Electrochemical Corrosion Behavior of Duplex Stainless SteelAISI 2205 in Ethylene Glycol-Water Mixture in the Presence of50 W/V % LiBr

Goodarzi, A.,Danaee, I.,Eskandari, H.,Nikmanesh, S. The Korean Electrochemical Society 2016 Journal of electrochemical science and technology Vol.7 No.1

The corrosion behavior of duplex stainless steel AISI 2205 was investigated in ethylene glycol-water mixture in the presence of 50 W/V % LiBr at different concentrations and different temperatures. Cyclic polarization, impedance measurements and Mott-Schottky analysis were used to study the corrosion behavior the semi conductive properties of the passive films. The results showed that with increasing in the ethylene glycol concentration to 10 V/V%, the corrosion rate of the steel alloy substrate increased. In higher concentrations of ethylene glycol, corrosion current of steel decreased. The results of scanning electron microscopy of electrode surface confirmed the electrochemical tests. Electrochemical experiment showed that duplex steel was stable for pitting corrosion in this environment. The increase in the ethylene glycol concentration led to increasing the susceptibility to pitting corrosion. The corrosion current increased as the temperature rise and also pitting potentials and repassivation potentials shifted towards the less positive values as the temperature increased. According to Mott-Schottky analysis, passive films of stainless steel at the different temperatures showed both n-type and p-type semiconductor behavior in different potential.

Geometric Adaptive Tracking Control of a Quadrotor Unmanned Aerial Vehicle on SE(3) for Agile Maneuvers

Goodarzi, Farhad A.,Lee, Daewon,Lee, Taeyoung ASME International 2015 Journal of Dynamic Systems, Measurement and Contro Vol. No.

Assessing the anion type effect on the hydro-mechanical properties of smectite from macro and micro-structure aspects

Goodarzi, Amir R.,Akbari, Hamid R. Techno-Press 2014 Geomechanics & engineering Vol.7 No.2

The expansivity of clayey soils is a complicated phenomenon which may affect the stability of geotechnical structures and geo-environmental projects. In all common factors for the monitoring of soil expansion, less attention is given to anion type of pore space solutions. Therefore, this paper is concerned with the impact of various concentrations of different inorganic salts including NaCl, $Na_2SO_4$, and $Na_2CO_3$ on the macro and microstructure behavior of the expandable smectite clay. Comparison of the responses of the smectite/NaCl and smectite/$Na_2SO_4$ mixtures indicates that the effect of anion valance on the soil engineering properties is not very pronounced, regardless of the electrolyte concentration. However, at presence of carbonate as potential determining ions (PDIs) the swelling power increases up to 1.5 times compared to sulfate or chloride ions. The samples with $Na_2CO_3$ are also more deformable and show lower osmotic compressibility than the other mixtures. This demonstrates that the barrier performance of smectite greatly decreases in case of anions with the non-specific adsorption (e.g., $Cl^-$ and $SO{_4}^{2-}$) as the salinity of solution increases. Based on the results of the X-ray diffraction and sedimentation tests, the high soil volumetric changes upon exposure to carbonate is attributed to an increase in the repulsive forces between smectite basic unit layers due to the PDI effect of $CO{_3}^{2-}$ and increasing the pH level which enhance the buffering capacity of smectite. The study concluded that the nature of anion through its influence on the re-arrangement of soil microstructure and osmotic phenomena governs the hydro-mechanical parameters of expansive clays. It seems not coinciding with the double layer theory of the Gouy-Chapman double layer model.

Innovation Network Development Model in Telemedicine: A Change in Participation

Maryam Goodarzi,Mashallah Torabi,Reza Safdari,Hossein Dargahi,Sara Naeimi 대한의료정보학회 2015 Healthcare Informatics Research Vol.21 No.4

This paper introduces a telemedicine innovation network and reports its implementation in Tehran University of Medical Sciences. The required conditions for the development of future projects in the field of telemedicine are also discussed; such projects should be based on the common needs and opportunities in the areas of healthcare, education, and technology. Methods: The development of the telemedicine innovation network in Tehran University of Medical Sciences was carried out in two phases: identifying the beneficiaries of telemedicine, and codification of the innovation network memorandum; and brainstorming of three workgroup members, and completion and clustering ideas. The present study employed a qualitative survey by using brain storming method. Thus, the ideas of the innovation network members were gathered, and by using Freeplane software, all of them were clustered and innovation projects were defined. Results: In the services workgroup, 87 and 25 ideas were confirmed in phase 1 and phase 2, respectively. In the education workgroup, 8 new programs in the areas of telemedicine, tele-education and teleconsultation were codified. In the technology workgroup, 101 and 11 ideas were registered in phase 1 and phase 2, respectively. Conclusions: Today, innovation is considered a major infrastructural element of any change or progress. Thus, the successful implementation of a telemedicine project not only needs funding, human resources, and full equipment. It also requires the use of innovation models to cover several different aspects of change and progress. The results of the study can provide a basis for the implementation of future telemedicine projects using new participatory, creative, and innovative models. Keywords: Innovation, Idea, Health Care Administrat

INTEGRATED FUZZY/OPTIMAL VEHICLE DYNAMIC CONTROL

A. GOODARZI,M. ALIREZAIE 한국자동차공학회 2009 International journal of automotive technology Vol.10 No.5

There are basically two methods to control yaw moment which is the most efficient way to improve vehicle stability and handling. The first method is indirect yaw moment control, which works based on control of the lateral tire force through steering angle control. It is mainly known as active steering control (ASC). Nowadays, the most practical approach to steering control is active front steering (AFS). The other method is direct yaw moment control (DYC), in which an unequal distribution of longitudinal tire forces (mainly braking forces) produces a compensating external yaw moment. It is well known that the AFS performance is limited in the non-linear vehicle handling region. On the other hand, in spite of a good performance of DYC in both the linear and non-linear vehicle handling regions, continued DYC activation could lead to uncomfortable driving conditions and an increase in the stopping distance in the case of emergency braking. It is recommended that DYC be used only in high-g critical maneuvers. In this paper, an integrated fuzzy/optimal AFS/DYC controller has been designed. The control system includes five individual optimal LQR control strategies; each one, has been designed for a specific driving condition. The strategies can cover low, medium, and high lateral acceleration maneuvers on high-μ or low-μ roads. A fuzzy blending logic also has been utilized to mange each LQR control strategy contribution level in the final control action. The simulation results show the advantages of the proposed control system over the individual AFS or DYC controllers. There are basically two methods to control yaw moment which is the most efficient way to improve vehicle stability and handling. The first method is indirect yaw moment control, which works based on control of the lateral tire force through steering angle control. It is mainly known as active steering control (ASC). Nowadays, the most practical approach to steering control is active front steering (AFS). The other method is direct yaw moment control (DYC), in which an unequal distribution of longitudinal tire forces (mainly braking forces) produces a compensating external yaw moment. It is well known that the AFS performance is limited in the non-linear vehicle handling region. On the other hand, in spite of a good performance of DYC in both the linear and non-linear vehicle handling regions, continued DYC activation could lead to uncomfortable driving conditions and an increase in the stopping distance in the case of emergency braking. It is recommended that DYC be used only in high-g critical maneuvers. In this paper, an integrated fuzzy/optimal AFS/DYC controller has been designed. The control system includes five individual optimal LQR control strategies; each one, has been designed for a specific driving condition. The strategies can cover low, medium, and high lateral acceleration maneuvers on high-μ or low-μ roads. A fuzzy blending logic also has been utilized to mange each LQR control strategy contribution level in the final control action. The simulation results show the advantages of the proposed control system over the individual AFS or DYC controllers.

Prevalence of iron deficiency anemia in Asian female population and human development index (HDI): an ecological study

( Elham Goodarzi ),( Reza Beiranvand ),( Hasan Naemi ),( Isan Darvishi ),( Zaher Khazaei ) 대한산부인과학회 2020 Obstetrics & Gynecology Science Vol.63 No.4

Objective Anemia is a major problem in developing countries, the purpose of the present study was to investigate the relationship between the human development index (HDI) and the prevalence of anemia among Asian women. Methods This was a descriptive-analytic ecological study. The study analyzed data including HDI and prevalence of anemia extracted from the World Bank. The correlation coefficient and analysis of variance were used for data analysis. The significance level was considered to be less than 0.05. Analyses were performed using Stata-14 software. Results The results revealed that the prevalence of anemia in women of reproductive age (R=-0.626, P<0.001), pregnant women (R=-0.576, P<0.001) and non-pregnant women (R=-0.623, P<0.0001) was significantly negatively correlated with HDI index. In the analysis of HDI components and the prevalence of anemia, a significant negative correlation was observed between the prevalence of anemia and the mean years of schooling, life expectancy at birth, and expected years of schooling indices in all 3 groups of women (non-pregnant, pregnant, and of reproductive age) (P<0.05). Conclusion Since there was a negative correlation between the prevalence of anemia in women and HDI, paying greater attention to factors which influence anemia may contribute to the prevention of anemia in developing countries.

Preparation and Characterization of Nanocomposite Scaffolds (Collagen/β-TCP/SrO) for Bone Tissue Engineering

Hamid Goodarzi,Sameereh Hashemi-Najafabadi,Nafiseh Baheiraei,Fatemeh Bagheri 한국조직공학과 재생의학회 2019 조직공학과 재생의학 Vol.16 No.3

BACKGROUND: Nowadays, production of nanocomposite scaffolds based on natural biopolymer, bioceramic, and metal ions is a growing field of research due to the potential for bone tissue engineering applications. METHODS: In this study, a nanocomposite scaffold for bone tissue engineering was successfully prepared using collagen (COL), beta-tricalcium phosphate (b-TCP) and strontium oxide (SrO). A composition of b-TCP (4.9 g) was prepared by doping with SrO (0.05 g). Biocompatible porous nanocomposite scaffolds were prepared by freeze-drying in different formulations [COL, COL/b-TCP (1:2 w/w), and COL/b-TCP-Sr (1:2 w/w)] to be used as a provisional matrix or scaffold for bone tissue engineering. The nanoparticles were characterized by X-ray diffraction, Fourier transforms infrared spectroscopy and energy dispersive spectroscopy. Moreover, the prepared scaffolds were characterized by physicochemical properties, such as porosity, swelling ratio, biodegradation, mechanical properties, and biomineralization. RESULTS: All the scaffolds had a microporous structure with high porosity (* 95–99%) and appropriate pore size (100–200 lm). COL/b-TCP-Sr scaffolds had the compressive modulus (213.44 ± 0.47 kPa) higher than that of COL/b- TCP (33.14 ± 1.77 kPa). In vitro cytocompatibility, cell attachment and alkaline phosphatase (ALP) activity studies performed using rat bone marrow mesenchymal stem cells. Addition of b-TCP-Sr to collagen scaffolds increased ALP activity by 1.33–1.79 and 2.92–4.57 folds after 7 and 14 days of culture, respectively. CONCLUSION: In summary, it was found that the incorporation of Sr into the collagen-b-TCP scaffolds has a great potential for bone tissue engineering applications.

Modified DEBA for determining size dependent shear fracture energy of laminates

M. Saeed Goodarzi,Hossein Hosseini-Toudeshky 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.28 No.1

It has been argued that fracture energy of composite laminates depends on their thickness and number of layers. In this paper a modified direct energy balance approach (DEBA) has been developed to evaluate the mode-II shear fracture energy for E-glass/Epoxy laminates from finite element model at an arbitrary thickness. This approach considers friction and damage/plasticity deformations using cohesive zone modeling (CZM) and nonlinear finite element modeling. The presence of compressive stress and resulting friction was argued to be a possible cause for the thickness dependency of fracture energy. In the finite element modeling, CZM formulation has been developed with bilinear cohesive constitutive law combined with friction consideration. Also ply element have been developed with shear plastic damage model. Modified direct energy balance approach has been proposed for estimation of mode-II shear fracture energy. Experiments were performed on laminates of glass epoxy specimens for characterization of material parameters and determination of mode-II fracture energies for different thicknesses. Effect of laminate thickness on fracture energy of transverse crack tension (TCT) and end notched flexure (ENF) specimens has been numerically studied and comparison with experimental results has been made. It is shown that the developed numerical approach is capable of estimating increase in fracture energy due to size effect.

Geometric Control of a Quadrotor UAV Transporting a Payload Connected via Flexible Cable

Farhad A. Goodarzi,이대원,이태영 제어·로봇·시스템학회 2015 International Journal of Control, Automation, and Vol.13 No.6

We derived a coordinate-free form of equations of motion for a complete model of a quadrotor UAV with a payload which is connected via a flexible cable according to Lagrangian mechanics on a manifold. The flexible cable is modeled as a system of serially-connected links and has been considered in the full dynamic model. A geometric nonlinear control system is presented to asymptotically stabilize the position of the quadrotor while aligning the links to the vertical direction below the quadrotor. Numerical simulation and experimental results are presented and a rigorous stability analysis is provided to confirm the accuracy of our derivations. These results will be particularly useful for aggressive load transportation that involves large deformation of the cable.

Association between the incidence and mortality rates for corpus uteri cancer and human development index (HDI): a global ecological study

( Zaher Khazaei ),( Elham Goodarzi ),( Malihe Sohrabivafa ),( Hasan Naemi ),( Kamyar Mansori ) 대한산부인과학회 2020 Obstetrics & Gynecology Science Vol.63 No.2

Objective The aim of this study was to determine the association between the incidence of and mortality due to corpus uteri cancer (CUC) and the human development index (HDI) across the world. Methods This was an ecological study. The incidence and mortality rates of CUC along with HDI data were extracted from the Global Cancer Data in 2018. Subsequently, correlation coefficient and linear regression model were used to determine the association between the incidence and mortality rates of CUC and the HDI. STATA-14 was used for data analysis. Results There was a positive and significant correlation between the incidence (r=0.693; P<0.001) and mortality (r=0.284; P<0.001) rates of uterine cancer and the HDI. A positive and significant correlation was also observed between the incidence rate and the gross national income per 1,000 capita (r=0.440; P<0.001), mean years of schooling (MYS) (r=0.740; P<0.001), life expectancy at birth (LEB) (r=0.590; P<0.001), and expected years of schooling (r=0.650; P<0.001). The results of the linear regression model showed a significant statistical association between MYS and the incidence of CUC (β=1.10; 95% confidence interval [CI], 0.60-1.70) and LEB and mortality due to uteri cancer (β=0.40; 95% CI, 0.10-0.90). Conclusion The results of this study suggest a significant statistical association between the incidence and mortality rates of CUC and the HDI.