yacob gebreyohannes
229234035
Hourly Solar Radiation Estimation Using DM and GRNN Models
Yacob Gebreyohannes
233577179
Temporal and spatial solar resource variation by analysis of measured irradiance in Geba catchment, North Ethiopia
Abstract The availability of solar energy resource information in Ethiopia is limited due to the lack of ground measurement stations. The aim of this work was, therefore, to estimate the temporal variation and spatial distribution of solar radiation for Geba catchment located in the Northern part of Ethiopia based on four selected measurement sites. To achieve this, ground measurement data at ten minute interval that has been recorded for five years was employed. Time series data and temporal variation analysis were done for all the sites. The spatial distribution analysis was carried out by interpolation of the data from the sites across the catchment using Inverse Distance Weight (IDW) method of the ArcGIS software. The temporal data analysis indicated higher solar radiation of greater than 5 kWh/m2/day during the dry months of September to May and in the range of 3 4 kWh/m2/day during the rainy season of June to August. The result of the analysis on spatial distribution of solar radiation showed 5% 7.5% variation with daily average solar radiation of 5.6 kWh/m2/day across the catchment. Areas in central part around Mekelle and southern part around Mayderhu site have relatively higher solar radiation.
Mulu Bayray Yacob Gebreyohannes Hailay Gebrehiwot Solomon Gebre Teklemichael Anwar Mustefa Asfafaw Haileslassie Petros Gebray Ashenafi Kebedom Fana Filli
199188158
Ray Tracing Study for Optical Characterization of Solar Concentrator Reflecting Materials
Various solar concentrators have been widely used to direct the beam solar radiation on to the absorbing surface. The performance of solar concentrators depends on the distribution and intensity of the reflected radiation. This research aims at investigating the performance of the easily available and cost effective glass mirror and aluminum foil reflectors. Simsun target ray tracing software was employed to model and simulate the interaction of the radiation reflecting materials for the establishment of parameters that allow the most suitable type and geometry design. Four samples of tiled glass mirrors and aluminum foil were prepared and assembled on an offset type low tech parabolic dish to carry on the validation by experimental tests. The ray intercept factor from the simulation and experimental investigation studied by laser beam for the mirror samples varied from 56.06% to 51.4% and 51.21% to 45.61% respectively. Likewise, 57% and 49.47% were the respective results for aluminum foil. The thermal performance was also investigated by the temperature level of the receiver within 30 minutes and the water boiling test procedures. The temperature level varied from 157.170C to 119.200C for glass mirror samples and the result for aluminum foil was 146.380C. The duration obtained from the boiling test resulted in 40 to 69.50 minutes for glass mirror samples and 43.33 minutes for aluminum foil. These results and the reflected image sizes from the experiments indicate that the use of small sized glass mirror or aluminum foil reflector on the dish best fits the curvature of the parabola and attains the higher optical efficiency.
Yacob Gebreyohannes Hiben Petros Gebray Enday Abenezer Bekele Geleta
228507305
Optical Characteristics of Glass Mirror Reflector for off axis Concentrators: A Ray Tracing Approach
Yacob Gebreyohannes Hiben Petros Gebray Enday Abenezer Bekele Geleta Mulu Bayray Kahsay J Lauwaert
107598235
Long term Bioethanol Shift and Transport Fuel Substitution in Ethiopia Status, Prospects, and Implications
In an effort to reduce dependence on imported fossil fuels with a sustainable and environmentally sound improvements, the government of Ethiopia has recognized the need to promote biofuels developm
Yacob Gebreyohannes Hiben
229011028
AFOLAYAN, Adeshina, Olajumoke, YACOB HALISO and Toyin FALOLA (eds) Pentecostalism and Politics in Africa: African Histories and Modernities
AFOLAYAN, Adeshina, Olajumoke, YACOB HALISO and Toyin FALOLA (eds) Pentecostalism and Politics in Africa: African Histories and Modernities. Cham, Switzerland: Palgrave Macmillan, 2018. 452pp. Pbk. ISBN 9783319749112. EUR83.
Andreas Heuser
203074359
DC Arc Self Extinction and Dynamic Arc Model in Open Space Condition Using a Yacob Ladder
Timely extinction of dc fault arc is very important for the stable operation of dc transmission system. However, there are no exact arc extinguishing parameters for reference to design arcing horn. Here, a double supply experimental platform was built, in which a pair of Yacob ladder electrodes was used to achieve the whole arc evolution process from generation, then development until self extinction finally. Arc performance was captured by a high speed camera, and four parameters of arc self extinguishing conditions were recorded. Furthermore, a dynamic arc model was established to interpret the characteristics of arc behavior and self extinction. The research results show that dc arc self extinguishing lengths are 24, 20, 17, and 11 cm when the initial current is 200, 150, 100, and 50 A, respectively. Arc length is mainly dependent on initial current, and a smaller electrode angle is helpful for arc climbing higher and farther. The waveforms of voltage and current of arc evolution are both piecewise functions separated by obvious turning points. Self extinguishing voltage, current, and length are all linear functions of initial current while the duration of arc climbing process is a power function. Arc model shows the arc evolution process is actually a variable acceleration process in the early period and a uniform motion process later. This article is a preliminary study that can provide some references for the design of arcing horn used in dc transmission grounding lines.
IEEE Transactions on Plasma Science
Ruiyang Guan Zhidong Jia Songhai Fan Xinghai Zhang Tao Wang Yuanshi Deng
233468089
The Roles of Person Deixis in Halimah Yacob's Speeches
Person deixis is a type of deixis that exemplified the encoding of participants' role in the speech event where the utterance in question is given. In other words, the expression of person deixis is described as referring to the person who the speaker intends to refer. In political speech, person deixis plays a very important role. It is accustomed represent the speaker's identity through his manner the speaker refers to himself, his opponent, and his audience. In this study, the writer examines person deixis used by the Eighth President of Singapore, Halimah Yacob in her speeches. This study aims to find out the type of person deixis and to explain the roles of personal pronoun (I, we, you, they) used by Halimah Yacob in her speeches. This study uses qualitative method, documentation technique in collecting data. The result shows the types of person deixis that are first person, second person, and third person deixis appeared in Halimah's speeches. The most types of person deixis that used by Halimah Yacob is first person deixis. Another, there are some roles of personal pronoun (I, you, we, they) that used by Halimah Yacob. The most personal pronouns in three speeches used by Halimah Yacob is I than following by pronoun we. Halimah becames a president is not only there is no candidate who passed a Certificate of Eligibility but she wants to show her positive qualities through her personal experiences before becoming as a president by using pronoun I. She also wants to show her commitment seriously to solves the problems that existed in Singapore by using pronoun I. However, Halimah used pronoun I to refers herself rather than used pronoun we as represents herself and her administrations. Halimah become the only one to be blame if there is something happen. Eventhough, Halimah used pronoun I which is distancing herself with her admistrations but she still can get responsibility from the audiences. In this case the second place is the use of personal pronoun we which is refer to Halimah and the audiences. Halimah used personal pronoun we is to shares responsibility and creates involvement with the audiences. So, Halimah used mostly first person deixis (I and we) above to manipulate the use of pronouns which is to create good effects on the audience, such as highlighting her achievements, shortening distance from the audience, denying or distancing themselves from the responsibility for specific political action, and encouraging solidarity.
Dinda Puspitasari
203052003
Zera Yacob's Hatata and the vitality of an Indigenous Ethiopian Philosophy
In today's globalized world, indigenous knowledge is seen as a way of mediating the gap between foreign and local forms of knowledge, envisioning a holistic and sustainable form of development and exploring the wisdom of indigenous cultures. To this extent, it develops a severe critique of programs of modernization and westernization, in return emphasizing the value of artistic, literary, environmental and ethical systems of thought extracted from local communities. Some of the contending labels through which the quest for indigenous knowledge finds expression include indigenous culture, art, environmental ethics, governance, conflict resolution and philosophy. This paper explores primarily the possibility of an indigenous Ethiopian philosophy through an analysis of the ideas of a modern Ethiopian philosopher, Zera Yacob. Animated by the religious controversies and disputes over the nature of true faith in modern Ethiopia, Zera Yacob developed a unique indigenous philosophy in his work the Hatata. In this work, he grappled with questions of religious disputes and mutual coexistence, the relation between ethics and rationality, the laws of man, reason and God, and social and political issues amongst others. Through an interrogation of Zera Yacob's Hatata, this paper argues that, (1) Zera Yacob's philosophy, by developing a system of philosophy guided by the light of reason challenges Western conceptions of Africa and Africans as pre logical, barbaric and uncivilized, (2) the Hatata introduced a rational foundation for ethics that could be used to analyze everyday moral dilemmas, and (3) the Hatata emphasized the notion of religious pluralism which could be used to settle religious disputes and controversies at this point in time.
Fasil Merawi
159138890
PANDANGAN MASYARAKAT SINGAPURA TERHADAPTERPILIHNYA HALIMAH YACOB SEBAGAIPRESIDEN SINGAPURA
Singapura mengadakan pemilihan Presiden untuk periode 2017 2023. Pemilihan yang pada awalnya akan berlangsung pada minggu kedua bulan September 2017, tidak jadi diadakan karena dari tiga kandidat calon Presiden Singapura yang baru hanya Halimah Yacob yang memenuhi syarat sebagai calon Presiden Singapura. Hal ini menyebabkan munculnya calon tunggal dan oleh karena itu sudah dapat dipastikan bahwa Halimah Yacob terpilih sebagai Presiden Singapura yang baru. Tujuan dari penelitian ini adalah untuk mengetahui bagaimana pandangan masyarakt Singapura terhadap terpilihnya Halimah Yacob sebagai Presiden Singapura yang baru. Metode yang digunakan dalam penelitian ini adalah penelitian kuantitatif yang bersifat deskriptif, yaitu suatu teknik yang menjelaskan mengenai analisis data kuantitatif yang ada dengan hasil pengolahan data dalam bentuk angka yang akan menggambarkan situasi yang terjadi di lapangan agar lebih mudah ditangkap oleh siapapun yang membutuhkan. Sedangkan dalam pengumpulan data, penulis menggunakan media questioner serta wawancara dengan subjek penelitian masyarakat Singapura melalui media questioner online Google Docs. Berdasarkan penelitian, dapat diperoleh pandangan masyarakat Singapura terhadap Halimah Yacob yang terpilih sebagai Presiden Singapura yang baru. Kata Kunci: Halimah Yacob, Pandangan, Respon, Pemilihan Presiden Singapura.
Nezatullah Wachid Dewantara