• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 192
  • 45
  • 17
  • 11
  • 9
  • 5
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 330
  • 82
  • 37
  • 29
  • 29
  • 29
  • 28
  • 27
  • 26
  • 26
  • 26
  • 25
  • 24
  • 22
  • 22
  • 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.
141

The environmental impact assessment of manual and automatic truck types

Maithani, Abhinav January 2020 (has links)
Trucks are used to transport goods and services using road transportation. Emissions from the transportation industry are rising with every passing year. The Swedish government said in a report in 2009 that they are working to reduce 70% of the greenhouse gas emissions by 2030 to build a pathway for sustainable transportation (Allerup, 2019). New technologies in the field of transportation are coming to the market every year. It is important to evaluate the impacts from these technologies to support the 2030 agenda of Swedish government. Life cycle analysis of trucks can give valuable insight into the hotspots from different life cycle stages. To provide a comprehensive overview of the emissions from different types of heavy duty trucks namely Internal combustion engine trucks (Manual and driverless) and electric trucks (manual and driverless) a life cycle assessment is carried out.  From the comprehensive evaluation of results, following questions are answered. [1] Global warming potential from different types of heavy duty trucks; [2] Impacts from the new automation technology on climate change; [3] Environmental hotspots evaluation of the different truck types; and [4] Impacts of using different fuel types on the Global warming potential. Overall, the life cycle assessment can help the decision makers for taking decisions in order to fulfill the agenda 2030 of the Swedish government but still further research is needed to be done to exactly find out the emissions level of new automation technologies. / Lastbilar används för att transportera varor och tjänster med vägtransport. Utsläppen från transportbranschen ökar för varje år som går. Den svenska regeringen sa i en rapport 2009 att de arbetar för att minska 70% av växthusgasutsläppen till 2030 för att bygga en väg för hållbara transporter. Ny teknik inom transportområdet kommer till marknaden varje år. Det är viktigt att utvärdera effekterna av denna teknik för att stödja 2030-agendan för den svenska regeringen. Livscykelanalys av lastbilar kan ge värdefull inblick i hotspots från olika livscykelsteg. För att ge en omfattande översikt över utsläppen från olika typer av tunga lastbilar, nämligen IC-motor bilar (manuella och förarlösa) och elektriska lastbilar (manuella och förarlösa) genomförs en livscykelbedömning.  Från den omfattande utvärderingen av resultaten besvaras följande frågor. [1] Global uppvärmningspotential från olika typer av tunga lastbilar; [2] Effekter från den nya automatiseringstekniker på klimatförändringar. [3] Miljö Hotspots utvärdering av olika lastbilstyper; och [4] Effekter av användning av olika bränsletyper på den globala uppvärmning potentialen. Sammantaget kan livscykelbedömningen hjälpa beslutsfattarna att fatta beslut för att uppfylla den svenska regeringens dagordning 2030, men ytterligare forskning behövs för att exakt ta reda på utsläppsnivån för ny automatiseringsteknik.  Resultaten av studien visar att elbilen har lägre GWP-utsläpp än IC-motor bilarna. Den förarlösa automatiseringstekniker har 1,37% av de totala GWP-utsläppen när det gäller IC-motor bilar. Medan för elektriska lastbilar bidrar förarlös automatiseringsteknik upp till 12% av de totala utsläppen av elbil.
142

Hijacking of trucks with freight : a criminological analysis

Buys, Johannes Jacobus 11 1900 (has links)
A considerable amount of research has been done regarding the hijacking of passenger vehicles. Little however, has been written on the hijacking of trucks with freight. The purpose of the research was to describe the nature, occurrence and extent of the hijacking of trucks with freight, the persons involved (this includes the victims and the offenders) and the impact these crimes have on the crime scene in South Africa. The research also aimed to develop a criminological model for prevention, based on the modus operandi of the offenders. Based on the theories explaining violent and economic crimes (e.g. anomie, differential association and sub-culture), an attempt was also made to explain the hijacking of trucks with freight. / Criminology / M.A.
143

Hijacking of trucks with freight : a criminological analysis

Buys, Johannes Jacobus 11 1900 (has links)
A considerable amount of research has been done regarding the hijacking of passenger vehicles. Little however, has been written on the hijacking of trucks with freight. The purpose of the research was to describe the nature, occurrence and extent of the hijacking of trucks with freight, the persons involved (this includes the victims and the offenders) and the impact these crimes have on the crime scene in South Africa. The research also aimed to develop a criminological model for prevention, based on the modus operandi of the offenders. Based on the theories explaining violent and economic crimes (e.g. anomie, differential association and sub-culture), an attempt was also made to explain the hijacking of trucks with freight. / Criminology and Security Science / M.A.
144

Autonoma och elektrifierade lastbilstransporter : Hållbara transportlösningar genom framtidsscenarier / Autonomous and electrified freight trucks : Sustainable transport solutions through future scenarios

Östling, Felicia, Blomkvist, Alva January 2023 (has links)
The aim of the thesis was to deepen the knowledge of sustainability aspects in the field of transportation for the ongoing digital development of autonomous and electrical freight trucks toward the year 2030 in the Swedish context. To achieve the above aim, three objectives were formulated. The first objective was to identify critical factors for the envisioned digital and electrical development, the second objective was to create and design three future scenarios for the year 2030, and the final objective was to apply the scenarios to several stakeholders. The critical factors were identified via the analysis of conducted interviews with several stakeholders. Based on these findings, three scenarios were created, which then were evaluated by several focusgroup interviews and ordinary interviews conducted with additional relevant stakeholders. In the evaluation, radar charts were used to clarify the stakeholders’ views and to assess different factors within each and every scenario. The factors that were evaluated with the radar charts were the drivers' situation, cooperation, investments, competitiveness, capacity, and energy consumption. The obtained results show that all three sustainability aspects have a significant impact on the future and envisioned development of the transportation industry. The outcomes of these objectives were then synthesized into relevant aspects and some formulated recommendations focusing on their role and relevance from a sustainability perspective. The list of recommendations is addressed to Trafikverket, providing the authority with future directions for advancing the ongoing development of autonomous and electric freight trucks. To conclude, the results from the thesis can assist stakeholders to increase sustainability and public welfare in the further development of autonomous and electric freight trucks in Sweden.
145

Design, development and testing of a 2-DOF articulated dump truck suspension seat

Barnard, Charl 03 1900 (has links)
MScEng / This project entails the design and development of a new 2-DOF articulated dump truck (ADT) suspension seat. A study of the ADT vibration environment was conducted using data measured with accelerometers inside the cabin. With the system’s required operational capabilities determined, the concept design phase resulted in a feasible concept. The first prototype was manufactured based on the initial set of specifications. A variety of numerical modelling techniques were used to analyse and evaluate the seat’s dynamic response. Vertical and lateral laboratory tests of the suspension seat with human occupants were completed. The vertical lumped parameter model of the suspension seat with a human occupant gave good correlation with the laboratory measured frequency response. A broad band input signal, and not the ISO 7096 (2000) EM1 signal, was used to obtain the frequency response used to verify the lumped parameter model. The SEAT values for the ISO 7096 (2000) EM1 signal and various ADT road conditions were calculated using the lumped parameter models for a small, medium and large subject, the same three subjects used in the laboratory tests. SEAT values using the ISO 7096 (2000) EM1 signal of 0.94, 0.93 and 0.88 were obtained for the small, medium and large subjects. The lowest SEAT values obtained using the road data were 0.63, 0.56 and 0.48 for the small, medium and large subjects. The transmissibility curves determined from the lateral laboratory tests were used to calculate the SEAT values for the lateral ADT cabin vibrations. The lowest SEAT values obtained were 0.83, 0.83 and 0.82 obtained for the small, medium and large subjects. After all the results from the testing and modelling were evaluated the design was assessed. All the data and information collected was used as input for the design of a second prototype, which was not manufactured. Not all the set specifications were achieved for the first prototype, but the new suspension seat gave comparable vertical vibration isolation performance to that of expensive commercially available ADT suspension seats. The lateral suspension demonstrated good lateral vibration isolation and is a feature not currently available in current ADT suspension seats.
146

Reducing the total cost of ownership of mining haul trucks

Riley, Lennard Barry 12 1900 (has links)
Thesis (MScIngwet)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The diesel consumption of haul trucks deployed on opencast mines was investigated as a means of reducing the Total Cost of Ownership (TCO) of mining haul trucks. The conceptualisation of TCO and an introduction to the mining operation was presented as an introduction to the field of research. Thereafter, a review of the available literature revealed that linear programming, queueing theory and coast-down testing were applicable means of investigation. The relevant engineering sciences were applied and correlated with experimental and measured data from the Grootegeluk, Sishen and Thabazimbi mines operated by Kumba Resources Ltd (formerly known as ISCOR Mining). A cost-driver model for diesel consumption was formulated by exploiting the expert judgement of role players in the mining operation. A cost-driver model was developed for the Sishen, Thabazimbi and Grootegeluk mines. The cost-driver models were then modelled as a linear programming problem and solved using the student version of LINDO Optimization Software. The results were discussed and a universal diesel cost driver model was formulated by consolidating the individual diesel cost driver models. The operational cycle of haul trucks was simulated in order to quantify equipment utilisation and reduce diesel consumption of the mining vehicles. The operational cycle of haul trucks was modelled utilising queueing theory. The simulation of the queue network was implemented in Matlab using the next event advance method and was called Q Sim. Q Sim - - was utilised to investigate optimal fleet size and the economies of scale of haul truck capacity. The results of coast down tests were analysed in order to determine the effect of treating mining roads, with a bitumen product, on rolling resistance coefficient. Finally, recommendations for further research are proposed. This includes further refinement of the diesel cost-driver model, expanding the scope of application of Q_Sim in the mining operation and further investigation of dust reduction by bitumen products. / AFRIKAANSE OPSOMMING: Ondersoek is ingestel na die dieselverbruik van myntrokke sodoende die Totale Koste van Eienaarskap (TKE) van myntrokke te verminder. Die konsep rondom TKE is bespreek en 'n inleiding tot die mynybedryf is aangebied sodoende die verskeie aspekte in verb and te bring. 'n Literatuur studie het gevolg, wat aangetoon het dat lineere programmeering, toustaan-en loswieltoetse toepaslike navorsingsmetodes is om die nodige resultate te verkry. Daarna is hierdie ingenieurswetenskappe toegepas en 'n vergelyking is tussen die eksperimentele en gemete data van die Grootegeluk, Sishen en Thabazimbi myne getref. 'n Diesel koste-drywer model is opgestel met die insette van kundige rolspelers in die mynbou bedryf. Dit het gelei tot Koste-drywer modelle vir die Sishen, Thabazimbi en Grootegeluk myne. Die modelle is met lineere programmeering as probleemstelling daargestel en is deur middel van die studente weergawe van die LINDO optimaliseringssagteware opgelos. Die resultate was toe bespreek en daarvolgens is 'n universele diesel koste-drywer model opgestel deur die reeds-geskepte modelle te konsolideer. Die operasionele siklus van myntrokke was gesimuleer sodoende die benutting van toerusting te kwantifiseer en die dieselverbruik van myntrokke te verminder. Hierdie operasionele siklus was gemodelleer deur middel van die toustaan-teorie. Die simulasie van 'n toustaannetwerk was in Matlab gevoer deur Q_Sim te gebruik. Hierdie metode was gebruik om die optimale vloot grootte en die invloed van myntrokkapasiteit te ondersoek. Die ontleding van die loswieltoetse was gedoen om die invloed van In bitumen prod uk op rolweerstand te bepaal. Ten slotte is aanbevelings vir toekomstige navorsing bespreek. Dit behels die verder aansuiwerings van die diesel koste-drywer model, die uitbreiding van aanwending van die Q_Sim in die mynbou en 'n verdere ondersoek om stofvoorkoming in die mynbou te bewerkstellig deur die gebruikmaking van bitumen produkte.
147

The use of seating systems to reduce whole body vibration exposure in the SA industry

Gunaselvam, A. J. M. (Ariyamalar Jessica Miriam) 12 1900 (has links)
Thesis (MScEng)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The purpose of this study was to investigate the specification and use of appropriate seating systems to reduce whole-body vibration exposure in typical vehicles used in South African industry. As part of this study six suspension seats, which the manufacturers claim satisfy the requirements in ISO 7096 (2000), were tested. Six test subjects, three light and three heavy as specified in ISO 7096, were used to estimate the seat transmissibility functions in the vertical direction of the six different suspension seats. Transmissibility functions were measured in the laboratory using two excitation levels, 1m/s2 and 2 m/s2 r.m.s., of broadband frequency vibration and a spectrum approximating the EM5 spectral class in ISO 7096. SEA T values were calculated for operational vibration data measured in an articulated dump truck and a three-wheeled logger. It was shown that SEAT values for the EM1 spectral class could not be reliably estimated from seat transmissibility functions and need to be measured directly in the time-domain. The measurement procedures and seat selection criteria developed in this research project were used to compile a set of "Design Guidelines for Seat Selection for Whole-Body Vibration Control in Industrial Vehicles". These guidelines will provide manufacturers with an easy-to-implement methodology to control whole-body vibration transmitted to the operators of industrial vehicles and to comply with international regulations for whole-body vibration transmission. / AFRIKAANSE OPSOMMING: Die doel van die studie was om die spesifikasies en gebruike van geskikte sitplek stelsels van uit Suid Afrikaanse industriële voertuie, wat heel-liggaam vibrasies verminder, te ondersoek. Ses suspensiesitplekke, wat deur die vervaardigers voorgeskryf word, is getoets om te sien of hulle aan die ISO 7096 (2000) vereistes voldoen. Ses persone, waarvan drie lig en drie swaar is, soos in ISO 7096 voorgeskryf, is gebruik om die sitplek oordragsfunksies in die vertikale rigting vir die ses verskillende suspensiesitplekke te skat. Die oordragsfunksies is in die laboratorium gemeet deur twee opwekkingsvlakke, 1m/s2 en 2m/s2 w.g.k., van wyeband frekwensie vibrasie en n spektrum beraam tot die EMS spektrum soos in ISO 7096. 'SEA T' waardes was vanaf operationele vibrasie data wat in ge-artikuleerde vragmotors en driewiel- 'loggers' gemeet is bereken. Daar is gewys dat betroubare 'SEAT waardes vir die EM1 spektrum nie van sitplek oordragsfunksies geskat kan word nie, maar dat dit eerder direk van die tyd-gebied afgelees moet word. Die metings prosedures en die sitplek keuse vereistes wat in die navorsingsprojek ontwikkel is, is gebruik om "Ontwerp Riglyne vir Sitplek Keuse Vereistes vir Heel- Liggaam Vibrasie in Industriële Voertuie" saam te stel. Hierdie riglyne sal vervaardigers met maklik toepasbare metodes toerus om heel-liggaam vibrasie, wat oorgedra word na industriële voertuig operateurs, te beheer en om aan internasionale regulasies t.o.v. heel-liggaam vibrasie oordrag te kan voldoen.
148

An AIS-based vehicle control framework in port container terminals

Lee, Man-ying, Nicole, 李文英 January 2008 (has links)
published_or_final_version / Industrial and Manufacturing Systems Engineering / Master / Master of Philosophy
149

The application of environmental requirements in procurement of road maintenance in Sweden

Faith-Ell, Charlotta January 2005 (has links)
<p>The Swedish Road Administration (SRA) is responsible for maintenance of the state-run roads in Sweden. The SRA also has an overarching responsibility for the state of the environment in the road transport sector. The overall aim of this thesis is to examine the implementation of environmental requirements in SRA road maintenance contracts and to develop an improved model for the implementation of environmental requirements, making it easier for the SRA to establish an optimal contracting strategy for routine road maintenance. Using several qualitative methodologies, the thesis is mainly based on a content analysis of 18 tender documents, two case studies consisting of five cases and a questionnaire. The study shows that the SRA have stipulated environmental requirements in procurements of routine road maintenance since 1997. The formulation of the environmental requirements was initially carried out at the Regional Road Management Directorates. However, in the case of trucks and construction vehicles relevant organisations were given the opportunity to actively participate in the development of environmental requirements. The contractors in the study fulfil about three-quarters of the environmental requirements in the contracts. The main reasons for not complying with the environmental requirements are: i) absence of consultation with municipalities and competent authorities, and ii) inadequate communication of environmental requirements to subcontractors. The benefit to the environment of laying down environmental requirements for road maintenance is difficult to assess, due to unclear environmental requirements and the fact that the SRA does not systematically follow up the environmental requirements. The findings of the research indicate that the SRA have made a serious effort to integrate environmental aspects in their maintenance contracts through the use of environmental requirements. However, the SRA need to adopt a more systematic approach towards road maintenance contracts in order to make green procurement an effective tool for environmental adaptation of road maintenance. The thesis proposes an improved process for development, implementation and follow-up of environmental requirements. The proposed process can be summarised in five criteria that need to be fulfilled in order to achieve an environmentally efficient application of environmental requirements: i) the environmental requirements have to be based on legislation, environmental quality objectives, identified environmental problems and/or research, ii) environmental indicators and baselines have to be established in order to facilitate follow-up of compliance with the requirements, iii) the environmental requirements have to be stated clearly in order to limit misinterpretations and to facilitate follow-up, iv) the contractors have to develop working processes, routines and training based on the environmental requirements, v) routines for following-up compliance with the requirements and the environmental effectiveness need to be developed, and there has to be a feedback of the results. Furthermore, the purchasing function needs to be integrated with the implementation of the contracts. Although, having faced several problems during the introduction of environmental requirements, the SRA have managed to meet the main arguments that are used for justification of green procurement. However, if slightly changed, the process of green procurement has the potential of becoming an important tool in the work for enhancing the environmental performance of the SRA.</p>
150

//Fluxspace: temporary acts as social catalysts in Kansas City / Flux space

Wagner, Benjamin N. January 1900 (has links)
Master of Landscape Architecture / Department of Landscape Architecture and Regional & Community Planning / Jessica Canfield / Kansas City is in the midst of an urban renaissance, with a construction boom within the downtown core in excess of $4.5 billion over the past several years (CVA 2012). In 2010, Kansas City’s Greater Downtown Area Plan (GDAP) was implemented to guide the future transformation and development of the city. Despite its long-term vision and specific goals, including activating the public realm and fostering a strong urban community (City Planning et al. 2010), the GDAP fails to address opportunities for short-term strategies for interim ‘place-making.’ Yet, temporary gatherings are critical to fostering and sustaining a sense of ‘place.’ Kansas City currently has an emerging, vibrant urban culture, but it lacks amenities and spaces to support and celebrate spontaneous social activity. To address this issue, this project proposes a series of prototypical fluxspaces – small, temporary interventions activated by the presence of food trucks - throughout Kansas City’s downtown area. These new temporary acts exploit the potential of underutilized urban surfaces in the short term while re-invigorating social activity and celebrating an emerging urban culture in the long term. Sites are linked to existing mobile food vending hot spots and interventions are timed in conjunction with major Kansas City events and festivals; this grounds the proposed system in Kansas City’s population of temporary users. A detailed schedule ensures that Kansas City’s fluxspaces feature a dynamic, rotating population of food trucks, while fluctuating amenities promote diverse, exciting, and attractive temporary places. Kansas City’s new fluxspaces accommodate spontaneous social gatherings and celebrate their vital importance in fostering a vibrant urban environment. //fluxspace activates Kansas City’s latent urban surfaces, filling the gap between Kansas City’s immediate need for places of temporary gathering and the long-term goals inherent in the vision for Kansas City’s future.

Page generated in 0.0557 seconds