A modified particle swarm approach for multi-objective optimization of laminated composite structures

Sepehri, A.,Daneshmand, F.,Jafarpur, K. Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.42 No.3

Particle Swarm Optimization (PSO) is a stochastic population based optimization algorithm which has attracted attentions of many researchers. This method has great potentials to be applied to many optimization problems. Despite its robustness the standard version of PSO has some drawbacks that may reduce its performance in optimization of complex structures such as laminated composites. In this paper by suggesting a new variation scheme for acceleration parameters and inertial weight factors of PSO a novel optimization algorithm is developed to enhance the basic version's performance in optimization of laminated composite structures. To verify the performance of the new proposed method, it is applied in two multi-objective design optimization problems of laminated cylindrical. The numerical results from the proposed method are compared with those from two other conventional versions of PSO-based algorithms. The convergancy of the new algorithms is also compared with the other two versions. The results reveal that the new modifications inthe basic forms of particle swarm optimization method can increase its convergence speed and evade it from local optima traps. It is shown that the parameter variation scheme as presented in this paper is successful and can evenfind more preferable optimum results in design of laminated composite structures.

Optimization in measurement of MVC and active stiffness in wrist using the quick release method

Behrooz Sepehri,Asghar Soltani- Mirzaee 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.9

The quick release method was used for measurement of Biomechanical parameters in the wrist joints. Wrist joint was previously studiedin many researches for its biomechanical characteristics. However, more automation in measurement process has been discussed. Inthis research, a new test rig with a specified control unit was fabricated. Measurement of parameters in few seconds after the release wasconsidered in the design of the new test rig. Based on reliability tests performed, the fabricated test rig showed firmly reliable measurementsfor maximum voluntary contraction, and active stiffness. These were true for both cases of left and right wrists during flexion andextension.

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.

A modified particle swarm approach for multi-objective optimization of laminated composite structures

A. Sepehri,F. Daneshmand,K. Jafarpur 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.42 No.3

Particle Swarm Optimization (PSO) is a stochastic population based optimization algorithm which has attracted attentions of many researchers. This method has great potentials to be applied to many optimization problems. Despite its robustness the standard version of PSO has some drawbacks that may reduce its performance in optimization of complex structures such as laminated composites. In this paper by suggesting a new variation scheme for acceleration parameters and inertial weight factors of PSO a novel optimization algorithm is developed to enhance the basic version’s performance in optimization of laminated composite structures. To verify the performance of the new proposed method, it is applied in two multi-objective design optimization problems of laminated cylindrical. The numerical results from the proposed method are compared with those from two other conventional versions of PSObased algorithms. The convergancy of the new algorithms is also compared with the other two versions. The results reveal that the new modifications inthe basic forms of particle swarm optimization method can increase its convergence speed and evade it from local optima traps. It is shown that the parameter variation scheme as presented in this paper is successful and can evenfind more preferable optimum results in design of laminated composite structures.

Pectic-Oligoshaccharides from Apples Induce Apoptosis and Cell Cycle Arrest in MDA-MB-231 Cells, a Model of Human Breast Cancer

Delphi, Ladan,Sepehri, Houri,Khorramizadeh, Mohammad Reza,Mansoori, Fatemeh Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.13

Background: The effects of plant products on cancer cells has become a field of major importance. Many substancesmay induce apoptosis in anti-cancer treatment. Pectins, a family of complex polysaccharides, and their degradation products may for exasmple exert apoptotic effects in cancer cells. Apples and citrus fruits are the main sources of pectin which can be applied for anti-cancer research. The present study concerned an intact form of pectic-oligoshaccharide named pectic acid (poly galactronic acid). Materials and Methods: Inhibition of cell proliferation assays (MTT), light microscopy, fluorescence microscopy (acridin orange/ethidium bromide), DNA fragmentation tests, cell cycle analysis, annexin PI and Western blotting methods were applied to evaluate apoptosis. Results: The results indicated that pectic acid inhibited cell growth and reduced cell attachment after 24h incubation. This did not appear to be due to necrosis, since morphological features of apoptosis were detected with AO/EB staining and cell cycling was blocked in the sub-G1 phase. Annexin/PI and DNA fragmentation findings indicated that apoptosis frequency increased after 24h incubation with pectic acid. In addition, the data showed pectic acid induced caspase-dependent apoptosis. Conclusions: These data indicate that apple pectic acid without any modification could trigger apoptosis in MDA-MB-231 human breast cancer cells and has potential to improve cancer treatment as a natural product.

Root cause detection of leakage in check valves using multi-scale signal analysis

Chengbiao Tong,Nariman Sepehri,Jiang Zhou 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.1

Check valves are key components required to ensure that fluid flows in one direction. Internal cross-port leakage is a common fault that affects the service performance of check valves. Cross-port leakage occurs due to defects in the valve spool. Early detection of this fault and its root cause is important to prevent downtime and subsequent costs. This research presents a multi-scale signal enhancement method based on spool impact and pressure signal analysis for leakage identification and its root causes. The impact signals obtained by accelerometers attached to the valve body are segmented from the entire vibration signal to capture the variations in the inherent characteristics of the valve. Subsequently, wavelet packet decomposition and reconstruction are performed to extract the energy distribution and energy entropy of signals. The time-frequency domain is used to extract features for leakage identification faults. Correlation analysis was applied to select 45 sensitive features out of 105 features. The performance of the method was verified using the RCYCS-G experimental hydraulic platform, and the recognition rate of four modes was found to be 100 % accurate. The proposed method accurately identifies the root causes of leakage in the check valve, lays a foundation for leakage rate prediction, and has significant engineering application value in predictive maintenance.

Incidence and Mortality of Colorectal Cancer and Relationships with the Human Development Index across the World

Rafiemanesh, Hosein,Mohammadian-Hafshejani, Abdollah,Ghoncheh, Mahshid,Sepehri, Zahra,Shamlou, Reza,Salehiniya, Hamid,Towhidi, Farhad,Makhsosi, Behnam Reza Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.5

Background: This study aimed to investigate the standardized incidence and mortality rate of colorectal cancer and its relationship with the human development index (HDI) across the world in 2012. Materials and Methods: This ecologic study was conducted for assessment of the correlation between age-specific incidence rate (ASIR) and age-specific mortality rate (ASMR) with HDI and its components. Data for SIR and SMR for every country for the year 2012 were obtained from the global cancer project. We used a bivariate method for assessment of the correlation between SIR and SMR and HDI. Statistical significance was assumed at P<0.05. Statistical analyses were performed using SPSS (Version 22.0, SPSS Inc.). Results: Countries with the highest SIR of colorectal cancer in the world in 2012, were Republic of Korea, Slovakia, Hungary and countries with the highest SMR were Hungary, Croatia and Slovakia. The correlation between SIR of colorectal cancer and the HDI was 0.712 ($P{\leq}0.001$), with life expectancy at birth 0.513 ($P{\leq}0.001$), with mean years of schooling 0.641 ($P{\leq}0.001$) and with level of income per each person of the population 0.514 (P=0.013). In addition, the correlation between SMR of colorectal cancer and the HDI was 0.628 ($P{\leq}0.001$), with life expectancy at birth 0.469 ($P{\leq}0.001$), with mean years of schooling 0.592 ($P{\leq}0.001$) and with level of income per each person of the population 0.378 (P=0.013). Conclusions: The highest SIR and SMR of colorectal cancer was in the WHO Europe region. There was a positive correlation between HDI and SIR and SMR of colorectal cancer.

Active Disturbance Rejection Control Applied to High-order Systems with Parametric Uncertainties

Zhengrong Chu,Christine Wu,Nariman Sepehri 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.6

Active disturbance rejection control (ADRC) is an emerging control technique known for its simplicity and good disturbance rejection ability. It has been applied to first- and second-order systems in many areas. However, the application of the ADRC to high-order systems is few and also challenging because the existing bandwidth tuning method is unable to determine proper controller parameters to achieve desired system performance. To address this problem, a new method is proposed to tune the ADRC for controlling high-order systems. First, the ADRC is decomposed into a controller and a prefilter in the frequency domain. Second, they are tuned to satisfy prescribed performance specifications. Two applications of the ADRC to high-order hydraulic systems are presented. It is shown that the proposed method greatly improves the performance of the ADRC compared to the bandwidth tuning method.

The Effects of Probiotic Lactobacillus and Bifidobacterium Strains on Memory and Learning Behavior, Long-Term Potentiation (LTP), and Some Biochemical Parameters in β-Amyloid-Induced Rat’s Model of Alzheimer’s Disease

Zahra Rezaeiasl,Mahmoud Salami,Gholamreza Sepehri 한국식품영양과학회 2019 Preventive Nutrition and Food Science Vol.24 No.3

This study assessed the effects of probiotic supplementation on spatial learning and memory, long-term potentiation (LTP), paired-pulse facilitation (PPF) ratios, nitric oxide (NO) concentrations, and lipid profiles in a rat model of amyloid beta (Aβ)(1-42)-induced Alzheimer’s disease (AD). Forty rats were randomly divided into 4 groups. The sham (control and prevention) group received intracerebroventricular (ICV) injections of artificial cerebrospinal fluid, the Alzheimer group received ICV injection of Aβ(1-42), and the probiotic+Alzheimer group received 500 mg probiotics daily (15 ×10<SUP>9</SUP> colony-forming unit) by gavage for 4 weeks before and 2 weeks after injection of Aβ(1-42). The Morris water maze test was performed for evaluation of spatial learning and memory. LTP and PPF ratios were measured to evaluate longterm synaptic plasticity and pre-synaptic mechanisms, respectively. The results showed that probiotic supplementation significantly improved learning, but not memory impairment, and increased PPF ratios compared to those in the Alzheimer group. Both Aβ(1-42) injection and probiotic supplementation alone did not significantly effect plasma level of NO. Probiotic supplementation of rats in the probiotic (6 weeks)+Alzheimer group decreased serum levels of total cholesterol, triglyceride, and very low-density lipoprotein-cholesterol significantly compared to the Alzheimer group. The results of this study suggest that probiotic supplementation may positively impact learning capacity and LTP in rats with AD, most likely via the release of neurotransmitters via presynaptic mechanisms or via a protective effect on serum lipid profiles.

A Regionalization Model to Increase Equity of Access to Maternal and Neonatal Care Services in Iran

Zahra Mohammadi Daniali,Mohammad Mehdi Sepehri,Farzad Movahedi Sobhani,Mohammad Heidarzadeh 대한예방의학회 2022 예방의학회지 Vol.55 No.1

Objectives: Access to maternal and neonatal care services (MNCS) is an important goal of health policy in developing countries. In this study, we proposed a 3-level hierarchical location-allocation model to maximize the coverage of MNCS providers in Iran. Methods: First, the necessary criteria for designing an MNCS network were explored. Birth data, including gestational age and birth weight, were collected from the data bank of the Iranian Maternal and Neonatal Network national registry based on 3 service levels (I, II, and III). Vehicular travel times between the points of demand and MNCS providers were considered. Alternative MNCS were mapped in some cities to reduce access difficulties. Results: It was found that 130, 121, and 86 MNCS providers were needed to respond to level I, II, and III demands, respectively, in 373 cities. Service level III was not available in 39 cities within the determined travel time, which led to an increased average travel time of 173 minutes to the nearest MNCS provider. Conclusions: This study revealed inequalities in the distribution of MNCS providers. Management of the distribution of MNCS providers can be used to enhance spatial access to health services and reduce the risk of neonatal mortality and morbidity. This method may provide a sustainable healthcare solution at the policy and decision-making level for regional, or even universal, healthcare networks.