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Optimal Cross-Sectional Shape of Gas/Air ducts

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World Journal of Engineering and Technology 2016年第3期4卷 250-255页

作者： Yongjian Gu Department of Marine Engineering United States Merchant Marine Academy Kings Point New York USA

In industrial plants, ships, and buildings, a large amount of gas and air ducts are applied for equipment connection, HVAC, medium transport, and exhaust, etc. These ducts can be designed in varied cross-sectional shapes, such as round or rectangle. The author reveals through geometric calculation of the duct cross-sectional shapes and engineering experiences that the round cross-section is an optimal shape in the duct system. The round duct has the shorter perimeter than the other cross-sectional shape ducts and the stronger structure in the same working condition. The material saving of the round duct due to the shorter perimeter is quantitatively determined. In the pater, it is shown that the round duct is economically attractive. The economic analysis for the material cost saving is illustrated by an example. For a long duct system, the material and material cost savings are significant. It is suggested that the round duct in the gas and air duct system should have priority as long as the field conditions are allowed. In the paper, the material cost saving is also converted to PW, AW, and FW used for LCC economic analysis.

关键词： Optimal ducts Cross-Sectional Shape Economic and Cost Analysis

Non-Bragg Resonance of Standing Acoustic Wave in a Cylindrical Waveguide with Sinusoidally Perturbed Walls

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Chinese Physics Letters 2005年第2期22卷 394-397页

作者：陶智勇肖雨濛王新龙 StateKeyLaboratoryofModernAcousticsandInstituteofAcoustics NanjingUniversityNanjing210093 StateKeyLaboratoryofModernAcousticsandInstituteofAcoustics NanjingUniversityNanjing210093//DepartmentofElectronicScienceandEngineeringNanjingUniversityNanjing210093

A novel type of acoustic resonance different from the well-known Braggresonance is predicted theoretically in an acoustic cylindrical waveguide with sinusoidallyperturbed hard walls. The resonance is caused by the interaction between the standing acousticwaves, i.e. transverse modes in the waveguide. It results in the frequency spectrum splitting andthe appearance of forbidden bands. For small-perturbed wall corrugation, it is found that the shiftsof resonant frequencies and the width of the forbidden gap can be as small as the wall *** appearance of the non-Bragg resonance depends highly on the wall period. When the period isgreater than 2.319 times the average cylinder radius, all the non-Bragg resonances cut off Thesmaller the wall period, the greater the transverse mode involvement.

关键词： CROSS-SECTION BAND-GAPS PROPAGATION ducts WAVEGUIDE STOPBANDS

VISCOUS FLOW BEHAVIOR IN A CURVED ANNULAR DUCT

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Journal of Hydrodynamics 1996年第2期8卷 102-110页

作者： Zhang, Benzhao Fan, Dahnine Shen, Xinrong Zhejiang Univ Hangzhou China

The perturbation solution of axial and secondary flow behavior in a curved annular duct was presented. First, a nonorthogonal cylindrical coordinate system was introduced. Second, the Navier-Stokes equations and continuity equation were established in tensorial form. The zeroth-order, first-order and second-order analytic perturbation solutions were obtained. It is found that there is a secondary flow in the annular section, and four recirculating cells in the cross section.

关键词： Approximation theory ducts Nonlinear equations Perturbation techniques Pipe flow

ON THE ORIGIN OF TURBULENT SECONDARY FLOW IN A STRAIGHT DUCT OF NON-CIRCULAR CROSS-SECTION

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Journal of Hydrodynamics 1993年第3期5卷 98-111页

作者： Zhao, Lie Wang, Famin Bian, Yungui Yu, Xin Inst of Mechanics Academia Sinica Beijing China

The origin of turbulent secondary flow in a straight duct of non-circular cross-section was discussed from a theoretical standpoint and examined from a numerical simulation of the turbulent flow in a square duct. It was reached that the driving force of such secondary flow comes from the second-order terms of the difference in gradients of normal and transverse Reynolds stresses in the axial vorticity equation. The present results obtained compare well with available experimental results for both primary and secondary flow quantities.

关键词： ducts Pipe flow Simulation

PREDICTION OF TURBULENT FLOW CHARACTERISTICS IN THE CURVED DUCT WITH A BAFFLE

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Journal of Hydrodynamics 1997年第4期9卷 19-36页

作者： Zhang, Xinyu Chen, Lihua Fan, Jianren Chen, Kefa Zhejiang Univ Hangzhou China

The changes of developing turbulent flow characteristics in curved duct after adding a baffle were studied numerically at a body-fitted coordinate. A k-Ε model was used to represent the turbulent characteristics. A curved duct with a rectangular cross-section was computed firstly. Two kinds of square ducts were studied: One was normal curved duct, the other was a duct with a baffle. The computational results show that the secondary flow in duct with a baffle is characterized by four vortices structure, compared with the duct without a baffle,the intensity of the secondary flows is reduced. This has much more significant meaning in engineering.

关键词： Computer simulation ducts Flow of fluids Hydrodynamics Mathematical models Vortex flow

Liver resection for the treatment of post-cholecystectomy biliary stricture with vascular injury

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World Journal of Gastroenterology 2015年第7期21卷 2102-2107页

作者： Marcos V Perini Paulo Herman Andre L Montagnini Jose Jukemura Fabricio F Coelho Jaime A Kruger Telesforo Bacchella Ivan Cecconello Digestive Surgery Division Depar-tment of Gastroenterology University of Sao Paulo Medical School

AIM:To report experience with liver resection in a select group of patients with postoperative biliary stricture associated with vascular ***:From a prospective database of patients treated for benign biliary strictures at our hospital,cases that underwent liver resections were *** cases were referred after one or more attempts to repair bile duct injuries following cholecystectomy(open or laparoscopic).Liver resection was indicated in patients with Strasberg E3/E4(hilar stricture)bile duct lesions associated with vascular damage(arterial and/or portal),ipsilateral liver atrophy/abscess,recurrent attacks of cholangitis,and failure of previous ***:Of 148 patients treated for benign biliary strictures,nine(6.1%)underwent liver resection;eight women and one man with a mean age of 38.6 *** patients had previously been submitted to open cholecystectomy and three to laparoscopic *** mean number of surgical procedures before definitive treatment was *** patients had Strasberg E3/E4injuries,and vascular injury was present in all *** patients underwent right hepatectomy and one underwent left lateral sectionectomy without *** time of follow up was 69.1 mo and after longterm follow up,eight patients are ***:Liver resection is a good therapeutic option for patients with complex postoperative biliary stricture and vascular injury presenting with liver atrophy/abscess in which previous hepaticojejunostomy has failed.

关键词： Abscess Atrophy Benign Bile ducts Cholecystectomy

Pedicled omental patch as a bridging procedure for iatrogenic bile duct injury

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World Journal of Gastroenterology 2017年第36期23卷 6741-6746页

作者： Jun Jie Ng Alfred Wei Chieh Kow Department of Surgery National University HospitalSingapore 119074 Singapore

Iatrogenic bile duct injuries during cholecystectomy can present as fulminant intra-abdominal sepsis which precludes immediate repair or biliary *** report the case of a 29-year-old female patient who sustained a bile duct injury after an open cholecystectomy in a neighboring *** presented to our institution 22 d after initial surgery with septic shock and multiple intra-abdominal *** retrograde cholangiography revealed a large common hepatic duct defect corresponding to a Strasberg type D bile duct *** reconstruction such as a hepaticojejunostomy cannot be performed due to the presence of dense adhesions with infected and friable *** underwent a combination of endoscopic biliary stenting and pedicled omental patch repair of the bile duct to control bile leak and sepsis as a bridging procedure to definite hepaticojejunostomy three months later.

关键词： Cholecystectomy Endoscopic retrograde cholangiopancreatography Case reports Bile ducts Abdominal abscess

Obesity and cholangiocarcinoma

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World Journal of Gastroenterology 2013年第4期19卷 457-462页

作者： Mansour A Parsi Center for Endoscopy and Pancreatobiliary Disorders Digestive Disease InstituteCleveland ClinicClevelandOH 44195United States

It is estimated that about half of the population in developed countries are either overweight or *** some developing nations obesity rates have increased to surpass those seen in Western *** rate increase in obesity has many implications as obesity has been associated with numerous negative health effects including increased risks of hypertension,diabetes,cardiovascular disease,stroke,liver disease,apnea,and some cancer *** is now considered to be one of the major public health concerns facing the ***(bile duct cancers) are malignant tumors arising from cholangiocytes inside or outside of the *** cholangiocarcinomas are relatively rare,they are highly *** low survival rate associated with cholangiocarcinoma is due to the advanced stage of the disease at the time of *** is therefore especially important in this cancer *** data suggest that the incidence of cholangiocarcinoma in the western world is on the *** rate of obesity may be one of the factors responsible for this *** whether obesity is a risk factor for cholangiocarcinoma has significant clinical and societal implications as obesity is both prevalent and *** paper seeks to provide a summary of the current knowledge linking obesity and cholangiocarcinoma,and encourage further research on this topic.

关键词： Cholangiocarcinoma Obesity Epidemiology Bile ducts Cancer

Pancreaticoduodenectomy with combined superior mesenteric vein resection without reconstruction is possible:A case report and review of the literature

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World Journal of Clinical Cases 2018年第8期6卷 214-218页

作者： Lionel Jouffret Theophile Guilbaud Olivier Turrini Jean-Robert Delpero Department of Surgical Oncology Institut PaoliC almettes

We report the case of a 56-year-old woman with pancreatic adenocarcinoma(PA) discovered during an episode of febrile jaundice. A computed tomography(CT) scan showed a mass in the head of the pancreas with circumferential infiltration of the superior mesenteric vein(SMV) and dilatation of the biliary and pancreatic ducts without metastases. The patient benefited from neoadjuvant chemotherapy(FOLFIRINOX) followed by radio-chemotherapy(45 Gy) and chemotherapy(LV5 FU2). The revaluation CT revealed SMV thrombosis without portal vein(PV) thrombosis. There was no contact of the tumor with the PV. Pancreatoduodenectomy with combined resection of the SMV was performed with no reconstruction of this venous axis after confirmation of adequate PV, splenic, and left gastric venous flow and the absence of bowel ischemia. The pathological diagnosis was p T4 N1 R0 PA. There were no bowel angina issues during the follow-up period. At 15 mo after surgery, the patient died of metastatic recurrence.

关键词： Pancreatic ducts Locally advanced No reconstruction Pancreatic adenocarcinoma Superior mesenteric vein