Discussion on the figures of merit of identified traps located in the Si film : surface versus volume trap densities

The aim of this work is a discussion on the figures of merit of identified traps located in the depletion zone (Si film) of advanced MOSFET devices. Two methodologies to estimate the volume trap densities are investigated, one using the relationship between the surface trap density and volume trap density and a second one based on the temperature evolution at fixed frequency of the generation-recombination plateau level associated to the same trap. By comparing the volume trap densities estimated using these two methods, the results are not agreeing with each other, suggesting that these methods can no longer be used with accuracy in multigate devices. Moreover, they may lead in certain cases to results physically not correct. Even about of the volume defects, the linear evolution between the plateau and the characteristic frequency of the generation-recombination contributions associated to the same trap give us the surface trap density without any additional assumption

An appraisal study of language usage and use for literacy in second language acquisition: An investigation into English textbooks used in the Democratic Republic of Congo

Philosophiae Doctor - PhDSince a number of studies on textbooks in Second Language Acquisition (SLA) have shown that textbooks hold a major place in education (De Guzman, 2000; Oakes & Saunders, 2004), this study proposes to investigate the content of an English Language Teaching (ELT)/ English as a Second Language (ESL) textbook used in 6th form secondary school (Grade 12) in the DRC, Go for English 1RE. It aims to identify and evaluate the content of this ELT textbook so as to deduce and derive main insights for the determination or not of its appropriateness and relevance in terms of its contribution to language use and literacy in the ELT/ESL curriculum of the DRC. The study draws its theoretical underpinning from two theories: the Cunningsworth’s textbook analysis theory and McDonough and Shaw evaluation theory. As research design, the study adopts an a descriptive, exploratory and interpretive design which draws on both quantitative and qualitative data collected on the basis of textbook evaluation checklist and semi-structured interviews. In regard to the procedural orientation, the study uses descriptive and content analysis to analyze, interpret and examine both interviews and textbook evaluation likert-scale checklist data. In respect of its data, the study uses ‘mixed methods approach’. Both qualitative and quantitative data come from 259 teacher and student participants on the basis of two different samples. The quantitative data comes from 209 student participants and 25 teacher participants and the qualitative data from 10 student participants and 15 teacher participants. The findings attest to the general content of "Go for English 1RE ELT" textbook in regard to language activities and tasks related to its subject matter, to the quality and nature of language it contains, and finally to the diversity in its subject matter and its cultural aspects, is suitable for language use and literacy skills development. However, even though its content is suitable, the findings also indicate that this ELT textbook is not well adapted to Congolese 6th form secondary school students’ level

Transforming and Interpreting the Kasbah: The Negotiation of Centrality in Tunis

The kasbah has been considered the main place of power in Tunis since the Middle Ages. Its urban structure was stabilised during the Ottoman era. Since then, the governmental functions of the kasbah have always been confirmed: many ministerial functions are carried out in the buildings around its central square, located at the top of the old city of Tunis. This space is perceived as morphologically separate from the medina and functionally dedicated to issues related to the central sphere. This contrasts with the space of the medina, which was historically regulated by the local civic sphere. In spite of this apparent opposition of functions, the purpose of this study is to reflect on the nature of the kasbah as a public place, as a monumental and architectural expression of a negotiated form of power and centrality, and finally, yet importantly, as an urban district participating in ordering the medina. It is where local urban functions such as markets and mosques were located. It structured the civic dimension embodied by the Beldis, a group of urban notables entrusted with most responsibilities in local institutions as professions (guilds, markets, trade), confessional communities, neighbourhoods, and the city as a whole. In contrast with interpretations based on a dichotomic vision of urban morphologies and functions, the aim here is to highlight the intertwining of spaces and the importance of connections between political and commercial centralities in everyday practices, an angle of interpretation that invites nuance into discussions on the nature of centrality

The Burden of Birth: Racialized Margins of Care in Washington, D.C.

The United States has shockingly high rates of maternal mortality in which Black women bear a disproportionate burden of pregnancy related deaths. In D.C., the nation\u27s capital, Black women account for 90% of pregnancy associated deaths, despite comprising less than half of the population. This disparity is a result of systemic medical racism, geographical barriers, and a lack of available culturally reverent care. Community-based collectives have emerged to fill in the gaps left by the healthcare system by providing essential services to underserved communities, specifically Black women. These organizations have proven the potential of ‘non-traditional’ healthcare models to change the landscape of maternal health both in D.C. and the U.S. By centering care around the specific needs of Black mothers, these collectives have been able to offer more personalized and culturally relevant services, including access to midwives, birth trainings, and mental health support. These initiatives exemplify the power and strength of grassroots efforts in changing health outcomes, providing medical care, education, advocacy, and supporting expecting mothers in any way they may need. This essay will outline the specific historical and systemic factors influencing current maternal mortality rates amongst Black women in D.C. and will demonstrate the efficacy of culturally congruent care as a solution to this crisis

Sexual Violence Beyond the War: Dismantling and Addressing Domestic Violence in the Democratic Republic of Congo

This thesis analyzes the issue of domestic violence in the Democratic Republic of Congo that is often overlooked due to the prevalence and coverage of war-­‐related sexual violence. This paper aims to analyze the many factors that have made domestic violence so prevalent in the African region, followed by the factors unique to post-­‐conflict DRC. Furthermore, it will be evaluating the services currently provided by local and national NGOs as well as other external actors and examine whether they address or have the potential to address issues of domestic violence. Lastly, programmatic and policy recommendations for addressing domestic violence will be drawn from an examination of best practices from current interventions. The objective is for this analysis to inform future remedies for domestic violence in the DRC that do not only treat “symptoms” but also address root causes of violence against women to ensure that interventions are strategic, targeted and that change is sustainable

Passive treatment of acid mine drainage using South African coal fly ash in a column reactor

Thesis (MEng (Chemical Engineering))--Cape Peninsula University of Technology, 2020Fly ash (FA) and acid mine drainage (AMD) are two undesirable materials generated from combustion of pulverized coal for energy and mining activity respectively. Both waste materials have serious, negative impacts on the environment. Fly ash storage leaches a variety of contaminants into surface and groundwater and AMD contains high amounts of toxic metals besides the already dominant !"# concentrations. Many studies had investigated AMD treatment using FA and successfully removed significant amounts of sulphate, as well as minor and trace elements. Hence AMD can be treated using coal fly ash in an active or passive system without addition of any other chemicals. This study had as of objectives the evaluation of the neutralization capacity of FA from two South African’s power stations located in Mpumalanga which are Lethabo and Kendal with mine drainage water from the Mpumalanga coal fields using passive treatment. The research program simulated ex-situ neutralization of AMD in a fly ash slurry followed by continued AMD contact, representing the potential for using spent material as mine annulus fill to reduce air and water content and further AMD generation. Both the fly ash and AMD were obtained from the Mpumalanga province in Eastern South Africa. A 3:1 slurry ratio of AMD to fly ash was mixed until pH stabilized. After mixing, the slurry was packed in columns and left for a duration of 24 hours for a good settling time before the hydraulic treatment. Thereafter the AMD was continuously passed through the columns using gravity flow. Samples of effluent were collected at set time intervals during the hydraulic treatment. These samples were used to determine the flow rate, pH of the leachates and some sent for analysis by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and Ion Chromatography (IC) to determine the composition of the effluent water recovered. The X-ray diffraction done on both coal fly ash sources shown a dominance of quartz and mullites,on the other hand the X-ray fluorescence demonstrate that Kendal and Lethabo coal fly ash belong to class F ash due to fact that the total composition of SiO2, Al2O3 and Fe2O3 was exceeding 70% of the entire composition. Moreover, trace elements such as As, V, Ni, Mn, S, Sr, Cu, Y and Pb are found in the CFA used as well. The ICP-OES analysis showed that Eyethu AMD is very acidic with a pH of 2.23, with sulphate concentration of 2680 mg/L, displaying the existence of some metals some of which are Ca, Al and Fe. The neutralization process of Eyethu acid mine drainage using Kendal and Lethabo CFA was highlighted by the variation of pH from the time mine water was in contact with CFA, for the treatment with Lethabo CFA the treated water had its pH raised from 2.23 to 12.65 and from 2.23 to 8.37 using Lethabo and Kendal CFA respectively and this phenomena was explained by the dissolution and hydrolysis of the oxide components such as CaO. This neutralization process was characterized by a strong buffer zone around the pH of 12.83 to 8.37 from the Lethabo leachate and between 8.37 to 7.28 for the leachate from Kendal column. This buffer zone is explained by the hydrolysis of Al3+ which forms a hydroxide phase until all the aluminum ion was totally hydrolyzed. Electrical conductivity was also observed to vary. An amount of 1440 g of Kendal fly ash was used in the columns and treated 15 bed volumes of Eyethu AMD before the CFA was exhausted and lost its neutralizing power in the case of Lethabo CFA, 13 bed volumes of AMD were treated with 1280g CFA before breakthrough was observed. During treatment of Eyethu AMD with Lethabo and Kendal CFA the flow rate of the effluents water first increased during the first minutes of contact of AMD with CFA then started decreasing with time. The concentration of sulphate was reduced to up to 88% in the effluent from Lethabo CFA and 56% in the effluent from Kendal CFA. Some other metals such Fe, Mg, Mn, Al have been significantly removed from the AMD in the Lethabo and Kendal leachate. Furthermore, mass balance calculation were done around the columns in order to determine the moisture content and the % water recovery. From the calculation done it was shown that the column made of Kendal CFA can treat the AMD with a water recovery of 91.9% while Lethabo column could only recover 83.33% of the inlet water. In addition, Acid Base accounting tests were done in order to determine whether either Kendal or Lethabo CFA are from an acid generating or neutralizing rock. Test results have shown that both Kendal and Lethabo CFA are from an alkaline producing rock as their Net Neutralizing Potential and Neutralizing Potential Ratio were above 20 Kg/t CaCO3

Ballistic Limit Estimation Approaches for Ballistic Resistance Assessment

The armour technologist conducts ballistic impact testing either for evaluating armour materials and systems or for studying material’s defeating mechanism. Most standards make use of the ballistic limit velocity for ballistic assessment. This is the bullet impact velocity that leads to the protection perforation in 50 per cent of the cases. Various models have been emerged to estimate this key metric. The present article summarises the popular models developed for ballistic limit estimation. An attempt is made to point out models’ strength and weakness. First, the experimental set-up used for that goal is displayed. Next, a concise overview of ballistic limit estimation methods is presented. Lastly, a discussion is dedicated to model’s comparison and analysis. This literature survey reveals that the main drawback of already existing methods is that they are purely statistical. Moreover, existing methods are based on the normality assumption of perforation velocities which tends from -infinity to infinity. The main conclusion of this survey is that the presented methods offer a comparable accuracy in estimating the ballistic limit velocity. However, a given variability is remarked when extreme values estimation is of interest, impact velocities leading to low and high perforation probability. Finally, existing models’ performances decay with the reduction of the experimental sample size which represent a constraining requirement in ballistic resistance assessment