Two‐Dimensional Molybdenum Trioxide and Dichalcogenides

In the quest to discover the properties of planar semiconductors, two‐dimensional molybdenum trioxide and dichalcogenides have recently attracted a large amount of interest. This family, which includes molybdenum trioxide (MoO₃), disulphide (MoS₂), diselenide (MoSe₂) and ditelluride (MoTe₂), possesses many unique properties that make its compounds appealing for a wide range of applications. These properties can be thickness dependent and may be manipulated via a large number of physical and chemical processes. In this Feature Article, a comprehensive review is delivered of the fundamental properties, synthesis techniques and applications of layered and planar MoO₃, MoS₂, MoSe₂, and MoTe₂ along with their future prospects.     

Effect of Bio-Lubricant and Biodiesel-Contaminated Lubricant on Tribological Behavior of Cylinder Liner–Piston Ring Combination

This article addresses the issue of friction and wear characteristics of diesel engine cylinder liner–piston ring combinations under different lubricating conditions using a pin-on-disc wear tribometer. The discs were made out of actual engine cylinder liner material using a casting process. Pins were made out of top compression ring material. The tests were conducted on a pin-on-disc tribometer for wear and friction characteristics of the cylinder liner and piston ring combination with diesel-contaminated rapeseed oil–based bio-lubricant, diesel-contaminated commercial synthetic lubrication oil (SAE 20W40), biodiesel-contaminated commercial synthetic lubrication oil (SAE 20W40), and used (150 h) commercial synthetic lubrication oil (SAE 20W40). Experimental results demonstrated that the rapeseed oil–based bio-lubricant and biodiesel-contaminated synthetic lubricant exhibited better performance in terms of wear, friction, and frictional force under similar operating conditions. Thus, usage of newly formulated bio-lubricant and biodiesel in the long run may have a positive impact on engine life.     

The influence of Al2O3 particulate reinforcement on cyclic stress response and fracture behavior of 6061 aluminum alloy

The cyclic stress response characteristics and cyclic fracture behavior of aluminum alloy 6061 discontinuously reinforced with particulates of Al₂O₃ are presented and discussed. The 6061/Al₂O₃ composite specimens and the unreinforced 6061 aluminum alloy were cyclically deformed using tension-compression loading under constant total strain amplitude control. Both the composite and the unreinforced alloy exhibited softening to failure from the onset of cyclic deformation. The degree of softening was observed to increase at the elevated test temperature for both the composite and the unreinforced counterpart. The intrisic micromechanisms controlling the stress response characteristics during fully-reversed cyclic straining are highlighted and rationale for the observed behavior is discussed. The cyclic fracture behavior of the composite is discussed in terms of the competing influences of intrinsic microstructural effects, deformation characteristics arising from a combination of mechanical and microstructural contributions, cyclic stress response, and test temperature.     

Category learning and change: Differences in sensitivity to information that enhances or reduces intercategory distinctions.

We examined the amenability of abstractions of categories to new and relevant information. In Experiment 1, Ss formed impressions of 2 sets of numbers by periodically estimating the cumulative means of each set. During the 1st half of the procedure, the 2 means were mathematically stable. During the 2nd half of the procedure, the mean of 1 set was modified and the mean of the other set remained unchanged. We predicted and found that the resultant estimates for the modified category changed more when the mean difference between the 2 categories was enhanced than when it was reduced. Experiment 2 suggested that the accentuation effect results from a 2-stage process of category learning (Stage 1) and category change (Stage 2). Experiment 3 replicated the effect with person categories. The relevance of category accentuation is discussed with respect to the modifiability of social beliefs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development and Validation of a Drug Release Rate Method for a Water Soluble Drug in a Liposome Preparation

An in vitro method was developed to determine the rate of drug release from a liposome preparation. Three batches of liposomes containing orciprenaline sulphate were evaluated for release of drug over a 24 hour period in an end-over-end tumbler device. Intra and inter day precision studies indicate good reproducibility for this test method. This method is easy to use in drug development and quality control laboratories to evaluate drug release from liposome formulations.     

A numerical fracture analysis of indentation into thin hard films on soft substrates

In this paper, finite element simulations of spherical indentation of a thin hard film deposited on a soft substrate are carried out. The primary objective of this work is to understand the mechanics of fracture of the film due to formation of cylindrical or circumferential cracks extending inwards from the film surface. Also, the role of plastic yielding in the substrate on the above mechanics is studied. To this end, the plastic zone development in the substrate and its influence on the load versus indentation depth characteristics and the stress distribution in the film are first examined. Next, the energy release rate J associated with cylindrical cracks is computed. The variation of J with indentation depth and crack length is investigated. The results show that for cracks located near the indenter axis and at small indentation depth, J decreases over a range of crack lengths, which implies stability of crack growth. This regime vanishes as the location of the crack from the axis increases, particularly for a substrate with low yield strength. Finally, a method for combining experimental load versus indentation depth data with simulation results in order to obtain the fracture energy of the film is proposed.     

Determining the Order of Processor Transactions in Statically Scheduled Multiprocessors

This paper addresses embedded multiprocessor implementation of iterative, real-time applications, such as digital signal and image processing, that are specified as dataflow graphs. Scheduling dataflow graphs on multiple processors involves assigning tasks to processors (processor assignment), ordering the execution of tasks within each processor (task ordering), and determining when each task must commence execution. We consider three scheduling strategies: fully-static, self-timed and ordered transactions, all of which perform the assignment and ordering steps at compile time. Run time costs are small for the fully-static strategy; however it is not robust with respect to changes or uncertainty in task execution times. The self-timed approach is tolerant of variations in task execution times, but pays the penalty of high run time costs, because processors need to explicitly synchronize whenever they communicate. The ordered transactions approach lies between the fully-static and self-timed strategies; in this approach the order in which processors communicate is determined at compile time and enforced at run time. The ordered transactions strategy retains some of the flexibility of self-timed schedules and at the same time has lower run time costs than the self-timed approach.In this paper we determine an order of processor transactions that is nearly optimal given information about task execution times at compile time, and for a given processor assignment and task ordering. The criterion for optimality is the average throughput achieved by the schedule. Our main result is that it is possible to choose a transaction order such that the resulting ordered transactions schedule incurs no performance penalty compared to the more flexible self-timed strategy, even when the higher run time costs implied by the self-timed strategy are ignored.     

Correlation of Local Constitutive Properties to Global Mechanical Performance of Advanced High-Strength Steel Spot Welds

Metallurgical and Materials Transactions A - Recent results have shown that the strength of resistance spot-welded joints made from advanced high-strength steels (AHSS) do not increase linearly...     

Simulations and bisimulations for analysis of stability with respect to inputs of hybrid systems

Simulation and bisimulation relations define pre-orders on processes which serve as the basis for approximation based verification techniques, and have been extended towards the design of continuous and hybrid systems with complex logic specifications. We study pre-orders between hybrid systems which preserve stability properties with respect to input. We show that these properties are not bisimulation invariant, and hence propose stronger notions which strengthen simulation and bisimulation relations with uniform continuity constraints. We show that uniform continuity is necessary on the relations corresponding to both the state-space and the input-space, and continuity itself does not suffice. Finally, we demonstrate the satisfiability of our definitions by casting the well-known Lyapunov function based techniques for stability analysis as constructing a simple one-dimensional system which is stable and uniformly continuously simulates the original system.