arXiv subjects

Ajay Kumar

Publications and source records attributed to Ajay Kumar.

129 records · Page 8Linked to original sources

arXiv2009

Doppler-tuned Bragg Spectroscopy of Excited Levels in He-Like Uranium: a discussion of the uncertainty contributions

We present the uncertainty discussion of a recent experiment performed at the GSI storage ring ESR for the accurate energy measurement of the He-like uranium 1s2p3P2- 1s2s3S1 intra-shell transition. For this propose we used a Johann-type Bragg spectrometer that enables to obtain a relative energy measurement between the He-like uranium transition, about 4.51 keV, and a calibration x-ray source. As reference, we used the Ka fluorescence lines of zinc and the Li-like uranium 1s22p2P3/2 - 1 s22s 2S1/2 intra-shell transition from fast ions stored in the ESR. A comparison of the two different references, i.e., stationary and moving x-ray source, and a discussion of the experimental uncertainties is presented.

physics.atom-ph↗

arXiv2009

Observation of the 2p3/2 -> 2s1/2 intra-shell transition in He-like uranium

We present the first observation of the 1s2p 3P2 ? 1s2s 3S1 transition in He-like uranium. The experiment was performed at the internal gas-jet target of the ESR storage ring at GSI exploiting a Bragg crystal spectrometer and a germanium solid state detector. Using the 1s2 2p 2P3/2 ? 1s2 2s 2S1/2 transition in Li-like uranium as reference and the deceleration capabilities of the ESR storage rings, we obtained the first evaluation of the He-like heavy ion intra-shell transition energy.

physics.atom-ph↗

arXiv2009

Robot Reliability Using Petri Nets and Fuzzy Lambda-Tau Methodology

Robot reliability has become an increasingly important issue in the last few years due to increased application of robots in many industries (like automobile industry) under hazardous and unstructured environment. As the component failure behavior is dependent on configuration and environment, the available information about the constituent component of robots is most of the time imprecise, incomplete, vague and conflicting and so it is very difficult to analyze their behavior and to predict their failure pattern. The reliability analysis of any system provides an understanding about the likelihood of failures occurring in the system/component and the increased insight about its inherent weakness. The objective of this paper is to quantify the uncertainties that makes the decision more realistic, generic and extendable to application domain. In this paper various reliability parameters (such as mean time between failures, expected number of failures, reliability, availability etc.) are computed using Fuzzy Lambda-Tau methodology. Triangular fuzzy numbers are used to represent failure rates and repair times as they allow expert opinion, linguistic variables, operating conditions, uncertainty and imprecision in reliability information, to be incorporated into system model. Petri Nets are used because unlike the fault tree methodology, the use of Petri Nets allows efficient simultaneous generation of minimal cut and path sets.

math.OC↗