Exact solution for transverse bending analysis of embedded laminated Mindlin plate

Heydari, Mohammad Mehdi,Kolahchi, Reza,Heydari, Morteza,Abbasi, Ali Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.5

Laminated Rectangular plates embedded in elastic foundations are used in many mechanical structures. This study presents an analytical approach for transverse bending analysis of an embedded symmetric laminated rectangular plate using Mindlin plate theory. The surrounding elastic medium is simulated using Pasternak foundation. Adopting the Mindlin plate theory, the governing equations are derived based on strain-displacement relation, energy method and Hamilton's principle. The exact analysis is performed for this case when all four ends are simply supported. The effects of the plate length, elastic medium and applied force on the plate transverse bending are shown. Results indicate that the maximum deflection of the laminated plate decreases when considering an elastic medium. In addition, the deflection of the laminated plate increases with increasing the plate width and length.

Exact solution for transverse bending analysis of embedded laminated Mindlin plate

Mohammad Mehdi Heydari,Reza Kolahchi,Morteza Heydari,Ali Abbasi 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.5

Laminated Rectangular plates embedded in elastic foundations are used in many mechanical structures. This study presents an analytical approach for transverse bending analysis of an embedded symmetric laminated rectangular plate using Mindlin plate theory. The surrounding elastic medium is simulated using Pasternak foundation. Adopting the Mindlin plate theory, the governing equations are derived based on strain-displacement relation, energy method and Hamilton’s principle. The exact analysis is performed for this case when all four ends are simply supported. The effects of the plate length, elastic medium and applied force on the plate transverse bending are shown. Results indicate that the maximum deflection of the laminated plate decreases when considering an elastic medium. In addition, the deflectionof the laminated plate increases with increasing the plate width and length.

Esophageal, Gastric and Duodenal Disorders : The Associated Factors of Gastro-Esophageal Reflux Disease (GERD) in Shiraz, Southern Iran

( Mehdi Saberi Firouzi ),( Famaz Khademolhosseini ),( Maryam Yousefi ),( Davood Mehrabani ),( Najaf Zare ),( Seyed Taghi Heydari ) 대한소화기학회 2007 SIDDS Vol.9 No.-

Aim: Symptoms of gastroesophageal reflux disease (GERD) represent one of the most common problems in the western world. The aim of this study was to determine the prevalence and symptoms of GEFD in a healthy general population in relation to demographic, lifestyle and health-seeking behaviors in Shiraz, southern Iran. Methods: 1978 subjects of >35 years old who referred to Gastroenterohepatology Research Center and completed a questionnaire consisting of 53 questions for GERD in relation to demographic, lifestyle and health-seeking behavior were enrolled in our study during a period of five months. The validity and reliability of the questionnaire were determined. Results: The prevalence of GERD was 15.4%, which was more in females (17.3%), in rural areas (19.8%), in illiterate subjects (21.5%) and in the mean age of 50.25 years. There was significantly a lower prevalence in subjects having fried foods (14.8%), and fruit and vegetables (14.6%). We noticed more symptoms in subject consuming pickles (22.1%), taking Aspirin (21%) and in subjects with psychological distresses. (27.2%) and headaches (22%). The correlation between GERD and halitosis (18.3%), dyspepsia (30.6%), anxiety (19.5%), nightmares (23.9%) and restlessness (18.5%) was statistically significant. Their health seeking behavior showed that there was a significant restriction of diet (20%), consumption of herbal medicine (19%), using over-the-counter drugs (29.9%), and visiting a physician (24.8%). Presence of GERD symptoms was also significantly related to previous family history of the disease (22.3%). Conclusion: GERD was significantly more in females, rural and illiterate subjects and had a correlation with consumption of pickles, headache, psychological distress, dyspepsia, halitosis, anxiety, nightmare, restlessness and pervious history of GERD in the family and aspirin intake but the correlation was inverse with consumption of fat and fiber intake.

Feasibility of pilot-scale disc-donut column for continuous cadmium extraction with the perspective of droplet size distribution

Asadollahzadeh Mehdi,Torkaman Rezvan,Torab-Mostaedi Meisam,Heydari Ali 한국자원공학회 2021 Geosystem engineering Vol.24 No.6

Heavy metal removal is a significant problem in various industries. Liquid-liquid extraction is a practical process in recovering these elements. In this study, the behavior of pilot-scale disc-donut column in the extraction of cadmium ions was evaluated. The effects of droplets with the variation size distributions are significant in describing performance and characteristics of an extractor for removing the substrate from aqueous or organic phases. The size distribution of droplets is relative to the interfacial area under steady conditions. To match the size distribution of droplets, the experiments are carried out in reaction and non-reaction conditions. In emulsion regime (pulsing intensity (Af), inlet organic and aqueous phase flow rate (Vc, Vd) equal to 3.3 cm/s, 2.22 mm/s, and 2.22 mm/s, respectively) and under the optimized conditions, 99.7% of the cadmium can be recovered from the aqueous solution. It was found that Weibull distribution gives the best fit at each operation mode while inverse Gaussian distribution gives the most inferior fit. According to a series of statistical analyses, it is shown that the pulsation intensity imposed more influence on drop sizes, and superficial flow rates of both phases are less able to the successful prediction of size distribution of droplets.

Two new relationships for slip velocity and characteristic velocity in a non-center rotating column

Torkaman Rezvan,Heydari Mehran,Cheshmeh Javad Najafi,Heydari Ali,Asadollahzadeh Mehdi 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.8

In this investigation work, liquid-liquid extraction (L.L.E) through three distinctive frameworks have been examined for assurance of slip velocity (S.V), and characteristic velocity (C.V) in a non-center rotating column (N.C.R.C) with a wide extend of factors. Three double frameworks with distinctive interfacial tension comprising of toluene-water (high interfacial tension), n-butyl acetateewater (medium interfacial tension), and n-butanolewater (low interfacial tension) were investigated for tests. Two common relationships for the expectation of S.V and C.V, including phase stream rates, rotor speed, column geometry additionally physical properties, are displayed. The recommended relationships were compared with test information gotten from the writing and the display examination. Findings of this study, the present proposed correlations are more accurate than those previously reported.

Adaptive plasticity of morphological and anatomical traits of Brant’s oak (Quercus brantii Lindl.) leaves under different climates and elevation gradients

Soheili Forough,Heydari Mehdi,Woodward Stephen,Abdul-Hamid Hazandy,Naji Hamid Reza 한국산림과학회 2023 Forest Science And Technology Vol.19 No.2

The morphological and anatomical characteristics of leaves are sensitive and adaptable to environmental changes. Determining eco-physiological patterns of leaf characteristics along elevational gradients allows for a better understanding and prediction of how plants might respond to climate change. In this work, the ecological adaptation mechanisms related to morphological and anatomical characteristics of Brant’s oak (Quercus brantii Lindl.) leaves were studied at three elevation classes (low, middle, and high) in two different Mediterranean and subhumid climates in Zagros forests in western Iran. There were no sig- nificant changes in leaf length, although the leaf-specific area was higher at low and middle elevations in subhumid climates. In addition, stomata length, width, density, and stomatal pore index were higher in the upper elevations of subhumid climate than in the Mediterranean climate. At low and middle elevations, dry matter content was higher at sites from the Mediterranean climate. The results of plasticity indices showed that individuals of Q. brantii from middle-elevation sites exhibited greater plasticity than those from low and high-elevation sites. Overall, Q. brantii, the dominant oak species in Zagros forests, appears to respond to elevational and environmental changes, suggesting that leaves can adapt to these changes through morphological and anatomical traits. These results provide new insights into the environmental adaptation strategies of plants at the morphological and anatomical levels against climate change.

Experimental investigation of the effect of baffles on the efficiency improvement of irrigation sedimentation tank structures

Alireza Zamani Nouri,Mohammad Mehdi Heydari 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.4

Sedimentation tanks are essential structures to filter the suspended sediments in the inlet flow which are constructed at the inlet of the basins forked from rivers and irrigation canals. The larger the constructed tank, the better the sedimentation process is conducted. However, the construction and dredging costs increase. In this regard, improving the performance and sedimentation efficiency seem necessary by alternative methods. One of these effective methods is using baffle plates. Most of the studies carried out in this field are on the use of these baffles in the primary and secondary sedimentation tanks. Hence, this study is carrier out with the objective of increasing the retention efficiency in the irrigation sedimentation tanks using baffles. To reach this goal, the experiments were carried out in a flume with length 8 meters, width 0.3 meters, and height 0.5 meters, considering a sedimentation tanks with a length of 3 meters, in three different inlet concentration, three flow rates and three Froude numbers. The baffles were mounted at the bottom of the tank and the effects of the angle, height and position in the tanks were investigated. The results showed that on average, employing the baffles increased the sedimentation efficiency 5 to 6% and the highest value was obtained for angle 60 with respect to the flow direction. According to the results of this study, the most favorable height and position of these baffles were obtained to be in 40% of the depth of the flow and 50% of the length of the sedimentation tank, respectively. Also, by increasing the number of baffles, the sedimentation efficiency decreased. Regarding the sedimentation regions in this case, more than 80% of the settled sediments were observed in the middle of the tank measured from the inlet.

Experimental investigation of the effect of baffles on the efficiency improvement of irrigation sedimentation tank structures

Nouri, Alireza Zamani,Heydari, Mohammad Mehdi Techno-Press 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.4

Sedimentation tanks are essential structures to filter the suspended sediments in the inlet flow which are constructed at the inlet of the basins forked from rivers and irrigation canals. The larger the constructed tank, the better the sedimentation process is conducted. However, the construction and dredging costs increase. In this regard, improving the performance and sedimentation efficiency seem necessary by alternative methods. One of these effective methods is using baffle plates. Most of the studies carried out in this field are on the use of these baffles in the primary and secondary sedimentation tanks. Hence, this study is carrier out with the objective of increasing the retention efficiency in the irrigation sedimentation tanks using baffles. To reach this goal, the experiments were carried out in a flume with length 8 meters, width 0.3 meters, and height 0.5 meters, considering a sedimentation tanks with a length of 3 meters, in three different inlet concentration, three flow rates and three Froude numbers. The baffles were mounted at the bottom of the tank and the effects of the angle, height and position in the tanks were investigated. The results showed that on average, employing the baffles increased the sedimentation efficiency 5 to 6% and the highest value was obtained for angle 60 with respect to the flow direction. According to the results of this study, the most favorable height and position of these baffles were obtained to be in 40% of the depth of the flow and 50% of the length of the sedimentation tank, respectively. Also, by increasing the number of baffles, the sedimentation efficiency decreased. Regarding the sedimentation regions in this case, more than 80% of the settled sediments were observed in the middle of the tank measured from the inlet.

The Predictive Value of Point-of-care Ultrasonography versus MRI in Assessing Medial Meniscal Tears in Patients with Acute Knee Injury

Ahmadi Omid,Motififard Mehdi,Heydari Farhad,Hatami Saeed,Meibody Azita Azimi 대한응급의학회 2024 Clinical and Experimental Emergency Medicine Vol.11 No.2

Objective Musculoskeletal ultrasound is increasingly used as the modality of choice in diagnosing many medical situations. The present study aimed to compare the accuracy of point-of-care ultrasonography (POCUS) and magnetic resonance imaging (MRI) to detect acute medial meniscus tears in knee. Methods The prospective study was conducted on patients with suspected medial meniscus tears in knee. in the emergency department. In the absence of a knee fracture on x-ray, POCUS on the knee was performed. All patients underwent POCUS and MRI of the knee followed by arthroscopy. POCUS findings were then compared to MRI findings to diagnose medial meniscus tears. Results A final total of 157 patients with a mean age of 25.04±7.41 years was included. Out of 157 patients, 94 (59.9%) were male. Medial meniscus tears were detected in 89 patients (56.7%) using arthroscopy as the gold standard. The sensitivity, specificity, positive and negative predictive values, and accuracy of POCUS to detect medial meniscus tears were 88.8% (95% confidence interval [CI], 80.3%–94.5%), 89.7% (95% CI, 79.9%–95.8%), 91.9% (95% CI, 84.8%–95.8%), 85.9% (95% CI, 77.2%–91.7%), and 89.2% (95% CI, 83.3%–93.6%), respectively. The diagnostic accuracy of MRI to detect medial meniscus injury was 93.0% (95% CI, 87.8%– 96.4%). Conclusion The present study demonstrated that POCUS is an accurate and reliable diagnostic tool alternative to MRI in detecting medial meniscal tears. POCUS had acceptable sensitivity, specificity, and accuracy in detecting meniscal injuries and could be performed as an effective immediate investigation to guide further modalities in patients with acute knee trauma.

Size-dependent bending analysis of FGM nano-sinusoidal plates resting on orthotropic elastic medium

Reza Kolahchi,Ali Mohammad Moniri Bidgoli,Mohammad Mehdi Heydari 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.55 No.5

Bending analysis of functionally graded (FG) nano-plates is investigated in the present work based on a new sinusoidal shear deformation theory. The theory accounts for sinusoidal distribution of transverse shear stress, and satisfies the free transverse shear stress conditions on the top and bottom surfaces of the plate without using shear correction factor. The material properties of nano-plate are assumed to vary according to power law distribution of the volume fraction of the constituents. The size effects are considered based on Eringen's nonlocal theory. Governing equations are derived using energy method and Hamilton’s principle. The closed-form solutions of simply supported nano-plates are obtained and the results are compared with those of first-order shear deformation theory and higher-order shear deformation theory. The effects of different parameters such as nano-plate length and thickness, elastic foundation, orientation of foundation orthtotropy direction and nonlocal parameters are shown in dimensionless displacement of system. It can be found that with increasing nonlocal parameter, the dimensionless displacement of nanoplate increases.