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Transactions of Nonferrous Metals Society of China 2014年第8期24卷 2482-2488页

作者： Hamed KHOSRAVI Hamed BAKHSHI erfan SALAHINEJAD Faculty of Materials Science and Engineering K.N. Toosi University of Technology

The effects of compocasting process parameters on some structural and tensile characteristics of the A356-10% SiCp (volume fraction) composites were studied. Semisolid stirring was carried out at temperatures of 590, 600 and 610 °C with stirring speeds of 200, 400 and 600 r/min for 10, 20 and 30 min. The distribution of the SiC particles within the matrix, porosity content and tensile properties of the obtained samples were examined. The structural evaluations show that by increasing the stirring time and decreasing the stirring temperature, the uniformity in the particle distribution is improved;however, by increasing the stirring speed the homogeneity firstly increases and then declines. It is also found that by increasing all of the processing parameters, the porosity content is enhanced. From the tensile characteristics viewpoint, the optimum values of the speed, temperature and time are found to be 400 r/min, 590 °C and 30 min, respectively. The contribution of the reinforcement distribution uniformity prevails over that of the porosity level to the tensile properties.

关键词： A356-SiC_p composite semisolid stirring compocasting porosity reinforcement distribution tensile properties

Entrainment of *** and Listeria monocytogenes from sediment in irrigation canal

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International Journal of Sediment Research 2022年第6期37卷 701-714页

作者： Kun Qi erfan Ghasemi Tousi Jennifer Guohong Duan Patricia Marie Gundy Kelly Rae Bright Charles Peter Gerba Department of Civil & Architectural Engineering and Mechanics The University of Arizona Department of Environmental Science The University of Arizona Water & Energy Sustainable Technology (WEST) Center

E. coli and Listeria monocytogenes(or L. monocytogenes) are bacteria affecting fresh produce that is harmful for health of humans and animals. If these bacteria are present in surface waterbody(e.g.,irrigation canals), they will impair irrigation water quality and threaten produce safety. This paper studied the resuspension of E. coli and Listeria from bed sediment into irrigation water through several sets of laboratory experiments in an open channel flume. We studied three types of sediments using several flow rates in different velocities and shear stress. Bacteria’s concentration in water increases with the bed shear stress. Two empirical relations were derived to correlate the concentration of E. coli and L. monocytogenes with the dimensionless bed shear stress. The experimental data favorably verified the relationships for sandy loam, loamy sand, and loam. The results showed that both bacteria could entrain from sand more efficiently compared to other sediments(i.e., sandy loam or loam). These relationships can be applied to water quality models for simulating E. coli and L. monocytogenes transport in irrigation canals for better managing irrigation water quality.

关键词： Bacteria E. coli L. monocytogenes Sediment transport Irrigation water Sediment model

Dual Band MIMO Antenna Composed of Two Low Profile Unbalanced Fed Inverted L Antennas for Wireless Communications

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Wireless Engineering and Technology 2014年第3期5卷 54-61页

作者： erfan Rohadi Mitsuo Taguchi Graduate School of Engineering Nagasaki University Nagasaki Japan The State Polytechnic of Malang Malang Indonesia The State Polytechnic of Malang Malang Indonesia

A low profile dual-band multiple-input-multiple-output (MIMO) antenna system is proposed. The proposed MIMO antenna consists of two low profile unbalanced fed inverted L antennas with parasitic elements to resonate at 2.45 GHz and 5 GHz. The structure is uncomplicated by locating two ultra low profile inverted L antennas on the finite conducting plane. The proposed MIMO antenna is numerically and experimentally analyzed. When the size of conducting plane is 55 mm by 55 mm and the height of antenna is 9 mm, the directive gain of 4.11 dBi and the S11 bandwidth of 5.71% are achieved for lower frequency of 2.45 GHz. At the upper frequency of 5 GHz, the directive gain of 8.22 dBi and the S11 bandwidth of 6% are obtained. The proposed antenna has good diversity gain, shown by the correlation coefficient becomes less than 0.005 at the frequency of 2.45 GHz and 5 GHz band when the distance between inverted L elements is 41 mm. A good agreement between calculated and measured results is obtained. The results show that the weak mutual coupling of the proposed antenna and this feature enables it to cover the required bandwidths for WLAN operation at the 2.4 GHz band and 5 GHz band.

关键词： Dual Band MIMO Inverted L Antenna ILA Low Profile Antenna Parasitic Element Correlation Coefficients ISM WCS

Effects of ultrasonic waves on carbon dioxide solubility in brine at different pressures and temperatures

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Petroleum Science 2017年第3期14卷 597-604页

作者： Hossein Hamidi erfan Mohammadian Amin Sharifi Haddad Roozbeh Rafati Amin Azdarpour Panteha Ghahri Adi Putra Pradana Bastian Andoni Chingis Akhmetov School of Engineering King’s College University of Aberdeen Faculty of Chemical Engineering University Technology MARA Department of Petroleum Engineering Marvdasht BranchIslamic Azad University

The adverse impacts of CO2 emission on the global warming highlight the importance of carbon capture and storage technology and geological storage of CO2 under solubility trapping mechanisms. Enhancing the solubility of CO2 in formation water has always been the focus of research in the area of CO2 sequestration. Ultrasound techniques are one of the environmentally friendly methods that use high-intensity acoustic waves to improve gas solubility in liquids. Ultrasonic waves can alter the properties of different phases that lead to chemical reactions and provide a means to increase the solubility of CO2 in connate water. In this study, we investigated the effects of ultrasound on the solubility of CO2 in connate water under different conditions of pressure, temperature, and salinity. The results showed that the solubility of CO2 was improved with increasing pressure under ultrasonic ***, the solubility of CO2 was inversely proportional to the increase in brine salinity and temperature. Therefore,it was concluded that the solubility of CO2 might be enhanced in the presence of ultrasound.

关键词： Carbon dioxide CO2 sequestration Ultrasound High-frequency waves Solubility

Neuromorphic metasurface

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Photonics Research 2020年第1期8卷 46-50页

作者： ZHICHENG WU MING ZHOU erfan KHORAM BOYUAN LIU ZONGFU YU Department of Electrical and Computer Engineering University of WisconsinMadisonWisconsin 53706USA

Metasurfaces have been used to realize optical functions such as focusing and beam *** use subwavelength nanostructures to control the local amplitude and phase of *** we show that such control could also enable a new function of artificial neural *** demonstrate that metasurfaces can directly recognize objects by focusing light from an object to different spatial locations that correspond to the class of the object.

关键词： surfaces enable surface

Evaluation of direct intramural injection to the bladder wall as a method for developing orthotopic tumor models

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Animal Models and Experimental Medicine 2022年第6期5卷 575-581页

作者： Masoud Bitaraf Samad Muhammadnejad Ashkan Azimzadeh Saman Behboodi Tanourlouee erfan Amini Masoumeh Majidi Zolbin Abdol-Mohammad Kajbafzadeh Pediatric Urology and Regenerative Medicine Research Center GeneCell and Tissue Research InstituteTehran University of Medical SciencesTehranIran Gene Therapy Research Center Digestive Diseases Research InstituteTehran University of Medical SciencesTehranIran Uro-oncology Research Center Tehran University of Medical SciencesTehranIran

Background:Bladder cancer poses a great burden on society and its high rate of recurrence and treatment failure necessitates use of appropriate animal models to study its pathogenesis and test novel *** models are superior to other types since they provide a normal *** methods are described for developing bladder cancer models inside the animal’s *** intramural injection is one of these methods and is widely ***,its efficacy in model development has not yet been *** aimed to evaluate the efficacy and success rate of the direct intramural injection method of developing an orthotopic model for the study of bladder ***:Tumor cell lines were prepared in four *** of 200×10^(3) cells were injected through a 27 gauge needle into the ventral wall of the bladders of 4male and 4 female BALB/c mice following a midline 1 cm laparotomy *** addition,1 million cells from each microtube were injected into the flanks of control *** prevent infection and alleviate pain,5 mg/kg enrofloxacin and 2.5 mg/kg flunixin meglumine,respectively,were injected ***:Tumors formed in all mice,resulting in 100% take rate and zero post-operation *** time was≤15 min per *** two mice,tumors were found in the peritoneal space as ***:Direct intramural injection is a rapid,reliable,and reproducible method for developing orthotopic models of bladder *** can be done on both male and female mice and only requires readily available surgical ***,needle track can result in cell spillage and peritoneal tumors.

关键词： animal model bladder cancer bladder wall injection model evaluation orthotopic model

Radar Signal Recognition by CWD Picture Features

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International Journal of Communications, Network and System Sciences 2012年第4期5卷 238-242页

作者： erfan Tahbaz Tavakoli Abolfazl Falahati DCCS Laboratory Department of Electrical Engineering Iran University of Science and Technology Tehran Iran

In this paper a system for automatic recognition of radar waveform is introduced. This technique is used in many spectrum management, surveillance, and cognitive radio and radar applications. For instance the transmitted radar signal is coded into six codes based on pulse compression waveform such as linear frequency modulation (LFM), Frank code, P1, P2, P3 and P4 codes, the latter four are poly phase codes. The classification system is based on drawing Choi Willliams Distribution (CWD) picture and extracting features from it. In this study, various new types of features are extracted from CWD picture and then a pattern recognition method is used to recognize the spectrum. In fact, signals from CWD picture are defined using biometric techniques. We also employ false reject rate (FRR) and false accept rate (FAR) which are two types of fault measurement criteria that are deploy in biometric papers. Fairly good results are obtained for recognition of Signal to Noise Ratio (-11 dB).

关键词： Pulse Compression Radar Spectrum Management Signal Recognition

Numerical Prediction of Laminar-to-Turbulent Transition Around the Prolate Spheroid

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Journal of Marine Science and Application 2021年第1期20卷 46-54页

作者： erfan Kadivar Ebrahim Kadivar Seyed Morteza Javadpour Department of Physics Shiraz University of TechnologyShiraz 71555-313Iran Institute of Ship Technology Ocean Engineering and Transport SystemsUniversity of Duisburg-Essen47057 DuisburgGermany Department of Mechanical Engineering University of GonabadGonabadIran

In this work,the laminar-to-turbulent transition phenomenon around the two-and three-dimensional ellipsoid at different Reynolds numbers is numerically *** the present paper,Reynolds Averaged Navier Stokes(RANS)equations with the Spalart-Allmaras,SST k-ω,and SST-Trans models are used for numerical *** possibility of laminar-toturbulent boundary layer transition is summarized in phase diagrams in terms of skin friction coefficient and Reynolds *** numerical results show that SST-Trans method can detect different aspects of flow such as adverse pressure gradient and laminar-to-turbulent transition *** numerical results indicate that the laminar-to-turbulent transition location on the 6:1 prolate spheroid is in a good agreement with the experimental data at high Reynolds numbers.

关键词： Laminar-to-turbulent transition Shear stress transport turbulence model Skin fraction Three-dimensional ellipsoid

Nanophotonic media for artificial neural inference

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Photonics Research 2019年第8期7卷 823-827页

作者： erfan KHORAM ANG CHEN DIANJING LIU LEI YING QIQI WANG MING YUAN ZONGFU YU Department of Electrical and Computer Engineering University of Wisconsin MadisonMadisonWisconsin53706USA Department of Aeronautics and Astronautics Massachusetts Institute of TechnologyCambridgeMassachusetts02139USA Department of Statistics Columbia UniversityNew YorkNew York10027USA

We show optical waves passing through a nanophotonic medium can perform artificial neural *** information is encoded in the wavefront of an input light. The medium transforms the wavefront to realize sophisticated computing tasks such as image recognition. At the output, the optical energy is concentrated in well-defined locations, which, for example, can be interpreted as the identity of the object in the *** computing media can be as small as tens of wavelengths and offer ultra-high computing density. They exploit subwavelength scatterers to realize complex input/output mapping beyond the capabilities of traditional nanophotonic devices.

关键词： image simulation Nanophotonic media

Grayscale image statistics of COVID-19 patient CT scans characterize lung condition with machine and deep learning

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Chronic Diseases and Translational Medicine 2022年第3期8卷 191-206页

作者： Sara Ghashghaei David A.Wood erfan Sadatshojaei Mansooreh Jalilpoor Medical School Shiraz University of Medical SciencesShirazIran Deparment of Research DWA Energy LimitedLincolnLN59JPUK Department of Chemical Engineering Shiraz UniversityShiraz71345Iran

Background:Grayscale image attributes of computed tomography(CT)of pulmonary scans contain valuable information relating to patients with respiratory *** attributes are used to evaluate the severity of lung conditions of patients confirmed to be with and without ***:Five hundred thirteen CT images relating to 57 patients(49 with COVID-19;8 free of COVID-19)were collected at Namazi Medical Centre(Shiraz,Iran)in 2020 and *** visual scores(VS:0,1,2,3,or 4)are clinically assigned to these images with the score increasing with the severity of COVID-19-related lung *** deep learning and machine learning techniques(DL/ML)are used to distinguish the VS class based on 12 grayscale image ***:The convolutional neural network achieves 96.49%VS accuracy(18 errors from 513 images)successfully distinguishing VS Classes 0 and 1,outperforming clinicians’visual *** algorithmic score(AS),involving just five grayscale image attributes,is developed independently of clinicians’assessments(99.81%AS accuracy;1 error from 513 images).Conclusion:Grayscale CT image attributes can be successfully used to distinguish the severity of COVID-19 lung *** AS technique developed provides a suitable basis for an automated system using ML/DL methods and 12 image attributes.

关键词： computed tomography analysis confusion-matrix analysis COVID-19 lung feature recognition grayscale image attributes visual versus algorithmic classification