94 research outputs found
Two-Phase Flow in Circular Secondary Sedimentation Tanks
The main objective of this work was to optimise a numerical model to predict the
flow in circular secondary sedimentation tanks. The numerical models in the
literature were reviewed and the new opportunities for research were identified.
Single-phase flow characteristics of two circular sedimentation tanks were
investigated using the CFD program, CFX-F3D. The flow in the circular clarifiers
were modelled in two dimensions (axial and radial) and using the standard k-E
turbulence model. Results indicated that a vertical inlet instead of a horizontal inlet
did not improve the correlation with the experimental data in a pilot-scale tank.
Modelling the diurnal variation in flow to a full-scale tank significantly improved
the correlation with experimental data. The `Eulerian multi-fluid' model in the
program, CFX-F3D was modified to predict the flow in circular secondary
sedimentation tanks. The model compared quite closely with the measured
residence time of the effluent and return activated sludge (RAS) in a conventional
secondary clarifier. The residence time of the effluent in another secondary
clarifier with a turbulent jet, was over-predicted. The mean particle diameter in the
model was found by comparing the numerical predictions with experimental data.
The particle diameter was between 100 to 190 μm for the secondary clarifiers,
which was in agreement with the experimental data in the literature. The flow
patterns in the conventional secondary clarifier were affected by the particle
density, particle diameter, axial slip velocity, colloids settling parameter, axial
turbulent Prandtl number, inlet flow rate and inlet solids concentration. A 3-D
simulation of the conventional secondary clarifier was in agreement with a 2-D
simulation. Recommended values were given for all these parameters. However,
the drag force between the phases was not formulated correctly and the water
surface was modelled as a symmetry plane. Therefore, some more work is still
required to make suitable modifications to the model
Neural Variational Inference For Estimating Uncertainty in Knowledge Graph Embeddings
Recent advances in Neural Variational Inference allowed for a renaissance in
latent variable models in a variety of domains involving high-dimensional data.
While traditional variational methods derive an analytical approximation for
the intractable distribution over the latent variables, here we construct an
inference network conditioned on the symbolic representation of entities and
relation types in the Knowledge Graph, to provide the variational
distributions. The new framework results in a highly-scalable method. Under a
Bernoulli sampling framework, we provide an alternative justification for
commonly used techniques in large-scale stochastic variational inference, which
drastically reduce training time at a cost of an additional approximation to
the variational lower bound. We introduce two models from this highly scalable
probabilistic framework, namely the Latent Information and Latent Fact models,
for reasoning over knowledge graph-based representations. Our Latent
Information and Latent Fact models improve upon baseline performance under
certain conditions. We use the learnt embedding variance to estimate predictive
uncertainty during link prediction, and discuss the quality of these learnt
uncertainty estimates. Our source code and datasets are publicly available
online at
https://github.com/alexanderimanicowenrivers/Neural-Variational-Knowledge-Graphs.Comment: Accepted at IJCAI 19 Neural-Symbolic Learning and Reasoning Worksho
Experimental study of the collision 11Be + 64Zn around the Coulomb barrier
In this paper details of the experimental procedure and data analysis of the collision of 11Be+64Zn around the Coulomb barrier are described and discussed in the framework of different theoretical approaches. In a previous work [ A. Di Pietro et al. Phys. Rev. Lett. 105 022701 (2010)], the elastic scattering angular distribution of the collisions 9, 10Be+64Zn as well as the angular distribution for the quasielastic scattering and transfer/breakup cross sections for the 11Be+64Zn reaction were briefly reported. The suppression of the quasielastic angular distribution in the Coulomb-nuclear interference angular region observed in the collision of the 11Be halo nucleus with respect to the other two beryllium isotopes was interpreted as being caused by a long-range absorption owing to the long decay length of the 11Be wave function. In this paper, new continuum-discretized coupled-channel calculations of the 11Be+64Zn reaction are reported in the attempt to interpret the effect of coupling with the breakup channels on the measured cross sections. The calculations show that the observed suppression of the Coulomb-nuclear interference peak is caused by a combined effect of Coulomb and nuclear couplings to the breakup channels
Completeness and Changes in Registered Data and Reporting Bias of Randomized Controlled Trials in ICMJE Journals after Trial Registration Policy
We assessed the adequacy of randomized controlled trial (RCT) registration, changes to registration data and reporting completeness for articles in ICMJE journals during 2.5 years after registration requirement policy.For a set of 149 reports of 152 RCTs with ClinicalTrials.gov registration number, published from September 2005 to April 2008, we evaluated the completeness of 9 items from WHO 20-item Minimum Data Set relevant for assessing trial quality. We also assessed changes to the registration elements at the Archive site of ClinicalTrials.gov and compared published and registry data.RCTs were mostly registered before 13 September 2005 deadline (n = 101, 66.4%); 118 (77.6%) started recruitment before and 31 (20.4%) after registration. At the time of registration, 152 RCTs had a total of 224 missing registry fields, most commonly 'Key secondary outcomes' (44.1% RCTs) and 'Primary outcome' (38.8%). More RCTs with post-registration recruitment had missing Minimum Data Set items than RCTs with pre-registration recruitment: 57/118 (48.3%) vs. 24/31 (77.4%) (χ(2) (1) = 7.255, P = 0.007). Major changes in the data entries were found for 31 (25.2%) RCTs. The number of RCTs with differences between registered and published data ranged from 21 (13.8%) for Study type to 118 (77.6%) for Target sample size.ICMJE journals published RCTs with proper registration but the registration data were often not adequate, underwent substantial changes in the registry over time and differed in registered and published data. Editors need to establish quality control procedures in the journals so that they continue to contribute to the increased transparency of clinical trials
Evidence of strong effects of the 11Be halo structure on reaction processes at energies around the Coulomb barrier
The collision induced by the three Beryllium isotopes, 9, 10, 11Be, on 64Zn target were investigated at Ec.m. ≈ 1.4 the Coulomb barrier. Elastic scattering angular distributions were measured for the 9, 10Be collisions whereas, in the 11Be case the quasielastic scattering angular distribution was obtained. A strong damping of the quasielastic cross-section was observed in the 11Be case, especially in the angular range around the Coulomb-nuclear interference peak. In this latter case a large total-reaction cross-section is found, more than a factor of two larger than the ones extracted in the reactions induced by the non-halo Beryllium isotopes. A large contribution to the total-reaction cross-section in the 11Be case could be attributed to transfer and/or break-up events
Elastic Scattering and Reaction Mechanisms of the Halo Nucleus 11Be around the Coulomb Barrier
Collisions induced by 9, 10, 11Be on a 64Zn target at the same c.m. energy were studied. For the first time, strong effects of the 11Be halo structure on elastic-scattering and reaction mechanisms at energies near the Coulomb barrier are evidenced experimentally. The elastic-scattering cross section of the 11Be halo nucleus shows unusual behavior in the Coulomb-nuclear interference peak angular region. The extracted total-reaction cross section for the 11Be collision is more than double the ones measured in the collisions induced by 9, 10Be. It is shown that such a strong enhancement of the total-reaction cross section with 11Be is due to transfer and breakup processes
Structure of 24Mg excited states and their influence on nucleosynthesis
The main idea of the two presented experiments is to study the decay of resonances in 24Mg at excitation energies above the 12C+12C decay thresh- old, in the astrophysical energy region of interest. The measurement of the 12C(16O,α)24Mg* reaction was performed at INFN-LNS in Catania. Only the α+20Ne decay channel of 24Mg is presented here, because it was a motivation for conducting a new experiment, a study of the 4He(20Ne,4He)20Ne reaction, performed at INFN-LNL in Legnaro. Some preliminary results of this measurement are also presented
Иммуномодулирующие эффекты ингаляций ультра низких доз алкилирующего цитостатика мелфалана у больных бронхиальной астмой
Melphalan (Alkeran) is an alkylating drug belonging to the nitrogen mustard family. It is known as cytostatic and immunosuppressive agent. Cytostatic effect of melphalan can be realized in the dose range of 0.6 to 1.4 mg/kg bodyweight or in the concentration of 0.1 mg/ml in vitro. At the same time the 100-fold lower concentrations of the alkylating agents still demonstrate their properties resulted from a selective block of cytokine receptors. Forty two patients with exacerbation of steroid-resistant asthma were enrolled into the trial. Twenty one subjects were treated with basic therapy only (the control group) and 21 others received the basic therapy and melphalan inhalations (0.1 mg daily). Inflammatory markers of the bronchoalveolar lavage fluid and blood were investigated. The combined therapy with melphalan provided a significant benefit compared with the basic therapy alone. Marked elevation in the bronchoalveolar lavage fluid cytokine level was observed in the patients treated with melphalan. This could be associated with the airway epithelium regeneration. A significant decrease in CD95 expression by the blood lymphocytes as well as a diminution of the lymphocyte resistance to glucocorticoids was also demonstrated.Мелфалан (Алкеран®) представляет собой алкилирующий препарат, относящийся к семейству азотистых ипритов и обладающий выраженной цитостатической и иммунодепрессивной активностью. Цитостатический эффект мелфалана обнаруживается в дозах 0,6-1,4 мг/кг или в концентрации 0,1 мг/мл в опытах in vitro. В то же время при снижении концентрации в 100 раз и более алкилирующие препараты продолжают обнаруживать биологическую активность, которая является результатом селективной блокады цитокиновых рецепторов. В исследование были включены 42 пациента с тяжелой бронхиальной астмой. Половина больных получала стандартную терапию (контрольная группа), а другой половине дополнительно ингалировали мелфалан (0,1 мг в день). У всех больных исследовали динамику маркеров воспаления в бронхиальном смыве и периферической крови. Показано, что комбинация базисной терапии и ингаляций мелфалана давала существенно более благоприятный эффект, чем стандартные методы лечения. В образцах бронхиального смыва было обнаружено заметное повышение уровня цитокинов, что может быть связано с регенерацией эпителия бронхов, признаки которой ранее были обнаружены при морфологическом исследовании. В периферической крови было обнаружено значимое снижение числа клеток, экспрессирующих CD95, а также повышение чувствительности лимфоцитов к антипролиферативному действию глюкокортикоидов
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