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Intrahepatic cholestasis without jaundice

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Hepatobiliary & Pancreatic Diseases International 2009年第1期8卷 103-105页

作者： thomas namdar Andreas Raffel Stefan Andreas Topp Jan Schulte am Esch Günther Fürst Wolfram Trudo Knoefel Claus Ferdinand Eisenberger Department of General Visceral and Pediatric Surgery Heinrich-Heine University Institute of Diagnostic Radiology Heinrich-Heine University

BACKGROUND:Cholangiocarcinoma(CC),the most common biliary tract malignancy,is frequently seen in advanced unresectable stages and is typically localized *** diagnosis is unusual because of nonspecific *** jaundice is usually the first sign of tumor. METHOD:We present a patient with a CC(Klatskin tumor) with a complete biliary drainage by an aberrant bile duct without jaundice. RESULTS:A 67-year-old woman presented with persisting elevation of liver *** tests showed a Klatskin tumor typeⅡ.A curative right hepatic trisegmentectomy was performed after liver volume augmentation by preoperative vein embolization. CONCLUSIONS:A direct drainage of the right posterior bile duct into the common bile duct as an aberrant hepatic duct is a rare variation and is present in less than 5%of the *** case of persistently perturbed liver function tests,an aberrant bile duct can cover up severe intrahepatic cholestasis and even obscure the diagnosis of a Klatskin *** to now it has not been described in the literature.

关键词： Klatskin tumor hyperbilirubinemia cholangiocarcinoma

A robust principal component analysis-based approach for detection of a stator inter-turn fault in induction motors

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Protection and Control of Modern Power Systems 2022年第1期7卷 714-737页

作者： Ali namdar School of Electrical and Computer Engineering Shiraz UniversityShirazIran

Health condition monitoring of induction motors is important because of their vital role and wide us in a variety of industries.A stator inter-turn fault(SITF)is considered to be the most common electrical failure according to statisti-cal *** this paper,an algorithm for the detection of an SITF is *** is based on one of the blind source separation techniques called principal component analysis(PCA).The proposed algorithm uses PCA to discriminate between the faulty components of motor current signatures and motor voltage signatures from other *** standard deviation of one of the decomposed vectors is used as a statistical SITF *** proposed criterion is robust to non-fault conditions including voltage quality problems and large mechanical load changes as well as harmonic contaminants in the voltage *** addition,with a straightforward and low computational burden in the fault detection process,the proposed method is computationally *** evaluate the performance of the proposed method,large numbers of practical and simulation scenarios are considered,and the results confrm the good performance,high degree of accuracy,and good convergence speed of the proposed method.

关键词： Induction motors(IMs) Stator inter-turn fault(SITF) Voltage quality problem Principal component analysis(PCA)

Characterization and Prediction of Nonlinear Stress-Strain Relation of Geostructures for Seismic Monitoring

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Structural Durability & Health Monitoring 2021年第2期15卷 167-182页

作者： Abdoullah namdar Faculty of Architecture and Civil Engineering Huaiyin Institute of TechnologyHuai’anChina Environmental Quality Atmospheric Science and Climate Change Research GroupTon Duc ThangUniversityHo Chi Minh CityVietnam Faculty of Environment and Labour Safety Ton Duc Thang UniversityHo Chi Minh CityVietnam

The nonlinearity of the strain energy at an interval period of applying seismic load on the geostructures makes it difficult for a seismic designer to makes appropriate engineering judgments *** nonlinear stress and strain analysis of an embankment is needed to evaluate by using a combination of suitable *** this study,a large-scale geostructure was seismically simulated and analyzed using the nonlinear finite element method(NFEM),and linear regression method which is a soft computing technique(SC)was applied for evaluating the results of NFEM,and it supports engineering judgment because the design of the geostructures is usually considered to be an inaccurate process owing to high nonlinearity of the large-scale geostructures seismic response and such nonlinearity may induce the complexity for decision making in geostructures seismic *** occurrence of nonlinear stress and nonlinear strain probability distribution can be observed and density of stress and strain are predicted by using the *** results of both the simulation from the NFEM and the linear regression method confirm the nonlinearity of strain energy and stress behavior have a close value of R2 and root-mean-square error(RMSE).The linear regression and histogram simulation shows the accuracy of NFEM *** outcome of this study guides to improve engineering judgment quality for seismic analysis of an embankment through validating results of NFEM by employing appropriate soft computing techniques.

关键词： NFEM geostructure stress strain linear regression model histogram

Influence of ECAP on the fatigue behavior of age-hardenable 2xxx aluminum alloy

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International Journal of Minerals,Metallurgy and Materials 2015年第3期22卷 285-291页

作者： M.namdar S.A.Jenabali Jahromi Department of Materials Science and Engineering School of Engineering Shiraz University

The fatigue behavior under load control and the mechanical properties of commercial 2011 aluminum as an age-hardenable A1 al- loy was studied. To estimate the effects of the equal channel angular pressing （ECAP） process, solution heat treatments, and aging on the fa- tigue life, tests were conducted at four different stages： furnace cooling; furnace cooling plus one ECAP pass; solid solution heat treatment, quenching, one ECAP pass plus aging at peak age level; and the T6 condition. Only one pass was possible at room temperature because of the high strength of the material. The fracture surface morphology and microstructure after fatigue were evaluated by scanning electron mi- croscopy （SEM）. The experimental results revealed that the optimum fatigue life under load control, the tensile strength, and the Vickers hardness of the material were interdependent. The optimum fatigue life under load control was achieved by increasing the tensile strength and hardness of the material.

关键词： aluminum alloys equal channel angular pressing precipitation mechanical properties fatigue life

Behavior Analysis of Biomimetic Soft Bending Actuators in Free Motion and Contact

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Journal of Bionic Engineering 2023年第3期20卷 967-981页

作者： Mohammad Hadi namdar Ghalati Sepideh Akbari Hamed Ghafarirad Mohammad Zareinejad Department of Mechanical Engineering Amirkabir University of TechnologyTehran***Iran New Technologies Research Center(NTRC) Amirkabir University of TechnologyTehran***Iran

Bioinspired Soft Bending Actuators (SBA) are increasingly being used in rehabilitation, assistant robots, and grippers. Despite many investigations on free motion modeling, understanding how these actuators interact with the environment requires more detailed research. It is caused by high compliance and nonlinearity of bioinspired soft material, which leads to serious challenges in contact conditions. In this paper, a continuous deformation analysis is presented to describe the free motion nonlinear behavior of the actuator. Based on the achieved result, this study proposes static modeling of SBA affected by a concentrated external force. For this purpose, the finite rigid element method is utilized, which is based on discretizing the actuator into smaller parts and assuming these parts as rigid serial links connected by nonlinear torsional springs. To verify the proposed model, two kinds of forces are considered to be acting on the actuator, i.e. following force and constant direction force. In addition, the effect of gravity on the actuator configuration is also investigated. The validity of the model has been demonstrated through experiments in free motion, contact conditions and the presence of gravity. It generally shows that the prediction error of robot configuration is lower than 7.5%.

关键词： Biomimetic soft bending actuator Static modeling Contact Force constraints Rigid finite element

Spatially resolved investigation of flame particle interaction in a two dimensional model packed bed

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Particuology 2024年第2期85卷 167-185页

作者： Mohammadhassan Khodsiani Reza namdar Fathollah Varnik Frank Beyrau Benoit Fond Institute of Fluid Dynamics and Thermodynamics Universitaetsplatz 2Magdeburg39106Saxony-AnhaltGermany Interdisciplinary Centre for Advanced Materials Simulation(ICAMS) Ruhr-University BochumBochum44801Germany ONERA The French Aerospace Lab Department of AerodynamicsAeroelasticity and Acoustics(DAAA)Paris-Saclay UniversityMeudon92190France

This study investigates the interaction between a premixed methane-air flame and particles inside a model packed *** opacity of the spherical packed beds to visible light poses a major barrier to the implementation of highly resolved optical diagnostics,so that no detailed experimental data were so far available for the validation of numerical ***,a two-dimensional cylindrical packed bed design is set up,which enables direct line-of-sight optical measurements without loss of spatial reso-lution over the fluid region between the *** this study,the case of cold metallic cylindrical particles(T=377 K)relevant to start-up of a reactor is investigated using internal particle cooling,which also allows cylinder specific heat transfer rate measurements by differential temperature measurements on the coolant *** two dimensional assumption is first verified by measuring the inflow ve-locity and cylinder temperature profile along the *** imaging is then per-formed using a telecentric lens to observe the position and geometry of the two-dimensional flame front with respect to the surrounding cylinders without loss of ***,the cylinder-specific flame to cylinder heat transfer rates and cylinder surface temperature are *** the flame is closely surrounded by the three cooled cylinders,intense heat transfer is observed in this region corresponding to 25±2.5%of the flame thermal *** were stabilised at different positions depending on inflow velocity and equivalence ratio,and a direct correlation between flame to cylinder stand-off distance and the heat transfer rate normalised to the flame thermal power was found for both top and side ***,sidewall quenching distances to the curved cylinder surfaces were evaluated,and seem to be influenced by the presence of a warm recirculation zone behind the *** investigation provides fully resolved flame front position and heat tra

关键词： Packed beds Flame-particle interaction Optical diagnostics Sidewall quenching

Application of biocementation technique using Bacillus sphaericus for stabilization of soil surface and dust storm control

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Journal of Arid Land 2022年第5期14卷 537-549页

作者： Davood namdar-KHOJASTEH Masoud BAZGIR Seyed Abdollah HASHEMI BABAHEIDARI Akwasi B ASUMADU-SAKYI Department of Soil Science Faculty of AgricultureShahed UniversityTehran ***Iran Department of Soil and Water Engineering Faculty of AgricultureIlam UniversityIlam ***Iran Department of Plant Protection Faculty of AgricultureShahed UniversityTehran ***Iran International Laboratory for Air Quality and Health School of ChemistryPhysics and Mechanical EngineeringQueensland University of TechnologyBrisbaneQueensland 4000Australia

Dust emission and wind erosion are widespread phenomena in arid and semi-arid regions,which have far-reaching harmful effects to the *** study aimed to use microbial induced carbonate precipitation(MICP)method with Bacillus sphaericus to reduce soil losses that occur in a dust-producing area due to wind erosion in the Ilam Province,*** samples at the 0-30 cm depth were used and sterilized in an autoclave for 2 h at 121℃ and 103 *** 3 kg soils were weighed and poured in the 35 cm×35 cm×3 cm *** treatments included two levels of ***(0.0 and 0.5 OD),three levels of suspension volume(123,264,and 369 mL),two levels of urea-chloride cementation solution(0.0 and 0.5 M),and two levels of bacterial spray(once and twice spray).After 28 d,soil properties such as soil mass loss,penetration resistance,and aggregate stability were *** results showed a low soil mass loss(1 g)in F_(14)formulation(twice bacterial spray+264 mL suspension volume+without cementation solution)and a high soil mass loss(246 g)in F_(5) formulation(without bacteria+264 mL suspension volume+0.5 M cementation solution).The highest(42.55%)and the lowest(19.47%)aggregate stabilities were observed in F_(16)and F_(7)formulations,respectively,and the highest penetration resistance(3.328 kg/cm^(2))was observed in F_(18) *** to the final results,we recommended the formulation with twice bacterial spray,0.5 M cementation solution,and 269 mL suspension volume as the best combination for soil surface ***,this method is environmentally friendly because it has no adverse effects on soil,water,and plants,thus,it would be an efficient approach to stabilize soil surface.

关键词： soil stabilization microbial cementation calcium carbonate bacteria penetration resistance

Numerical study of convective heat transfer in static arrangements of particles with arbitrary shapes:A monolithic hybrid lattice Boltzmann-finite difference-phase field solver

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Particuology 2024年第2期85卷 186-197页

作者： Reza namdar Mohammadhassan Khodsiani Hesameddin Safari Tanya Neeraj Seyed Ali Hosseini Frank Beyrau Benoit Fond Dominique Thevenin Fathollah Varnik Interdisciplinary Centre for Advanced Materials Simulation(ICAMS) Ruhr-University BochumBochum44801Germany Laboratory of Technical Thermodynamics University of Magdeburg"Otto von Guericke"Magdeburg39106Germany Laboratory of Fluid Dynamics and Technical Flows University of Magdeburg"Otto von Guericke"MagdeburgD-39106Germany Department of Mechanical and Process Engineering ETH ZurichZurich8092Switzerland ONERA The French Aerospace Lab Department of AerodynamicsAeroelasticity and Acoustics(DAAA)Paris-Saclay UniversityMeudon92190France

A compressible lattice Boltzmann-finite difference method is extended by the phase-field approach into a monolithic scheme to study fluid flow and heat transfer through regular arrangements of solid bodies of circular,elliptical and irregular *** advantage of using the phase-field method is demon-strated both in its simplicity of accounting for flow and thermal boundary conditions at solid surfaces with irregular shapes and in the capability of generating such complex-shaped *** an array of discs,numerical results for the overall solid-to-gas heat transfer rate are validated via experiments on flow through arrays of hot *** thus validated compressible LB-FD-PF hybrid scheme is used to study the dependence of heat transfer on flow and thermal boundary conditions(Reynolds number,temperature difference between the hot solid bodies and the inlet gas),porosity as well as on the shape of solid *** are rationalized in terms of the residence time of the gas close to the solid body and downstream variations of gas velocity and *** for further applications of the proposed methodology are also discussed.

关键词： Lattice Boltzmann method Finite difference scheme Convective heat transfer Diffuse interface Thermal compressible flow

Optimization of ultrasonic-assisted extraction of phenolic compounds from pomegranate and orange peels and their antioxidant activity in a functional drink

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Food Bioscience 2022年第5期49卷 1156-1165页

作者： Afshin Selahvarzi Yousef Ramezan Mohammad Reza Sanjabi Bahareh namdar Marjan Akbarmivehie Hossein Mirsaeedghazi Fatemeh Azarikia Department of Food Science and Technology Faculty of PharmacyTehran Medical SciencesIslamic Azad UniversityTehranIran Nutrition&Food Sciences Research Center Tehran Medical SciencesIslamic Azad UniversityTehranIran Iranian Research Organization for Science and Technology(IROST) TehranIran Department of Food Science and Technology Shahr-e-Qods BranchIslamic Azad UniversityTehranIran Food Biopolymer Research Group Food Science and Technology DepartmentDamghan BranchIslamic Azad UniversityDamghanIran Department of Food Technology College of AburaihanUniversity of TehranTehranIran

This study aimed to optimize the ultrasound extraction conditions of phenolic compounds from pomegranate (PPE) and orange peels (OPE) as agricultural wastes and use the optimized extracts to enrich a functional drink. The statistical analysis results demonstrated that the quadratic model used had high R2 (>0.89) and good predictability of experimented results. In optimizing the extraction of PPE and OPE, the effect of three factors of extraction time (X1:10-40 min), temperature (X2: 40-70 ◦C), and solid to a solvent ratio (X3: 1:20-1:40 g/mL) on two responses of total phenol content (TPC) and antioxidant activity were investigated. The highest TPC (2.70 and 1.86 mg GAE/g) and antioxidant activity (72.11 and 54.27%) of PPE and OPE were obtained in the X1: 40 min, X2: 70 ◦C, and X3: 1:40 g/mL. No significant difference was observed between the predicted and experimental values. The results of drink tests indicated that adding PPE and OPE and increasing their levels from 10% to 15% v/v in the drinks significantly enhanced the samples’ bioactive compounds content and antioxidant activity (p < 0.05). The content of vitamin C (212.37 mg/100 mL) and flavonoids (83.44 mg QE/100 mL) in the drink containing 15% OPE was higher than in other samples, while the sample containing 15% PPE had the highest TPC (158.88 mg GAE/100 mL). There was a positive relationship between the level of extracts and the antioxidant activity of the drinks. During 60-days of cold storage, the content of bioactive compounds and antioxidant activity of drink samples gradually decreased (p < 0.05).

关键词： Antioxidant Orange Pomegranate Ultrasound Optimization Functional drink