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Numerical modeling of cavitation on spillway＇s flip bucket

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Frontiers of Structural and Civil Engineering 2016年第4期10卷 438-444页

作者： Abbas PARSAIE Sadegh DEHDAR-BEHBAHANI amir Hamzeh HAGHIABI Department of water Engineering Lorestan University Khorramabad Iran Hydro Structures Shahid Chamran University Ahvaz Iran

Numerical modeling of hydraulic phenomenon by computational fluid dynamic （CFD） approaches is one of the main parts in the high cost hydraulic structure studies. In this paper, using Flow 3D as CFD commercial tool, the cavitation phenomenon was assessed along spillway＇s flip bucket of the Balaroud dam. Performance of numerical modeling was compared to the physical model, which was constructed to this purpose. During numerical modeling, it was found that RNG turbulence model is a suitable performance for modeling the cavitation. Physical modeling shows that minimum cavitation index is about 0.85 and minimum cavitation index based on Flow 3D results is about 0.665, which was related to the flood discharge with return period of 10000 years. The main difference between numerical and physical modeling is related to the head of velocity, which is considered in physical modeling. Results of numerical simulation show that occurrence of cavitation based on cavitation index equal to 0.25 is not possible along the spillway.

关键词： cavitation Index numerical simulation spillway's flip Bucket CFD Balaroud Dam physical modeling

Photocatalytic degradation of methylene blue by nanostructured Fe/FeS powder under visible light

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International Journal of Minerals,Metallurgy and Materials 2018年第2期25卷 244-252页

作者： Hassan Esmaili amir Kotobi Saeed Sheibani Fereshteh Rashchi School of Metallurgy and Materials Engineering College of Engineering University of Tehran

The photocatalytic performance of mechano-thermally synthesized Fe/FeS nanostructures formed from micron-sized starting materials was compared with that of a thermally synthesized nanostructure with nano-sized precursors in this paper. The properties of as-synthesized materials were studied by X-ray diffraction（XRD）, transmission electron microscopy（TEM）, vibrating sample magnetometry（VSM）, diffuse reflectance spectroscopy（DRS）, and ultraviolet–visible（UV-Vis） spectroscopy. The effects of irradiation time, methylene blue（MB） concentration, catalyst dosage, and p H value upon the degradation of MB were studied. Magnetic properties of the samples showed that both as-synthesized Fe/FeS photocatalysts are magnetically recoverable, eliminating the need for conventional filtration steps. Degradation of 5 ppm of the MB solution by mechano-thermally synthesized Fe/FeS with a photocatalyst dosage of 1 kg/m^3 at pH 11 can reach 96% after 12 ks irradiation under visible light. The photocatalytic efficiency is higher in alkaline solution. The kinetics of photocatalytic degradation in both samples is controlled by a first-order reaction. However, the rate-constant value in the thermally synthesized Fe/FeS photocatalyst sample is only 1.5 times greater than that of the mechano-thermally synthesized one.

关键词： photocatalytic degradation iron sulfide nanoparticles kinetics methylene blue visible light

Seismic isolation effect of lined circular tunnels with damping treatments

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Earthquake Engineering and Engineering Vibration 2008年第3期7卷 305-319页

作者： Seyyed M. Hasheminejad amir K. Miri Acoustics Research Laboratory Department of Mechanical Engineering Iran University of Science and Technology Narmak Tehran 16844 Iran

The Havriliak-Negami model for dynamic viscoelastic material behavior and Biot＇s theory of poroelasticity are employed to develop an exact solution for three-dimensional scattering effect of harmonic plane P-SV waves from a circular cavity lined with a multilayered fluid-filled shell of infinite length containing viscoelastic damping materials and embedded within a fluid-saturated permeable surrounding soil medium. The analytical results are illustrated with numerical examples where the effects of liner/coating structural arrangement, viscoelastic material properties, liner-soil interface bonding condition, seismic excitation frequency, and angle of incidence on the induced dynamic stress concentrations are evaluated and discussed to obtain representative values of the parameters that characterize the system. It is demonstrated that incorporating viscoelastic damping materials with a low shear modulus in the constrained layer configuration is an efficient means of enhancing the overall seismic isolation performance, especially for near-normally incident seismic shear waves where the amplitudes of induced dynamic stresses may be reduced by up to one-third of those without isolation in a relatively wide frequency range. Some additional cases are considered and good agreements with solutions available in the literature are obtained.

关键词： underground tunnel permeable soil seismic wave scattering flee/constrained layer damping

Electronic behavior of native oxide films on Ti and TiN during 90-day immersion in electrolytes with different pH levels

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Rare Metals 2021年第3期40卷 582-589页

作者： amir Poursaee Golnaz Najaf-Tomaraei Marian S.Kennedy Department of Materials Science and Engineering and Glenn Department of Civil Engineering Clemson UniversityClemsonSC 29634USA Department of Materials Science and Engineering Clemson UniversityClemsonSC 29634USA

This work presents the electronic behavior of Ti and TiN thin films when exposed to electrolytes with pH levels of 2,7 and 13 for 90 *** potentio-electrochemical impedance spectroscopy tests were performed on the 100-nm Ti and TiN monolithic films,and MottSchottky analysis of these tests was used to determine the films’ semiconductive behavior and changes in the donor/acceptor *** addition,the flat-band potential of each film’s surface oxide was also *** attempt was made to control oxide formation,and therefore,these tests reflected the native surfaces of these *** the TiN films exhibited n-type semiconductivity in all electrolytes,the Ti films only showed n-type behavior in the acidic(pH=2) and neutral(pH=7) *** semiconductivity of the Ti films transitioned to p-type during exposure to the basic electrolyte(pH=13) after reaching 60 ***,there was a significant increase in the donor densities for both Ti and TiN films when immersed in the basic electrolyte relative to the acidic and neutral electrolytes.

关键词： Ti TiN Thin films Mott-Schottky analysis Semiconductivity

A comparative study between friction stir processing and friction stir vibration processing to develop magnesium surface nanocomposites

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International Journal of Minerals,Metallurgy and Materials 2020年第8期27卷 1133-1146页

作者： Behrouz Bagheri Mahmoud Abbasi Amin Abdollahzadeh amir Hossein Kokabi Department of Mining and Metallurgy Amirkabir University of TechnologyTehranIran Faculty of Engineering University of KashanRavandi Blvd.KashanIran Department of Materials Science and Engineering Sharif University of TechnologyTehranIran Institute of Materials Engineering and Advanced Processes Department of Mining and MetallurgyAmirkabir University of TechnologyTehranIran

Friction stir processing(FSP)can be used to improve surface *** this study,a modified method of FSP called friction stir vibration processing(FSVP)was applied to develop a surface composite on AZ91 magnesium *** this technique,the workpiece is vibrated normal to the processing *** results illustrated that compared with the FSP method,the FSVP caused a better homogeneous distribution of SiC particles in the *** results also showed that matrix grains of friction stir vibration processed(FSV-processed)samples((26.43±2.00)μm)were finer than those of friction stir processed(FS-processed)specimens((39.43±2.00)μm).The results indicated that the ultimate tensile strength(UTS)of FSV-processed specimens(361.82 MPa)was higher than that of FS-processed specimens(324.97 MPa).The higher plastic strain in the material during FSVP,due to workpiece vibration,resulted in higher dynamic recrystallization,and consequently,finer grains were *** elongation and formability index of the FSV-processed specimen(16.88%and 6107.52 MPa·%,respectively)were higher than those of the FS-processed sample(15.24%and 4952.54 MPa·%,respectively).Moreover,the effects of FSVP were also found to intensify as the vibration frequency increased.

关键词： friction stir processing friction stir vibration processing surface composite mechanical properties microstructure

Central serous chorioretinopathy:from glucocorticoids to light intensity

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International Journal of Ophthalmology(English edition) 2016年第2期9卷 312-314页

作者： amir Norouzpour Majid Abrishami Eye Research Center Khatam-A1-Anbia Eye HospitalMashhad University of Medical Sciences Mashhad 91959-65919 Iran Retina Research Center Khatam-A1-Anbia Eye HospitalMashhad University of Medical Sciences Mashhad 91959-65919 Iran

Central serous chorioretinopathy （CSC） is characterized by a localized accumulation of subretinal fluid and an idiopathic focal leakage from choroidal vessels. The exact pathogenesis of CSC, however, still remains obscure. In this paper, we hypothesized that CSC may result from a response of choroidal vessels to an acute increase in the environmental light intensity leading to a focal leakage from the choroidal vessels. High levels of glucocorticoids, in our proposed model, may cause persistence rather than initiation of the focal leakage, probably by suppressing the synthesis of collagen and extracellular matrix components and inhibiting fibroblastic activity.

关键词： central serous chorioretinopathy glucocorticoids light intensity temperature choroidal vessels

A hierarchical multi-purpose roller shade controller to enhance indoor comfort and energy efficiency

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Building Simulation 2023年第7期16卷 1239-1256页

作者： amir Tabadkani Morteza Haddadi Rana Abdollahi Rizi Emad Tabadkani Stantec Inc. Level 3/52 Merivale St.BrisbaneQLDAustralia Department of Energy Engineering Sharif University of TechnologyTehranIran Wellington School of Architecture Victoria University of WellingtonNew Zealand Department of Architecture Built environment and Construction engineeringPolitecnico di MilanoItaly

Building envelope is the sole interface with outdoors that can lie in the level of integrating control strategies to enhance occupant's comfort and building performance. However, in the literature, there is still a lack of multi-purpose control strategies which can balance diverse and antagonistic aspects of occupant comfort while keeping the building energy consumption under control. Therefore, this research proposed an integrated simulation-based workflow using EnergyPlus and Python-based package, OpyPlus, to adjust a roller shade for single occupied office space in a hot and arid climate. The developed system aims to improve both occupant's visual and thermal comfort considering daylight level, potential glare at occupant's field of view, view to outdoor satisfaction, and Fanger PMV method, and then, managing the HVAC system in favor of enhancing building energy efficiency. Furthermore, the controller's performance was compared to multiple fixed controls and another multi-agent control scenario from visual and thermal comfort and energy performance perspectives. The developed control system could perform effectively to provide a glare-free view and higher thermally comfortable indoor environment by 99% for the occupant across the year, while improving the heating and cooling loads. The research provides novel insights and potential future integrations for facade designers and building operators.

关键词： occupant's comfort building energy efficiency functional programming EnergyPlus Opyplus

Automatic fuzzy-DBSCAN algorithm for morphological and overlapping datasets

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Journal of Systems Engineering and Electronics 2020年第6期31卷 1245-1253页

作者： YELGHI Aref KÖSE Cemal YELGHI Asef SHAHKAR amir Department of Computer Engineering Avrasya UniversityTrabzon 61250Turkey Department of Computer Engineering Karadeniz Technical UniversityTrabzon 61080Turkey Department of Business Administration Gazi UniversityAnkara 06560Turkey Civil Engineering Department Karadeniz Technical UniversityTrabzon 61080Turkey

Clustering is one of the unsupervised learning *** is a procedure which partitions data objects into *** algorithms could not overcome the problems of morphology,overlapping and the large number of clusters at the same *** scientific communities have used the clustering algorithm from the perspective of density,which is one of the best methods in *** study proposes a density-based spatial clustering of applications with noise(DBSCAN)algorithm based on the selected high-density areas by automatic fuzzy-DBSCAN(AFD)which works with the initialization of two ***,by using fuzzy and DBSCAN features,is modeled by the selection of high-density areas and generates two parameters for merging and separating *** two generated parameters provide a state of sub-cluster rules in the Cartesian coordinate system for the *** model overcomes the problems of clustering such as morphology,overlapping,and the number of clusters in a dataset *** the experiments,all algorithms are performed on eight data sets with 30 times of *** of them are related to overlapping real datasets and the rest are morphologic and synthetic *** is demonstrated that the AFD algorithm outperforms other recently developed clustering algorithms.

关键词： clustering density-based spatial clustering of applications with noise(DBSCAN) fuzzy overlapping data mining

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Military Medical Research 2018年第2期5卷 103-110页

作者： Mostafa Allami amir Yavari amir Karimi Mehdi Masoumi Mohammadreza Soroush Elahe Faraji Janbazan Medical and Engineering Research Center(JMERC)

Background:The ankle-foot injuries are among the war-related injuries that cause many serious secondary problems for a *** nationwide study aimed to assess health-related quality of life and the ability to perform activities of daily living in veterans with ankle-foot injuries due to the Iran-Iraq ***:A total of 1079 veterans with ankle-foot injuries were enrolled in a cross-sectional study from 2014 to *** characteristics,including age,gender,marital status,disability percent,educational level,employment and additional injuries,were *** ability to perform daily activities was assessed using the Barthel activities of daily living(ADL)and Lawton instrumental activities of daily living(IADL)*** and mental health-related quality of life(HRQOL)data were measured via the SF-36 *** data were compared with those of bilateral lower limb amputees(BLLAs)and of the general Iranian *** analyses,including Pearson’s correlation coefficient,one-sample t-test and analysis of variance(ANOVA),were performed using SPSS16.0.A multiple linear regression model was used to determine the contribution of independent variables to the Physical Component Summary(PCS)and Mental Component Summary(MCS).Results:The highest and lowest scores were observed for mental health(48.93±20.69)and bodily pain(28.16±21.74),*** mean scores of veterans with ankle-foot injuries on the SF-36 were significantly lower on all eight measures than those of the general Iranian male population and of the bilateral lower limb amputees(P<0.001).The mean scores of ADLs and IADLs were 83.9±16.3 and 5.3±2.0,*** higher dependency in ADLs(P<0.001)and IADLs(P<0.001),the higher disability rate(P<0.001)and additional injury(P<0.001)were significant determinants of the ***(P<0.001)and IADL(P<0.001)limitations,additional injury(P<0.001),history of hospitalization in the year preceding the study(P=0.007)and employment(P=

关键词： Activities of daily living Instrumental activities of daily living Quality of life Ankle-foot injuries