Nano-Wear Mechanism for Ultra-High Molecular Weight Polyethylene (UHMWPE) Sliding Against a Model Hard Asperity

This paper investigates the mechanism of wear-particle generation when a single asperity is passed over the surface of UHMWPE. A single asperity is modelled using a conical diamond-tip indenter attached to a nano-scratch tester. Scratches are produced by passing the indenter over the surface of the polymer in a single pass and multiple passes on a single track or on orthogonally intersecting tracks. The debris-generation process, as observed in the nano-scratch test, is complex and depends upon the direction of scratches. It is found that the rate of wear-debris generation is much higher when two consecutive scratches orthogonally intersect each other compared to when the scratches are made on the same track. Wall formation was observed between orthogonally intersecting scratches, and it is believed that this is central to the low-cycle wear mechanism in these systems.     

N-ocular volume holographic imaging

Volume holographic imaging utilizes Bragg selectivity to optically slice the object space of the imaging system and measure four- (three spatial and one spectral) dimensional object information. The N-ocular version of this method combines multiple-volume holographic sensors and digital postprocessing to yield high-resolution three-dimensional images for broadband objects located at long working distances. We discuss the physical properties of volume holography pertinent to imaging performance and describe two computational algorithms for image inversion based on filtered backprojection and least-squares optimization.     

Reduction of linear systems by canonical forms

A new companion-type realisation of a rational transfer function is introduced. This form is then used for obtaining a reduced-order model. It is possible, using this approach, to simultaneously match time moments, Markov parameters and to retain desired poles, thus combining the methods of partial realisation (Padé approximation) and aggregation.     

Biodegradable polylactide/montmorillonite nanocomposites

Our continuing research on the preparation, characterization, materials properties, and biodegradability of polylactide (PLA)/organically modified layered silicate (OMLS) nanocomposites has yielded results on PLA/montmorillonite nanocomposites. Montmorillonite (mmt) modified with dimethyldioctadecylammonium cation was used as an OMLS for nanocomposite preparation. The internal structure of nanocomposites on the nanometer scale was established with the use of wide-angle X-ray diffraction patterns and transmission electron micrographic observation. All nanocomposites exhibited significant improvement in crystallization behavior, mechanical properties, flexural properties, heat distortion temperature, and O2 gas permeability when compared with pure PLA.     

Permeation enhancers for transdermal drug delivery

The transdermal route has been recognized as one of the highly potential routes of systemic drug delivery and provides the advantage of avoidance of the first-pass effect, ease of use and withdrawal (in case of side effects), and better patient compliance. However, the major limitation of this route is the difficulty of permeation of drug through the skin. Studies have been carried out to find safe and suitable permeation enhancers to promote the percutaneous absorption of a number of drugs. The present review includes the classification of permeation enhancers and their mechanism of action; thus, it will help in the selection of a suitable enhancer(s) for improving the transdermal permeation of poorly absorbed drugs.     

Stress, coping and psychological illness: A cross-cultural study.

This cross-cultural research study aimed to explore the relationship of stress and coping with psychological illness or symptoms among university students in Canada and India. The predictor variables were stress (hassles and life experience), 8 ways of coping (Folkman & Lazarus, 1988), and selected personal-social variables, namely, locus of control, self-esteem, and social support. The criterion variables were 9 psychological symptoms of the Brief Symptom Inventory (BSI; Derogatis & Spencer, 1982). The results revealed that the Indian students reported more psychological symptoms compared to the Canadian students. Stepwise multiple-regression analyses also revealed considerable differences between the 2 samples with respect to the contribution of predictor variables in accounting for variance in the BSI scales. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cold Simulation of Metalloids Transport in Blast Furnaces

Metalloids normally get transferred at the interface of metal droplets passing through the slag system in the dropping zone and at the slag‐metal interface in the hearth zone in the lower region of a blast furnace. In these high temperature processes, the mass transport being the rate‐controlling factor, the viscosity of the slag system determines the kinetics of the refining reactions accompanied by mass and heat transfer at the metal droplets and slag interface. Slag systems generally possess random network structures comprising internal regions of weak ordering. The presence of these regions may result in non‐Newtonian behaviour of the slag. The rheological characteristics of a fluid relating to its network structure is expressed in terms of the indices consistency (k') and flow behaviour (n'). The extent of metalloids presence in hot metal is subjected to their residence time at the slag‐metal interface. The metal droplet descent through a surrounding fluid system has been studied and a co‐relation between drag Reynolds number and modified Reynolds number has been obtained. This correlation has been used to determine the drag velocity of a metal droplet falling through a slag system and the residence time distribution (RTD) of the metalloids at the slag‐metal interface in the lower region of the blast furnace.     

Simulation and Design of Nanocircuits With Resonant Tunneling Devices

New nanotechnology-based devices are being researched to replace CMOS devices in order to overcome CMOS technology's scaling limitations. However, many such devices exhibit nonmonotonic I-V characteristics and uncertain properties which lead to the negative differential resistance (NDR) problem and the chaotic performance. This paper proposes two new circuit simulation approaches that can effectively simulate nanotechnology devices with uncertain input sources and negative differential resistance problem. A new tool called NanoSim-RTD is developed based on the proposed new simulation techniques. The experimental results show a speedup of 1.48-37.1 times when compared with existing simulators. Further, this paper demonstrates a new way to design delay-insensitive nanocircuits, and the designs can be verified by using NanoSim-RTD.     

Genetic neural-based modeling of AC resistance of heating coil used for high-frequency inverter-fed induction cooker

The present paper deals with modeling of AC resistance of twisted litz wires used for high-frequency inverter-fed induction cooker. Several traditional approaches are available, most of which have concentrated in deriving the analytical relationships between the AC resistances with the parameters of the wire. However, it is very difficult to get the exact relationship, due to several reasons. An attempt is made in this paper to model the AC resistance using a three-layered feed-forward Neural Network. For this purpose, four inputs (wire type, number of strand, number of spiral turn and operating frequency) and one output as AC resistance have been considered. Since the performance of Neural Network alone might not be optimal; it is optimized using a binary-coded Genetic Algorithm. Performances of the proposed approach were compared with the method of AC resistance computation proposed by Ferreira. Genetic-neural system has given a very close accuracy, and the computational complexity was found to be very low. Thus, it is suitable for online implementations.