Development of a mathematical and computer model to assess water quality impacts of hazardous compounds from minor gasoline spills in the inter-tidal zone of the Miami River, Florida

The objective of this study was to develop a model to predict transport and fate of gasoline components of environmental concern in the Miami River by mathematically simulating the movement of dissolved benzene, toluene, xylene (BTX), and methyl-tertiary-butyl ether (MTBE) occurring from minor gasoline spills in the inter-tidal zone of the river. Computer codes were based on mathematical algorithms that acknowledge the role of advective and dispersive physical phenomena along the river and prevailing phase transformations of BTX and MTBE. Phase transformations included volatilization and settling. ^ The model used a finite-difference scheme of steady-state conditions, with a set of numerical equations that was solved by two numerical methods: Gauss-Seidel and Jacobi iterations. A numerical validation process was conducted by comparing the results from both methods with analytical and numerical reference solutions. Since similar trends were achieved after the numerical validation process, it was concluded that the computer codes algorithmically were correct. The Gauss-Seidel iteration yielded at a faster convergence rate than the Jacobi iteration. Hence, the mathematical code was selected to further develop the computer program and software. The model was then analyzed for its sensitivity. It was found that the model was very sensitive to wind speed but not to sediment settling velocity. ^ A computer software was developed with the model code embedded. The software was provided with two major user-friendly visualized forms, one to interface with the database files and the other to execute and present the graphical and tabulated results. For all predicted concentrations of BTX and MTBE, the maximum concentrations were over an order of magnitude lower than current drinking water standards. It should be pointed out, however, that smaller concentrations than the latter reported standards and values, although not harmful to humans, may be very harmful to organisms of the trophic levels of the Miami River ecosystem and associated waters. This computer model can be used for the rapid assessment and management of the effects of minor gasoline spills on inter-tidal riverine water quality. ^

The Ghana National Service Scheme: Perceptions of former educational personnel, students and guardians

The purpose of this inquiry was to investigate the perceptions of former service personnel, students and their parents about the organizational effectiveness of the Ghana National Service Scheme (GNSS). The inquiry addressed the following questions: How do the participants perceive the effectiveness of the national service program on the Ghanaian society? What are the perceptions of school administrators who worked with service personnel, parents and students vis-à-vis the over all impact of the GNSS on the educational system? What are the perceptions of former service personnel, students and their parents in regard to the impact of the GNSS on them? ^ The GNSS is a part within the ministry of education, which is also part in the Ghanaian social structure. Hence, a systems theory approach which asks, “How and why a system as a whole functions as it does” (Patton, 1990), was utilized in the study. Methodologies included purposive sampling; interviews; participant observation, and follow-up interviews. The study was conducted over a six-moth period. ^ A cross-sectional survey design was used to generate data. The survey was followed up with an ethnographic study where in-depth, face-to-face interviews were conducted together with observations. The results were described and interpreted. ^ The summary of findings concludes that perceptional determinants of the effectiveness of the GNSS were biased by the age and zone of origin but not gender. This partially agrees with Marenin's (1990) except for gender. A significant difference was detected between the responses of those who were officials of the National service Secretariat and of former service personnel. The administrators defended the status quo and demonstrated their deeper knowledge about the scheme. The former personnel and parents freely criticized the program when necessary and did not seem to know much about the GNSS. Respondents mostly stressed the need for the secretariat to focus on the following areas: (1) involvement in the agricultural sector of the economy, (2) involvement in rural mass, civic and health education, (3) adequacy of remuneration and personnel welfare, and (4) ensuring posting of personnel to areas of their expertise. Recommendation for further research concluded the study. ^

Characterization of ultra wideband antennas for personal communication devices using finite difference time domain technique

The current mobile networks don't offer sufficient data rates to support multimedia intensive applications in development for multifunctional mobile devices. Ultra wideband (UWB) wireless technology is being considered as the solution to overcome data rate bottlenecks in the current mobile networks. UWB is able to achieve such high data transmission rates because it transmits data over a very large chunk of the frequency spectrum. As currently approved by the U.S. Federal Communication Commission it utilizes 7.5 GHz of spectrum between 3.1 GHz and 10.6 GHz. ^ Successful transmission and reception of information data using UWB wireless technology in mobile devices, requires an antenna that has linear phase, low dispersion and a voltage standing wave ratio (VSWR) ≤ 2 throughout the entire frequency band. Compatibility with an integrated circuit requires an unobtrusive and electrically small design. The previous techniques that have been used to optimize the performance of UWB wireless systems, involve proper design of source pulses for optimal UWB performance. The goal of this work is directed towards the designing of antennas for personal communication devices, with optimal UWB bandwidth performance. Several techniques are proposed for optimal UWB bandwidth performance of the UWB antenna designs in this Ph.D. dissertation. ^ This Ph.D. dissertation presents novel UWB antenna designs for personal communication devices that have been characterized and optimized using the finite difference time domain (FDTD) technique. The antenna designs reported in this research are physically compact, planar for low profile use, with sufficient impedance bandwidth (>20%), antenna input impedance of 50-Ω, and an omni-directional (±1.5 dB) radiation pattern in the operating bandwidth. ^

Angular distribution of prompt photons using the compact muon solenoid detector at a square root of S = 7 TeV

The study of the angular distribution of photon plus jet events in pp collisions at [special characters omitted] = 7 TeV with the Compact Muon Solenoid (CMS) detector is presented. The photon is restricted to the central region of the detector (:η: <1.4442) while the jet is allowed to be present in both central and forward regions of CMS (:η: < 2.4). Dominant backgrounds due to jets fragmenting into neutral mesons are accounted for through the use of a template method that discriminates between signal and background. The angular distribution, :η*:, is defined as the absolute value of the difference in η between the leading photon and leading jet in an event divided by two. The angular distribution ranging from 0–1.4 was examined and compared with next-to-leading order QCD predictions and was found to be in good agreement.