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Development of a radiographic method for measuring the discrete spectrum of the electron beam from a plasma focus device

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Plasma Science and Technology 2017年第7期19卷 26-33页

作者： Neda SHAMSIAN babak SHIRANI BIDABADI Hosein PIRJAMADI Department of Nuclear Engineering Faculty of Advanced Sciences and Technologies University of Isfahan

An indirect method is proposed for measuring the relative energy spectrum of the pulsed electron beam of a plasma focus device. The Bremsstrahlung x-ray, generated by the collision of electrons against the anode surface, was measured behind lead filters with various thicknesses using a radiographic film system. A matrix equation was considered in order to explain the relation between the x-ray dose and the spectral amplitudes of the electron beam. The electron spectrum of the device was measured at 0.6 mbar argon and 22 kV charging voltage, in four discrete energy intervals extending up to 500 keV. The results of the experiments show that most of the electrons are emitted in the 125-375 keV energy range and the spectral amplitude becomes negligible beyond 375 keV.

关键词： magnetized plasma plasma focus plasma diagnostics electron beam energyspectrum x-ray dosimetry

Experimental investigation of typical surface treatment effect on velocity fluctuations in turbulent flow around an airfoil

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Chinese Journal of Aeronautics 2023年第10期36卷 112-123页

作者： babak ELHAMI Mojtaba DEHGHAN MANSHADI Ali Akbar DEHGHAN Faculty of Mechanical Engineering Malek Ashtar University of TechnologyIsfahan 177415875Iran Mechanical Engineering Faculty Yazd UniversityYazd ***Iran

Noise reduction of different airfoils is important because these sections are used in wind turbines,propellers,and aircraft *** methods are used for passive noise reduction of *** of these methods is the use of surface *** this research,the effect of the typical surface treatment element(finlets)on the vortex structure at different frequencies in the turbulent flow created on the NACA2412 section is *** this purpose,one-dimensional hot wire probe is *** used surface treatment in this research has a special geometry and the distance between two consecutive finlets is 6 mm(S=6 mm).This study shows that this surface treatment element can be used for noise reduction in high *** result of this research is the suggestion of the most suitable position to install this special surface treatment element to reduce vortex energy in all frequency *** installation location is determined based on a dimensionless parameter(X_(aft)/h).

关键词： Finlet spacing Passive noise reduction Sound Pressure Level(SPL) Surface treatment(finlets) Velocity power spectral density

Bacteriophages and their applications in the diagnosis and treatment of hepatitis B virus infection

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World Journal of Gastroenterology 2014年第33期20卷 11671-11683页

作者： babak Bakhshinejad Majid Sadeghizadeh Department of Genetics Faculty of Biological Sciences Tarbiat Modares University Tehran 14115-111 Iran

Hepatitis B virus(HBV) infection is a major global health challenge leading to serious disorders such as cirrhosis and hepatocellular carcinoma. Currently, there exist various diagnostic and therapeutic approaches for HBV infection. However, prevalence and hazardous effects of chronic viral infection heighten the need to develop novel methodologies for the detection and treatment of this infection. Bacteriophages, viruses that specifically infect bacterial cells, with a long-established tradition in molecular biology and biotechnology have recently been introduced as novel tools for the prevention, diagnosis and treatment of HBV infection. Bacteriophages, due to tremendous genetic flexibility, represent potential to undergo a huge variety of surface modifications. This property has been the rationale behind introduction of phage display concept. This powerful approach, together with combinatorial chemistry, has shaped the concept of phage display libraries with diverse applications for the detection and therapy of HBV infection. This review aims to offer an insightful overview of the potential of bacteriophages in the development of helpful prophylactic(vaccine design), diagnostic and therapeutic strategies for HBV infection thereby providing new perspec-tives to the growing field of bacteriophage researches directing towards HBV infection.

关键词： Bacteriophage Hepatitis B virus Phage dis-play Phage library Biopanning Diagnosis Treatment Vaccine development

Effect of graphene functionalizing on the performance of NiMo/graphene in HDS and HDN reactions

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Petroleum Science 2019年第5期16卷 1185-1195页

作者： babak Behnejad Majid Abdouss Ahmad Tavasoli Department of Chemistry Amirkabir University of TechnologyTehranIran School of Chemistry College of ScienceUniversity of TehranTehranIran

In this research,to remove sulfur and nitrogen compounds from heavy naphtha,various nanocatalysts were prepared through supporting NiMo over nanoporous graphene and evaluated in hydrodesulfurization and hydrodenitrogenation *** nanoporous graphene was initially functionalized in order to facilitate the metal being loaded on *** different methods were used to functionalize the nanoporous *** NiMo/nanoporous graphene nanocatalysts were characterized by field emission scanning electron microscopy,Fourier transform infrared spectroscopy,X-ray diffraction,inductively coupled plasma optical emission spectrometry,temperature-programmed reduction,nitrogen adsorption-desorption isotherms and transmission electron microscopy *** performance was evaluated in terms of conversions of sulfur,mercaptans(R-SH)and nitrogen *** was found that the functionalized nanoporous graphene support could significantly enhance the catalytic performance in comparison with the industrial NiMo/alumina *** the functionalized graphene supports,amine-functionalized graphene exhibited the best *** using NiMo supported over amine-functionalized graphene,the conversions of total sulfur and R-SH reached 97.8%and 98.1%,respectively.

关键词： Hydrodesulfurization(HDS) Hydrotreating(HDT) Nanocatalyst Catalyst support Graphene functionalization NiMo/nanoporous graphene

An analytical solution for spherical fluid flow modeling in porous media with non-uniform initial pressure considering the supercharging effect

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Petroleum 2021年第3期7卷 303-313页

作者： Ali Nabizadeh Mohammad Sharifi babak Aminshahidi Institute of GeoEnergy Engineering School of EnergyGeoscienceInfrastructure and SocietyHeriot-Watt UniversityEdinburghUK Department of Petroleum Engineering Amirkabir University of Technology(Tehran Polytechnic)P.O.Box:15875-4413TehranIran

The diffusivity equation is a partial differential equation(PDE)which can be used for fluid flow modeling in porous *** reservoir parameters from pressure data(i.e.,pressure transient analysis)is one of the most important steps in the process of field *** initial evaluation can be used to make decisions about future *** Formation Testing(WFT)is one of the most popular techniques for parameter estimation and has received significant attention in recent *** main problem plaguing WFT is a phenomenon known as the“supercharging effect,”which essentially refers to mud invasion,and this,in turn,alters pressure distribution across the *** this study,an analytical solution for fluid flow modeling in spherical coordinates with non-uniform initial pressure is *** new procedure takes into account the effect of mud invasion,or,in other words,the supercharging *** accuracy of this derivation was validated using previous semianalytical solutions(the Laplace method)in addition to field *** type curves and dimensionless parameters,which can be used for pressure transient analysis,are also *** procedure is applied to the WFT data that was obtained from an oil field in the south of Iran,and an excellent agreement(less than 10%error)was *** addition,there is considerable uncertainty regarding the radius of investigation for spherical *** is important as this parameter greatly affects the applicability of *** analytical derivation of this study was used to determine a reasonable value for this parameter as well.

关键词： Porous media Analytical solution Supercharging effect Welltesting Spherical Darcy's flow

Comparison of performance of Ni-Mo/γ-alumina catalyst in HDS and HDN reactions of main distillate fractions

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Petroleum Science 2019年第3期16卷 645-656页

作者： babak Behnejad Majid Abdouss Ahmad Tavasoli Department of Chemistry Amirkabir University of Technology Tehran Iran School of Chemistry College of Science University of Tehran Tehran Iran

A bimetallic nickel-molybdenum catalyst supported on γ-alumina was synthesized by the two-step incipient wetness impregnation *** activity of the prepared Ni-Mo/γ-alumina catalyst was evaluated in a down flow fixed-bed *** this way,hydrodesulfurization(HDS)and hydrodenitrogenation(HDN)reactions of the main distillate fractions of crude oil were ***,SEM,TPR,ICP-OES,BET-BJH and nitrogen adsorption/desorption methods were used for characterizing the synthesized Ni-Mo/γ-alumina *** active metals with Ni/Mo mass ratio of 0.23 and total metal of 13.7 wt% were loaded on the support,similar to the commercial industrial *** performance tests were conducted at 3.0 MPa(for light naphtha and heavy naphtha)and at 4.5 MPa(for kerosene and gas oil).The results revealed that the total sulfur conversion of the light naphtha,heavy naphtha,kerosene and gas oil fractions was 98.3%,95%,91.7% and 90.1%(after 24 h),respectively.

关键词： HDS HDN Ni-Mo/γ-alumina Gas oil Kerosene Naphtha

Modeling of two-phase particulate flows in a confined jet with a focus on two-way coupling

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Particuology 2018年第4期16卷 78-87页

作者： babak Yousefi-Lafouraki Abas Ramiar Ali Akbar Ranjbar Faculty of Mechanical Engineering Semnan University lran Faculty of Mechanical Engineering Babol Noshirvani University of Technology Iran

A computational fluid dynamics model is used for the simulation of laminar flow ofwater-Al2O3 nanofluid in a confined slot impinging jet. The （steady-state and two-dimensional） Eulerian-Lagrangian model is used considering fluid-particle and particle-wall interactions （i.e., two-way coupling）. A collocated grid and the SIMPLE algorithm are used for the coupling of pressure and velocity fields. The deposition model is used to investigate the effect of particle deposition on the impingement surface. Results indicate that the particle trajectory becomes stable farther from the jet with a rising Reynolds number and jet- impingement surface distance ratio. The heat transfer coefficient of the mixture model is higher than that of the Eulerian-Lagrangican model.

关键词： Eulerian-Lagrangian approach Two-way coupling Particle tracing Mixture model

Bacteriophages and development of nanomaterials for neural regeneration

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Neural Regeneration Research 2014年第22期9卷 1955-1958页

作者： babak Bakhshinejad Majid Sadeghizadeh Department of Genetics Faculty of Biological SciencesTarbiat Modares UniversityTehranIran

Bacteriophages （phages） are viruses that infect bacterial cells and hijack the metabolism of the host cells for replication and amplification of their genetic information. These bacterial viruses are known to be the most numerous life forms on earth. Recent metagenomic analyses have revealed the vast untapped diversity of bacteriophages reinforcing the idea that our current knowledge on the phage world indicates only the tip of the iceberg （Clark, 2012）. The discovery of bacteriophages dramatically expanded the scope of applications of viruses in biotechnology and biomedicine.

关键词： gene NSCs

Optimal design analysis of a tubular heat exchanger network with extended surfaces using multi-objective constructal optimization

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Frontiers in Energy 2022年第5期16卷 862-875页

作者： Hassan HAJABDOLLAHI Mohammad SHAFIEY DEHAJ babak MASOUMPOUR Mohammad ATAEIZADEH Department of Mechanical Engineering Vali-e-Asr University of RafsanjanRafsanjan ***Iran

The present work aims to investigate the influence of extended surfaces(fins)on the multi-objective optimization of a tubular heat exchanger network(THEN).An increase in the heat transfer area using various extended surfaces(fins)to enhance the performance of the heat exchanger was used while considering the effectiveness and total heat transfer area as two objective *** addition to the simulation of simple fins,a new set of fins,called constructal fins,was designed based on the constructal *** heat exchanger network design parameters were chosen as optimization variables,and optimization results were achieved in such a way as to enhance the effectiveness and decrease the total heat transfer *** results show the importance of constructal fins in improving the objective functions of heat *** instance,the simple fins case enhances the effectiveness by up to 5.3%compared to that without fins(usual heat exchanger)while using constructal fins,in addition to the 7%increment of effectiveness,reduces the total heat transfer area by 9.47%.In order to optimize the heat exchanger,the heat transfer rate and cold fluid temperature must increase,and at the same time,the hot exiting fluid temperature should decrease at the same constant total heat transfer area,which is higher in the constructal fins ***,optimized design variables were studied for different cases,and the effects of various fins were reported.

关键词： constructal theory extended surface effectiveness total heat transfer area multi-objective optimization