No description available.

No description available.

No description available.

No description available.

This thesis is concerned with advancing the modelling of indoor air flow and internal surface convection within dynamic whole-building simulation. The path taken is the conflation of computational fluid dynamics (CFD) techniques with dynamic whole-building simulation, with an accurate treatment of the co-dependencies between these modelling domains. Two flow responsive modelling techniques were devised and implemented within the ESP-r simulation program to achieve the research objectives. The adaptive convection algorithm enhances ESP-r's thermal simulation domain by dynamically controlling the simulation of internal surface convection. Empirical methods were extracted from the literature and a new method for characterizing mixed flow convective regimes was created to provide the algorithm with a basis of 28 convection coefficient correlations. Collectively these methods can calculate convection coefficients for most flows of practical interest. Working with this suite of correlations, the algorithm assigns appropriate equations to each internal surface and adapts the selection in response to the room's evolving flow regime. The adaptive conflation controller manages all interactions between the thermal and CFD modelling domains. The controller incorporates the latest turbulence modelling advancements applicable for room air flow simulation and possesses a suite of handshaking and thermal boundary condition treatments. The job of this adaptive conflation controller is to monitor the evolving thermal and air flow conditions in the room and dynamically select an appropriate combination of modelling approaches for the prevailing conditions. The two control schemes implemented to demonstrate the controller make use of a double-pass modelling approach. Each time-step that the thermal domain handshakes with CFD, the adaptive conflation controller performs an investigative simulation to approximate the room's flow and temperature field. Using these estimates, the controller calculates dimensionless groupings to determine the nature of the flow (forced, buoyant, mixed, fully turbulent, weakly turbulent) adjacent to each internal surface. This information is used to select suitable boundary condition treatments for each surface. A second CFD simulation is then performed using the refined modelling approach to more accurately resolve the room's air flow and temperature distribution, and to predict surface convection. In order to protect the thermal domain, a two-stage screening process is used to assess (and where necessary reject) the CFD-predicted surface convection estimates. These adaptive modelling techniques advance the modelling of indoor air flow and internal surface convection within whole-building simulation.

Many British and American critics have argued that the wartime 'Special Relationship' ended after World War H. Britain, buffeted by postwar shocks such as the end of Lend-Lease and atomic sharing, and by the lack of U. S. support during the Suez Crisis, felt increasingly demoted from its status as a great power, which had formerly been consulted by U. S. leaders on all matters of international importance. Despite those early post-war political dismissals, the USAF and the RAF began a Cold War linkage, which grew into a fifty-year association that was closer than any comparable defence relationship between nations. This work explores that unique relationship and argues that it grew even stronger through decades of mid-level air diplomacy clearly visible in the agreements and arrangements for U. S. Air Power in the United Kingdom. Its conclusions shed new light on the Anglo-American relationship and demonstrate the importance of air power in the diplomatic history of the two nations. It adds substance to the thin body of knowledge of air diplomacy, through an analysis of events, policies, agreements, arrangements, disagreements, and issues, which led to an even stronger transatlantic defence relationship that continues to serve both nations' interests

No description available.

The limitations in en-route Air Traffic Control today are generally accepted as being the workload and performance of the controller. This method of operation is known as the 'manual control process'. The manual control process is an open loop form of control, that relies heavily on controller judgement and decision making. Future developments in ATC, that use twoway datalink, and integrate air and ground systems, are expected to be delayed. This leaves the manual control process to manage the projected growth in air transport demand. An analysis was carried out of the manual control process on two sectors at the London Area & Terminal Control Centre at West Drayton. Particular attention was given to understanding complexity, the functions that controllers perform, decision making and information sources. A systems approach was taken to the analysis and used multidisciplinary research techniques. The study used naturalistic data collection. Both the ground and airborne systems were reviewed, and developments found within them, that can benefit the control process. An analysis of incidents in en-route ATC was also conducted. Proposals are made that can support an enhanced control process. These were modelled, and the results indicated that reductions in controller workload are attainable. The changes to the control process involve more close control of the vertical plane, and improved and more precise information being made available to the controller. It is suggested that aircraft flight management systems are used as a control tool, and system requirements are proposed.

In December 2000, Program Budget Decision (PBD) 096 changed the way the Department of the Navy (DoN) budgets for Arabian Gulf operations. The cost of operations is now required to be submitted as part of the annual budget vice funded as contingency operations. In order to justify increased funding of incremental costs for operations in the Gulf, a method to justify such budget requests must be developed. This research developed a regression model targeted at the intermediate and depot level maintenance cost trends for Air Conditioning (A/C) systems based upon the assumption that the severe weather factors of the Gulf would impact the maintenance of A/C equipment. The model used ship age, deployed operational tempo (OPTEMPO), and temperature factors as explanatory variables in the model. The results of the regression analysis indicate the model does not provide evidence of increased maintenance costs of A/C systems for operations in the Gulf. Based on the inconsistencies in the maintenance data and the limitations of the explanatory variables, it is recommended that this approach be excluded from further research to justify increased budget requests for operations in the Gulf. / US Navy (USN) author

The subject of this thesis is the simulation study of the development of extensive air show ers produced by very high energy gamma-ray and hadronic cosmic rays with respect to the Cherenkov light they produce, and its imaging in ground based telescopes. Chapters 1-4 are introductory: Chapter 1 covers the mechanisms responsible for the production of very high energy gamma-rays, whereas, chapter 2 focusses on the development of extensive air showers and Cherenkov light production. Chapter 3 covers the instrumentation used to measure the Cherenkov light using the imaging atmospheric Cherenkov technique. Chapter 4 covers known and possible sources of very high energy gamma-rays. Chapters 5, 6 and 7 cover research performed by the author: Chapter 5 discusses some of the differences between three popular extensive air shower simulations codes, namely ALTAI, CORSIKA and MOCCA. Chapter 6 details the simulation of the response of two ground based imaging atmospheric Cherenkov telescope (the Durham Mark 6 and stand-alone H.E.S.S. telescopes), and in particular details the derivation of the flux of the x-ray selected BL-LAC PKS 2155-304 with the Durham Mark 6 telescope. This represents the refinement of a published measurement given an improved telescope simulation. The significance of the signal seen is 6.8o, and the integral flux derived above 1.5 TeV (assuming a differential spectral slope of-2.6) is {2.5±0.7stat ± (^0.5)(_1.6syst) x 10(^-7) photons m(^-2) s(^-1) Chapter 7 discusses the importance of the atmosphere, and the results of shower simulations under different atmospheric assumptions are presented, which indicate the importance of atmospheric calibration for the new generation of Cherenkov telescopes. The results of this chapter suggest that to first order large changes in the low level aerosol concentration have a much more significant effect on the trigger rate of a stand-alone H.E.S.S. telescope, than on the Hillas parameter distributions seen. Chapter 8 brings together the work done in this thesis, and highlights a final set of fluxes for the active galactic nuclei sources seen with the Durham Mark 6 telescope, many of which will form future sources to be measured with the H.E.S.S. system. The current status of the stand-alone H.E.S.S. system is also covered in chapter 8. The thesis concludes with a further brief discussion of the future prospects for imaging atmospheric Cherenkov astronomy.