Seismic response analysis of mega-scale buckling-restrained bracing systems in tall buildings

Gholipour, Mohammadreza,Mazloom, Moosa Techno-Press 2018 Advances in computational design Vol.3 No.1

Tall buildings are categorized as important structures because of the large number of occupants and high construction costs. The choice of competent lateral load resisting systems in tall buildings is of crucial importance. Bracing systems have long been an economic and effective method for resisting lateral loads in steel structures. However, there are some potential adverse aspects to bracing systems such as the limitations they inflict on architectural plans, uplift forces and poor performances in compression. in order to eliminate the mentioned problems and for cost optimization, in this paper, six 20-story steel buildings and frames with different types of bracing, i.e., conventional, mega-scale and buckling-restrained bracing (BRB) were analyzed. Linear and modal push-over analyses were carried out. The results pointed out that Mega-Scale Bracing (MSB) system has significant superiority over the conventional bracing type. The MSB system is 25% more economic. Some other advantages of MSB include: up to 63% less drift ratio, up to 38% better performance in lateral displacement, up to 100% stiffer stories, and about 50% smaller uplift forces. Moreover, MSB equipped with BRB attests even a better seismic behavior in the aforementioned parameters.

Precise prediction of radiation interaction position in plastic rod scintillators using a fast and simple technique: Artifi cial neural network

R. Gholipour Peyvandi,S.Z. Islami rad 한국원자력학회 2018 Nuclear Engineering and Technology Vol.50 No.7

Precise prediction of the radiation interaction position in scintillators plays an important role in medicaland industrial imaging systems. In this research, the incident position of the gamma rays was predictedprecisely in a plastic rod scintillator by using attenuation technique and multilayer perceptron (MLP)neural network, for the first time. Also, this procedure was performed using nonlinear regression (NLR)method. The experimental setup is comprised of a plastic rod scintillator (BC400) coupled with two PMTsat two sides, a 60Co gamma source and two counters that record count rates. Using two proposedtechniques (ANN and NLR), the radiation interaction position was predicted in a plastic rod scintillatorwith a mean relative error percentage less than 4.6% and 14.6%, respectively. The mean absolute errorwas measured less than 2.5 and 5.5. The correlation coefficient was calculated 0.998 and 0.984,respectively. Also, the ANN technique was confirmed by leave-one-out (LOO) method with 1% error. These results presented the superiority of the ANN method in comparison with NLR and the othermethods. The technique and set up used are simpler and faster than other the previous position sensitivedetectors. Thus, the time, cost and shielding and electronics requirements are minimized and optimized.

Effect of semi-rigid connections in improvement of seismic performance of steel moment-resisting frames

M. Gholipour Feizi,A. Mojtahedi,V. Nourani 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.19 No.2

Seismic performances of dual steel moment-resisting frames with mixed use of rigid and semi-rigid connections were investigated to control of the base shear, story drifts and the ductility demand of the elements. To this end, nonlinear seismic responses of three groups of frames with three, eight and fifteen story were evaluated. These frames with rigid, semi-rigid and combined configuration of rigid and semi-rigid connections were analyzed under five earthquake records and their responses were compared in ultimate limit state of rigid frame. This study showed that in all frames, it could be found a state of semi-rigidity and connections configuration which behaved better than rigid frame, with consideration of the base shear and story drifts criterion. Finally, some criteria were suggested to locate the best place of the semi-rigid connections for improvement of the seismic performance of steel moment-resisting frames.

Development of Aluminium‑Nanoclay Composite by Using Powder Metallurgy and Hot Extrusion Process

V. Gholipour,M. Shamanian,A. Ashrafi,A. Maleki 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.9

It is well-known that Al matrix nanocomposites are always more expensive compared to conventional materials. In this study,the Al matrix composite containing montmorillonite Nanoclay reinforcement has been synthesized, which is cheaper andmore abundant than other reinforcements. Powder metallurgy and extrusion process were employed for the production of thenanocomposite samples containing 0%, 1%, 2%, 6%, and 10% Nanoclay. Microstructural evaluations were carried out by usingoptical and scanning electron microscopy. Phase investigation was done by using X-ray diffraction and energy-dispersiveX-ray spectrometer methods. Mechanical evaluations including macro- and micro-hardness, density evaluation, tensile andcompression tests were also conducted. It was revealed that aluminium-clay nanocomposite properties were higher than themonolithic type. According to the obtained results, the addition of montmorillonite Nanoclay caused improvement of themechanical properties, due to the mechanisms like Orowan and thermal expansion mismatch between reinforcement andthe matrix. Thus, the ultimate tensile strengths of 1%, 2%, 6%, and 10% Nanoclay samples were increased about 31%, 46%,62%, and 95%, respectively, than 0% Nanoclay specimen. The sample containing 2% Nanoclay represented the optimumproperties which were the increase in hardness, tensile and compressive strengths about 63%, 46% and 53%, respectively. The increase in the Nanoclay content of the Al matrix changed the complete ductile fracture mode to the shear ductile type.

Seismic design of steel frames using multi-objective optimization

Kaveh, A.,Shojaei, I.,Gholipour, Y.,Rahami, H. Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.2

In this study a multi-objective optimization problem is solved. The objectives used here include simultaneous minimum construction cost in term of sections weight, minimum structural damage using a damage index, and minimum non-structural damage in term of inter-story drift under the applied ground motions. A high-speed and low-error neural network is trained and employed in the process of optimization to estimate the results of non-linear time history analysis. This approach can be utilized for all steel or concrete frame structures. In this study, the optimal design of a planar eccentric braced steel frame is performed with great detail, using the presented multi-objective algorithm with a discrete population and then a moment resisting frame is solved as a supplementary example.

Transition nuclear protein 1 as a novel biomarker in patients with fertilization failure

Jamileh Sadat Mirsanei,Hadis Gholipour,Zahra Zandieh,Masoumeh Golestan Jahromi,Mojgan Javedani Masroor,Mehdi Mehdizadeh,Fatemehsadat Amjadi The Korean Society for Reproductive Medicine 2023 Clinical and Experimental Reproductive Medicine Vol.50 No.3

Objective: Although intracytoplasmic sperm injection (ICSI) is a way to deal with in vitro fertilization failure, 3% of couples still experience repeated fertilization failure after attempted ICSI, despite having sperm within normal parameters. These patients are a challenging group whose sperm cannot fertilize the egg during ICSI. Unfortunately, no test can predict the risk of fertilization failure. Phospholipase C zeta (PLCζ) and transition nuclear proteins (TNPs) are essential factors for chromatin packaging during sperm maturation. This study aimed to assess PLCζ1 and TNP1 expression in the sperm of patients with fertilization failure and the correlations among the DNA fragmentation index, PLCζ1 and TNP1 gene and protein expression, and the risk of fertilization failure. Methods: In this study, 12 infertile couples with low fertilization rates (<25%) and complete failure of fertilization in their prior ICSI cycles despite normal sperm parameters were chosen as the case group. Fifteen individuals who underwent ICSI for the first time served as the control group. After sperm analysis and DNA fragmentation assays, quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and Western blot analyses were performed to compare the gene and protein expression of PLCζ and TNP1 in both groups. Results: DNA fragmentation was significantly higher in the fertilization failure group. The qRT-PCR and Western blot results demonstrated significantly lower PLCζ and TNP1 gene and protein expression in these patients than in controls. Conclusion: The present study showed that fertilization failure in normozoospermic men was probably due to deficient DNA packaging and expression of TNP1.

Optimization of Reinforced Concrete Retaining Walls Via Hybrid Firefly Algorithm With Upper Bound Strategy

Razi Sheikholeslami,Behnam Gholipour Khalili,Ali Sadollah,김중훈 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.6

This paper represents a novel hybrid optimization method that uses an improved firefly algorithm with a harmony search algorithm (IFA-HS), for optimizing the cost of reinforced concrete retaining walls. The IFA-HS is utilized to find an economical design adhering to ACI 318-05 provisions. Two design examples regarding retaining walls are optimized using the proposed hybrid method, and the optimization results confirm the validity and efficiency of the developed algorithm. The IFA-HS method offers improvements on the recently developed firefly algorithm. These improvements include utilizing the memory that contains information extracted online during a search, employing pitch adjusting operation of HS during firefly updates, and modifying the movement phase of the FA. Moreover, to decrease the computational effort of the IFA-HS, the upper bound strategy, which is a recently developed strategy for reducing the total number of structural analyses, is incorporated during the optimization process.

The Effect of Bulk Electrospun Polycaprolactone-graphene Oxide Scaffold on the Healing of Defected Femur Cartilage on a Rabbit Model

Farnaz Moradi,Adeleh Gholipour-Kanani,Najmeh Najmoddin,Niloofar Eslahi,S. Hajir Bahrami,Shahram Rabbani 한국섬유공학회 2021 Fibers and polymers Vol.22 No.5

In this study, bulk and non-bulk electrospun scaffolds from polycaprolactone (PCL) containing graphene oxide(GO) were fabricated. Graphene oxide with 0.3, 0.5, and 1 wt% was added to different concentrations of PCL solutions undersonication. The blends were electrospun under varied conditions of 10-20 kV applied voltages, a distance of 10 to 20 cm, anda 0.5 ml/hr flow rate. The web of PCL(10 %)-GO(0.5 %) was selected as an optimum one via scanning electron microscopy(SEM) images, which exhibited uniform morphology with a 257±18 nm average diameter. The fourier transform infrared(FTIR) results showed that the specified peaks of both PCL and GO in the blends. Mechanical investigation exhibited higherstrength of the PCL-GO web (about 4.3 MPa) compare to the PCL web. The porosity of the webs was measured bydensitometry, which showed an increase in porosity from 80 % to 92 % after the bulking process (ultra-sonication, followedby freeze-drying). The MTT assay was employed using human adipose-derived mesenchymal stem cells (hAMSCs) on thescaffolds. Results indicated that the cell viability of bulk and non-bulk PCL-GO scaffolds were about 98 % and 99.8 %,respectively. In vivo study was carried out on defected cartilage knees of fourteen New Zealand rabbits. For monitoring thecartilage repair, magnetic resonance imaging (MRI) as well as pathological investigations were performed after surgery. Theresults of MRI and H&E staining showed high qualified healing of defects, which were exposed to bulk nanofibrous scaffold. Therefore, bulk PCL-GO electrospun scaffolds can be introduced as a suitable scaffolds for cartilage regeneration.

Design and engineering of sculptured nano-structures for application in hydrophobicity

Somaye Hosseini,Hadi Savaloni,Mehran Gholipour Shahraki 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.45 No.-

The design and engineering of suitable structures for enhancement of the hydrophobic property of asurface is one of the most challenging problems. In order to achieve a superhydrophobic structure wehave designed and fabricated Mn nano-sculptured thinfilms with different shapes and dimensions,namely helical squares and helical pentagons on glass substrates. The contact angle (CA) of three liquids;a–bromonaphtalene (apolar), water and formamide (polar) to these surfaces was measured and thesurface free energy was calculated. Changes to the geometry of the structure produced results rangingfrom hydrophilic (CA = 51 ) to superhydrophobic (CA = 152 ). The superhydrophobic structure is a helicalsquare shaped structure with high porosity (deposited at 83 ) which also shows the rose petal effect withthe additional property of high adhesion. The resemblance of this structure to that of gecko feet, whichshows both high adhesion forces and superhydrophobic property is discussed. All structures investigatedin this work showed negative spreading coefficients with highest values for the largest contact angle foreach type/shape of structure. The superhydrophobic sample also acts as a sticky surface which isconfirmed by hysteresis of the contact angle obtained from advancing and receding contact anglesmeasurements. The influence of the volume of liquid drop and different surface morphologies on thewetting transition from Cassie–Baxter to Wenzel states is also reported.

Seismic design of steel frames using multi-objective optimization

A. Kaveh,I. Shojaei,Y. Gholipour,H. Rahami 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.2

In this study a multi-objective optimization problem is solved. The objectives used here include simultaneous minimum construction cost in term of sections weight, minimum structural damage using a damage index, and minimum non-structural damage in term of inter-story drift under the applied ground motions. A high-speed and low-error neural network is trained and employed in the process of optimization to estimate the results of non-linear time history analysis. This approach can be utilized for all steel or concrete frame structures. In this study, the optimal design of a planar eccentric braced steel frame is performed with great detail, using the presented multi-objective algorithm with a discrete population and then a moment resisting frame is solved as a supplementary example.