The paper studies optimization of shell-and-tube heat exchangers using the particle swarm optimization technique. A total cost function is formulated based on initial and annual operating costs of the heat exchangers. Six variables – shell inside diameter, tube diameter, baffle spacing, baffle cut, number of tube passes and tube layouts (triangular or square) – are considered as the design para...

Sound reflections from most finite surfaces, such as overhead reflector panels, include a component known as edge diffraction. Edge diffraction is the scattered energy required to maintain a continuous sound field despite the discontinuity in acoustical impedance presented by the scatterer. Edge diffraction can interfere with primary scattered energy to produce comb filtering at receiver locati...

The pressure conditions in insulation vacuum systems of superconducting accelerator rings or nuclear research plants is often controlled and monitored by cold-cathode gauges (hereafter CCGs). However, due to high outgassing rates of the super insulation material foils (MLI) normally used for thermal insulation, the residual gas atmosphere is dominated by high portions of hydrocarbons. If a CCG ...

Twelve patients with dextro-transposition of the great vessels (age eight months to four years) were studied by echocardiography following Mustard's procedure. Nine of them had also been studied preoperatively. Postoperatively all patients demonstrated structural echoes in the atrial cavity behind the pulmonary root. In ten, the motion pattern generally resembled that of a stenotic atrioventric...

abstract accurate water measurement and delivery are basic issues in irrigation networks management and performance. in this regard, baffle modules have been considered as appropriate means for delivering almost constant discharge within a specific range of upstream water variation. the structure is meant for low discharge delivery and could be employed in farm irrigation. however, the design c...

Pulsed Doppler evaluation of pulmonary venous flow was performed in three groups of patients who had undergone either a Mustard or Senning procedure. Group I consisted of 43 patients in sinus rhythm who had undergone the Mustard procedure 9 months or more before the Doppler examination and 16 who were evaluated immediately after surgery. Group II consisted of 12 patients in sinus rhythm who had...

From May 1963 to July 1972, 123 patients ranging in age from 20 days to 15 years, with Dtransposition of the great arteries, underwent an intraatrial baffle operation using a pericardial baffle. They previously had had a total of 121 various palliative procedures. Twenty-six children (21%) died in the early postoperative period. The operative mortality was 13% in transposition of the great arte...

In this paper, the sloshing response of liquid in a two dimensional rigid rectangular tank with rigid baffles is investigated using boundary element technique. A baffle is a supplementary structural element which supplies a kind of passive control on the effects of ground shaking. The complicated liquid domain is divided into two simple sub-domains so that the liquid velocity potential in each ...

Recently, sulfate-reducing granular sludge has been developed for application in sulfate-laden water and wastewater treatment. However, little is known about biomass stratification and its effects on the bioprocesses inside the granular bioreactor. A comprehensive investigation followed by a verification trial was therefore conducted in the present work. The investigation focused on the perform...

We report the innovation of both a partly-covered and completely-covered, variable-diameter, balloon-expandable stent that was custom-designed by NuMed, Inc for percutaneous closure of a baffle leak after total caval pulmonary connection (TCPC). A 50-year-old patient, born with tricuspid atresia, who had undergone TCPC, developed severe persistent cyanosis due to a right-to-left shunt through a...