The use of residuals in statistical modeling for fatigue-crackgrowth under constant amplitude loading

Various models have been proposed over the years to fit crack growth data. Many papers have appeared in which one or more models are mooted and fitted, and various assessments made of the quality of the fit. At the basic level the data are plotted, together with the fitted curve, to show agreement of experimental and predicted values. In this paper we suggest that it can be useful and informative to go one step further, examining the residuals, i.e., the differences between the experimental and predicted values. We draw attention to certain statistical methods for such critical assessment and show by example that this can reveal deficiencies in fit not otherwise obvious. In this way suitable modifications to the model can be suggested. Additional plots of estimated parameters are also shown to be informative about models     

X-ray topography studies of dislocations in single crystal CVD diamond

X-ray topography has been used to study single crystal diamond samples homoepitaxially grown by microwave plasma-assisted chemical vapour deposition (CVD) on high pressure high temperature (HPHT) and CVD synthetic diamond substrates. Clusters of dislocations in the CVD diamond layers emanated from points at or near the interface with the substrate. The Burgers vectors of observed dislocations have been determined from sets of {111} projection topographs. Dislocations have line directions close to the [001] growth direction and are either edge or 45° mixed dislocations. Where groups of dislocations originated at isolated points they tended to be of the edge variety. Where the substrate surface was deliberately damaged before growth, two sets of dislocations were observed to have propagated from each line of damage and there was a tendency for dislocations to be of the 45° mixed variety with a component of their Burgers vector parallel to the polishing direction. It is demonstrated that X-ray topography can be used to deduce the growth history of CVD synthetic diamond samples produced in multiple growth stages.     

Arsenic deactivation enhanced diffusion and the reverseshort-channel effect

The effect of enhanced diffusion caused by the electrical deactivation of arsenic on the reverse short-channel effect (RSCE) in NMOS devices is investigated. A simple four-mask process was utilized to fabricate deep sub-micron NMOS devices. Source/drain (S/D) implant and anneal conditions were varied in order to determine their implications on the RSCE. Results indicate that when high concentrations of arsenic deactivate, enhanced diffusion occurs, leading to significantly more RSCE. This implies that the dose of the arsenic implant and the subsequent anneals should be carefully considered in source/drain engineering     

Determination of Filter Pore Size for Use in HB Line Phase II Production of Plutonium Oxide

The Savannah River Site’s H-Canyon and HB-Line are tasked with the production of plutonium oxide from a feed of plutonium metal for the Mixed Oxide (MOX) Fuel Fabrication Facility. The work presented here followed the general precipitation methods used at SRS to determine the quantity of solids present in the filtrate and to recommend an alternate filtration strategy. Initial Pu losses were found to be less than 1.5%. With additional filtration, this study indicates that a 50% further reduction in Pu solids in the filtrate can be achieved by the addition of a 2 μm filter.     

Memory for serial position: Effects of spacing, vocalization, and stimulus suffixes.

Several theorists have argued that the magnitude of recency effects in recall reflects the clarity of temporal-order information in memory. Six experiments tested this proposal by observing the effects of three variables (interitem spacing, vocalization, and stimulus suffixes) that can influence the magnitude of the recency effect on memory for serial position. Spacing had no beneficial effects on memory for position. Vocalization benefited memory for position but only at the beginning and end of a list. Stimulus suffixes interfered with memory for position only at the end of a list. The entire pattern of results cannot be explained by temporal-coding accounts of the recency effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Complex impedance measurements of calorimeters and bolometers: correction for stray impedances

Impedance measurements provide a useful probe of the physics of bolometers and calorimeters. We describe a method for measuring the complex impedance of these devices. In previous work, stray impedances and readout electronics of the measurement apparatus have resulted in artifacts in the impedance data. The technique allows experimenters to find an independent Thevenin or Norton equivalent circuit for each frequency. This method allows experimenters to easily isolate the device impedance from the effects of parasitic impedances and frequency dependent gains in amplifiers.     

Investigation of Dipicolinic Acid Isosteres for the Inhibition of Metallo-β-Lactamases

New Delhi metallo-β-lactamase-1 (NDM-1) poses an immediate threat to our most effective and widely prescribed drugs, the β-lactam-containing class of antibiotics. There are no clinically relevant inhibitors to combat NDM-1, despite significant efforts toward their development. Inhibitors that use a carboxylic acid motif for binding the Zn^II ions in the active site of NDM-1 make up a large portion of the >500 inhibitors reported to date. New and structurally diverse scaffolds for inhibitor development are needed urgently. Herein we report the isosteric replacement of one carboxylate group of dipicolinic acid (DPA) to obtain DPA isosteres with good inhibitory activity against NDM-1 (and related metallo-β-lactamases, IMP-1 and VIM-2). It was determined that the choice of carboxylate isostere influences both the potency of NDM-1 inhibition and the mechanism of action. Additionally, we show that an isostere with a metal-stripping mechanism can be re-engineered into an inhibitor that favors ternary complex formation. This work provides a roadmap for future isosteric replacement of routinely used metal binding motifs (i.e., carboxylic acids) for the generation of new entities in NDM-1 inhibitor design and development.     

Imagery for musical timbre.

Subjects made same/different judgments concerning the pitches of two successive tones. In Experiment 1, the two tones were played on either the same instrument (guitar, flute, trumpet) or on different instruments. When the two pitches were indeed the same, people were faster to respond "same" when the instrumental timbres also matched than when two different instruments played the tones. In Experiment 2, the first tone was always a sine wave and the second was one of the same three instrumental tones. Following the sine wave, but before presentation of the second tone, people were asked to form an image of what an assigned instrument would have sounded like playing that pitch. A match between this imagined timbre of the first tone and the timbre of the second tone produced faster reaction times to identical pitches than a mismatch. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Vibrational analysis of high-energy compounds: 1-nitroso-3,3-dinitroazetidine

Abstract

Infrared spectra were obtained and normal coordinate calculations were made for 1-nitroso-3,3-dinitroazetidine (NO-DNAZ) in order to make assignments of the infrared bands to the appropriate normal modes of vibration. Only one stable conformation was found by semi-empirical molecular orbital calculations. Appropriate force constants that had been obtained for TNAZ were used as starting values for NO-DNAZ. The transferability of the force constants was quite good, so they should be useful in calculations for other dinitroazetidines. Force constant refinements resulted in calculated vibrational wavenumbers that differed from observed values by an average of only 1.9 cm^?1.     

Quantum information processing in the neighborhood of a black hole

Natural Computing - Using an imperfectly prepared state, we show that in relativistic settings, the evolution of a massive spin-1/2 particle violates many standard assumptions made in quantum...