Optomechanical Design of a Space Telescope Primary Mirror

The primary mirror is the most critical component of a space-borne telescope. The size of the primary mirror is the main driver for the resolution of the telescope. A high resolution telescope requires a larger primary mirror with the high-precision requirement of deformation due to space thermal loads, gravity loads in AIT environment and pressure loads during surface polishing. In addition to this, mass is also an important criterion. Telescope mass is also derived from the mass of the primary mirror. So, a lightweight primary mirror with sufficient stiffness to avoid distortion due to gravity and thermal loads is necessary to get the required optical performance from high-resolution telescopes. It will also keep the mirror within its allowable stress limit with a sufficient Margin of Safety in external acceleration and vibrational launch loads so that it can survive during launch. Flexure support is also a very critical component of the primary mirror assembly. The aim of flexure support is to isolate the mirror surface so that it will not distort because of thermal expansion/contraction, gravity loads and mounting stresses. Stiffness of the flexure is a very critical design variable. It should be enough stiff that there will be no plastic deformation due to launch loads and it must be flexible enough that it can isolate the optical surface from the distortion of the optical bench. Researchers have worked on the design solution for large size lightweight primary mirrors and based on the research they have proposed their optimized design for primary mirror and its support. The objective of this research is to propose the optomechanical design solution the primary mirror of a space telescope. It includes designing of the lightweight structure of the primary mirror based on Finite Element Analysis. Open back pocketing will be used to lightweight the primary mirror. The primary mirror support will be designed to a-thermalize and isolate the primary mirror from the external structure. The performance of the primary mirror will be analyzed for deflection due to gravity & thermal loads and stress due to external acceleration and thermal loads based on Finite Element Analysis. Trade off study will be performed for the selection of mirror material and the pocketing shape. The impact of different design variables for pocketing material will be analyzed. On the basis of these analyses a comprehensive workable design solution will be proposed for the Primary Mirror that meet the requirements for surface error and have enough strength to bear launch loads

Brown Bleakness/Brown Greyness: A Textual Analysis of My Body in Australia

Every visible sign of this body is coloured by the imagination of the gaze of its civilizationa1 others. This body suffers/relishes in its very brown visibility. Black hair, black eyes and very brown skin evoke exotic images of Indian monsoons and at the same time signify the \u27dark\u27 unhistorical and mythical times of the writers of kama sutra. This body is also a site of contestations where different discourses compete with each other for dominance. These discourses make a spectacle, an obscene spectacle that displays maimed possibilities, incomplete events, anxieties of the state apparati, victories of the legalities, thwarted subversions, half-born counter-strategies, dynamic negotiations and unpredictable teleologies of fictional desires or desires for fiction - a counter-reality that is always waiting to foreground itself and replace the authorized reality

Warabandi in Pakistan's canal irrigation systems: Widening gap between theory and practice

Irrigation scheduling / Irrigation systems / Irrigation canals / Privatization / Water rights / Social aspects / Economic aspects / Watercourses / Water supply / Equity / Water distribution / Water users' associations / Pakistan / Punjab

Institutional perspectives of land reclamation operations in Punjab: A case study of the Lower Chenab Canal (East) Circle Area

Land reclamationSoil salinityIrrigated sitesIrrigation canalsIrrigation waterInstitutionsLegal aspectsIrrigation schedulingWater availabilityIrrigated farmingCase studies

Irrigation Management in Pakistan and India: Comparing Notes on Institutions and Policies

irrigation management / productivity / privatization / irrigated farming / equity / water distribution / groundwater management / economic aspects / tube wells / price policy / electricity supplies / pumps / India / Pakistan /

Monopoly power and distribution in fragmented markets : the case of groundwater

Using data from Pakistan's Punjab, the authors examine monopoly power in the market for groundwater - irrigation water extracted using private tubewells - a market characterized by barriers to entry and spatial fragmentation. Simple theory predicts that tubewell owners should price-discriminate in favor of their own share tenants. And this analysis of individual groundwater transactions over an 18-month period confirms such price discrimination. And among those studied, tubewell owners and their tenants use considerably more groundwater on their plots than do other farmers. The authors also provide evidence that monopoly pricing of groundwater leads to compensating - albeit small - reallocations of canal water, which farmers exchange in a separate informal market. Despite the substantial misallocation of groundwater, a welfare analysis show that monopoly pricing has limited effects on equity and efficiency. In the long run, a policy aimed at eliminating monopoly pricing would do little to help the poorest farmers.Water and Industry,Water Resources Law,Water Conservation,Environmental Economics&Policies,Water Supply and Systems,Water and Industry,Water Conservation,Water Supply and Sanitation Governance and Institutions,Drought Management,Water Use

USABILITY AND ACCESSIBILITY OF INTERNET BY THE UNIVERSITY STUDENTS OF PAKISTAN: A QUANTITATIVE STUDY OF KHUSHAL KHAN KHATTAK UNIVERSITY KARAK-PAKISTAN

This study was conducted to determine the approach of university’s students towards internet use. This study was carried out at the Khushal Khan Khattak University Karak, Khyber Pakhtunkhwa, Pakistan. The main aim of the study was to know the internet use pattern of university students, Problems in the way of internet use and students satisfaction from University internet facility. The study was based on a quantitative research technique. Data was collected through questionnaires and Stratified Convenience Sampling technique was used for data collection. The findings of the study revealed that students mostly use the internet for academic purposes, social networking and other good purposes. The Internet has a good impact on the academic performance of the students

Bioassay studies of metal(II) complexes of 2,2'-(ethane-1,2-diyldiimino)diacetic acid

Ni(II), Cu(II) and Zn(II) coordination compounds with modified diammine 2,2'-(ethane-1,2-diyldiimino)diacetic acid (EDDA) were prepared and characterized. Coordination complexes of the EDDA were characterized by physical measurements including elemental analysis, IR, UV-Visible, magnetic susceptibilities and conductance measurements. The complexes were screened against four pathogenic bacteria like Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus and their concentrations for maximum inhibition zones were obtained. KEY WORDS: EDDA, Coordination complexes, Antibacterial studies Bull. Chem. Soc. Ethiop. 2011, 25(2), 239-245