Bridge-type structures analysis using RMP concept considering shear and bending flexibility

Mahmoud-Reza Hosseini-Tabatabaei,Mohmmad Rezaiee-Pajand,Mahmoud R. Mollaeinia 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.74 No.2

Researchers have elaborated several accurate methods to calculate member-end rotations or moments, directly, for bridge-type structures. Recently, the concept of rotation and moment propagation (RMP) has been presented considering bending flexibility, only. Through which, in spite of moment distribution method, all joints are free resulting in rotation and moment emit throughout the structure similar to wave motion. This paper proposes a new set of closed-form equations to calculate member-end rotation or moment, directly, comprising both shear and bending flexibility. Furthermore, the authors program the algorithm of Timoshenko beam theory cooperated with the finite element. Several numerical examples, conducted on the procedures, show that the method is superior in not only the dominant algorithm but also the preciseness of results.

Exact closed-form equations for internal forces functions of bridge-type structures

Mahmoud-Reza Hosseini-Tabatabaei,Mahmoud Reza Mollaeinia 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.80 No.2

Influence lines and internal forces functions are vital tools for designing and monitoring engineering structures. This research explored a static method to derive exact closed-form equations for internal forces functions of bridge-type structures, continuous beams, and bridge frames, considering the bending flexibility. For this aim, first, we achieved member-end moment functions by applying the moment-rotation relationships in conjunction with the rotation propagation method. Then, substituting these functions into the static equilibrium equations provided the desired functions in terms of both the unit load and intended cross-section positions all over the structure, subjected to concentrated loads. Finally, the authors solved three illustrative examples to clarify the dominance of their suggested method for constructing both influence line and internal forces diagrams of statically indeterminate structures.

Optimization of Direct Yellow 12 dye removal by nanoscale zero-valent iron using response surface methodology

Mahmoud Reza Sohrabi,Sama Amiri,Hamid Reza Fard Masoumi,Mina Moghri 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.4

Zero-valent iron nanoparticles were synthesized, for removal of Direct Yellow 12 dye. The experiments were designed by response surface methodology. Quadratic model was used to predict the variables. Analysis of variance was used for investigation of variables and interaction between them. High F-value (10.01), very low P-value (<0.0001), non-significant lack of fit, the determination coefficient (R2 = 0.903) and the adequate precision (10.82) demonstrate good correlation between experimental and predicted values of the response. The highest removal percent (90.02%) was attained, and the optimum parameters are achieved: catalyst amount (0.31 w/w%), initial concentration (40 mg/l), reaction time (105.35 s) and pH (5.23).

Can STOP Trial Velocity Criteria Be Applied to Iranian Children with Sickle Cell Disease?

Reza Bavarsad Shahripour,Martin M. Mortazavi,Kristian Barlinn,Bijan Keikhaei,Hadi Mousakhani,Mahmoud Reza Azarpazhooh,Morteza Oghbaee,Seyed Aidin Sajedi,Jessica Kepplinger,R. Shane Tubbs,Karen C. Albr 대한뇌졸중학회 2014 Journal of stroke Vol.16 No.2

Background and Purpose: Sickle cell disease (SCD) is strongly linked to stroke across all haplotypes in the pediatric population. Transcranial Doppler (TCD) ultrasound is known to identify the highest risk group in African-Americans who need to receive and stay on blood transfusions, but it is unclear if the same flow velocity cut-offs can be applied to the Iranian population. We aimed to evaluate baseline TCD findings in Iranian children with SCD and no prior strokes. Methods: Children with genetically confirmed SCD (Arabian haplotype, homozygote) and without SCD (controls) were prospectively recruited from pediatric outpatient clinic over a period of 9 months. We performed TCD in both groups to determine flow velocities in the middle cerebral (MCA) and terminal internal carotid arteries (TICA). Results: Of 74 screened children, 60 met the inclusion/exclusion criteria (62% female; mean age 10±4 years). Baseline characteristics did not differ between the cases and controls, except hemoglobin (Hb) which was significantly lower in the SCD group (P<0.001). The right MCA TAMM (Time Averaged Maximum Mean) was significantly higher than in controls (125+ 5.52 cm/s vs. 92.5+1.63 cm/s, P<0.001). Left MCA did not show differences. The TICA TAMM was also different between cases and controls (P<0.05). Conclusions: Among Iranian children with asymptomatic SCD and without receiving recent transfusion TCD velocities are higher as compared to healthy controls but appear much lower than those observed in STOP (Stroke Prevention Trial in Sickle Cell Anemia) studies. We hypothesize that some children at high risk may be present with velocities lower than 170-200 cm/s thresholds. A prospective validation of ethnicity-specific prognostic criteria is warranted.

Fuzzy Hype-Plane Variable Sliding Mode Control to Reduce Joint Vibrations

Mahmoud Reza Safaei Nasrabad,Ehsan Pouladi,Ghasem Sahamijoo,Alireza Salehi,Farzin Piltan,Nasri b. Sulaiman 보안공학연구지원센터 2014 International Journal of u- and e- Service, Scienc Vol.7 No.5

The sliding mode controller is used to speed up the error convergence when the error is greater than one. To reduce the error terminal sliding mode controller is recommended in this research. Fuzzy hype-plane variable sliding mode controller is adopted to guarantee the error convergence to zero in a finite time when the error is around the zero. The chattering in the conventional sliding model control systems is avoided with the employed continuous controller. To increase the system robustness in presence of uncertainty fuzzy logic controller is recommended. This technique is used to adjust the band of terminals. The simulation results show that the proposed scheme has strong robust against the uncertainties and disturbances, as well as leads to the convergence of the output to the desired value quickly and precisely than employing either sliding mode controller or terminal sliding mode controller alone.

RNAi and miRNA in Viral Infections and Cancers

Mollaie, Hamid Reza,Monavari, Seyed Hamid Reza,Arabzadeh, Seyed Ali Mohammad,Shamsi-Shahrabadi, Mahmoud,Fazlalipour, Mehdi,Afshar, Reza Malekpour Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12

Since the first report of RNA interference (RNAi) less than a decade ago, this type of molecular intervention has been introduced to repress gene expression in vitro and also for in vivo studies in mammals. Understanding the mechanisms of action of synthetic small interfering RNAs (siRNAs) underlies use as therapeutic agents in the areas of cancer and viral infection. Recent studies have also promoted different theories about cell-specific targeting of siRNAs. Design and delivery strategies for successful treatment of human diseases are becomingmore established and relationships between miRNA and RNAi pathways have been revealed as virus-host cell interactions. Although both are well conserved in plants, invertebrates and mammals, there is also variabilityand a more complete understanding of differences will be needed for optimal application. RNA interference (RNAi) is rapid, cheap and selective in complex biological systems and has created new insight sin fields of cancer research, genetic disorders, virology and drug design. Our knowledge about the role of miRNAs and siRNAs pathways in virus-host cell interactions in virus infected cells is incomplete. There are different viral diseases but few antiviral drugs are available. For example, acyclovir for herpes viruses, alpha-interferon for hepatitis C and B viruses and anti-retroviral for HIV are accessible. Also cancer is obviously an important target for siRNA-based therapies, but the main problem in cancer therapy is targeting metastatic cells which spread from the original tumor. There are also other possible reservations and problems that might delay or even hinder siRNA-based therapies for the treatment of certain conditions; however, this remains the most promising approach for a wide range of diseases. Clearly, more studies must be done to allow efficient delivery and better understanding of unwanted side effects of siRNA-based therapies. In this review miRNA and RNAi biology, experimental design, anti-viral and anti-cancer effects are discussed.

Platelet volume indices in patients with varicocele

Mahdavi-Zafarghandi, Reza,Shakiba, Behnam,Keramati, Mohammad Reza,Tavakkoli, Mahmoud The Korean Society for Reproductive Medicine 2014 Clinical and Experimental Reproductive Medicine Vol.41 No.2

Objective: This study sought to evaluate platelet volume indices (mean platelet volume [MPV], platelet distribution width [PDW], and platelet large cell ratio [P-LCR]) in varicocele patients, and compare it with platelet volume parameters in healthy controls. Methods: This cross-sectional study involved 2 groups: group 1 included 51 varicocele subjects and group 2 consisted of 50 healthy control subjects of similar ages. Peripheral venous blood samples were collected with ethylenediaminetetraacetic acid-K2 anticoagulant between 8:30 AM and 10 AM following an overnight fast. Platelet volume parameters (MPV, PDW, and P-LCR) were measured in both groups within 2 hours of sampling. Results: The mean PDW, MPV, and P-LCR were $13.9{\pm}2.5%$, $10.1{\pm}1.3fL$, and $27.3{\pm}7.8%$ in varicocele patients, respectively, and were $12.6{\pm}2.4%$, $9.3{\pm}1.1fL$, and $21.9{\pm}6.4%$ in the control group, respectively. The mean PDW, MPV, and P-LCR were significantly higher in the varicocele group than the control group. Conclusion: The results of the present study suggest that vascular components may play an important role in the pathophysiology of varicocele; therefore, there is a great need for prospective studies to confirm this relationship.

Optimum Dietary Protein Levels in Juvenile Beluga

Mahmoud Mohseni,Hamid reza Pourali,Young-Chul Kim,Sungchul C. Bai 한국수산과학회 양식분과 2009 한국수산과학회 양식분과 학술대회 Vol.2009 No.7

Application of power spectral density function for damage diagnosis of bridge piers

Mahmoud Bayat,Hamid Reza Ahmadi,Navideh Mahdavi 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.71 No.1

During the last two decades, much joint research regarding vibration based methods has been done, leading to developing various algorithms and techniques. These algorithms and techniques can be divided into modal methods and signal methods. Although modal methods have been widely used for health monitoring and damage detection, signal methods due to higher efficiency have received considerable attention in various fields, including aerospace, mechanical and civil engineering. Signal-based methods are derived directly from the recorded responses through signal processing algorithms to detect damage. According to different signal processing techniques, signal-based methods can be divided into three categories including time domain methods, frequency domain methods, and time-frequency domain methods. The frequency domain methods are well-known and interest in using them has increased in recent years. To determine dynamic behaviours, to identify systems and to detect damages of bridges, different methods and algorithms have been proposed by researchers. In this study, a new algorithm to detect seismic damage in the bridge’s piers is suggested. To evaluate the algorithm, an analytical model of a bridge with simple spans is used. Based on the algorithm, before and after damage, the bridge is excited by a sine force, and the piers’ responses are measured. The dynamic specifications of the bridge are extracted by Power Spectral Density function. In addition, the Least Square Method is used to detect damage in the bridge’s piers. The results indicate that the proposed algorithm can identify the seismic damage effectively. The algorithm is output-only method and measuring the excitation force is not needed. Moreover, the proposed approach does not need numerical models.

3D tomographic PIV, POD and vortex identification of turbulent slot jet flow impinging on a flat plate

Mahmoud Charmiyan,Ahmad Reza Azimian,Ebrahim Shirani,Fethi Aloui,Cedric Degouet,Dirk Michaelis 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.11

The impinging turbulent slot jet was investigated experimentally using tomographic particle image velocimetry technique. The jet Reynolds number was considered equal to 9000 and the nozzle to plate distance was 10 times the width of the nozzle. The mean flow and turbulent statistics were evaluated at different cross-sections. Then, the dominant three-dimensional structures of the turbulent flow were identified using the Proper orthogonal decomposition (POD) method, and the contribution of different energy modes to the total energy was determined. It is observed that the first 40 POD modes can be considered as the dominant flow modes which contain about 89 % of total kinetic energy of the flow. Also, horseshoe form structures were observed in some POD modes on both sides of the jet central plane. Finally, three-dimensional vortex structures were specified using vorticity, Q and λ 2 criteria, and compared with each other.