Effect of precyclic loading on stress-corrosion-cracking initiation in an X-65 pipeline steel exposed to near-neutral pH soil environment

A study was carried out to understand the effect of precyclic loading on stress-corrosion-crack initiation in an X-65 pipeline steel exposed to a near-neutral-pH soil environment. The test specimens were precyclically loaded before corrosion exposure to represent a service history of up to about 20 years, depending on the severity of pressure fluctuation. Microcracks had initiated on the polished surface of the X-65 pipeline steel after long-time exposure at open-circuit potential (OCP) in a near-neutral-pH synthetic soil solution. These microcracks were mostly initiated from pits at metallurgical discontinuities such as grain boundaries, pearlitic colonies, and banded phases in the steel. Strong preferential dissolution was observed along planes of the banded structures in the steel. The selective corrosion attack at these metallurgical discontinuities is attributed to the galvanic nature of those areas to their neighbors. Cyclic loading prior to corrosion exposure had significant effects on microcrack initiation and propagation during subsequent corrosion exposure. Cyclic loading prior to corrosion exposure either reduced or increased the probability of crack initiation and the rate of crack propagation, depending upon the magnitude of the stress cycles. The largest reduction was seen at a peak cyclic stress of about 0.8 of the yield strength. This cyclic-loading-dependent cracking behavior might be related to the alteration of the substructures and the residual stress in the steel as a result of precyclic loading.     

Microsatellite instability in follicle centre cell lymphoma

Fluorescent polymerase chain reaction (PCR) was used to assay 12 microsatellite markers (APC x 2, DCC, P53 x 2, RB1, NM23, WT1, D6S260, D6S262, D6S281 and TNFa) to look for evidence of microsatellite instability in 40 cases of follicle centre cell lymphoma (FCC). Evidence of novel alleles seen in the tumour tissue but not the normal uninvolved tissue was seen in seven cases (17%). In only two of these cases (5%) was more than one locus involved but in these cases multiple affected loci were seen (4/12 and 7/12 respectively). The detection of microsatellite instability indicates a DNA repair defect such as that which would be predicted to occur in cells with mutated mismatch repair genes, a novel finding in FCC lymphoma.     

Medication status of participants in psychopathology research: Selective review of current reporting practices.

The majority of Ss included in studies of psychopathology are typically receiving psychoactive medication. In view of concerns regarding the confounding effects of psychoactive medication, it appears that researchers should provide information regarding at least the drug status of the Ss studied. A review of the articles on adult psychopathology that appeared in the Journal of Abnormal Psychology during a 5-yr period, however, revealed that nearly 50% of reports on Ss presumably receiving psychoactive medications failed to specify the medication status of those Ss. Few studies (15%) provided adequate information regarding the types and dosages of psychoactive drugs received by the Ss. It is argued that researchers should provide a full report of the psychoactive drugs received by research participants and, when participants are unmedicated, to indicate the reasons for drug-free status. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A quantum-well-intermixing process for wavelength-agile photonic integrated circuits

Wavelength-agile photonic integrated circuits are fabricated using a one-step ion implantation quantum-well intermixing process. In this paper, we discuss, the issues in processing optimized widely tunable multisection lasers using this technique and present the results achieved using this process. This quantum-well intermixing process is general in its application and can be used to monolithically integrate a wide variety of optoelectronic components with widely tunable lasers.     

Recovery from work shifts: How long does it take?

Although regulations on work hours usually include a minimum weekly rest period, there is little empirical evidence concerning recovery from work. Shift-working nurses (N?=?61) used a handheld computer for 28 days to complete self-ratings, cognitive-performance tasks, and a sleep diary. Many measures were worse on rest days that followed a night shift rather than a day shift and tended to be worse on 1st rest days compared with subsequent rest days. Alertness was lowest on the 1st rest day following a night shift. Social satisfaction was better on workdays that were preceded by 2 rather than 1 rest day. Reaction time (RT) decreased over consecutive night shifts and tended to increase over rest days following night shifts. The results are interpreted as being consistent with the combined adaptive costs of fatigue and adjustment to and from a nocturnal routine. The practical implications for scheduling rest days are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Narrow pulse measurement of drain characteristics of GaAs MESFETs

A measurement technique is presented which uses narrow, fast-rise-time pulses applied to both the gate and the drain of a GaAs MESFET to obtain the drain characteristics of the device. This allows the characteristics of the device to be obtained which correspond to frequencies above those at which surface and substrate traps can respond. The resulting characteristics show significant departures from those obtained using conventional long pulse and DC measurement techniques.     

Formant labelling using pole-focused spectra

An algorithm is introduced which labels formants from the peaks of pole-focused spectra. A clustering procedure is first used to produce line segments of possible formants. These can be considered as anchor traces for the later processing. Rule-based labelling is then applied to provide final formant trace estimates. Experimental results show that the proposed algorithm offers improved formant labelling accuracy.     

FTIR-ATR studies of diffusion and perturbation of water in polyelectrolyte thin films. Part 4. Diffusion, perturbation and swelling processes for ionic solutions in SPEES/PES membranes

We report diffusion rates and equilibrium concentrations of water in a polyelectrolyte SPEES/PES film using ATR/FTIR spectroscopy. The data for water obtained by fitting spectral intensities to a dual mode diffusion model in the presence of different counter ions (at 0.2 mol dm⁻³) follow the order Li⁺>Cs⁺>Na⁺>Ca²⁺>K⁺. Diffusion is progressively slower for higher concentrations of NaCl (0.2-0.85 mol dm⁻³) and the NO₃⁻ counter anion leads to a faster diffusion rate than for Cl⁻ at the same concentration. Both water uptake and diffusion rates are broadly consistent with expectations based on the differential degrees of swelling, caused by changes in the SO₃⁻/SO₃⁻ interpolymer chain repulsive forces leading to a decrease in volume diffusion compared with the value for pure water. Direct spectral measurements of the degree of swelling confirm that the process does occur, although the order of the swelling amounts does not map directly onto that of the diffusion rates. This is probably because the interfacial dissociation processes are hydration dependent.