Weight and topology optimization of outrigger-braced tall steel structures subjected to the wind loading using GA

Nouri, Farshid,Ashtari, Payam Techno-Press 2015 Wind and Structures, An International Journal (WAS Vol.20 No.4

In this paper, a novel methodology is proposed to obtain optimum location of outriggers. The method utilizes genetic algorithm (GA) for shape and size optimization of outrigger-braced tall structures. In spite of previous studies (simplified methods), current study is based on exact modeling of the structure in a computer program developed on Matlab in conjunction with OpenSees. In addition to that, exact wind loading distribution is calculated in accordance with ASCE 7-10. This is novel since in previous studies wind loading distributions were assumed to be uniform or triangular. Also, a new penalty coefficient is proposed which is suitable for optimization of tall buildings. Newly proposed penalty coefficient improves the performance of GA and results in a faster convergence. Optimum location and number of outriggers is investigated. Also, contribution of factors like central core and outrigger rigidity is assessed by analyzing several design examples. According to the results of analysis, exact wind load distribution and modeling of all structural elements, yields optimum designs which are in contrast of simplified methods results. For taller frames significant increase of wind pressure changes the optimum location of outriggers obtained by simplified methods. Ratio of optimum location to the height of the structure for minimizing weight and satisfying serviceability constraints is not a fixed value. Ratio highly depends on height of the structure, core and outriggers stiffness and lateral wind loading distribution.

Using Resveratrol and Epigallocatechin-3-Gallate to Improve Cryopreservation of Stallion Spermatozoa With Low Quality

Nouri, Houshang,Shojaeian, Kamal,Samadian, Farhad,Lee, Soojung,Kohram, Hamid,Lee, Jeong Ik Elsevier 2018 Journal of equine veterinary science Vol.70 No.-

<P><B>Abstract</B></P> <P>Reactive oxygen species levels in semen with low quality increased from 25% to about 40%. Resveratrol (Res) is a natural grape-derived phytoalexin, and epigallocatechin-3-gallate (EGCG) is the major polyphenol in green tea (<I>Camellia sinensis</I>); both molecules are known to have high levels of antioxidant activity. The aim of this study was to investigate the effects of this antioxidant's supplementation on cryopreservation of stallion semen with poor quality. Experiment 1: Experiment design to asses stallions semen quality (n = 3). Arabian stallions were managed for breeding with fresh, extended, or chilled semen during 2 years (in two breeding season) with a resulting per cycle pregnancy rate (103/41 estrus cycle/conception) of 39.80%. A total of 81 ejaculates were collected and evaluated in fresh condition (total and progressive motility, membrane integrity, acrosome defects, morphology, and abnormal DNA condensation). Evaluation of several ejaculates revealed that sperm production and semen quality mostly did not change during the breeding season, maintaining normal sperm production with poor quality. Experiment 2: 18 ejaculates, collected with Missouri model artificial vagina from Arabian stallion (n = 3). Extended semen was centrifuged at 600 × g for 10 minutes. To eliminate individual stallion variability, the resulting sperm pellets were pooled and divided in seven different treatments in a final concentration of 100 × 10<SUP>6</SUP> sperm/mL by using semiskimmed milk extender containing no supplements (control), and the following supplements with three different concentrations: Res 5, 10, and 20 μM (Res 1, Res 2, Res 3, respectively) and EGCG 25, 50, 100 μM (EGCG 1, EGCG 2, and EGCG 3, respectively). After thawing, all samples were maintained at 37°C for 10 minutes. Evaluation of motility, plasma membrane integrity, viability, mitochondria activity, DNA fragmentation, and lipid peroxidation was determined. For all semen parameters, the lower concentration of Res (5 μM) and EGCG (25 μM) did not show significant differences compared to control (<I>P</I> > .05). Relative to the control group, Res 2 had better (<I>P</I> < .05) postthaw total and progressive motility, yet the higher concentrations (Res 3) showed a negative effect on total motility. Percentage of membrane integrity, viability, and mitochondrial activity was significantly greater in Res 2 and EGCG 2 extenders in comparison with the control group, respectively (<I>P</I> < .05). Results showed that malondialdehyde concentration was lower in Res 2 and EGCG 2 groups. In conclusion, the present study showed that the antioxidant Res prevents DNA damages in our stallions. The addition of Res and EGCG before cryopreservation can ameliorate mitochondrial activity in stallions with low-quality semen. Although further studies are needed, the present work showed that Res and EGCG could be considered as cryopreservation procedures in stallions with low-quality sperm and possibly equine, to avoid or minimize DNA damages, and preserve sperm plasma membrane integrity and mitochondrial activity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The aim of this study was to investigate the effects of resveratrol (Res) and epigallocatechin-3-gallate (EGCG) supplementation on cryopreservation of stallion (n = 3) spermatozoa with poor quality. </LI> <LI> Five micromolar of Res and 50 μM EGCG in semiskimmed milk extender before cryopreservation can ameliorate total and progressive motility, percentage of membrane integrity, and viability in stallions with low quality. </LI> <LI> In conclusion, the present study showed that the 5 μM Res could prevent DNA damages in subfertile stallions. </LI> <LI> Although further studies are needed, the present work showed that Res and EGCG could be considered as cryopreservation procedures in stallions with low-quality sperm and possibly equine, to avoid or minimize DNA damag

A New AC/DC Converter for the Interconnections between Wind Farms and HVDC Transmission Lines

Nouri, Soheil,Babaei, Ebrahim,Hosseini, Seyyed Hossein The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.3

In this paper, a new ac/dc converter is proposed for HVDC-connected wind farms. The proposed converter provides a suitable dc voltage for HVDC transmission systems. Each wind turbine is connected to two full bridge diode rectifiers. These rectifiers are connected to each other by three thyristors. Firing the thyristors at desired angles provides an adjustable dc voltage in the output of the converter. Simulation results show the efficiency of the proposed converter.

Investigation of direct extrusion channel effects on twist extrusion using experimental and finite element analysis

Nouri, Mehran,Mohammadian Semnani, Hamidreza,Emadoddin, Esmaeil,Seop Kim, Hyoung Elsevier 2018 MEASUREMENT -LONDON- Vol.127 No.-

<P><B>Abstract</B></P> <P>Twist extrusion (TE) is a relatively new severe plastic deformation technique in which radial deformation is heterogeneously distributed in the sample. In this research, in order to achieve favorable properties, a direct extrusion (DE) channel was embedded after the twist zone at the bottom of the TE die. The plastic deformation behavior of aluminum alloy 6063 (AA6063) was investigated in the TE process, with and without the DE channel. AA6063 successfully underwent TE under the conditions designed using the finite element analysis. According to the simulation results, a very heterogeneous distribution of the equivalent plastic strain (PEEQ) was observed in TE, while the TE+DE simulation exhibited more homogeneous PEEQ in the central and lateral regions. Microstructural evolution analysis using scanning electron microscope and Vickers microhardness evaluations showed that utilizing the DE channel increased the hardness and provided a more homogenous microstructure. Moreover, tensile testing results indicated an increase in strength and enhanced mechanical properties of the TE+DE processed AA6063.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Innovative twist extrusion was achieved by embedding a direct extrusion channel after the twist zone. </LI> <LI> Finite element analysis showed that the direct extrusion channel decreased sample deformation heterogeneity. </LI> <LI> All data indicated that absence of sufficient back pressure led to distortion and elongation of samples. </LI> <LI> The best microstructure was achieved by combining twist extrusion and direct extrusion channel. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Experimental investigation of the effect of baffles on the efficiency improvement of irrigation sedimentation tank structures

Nouri, Alireza Zamani,Heydari, Mohammad Mehdi Techno-Press 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.4

Sedimentation tanks are essential structures to filter the suspended sediments in the inlet flow which are constructed at the inlet of the basins forked from rivers and irrigation canals. The larger the constructed tank, the better the sedimentation process is conducted. However, the construction and dredging costs increase. In this regard, improving the performance and sedimentation efficiency seem necessary by alternative methods. One of these effective methods is using baffle plates. Most of the studies carried out in this field are on the use of these baffles in the primary and secondary sedimentation tanks. Hence, this study is carrier out with the objective of increasing the retention efficiency in the irrigation sedimentation tanks using baffles. To reach this goal, the experiments were carried out in a flume with length 8 meters, width 0.3 meters, and height 0.5 meters, considering a sedimentation tanks with a length of 3 meters, in three different inlet concentration, three flow rates and three Froude numbers. The baffles were mounted at the bottom of the tank and the effects of the angle, height and position in the tanks were investigated. The results showed that on average, employing the baffles increased the sedimentation efficiency 5 to 6% and the highest value was obtained for angle 60 with respect to the flow direction. According to the results of this study, the most favorable height and position of these baffles were obtained to be in 40% of the depth of the flow and 50% of the length of the sedimentation tank, respectively. Also, by increasing the number of baffles, the sedimentation efficiency decreased. Regarding the sedimentation regions in this case, more than 80% of the settled sediments were observed in the middle of the tank measured from the inlet.

Microstructure and Mechanical Properties of Powder Thixoforged Amorphous Ni55Nb35Si10-Reinforced Al Matrix Composites

Nouri, Z.,Sedighi, M. Springer-Verlag 2019 JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE Vol.28 No.2

An investigation on the properties and microstructure of mullite-bonded cordierite ceramics

M.Nouri. Khezrabadi,R. Naghizadeh,P. Assadollahpour,S.H. Mirhosseini 한양대학교 세라믹연구소 2007 Journal of Ceramic Processing Research Vol.8 No.6

The fabrication of a mullite-bonded cordierite body suitable for use as kiln furniture has been investigated in this article. First of all cordierite powder was synthesized by mixing talc, kaolin and alumina as starting materials, pressing and firing up to 1325oC. The amount of cordierite phase was estimated by an X-ray diffraction technique. The synthesized cordierite was then mixed with certain amounts of kaolin and alumina as the starting materials for mullite formation and the mixture was shaped by a pressing method, following by firing at different temperatures. The changes of density, porosity and cold crushing strength of the samples were measured as a function of heat treatment temperature. The results showed that these properties improve by a rise in temperature. The mullite formation within the samples was confirmed by an XRD method. The thermal expansion coefficient of the samples fired at 1350oC was determined by a dilatometer having an average value of 3.18×10−6 (1/K), which indicates an excellent thermal shock resistant for the samples. The microstructure of the fired samples was studied using scanning electron microscopy (SEM), which showed interesting results. The fabrication of a mullite-bonded cordierite body suitable for use as kiln furniture has been investigated in this article. First of all cordierite powder was synthesized by mixing talc, kaolin and alumina as starting materials, pressing and firing up to 1325oC. The amount of cordierite phase was estimated by an X-ray diffraction technique. The synthesized cordierite was then mixed with certain amounts of kaolin and alumina as the starting materials for mullite formation and the mixture was shaped by a pressing method, following by firing at different temperatures. The changes of density, porosity and cold crushing strength of the samples were measured as a function of heat treatment temperature. The results showed that these properties improve by a rise in temperature. The mullite formation within the samples was confirmed by an XRD method. The thermal expansion coefficient of the samples fired at 1350oC was determined by a dilatometer having an average value of 3.18×10−6 (1/K), which indicates an excellent thermal shock resistant for the samples. The microstructure of the fired samples was studied using scanning electron microscopy (SEM), which showed interesting results.

Economic Injury Level for Colorado Potato Beetle, Leptinotarsa decemlineata (Say), on Draga Potatoes in Ardebil

G. Nouri-Ganbalani 한국응용곤충학회 2005 한국응용곤충학회 학술대회논문집 Vol.2005 No.05

Development of jute rope hybrid composite plate using carbon fibre

Karim Nouri,Md. Ashraful Alam,Mohammad Mohammadhassani,Mohd Zamin Bin Jumaat,Amir Hosein Abna 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.56 No.6

Jute rope is one of the most popular materials used for composites in various industries and in civil engineering. This experimental study investigated two types of jute rope with different diameters for jute rope composite plates to determine the best combination of jute rope and carbon fiber in terms of ratio and physical and mechanical properties. Eight combinations of carbon fiber and jute rope with different percentages of carbon fiber were analyzed. Tensile tests for the jute rope composite plate and hybrid jute rope composite were conducted, and the mechanical and physical properties of the specimens were compared. Thereafter, the ideal combinations of jute rope with an optimum percentage of carbon fiber were identified and recommended. These particular combinations had tensile strengths that were 2.23 times and 1.76 times higher than other varieties in each type.

Experimental and numerical analyses of perforated corrugated steel shear walls

Gholamreza Nouri,Arash Rayegani,Fariba Nemati,Gholam Hossein Eftekhar 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.12

This study presents an evaluation of the seismic performance of corrugated steel shear walls (CSSWs) with openings. Cyclic experimental tests were conducted on CSSW specimens featuring square and circular openings, with a comparison made to infill CSSWs. Additionally, numerical analysis was performed to investigate various opening configurations. The results indicate that CSSWs with openings experienced a maximum strength reduction of approximately 10% when compared to infill walls. Furthermore, placing the opening at the center of the wall resulted in an elastic stiffness decrease of approximately 23%. The presence of openings also mitigated the pinching effect observed in cyclic responses. The numerical analysis further revealed that incorporating stiffeners around the openings significantly enhanced the seismic performance of CSSWs. Stiffened openings demonstrated improvements of approximately 38% in ultimate strength, 26% in stiffness, 25% in ductility reduction factor, and 15% in equivalent viscous damping ratio when compared to unstiffened openings. To further investigate the practical application, the study numerically evaluated 3-story frames with perforated CSSWs under monotonic loading. The analysis demonstrated the beneficial impact of opening stiffeners, as stiffened openings exhibited increased ductility, loading capacity, initial stiffness, and response behavior factor of approximately 13.5%, 9.0%, 20.5%, and 30%, respectively, when compared to unstiffened perforated CSSWs. Overall, this study contributes to the understanding of the seismic behavior of CSSWs with openings and highlights the advantages of incorporating stiffeners around the openings to enhance their structural performance.