The function of the construction industry in an economy has proven to be beneficial, especially during the economic downturn. The nature of the products of the construction industry makes it possible for the government to utilise the industry as a means to accelerate and multiply the economy by utilising the fiscal budget to build infrastructures. By so doing, the economy will be multiplied as the construction industry is an industry that produces investment goods. However, due to the nature of the Malaysian construction sector, the expenses required to stimulate the economy could not be made to the maximum extent, as the industry relies heavily on immigrant construction workers to address its labour supply problem. Immigrant construction workers are known for their high tendency to remit their salary to their country of their origin. This scenario disturbs the economic cycle within the Malaysian economy and, hence, dampens the function of the construction industry as the multiplier-accelerator provider. This research was undertaken to better manage the cash flow economic cycle leakage by adopting some economic measures coupled with improvised management of immigrant construction workers exercised through legislation. The adopted research methodology used transformative mixed-methods to balance the limitations of a single research approach. A literature review of the economic models and tools were conducted in a search for the most suitable measures, while attempting to understand the nature of construction industry by highlighting the structure and the problems associated with the industry. Special attention was also given to investigate the motivation behind the human migration to justify and support the research. Other than issues involving the use of immigrant workers, special attention was given to issues of remittances and its impacts on the global economy. The findings underpinned by literature and the research findings were used to develop the conceptual framework to manage the economic cycle leakage that is entrenched in the construction industry s economic cycle. The integrated framework consists of economic, management and legislation and was developed to address the issues highlighted. The use of economic tools can only be materialised through better management and the execution of legislation. The framework was encapsulated in a combination of process protocol and a maturity framework to allow time for the policy makers to implement it. Considerations have been made to develop the framework to ensure the smooth transition its implementation. The framework was self-validated through formative evaluations where data were attained from several parties to reduce any bias perspective. In addition, most of the measures suggested were derived from interviews conducted among the respondents. Several benefits of the framework were identified. It is concluded that the impact of immigrant construction workers employment can be managed by considering the appropriate tools in the form of economic, managerial and legislation measures. This research has developed an integrated process protocol maturity framework that addresses the three aforementioned aspects. The framework is simple and easily understandable with detailed activity zones that entail specific tasks that must implemented by different parties. The developed framework is expected to aid the authorities in managing immigrant construction in Malaysia and to effectively manage these workers. The framework also allows time for its implementation through the maturity stages suggested.

An overview of the beam diagnostics for the laser wakefield acceleration project at the Texas Petawatt Laser facility is presented. In this experiment, short and intense laser pulses of 165 fs and up to 190 J will be used to accelerate electrons up to the GeV energy range using laser wakefield acceleration. The density variation of the plasma generated in a helium gas cell will be measured with different optical detection systems such as frequency domain holography. Spectra of the transmitted laser beam and optical transition radiation will yield information about the energy transfer to the plasma and the energy of the electrons, respectively. In addition, a calorimeter will measure accelerated electron energies. Prior to the final experiment, preliminary frequency shift measurements and simulations on optical transition radiation were performed. / text

No description available.

The goal of this research was to devise a new analytical technique, using Accelerator Mass Spectrometry (AMS), to measure Platinum Group Element (PGE) concentrations to the sup-ppb levels in natural, insulating, samples. The challenges were threefold. First, a method of sputtering an insulating sample to successfully produce a stable beam of anions needed to be devised. Second, a suitable standard of known PGE concentrations had to be found and third, spectral analysis of the beam had to verify any claims of PGE abundance. The first challenge was met by employing a modified high intensity negative ion source flooded with neutral caesium that successfully sputtered insulators to produce a beam of negative ions. The second challenge, that of finding a suitable standard, was fraught with difficulties, as no synthesized standards available were found to be appropriate for this work. As a result, direction is provided for future production of standards by ion implantation. The third challenge, successful spectral analysis, was accomplished using a newly designed gas ionization detector which allowed for resolution of the interfering molecular fragment from the PGE ions. Coupled with the use of the SRIM computer programme, positive identification of all peaks in the spectra of the analyzed samples was accomplished. The success of the first and third challenges lead to the qualitative analyses of geological samples for sub-ppb levels of PGE by AMS. Quantitative analyses await only for the appropriate standards and with those will come a whole new range of research possibilities for measuring sub-ppb levels of PGE in insulating samples by AMS.

The developments of nuclear medicine lead to an increasing demand for the production of radioisotopes with suitable nuclear and chemical properties. Furthermore, from the literature it is evident that the production of radioisotopes using charged-particle accelerators instead of nuclear reactors is gaining increasing popularity. The main advantages of producing medical isotopes with accelerators are carrier free radionuclides of short lived isotopes, improved handling, reduction of the radioactive waste, and lower cost of isotope fabrication. Proton-rich isotopes are the result of nuclear interactions between enriched stable isotopes and energetic protons. An interesting observation is that during the production of proton-rich isotopes, fast and intermediately fast neutrons from nuclear reactions such as (p,xn) are also produced as a by-product in the nuclear reactions. This observation suggests that it is perhaps possible to use these neutrons to activate secondary targets for the production of neutron-rich isotopes. The study of secondary radioisotope production with fast neutrons from (p,xn) reactions using a particle accelerator is the main goal of the research in this thesis.

This thesis will describe the latest work from the Feedback On Nanosecond Timescales project, commonly known as FONT. The goal of the FONT project is the development of a beamline feedback system to be installed at the interaction point (IP) of a future linear collider in order to maximize the luminosity that can be achieved. The prototype FONT feedback system is beam-based, meaning that the correction is determined from direct measurement of the position of the beam, and intra-train, meaning that the correction is applied within the duration of the current bunch train. The FONT system, consisting of three stripline beam position monitors, a digital processor unit built around a Field Programmable Gate Array (FPGA) and a pair of electromagnetic kickers, is described. Recent improvements to the position measurement process are detailed and the performance of the feedback system is presented. The modification of the firmware to operate on a machine with a large number of bunch trains, such as the International Linear Collider, is described and the design is verified through the use of a laboratory test bench developed to simulate such a machine. The FONT5 digital board is proved capable of operating on a train resembling the specification for the International Linear Collider: 2820 bunches separated in time by 308 ns.

The commissioning and development of a laser-wire transverse electron beam profile monitor at the Accelerator Test Facility 2 in Japan is presented. The experimental setup used including a gigawatt laser system is detailed and characterised. Results from data taking in December 2010 are presented detailing the use of the laser-wire to tune the electron beam. In conjunction with this, the use of a fibre-based laser system as a suitable laser source for a laser-wire is discussed. A test bed fibre laser system was constructed to investigate the suitability of fibre lasers and the results are presented demonstrating high efficiency and excellent spatial quality. From this, a laser system capable of high resolution and high repetition intra-train scanning for demonstration at the Accelerator Test Facility 2 was designed, constructed and characterised. A commercial fibre laser system was extended using a photonic crystal fibre where periodic amplification designed to match the duty cycle of an accelerator was used advantageously to achieve higher than normal pulse energies. The results and techniques developed to measure them are presented.

Archaeological bones are usually dated by radiocarbon measurement of extracted collagen. However, low collagen content, contamination from the burial environment or museum conservation work have previously lead to inaccurate results, especially for old bones, compromising the ability to reconstruct reliable past chronologies. It is reported, for example, that up to 70% of Palaeolithic radiocarbon dates on bones are likely to be underestimates of the real age, blurring the picture of modern human dispersals and Neanderthal extinction. In this thesis, a method for isolating and radiocarbon dating the collagen amino acid hydroxyproline is described. Hydroxyproline consists of about 10% of bone collagen but is not found in significant amounts elsewhere in nature. The hydroxyproline dating method uses a mixed-mode (i.e. ion-exchange combined with hydrophobic chemistry), semi preparative HPLC methodology. The amino acids do not require derivatisation, and no organic solvents are used, thereby avoiding addition of carbon. The hypothesis of this thesis is that the hydroxyproline can be used as a bone specific biomarker, improving dating accuracy and making it possible to obtain radiocarbon determinations where previously it has been impossible. It was calculated that on average 3.3±1.4μg of contaminant carbon are added to each sample in the process of isolating the hydroxyproline, a low level suitable for 14C dating. It was investigated whether a deliberately contaminated bone and 'naturally' contaminated archaeological bones, yielding erroneous dates when dated using the normal pretreatment method, could be dated accurately using this method. In addition, a hydroxyproline date was obtained for a bone with too little surviving collagen to be dateable by the bulk collagen method. Finally, using the hydroxyproline dating method, the earliest direct ages for the presence of anatomically modern humans on the Russian Plain were obtained. The method proved to be a powerful tool that can help resolve longstanding archaeological questions.

The use of Mineral Trioxide Aggregate (MTA) is gaining popularity among clinicians. Despite the many ideal qualities it possesses, it is often difficult to manipulate and often requires a second appointment for placement of a restoration to allow for setting. If the time to set of MTA can be accelerated to a single appointment time frame without significantly altering its properties, then MTA may gain even wider acceptance. The purpose of this study is to identify the percentage of a Portland Cement Accelerator (PCA), that when added to MTA, will decrease the time to set of MTA towards a single appointment time frame. Ten Teflon sample molds were prepared to hold 20 standardized chambers in each. Three sample molds were prepared with a 5.0% (by weight of MTA) accelerator, 3 with 10.0% accelerator and 3 with 15.0% accelerator mixed with MTA and water. Another sample mold contained a mixture of MTA and water only and acted as the control. Samples were tested using a dial indicator microgauge apparatus that measured the depth of needle penetration starting at 2 minutes and then every minute up to 15 minutes. Samples were also tested at 3, 4, 24, 48 and 72 hours. A mixed-model repeated measures ANOVA showed the four accelerator groups were significantly different and there was a significant time trend. The 5.0% accelerator group set significantly faster compared to the 15.0% and the control at 15 minutes or less (p<0.05). In conclusion, it appears that 5.0% PCA when added to MTA can accelerate the setting reaction.

Particle accelerators produce beams of high-energy particles, which are used for both fundamental and applied scientific research and are critical to the development of accelerator driven sub-critical reactor systems. An effective magnetic shield is very important to achieve higher quality factor (Qo) of the cryomodule of a particle accelerator. The allowed value of field inside the cavity due to all external fields (particularly the Earth’s magnetic field) is ~15 mG or less. The goal of this PhD dissertation is to comprehensively study the magnetic properties of commonly used magnetic shielding materials at both cryogenic and room temperatures. This knowledge can be used for the enhanced design of magnetic shields of cryomodes (CM) in particle accelerators. To this end, we first studied the temperature dependent magnetization behavior (M-H curves) of Amumetal and A4K under different annealing and deformation conditions. This characterized the effect of stress or deformation induced during the manufacturing processes and subsequent restoration of high permeability with appropriate heat treatment. Next, an energy based stochastic model for temperature dependent anhysteretic magnetization behavior of ferromagnetic materials was proposed and benchmarked against experimental data. We show that this model is able to simulate and explain the magnetic behavior of as rolled, deformed and annealed amumetal and A4K over a large range of temperatures. The experimental results for permeability are then used in a finite element model (FEM) in COMSOL to evaluate the shielding effectiveness of multiple shield designs at room temperature as well as cryogenic temperature. This work could serve as a guideline for future design, development and fabrication of magnetic shields of CMs.