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Ann Petry: Miss Muriel and Other Stories
Article on Miss Muriel and Other Stories by Ann Petry
Mangifera indica leaves powder for the removal of rhodamine B.: isotherm and kinetic studies
Adsorption of Rhodamine B (RB) dye onto a non-conventional plant biosorbent, Mangifera indica (mango tree) leaves powder (MLP), was investigated in batch adsorption experiments. Process parameters which include initial dye concentration, contact time and adsorbent dosage were varied in order to evaluate their influence on the adsorption process. Maximum adsorption efficiency (87.00%) was obtained at 75 min. The experimental data fitted well to pseudo-second-order kinetic model and the intra-particle diffusion model, however, diffusion was not only the rate-controlling step. The isotherm modeling suggested that Freundlich isotherm best described the process, with R2 value of 0.972, which is an indication of presence of multi-layer adsorption. The nf value (1.073) shows the adsorption process is favourable, indicating a physisorption. FT-IR results showed the shifting of peak down field and up field which depicts an interaction between the adsorbent and the dye molecules. The results showed that Mangifera indica leaves powder can be used as a low-cost adsorbent for the removal of RB from aqueous media.Keywords: Adsorption, Isotherms, Kinetics, Mangifera indica, Rhodamine B
Some Physical and Mechanical Properties of Daniellia Ogea Harms Green Timber Species
Throughout the antediluvian and up to date, humans keep understanding the nature of wood which has been used to meet some bunches of human’s demands such as in industry, in framing and in war. This paper presents some physical and mechanical properties of Daniellia ogea (Iya) green timber specie freshly felled from matured trees in forests around Ilorin Local Government, Kwara-State, Nigeria and cut into structural sizes within the Wood workshop of University of Ilorin premises according to BS EN 408: 2003. The moisture content and the density were the physical properties tested while the mechanical properties were the modulus of rupture and the local modulus of elasticity in bending strength, the apparent modulus of elasticity, the compressive strength perpendicular to grain then the compressive strength and tensile strength parallel to grain using the Universal Testing Machine of 300kN capacity of the food laboratory of the department of Agriculture of the University. Then the basic and grade stresses were determined and found to conform to the BS 5268 codes of practice. The results obtained post-tests for the moisture content and the density had respectively average values of 140.45% and 854.67 kg/m3. Keywords: Timber, Apparent modulus of elasticity, Stresses, Bending, Density, Moisture content
Controlled capacitance injection into a three-phase induction motor through a single-phase auxiliary stator winding
Abstact: In this paper a controlled static switched capacitor three-phase auxiliary winding fed by a three-phase PWM with single-phase auxiliary winding, which is only magnetically inverter is proposed with some positive results. This solution coupled to the stator main winding, is explored for improving the is, however, complex and there are some doubts about the starting and operating power factor of a three-phase induction controller presented. Other solution presented in [7, 8] is motor. The scheme improves the power factor of the motor applicable only to a wound rotor machine, as the rotor is without compromising significantly on other performances. Important advantages of the scheme include preventing required to be connected to an external circuit. harmonics in the line current, and eliminating regeneration In this paper a single-phase stator auxiliary winding that is possibility as well as preventing high inrush currents at startin
Performance analysis of a three-phase induction motor with capacitance injection
Abstract: In this paper a static switched capacitor with an auxiliary three-phase stator winding, which is only magnetically coupled to the stator main winding, is explored for improving the starting and operating power factor of a three-phase induction motor. The scheme improves the power factor of the motor without compromising significantly on other performances. Important advantages of the scheme include preventing harmonics in the line current, and eliminating regeneration possibility as well as preventing high inrush currents at starting
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