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Institution

Adama University

EducationNazrēt, Ethiopia
About: Adama University is a education organization based out in Nazrēt, Ethiopia. It is known for research contribution in the topics: Population & Adsorption. The organization has 840 authors who have published 1010 publications receiving 5547 citations. The organization is also known as: Adama Science and Technology University & ቴክኖሎጂ ዩኒቨርሲቲ, አዳማ ሳይንስና ቴክኖሎጂ ዩኒቨርሲቲ.


Papers
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Journal ArticleDOI
TL;DR: The Cr-doped ZnO photocatalysts were synthesized through the chromium ion accumulations by water hyacinth (Eichhornia crassipes) in the preparation process, the plant tissues were immersed in different sample flasks containing chromium precursors for 1, 2, 4, 6, and 8 days as discussed by the authors .
Abstract: The Cr-doped ZnO photocatalysts were synthesized through the chromium ion accumulations by water hyacinth (Eichhornia crassipes). In the preparation process, the plant tissues were immersed in different sample flasks containing chromium precursors for 1, 2, 4, 6, and 8 days. The plant tissue containing chromium ion was mixed with zinc precursor followed by calcinations. For simplicity, the prepared Cr-doped ZnO samples with the plant immersed for 1, 2, 4, 6, and 8 days were abbreviated as D1, D2, D4, D6, and D8, respectively. Moreover, pure ZnO was also prepared without the water hyacinth plant accumulated with chromium ion for comparison purposes. The powder sample characterizations were performed and evaluated in the degradation of methylene blue (MB). The Cr-doped ZnO sample (D1) degrades 80% of MB dye while the D2, D4, D6, D8, and pure ZnO samples degrade only 74, 76, 79, 73, and 25%, respectively. On the other hand, without the addition of catalysts (blank), there was no significant degradation of MB dye within 90 min irradiation. Therefore, the degradation performance of Cr-doped ZnO in the presence of optimum amount of chromium dopant and water hyacinth is highly improved than that of pure ZnO. The catalytic improvement may be as a result of reducing the photogenerated electron and hole recombination rates due to the presence of dopants. Moreover, the presence of the Eichhornia crassipes plant in the synthesis of Cr-doped ZnO could also prevent further aggregations and particle size growth and enhance the porosity after calcination.

7 citations

DOI
Legesse Lemecha1
01 Jan 2018
TL;DR: In this article, a mathematical model for corruption by considering awareness created by anti-corruption and counciling in jail is proposed, which is proved to be both epidemiologically and mathematically well posed.
Abstract: We propose a mathematical model for corruption by considering awareness created byanti-corruption and counciling in jail. The model is proved to be both epidemiologically andmathematically well posed. We shown that all solutions of the model are positive and boundedwith initial conditions in a certain meaningful set. The existence of unique corruption-freeand endemic equilibrium points are investigated and the basic reproduction number is com-puted. Then we study the local asymptotic stability of these equilibrium points. The analysisshows that the system has a locally asymptotically stable corruption-free equilibrium pointwhen the reproduction number is less than one and locally asymptotically stable endemicequilibrium point for the reproduction number is greater than one. The simulation resultshows the agreement with the analytical results.

7 citations

Journal ArticleDOI
TL;DR: In this paper, a new idea is proposed to minimize the vortex formation by applying dual tapping hole system, which was tested using a rectangular shape water vessel with dual tapping holes, supplemented by a numerical simulations, in order to evaluate feasibility of the dual-tap hole system.
Abstract: During tapping liquid steel from a converter to a ladle, slag may carry over due to a formation of free surface vortex. Such vortex should be suppressed in order to minimize contamination of the steel by slag. In the present study, a new idea is proposed to minimize the vortex formation by applying dual tapping hole system. The idea was tested using a rectangular shape water vessel with dual tapping holes, supplemented by a numerical simulations, in order to evaluate feasibility of the dual tapping hole system. Both the water model experiment and the numerical simulation showed similar tendencies that the dual tapping hole system is promising to prevent the vortex formation. Experimental results showed that the free surface vortex formation is highly sensitive to shape and configuration of the nozzle. From the numerical simulation, flow characteristics were obtained, and vortex canceling between two nozzles is confirmed. Effect of dual tapping hole increased with increasing distance between two holes in the present experimental condition. Finally, a 1/7.8 scale-down water vessel simulating a real converter was employed in order to confirm the validity of the above findings. The result showed almost the same tendencies with the previous findings.

7 citations

Journal ArticleDOI
TL;DR: In this paper, the performance of a thermoelectric (TE) module consisting of n-type (La0.12Sr0.88)0.95TiO3 and p-type Ca3Co4−xO9+δ materials was investigated.
Abstract: Here, we present the performance of a thermoelectric (TE) module consisting of n-type (La0.12Sr0.88)0.95TiO3 and p-type Ca3Co4−xO9+δ materials. The main challenge in this investigation was operating the TE module in different atmospheric conditions, since n-type has optimum TE performance at reducing conditions, while p-type has optimum at oxidizing conditions. The TE module was exposed to two different atmospheres and demonstrated higher stability in N2 atmosphere than in air. The maximum electrical power output decreased after 40 h when the hot side was exposed to N2 at 600°C, while only 1 h at 400°C in ambient air was enough to oxidize (La0.12Sr0.88)0.95TiO3 followed by a reduced electrical power output. The module generated maximum electrical power of 0.9 mW (∼ 4.7 mW/cm2) at 600°C hot side and δT ∼ 570 K in N2, and 0.15 mW (∼ 0.8 mW/cm2) at 400°C hot side and δT ∼ 370 K in air. A stability limit of Ca3Co3.93O9+δ at ∼ 700°C in N2 was determined by in situ high-temperature x-ray diffraction.

7 citations

Journal ArticleDOI
TL;DR: A moderate pyrochlore solid solution range of 0.64 was observed in the Bi3.36Fe2.08+xSb2.56-x (BFS) system prepared by solid-state reaction at 925°C for 2 days as discussed by the authors.
Abstract: A moderate pyrochlore solid solution range of 0.00 ≤ x ≤ 0.64 was observed in the Bi3.36Fe2.08+xSb2.56-xO14.56-x (BFS) system prepared by solid-state reaction at 925 °C for 2 days. The overall charge compensation required a one-to-one cationic replacement and oxygen vacancies, i.e. Sb5+ ↔Fe3+ - O2–. BFS cubic pyrochlores showed their refined lattice parameters varying linearly in the range of 10.4284 (8)-10.4513(8), thus obeying the Vegard's rule. The measured crystallite sizes by both Scherrer and Williamson-Hall methods were found to be in the range of 46–67 nm; whilst, the larger grain sizes in the range of 0.2–2.9 μm were calculated using scanning electron microscopy (SEM) analysis. The AC impedance analysis also verified a few electrical responses of BFS pyrochlores: (i) BFS pyrochlores had moderate dielectric constants in the range of 24–35 and dielectric losses in the order of 10−1 at room temperature and 1 MHz, (ii) BFS pyrochlores were not electrically homogeneous with bulk capacitances in the order of 10−12 Fcm−1, (iii) a non-Debye type and temperature-dependent relaxation process were discernible and (iv) the movement of charge carrier were either in the long-range or short-range migration subjected to time availability. In addition, BFS pyrochlore thin films had a good capacitive behaviour and electrochemical reversibility, according to the cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) analyses. All these excellent properties rendered BFS pyrochlores to be a suitable material for Class 1 ceramic capacitors.

7 citations


Authors

Showing all 856 results

NameH-indexPapersCitations
Delfim F. M. Torres6070114369
Trilok Singh5437310286
Dattatray J. Late4620511647
Jung Ho Je403286264
Gobena Ameni372074732
Jong Heo372555289
Mahendra A. More362684871
Gyanendra Singh322483198
Dilip S. Joag301273014
Tesfaye Biftu281293225
Salmah Ismail22792151
Rabab Mohammed21921785
Mooha Lee1649821
T. Ganesh1526735
Pandi Anandakumar1518777
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20239
202226
2021332
2020203
2019125
2018101