4,774 research outputs found
Mist Explosions using the Hartmann Dust Explosion Equipment
Explosion hazards in the USA and EU include gases, vapors, mists and dusts. There is guidance on the measurement of lean flammability limit and reactivity for gases, vapors and dusts but not for mists explosions. This work explores the use of a modified Hartmann explosion tube for investigating the lean flammability limit and reactivity of mist explosions. Flammable liquids below their flash point can explode if the liquid is atomized and pump diesel fuel was investigated in this work, as the flash point is above 60oC. Each liquid has a critical drop size necessary for it to explode and this is related to the liquid volatility and viscosity. It is about 70µm for kerosene and 10µm for tetralin. For a liquid mist to behave close to a gas in an explosion the drop size has to be small enough to be heated and vaporized in the time it takes the droplet to travel through a laminar flame preheat zone, which is about 1mm at stoichiometric conditions. The use of high pressure air injection in dust explosion test equipment was investigated using the ISO 1m3 dust explosion vessel, but this could not be made to work, nor could the standard Hartman equipment. However, a simply modification to the Hartman equipment enabled repeatable mist explosions to be generated for diesel. The air deflector was removed from the Hartmann equipment and the liquid injected down the air delivery tube. The reactivity of diesel mist was determined from the rate of pressure rise prior to the explosion tube vent bursting and from the measured initial flame speed. The lean flammability limit of diesel mists was determined as 0.15∅ and no rich limit was found, with tests up to an Ø of 5. It was concluded that the Hartmann equipment provides a good method for the characterization of mist explosions for diesel like aerosol
Phosphorylation of eIF4GII and 4E-BP1 in response to nocodazole treatment: a reappraisal of translation initiation during mitosis
Translation mechanisms at different stages of the cell cycle have been studied for many years, resulting in the dogma that translation rates are slowed during mitosis, with cap-independent translation mechanisms favored to give expression of key regulatory proteins. However, such cell culture studies involve synchronization using harsh methods, which may in themselves stress cells and affect protein synthesis rates. One such commonly used chemical is the microtubule de-polymerization agent, nocodazole, which arrests cells in mitosis and has been used to demonstrate that translation rates are strongly reduced (down to 30% of that of asynchronous cells). Using synchronized HeLa cells released from a double thymidine block (G 1/S boundary) or the Cdk1 inhibitor, RO3306 (G 2/M boundary), we have systematically re-addressed this dogma. Using FACS analysis and pulse labeling of proteins with labeled methionine, we now show that translation rates do not slow as cells enter mitosis. This study is complemented by studies employing confocal microscopy, which show enrichment of translation initiation factors at the microtubule organizing centers, mitotic spindle, and midbody structure during the final steps of cytokinesis, suggesting that translation is maintained during mitosis. Furthermore, we show that inhibition of translation in response to extended times of exposure to nocodazole reflects increased eIF2α phosphorylation, disaggregation of polysomes, and hyperphosphorylation of selected initiation factors, including novel Cdk1-dependent N-terminal phosphorylation of eIF4GII. Our work suggests that effects on translation in nocodazole-arrested cells might be related to those of the treatment used to synchronize cells rather than cell cycle status
Feasibility of vocal fold abduction and adduction assessment using cine-MRI
OBJECTIVE: Determine feasibility of vocal fold (VF) abduction and adduction assessment by cine magnetic resonance imaging (cine-MRI) METHODS: Cine-MRI of the VF was performed on five healthy and nine unilateral VF paralysis (UVFP) participants using an axial gradient echo acquisition with temporal resolution of 0.7 s. VFs were continuously imaged with cine-MRI during a 10-s period of quiet respiration and phonation. Scanning was repeated twice within an individual session and then once again at a 1-week interval. Asymmetry of VF position during phonation (VF phonation asymmetry, VFPa) and respiration (VF respiration asymmetry, VFRa) was determined. Percentage reduction in total glottal area between respiration and phonation (VF abduction potential, VFAP) was derived to measure overall mobility. An un-paired t-test was used to compare differences between groups. Intra-session, inter-session and inter-reader repeatability of the quantitative metrics was evaluated using intraclass correlation coefficient (ICC). RESULTS: VF position asymmetry (VFPa and VFRa) was greater (p=0.012; p=0.001) and overall mobility (VFAP) was lower (p=0.008) in UVFP patients compared with healthy participants. ICC of repeatability of all metrics was good, ranged from 0.82 to 0.95 except for the inter-session VFPa (0.44). CONCLUSION: Cine-MRI is feasible for assessing VF abduction and adduction. Derived quantitative metrics have good repeatability. KEY POINTS: • Cine-MRI is used to assess vocal folds (VFs) mobility: abduction and adduction. • New quantitative metrics are derived from VF position and abduction potential. • Cine-MRI able to depict the difference between normal and abnormal VF mobility. • Cine-MRI derived quantitative metrics have good repeatability
Competing source and loss mechanisms due to wave-particle interactions in Earth’s outer radiation belt during the 30 September to 3 October 2012 geomagnetic storm
Abstract Drastic variations of Earth’s outer radiation belt electrons ultimately result from various competing source, loss, and transport processes, to which wave-particle interactions are critically important. Using 15 spacecraft including NASA’s Van Allen Probes, THEMIS, and SAMPEX missions and NOAA’s GOES and POES constellations, we investigated the evolution of the outer belt during the strong geomagnetic storm of 30 September to 3 October 2012. This storm’s main phase dropout exhibited enhanced losses to the atmosphere at L*\u3c 4, where the phase space density (PSD) of multi-MeV electrons dropped by over an order of magnitude in1 MeV electrons and energetic protons, SAMPEX \u3e1 MeV electrons, and ground observations of band-limited Pc1-2 wave activity, we show that this sudden loss was consistent with pitch angle scattering by electromagnetic ion cyclotron waves in the dusk magnetic local time sector at 3\u3c L*\u3c 4. At 4\u3c L*\u3c 5, local acceleration was also active during the main and early recovery phases, when growing peaks in electron PSD were observed by both Van Allen Probes and THEMIS. This acceleration corresponded to the period when IMF Bz was southward, the AE index was \u3e300 nT, and energetic electron injections and whistler-mode chorus waves were observed throughout the inner magnetosphere for \u3e12 h. After this period, Bz turned northward, and injections, chorus activity, and enhancements in PSD ceased. Overall, the outer belt was depleted by this storm. From the unprecedented level of observations available, we show direct evidence of the competitive nature of different wave-particle interactions controlling relativistic electron fluxes in the outer radiation belt
Egg development, hatching rhythm and moult patterns in Paralomos spinosissima (Decapoda: Anomura: Paguroidea: Lithodidae) from South Georgia waters (Southern Ocean)
Larval release, hatching rhythms and moult patterns were examined in a captive population of the subantarctic lithodid, Paralomis spinosissima from the South Georgia and Shag Rocks region. Larvae hatched throughout the year with the majority of females starting to release larvae at the end of the austral summer and beginning of autumn. Larval release continued over a period of up to 9 weeks with high variability in the numbers that hatched each day. A similar seasonal pattern to hatching was evident in the moulting of females. Intermoult period for two adult females (CL = 63 and 85 mm) ranged from 894 to 1,120 days while an intermoult period for males was estimated to be in excess of 832 days. The results are consistent with other species of Paralomis and are discussed in relation to physiological and environmental adaptations to the cold-water conditions south of the Antarctic Convergence
Measurement, Monitoring, and Evaluation of State Demonstrations to Integrate Care for Dual Eligible Individuals: Massachusetts Evaluation Design Plan.
CMS contracted with RTI International to monitor the implementation of all State demonstrations under the Financial Alignment Initiative, and to evaluate their impact on beneficiary experience, quality, utilization, and cost. The evaluation includes an aggregate evaluation and State-specific evaluations. This report describes the State-specific Evaluation Plan for the Massachusetts demonstration as of December 16, 2013. The evaluation activities may be revised if modifications are made to either the Massachusetts demonstration or to the activities described in the Aggregate Evaluation Plan (Walsh et al., 2013). Although this document will not be revised to address all changes that may occur, the annual and final evaluation reports will note areas where the evaluation as executed differs from this evaluation plan. The goals of the evaluation are to monitor demonstration implementation, evaluate the impact of the demonstration on the beneficiary experience, monitor unintended consequences, and monitor and evaluate the demonstration’s impact on a range of outcomes for the eligible population as a whole and for subpopulations (e.g., people with mental illness and/or substance use disorders and long-term services and supports (LTSS) recipients)
Caloric curves and critical behavior in nuclei
Data from a number of different experimental measurements have been used to
construct caloric curves for five different regions of nuclear mass. These
curves are qualitatively similar and exhibit plateaus at the higher excitation
energies. The limiting temperatures represented by the plateaus decrease with
increasing nuclear mass and are in very good agreement with results of recent
calculations employing either a chiral symmetry model or the Gogny interaction.
This agreement strongly favors a soft equation of state. Evidence is presented
that critical excitation energies and critical temperatures for nuclei can be
determined over a large mass range when the mass variations inherent in many
caloric curve measurements are taken into account.Comment: In response to referees comments we have improved the discussion of
the figures and added a new figure showing the relationship between the
effective level density and the excitation energy. The discussion has been
reordered and comments are made on recent data which support the hypothesis
of a mass dependence of caloric curve
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