A Unified Architecture for the Design and Evaluation of Wireless Fair Queueing Algorithms

Fair queueing in the wireless domain poses significant challenges due to unique issues in the wireless channel such as location-dependent and bursty channel errors. In this paper, we present a wireless fair service model that captures the scheduling requirements of wireless scheduling algorithms, and present a unified wireless fair queueing architecture in which scheduling algorithms can be designed to achieve wireless fair service. We map seven recently proposed wireless fair scheduling algorithms to the unified architecture, and compare their properties through simulation and analysis. We conclude that some of these algorithms achieve the properties of wireless fair service including short-term and long-term fairness, short-term and long-term throughput bounds, and tight delay bounds for channel access.     

Overview of microneedle system: a third generation transdermal drug delivery approach

Transdermal drug delivery has given cardinal contribution to medical practices. First-generation transdermal delivery of small, lipophilic, low-dose drugs and second-generation delivery systems using chemical enhancers, non-cavitational ultrasound and iontophoresis have also resulted in various clinical products provides added functionality. Third-generation delivery systems using microneedles, thermal ablation, microdermabrasion, electroporation and cavitational ultrasound targeting skin’s barrier layer of stratum corneum. Microneedles acquire pronounced intrigue in recent days. Currently, microneedles are advancing through clinical trials for delivery of macromolecules and vaccines, such as insulin, parathyroid hormone and influenza vaccine. The review explains about the concept of transdermal drug microneedle system comprising of microreservoir, micropumps, flow sensors, types of microneedles. Various researches carried out on these components of microneedle system is elaborately discussed in this review.     

The functional importance of Leu15 of human epidermal growth factor in receptor binding and activation

The biological importance of Leu15 of epidermal growth factor(EGF) is suggested by its conservation through evolution, itscritical location in the domain–domain interface of EGFand its close proximity to Arg41, a residue that is crucialfor receptor binding and activation. Mutagenesis of Leu15 ofhuman EGF (hEGF) was employed to examine the role of this residuein the ligand-receptor interaction. The relative receptor affinitiesof the hEGF variants, as determined by radioreceptor competitionassays, varied depending on the amino acid substitution. TheL15F, L15W and L15V hEGF analogues had receptor affinities 45,26 and 18% respectively of wild type hEGF. The L15A and L15Ranalogues displayed receptor affinities of only 2.4 and 1.6%relative to wild type hEGF. No binding of the L15E analoguewas detected. The relative agonist activities, as measured byreceptor tyrosine kinase stimulation assays, generally followeda similar trend. The L15F, L15W and L15V analogues stimulatedthe receptor kinase to a level (V_max) similar to that for wildtype hEGF. A striking difference was observed between the L15Aand L15R variants; although having similar binding affinities,the L15A mutant activated the receptor to only {small tilde}5%of the wild type V_max in contrast to 53% for the L15R mutant¹H-NMR analysis of the L15R and L15A mutants showed only minorstructural alterations that were not sufficient to account forthe dramatic losses in binding and agonist activities. The resultsindicate that both the size and hydrophobicity of the -branchedaliphatic side chain of Leu15 of hEGF are important in the formationof a catalytically active ligand–receptor complex.     

Design and analysis of an algorithm for fair service in error‐prone wireless channels

In order to support diverse communication‐intensive real‐time and non‐real‐time data flows over a scarce, varying and shared wireless channel with location‐dependent and bursty errors, we define a service model that has the following characteristics: short‐term fairness among flows which perceive a clean channel, long‐term fairness for flows with bounded channel error, worst‐case delay bounds for packets, short‐term throughput bounds for flows with clean channels and long‐term throughput bounds for all flows with bounded channel error, expanded schedulable region, and support for both delay sensitive and error sensitive data flows. We present the wireless fair service algorithm, and show through both analysis and simulation that it achieves the requirements of the service model in typical wireless network environments. The key aspects of the algorithm are the following: (a) an enhanced fair queueing based service scheme that supports decoupling of delay and bandwidth, (b) graceful service compensation for lagging flows and graceful service degradation for leading flows, (c) support for real‐time delay sensitive flows as well as non‐real‐time error sensitive flows, and (d) an implementation within the framework of the simple and robust CSMA/CA wireless medium access protocol. This revised version was published online in July 2006 with corrections to the Cover Date.     

Evaluation of activation energy for dynamic strain aging process in 316L(N)/316(N) SS weld joints

Type 316 L(N) Stainless Steel (SS) is being currently used as a structural material for various components of Prototype Fast Breeder Reactor (PFBR). The possibility of using 316 L(N) electrodes for fabrication of 316 L(N) welding joints is being critically examined. This paper discusses about the evaluation of activation energy for Dynamic Strain Aging (DSA) process in 316L(N)/316(N) SS Weld Joints. The Gas Tungsten Arc Welding (GTAW) process was used for the root pass and Gas Metal Arc Welding (GMAW) process was used for the remaining passes. Tensile tests have been conducted in the wide temperature range from room temperature to 1023 K at a strain rate of 3 × 10⁻³ s⁻¹. Yield stress showed a continuous decrease with increasing temperature, with a plateau being observed between 823 and 923 K. A minima in elongation was also observed in this temperature range. These two properties being manifestations of dynamic strain aging, further tests at different strain rates (3 × 10⁻⁵ s⁻¹ to 3 × 10⁻² s⁻¹) were conducted in this temperature range. Detailed analyses of the results were carried out and the solute responsible for dynamic strain aging was identified to be substitutional chromium. Post test analysis of fracture surfaces and deformation substructures were correlated with the changes in tensile properties at different testing temperatures.     

Influence of Sn Grain Size and Orientation on the Thermomechanical Response and Reliability of Pb-free Solder Joints

The size and crystal orientation of Sn grains in Pb-free, near eutectic Sn-Ag-Cu solder joints were examined. A clear dependence of the thermomechanical fatigue response of these solder joints on Sn grain orientation was observed (Sn has a body centered tetragonal crystal structure). Fabricated joints tend to have three orientations in a cyclic twin relationship, but among the population of solder balls, this orientation triplet appears to be randomly oriented. In thermally cycled joints, solder balls with dominant Sn grains having the particular orientation with the c-axis nearly parallel to the plane of the substrate were observed to fail before neighboring balls with different orientations. This results from the fact that the coefficient of thermal expansion of Sn in the basal plane (along the alpha-axis) is half the value along the c-axis; joints observed to be damaged had the maximum coefficient of thermal expansion mismatch between solder and substrate at the joint interface, as well as a tensile stress modes during the hot part of the thermal cycle. Localized recrystallization was observed in regions of maximum strain caused by differential expansion conditions, and its connection with crack nucleation is discussed.     

WTCP: A Reliable Transport Protocol for Wireless Wide-Area Networks

Wireless wide-area networks (WWANs) are characterized by very low and variable bandwidths, very high and variable delays, significant non-congestion related losses, asymmetric uplink and downlink channels, and occasional blackouts. Additionally, the majority of the latency in a WWAN connection is incurred over the wireless link. Under such operating conditions, most contemporary wireless TCP algorithms do not perform very well. In this paper, we present WTCP, a reliable transport protocol that addresses rate control and reliability over commercial WWAN networks such as CDPD. WTCP is rate-based, uses only end-to-end mechanisms, performs rate control at the receiver, and uses inter-packet delays as the primary metric for rate control. We have implemented and evaluated WTCP over the CDPD network, and also simulated it in the ns-2 simulator. Our results indicate that WTCP can improve on the performance of comparable algorithms such as TCP-NewReno, TCP-Vegas, and Snoop-TCP by between 20% to 200% for typical operating conditions.     

Quasi‐static and dynamic nanoindentation and scratch behavior of multifunctional titania/poly(methyl methacrylate) composite

Nanoindentation (NI) and nanoscratch testing was used to determine the dynamic viscoelastic properties of titania reinforced poly(methyl methacrylate) nanocomposites. It was observed that the dynamic NI have a significant effect on the measured indentation modulus and nano‐hardness of the polymer‐based composite. Agreement was found between quasi‐static and dynamic NI result of the nanocomposites. The sinus‐nanoindentation had a limited effect on the measured viscoelastic properties of the composite. However, tribological properties and scratch hardness confirmed that the titania nanofillers act as the friction coefficient modifier in polymer matrix. POLYM. COMPOS., 35:1372–1376, 2014. © 2013 Society of Plastics Engineers     

The female sex pheromone of sugarcane stalk borer,Chilo auricilius identification of four components and field tests

Four pheromonal components have been detected in ovipositor washings and volatiles from female sugarcane stalk borers,Chilo auricilius Dudgeon (Lepidoptera: Pyralidae), using combined gas chromatography-electroantennography. The components have been identified as (I) (Z)-7-do-decenyl acetate, (II) (Z)-8-tridecenyl acetate, (III) (Z)-9-tetradecenyl acetate, and (IV) (Z)-10-pentadecenyl acetate by comparison of their gas chromatographic behavior with that of synthetic standards. In field tests carried out in northern India during 1982–1984, a combination of II, III, and IV in their naturally occurring ratio (841) was shown to provide a highly attractive synthetic source for trap use. (Z)-7-Dodecenyl acetate was found to reduce catches of maleC. auricilius, both when dispensed with the other three components and when released from dispensers surrounding a trap baited with the other three components.