Role of S/Se ratio in chemical bonding of As-S-Se glasses investigated by Raman, x-ray photoelectron, and extended x-ray absorption fine structure spectroscopies

Chalcogenide glasses have attracted considerable attention and found various applications due to their infrared transparency and other optical properties. The As-S-Se chalcogenide glass, with its large glass-formation domain and favorable nonlinear property, is a promising candidate system for tailoring important optical properties through modification of glass composition. In this context, a systematic study on ternary As-S-Se glass, chalcogen-rich versus well-studied stochiometric compositions, has been carried out using three different techniques: Raman spectroscopy, x-ray photoelectron spectroscopy, and extended x-ray absorption fine structure spectroscopy. These complementary techniques lead to a consistent understanding of the role of S/Se ratio in chalcogen-rich As-S-Se glasses, as compared to stochiometric composition, and to provide insight into the structural units (such as the mixed pyramidal units) and evidence for the existence of homopolar bonds (such as Se-Se, S-S, and Se-S), which are the possible structural origin of the high nonlinearity in these glasses

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Systems for Sustainable Energy Supply for Small Villages

ABSTRACT. The main aim of this report is to identify the different sustainable sources and systems of energy and their technological principle which are under substantial development replacing the conventional or traditional sources of energy. It is also the objective of this study to identify the advantages and disadvantages of each system of energy in their actual application now and in the future. In addition, the report discusses the different Energy Systems and Efficient Energy Management systems, which are currently in use. Moreover, the report addresses the environmental, social and economic aspects sustainable energy in the context of buildings and small villages.Máster europeo en Ingeniería de la Construcció

Development of Sustainable Energy Supply Solutions for Fons, Denmark : Analyses and proposal for integrated heat and electricity supply in a 71 household community

ABSTRACT. This research work aims at recommending a suitable renewable energy supply system for the inhabitants of a small village in Denmark called Fons. It envolves studying of the different alternatives of renewable energy supply technologies which has been theoretically developed in the previous group project work entitled "System for Sustainable Energy Sypply for a Small Village" for the production of heat and electricity, being the heat a priority because that is the inhabitant's desire. It is the hope of the research team that implementation of the output of this research work will liberalize the people of Fons community from using unsustainable, non-renewable energy sources such as fossil fuel as their main source of energy.Máster europeo en Ingeniería de la Construcció

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4 m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5 m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 yr, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit