behavior. Therefore, it is important to investigate further the significant drivers to and barriers against sustainable consumption, in order to increase the share of sustainable consumption and understanding of consumer behavior. This dissertation identifies two gaps. The first is in understanding consumer positive and negative anticipated emotions as an important factor influencing high-involvement sustainable consumption. The second gap relates to the lack of understanding about the associations between anticipated emotions and personal moral norms in high-involvement sustainable consumption. Against this background, the aim is to contribute to the sustainable consumption literature by investigating the roles and relations of anticipated emotions, personal moral norms, and weighing costs and benefits as drivers to and barriers against consumer adoption of a high-involvement sustainable product. A literature review and two empirical studies were conducted. Consumer adoption of alternative fuel vehicles is the specific sustainable consumption. Using quantitative methods, this phenomenon is investigated in the empirical studies conducted in Sweden. It was shown that anticipated emotions have direct effects on consumers' intention to adopt alternative fuel vehicles. Moreover, positive anticipated emotions (e.g. pride, pleasure, happiness) are drivers of sustainable consumption, while negative anticipated emotions (e.g. regret, embarrassment) are barriers against the sustainable consumption. This dissertation suggests an extension to the norm activation model, and shows that moral norms, ascription of responsibility, and awareness of environmental problems influence consumers' intentions through consumers’ anticipated emotions. For people who perceive high social norms related to decreasing the environmental impacts of car driving, the influence of positive anticipated emotions and personal moral norms are stronger. This points toward the social aspect of sustainable consumption and suggests that targeting the consumers who perceive high social norms is an important step to promoting sustainable consumption. Findings would be of relevance to marketers, policymakers and environmental organizations. Creating awareness and communicating personal responsibilities and moral norms related to the environment and consumption are important drivers for consumer adoption of sustainable products. However, it is noteworthy that consumer anticipated emotions about high-involvement sustainable products (such as alternative fuel vehicle) have also important influence on the sustainable consumption. Thus, consumer anticipated emotions should be considered in designing promotion programs.
54

Investigating end-user acceptance of autonomous electric buses to accelerate diffusion

Herrenkind, Bernd, Brendel, Alfred Benedikt, Nastjuk, Ilja, Greve, Maike, Kolbe, Lutz M. 08 September 2021 (has links)
To achieve the widespread diffusion of autonomous electric buses (AEBs) and thus harness their environmental potential, a broad acceptance of new technology-based mobility concepts must be fostered. Still, there remains little known about the factors determining their acceptance, especially in the combination of vehicles with alternative fuels and autonomous driving modes, as is the case with AEBs. In this study, we first conducted qualitative research to identify relevant factors influencing individual acceptance of autonomously driven electric buses. We then developed a comprehensive research model that was validated through a survey of 268 passengers of an AEB, operated in regular road traffic in Germany. The results indicate that a mix of individual factors, social impacts, and system characteristics determine an individual’s acceptance of AEBs. Notably, it is important that users perceive AEBs, not only as advantageous, but also trustworthy, enjoyable, and in a positive social light. Our research supplements the existing corpora by demonstrating the importance of individual acceptance and incorporating it to derive policy implications.
55

Developing Infrastructure to Promote Electric Mobility

Sandin, Carl-Oscar January 2010 (has links)
Electric mobility, E-mobility, will play a central role in a sustainable future transport system. The potential of curbing climate change in both short and long term are significant. Emobility will also offer the possibility to leapfrog the Internal Combustion car, IC-car, economy for developing countries. The low dependence of oil will be a benefit but E-mobility will demand a well functional electricity grid. Development of this grid will be beneficial for the developing world. For the European society E-mobility will in long term offer lower operating costs, decreased dependence of oil and lower emission of pollutants and Green House Gases, GHGs. All these factors are beneficial for the European society. The transition to E-mobility will depend upon a set of different factors and will call for different actions in order to overcome the barriers of E-mobility. A well developed charging infrastructure will be important in order to offer the full potential of E-mobility. The infrastructure will develop along with the market introduction of Electrical Vehicles, EVs. It is important that there are existing charging alternatives in the early introduction phase of EV in order to avoid the stagnation in the transition toward E-mobility. In order to provide the proper conditions for E-mobility, the determining factors must be investigated and evaluated. The four main factors are economical, social, R&D and infrastructure. The European driving patterns meet the offered operating range of an EV with ease. This means that EV has the potential to become an inner city vehicle under existing conditions. The investigation of the four determining factors leads to a base from which an implementation plan is suggested. The implementation plan is directed toward governments, energy utilities and other active participants in the development. The key factors of the implementation plan are to actively engage in the market, see E-mobility as a disruptive technology, use spin-off companies and social transparency. In order to gain the most from the implementation plan it is important that the correct actions are taken at the correct time. Therefore the transition period is divided into three phases; the introduction phase, the commercial phase and the re-development phase. The introduction phase will create the basic conditions for E-mobility. Government’s main action will be to invest in EVs and offer subsidies and other incentives to major companies that will equip their vehicle fleets with EVs. These actions will send signals toward vehicle Original Equipment Manufactures, OEMs, and other actors that the market of EVs is worth investing in. During the introduction phase try-out sessions, demonstrations and hearings will be important in order to communicate the advantages of E-mobility to society. Energy utilities will work to create roaming deals and standardization of important components and characteristics. The commercial phase is the most important phase for social adoption of E-mobility. During this phase commercial businesses will use EV charging a competitive advantage. New business models will be one of the keys to fully adoption of E-mobility. Cross industry alliances will reduce the initial cost, offer the service of a vehicle without owning it and leasing deals. The perception of travelling will shift and reduction of operating cost will be evaluated against travel time and planning. The re-development phase is based on a society that has adopted E-mobility. The development will proceed in order to offer more advantages to drivers but also to increase efficiency and to use the full potential of E-mobility.
56

Adoption of alternative fuel vehicles: Influence from neighbors, family and coworkers

Jansson, Johan, Pettersson, Thomas, Mannberg, Andrea, Brännlund, Runar, Lindgren, Urban 18 November 2020 (has links)
During the last years, many governments have set targets for increasing the share of biofuels in the transportation sector. Understanding consumer behavior is essential in designing policies that efficiently increase the uptake of cleaner technologies. In this paper we analyze adopters and non-adopters of alternative fuel vehicles (AFVs). We use diffusion of innovation theory and the established notion that the social system and interpersonal influence play important roles in adoption. Based on a nationwide database of car owners we analyze interpersonal influence on adoption from three social domains: neighbors, family and coworkers. The results point primarily at a neighbor effect in that AFV adoption is more likely if neighbors also have adopted. The results also point at significant effects of interpersonal influence from coworkers and family members but these effects weaken or disappear when income, education level, marriage, age, gender and green party votes are controlled for. The results extend the diffusion of innovation and AFV literature with empirical support for interpersonal influence based on objective data where response bias is not a factor. Implications for further research, environmental and transport policy, and practitioners are discussed.
57

Light Duty Natural Gas Engine Characterization

Hillstrom, David Roger January 2014 (has links)
No description available.
58

Effects of alternative jet fuels on aerospace-grade composites: experimental and modeling studies

Harich, Naoufal 12 May 2023 (has links) (PDF)
The aviation industry aims to reduce its environmental impact through innovation and research. The usage of composite materials for multiple primary structures represents one such measure. Several alternative fuels were approved and used along with the Federal Aviation Administration (FAA). These alternative fuels are produced from wastes and biomasses. Some alternative fuels were initially only approved as drop-in fuels, meaning they must be blended with conventional fuels to operate. Fuel tanks are usually embedded into the wing structure, which is mainly made of composite materials. These composites tend to absorb fluids it encounters through their matrix phase. The absorption behavior of conventional fuels by composite materials is well documented, while alternative fuels, blended or pure, are not as widely reported. The effects of four alternative fuel blends on aerospace-grade composites were investigated and compared with the conventional fuel Jet A. No significant differences were found in weight gain. The thermomechanical properties changes were also studied, with no difference between the alternative fuel blends and the conventional fuel. Additionally, model fluids with similar chemical structures as alternative fuels were used. The uptake of these model fluids was studied cyclically and compared with Jet A and one aromatic fluid. Small differences were seen in the weight gain results, primarily due to the type of model fluids used. Also, the thermomechanical properties showed no differences between these model fluids, Jet A and the pure aromatic fluid. This means that the slight differences in weight gain did not affect the changes in properties. From the results obtained, the alternative fuels blended, and the model fluids showed no differences in effects on the thermomechanical properties versus Jet A. This implies that similar effects are expected from either type of fluids used. Finite element analysis was used to model fluid’s diffusion in composite materials using different material parameters. The parameters were fiber packing, arrangement and permeability. Each parameters impacted the equilibrium uptake and the diffusion rate differently.
59

Modeling the traffic related pollution reduction through increased use of Hybrid-Electric Vehicles (HEVs) in Hamilton, Ontario, Canada

Kaneda, Naoya 04 1900 (has links)
<p>In this study, the effect of HEVs on traffic related pollution was assessed in the Hamilton CMA. This thesis aimed to combine findings from these two fields in a traffic simulation procedure. By introducing the HEVs in incremental levels to the vehicle travel pattern of more than 700,000 people in the study area, changes occurring in traffic related pollution at different levels were modeled.</p> <p>The hypothetical HEV spatial distribution patterns models were derived through negative binomial regression modeling based on 2006 census data and 2008 vehicle registration data. The distribution of predetermined number of HEVs throughout the Hamilton CMA was completed through these models and results were used to modify input OD matrices for the TRAFFIC program. The link-based emissions were calculated in combination with traffic emission factors for HEV.</p> <p>The results indicated that converting 10% of the total fleet into HEVs was needed to make significant reductions to the HC and CO aggregate emissions in all five models. An important finding with the incremental HEV penetration levels was the approximately linear trend between the percent reduction in the traffic emissions and the percent of HEVs in the total fleet. This trend allows calculations of approximate traffic emission reduction expected with any HEV level. The results illustrating links with more than 10% reduction in traffic emissions indicated that HEV technology as an effective method in dealing with environmental concerns.</p> / Master of Arts (MA)
60

Shock Tube Ignition Studies of Renewable Diesel Fuels for Medium and Heavy-Duty Transportation

Mohammed, Zuhayr Pasha 01 January 2024 (has links) (PDF)
Currently extensive research on alternative fuels is being conducted due to their increasing demand to reduce greenhouse emissions. One renewable fuel studied in this work is dimethyl ether (DME) blended with propane(C3H8) as a potential mixture for heavy-duty engines used in semi-trucks. The blend has the potential to drastically reduce particulate and greenhouse gas emissions compared to a conventional diesel engine operating under similar conditions. To develop the use of mixture, one must conduct detailed conceptual and simulation studies before progressing to detail studies in CFD, engine modifications, and live testing. For simulations, accurate high-fidelity chemical kinetic models are necessary. However, the validity of the chemical kinetic mechanism for operating conditions of a heavy-duty mixing-controlled compression (MCCI) engine was widely unknown until recent work presented here and published. In this work, we studied the ignition of DME and propane blends in a shock tube under MCCI engine conditions. Ignition delay time (IDT) gathered behind the reflected shock for DME-propane mixtures for heavy-duty compression ignition (CI) engine parameters. Testing was conducted for undiluted varieties spanning from temperatures of 700 to 1100 K at pressures ranging from 55 to 84 bar for various blends (100% CH3OCH3, 100% C3H8, 60% CH3OCH3/ 40% C3H8) of DME and propane were combusted in synthetic air (21% O2/ 79% N2). Several experiments were conducted at higher pressures (90-120 bar) to improve the model performance and accuracy. The ignition delay times (IDTs) were compared to recent mechanisms, including Aramco3.0, NUIG, and Dames et al. A common trend among the mechanisms was overpredicted experimental IDTs. Further studies were conducted by a sensitivity analysis using the Dames et al. model, and critical reactions sensitive to IDTs of DME-propane mixture near 60 bar are outlined. Chemical analysis was conducted on the NTC region to explain chemical kinetics which is critical for developing MCCI heavy duty engines.

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