http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Saeed Kamarian,Ali Khalvandi,Thanh Mai Nguyen Tran,Reza Barbaz-Isfahani,Saeed Saber-Samandari,Jung-Il Song Techno-Press 2023 Advances in nano research Vol.15 No.4
The main goal of the present study was to assess the effects of eggshell powder (ESP) and halloysite nanotubes (HNTs) on the mechanical properties of abaca fiber (AF)-reinforced natural composites. For this purpose, a limited number of indentation tests were first performed on the AF/polypropylene (PP) composites for different HNT and ESP loadings (0 wt.% ~ 6 wt.%), load amplitudes (150, 200, and 250 N), and two types of indenters (Vickers or conical). The Young's modulus, hardness and plasticity index of each specimen were calculated using the indentation test results and Oliver-Pharr method. The accuracy of the experimental results was confirmed by comparing the values of the Young's modulus obtained from the indentation test with the results of the conventional tensile test. Then, a feed-forward shallow artificial neural network (ANN) with high efficiency was trained based on the obtained experimental data. The trained ANN could properly predict the variations of the mentioned mechanical properties of AF/PP composites incorporated with different HNT and ESP loadings. Furthermore, the trained ANN demonstrated that HNTs increase the elastic modulus and hardness of the composite, while the incorporation of ESP reduces these properties. For instance, the Young's modulus of composites incorporated with 3 wt.% of ESP decreased by 30.7% compared with the pure composite, while increasing the weight fraction of ESP up to 6% decreased the Young's modulus by 34.8%. Moreover, the trained ANN indicated that HNTs have a more significant effect on reducing the plasticity index than ESP.
Numerical cyclic behavior of T-RBS: A new steel moment connection
Saeed Ataollahi,Mohammad-Reza Banan,Mahmoud-Reza Banan 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.21 No.6
After observing relatively poor performance of bolted web-welded flange beam-to-column connections during 1994 Northridge earthquake, various types of connections based on two concepts of: (i) strengthening the connection; and (ii) weakening the beam ends were proposed. Among these modified or newly proposed connections, bolted T-stub connection follows the concept of strengthening. One of the connections with the idea of weakening the beam ends is reduced beam section (RBS). In this paper, finite element simulation is used to study the cyclic behavior of a new proposed connection developed by using a combination of both mentioned concepts. Investigated connections are exterior beam-to-column connections designed to comply with AISC provisions. The results show that moment capacity and dissipated energy of the new proposed connection is almost the same as those computed for a T-stub connection and higher than corresponding values for an RBS connection.
Regularizing structural configurations by using meta-heuristic algorithms
Massah, Saeed Reza,Ahmadi, Habibullah Techno-Press 2017 Geomechanics & engineering Vol.12 No.2
This paper focuses on the regularization of structural configurations by employing meta-heuristic optimization algorithms such as Particle Swarm Optimization (PSO) and Biogeography-Based Optimization (BBO). The regularization of structural configuration means obtaining a structure whose members have equal or almost equal lengths, or whose member's lengths are based on a specific pattern; which in this case, by changing the length of these elements and reducing the number of different profiles of needed members, the construction of the considered structure can be made easier. In this article, two different objective functions have been used to minimize the difference between member lengths with a specific pattern. It is found that by using a small number of iterations in these optimization methods, a structure made of equal-length members can be obtained.
Aghdam, Saeed Mahboubi,Sardari, Zeinab,Safaralizadeh, Reza,Bonyadi, Mortaza,Abdolmohammadi, Reza,Moghadam, Mostafa Soltani,Khalilnezhad, Ahad Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.19
Background: H pylori is the main causative agent of Gastric cancer and chronic gastritis. Genetic diversity of H. pylori has major contribution in its pathogenesis. We investigated the prevalence of oipA and iceA1/iceA2 positive strains of H. pylori among patients with gastric cancer and gastritis. Materials and Methods: Sampling performed by means of endoscopy from 86 patients. DNA was extracted from tissue samples using DNA extraction kit. PCR assay was performed and products were monitored by Agarose Gel Electrophoresis. Results: Urease Test and 16S rRNA PCR did not show significant differences in detection of H. pylori. The frequency of iceA1 allele in patients with gastric cancer was significantly higher than those with gastritis (p<0.05). However, there was no significant difference in prevalence of oipA and iceA2 genes among the two groups of patients (p>0.05). Conclusions: The iceA1 gene, but the oipA and iceA2 genes, is associated with H. pylori-induced gastric cancer. However, confirmatory studies must be performed in future.
Kasiri, Reza,Massah, Saeed Reza Techno-Press 2022 Advances in nano research Vol.12 No.1
Due to the extensive use of concrete structures in various applications, the improvement of their strength and quality has become of great importance. A new way of achieving this purpose is to add different types of nanoparticles to concrete admixtures. In this work, a mathematical model has been employed to analyze the vibration of concrete beams reinforced by graphene oxide (GO) nanoparticles. To verify the accuracy of the presented model, an experimental study has been conducted to compare the compressive strengths of these beams. Since GO nanoparticles are not readily dissolved in water, before producing the concrete samples, the GO nanoparticles are dispersed in the mixture by using a shaker, magnetic striker, ultrasonic devices, and finally, by means of a mechanical mixer. The sinusoidal shear deformation beam theory (SSDBT) is employed to model the concrete beams. The Mori-Tanaka model is used to determine the effective properties of the structure, including the agglomeration influences. The motion equations are calculated by applying the energy method and Hamilton's principle. The vibration frequencies of the concrete beam samples are obtained by an analytical method. Three samples containing 0.02% GO nanoparticles are made and their compressive strengths are measured and compared. There is a good agreement between our results and those of the mathematical model and other papers, with a maximum difference of 1.29% between them. The aim of this work is to investigate the effects of nanoparticle volume fraction and agglomeration and the influences of beam length and thickness on the vibration frequency of concrete structures. The results show that by adding the GO nanoparticles, the vibration frequency of the beams is increased.
Ghasemi Arman,Ramazani Mazaher,Bakhshi Saeed Reza,Al-Khafaji Ali Hussein Demin,Zahabi Saeed,Loghman Estarki Mohammad Reza,Zamani Abbas 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.4
This research aims to fabricate and develop a composite brake disc made of carbon/silicon carbide. For this purpose, the first silicon carbide nanoparticles were ultrasonicated with alumina sintering aid and carbon fi ber (between 10 and 20%) with different lengths of 3 mm, 10 mm, and 15 mm. Next, the fi nal Cf/SiC composite bulk was made-up via the spark plasma sintering (SPS) method. After that, the effect of different lengths of carbon fiber was explored on the porosity, coefficient of friction, fracture toughness, thermal conductivity, and microhardness of samples. The results showed that the density of sintered samples with a carbon fiber length of 10 mm was higher than that of samples with fiber lengths of 3 and 15 mm. Also, the hardness (25.79 GPa) and fracture toughness (5.72 MPa.m 1/2) of this sample were higher than those of the samples sintered with carbon fiber lengths of 3 and 15 mm. Further, this sample with the maximum density showed a coefficient of friction (COF) of 0.43. Since for aeroplane brake discs, the COF should be between 0.3 and 0.4, and the porosity of sam- ples should range within 3–5%, the samples sintered with the carbon fiber length of 10 mm had the nearby features to the preferred air brake disc indices.