Thermal performance and pressure drop of different pin-fin geometries

The purpose of this study is to show the performance of hexagonal, square and cylindrical pin-fin arrays in improving heat transfer. In the present study, the thermal performance and pressure drop of the pin-fin heat exchanger are studied. The heat exchanger consists of cylindrical, hexagonal and square pin-fins. These types of pin-fins are capable of producing beneficial effects in transport enhancement and flow control. The pin-fins were arranged in an in-line manner. The relative longitudinal pitch SL/D=2 , and the relative transverse pitch were kept constant ST/D=2 . Air and water are used as working fluids in shell side and tube side, respectively. The inlet temperatures of air are between 50 and 90° C. The cold water entering the heat exchanger at the inner channel flows across the fin and flows out at the inner channel. Such pin-fins show potential for enhancing the heat transfer rate in pin-fin cross flow heat exchanger

Coronary Artery and Mitral Valve Surgery in Takayasu's Arteritis: A Case Report

Concomitant coronary artery disease and mitral valve disease are rare in Takayasu's Arteritis. Our patient had Takayasu's Arteritis diagnosed 9 years ago. She had an inferior myocardial infarction and double stent implantation 8 months ago. She was admitted to the hospital for chest pain, and 3 vessel diseases were diagnosed with significant mitral regurgitation due to anterior leaflet prolapse. In this report, we present perioperative management of our patient who underwent coronary artery bypass grafting and mitral valve replacement

Effects of open adductor tenotomy and adductor muscle botulinum toxin A injection on the hip instability in spastic type cerebral palsy

Purpose: We aimed to evaluate the clinical and radiographic outcomes of hip instability in children with spastic-type Cerebral Palsy (CP) who had undergone open Adductor Tenotomy (AT) or received Botulinum Toxin-A (BTX-A) injections to the hip adductor muscles . Materials and Methods: Maximum Hip Abduction Angles (MHAA) with the knees and hips in extension were measured preoperatively and the latest clinical findings of all patients in the AT and BTX-A groups were recorded. Reimers' Migration Percentage (RMP) was measured as the radiographic assessment in the AT group. Results: There were 30 patients (mean age: 8.3 years) in the AT Group and 25 (mean age: 5.9 years) in the BTX-A Group whose clinical and radiographic data were available. The mean follow-up period in the AT Group was 29.6 months. In the AT Group, the mean MHAA before surgery and at the last assessment were 21.20 and 37.10 respectively. In the BTX-A Group, the mean MHAA before the injection and at the latest assessment were 25.30 and 34.20 respectively. The change in the mean MHAA in the AT Group was 16.20 and 8.80 in the BTX-A Group. In the AT Group, the preoperative RMP was 28.2% and the latest RMP was 22.2%. Conclusion: AT and BTX-A injections significantly improved hip abduction angles. However, AT provided better clinical improvement and considerable radiographic correction in pediatric patients with spastic-type CP and hip instability

Experimental Research of Dynamic Instabilities in the Presence of Coiled Wire Inserts on Two-Phase Flow

The aim of this study is to experimentally investigate the effect of the coiled wire insertions on dynamic instabilities and to compare the results with the smooth tube for forced convection boiling. The experiments were conducted in a circular tube, and water was used as the working fluid. Two different pitch ratios (H/D=2.77 and 5.55) of coiled wire with circular cross-sections were utilised. The constant heat flux boundary condition was applied to the outer side of the test tube, and the constant exit restriction was used at the tube outlet. The mass flow rate changed from 110 to 20 g/s in order to obtain a detailed idea about the density wave and pressure drop oscillations, and the range of the inlet temperature was 15–35°C. The changes in pressure drop, inlet temperature, amplitude, and the period with mass flow rate are presented. For each configuration, it is seen that density wave and pressure drop oscillations occur at all inlet temperatures. Analyses show that the decrease in the mass flow rate and inlet temperature causes the amplitude and the period of the density wave and the pressure drop oscillations to decrease separately

Right Atrial Hydatid Cyst Prolapsing into the Tricuspid Valve

WOS: 000225746300026PubMed: 15745306

The reliability of estimated glomerular filtration rate in coronary artery bypass grafting

Background: In this study, we investigated the reliability of the estimated creatinine clearance and glomerular filtration rate in patients undergoing on-pump coronary artery bypass grafting

A useful cannulation strategy to facilitate re-warming during total arch replacement

"Distal-first" surgical technique with antegrade cerebral perfusion and early re-warming is a secure and comfortable method for aortic arch replacement. By using this technique, we can minimize total circulatory arrest and hypothermic periods. Cerebral morbidities can be reduced by antegrade cerebral perfusion which is achieved via both axillary cannulation and balloon-catheters. Distal organ, cerebral, and renal morbidities can be minimized by early femoral arterial perfusion and early re-warming that is re-started immediately after distal anastomosis is performed