A generation control system for Hoover Powerplant to optimize plantoperating efficiency

A digital control system which provides unit commitment functions and real-time generation control while optimizing plant operating efficiency was put in service at the Hoover hydroelectric powerplant (USA) on June 1, 1987. The theory of the unit commitment and generation allocation schemes is presented. Results showing the operating efficiency gains during the first year of system operation are given     

An individual and quantitative measure of stereotypes.

Proposes a quantitative and individual measure of stereotyping, based on defining stereotypes as probabilistic predictions that distinguish the stereotyped group from others. Data indicate that the proposed measure, though related to the familiar Katz and Braly (D. Katz and K. W. Braly, 1933) checklist, is a substantially new measure of stereotyping rather than simply a quantitative version of the checklist. It is argued that the theoretical and empirical value of the proposed measure is justification for abandoning the Katz and Braly measure. Theoretically, the new measure relates stereotype research to attribution theory as part of a Bayesian approach to the psychology of prediction. Empirically, the new measure opens interesting questions about stereotypes, especially about stereotype validity and the "kernel of truth" hypothesis. A study using the new measure revealed that diverse groups of Ss (N?=?75) had some similar stereotypes of Black Americans, that these stereotypes were relatively accurate, and that contrary to the "kernel of truth" hypothesis, these stereotypes were seldom exaggerated. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modification of the pigeon's visual startle reaction by the sensory environment.

Seven experiments related amplitude and latency of 20 racing pigeons' startle response, elicited by an intense visual stimulus, to antecedent auditory and visual events in the sensory environment. Data indicate that (a) within broad limits the amplitude of the reflex was a positive function of the intensity of the sensory background prevailing at the time of startle elicitation; (b) a change in the sensory environment occurring 15-2,000 msec prior to the startle-eliciting stimulus inhibited the amplitude of the response; and (c) a change in the sensory environment less than 10 msec prior to the startle-eliciting stimulus reduced the latency of the response. Findings are consistent with previous research on acoustic elicited startle in the rat. The overall configuration of the results suggests that a pathway including the reticulospinal tract and the bulbopontine reticular nuclei could be the major mediator of startle. In these terms, latency-reduction effects would occur because of partial activation of this pathway, amplitude inhibition would occur because of cerebellar influence, and amplitude facilitation would reflect cerebral or striatal influences. (49 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developing mechanistic understanding of granular behaviour in complex moving geometry using the Discrete Element Method: Part B: Investigation of flow and mixing in the Turbula® mixer

As a consequence of increasing computer power and more readily useable commercial codes, the Discrete Element Method is being used in an increasing range of applications to simulate increasingly complex processes, often for evaluation of machinery prototypes. This presents the additional challenge of analysis of results, in particular to extract flow and mixing mechanisms with a view to improving design or operation.The Turbula mixer is a laboratory scale mixer, which is widely used in industry for the development or testing of new granular products. It comprises a simple vessel geometry (cylinder) that moves with a complex, yet regular, 3D motion giving rise to rapid and thorough mixing of the contents. The mixer presents an ideal system for evaluation of the power of DEM to simulate complex processes and to develop protocols for processing the results of the simulation. Initial results of this investigation, presented in this paper, show that mixing behaviour changes non-monotonically as a function of mixer speed. For the system of monodisperse glass spheres it is shown that mixing rate (in terms of number of mixer revolutions to achieve complete mixing) initially decreases with increasing speed and subsequently increases. The behaviour is suggestive of a transition in the flow process and is the subject of further investigation.     

Why do I like thee: Is it your performance or my orders?

Examined the extent to which employee evaluations are determined by the leader's influence tactics and the assessments of followers' motives rather than by their performance. 113 business majors were randomly assigned to act as authoritarian or democratic leaders of 5-person work groups that manufactured model airplanes. Measures of leader influence tactics, leader assessments of the extent to which followers were either internally or externally motivated to work effectively, and leader evaluations of followers were gathered at the end of the work session. The number of airplane models produced was used as the performance measure. It was found that (a) the democratic leaders perceived the followers as internally motivated to work effectively, (b) the leaders' perception of the followers as internally motivated was strongly related to favorable evaluations of the followers, and (c) the leaders' employee evaluations were not related to the followers' performance. Findings are discussed in terms of previous research that has linked the use of power to evaluations of followers. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Code of practice for brachytherapy physics: report of the AAPM Radiation Therapy Committee Task Group No. 56. American Association of Physicists in Medicine

Recommendations of the American Association of Physicists in Medicine (AAPM) for the practice of brachytherapy physics are presented. These guidelines were prepared by a task group of the AAPM Radiation Therapy Committee and have been reviewed and approved by the AAPM Science Council.     

Using X‐Ray Microtomography for Characterisation of Catalyst Particle Pore Structure

The use of a high‐energy synchrotron radiation source has permitted the introduction of high‐resolution X‐ray microtomography imaging as a method of non‐intrusive and non‐destructive three‐dimensional (3D)visualized characterization of porous media. The use of a combination of X‐ray microtomography, along with mercury porosimetry and Low Melting Point Alloy (LMPA) intrusion potentially provides a more complete approach to more accurate catalyst pore structure characterisation and modelling. This combined approach has been applied to the study of an industrial alumina catalysts support. The data collected from the study has been used to develop and generate an improved pore network model basis, in which both heterogeneity and hierarchy are considered in obtaining an improved pore architecture and pore size distribution.