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Laminar Periodic Flow and Heat Transfer in a rectangular Channel with Tri-angular wavy Baffles

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Journal of Thermal Science 2012年第3期21卷 250-261页

作者： Smith Eiamsa-ard Pongjet Promvonge Department of Mechanical Engineering Faculty of EngineeringMahanakorn University of Technology Department of Mechanical Engineering Faculty of EngineeringKing Mongkut's Institute of Technology Ladkrabang

This paper presents a numerical analysis of laminar periodic flow and heat transfer in a rectangular constant temperature-surfaced channel with triangular wavy baffles (TwBs).The TwBs were mounted on the opposite walls of the rectangular channel with inline *** TwBs are placed on the upper and lower walls with attack angle 45?.The numerical is performed with three dif-ferent baffle height ratios (Br=b/H=0.05 0.3) at constant pitch ratio (Pr) of 1.0 for the range 100 ≤ re ≤ *** computational results are shown in the topology of flow and heat *** is found that the heat transfer in the channel with the TwB is more effective than that without *** in-crease in the blockage ratio,Br leads to a considerable increase in the Nusselt number and friction *** results indicate that at low Br,a fluid flow is significantly disturbed resulting in inefficient heat *** Br increases,both heat transfer rate in terms of Nusselt number and pressure drop in terms of friction factor *** the range examined,the maximum Nu/Nu0 of 7.3 and f/f0 of 126 are both found with the use of the baffles with Br=0.30 at re=*** addition,the flow structure and temperature field in the channel with TwBs are also reported.

关键词： Heat transfer Laminar periodic flow Channel flow Triangular wavy baffle

Analysis of Turbulent Heat Transfer and Fluid Flow in Channels with Various ribbed Internal Surfaces

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Journal of Thermal Science 2011年第3期20卷 260-267页

作者： Smith Eiamsa-ard wayo Changcharoen Department of Mechanical Engineering Faculty of Engineering Mahanakorn University of Technology Bangkok 10530 Thailand

This paper presents results of a numerical investigation of heat transfer and flow pattern characteristics of a channel with repeated ribs on one broad wall. Numerical computations are performed for seven ribs placed on the bottom wall of a channel for reynolds numbers ranging from 10,000 to 30,000. The newly modified ribs (the ones with convex pointing upstream/downstream rib, wedge pointing upstream/downstream rib, concave pointing upstream/downstream rib and also concave-concave rib as well as convex-concave rib), are proposed for simulation with prospect to reduce flow separation and extend reattachment area compared to the unmodified square rib. The numerical results are reported in forms of flow structure, temperature field, turbulent kinetic energy, Nusselt number, friction factor and thermal enhancement factor. The results indicate the rib with concave-concave surfaces efficiently suppresses flow separation bubble in the corner of the rib and induces large recirculation zone over those of the others, hence giving the highest Nusselt number and friction factor. On the other hand, the one with convex-concave surface provides the lowest friction factor with moderate Nusselt number. Due to the prominent effect of its low friction factor, the rib with convex-concave surface offers the highest thermal enhancement factor of 1.19.

关键词： rib Turbulent flow Heat transfer reattachment zone Flow separation

Numerical prediction of vortex flow and thermal separation in a subsonic vortex tube

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第8期7卷 1406-1415页

作者： SMITH Eiamsa-ard PONGJET Promvonge Department of Mechanical Engineering Faculty of Engineering Mahanakorn University of Technology Bangkok 10530 Thailand Department of Mechanical Engineering Faculty of Engineering King Mongkut's Institute of Technology Ladkrabang Bangkok 10520 Thailand

This work was aimed at gaining understanding of the physical behaviours of the flow and temperature separation process in a vortex tube. To investigate the cold mass fraction’s effect on the temperature separation, the numerical calculation was carried out using an algebraic reynolds stress model (ASM) and the standard k-ε model. The modelling of turbulence of com-pressible, complex flows used in the simulation is discussed. Emphasis is given to the derivation of the ASM for 2D axisymmet-rical flows, particularly to the model constants in the algebraic reynolds stress equations. The TEFESS code, based on a staggered Finite Volume approach with the standard k-ε model and first-order numerical schemes, was used to carry out all the computations. The predicted results for strongly swirling turbulent compressible flow in a vortex tube suggested that the use of the ASM leads to better agreement between the numerical results and experimental data, while the k-ε model cannot capture the stabilizing effect of the swirl.

关键词： Vortex tube Cold mass fraction Swirl fiow Temperature separation Flow field

Heat transfer characteristics in micro-fin tube equipped with double twisted tapes: Effect of twisted tape and micro-fin tube arrangements

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Journal of Hydrodynamics 2013年第2期25卷 205-214页

作者： EIAMSA-ard S. wONGCHArEE K. Department of Mechanical Engineering Faculty of Engineering Mahanakorn University of Technology Department of Chemical Engineering Faculty of Engineering Mahanakorn University of Technology

An experimental study was carried out to investigate the influence of double twisted-tape inserts （DTs） in micro-fin tubes （MFs） on heat transfer, friction factor and thermal performance factor characteristics of the compound devices in the following configurations：（1） twisted tapes acted in the same direction （for co-swirl） while MF and twisted tapes acted in the same （parallel） direction （MF-CoDTs：P）, （2） twisted tapes acted in the same direction （for co-swirl） while micro-fin tube and twisted tapes acted in opposite directions （MF-CoDTs：O） and （3） twisted tapes acted in opposite directions for counter swirl （MF-CDTs）. The MF alone and the MF equipped with a single twisted tape in parallel/opposite arrangement were also considered for comparison. The experiments were conducted for the flows with the reynolds numbers between 5 650 and 17 000, under uniform heat flux condition. The experimental results indicate that MF-CDTs induce stronger swirl/turbulence flow, resulting in higher heat transfer rate, friction factor and thermal performance factor than other combined devices. The thermal performance factors associated with the use of MF-CDTs were found to be higher than those associated with the uses of MF-CoDTs：P, MF-CoDTs：O and MF alone up to 9.3%, 6.5% and 56.4%, respectively. The empirical correlations developed using the present experimental data for the Nusselt number, friction factor and thermal performance factor are also reported.

关键词： micro-fin tube (MF) double twisted-tapes (DTs) co-swirl counter-swirl heat transfer enhancement

Lead zirconate(PbZrO_(3))embedded in natural rubber as electroactive elastomer composites

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Journal of Innovative Optical Health Sciences 2014年第6期7卷 56-62页

作者： Anuvat Sirivat Karat Petcharoen Yanee Pornchaisiriarun Chaleomwut Phansa-ard Nuchnapa Tangboriboon The Petroleum and Petrochemical College Chulalongkorn University Bangkok 10330Thailand The Materials Engineering Department and Center for Advanced Studies in Industrial Technology Faculty of Engineering Kasetsart UniversityBangkok 10900Thailand

Perovskite lead zirconate(PbZrOz)was synthesized in an orthorhombic form at a temperature below the Curie temperature,*** orthorhombic form is a noncentrosymmetric structure which is capable of spontaneous *** transform infrared(FTIr)spectra and X-ray diffraction(XrD)patterns confirm the siuccessful synthesis of the lead zirconate;and scanning electron microscopy(SEM)micrographs indicate that PbZrO_(3) particles are moderately dispersed in the natural rubber(Nr)*** an electrical field,the particles merely act as a ferroelectric fller,which can absorb and store additional *** an electrical field,particle induced dipole motents are generated,leading to interparticle interaction and a sub-stantial increase in the storage *** a small amount of lead ziroonate part iculates present in the natural rubber matrix,at a volume fraction of 0.007306,the electrical conductivity increases dramatically by nearly two orders of magnitude at the electrical frequency of 500 kHz.

关键词： Natural rubber perovskite lead zirconate actuator sensors smart engineering devices

Per rectal portal scintigraphy as a useful tool for predicting esophageal variceal bleeding in cirrhotic patients

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world Journal of Gastroenterology 2007年第5期13卷 791-795页

作者： Taned Chitapanarux Ong-ard Praisontarangkul Satawat Thongsawat Pises Pisespongsa Apinya Leerapun Division of Gastroenterology Department of Internal Medicine Faculty of Medicine Chiang Mai University Chiang Mai 50200 Thailand

AIM: To investigate potential roles of per rectal portal scintigraphy in diagnosis of esophageal varices and predicting the risk of ***: Fifteen normal subjects and fifty cirrhotic patients with endoscopically confirmed esophageal varices were included. Patients were categorized into bleeder and non-bleeder groups according to history of variceal bleeding. All had completed per rectal portal scintigraphy using 99mTechnetium pertechnetate. The shunt index was calculated from the ratio of 99mTechnetium pertechnetate in the heart and the liver. Data were analyzed using Student’s t-test and receiver operating ***: Cirrhotic patients showed a higher shunt index than normal subjects (63.80 ± 25.21 vs 13.54 ± 6.46, P with variceal bleeding showed a higher shunt index than those without bleeding (78.45 ± 9.40 vs 49.35 ± 27.72, P r 20% indicated the presence of varices and that of over 60% indicated the risk of variceal ***: In cirrhotic patients, per rectal portal scintigraphy is a clinically useful test for identifying esophageal varices and risk of variceal bleeding.

关键词： Portal scintigraphy Portal hypertension Cirrhosis Esophageal varices Bleeding

winery by‑products as a feed source with functional properties:dose–response effect of grape pomace,grape seed meal,and grape seed extract on rumen microbial community and their fermentation activity in rUSITEC

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Journal of Animal Science and Biotechnology 2023年第6期14卷 2439-2453页

作者： ratchaneewan Khiaosa‑ard Mubarik Mahmood Elsayed Mickdam Catia Pacifico Julia Meixner Laura‑Sophie Traintinger Institute of Animal Nutrition and Functional Plant Compounds Department for Farm Animals and Veterinary Public HealthUniversity of Veterinary Medicine ViennaVeterinaerplatz 11210 ViennaAustria. Animal Nutrition Section Department of Animal SciencesSub Campus JhangUniversity of Veterinary and Animal Sciences12 Km Chiniot RoadJhang 35200LahorePakistan. Nutrition and Clinical Nutrition Department Faculty of Veterinary MedicineSouth Valley UniversityQena 83523Egypt. Present address:Biome Diagnostics GmbH ViennaAustria.

Background Grape and winery by-products have nutritional values for cattle and also contain functional compounds like phenols,which not only bind to protein but can also directly affect microbiota and their function in the *** characterized the nutritional and functional effects of grape seed meal and grape pomace as well as an effective dosage of grape phenols on ruminal microbiota and fermentation characteristics using a rumen simulation *** Six diets(each n=8)were compared including a control diet(CON,no by-product),a positive control diet(EXT,CON+3.7%grape seed extract on a dry matter(DM)basis),two diets with grape seed meal at 5%(GS-low)and 10%(GS-high),and two diets with grape pomace:at 10%(GP-low)and 20%(GP-high),on a DM *** inclusion of the by-product supplied total phenols at 3.4%,0.7%,1.4%,1.3%,and 2.7%of diet DM for EXT,GS-low,GS-high,GP-low,and GP-high,*** were tested in four experimental *** treatments decreased ammonia concentrations and the disappearances of DM and OM(Pred to *** and GP-high lowered butyrate and odd-and branch-chain short-chain fatty acids while increased acetate compared to CON(Preatments did not affect methane *** decreased the abundance of many bacterial genera including those belonging to the core ***-high and EXT consistently decreased Olsenella and Anaerotipes while increased ruminobacter *** The data suggest that the inclusion of winery by-products or grape seed extract could be an option for reducing excessive ammonia *** to grape phenols at a high dosage in an extract form can alter the rumen microbial ***,however,does not necessarily alter the effect of grape phenols on the microbial community function compared to feeding high levels of winery *** suggests the dominant role of dosage over the form or source of the grape phenols in affecting ruminal microbial *** conclusion,

关键词： Functional feed Grape pomace Grape seed Protein degradation rumen microbiota

插入双面有三角形翅片的金属带对热交换管中流动和传热特性的影响(英文)

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Chinese Journal of Chemical Engineering 2011年第3期19卷 410-423页

作者： Smith Eiamsa-ard Pongjet Promvonge Department of Mechanical Engineering Faculty of Engineering Mahanakorn University of Technology Faculty of Engineering King Mongkut's Institute of Technology Ladkrabang

The convective heat transfer and friction behaviors of turbulent tube flow through a straight tape with double-sided delta wings(T-w)have been studied *** the current work,the T-w formed on the tape was used as vortex generators for enhancing the heat transfer coefficient by breakdown of thermal boundary layer and by mixing of fluid flow in *** T-w characteristics are(1)T-w with forward/backward-wing arrangement,(2)T-w with alternate axis(T-wA),(3)three wing-width ratios and(4)wing-pitch *** experimental result reveals that for using the T-w,the increases in the mean Nusselt number(Nu)and friction factor are,respectively,up to 165%and 14.8 times of the plain tube and the maximum thermal performance factor is *** is also obvious that the T-w with forward-wing gives higher heat transfer rate than one with backward-wing around 7%. The present investigation also shows that the heat transfer rate and friction factor obtained from the T-wA is higher than that from the *** addition,the flow pattern and temperature fields in the T-w tube with both backward and forward wings were also examined numerically.

关键词： fluid flow heat transfer tape with centre-wing wing alternate axis vortex

Establishment and characterization of a cholangiocarcinoma cell line (rMCCA-1) from a Thai patient

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world Journal of Gastroenterology 2006年第40期12卷 6500-6506页

作者： Panthip rattanasinganchan Kawin Leelawat Sa-ard Treepongkaruna Chintana Tocharoentanaphol Somboon Subwongchareon Tuangporn Suthiphongchai rutaiwan Tohtong Department of Biochemistry Faculty of Science Mahidol University Bangkok 10400 Thailand Department of Biochemistry Faculty of Science Mahidol University Bangkok 10400 ThailandDepartment of Surgery Rajavithi Hospital Bangkok 10400 ThailandCancer Cytogenetic Unit Chulabhorn Cancer Center Chulabhorn Research Institute Patumthani 12000 Thailand Department of Surgery Rajavithi Hospital Bangkok 10400 Thailand Cancer Cytogenetic Unit Chulabhorn Cancer Center Chulabhorn Research Institute Patumthani 12000 Thailand

AIM: To establish and characterize a new cell line derived from peripheral cholangiocarcinoma of a Thai ***: The peripheral cholangiocarcinoma specimen surgically obtained from the patient was aseptically processed by washing and mincing before culturing in Ham’s F12 medium containing 10% fetal bovine serum. After 3 mo, when the cell line has become homogeneous and stabilized, several features were investigated, including growth characteristics, immunofluorescence staining for cytokeratins, expression of tumor markers, chromosomal analysis by G-banding and multicolour fluorescence in situ hybridization (mFISH), in vitro migration and invasion characteristics. rESULTS: The rMCCA-1 cell line has been established. These cells proliferated as a monolayer with a population doubling time of 48 h. Immunofluorescence staining showed positive staining for human cytokeratin 7 and 19 verifying the biliary epithelial origin. rMCCA-1 secreted carbohydrate antigen 19-9 (CA19-9), but insignificant levels of carcinoembryonic antigen (CEA) and α-fetoprotein (AFP). Chromosome analysis identified aneuploidy karyotypes with a modal chromosome number of 59. rMCCA-1 exhibited a low level of in vitro invasiveness, but a high degree of motility. The cell line exhibited a significant number of chromosomal aberrations as shown by mFISH and G-banding ***: A new cell line derived from peripheral cholangiocarcinoma of a Thai patient has been established. This cell line shows a low level of in vitro invasiveness, but a high degree of motility. It will serve as a valuable tool for further studies on tumor biology, molecular pathogenesis, metastatic mechanism and response to therapeutic drugs of cholangiocarcinoma.

关键词： Cholangiocarcinoma Cell line Establishment mFISH Invasion Migration