Exfoliation and related microstructures in 2024 aluminum body skins on aging aircraft

Exfoliation, a directional attack along elongated grain boundaries, has been examined in some detail in rolled 2024 aluminum sheet and plate for KC-135 aging aircraft body skin samples utilizing optical (light) metallography, scanning electron microscopy, and transmission electron microscopy. A detailed analysis and comparison of precipitates within the grains and in the grain boundaries were performed, as well as an examination of elemental depletion profiles across grain boundaries. These observations suggest that corrosion-related anodic sites play a far less significant role in the propagation of exfoliation than do the hard corrosion products creating wedging stresses within the elongated grain boundaries, which seem to demonstrate unique and unusual structural or energetic features or both.     

Additional revenues recoup automated pharmacy cost

The installation of a computerized pharmacy system at Cape Fear Valley Medical Center's pharmacy has improved revenues +5.50 per patient day--a 10% increase over like figures for the previous 5 months. A system that paid for itself in just fifteen days.     

Conversion between standard and low-alpha lead in solder bumping production lines

Soft-errors caused by lead in solder-bumping have been a concern for many years. The problem is of special concern for high-density interconnection applications requiring solder to be placed directly over active circuitry. In that situation, alpha particles emitted by radioactive lead cause soft-errors with no possibility of shielding circuitry. For optimal cost-effectiveness, though, not all solder bumped wafers require low-alpha lead. MCNC has developed a solder bumping facility with both a research branch at MCNC and a full-scale production facility at its spin-off, Unitive Electronics Inc. We present results here of our work in incorporating low-alpha lead as part of our solder bumping process. We describe the amount of cross-contamination measured when alternating plating baths of regular lead and low-alpha lead.     

Questionnaire design, return rates, and response favorableness in an employee attitude questionnaire.

Topic order and location of demographic items were systematically varied in an employee attitude survey distributed to 1,188 office personnel of a single organization. With six questionnaire topic areas arranged in the order that matched employee representatives' perceptions of employee priorities, returns were higher (96%) than with any of five random orders (average 78%). Returns were higher with demographic items placed at the end (85%) than at the beginning (77%). Global attitudes and three of six topic attitudes varied with topic order and were more positive with the prioritized topic order than with the five random orders. The largest order effect was noted in employees' attitudes toward pay, which was the most important topic. Methodological and practical implications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Solid-state spun fibers and yarns from 1-mm long carbon nanotube forests synthesized by water-assisted chemical vapor deposition

We report continuous carbon nanotube (CNT) fibers and yarns dry-drawn directly from water-assisted chemical vapor deposition (CVD) grown forests with about 1-mm height. As-drawn CNT fibers exist as aerogel and can be transformed into more compact fibers through twisting or densification with a volatile organic liquid. CNT fibers are characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, Raman microscopy, and wide-angle X-ray diffraction. Mechanical properties and electrical conductivity of the post-treated CNT fibers are investigated. The resulting fibers show the work of rupture of 30 J/g and DC electrical conductivity of 5.0 × 10⁴ S/m.     

The design of mosaic armour: The influence of tile size on ballistic performance

Silicon carbide square tiles of different areal geometries and manufactured via two different processing routes have been bonded to polycarbonate layers to evaluate their ballistic performance. Four ceramic tile sizes were tested: 85 mm, 60 mm, 50 mm and 33 mm. In each case the residual depth-of-penetration into a polycarbonate semi-infinite backing was recorded. To elucidate the penetration and failure mechanisms, a computational model using the JH-1 ceramic model [Holmquist TJ, Johnson GR. Response of silicon carbide to high velocity impact. J Appl Phys 2002;91:5858–66] of the projectile used in the experimental study penetrating into a silicon carbide-faced polycarbonate was implemented in the hydrocode AUTODYN-2D. This paper shows that there is a critical dimension of tile that should be used in a silicon carbide-based ceramic-faced mosaic armour system design to ensure optimum system performance when each tile is struck centrally.     

The Development of Color Categories in Two Languages: A Longitudinal Study.

This study unites investigations into the linguistic relativity of color categories with research on children's category acquisition. Naming, comprehension, and memory for colors were tracked in 2 populations over a 3-year period. Children from a seminomadic equatorial African culture, whose language contains 5 color terms, were compared with a group of English children. Despite differences in visual environment, language, and education, they showed similar patterns of term acquisition. Both groups acquired color vocabulary slowly and with great individual variation. Those knowing no color terms made recognition errors based on perceptual distance, and the influence of naming on memory increased with age. An initial perceptually driven color continuum appears to be progressively organized into sets appropriate to each culture and language. (PsycINFO Database Record (c) 2010 APA, all rights reserved)