Social skills of and social environments produced by different Holland types: A social perspective on person€nvironment fit models.

Acritical aspect of the environment in person–environment models is the nature and density of the social interactions of the members who populate the environment. Because social types solve problems through social mechanisms, it was hypothesized that they would have greatest skills in social coping and that the further the Euclidean distance (in Holland's hexagon) from social, the lower the skill level would be in these social skills. It was also hypothesized that there would be no differences among Holland types in skill level for problem-focused social skills. On the basis of an assessment of vocational interests and self-reported social skills of 134 undergraduates, these hypotheses were corroborated. Chemistry laboratory groups were qualitatively studied to describe the social interaction environment of persons with relative deficits in the social-coping skills. These chemists interacted often, enjoyed and benefited from the interactions, but constrained their social interactions to minimize the dependence on social-coping social skills. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Density Stratification Effects in Sand-Bed Rivers

In this paper the effects of density stratification in sand-bed rivers are studied by the application of a model of vertical velocity and concentration profiles, coupled through the use of a turbulence closure that retains the buoyancy terms. By making the governing equations dimensionless, it is revealed that the slope is the additional dimensionless parameter introduced by inclusion of the buoyancy terms. The primary new finding is that in general density stratification effects tend to be greater in large, low-slope rivers than in their smaller, steeper brethren. Under high flow conditions the total suspended load and size distribution of suspended sediment can be significantly affected by density stratification, and should be accounted for in any general theory of suspended transport.     

Restrictions on the singularity method applied to elasticity

The choice of which fundamental singular solutions to use as basis functions in the so-called singularity method applied to elasticity appears to be restricted by boundary condition types and region geometry. In practice, only the point load solution is consistently reliable but even it fails in certain instances when the elastic body is not a convex region and almost always when the region is not simply connected. Fortunately, all multiply connected regions can be partitioned into simply-connected (although not always convex) ones. A method for doing this is presented along with examples of fundamental solutions which do not work in the singularity method.     

Development, operation, and testing of a heuristic line balancing program for a microcomputer

This paper discusses the development, operation, and testing of a heuristic line balancing program that solves the Type I Line Balance problem using a microcomputer.

The line balancing method selected was based on previous studies that compared different line balancing techniques. The model is built primarily using the Hoffman (1963) procedure with modifications described by Gehrlein and Patterson (1975). For purposes of comparison the Rank Positional Weight technique (Helgeson and Birnie, 1961) is also included in the model.

Testing included thirty-seven different balances using problems from the literature. For each balance both Rank Positional Weight and Hoffmann solutions were obtained in the forward and reverse directions. Delay factors used for the Hoffmann balances were 0.0, 0.5, 1.0, 1.25, 1.5, and 2.0. Thus for each balance problem a total of fourteen tests were conducted. The total number of tests was 518.

Four measures of performance were considered in this study. These measures of performance were: (1) the average percent a balance is above the optimum solution, in terms of number of stations; (2) time to obtain a balance; (3) the best solution in terms of the lowest number of stations and lowest standard deviation of the slack times, and (4) the largest value of minimum station slack time. Overall it was found that the Modified Hoffmann procedure with a delay factor of 1.5 performed best. The time to obtain a balance using the Modified Hoffmann procedure is significantly less than the time for a solution without the modifications.     

(Z)6, (E)8-Heneicosadien-11-One: Synergistic Sex Pheromone Component of Douglas-Fir Tussock Moth, Orgyia pseudotsugata (McDunnough) (Lepidoptera: Lymantriidae)

Three candidate sex pheromone components, (Z)6,(Z)9-, (Z)6,(E)8-, and (Z)6,(E)9-heneicosadien-11-one (Z6Z9, Z6E8, and Z6E9) were identified in pheromone gland extracts of female Douglas-fir tussock moths (DFTM), Orgyia pseudotsugata (McDunnough). Their occurrence in subnanogram quantities in extracts and structural conversion during analytical procedures and bioassays complicated chemical identifications. Complete identification required comparative analyses of stereoselectively synthesized and female-produced dienones by coupled gas chromatographic–electroantennographic detection (GC-EAD), high-performance liquid chromatography (HPLC) and coupled GC–mass spectrometry (MS). Determination of the pheromone component was contingent upon an experimental design that minimized structural rearrangement of dienones before and during the field test. In a 40-min field experiment, acetonitrile solutions of each of the above dienones were carried on Dry Ice to traps and were syringed onto cotton release devices below trap lids. In combination with the previously known sex pheromone component of DFTM, (Z)6-heneicosen-11-one (Z6), Z6E8 was the only synergistic dienone and the mixture was highly attractive. Because Z6 by itself attracts seven species of tussock moths (two sympatric with DFTM), a blend of Z6 and Z6E8 may impart specificity to DFTM pheromone communication. In commercial lures, this binary blend may facilitate species-specific, sensitive monitoring and efficacious control by mating disruption of this important forest defoliator.     

Structure and Shear Response in Nanometer-Thick Films

Simulations of the structure and dynamics of fluid films confined to a thickness of a few molecular diameters are described. Confining walls introduce layering and in-plane order in the adjacent fluid. The latter is essential to transfer of shear stress. As the film thickness is decreased, by increasing pressure or decreasing the number of molecular layers, the entire film may undergo a phase transition. Spherical molecules tend to crystallize, while short-chain molecules enter a glassy state with strong local orientational and translational order. These phase transitions lead to dramatic changes in the response of the film to imposed shear velocities v. Spherical molecules show an abrupt transition from Newtonian response to a yield stress as they crystallize. Chain molecules exhibit a continuously growing regime of non-Newtonian behavior where the shear viscosity drops as v^−2/3 at constant normal load. The same power law is found for a wide range of parameters, and extends to lower and lower velocities as a glass transition is approached. Once in the glassy state, chain molecules exhibit a finite yield stress. Shear may occur either within the film or at the film/wall interface. Interfacial shear dominates when films become glassy and when the film viscosity is increased by increasing the chain length.