NiTi and NiTi-TiC composites: Part 1. transformation and thermal cycling behavior

The transformation behavior of titanium-rich NiTi containing 0 vol pet, 10 vol pct, and 20 vol pct equiaxed TiC particles was studied by differential scanning calorimetry. The thermoelastic phase transformation of the unreinforced matrix exhibits multiple steps. Upon multiple transformation cycles, the rhombohedral phase (R phase) appears and all transformation temperatures decrease. The TiC particles inhibit the R phase and also lower some of the transformation temperatures. These effects can be explained by the internal misfit stresses resulting from both thermal expansion and transformation mismatch between matrix and reinforcement. The measured transformation enthalpy of bulk and reinforced NiTi is discussed in light of a thermodynamical model, taking into account the elastic energy stored upon cycling. The model indicates that a significant fraction of the matrix is stabilized and thus does not contribute to the transformation enthalpy. Formerly Postdoctoral Fellow, Department of Materials Science and Engineering, Massachusetts Institute of Technology.     

Work-parenting linkages among dual-earner couples at the transition to parenthood.

This study evaluates the impact of work experiences on parenting quality during the transition to parenthood. Dual-earner parents (n = 83) completed measures of work experiences (autonomy and interpersonal atmosphere). Parenting was observed twice, 3 months apart. Hierarchical regression analyses showed that mothers who reported a more negative interpersonal atmosphere at work showed decreases in positive parenting and increases in negative personal parenting over time, after controlling for their occupational status and general well-being. Mothers' work experiences also predicted changes in fathers' observed parenting. In contrast, fathers' work experiences were largely unrelated to fathers' or mothers' parenting. With one exception, parents' occupational status did not moderate work-parenting relationships, and feelings of role overload did not mediate these relationships. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensitivity to time change: The role of context and skill.

Three experiments used a 2-alterative, forced-choice procedure to examine the performance of skilled (musician) and unskilled (nonmusician) participants in detecting small time changes embedded within the test cycles of rhythmical patterns. Relational versus statistical properties of rhythms as well as rate and magnitude of to-be-detected time changes were varied in Experiments 1 and 2. Experiment 3 continued to vary structural properties of sequences (relational vs. statistical) and of experimental sessions. In general, listeners were better with relationally simple than with complex patterns in spite of the fact that the former were, on average, more variable; in addition, musicians were superior to nonmusicians only with simple sequences. In Experiment 3, more marked effects of relational structure within both pattens and sessions were evident. Results were interpreted in terms of an oscillator model of dynamic attending. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Honey-Bees Mating Optimization (HBMO) Algorithm: A New Heuristic Approach for Water Resources Optimization

Over the last decade, evolutionary and meta-heuristic algorithms have been extensively used as search and optimization tools in various problem domains, including science, commerce, and engineering. Their broad applicability, ease of use, and global perspective may be considered as the primary reason for their success. The honey-bees mating process may also be considered as a typical swarm-based approach to optimization, in which the search algorithm is inspired by the process of real honey-bees mating. In this paper, the honey-bees mating optimization algorithm (HBMO) is presented and tested with few benchmark examples consisting of highly non-linear constrained and/or unconstrained real-valued mathematical models. The performance of the algorithm is quite comparable with the results of the well-developed genetic algorithm. The HBMO algorithm is also applied to the operation of a single reservoir with 60 periods with the objective of minimizing the total square deviation from target demands. Results obtained are promising and compare well with the results of other well-known heuristic approaches.     

Evaporation performance of a new plate‐type heat exchanger with winding tubes on plate surfaces (estimation of performance of the heat exchanger)

A method for evaluating and predicting the performance of a newly developed plate‐type heat exchanger as an evaporator for water‐refrigerant systems such as chillers has been developed. The main component of the developed heat exchanger consists of plates packed together in a casing with winding tubes connected to both sides of the plates. Refrigerant flows inside the tubes, and water flows in the space between the plates. A herringbone‐like pattern is formed in this space by the cross sections of the winding tubes. The newly developed method estimates evaporation performance of the developed heat exchanger using new empirical correlations. There are correlations for heat transfer and pressure drop in winding‐tube banks on the water side, and correlation for the pressure drop on the refrigerant side. © 2004 Wiley Periodicals, Inc. Heat Trans Asian Res, 33(4): 245–257, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20009     

Effects of High Irradiance and Low Water Temperature on Photoinhibition and Repair of Photosystems in Marimo (Aegagropila linnaei) in Lake Akan,Japan

The green alga Aegagropila linnaei often forms spherical aggregates called “marimo” in Lake Akan in Japan. In winter, marimo are exposed to low water temperatures at 1–4 °C but protected from strong sunlight by ice coverage, which may disappear due to global warming. In this study, photoinhibition in marimo was examined at 2 °C using chlorophyll fluorescence and 830 nm absorption. Filamentous cells of A. linnaei dissected from marimo were exposed to strong light at 2 °C. Photosystem II (PSII) was markedly photoinhibited, while photosystem I was unaffected. When the cells with PSII damaged by the 4 h treatment were subsequently illuminated with moderate repair light at 2 °C, the maximal efficiency of PSII was recovered to the level before photoinhibition. However, after the longer photoinhibitory treatments, PSII efficiency did not recover by the repair light. When the cells were exposed to simulated diurnal light for 12 h per day, which was more ecological, the cells died within a few days. Our results showed new findings of the PSII repair at 2 °C and serious damage at the cellular level from prolonged high-light treatments. Further, we provided a clue to what may happen to marimo in Lake Akan in the near future.     

1-Thio-beta-D-galactofuranosides: synthesis and evaluation as beta-D-galactofuranosidase inhibitors

Beta-D-galactofuranosidase is a good chemotherapeutic target for the design of inhibitors, since beta-D-galactofuranose is a constituent of important parasite glycoconjugates but is not present in the host mammals. With this aim, we have synthesized for the first time alkyl, benzyl and aryl 1-thio-beta-D-galactofuranosides by condensation of penta-O-benzoyl-alpha,beta-D-galactofuranose with the corresponding thiols, in the presence of SnCl4as catalyst. The complete chemical and spectroscopical characterization of these compounds showed that the reaction was stereoselective. Debenzoylation with sodium methoxide afforded the beta-S-galactofuranosides in high yield. The thioglycosides were tested as inhibitors of the beta-D-galactofuranosidase of Penicillium fellutanum, using for the first time 4-nitrophenyl-beta-D-galactofuranoside as chromogenic substrate. The 4-aminophenyl-1-thio-beta-D-galactofuranoside, obtained by catalytic hydrogenation of the nitrophenyl derivative, was the best inhibitor being then an adequate ligand for the preparation of an affinity phase aimed at the isolation of beta-d-galactofuranosidases from different sources. Also the inhibitory activity of d-galactono-1, 4-lactone was shown.