• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.5
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• pp.579-587
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• 1999

The flow distribution characteristics in a complex duct system have been investigated in this paper by three means, namely experimental measurement, numerical simulation and the Extended T-method analysis. While the exit flow rates predicted by the three-dimensional CFD calculation and those given by the experiment show a close agreement, the results from the one-dimensional Extended T-method are found to differ from the experiment by -22.2% to 26.3% for the various exits. These discrepancies may be attributed to the underlying limitation concerning the fitting loss coefficients, which assume that the flow in front of the fittings is fully developed. It is proposed that, in order to analyse the three-dimensional flow distributions in a complex duct system by one-dimensional analysis such as the Extended T-method, further Improvements to the fitting loss coefficients should be made.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.181-184
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• 2002

CFD calculations are carried out to investigate the turbulent flow characteristics inside the duct of marine waterjet propulsors. The Reynolds-averaged Wavier-Stokes equations are solved using a finite-volume method. Standard $k-{\varepsilon}$ model and realizable $k-{\varepsilon}$ model are evaluated with an existing experimental data. Multi-block grid topology is adopted to describe the details of complex duct geometry. The present numerical methods are applied to the preliminary duct design of new waterjet propulsor system. Four different influx conditions are simulated to find out pressure and velocity distribution inside the intake duct. Attention is also paid upon the possible flow separation inside the waterjet duct. It is found that CFD tools can be used for the initial evaluation of inflow condition into the impeller of waterjet propulsor system.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.4
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• pp.533-542
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• 1999

In this study the flow characteristics of developing turbulent pulsating flows in a square-sec-tional 180。 curved duct are investigated experimentally. The experimental study of air flow in a square-sectional curved duct is carried out to measure axial velocity distribution secondary flow velocity profiles and wall shear stress distributions by using a Laser Doppler Velocimetry system with the data acquisition and processing system of Rotating Machinery Resolver (RMR) and PHASE software at the entrance region of the duct which is divided into 7 sections from the inlet(${{\o}}=0_{\circ}$) to the outlet (${{\o}}=180_{\circ}$) in $30_{\circ}$ intervals. The results obtained from the study are summarized as follows: (1) The time-averaged critical Dean number of turbulent pulsating flow(De ta, cr) is greater than $75{\omega}+$ It is understood that the critical Dean number and the critical Reynolds number are related to the dimensionless angular frequency in a curved duct. (2) Axial velocity profiles of turbulent pulsating flows are of an annular type similar to those of turbulent stead flows. (3) Secondary flows of trubulent pulsating flows are strong and complex at the entrance region. As velocity amplitudes(A1) become larger secondary flows become stronger. (4) Wall shear stress distributions of turbulent pulsating flows in a square-sectional $180_{\circ}$ curved duct are exposed variously in the outer wall and are stabilized in the inner wall without regard to the phase angle.

• Fire Science and Engineering
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• v.29 no.4
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• pp.39-48
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• 2015

This research was done to develop a duct-dedicated intelligent fire detection system to prevent fires and minimize fire damage of the industrial duct having a high fire risk. To understand the fire hazards of the ducts, the analysis was centered on the Daegu Textile Industrial Complex, where industrial ducts are used frequently. With this in the background, dedicated fire detectors and fire alarm control panel, which can prevent fires and to minimize fire damages to the ducts, were designed and produced, after which the performance was confirmed. As a result of performance experiments, it was shown that a duct-dedicated intelligent fire detection system had excellent adaptability and temperature accuracy. Through real-time temperature monitoring of the inside of the ducts, it was confirmed that duct fires could be efficiently extinguished by stepwise control of linkage facilities according to the setting temperature.

• Journal of computational fluids engineering
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• v.2 no.2
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• pp.44-50
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• 1997

Accurate simulation of jet plume exhausting into the open space as well as onto the opposing wall is of interest both numerically and physically; the latter, from a system designer's point of view. In the current work, Navier-Stokes computation is undertaken to capture the flow pattern of a supersonic jet impinging onto a rectangular duct which deflects the vertical jet horizontally. Of particular interest are the flow structure in the jet exhaust area, pressure pattern and the magnitude of pressure force at the bottom wall. Usefulness of present characteristic boundary condition applied at the exiting plane of the duct is demonstrated by capturing such complex flow structures for different lengths of the deflection duct.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.9
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• pp.4363-4365
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• 2016

Background: The complex anatomy of the pancreaticobiliary duct was crucial in management of pancreatic and biliary tract disease. Materials and Methods: Fresh specimens of pancreas, common bile duct (CBD), and duodenum were obtained en bloc from autopsies of 160 patients. Results: Ninety-three male and 67 female patients were included. The length of the pancreas ranged from 9.8-20 cm (mean, 16.20 +/- 1.70 cm). The intrapancreatic portion of the CBD showed patterns of three types: most common (85.30%) was type A, in which the anterior surface of the common bile duct was totally covered, while its posterior surface was partially covered, by the pancreatic parenchyma. On dissection of the accessory duct of Santorini, the accessory duct was traceable to the duodenal wall in 67.6%. The anatomy of the Wirsung-choledochus confluence was grouped into five different types. The common channel was found in 75.60% and its length varied from just a common junction (so-called "V-type" anatomy) to 15 mm (Y-type-b). Separate papillae (so-called "II-type") were found in 15.3% of specimens. Conclusions: Several important points regarding the anatomy of the pancreaticobiliary junction and pancreatic ductal system were illustrated in this study.

• Proceedings of the Korean Nutrition Society Conference
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• 1995.05c
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• pp.21-21
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• 1995

Absorption of fat-soluble vi tamin, retinol occurs mainly in the proximal part of small intestine. But its intestinal transport mechanism isn't yet clear. The aim of the present study was to investigate on the mechanism of absorption of retinol by determining a concentration-dependent kinetic of retinol absorption in rats. The study was carried out by applying in vivo technique in which vitamin solution was infused to intestinal lumen and at the same time thoracic duct and choledochus duct were canulated to collect samples. The investigations showed that retinol is absorbed in the small intestine by a saturable, carrier-mediated transport system, i.e. wi thout signi ficant differences between the proximal and distal halves of the small intestine. The transport of retinol taken up by the enterocytes occured via different mechanisms: while the main vitamin A transport via the thoracic duct was saturated by limiting transport factors such as retinol-CRBP-II-complex formation and retinol esterification with increasing substrate concentrations, the transport of retinol metabolite product via the portal vein was proportional to the substrate concentration.ration.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.10 no.2
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• pp.78-97
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• 2000

Designing the industrial ventilation system is the complex and time-consuming job. It could generate some errors in the design calculations if one uses the hand-calculator or the spreadsheet program. To overcome these difficulties, VSDS(Ventilation System Design Software) had been developed a few years ago. But, it had the difficulty in designing a complex system having many branches because the user can not see the layout of the system on the screen. Another difficulty is that VSDS had been based on the assumption of the standard air condition. VSDS has thus been improved to overcome the shortcomings of the old version of VSDS.

• Anatomy and Cell Biology
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• v.57 no.1
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• pp.31-44
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• 2024

The exocrine part of the pancreas has a duct system called the pancreatic ductal system (PDS). Its mechanism of development is complex, and any reorganization during early embryogenesis can give rise to anatomical variants. The aim of this study is to collect, classify, and analyze published evidence on the importance of anatomical variants of the PDS, addressing gaps in our understanding of such variations. The MEDLINE, Web of Science, Embase, and Google Scholar databases were searched to identify publications relevant to this review. R studio with meta-package was used for data extraction, risk of bias estimation, and statistical analysis. A total of 64 studies out of 1,778 proved suitable for this review and metanalysis. The meta-analysis computed the prevalence of normal variants of the PDS (92% of 10,514 subjects). Type 3 variants and "descending" subtypes of the main pancreatic duct (MPD) predominated in the pooled samples. The mean lengths of the MPD and accessory pancreatic duct (APD) were 16.53 cm and 3.36 cm, respectively. The mean diameters of the MPD at the head and the APD were 3.43 mm and 1.69 mm, respectively. The APD was present in only 41% of samples, and the long type predominated. The pancreatic ductal anatomy is highly variable, and the incorrect identification of variants may be challenging for surgeons during ductal anastomosis with gut, failure to which may often cause ductal obstruction or pseudocysts formation.

• Nuclear Engineering and Technology
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• v.37 no.4
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• pp.391-394
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• 2005

N-(3-bromo-2,4,6-trimethylacetanilide)iminodiacetic acid (BrTIDA) was synthesized using nitrilotriacetic anhydride prepared in situ, and lyophilized vials were prepared which contained 20 mg of BrTIDA and 0.4 mg of $SnCl_2$. To evaluate the clinical efficacy of the in-house prepared lyophilized kit, a technetium-99m complex of BrTIDA was prepared; its in vivo pharmacokinetic behavior was evaluated via animal studies to assess the hepatocytic function and the functional status of the cystic duct and the gallbladder. Serial static image scans of rabbits and the biodistribution in mice injected with $^{99m}Tc-BrTIDA$ revealed that none of the tissues except for the hepatobiliary system showed radioactivity concentrations, and a rapid clearance from the organs was observed. In conclusion, a lyophilized kit and its prepared $^{99m}Tc-BrTIDA$ can be applied as a hepatobiliary imaging agent for the evaluation of the functional status of the hepatocytes and the patency of the biliary duct.