A Derivation Of The Scalar Propagator In A Planar Model In Curved Space

Given that the free massive scalar propagator in 2 + 1 dimensional Euclidean space is $D(x-y)=\frac{1}{4\pi \rho} 0.25cm e^{-m \rho}$ with $\rho^2=(x-y)^2$ we present the counterpart of $D(x-y)$ in curved space with a suitably modified version of the Antonsen - Bormann method instead of the familiar Schwinger - de Witt proper time approach, the metric being defined by the rotating solution of Deser et al. of the Einstein field equations associated with a single massless spinning particle located at the origin.Comment: 4pages,Presented at FFP10,Nov.24 - 26,2009,UWA,Perth,To appear in AIP Conference Proceeding

A Study Of Orbital Fractures In A Tertiary Health Care Center

A retrospective study of patients with orbital fractures had 48% patients in the age group of 20 – 40 years with male : female ratio of 10:1. Road traffic accidents (71.43%) were the most common cause followed by injury due to fall (20%). Eighty five percent of patients had normal visual acuity at presentation and 65.57% patients had no ocular complaints. Diplopia was present in 14.2% of patients. Of the orbital fractures infraorbital rim was involved in 43.13%, floor in 19.6%, lateral wall in 13.7%, pure blow out in 14.28% and the roof in 2.9%. Important ocular findings were extraocular movements restriction in 9 (10.3%), infraorbital dysaesthesia in 3 (3.4%), enophthalmos in 2, RAPD and globe rupture in 1 patient each. 32 patients underwent surgical management. At the end of 4 months of follow up, 3 had restriction of EOM, 1 patient had vision loss due to globe rupture, 2 had RAPD (optic nerve compression), 1 had lagophthalmos, 1 had exotropia and 1 had atrophic bulbi

Summary of GaAs Solar Cell Performance and Radiation Damage Workshop

The workshop considered the GaAs solar cell capability and promise in several steps: (1) maximum efficiency; (2) space application; (3) major technology problems (AR coating optimization, contacts); (4) radiation resistance; (5) cost and availability; and (6) alternatives. The workshop believes that GaAs solar cells are fast approaching the fulfillment of their potential as candidates for space cells. A maximum efficiency of 20 to 31 percent AMO can be reasonably expected from GaAs based cells, and this may go a little higher with concentration. The use of concentration in space needs to be more carefully evaluated

GaAs workshop report

The advantages of GaAs over silicon are discussed. The substrate problem in solar cell fabrication was reviewed. Future trends in solar energy technology were predicted with special emphasis on cost of production

Electron Radiation Damage of (alga) As-gaas Solar Cells

Solar cells (2 cm by 2 cm (AlGa) As-GaAs cells) were fabricated and then subjected to irradiation at normal incidence by electrons. The influence of junction depth and n-type buffer layer doping level on the cell's resistance to radiation damage was investigated. The study shows that (1) a 0.3 micrometer deep junction results in lower damage to the cells than does a 0.5 micrometer junction, and (2) lowering the n buffer layer doping density does not improve the radiation resistance of the cell. Rather, lowering the doping density decreases the solar cell's open circuit voltage. Some preliminary thermal annealing experiments in vacuum were performed on the (AlGa)As-GaAs solar cells damaged by 1-MeV electron irradiation. The results show that cell performance can be expected to partially recover at 200 C with more rapid and complete recovery occurring at higher temperature. For a 0.5hr anneal at 400 C, 90% of the initial power is recovered. The characteristics of the (AlGa)As-GaAs cells both before and after irradiation are described

Impact of intellectual capital on financial performance and market valuation of firms in India

The Objective of this paper is to empirically investigate the impact of intellectual capital(IC) on the financial performance and market valuation of firms in India. Thirty firms from S&P BSE SENSEX index which consists of 30 firms from across various manufacturing and service sectors. The analysis was carried for a period from FY 2008-2009 to 2012-2013. Multiple linear Regression analysis is used to study the impact of IC on financial performance and market value of these select firms. The paper uses the VAICTM methodology to evaluate the data and finds that the financial performance and market value is indeed influenced by the IC of the firms. This result is crucial for firm's management and policy makers to make IC disclosure and reporting mandatory in firms accounting statements as the stakeholder can get the real picture of the true value of the firm

Processing and Evaluation of Cotton-based Composites for Automotive and Other Applications

Fiber reinforced composites (FRCs) have been used for a long time in structural and semi-structural applications. FRCs have the advantage of lightweight and best property performance compared to traditional materials such as metals. In several instances, disposability of such products becomes a major issue. There has been increasing demand for use of recyclable and or biodegradable composites for automotives, especially due to the recent European Union directives. With the growth of automobiles in the global market, and a simultaneous pressure to address the issue of sustainability, there is continual need for the incorporation of natural fiber based materials into automotives. The focus of this research has been to produce biodegradable cotton fiber-based composites that can be safely disposed off after their intended use without polluting the atmosphere, in an environmentally safe manner. This research deals with cotton-based nonwovens using blends of cotton, flax, kenaf and a biodegradable thermoplastic fiber. Biomax®, Polylactic Acid (PLA), Polyvinyl Acetate (PVAc), and Eastar®bio-copolyester (PTAT) are the chosen thermoplastic fibers that could function as the binders, thus eliminating the use of any non-biodegradable synthetic fiber such as Polypropylene (PP) or a chemical binder. The process involves the fabrication of nonwovens from blends of fibers in different proportions made by air laying or carding to form webs, molding these webs into composites, and subsequent characterization of the composites for their properties such as tensile strength, flexural strength, and acoustic properties. Results from these studies addressing the structure and properties of the composites, contribution from individual constituents, with respect to their suitability for automotive applications are discussed. Basic studies on structure and properties of fibers showed the ability of these natural fibers to form a good bond between thermoplastic polymer such as Eastar, Biomax, and Cellulose Acetate. Fiber bonding studies reinforced this observation. Comparison of Sandwich type composites with Fiber mix type composites showed that the bonding between natural fibers and the binder polymer is better when composites are made from mixed fiber webs. Furthermore, intimate blending is the key to make a composite with good properties. Biodegradable composites were developed from air laid webs of natural fibers (cotton, flax, and kenaf) and binder fibers (Biomax, PLA, and PVAc) by thermal bonding in a hot press. It proved that blending of flax and kenaf increases the tensile strength of the cotton composites. Further, Three point bending test showed that PLA based cotton composites have slightly lower flexural strength compared to conventional PP. Adding about 10% kenaf or flax increases flexural strength substantially, indicating that kenaf and flax act like stiffeners. Acoustics properties of the composites measured by Four point Impedance Tube method showed that blending kenaf or flax increases noise absorption quality of cotton-PLA composites. Notched Izod impact tests showed that the impact strength of PLA and PLAbico binders is higher than that of PP. Moreover blending kenaf or flax increases the impact strength of the composites substantially. Impact strength increases as the composite thickness is raised keeping same basis weight. Comparison of binders, Biomax, PLA, and PVAc fibers in a natural fiber composite showed that PVAc provides more tensile strength and elongation to the cotton or flax rich composite, where as PLA performs similarly in kenaf rich composites. Biomax performance is very close to that of PVAc. In other words, PVAc and Biomax form better composites with cotton and flax than PLA. If PVAc stands out for its superior performance in composites containing more cotton or flax, PLA stands out for the similar performance at lower curing temperature that reduces the bad odor in composites and has processing conditions close to conventional PP. The main advantage of Biomax is its lower cost compared to both PLA and PVAc. Process optimization studies showed that there is an optimum bonding temperature and optimum-curing time for composites. Tensile strength increases as the curing pressure or basis weight/ thickness increases. Increase in tensile strength achieved by blending kenaf or flax (even at 10% level) is substantial. However there is marginal drop in elongation. Further on the basis of these studies, it is expected that viable composite parts containing cotton and other natural fibers can be produced with a thermoplastic binder fiber, that are biodegradable and possess the required properties that are comparable to the traditional polypropylene based composites. Such composites are suitable for automotive and many other semi-structural applications

Is it Time to Start Using Mitochondrial DNA Copy Number as an Indicator of Health and Diseases?

The author discusses whether the medical community should seriously investigate the numerical relation of mitochondrial DNA copy number as a health indicator

Medium energy proton radiation damage to (AlGa)As-GaAs solar cells

The performance of (AlGa)As-GaAs solar cells irradiated by medium energy 2, 5, and 10 MeV protons was evaluated. The Si cells without coverglass and a number of GaAs solar cells with 12 mil coverglass were irradiated simultaneously with bare GaAs cells. The cell degradation is directly related to the penetration of depth of protons with GaAs. The influence of periodic and continuous thermal annealing on the GaAs solar cells was investigated

An exact evaluation of the Casimir energy in two planar models

The method of images is used to calculate the Casimir energy in Euclidean space with Dirichlet boundary conditions for two planar models, namely: i. the non-relativistic Landau problem for a charged particle of mass m for which - irrespective of the sign of the charge - the energy is negative, and ii. the model of a real, massive, noninteracting relativistic scalar field theory in 2 + 1 dimensions, for which the Casimir energy density is non-negative and is expressed in terms of the Lerch transcendent xxx and the polylogarithm xxx with 0 < xxx < 1 and n = 2, 3.Comment: 5 pages, 2 figures,IMFP2009 conference,to appear in forthcoming AIP Conf.Proc.1150 Request:There are three mathematical symbols denoted by xxx in the abstract below which are otherwise present in the abstract of the submission.Could you please include them so that the abstract below is complet