Engineered surfaces Part 1.— A philosophy of manufacture

In recent years considerable progress has been made in the characterisation of surface finish in three dimensions, and in the development of protocols which can be used for international standardisation. Although the subject as it has currently developed has much further to go if the process of surface characterisation is to impact on manufacture, control and specification of the manufacturing process itself. Researchers in this important area are beginning to realise that if the subject is to have great impact on manufacturing industries, surface characterisation must be broadened to include measures of surface integrity of the component and in addition be related to the functional demands imposed on the surface. The functional demands being a requirement of the engineering situation in which the components are employed. If these three factors are considered simultaneously, surface characterisation, surface integrity and component function, then a new and important subject is born, the subject of the Engineered Surface. Part 1 of this paper attempts to draw together the elements which go together to create the subject, ‘The Engineered Surface’. The paper presents a method by which this important subject can be developed to the benefit of manufacturing industries. The paper also discusses the importance of a co-ordinated approach to the subject and the way that information can be documented to eventually provide a useful atlas of controlling parameters which are essential for a range of material processing industries as they strive to meet the ever more stringent and cost effective requirements of the manufacture.     

Tensile properties and microstructure of haynes 25 alloy after aging at elevated temperatures for extended times

The tensile properties of Haynes 25 alloy have been measured after various aging treatments, time, and temperature: as received; and aged at 600 °C for three months; 800 °C for 6 and 12 months; and 1000 °C for 3 and 6 months. Contour plots in temperature-ln (time) space were constructed based on the literature and our own data, detailing changes in yield strength, ultimate tensile strength, and tensile elongation. Scanning electron microscopy and transmission electron microscopy observations of the Haynes 25 alloy microstructure provided an explanation of why the properties changed with aging. Intense lattice distortions after aging at 600 °C, the presence of an α-Co₃W, a L1₂-ordered, fcc phase, a=0.357 nm, after aging at 800 °C, and the nucleation and growth of W₃Co₃C carbides from aging at 800 °C and 1000 °C produced the changes in tensile properties. We did not observe either the Co₂W Laves phase or Co₇W₆ γ phase in any of the material conditions we examined, using TEM of thin foils: as received and aged at 600 °C, 800 °C, and 1000 °C. Other researchers believe these phases cause a loss of ductility in the Haynes 25 alloy with prolonged high-temperature exposure.     

Subcube Fault-Tolerance in Hypercubes

We consider the problem of determining the minimum number of faulty processors, K(n, m), and of faulty links, λ(n, m), in an n-dimensional hypercube computer so that every m-dimensional subcube is faulty. Best known lower bounds for K(n, m) and λ(n, m) are proved, several new recursive inequalities and new upper bounds are established, their asymptotic behavior for fixed m and for fixed n − m is analyzed, and their exact values are determined for small n and m. Most of the methods employed show how to construct sets of faults attaining the bounds. An extensive survey of related work is also included, showing connections to resource allocation, k-independent sets, and exhaustive testing.     

Phytoprotective influence of bacteria on growth and cadmium accumulation in the aquatic plant Lemna minor

Certain plants are known to accumulate heavy metals, and can be used in remediation of polluted soil or water. Plant-associated bacteria, especially those that are metal tolerant, may enhance the total amount of metal accumulated by the plant, but this process is still unclear. In this study, we investigated metal enhancement vs. exclusion by plants, and the phytoprotective role plant-associated bacteria might provide to plants exposed to heavy metal. We isolated cadmium-tolerant bacteria from the roots of the aquatic plant Lemna minor grown in heavy metal-polluted waters, and tested these isolates for tolerance to cadmium. The efficiency of plants to accumulate heavy metal from their surrounding environment was then tested by comparing L. minor plants grown with added metal tolerant bacteria to plants grown axenically to determine, whether bacteria associated with these plants increase metal accumulation in the plant.Unexpectedly, cadmium tolerance was not seen in all bacterial isolates that had been exposed to cadmium. Axenic plants accumulated slightly more cadmium than plants inoculated with bacterial isolates. Certain isolates promoted root growth, but overall, addition of bacterial strains did not enhance plant cadmium uptake, and in some cases, inhibited cadmium accumulation by plants. This suggests that bacteria serve a phytoprotective role in their relationship with Lemna minor, preventing toxic cadmium from entering plants.     

Envisioning and accessing new roles for professional psychology.

To support psychology's continued evolution as a profession, it is important to conceptualize roles that psychologists can play in the future and create pathways for developing and accessing them. This article considers a variety of roles that may become central to professional psychology in the future. Important opportunities appear to exist in the areas of psychological management of health and disease, serious mental illness, and public policy. Psychology faces both internal and external barriers to accessing these roles in larger numbers. Strategies related to public education, policy and advocacy, marketing, and training are recommended for overcoming them. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Embodying Product and Process Flexibility to Cope with Challenging Project Deliveries

Four factors make it challenging to manage semiconductor fabrication facility (“fabs”) projects: technical complexity of the product design, need to compress the project duration, need to reduce upfront costs, and unexpected project changes. The strategies employed by practitioners to cope with these challenges form an intricate puzzle. We empirically develop a framework that provides a structure for helping to solve this puzzle, which comprises two principles: investing upfront in a flexible product design and structuring a flexible process. Empirical findings reveal that project teams make commitments early on by overdesigning but also postpone critical decisions by differentiating the scope of their work. Project teams employ other strategies such as increasing communication, using modular architectures, engaging in four-dimensional computer-based modeling, and fabricating components and subsystems off-site. Our analysis yields understanding on the purposes and performance tradeoffs of these strategies, and on how they embody the two principles. Project managers may find the framework useful when deciding which strategies best suit other equally challenging projects.     

Characterization of Nicalon fibres with varying diameters: Part I Strength and fracture studies

Experimental studies have been conducted to examine the strength and fracture behaviour of monofilament Nicalon SiC fibres with diameters ranging from 8 to 22 m. The effects of varying fibre diameter, flaw location and flaw population on the mechanical response of individual fibres were investigated by recourse to extensive fractographic analysis performed on fibres fractured under tensile loading. Results indicate that variations in fibre diameter influence the apparent fibre fracture toughness (K1c), with higher K1c values observed for decreasing fibre diameters. Observations also suggest that the location of the critical flaw may play a role in the fracture of Nicalon fibres. Tensile strength values are shown to increase as the normalized distance of the critical flaw from the fibre centre increases, while critical flaw population appears to be strongly dependent on location. The ratio of K1c to geometry factor (Y) is observed to remain constant with varying flaw location. In addition to surface flaws, three distinct internal flaw populations are seen to cause fracture in Nicalon fibres. Based on these experimental findings, a statistical characterization of the strength of Nicalon fibres with varying diameters is presented in Part II of this paper. © 1998 Chapman & Hall     

Psychological Processes Underlying Risky Decisions in Drug Abusers.

Decision-making deficits are considered to be a significant contributing factor for drug abuse. Drug abusers performed poorly on a simulated gambling task (A. Bechara, H. Damasio, D. Tranel, & S. Anderson, 1994); however, the psychological processes that contribute to these deficits are unknown. The authors used cognitive decision models with a simulated gambling task (SGT) to examine underlying processes of decision making in 66 drug abusers and 58 control participants. As expected, male drug abusers performed more poorly than male controls, and model results showed that male drug abusers placed greater emphasis on wins. The findings for women were less clear because control women performed at chance level on the SGT. Additional studies of gender differences on the SGT are needed to clarify these findings of discrepant performance in the control women. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Signal processing unit for laser tracer providingsubmicron-accuracy diameter measurement

The advent of the space age and, nanotechnology, together with consumer demand for the timely delivery of good quality products has resulted in greater emphasis being placed on instrumentation, in terms of accuracy, tolerance and speed. The authors look at the design of a stand-alone laser tracer signal processing unit that permits diameter measurements to be made on-line at selectable frequencies of up to 500 measurements per second. The system is of the noncontact type and can measure diameters up to 2·0000 mm with a resolution of 0.5 μm. It is shown that with two of these devices connected together, and by externally introducing a means of measuring the distance between the devices, diameters of up to 220·000 mm can be measured; however, the total system resolution is then limited by the resolution of the system that measures the distance between the devices. Suggestions are made as to how this system could be incorporated into an automatic inspection system for quality control