Archives-December 

Ni-Al₂O₃-Cr metal matrix hybrid composite coatings were developed in a conventional Watt electroplating solution, containing suspended nanoparticles of alumina and chromium. The characterization of the composite layer was carried out by scanning electron microscopy (SEM), X-ray diffractometry (XRD) and Energy-dispersive X-ray spectroscopy (EDX) facilities. SEM, XRD and EDX studies showed that a novel hybrid Ni-Al₂O₃-Cr metal matrix composite (MMC) coating formed successfully on a pure copper substrate with about 11.5 % and 4.4 % vol. Al₂O₃ and Cr dispersed nanoparticles respectively. A texture modification and grain refinement were found in composite layers. The incorporation of nanoparticles of Al₂O₃ and Cr changed the preferential nickel growth orientation from (220) to the (200) plane. The SEM studies on the morphology of a Ni- Al₂O₃-Cr composite surface illustrated that the nickel column growth slowed down in the composite film and the composite coating had a more condensed and smoother surface compared to pure nickel coatings. The mean grain sizes of the pure nickel and composite coats were determined as 103 and 19 nm respectively. The SEM micrographs showed that the nano particles were uniformly dispersed in the electrodeposited nano-structured Ni matrix and the alumina particles agglomerated in sizes of above 100 nm. The micro-hardness and wear resistance test results showed a remarkable improvement in the mechanical properties of the electroplated nickel by creating a nano composite structure of Ni-Al₂O₃-Cr.

The present research aimed to investigate the thematic concepts of lullabies as folk songs which have passed orally through generations. The themes are hidden ideologies of lullabies that carry cultural attitudes; in this regard, lullabies’ themes can reveal narrators viewpoints which originate from cultures and surrounding areas. Regarding the mentioned elements, the themes suggested by Homayuni (2000) considered as the appropriate model for data extraction using the comparative and descriptive method. The findings showed the same themes in lullabies of both Persian and British cultures; but, in spite of similarities between themes, they had different ways of expression. This is to say, similarities were found in the themes as the basic ideas and hidden layers of lullabies and differences were in their expressing ways as people attitudes.

Depending on the reaction conditions of palladium with tetramethylethylenediamine, first obtained and studied individual and mixed ligands with different composition and structure. Depending on the process conditions, one or two molecules of the tetramethylethylenediamine bidentate coordinated and form a five-star metalchelate cycle. In another obtained cation - anion complex ligand protonated in type of doubly charged cation and organizes the outer sphere of the complex. In the mixed ligands complex of 4 amino pyridine are having the effect of trans influence occurs forced cis-coordination. The study of the biological activity of the synthesized complexes has yielded positive results.

This study aimed to investigate the effect of corpus-based instruction on Iranian EFL learners’ knowledge of idioms. To this end, 100 students from Islamic Azad University, Tonekabon Branch whose major was English Language Translation, was given an OPT in order to homogenize them. Out of this, 60 students whose score fell one standard deviation below the mean was selected and regarded as intermediate students. Then, the subjects were randomly assigned into an experimental group (n=30) and a control group (n=30). The students in both groups were given a pretest. The experimental and control group used the online British National corpus and a course book, namely Every day idioms for reference and practice, respectively. After the experiment, all the participants were given a post test. The results indicated that there was no significant difference between two groups in relation to dependent variable in pre-test (t58=1.58, p>0.05). The finding showed that the differences in pre-post test scores (2.92) clearly showed the efficacy of concordance in enhancing knowledge of idiom. It was showed that there were significance differences in knowledge of idiom between the groups in post test.

Effect of different heavy metals on Vibrio harveyi, V. fischeri, Photobacterium phosphoreum and P. leiognathi were examined. Checkerboard assay used for the detection of the natural metal tolerance levels of a large number of marine luminous eubacteria. In this purpose, we surveyed 57 strains of luminous bacteria for their natural patterns of heavy metal tolerance. The behaviors of these strains were not homogeneous with respect to all metals tested, even within the strains belonging to the same genus. At least 1 to 4 different MICs were detected for every metal except barium and cobalt. Isolated bacteria were tested for the presence of plasmids using the modified alkaline lysis method was effective for identification of plasmids of different sizes. This study revealed that the frequency of the occurrence of plasmids in heavy metal resistance bacteria and suggested that plasmids are highly ubiquitous and predominant in most heavy metal resistant bacteria.

In this article, wave propagation in non-homogenous transversely isotropic electro-magneto-elastic plate of polygonal cross-section is studied using the Fourier expansion collocation method. The frequency equations are obtained from the polygonal cross-sectional boundary conditions, since the boundary is irregular in shape; it is difficult to satisfy the boundary along the surface of the plate directly. Hence, the Fourier expansion collocation method is applied along the boundary to satisfy the boundary conditions. The roots of the frequency equations are obtained by using the secant method applicable for complex roots. The computed non-dimensional frequencies are plotted in the form of dispersion curves and their characteristics are discussed. This problem may be extended to any kinds of cross-sections using the proper geometrical relations.

Traditionally, educators have perceived television as not particularly beneficial to literacy development. Concerns were fueled by findings suggesting that with the introduction of television people spend less time reading books and reading scores decline. However, as the society is striving to make adjustments to the decline in literacy skills and new ways of learning and teaching are being explored, educators are becoming interested in exploring the educational potential of television and video for teaching basic literacy skills such as reading, writing, and math. The interest in television as an educational medium has increased for several reasons. The research literature suggests that the content of television can have four broad types of effects on children. They include behavior, attitudes, beliefs and values, knowledge, and cognitive skills. Many children's television series are educational, ranging from dedicated learning programs to those that indirectly teach the viewers. Some series are written to have a specific moral behind every episode, often explained at the end by the character that learned the lesson. Some television programs are designed with primarily educational purposes in mind, although they might rely heavily on entertainment to communicate their educational messages. In children's programming, edutainment becomes fun and interesting for the child but can still be educational.

Flyash particles are formed during the combustion of coal at very high temperature (above 1500⁰C); it contains some ions as Iron, Aluminium, Silica in their oxide form. It also contains Glass particle along with Cd, Co, Cr, Ni, Se, Pb, Zn, Fl, Hg, particles. Heavy metals from industries are known to have adverse effect on the environment. Similarly, fly ash coming from power plants also has adverse effect on every organism. It was observed that Spirogyra was not found in fly ash discharged water pond while it was present in all the nearby water bodies. ,disasterous effects of heavy metals present in flyash may be the reason. Thus, our present study is mainly focused to elucidate the effect of fly ash on green filamentous algae Spirogyra. It was already found that Microtubules are very sensitive especially to the presence of Cd ions (P. P?ibyl, V. Cepák and V. Zachleder,2008), depending on the Cd concentration present in fly ash and to the time of exposure the disintegration was seen. Microtubules got disintegrated into short fragments or some even completely disappeared.

The paper sought to establish the effect of involvement culture on performance of selected 5-star Chain affiliated hotels in Kenya. The study employed descriptive research design. The study was undertaken in Nairobi Central Business District (CBD). The target population of this study comprised of employees and managers of four 5-star chain hotels. The researcher employed purposive sampling, stratified sampling and simple random sampling techniques. Questionnaires and interview schedule was used in data collection. Data was analyzed using descriptive statistics; frequencies and percentages while correlation analysis was used to assess the effect of involvement culture on performance. Involvement culture was found to have a positive but weak relationship with performance. The study indicated that, the organization should ensure that the employees have shared belief, values and expectation to ensure realization of performance. The researcher therefore recommends that, for organizations to achieve the desired performance all the employees in the organization should be involved to drive the performance agenda.

Background: Iron oxide nanoparticles as contrast elements causing the cancer cells used in MRI and heat therapy are extensive. However, the effects of nanoparticles on human health has not been fully investigated. Objectives: In this study, iron oxide nanoparticles effects on thyroid hormones (T3 and T4) and TSH in adult male Wistar rats were studied. Materials and methods: Three experimental groups of mice daily for 15 days, with concentrations of iron oxide nanoparticles ?g/kg20, ?g/kg50 and ?g/kg150 was dissolved in one ml of distilled water, by gavage tube. Results: Serum T3 levels in experimental and control groups showed no significant change Serum T4 levels in the experimental group receiving the highest dose showed a significant increase compared to control group. Also Yrmy TSH hormone concentration in the groups receiving the medium and maximum doses significantly lower than the control group shows. Conclusion: Experimental results show that iron oxide nanoparticles at high concentrations inhibits the Ndkryny pituitary axis - the hypothalamus And thyroid gland can cause malfunctions Appear to be iron oxide nanoparticles at high concentrations is toxic effect on thyroid function.