• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 70
  • 11
  • 4
  • 3
  • 2
  • 1
  • 1
  • Tagged with
  • 110
  • 24
  • 19
  • 18
  • 14
  • 11
  • 10
  • 9
  • 9
  • 9
  • 9
  • 9
  • 8
  • 8
  • 8
  • 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.
61

Účetnictví podniku zabývajícího se kamionovou dopravou / Accounting firm dealing with truck traffic

Fockeová, Eva January 2011 (has links)
In my work I focus on accounting firms engaged in road transport. The aim of my work is to capture and describe the accountin practices in this area of business. the first section describes the general legal and economic conditions for the company to do business in this area. The main part is devoted to the actual accounting practices mainly illustrated by concrete examples of specific companies, as well as procedures for the proper preparation of the financial statements. At the end of the financial analysis attached statements.
62

Autonomous Landing on Moving Platforms

Mendoza Chavez, Gilberto 08 1900 (has links)
This thesis investigates autonomous landing of a micro air vehicle (MAV) on a nonstationary ground platform. Unmanned aerial vehicles (UAVs) and micro air vehicles (MAVs) are becoming every day more ubiquitous. Nonetheless, many applications still require specialized human pilots or supervisors. Current research is focusing on augmenting the scope of tasks that these vehicles are able to accomplish autonomously. Precise autonomous landing on moving platforms is essential for self-deployment and recovery of MAVs, but it remains a challenging task for both autonomous and piloted vehicles. Model Predictive Control (MPC) is a widely used and effective scheme to control constrained systems. One of its variants, output-feedback tube-based MPC, ensures robust stability for systems with bounded disturbances under system state reconstruction. This thesis proposes a MAV control strategy based on this variant of MPC to perform rapid and precise autonomous landing on moving targets whose nominal (uncommitted) trajectory and velocity are slowly varying. The proposed approach is demonstrated on an experimental setup.
63

Evaluation of two different mechanized earth moving technologies truck and shovel and IPCC for handling material from a large open pit mine using requesite design and operational conditions, efficiency, cost , skills and safety as criteria using sishen iron ore mine as a case study

Banda, Nelson January 2016 (has links)
An advanced coursework and a project submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements of MSc. Engineering (Mining), November 2015 / General For mining operations, both underground and open cast, there are generally accepted criteria used to arrive at the optimum mining method with which to exploit the ore body economically. Having selected the optimum mining method, mining companies should then make the decision to also select the optimum technology to apply given the various options that are now available. In the case of a shallow massive ore body where open-pit mining has been selected as the optimum mining method, the use of conventional trucks and shovels has been the popular choice but over the years, as pit become deeper, and stripping ratios increase, growing interest and adoption of in-pit crushing and conveying for both ore and waste has been gaining ground with several mining sites currently now operating, testing the systems or conducting studies at various stages for In-pit Crushing and Conveying (IPCC) in its different configurations (Chadwick, 2010). Open pit mining general involves the movement of pre-blasted or loose waste ahead of underlying ore out of the pit or to a previously mined part of the pit. This is then followed by the drilling and blasting or loosening of the ore and transportation to the processing plant or stockpiles. The conventional Truck and Shovel open pit operation involves the use of shovels – electric rope shovels, diesel or electric hydraulic shovels or excavators or front-end loaders to load the blasted, or loose waste and ore material in the pit onto mining trucks which haul the material to crushers or stockpiles if it is ore or to waste dumps in the case of waste. In a Fully Mobile IPCC (FMIPCC) system, the broken or loose material in the pit is loaded into a crusher or sizer by a shovel, continuous miner or dozer, crushed to a manageable size and transported by conveyor belts to the waste dump where it is deposited in place using spreaders if it is waste or onto stockpiles if it is ore. A combination of the two systems is where trucks dump material loaded at the face into a semi mobile crusher or sizer located in the pit close to the loading points N BANDA 392438 before conveying to destination thereby reducing truck haulage distance. In the semi-mobile configuration, the crusher is relocated closer to the loading points to minimise the hauling distance. Other various configurations are also employed depending on the various considerations. Although the Truck and Shovel system is considered as the convention in open pit mining, the IPCC system is not a new concept and has been operational on a number of mines worldwide for quite a number of years (Szalanski, 2010). Loading and hauling receive great attention especially in a high volume open pit mines due to the high cost contribution to the overall operation and therefore, if optimised, good cost savings can be realised (Lamb, 2010). Figure 1: Sishen Mining Cost Breakdown In the case of Sishen Loading and Hauling costs constituted 67% of the mining costs including labour mining support services in 2013 (Kumba Iron Ore, 2013). This picture remains unchanged to a large extent. In some cases the hauling cost alone can make up as much as 60% of the mining operating cost (Meredith May, 2012) Selection of a materials handling system between Truck and Shovel (T/S) and In-pit Crushing and Conveying (IPCC) has proven to be difficult due to limited understanding of the IPCC system especially its advantages and disadvantages relative to the Truck and Shovel system. The aim of this research was to unpack these two systems in terms of their applicability using studies conducted at Sishen 6,5% 8,8% 29,1% 22,7% 9,7% 0,6% 1,3% 0,4% 7,0% 4,2% 3,7% 5,9% Sishen Mining Cost 2013 Blasting Drilling Hauling L&H Contractors Loading Maintenance Other Mining Manangement Mining Engineering Mining Other Resource Management SHEQ Mining Support N BANDA 392438 Mine as well as develop some scorecard that could be used to select one over the other one. Sishen Case Study Sishen Mine is an iron ore open pit mine located in the Northern Cape province of South Africa and is part of Kumba Iron Ore Company which is Anglo American PLC. The mine has been in operation since 1953 with the current life of mine going up to 2030. It produces 44Mt tonnes of product from a 56Mt mine ore at a life of mine strip ratio of 4. One of the planned expansion the north part of the mine known as the GR80 and GR50 areas. Mining in these areas will require pre-stripping of 290Mt of clay material over the life of mine to expose the ore in pre volume phases. Figure2: Sishen Pit –Sishen Mine 2014. Sishen mine is constantly evaluating various technologies in its mining operations aimed at improving its bottom line by way of increasing productivity and efficiency, reducing costs and improving safety, however, the last time that the mine considered evaluating a technology that significantly could have resulted in a totally different operational philosophy was i contracted to institute a study to evaluate technology options for mining and moving majority owned by a minimum of 437Mt of calcrete and the underlying pre- g in 2007 when Snowden Mining Consultants run-ofmine areas is in -planned time and were N BANDA 392438 55 Mt of the calcrete/clay material per year from the waste pushback area in the GR80/GR50 area of the mine from 2009 till 2030. Snowden completed the Prefeasibility study in early 2008 in which they evaluated a conventional Truck and Shovel operation as well as IPCC. Economic viability of both systems in various configurations was demonstrated with the use of larger trucks and shovels ranked as the most economic option in terms of Net Present Cost (NPC), unit owning and operating cost per mined tonne and, to a less extent, in terms of risk and other considerations. In this case, the Truck and Shovel option was more economic than both IPCC configurations. However the small difference in the cost figures gave rise to interest in further evaluations. Following the Snowden study, Sishen engaged Sandvik Mining and Construction in 2008, to review the work done by Snowden and provide more detail and practical input to the IPCC system at scoping level. In the review, the IPCC system was shown to be the economic approach for the waste removal from the target area in terms of owning and operating cost. Practicality was also demonstrated and the case for the consideration of the IPCC system was put forward to Sishen. A further consultant, Sinclair Knight Merz (SKM) of Australia, was engaged, in the later part of 2008, to further evaluate and optimise the IPCC option to further demonstrate practically in detail at a feasible study level and strengthen its case by mitigating perceived risk. This included equipment specifications, mine and equipment layout per period per bench and risk assessment on the IPCC options. The mine, however, implemented the conventional truck and shovel option using larger equipment. The final decision was to stick with the current set up of Truck and Shovel system and gradually replace the current fleet of 730E Komatsu (190 tonne payload) trucks with the 930E or equivalent ( 320 tonne payload) and the current XPB 2300 P& H electric rope shovels and CAT 994/Komatsu WA1200 front end loaders with XPC 4100 P&H electric rope shovels, Komatsu PC8000/Liebherr 996 diesel hydraulic shovels and LeTournea L-2350 front end loaders to reduce the number of equipment and manage the operational cost. This decision was based on issues around initial capital investment, flexibility of the system to suit changing mining plans, ability of current personnel to run the system and general low risk appetite for change. The adopted option has its own challenges N BANDA 392438 such as supporting infrastructure requirements, labour intensity and associated low productivity and high cost, fleet management challenges to achieve required productivity constantly, supplies such as fuel and tyres and safety issues due to traffic density. A high level recalculation of the costs using current information was done as part of this research. For simplicity, no escalations or discounting were applied on future expenditure. The estimated unit owning and operating costs in 2014 terms for the study area were as follows:- Fully Mobile IPCC (FMIPCC) option ZAR 10.38/t, Semi Mobile IPCC (SMIPCC) option ZAR 13.12/t, Truck and Shovel option ZAR 15.80/t. The objective of this research is to use lessons from the Sishen case as well as other operations and gather expert views with the aim of establishing criteria that could be applied in a preliminary evaluation that would determine the suitability of either of the materials handling options. General Approach The costs were recalculated using as much current information as possible. Other considerations including advantages and disadvantages of either of the systems were examined in more detail, with real life examples examined where possible. This resulted in the establishment of generalized criteria for the selection of mining and transport technology for a large open pit mine with focus on conventional Truck and Shovel systems on one hand and IPCC systems, in their various formats, on the other. These criteria which identify conditions necessary for the successful adoption and implementation of either of the systems could then be used as input into the decision to carry out any further detailed studies of the options. The previous study reports on the Sishen mine case were examined, input parameters to the calculations checked and the general approached analyzed for practicality. The relative costs were also viewed for comparative purposes. Literature on these two main systems was reviewed including that from conferences. Other large operations running either one or both systems were looked at to gain N BANDA 392438 further insight. Original Equipment suppliers’ views on these systems were also looked at through many articles in the public domain. Sishen mine has previously had the IPCC system running in the same part of the mine in a semi mobile configuration, crushing and conveying waste. It was then changed to become a supplementary system for the ore handling system and the in pit crusher has never been relocated. The Truck and Shovel system took over the movement of all the waste and most of the ore at the mine. Lessons from these experiences were incorporated in this study.
64

The effect of outsourcing and situational characteristics on physical distribution transportation efficiency

Bienstock, Carol C. 06 June 2008 (has links)
This research examined the outsourcing decision for the logistics function of motor carrier transportation. A full factorial design was executed on a simulated transportation network to investigate how the efficiency of motor carrier transportation was affected by how it was structured (private/leased fleet versus contract carrier transportation) and the characteristics of the transportation activities. Transaction Cost Analysis (TCA) offered a useful theoretical framework for consideration of this make or buy decision by suggesting the independent variables of asset specificity, uncertainty, and frequency/volume. Seven two-part research hypotheses examined the relationships among the independent variables to gain a greater understanding of the factors which drive the make versus buy decision for motor carrier transportation. The major conclusions of this research are: 1) For the system modelled here, structure (private/leased versus contract carriers) and volume had the largest effects on transportation efficiency (mean shipment cost). 2) The results of this study indicated that there may be important factors within the nature of the “supplying” industry that impact the make or buy decision. This research provided strong support for TCA predictions and clearly demonstrated that TCA is a useful framework for understanding firms’ make or buy decisions. Because of the nature of the transportation industry (the high level of competition and the lack of a small numbers bargaining situation), the hypotheses in this research clearly indicated that a "buy" rather than a "make" decision was the most efficient alternative; this result is exactly consistent with TCA predictions. 3) For the system modelled here, higher fixed and per mile equipment leasing expenses (incurred in the operation of refrigerated trailers) caused refrigerated shipments to be more expensive than standard dry trailer shipments. That is, asset specificity (in this case, requirements for refrigerated trailer equipment) had a significant effect on shipment efficiency. / Ph. D.
65

Le rôle du transport industriel dans l'organisation des territoires régionaux : le cas des produits métalliques au Saguenay--Lac-Saint-Jean--Chibougamau /

Dion, Martin, January 2006 (has links)
Thèse (M.E.I.R.) -- Université du Québec à Chicoutimi, 2006. / La p. de t. porte en outre: Mémoire présenté à l'Université du Québec à Chicoutimi comme exigence partielle de la maîtrise en études et interventions régionales. CaQCU Bibliogr.: f. [124]-129. Document électronique également accessible en format PDF. CaQCU
66

Decreasing the cost of hauling timber through increased payload

Beardsell, Michael G. January 1986 (has links)
The potential for decreasing timber transportation costs in the South by increasing truck payloads was investigated using a combination of theoretical and case-study methods. A survey of transportation regulations in the South found considerable disparities between states. Attempts to model the factors which determine payload per unit of bunk area and load center of gravity location met with only moderate success, but illustrated the difficulties loggers experience in estimating gross and axle weights in the woods. A method was developed for evaluating the impact of Federal Bridge Formula axle weight constraints on the payloads of tractor-trailers with varying dimensions and axle configurations. Analysis of scalehouse data found log truck gross weights lower on average than the legal maximum but also highly variable. Eliminating both overloading and underloading would result in an increase in average payload, reduced overweight lines, and improved public relations. Tractor-trailer tare weights were also highly variable indicating potential for increasing payload by using lightweight equipment. Recommendations focused first on taking steps to keep GVW’s within a narrow range around the legal maximum by adopting alternative loading strategies, improving GVW estimation, and using scalehouse data as a management tool. When this goal is achieved, options for decreasing tare weight should be considered. Suggestions for future research included a study of GVW estimation accuracy using a variety of estimation techniques, and field testing of the project recommendations. / Ph. D.
67

Transborder transportation regulations and trade

Jones, John T. January 1996 (has links)
Thesis (Ph. D.)--University of Kentucky, 1996. / Includes bibliographical references (leaves 173-190).
68

A critical review on the planning of cross border vehicular traffic between Hong Kong and Shenzhen

Cheung, Yu-piu., 張裕彪. January 2001 (has links)
published_or_final_version / Transport Policy and Planning / Master / Master of Arts in Transport Policy and Planning
69

Improving communication in a transportation company by using a Web page

Logofatu, Cristina 01 January 2004 (has links)
The Internet has become a very powerful tool in improving communication, making it easier, more convenient, and faster to access or exchange information. This project takes advantage of the strengths the Internet provides by improving communication by developing a web site for a transportation company.
70

The determination of a database with respect to the transportation of hazardous materials by road in the PWV area

Carey, Graham Neil January 1992 (has links)
A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering. Johannesburg, 1992. / The formulation of effective safety measures to counteract the potential for disaster presented by the transportation of hazardous materials requires that reliable data is available as to the nature and extent of such traffic. Such data is currently unavailable and a roadside interview survey was conducted in the PWV area in order to ascertain the quantities and type of material being transported locally. the routes used, the types of vehicles and containers involved, and compliance with existing regulations. It was found that of the 1068 Vehicles surveyed carrying hazardous material, only 22% fully complied with existing legislation. A risk assessment model for use by both operators and authorities is then developed, in which the survey data is input to determine the least risk route between Johannesburg and Sasolburg. / AC2017

Page generated in 0.0357 seconds