We present an immersed-boundary algorithm for incompressible flows with complex boundaries, suitable for Cartesian or curvilinear grid system. The key stages of any immersed-boundary technique are ...the interpolation of a velocity field given on a mesh onto a general boundary (a line in 2D, a surface in 3D), and the spreading of a force field from the immersed boundary to the neighboring mesh points, to enforce the desired boundary conditions on the immersed-boundary points. We propose a technique that uses the Reproducing Kernel Particle Method W.K. Liu, S. Jun, Y.F. Zhang, Reproducing kernel particle methods, Int. J. Numer. Methods Fluids 20(8) (1995) 1081–1106 for the interpolation and spreading. Unlike other methods presented in the literature, the one proposed here has the property that the integrals of the force field and of its moment on the grid are conserved, independent of the grid topology (uniform or non-uniform, Cartesian or curvilinear). The technique is easy to implement, and is able to maintain the order of the original underlying spatial discretization. Applications to two- and three-dimensional flows in Cartesian and non-Cartesian grid system, with uniform and non-uniform meshes are presented.
The large-eddy simulation (LES) and Reynolds-averaged Navier-Stokes (RANS) methodologies are used to simulate the air flow inside the container's array geometry of the Mock Urban Setting Test (MUST) ...field experiment. Both tools are assessed and compared in a configuration for which the incident wind direction is perpendicular to the front array. The assessment is carried out against available wind-tunnel data. Effects of including small geometrical irregularities present in the experiments are analysed by considering LES and RANS calculations on two geometries: an idealized one with a perfect alignment and an identical shape of the containers, and a second one including the small irregularities considered in the experiment. These effects are assessed in terms of the local time-mean average and as well in terms of spatial average properties (relevant in atmospheric modelling) given for the velocity and turbulent fields. The structural flow properties obtained using LES and RANS are also compared. The inclusion of geometrical irregularities is found significant on the local time-mean flow properties, in particular the repeated flow patterns encountered in a perfect regular geometry is broken. LES and RANS provide close results for the local mean streamwise velocity profiles and shear-stress profiles, however the LES predictions are closer to the experimental values for the local vertical mean velocity. When considering the spatial average flow properties, the effects of geometrical irregularities are found insignificant and LES and RANS provide similar results.
Large-eddy simulations (LES) and Reynolds-averaged Navier-Stokes (RANS) computations of pollutant dispersion are reported for the Mock Urban Setting Test (MUST) field experiment flow. In particular ...we address the effects of incident wind angle deviation on the mean velocity and on the mean concentration fields. Both computational fluid dynamical methods are assessed by comparing the simulation results with experimental field data. The comparative analysis proposes to relate the plume deflection with the flow channelling effects. The results show that the plume deflection angle varies with the altitude. As the ground is approached the plume is shown to be almost aligned with the street canyon direction and independent of the incident wind directions considered. At higher altitudes well above the obstacles, the plume direction is aligned with the mean wind direction as in dispersion over flat terrain. The near-ground plume deflection is the consequence of a strong channelling effect in the region near the ground. The mean concentration profiles predicted by LES and RANS are both in good qualitative agreement with experimental data but exhibit discrepancies that can be partly explained by the influence of small incident wind angle deviation effects. Compared to RANS, LES predicts a higher channelling and thus a higher deflection of the plume. Results on the fluctuating intensity of the concentration obtained from LES show a satisfactory agreement with experiments. This information is not available from RANS for which only the mean concentration modelling is considered.
Zirconia changes after grinding and regeneration firing Hatanaka, Gabriel R., MSc; Polli, Gabriela S., MSc; Fais, Laiza M.G., PhD ...
The Journal of prosthetic dentistry,
07/2017, Letnik:
118, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract Statement of problem Despite improvements in computer-aided design and computer-aided manufacturing (CAD-CAM) systems, grinding during either laboratory procedures or clinical adjustments is ...often needed to modify the shape of 3 mol(%) yttria-tetragonal zirconia polycrystal (3Y-TZP) restorations. However, the best way to achieve adjustment is unclear. Purpose The purpose of this in vitro study was to evaluate the microstructural and crystallographic phase changes, flexural strength, and Weibull modulus of a 3Y-TZP zirconia after grinding with or without water cooling and regeneration firing. Material and methods Ninety-six bar-shaped specimens were obtained and divided as follows: as-sintered, control; as-sintered with regeneration firing; grinding without water cooling; grinding and regeneration firing with water cooling; and grinding and regeneration firing. Grinding (0.3 mm) was performed with a 150-μm diamond rotary instrument in a high-speed handpiece. For regeneration firing, the specimens were annealed at 1000°C for 30 minutes. The crystalline phases were evaluated by using x-ray powder diffraction. A 4-point bending test was conducted (10 kN; 0.5 mm/min). The Weibull modulus was used to analyze strength reliability. The microstructure was analyzed by scanning electron microscopy. Data from the flexural strength test were evaluated using the Kruskal-Wallis and Dunn tests (α=.05). Results Tetragonal-to-monoclinic phase transformation was identified in the ground specimens; R regeneration firing groups showed only the tetragonal phase. The median flexural strength of as-sintered specimens was 642.0; 699.3 MPa for as-sintered specimens with regeneration firing; 770.1 MPa for grinding and water-cooled specimens; 727.3 MPa for specimens produced using water-cooled grinding and regeneration firing; 859.9 MPa for those produced by grinding; and 764.6 for those produced by grinding and regeneration firing; with statistically higher values for the ground groups. The regenerative firing did not affect the flexural strength. Weibull modulus values ranged from 5.3 to 12.4. The SEM images showed semicircular cracks after grinding. Conclusions Adjustments by grinding in 3Y-TZP frameworks should be performed with water cooling, and regeneration firing should be undertaken to obtain a more reliable material.
Intraocular cancer is a serious threat to the lives of those that suffer from it. Dosimetry for eye brachytherapy presents a significant challenge due to the inherently steep dose gradients that are ...needed to treat such small tumours in close proximity to sensitive normal structures. This issue is addressed by providing much needed quality assurance to eye brachytherapy, a novel volumetric dosimetry system, called Panoptes was developed. This study focuses on the preliminary characterisation and calibration of the system. Using ion beam facilities, the custom, pixelated silicon detector of Panoptes was shown to have good charge collection uniformity and a well defined sensitive volume. Flat-field calibration was conducted on the device using a 250 kVp orthovoltage beam. Finally, the detector and phantom were simulated with Monte Carlo in Geant4, to create water equivalent dose correction factors for each pixel across a range of angles.
•Volumetric detector system produced for plaque brachytherapy.•Orthovoltage, flat-field calibration performed for detector pixels.•Monte Carlo simulation showed mostly little angular deviation across all angles.•Ion beam induced charge collection showed pixels uniform and fully depleted.
ABSTRACT
BACKGROUND
Optimal care delivery requires timely, efficient, and accurate communication among numerous providers and their patients, especially during hospital discharge. Little is known ...about communication patterns during this process.
OBJECTIVE
Our aim was to assess the frequency and patterns of communication between patients and providers during patient discharges from a hospital-based medicine unit.
DESIGN AND APPROACH
On the day of the patient’s discharge, the patient and all healthcare providers involved in the discharge were interviewed using structured questions related to information exchange during the discharge process. Each interview identified the frequency and method of communication between participants, including synchronous (e.g., face-to-face) and asynchronous (e.g., through electronic medical record) routes. Communication patterns were visually diagramed using social network analysis.
PARTICIPANTS
Forty-six patients were screened for inclusion in the network analysis. Of those, seven patients who were fully oriented and able to complete an interview and all providers who participated in their care during the discharge were selected for inclusion in the analysis. In all, 72 healthcare professionals contributing to the discharge process were interviewed, including physicians, nurses, therapists, pharmacists, care coordinators, social workers, and nutritionists.
KEY RESULTS
Patients’ mean age was 63, length-of-stay was 7.8 days, and most (86 %) were discharged to home. On average, 11 roles were involved with each discharge. The majority of communication was synchronous (562 events vs. 469 asynchronous events,
p
= 0.004). Most communication events occurred between the primary nurse and patient and the care coordinator and primary nurse (mean 3.9 and 2.3 events/discharge, respectively). Participants identified intern physicians as most important in the discharge process, followed by primary nurses and care coordinators.
CONCLUSIONS
In patients being discharged from the medicine service, communication was more frequently synchronous, and occurred between intern physicians, primary nurses, and patients. Potential improvements in coordinating patients’ discharges are possible by reorganizing systems to optimize efficient communication.
Summary
This study compared the effectiveness of Ricinus communis (RC) with Nystatin (NYS) and Miconazole (MIC) in the treatment of institutionalised elderly with denture stomatitis (DS). They ...(n = 30) were randomly distributed into three groups: MIC, NYS or RC. Clinical and mycological evaluations were performed prior to the use of the antifungal (baseline) and repeated after 15 and 30 days of treatment. The sample was clinically examined for oral mucosal conditions. Standard photographs were taken of the palate, and the oral candidiasis was classified (Newton's criteria). Mycological investigation was performed by swabbing the palatal mucosa, and Candida spp. were quantified by counting the number of colony‐forming units (cfu mL−1). The clinical and mycological data were analysed, respectively by Wilcoxon and Student's t‐test (α = 0·05). Significant improvement in the clinical appearance of DS in the MIC and RC groups was observed between the 1st and 3rd collections (MIC – P = 0·018; RC – P = 0·011) as well as between the 2nd and 3rd collections (MIC – P = 0·018; RC – P = 0·011). Neither groups showed a statistically significant reduction in cfu mL−1 at any time. Although none of the treatments decreased the cfu mL−1, it was concluded that Ricinus communis can improve the clinical condition of denture stomatitis in institutionalised elderly patients, showing similar results to Miconazole.
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