Diamond turning of soft semiconductors to obtain nanometric mirror surfaces

Diamond cutting is a viable alternative to grinding and polishing in the fabrication of high-quality soft semiconductors. Investigation of indentation provides useful information for understanding the practical diamond cutting process of brittle materials. Cutting forces and temperatures were analysed using a Kistler dynamometer and an infrared technique. A zero rake angle cutting tool was found to be most efficient, partly because the effective rake is really a strong negative rake brought about by the peculiar configuration of very low feeds and depths of cut. This is explained by means of the comparison of the force distribution between conventional turning and ultraprecision machining. Atomic force microscopy and scanning electron microscopy were used to study the surfaces. Zinc sulfide gave subnanometric surfaces (0.88 m) and zinc selenide gave Ra values of 2.91 nm

An Impossibility Result for High Dimensional Supervised Learning

We study high-dimensional asymptotic performance limits of binary supervised classification problems where the class conditional densities are Gaussian with unknown means and covariances and the number of signal dimensions scales faster than the number of labeled training samples. We show that the Bayes error, namely the minimum attainable error probability with complete distributional knowledge and equally likely classes, can be arbitrarily close to zero and yet the limiting minimax error probability of every supervised learning algorithm is no better than a random coin toss. In contrast to related studies where the classification difficulty (Bayes error) is made to vanish, we hold it constant when taking high-dimensional limits. In contrast to VC-dimension based minimax lower bounds that consider the worst case error probability over all distributions that have a fixed Bayes error, our worst case is over the family of Gaussian distributions with constant Bayes error. We also show that a nontrivial asymptotic minimax error probability can only be attained for parametric subsets of zero measure (in a suitable measure space). These results expose the fundamental importance of prior knowledge and suggest that unless we impose strong structural constraints, such as sparsity, on the parametric space, supervised learning may be ineffective in high dimensional small sample settings.Comment: This paper was submitted to the IEEE Information Theory Workshop (ITW) 2013 on April 23, 201

Role of NABARD in financing marine fisheries projects

National Bank for Agriculture and Rural Development Is the apex organisation dealing with the policy, planning and operational matters relates to credit for development of agriculture and allied sectors including marine fisheries. NABARD has been playing a significant role in promoting marine fisheries development as a refinancing agency as well as developmental agency through conducting training programmes, supporting innovative type of schemes and funding research projects. NABARD has been extending refinance assistance to schemes for acquiring fishing vessels, mariculture and for building Infrastructural facilities. The experiences of NABARD in Implementing various fisheries schemes (s discussed in this paper. The significant features of the pilot credit project Implemented in Orissa with BOBP assistance are highlighted. With view to increasing the participation of financial institutions in the process of marine fisheries development, suggestions are made to Improve flow of credit to marine fisherie

Study On Effect of Boron Carbide, Aluminium Oxide and Graphite On Dry Sliding Wear Behaviour of Aluminium Based Metal Matrix Composite at Different Temperature

The present research has been conducted to study the impact of boron carbide (B4C), aluminium oxide(Al2O3) and graphite on Aluminium 2219 (Al2219). According to current research, B4C and graphite material be a good substitute for Al2219.Reinforced composites and unreinforced Al2219 prepared by a stir casting process. A scanning electron microscope was used to analyze the reinforcement and distribution in the matrix and worn surface of the specimen. Exceptional wear resistance (30%) exhibited by  B4C and graphite-reinforced hybrid composite at 150 ºC in contrast with the unreinforced Al2219. The B4C and Gr reinforcement particulate existence improves the strengthening kinetics in the matrix phase at 150 °C. The artificial neural network used to get the test significance, normalized factor importance and absolute relative error of less than 1%

Working towards fostering programming acceptance in the everyday lives of older and adult people with low levels of formal education:a qualitative case study

With the ever-increasing development of digital technologies, understanding their acceptance or rejection is important. A great deal of research, led by the Technology Acceptance Model (TAM), shows that technology acceptance is a hot and complex topic. Much of it has been quantitative and operationalized within mandatory—workplace/organizational—contexts, where instrumental aspects of technology use (e.g., efficiency and productivity) play a central role. In this chapter, we report on a qualitative case study—based on 3 in-person learning courses—of factors that can help us foster programming acceptance in the everyday lives of older and adult people with low levels of formal education. We discuss the relative relevance of technology acceptance constructs, showing that perceived ease-of-use is much less relevant than perceived usefulness, because all participants had to find the fit of programming in their lives. We show that two social aspects—the figure of the course instructor and the group—were key to introduce programming and encourage decision-making. We also discuss some methodological issues, such as the difficulties in asking validated items of TAM (e.g. “I have the knowledge necessary to use the system”) to our participants

Probing energy barriers and quantum confined states of buried semiconductor heterostructures with ballistic carrier injection: An experimental study

A three-terminal spectroscopy that probes both subsurface energy barriers and interband optical transitions in a semiconductor heterostructure is demonstrated. A metal-base transistor with a unipolar p-type semiconductor collector embedding InAs/GaAs quantum dots (QDs) is studied. Using minority/majority carrier injection, ballistic electron emission spectroscopy and its related hot-carrier scattering spectroscopy measures barrier heights of a buried AlxGa1-xAs layer in conduction band and valence band respectively, the band gap of Al0.4Ga0.6As is therefore determined as 2.037 +/- 0.009 eV at 9 K. Under forward collector bias, interband electroluminescence is induced by the injection of minority carriers with sub-bandgap kinetic energies. Three emission peaks from InAs QDs, InAs wetting layer, and GaAs are observed in concert with minority carrier injection.Comment: 11 pages, 4 figures, submitted to Physical Review

Enhanced Accessibility for People with Disabilities Living in Urban Areas

[Excerpt] People with disabilities constitute a significant proportion of the poor in developing countries. If internationally agreed targets on reducing poverty are to be reached, it is critical that specific measures be taken to reduce the societal discrimination and isolation that people with disabilities continue to face. Transport is an important enabler of strategies to fight poverty through enhancing access to education, employment, and social services. This project aims to further the understanding of the mobility and access issues experienced by people with disabilities in developing countries, and to identify specific steps that can be taken to start addressing problems. A major objective of the project is to compile a compendium of guidelines that can be used by government authorities, advocacy groups, and donor/loan agencies to improve the access of people with disabilities to transport and other services in urban areas