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

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.

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

Morphometric features of the thyroid gland: a cadaveric study of Turkish people

Background: Although racial and ethnic variations in the morphology of anatomical structures are defined well, the size, shape, and weight of the thyroid gland have not previously been reported in Turkish people. This study provides data about the morphometric features of the thyroid gland, thyroid lobes, and pyramidal lobe, and highlights some anatomical variations in people from the Marmara region in Turkey. Material and methods: The material for the present study consisted of thyroid glands obtained from 75 male and 15 female adult cadavers aged between 18 and 80 years. A dissection was carried out and the thyroid glands were exposed. The glands were weighed and measured according to the various age groups of the patients. Results: A pyramidal lobe was found to be present in 57.8% of the cadavers (52/90). During midline dissection of the neck 2 males out of 90 cadavers, giving an incidence of 2.22%, did not show an isthmus. The mean thyroid weight was 26.11 ± 8.14 g. In males it was 26.93 ± 7.96 g while in females it was 21.93 ± 7.98 g. Conclusions: This is the first reported morphometric study on cadaveric thyroid glands from Turkey and it highlights individual and ethnic/racial variations. In order to perform safe and effective surgery and for the accurate diagnosis of thyroid disorders, knowledge of normal anatomy and the variations of the thyroid gland are essential. (Folia Morphol 2011; 70, 2: 103–108

Dual-Band Transmitter and Receiver with Bowtie-Antenna in 0.13 μm SiGe BiCMOS for Gas Spectroscopy at 222 - 270 GHz

This paper presents a transmitter (TX) and a receiver (RX) with bowtie-antenna and silicon lens for gas spectroscopy at 222-270 GHz, which are fabricated in IHP’s 0.13 μm SiGe BiCMOS technology. The TX and RX use two integrated local oscillators for 222 – 256 GHz and 250 – 270 GHz, which are switched for dual-band operation. Due to its directivity of about 27 dBi, the single integrated bowtie-antenna with silicon lens enables an EIRP of about 25 dBm for the TX, and therefore a considerably higher EIRP for the 2-band TX compared to previously reported systems. The double sideband noise temperature of the RX is 20,000 K (18.5 dB noise figure) as measured by the Y-factor method. Absorption spectroscopy of gaseous methanol is used as a measure for the performance of the gas spectroscopy system with TX- and RX-modules

Gene-based partial least-squares approaches for detecting rare variant associations with complex traits

Genome-wide association studies are largely based on single-nucleotide polymorphisms and rest on the common disease/common variants (single-nucleotide polymorphisms) hypothesis. However, it has been argued in the last few years and is well accepted now that rare variants are valuable for studying common diseases. Although current genome-wide association studies have successfully discovered many genetic variants that are associated with common diseases, detecting associated rare variants remains a great challenge. Here, we propose two partial least-squares approaches to aggregate the signals of many single-nucleotide polymorphisms (SNPs) within a gene to reveal possible genetic effects related to rare variants. The availability of the 1000 Genomes Project offers us the opportunity to evaluate the effectiveness of these two gene-based approaches. Compared to results from a SNP-based analysis, the proposed methods were able to identify some (rare) SNPs that were missed by the SNP-based analysis

A stereological and histopathological study of the effects of exposure of male rat testes to mercury vapor

Mercury is ubiquitous in the environment; it is an occupational pollutant and a potential toxicant. We investigated the effects of exposure of rat testes to mercury vapor (Hg-0). Twelve male rats were divided into two groups of six: the rats of the Hg-0 group were exposed to mercury (1 mg/m(3)/day) in a chamber for six weeks; the control group rats were housed under the same conditions without exposure to Hg-0. After the experimental period, the testes were removed, sections of testis were evaluated histopathologically after hematoxylin and eosin staining, and stereologically using the Cavalieri principle and optical fractionator methods. We found significant decreases in the total volume of testis, diameters of seminiferous tubules and total volume of seminiferous tubules. Significant decreases were detected in the numbers of Sertoli cells, spermatogonia, spermatocytes and spermatids of the Hg-0 group compared to the control group. In the Hg-0 exposed group, spermatogenic cells were degenerated and seminiferous tubules were atrophied.This study was supported by Ataturk University Scientific Project Fun