Geometric programming method for optimal reliability allocation for a series system subject to cost constraint

The geometric programming method has been used to solve the problem of optimal reliability allocation for a series system subject to cost constraint. There is only one cost vs reliability curve, viz. that of Tillman et al., which is in a posynomial form and hence is used to formulate the cost constraint. A numerical example is given to illustrate the technique.     

Radiative capture cross-sections of isotopes of Gd,Sm and V between 1 and 3 MeV

Fast-neutron radiative capture cross-sections have been measured relative to the ¹²⁷I(n, γ)¹²⁸I reaction cross-section using the comparative activation technique for ¹⁶⁰Gd, ¹⁵⁴Sm and ⁵¹V (using enriched isotopes and Specpure samples) at five different neutron energies between 1 and 3 MeV. The cross-section for ¹⁶⁰Gd is reported for the first time in the above energy region. Experimental values are compared with the statistical-model calculations.     

New method for maximum power consideration in solar cells with and without resistive losses

A new and easy method for maximum power consideration in solar cells has been developed. The general condition for maximum power dP = (?P/?I) dI + (?P/?V) dV = 0 has been used to obtain the required results. Solar cells both with and without losses have been considered.     

Group character tables in discrete transform theory

It has been shown that a transform satisfying a generalized form of the convolution theorem can be described by the group character table of an appropriate finite Abelian group G. Exact correspondence between the transform properties and the underlying group properties is established and it has been demonstrated that many of the digital signal processing problems may be solved efficiently using the group theoretic approach. Sets of permutations are fully characterized such that a permutational convolution defined with respect to them can be converted into a transform product by some invertible transform.     

Operational behaviour of a complex system having shelf-life of the components under preemptive resume repair discipline

Complex system comprised of two types of components (I and II), has been considered. Type I consists of N components connected in series whereas type II consists of components connected in stand-by redundancy. It has been assumed that stand-by component may also fail in its shelf-life. The operational behaviour of such a system has been investigated under preemptive Resume Repair discipline using supplementary variable technique and Laplace Transforms.     

Maintainability and availability calculations for series,parallel and r-out-of-n configurations

Maintainability and availability calculations are given for the following three configurations, viz. series configuration (1-out-of-n : F), parallel configuration (1-out-of-n : G) and r-out-of-n configuration. Mean-time-to-failure (MTTF), mean-time-to-repair (MTTR), and mean-time-to-availability (MTTA) are also computed using basic equations. It is assumed that exponential law holds good both for failure time and repair time.