Statistical Characterization of Heat Release Rates from Electrical Enclosure Fires for Nuclear Power Plant Applications

Since the publication of NUREG/CR-6850/EPRI 1011989 in 2005, the US nuclear industry has sought to re-evaluate the default peak heat release rates (HRRs) for electrical enclosure fires typically used as fire modeling inputs to support fire probabilistic risk assessments (PRAs), considering them too conservative. HRRs are an integral part of the fire phenomenological modeling phase of a fire PRA, which consists of identifying fire scenarios which can damage equipment or hinder human actions necessary to prevent core damage. Fire ignition frequency, fire growth and propagation, fire detection and suppression, and mitigating equipment and actions to prevent core damage in the event fire damage still occurred are all parts of a fire PRA. The fire growth and propagation phase incorporates fire phenomenological modeling where HRRs have a key effect. A major effort by the Electric Power Research Institute and Science Applications International Corporation in 2012 was not endorsed by the US Nuclear Regulatory Commission (NRC) for use in risk-informed, regulatory applications. Subsequently the NRC, in conjunction with the National Institute of Standards and Technology, conducted a series of tests for representative nuclear power plant electrical enclosure fires designed to definitively establish more realistic peak HRRs for these often important contributors to fire risk. The results from these tests are statistically analyzed to develop two probabilistic distributions for peak HRR per unit mass of fuel that refine the values from NUREG/CR-6850, thereby providing a fairly simple means by which to estimate peak HRRs from electrical enclosure fires for fire modeling in support of fire PRA. Unlike NUREG/CR-6850, where five different distributions are provided, or NUREG-2178, which now provides 31, the peak HRRs for electrical enclosure fires can be characterized by only two distributions. These distributions depend only on the type of cable, namely qualified versus unqualified, for which the mean peak HRR per unit mass is 11.3 and 23.2 kW/kg, respectively, essentially a factor of two difference. Two-sided, 90th percentile confidence bounds are 0.0915 to 41.2 kW/kg for qualified cables, and 0.0272 to 95.9 kW/kg for unqualified cables. From the mean (~70th percentile) upward, the peak HRR/kg for unqualified cables is roughly twice that for qualified, increasing slightly with higher percentile, an expected phenomenological trend. Simulations using variable fuel loadings are performed to demonstrate how the results from this analysis may be used for nuclear power plant applications.     

空气节能器在空调系统中的应用

空气节能器是美国大中型建筑全空气系统和空气-水系统中应用广泛的一种节能设备.ANSI/ASHRAE/IESNA Standard 90.1-2007规定,凡是带风机的冷却系统都应考虑使用空气侧或水侧节能器.介绍了空气节能器的组成、控制方式和4种运行模式,并指出空气节能器运行中容易出现的问题.鉴于我国的气候、大气污染状况及空调系统形式,认为目前空气节能器应用于我国大中型建筑的空调系统中的条件尚不成熟.     

Individual differences in stimulus intensity modulation and its relationship to two styles of depression in older adults.

Research comparing depressive persons with and without manic symptoms shows striking parallels with differences between augmenters and reducers on the Kinesthetic Aftereffect (KAE) task (A. Petrie, 1967). Twenty-three community-dwelling older adults identified by the Minnesota Multiphasic Personality Inventory (S. R. Hathaway & J. C. McKinley, 1951) as depressive without manic symptoms were compared with 24 older adults with manic symptoms on the KAE, the NEO Personality Inventory (NEO-PI; P. T. Costa & R. R. McCrae, 1985), and Strelau (J. Strelau, 1983) Temperament Inventory. As hypothesized, augmentation was related to depression without manic symptoms, and reduction was related to depression with manic symptoms. Stepwise discriminant analyses indicated that the KAE is a potent discriminator between the 2 types of depression. Three characteristics of Strelau's "strength of nervous system"—excitation, and inhibition and mobility—discriminate significantly between the 2 groups as well as NEO extraversion and conscientiousness. Results suggest that older depressive persons with and without manic symptoms may benefit from different therapeutic interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Physical attractiveness and subjective well-being.

Three studies were conducted to determine whether physical attractiveness (PAT) is related to subjective well-being (SWB). In the first study (N?=?221), unselected students were photographed and videotaped. In the second study (N?=?131), participants were selected on the basis of extremes in PAT, and in the third study (N?=?155), participants were preselected for extreme scores on SWB. Correlations between SWB and PAT varied from .03 to .33. In Study 1 the mean correlation between PAT and SWB was .13. When appearance enhancers (hair, clothing, and jewelry) were covered or removed in Studies 2 and 3, the correlation between PAT and SWB dropped, suggesting that part of the SWB–PAT relation might be due to happier people doing more to enhance their beauty. The impact of PAT on SWB may be mitigated by the fact that others agree on a target's PAT at only modest levels. It was found that self-perceptions of PAT were correlated with both one's objective PAT and one's SWB. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spontaneous coronary artery dissection associated with oral contraceptive use

A 39-year-old woman presented with acute myocardial infarction due to spontaneous dissection of the left anterior descending artery. This was treated conservatively. She had been on combined oral contraceptive pills from the age of 22. Repeat coronary angiography 7 months later revealed spontaneous complete healing.     

Evidence for the Participation of Singlet Oxygen in the Vat–dye Photosensitized Degradation of Cellulose

A study has been made of the vat–dye photosensitized degradation of cellulose. Whilst the part played by the dyes in direct hydrogen abstraction from a cellulose substrate cannot be overlooked, it is apparent that the role played by singlet oxygen is important. The ability of a dye to produce singlet oxygen has been studied by measuring the amount of tetraphenylcyclopentadienone the dye can photo–oxidize. It would appear that the singlet oxygen is initially formed in its high energy g state by energy transfer from the triplet state of the dye to ground state molecular oxygen. Luminescence spectroscopy has been employed in order to gain information about the excited state energies of the dye molecules, and an electron spin resonance study of the dyes in rigid media has been carried out in order to obtain information about the triplet state.     

Location errors in tachistoscopic recognition: Guesses, probe errors, or spatial confusions?

Examined whether location errors in tachistoscopic visual probe tasks reflect (1) uncertainty about the actual position of items, (2) inappropriate guesses, encouraged by a requirement to respond, or (3) confusion about the position being tested. 46 undergraduates completed probe tasks in which they provided confidence ratings on each trial and tasks that substituted a color cue for a visual pointer or used a double bar probe. Results suggest that location errors on visual probe tasks reflect confusion about the spatial position of target items. Findings are consistent with data questioning the concept of iconic memory and imply that the bar-probe task cannot be used to study precategorical visual memory. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptions of counselor source characteristics by premature and successful terminators.

Examined 56 premature and 148 successful terminators' perceptions of counselor source characteristics and satisfaction with counseling services at a university counseling center. S-completed measures included the Client Satisfaction Questionnaire and a counselor rating form. Results indicate that Ss who terminated prematurely were less satisfied with counseling services that they received and viewed their counselors as less expert, attractive, and trustworthy than did Ss who terminated successfully. Ss who responded anonymously to the evaluation form viewed the counselors as less attractive and trustworthy and also expressed less satisfaction with counseling than did those who did not respond anonymously. Significant though modest correlations between ratings of source characteristics and client satisfaction were also found. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)