Free convection within a vertical,rectangular cavity subjected to large temperature differences

Two-dimensional temperature distributions and vortex patterns in air at atmospheric pressure contained within vertical plane walled cavities have been predicted using a finite-difference approach without encountering any instability of the solution procedure. Appropriate allowances have been made in this procedure for the temperature dependence of the air properties. The predictions are in good agreement with experimental observations.     

Linguistic and location effects in compliance with pesticide warning labels for amateur and professional users

Three studies explored amateur and professional users' compliance with pesticide warning labels. Professionals were classified as people working in a profession in which the use of pesticides is a necessary part of their job. Amateurs used pesticides only in their leisure time. The first study showed that the wording used affected perception of the appropriateness of hazard statements, one of the most effective variations being the use of the personal pronoun (statements beginning "You should..."). The location of warning information was also found to affect actual compliance: Compliance increased when warning information was presented in the directions for use section. A supplemental directive increased compliance only for professional users. In a final study, "best-case" and "worst-case" linguistic variations were combined with best-case and worst-case locations for safety information. Instruction statements using the personal pronoun and presented in the directions for use section resulted in the highest levels of compliance. The differences in compliance between amateur and professional users are interpreted within the framework of Rasmussen's (1986) distinction among skill-, rule-, and knowledge-based behavior. Actual or potential applications of this research include the design of warning labels and safety information.     

Using Distributed Computers to Deterministically Approximate Higher Dimensional Convection Diffusion Equations

A new approach to solving D> 3 spatial dimensional convection-diffusion equation on clusters of workstations is derived by exploiting the stability and scalability of the combination of a generalized D dimensional high-order compact (HOC) implicit finite difference scheme and parallelized GMRES(m). We then consider its application to multifactor Option pricing using the Black–Scholes equation and further show that an isotropic fourth order compact difference scheme is numerically stable and determine conditions under which its coefficient matrix is positive definite. The performance of GMRES(m) on distributed computers is limited by the inter-processor communication required by the matrix-vector multiplication. It is shown that the compact scheme requires approximately half the number of communications as a non-compact difference scheme of the same order of truncation error. As the dimensionality is increased, the ratio of computation that can be overlapped with communication also increases. CPU times and parallel efficiency graphs for single time step approximation of up to a 7D HOC scheme on 16 processors confirm the numerical stability constraint and demonstrate improved parallel scalability over non-compact difference schemes.     

Phase retrieval from subdivision of the focal plane with a lenslet array

A phase retrieval algorithm derived from subdivision of the complex field at the focal plane is proposed. This subdivision is achieved with a lenslet array at the focal plane in a manner similar to the pyramid wave-front sensor. The phase retrieval algorithm significantly improves the wave-front estimate that can be attained as a linear combination of the aperture images. This phase retrieval algorithm also avoids the twin-image stagnation problem inherent in phase retrieval and phase retrieval in conjunction with the Shack-Hartmann sensor.     

The characterization and functional reliability of 45 Mbit/s optical transmitters containing MBE-grown lasers

We have characterized the performance and studied the functional reliability of 45 Mbit/s lightwave transmitters containing proton-bombarded stripe lasers grown in a research environment by molecular beam epitaxy (MBE). We observe that these transmitters have superior performance compared to transmitters containing lasers of similar geometry grown in production facilities by liquid phase epitaxy (LPE), and subsequently processed using the same technology. The reliability data of over 10 000 h indicate that the functional lifetime of the MBE lasers will be limited ultimately by extinction ratio degradation in our circuit strategy. The origin of the degradation is the increase of the spontaneous light at the bias current.     

Resonance Raman spectroscopy of photolabile transition metal carbonyls: controlled photoalteration with continuous wave lasers to record spectra of reactants or transient species

A method has been developed that enables resonance Raman spectra of photolabile species in solution to be recorded under conditions where the level of photoalteration is controlled: a low level enables reactant spectra to be recorded, whereas a high level enables the spectra of short-lived transient species to be recorded in real time using continuous-wave (CW) lasers and standard Raman detection equipment. The design includes a sealed flow system, enabling air-sensitive species to be studied under an inert atmosphere. A simple theoretical model has been developed to aid the interpretation of experimental results, and its applicability is demonstrated. Controlled photoalteration and its theory are demonstrated with 413.1-nm excitation of carbonmonoxymyoglobin (MbCO), which generates deoxymyoglobin (deoxy-Mb) on photolysis, and for which the spectra of both species are well established. The methods have also been applied to two air-sensitive, photolabile transition metal carbonyls using 514.5-nm wavelength excitation: for Cp2Mo2(CO)6 (Cp = eta5-C5H5), increasing levels of photoalteration result only in a decrease in the parent band intensities, relative to the solvent bands; for Cp2Fe2(CO)4, increasing levels of photoalteration result in the appearance of additional bands that are assigned to the transient species CpFe(mu-CO)3FeCp, formed following the loss of a CO ligand.     

Longitudinal associations between hostility in adolescents' family relationships and friendships and hostility in their romantic relationships.

This study examined longitudinal predictors of hostility in adolescents' romantic relationships. The sample included 110 adolescents and their parents from 72 families. Observational measures of parents' marital hostility and parent-child hostility and self-reports of hostility in close friendships were collected when adolescents ranged from 14 to 16 years old. Three years later, when they were 17 to 19 years old, adolescents reported on the hostility in their romantic relationships. Results indicated that hostility in parents' marital relationships and in adolescents' friendships accounted for independent variance in hostility in adolescents' later romantic relationships. Results highlight the importance of both family relationships and friendships for predicting hostility in adolescents' romantic relationships over time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Light flicker test in the United States

Home appliances, like washers, dryers, refrigerators, etc., can cause voltage fluctuations and light flicker. A standardized flicker test has been established in Europe (IEC 1000-3-3). However, the European test is designed for 230-V 50-Hz power and needs to be modified for a 115-V 60-Hz supply. In this paper, the reference impedance and the limits of flicker tests for 115 V/60 Hz systems are proposed. A high-performance power analysis system, the Xitron 2803AH power analyzer, was used to study the voltage fluctuations and flicker caused by some washing machines. The analysis and test results provided in this paper can serve as a proposal for establishing a US light flicker testing standard for 115 V/60 Hz     

Vocal learning in the grey parrot (Psittacus erithacus): Effects of species identity and number of trainers.

Grey parrots (Psittacus erithacus) learn referential English labels when they view and interact with 2 humans who model vocal labeling and who demonstrate referentiality and functionality of a label (I. M. Pepperberg, 1990a). To test if both trainers are necessary, the authors contrasted 2-trainer modeling with training by 1 human who presented targeted labels to a bird in concert with appropriate items, who asked questions, and who would reward attempts at the label with the item. The bird was also tutored by either 1 or 2 interactive humans in conjunction with a conspecific who already used referential labels. Referential labels were learned from multiple live tutors but not a single trainer. Presence of a conspecific enhanced learning compared with single-trainer sessions but did not affect acquisition in 2-human sessions. Specific aspects of paired tutoring seem critical for acquiring referential vocal labels. (PsycINFO Database Record (c) 2010 APA, all rights reserved)