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The dissociative ionization by electron impact of H₂, H₂O, and H₂S was investigated between the electron impact energies of 20 and 45 eV. Protons were the detected fragments, and a time-of-flight method was used to measure the proton kinetic energies. By also measuring the thresholds for the production of discrete energy groups of protons, it was possible to determine the dissociation limits and kinetic energy distributions for individual electronic states. It was found that autoionizing states that lead to dissociation were the major contributors of proton fragments for all of the molecules investigated. Some of the measurements are tabulated in the following table. (UNFORMATTED TABLE FOLLOWS) Molecule Threshold Dissociation Probable Probable (eV) limit (eV) state fragments H₂ 24.5±1.0 18.0±1.0 Q₁ ¹Σ(g)⁺ H⁺, H(1S) 30.5±1.0 18.0±1.0 Q₁ ¹Πᵤ H⁺, H(1S) 36.5±1.0 -- ²Πᵤ H⁺, H(2P) H₂O 24.5±1.0 19.5±1.0 -- H⁺, OH (X²Π) 29.5±1.0 23.0±1.0 -- H⁺,O(³P),H(1S) H₂S 25.5±1.0 18.0±1.0 -- H⁺, HS (X²Π) 32.0±1.0 -- -- H⁺, . . . 42.0±1.0 -- -- H⁺, . . . (TABLE ENDS)

L’objet de ce travail est de voir si les régions les plus concentrées sont les plus compétitives. On va analyser la distribution et la concentration géographique et économique de la population, de l’emploi et des entreprises à travers le territoire tunisien pour ensuite passer à l’étude de l’état de la compétitivité à différents niveaux et en prenant le cas des régions tunisiennes comme référence. Pour se faire nous avons usé, dans une première partie, d’un ensemble d’indices absolu et relatifs qui nous ont permis de découvrir l’état de la concentration au niveau nationale et régional pour après appliquer la méthode d’analyse structurelle résiduelle (ASR) afin de comprendre si l’évolution des schémas d’implantations de l’emploi et des entreprises est le fruit de facteurs propres aux secteurs ou au contraire relatifs à l’environnement. Une deuxième partie dans laquelle, nous avons use d’un ensemble d’indicateurs et déterminants pour appréhender la compétitivité qu’elle soit macroéconomique et mésoéconomique. Ensuite, nous avons essayé de déterminer l’état de développement de la compétitivité ainsi que les avantages qui font la dynamique économique pour les différentes régions tunisiennes. Globalement, on a conclu que les régions les plus concentrées en Tunisie sont les plus compétitives. Ainsi, il existe un déséquilibre que ce soit en matière de concentration des populations, de l’emploi et des entreprises entre les régions du littoral et celles de l’intérieur. Ce déséquilibre est palpable aussi en matière de compétitivité entre ces différentes régions. / The purpose of this work is to see, if the more concentrated regions are more competitive. We will analyze the distribution and geographic concentration and economic population, employment and businesses across the Tunisian territory before moving on to the study of the state of competitiveness at different levels and taking the case of Tunisian regions as reference. To do this we use, in a first part, a set absolute and relative indices that have allowed us to discover the state of the concentration at national and regional levels to implement the following method of structural analysis residual (ASR) to understand whether the changing patterns of employment offices and businesses is the result of factors specific to sectors or otherwise relating to the environment. A second part, in which, we used a set of indicators and determinants to understand the macroeconomic and mesoeconomic competitiveness. Then, we tried to determine the status of the development of competitiveness and the benefits are economic dynamics for different regions of Tunisia. Overall, it was concluded that the most concentrated areas in Tunisia are the most competitive. Thus, there is an imbalance whatsoever regarding concentration of population, employment and business between the coastal regions and those inside. This imbalance is also palpable in competitiveness between these regions.

Faculty of Humanities School of Literature and Language Studies 8703354e kate.skinner@mweb.co.za / The dissertation tracks the media development and diversity policy positions of the South African government with a particular focus on the establishment of the Media Development and Diversity Agency. It tracks the reasons for the reduction in the Agency’s funding and the curtailing of its mandate. The dissertation argues that a powerful coalition of forces including the commercial media sector and the Department of Finance (now National Treasury) impacted on the policy process to drive government thinking in a more market-driven direction. It explores the implications of this market thinking for the deepening of media development and diversity in the country. Further, the research looks at an alternative critical political economy of the media vision – firstly, in terms of how this vision was scuppered in the policy process, but also how it might be resurrected. The critical political economy of the media school argues that development and diversity issues are not unproblematically served by the market and commercially driven media systems. Critical political economists of the media call for a number of state intervention including anti-monopoly legislation, subsidies for struggling more marginalised media sectors and so forth. Also, they call for the development of a core non-commodified, citizenship-orientated and inclusive public service media sector.

A microfluidic device, based on electrophoretic transport and electrostatic trapping of charged particles, has been developed for continuous capture and concentration of microorganisms from water. A generic design, utilizing mobility and zeta potential measurements of various microorganisms exposed to different environmental conditions and physiological states, was employed. Water and buffer samples at pH values ranging from 5.2–7.0 were seeded with bacteria (E. coli, Salmonella, and Pseudomonas) and viruses (MS-2 and Echovirus). Negative control and capture experiments were performed simultaneously using two identical devices. Both culture based methods and real-time PCR analysis were utilized to characterize the capture efficiency as a function of time, flowrate, and applied electric field. Based on differences between the capture and negative control data, capture efficiencies of 90% to 99% are reported for E. coli, Salmonella, Pseudomonas, and MS-2, while the capture efficiency for Echovirus was around 75%. Overall, the device exhibits 16.67 fold sample volume reduction within an hour at 6 mL/hr. This results in a concentration factor of 15 at 90% capture efficiency. Direct quantification of capture on the anode of the prototype microfluidic device was also performed by particle tracking using fluorescent microscopy. Based on image processing, the capture data at different locations on the electrode surface is quantified as a function of the wall shear stress at these locations, which is calculated using CFD simulations. Finally, the Faradaic processes in the microchannel due to electrochemical reactions are studied to predict the amount of electrophoresis in the system. Scaling of the device to sample 5 L/hr can be achieved by stacking 835 identical microchannels. Power and wetted volume for the prototype and scaled devices are presented. The device can thus function either as a filtration unit or as a sample concentrator to enable the application of real-time detection sensor technologies. The ability to continuously sample water without chemical additives facilitates the use of this device in drinking water distribution systems. This work constitutes the first step in our development of a continuous, microbial capture and concentration system from large volumes of potable water.

A microfluidic device, based on electrophoretic transport and electrostatic trapping of charged particles, has been developed for continuous capture and concentration of microorganisms from water. A generic design, utilizing mobility and zeta potential measurements of various microorganisms exposed to different environmental conditions and physiological states, was employed. Water and buffer samples at pH values ranging from 5.2–7.0 were seeded with bacteria (E. coli, Salmonella, and Pseudomonas) and viruses (MS-2 and Echovirus). Negative control and capture experiments were performed simultaneously using two identical devices. Both culture based methods and real-time PCR analysis were utilized to characterize the capture efficiency as a function of time, flowrate, and applied electric field. Based on differences between the capture and negative control data, capture efficiencies of 90% to 99% are reported for E. coli, Salmonella, Pseudomonas, and MS-2, while the capture efficiency for Echovirus was around 75%. Overall, the device exhibits 16.67 fold sample volume reduction within an hour at 6 mL/hr. This results in a concentration factor of 15 at 90% capture efficiency. Direct quantification of capture on the anode of the prototype microfluidic device was also performed by particle tracking using fluorescent microscopy. Based on image processing, the capture data at different locations on the electrode surface is quantified as a function of the wall shear stress at these locations, which is calculated using CFD simulations. Finally, the Faradaic processes in the microchannel due to electrochemical reactions are studied to predict the amount of electrophoresis in the system. Scaling of the device to sample 5 L/hr can be achieved by stacking 835 identical microchannels. Power and wetted volume for the prototype and scaled devices are presented. The device can thus function either as a filtration unit or as a sample concentrator to enable the application of real-time detection sensor technologies. The ability to continuously sample water without chemical additives facilitates the use of this device in drinking water distribution systems. This work constitutes the first step in our development of a continuous, microbial capture and concentration system from large volumes of potable water.

The performance of a Direct Methanol Fuel Cell has been experiment and analysis in this research. The performance of Direct Methanol Fuel Cell were tested by changing different parameter, such as methanol concentration, temperature, and the effect of carbon dioxide. This influence include transient and steady-state respond. Through the experiment and analysis, we hope we could understand the important factors which influence the performance of the DMFC. This experiment use Nafion® as membrane electrode assembly, and the ratio of flow channel area to total electrode area is 58%. The performance of the single cell was enhanced by increasing methanol concentration as the experiment result, no matter transient or steady-state respond. The best performance was obtained from 2M. The performance at transient or steady-state was also improved by increasing methanol/cell temperature. The product of the reaction, carbon dioxide, will cause more influence when cell work at higher current. In addition, there are few carbon dioxide which will appear as gaseous state.

The method of C-V analysis is a powerful technique to determine the parameter of MOS (metal oxide semiconductor) structure. In this study, we fabricate the MOS structure with rf magnetron sputtering of Ta2O5 on n-ZnSe surface. The n-ZnSe¡¦s with various carrier concentrations have different electrical property. Interfaces of various Ta2O5/ZnSe have different properties, for examples flatband voltage, threshold voltage, the mobile oxide charge density, and the effective oxide charge concentration and etc. We find that the interfaces of the Ta2O5/ZnSe MOS structure have low mobile charges and interface trap charges. Thus Ta2O5/ZnSe MOS structure may be worthy to develop further.

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