Austempered Materials for Powertrain Applications

Austempered irons and steels offer the design engineer alternatives to conventional material/process combinations. Depending on the material and the application, Austempering may provide the following benefits to producers of powertrain components such as gears and shafts: ease of manufacturing, increased bending and/or contact fatigue strength, better wear resistance and enhanced dampening characteristics resulting in lower noise. Austempered materials have been used to improve the performance of powertrain components in numerous applications for a wide range of industries, from gears and shafts to clutch plates and crankshafts. This paper focuses on Austempered solutions for powertrain applications with an emphasis on gear and shaft solutions.     

Decadal trends of silver and lead contamination in San Francisco Bay surface waters

Over the past decade, San Francisco Bay surface waters have remained enriched with dissolved (<0.45 microm) silver and lead concentrations (decadal means of 5.7 ng kg(-1) Ag[filtered] and 31 ng kg(-1) Pb[filtered]) compared with those (0.26 ng kg(-1) Ag[filtered] and 2.7 ng kg(-1) Pb[filtered]) of adjacent oceanic surface waters of the northeast Pacific, despite efforts to reduce pollutant loadings to the Bay during that period. While time series models show that there has been a 40% decline in total lead concentrations in the southern reach of the estuarine system between 1989 and 1999, the filtered lead fraction has not changed significantly during that time. That persistence is attributed to (i) the ongoing input from previous atmospheric depositions and industrial lead to its drainage basin, which are slowly being advected into the estuary and (ii) the internal recycling of lead between the surface sediments and the water column within the Bay. In contrast, both filtered and total silver concentrations in the southern reach have declined by 70% and 40%, respectively, within the past decade. These temporal declines are attributed to a 2-fold decrease in silver loadings from publicly owned treatment works and a comparable decline in the silver concentration of surficial sediments within that region during the past decade. In the northern reach, silver and lead concentrations have remained essentially constant between 1989 and 1999, reflecting invariable anthropogenic input of these elements to this embayment over that decade.     

An NMR shielding model for protons above the plane of a carbonyl group

Covalently bonded hydrogen nuclei located over the plane of a carbonyl group in a strong magnetic field experience magnetic shielding (or deshielding) that results from the combined effect of the magnetic anisotropy of the carbon-oxygen double bond and various other intramolecular shielding effects. GIAO-HF in Gaussian 98 was employed to calculate isotropic shielding values and to predict the net proton NMR shielding increment for a simple model system: the proximate proton of methane held in various positions over formaldehyde. The net shielding increments of the proximate proton of methane, plotted against its Cartesian coordinates relative to the center of the carbon-oxygen double bond, led to the development of a single empirical equation for predicting the NMR shielding experienced by a covalently bonded proton over the plane of a carbonyl group. The predictive capability of this equation has been validated by calculating the shielding increments of protons over the plane of a carbonyl group in known structures, using this as a correction to the chemical shift estimated by subtituent effects and comparing the result to experimentally observed chemical shifts. Shielding is predicted by this equation for protons located in the region from over the center of the carbon-oxygen double bond to beyond the carbon atom; deshielding is predicted for protons located above and beyond the oxygen atom. This prediction differs from those made by the long-held "shielding cone" model found in nearly every textbook on NMR, but is consistent with experimental observations. The algorithm for predicting the shielding increment for a proton over a carbonyl group can be used in a spreadsheet or incorporated into software that estimates chemical shifts using additive substituent constants or a database of structures. Its use can improve the accuracy of the estimated chemical shift of a proton in the vicinity of a carbon-oxygen double bond, and thus assist in spectral assignments and in correct structure determination.     

Supercritical fluid generated stationary phases for liquid chromatography and capillary electrochromatography

Chromatographic silica-bonded stationary phases have been prepared using supercritical CO(2) as the reaction medium. (29)Si solid-state NMR spectra of the generated bonded silica phases show unreacted silica species Q(3) and Q(4), alongside important resonances for surface-bound ligands, T(1), T(2), and T(3). Initially, a fluorinated octyl silica (C(8)) phase was produced, by reacting (1)H,(1)H,(2)H,(2)H-perfluorooctyltriethoxysilane with silica particles (3 microm) in sc-CO(2) at 60 degrees C and 450 atm for 3 h. In-house-packed LC columns of this fluorinated sc-C(8) silica phase yielded typical reversed-phase behavior when a standard test mix of benzamide (k' = 1.03), benzophenone (k' = 8.11), and biphenyl (k' = 14.92) was eluted. When packed into fused-silica capillaries for CEC, this fluorinated sc-C(8) silica phase gave linear plots of log k' versus percentage MeOH for benzophenone and biphenyl and, in contrast to octyl or octadecyl silica phases, displayed selectivity for aromatic thioureas when chromatographed among a series of synthetic organic thiourea test solutes. Similarily, an octadecyl silica phase (sc-C(18) silica) was prepared by reaction of n-octadecyltriethoxysilane in sc-CO(2), packed at 9500 psi and examined by LC. The sc-C(18) silica LC column yielded high column efficiency (up to 141 000 N/m (fluorene)) and excellent asymmetry factors (1.06, fluorene) without resource to end-capping. Following a second silylating or end-capping step using hexamethyldisilazane in sc-CO(2), sc-end-capped sc-C(18) silica phases elute N,N-DMA before toluene and the toluidine isomers as a single peak, indicating lowered silanol activity according to the Engelhardt test. A rapid separation of the important pharmaceutical substances, ketoprofen, naproxen, fentoprofen, and ibuprofen, on an sc-end-capped sc-C(18) silica phase is also shown.     

Donald G. Forgays (1926–1993): Obituary.

Memorializes D. G. Forgays, who earned an international reputation for his pioneering research on early environmental influence on psychological and physiological functioning. Forgays worked in a range of areas that included the psychophysiology of sensory deprivation and personality dimensions of addictive behaviors. Most of his projects involved cross-cultural data collection and collaboration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phenylalkenals in ponerine(Leptogenys sp.) and myrmicine (Pogonomyrmex sp.) ants

Cephalic extracts of two unrelated species of ants,Leptogenys processionalis andPogonomyrmex rugosus, have been found to contain 2-phenylpropenal and 2-phenyl-2-butenal, while two other species related to the first,L. chinensis andL. kitteli, lacked either.L. kitteli also produced a tetrasubstituted pyrazine found previously only in two New Zealand ants in the genusMesoponera. The chemical reactivity of the phenylalkenals suggests their function in repelling attack by predators.     

Unskilled and unaware--but why? A reply to Krueger and Mueller (2002).

J. Kruger and D. Dunning (1999) argued that the unskilled suffer a dual burden: Not only do they perform poorly, but their incompetence robs them of the metacognitive ability to realize it. J. Krueger and R. A. Mueller (2002) replicated these basic findings but interpreted them differently. They concluded that a combination of the better-than-average (BTA) effect and a regression artifact better explains why the unskilled are unaware. The authors of the present article respectfully disagree with this proposal and suggest that any interpretation of J. Krueger and R. A. Mueller's results is hampered because those authors used unreliable tests and inappropriate measures of relevant mediating variables. Additionally, a regression-BTA account cannot explain the experimental data reported in J. Kruger and D. Dunning or a reanalysis following the procedure suggested by J. Krueger and R. A. Mueller. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of individual versus aggregate social comparison and the presence of others on self-evaluations.

In 5 studies, the authors investigated the effects of comparison with an individual versus comparison with the statistical average on self-evaluations of performance and ability. In Studies 1 and 2, participants took a test of lie detection ability and were provided with the average score and the score of an individual coactor. Both types of feedback significantly affected self-evaluations of performance, but only comparison with the coactor significantly affected self-evaluations of ability. Studies 3 and 4 demonstrated that the presence of a coactor moderated the effect of aggregate social comparison on self-evaluations of ability. The results provide preliminary support for the contention that minimizing the impact of comparison with the average is a self-serving strategy that is facilitated by the presence of others. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Response to the discussion by I.V. Rokach of the paper entitled: “Analysis of the dynamic responses for a pre-cracked three-point bend specimen”

The following response to the discussion of the above mentioned paper is divided into two parts: (1) a response to the issue of our comparison of the apparent period of specimen oscillation, , and the natural vibration period of a cracked specimen, T, and (2) a verification of the applicability of our model to short time-to-fracture tests, which Rokach has questioned, due to a lack of knowledge of Hopkinson bar techniques.     

Nanowire dye-sensitized solar cells

Excitonic solar cells-including organic, hybrid organic-inorganic and dye-sensitized cells (DSCs)-are promising devices for inexpensive, large-scale solar energy conversion. The DSC is currently the most efficient and stable excitonic photocell. Central to this device is a thick nanoparticle film that provides a large surface area for the adsorption of light-harvesting molecules. However, nanoparticle DSCs rely on trap-limited diffusion for electron transport, a slow mechanism that can limit device efficiency, especially at longer wavelengths. Here we introduce a version of the dye-sensitized cell in which the traditional nanoparticle film is replaced by a dense array of oriented, crystalline ZnO nanowires. The nanowire anode is synthesized by mild aqueous chemistry and features a surface area up to one-fifth as large as a nanoparticle cell. The direct electrical pathways provided by the nanowires ensure the rapid collection of carriers generated throughout the device, and a full Sun efficiency of 1.5% is demonstrated, limited primarily by the surface area of the nanowire array.