The decay of quantum turbulence in superfluid (_^4)He in the zero temperature limit wasinvestigated. Quantum turbulence was created by impulsive spin-down from a specific angular velocity to rest. A measurement of the vortex line density was performed using the scattering of charged vortex rings. The vortex line density decayed as L ∝ t^(-3/2) which is the characteristic of quasiclassical turbulence forced at large length scales. The interaction of metastable spin-triplet 〖He〗_2^* molecules with quantized vortex lines in superfluid (_^4)He at temperatures below 200 mK was studied too. The molecules were generated during an injection of electrons from a sharp metal tip at high voltage. They were detected as a current into a metal collector after ionization upon colliding with the collector surface. The detected current was suppressed by even a small rotation indicating the trapping of the molecules on quantized vortices. The presence of (_^3)He impurities at the level of 0.3 ppb strongly suppressed the detected signal. The temperature dependence of the detected signal showed a sharp peak, most probably associated with the condensation of (_^3)He atoms on vortex cores. The time of flight of the molecules as a function of temperature was measured. It was observed that there are three regimes for 〖He〗_2^* molecules transportation in superfluid (_^4)He : ballistic regime for T < 100 mK, diffusive for T > 200 mK, and an intermediate regime between them. The vortex lines were created by either rotation or ion injection. The trapping diameter of the molecules on quantized vortices was found to be 96 ± 6 nm at pressure of 0.1 bar and 27 ± 5 nm at 5.0 bar. It was also demonstrated that a tangle of vortices moving in superfluid (_^4)He are capable of conveying the 〖He〗_2^* molecules through the drift region.

The 1950s and 1960s witnessed a period of mass immigration to the UK from former colonies. One of the outcomes of this inward migration was that the children of immigrants entered the UK higher education (HE) systems in order to maximise their life opportunities. Despite their entrance in HE, there is a body of evidence showing that an educational attainment gap at degree level exists between BME students and their White counterparts, even when at the point of entry BME students and their counterparts have nearly identical entry grades, hence showing they are equally equipped. The shortfall between the performance of BME and White students has implications for the sector and society per se. So that a better understanding for the rationale of the degree attainment gap could be gained, adding to the quantitative research demonstrating this gap, 20 qualitative research interviews amongst first and second generation university attendees were completed. To support this work, a case based study approach at Coventry University was undertaken which enabled a deeper understanding of the reasons for specific attainment. The research findings reveal that a number of factors have an influence. The factors are external, namely previous experience at school and the route taken to reach HE, course aspects in relation to the one that is chosen and teaching staff. Internal factors centre on attitudes and aspirations, peers and the individual’s knowledge of HE. The final area to emerge is a middle ground, the image of the institution and its ability to make students feel welcome. Educationalists can do little to influence external factors; however, institutions must take action, through curricular changes, course materials and attitudes of tutors, to minimise their negative impact upon attainment. Attainment statistics demonstrate that the gap has started to reduce; however, it still needs addressing further as degree attainment has the ability to impact individuals’ lives and their employment opportunities. Institutional actions can improve the attainment of all HE students.

En el mundo de la construcción, el concreto juega un papel sumamente importante, ya que la mayoría de las obras que nos rodean han sido hechas con éste. Una de las características que todo trabajador de la construcción busca darle a su concreto fresco es: la trabajabilidad, tanto para el mezclado como para el colado. Lográndolo muchas veces agregando agua a la mezcla, variando así la relación agua/cemento con la cual ha sido diseñada, por lo que afecta notoriamente la calidad del concreto, disminuyendo de forma considerable la resistencia del mismo. Este problema no es nuevo, ha existido desde que se creó el concreto, es por eso que ha surgido el diseño de un concreto de alta fluidez, al que se le denomina un concreto con una reología parecida al de un autocompactado, sin llegar a serlo; que viene a solucionar los problemas de colado en estructuras muy reforzadas o de difícil acceso de vibradores. En el Perú se conoce muy poco sobre este tema, por lo que no ha sido muy aplicado, ya que requiere del uso de aditivos químicos y de un estricto control de calidad. El presente estudio pretende dar a conocer a la industria de la construcción todo lo relacionado a este tipo de concreto, es decir; sus características, ventajas, aplicaciones, materiales a utilizar, ensayos a practicarle (equipo, procedimiento y manejo de resultados), y las resistencias logradas con mezclas hechas con materiales de nuestro medio en distintas cantidades de cemento Sol Tipo I.

With the role of purchasing evolved from a paper pushing function to a strategic and value creating player in global businesses (Espich, 2004), the activities of purchasing professionals today are knowledge- and competence driven. The purpose of this study is to identify the competency needs of purchasing professionals at DFS Deutsche Flugsicherung GmbH (DFS), Europe’s largest Air Navigation Service Provider (ANSP). It also seeks to explore the role of implicit participant knowledge in the process of competency identification and model development. For these reasons, a mixed-method case study at DFS is conducted. After reviewing the literature, a purchasing competency model is developed from scratch through exploring the target population’s self-image on competency needs and by contrasting these results to the view of purchasing department’s internal customers and management. The so developed model is then verified through participant observations and the identification of the implicit knowledge of competency needs of purchasing professionals. The study contributes to business practice and the theory of competency modeling. It identifies competencies in an area where little is known about competency requirements and explores the need to consider implicit participant knowledge in the model development process. The research outcomes are valuable to solve a real-world problematic situation through developing an activity based, multi-perspective and future oriented competency model. The study provides an example of how the aspect of implicit knowledge can be integrated when studying competencies. Results from this case in Europe’s leading ANSP are likely to be transferrable to other companies in the industry.

The selection of freight transport mode in cities like Hong Kong, with little land, is in some respects obvious. The deciding criterion for mode/carrier selection is based on the selection of either the lowest total transport cost or the shortest transit time for the cargo. The peculiar nature of each transport mode, namely; rail, sea, road and air, will definitely earn their own places when shippers need to make a decision on their shipments. The nature of the cargo will also affect the choice of carrier/mode when they are transported in break bulk. Fortunately, the invention of ISO containers in the late 1950s eliminated and overcame the shortfall in some transport modes. With the extensive usage of ISO containers hereafter, shippers can now enjoy a much freer choice of transport mode. When China started its open-door policy in the late 1970s, many local (Hong Kong) manufacturers relocated their factories to the Pearl River Delta (PRD) due to the low labour and land costs. Delivery of shipments was mainly carried out by Hong Kong freight forwarders as they had been in business with the shippers for decades. Road transport was the only mode choice available at that time due to the inflexibilities in other transport modes such as sea and rail. Progressively, these factories were relocated northwards at a later time due to the gradually increasing labour and land costs. Freight forwarders were then faced with a prolonged delivery time due to the stringent Customs regulations in China as well as a progressive increase in the physical distance between the factory and the loading port in Hong Kong. The continuous developments in adjacent ports in Southern China offered freight forwarders an opportunity to revise the route of consignments so that the lowest cost and shortest transit times were achievable. Nowadays, consignments from the PRD region can be transported to the loading ports via at least three transport modes, namely, sea (barge), road (truck) and rail. In addition to physical constraints in the mode/carrier selection, the mode choice in China is further complicated due to the inflexible Customs regulations and government policies on tax rebates. Considerable research has been done on mode and carrier selection for bulk cargo in Western countries. However there is no explicit study on the mode choice in China. This thesis studies factors that will affect the shippers’ mode/carrier choice and ascertains the unique key factors that will affect their mode/carrier choice in the PRD for their overseas consignments. From this study, it was observed that shippers irrespective of the consignment size and cargo value prefer to use a loading port that is reliable and efficienct in operation. This is the first thesis written about carrier mode choice in China applying systematic and rationale methods to express the mode selection criteria in PRD area. The results were achieved by using the pairwise comparison method - Analytical Hierarchy Process (AHP) method so that rigidity of the results is academically accepted. Nevertheless, further study on the mode choice can be carried forward through assessing buying behaviour and the shipper-carrier relationship.

Port efficiency is a significant element that stimulates port competitiveness and enhances regional development. With increasing international maritime traffic and changing technology in the maritime transport sector, containerisation and enhanced logistic activities, infrastructure might be one of the main determining factors of port competition (Merk & Dang, 2012). Due to the increasing container traffic and the high quality of service required by the shipping lines, Mediterranean container ports are being compelled to enhance port efficiency to improve comparative advantages that will increase cargo traffic and satisfy the customers’ requirements. The Mediterranean Sea is a link point between Europe, Africa and Asia. This research aims to examine the impact of ports' technical efficiency on the improvement of Mediterranean container ports’ competitiveness. The research analyses the competitiveness and the relative efficiency of the top 22 container ports in the Mediterranean basin using a cross-section, panel data and window analysis application of data envelopment analysis (DEA) for the period between 1998 and 2012. The selected 15 year period enables the analysis of Mediterranean container port market dynamics and the benchmarking of the technical efficiency of the selected ports for three consecutive market cycles. This research can be classified as quantitative analytical research. The research follows the concept of the Industrial Organization (IO) and the Structuralism (Harvard school) methodology that analyses the market Structures, Conduct and Performance (SCP) of market players. The study conducts a simultaneous three-stage procedure: in the first stage, the competitiveness of the main container ports in the Mediterranean is analysed through the study of market structure and conduct. Market structure is assessed through measuring and analysing market concentration by using four different methods. These methods are: the K-Firm concentration ratio (K-CR), Hirshman-Herfindahl Index (HHI), the Gini coefficient (GC) and the generalized entropy index. Boston Consultant Group (BCG) matrix is also used to visualize the dynamics between ports in the defined market and assess the ports' competitive position. Market conduct is analysed using shift-share analysis (SSA) to get a thorough understanding of the issue of port traffic development. In the second stage, market performance is analysed through the use of the non-parametric models of Data Envelopment Analysis (DEA) which estimates the relative efficiency scores and ranking seaports according to their efficiency. Five DEA models are adopted for comparative purpose, the DEA- CCR, DEA-BCC, the Super-Efficiency (A&P, 1993), the sensitivity analysis and slack variable analysis models. In the third stage, to examine the impact of port efficiency on port competitiveness, a number of hypotheses are examined through the use of parametric correlation coefficients (Spearman’s rank order) and Simar and Wilson (2007) procedure to bootstrap the DEA scores with a truncated regression. Using this approach enables more reliable evidence compared to previous studies analysing the efficiency of seaports. The main findings demonstrate that the recent deconcentration tendency of the Mediterranean container port market is due to the increased number of market players which will in turn reshape the market structure, change the container port hierarchy and intensify the competition between ports as the market shifts from oligopoly to pure competition. The research findings also reveal the existence of inefficiency pertaining to the management of container ports in the region, since the total technical efficiency is found to be below 50% on average. This relatively limited technical efficiency of the Mediterranean container ports indicates the need for appropriate capital investments for ports’ infra/superstructure. In particular, those ports whose efficiency is not favoured by some factors such as size, geographical position and socio-economic conditions of the region in which they are located, must adopt suitable reform strategies to promptly improve their efficiency and competitive position. What differentiates this work from previous studies on the subject is that both cross-sectional and panel data have been collected and analysed at the level of individual container ports in the Mediterranean. The study is based on a wide range of methodologies, both parametric and non-parametric, that have ensured the validity of the empirical examination that has been undertaken and the results obtained. The research analysed the Mediterranean container ports competitiveness, benchmarked and ranked their efficiency by considering the Mediterranean in its totality, including South Europe, Middle East and North Africa. The study puts forward a way to assess container port efficiency based on simple, yet validated and meaningful physical efficiency measures.

The integration of low-temperature thermochronometers, including apatite and zircon (U-Th)/He (AHe, ZHe) and apatite fission-track (AFT) methods, allows for a quantification of the thermal history experienced by rocks as they heat and cool through upper crustal temperature regimes (<200°C). Whereas these methods are practical in geologic terranes that have undergone rapid cooling, application to strata with protracted cooling histories is complicated by the enhanced role of grain-specific parameters (volume, chemistry, radiation damage) on the kinetics of helium diffusion and fission track annealing. The effects of these variables are most prevalent in sedimentary samples, where natural variance in detrital accessory mineral populations results in a broad range of diffusion kinetics and great dispersion in corresponding cooling dates. This thesis integrates contemporary thermochronometer diffusion and annealing kinetics to investigate the burial and exhumation history of two natural laboratories. In the Mackenzie Mountains and Plain of the Northwest Territories, long-term radiation damage accumulation in zircon from Neoproterozoic siliciclastic units produces ZHe dates that track Albian to Paleocene burial and exhumation in front of the foreland-propagating fold-thrust belt. For the Phanerozoic stratigraphic section, AFT annealing kinetics are calculated from Devonian and Cretaceous samples, and are incorporated into multi-kinetic AFT modeling. These kinetics also constrain AHe date-radiation damage trends, and when combined allow for an estimation on the magnitude of eroded sediment across regional pre-Albian and post-Paleocene unconformities. Finally, conodont (U-Th)/He data from Anticosti Island, Québec in the Gulf of the St. Lawrence are compared with ZHe, AHe and AFT data to test their utility as a thermochronometer for carbonate basin analysis. These data evince a Mesozoic thermal history previously unattributed to the region. Ultimately, this thesis provides a novel assessment on the ways in which thermochronometer date dispersion can be quantified to assess the thermal evolution of sedimentary basins from burial through to inversion.

The continuous implementation of highly technological functions and specifically intelligent transport systems in public transport highlights the need of highly efficient, accurate and reliable bus operations network. Intelligent transport systems can support a variety of functions, including dynamic bus fleet management which has yet to be established in most bus fleets in the UK in a systematic way. In order to support dynamic bus fleet management by detecting the fundamental role of bus and traffic incidents in bus-based public transport, a microscopic simulation model capable of modelling the impact of the individual incidents‟ characteristics on bus operations has been developed and applied to a variety of scenarios. This research draws on a review of existing literature on bus fleet management and available computer software in this field. It investigates research gaps in modelling the impact of traffic incidents on overall bus performance; it describes the design and development of the new simulation model, SIBUFEM (Simulating Incidents for Bus Fleet Management) for modelling bus operations during whole day periods in which incidents of different types can occur. The model simulates a high frequency bus service using existing field data and incorporates the continuous circulation of buses along the bus route. It uses journey time profiles, passenger-dependent bus stop dwell times and deterministic time-dependent queuing theory to model traffic incidents and the impact of their characteristics on the bus performance parameters. The model results, presented in this thesis, focus on performance measures including but not limited to bus journey times, passenger waiting times and bus delays resulting from various bus and traffic incidents. Incidents vary from bus breakdowns, to traffic incidents such as road-works, traffic accidents, burst water mains, disabled vehicles and illegal parking; in SIBUFEM they are specified in terms of their location, duration and severity (i.e. loss of capacity). The model has been applied to a main bus corridor in Southampton, UK, with a base case of „normal‟ operations established, for comparison with results from 24 different incident scenarios, and using key model performance parameters of average bus journey time, bus speed and excess waiting time. This PhD demonstrates the functionality of SIBUFEM with model results demonstrating the extent to which passenger waiting times increase with increasing incident severity and duration. The overall comparison of the simulation results showed that the more severe the level of severity or the longer the duration of an incident, the higher the expected impact of the event on the overall bus performance was. In terms of the incident location parameter, the effect is greater when the incident occurs in the middle of the bus route than when it occurs at the end. The effect of incident location is especially evident in the case of traffic incidents such as roadworks, traffic accidents and illegal parking. Findings from this research also demonstrated that these incidents are usually more severely affected by a change in an incident parameter than by bus breakdown incidents. The thesis concludes with a discussion on potential dynamic bus fleet management strategies and how SIBUFEM can be further developed to allow these strategies to be evaluated. SIBUFEM is capable of modelling traffic incidents to support dynamic bus fleet management and, thus, encourage the use of intelligent transport systems applications in bus operations. This offers great potential in the field of bus-based public transport as part of a guidance tool for bus operators, as well as the way to increase bus level service thereby increasing customer satisfaction and thus the development of a sustainable transport system.

Are transport markets and associated costs important for international trade? To the present day there is a sparse and fragmented literature pointing towards an affirmative answer. This Thesis reinforces such opinion by accounting for transport markets in general equilibrium models of trade, and providing empirical evidence on the impact of determinants that explain casual trade-and-transport related phenomena. The outcomes of the Thesis promote policy and/or investment activism in developing countries, due to the gains from trade lost to excessive transport costs. Two particular observations are investigated: i) When and why should a transport hub emerge? Using a simple trade model of monopolistic competition with representative firms incorporating network theory, the determinants governing optimal network formation become the level of transport costs, increasing returns in transportation and centrality. Empirical deduction supports that exports increase more on average if a shipping route passing through a hub is selected relative to a direct route, following a reduction in variable trade costs. Thus geographically disadvantaged countries that absorb high transport costs can ameliorate these by trading via a hub. ii) Are tariffs and shipping prices complementary? By not assuming this interaction, standard trade models of representative and heterogeneous firms are unable to identify by decomposing the direct and indirect -that is, via adjustments in transport technology- effects of trade liberalisation, resulting in observing large elasticities of import demand. Invoking a model of monopolistic competition with heterogeneous firms that trade using transport services operating under increasing returns, it is the presence of the latter that amplifies the response of trade volumes to tariffs declines. Yet transportation may also dampen such responses, for the shipping price is a function of the factory price of the good and a markup. The empirical experiments provide support to such propositions. The last chapter is distinct and deliberates on the importance of modeling financial networks that represent real world transaction systems relative to abstract artificial topologies. It is found that the international network of financial exposures exhibits characteristics that are congruent with robust-yet-fragile networks. Employing a common model of contagion illustrates how the robust-yet-fragile network structure absorbs defaults by peripheral countries however becomes susceptible to default cascades when combinations of peripheral countries or a financial centre collapse.

Sustainability is a broad concept which embodies social, economic and environmental concerns, including the possible consequences of greenhouse gas (GHG) emissions and climate change, and related means of mitigation and adaptation. The reduction of energy consumption and emissions are key objectives which need to be achieved if some of these concerns are to be addressed. As well as being an important component of sustainability in other sectors, a good transport system needs to be sustainable in its own right. Energy consumption and GHG emissions are important issues within the transport sector; in the European Union (EU), for example, transport is directly responsible for between 25 and 30 percent of all carbon dioxide (CO2) emissions, and the inclusion of indirect (Scope 2 and Scope 3) GHG emissions may increase this proportion further. If reduction targets are to be met, it may be necessary to encourage behavioural change, including modal shift from those modes of transport which are comparatively highly polluting, towards those modes which pollute less. Rail is potentially a suitable target for such modal shift from road transport (notably the private car for passenger travel) and, in some case, from short-haul and domestic aviation. However, modal comparisons are often based on average data, and are reliant on a number of assumptions. There are likely to be some circumstances where modal shift towards rail makes more sense than others, but the use of average data does not enable policy makers to be discerning. It should also be noted that many modal comparisons are also based purely on operational energy consumption and emissions, and neglect to take the whole life-cycle in to account. Embedded energy and emissions from the construction of vehicles and infrastructure can be quite significant, as can the energy consumption and emissions from vehicle idling in the case of public transport modes. After considering the concept of environmental sustainability, this research begins by reviewing existing energy consumption and emissions data for vehicle operation, where it is noted that data for cars in Europe are quite comprehensive. Manufacturers are obliged to publish fuel consumption and emissions data for each model of car they sell, although the type approval tests do not reflect real-world performance. Studies are reviewed which suggest that the gap between the tests and the real-world has been widening in recent years. The gap appears to be independent of the size of vehicle, but is larger for hybrid vehicles than it is for those powered solely by a petrol or diesel internal combustion engine. Data for trains are less comprehensive, and that data which are available are often based on a limited empirical sample, or simulated data for which a number of assumptions have been made. Sometimes, the details of the measurements taken or simulation parameters used are unclear. As a result, published data for a particular type of train in the literature are sometimes found to vary significantly. In order to make more informed comparisons between rail and other modes, two large empirical datasets have been analysed. Two UK Train Operating Companies (TOCs) have also made data from energy metering systems on-board their electric trains available, which have been used to analyse the actual energy consumption of different trains over a number of different routes. The sample size is far larger than that found in literature to date, and it has been possible to consider variation between routes and service types. The v basic principles of simulating the energy consumption (and related emissions) of a train have also been illustrated, and a software tool has been developed for Arup so that it can now make some estimate of operational energy consumption and emissions for a given train over a given route. The aforementioned empirical data have also been used to validate the tool and suggest some appropriate simulation parameters. A review of existing literature concerning whole life-cycle analysis has been undertaken. It is clear that life-cycle costs vary significantly but in general, the overall life-cycle costs of rail appear to be higher than those for any other mode. The biggest additional factors appear to be the embedded carbon and energy in the infrastructure, particularly for a system comprising a lot of bridges, tunnels and large underground stations. For the vehicles themselves, trains typically have a longer lifespan than cars, which reduces the embedded carbon and energy as functions of time. When comparisons are made between modes, passenger-km is a metric which is often chosen, because it helps account for some of the fundamental di�erences between modes, including the fact that public transport modes usually use vehicles which are much bigger than the private car. In order to make comparisons on this basis, however, something about the load factor must be known. The sensitivity to load factor is demonstrated, and the earlier empirical data analysis is used to illustrate the benefits of longer trains. A discussion then follows about the potential pitfalls of making comparisons purely on a per passenger-km basis. This thesis ends by summarising some of the �ndings. Some consideration is given towards the future and the fact that technological developments are being made in Sustainability is a broad concept which embodies social, economic and environmental concerns, including the possible consequences of greenhouse gas (GHG) emissions and climate change, and related means of mitigation and adaptation. The reduction of energy consumption and emissions are key objectives which need to be achieved if some of these concerns are to be addressed. As well as being an important component of sustainability in other sectors, a good transport system needs to be sustainable in its own right. Energy consumption and GHG emissions are important issues within the transport sector; in the European Union (EU), for example, transport is directly responsible for between 25 and 30 percent of all carbon dioxide (CO2) emissions, and the inclusion of indirect (Scope 2 and Scope 3) GHG emissions may increase this proportion further. If reduction targets are to be met, it may be necessary to encourage behavioural change, including modal shift from those modes of transport which are comparatively highly polluting, towards those modes which pollute less. Rail is potentially a suitable target for such modal shift from road transport (notably the private car for passenger travel) and, in some case, from short-haul and domestic aviation. However, modal comparisons are often based on average data, and are reliant on a number of assumptions. There are likely to be some circumstances where modal shift towards rail makes more sense than others, but the use of average data does not enable policy makers to be discerning. It should also be noted that many modal comparisons are also based purely on operational energy consumption and emissions, and neglect to take the whole life-cycle in to account. Embedded energy and emissions from the construction of vehicles and infrastructure can be quite significant, as can the energy consumption and emissions from vehicle idling in the case of public transport modes. After considering the concept of environmental sustainability, this research begins by reviewing existing energy consumption and emissions data for vehicle operation, where it is noted that data for cars in Europe are quite comprehensive. Manufacturers are obliged to publish fuel consumption and emissions data for each model of car they sell, although the type approval tests do not re ect real-world performance. Studies are reviewed which suggest that the gap between the tests and the real-world has been widening in recent years. / The gap appears to be independent of the size of vehicle, but is larger for hybrid vehicles than it is for those powered solely by a petrol or diesel internal combustion engine. Data for trains are less comprehensive, and that data which are available are often based on a limited empirical sample, or simulated data for which a number of assumptions have been made. Sometimes, the details of the measurements taken or simulation parameters used are unclear. As a result, published data for a particular type of train in the literature are sometimes found to vary significantly. In order to make more informed comparisons between rail and other modes, two large empirical datasets have been analysed. Two UK Train Operating Companies (TOCs) have also made data from energy metering systems on-board their electric trains available, which have been used to analyse the actual energy consumption of different trains over a number of different routes. This thesis ends by summarising some of the findings. Some consideration is given towards the future and the fact that technological developments are being made in both the motor and the rail industries.