An O(k2 + kh2 + h4) arithmetic average discretization for the solution of 1‐D nonlinear parabolic equations

This article develops a new two‐level three‐point implicit finite difference scheme of order 2 in time and 4 in space based on arithmetic average discretization for the solution of nonlinear parabolic equation ε u_xx = f(x, t, u, u_x, u_t), 0 < x < 1, t > 0 subject to appropriate initial and Dirichlet boundary conditions, where ε > 0 is a small positive constant. We also propose a new explicit difference scheme of order 2 in time and 4 in space for the estimates of (?u/?x). The main objective is the proposed formulas are directly applicable to both singular and nonsingular problems. We do not require any fictitious points outside the solution region and any special technique to handle the singular problems. Stability analysis of a model problem is discussed. Numerical results are provided to validate the usefulness of the proposed formulas. © 2006 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2007     

The effects of magnetic field oscillations on the boundary layer flow past a magnetized plate

The effects of harmonic oscillations of amplitude in the magnitude of the magnetic field on the steady boundary layer flowO( ²) due to a uniform free stream past a semi-infinite magnetized flat plate have been discussed. It is observed that the magnetic field distribution does not affect the surface current distribution.

---

Zusammenfassung Die Effekte einer harmonischen Schwingung der Amplitude im Betrag des Magnetfeldes auf die Grenzschicht entlang einer halb-unendlichen magnetischen Platte in gleichförmiger Strömung wird diskutiert. Man findet, daß die magnetische Feldverteilung die Oberflächenströme nicht beeinflußt.

     

Estimation of Delay of M PPM Signals in Laguerre Communications

In this note the maximum likelihood detector forMpulse-position-modulated (PPM) signals in Laguerre communications is derived. A decision-directed maximum likelihood estimator for the delay ofMPPM signals is discussed.     

Which rational numbers are binding numbers?

The concept of the binding number of a graph was introduced by Woodall in 1973. in this paper we characterize the set F_n of all pairs (a, b) of integers such that there is a graph G with n vertices and binding number a/b that has a realizing set of b vertices.     

Kinetics of base hydrolysis ofO-bonded pentaammineglycinatocobalt(III) and pentaammine-β-alaninatocobalt(III) ions

Transition Metal Chemistry - The kinetics and mechanism of the base hydrolysis ofO-bonded pentaammineglycinatocobalt(III) and pentaammine-β-alaninatocobalt(III) ions have been studied...     

Leptogenesis from spin-gravity coupling following inflation

The energy levels of the left- and the right-handed neutrinos are split in the background of gravitational waves generated during inflation, which, in presence of lepton-number-violating interactions, gives rise to a net lepton asymmetry at equilibrium. Lepton number violation is achieved by the same dimension five operator which gives rise to neutrino masses after electroweak symmetry breaking. A net baryon asymmetry of the same magnitude can be generated from this lepton asymmetry by electroweak sphaleron processes.     

Impact of gate-oxide tunneling on mixed-signal design and simulation of a nano-CMOS VCO

Design optimization for performance enhancement in analog and mixed-signal circuits is an active area of research as technology scaling is moving towards the nanometer scale. This paper presents an approach towards the efficient simulation and characterization of mixed-signal circuits, using a 45 nm CMOS voltage controlled oscillator (VCO) with frequency divider as a case study. The performance characteristics of the analog and digital blocks in the circuit are simulated and the accuracy issues arising due to separate analog and digital simulation engines are considered. The tremendous impact of gate tunneling current on device performance is quantitatively analyzed with the help of an “effective tunneling capacitance”, which allows accurate modeling and simulation of digital blocks with almost analog accuracy. To meet the design specifications of the analog VCO using digital CMOS technology, we follow a design of experiments (DOE) approach. The functional specifications of the VCO optimized in this design are the center frequency and minimization of overall power consumption as well as minimization of power due to gate-oxide tunneling current leakage, a component that was not important in previous generations of CMOS technologies but is dominant at 45 nm and below. Due to the large number of available design parameter (gate-oxide thickness and transistor sizes), the concurrent achievement of all optimization goals is difficult. A DOE approach is shown to be very effective and a viable alternative to standard design exploration in the nanometer regime.     

A phenomenological model for bake hardening in minimal carbon steels

The essence of bake hardening is to exploit the classical strain ageing in a positive way to increase the strength of the formed steel sheets used in outer body panel of a passenger car during the paint-baking operation. A new model that takes into account the strengthening contributions from Cottrell atmosphere and precipitate formation has been developed in the present work. The model predicts the increase in strength as a function of the amount of free solute C (calculated as a function of the annealing temperature), the amount of deformation, ageing temperature and time. The model predictions have been found to agree quite well with the experimental results; the individual contributions of Cottrell atmosphere and precipitation strengthening have been quantified.