NPS Hall of Fame author (Presented April 23, 2005) / Real time simulation of the time-dependent behavior of low power thermal reactors is amenable to analog computer techniques. This paper presents the basic physical concepts relative to thermal reactor operation, a derivation of the governing transient equations noting simplifying assumptions, and the development of the analogous electrical circuit to ultimately provide solutions to these equations. In addition, many special problems involved in the simulation of a specific reactor are discussed and analyzed in detail. As a result, the successful design and construction of a simulator whose time-dependent behavior closely approximates that of an actual reactor is demonstrated. The reactor simulated is the Aero jet -General Nucleonics low power thermal reactor (AGN-201) currently installed at the United States Naval Postgraduate School, Monterey, California. Flux-time recorder plots for various sequences of operation of reactor and simulator are included to indicate the degree of simulation attained.

The three elastic constants of tantalum, tungsten and molybdenum have been measured in the temperature range between 4.2 and 300 K. The directly measured quantities C and —(C^-C. J for molybdenum and the computed bulk moduli of all three 'elements show an anomalous temperature dependence. These data along with published results for other metals generally show a difference in temperature dependence of the bulk modulus between 3d and 4d-5d metals. Overlap contributions to the elastic constants are found to favor an antiferromagnetic ordering. The Debye characteristic temperatures calculated from elastic constants are found to be in substantial agreement with results obtained from calorimetry.

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Nowadays, power systems are interconnected together to provide a reliable and secure source of the energy to the consumers and operate in lower operating cost than if they being run separately. As the most important reason for interconnecting power systems is to improve the economic aspects in operation of the entire system, this interconnection between power systems would provide the following economic advantages: 1) lower overall congestion costs for consumers; 2) more consistent prices across the areas; and 3) lower operating cost due to presence of broader pool of mutual benefits shared between systems. In addition, in the event of an emergency in any individual system, such as a shortage of generation capacity and a network outage, an interconnected power system can utilize all available power generation resources and delivery facilities throughout the entire grid to adjust the transferring power among systems, thus guaranteeing a continuous power supply to customers in their regions and achieving a high-level power system reliability. Also, in the event of transmission line congestion, the interconnected power systems can work closely together to remove the congestion from the entire power grid. The main motivation of this dissertation is to provide methodologies which enable different regional/virtual system operators to efficiently schedule their regional generation resources and optimally coordinate their operations with other neighboring areas while the respecting the information privacy between individual systems. Our proposed methodologies rely on decentralized solution philosophies. Using these methods, the original large-scale problem can be divided into several scalable and tractable subproblems that can be coordinated with each other to find out the optimal operating point of the entire system using either sequential or parallel calculation. Furthermore, by providing the flexibility to define the boarder of the areas, the decentralized solution methodologies can be also utilized to accelerate the solution process of the decision making in a large-scale power system where enormous number of variables should be accommodated into the problem formulation

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Fuelled by rapid urbanisation, urban spatial expansion is increasingly encroaching on the rural hinterland of large metropolises around the world, making a type of spatiality referred to as the “peri-urban” an important focal point for urban studies. Peri-urban residential settlement development in Chinese cities has been put on a fast track in recent years, however, its current situation has been little documented and its implications for sustainability not well understood. The main contributions of this research to the existing literature is considered to be two-fold: Firstly, this research has filled the research gap by providing a more up-to-date empirical study of peri-urban settlement development in the Chinese city of Tianjin with a specific focus on residential settlements and presenting the current and emerging challenges that face sustainable peri-urban settlement development; Secondly, this research has also made contributions to research in the context of sustainability by adopting an integrated research methodology that combines case-study-based systemic evaluation with assessment of stakeholder perspectives and decision-making dynamics. In this study, a theme-based evaluation framework is developed and used to assess the sustainability outcome of three recently developed peri-urban residential settlement cases in Tianjin, China, with each representing one typical peri-urban settlement type, i.e. rural resettlement project; affordable housing compound; and suburban commercial housing estate. Their specific approaches to achieving sustainable development are discussed, and remaining problems and challenges are identified and analyzed with suggestions for the complementary approaches and progression in the planning and management of peri-urban settlements. The evaluation framework is also used to examine the perceptions of the stakeholders of urban development on peri-urban sustainability. By making a comparison between the delivered sustainability outcome of the settlement cases and the stakeholders’ perceptions on sustainability, it was revealed that lower levels of sustainability performance in the settlement development outcome coincided, to a large extent, with lower levels of conformation on the conceptions of sustainability between the decision-makers of the development and the residents of the communities developed.

Sustainable development related design and research has shown a focus shift from new building projects to existing ones; from the building scale to the regional and the urban scale; from construct and assessing the energy performance of buildings to participating at an earlier design stage. Taipei has been selected as the subject of this research due to its extremely high urbanization and huge pressure from the existing built environment. In order to achieve the national goal for reducing CO2 emissions, appropriate localized guidelines for buildings are urgently needed. Therefore, this research aims to understand, analyze and predict the energy performance of the architectures in Taipei, and offers a series of design strategies to help reduce the energy demand at building and urban scales. This will be achieved through the application of modelling, integrating SketchUp (@Last Software 2000), HTB2 v2.10 (WSA 2008; Alexander 2008), and Virvil Plugins (WSA 2012; Jones et al. 2011). The whole research process is a two-phase study. The first phase is to create models at different scales based on observation of the practical building environment, analysis of architecture related data and practical situations in Taipei, and then simulate them in a bottom-up method to understand the fundamental energy performance of different buildings, groups, blocks and districts. In the second phase, the model is extended to examine important variables and related strategies at both building and urban scales. This research finds that lighting, equipment efficiency, temperature settings of AC systems, orientation, glazing ratio, shading devices, and wall-to-volume ratio are important variables for architectures at building scale. Furthermore, development intensity, block usage type, wall-to-volume ratio, volume rate, building coverage ratio, average building height, surrounding road width, over-shading, insulation and outdoor environment are comparatively critical at urban scale. Additional interesting findings showed that the impacts brought by orientation, shading device, and insulation are not consistent at different scales. Lastly, some guidelines are presented to be used as a reference for new and existing buildings.

Public spaces of a city's neighbourhoods and residential areas are one of the key indicators of urban quality. In Libya, in 2005, the government introduced a redevelopment scheme to provide new homes to the local residents and to build thousands of new housing units around the country. This initiative was to offset the shortage in housing numbers due to the rapid population growth and urbanisation. In 2011, 79% of the country's population lived in urban areas. This high demand for housing by Libya's citizens drove significant changes to the urban planning composition of the country, particularly the residential areas. The government claims that this new strategy aims to fill the shortage of houses within as short a time as possible. This research focuses on two examples of a typical neighbourhoods as case studies in Misurata City, Libya. It investigates the role of public spaces in the traditional neighbourhoods (TNs) and the governmental neighbourhoods (GNs). It compares the conditions of public spaces in both types of neighbourhoods in terms of physical and intangible qualities and examines the relationship between the residents in terms of social integration and community cohesion. In addition, the researcher examines whether this new strategy has affected the social relationships within the local community or not and assesses the extent of the possible impact on the daily activities of residents. Furthermore, the thesis discusses the extent of interaction among the residents regardless of their age, gender and cultural background. The main aim of this research is to examine the satisfaction of the public spaces' users through measuring the social value they ascribe to it, and the level of interaction they engage in. The research includes a case study to draw a clear picture of the existing situation and contributes a framework for future studies. It has been suggested by many scholars and professionals that the appropriate research approach in such a study is the mixed methods approach which combines quantitative and qualitative methods in the case study. The research compares the results of the questionnaires that were distributed to an adequate sample of the neighbourhoods' population, and in-depth interviews with three categories- a) residents b) decision makers and c) professionals. Additionally, site observation was used to focus on the residents' activities in the public space which might be difficult to collect by the former tools. Data were analysed using Statistical Package for the Social Sciences (SPSS) to find out the significant correlations of the main themes of the study, and NVivo was also used to analyse the in-depth interviews which suggested several important findings. The case study includes two sites, 1) 9th July Governmental Neighbourhood (GN) and 2) Almegawba Traditional Neighbourhoods (TN) in the city of Misurata, Libya. Two hundred (200) questionnaires were distributed to the two sites, Almegawba neighbourhood and 9th July neighbourhood, and 158 forms were returned, 78 from GN and 80 from TN. The questionnaires include a number of open-ended, closed and multi-choice questions. Sample selection was obtained using a snowball technique. Participants were recruited to take part in the research through an invitation from other residents and so on. The next step was conducting the interviews for further in-depth information. In-depth interviews were conducted to provide a further understanding of the existing situation as well as to reveal clearer features about the quality of the public space of the case study. Moreover, they enabled the researcher to collect appropriate evidence that clarifies the research issue and contributes to solving the research matter and creating a coherent framework to be used in the future policies. A total of 16 interviews conducted during the field work with four Decision makers, four Professionals, four Residents of Governmental Neighbourhoods (GNs) and four Residents of Traditional Neighbourhoods (TNs). Results have shown that public space plays an essential role to strengthen the relationships between the residents of the neighbourhoods. The findings highlight that residents in traditional neighbourhoods feel more attached to their community, socially satisfied and comfortable while this perception was lower in the governmental neighbourhoods. Findings also highlighted that when public spaces of the neighbourhoods are well-prepared and provided with an appropriate range of physical settings, this will have a positive influence on the social satisfaction of the residents. The research also found out that relationships between the residents of the neighbourhood play an essential part to improve and promote the social satisfaction of the residents which lead to high-quality communities. Hence, they contribute effectively to the development of the urban quality throughout the city. A new future direction is to find out how the neighbourhoods of the city can be linked together, and how urban designers can create schemes that can improve the relationship between the communities of the city as one linked/integrated community.

This research aims to identify viable design strategies that can improve the indoor thermal comfort within the workplaces of existing multi-storey ready-made garment (RMG) factories in the tropical climate of Bangladesh. The research framework was initially developed through literature reviews and a feasibility study on the applicability of a passive design approach within an existing RMG factory. The principal research follows the empirical case study approach collecting environmental data for three types of workspaces (i.e. cutting, sewing and finishing sections) and subjective responses from the workers, designer and owners of three multi-storey case study buildings during the three main climatic seasons (i.e. cool-dry, hot-dry and warm-humid seasons) of Bangladesh. In addition to field studies, a validated simulation study is also completed in one of the case study buildings. Analyses of the subjective votes established workers' preferred thermal comfort range for temporal varieties of the climate and suggested that the distance between their workstation and ventilation-inlets should be maintained within 12m to 18m for more personalised control on their comfort avoiding the ceiling fans. Analyses of the environmental data from all case study buildings indicated that the limited effective openings of the existing windows and the ventilation strategy being limited to only occupied hours influence the thermal environment of RMG workspaces. Building owners saw value in implementing two solutions (i.e. altering existing window type to one with a higher effective opening area and utilising a night-time ventilation strategy with thermal mass) immediately in their existing buildings as well as new buildings. Simulation results confirmed that these two interventions can provide reductions of up to 23% of working hours when high temperature is experienced. Moreover, designing stack induced ventilation through shafts and changing functional arrangement can provide additional air speed (increase of up to 0.45 m/s) improving workers' thermal comfort. Though this research includes limited number of case studies in sub-urban context lacking the representation of the total building stock of Bangladesh, the research methodology and key findings can still be used as a reference by architects and engineers involved in refurbishing existing workspaces or designing new RMG factories in Bangladesh and similar tropical regions. Findings can be adopted by owners and workers of the case study buildings for improving their workspaces. The thermal comfort guidelines and workable strategies can also serve as a reference for updating the existing building code of Bangladesh by extending the scope of the study.

Multi-objective optimisation of building design variables is an appropriate and robust approach in assessing office building performance. Conversely, in developing country contexts like Ghana there is lack of credible building design variables from scientific and technical journals. The main research problem was low building performance assessment by building professionals in Ghana resulting in high cooling energy utilization and indoor environmental discomfort within the commercial building sector. Overall, the aim of the research was to use cost effective low energy technologies to optimize the building design variables to achieve recommended good practice for energy utilization of service equipment and indoor environmental performance in office building. Research questions addressed in this research included the following: 1. How does local building professionals’ practices impact on design variables used in performance assessment, and are occupants’ comfortable as well as satisfied with building performance in Ghana? 2. Are the building fabrics used in Ghana suitable for enhancing building performance? 3. How can the building performance design variables from survey questionnaires and experimental assessments be optimized? 4. Are the existing economic benefit assessment tools adequate for fast accurate decision making in comparing recommended good practice for cooling load by CIBSE Guides in hot-humid climate? The following creative and novel methodologies were used for this research: 1. Survey questionnaires using Bristol Online Survey Tool for the administration and acquisition of responses from participants. 2. Experimental assessment of selected fabrics from Ghana and creative parametric fabrics using both TCi Thermal Analyser and AutoPore IV mercury intrusion Porosimeter. 3. Computer simulations for optimised design variables using ESDL Tas. Finally, Design of creative comparator decision making tool for economic benefit assessment of the optimised computer simulations design variables. The selected significant findings from the application of the creative and novel methodologies in addition to the corresponding implications are summarised as follows: 1. An average of 16% of all building professionals do assess design variables associated with its practices with about 60% building professionals satisfied with Ghana building regulations, on the contrary, highly recommended for an improvement on the regulations. 2. Experimental assessment of representative selected Ghana building fabrics and enhanced parametric studies meets the thermo-physical properties outlined in the CIBSE Guide standards, with the range of thermal conductivity being 0.2 to 0.7W/m2K. 3. From the creative computer simulation outcomes, the cooling load of the base case is about 10 times more than the recommended good cooling load practice outlined in CIBSE Guides. The optimised computer simulation single wall layer building design model was achieved using optimum low transmittance building fabrics, optimum internal conditions and low chilled beam technology. 4. From the economic benefit assessment, an increasing trend of inverse correlation between difference in modification cost with cooling load reduction was observed. That is, for reduction in cooling load, there is an increasing cost in modification. For example, for reduction of cooling load of 40% from Case 1 to Case 3, there is a corresponding increase in modification cost of 79.4%. 5. Representative office occupants are generally satisfied and comfortable with building performance in Ghana. The above findings have compounded extreme implications on the local building professionals’ practices, leading to subsequently high cooling load, hence the rising energy utilization of service equipment in non-residential buildings. Finally, the overall aim of achieving the recommended good practice for service equipment energy utilization in commercial buildings was not accomplished for the cooling load. This is due to the difference in cooling load calendar used by CIBSE Guide and hot-humid climate, Ghana. In conclusion, an optimised low cost computer simulation of single wall layer envelope design, with cooling load of 120 kW/m2 for floor area and acceptable indoor environmental quality has been achieved in this research. It is strongly, recommended that, performance assessment should be incorporated into building permit issuing process using the designed creative feedback chart designed in this research.