High-precision modeling of uplift capacity of suction caissons using a hybrid computational method

Alavi, Amir Hossein,Gandomi, Amir Hossein,Mousavi, Mehdi,Mollahasani, Ali Techno-Press 2010 Geomechanics & engineering Vol.2 No.4

A new prediction model is derived for the uplift capacity of suction caissons using a hybrid method coupling genetic programming (GP) and simulated annealing (SA), called GP/SA. The predictor variables included in the analysis are the aspect ratio of caisson, shear strength of clayey soil, load point of application, load inclination angle, soil permeability, and loading rate. The proposed model is developed based on well established and widely dispersed experimental results gathered from the literature. To verify the applicability of the proposed model, it is employed to estimate the uplift capacity of parts of the test results that are not included in the modeling process. Traditional GP and multiple regression analyses are performed to benchmark the derived model. The external validation of the GP/SA and GP models was further verified using several statistical criteria recommended by researchers. Contributions of the parameters affecting the uplift capacity are evaluated through a sensitivity analysis. A subsequent parametric analysis is carried out and the obtained trends are confirmed with some previous studies. Based on the results, the GP/SA-based solution is effectively capable of estimating the horizontal, vertical and inclined uplift capacity of suction caissons. Furthermore, the GP/SA model provides a better prediction performance than the GP, regression and different models found in the literature. The proposed simplified formulation can reliably be employed for the pre-design of suction caissons. It may be also used as a quick check on solutions developed by more time consuming and in-depth deterministic analyses.

Analytical solution for analyzing initial curvature effect on vibrational behavior of PM beams integrated with FGP layers based on trigonometric theories

Mousavi, S. Behnam,Amir, Saeed,Jafari, Akbar,Arshid, Ehsan Techno-Press 2021 Advances in nano research Vol.10 No.3

In the current study, the free vibrational behavior of a Porous Micro (PM) beam which is integrated with Functionally Graded Piezoelectric (FGP) layers with initial curvature is considered based on the two trigonometric shear deformation theories namely SSDBT and Tan-SDBT. The structure's mechanical properties are varied through its thicknesses following the given functions. The curved microbeam is exposed to electro-mechanical preload and also is rested on a Pasternak type of elastic foundation. Hamilton's principle is used to extract the motion equations and the MCST is used to capture the size effect. Navier's solution method is selected as an analytical method to solve the motion equations for a simply supported ends case and by validating the results for a simpler state with previously published works, effects of different important parameters on the behavior of the structure are considered. It is found that although increasing the porosity reduces the natural frequency, but enhancing the volume fraction of CNTs increasing it. Also, by increasing the central angle of the curved beam the vibrations of the structure increases. Designing and manufacturing more efficient smart structures such as sensors and actuators are of the aims of this study.

Design of Nonlinear Lead and/or Lag Compensators

Amir Nassirharand,Seyed Reza Mousavi Firdeh 대한전기학회 2008 International Journal of Control, Automation, and Vol.6 No.3

A known nonlinear compensator design approach is adapted to allow design of nonlinear lead and/or lag compensators, and a number of MATLAB functions are developed that automate the compensator design procedure. With this design tool, control engineers would be able to rapidly design nonlinear lead and/or lag compensators. An example of a tutorial nature is presented.

Acoustic Noise Reduction and Power Factor Correction in Switched Reluctance Motor Drives

Amir Rashidi,Sayed Mortaza Saghaiannejad,Sayed Javad Mousavi 전력전자학회 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.1

In this paper, a four-phase 8/6-pole 4-㎾ SR motor drive model is presented. Based on experimental data, the model allows an accurate simulation of a drive in dynamic operation. Simulations are performed and a laboratory type set-up is built based on a TI TMS320F2812 platform to experimentally verify the theoretical results obtained for a SR motor. To reduce acoustic noise and to correct the power factor of this drive, a two-stage power converter is proposed that uses a current source rectifier (CSR) as the input stage for the asymmetrical converter of the studied SRM. Employing the space-vector modulation (SVM) method in matrix converters, the CSR switching allows the dc link’s capacitors to be eliminated and the power factor of the SRM drive to be improved. As the electrical motive force (emf) is directly proportional to the rotor speed, the input voltage to the machine can be programmed to be a function of the speed with the modulation index of the CSR, leading to a reduction in the acoustic noise of the SRM drive. Simulation of the whole SRM drive system is performed using MATLAB-Simulink. The results fully comply with the required conditions such as power factor correction with an improvement in the THD.

Acoustic Noise Reduction and Power Factor Correction in Switched Reluctance Motor Drives

Rashidi, Amir,Saghaiannejad, Sayed Mortaza,Mousavi, Sayed Javad The Korean Institute of Power Electronics 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.1

In this paper, a four-phase 8/6-pole 4-kW SR motor drive model is presented. Based on experimental data, the model allows an accurate simulation of a drive in dynamic operation. Simulations are performed and a laboratory type set-up is built based on a TI TMS320F2812 platform to experimentally verify the theoretical results obtained for a SR motor. To reduce acoustic noise and to correct the power factor of this drive, a two-stage power converter is proposed that uses a current source rectifier (CSR) as the input stage for the asymmetrical converter of the studied SRM. Employing the space-vector modulation (SVM) method in matrix converters, the CSR switching allows the dc link's capacitors to be eliminated and the power factor of the SRM drive to be improved. As the electrical motive force (emf) is directly proportional to the rotor speed, the input voltage to the machine can be programmed to be a function of the speed with the modulation index of the CSR, leading to a reduction in the acoustic noise of the SRM drive. Simulation of the whole SRM drive system is performed using MATLAB-Simulink. The results fully comply with the required conditions such as power factor correction with an improvement in the THD.

Immunogenicity of EIT chimeric protein expressed in transplastomic tobacco plants towards development of an oral vaccine against Escherichia coli O157:H7

Farrokh Karimi,Amir Mousavi,Houshang Alizadeh,Ali Hatef Salmanian,Sima Rafati 한국식물생명공학회 2013 Plant biotechnology reports Vol.7 No.4

Chloroplast genetic engineering offers an opportunity for high level expression and cost-effective recombinant protein production. Escherichia coli O157:H7 is one of the most important zoonotic pathogens causing hemorrhagic colitis (HC) and the life-threatening hemolytic- uremic syndrome in humans worldwide. The occurrence of zoonotic E. coli O157:H7 outbreaks in recent years has led to increased efforts in the development of safe and cost-effective immunogenic antigens against E. coli O157:H7. EspA and Tir/Intimin proteins are the important virulence factors which are encoded by the LEE locus of enterohemorrhagic E. coli. In this study, we hypothesized that the high level expression of the chimeric form of these effectors in chloroplasts and using tobacco transplastomic plants as an oral delivery system for the development of an edible-base vaccine would induce an immune response for the prevention of E. coli 0157:H7 attachment and colonization in animal model mice. The prokaryotic codonoptimizedEIT protein was expressed in plastid genome via chloroplast transformation. Putative transplastomic plants were analyzed by PCR, and Southern blot analysis confirmingchloroplast integration and homoplasmy in the T1 progeny. Immunoblotting and ELISA assays demonstrated that the EIT protein was expressed in chloroplasts and accumulated up to 1.4 % of total soluble protein in leaf tissue. In mice orally immunized with transplastomic tobacco plant leaves, high immunological responses (IgG and IgA specific antibodies) were detected in serum and feces. Finally, the challenging assay with E. coli O157:H7 in immunized mice showed reduced bacterial shedding.

Immunogenicity of EIT chimeric protein expressed in transplastomic tobacco plants towards development of an oral vaccine against Escherichia coli O157:H7

Karimi, Farrokh,Mousavi, Amir,Salmanian, Ali Hatef,Alizadeh, Houshang,Rafati, Sima 한국식물생명공학회 2013 Plant biotechnology reports Vol.7 No.4

Chloroplast genetic engineering offers an opportunity for high level expression and cost-effective recombinant protein production. Escherichia coli O157:H7 is one of the most important zoonotic pathogens causing hemorrhagic colitis (HC) and the life-threatening hemolytic-uremic syndrome in humans worldwide. The occurrence of zoonotic E. coli O157:H7 outbreaks in recent years has led to increased efforts in the development of safe and cost-effective immunogenic antigens against E. coli O157:H7. EspA and Tir/Intimin proteins are the important virulence factors which are encoded by the LEE locus of enterohemorrhagic E. coli. In this study, we hypothesized that the high level expression of the chimeric form of these effectors in chloroplasts and using tobacco transplastomic plants as an oral delivery system for the development of an edible-base vaccine would induce an immune response for the prevention of E. coli 0157:H7 attachment and colonization in animal model mice. The prokaryotic codonoptimized EIT protein was expressed in plastid genome via chloroplast transformation. Putative transplastomic plants were analyzed by PCR, and Southern blot analysis confirming chloroplast integration and homoplasmy in the T1 progeny. Immunoblotting and ELISA assays demonstrated that the EIT protein was expressed in chloroplasts and accumulated up to 1.4 % of total soluble protein in leaf tissue. In mice orally immunized with transplastomic tobacco plant leaves, high immunological responses (IgG and IgA specific antibodies) were detected in serum and feces. Finally, the challenging assay with E. coli O157:H7 in immunized mice showed reduced bacterial shedding.

Assessment of hemolytic activity of bee venom against some physicochemical factors

Yaser Yousefpoor,Amir Amani,Adeleh Divsalar,Seyyedeh Elaheh Mousavi,Yaser Eskandari Torbaghan,Omid Emami 한국응용곤충학회 2019 Journal of Asia-Pacific Entomology Vol.22 No.4

Bee venom (BV) is a biotoxin with biologically active peptides which have cell lysis and hemolytic activity properties. These properties can be affected under different storage conditions or during the production process. In present study, we investigated effects of a number of physicochemical factors, including temperature, pH, UV radiation, ultrasound waves and storage time on hemolytic activity of BV. Maximum absorption and melting temperature of BV solution were obtained as 280 nm and ~70 °C, respectively. Cell hemolysis 50 (CH 50 ) -concentration of BV that can lyse 50% of red blood cells- was determined as 0.94 μg/ml at ambient temperature. CH 50 was shown not to be importantly varied at temperature up to 60 °C, pH value 2 to 13 and under UV/ ultrasound radiation. Storage at −20, 6 and 25 °C for 6 months made about 2.5, 35 and 1000 times increase in CH 50 . From the results, it may be concluded that BV is a relatively resistant hemolytic agent and can be used in a variety of laboratory research and product manufacturing methods.

Ce-oxide quantum dots decorated graphene oxide (CeO-QDs-GO) nano-platforms synthesis and application in epoxy matrix for efficient anti-corrosion ability

M.H. Shahini,Maryam Mousavi,Amir Masoud Arabi,Mohammad Mahdavian,Bahram Ramezanzadeh 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.101 No.-

In this endeavor, ultra-fine Ce oxide QDs were synthesized via an in-situ approach which itself wasdivided into two methods exploited to synthesize QDs on the GO nanosheets. Afterward, the obtainedproduct was loaded into the Epoxy (EP) structure and finally applied on the surface. The results affirmedthe presence of Ce oxide QDs and the quantum confinement effect in both samples. FT-IR analysis confirmedthe presence of different functional groups such as C@C and CAH. UV–Vis outcome showed theinteraction of GO nanosheets and CeO2 QDs. The morphology of the surface, QDs distribution on theGO nanosheets, shape, and particle sizes were explored using FESEM and HR-TEM. Lastly, the corrosionsuppression of different coatings—pure EP, GO-only-containing EP, or EP loaded with quantum-dotsdepositedGO synthesized by two methods—were compared and discussed in detail with the help ofEIS and salt spray methods. The result showed that, in the scratched samples, the maximum Rct of45,080 ohm.cm2 was reached when the QDs-modified GO, attaining via the first method, was employed. The overall result denoted the superior performance of the QDs-modified GO nanosheets embedded inthe EP coating—most specifically the one synthesized with the first method.

Risk Factors for Post-ERCP Cholangitis in Patients with Pancreatic Cancer from a Single Referral Center in Iran

Salehimarzijarani, Babak,Dadvar, Zohreh,Mousavi, Mirhadi,Mirsattari, Dariush,Zali, Mohammad Reza,Alizadeh, Amir Houshang Mohammad Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.4

Cholangitis is relatively uncommon but associated mortality is high due to the predisposition in people with underlying disease. For this recognition of contributing risk factors is necessary. Therefore, the present descriptive-analytical cross-sectional survey was designed to determine contributing risk factors for post-ERCP cholangitis in patients with pancreatic cancer. From 2005 to 2010, 110 consecutive cases of pancreatic cancer attending to a tertiary referral centre (Taleghani Hospital), Tehran, Iran were recruited. The patients all underwent stenting via endoscopic retrograde cholangiopancreatography (ERCP). On univariate analysis, a metallic stent type (95% confidence interval (CI) 1.025-11.34, P=0.037), having no jaundice (1.44-2.22, P=0.009), having no pain (1.32-1.91, P=0.026), a history of prior ERCP (1.16-10.37, P=0.020), and having a proximal biliary stone (1.002-5.93, P=0.046) were related to cholangitis. However on multivariate analysis, none of these factors were found to be contributing risk factors. Cholangitis is avoidable with adequate biliary drainage. Because success rates are higher and complication rates lower for endoscopists performing large volumes of ERCP, performance of the procedure should be concentrated as much as possible in institutions with endoscopists having adequate experience. Patients with a high risk for complications may be best served by referral to an advanced center.