Breakdown and recovery of thin gate oxides

Breakdown events are studied in varying test set-ups with a high time resolution. Often a partial recovery from breakdown is observed\ud within a few ms. Parameters such as device area, stress conditions and parasitic elements prohibit the recovery if they result in a high system impedance. The results suggest the existence of a highly conductive path that can be annihilated during breakdown

Notes on the cytogenetics of some South African Xiphinema species (Nematoda: Longidoridae)

The cytogenetics of several South African species of Xiphinemawere studied and compared with the existing data for this genus from Europe. The process of oogenesis appears to be very similar in all species studied, with little interspecific and intraspecific differences. The ovaries of the South African specimens are larger, with more oogonia and oocytes. The chromosomes are also relatively larger, but could not be counted in oocytes during diakinesis, which usually represents the best stage. Chromosome numbers were therefore determined in the oogonia, which yielded quite accurate and consistent results. The diploid number of 10 seems to be constant in all species studied, but differs from one species of the X. americanum group, for which a number of five has been reportedy Polyploids were not encountered in any of the South African specimens

A traffic congestion management plan for Gauteng?

Paper presented at the 32nd Annual Southern African Transport Conference 8-11 July 2013 "Transport and Sustainable Infrastructure", CSIR International Convention Centre, Pretoria, South Africa.With traffic congestion acknowledged to be a major problem in our cities, much thought has been given to ways of managing it. It is neither desirable to focus on a sectoral approach to implementing congestion management measures; nor is it sustainable to implement a variety of Transport Demand Management (TDM); Transport Supply Management (TSM); and Land-Use Management (LUM) measures, on a piecemeal basis. To overcome the strictly sectoral application of such measures, Integrated Development Plans (IDPs) have the scope to integrate supply, demand and land-use management measures, as they have a strategic position within regional planning that coordinates and aligns many sectoral functions at local and district level. This paper highlights the need for the development of a Traffic Congestion Management Plan (TCMP) as a component of the South African planning system’s delivering balanced packages of measures. It also considers a TCMP’s likely structure, and examines the way in which to focus sectoral integration and alignment more directly in the management of traffic congestion in a sustainable manner.This paper was transferred from the original CD ROM created for this conference. The material was published using Adobe Acrobat 10.1.0 Technology. The original CD ROM was produced by Document Transformation Technologies Postal Address: PO Box 560 Irene 0062 South Africa. Tel.: +27 12 667 2074 Fax: +27 12 667 2766 E-mail: nigel@doctech URL: http://www.doctech.co.zamv201

Utilization of Fly Ash in Road Construction in South Africa: Environmental Assessment

Published Conference ProceedingUsing fly ash as alterative material in place of conventional materials is continually gaining interest over decades. This results from its international recognition as non-hazardous construction material. However, fly ash composition varies and thus it cannot be generalized that every fly ash is non-hazardous. In South Africa, fly ash is produced in large quantity, yet its utilization on annual basis remains at 6 percent which is majorly utilized in cement and concrete production. Thus, this study focuses on investigating leaching of major elements in South Africa Class F fly ash when used as a stabilizer in road construction. Three different specimens of fly ashes, namely; Kendal Dump Ash, Durapozz and Pozzfill enhanced with different cements were used as stabilizer for G5 soil use in road construction. Using an X-Ray spectrometry analyser the samples were tested for any possible leach elements. Leach tests results show that fly ash enhanced with cement as soil stabilizer in road construction is not harmful as the fly ash constituents‘ exhibit limited mobility. However, results also indicated that fly ash left in dump sites can be harmful, if some of the leached elements find their way to the ground water. Thus, utilization of fly ash for road construction is an environmental sustainable option and has engineering advantages when properly used for soil stabilization

PRASA : joining demand forecasting and the technology choice framework

Paper presented at the 33rd Annual Southern African Transport Conference 7-10 July 2014 "Leading Transport into the Future", CSIR International Convention Centre, Pretoria, South Africa.The Passenger Rail Agency of South Africa (PRASA) completed the update and reissue of its National Strategic Plan in 2012. As part of this process PRASA recognised that its classic offering of high capacity heavy rail services was not appropriate for all corridors, and that alternative modes may offer more suitable capability. Analysis of a large range of comparator systems across the world was undertaken to determine the key characteristics of a range of rail and road based transport modes. The findings adapted to South African conditions and presented in a tabular format. This Technology Choice Framework was used to inform stakeholders as to the options PRASA could offer. PRASA used this framework to analyse each corridor. Evidence is presented describing this analysis in Kwa-Zulu Natal (KZN), and the conclusion that Light Rail Transport (LRT) would provide a better option for the longer term for the lesser used corridors. Building on this core vision a concept has been developed for a wider network that serves the city centre, and creates urban redevelopment opportunities in the city centre and harbour area following the transfer of port activity further west. This is an example of PRASA’s approach, worked up in conjunction with local stakeholders, to determine future development options appropriate to local needs, and through objective assessment of the most suitable transport technology.This paper was transferred from the original CD ROM created for this conference. The material was published using Adobe Acrobat 10.1.0 Technology. The original CD ROM was produced by CE Projects cc. Postal Address: PO Box 560 Irene 0062 South Africa. Tel.: +27 12 667 2074 Fax: +27 12 667 2766 E-mail: [email protected]

Optimisation of tower site locations for camera-based wildfire detection systems

Early forest fire detection can effectively be achieved by systems of specialised tower-mounted cameras. With the aim of maximising system visibility of smoke above a prescribed region, the process of selecting multiple tower sites from a large number of potential site locations is a complex combinatorial optimisation problem. Historically, these systems have been planned by foresters and locals with intimate knowledge of the terrain rather than by computational optimisation tools. When entering vast new territories, however, such knowledge and expertise may not be available to system planners. A tower site-selection optimisation framework that may be used in such circumstances is described in this paper. Metaheuristics are used to determine candidate site layouts for an area in the Nelspruit region in South Africa currently monitored by the ForestWatch detection system. Visibility cover superior to that of the existing system in the region is achieved and obtained in several days, whereas traditional approaches normally require months of speculation and planning. Following the results presented here, the optimisation framework is earmarked for use in future ForestWatch system planning

Prasa: Delivering the national strategic plan.

Paper presented at the 32nd Annual Southern African Transport Conference 8-11 July 2013 "Transport and Sustainable Infrastructure", CSIR International Convention Centre, Pretoria, South Africa.The Passenger Rail Agency of South Africa (PRASA) has recently completed the update and reissue of its National Strategic Plan. The Plan presents a transformational, integrated and holistic approach to developing rail and long-distance bus services in South Africa which would provide an improved, integrated and effective service to the travelling public over the next forty years. It was developed through significant stakeholder-engagement and was designed to support stakeholders’ development objectives. Innovative approaches to timetabling services which would relieve crowding and reduce journey times are adopted, so as to maximise the benefits from forthcoming major PRASA investment. Innovative interventions were developed, including light rail, to regenerate a city centre and new major rail corridors. The Plan lists specific priorities for change and investment along each of the nation’s rail corridors, enabling the achievement of a future strategic vision for PRASA. From the earliest stages of the development of the Plan, there has been a strong focus on identifying organisational measures which would facilitate its delivery. This paper outlines the approach taken, and the resulting main issues, outcomes and priorities of the Plan.This paper was transferred from the original CD ROM created for this conference. The material was published using Adobe Acrobat 10.1.0 Technology. The original CD ROM was produced by Document Transformation Technologies Postal Address: PO Box 560 Irene 0062 South Africa. Tel.: +27 12 667 2074 Fax: +27 12 667 2766 E-mail: nigel@doctech URL: http://www.doctech.co.zamv201

Decision support for the selection of optimal tower site locations for early-warning wildfire detection systems in South Africa

Effective early detection of forest fires can be achieved by specialised systems of tower-mounted cameras. Foresters and locals with intimate knowledge of the terrain traditionally plan the tower site locations – without the aid of computational optimisation tools. However, such knowledge and expertise may not be available to system planners when entering vast new territories. The process of selecting multiple tower sites from a large number of potential site locations with the aim of maximising system visibility of smoke above a prescribed region is a complex combinatorial optimisation problem. We present two recent applications of novel site-selection frameworks for tower-mounted camera-based wildfire detection systems (CWDS), which have been under development with guidance from experts from the South African developed ForestWatch wildfire detection system. A novel single-site search framework determined alternatives for 13 proposed sites in South Africa's Mpumalanga province, of which 6 alternatives were chosen over the initially proposed sites. The system site selection framework was showcased in determining a four-camera CWDS layout in South Africa's Southern Cape – significantly improving on the detection capability of the layout initially proposed by technical experts