Investigation of hydrogen-burn damage in the Three Mile Island Unit 2 reactor building

About 10 hours after the March 28, 1979 Loss-of-Coolant Accident began at Three Mile Island Unit 2, a hydrogen deflagration of undetermined extent occurred inside the reactor building. Examinations of photographic evidence, available from the first fifteen entries into the reactor building, yielded preliminary data on the possible extent and range of hydrogen burn damage. These data, although sparse, contributed to development of a possible damage path and to an estimate of the extent of damage to susceptible reactor building items. Further information gathered from analysis of additional photographs and samples can provide the means for estimating hydrogen source and production rate data crucial to developing a complete understanding of the TMI-2 hydrogen deflagration. 34 figures

Experimental and theoretical study of flame inhibition by bromine-containing compounds

The present paper represents the first effort to date in which a combined experimental and theoretical approach has been used to study the effects of several inhibitors on hydrocarbon-air flames. This work is part of an attempt to build a consistent picture of chemical kinetic flame inhibition, beginning with a simple halogen molecule such as HBr and progressing sequentially towards more complex and more practical inhibitors such as CF/sub 3/Br. Inhibition efficiency can be defined as the rate of flame speed reduction, the amount of flame speed change per unit inhibitor added. Both the numerical model and the flame tube measurements found that the inhibition efficiency gradually decreases as the amount of inhibitor is increased. The present experimental and modeling results are shown, together with earlier data for CF/sub 3/Br-CH/sub 4/-air and CF/sub 3/Br-C/sub 3/H/sub 8/-air as well as HBr-CH/sub 4/-air, CH/sub 3/Br-CH/sub 4/-air and CF/sub 3/Br-CH/sub 4/-air. In the numerical study it was found that a stoichiometric methane-air mixture with up to 8% methyl bromide could support a flame, propagating at a speed of about 5 cm/sec, even though the addition of the first 1% of CH/sub 3/Br had reduced the flame speed from 38 cm/sec to about 26 cm/sec. Extensions of the model to include CF/sub 3/Br are currently under development. The available experimental data suggest that CF/sub 3/Br is somewhat more efficient as an inhibitor than HBr or CH/sub 3/Br

Fire protection research for energy technology projects; FY 79 year-end report

This report describes work performed in fiscal year 1979, on a DOE funded study entitled Fire Protection Research for Energy Technology Projects. The primary goal of this program is to ensure that fire protection measures for Fusion Energy Experiments (FEE) evolve concurrently with the complexity of FEE. Ultimately, it is planned that the detailed study of fusion experiments will provide an analytical methodology which can be applied to the full range of energy technology projects. We attempt to achieve this objective by coordinately advancing 3 (three) major task areas; (a) determine the fire hazards of current FEE facilities (b) assess the ability of accepted fire management strategies to meet and negate the hazard, (c) perform unique research into problem areas we have identified to provide input into analytical fire growth and damage assessment models

Fire-protection research for DOE facilities: FY 82 year-end report

We summarize our research in FY 82 for the DOE-sponsored project, Fire Protection Research for DOE Facilities. This research program was initiated in 1977 to advance fire-protection strategies for energy technology facilities to keep abreast of the unique fire problems that develop along with energy technology research. Since 1977, the program has broadened its original scope, as reflected in previous year-end reports. We are developing an analytical methodology through detailed study of fusion energy experiments at Lawrence Livermore National Laboratory (LLNL). Using these experiments as models for methodology development, we are concurrently advancing three major task areas: (1) the identification of fire hazards unique to current fusion energy facilities; (2) the evaluation of accepted fire-management measures to meet and negate hazards; and (3) the performance of unique research into problem areas we have identified to provide input into analytical fire-growth and damage-assessment models

Fire-Protection Research for Energy-Technology Projects: FY 1981 year-end report

This report summarizes research conducted in fiscal year 1981 for the DOE-supported project, Fire Protection Research for Energy Technology Projects. Initiated in 1977, this ongoing research program was conceived to advance fire protection strategies for Energy Technology Projects to keep abreast of the unique fire problems that are developing with the complexity of energy technology research. We are developing an analytical methodology through detailed study of fusion energy experiments at Lawrence Livermore National Laboratory (LLNL). Employing these facilities as models for methodology development, we are simultaneously advancing three major task areas: (1) determination of unique fire hazards of current fusion energy facilities; (2) evaluation of the ability of accepted fire management measures to meet and negate hazards; and (3) performance of unique research into problem areas we have identified to provide input into analytical fire-growth and damage-assessment models

Fire protection research for DOE facilities: FY 83 year-end report

We summarize our research in FY 83 for the DOE-sponsored project, Fire Protection Research for DOE Facilities. This research program was initiated in 1977 to advance fire-protection strategies of energy technology facilities in order to keep abreast of the unique fire problems that develop along with energy technology research. Since 1977, the program has broadened its original scope, as reflected in previous year-end reports. We are developing an analytical methodology through detailed study of fusion energy experiments at Lawrence Livermore National Laboratory (LLNL). Using these experiments as models for methodology development, we are currently advancing three major task areas: (1) the identification of fire hazards unique to fusion energy facilities, (2) the evaluation of accepted fire-management measures to meet the negate hazards, and (3) the performance of unique research into problem areas we have identified to provide input into analytical fire-growth and damage-assessment models

Predicting Age from White Matter Diffusivity with Residual Learning

Imaging findings inconsistent with those expected at specific chronological age ranges may serve as early indicators of neurological disorders and increased mortality risk. Estimation of chronological age, and deviations from expected results, from structural MRI data has become an important task for developing biomarkers that are sensitive to such deviations. Complementary to structural analysis, diffusion tensor imaging (DTI) has proven effective in identifying age-related microstructural changes within the brain white matter, thereby presenting itself as a promising additional modality for brain age prediction. Although early studies have sought to harness DTI's advantages for age estimation, there is no evidence that the success of this prediction is owed to the unique microstructural and diffusivity features that DTI provides, rather than the macrostructural features that are also available in DTI data. Therefore, we seek to develop white-matter-specific age estimation to capture deviations from normal white matter aging. Specifically, we deliberately disregard the macrostructural information when predicting age from DTI scalar images, using two distinct methods. The first method relies on extracting only microstructural features from regions of interest. The second applies 3D residual neural networks (ResNets) to learn features directly from the images, which are non-linearly registered and warped to a template to minimize macrostructural variations. When tested on unseen data, the first method yields mean absolute error (MAE) of 6.11 years for cognitively normal participants and MAE of 6.62 years for cognitively impaired participants, while the second method achieves MAE of 4.69 years for cognitively normal participants and MAE of 4.96 years for cognitively impaired participants. We find that the ResNet model captures subtler, non-macrostructural features for brain age prediction.Comment: SPIE Medical Imaging: Image Processing. San Diego, CA. February 2024 (accepted as poster presentation

Mid-portion Achilles tendinopathy: why painful? An evidence-based philosophy

Chronic mid-portion Achilles tendinopathy is generally difficult to treat as the background to the pain mechanisms has not yet been clarified. A wide range of conservative and surgical treatment options are available. Most address intratendinous degenerative changes when present, as it is believed that these changes are responsible for the symptoms. Since up to 34% of asymptomatic tendons show histopathological changes, we believe that the tendon proper is not the cause of pain in the majority of patients. Chronic painful tendons show the ingrowth of sensory and sympathetic nerves from the paratenon with release of nociceptive substances. Denervating the Achilles tendon by release of the paratenon is sufficient to cause pain relief in the majority of patients. This type of treatment has the additional advantage that it is associated with a shorter recovery time when compared with treatment options that address the tendon itself. An evidence-based philosophy on the cause of pain in chronic mid-portion Achilles tendinopathy is presented

On the Functional Significance of the P1 and N1 Effects to Illusory Figures in the Notch Mode of Presentation

The processing of Kanizsa figures have classically been studied by flashing the full “pacmen” inducers at stimulus onset. A recent study, however, has shown that it is advantageous to present illusory figures in the “notch” mode of presentation, that is by leaving the round inducers on screen at all times and by removing the inward-oriented notches delineating the illusory figure at stimulus onset. Indeed, using the notch mode of presentation, novel P1and N1 effects have been found when comparing visual potentials (VEPs) evoked by an illusory figure and the VEPs to a control figure whose onset corresponds to the removal of outward-oriented notches, which prevents their integration into one delineated form. In Experiment 1, we replicated these findings, the illusory figure was found to evoke a larger P1 and a smaller N1 than its control. In Experiment 2, real grey squares were placed over the notches so that one condition, that with inward-oriented notches, shows a large central grey square and the other condition, that with outward-oriented notches, shows four unconnected smaller grey squares. In response to these “real” figures, no P1 effect was found but a N1 effect comparable to the one obtained with illusory figures was observed. Taken together, these results suggest that the P1 effect observed with illusory figures is likely specific to the processing of the illusory features of the figures. Conversely, the fact that the N1 effect was also obtained with real figures indicates that this effect may be due to more global processes related to depth segmentation or surface/object perception

The Effect of Inappropriate Calibration: Three Case Studies in Molecular Ecology

Time-scales estimated from sequence data play an important role in molecular ecology. They can be used to draw correlations between evolutionary and palaeoclimatic events, to measure the tempo of speciation, and to study the demographic history of an endangered species. In all of these studies, it is paramount to have accurate estimates of time-scales and substitution rates. Molecular ecological studies typically focus on intraspecific data that have evolved on genealogical scales, but often these studies inappropriately employ deep fossil calibrations or canonical substitution rates (e.g., 1% per million years for birds and mammals) for calibrating estimates of divergence times. These approaches can yield misleading estimates of molecular time-scales, with significant impacts on subsequent evolutionary and ecological inferences. We illustrate this calibration problem using three case studies: avian speciation in the late Pleistocene, the demographic history of bowhead whales, and the Pleistocene biogeography of brown bears. For each data set, we compare the date estimates that are obtained using internal and external calibration points. In all three cases, the conclusions are significantly altered by the application of revised, internally-calibrated substitution rates. Collectively, the results emphasise the importance of judicious selection of calibrations for analyses of recent evolutionary events