The paper presents an assessment of the performance of a variety of turbulence models in simulating buoyancy-aided, turbulent mixed convection in vertical pipes. This has been done by comparison of ...RANS predictions with DNS results already available in the literature. Both the RANS and the DNS studies were conducted for conditions of constant and uniform fluid properties with the influence of buoyancy being accounted for using the Boussinesq approximation. This eliminated effects of non-uniformity of properties other than through the action of buoyancy and enabled its influence to be considered in isolation. In the course of the study, the turbulence models have been classified into two groups, namely, those which were able to capture the main features of buoyancy-influenced heat transfer (Group one) and those that were not able to do so (Group two). Common features in model formulation have been identified for each group. It is shown that the response to buoyancy of commonly-used controlling parameters in turbulence damping functions varies significantly and that the performance of a model can largely be correlated with the type of controlling parameter used. A significant defect of the Group-one models which has been identified is that they continue to predict that the ‘viscous sub-layer’ remains thick as a result of the influence of buoyancy even when the velocity profile has been distorted to an extent that it has become inverted in the core, whereas DNS data clearly show that this is not the case. The use of different methodologies for modelling direct production of turbulence through the direct action of buoyancy has been shown to have little effect on predictions of mixed convection in vertical flows because the effect of buoyancy on turbulence is predominantly due to the indirect effect.
Digital dental articulation for three-piece maxillary orthognathic surgery is challenging. The purpose of this proof-of-concept study was to evaluate the clinical feasibility of a newly developed ...mathematical algorithm to digitally establish the final occlusion for three-piece maxillary surgery. Five patients with jaw deformities who had undergone a three-piece double-jaw surgery that was planned virtually were randomly selected for this study. The final occlusion had been hand-articulated using stone casts, scanned into the computer and used in the surgery. These hand-articulated occlusions served as the control group. To form the experimental group, the three-piece maxillary dental arch was articulated again automatically from the patient’s original occlusion using the mathematical algorithm. The hand- and algorithm-articulated occlusions were then evaluated qualitatively by two experienced orthodontists. A quantitative evaluation was also performed. The results of the qualitative evaluation showed that all of the three-piece occlusions, hand- and algorithm-articulated, were clinically acceptable based on the American Board of Orthodontics grading system. When compared, two of the algorithm-articulated occlusions were clearly better (40%), one was the same (20%), and two were slightly worse (40%) than the hand-articulated occlusions. All of the quantitative measurements were comparable between the two articulation methods. In conclusion, the results of this study demonstrate that it is clinically feasible to digitally articulate the three-piece maxillary arch to the intact mandibular dental arch.
Abstract
Interstellar neutral atoms propagating into the heliosphere experience charge exchange with the supersonic solar wind (SW) plasma, generating ions that are picked up by the SW. These pickup ...ions (PUIs) constitute ∼25% of the proton number density by the time they reach the heliospheric termination shock (HTS). Preferential acceleration of PUIs at the HTS leads to a suprathermal, kappa-like PUI distribution in the heliosheath, which may be further heated in the heliosheath by traveling shocks or pressure waves. In this study, we utilize a dynamic, 3D magnetohydrodynamic model of the heliosphere to show that dynamic heating of PUIs at the HTS and in the inner heliosheath (IHS), as well as a background source of energetic neutral atoms (ENAs) from outside the heliopause, can explain the heliospheric ENA signal observed by the Interstellar Boundary Explorer (IBEX) in the Voyager 2 direction. We show that the PUI heating process at the HTS is characterized by a polytropic index larger than 5/3, likely ranging between
γ
∼ 2.3 and 2.7, depending on the time in solar cycle 24 and SW conditions. The ENA fluxes at energies >1.5 keV show large-scale behavior in time with the solar cycle and SW dynamic pressure, whereas ENAs < 1.5 keV primarily exhibit random-like fluctuations associated with SW transients affecting the IHS. We find that ≲20% of the ENAs observed at ∼0.5–6 keV come from other sources, likely from outside the heliopause as secondary ENAs. This study offers the first model replication of the intensity and evolution of IBEX-Hi ENA observations from the outer heliosphere.
Summary
Little is known about post-acute care following hip fracture surgery. We investigated discharge destinations from surgical hospitals for nine Canadian provinces. We identified significant ...heterogeneity in discharge patterns across provinces suggesting different post-acute recovery pathways. Further work is required to determine the impact on patient outcomes and health system costs.
Introduction
To examine discharge destinations by provinces in Canada, adjusting for patient, injury, and care characteristics.
Methods
We analyzed population-based hospital discharge abstracts from a national administrative database for community-dwelling patients who underwent hip fracture surgery between 2004 and 2012 in Canada. Discharge destination was categorized as rehabilitation, home, acute care, and continuing care. Multinomial logistic regression modeling compared proportions of discharge to rehabilitation, acute care, and continuing care versus home between each province and Ontario. Adjusted risk differences and risk ratios were estimated.
Results
Of 111,952 previously community-dwelling patients aged 65 years or older, 22.5% were discharged to rehabilitation, 31.6% to home, 27.0% to acute care, and 18.2% to continuing care, with significant variation across provinces (
p
< 0.001). The proportion of discharge to rehabilitation ranged from 2.4% in British Columbia to 41.0% in Ontario while the proportion discharged home ranged from 20.3% in Prince Edward Island to 52.2% in British Columbia. The proportion of discharge to acute care ranged from 15.2% in Ontario to 58.8% in Saskatchewan while the proportion discharged to continuing care ranged from 9.3% in Manitoba and Prince Edward Island to 22.9% in New Brunswick. Adjusting for hospital type changed the direction of the provincial effect on discharge to continuing care in two provinces, but statistical significance remained consistent with the primary analysis.
Conclusions
Discharge destination from the surgical hospital after hip fracture is highly variable across nine Canadian provinces. Further work is required to determine the impact of this heterogeneity on patient outcomes and health system costs.
Although ZnO and ZnS are chemically and structurally similar, these binary compounds do not form a solid solution at room temperature for all proportions of sulfur (S) and oxygen (O) due to ...solubility limits of S in ZnO and O in ZnS in equilibrium states. To fabricate ZnO1−xSx thin films with 0<x<1, films were intentionally deposited in a non-equilibrium state using pulsed laser deposition while controlling oxygen pressures. The deposited ZnO1−xSx thin film structures were investigated by X-ray diffraction, confirming the formation of hexagonal wurtzite structures with c-axis lattice constants larger than that of ZnO and smaller than that of ZnS. Furthermore, phase segregation to ZnO and ZnS was observed by increasing the temperature of the ZnO0.5S0.5 thin film, suggesting non-equilibrium state of the deposited film. The observed optical energy bandgaps of the ZnO1−xSx thin films were smaller than those of both ZnO (~3.3eV) and ZnS (~3.68eV), suggesting a bandgap bowing effect due to valance and conduction band shifts.
•We successfully deposited a II–VI type of semiconductors, ZnO1−xSx thin films.•We study about ZnO0.5S0.5 phase with temperature dependent XRD.•The contents of ZnO1−xSx thin films are from 1(ZnS) to 0(ZnO).
Glioblastoma is a common primary brain tumor with a poor but variable prognosis. Our aim was to investigate the feasibility of MR perfusion imaging by using arterial spin-labeling for determining the ...prognosis of patients with glioblastoma.
Pseudocontinuous arterial spin-labeling with 3D background-suppressed gradient and spin-echo was acquired before surgery on 53 patients subsequently diagnosed with glioblastoma. The calculated CBF color maps were visually evaluated by 3 independent readers blinded to patient history. Pathologic and survival data were correlated with CBF map findings. Arterial spin-labeling values in tumor tissue were also quantified by using manual fixed-size ROIs.
Two perfusion patterns were characterized by visual evaluation of CBF maps on the basis of either the presence (pattern 1) or absence (pattern 2) of substantial hyperperfused tumor tissue. Evaluation of the perfusion patterns was highly concordant among the 3 readers (κ = 0.898, P < .001). Pattern 1 (versus pattern 2) was associated with significantly shorter progression-free survival by Kaplan-Meier analysis (median progression-free survival of 182 days versus 485 days, P < .01) and trended with shorter overall survival (P = .079). There was a significant association between pattern 1 and epidermal growth factor receptor variant III expression (P < .01).
Qualitative evaluation of arterial spin-labeling CBF maps can be used to stratify survival and predict epidermal growth factor receptor variant III expression in patients with glioblastoma.
The Jovian Auroral Distributions Experiment ion sensor (JADE‐I) on board the National Aeronautics and Space Administration's Juno mission measured solar wind ions for ≈40 days prior to the ...spacecraft's arrival at Jupiter, simultaneous with numerous telescope observations of the Jovian aurora. JADE‐I is a thermal plasma time‐of‐flight instrument designed to measure Jovian auroral and magnetospheric ions. This study provides a solar wind parameter data set for the approach phase that may be used in coordinated studies with remote measurements of the Jovian aurora, to compare with models that propagate solar wind conditions from Earth and to apply to Jovian bow shock or magnetopause models. While multiple bow shock crossings were predicted during Juno's approach, there was only one observed suggesting a compressed magnetosphere that was shrinking as Juno approached. However, the calculated ram pressure at the bow shock was near the median value of those 40 days, rather than being in an upper percentile.
Key Points
A technique to extract solar wind flow and density from coarse energy and field of view particle measurements is developed
Solar wind parameters for Juno's approach to the Jovian system are derived
On approach Juno made a single bow shock crossing, rather than predicted multiple crossings
The LIGO detection of the gravitational wave transient GW150914, from the inspiral and merger of two black holes with masses ≳30M_{⊙}, suggests a population of binary black holes with relatively high ...mass. This observation implies that the stochastic gravitational-wave background from binary black holes, created from the incoherent superposition of all the merging binaries in the Universe, could be higher than previously expected. Using the properties of GW150914, we estimate the energy density of such a background from binary black holes. In the most sensitive part of the Advanced LIGO and Advanced Virgo band for stochastic backgrounds (near 25 Hz), we predict Ω_{GW}(f=25 Hz)=1.1_{-0.9}^{+2.7}×10^{-9} with 90% confidence. This prediction is robustly demonstrated for a variety of formation scenarios with different parameters. The differences between models are small compared to the statistical uncertainty arising from the currently poorly constrained local coalescence rate. We conclude that this background is potentially measurable by the Advanced LIGO and Advanced Virgo detectors operating at their projected final sensitivity.
A variety of surface observational techniques including full-field strain mapping based on digital image correlation analysis, electron back-scatter diffraction and in situ field emission scanning ...electron microscopy have been used to follow the patterns of inhomogeneous flow which occur during tensile testing of AA5754. The observations permit the relationships between slip lines, dynamic strain aging, shear localization, diffuse and localized necking to be delineated. In addition, fracture observation and metallographic assessment of damage processes have been conducted to enable an understanding of the relationship between inhomogeneous deformation and ductility to be developed.
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