The effect of erosion on the electrochemical properties of AISI 1020 steel

The mechanisms and characteristics of the mechano-electrochemical effect were investigated for eroded AISI 1020 steel specimens. The effect of erosion on open-circuit potential, corrosion potential, linear polarization resistance, and corrosion rate was determined. The corrosion rate was exponentially related to the decrease in corrosion potential and increase in the strain energy. The corrosion rate was quantitatively calculated using a mechano-electrochemical dynamic equation, which is based on the decrease in corrosion potential and increase in strain energy. The calculated rate agrees well with the experimentally measured corrosion rate.     

Study on high strain rate superplasticity of A 6061Al alloy composite reinforced with 30 Vol.% AlN particulate

An investigation on the superplastic behavior of 30 vol.% AlNp/6061Al composite prepared by powder metallurgy (PM) techniques was carried out. Superplastic tensile tests of the composite were performed at strain rates ranging from 10° to 10⁻³ s⁻¹ and at temperatures from 823 to 893 K. A fine-grained structure prior to superplastic testing was obtained by hot rolling after extrusion. The highest total elongation to failure of 438% was achieved at a temperature of 863 K and at an initial strain rate of 1.67×10⁻¹ s⁻¹ and the highest value of the strain rate sensitivity index (m) was 0.42 for the composite. Differential thermal analysis (DTA) was used to investigate the possibility of any partial melting in the vicinity of optimum superplastic temperatures. The formation of a liquid phase is attributed to the melting of the Al-Si eutectic phase at the surface of the AlN particulates at elevated temperatures, as determined by electron probe microanalysis (EPMA). The influence of the microstructure and the fracture behavior on the superplastic behavior of the composite was studied by transmission electronic microscopy (TEM) and scanning electron microscopy (SEM). A large number of matrix filaments were present at the fracture surfaces of the specimens when superplastic deformation of the composite was performed under the optimum superplastic test conditions. The presence of dislocations and fine recrystallized grains in the test specimens suggested that they play an important role in the high-strain-rate superplasticity for this composite.     

Application of centrifugal fields in fused salt electrowinning with a view to reducing electrolytic energy consumption

A high-temperature, laboratory scale electrochemical cell was designed, constructed, and commissioned to investigate the use of centrifugal fields in fused salt electrolysis production of light metals. Fused salt electrowinning of zinc was initially investigated due to the simpler physical and chemical nature of the Zn_(l)‖ZnCl_2(l):KCl_(l)‖Cl_2(g) system. Current efficiencies of 93 pct were obtained for an electrode spacing of 8 mm using 70-mm-diameter plane disc electrodes rotating at 100 rpm, significantly reducing the resistive contribution to the cell voltage. By reducing the immersion depth of the electrodes from 25 to 10 mm, current efficiencies of 88 pct were obtained for an electrode spacing of only 4 mm for the same operating conditions, further decreasing the resistive contribution to the cell voltage.     

Burn-in policies for products having dormant states

Many systems might have a long time dormant period, during which the systems are not operated. For example, most building services products are installed while a building is constructed, but they are not operated until the building is commissioned. Warranty terms for such products may cover the time starting from their installation times to the end of their warranty periods. Prior to the commissioning of the building, the building services products are protected by warranty although they are not operating. Developing optimal burn-in policies for such products is important when warranty cost is analysed. This paper considers two burn-in policies, which incur different burn-in costs, and have different burn-in effects on the products. A special case about the relationship between the failure rates of the products at the dormant state and at the operating state is presented. Numerical examples compare the mean total warranty costs of these two burn-in policies.     

Cognitive-behavioral treatment of late-life generalized anxiety disorder.

This study addressed the efficacy of cognitive-behavioral therapy (CBT), relative to minimal contact control (MCC), in a sample of 85 older adults (age 60 years and over) with generalized anxiety disorder (GAD). All participants completed measures of primary outcome (worry and anxiety), coexistent symptoms (depressive symptoms and specific fears), and quality of life. Results of both completer and intent-to-treat analyses revealed significant improvement in worry, anxiety, depression, and quality of life following CBT relative to MCC. Forty-five percent of patients in CBT were classified as responders, relative to 8% in MCC. Most gains for patients in CBT were maintained or enhanced over 1-year follow-up. However, posttreatment scores for patients in CBT failed to indicate return to normative functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

From psychophysics to the clinic: missteps and advances

People live in different oral sensory worlds. This variation affects health and quality of life. The need to make valid comparisons across individuals/groups to reveal this variation highlighted invalid use of conventional labeled scales (e.g., visual analogue, category scales). Valid comparisons can be made with magnitude matching and the general Labeled Magnitude Scale (gLMS) employing multiple standards (real and remembered), thus permitting associations between oral sensation, preferences, intake (e.g., fats, vegetables), and health outcomes (e.g., cancer, phantoms, burning mouth syndrome). These measurement insights broadly apply to sensory/hedonic assessment of differences across groups in many different fields. As an illustration, we assess differences across groups experiencing different types of pain.     

Multilayer micromolding of degradable polymer tissue engineering scaffolds

Precise surface geometrical morphologies have been shown to improve cellular proliferation, adhesion, and functionality. It has been found that cells respond strongly to feature dimensions a fraction of their size. In this paper, soft lithography techniques were applied to microfabricate polydimethylsiloxane molds with precisely controlled micro-scale patterns. Three-dimensional polycaprolactone (PCL) scaffolds were fabricated using a multilayer micromolding (MMM) method. Proper heating and stamping parameters were developed for micromolding PCL. This process allowed control of the size, shape, and spacing of support structures within the scaffold. The micromolding of multiple layers with independent features allowed for alignment between layers. The high porosity, abundant interconnections, and sharp features were inherent advantages of the scaffolds. Human osteosarcoma cells were seeded in the 3-D scaffolds for cell growth testing. Fluorescent microscopy and scanning electron micrographs showed that cells responded well to the 3-D scaffolds and the scaffolds regulated cell morphology and adhesion.     

Role of set in visual word recognition: Activation and activation blocking as nonautomatic processes.

The semantic priming effect in lexical decision is widely assumed to reflect automatic processes when the prime is merely read. In contrast, semantic priming is typically eliminated when the prime is subjected to a letter search. The present experiments demonstrate that semantic priming (a) occurs following letter search given a short stimulus onset asynchrony between prime and probe and (b) is reinstated in the standard, simultaneous letter search condition when such trials are mixed with delayed probe trials. These results are discussed in terms of the role of set in the context of an interactive activation framework. Activation and activation blocking are seen as nonautomatic processes controlled by set so as to balance bottom-up and top-down influences. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Preweanling rats solve the Morris water task via directional navigation.

Adult rats show a preference for directional navigation over place navigation in the Morris water task. Here, the authors investigated whether preweanling rats with a newly developed ability to perform the water task also solve the task via directional navigation. After 24-day-old rats were trained to find a hidden platform in a fixed spatial location, a no-platform probe trial was conducted with the pool either in the same position as that used during training (no shift group) or shifted to a new position in the room (shift group). The authors found that rats in the shift group did not search for the platform at its absolute spatial location but rather navigated in the same direction that the platform was located during training and searched at the correct distance from the pool wall, resulting in a search at a location that was never trained. This pattern of results suggests that young rats learn to solve the water task by navigating in a particular direction rather than navigating to a precise place--a finding that may have implications for understanding hippocampal development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neighbourhood density effects in reading aloud: New insights from simulations with the DRC model.

A series of nine simulations with the Dual Route Cascaded (DRC) model (M. Coltheart, K. Rastle, C. Perry, R. Langdon, & J. Ziegler, 2001) investigated neighbourhood density (N) effects in nonword and word naming. Two main findings emerged from this work. First, when naming nonwords there are two loci for the effect of N in the model, contrary to M. Coltheart et al.'s single locus explanation of what the model is doing. The early N effect involves interactive activation between the orthographic lexicon and the letter units such that high N facilitates letter identification, which in turn affects the nonlexical route. The late N effect arises from activation in the orthographic lexicon that feeds forward to the phonological lexicon and primes phonemes in the phoneme system. Second, when naming words the presence/absence of an effect of N on the Letter Units through feedback from the lexical level depends on the parameter settings. Implications and suggestions for future directions are made. (PsycINFO Database Record (c) 2010 APA, all rights reserved)