Efficient absolute aspect determination of a balloon borne far infrared telescope using a solid state optical photometer

The observational and operational efficiency of the TIFR 1 meter balloon borne far infrared telescope has been improved by incorporating a multielement solid state optical photometer (SSOP) at the Cassegrain focus of the telescope. The SSOP is based on a 1-D linear photo diode array (PDA). The online and offline processing schemes of the PDA signals which have been developed, lead to improvement in the determination of absolute telescope aspect ($\sim$ 0\farcm8), which is very crucial for carrying out the observations as well as offline analysis. The SSOP and its performance during a recent balloon flight are presented here.Comment: To appear in the February 2000 issue of the PAS

Current iodine status and progress over the last decade towards elimination of iodine deficiency in Rajkot District, Gujarat

Objective: To find out prevalence of goitre in primary school children; to compare prevalence with previous survey; to determine median urinary iodine concentration; to assess level of iodine in salt samples at household and retail shop level; and to study profile of salt sold at retail shops. Design & Settings: 30 cluster survey study in primary schools of Rajkot district. Subjects: Children studying in 1st to 7th standard. Methods: Total 70 students including five boys and five girls from 1st to 7th standard present in class on the day of visit were selected randomly for Goitre examination, so, total 2100 students were examined in schools. Urine sample was collected from one boy & one girl from each standard in each cluster. From community, 28 students including two boys and two girls from each standard in same age group were examined and also salt samples were tested from their households. From each village, one retail shop was visited and salts were purchased and tested for iodine on the spot with spot kit. Results: Goitre prevalence was found 8.8% among primary school children compare to 5.6% in 1999. As the age increases the Goitre prevalence also increases except in age group of 12 years. Median urinary iodine excretion level was found 110 µg/L. Iodine level >15 ppm was found in 81% salts samples tested at household level. Conclusion: Present study showed mild Goitre prevalence in primary school children in Rajkot district of Gujarat but still iodine content of salt found inadequate at household level

Mercury or Mercury Free Restorations in Oral Cavity

Amalgam is basically a concoction of metals that has been used as a potent filling material in dentistry for the last 150 years. Amalgam usually consists of silver, mercury, tin and copper. Dental amalgam is a material used to fill cavities of tooth. Over the years, amalgam has become a topic of concern because it contains mercury. Mercury is a naturally occurring metal in the environment. Mercury exists as a liquid in room temperature but when heated, it becomes a gas. Flexibility of amalgam as a filling material is due Mercury. An alloy powder, a compound that is soft in nature when mixed with mercury makes it enough to mix and condense into the tooth. It hardens quickly and offers strong resistance to the forces of biting and chewing. There are studies reported on the safety of amalgam fillings. In 2005, European Union launched a comprehensive mercury strategy to reduce use of mercury. In 2008, countries like Norway and Denmark restricted the use of dental amalgam containing mercury. In 2009, this research was evaluated by U.S. Food and Drug Administration (FDA) and found no rationale to limit the use of amalgam. There are certain restorative materials that are available commercially that are mercury free in nature like Gold, Porcelain, Gallium alloys, Composite resin restoratives etc. They offer many advantages over amalgams containing mercury like: seals the dentin from future decay, reinforces remaining tooth structure, provides smooth and bonded margins, conservative and it blends naturally

Cohesion, Elastic Constants and Vibrational Mechanics of Fcc Platinum

A model in real space has been developed by extending the generalized form of the exponential potential known as extended generalized exponential potential (EGEP) to account for (a) the correct nature of repulsive and attractive components of forces for all the separations in general and that of small separations in particular, (b) the three-body forces such as volume forces in an indirect way in the framework of EGEP through the parameter n, (c) the dielectric screening functions in an alternative and simpler form through the parameter m. The model is employed to compute the cohesive energy, second-order elastic constants and phenon spectra for fcc platinum. The predictions show promising agreement with experimental findings.Author Affiliation: Divesh Verma A. F. School of Engineering and Technology, Dhauj-121 004, Haryana, India M L Verma* and A Verma Department of Physics, GGDSD College, Palwal-121 102, Haryana, India and R P S Rathore Department of Physics, B.M.A.S. Engineering College, Agra-282 002, Uttar Pradesh, India1.A. F. School of Engineering and Technology, Dhauj-121 004, Haryana, India 2.Department of Physics, GGDSD College, Palwal-121 102, Haryana, India 3.Department of Physics, B.M.A.S. Engineering College, Agra-282 002, Uttar Pradesh, Indi