Computational analysis of two-phase flow in horizontal bundles

Phase distribution during boiling flow in horizontal channels and fuel bundles tends to be asymmetric, particularly at low flows, due to gravity induced separation of the phases. Standard models and computational techniques developed for flow on vertical rod bundles cannot adequately simulate this tendency in horizontal flows, so more advanced techniques involving thermal and mechanical disequilibrium between phases are required.The paper describes the development and application of a drift flux code ASSERT (Advanced Solution of Subchannel Equations in Reactor Thermalhydraulics) which models departure from mechanical and thermal equilibrium between phases. Details of the model and computational technique are given, and parametric studies are shown to illustrate the capability of the code to simulate two-phase flow in horizontal bundles.Fundamental to the successful application of such a code are phenomenological studies aimed at the quantification of the empirical relationships selected for use. The paper concludes with a detailed study of mechanisms governing two-phase flow between neighbouring horizontal channels, isolating the driving effects of pressure gradient, gravity head and turbulent interchange by means of comparison with available experimental data.     

Comparing the reading-storage test to the paraphrase test as measures of the primary effect of prose reading.

Compared reading-storage tests to paraphrase tests to determine the sensitivity of each to the gain in comprehension that results from reading prose. In Exp I, 48 college students were presented tests on 8 passages at 4 levels of difficulty under reading and nonreading conditions. In Exp II, 40 college students were presented tests on 5 passages with the amount of information in the passages systematically manipulated using a word deletion scheme. The reading-storage tests were, on the average, less sensitive to gain than the paraphrase tests, but gain on the paraphrase tests was more variable. The reading-storage test is a completely objective technique which appears to be about as sensitive to comprehension gain as is the subjectively developed paraphrase type of test. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimism, coping, and health: Assessment and implications of generalized outcome expectancies.

Describes a scale measuring dispositional optimism, defined in terms of generalized outcome expectancies. Two preliminary studies, involving a total of 438 male and 336 female undergraduates, assessed the scale's psychometric properties and its relationships with several other instruments. The scale was then used in a longitudinal study of symptom reporting among 79 male and 62 female undergraduates. Ss were asked to complete 3 questionnaires 4 wks before the end of a semester. Included in the questionnaire battery were the measure of optimism, a measure of private self-consciousness, and a 39-item physical symptom checklist. Ss completed the same set of questionnaires again on the last day of class. Consistent with predictions, Ss who initially reported being highly optimistic were subsequently less likely to report being bothered by symptoms (even after correcting for initial symptom-report levels) than were Ss who initially reported being less optimistic. This effect tended to be stronger among Ss high in private self-consciousness than among those lower in private self-consciousness. Discussion centers on other health related applications of the optimism scale and the relationships between the theoretical orientation of the scale and several related theories. (3 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Self-focusing effects of heartbeat feedback.

Two studies tested the hypothesis that auditory heartbeat feedback leads to an increase in self-directed attention. In Exp I, 10 female undergraduates exposed to a sound representing their heartbeat made greater self-attributions for hypothetical outcomes than did 10 similar Ss exposed to the same sound identified as an extraneous noise. Furthermore, Ss in the heartbeat condition showed a pattern of color-naming latencies (on a color-word test) that was consistent with the hypothesis that self-related information was being activated in memory. In contrast, no such pattern was observed among Ss in the noise condition. In Exp II, with 51 female and 28 male undergraduates, comparisons with appropriate control groups indicated that neither an extraneous noise nor the attachment of a heartbeat-recording device influenced self-attribution, but that the presence of either a constant or an accelerating heartbeat increased self-attribution. The latter 2 conditions did not differ from each other. Methodological and theoretical implications are discussed. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Self-focusing effects of dispositional self-consciousness, mirror presence, and audience presence.

Notes that self-awareness theory has generated a considerable amount of research activity; however, the most widely used manipulation of self-focus—the mirror—has not been satisfactorily validated. Exp I was an attempt to do so. At the same time an attempt was made to validate the Self-Consciousness Scale (SCS), an instrument designed to measure chronic dispositions to be self-attentive. 79 female undergraduates responded to a sentence completion blank either in an empty room or while facing a mirror. Results indicate that the mirror does manipulate, and the private subscale of the SCS does measure, self-attention. Exp II, with 81 female undergraduates, was a replication of the 1st study, but using an audience instead of a mirror. Results indicate that audience presence also heightens self-attention. Implications for attentional analyses of social behavior are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distinguishing optimism from neuroticism (and trait anxiety, self-mastery, and self-esteem): A reevaluation of the Life Orientation Test.

Research on dispositional optimism as assessed by the Life Orientation Test (M. F. Scheier and C. S. Carver, 1985) has been challenged on the grounds that effects attributed to optimism are indistinguishable from those of unmeasured third variables, most notably, neuroticism. Data from 4,309 Ss show that associations between optimism and both depression and aspects of coping remain significant even when the effects of neuroticism, as well as the effects of trait anxiety, self-mastery, and self-esteem, are statistically controlled. Thus, the Life Orientation Test does appear to possess adequate predictive and discriminant validity. Examination of the scale on somewhat different grounds, however, does suggest that future applications can benefit from its revision. Thus, we also describe a minor modification to the Life Orientation Test, along with data bearing on the revised scale's psychometric properties. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Can observational techniques help novices overcome the software inspection learning curve? An empirical investigation

When learning a new software engineering technique, there is a learning curve that must be overcome. In particular, when studies are conducted in a classroom setting, researchers need a method for quickly accelerating the experience of novice subjects to allow the results to be more applicable in industrial settings. In this paper, we propose and test a method to enable novices to gain process experience to allow them to more quickly overcome the learning curve. The method we evaluate allows an inspector to gain experience with the inspection process by observing an inspection performed by someone else. The results of the study show that the proposed method for gaining experience appears to be useful in some limited cases, that is, for low experienced subjects who were inspecting a requirements document from a domain in which they had low knowledge. Based on the results of this study, we are able to propose some new related hypotheses to be tested in future studies.     

A spectral meteorological model on the ICL DAP

The key points to the implementation of a meteorological spectral model on the ICL Distributed Array Processor (DAP) are presented. Spectral models involve transforming the variables between spectral and gridpoint space and these spectral transforms comprise of Legendre and fast Fourier transforms.

The storage format of the data is discussed and the algorithms used for the Legendre transforms presented. Timings of these algorithms are compared with those from a serial machine.     

A Complementary Pair of Four-Terminal Silicon Synapses

We have developed a complementary pair of pFETand nFET floating-gate silicon MOS transistors foranalog learning applications. The memory storage is nonvolatile;hot-electron injection and electron tunneling permit bidirectionalmemory updates. Because these updates depend on both the storedmemory value and the transistor terminal voltages, the synapsescan implement a learning function. We have derived a memory-updaterule for both devices, and have shown that the synapse learningfollows a simple power law. Unlike conventional EEPROMs, thesynapses allow simultaneous memory reading and writing. Synapsetransistor arrays can therefore compute both the array output,and local memory updates, in parallel. We have fabricated prototypesynaptic arrays; because the tunneling and injection processesare exponential in the transistor terminal voltages, the writeand erase isolation between array synapses is better than 0.01 percentThe synapses are small, and typically are operated at subthresholdcurrent levels; they will permit the development of dense, low-powersilicon learning systems.