A stochastic model to estimate the expected time to seroconversion – threshold as sum of two components

            The spread of the HIV infection has created an pandemic situation all over the world. It has become necessary to have the combined efforts of medical personnel, social workers and mathematicians and statisticians to study the different aspects of this infection and its spread. One of the interesting aspects of  study is to estimate the likely time at which an infected person becomes seropositive. It is in this connection the antigenic diversity threshold is considered. The antigenic diversity threshold is a particular level of the antigenic diversity of the invading antigen beyond which the human immune system breaks down and a person becomes seropositive. In this paper the expected time to seroconversion is derived under the assumption that the antigenic diversity threshold comprises of two components namely the natural antigenic diversity threshold level of human immune system and the threshold  component due to use of ART. Numerical illustration is also provided

Fine tuning of tensile properties in CrCoNi medium entropy alloy through cold rolling and annealing

In the present study, tensile properties of CrCoNi medium entropy alloy with different microstructures (recovery, partial recrystallization, recrystallization) were investigated by subjecting cold-rolled samples to different annealing conditions. The microstructure of the cold-rolled sample showed the presence of severely deformed grains with several deformation twins. Annealing of the cold-rolled samples at 700 degrees C and above for 60 min led to fully recrystallized microstructure, while annealing at temperatures lower than 700 degrees C led to recovery and partially recrystallized microstructures. The annealed samples showed a typical strength-ductility trade-off with an increasing fraction of recrystallized grains and increasing average grain size in samples with partially recrystallized and fully recrystallized microstructure, respectively. Fine tuning of microstructure led to a remarkable combination of strength (similar to 1 GPa) and uniform elongation (28%) in the sample with partially recrystallized microstructure, which consists of similar to 77% of recrystallized grains with an average recrystallized grain size of similar to 3 mu m.11Nsciescopu

Unusual strain-induced martensite and absence of conventional grain refinement in twinning induced plasticity high-entropy alloy processed by high-pressure torsion

A Fe40Mn40Co10Cr10 twinning induced plasticity high-entropy alloy was processed by high-pressure torsion, and its microstructure and mechanical properties were studied. The results indicate the absence of typical grain refinement, but rather the original grain size was retained with the formation of strain-induced HCP martensitic phase.11Nsciescopu

Adaptive fault tolerant resource allocation scheme for cloud computing environments

Cloud computing is an optimistic technology that leverages the computing resources to offer globally better and more efficient services than the collection of individual use of internet resources. Due to the heterogeneous and high dynamic nature of resources, failure during resource allocation is a key risk in cloud. Such resource failures lead to delay in tasks execution and have adverse impacts in achieving quality of service (QoS). This paper proposes an effective and adaptive fault tolerant scheduling approach in an effort to facilitate error free task scheduling. The proposed method considers the most impactful parameters such as failure rate and current workload of the resources for optimal QoS. The suggested approach is validated using the CloudSim toolkit based on the commonly used metrics including the resource utilization, average execution time, makespan, throughput, and success rate. Empirical results prove that the suggested approach is more efficient than the benchmark techniques in terms of load balancing and fault tolerance

Solvent-free synthesis of azomethines, spectral correlations and antimicrobial activities of some E-benzylidene-4-chlorobenzenamines

Some azomethines including substituted benzylidene-4-chlorobenzenamines (E-imines) have been synthesized by fly-ash: PTS catalyzed microwave assisted condensation of 4-chloroaniline and substituted benzaldehydes under solvent-free conditions. The yield of the imines has been found to be more than 85%. The purity of all imines has been checked using their physical constants and UV, IR and NMR spectral data. These spectral data have been correlated with Hammett substituent constants and F and R parameters using single and multi-linear regression analysis. From the results of statistical analysis, the effect of substituents on the above spectral data has been studied. The antimicrobial activities of all imines have been studied using standard methods