Effect of homogenisation conditions on recrystallisation in the Al-Mg-Mn alloy AA5454

The purpose of the present work is to understand the microstructure development and, particularly, to control the progress of recrystallisation in hot strip in the Al-Mg-Mn alloy AA 5454, which is typically used for the manufacture of structural automotive components. The chemical composition, together with the thermomechanical processing history of this material, has a strong influence on the microstructure of the product and the resulting properties as it is supplied to the customer. Electrical conductivity measurements, thermal analysis and electron microscopy have been carried out to characterise the evolution of precipitation state at various stages in the processing route. The conditions of the homogenisation heat treatment have been varied, and the effect on subsequent recrystallisation after hot rolling has been evaluated in both the as cast and rough rolled condition by optical microscopy techniques. Results indicate that the conditions of homogenisation heat treatment and roughing rolling are critical for the generation of a suitable recrystallised microstructure in AA 5454 hot strip. A new two stage homogenisation practice has been developed to expedite post-rolling recrystallisation in this alloy

Numerical solution for open channel flow with submerged flexible vegetation

The purpose of this study is to explore the suitability of numerical models in estimation o f velocity and flow resistance (Manning n) in open channels with totally submerged flexible vegetation. A three dimensional (3D) numerical model based on arbitrary Lagrangian-Eulerian (ALE) approach has been employed to simulate the effects of various characteristics of selected flexible vegetations to the velocity distribution and flow resistance. The modeling involved simultaneous solution of Navier Stokes equation f or o pen channel flow, s tress-strain relationship for the vegetation structure and ALE algorithm for the moving vegetation boundaries. The numerical computation has been carried out with a n aid of a commercial finite element software package, COMSOL Multiphysics 3.4. The numerical results were validated using experimental data carried out in the laboratory using real vegetations. The accuracy of numerical model compared t o experimental results w as measured in terms of mean absolute error (MAE). The results show that the numerical model which combined the three applications as mentioned above able to predict the velocity and the flow resistance coefficient in open vegetated channel with reasonable accuracy. The MAE calculated for velocity and Manning n is ±0.02

Understadning Faraid: the Case of University Students

The purpose of the study is threefold (1) to examine the level of faraid awareness among university students, as well as (2)the factors that may influence it, and (3)to investigate whether there is any difference between the various groups of respondents based on gender, education level, age and country of origin. The study uses three main statistical techniques to analyse the data, namely, one sample t-test, MANOVA and multiple regression. The data was gathered by distributing the questionnaire to 150 students of International Islamic University Malaysia. The findings indicate that overall the students have good knowledge about faraid. Nevertheless, the students were found to have a misconception and misunderstanding regarding female share in inheritance in Islam. In addition, the findings show that there is significant education level difference in faraid awareness. Finally, the findings conclude that among the variables initially included in the study, only facilitating conditions is significantly influencing the level of awareness of the university students

ARTEMETHER LOADED ETHYLCELLULOSE NANOSUSPENSIONS: EFFECTS OF FORMULATION VARIABLES, PHYSICAL STABILITY AND DRUG RELEASE PROFILE

Objective: The aim of this study was to explore the individual and joint effects of drug: ethylcellulose ratio, content of tween 80 and chloroform: water volume ratio on particles' size and size distribution of artemether loaded ethyl cellulose nanosuspension formulations, aiming to achieve nanosuspension with desired particles properties, stability and drug release profile.Methods: Mixed levels design was used to generate a series of artemether loaded ethylcellulose nanosuspensions that produced by emulsification-solvent evaporation technique. Formulations were qualified for particle size and size distribution using dynamic light scattering technique. Best ranked formulation was then evaluated for stability and drug release rate and kinetics.Results: Drug: polymer ratio, content of surfactant and organic: water volume ratio were found to exert considerable influences (p<0.05) on particle size of produced nanosuspensions, either individually or as joint variables. Peak intensity property of nanosuspensions was found to be influenced by drug: polymer ratio (p<0.05) whereas the influences of different variables on the polydisperse index property appear inconsequential (p>0.05). Best ranked (optimal) artemether nanosuspension proved stable and capable to improve and maintain the release of loaded drug over 24 h, at least under the setting conditions of this study.Conclusion: Focusing on both the individual and joint influences of formulation variables assist in achieving nanosuspension with desired particles characteristics, stability and drug release profile

Multi-level Multi-objective Quadratic Fractional Programming Problem with Fuzzy Parameters: A FGP Approach

The motivation behind this paper is to present multi-level multi-objective quadratic fractional programming (ML-MOQFP) problem with fuzzy parameters in the constraints. ML-MOQFP problem is an important class of non-linear fractional programming problem. These type of problems arise in many fields such as production planning, financial and corporative planning, health care and hospital planning. Firstly, the concept of the -cut and fuzzy partial order relation are applied to transform the set of fuzzy constraints into a common crisp set. Then, the quadratic fractional objective functions in each level are transformed into non-linear objective functions based on a proposed transformation. Secondly, in the proposed model, separate non-linear membership functions for each objective function of the ML-MOQFP problem are defined. Then, the fuzzy goal programming (FGP) approach is utilized to obtain a compromise solution for the ML-MOQFP problem by minimizing the sum of the negative deviational variables. Finally, an illustrative numerical example is given to demonstrate the applicability and performance of the proposed approach

Geometric Quantization on the Super-Disc

In this article we discuss the geometric quantization on a certain type of infinite dimensional super-disc. Such systems are quite natural when we analyze coupled bosons and fermions. The large-N limit of a system like that corresponds to a certain super-homogeneous space. First, we define an example of a super-homogeneous manifold: a super-disc. We show that it has a natural symplectic form, it can be used to introduce classical dynamics once a Hamiltonian is chosen. Existence of moment maps provide a Poisson realization of the underlying symmetry super-group. These are the natural operators to quantize via methods of geometric quantization, and we show that this can be done.Comment: 17 pages, Latex file. Subject: Mathematical physics, geometric quantizatio

The effect of Cosmos caudatus on plasma corticosterone level following a chronic repetitive forced swimming stress in rats

This study examines the effect of Cosmos caudatus on plasma corticosterone levels following a chronic repetitive forced swimming stress (FSS). Male Sprague-Dawley strains of rats weighing 90–120 g were used. The first group was the control, administered only with saline solution. Second and third groups received quercetin (100mg/kg and 200mg/kg) respectively, while the fourth and fifth groups were treated with C. caudatus’s extract (100mg/kg and 200mg/kg) respectively. The rats were subjected to FSS for 15 minutes daily. The tests revealed a significant reduction in plasma corticosterone level in all treated groups (except the second group) compared to the control. At the end of the experiment, the third, fourth and fifth groups had a reduction in plasma corticosterone level which were 153.950 nmol/l ± 2.98, 145.262 nmol/l ± 2.04, 134.488 nmol/l ± 2.70, respectively. The group treated with 200mg/kg of C. caudatus was most significant in reducing plasma corticosterone (p< 0.005). The present study suggests the ability of C. caudatus to reduce the plasma corticosterone level

INFLUENCE OF DRUG SOLUBILITY AND POLYMERS SUPPLY SOURCE ON THE PHYSICAL PERFORMANCE OF MATRIX TABLETS

Objective: The aim of this study is to explore the possible effects of drug solubility and commercial supply sources of HPMC and PVP on physical properties of matrix tablets. Methods: Two different supply sources (A and B) for Hydroxy Propyl Methyl Cellulose (HPMC) as matrix forming polymer and Polyvinyl Pyrrilidone (PVP) as matrix supportive polymer were used with either Chlorphenaramine maleate (CPM), as a water soluble drug or Atenolol (ATN), as a water insoluble drug, to produce a series of matrix formulations using direct compression according to a 23 full factorial design. Matrices were then qualified for friability, hardness, and drug release attributes. Results: Matrix hardness and friability properties demonstrated to be influenced by PVP supply source as an individual factor alone or in combination with drug solubility factor, moreover, both properties were found to be less affected by drug solubility and HPMC supply source, as individual factors. Compared to other factors, drug solubility was found to have a substantial influence on drug dissolution efficiency (DE) and diffusion exponent of the drug release (n) of different matrices. Conclusion: Variation in commercial PVP supply source and drug solubility could possibly result in matrices with different physical performance