Archives-December  

Composites are currently receiving much attention due to their tuneable chemical and physical properties. ZnO -Al₂O₃ composites attract particular interest because of their possible applications in dye-sensitized solar cells and sensors. Zinc oxide - Aluminum oxide composites were synthesized by hydrothermal method. The precursors used were Zinc Acetate, Aluminum nitrate and Sodium hydroxide. X-ray diffraction (XRD) pattern indicated that the synthesized Al₂O₃ was of hexagonal structure. Thermogravimetric analysis (TGA) was done to determine the thermal properties of the nanopowder UV-Vis spectroscopy and Dielectric analysis were done to determine the optical and dielectric properties of composite.  The results were further discussed.

The purpose of writing this paper is to identify, measure and prioritize the driving affecting factors on Abyek Company (Iranian cement producer) situation in markets. For conceptual framework, 3 main criteria and 13 sub criteria were considered. First of all, by applying Chi-square test, the factors were surveyed in which all 3 ones were affective on compatibility. Also the results of utilizing Average test show that all 3 criteria were placed in favorable place. And finally by using fuzzy TOPSIS technique, the indices were ranked in which “customer relationship management”, “innovation in product” and “competitors related intelligence” were selected as the most important sub criteria.

All real systems that work with digitally represented data require error detecting codes because all real channels are noisy to some extent. The basic goal is to detect errors in data transmission over unreliable or noisy communication channels. Encoding and decoding techniques play a major role in digital communication as the received bit stream usually contains a number of errors. Cyclic Redundancy Codes (CRCs) provide a first line of defense against data corruption in many networks. The basic goal is to control errors in data transmission over unreliable or noisy communication channels. CRC code provides a simple, yet powerful, method for the detection of burst errors during digital data transmission and storage. In this paper simulation is shown and implementation of CRC-32 is done on TMS320VC5416.

In this paper design special frame vertical axis wind turbine and test in the wind tunnel. This design is presented as vertical locations of the three movable vanes that create scoop shape when closed. Scoop shape of frame increases the drag factor and increase the torque, in the other side of impeller movable vanes are opened under action of wind and the air pass freely to reduce the negative torque. Fabricate two models of impeller with movable vanes and with fixed vanes model and test it in wind tunnel. The maximum power coefficient for three frames movable vanes is 0.32 and higher than the same dimensions of model with fixed vanes about 11%.

Stereolithography is one of the Rapid Prototyping technologies, useful for time-compression of the product development cycle. The part characteristics of SL product are essential for the intended functional applications. The parameters are layer thickness, orientation, Post curing, hatch spacing and over cure. The study is conducted on test samples of SL5530 which were built on SLA 5000 machines and tested under ASTM specified test conditions. This study is to investigate the influence of layer thickness on part quality by using the TOPSIS method. The results show that the optimal layer thickness which influences the part quality is 50 microns.

Medical implants the most unavoidable medical device of nowadays has many potent advantages. One of the important limitations of it in medical usage is colonization of biofilm formers on the inner surface of the implants and produce high risk for the implantable material. This study involves the evaluation of one such high rate biofilm forming bacteria, Staphylococcus epidermidis which prevail in the blood. The research materials silicone used for making catheters and stents was coated with chitosan and crosslinked using poly- D,L lactic acid (PDLLA) to provide anti-bacterial activity. This was achieved through a dip coating procedure. The bioefficacy against S. epidermidis, water absorbing ability, withstanding lysozyme degradation and biocompatibility analysis were done to understand whether the coated catheters can be more advantageous than the usual one used in hospitals normally. All the analysis showed more compatible result for the chitosan-PDLLA coated catheter samples. The bioefficacy effect of the dip coated catheters and its ability to eradicate the biofilm formation on the surface designated the modified silicone catheters as efficient implants.

The effects of alkalinity/acidity, addition of copper and zinc, and seeding material on biogas generation using freshly voided cow dung as feedstock were investigated. Experimental set-up for seven digesters, labeled A to F, were carried out in the laboratory with varying measurements of slurry in the digesters, varying pH values for three digesters, some with seeding materials while others with addition of metals –copper and zinc separately. The study was carried out for an hydraulic retention time of 32 days during which volumes of gas generated from all digesters range from 1022cm3 to 1723cm3 with the highest gas produced from digester with the rice husk and banana peels. The results showed best yields with cow dung seeded with rice husk and banana peels, while addition of metals and an alkaline slurry solution of pH = 7 had an improving effect on biogas production.

Speech is an efficient mode of communication among human beings. The shape of glottal excitation may be speaker and language dependent. The objective of this paper is to investigate the quality of speech with respect to glottal excitation modification in Hindi and Dogri languages. For this, recordings of six speakers (3 males and 3 females) were carried out in Dogri and Hindi languages. Cardinal vowels (/a/, /i/, /u/) were extracted from recordings of each speaker. Investigations were carried out by modifying the glottal excitation component of speech and this modification is obtained by adding noise which is a random signal to the glottal excitation component. The analysis of the results showed that quality and intelligibity of speech changes with the modification of the glottal source component in such a manner that identity of a speaker is fully lost and the clarity is degraded though not fully lost. Further, it is perceived that with the modification clarity in male speakers is more degraded than female speakers.

Principals’ leadership behavior plays an important role in transforming societies through the best performance of their teachers. This study was focused on the investigation of leadership behavior of principals at secondary school level in southern districts of Khyber Pakhtunkhwa. The survey research design was used. The study determines leadership behavior of secondary school principals as perceived by teachers. The study was delimited to Southern Districts of Khyber Pakhtukhwa, Pakistan and to the government boys’ Secondary Schools. The population of this study was comprised all teachers of government boys’ Secondary Schools of Southern Districts of Khyber Pakhtunkhwa, Pakistan. Multistage random sampling technique was used, from the population four districts i.e. Kohat, Karak, Bannu and LakkiMarwat were selected randomly and then from each district ten schools and from each school ten teachers were selected randomly and thus the sample was stood 400 teachers of 40 Secondary Schools. The data was collected through a questionnaire developed by the researcher. The collected data was analyzed using Mean and Standard deviation to provide answer to the research question. It was concluded that the perceived leadership behavior of principals was above average and was good according to the scale.

Metal monitoring in food, like teas, provides basic information on safety aspects of food in regulatory processes in terms of suitability of food for consumption, as well as its nutritional value. The aim of this work was to measure the total content of Cd, Cr, Co, Cu, Fe, Mn, Pb and Zn in ten brands of commercially available black tea, on the Ghanaian market. All of the samples were microwave-assisted acid digested followed by measurement of the elemental contents by flame atomic absorption spectrometry (FAAS). The concentrations of all the elements varied among the different brands of tea analysed. The total contents of Fe were comparatively higher than the other analyzed elements and varied between 302.95–27.30 µg/g. the ranges of the other elements observed, in µg/g, were as follows: Cr (<0.006-0.90), (3.85- 9.95), Mn (5.34-219.25), Pb (<0.001-2.05) and Zn(2.80-5.50). Cadmium and Cobolt were below detection limits. All values recorded were below the maximum permissible limit set by the WHO.