Fabrication of green and sintered Al: Al2O3 composites using gel-casting and powder metallurgy technique

An effort had been made to fabricate composite of (1-x) wt% Al: x wt % Al2O3 (where x = 0, 10, 20 30, 40, and 50) using both gel casting and powder metallurgy techniques To the best of our knowledge, there was no such literature available on Al-Al2O3 composites prepared through gel-casting technique. Prior to gel-casting zeta-potential, concentration of deflocculating agent, and viscosity were optimized. A mould was designed and fabricated and a new processing route was employed to produce a homogeneous green body which was successful. Microstructure implies that the sintered body was highly porous which could not provide enough mechanical strength. However, the green product was easily machinable. XRD analysis shows no sign of oxidation of aluminium. It has to be further studied before using it for the production. In powder metallurgy, to attain proper mixing aluminium and alumina in their powdered form are milled for 1h in a planetary milling machine with isopropyl alcohol as the wetting agent. Powders were pressed to samples of different shape and were sintered under vacuum. Normally such composites are sintered at nitrogen or argon atmosphere. Some attachments for were designed and manufactured that could be used in the tubular furnace to obtain vacuum. The design was successful and was able to produce a vacuum pressure of 5.6E-6 mbars inside the tube. It had been found that by reinforcing with 20% alumina the hardness of aluminium was increased to 35 HV. Bending test gives the indication that the plasticity is reduced slowly by the addition of alumina into aluminium matrix. It was also found that the tribological properties can be improved by adding 20 weight % of alumina into the metal. Microstructure indicates that the alumina was well dispersed in the aluminium matrix. The composite is easily machinable with HSS tool with minimum tool wear. Therefore it can be used to replace materials in various automotive, aerospace, and automobile industries

The Allocation of European Union Allowances: Lessons, Unifying Themes and General Principles

This paper is the concluding chapter of Rights, Rents and Fairness: Allocation in the European Emissions Trading Scheme, edited by the co-authors and forthcoming from Cambridge University Press. The main objective of this paper is to distill the lessons and general principles to be learnt from the allocation of allowances in the European Union Emission Trading Scheme (EU ETS), i.e. in the world’s first experience with allocating carbon allowances to sub-national entities. We discuss the lessons that emerge from this experience and make some comments on what seem to be more general principles informing the allocation process and on what are the global implications of the EU ETS. As has become obvious during the first allocation phase, the diversity of experience among the Member States is considerable, so that it must be understood that these lessons and unifying themes are drawn from the experience of most of the Member States, not necessarily from all. Lessons and unifying observations are grouped in three categories: those concerning the conditions encountered, the processes employed, and the actual choices.Climate Change, Emission Trading, Allocation, Fairness, EU Policy

2-(1,4-Dioxo-1,4-dihydro-2-naphthyl)-2-methylpropanoic acid

The sterically crowded title compound, C₁₄H₁₂O₄, crystallizes as centrosymmetric hydrogen-bonded dimers involving the carboxyl groups. The naphthoquinone ring system is folded by 11.5 (1)° about a vector joining the 1,4-C atoms, and the quinone O atoms are displaced from the ring plane, presumably because of steric interactions with the bulky substituent

Design, fabrication, and testing of silicon microgimbals for super-compact rigid disk drives

This paper documents results related to design optimization, fabrication process refinement, and micron-level static/dynamic testing of silicon micromachined microgimbals that have applications in super-compact computer disk drives as well as many other engineering applications of microstructures and microactuators requiring significant out-of-plane motions. The objective of the optimization effort is to increase the in-plane to out-of-plane stiffness ratio in order to maximize compliance and servo bandwidth and to increase the displacement to strain ratio to maximize the shock resistance of the microgimbals, while that of the process modification effort is to simplify in order to reduce manufacturing cost. The testing effort is to characterize both the static and dynamic performance using precision instrumentation in order to compare various prototype designs

Rights and Rebuilding in El Salvador: A Case Study in Two Parts

In January 2007, on the 15th anniversary of the signing of the peace accords that ended 12 years of civil war and grave human rights violations in El Salvador, UN Secretary General Ban Ki-moon praised El Salvador as a model for other countries emerging from conflict: “The groundbreaking accords signed in Mexico City in January 1992 not only set El Salvador on a new course. They also provided precedents and experiences that continue to inspire others who are striving to rebuild their societies following conflict. And they continue to be a point of reference for the United Nations, as we assist others on their path to peace.” © Elaine K. Denny & Susan Waltz. All rights reserved. This paper may be freely circulated in electronic or hard copy provided it is not modified in any way, the rights of the author not infringed, and the paper is not quoted or cited without express permission of the author. The editors cannot guarantee a stable URL for any paper posted here, nor will they be responsible for notifying others if the URL is changed or the paper is taken off the site. Electronic copies of this paper may not be posted on any other website without express permission of the author

Teaching Notes: Rights and Rebuilding in El Salvador

We have prepared this two-part case study with two pedagogical purposes in mind: (1) To develop an understanding of the concept (and political meaning) of human rights. (2) To facilitate discussion about processes of reconciliation and reconstruction and the importance of holistic conceptions of rights and security for future stability. © Elaine K. Denny & Susan Waltz. All rights reserved. This paper may be freely circulated in electronic or hard copy provided it is not modified in any way, the rights of the author not infringed, and the paper is not quoted or cited without express permission of the author. The editors cannot guarantee a stable URL for any paper posted here, nor will they be responsible for notifying others if the URL is changed or the paper is taken off the site. Electronic copies of this paper may not be posted on any other website without express permission of the author

Silicon micromachined SCALED technology

Silicon micromachining technology will play an important role in the fabrication of high-bandwidth servo controlled microelectromechanical (mechatronic) components for super-compact disk drives. At the University of California, Los Angeles, and the California Institute of Technology, for the last three years, we have initiated a number of industry-supported joint research projects to develop the necessary technology building blocks for an integrated drive design of the future. These efforts include a silicon read/write head microgimbal with integrated electrical and mechanical interconnects, which targets the next-generation 30% form factor pico-sliders, and an electromagnetic piggyback microactuator in super-high-track-density applications, both of which utilize state-of-the-art silicon micromachining fabrication techniques