An experimental study of bubble departure diameter in subcooled flow boiling including the effects of orientation angle, subcooling, mass flux, heat flux, and pressure

The effects of orientation angle, subcooling, heat flux, mass flux, and pressure on bubble departure diameter in the isolated bubble regime of subcooled flow boiling were studied by high-speed video in a two-phase flow loop that can accommodate a wide range of flow conditions. Specifically, the following ranges were explored: orientation angles of 0° (downward-facing horizontal), 30°, 45°, 60°, 90° (vertical), and 180° (upward-facing horizontal); mass flux values of 250, 300, 350, and 400 kg/m2 s, corresponding to Froude numbers between 0.42 and 1.06; pressures of 101 (atmospheric), 202, and 505 kPa; two values of the subcooling degrees (10 and 20 °C); and two heat fluxes (0.05 and 0.10 MW/m2). The combination of the test section design, high-speed video camera and LED lighting results in high accuracy (order of 20 μm) in the determination of the bubble departure diameter. The data indicate that the bubble departure diameter increases with increasing heat flux, decreasing mass flux, decreasing subcooling, and decreasing pressure. Also, the bubble departure diameter increases with decreasing orientation angle, i.e. the largest bubbles are found to detach from a downward-facing horizontal surface. The mechanistic bubble departure diameter model of Klausner et al. and its recent modification by Yun et al. were found to correctly predict all the observed parametric trends, but with large average errors and standard deviation: 65.5 ± 75.8% for Klausner's and 37.9 ± 51.2% for Yun's. Since the cube of the bubble departure diameter is used in subcooled flow boiling heat transfer models, such large errors are clearly unacceptable, and underscore the need for more accurate bubble departure diameter models.Douglas C. Spreng FundNuclear Energy Institut

The effects of orientation angle, subcooling, heat flux, mass flux, and pressure on bubble growth and detachment in subcooled flow boiling

Thesis (S.M. and S.B.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 119-122).The effects of orientation angle, subcooling, heat flux, mass flux, and pressure on bubble growth and detachment in subcooled flow boiling were studied using a high-speed video camera in conjunction with a two-phase flow loop that can accommodate a wide range of flow conditions. Specifically, orientation angles of 0' (downward-facing horizontal), 30°, 45°, 60°, and 90° (vertical); mass flux values of 250, 300, 350, and 400 kg/m²s, with corresponding Froude numbers in the range of 0.42 to 1.06; pressures of 101 (atmospheric), 202, and 505 kPa; two values of subcooling (10°C to 20°C); and two heat fluxes (0.05 to 0.10 MW/m²) were explored. The combination of the test section design, high-speed video camera, and LED lighting results in high accuracy (order of 20 microns) in the determination of bubble departure diameter. The data indicate that bubble departure diameter increases with increasing heat flux, decreasing mass flux, decreasing levels of subcooling, and decreasing pressure. Also, bubble departure diameter increases with decreasing orientation angle, i.e. the largest bubbles are found to detach from a downward-facing horizontal surface. The mechanistic bubble departure model of Klausner et al. and its recent modification by Yun et al. were found to correctly predict all the observed parametric trends, but with large average errors and standard deviation: 35.7+/-24.3% for Klausner's and 16.6±11.6% for Yun's. Since the cube of the bubble departure diameter is used in subcooled flow boiling heat transfer models, such large errors are clearly unacceptable, and underscore the need for more accurate bubble departure diameter models to be used in CFD.by Rosemary M. Sugrue.S.M.and S.B

Outcomes of exclusive enteral nutrition in paediatric Crohn\u27s disease

Background/objectives: Exclusive enteral nutrition (EEN) is a safe and effective treatment modality for inducing remission in paediatric Crohn\u27s disease (CD). The primary aim of this study was to compare the outcomes of EEN to corticosteroid (CS) therapy in newly diagnosed, treatment-naïve patients with CD. A secondary aim was to describe the outcomes of EEN in a national cohort of paediatric CD patients over a 10-year period. Subjects/methods: A retrospective chart review was conducted at the Irish national referral centre for paediatric CD. A case-matched analysis was conducted on two cohorts matched for age, gender, disease location, disease behaviour and disease activity, who received CS or EEN as their initial treatment. Subsequently, cohort analysis was conducted on all patients who undertook a course of EEN therapy between 2004 and 2013. Results: The case-matched analysis found higher remission rates after treatment with EEN (24/28, 86%) compared with those with CS (15/28, 54%; P=0.02). Dietetic contacts were found to be pivotal to the success of treatment and the attainment of remission. In total, 59 patients completed EEN at some time-point in their disease course and were included in the cohort analysis. Sixty-nine per cent of this cohort entered clinical remission (41/59). EEN was found to be most effective when used as an initial treatment (P=0.004) and less effective in patients aged under 10 years (P=0.04). Conclusions: EEN should be strongly considered as a favourable primary treatment over CS, especially in those diagnosed over the age of 10 years

Immunocytochemical localization of the neuron-specific form of the c-src gene product, pp60c-src(+), in rat brain

Neurons express high levels of a variant form of the c-src gene product, denoted pp60c-src(+), which contains a 6 amino acid insert in the amino-terminal half of the c-src protein. We have determined the localization of pp60c-src(+) in neurons using an affinity-purified anti-peptide antibody, referred to as affi-SB12, that exclusively recognizes this neuron-specific form of the c-src gene product. Using affi-SB12, we examined the distribution of pp60c-src(+) by immunoperoxidase staining of sections through adult rat brains, pp60c-src(+) was widely distributed in rat brain and appeared to be differentially expressed in subpopulations of neurons. The majority of immunoreactive neurons was found in the mesencephalon, cerebellum, pons, and medulla. Telencephalic structures that contained substantial populations of pp60c-src(+)-immunoreactive neurons included layer V of the cerebral cortex and the ventral pallidum. Within individual neurons, pp60c-src(+) immunoreactivity was localized to the cell soma and dendritic processes, while labeling of axons and nerve terminals (puncta) was not as readily detected. Dense accumulations of immunoreactive axons were rare, being most prominent in portions of the inferior and superior olive, and in the spinal trigeminal nucleus. While the regional distribution of pp60c-src(+) immunoreactivity does not correlate with any specific neuronal cell type or first messenger system, this unique pattern of expression of pp60c-src(+) suggests the existence of a previously uncharacterized functional organization within the brain. Furthermore, the localization of this neuron-specific tyrosine kinase in functionally important areas of the nerve cell, namely, dendritic processes, axons, and nerve terminals, suggests that pp60c-src(+) may regulate pleiotropic functions in specific classes of neurons in the adult central nervous system

CV19015

This report provides the main results and findings of the fourteenth annual underwater television survey on the ‘Smalls grounds’ ICES assessment area; Functional Unit 22. The survey was multi-disciplinary in nature collecting UWTV, CTD and other ecosystem data. A total of 41 UWTV stations were surveyed successfully (high quality image data), carried out over an isometric grid at 4.5nmi or 8.3km intervals. The precision, with a CV of 9%, was well below the upper limit of 20% recommended by SGNEPS (ICES, 2012). The 2019 abundance estimate was 30% higher than in 2018 and at 1121 million is below the MSY Btrigger reference point (990 million). Using the 2019 estimate of abundance and updated stock data implies catch in 2020 that correspond to the F ranges in the EU multi annual plan for Western Waters are between 2247 and 2820 tonnes (assuming that discard rates and fishery selection patterns do not change from the average of 2016–2018). One species of sea pens were recorded as present at the stations surveyed: Virgularia mirabilis. Trawl marks were observed at 57% of the stations surveyed

Comparison and Uncertainty Quantification of Two-Fluid Models forBubbly Flows with NEPTUNE_CFD and STAR-CCM+

International audienceThe nuclear industry is interested in better understanding the behavior of turbulent boiling flowsand in using modern computational tools for the design and analysis of advanced fuels and reactorsand for simulation and study of mitigation strategies in accident scenarios. Such interests serve asdrivers for the advancement of the 3-dimensional multiphase Computational Fluid Dynamicsapproach. A pair of parallel efforts have been underway in Europe and in the United States, theNEPTUNE and CASL programs respectively, that aim at delivering advanced simulation tools thatwill enable improved safety and economy of operations of the reactor fleet. Results from acollaboration between these two efforts, aimed at advancing the understanding of multiphaseclosures for pressurized water reactor (PWR) application, are presented. Particular attention is paidto the assessment and analysis of the different physical models implemented in NEPTUNE_CFDand STAR-CCM+ codes used in the NEPTUNE and the CASL programs respectively, forapplication to turbulent two-phase bubbly flows. The experiments conducted by Liu and Bankoff(Liu, 1989; Liu and Bankoff 1993a and b) are selected for benchmarking, and predictions from thetwo codes are presented for a broad range of flow conditions and with void fractions varyingbetween 0 and 50percent. Comparison of the CFD simulations and experimental measurements revealsthat a similar level of accuracy is achieved in the two codes. The differences in both sets of closuremodels are analyzed, and their capability to capture the main features of the flow over a wide rangeof experimental conditions are discussed. This analysis paves the way for future improvements ofexisting two-fluid models. The benchmarks are further leveraged for a systematic study of thepropagation of model uncertainties. This provides insights into mechanisms that lead to complexinteractions between individual closures (of the different phenomena) in the multiphase CFDapproach. As such, it is seen that the multi-CFD-code approach and the principled uncertaintyquantification approach are both of great value in assessing the limitations and the level of maturityof multiphase hydrodynamic closures

The Role of Monitoring Interpretive Rates, Concordance Between Cytotechnologist and Pathologist Interpretations Before Sign-Out, and Turnaround Time in Gynecologic Cytology Quality Assurance Findings From the College of American Pathologists Gynecologic Cytopathology Quality Consensus Conference Working Group 1

Context.-The College of American Pathologists (CAP) conducted a national survey of gynecologic cytology quality assurance (QA) practices. Experts in gynecologic cytology were asked to join 5 working groups that studied the survey data on different aspects of QA. Evaluating the survey data and follow-up questions online, together with a review of pertinent literature, the working groups developed a series of preliminary statements on good laboratory practices in cytology QA. These were presented at a consensus conference and electronic voting occurred. Objective.-To evaluate a set of QA monitors in gynecologic cytology. Working group 1 evaluated (1) monitoring interpretive rate categories for Papanicolaou tests (Pap tests), (2) concordance of cytotechnologist and pathologist interpretations before sign-out, and (3) turnaround time for Pap tests. Data Sources.-The statements are based on a survey of gynecologic cytology QA practice patterns and of opinions from working group members and consensus conference attendees. Conclusions.-The outcomes of this process demonstrate the current state of practice patterns in gynecologic cytology QA. Monitoring interpretive rates for all Bethesda System categories is potentially useful, and it is most useful to monitor interpretive rates for cytotechnologists individually and in comparison to the entire laboratory. Laboratories need to determine what level of discrepancy between cytotechnologist and pathologist interpretations of Pap tests is important to track. Laboratories should consider formalizing procedures and policies to adjudicate such discrepant interpretations. Turnaround time should be monitored in gynecologic cytology, but individual laboratories should determine how to measure and use turnaround time internally

Kinetics of Proton Transport into Influenza Virions by the Viral M2 Channel

M2 protein of influenza A viruses is a tetrameric transmembrane proton channel, which has essential functions both early and late in the virus infectious cycle. Previous studies of proton transport by M2 have been limited to measurements outside the context of the virus particle. We have developed an in vitro fluorescence-based assay to monitor internal acidification of individual virions triggered to undergo membrane fusion. We show that rimantadine, an inhibitor of M2 proton conductance, blocks the acidification-dependent dissipation of fluorescence from a pH-sensitive virus-content probe. Fusion-pore formation usually follows internal acidification but does not require it. The rate of internal virion acidification increases with external proton concentration and saturates with a pKm of ∼4.7. The rate of proton transport through a single, fully protonated M2 channel is approximately 100 to 400 protons per second. The saturating proton-concentration dependence and the low rate of internal virion acidification derived from authentic virions support a transporter model for the mechanism of proton transfer

The “Smalls” Nephrops Grounds (FU22) 2022 UWTV Survey Report and catch scenarios for 2023

This report provides the main results and findings of the seventeenth annual underwater television survey on the ‘Smalls grounds’ ICES assessment area; Functional Unit 22. The survey was multi-disciplinary in nature collecting UWTV and other ecosystem data. A total of 42 UWTV stations were surveyed successfully (high quality image data), carried out over an isometric grid at 4.5nmi or 8.3km intervals. The precision, with a CV of 7%, was well below the upper limit of 20% recommended by SGNEPS (ICES, 2012). The 2022 abundance estimate was 36% higher than in 2022 and at 895 million is below the MSY Btrigger reference point (990 million). Using the 2022 estimate of abundance and updated stock data implies catch in 2023 that correspond to the ICES MSY approach of 2548 tonnes, assuming that discard rates and fishery selection patterns do not change from the average of 2019 - 2021. One species of sea pen was recorded as present at the stations surveyed: Virgularia mirabilis. Trawl marks were observed at 29% of the stations surveyed