Optimization of Extended UNIQUAC Parameter for Activity Coefficients of Ions of an Electrolyte System using Genetic Algorithms

Hashemi, Seyed Hossein,Dehghani, Seyed Ali Mousavi,Khodadadi, Abdolhamid,Dinmohammad, Mahmood,Hosseini, Seyed Mohsen,Hashemi, Seyed Abdolrasoul The Korean Institute of Chemical Engineers 2017 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.55 No.5

In the present research, in order to predict activity coefficient of inorganic ions in electrolyte solution of a petroleum system, we studied 13 components in the electrolyte solution, including $H_2O$, $CO_2$ (aq), $H^+$, $Na^+$, $Ba^{2+}$, $Ca^{2+}$, $Sr^{2+}$, $Mg^{2+}$, $SO_4$, $CO_3$, $OH^-$, $Cl^-$, and $HCO_3$. To predict the activity coefficient of the components of the petroleum system (a solid/liquid equilibrium system), activity coefficient model of Extended UNIQUAC was studied, along with its adjustable parameters optimized based on a genetic algorithm. The total calculated error associated with optimizing the adjustable parameters of Extended UNIQUAC model considering the 13 components under study at three temperature levels (298.15, 323.15, and 373.15 K) using the genetic algorithm is found to be 0.07.

Relationship Between Dairy Intake and Hospitalization Risk and Disease Severity in Patients With COVID-19

Seyed Ali Abbas-Hashemi,Zahra Yari,Samira Soltanieh,Marieh Salavatizadeh,Sara Karimi,Sussan K. Ardestani,Mohammadreza Salehi,Soodeh Razeghi Jahromi,Tooba Ghazanfari,Azita Hekmatdoost 한국임상영양학회 2023 Clinical Nutrition Research Vol.12 No.4

The aim of this study was to investigate whether dairy intake was associated with the severity of coronavirus disease 2019 (COVID-19) disease and the probability of hospitalization of patients. This cross-sectional study was conducted on 141 patients with COVID-19 with an average age of 46.23 ± 15.88 years. The number of men (52.5%) participating in this study was higher than that of women. The association between dairy intake and COVID-19 was evaluated by multivariable logistic regression analysis. The risk of hospitalization in the highest tertile of dairy intake was 31% lower than in the lowest tertile (odds ratio [OR], 0.69; 95% confidence interval [CI], 0.37–1.25, p trend = 0.023). Higher milk and yogurt intake was associated with a reduced risk of hospitalization due to COVID-19. Patients in the third tertiles were about 65% (p for trend = 0.014) and 12% (p for trend = 0.050) less likely to be hospitalized than those in the first tertile, respectively. Dairy consumption, especially low-fat ones, was associated with a lower risk of hospitalization due to COVID-19 and lower severity of COVID-19.

Evaluation of unanchorage blast-resistant modular structures subjected to blast loads and human injury response

Ali Sari,Omer Faruk Nemutlu,Kadir Guler,Sayed Mahdi Hashemi 국제구조공학회 2024 Structural Engineering and Mechanics, An Int'l Jou Vol.89 No.5

An explosion from a specific source can generate high pressure, causing damage to structures and people in and around them. For the design of protective structures, although explosion overpressure is considered the main loading parameter, parts are only considered using standard design procedures, excluding special installations. Properties of the explosive, such as molecular structure, shape, dimensional properties, and the physical state of the charge, determine the results in a high-grade or low-grade explosion. In this context, it is very important to determine the explosion behaviors of the structures and to take precautions against these behaviors. Especially structures in areas with high explosion risk should be prepared for blast loads. In this study, the behavior of non-anchored blast resistant modular buildings was investigated. In the study, analyzes were carried out for cases where modular buildings were first positioned on a reinforced concrete surface and then directly on the ground. For these two cases, the behavior of the modular structure placed on the reinforced concrete floor against burst loads was evaluated with Stribeck curves. The behavior of the modular building placed directly on the ground is examined with the Pais and Kausel equations, which consider the structure-ground interaction. In the study, head and neck injuries were examined by placing test dummies to examine human injury behavior in modular buildings exposed to blast loads. Obtained results were compared with field tests. In both cases, results close to field tests were obtained. Thus, it was concluded that Stribeck curves and Pais Kausel equations can reflect the behavior of modular buildings subjected to blast loads. It was also seen at the end of the study that the human injury criteria were met. The results of the study are explained with their justifications.

Flexural ductility of reinforced HSC beams strengthened with CFRP sheets

Hashemi, Seyed Hamid,Maghsoudi, Ali Akbar,Rahgozar, Reza Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.30 No.4

Externally bonding fiber reinforced polymer (FRP) sheets with an epoxy resin is an effective technique for strengthening and repairing reinforced concrete (RC) beams under flexural loads. Their resistance to electro-chemical corrosion, high strength-to-weight ratio, larger creep strain, fatigue resistance, and nonmagnetic and nonmetallic properties make carbon fiber reinforced polymer (CFRP) composites a viable alternative to bonding of steel plates in repair and rehabilitation of RC structures. The objective of this investigation is to study the effectiveness of CFRP sheets on ductility and flexural strength of reinforced high strength concrete (HSC) beams. This objective is achieved by conducting the following tasks: (1) flexural four-point testing of reinforced HSC beams strengthened with different amounts of cross-ply of CFRP sheets with different amount of tensile reinforcement up to failure; (2) calculating the effect of different layouts of CFRP sheets on the flexural strength; (3) Evaluating the failure modes; (4) developing an analytical procedure based on compatibility of deformations and equilibrium of forces to calculate the flexural strength of reinforced HSC beams strengthened with CFRP composites; and (5) comparing the analytical calculations with experimental results.

Effect of Stress Conditions on Collapse Deformation Behavior of a Rockfill Material

Ali Akbar Heshmati,Ahmadreza Tabibnejad,Hossein Salehzadeh,Saeed Hashemi Tabatabaei 대한토목학회 2015 KSCE JOURNAL OF CIVIL ENGINEERING Vol.19 No.6

A set of saturated and dry-saturated large-scale triaxial tests were conducted in order to explore the effects of stress conditions on the saturation-induced collapse deformation behavior of a rockfill material. Specimens were tested in different confining pressures and for dry-saturated tests the specimens were submerged in various shear stress levels. The results indicate that in all of the drysaturated tests a sudden reduction in the volume of the specimens was observed during the submerging process. The ratio of the minimum axial strength of a submerged specimen (at the end of the saturation process) to the shear strength of the specimen before saturation is defined as the coefficient of stress recovery, Csr. Results of the dry-saturated tests showed that this ratio increases as the confining pressure increases and decreases by increasing the shear stress level. According to the results of dry-saturated tests the values of internal friction angle reduction caused by saturation (Δφc), the ratio of the elasticity modulus of the material after saturation to its elasticity modulus in dry condition, i.e., Ewet/Edry, and also the saturation induced sudden volumetric strain (εvc) decrease as the confining pressure increases. However the shear stress level does not have any meaningful effect on the variation of Dfc, Ewet/Edry and (εvc).

Fuzzy Linear Parameter Varying Modeling and Control of an Anti-Air Missile

Ali Reza Mehrabian,Seyed Vahid Hashemi 대한전기학회 2007 International Journal of Control, Automation, and Vol.5 No.3

An analytical framework for fuzzy modeling and control of nonlinear systems using a set of linear models is presented. Fuzzy clustering is applied on the aerodynamic coefficients of a missile to obtain an optimal number of rules in a Tagaki-Sugeno fuzzy rule-set. Next, the obtained membership functions and rule-sets are applied to a set of linear optimal controllers towards extraction of a global controller. Reported simulations demonstrate the performance, stability, and robustness of the controller.

Comparison of Conventional and Hypofractionated Radiotherapy in Breast Cancer Patients in Terms of 5-Year Survival, Locoregional Recurrence, Late Skin Complications and Cosmetic Results

Hashemi, Farnaz Amouzegar,Barzegartahamtan, Mohammadreza,Mohammadpour, Reza Ali,Sebzari, Ahmadreza,Kalaghchi, Bita,Haddad, Peiman Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.11

Bckground: Adjuvant radiation therapy is commonly administered following breast-conserving surgery for breast cancer patients. Hypofractionated radiotherapy can significantly reduce the waiting time for radiotherapy, working load on machines, patient visits to radiotherapy departments and medical costs. Material/Methods: Fifty-two patients with operable breast cancer (pT1-3pN0M0) who underwent breast conservation surgery in Tehran Cancer Institute during January 2011 to January 2012, were randomly assigned to undergo radiotherapy in two arms (hypofractionated radiotherapy arm with 30 patients, dose 42.5 Gy in 16 fractions; and conventional radiotherapy arm with 22 patients, dose 50 Gy in 25 fractions). W compared these two groups in terms of overall survival, locoregional control, late skin complications and cosmetic results. Results: At a median follow-up of 52.4 months (range: 0-64 months), the follow-up rate was 82.6%. Overall, after 60 months, there was no detectable significant differences between groups regarding cosmetic results (p = 0.857), locoregional control or survival. Conclusions: The results confirm that hypofractionated radiotherapy with a subsequent boost is as effective as conventional radiotherapy, is well-tolerated and can be used as an alternative treatment method following breast conservation surgery.

Effective number of mega-bracing, in order to minimize shear lag

Zahiri-Hashemi, Rouzbeh,Kheyroddin, Ali,Farhadi, Basir Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.48 No.2

In this paper, influence of geometric configurations of multi-story bracing on shear lag behaviour of braced tube structures is investigated. The shear lag of 24-, 36- and 72-story braced tube structures are assessed considering all possible configurations of overall X and Chevron bracing types. Based on the analytical results, empirical equations, useful for the preliminary design phase, are proposed to provide the optimum number of stories that braced, in order to exert minimum shear lag on structures. Studying the interaction behaviour of a tube and different bracing types along with paying attention to the shear lag behaviour, a better explanation about the reasons behind the efficiency of a specific bracing module in decreasing the shear lag is developed. The analytical results show that there are distinct differences between the anatomy of braced tube structures with X and Chevron bracing regarding the shear lag behaviour.

Synthesis and characterization of silanized-SiO2/povidone nanocomposite as a gate insulator: The influence of Si semiconductor film type on the interface traps by deconvolution of Si2s

Adeleh Hashemi,Ali Bahari 한국물리학회 2018 Current Applied Physics Vol.18 No.12

The polymer nanocomposite as a gate dielectric film was prepared via sol-gel method. The formation of crosslinked structure among nanofillers and polymer matrix was proved by Fourier transform infrared spectroscopy (FT-IR). Differential thermal analysis (DTA) results showed significant increase in the thermal stability of the nanocomposite with respect to that of pure polymer. The nanocomposite films deposited on the p- and n-type Si substrates formed very smooth surface with rms roughness of 0.045 and 0.058 nm respectively. Deconvoluted Si2s spectra revealed the domination of the SieOH hydrogen bonds and SieOeSi covalence bonds in the structure of the nanocomposite film deposited on the p- and n-type Si semiconductor layers respectively. The fabricated n-channel field-effect-transistor (FET) showed the low threshold voltage and leakage currents because of the stronger connection between the nanocomposite and n-type Si substrate. Whereas, dominated hydroxyl groups in the nanocomposite dielectric film deposited on the p-type Si substrate increased trap states in the interface, led to the drop of FET operation.

Integrated Fault Tolerant Control for Saturated Systems with Additive Faults: A Comparative Study of Saturation Models

Mojtaba Hashemi,Ali Kamali Egoli,Mahyar Naraghi 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.4

In this paper, the integrated design problem of Fault Estimation (FE) and Fault Tolerant Control (FTC)for saturated systems is considered. The system suffers from input saturation and L2-bounded disturbances. To designan adaptive observer-based FE, the actuator output measurements are not used, when the actuator is saturated,there exist new interactions between FE and FTC. In such a case the separation principle for FE and FTC designdoes not hold anymore. In this paper, a method is introduced for integrated design of FE and FTC, which guaranteesboundedness stability of such a system. To extract sufficient conditions for stability and minimum L2-gainperformance for disturbance rejection, the Modified Sector Condition (MSC) is employed for saturation modeling. Also, Quadratic Polytopic Differential Inclusion (QPDI) approach is developed for the comparative study. All conditionsare cast as Linear Matrix Inequality(LMIs) that can be evaluated in a single step. In a numerical example,the feasibility of the introduced method for stability guarantee is demonstrated and performance characteristics ofFE and FTC in disturbance rejection are compared for both modeling approaches.