Adama University

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.

A Look into the Need for Environmental Accounting and Reporting

Abstract: Environmental pollution by organizations has become one of the major treat to individuals’ wellbeing and therefore become highly concerned to global nations. The pollution involves; air, water, land and underground pollution which endangered and threatened species, oceans, atmosphere and land mass. The organizations concerned pay less attention to their treats in their social responsibility and the reporting of such responsibility in their annual reports. Therefore this study seeks to provide the mechanisms in environmental accounting and the need for its reporting by organizations concerned. The mode of the study is conceptual, hence utilizes materials from journal articles, internet and related publications for the topic. The study started with introduction before moving into the main text where; phases of environmental accounting, function and role of environmental accounting, basic dimensions of environmental accounting, structural elements of environmental accounting and role of professional in environmental accounting and reporting were discussed. The study concludes that manufacturing organizations are polluting the environment, and there is need for them to report their activities of compensating the environment as part of their responsibility in their annual reports.

Unsteady mixed convection flow of variable viscosity nanofluid in a micro-channel filled with a porous medium

Abstract: Nanofluids flow and heat transfer in micro-channels have a wide range of attributes in industrial process as well as engineering and biomedical applications. Therefore, the aim of this study is to analyze the hydrodynamic and thermal behaviors of unsteady mixed convection flow of nanofluid in a micro-channel filed with a saturated porous medium. The highly nonlinear governing partial differential equations corresponding to the momentum, energy and concentration profiles were formulated and solved numerically by utilizing the semi-discretization finite difference method. The effects of each governing thermophysical parameters on the micro-channel hydrodynamic and thermal behaviors are discussed with the usage of graphs. The numerical results indicate that the velocity and temperature profiles show an increasing behavior with pressure gradient parameter, variable viscosity parameter, Eckert number, thermal Grashof number, solutal Grashof number and thermophoresis parameter, whereas the concentration profile increases with increasing values of suction/injection Reynolds number, porous medium shape parameter, Forchheimer number, Prandtl number, Schmidt number and thermophoresis parameter. Moreover, the result reveals that the skin friction coefficient, the Nusselt number and the Sherwood number are higher for large values of pressure gradient parameter, thermal Grashof number, Prandtl number and Schmidt number.

Modulation instability in nonlinear chiral fiber

Abstract: In this paper, the rigorous derivations of generalized coupled chiral nonlinear Schrödinger equations (CCNLSEs) and their modulation instability analysis have been explored theoretically and computationally. With the consideration of Maxwell’s equations and Post’s constitutive relations, a generalized CCNLSE has been derived, which describes the evolution of left-handed circularly polarized (LCP) and right-handed circularly polarized (RCP) components propagating through single-core nonlinear chiral fiber. The analysis of modulation instability in nonlinear chiral fiber has been investigated starting from CCNLSEs. Based on a theoretical model and numerical simulations, the difference on the modulation instability gain spectrum in LCP and RCP components through chiral fiber has been analyzed by considering loss and chirality into account. The obtained simulation results have shown that the loss distorts the sidebands of the modulation instability gain spectrum, while chirality modulates the gain for LCP and RCP components in a different manner. This suggests that adjusting chirality strength may control the loss, and nonlinearity simultaneously provides stable modulated pulse propagation.

Herpetofauna and Mammals

Abstract: Of the 64 known amphibian species of Ethiopia, the Lake Tana Sub-basin is believed to contain 19 species of amphibian belonging to 12 genera and 9 families. All of these species are grouped under Order Anura (tail-less frogs). Most of the species found in the area appear to be those that are tolerant to changed habitats. Fourteen species of lizards, 20 species of snakes and one species of freshwater turtle, a total of 35 reptile species occur in the area. However, the herpetofauna taxonomic status and evolutionary relationships of many of the species has not been confirmed using molecular and biogeographic studies or updated using modern phylogeographic approaches. In addition a total of 27 species of mammals that belongs to 16 families are listed. But there is little information on Order-Rodentia (rodents), Lagomorphs (lagomorphs), Erinaceomorpha (hedgehogs and gymnures), Soricomorpha (shrews, moles, and soledons) and Chiroptera (bats). Depending on the land use/land cover history of the area, the wildlife habitats of the area can be categorized in many ways, and each habitat harbors a number of amphibians, reptiles, and mammals. The wildlife values can be expressed in terms of their economic importance, nutritional value, ecological role and socio-cultural significance. Still Ethiopia is not benefiting as there is little attention for the resource. The existence of proclamations specifically dealing with biodiversity does not guarantee conservation unless they are put into action. The main challenge faced in conservation of herpetofauna and mammals is habitat degradation and fragmentation.

A Simple Method to Differentiate between Free-Carrier Recombination and Trapping Centers in the Bandgap of the p-Type Semiconductor

Abstract: In this research, the ranges of the localized states in which the recombination and the trapping rates of free carriers dominate the entire transition rates of free carriers in the bandgap of the p-type semiconductor are described. Applying the Shockley–Read–Hall model to a p-type material under a low injection level, the expressions for the recombination rates, the trapping rates, and the excess carrier lifetimes (recombination and trapping) were described as functions of the localized state energies. Next, the very important quantities called the excess carriers’ trapping ratios were described as functions of the localized state energies. Variations of the magnitudes of the excess carriers’ trapping ratios with the localized state energies enable us to categorize the localized states in the bandgap as the recombination, the trapping, the acceptor, and the donor levels. Effects of the majority and the minority carriers’ trapping on the excess carrier lifetimes are also evaluated at different localized energy levels. The obtained results reveal that only excess minority trapping affects the excess carrier lifetimes, and excess majority carrier trapping has no effect.