Cfd investigation of spacer-filled channels for membrane distillation

The membrane distillation (MD) process for water desalination is affected by temperature polarization, which reduces the driving force and the efficiency of the process. To counteract this phenomenon, spacer-filled channels are used, which enhance mixing and heat transfer but also cause higher pressure drops. Therefore, in the design of MD modules, the choice of the spacer is crucial for process efficiency. In the present work, different overlapped spacers are investigated by computational fluid dynamics (CFD) and results are compared with experiments carried out with thermochromic liquid crystals (TLC). Results are reported for different flow attack angles and for Reynolds numbers (Re) ranging from ~200 to ~800. A good qualitative agreement between simulations and experiments can be observed for the areal distribution of the normalized heat transfer coefficient. Trends of the average heat transfer coefficient are reported as functions of Re for the geometries investigated, thus providing the basis for CFD-based correlations to be used in higher-scale process models

Educational Conditions of Schoolchildren of 7-8 Grades Competence Formation in Innovative Schools

The article studies methodological system of extracurricular classes, aimed at the development of senior schoolchildren’s key competences, determines educational conditions of schoolchildren’s key competences development in the course of extracurricular activities, develops the principles and ways to control schoolchildren’s independent activity; programs of training workshops for teachers and senior schoolchildren, considers some aspects of senior schoolchildren’s key competences development in the course of extracurricular classes.Educational conditions, which are necessary for competence approach to senior schoolchildren’s extracurricular activities are the following: schoolchildren’s learning and educability levels, motives, interests, professional plans determination; review of requirements for knowledge and skills of schoolchildren, learning from minimal (basic) to the advanced level of academic subject learning.We consider further didactic and methodological works of profound subject provision of the system of extracurricular classes in the framework of competence approach, including initial and major school levels as prospect trends of this problem stud

On the full scale and model scale cavitation comparisons of a Deep-V catamaran research vessel

In pushing for greener ships and more sustainable operations, designers and researchers are being challenged to increase vessel performance whilst reducing environmental impact. One topical, and a somewhat challenging aspect of this pursuit, is the reduction in Underwater Radiated Noise (URN). There are several European Collaborative Research Projects currently underway that aim to outline a framework for noise standards, amongst these projects is the Seventh Framework Project (FP7) “Suppression of Underwater Noise Induced by Cavitation” (SONIC) that has been tasked with concentrating on the URN from propeller cavitation; the main contributor to underwater noise generation. As one of the participants of the SONIC project the Newcastle University was involved in the full-scale trials and model-scale propeller testing campaign. The full-scale trial conducted on board Newcastle University’s catamaran research vessel R/V The Princess Royal involved cavitation observations though the dedicated observation windows above each propeller, Propeller Excited Vibration measurements as well as the off-board URN measurements. The model scale tests were made in The Emerson Cavitation Tunnel using a 1:3.5 scale dummy model of the starboard side demi-hull of the vessel. These tests tried to emulate, as best as possible, the full-scale trials in terms of measurement locations and viewing angles

Single coronary artery incidence in 215,140 patients undergoing coronary angiography

Background: The aim of our study is to determine the incidence of single coronary artery (SCA). SCA is a rarely seen coronary anomaly in which the right coronary artery and the left main coronary artery arise from single aortic sinus. Although SCA has a benign course in most cases and its clinical significance is unknown, in some autopsy studies it was shown to be related to sudden cardiac death. Materials and methods: SCA patients detected among 215,140 coronary angiographies (CAG) performed between 1998 and 2013 in SANKO Hospital were included in our study. The classification of CAG was made according to the two different classifications defined by Smith and Lipton and colleagues. Results: A total number of 215,140 patients who underwent routine CAG were included in the study, and SCA was detected in 67 (0.031%) patients. There were 6 (9%) type R-I, 23 (34%) type R-II, 10 (15%) type R-III, 16 (24%) type L-I and 12 (18%) type L-II patients according to the angiographic classification. Conclusions: SCA is rarely seen during routine cardiac catheterisation and its incidence is 0.014–0.066% in angiographic series. In our study, the incidence was shown to be similar to the previous studies.

Direct Evidence of a Slow‐Slip Transient Modulating the Spatiotemporal and Frequency‐Magnitude Earthquake Distribution: Insights From the Armutlu Peninsula, Northwestern Turkey

Earthquakes and slow‐slip events interact, however, detailed studies investigating their interplay are still limited. We generate the highest resolution microseismicity catalog to date for the northern Armutlu Peninsula in a ∼1‐year period to perform a detailed seismicity distribution analysis and correlate the results with a local, geodetically observed slow‐slip transient within the same period. Seismicity shows a transition of cluster‐type behavior from swarm‐like to burst‐like, accompanied by an increasing relative proportion of clustered (non‐Poissonian) relative to background (Poissonian) seismicity and gradually decreasing b‐value as the geodetically observed slow‐slip transient ends. The observed slow‐slip transient decay correlates with gradually increasing effective‐stress‐drop values. The observed correlation between the b‐value and geodetic transient highlights the influence of aseismic deformation on seismic deformation and the impact of slow‐slip transients on local seismic hazard

Base Station Antenna with Enhanced Cross Polarization Discrimination Performance by Using Horizontal Meandered Dipole and Vertical Parasitic Elements

This study is related with the design of a ± 45° dual polarized base station antenna with improved cross-polarization discrimination (XPD) values. Parasitic elements are added to antenna design formed by orthogonal two compact meandered dipole above ground plane. The antenna designed with CST Microwave Studio program has VSWR ≤ 2 within 1.71-2.69 GHz frequency band, which covers GSM 1800/3G/LTE bands. The antenna has minimum of 0 dBi gain in the beamwidth of 120° ( 60°) at azimuth plane (ϕ = 0°) along the band, and XPD values being minimum of 2 dB at 1.71-2.4 GHz for  60° without parasitic elements are improved to 10 dB with parasitic elements. This design initially had two horizontal straight monopoles on the ground plane perpendicular to each other. Afterwards, antenna with microstrip balun feed applied but the XPD values were not appropriate to expected results. Because of that, by using image theory, vertical parasitic elements were added to get appropriate XPD values. Later, meandered structure used to make antenna smaller. Finally, according to base station applications, antenna frequencies optimized to 1.71 GHz and 2.69 GHz. The designed and optimized antenna produced and measured in laboratory environment. Return losses for port 1 and port 2 are measured above the 10 dB and isolation between the port 1 and port 2 are measured above the 20 dB. In addition, the maximum gain values are measured between 3 dB and 7 dB in 1.71 GHz and 2.69 GHz frequency band.  Finally, XPD values are measured more than 10 dB in bandwidth

A new energy saving twin rudder system - Gate Rudder

Rudder and propeller of a ship share almost similar long service history. The rudder is usually placed behind the propeller to make use of the strong slipstream flow of the propeller. By changing the direction of the slipstream flow the rudder functions as a remarkably effective control surface to maneuver the ship. While this is the fact the rudder also has several disadvantages including: (a) increased ship resistance as an appendage to the hull; (b) modifications to the stern arrangement to accommodate the rudder that enforces restriction not only to the propeller aperture but also to the engine room arrangement; (c) a non-uniform flow imposed in the propeller plane that can easily increase the vibration and noise originated not only from the propeller but also from the combination of the propeller with the rudder; (d) cavitation erosion on the rudder which can be annoying for high speed vessels In order to eliminate the above disadvantages as well as saving further energy, a new concept of twin rudder system is invented one of the Authors and called “Gate Rudder” in which each of the asymmetric rudders is located aside the propeller to exploit the benefits of an accelerating duct device. The main objective of this paper is to give the background for the gate rudder development and present methodology for powering performance of a ship with the gate rudder using the Emerson Cavitation Tunnel facility. The analysis include model tests to measure the local forces on the stern part of a model hull and gate rudder system in the cavitation tunnel as well as the prediction of the gate rudder induced velocities using computational methods. The papers further presents a flow chart for the fine powering performance prediction technology and cost effectiveness analysis of vessels using the gate rudder system

Coronary arterial anomalies in a large group of patients undergoing coronary angiography in southeast Turkey

Background: The prevalence of coronary artery anomalies (CAA) are reportedbetween 0.6–1.3% in the literature. CAA are usually asymptomatic incidental findings, but they may deteriorate coronary circulation, cause symptoms andlead to sudden cardiac death; especially in young athletes. Since interventionalprocedures are increasing rapidly for treatment of coronary artery disease (CAD) inthe modern era, comprehensive understanding of CAA is becoming progressively critical element in dealing with CAD.Materials and methods: We reviewed the database of the Cardiac Catheterisation Laboratory of Sani Konukoglu University Hospital in Gaziantep, Turkey. All patientswho were subjected to coronary angiography from 1998 to 2006 were included.Results: Among 53,655 coronary angiographies performed, CAA were foundin 653 patients (incidence of 1.21%); 590 (90.3%) patients had anomalies oforigin and distribution and 63 (11.7%) had coronary fistulae. Separate origins ofleft anterior descending (LAD) and left circumflex (LCX) coronary artery from theleft sinus of Valsalva was the most common anomaly (64.1%). Coronary arteriesbranching from anomalous aortic origin was the second most common anomaly(16.5%). Right coronary artery (RCA) originating from left sinus of Valsalva or leftmain coronary artery (LMCA) was observed in 55 (8.4%) patients, LCX arising fromRCA or right sinus of Valsalva (RSV) was seen in 52 (7.9%) patients and LMCA orLAD originating from RSV was seen in 14 (0.2%) patients. There were 16 (2.45%) patients with single coronary artery and 1 (0.15%) patient with LMCA originating from pulmonary artery.Conclusions: The incidence and the pattern of CAA in our patient population were similar with previous studies. Angiographic recognition of these vessels is importantbecause of their clinical significance and importance in patients undergoing coronary angioplasty or cardiac surgery