Compression Process of Pore inside Explosive Charge in a Warhead under Launching Load

In this paper, the compression process of the pore inside explosive charge in a warhead under launching load is simulated and its influence on premature explosion is discussed. The relationship between the pore compression, distortion, and the form of 'igniting hot spot' has been established. The analysis of result indicates that the stress wave in the explosive charge developed due to launching load is a key factor in the pore compression process. The volume change of the pore, which is related to its original volume, is a major factor affecting the form of 'ignition hot spot'. It appears that a specific size of the pore may not lead to the premature explosion of explosive charge in a warhead under launching load. The quantitative relationship between the dangerous size range of the pore and the launching load is a core research subject of warhead safety during launching. With this objective, numerical computing was undertaken to assess the pore's distortion parameter inside the explosive charge of a warhead, and generate database for warhead safety under launching load.Defence Science Journal, 2010, 60(3), pp.244-250, DOI:http://dx.doi.org/10.14429/dsj.60.34

Dispersal patterns of endogenous bacteria among grass carp (Ctenopharyngodon idellus) guts

The formation and regulation of vertebrate endogenous intestinal microbiota has been widely studied as the microbiota plays a crucial role in the host nutrition, development, and health. Despite the importance of microbiota for host health, it is still unclear whether the endogenous intestinal microorganisms are genetically distinct or whether they are genetically related with each other in different host individuals. In the present study, the dispersal situation of the endogenous intestinal bacteria in grass carp was investigated by constructing bacterial 16S rRNA gene clone libraries. The results indicate that the bacteria harbored in the grass carp gut could be separated into the following two groups: a- the private operational taxonomic units (OTUs), which include Cetobacterium somerae, Aeromonas jandaei, Citrobacter freundii, Achromobacter xylosoxidans and Bacteroides species; b- the shared OTUs, which include Vibrio cholerae, Plesiomonas shigelloides and Pasteurella speices. The results obtained in this investigation provide valuable information for assessing the mechanism of spread of the endogenous intestinal bacteria, especially the pathogenic ones. However, the mechanisms involved in different modes of bacterial dispersal in the grass carp gut still require further research

Identifying at-risk patients for sustained atrial high-rate episodes using the c₂ hest score:The west birmingham atrial fibrillation project

BACKGROUND: Sustained atrial high‐rate episodes (SAHREs) among individuals with a cardiac implantable electronic device are associated with an increased risk of adverse outcomes. Risk stratification for the development of SAHREs has never been investigated. We aimed to assess the performance of the C(2)HEST (coronary artery disease or chronic obstructive pulmonary disease [1 point each], hypertension [1 point], elderly [age ≥75 years, 2 points], systolic heart failure [2 points], thyroid disease [1 point]) score in predicting SAHREs in patients with cardiac implantable electronic devices without atrial fibrillation. METHODS AND RESULTS: Five Hundred consecutive patients with cardiac implantable electronic devices in the West Birmingham Atrial Fibrillation Project in the United Kingdom were followed since the procedure to observe the development of SAHREs, defined by atrial high‐rate episodes lasting >24 hours. Risk factors and incidence of SAHREs were analyzed. The predictive value of the C(2)HEST score for SAHRE prediction was evaluated. Over a mean follow‐up of 53.1 months, 44 (8.8%) patients developed SAHREs. SAHREs were associated with higher all‐cause mortality (P<0.001) and ischemic stroke (P=0.001). Age and heart failure were associated with SAHRE occurrence. The incidence of SAHREs increased by the C(2)HEST score (39% higher risk per point increase). Among patients with a C(2)HEST score ≥4, the incidence of SAHREs was 3.62% per year (95% CI, 2.14–5.16). The C(2)HEST score had moderate predictive capability (area under the curve, 0.73; 95% CI, 0.64–0.81) and discriminative ability (log‐rank P=0.003), which was better than other clinical scores (CHA(2)DS(2)‐VASc, CHADS(2), HATCH). CONCLUSIONS: The C(2)HEST score predicted SAHRE incidence in patients without atrial fibrillation who had an cardiac implantable electronic device, with the highest risk seen in patients with a C(2)HEST score ≥4 The benefit of using the C(2)HEST score in clinical practice in this patient population needs further investigation

Seasonal changes in starch content in trophopods of Matteuccia struthiopteris.

Plant science

Reversed Drifting Quasi-periodic Pulsating Structure in an X1.3 Solar Flare on 2005 July 30

Based on the analysis of the microwave observations at frequency of 2.60 -- 3.80 GHz in a solar X1.3 flare event observed at Solar Broadband RadioSpectrometer in Huairou (SBRS/Huairou) on 2005 July 30, an interesting reversed drifting quasi-periodic pulsating structure (R-DPS) is confirmed. The R-DPS is mainly composed of two drifting pulsating components: one is a relatively slow very short-period pulsation (VSP) with period of about 130 -- 170 ms, the other is a relatively fast VSP with period of about 70 -- 80 ms. The R-DPS has a weak left-handed circular polarization. Based on the synthetic investigations of Reuven Ramaty High Energy Solar Spectroscopic Imaging (RHESSI) hard X-ray, Geostationary Operational Environmental Satellite (GOES) soft X-ray observation, and magnetic field extrapolation, we suggest the R-DPS possibly reflects flaring dynamic processes of the emission source regions

Droplet entrainment within the evaporator to the suitable volume-filling ratio of a vertical two-phase closed thermosyphon

The present study on vertical two-phase closed thermosyphon (TPCT) is aimed to determine the suitable volume-filling ratio, as a function of geometries, heat flux and vapor temperature, in order to avoid the potential local dryout in the evaporator section and hence to maximize the performance. In the study, the droplet entrainment, which is caused by the internal counter flow during the nucleate boiling within the falling liquid film in the evaporator section, is introduced to improve the existing TPCT model, so a comprehensive model with considering all three heat transfer regimes in the evaporator is further established. The suggested lower and upper limits of volume-filling ratio (CFR and EFR) are then determined by utilizing the criterias for local dryout, flooding limit and boiling limit. Furthermore, the effects of geometries, heat flux and vapor temperature on the range of volume-filling ratio are analyzed in details, a simplified correlation of CFR is then proposed based on the numerical modeling results. Particularly, the predictions of the distribution of falling film thickness and onset of flooding are validated with the published experimental data and other numerical simulation results. It is also found that the droplet entrainment significantly influences the thickness and distribution of the falling film. Increasing vapor temperature and inner diameter and decreasing the evaporator length significantly enlarge the volume-filling ratio range (between CFR and EFR), operation envelope (corresponding to boiling limit and flooding limit) of TPCT. Increasing the condenser length increases the volume-filling ratio range and operation envelope to a small extent. The influence mechanisms of the optimum filling ratio by the heat flux and geometries are complicated; however, a correlation of CFR can be obtained in a good agreement with the numerical modeling results within 30% deviation for the whole limited scope

Acoustic and relaxation processes in supercooled o-ter-phenyl by optical-heterodyne transient grating experiment

The dynamics of the fragile glass-forming o-ter-phenyl is investigated by time-resolved transient grating experiment with an heterodyne detection technique in a wide temperature range. We investigated the dynamics processes of this glass-former over more then 6 decades in time with an excellent signal/noise. Acoustic, structural and thermal relaxations have been clearly identify and measured in a time-frequency window not covered by previous spectroscopic investigations. A detailed comparison with the density response function, calculated on the basis of generalized hydrodynamics model, has been worked out

Oral Anticoagulants for Nonvalvular Atrial Fibrillation in Patients with High Risk of Gastrointestinal Bleeding

IMPORTANCE: Many patients with nonvalvular atrial fibrillation (NVAF) are at a high risk of gastrointestinal (GI) bleeding due to conditions including older age; stage III to V chronic kidney disease (CKD); HAS-BLED (hypertension, kidney or liver disease, stroke history, prior bleeding, unstable international normalized ratio, age >65, drug or alcohol use) score of 3 or greater; corticosteroid, antiplatelet or nonsteroidal anti-inflammatory drug (NSAID) use; or GI conditions. OBJECTIVE: To compare the risk of stroke and/or systemic embolism (SE) and major bleeding (MB) among patients with NVAF and high risk of GI bleeding who received non–vitamin K antagonist oral anticoagulants (NOACs) vs those who received warfarin. DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study included patients with NVAF who were 75 years and older; had stage III to V CKD; had an HAS-BLED score of 3 or greater; used corticosteroids, antiplatelets, or NSAIDs; or had GI conditions. Data were collected from the Centers for Medicare & Medicaid Services and 4 commercial insurance databases between January 1, 2012, and September 30, 2015. Data analysis was conducted from January 2012 to September 2015. EXPOSURES: New prescription for apixaban, dabigatran, rivaroxaban, or warfarin between January 1, 2013, and September 30, 2015 (identification period). MAIN OUTCOMES AND MEASURES: Six propensity score–matched cohorts were created to compare between study drugs. For the primary objective, Cox models were used to estimate stroke and/or SE and MB hazard ratios (HRs). RESULTS: A total of 381 054 patients (187 489 [49.2%] women) with NVAF and at least 1 high-risk GI bleeding factor were identified (HAS-BLED score ≥3: 284 527 [74.7%]; aged ≥75 years: 252 835 [66.4%]; corticosteroid, antiplatelet, or NSAID therapy: 107 675 [28.3%]; prior GI bleeding conditions: 74 818 [19.6%]; and stage III-V CKD: 56 892 [14.9%]). All NOACs were associated with a lower risk of stroke and/or SE vs warfarin (apixaban: HR, 0.60; 95% CI, 0.52-0.68; dabigatran: HR, 0.75; 95% CI, 0.64-0.88; rivaroxaban: HR, 0.79; 95% CI, 0.73-0.86). Compared with warfarin, apixaban and dabigatran were associated with a lower risk of MB (apixaban: HR, 0.59; 95% CI, 0.56-0.63; dabigatran: HR, 0.78; 95% CI, 0.70-0.86), while rivaroxaban was associated with a higher risk (HR, 1.11; 95% CI, 1.05-1.16). CONCLUSIONS AND RELEVANCE: In this study of patients with NVAF and high risk of GI bleed, NOACs were associated with lower rates of stroke and/or SE, but NOACs had varying risks of MB compared with warfarin. These results may help inform treatment options in this patient population

Mass measurements of neutron-deficient Y, Zr, and Nb isotopes and their impact on rp and νp nucleosynthesis processes

© 2018 The Authors. Published by Elsevier B.V. This manuscript is made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International licence (CC BY-NC-ND 4.0). For further details please see: https://creativecommons.org/licenses/by-nc-nd/4.0/Using isochronous mass spectrometry at the experimental storage ring CSRe in Lanzhou, the masses of 82Zr and 84Nb were measured for the first time with an uncertainty of ∼10 keV, and the masses of 79Y, 81Zr, and 83Nb were re-determined with a higher precision. The latter are significantly less bound than their literature values. Our new and accurate masses remove the irregularities of the mass surface in this region of the nuclear chart. Our results do not support the predicted island of pronounced low α separation energies for neutron-deficient Mo and Tc isotopes, making the formation of Zr–Nb cycle in the rp-process unlikely. The new proton separation energy of 83Nb was determined to be 490(400) keV smaller than that in the Atomic Mass Evaluation 2012. This partly removes the overproduction of the p-nucleus 84Sr relative to the neutron-deficient molybdenum isotopes in the previous νp-process simulations.Peer reviewe