Microstructure and Mechanical Properties of Aluminum Cast Alloy A356 reinforced with Dual-Size B4C Particles

The paper details the studies carried out on a dual-size particulate composite prepared by stir casting using A 356 aluminum alloy and B4C powders. Three composite compositions, viz., A356 plus 2% B4C (44µm size and 105µm size in 1:1 ratio), 4% B4C (3:1 ratio), and 6% B4C (1:3 ratio) were cast in finger molds, from which test specimens were prepared for hardness and tensile tests as well as for metallography. Vickers hardness tests, tensile tests and microstructure analysis using an optical microscope were conducted. The results obtained indicated that the B4C particles were evenly distributed in the alloy matrix. EDS also revealed the presence of B4C in all the three composites.  In general, the hardness and tensile strengths increased with increase in concentration B4C powders. While the increase in hardness was increases less than 15%, there was significant increase (more than 35 %) in tensile strength. However, the ductility represented by % elongation, which was already very low in A 356 cast alloy (24.2%,), further decreased in composites. Tensile fractography results shows inter crystalline fracture where the breakage in the B4C particle instead of deboning were observed

ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES OF TABERNAEMONTANA HEYNEANA WALL. AN ENDEMIC PLANT OF WESTERN GHATS

Objective: The aim of this study was to investigate the antioxidant and antimicrobial properties of different crude extracts of leaves of T. heyneanaMethods: Crude extracts of methanol, chloroform, dichloromethane and dichloroethane of leaf were evaluated for antimicrobial activity by disc diffusion method and antioxidant activity by DPPH (diphenyl-2-picrylhydrazyl) and reducing power assay. Quantitative analysis of total phenolics was done by Folin-Ciocalteau method and total flavonoids by aluminium chloride method.Results: Methanolic extract of T. heyneana exhibited the presence of all the phytochemicals tested except triterpenoids and saponins. The highest phenolic content of 14.0±0.45 mg GAE/g and flavonoid content of 81.62±0.47 mg QE/g were found in methanol extract. The highest DPPH scavenging activity (IC50 20.3±0.56 µg/ml) and reducing power was exhibited by methanolic extract. The methanolic extract showed maximum antibacterial activity of 12.66±0.57 mm zone of inhibition against Staphylococcus aureus and least of 9.23±0.25 mm against Proteus vulgaris.Conclusion: These findings provide scientific evidence to support the traditional use of Tabernaemontana heyneana Wall. and also indicate that the leaves of this species are a promising potential for the development of antioxidant and antimicrobial agents

The costs of scaling up HIV prevention for high risk groups: lessons learned from the Avahan Programme in India.

OBJECTIVE: The study objective is to measure, analyse costs of scaling up HIV prevention for high-risk groups in India, in order to assist the design of future HIV prevention programmes in South Asia and beyond. DESIGN: Prospective costing study. METHODS: This study is one of the most comprehensive studies of the costs of HIV prevention for high-risk groups to date in both its scope and size. HIV prevention included outreach, sexually transmitted infections (STI) services, condom provision, expertise enhancement, community mobilisation and enabling environment activities. Economic costs were collected from 138 non-government organisations (NGOs) in 64 districts, four state level lead implementing partners (SLPs), and the national programme level (Bill and Melinda Gates Foundation (BMGF)) office over four years using a top down costing approach, presented in US$2011. RESULTS: Mean total unit costs (2004-08) per person reached at least once a year and per monthly contact were US$ 235(56-1864) and US$82(12-969) respectively. 35$ 477 per person reached in 2004 to US$145 per person reached in 2008). At the service level also unit costs decreased slightly over time from US$ 68 to US$ 64 per person reached. CONCLUSIONS: Scaling up HIV prevention for high risk groups requires significant investment in expertise enhancement and programme administration. However, unit costs decreased with programme expansion in spite of an increase in the scope of activities

Decoherence on a two-dimensional quantum walk using four- and two-state particle

We study the decoherence effects originating from state flipping and depolarization for two-dimensional discrete-time quantum walks using four-state and two-state particles. By quantifying the quantum correlations between the particle and position degree of freedom and between the two spatial ($x-y$) degrees of freedom using measurement induced disturbance (MID), we show that the two schemes using a two-state particle are more robust against decoherence than the Grover walk, which uses a four-state particle. We also show that the symmetries which hold for two-state quantum walks breakdown for the Grover walk, adding to the various other advantages of using two-state particles over four-state particles.Comment: 12 pages, 16 figures, In Press, J. Phys. A: Math. Theor. (2013

Wearable Internet of Things Medical Alert Device with Fall Detection and Real Time Posture Monitoring

This paper presents an overview about inexpensive fall sensor design. Impact of falls cannot be determined, if there is an aid which can call for help under this circumstances it would be of great help to the person in distress and we are trying to build this aid

Development of Sorghum (Sorghum bicolor (L.) Moench) Endosperm in Varieties of Varying Hardness

Factors responsible for grain hardness in sorghum are not well understood. Therefore, a study was undertaken to observe differences in the developmental processes of three sorghum varieties which vary in endosperm texture: hard, intermediate, and soft. Grain samples were collected at 5 day intervals beginning at 5 days after half-bloom (DAHB) until physiological maturity (40 DAHB) and prepared for viewing with scanning electron microscopy and transmission electron microscopy. Comparisons were made between vitreous and floury endosperm portions of each variety and among the three varieties. The major difference between vitreous and floury endosperm was the degree to which the protein matrix was present and continuous. The protein matrix which surrounds the starch granules forms at approximately 20 DAHB. The proportion of cells in the endosperm with a continuous protein matrix corresponds to the proportion of vitreous endosperm in the mature kernel. A similar sequence of development was observed in the hard, intermediate, and soft varieties. however, the harder varieties appeared to develop faster than the softer varieties. Differences between hard and soft varieties were visible as early as 15 DAHB. In the early stages of endosperm development, the hard variety had a higher concentration of protein bodies in the outer endosperm than the softer varieties