Multi-layer graphene FET compact circuit-level model with temperature effects

This paper presents a circuit-level model of a dual-gate bilayer and four layer graphene field effect transistor (GFET). The model provides an accurate estimation of the conductance at the charge neutrality point (CNP). At the CNP the device has its maximum resistance, at which the model is validated against experimental data of the device off-current for a range of electric fields perpendicular to the channel. The model shows a good agreement for validations carried out at constant and varying temperatures. Using the general Schottky equation, the model estimates the amount of bandgap opening created by the application of an electric field. Also the model shows good agreement when validated against experiment for the channel output conductance against varying gate voltage for both a bilayer and four layer graphene channel

Hybrid sorbent-ultrafiltration systems for the removal of hormones and fluoride from water

The presence of trace contaminants in drinking water resources has been related to adverse health effects in living organisms and humans. Current technologies do not adequately remove these contaminants from water and /or require high energy supply. Exploring low cost, low energy processes in order to eliminate trace contaminants is essential considering that access to clean drinking water and energy is becoming more challenging in many parts of the world. Hormones and fluoride are the two contaminants studied in this research and hybrid systems which combine sorption with low pressure ultrafiltration are proposed for their removal. Sorption is a promising removal mechanism if efficient sorbents and operational conditions are selected, however, the introduction of sorbent materials can cause fouling in ultrafiltration. Fouling reduces the membrane permeability and increases the energy requirement of the system. The overall aim is to study the proposed hybrid sorbent- ultrafiltration systems in terms of contaminant sorption capacity and membrane performance. The systems are tested under varying sorbent size (52 -3000 nm for hormone, <38 -500 μm for fluoride removal) sorbent concentration (1.7 -84 mg /L for hormone, 1 -50 g/L for fluoride removal), sorbate concentration (100 ng /L hormone and 5 -500 mg /L fluoride) and solution pH (3 -12). The thesis can be split into two parts: one part for hormones and the other for fluoride.In the first part, a hybrid polystyrene nanoparticle -ultrafiltration system is investigated for hormone removal. Polystyrene nanoparticles are employed as they provide a large active surface area for the sorption and they can easily be manufactured in different sizes and with various functional groups. The results show that the system can only compete with the existing nanofiltration/reverse osmosis membrane systems if the sorption capacity of the polystyrene nanoparticles is increased. For this reason, carboxyl functionalized polystyrene nanoparticles were also tested. Contrary to expectations, even less hormone sorption is achieved with the functionalized particles. Further investigation of other functional groups such as amine /amidine for their hormone sorption capacity is recommended.In the second part, laterite and bone char are selected as two sorbents for the hybrid sorbent -UF system for fluoride removal as they are locally sourced, low cost materials in parts of Ghana and Tanzania, respectively, where fluoride contamination is a major problem. The sorption capacity and the membrane fouling of the hybrid system with the two selected sorbents are compared. Fluoride sorption capacity of the bone char system is higher than the laterite system and this is attributed to the difference in the available surface area. The fouling of the membranes operated with laterite at high initial fluoride concentrations and alkaline solutions is linked to the precipitation of iron and aluminium complexes. With further system optimization, both hybrid laterite and bone char systems show the potential to be viable solutions for fluoride removal, noting that the bone char system is more feasible for high fluoride concentrations above 10 mg /L. Based on lab scale experimental results, two hybrid laterite -ultrafiltration systems are designed to be tested in Ghana. The two systems, one with submerged hollow fibre and the other with direct dead end tubular ultrafiltration membrane modules, are operated with real surface and ground waters. The findings indicate that the amount of sorption obtained in the field is lower than that which is obtained with laboratory experiments due to the presence of interfering co -ions in the real waters and differences in membrane systems. The systems also show the potential to remove arsenic, uranium and lead. The system with hollow fibre membranes can be suggested as an appropriate system for ground water applications as it did not experience any fouling and the investment cost could be lower compared to the tubular membranes. However, if the surface waters are to be treated with the proposed hybrid system, the tubular membranes offers a system with no fouling. The hybrid laterite -UF system shows to be a promising treatment technology for fluoride contaminated waters in Ghana

UJI DAYA HAMBAT EKSTRAK BIJI KAKAO (THEOBROMA CACAO) TERHADAP PERTUMBUHAN BAKTERI AGGREGATIBACTER ACTINOMYCETEMCOMITANS

ABSTRAKNama : Ime SyahdibrinaFakultas : Kedokteran GigiProgram Studi : Pendidikan Dokter GigiJudul : Uji Daya Hambat Ekstrak Biji Kakao (Theobroma Cacao) terhadapPertumbuhan Bakteri Aggregatibacter actinomycetemcomitansAggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) merupakan salah satu flora normal rongga mulut yang dalam keadaan tertentu dapat menjadi patogen dan menyebabkan periodontitis agresif. Biji kakao (Theobroma cacao) adalah salah satu tanaman yang mengandung senyawa antibakteri seperti flavonoid, tanin, alkaloid, polifenol dan triterpenoid. Tujuan penelitian ini adalah untuk mengetahui daya hambat ekstrak Theobroma cacao terhadap A. actinomycetemcomitans. Ekstrak Theobroma cacao dibuat dengan metode maserasi dalam pelarut etanol 96%. Uji daya hambat ekstrak Theobroma cacao terhadap A. actinomycetemcomitans dilakukan menggunakan metode difusi cakram pada media MHA. Konsentrasi ekstrak yang digunakan adalah 12,5%, 25%, 50%, 75%, dan 100%. Hasil penelitian menunjukkan bahwa pertumbuhan koloni terendah pada konsentrasi 12,5% dengan diameter 4,1 mm dan pertumbuhan koloni tertinggi pada konsentrasi 100% dengan diameter 15,8 mm. Dari penelitian ini dapat disimpulkan bahwa ekstrak Theobroma cacao memiliki daya hambat dengan kategori sedang terhadap Aggregatibacter actinomycetemcomitans menurut klasifikasi Ahn dkk.Kata kunci : Aggregatibacter actinomycetemcomitans, biji Theobroma cacao, antibakterixUniversitas Syiah KualaABSTRACTName : Ime SyahdibrinaFaculty : DentistryStudy Programme : DentistryTitle : Inhibition Test of Cacao (Theobroma cacao) Seeds Extract Against Aggregatibacter actinomycetemcomitans GrowthAggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) is one of normal oral bacteria which in certain circumstances may be pathogens and causes aggressive periodontitis. Theobroma cacao is one of plants which contains antibactial constituents such as flavonoid, tanin, alcaloid, polypheno l and triterphenoid. This study was aimed to determine the antibacterial activity of Theobroma cacao extract against A. actinomycetemcomitans. Theobroma cacaoextract was made by maceration method using 96% ethanol. Inhibition test of Theobroma cacao extract against A. actinomycetemcomitans was done by using diskdifusion method in MHA medium . Concentration of used extract are 12,5%, 25%, 50%, 75%, and 100%. The result of this study showed that the smallest colony growth was at concentration 12,5% with 4,1 mm in diameters dan the greatest colony growth was at concentration 100% with 15,8 mm in diameters. The conclusion from this study was Theobroma cacao extract has medium inhibition capacity against Aggregatibacter actinomycetemcomitans according to Ahn classification.Keywords : Aggregatibacter actinomycetemcomitans, Theobroma cacao, antibacteri

Election Administration and Democratization Process in Nigeria: an Appraisal of 2007-2015

The study analyzed the impact of election administration and Nigeria&rsquo;s democratization process using 2007-2015 general elections as the focal point. The study avers that elections in Nigeria during the period were characterized by various problems, resulting in questionable electoral outcomes. This was largely due to weak political institutions, mainly, the Independent National Election Commission (INEC). INEC lacks financial, institutional and administrative independence, as evidencedby its funding and composition by the presidency, as well as its lack of professional staff and security of tenure for its officials. This study, therefore, critically examines election administration in Nigeria within the periods and how such elections influenceddemocratization process in the Country. In achieving this objective, the study relied on content analysis and adopted abstraction from liberal democratic theory.Elections can only promote and institutionalize democratization in Nigeria if the electoral processes are reviewed in certain ways that fundamentally address the capacity and independence of INEC, to discharge its responsibilities effectively and efficiently. This study revealed that democratization through election administration depends largely on the institutional foundations of the electoral processes, especially, the INEC. A professional, impartial and independent INEC would provide better prospects of effective election administration in Nigeria. This study, however, recommends, among others, that electoral laws should be strengthened to encourage stiff punishment for electoral offenders as well as beneficiaries of fraudulent elections. The study conclude that the trend towards challenging electoral fraud in the courts and the judicial decisions, signal a strengthening of democratic principles and gives some hopes for democratization.&nbsp

Electoral Violence and Democratization Process in Nigeria: A Reference of 2011 and 2015 General Elections

The general account of Nigeria&rsquo;s post-independence electoral processes has always been characterized by violence. Nigeria&rsquo;s 2015 general elections marked the fifth multi-party elections in the country and the second handover of civilian administrations since the inception of the Fourth Republic democratic experiment in 1999. This account cannot be analyzed without issues of electoral violence. Electoral violence had been a permanent feature of Nigeria&rsquo;s democratic process, except 2015 general elections where the international observers described as a &ldquo;significant improvement&rdquo; over the previous elections in terms of violence related cases. Electoral related violence in the country particularly in 2011 got to an unprecedented dimension resulting in destruction of lives and property worth millions of naira. This paper expatiates on electoral violence and its general implications on the democratization process in the country, with major emphasis on the 2011 and 2015 general elections. The paper argued that the high incidence of pre and post electoral violence in the country within the periods has to do with the way Nigerian politicians regard politics, weak political institutions and weak electoral management body as well as bias nature of the security agencies, etc. However, the paper examined the general implications of electoral violence on democratization process and how the country can handle the electoral process to avoid threats associated with the electoral violence. Archival analysis, which widely extracted data from newspapers, journals, workshop papers, books, as well as publications of non-governmental organizations was adopted for the study. The major significance of this study is to expose the negative implications associated with electoral violence and how it can be curbed. The position canvassed in this paper will serve as a useful political literature for political leaders, policy makers and the general reading public who may be seeking general information on the subject matter. The paper therefore, among others, recommended that political leaders and political participants should not see politics as investment or do or die affairs as well as the formulation of laws with severe sanctions against supporters or perpetrators of electoral violence in the country. The paper therefore submits that democratization in the country can only be realistic when the ideals and principles of democracy as practiced in advanced democratic societies are upheld and respected

Personality Development Variables and Academic Cheating Behaviour among Undergraduate Students of the Faculty of Education, University of Uyo, Uyo

This study was a survey of some selected personality development variables on the academic cheating behaviour of undergraduate students in the Faculty of Education, University of Uyo, Uyo. This study was informed by the observation that various attempts to prevent academic cheating have made limited gains. Three independent personality development variables were identified for the study namely gender roles, peer-group pressure and parental pressure. Three research questions and three null hypotheses were formulated to guide the study. The ex-post facto survey design was adopted for the study. Instrument for data collection was the Personality Development Variables and Academic Cheating Behaviour Questionnaire (PTVACBQ) developed by the researcher. The questionnaire was validated by three experts from the Faculty of Education, University of Uyo. The Cronbach’s Alpha reliability estimate of the instrument was 0.84. Data was collected from a randomised sample of 300 undergraduate students selected through the simple random sampling method from a population of over 6000 regular undergraduate students in the Faculty of Education. Data analysis was done with the use of descriptive statistical tools such as mean, percentages, and standard deviation to provide answers to the research questions. To test the null hypotheses, independent t-test and analysis of variance was used. All hypotheses were tested at .05 levels of significance. The result of data analyses show that gender roles, peer-group pressure, and parental pressure significantly influenced academic cheating among the students. Based on these findings, it was recommended that psychoacademic interventions should be put in place within and outside the faculty to assist students overcome dishonest tendencies in their academic work. Keywords: Academic cheating; Personality development; Counselling; Adolescence; Education DOI: 10.7176/RHSS/10-17-06 Publication date:October 31st 202

Undercurrents of Anglo-American Collaboration: Funding, Training and Cold War Influences on the Theatre Studies Curriculum of Selected Nigerian Universities

The Cold War played a crucial but often underestimated role in educational developments across the Third World. In these territories, the drama of decolonisation was often negotiated, scripted, and enacted through a range of initiatives championed by returning students whose activism in politics and academia converged with resistance movements of locally based actors to spur nationalist consciousness, which ultimately led to the triumph of independence across Africa in the 1960s. This paper shall argue that Cold War politics allied with nationalist fervour to engender a deregulation of colonial higher education policies in West Africa, especially in Nigeria. The campaign for access to mass (university) education, the establishment of the University College of Ibadan (UCI) and later its School of Drama, opposition to its British elitist education heritage and the fear of communist infiltration were just some of the things that prompted Anglo-American collaborations in the Nigerian educational system, especially at the tertiary level, via funding, training, and support from institutions such as the Carnegie Corporation and the Rockefeller and Ford Foundations. By examining the curriculum of theatre studies in selected universities in the country, this paper shall advance that not only did sponsorship, funding, and training influence the trajectory of theatre practice and scholarship, but the legacy of colonialism and circulation of experts also played a crucial role in the battle for the future of the practice that manifested not only at Ibadan and Calabar but across theatre departments in most first and second generation institutions in the country

Globalisation and Economic Growth: The Nigerian Experience

International contacts and exchanges are not a new phenomenon. It started from the time of the Mercantilists who were popular from the sixteenth to the middle of the eighteenth century. They traversed the whole world looking for precious metals, in the process partitioned and colonized all parts of the world. Hence, globalization dates back to human history. This was carried out in the form of trade, exchanges, inter country movements, travels and migration. This paper uses descriptive research method to analyze the impact of globalization on economic growth in Nigeria in terms of trade and capital flows. The Nigerian economy was integrated into the global economy before independence. But unfortunately the benefit of globalization did not trickled down to the Nigerian economy as proposed by its proponents. This paper is of the view that increased trade and capital flows engendered by globalization can enhance the country’s growth performance. However, if Nigeria is to benefit from the global integration, it has to address a number of challenges and implement appropriate strategies and policies in order to maximize the benefits of globalization and minimize the risks of destabilization and marginalization, as well as promote rapid economic growth and achieve substantial poverty reduction. Keywords: Impact of globalization, economic growth, trade and capital flows, poverty reduction.

The Extent of Relationship between Stock Market Capitalization and Performance on the Nigerian Economy

This paper examines the extent of relationship between stock market capitalization and performance on the Nigerian economy. Problems identified include the difficulty experienced in raising needed capital to finance key sectors of the Nigerian economy; the stock market is shallow in addition to low activities etc. The objectives included primarily to determine the extent of relationship between stock market capitalization and performance on the Nigerian economy, to access the effect of stock market capitalization and make policy recommendations. Hypothesis tested was that, there is no significant relationship between stock market capitalization and the performance of the Nigerian economy (1988-2008). Data was collected from secondary sources and was analyzed using multiple regression statistics. From the findings, results showed that there is a strong relationship between stock market capitalization and performance on the Nigerian economy with 91 percent (91%) degree of relationship. 1988 was identified as significant, as the year which marks the entrance of equity stocks in the capital market and by 2007, market capitalization hits ?13 trillion. The paper is presented in five sections: - (1) Introduction which includes statement of the problem, Objectives and hypothesis. (2) Brief selected literature review (3) Model and Methodology. (4) Data Presentation, Discussion and Findings.  (5) Conclusion and policy recommendations. The paper concluded that, when the stock market is reasonably traded by public and private sectors with protected legal frameworks, the Nigerian economy will be more expanded for high growth. It was recommended among others, that the Federal Government of Nigeria should set up a stimulus account to boost the stock market and to enforce Degree No. 45 of 1999 for the establishment of the Commodity Exchange Market. Keywords: Stock market, Nigerian Stock Exchange, Market Capitalization, Performance of the Nigerian Economy, Securities.