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.

Synthesis of Silica Supported Iron Oxide Nanoparticles for Hexavalent Chromium Removal from Aqueous Solutions

Abstract: Iron oxide nanoparticles (NPs) were synthesized by the chemical precipitation method using 1:2 ferric chloride hexahydrate (FeCl3.6H2O) and ferrous sulphate heptahydrate (FeSO4.7H2O) precursors and ammonium hydroxide (NH4OH) precipitating agent. These NPs were evaluated for their performance as adsorbents for hexavalent chromium ions (Cr (VI)) in aqueous solutions. Silicon dioxide gel (SiO2) was also incorporated during synthesis to improve the adsorption characteristics of the NPs. The NPs (with out and with SiO2 gel (iron oxide NPs-SiO2) were characterized by XRD and FTIR spectroscopy. By XRD, it was evidenced that the iron oxide NPs and iron oxide NPs-SiO2 adsorbents were mixed oxides of magnetite (Fe3O4) and maghemite (γ-Fe2O3) with small crystallite size of 13.5 nm and 12.8 nm respectively. The mixed oxides were formed as a result of the synthesis parameters and drying temperature at 1500C in air. The change of the black color of the just synthesized NPs to orange brown also inferred the transformation of Fe3O4 to γ-Fe2O3. Further evidence of mixed oxides is provided by the FTIR analysis wherein the characteristic bands of γ-Fe2O3 around 582 cm-1 and the distinct high-frequency shoulder in the proximity of 635 cm- 1 to 642 cm-1 are evidenced besides those of Fe3O4.The effect of different parameters such as pH, Cr (VI) ions concentration, adsorbent dose and contact time on the efficiency of adsorption showed that the iron oxide NPs-SiO2 adsorbent showed better performance for the removal of Cr (VI) ions under acidic pH at room temperature compared to the iron oxide NPs adsorbent. The maximum uptake of Cr (VI) ions by the iron oxide NPs-SiO2 adsorbent increased from 80% to 96.5% by decreasing its initial concentration from 60 mg l-1 to 20 mg l-1 at optimum conditions. Analysis of the adsorption isotherms of the iron oxide NPs-SiO2 adsorbent by the Langmuir and Freundlich models showed that the experimental data fitted well to the Langmuir model suggesting monolayer coverage of Cr (VI) ions mainly on the outer surface of the adsorbent.

Theorems of Forming and Summing of Natural Numbers and Their Application

Abstract: This paper presents the way to form other set of natural numbers from a given set of natural numbers and formulae to determine the sum of resulting numbers. The other set of natural numbers can be formed either by arranging a given natural numbers in specific order that is by using the principles of permutation rule or by using the principle of product rule provided that a given set of natural numbers should contain equal number of digits. The major areas of study to carry out this particular research work are probability rule, counting principles like permutation rule and product rule, and geometric series. Paper contains some essential theorems that help to arrive at main findings. The objective of this paper is to contribute additional knowledge to the Mathematical and Statistical science. The research results are two fundamental theorems and their applications in Mathematics, Statistics and other expected field of study. They are used to analyze complex numerical data computation and to create a password for a given numerical data with its importance to protect information flow management within a socio economic organization. The findings are foot step for the other related findings and applications that will be presented in the future. The future expected formulas or equations help to solve some difficult scientific and socio economic problems and also to derive approximation formula.

Enhancing Steady-State Entanglement Generated by a Nondegenerate Three-Level Laser with Thermal Reservoir

Abstract: We analyze a nondegenerate three-level cascade laser with an open cavity and coupled to a two-mode thermal reservoir employing the stochastic differential equations for atomic operators associated with the normal ordering. Applying the large-time approximation scheme, we obtain the solutions for the corresponding equations of evolution of the expectation values of atomic operators. Furthermore, employing the resulting solutions, we studied the photon as well as cavity atomic-state entanglement amplification of the cavity radiation.

Optimize Generation Scheduling with Real-Time Power Management System for Isolated Hybrid Microgrid

Abstract: Isolated microgrid with renewable energy sources had vital role for rural electrification from in India. The major challenge in village electrification is generation scheduling from renewable energy sources with respect to load demand on isolated hybrid microgrid. The optimize or scheduling of electrical utilization will not only affect the demand on distribution generation system but also alter the loading of generation system. The RPMS is used for optimizing the generation schedule with respect to load at utilization end for balancing the load radial distribution system. In this paper, the study is carried out for optimize generation scheduling for isolated microgrid with RPMS with respect to time and priority of load utilization. The power management system is communication hub between generation from different renewable energy sources and utilization for improvement of reliability and stability of isolated hybrid microgrid for rural electrification.