Optimization of Flapping Airfoils for Maximum Thrust and Propulsive Efficiency

A numerical optimization algorithm based on the steepest decent along the variation of the optimization function is implemented for maximizing the thrust and/or propulsive efficiency of a single flapping airfoil. Unsteady, low speed laminar flows are computed using a Navier-Stokes solver on moving overset grids. The flapping motion of the airfoil is described by a combined sinusoidal plunge and pitching motion. Optimization parameters are taken to be the amplitudes of the plunge and pitching motions, and the phase shift between them. Computations are performed in parallel in a work station cluster. The numerical simulations show that high thrust values may be obtained at the expense of reduced efficiency. For high efficiency in thrust generation, the induced angle of attack of the airfoil is reduced and large scale vortex formations at the leading edge are prevented.

Online Fault Classification in HPC Systems through Machine Learning

As High-Performance Computing (HPC) systems strive towards the exascale goal, studies suggest that they will experience excessive failure rates. For this reason, detecting and classifying faults in HPC systems as they occur and initiating corrective actions before they can transform into failures will be essential for continued operation. In this paper, we propose a fault classification method for HPC systems based on machine learning that has been designed specifically to operate with live streamed data. We cast the problem and its solution within realistic operating constraints of online use. Our results show that almost perfect classification accuracy can be reached for different fault types with low computational overhead and minimal delay. We have based our study on a local dataset, which we make publicly available, that was acquired by injecting faults to an in-house experimental HPC system.Comment: Accepted for publication at the Euro-Par 2019 conferenc

Electrocardiographic findings of carbon monoxide intoxication; two cases

IntroductionCarbon monoxide (CO) poisoning is a life threatening emergency. Oxygen delivery to tissues is reduced and hypoxia develops. Most affected systems are the central nervous system and cardiovascular system. For the diagnosis of CO poisoning, first poisoning should be suspected and then blood carboxyhaemoglobin (COHb) levels should be measured. For cardiovascular evaluation ECG is required.Case 1A 56-year-old male patient admitted to ED with complaints of syncope, headache, dizziness and blurred vision. Patient was mentally confused and on ECG sinus tachycardia was present (Fig. 1). On blood gas analysis COHb value was measured 33.3%. Due to syncope and ECG changes hyperbaric oxygen (HBO) therapy initiated. After the treatment, COHb value was measured 4.5% and ECG showed normal sinus rhythm. Patient was discharged with recommendations.Case 2An unconscious 36-year-old female patient admitted to ED with a diagnosis of CO poisoning. ECG revealed ST depression on DII-DIII-AVF leads (Fig. 2) and elevated troponin I (0.1ng/ml) and CK-MB (47U/L) values were determined. On blood gas analysis, COHb value was measured 39.8%. HBO therapy initiated. After HBO therapy patient was conscious and for further follow-up patient was admitted to intensive care unit.Discussion and ConclusionAlthough there is no classic ”carbon monoxide” ECG pattern, sinus tachycardia and ST-T depressions are the most common ECG findings. Even a small amount of exposure to CO can cause myocardial infarction, especially in patients with coronary artery disease. Patients admitting to ED with chest pain and ECG changes may be considered as a possible CO poisoning and patients with CO poisoning must be carefully evaluated for cardiovascular disease

A review of Morgagni and Bochdalek hernias in adults

The incidence of Bochdalek and Morgagni hernias among adults is very rare. The purpose of this study was to determine retrospectively the prevalence and characteristics of adult Bochdalek and Morgagni hernias in a decade. Consequently, we demonstrated 12 patients with Bochdalek and 8 patients with Morgagni hernias. We presented plain radiography, operation images, and computed tomography findings of an adult patient with symptoms due to Bochdalek and Morgagni hernias. In surgical repair, the Morgagni hernia is best approached via laparotomy, and the Bochdalek hernia can be treated through thoracotomy or laparotomy. (Folia Morphol 2011; 70, 1: 5-12

The effects of quercetin on liver regeneration after liver resection in rats

The aim of the present study was to assess the influence of quercetine (QE) on liver regeneration after partial hepatectomy (PH) in rats. A total of 24 male Wistar albino rats were divided into three groups: sham-operated (SH), PH and PH+QE; each group contain 8 animals. The rats in QE-treated groups were given QE (15 mg/kg body weight) once a day i.p., for 7 days starting 3 days prior to hepatectomy operation. At 7 days after resection, liver samples were collected. The malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione (GSH) levels were estimated in liver homogenates. Moreover, histopathological examination, mitotic index (MI), proliferating cell nuclear antigen labelling, proliferation index (PI), transferase-mediated dUTP nick end-labelling assay, apoptotic index (AI) were evaluated at 7 days after hepatectomy. As a result, QE significantly increased MI, PI, and significantly decreased AI in PH rats. Additionally, QE remarkably inhibited the elevation of MDA, restored impaired antioxidant SOD activity and GSH level, and also attenuated hepatic vacuolar degeneration and sinusoidal congestion. These results suggested that QE treatment had a beneficial effect on liver regenerative capacity of the remnant liver tissue after hepatectomy, probably due to its antioxidative, antiapoptotic and proliferative property

Effects of nicotine administration in rats on MMP2 and VEGF levels in periodontal membrane

Background: Nicotine is associated with increased incidence of periodontal disease and poor response to therapy. This article aimed at identifying the expression of matrix metalloproteinases 2 (MMPs2) and vascular endothelial growth factor (VEGF) proteins on extracellular matrix, fibrous distribution and angiogenetic development in periodontitis caused by nicotine effects on periodontal membrane.Materials and methods: In this experimental study, rats were divided into nicotine and control groups. While the rats in the nicotine group (n = 6) were administered 2 mg/kg nicotine sulphate for 28 days, the animals in the control group (n = 6) were only administered 1.5 mL physiologic saline solution subcutaneously for 28 days.Results: Histological sections were prepared and immunohistochemically stained for MMP2 and VEGF. The sections stained with Trichrome-Masson were observed under light microscope. VEGF and MMP2 immunoreactivity of periodontal gingiva and dentin was assessed by immunohistochemical staining.Conclusions: Nicotine reduces MMP production, disrupts collagen synthesis and causes periodontitis. We observed that nicotine increases periodontitis by disrupting periodontal membrane and prevents tooth to anchor in dental alveoli by disrupting epithelial structure

Comparison of First 50 and Subsequent 74 Surgeries of Transcanalicular Laser Dacryocystorhinostomy Performed by a Surgeon Team

Abstract Purpose: To compare perioperative and postoperative outcomes of the first and following 50 cases of transcanalicular laser dacryocystorhinostomy performed by a surgeon team. Methods: Results of 124 eyes of 115 patients who had a diagnosis of distal obstruction of the lacrimal drainage system and underwent transcanalicular laser dacryocystorhinostomy procedures were retrospectively detected. Initial 50 eyes were considered as group 1; 74 following eyes were accepted as group 2. Groups were compared regarding age, gender, total surgical time, time for creation of osteotomy, pain score, bleeding score, anatomic and functional success rates. Results: The average total surgical time was 43.2 ± 6.0 minutes (range: 31 to 65 minutes) in group 1, and 30.0 ± 6.4 minutes (range: 21 to 57 minutes) in group 2 (p < 0.001). Laser osteotomy creation required 25.0 ± 4.2 minutes (range: 14 to 34 minutes) in group 1, and 14.6 ± 3.6 months (range: 9 to 28 minutes) (p < 0.001). Intraoperative pain and bleeding scores were significantly better in group 2 (p < 0.001 and p < 0.001 respectively). Success rate was 54.0% in group 1, and 85.1% in group 2 (p < 0.001). Conclusion: The results of current study clearly showed that increased experience of a surgeon results with improvement of better surgical outcomes. Initial studies about a novel technique should make clear if the study cases are the beginning cases of the authors

Fractional Equations of Curie-von Schweidler and Gauss Laws

The dielectric susceptibility of most materials follows a fractional power-law frequency dependence that is called the "universal" response. We prove that in the time domain this dependence gives differential equations with derivatives and integrals of noninteger order. We obtain equations that describe "universal" Curie-von Schweidler and Gauss laws for such dielectric materials. These laws are presented by fractional differential equations such that the electromagnetic fields in the materials demonstrate "universal" fractional damping. The suggested fractional equations are common (universal) to a wide class of materials, regardless of the type of physical structure, chemical composition or of the nature of the polarization.Comment: 11 pages, LaTe

A Novel Alternating Cell Directions Implicit Method for the Solution of Incompressible Navier Stokes Equations on Unstructured Grids

In this paper, A Novel Alternating Cell Direction Implicit Method (ACDI) is researched which allows implementation of fast line implicit methods on quadrilateral unstructured meshes. In ACDI method, designated alternating cell directions are taken along a series of contiguous cells within the unstructured grid domain and used as implicit lines similar to Line Gauss Seidel Method (LGS). ACDI method applied earlier for the solution of potential flows is extended for the solution of the incompressible Navier-Stokes equations on unstructured grids. The system of equations is solved by using the Symmetric Line Gauss-Seidel (SGS) method along the alternating cell directions. Laminar flow fields over a single element NACA-0008 airfoil are computed by using structured and unstructured quadrilateral grids, and inviscid Euler flow solutions are given for the NACA-23012b multielement airfoil. The predictive capability of the method is validated against the data taken from the experimental or the other numerical studies and the efficiency of the ACDI method is compared with the implicit Point Gauss Seidel (PGS) method. In the selected validation cases, the results show that a reduction in total computation between 18% and 23% is achieved by the ACDI method over the PGS. In general, the results show that the ACDI method is a fast, efficient, robust and versatile method that can handle complicated unstructured grid cases with equal ease as with the structured grids

Virtual Shaping on NACA 0015 by Means of a High Momentum Coefficient Synthetic Jet

Results concerning flow control on a NACA 0015 airfoil using high power synthetic jets are presented for low incidences and for Reynolds numbers ranging from 132000 to 425000. The forcing was operated through a spanwise slit positioned near the leading edge at x/c=1.25% or at x/c=10% on the upper surface. Static pressure distribution measurements around the airfoil, wake surveys and smoke flow visualizations were performed. Pressure distributions were significantly modified around the injection location, showing an area of intense suction which increased the lift and strongly affected the drag. Flow visualizations highlighted that the intense suction was due to a virtual shaping effect caused by the formation of a recirculation bubble capable of displacing the streamlines. Low momentum deficits in the wake velocity distributions and, in certain conditions, jet-like flow was observed for the forced cases. Finally, a scaling law relating the bubble size to the forcing intensity is propose