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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.
401

Reforming a publicly owned monopoly : costs and incentives in railway maintenance

Odolinski, Kristofer January 2015 (has links)
The railway system is often considered to be an industry where a monopoly occurs “naturally”, which can explain the public ownership and the use of regulations. However, railways in Europe have been subject to reforms during the last three decades. The use of tendering has increased, which is a way of introducing competition for the market in absence of competition within the market. Still, contracting out services previously produced in-house places a heavy burden on the client, where contract design and its incentive structures can be decisive for the outcome of the reform. This dissertation provides empirical evidence on costs and incentives in a publicly owned monopoly that is subject to reforms, namely the provision of railway maintenance in Sweden. Essay 1 estimates the effect of exposing rail infrastructure maintenance to competitive tendering. The results show that this reform reduced maintenance costs in Sweden by around 11 per cent over the period 1999-2011, without any associated fall in the available measures of quality. Essay 2 estimates the relative cost efficiency between and within maintenance regions in Sweden. The results indicate considerable efficiency gaps together with economies of scale not being fully exploited. Essay 3 analyses the effect of incentive structures in railway maintenance contracts. An increase in the power of the incentive scheme reduces the number of infrastructure failures according to the results. In addition, the estimated effect of the performance incentive schemes suggests that more effort towards preventing train delays is made at the expense of preventing other failures. Essay 4 comprises an estimation of marginal costs of rail maintenance. The static model produces slightly lower marginal costs compared to previous estimates on Swedish data. The results from the dynamic model show that an increase in maintenance costs in year t - 1 predicts an increase in maintenance costs in year t. Indeed, there is an intertemporal effect that depends on the performed maintenance activities (governed by the contract design).
402

Vliv četnosti výměny olejové náplně vodoměrné vrtule na naměřenou rychlost / The influence of the frequency of changes oil on the measured speed by hydrometric propeller

Jurčová, Michaela January 2015 (has links)
This diploma thesis is focused at effect of time working hydrometric propeller between changes oil on measured velocity. From data what we have measured in laboratories of Department of water structures on the special small test track, we able to define size of measure bug, when we don´t change oil. One of outputs is graph of measure bug to measure time. Results of measure will be effect of oil.
403

Using Expert Modeling and Video Feedback to Improve Starting Block Execution with Track and Field Sprinters

Dyal, April 30 June 2016 (has links)
Correct formation during starting block execution is important for injury prevention and obtaining maximum velocity during the sprint. Researchers in applied behavior analysis have evaluated several procedures to improve performance in sports such as gymnastics, football, and, golf. A promising method to improve sports performance is expert modeling plus video feedback. However, there is little research on this method and it has yet to be evaluated with sprinters in track and field. Therefore, the purpose of this study was to evaluate the effectiveness of expert modeling and video feedback to improve form during block starts with track and field sprinters. Results revealed marked improvement from baseline to intervention across all four participants that was maintained at follow-up.
404

Acute rhinosinusitis during upper respiratory infection in children

Kristo, A. (Aila) 08 November 2005 (has links)
Abstract Acute rhinosinusitis is estimated to be one of the most common diseases in childhood. Still, the diagnostics and clinical relevance of this disease are controversial. Bacterial rhinosinusitis cannot be differentiated from mere rhinitis on clinical grounds alone. Abnormal radiologic findings have been found to be common in child and adult volunteers without sinus symptoms and in adults during viral upper respiratory infection. In children, the results of the few placebo-controlled studies on the benefit of antimicrobial treatment of clinically diagnosed acute rhinosinusitis are controversial. Bacteriologic cultures obtained from the middle meatus by rigid nasal endoscopy have been introduced as a way to determine the bacteriology of the maxillary sinus in adults, but they have not been studied in children with acute symptoms. In this thesis, incidental paranasal abnormalitites were found to be common in healthy school children examined by magnetic resonance imaging (MRI). Some of these abnormalities resolved during a follow-up period of 6 months, but new abnormalities appeared in some children. MRI abnormalities of the paranasal sinuses were found to be much more common in children with acute upper respiratory infections, and most of these abnormalities resolve spontaneously. Children with acute rhinosinusitis confirmed clinically and by imaging did not benefit from cefuroxime treatment as compared to placebo. Pathogenic bacteria (Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis) in the nasal middle meatus during acute upper respiratory infection predicted longer duration of the symptoms and signs of common cold. Based on these findings, imaging methods should not be used in the diagnostics of acute rhinosinusitis in children. Similarily, incidental imaging findings of abnormalities in the paranasal sinuses or in children with symptoms of acute rhinosinusitis are not an indication for antimicrobial treatment. Because middle meatal pathogenic bacteria were found to predict prolonged symptoms of upper respiratory infection, a randomized controlled trial is needed to evaluate the clinical value of middle meatal culture in identifying the children who would benefit from antimicrobial treatment during acute respiratory infection.
405

Petrology, structure and exhumation of the southern Sawatch mountains, south-central Colorado

Robbins, Rebecca January 1900 (has links)
Master of Science / Department of Geology / Mary Hubbard / The southern Sawatch Range of the Southern Rocky Mountains of south-central Colorado is composed of Precambrian crystalline igneous and metamorphic rocks that have undergone at least three major mountain building events during the Phanerozoic, the Ancestral Rockies Orogeny, the Laramide Orogeny, and Rio Grande rifting. In order to determine how the ancient basement structures might have influenced later episodes of deformation, a small area of basement terrain was mapped along the western margin of the Poncha Pass transfer zone between the San Luis and Upper Arkansas basins in the northern Rio Grande rift. The two dominant rock types in the map area, (hornblendic) amphibolite gneiss and (felsic) quartzofeldspathic gneiss, may represent interlayered metabasalt/metadiorite and metarhyolite/metagranite, with lenses of exotic lithologies throughout. Metamorphic foliations were found to be oriented predominantly N35ºW 47ºNE and to have had an influence on younger brittle structures related to the rifting episode. Lineations and fractures in the gneissic fabric also are parallel to brittle deformation structures. Apatite Fission-Track (AFT) analysis provided a means of determining when this crust was exhumed and cooled by the removal of overburden in response to erosion and/or tectonics. The resultant AFT age distribution revealed that exhumation occurred at the higher elevations during the Laramide orogeny (~299-46 Ma), and at lower elevations during Rio Grande rifting (~29-19 Ma). Although it is commonly thought that these mountains were exhumed during the rifting episode, the results of this study indicate that older events played a significant role in the exhumation.
406

A critical analysis of the impact of the fast track land reform programme on children’s right to education in Zimbabwe

Muyengwa, Loveness January 2013 (has links)
Magister Legum - LLM
407

Rôle de la couche intermédiaire dans le potentiel de la voie ferrée / Impact of the interlayer in the railway track behaviour

Calon, Nicolas 08 June 2016 (has links)
La présente thèse sur travaux a pour objectif de montrer l’influence de la couche intermédiaire dans le comportement de la voie ferrée. Par analogie, la couche intermédiaire peut être assimilée à la sous-couche sur les lignes ferroviaires récentes. Elle est présente sur les lignes classiques construites depuis le début du réseau ferroviaire français au milieu du XIXème siècle. Cette couche est située sous le ballast et contribue à la stabilité de la voie. Elle s’est formée au cours du temps par l’interpénétration entre le ballast et le sol support. Sa densification a été obtenue par le passage des circulations durant près de 150 ans. Le présent travail s’appuie sur trois thèses réalisées au cours de la dernière décennie. Ces recherches réalisées par Trinh (2011), Duong (2013) et Lamas-Lopez (2016) ont permis de mieux appréhender le comportement de cette couche en étudiant respectivement le comportement hydromécanique d’une couche saine ; le mécanisme de création et dégradation de la couche intermédiaire ; et enfin son comportement dynamique. Sur la base de ces travaux, en se basant sur les approches de dimensionnement des structures développées dans le domaine routier et sur les données de maintenance des voies ferrées de groupes 3 et 4, on a pu développer une nouvelle approche de dimensionnement permettant la prise en compte de la couche intermédiaire dans le bon fonctionnement de la voie ferrée. La finalité de ce travail est de développer une méthodologie d’analyse du comportement de la voie afin de prescrire les « justes travaux » (RVB, relevage, assainissement…) permettant d’atteindre les objectifs de performance visés / The aim of this PhD thesis is to show the influence of the interlayer in the behaviour of the rail track. By analogy, the interlayer can be comparable with the sub-ballast layer on the high speed lines. It is present on the conventional lines built since the beginning of the French railway network in the middle of the 19th century. This layer is located under the ballast and contributes to the stability of the rail track. It was formed over time by the interpenetration between the ballast and the ground support. Its density was obtained by the passage of trains for almost 150 years. This work is based on three PhD theses carried out over the past decade. The research conducted by Trinh (2011), Duong (2013) and Lamas-Lopez (2016) has allowed a better understanding of the behaviour of this layer by respectively studying the hydraulic behaviour of a good layer; the creation mechanism of and degradation of the interlayer; and finally its dynamic behaviour. On the basis of this work and on approaches of sizing structures developed in roads, and on the data of maintenance of railways of UIC 3 and 4, we can develop a new approach to sizing by taking into account the role of the interlayer in the performance of the rail track. A method of analysis of the behaviour of the rail track has been developed to prescribe “good job” (track renewal, lifting, drainage…) in order to achieve the performance objectives
408

The tractive performance of a friction-based prototype track

Yu, Tingmin 19 October 2006 (has links)
In recent years, the interest in the design, construction and utilization of rubber tracks for agriculture and earth moving machinery has increased considerably. The development of such types of tracks was initiated by the efforts to invent a more environmentally friendly vehicle-terrain system. These tracks are also the result of the continuous effort to develop more cost-effective traction systems. A rubber-surfaced and friction-based prototype track was developed and mounted on the patented modification of a new Allis Chalmers four wheel drive tractor. The track is propelled by smooth pneumatic tyres by means of rubber-rubber friction and the tractive effort of the track is mainly generated by soil-rubber friction between the rubber surface of the track elements and terrain. The experimental track layer tractor, based on an Allis Chalmers 8070 tractor (141 kW) was tested on concrete and on cultivated sandy loam soil at 7.8%; 13% and 21% soil water content. The contact pressure and the tangential force on an instrumented track element, as well as the total torque input to one track, was simultaneously recorded during the drawbar pull-slip tests. Soil characteristics for pressure-sinkage and friction-displacement were obtained from the field tests by using an instrumented linear shear and soil sinkage device. By applying the approach based on the classical bevameter technique, analytical methods were implemented for modelling the traction performance of the prototype track system. Different possible pressure distribution profiles under the tracks were considered and compared to the recorded data. Two possible traction models were proposed, one constant pressure model, for minimal inward track deflection and the other a flexible track model with inward deflection and a higher contact pressure at both the front free-wheeling and rear driving tyres. For both models, the traction force was mainly generated by rubber-soil friction and adhesion with limited influence by soil shear. For individual track elements, close agreement between the measured and predicted contact pressure and traction force was observed based on the flexible track model. The recorded and calculated values of the coefficient of traction based on the summation of the traction force for the series of track elements were comparable to the values predicted from modelling. However, the measured values of drawbar pull coefficient were considerably lower than the predicted values, largely caused by internal track friction in addition to energy dissipated by soil compaction. The tractive efficiency for soft surface was also unacceptably low, probably due to the high internal track friction and the low travel speeds applied for the tests. The research undertaken identified and confirmed a model to be used to predict contact pressure and tangential stresses for a single track element. It was capable of predicting the tractive performance for different possible contact pressure values. / Thesis (PhD (Argricultural Engineering))--University of Pretoria, 2007. / Civil Engineering / Unrestricted
409

Investigating the Experiences of Track Athletes during a Season-long Psychological Skills and Biofeedback Training Program

Stelfox, Kara B January 2012 (has links)
The purpose of this study was to explore the experiences of five track athletes (three men and two women, aged 18-33 yrs) during a season-long PST-Biofeedback training program designed to help them learn how to self-regulate physiologically, psychologically, and emotionally. Three key psychological skills were emphasized: focus (Janelle, 2002; Nideffer & Sagal, 2006), arousal control through biofeedback training (e.g., Bar-Eli, Dreshman, Blumenstein, & Weinstein, 2002), and debriefing (Hogg, 2002; McArdle, Martin, Lennon, & Moore, 2010). The program, which consisted of one-on-one initial and final semi-structured interviews with PST-biofeedback sessions in between, was individualized to meet each athlete’s needs and progress during the study. Results indicated that the athletes found the program helpful; they perceived an improvement in their ability to focus, debrief, and control arousal in the lab; and, to varying degrees, they transferred those skills into training and competition. The athletes also perceived an improvement in their sport performances.
410

Dopravní projekty mikroregionu Orlickoústecka / Transport projects in Orlickoústecko region

Kaplan, Ondřej January 2009 (has links)
This master thesis describes transport projects in Orlikoústecko region. At the first part it concerns on the general history of transport and actual trends in road, railway and cycle transport in European Union and Czech republic. In next part it characterizes Pardubice region and describes chosen transport projects in Orlickoustecko region. It focuses especially on legislation, financing methods and complete description of each project.

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