Finite element implementation of Robinson's unified viscoplastic model and its application to some uniaxial and multiaxial problems

A description of the finite element implementation of Robinson's unified viscoplastic model into the General Purpose Finite Element Program (MARC) is presented. To demonstrate its application, the implementation is applied to some uniaxial and multiaxial problems. A comparison of the results for the multiaxial problem of a thick internally pressurized cylinder, obtained using the finite element implementation and an analytical solution, is also presented. The excellent agreement obtained confirms the correct finite element implementation of Robinson's model

On the Spread of Random Interleaver

For a given blocklength we determine the number of interleavers which have spread equal to two. Using this, we find out the probability that a randomly chosen interleaver has spread two. We show that as blocklength increases, this probability increases but very quickly converges to the value $1-e^{-2} \approx 0.8647$. Subsequently, we determine a lower bound on the probability of an interleaver having spread at least $s$. We show that this lower bound converges to the value $e^{-2(s-2)^{2}}$, as the blocklength increases.Comment: 5 pages, published in Proceedings of IEEE International Symposium on Information Theory 2005, Adelaide, Australi

Structural response of SSME turbine blade airfoils

Reusable space propulsion hot gas-path components are required to operate under severe thermal and mechanical loading conditions. These operating conditions produce elevated temperature and thermal transients which results in significant thermally induced inelastic strains, particularly, in the turbopump turbine blades. An inelastic analysis for this component may therefore be necessary. Anisotropic alloys such as MAR M-247 or PWA-1480 are being considered to meet the safety and durability requirements of this component. An anisotropic inelastic structural analysis for an SSME fuel turbopump turbine blade was performed. The thermal loads used resulted from a transient heat transfer analysis of a turbine blade. A comparison of preliminary results from the elastic and inelastic analyses is presented

Cross-Sender Bit-Mixing Coding

Scheduling to avoid packet collisions is a long-standing challenge in networking, and has become even trickier in wireless networks with multiple senders and multiple receivers. In fact, researchers have proved that even {\em perfect} scheduling can only achieve $\mathbf{R} = O(\frac{1}{\ln N})$. Here $N$ is the number of nodes in the network, and $\mathbf{R}$ is the {\em medium utilization rate}. Ideally, one would hope to achieve $\mathbf{R} = \Theta(1)$, while avoiding all the complexities in scheduling. To this end, this paper proposes {\em cross-sender bit-mixing coding} ({\em BMC}), which does not rely on scheduling. Instead, users transmit simultaneously on suitably-chosen slots, and the amount of overlap in different user's slots is controlled via coding. We prove that in all possible network topologies, using BMC enables us to achieve $\mathbf{R}=\Theta(1)$. We also prove that the space and time complexities of BMC encoding/decoding are all low-order polynomials.Comment: Published in the International Conference on Information Processing in Sensor Networks (IPSN), 201

VARIATION IN ANTIOXIDANT POTENTIAL OF CURCUMA LONGA L. COLLECTED FROM DIFFERENT ECOLOGICAL NICHES OF WESTERN HIMALAYAN REGION

Objective: The present study aims to evaluate the nutritional content and antioxidant activities of twenty accessions of turmeric rhizome from various locations of Uttarakhand.Methods: The antioxidant activity was evaluated by different method viz; DPPH radical scavenging activity, ferric reducing antioxidant power assay (FRAP), Hydroxyl radical scavenging activity, Nitric Oxide (NO) scavenging activity, Superoxide anion radical scavenging activity and nutritional value viz; total phenolic content, total flavonoid content, total ortho-dihydroxy phenols, total ascorbic acid content and total antioxidant capacity.Results: Alcoholic extracts of different turmeric rhizomes showed wide variation in abilities to scavenge nitric oxide, hydroxyl, superoxide free radical, DPPH with IC50 values in the range of 39.03-76.14, 39.77-72.85, 43.77-77.13, 64.38-271.95 µg/ml and FRAP value 19.54-54.84 µmole. The total phenolic content, total flavonoid content, total ortho-dihydroxy phenols, total ascorbic acid content and total antioxidant capacity of different alcoholic extracts of rhizomes were found in the range of 11.19-51.49, 6.35-30.95, 0.93-8.12, 0.14-1.29 and 27.44-94.78 mg/g respectively.Conclusion: The alcoholic extract of different accessions of Curcuma longa L. has shown excellent biochemical and antioxidant potential and therefore refers as an important natural source of antioxidant.Â