Leakage current and surface discharge phenomena : effect on tracking and morphological properties of LLDPE-natural rubber compounds

Polymeric insulators are widely used for high voltage outdoor insulating application due to their substantial advantages compared to the porcelain and glass insulators. Although polymer materials have been proven good, research on development of new polymerbased materials is still on going since the benefits of using polymeric materials are not yet utilised to their full potential. In this work, a new formulated thermoplastic elastomer materials that are composed of linear low-density polyethylene (LLDPE) and natural rubber (NR) filled with different loadings of alumina trihydrate (ATH) fillers is presented. A surface tracking and erosion test is conducted to investigate the characteristics of leakage current on the material surface under the influence of wet contaminated conditions. A computer-based leakage current monitoring system is developed to monitor the leakage current waveform pattern as well as its frequency spectrum. The scanning electron microscope is used to investigate the morphological properties of the materials before and after the tracking test

Revenue-productive income tax structures and tax reforms in emerging market economies - evidence from Bulgaria

Using a household budget survey for 1992, The author shows the poor revenue performance and distributional impact of Bulgaria's personal income tax system. He explores the implications for revenue and income distribution of two alternative tax systems - a flat tax and a progressive but simpler three-brackets tax system. He demonstrates that simpler tax structures with lower tax rates could achieve at least equal revenue and distributional objectives and are superior in terms of efficiency and equity. (The findings are robust when Bulgaria's significant tax evasion is included). But tax changes since 1992 have, if anything, moved Bulgaria even further from a simple income tax system: the number of rates and brackets increased from 7 to 10, and the levels of exemption remain unchanged. (Complex, higher rates complicate administration and enforcement and provide incentives for tax evasions. And in the alternative systems the author explores, the poor are protected with higher exemptions.) Fortunately, the country's personal income tax structure began to move toward less nominal progressivity after Bulgaria's 1997 tax reform program. The tax rate in thetop income bracket was reduced from 52 percent to 40 percent, the number of tax brackets was halved, and the exemption level was increased 20 percent (reducing tax burdens on the poor).Environmental Economics&Policies,Public Sector Economics&Finance,Regional Governance,Tax Policy and Administration,Economic Theory&Research,Governance Indicators,Economic Theory&Research,Public Sector Economics&Finance,Environmental Economics&Policies,Tax Policy and Administration

Nongrey radiation effects on the boundary layer of an absorbing gas over a flat plate

Nongrey radiation effects on boundary layer of absorbing gas over flat plat

Distribution of income and the income tax burden in Bulgaria

Using the 1992 Bulgarian household budget survey, the authors analyze the distribution of income and of the income tax burden by income and expenditure class and by rural-urban sector. They find: 1) Low income inequality (although that is changing rapidly). 2) A progressive income tax system. The poor (the lowest two-income decile) pay only 1.4 percent of their per capita income in income tax; the rich (the top decile) pay nearly 6 percent. In-kind income and expenditures are excluded from taxation. 3) The urban sector pays proportionately more in taxes than the rural sector. For example, urban households pay 5.3 percent of their per capita income in income tax, whereas the rural sector pays 2.4 percent. 3) Income tax contributes significantly to reducing income inequality at both the national and sectoral (rural-urban) level, as the poor pay a smaller share of taxes than their share of national income. These results hold whether income or expenditure is used as an indicator of economic well-being. The authors caution that as in-kind income becomes monetized and the economy becomes more market-oriented, the system will become less progressive and urban-rural differences will diminish. They contend that the bias toward higher urban taxes is justified to some extent by the fact that urban households benefit more from government services than rural households do.Payment Systems&Infrastructure,Environmental Economics&Policies,Public Sector Economics&Finance,Economic Theory&Research,Income,Environmental Economics&Policies,Economic Theory&Research,Income,Inequality,Governance Indicators

Wireless Health Monitoring using Passive WiFi Sensing

This paper presents a two-dimensional phase extraction system using passive WiFi sensing to monitor three basic elderly care activities including breathing rate, essential tremor and falls. Specifically, a WiFi signal is acquired through two channels where the first channel is the reference one, whereas the other signal is acquired by a passive receiver after reflection from the human target. Using signal processing of cross-ambiguity function, various features in the signal are extracted. The entire implementations are performed using software defined radios having directional antennas. We report the accuracy of our system in different conditions and environments and show that breathing rate can be measured with an accuracy of 87% when there are no obstacles. We also show a 98% accuracy in detecting falls and 93% accuracy in classifying tremor. The results indicate that passive WiFi systems show great promise in replacing typical invasive health devices as standard tools for health care.Comment: 6 pages, 8 figures, conference pape

Conserved Charges and Supersymmetry in Principal Chiral Models

We report on investigations of local (and non-local) charges in bosonic and supersymmetric principal chiral models in 1+1 dimensions. In the bosonic PCM there is a classically conserved local charge for each symmetric invariant tensor of the underlying group. These all commute with the non-local Yangian charges. The algebra of the local charges amongst themselves is rather more subtle. We give a universal formula for infinite sets of mutually commuting local charges with spins equal to the exponents of the underlying classical algebra modulo its Coxeter number. Many of these results extend to the supersymmetric PCM, but with local conserved charges associated with antisymmetric invariants in the Lie algebra. We comment briefly on the quantum conservation of local charges in both the bosonic and super PCMs.Comment: 18 pages, LaTeX. Revised and up-dated version based on conference talks by JME and NJ

On Euclidean Norm Approximations

Euclidean norm calculations arise frequently in scientific and engineering applications. Several approximations for this norm with differing complexity and accuracy have been proposed in the literature. Earlier approaches were based on minimizing the maximum error. Recently, Seol and Cheun proposed an approximation based on minimizing the average error. In this paper, we first examine these approximations in detail, show that they fit into a single mathematical formulation, and compare their average and maximum errors. We then show that the maximum errors given by Seol and Cheun are significantly optimistic.Comment: 9 pages, 1 figure, Pattern Recognitio

Conformal mapping of unbounded multiply connected regions onto canonical slit regions

We present a boundary integral equation method for conformal mapping of unbounded multiply connected regions onto five types of canonical slit regions. For each canonical region, three linear boundary integral equations are constructed from a boundary relationship satisfied by an analytic function on an unboundedmultiply connected region. The integral equations are uniquely solvable. The kernels involved in these integral equations are the modified Neumann kernels and the adjoint generalized Neumann kernels