Degradation action of water on S-glass

Glass fiber reinforced composites have been used to an increasing extent as structural components because of their high strength at relatively low densities. They are more resistant to moisture and weathering than most other structural materials. However, under environments of high humidity and temperature, glass fiber composites with an epoxy or polyester matrix lose a considerable fraction of their.strength- after a relatively short time. For high strength glass reinforced composites, the glass filaments are mostly of the S-glass and E-glass types. This investigation reports the solvent effect of water on S-glass rovings (filament strands) and powders. S-glass is the strongest silicate glass developed in the past decade, the composition of which in weight percent is: A1₂O₃/MgO/SiO₂ = 25/10/65. In the temperature range covered (30 to 50°C), analyses of aluminum, magnesium, and silicon in water after different time periods indicate that magnesium is preferentially leached out of S-glass, either as filaments or as powders, by water. The concentrations of magnesium and silicon in the water reached 2 mg/litre or more depending on the temperature and length of contact time, while the aluminum concentration reached no more than 0.2 mg/litre. Decomposition products of the ingredients present in a composite, including the coupling and curing agents, could further complicate the degradation process. Rate relations are proposed and discussed based on the dissolution data.     

Fracture of single crystals of the nickel-base superalloy PWA 1480E in helium at 22 °C

The fracture behavior of single crystals of the PWA 1480E nickel-base superalloy was studied using both scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. Notched single crystals with seven different crystal growth orientations near [100], [110], [111], [013], [112], [123], and [223] were tensile tested at 22 °C in a helium atmosphere at 34 MPa. Gamma prime particles were orderly and closely aligned with the cube edges along the [100], [010], and [001] directions of theγ matrix. The cuboid morphology of theγ’ precipitate was not influenced by the crystal growth orientation. The specimen with the [110] orientation was the strongest, while the crystal with the [100] orientation was the weakest. A stereoscopic technique, combined with the use of planary’ morphologies, was applied to identify the cleavage plane orientation. All specimens failed predominately by {lll}-type cleavage which originated from combined slip on various {111} planes. In most cases, deformation was found to occur inhomogeneously in intense slip bands lying on {111} planes and aligned parallel to the different slip directions. Both SEM and TEM studies indicated that {lll}-type slip was the controlling factor during cleavage fracture of single crystals of the PWA 1480E nickel-base superalloy. Formerly Graduate Student, Auburn University     

Genetic alteration of soybean oil composition by a chemical mutagen

Soybean (Glycine max [L.] Merr. cv. Century) seeds were treated with ethylmethanesulfonate (EMS) and the M₂ progeny were evaluated for fatty acid composition of the oil. Treatment with EMS significantly increased the variability in content of each of the fatty acids in comparison with those of the Century control. There was a strong inverse relationship between oleic and linoleic acids among seeds from M₂ plants. This supports the hypothesis of sequential desaturation as the method of formation of unsaturated fatty acids in soybean oil. A genetically stable mutant with 3.4% linolenic acid was identified that was similar to the cultivar Century in days to maturity, plant height and resistance to lodging. Contribution of the Agricultural Research Service, US Department of Agriculture and the Purdue Agriculture Experiment Station. Published as Journal Paper No. 9510 of the Purdue Agriculture Experiment Station, USDA-ARS, Purdue University and the Northern Regional Research Center, ARS, USDA, Peoria, IL 61604.     

Changes in family law and family life: Challenges for psychology.

In the past two decades, striking changes in family demographics have been accompanied by equally dramatic shifts in family law. The development of constitutional principles to guide state involvement in the lives of children and families has raised questions about the competence of minors and the sensitivity of parents to children's interests. At the same time, legal realism finally has emerged as an approach to the construction of new standards for resolution of family disputes and new definitions of the family itself. These changes in family law present new challenges to psychology to generate and diffuse the knowledge necessary for careful policy-making. Care must be taken, though, to ensure that legitimate limits of role and expertise are acknowledged and respected. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Free convection about a rectangular prismatic crystal growing from a solution

Sodium chlorate crystals growing from unstirred aqueous solutions were observed by schlieren techniques. Growth rate data were best correlated by Sh = 0.48 Ra^0.25 with finite interface kinetics and a characteristic length L equal to the crystal height plus the inverse reciprocal sum of the horizontal dimensions. The growth rate was slightly higher when the plume was laminar than when it was irregular. The horizontal growth rate was greater than the vertical growth rate, with the ratio tending to decrease with increasing plume instability. The threshold Grashof number for plume instability was greatly decreased with decreasing height for crystals with the same horizontal dimensions. The frequency of eddy emission was proportional to L⁻²Ra^0.8. The velocity of the eddies approached a constant value with increasing distance above the crystal surface, the terminal value being roughly proportional to Ra^1/2/L.     

Effects of variations in the preparatory interval on the reaction time of retardates and normals.

Conducted 2 studies to evaluate the effects, on simple RTs, of warning signal duration (WSD) and preparatory interval (PI) with normal and mentally retarded Ss. In Exp. I PIs of 2, 4, 8, and 12 sec. were presented in an unpredictable sequence. For 1/2 of the Ss the warning signal remained on throughout the entire PI (filled condition) and for the remainder of the Ss, the warning signal was present for only 1.5 sec. of the PI. Significant effects of intelligence, PI, and WSD were found. The interaction Intelligence * PI was also significant. The unfilled condition resulted from produced faster RTs for both normals and retardates. The interaction resulted from the particularly poor performance of the retardates at the short PIs. Exp. II employed a 1.5 sec WSD with PIs of 2, 4, 8, 16, and 32 sec. An interaction was found involving intelligence and PI. Results are discussed in terms of temporal uncertainty. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Plasma progestins, estradiol, and luteinizing hormone following prostaglandin F2 alpha injection

Dairy animals, ranging from days 8 to 13 of the estrous cycle, were fitted with indwelling jugular catheters 1 day prior to either intramuscular injection of prostaglandin F2alpha free acid (30 mg, n=4) or intrauterine deposition of prostaglandin F2alpha free acid (10 mg, n = 3). Blood samples were collected at 6, 4, 2, and 0 h prior to administration of prostaglandin F2alpha and at 1, 3, and every 2 h thereafter until ovulation. Progestins, estradiol, and luteinizing hormone in plasma were measured by radioimmunoassay. Hormonal changes and interrelationships within animals were evaluated by least squares analyses. Decreases in progestins of plasma within 24 h indicated prostaglandin F2alpha induced luteolysis in six of the seven animals. Estradiol increased linearly from time of injection to 52 h postinjection. Intervals from administration of prostaglandin to onset of estrus, peak of luteinizing hormone, and ovulation were 74.9 +/- 21, 78.8 +/- 21, and 99.5 +/- 19 h.