EXPERIMENTAL RESULTS OF PRESSURE VARIATION IN TWO-PHASE AIR-WATER FLOW IN WATER TUNNELS

KABIRI-SAMANI ABDORREZA 한국수자원학회 2005 한국수자원학회 학술대회 Vol.2005 No.1

Preparation and characterization of absorbable hemostat crosslinked gelatin sponges for surgical applications

Maryam Kabiri,Shahriar Hojjati Emami,Mohammad Rafinia,Mohammadreza Tahriri 한국물리학회 2011 Current Applied Physics Vol.11 No.3

The aim of this study, is synthesis of an absorbable hemostat gelatin sponge crosslinked with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC). The effects of various gelatin contents and crosslinking agent concentrations, freezing temperature on the mechanical properties, rate of biodegradation in 24 h,hemolytic ability and cell viability of sponges were investigated. The results of scanning electron microscopy (SEM) showed that freezing temperature had a significant effect on the structure and density of sponges. SEM views of the sponges demonstrated that they have pores with mean diameters of 180―280 μm. Fourier transform infrared (FTIR) spectra indicated that there is no residual of the crosslinking agent in the structure of final gelatin sponges because of C―N bonds (urea derivatives) absence. The sample with 1% gelatin and 0.05% EDC freezed at ―25 ℃ (before freeze-drying) showed more than 0.37 cm^-1 UV absorption of hemoglobin or blood clotting in half an hour. The compression modulus of the same sample was more than 150 kPa and percentage of degradation was about 28% in 24 h.

3D Trajectory Tracking Control for a Thrust-Propelled Vehicle with Time-varying Disturbances

Meisam Kabiri,Hajar Atrianfar,Mohammad Bagher Menhaj 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.8

This paper discusses trajectory tracking for a class of under-actuated thrust-propelled vehicle in thepresence of two time-varying disturbances. A saturated estimator based on equivalent output injection slidingmode disturbance observer is employed to accommodate for the adverse effect of the translational disturbance. Tohandle the rotational disturbance, we make use of a sliding mode controller. The stability of the overall systemis investigated by means of Lyapunov function theory. A numerical simulation is included in the paper to showeffectiveness of the proposed control scheme.

Compression failure and fiber-kinking modelingof laminated composites

A. Kabiri Ataabadi,S. Ziaei-Rad,H. Hosseini-Toudeshky 국제구조공학회 2012 Steel and Composite Structures, An International J Vol.12 No.1

In this study, the physically-based failure models for matrix and fibers in compression and tension loading are introduced. For the 3D stress based fiber kinking model a modification is proposed for calculation of the fiber misalignment angle. All of these models are implemented into the finite element code by using the advantage of damage variable and the numerical results are discussed. To investigate the matrix failure model, purely in-plane transverse compression experiments are carried out on the specimens made by Glass/Epoxy to obtain the fracture surface angle and then a comparison is made with the calculated numerical results. Furthermore, shear failure of (±45)s model is investigated and the obtained numerical results are discussed and compared with available experimental results. Some experiments are also carried out on the woven laminated composites to investigate the fracture pattern in the matrix failure mode and shown that the presented matrix failure model can be used for the woven composites. Finally, the obtained numerical results for stress based fiber kinking model and improved ones (strain based model) are discussed and compared with each other and with the available results. The results show that these models can predict the kink band angle approximately.

Nonlinear Buckling Analysis of Cones with Rectangular Cutouts, Numerical and Experimental Investigation

Mohammad Javad Kabiri Renani,Javad Jafari Fesharaki 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.1

In this paper a new regression relation for nonlinear ultimate buckling resistance of the cones with rectangular cutouts is presented. For this purpose, the eff ective geometry parameters and material properties such as the length, thickness, large diameter and angle of the cone, the length, width and location of cutout, the modulus of elasticity, yield stress and plastic properties are considered. Then using response surface method, 288 design of experiment is considered and a regression relation for predict the ultimate buckling resistance is proposed. To validate the results, two types of real experiment are presented and the results show that there is good agreement between the experimental tests and proposed relation. Then the eff ects of changing the various parameters on the ultimate buckling resistance of the cone are investigated. The results show that locating the cutout near the large diameter of the cone has more infl uence than locating near the small diameter. Also, the location of cutout has more infl uence at higher thickness. Also, the yield stress has more infl uence on ultimate buckling resistance at higher values of thickness. In addition, decreasing the length of the cone or increasing the diameter of the cone increase the ultimate buckling resistance and increasing the angle of cone decrease the ultimate buckling resistance of the cone

PRESSURE VARIATION DUE TO SUDDEN RISE OF WATER HEAD AT WATER INLETS

SAMANI ABDORREZA KABIRI,BORGHEI SEIED MAHMOOD,SAIDI MOHAMMAD HASSAN 한국수자원학회 2005 한국수자원학회 학술대회 Vol.2005 No.1

Heparin-coated Poly(ethylene terephthalate)/Graphene Oxide Nanofibers Used for Vascular Tissue Engineering Application

Romina Sepehri,Payam Zahedi,Mahboubeh Kabiri,Chakavak Nojavan 한국섬유공학회 2022 Fibers and polymers Vol.23 No.11

Coating polymeric nanofibers with anti-coagulant agents is one of the most important methods to enhance theperformance of these materials against blood interactions. In this work, poly(ethylene terephthalate) (PET)/graphene oxide(GO) nanofibers coated with heparin (Hep) were fabricated and their physicochemical properties alongside hemocompatibilitywere investigated. To study the effect of GO on PET nanofibers, the electrical conductivity of 4.08×10-8 S cm-1 and elasticmodulus of approximately 47 MPa for sample containing 3 wt.% of GO (PET/GO 3) were observed. After NH3 plasma, Hepwas coated on the optimal PET/GO 3 nanofibrous sample and Fourier transform infrared spectroscopy as well as watercontact angle results exhibited the appropriate Hep coating by dedicating characteristic peak of 1187 cm-1 and 25 °,respectively. In addition, the scanning electron microscopic images of PET/GO 3 nanofibers showed Hep coating has nosignificant influence on the size of nanofibrous diameter. Prothrombin time and partial thromboplastin time were increasedup to 106 s and 350 s; additionally, the number of platelets and hemolytic index were decreased in PET/GO 3 nanofibers inpresence of Hep. Eventually, cultivation of mesenchymal stem cells revealed that the sample coated with Hep dedicated thehighest cell proliferation with the most living cells. The overall outcomes conducted us the Hep-coated PET/GO 3nanofibrous sample was a promising candidate for vascular tissue engineering.

Preparation and Investigation on Swelling and Drug Delivery Properties of a Novel Silver/Salep-g-Poly(Acrylic Acid) Nanocomposite Hydrogel

Ghasem Rezanejade Bardajee,Zari Hooshyar,Firozeh Kabiri 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.8

Novel silver/salep-g-poly(acrylic acid) nanocomposite hydrogel were prepared in aqueous solution using poly(acrylic acid) grafted onto salep as a biopolymer based material. FT-IR spectra confirmed that poly(acrylic acid) (PAA) had been grafted onto salep in graft copolymerization reaction. TEM observations showed that silver nanoparticles have been uniformly dispersed in polymeric matrix. Effects of pH, acrylic acid (AA) amount and silver ion concentration on swelling capabilities were investigated. Results indicate that modifying AA and silver ion can improve swelling properties of the resultant nanocomposite hydrogel. pH response of this nanocomposite hydrogel in acidic and neutral pH made it suitable for drug delivery applications.

Radical Copolymerization of Acrylic Acid and OEGMA475: Monomer Reactivity Ratios and Structural Parameters of the Copolymer

Hossein Abdollahi,Vahid Najafi,Farshid Ziaee,Kourosh Kabiri,Farhad Narimani 한국고분자학회 2014 Macromolecular Research Vol.22 No.12

Alternative copolymers of acrylic acid (AA) and oligo(ethylene glycol) methyl ether methacryate (475 g/mol (OEGMA475)) macromer, having various amounts of two monomers, were synthesized using aqueous solutionfree radical copolymerization at 50 °C with ammonium persulfate (APS) as an initiator. The structures of the copolymerswere confirmed by nuclear magnetic resonance (NMR) spectroscopy. In fact, samples with different molarratios of two monomers in deionized water were prepared and subsequently copolymerization reaction was performedto low conversion levels (below 10%). Monomer reactivity ratios of OEGMA475, AA pair were estimatedusing the Finemann-Ross (FR), inverted Finemann-Ross (IFR), Kelen-Tüdös (KT), extended Kelen-Tüdös (EKT),Mayo-Lewis (ML) and Yezrelieve-Brokhina-Roskin (YBR) graphical methods. The value ranged from 0.908 to0.963 for rOEGMA and from 0.208 to 0.243 for rAA depending on conversion percentage and calculation methods ofmonomer reactivity ratios. In all the cases, rOEGMA×rAA<1 and rOEGMA>rAA indicate that the resulting copolymer has atendency toward alternation with an azeotropic point in MOEGMA=0.905. Structural parameters of the copolymerswere obtained by calculating the dyad monomer sequence fractions and the mean sequence length. Keywords: oligo(ethylene glycol) methyl ether methacrylate, acrylic acid, monomer reactivity ratios, altern

Melatonin improves antioxidant defense mechanism of basil under drought stress

Naghizadeh Mehdi,Reiter Russel J.,Kabiri Rozita,Moradi Rooholla 한국원예학회 2024 Horticulture, Environment, and Biotechnology Vol.65 No.1

Basil ( Ocimum basilicum L.) is a highly important medicinal plant. In this study, the interactional eff ects of water defi cit and melatonin application on growth and physio-biochemical characteristics of basil were investigated. The treatments included three levels of irrigation (100, 75 and 50% of fi eld capacity) and three melatonin concentrations (0, 50 and 100 μmol). Drought stress decreased the dry weight of plants but application of 100 μmol melatonin markedly increased dry weight under these conditions. Melatonin profoundly enhanced plant drought tolerance by stimulating the antioxidant enzymes (catalase, phenylalanine ammonia-lyase, ascorbate peroxidase and polyphenol oxidase) activities and secondary metabolites (total phenol, fl avonoid and anthocyanin contents). Furthermore, melatonin application reduced lipid peroxi dation and increased the relative water content and photosynthetic pigments, resulting in an improvement of plant dry matter. It is concluded that foliar spraying with melatonin induced the pre-adaptive responses to drought stress followed by regulating antioxidant defense mechanisms.