Triangular units based method for simultaneous optimizations of planar trusses

Mortazavi, Ali,Togan, Vedat Techno-Press 2017 Advances in computational design Vol.2 No.3

Simultaneous optimization of trusses which concurrently takes into account design variables related to the size, shape and topology of the structure is recognized as highly complex optimization problems. In this class of optimization problems, it is possible to encounter several unstable mechanisms throughout the solution process. However, to obtain a feasible solution, these unstable mechanisms somehow should be rejected from the set of candidate solutions. This study proposes triangular unit based method (TUBM) instead of ground structure method, which is conventionally used in the topology optimization, to decrease the complexity of search space of simultaneous optimization of the planar truss structures. TUBM considers stability of the triangular units for 2 dimensional truss systems. In addition, integrated particle swarm optimizer (iPSO) strengthened with robust technique so called improved fly-back mechanism is employed as the optimizer tool to obtain the solution for these class of problems. The results obtained in this study show the applicability and efficiency of the TUBM combined with iPSO for the simultaneous optimization of planar truss structures.

Solving structural optimization problems with discrete variables using interactive fuzzy search algorithm

Ali Mortazavi 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.79 No.2

The current investigation deals with assessing the search performance of a recently developed, parameter-free, and self-adaptive search algorithm so-called Interactive Fuzzy Search Algorithm (IFSA) in solving weight minimization of the constrained structural optimization problems with discrete variables. The proposed IFSA combines the navigation pattern of the Interactive Search Algorithm (ISA) with the decision-making competence of fuzzy reasoning. The fuzzy module of the proposed IFSA permanently monitors the search process and adjusts each agent's search behavior by considering the governing condition of the current problem. In structural optimization, due to construction limitations, it is more realistic to select the sizing variables from a discrete domain. Thus, in this study, to empirically evaluate the search capability of the IFSA, it is applied to solve a suite of structural optimization problems with the discrete design variables. The attained outcomes are compared with the ISA and some other related methods addressed in the relevant literature. The acquired accuracy level and demanded number of objective function evaluations indicates that the IFSA, comparatively, using lower computational cost could found lighter structural systems. Also, the comparison of the attained standard deviation values shows that the IFSA demonstrates higher stability during the optimization process. These superior outcomes designate that the fuzzy decision-making mechanism of the IFSA could work properly in dynamically adapting the search behavior of the algorithm with the governing condition of the current problem. Consequently, the promising gained results reveal that IFSA can effectively be applied in solving the structural optimization problems with discrete search domains.

An integrated particle swarm optimizer for optimization of truss structures with discrete variables

Ali Mortazavi,Vedat Toğan,Ayhan Nuhoğlu 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.61 No.3

This study presents a particle swarm optimization algorithm integrated with weighted particle concept and improved fly-back technique. The rationale behind this integration is to utilize the affirmative properties of these new terms to improve the search capability of the standard particle swarm optimizer. Improved fly-back technique introduced in this study can be a proper alternative for widely used penalty functions to handle existing constraints. This technique emphasizes the role of the weighted particle on escaping from trapping into local optimum(s) by utilizing a recursive procedure. On the other hand, it guaranties the feasibility of the final solution by rejecting infeasible solutions throughout the optimization process. Additionally, in contrast with penalty method, the improved fly-back technique does not contain any adjustable terms, thus it does not inflict any extra ad hoc parameters to the main optimizer algorithm. The improved fly-back approach, as independent unit, can easily be integrated with other optimizers to handle the constraints. Consequently, to evaluate the performance of the proposed method on solving the truss weight minimization problems with discrete variables, several benchmark examples taken from the technical literature are examined using the presented method. The results obtained are comparatively reported through proper graphs and tables. Based on the results acquired in this study, it can be stated that the proposed method (integrated particle swarm optimizer, iPSO) is competitive with other metaheuristic algorithms in solving this class of truss optimization problems.

Effects of High White and Brown Sugar Consumption on Serum Level of Brain-Derived Neurotrophic Factor, Insulin Resistance, and Body Weight in Albino Rats

Ali Shamsi-Goushki,Zinat Mortazavi,Mohammad Ali Mirshekar,Fatemeh Behrasi,Nasroallah Moradi-Kor,Rasul Taghvaeefar 대한비만학회 2020 The Korean journal of obesity Vol.29 No.4

Background: In recent decades, consumption of simple sugars has increased dramatically, which contributes to health problems including insulin resistance and obesity. In this study, we investigated the effects of high concentrations of white sugar (WS) and brown sugar (BS) on serum concentration of brain-derived neurotrophic factor (BDNF), insulin resistance, and body weight in albino rats. Methods: Twenty-four male Wistar rats were randomly divided into three groups: control, a group treated with 15% WS, and a group treated with 15% BS. Rats were given WS and BS by gavage (daily) for 42 days. At the end of the intervention period, serum level of BDNF, insulin resistance, and body weight were measured. Results: Body weight and insulin resistance were significantly increased and serum BDNF level was decreased in both WS and BS groups compared to the control group (P<0.05). In the WS-treated rats, the amount of changes in the insulin resistance, body weight, and serum BDNF level was greater compared to that in BS-treated (P< 0.05). Conclusion: Due to the adverse effects of consuming high levels of WS and BS on serum level of BDNF, insulin resistance, and body weight, high intakes of these sweeteners are not recommended.

Human parvovirus B19 in patients with beta thalassemia major from Tehran, Iran

Seyed Ali Mohammad Arabzadeh,Farideh Alizadeh,Ahmad Tavakoli,Hamidreza Mollaei,Farah Bokharaei-Salim,Gharib Karimi,Mohammad Farahmand,Helya Sadat Mortazavi,Seyed Hamidreza Monavari 대한혈액학회 2017 Blood Research Vol.52 No.1

Background: Due to the tropism of human parvovirus B19 to erythroid progenitor cells, infection in patients with an underlying hemolytic disorder such as beta-thalassemia major leads to suppression of erythrocyte formation, referred to as transient aplasia crisis (TAC), which may be life-threatening. We investigated the prevalence of parvovirus B19 among patients with beta thalassemia major attending the Zafar Adult Thalassemia Clinic in Tehran, Iran. Methods: This cross-sectional study was performed to determine the presence of parvovirus B19 DNA in blood samples and parvovirus B19 genotypes in plasma samples of patients with thalassemia major. The population consisted of 150 patients with beta-thalassemia major who attended the Zafar clinic in Tehran. Specimens were studied using a real-time poly-merase chain reaction assay. Results: The prevalence of parvovirus B19 in our study population was 4%. Of 150 patients with thalassemia, six (4%) were positive for B19 DNA. There was no significant correlation between blood transfusion frequency and B19 DNA positivity. Finally, phylogenetic analy-sis of human parvovirus B19 revealed genotype I in these six patients. Conclusion: In this study, acute B19 infections were detected in patients with beta thalassemia major. Screening of such high-risk groups can considerably reduce the incidence and prevalence of B19 infection; thus, screening is required for epidemiologic surveillance and dis-ease-prevention measures.

Human parvovirus B19 in patients with beta thalassemia major from Tehran, Iran

Seyed Ali Mohammad Arabzadeh,Farideh Alizadeh,Ahmad Tavakoli,Hamidreza Mollaei,Farah Bokharaei-Salim,Gharib Karimi,Mohammad Farahmand,Helya Sadat Mortazavi,Seyed Hamidreza Monavari 대한혈액학회 2017 Blood Research Vol.52 No.1

Background: Due to the tropism of human parvovirus B19 to erythroid progenitor cells, infection in patients with an underlying hemolytic disorder such as beta-thalassemia major leads to suppression of erythrocyte formation, referred to as transient aplasia crisis (TAC), which may be life-threatening. We investigated the prevalence of parvovirus B19 among patients with beta thalassemia major attending the Zafar Adult Thalassemia Clinic in Tehran, Iran. Methods: This cross-sectional study was performed to determine the presence of parvovirus B19 DNA in blood samples and parvovirus B19 genotypes in plasma samples of patients with thalassemia major. The population consisted of 150 patients with beta-thalassemia major who attended the Zafar clinic in Tehran. Specimens were studied using a real-time poly-merase chain reaction assay. Results: The prevalence of parvovirus B19 in our study population was 4%. Of 150 patients with thalassemia, six (4%) were positive for B19 DNA. There was no significant correlation between blood transfusion frequency and B19 DNA positivity. Finally, phylogenetic analy-sis of human parvovirus B19 revealed genotype I in these six patients. Conclusion: In this study, acute B19 infections were detected in patients with beta thalassemia major. Screening of such high-risk groups can considerably reduce the incidence and prevalence of B19 infection; thus, screening is required for epidemiologic surveillance and dis-ease-prevention measures.

The effect of ultrasound in combination with thermal treatment on the germinated barley’s alpha-amylase activity

Maryam Yaldagard,Seyed.Ali. Mortazavi,Farideh. Tabatabaie 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.3

The effects of ultrasound as emerging technology along with thermal treatment were investigated on the activity of barley’s alpha-amylase after germination. All experiments were carried out at 20 kHz on an ultrasonic generator by considering the three effective factors, temperature (30, 50 and 70 oC) and ultrasonic intensities (20, 60 and 100% setting from total power of device (460 W)) in different time intervals (5, 10 and 15 min). For determining the effects of these parameters, the enzymatic activity was assayed by measuring the reducing sugars released as a result of the alpha-amylase action on soluble starch using 3,5-dinitrosalicylate regent (DNS). The results of these assays were analyzed by Qualitek4 software by using the Taguchi statistical method to evaluate the factor’s effects on the enzyme activity. Consequently, the results of assays showed that the activity of this enzyme from germinated barley was reduced after thermosonication by comparing to the blank.

Optimization of Ultrasound-assisted Extraction of Phenolic Compounds from Yarrow (Achillea beibrestinii) by Response Surface Methodology

Davoud Salar Bashi,Seyyed Ali Mortazavi,Karamatollah Rezaei,Ahmad Rajaei,Mohamad Mahdi Karimkhani 한국식품과학회 2012 Food Science and Biotechnology Vol.21 No.4

An efficient ultrasound-assisted extraction (UAE)technique was applied to extract total phenolic content (TPC) from yarrow (Achillea beibrestinii). A response surface methodology was employed to evaluate the effects of 4 independent variables (temperature, pH, solvent to sample ratio, and time) on the TPC. The optimum extraction conditions were as follows: liquid to solid ratio 20, pH 6.3, extraction temperature 35oC, and extraction time 35 min. Under the above-mentioned conditions, the experimental TPC was 11.7 mg gallic acid equivalent/g dry matter. EC50 of the UAE extract at optimal conditions was found at 30.6±0.6 mg/L level and total flavonoids (TF)were obtained at 12.6±0.2 mg/10 g sample. Also, the results of HPLC analysis showed that gallic acid and pcoumaric acid were the predominant phenolic compounds in the plant.

Apple – biomorphic synthesis of porous ZnO nanostructures for glucose direct electrochemical biosensor

Hengameh Fatemi,Abbas Ali Khodadadi,Azam Anaraki Firooz,Yadollah Mortazavi 한국물리학회 2012 Current Applied Physics Vol.12 No.4

Biomorphic porous ZnO nanostructures were successfully synthesized via an aqueous solegel soaking process using pieces of apple flesh and skin as templates and employed for glucose direct electrochemical biosensor. The structure and morphology of ZnO nanostructures were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). By modifying glassy carbon electrode with the biomorphic ZnO nanostructures and Nafion, two glucose biosensors were constructed and their direct electrochemistry of glucose oxidase (GOD) was successfully investigated by cyclic voltammetry (CV). The biomorphic porous ZnO nanostructures using apple skin template (S-ZnO) were more effective in facilitating the electron transfer of immobilized GOD than that of using flesh apple template (F-ZnO). This may be a result of the unique morphology and smaller average crystallite size of the S-ZnO nanostructure. GOD immobilized on Nafion-porous S-ZnO nanostructure composite display direct, reversible,and surface-controlled redox reaction with a detection limit of 10 mM, a response time of 7 s, high sensitivity of 23.4 mA/mM cm2 and a fast heterogeneous electron transfer rate with a rate constant (ks) of 3.9 s-1. It was found that S-ZnO significantly has improved the direct electron transfer between GOD and glassy carbon electrode with good stability and reproducibility. Biomorphic porous ZnO nanostructures were successfully synthesized via an aqueous solegel soaking process using pieces of apple flesh and skin as templates and employed for glucose direct electrochemical biosensor. The structure and morphology of ZnO nanostructures were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). By modifying glassy carbon electrode with the biomorphic ZnO nanostructures and Nafion, two glucose biosensors were constructed and their direct electrochemistry of glucose oxidase (GOD) was successfully investigated by cyclic voltammetry (CV). The biomorphic porous ZnO nanostructures using apple skin template (S-ZnO) were more effective in facilitating the electron transfer of immobilized GOD than that of using flesh apple template (F-ZnO). This may be a result of the unique morphology and smaller average crystallite size of the S-ZnO nanostructure. GOD immobilized on Nafion-porous S-ZnO nanostructure composite display direct, reversible,and surface-controlled redox reaction with a detection limit of 10 mM, a response time of 7 s, high sensitivity of 23.4 mA/mM cm2 and a fast heterogeneous electron transfer rate with a rate constant (ks) of 3.9 s-1. It was found that S-ZnO significantly has improved the direct electron transfer between GOD and glassy carbon electrode with good stability and reproducibility.

Comparative model analysis of the performance of tube fitted bulk monolithic catalyst with conventional pellet shapes for natural gas reforming

Akbar Zamaniyan,Yadollah Mortazavi,Hossein Manafi,Abbas Ali Khodadadi 한국공업화학회 2011 Journal of Industrial and Engineering Chemistry Vol.17 No.4

A novel catalyst shape for reforming reaction, as an intraparticle diffusion limited-reaction, using bulk monolithic catalyst (BMC), the so-called tube fitted bulk monolithic catalyst (TFBMC), instead of conventional pellets is presented. A detailed analysis of the transport phenomena and proper models are introduced. The model is applied for natural gas reforming reaction and validated using industrial data. Then comparative model analysis and comparison for packed bed rector using conventional pellet shapes and TFBMC is presented. The results indicate that the TFBMC has superior advantages over the conventional pellet shapes especially with regards to the pressure drop and effective usage of the catalyst. Thus, TFBMC offer smaller reactor volume for processing similar feed flow which in turn results in less capital cost and also energy saving in the course of operation. Moreover, the TFBMC concept may be easily adapted to the present fixed bed reactors which use conventional pellet catalysts resulting more productivity and better performance.