High-efficiency cell concepts on low-cost silicon sheets

The limitations on sheet growth material in terms of the defect structure and minority carrier lifetime are discussed. The effect of various defects on performance are estimated. Given these limitations designs for a sheet growth cell that will make the best of the material characteristics are proposed. Achievement of optimum synergy between base material quality and device processing variables is proposed. A strong coupling exists between material quality and the variables during crystal growth, and device processing variables. Two objectives are outlined: (1) optimization of the coupling for maximum performance at minimal cost; and (2) decoupling of materials from processing by improvement in base material quality to make it less sensitive to processing variables

On Contra gy-Continuous Functions

In this paper, we investigate further properties of the notion of contra gy-continuous functions which was introduced in [4]. We obtain some separation axioms of contra gy-continuous functions and discuss the relationships between contra gy-continuity and other related functions

Emission Spectra from Internal Shocks in Gamma-Ray-Burst Sources

Unsteady activity of gamma-ray burst sources leads to internal shocks in their emergent relativistic wind. We study the emission spectra from such shocks, assuming that they produce a power-law distribution of relativistic electrons and posses strong magnetic fields. The synchrotron radiation emitted by the accelerated electrons is Compton up-scattered multiple times by the same electrons. A substantial component of the scattered photons acquires high energies and produces e+e- pairs. The pairs transfer back their kinetic energy to the radiation through Compton scattering. The generic spectral signature from pair creation and multiple Compton scattering is highly sensitive to the radius at which the shock dissipation takes place and to the Lorentz factor of the wind. The entire emission spectrum extends over a wide range of photon energies, from the optical regime up to TeV energies. For reasonable values of the wind parameters, the calculated spectrum is found to be in good agreement with the burst spectra observed by BATSE.Comment: 12 pages, latex, 2 figures, submitted to ApJ

Forecasting precipitation over Delhi during the south-west monsoon season

The south-west monsoon (June-September) is the major rainy season over India. Information about the occurrence of precipitation and the expected quantity at a specific place is important in many sectors of human activity. In this study, objective methods are developed to forecast the probability of precipitation (POP) and provide the quantity of precipitation forecast (QPF) over Delhi. As the onset of the monsoon at Delhi is around 30 June, the models are developed for the months of July, August and September (JAS) using surface and upper-air data for the period 1985-90 and tested with data from JAS for 1994 and 1995. A multiple linear regression equation is developed to forecast the POP and multiple discriminant analysis is used to produce the QPF in terms of one of four groups (0.1-1.0; 1.1-10.0; 10.1-30.0; and ≥30.1 mm). The QPF model is used only if precipitation is expected to occur (the POP forecast is turned into a categorical forecast). The categorical forecasts based on the POP exhibit positive skill scores consistently with both the development and independent data sets. The model for QPF also performed satisfactorily

Triple solutions for the one-dimensional p-Laplacian

We give conditions on f involving pairs of lower and upper solutions which lead to the existence of at least three solutions to the two point boundary value problem (|u\u27|p -2 u\u27) = q(t) f(t,u,u\u27) on (0,1), u(0) = u(1) = 0

Oscillation of higher order difference equations via comparison

In this paper we shall present some new oscillation criteria for difference equations of the form x(n) + q(n)f(x[n - ]) = 0 and x(n) = q(t)f(x[n - ]) + p(n)F(x[n + ]) via comparison with some difference equations of lower order whose oscillatory behavior are known

Inguinal Hernia and Airport Scanners: An Emerging Indication for Repair?

The use of advanced imaging technology at international airports is increasing in popularity as a corollary to heightened security concerns across the globe. Operators of airport scanners should be educated about common medical disorders such as inguinal herniae in order to avoid unnecessary harassment of travelers since they will encounter these with increasing frequency