Fluid-structure coupling of concentric double FGM shells with different lengths

Ehsan Moshkelgosha,Ehsan Askari,정경훈,Ali Akbar Shafiee 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.61 No.2

The aim of this study is to develop a semi-analytical method to investigate fluid-structure coupling of concentric double shells with different lengths and elastic behaviours. Co-axial shells constitute a cylindrical circular container and a baffle submerged inside the stored fluid. The container shell is made of functionally graded materials with mechanical properties changing through its thickness continuously. The baffle made of steel is fixed along its top edge and submerged inside fluid such that its lower edge freely moves. The developed approach is verified using a commercial finite element computer code. Although the model is presented for a specific case in the present work, it can be generalized to investigate coupling of shellplate structures via fluid. It is shown that the coupling between concentric shells occurs only when they vibrate in a same circumferential mode number, n. It is also revealed that the normalized vibration amplitude of the inner shell is about the same as that of the outer shell, for narrower radial gaps. Moreover, the natural frequencies of the fluid-coupled system gradually decrease and converge to the certain values as the gradient index increases.

Bloom, Maturity, and Fruit Set of Pistachio in Response to Early Season Application of Ethephon

Ehsan Askari,Sayareh Irani,Khorshid Razmjoo 한국원예학회 2011 Horticulture, Environment, and Biotechnology Vol.52 No.1

Spring frost damage has been a problem in pistachio producing areas. This experiment was conducted to evaluate the effect of ethephon application rate and date on bloom and maturity delay, fruit set, and yield of ’Kalleh-guchi’ pistachio in Rafsanjan, Iran. Fourteen-year-old whole trees were sprayed with 0, 250, 500, and 750 mg・L-1 ethephon on February 10 or March 1 for single application and both dates for two applications. With increasing the application rate, timings of the initial and full bloom and the maturity were delayed by 11.2, 12.6, and 7.6 days in 2007 and 11.3, 10.7, and 5.4 days in 2008, respectively. The double spray was the most effective in delaying bloom and maturity, and in increasing yield. The double spray with 750 mg・L-1 ethephon delayed initial and full bloom, and maturity by 14, 15, and 10 days in 2007 and 15, 15, and 8 days in 2008, respectively. This treatment increased the yield by about 64% in both years. It was concluded that ethephon may be applied to pistachio in late winter to delay bloom in spring without any apparent side effects, and thus to prevent spring frost damage and increase the yield.

Effectiveness of Exogenous Salicylic Acid on Root and Shoot Growth Attributes, Productivity, and Water Use Efficiency of Water-deprived Fennel Genotypes

Ehsan Askari,Parviz Ehsanzadeh 한국원예학회 2015 Horticulture, Environment, and Biotechnology Vol.56 No.5

This study was carried out to investigate the response of fennel (Foeniculum vulgare Mill.) to water deficit and exogenous application of salicylic acid (SA). Six fennel genotypes, from Iran (namely ‘Urmia’, ‘Hamadan’, ‘Kerman’, ‘Shiraz’, ‘Birjand’ and ‘Yazd’) were subjected to two levels of irrigation consisting of either irrigation after 35% (control) or 75% depletion of available soil water (water deficit) and 3 levels of treatment with SA (0.0, 0.5 and 1.0 mM). Root growth attributes, yield and yield components as well as irrigation water use efficiencies for seed, oil and dry masses of the shoot and whole plant were studied. Shoot dry mass, grain yield and essential oil yield were decreased due to water deficit. Furthermore, root growth attributes were decreased under water deficit, except for root diameter and dry mass, and root/shoot ratio. With the exception of irrigation water use efficiency for seed yield, all irrigation water use efficiency aspects were increased when fennel was subjected to water deprivation. Fennel genotypes were grouped according to their stress susceptibility indices (SSI) into drought-tolerant, moderately drought-tolerant and drought-sensitive groups. The largest drought-induced decreases in root length, root dry mass, root length density, number of fruits per umbel, seed yield, 1000-seed weight, seed essential oil yield, and irrigation water use efficiency for seed and oil yield were observed in genotype ‘Hamadan’ from the drought-sensitive group. Salicylic acid led to increases in root growth and yield attributes, seed essential oil content and yield, and irrigation water use efficiency aspects under both moisture conditions. Overall, foliar application of SA appeared to attenuate the negative effects of drought stress on fennel through increases in most of the root growth and yield attributes and the attenuation was more substantial in the drought-tolerant set of fennel genotypes.

Memorial functional foods: a new concept from Bavi tribe

Ehsan Amiri Ardekani,Hossein Askari,Abdolali Mohagheghzadeh 한국식품연구원 2020 Journal of Ethnic Foods Vol.7 No.-

The use of functional foods (FFs) for maintaining health and preventing or treating illnesses—in recent years—has been dramatically increased in the literature. There are available valuable examples of FFs in ethno medicine from different tribes. Ethnic FFs can be valuable resources for developing FFs science, e.g., introducing memorial FFs as an interdisciplinary ethnopharmacological concept. In this paper, ethnic FFs from Bavi tribe (Kohgiluyeh va Boyerahmad province of Iran) have been studied, and their medical potentials are reported. Data gathering was done by interview with Bavi tribe local healers using a questionnaire. Plant materials were collected and identified, and Bavi FFs were prepared according to local procedures. Information of 21 Bavi tribe FFs was collected which are including 20 different plant species.The results showed that most FFs are used to treat chronic diseases including kidney problems like kidney stones, liver disease, neurological complaints, and GI ulcers and are used as lactogogue, while lesser FFs are used to treat acute diseases and symptoms (43%), including nausea and vomiting, common cold, diarrhea, sore throat, and allergy. Most FFs of Bavi tribe are prepared using aromatic plants (75%) responsible for aroma in the final FF. Probably, aromatic FFs increase patient acceptance, without mimicking unpleasant memory of drug recommendation. Plants that are used in FF are mostly perennial (80%) and wild growing (80%), indicating continuous contact of natives and so having memory with such habitant herbals. Treating diseases by homemade FFs which are prepared by well-known aromatic herbals is a routine procedure among natives like the Bavi tribe. Such easily made FFs with well-known taste and flavors which may change the patient’s mood should be studied in a new approach, “memorial FFs”, as a novel opportunity for healthcare and curing.

Novel combinatorial extensions to breakthrough curve modeling of an adsorption column — Depth filtration hybrid process

Ehsan Salehi,Mahdi Askari,Yaser Darvishi 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.86 No.-

This work introduces novel scenarios for the breakthrough curve modeling of an adsorption column/depthfiltration hybrid system. Four well-known theoretical breakthrough models including Thomas,Adams–Bohart, Yoon–Nelson, and BDST were employed to describe the normalized concentrationprofiles. In thefirst approach, the theoretical models were combined for better estimation of thebreakthrough curves and the Thomas/Yoon–Nelson and Thomas/BDST combinations were obtained asthe best extensions. In the second approach, an adsorption-transport model was developed for the depthfilter to obtain the transient concentration gradient across thefilter medium thickness. The model wasthen combined with the theoretical breakthrough models to predict the adsorption columnbreakthrough curves. Results revealed that a decrease in the feedflowrate andfilter pore size couldintensify the concentration polarization on thefilter surface. Both model extensions could successfullyapproximate the breakthrough curves of the hybrid system with more than 99% agreement withthe experimental data, while the prediction accuracy of the original breakthrough models seldomexceeds 93%.

Dynamic behavior of a functionally graded plate resting on Winkler elastic foundation and in contact with fluid

Ali A. Shafiee,Farhang Daneshmand,Ehsan Askari,Mojtaba Mahzoon 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.50 No.1

A semi-analytical method is developed to consider free vibrations of a functionally graded elastic plate resting on Winkler elastic foundation and in contact with a quiescent fluid. Material properties are assumed to be graded distribution along the thickness direction according to a power-law in terms of the volume fractions of the constituents. The fluid is considered to be incompressible and inviscid. In the analysis, the effect of an in-plane force in the plate due to the weight of the fluid is taken into account. By satisfying the compatibility conditions along the interface of fluid and plate, the fluid-structure interaction is taken into account and natural frequencies and mode shapes of the coupled system are acquired by employing energy methods. The results obtained from the present approach are verified by those from a finite element analysis. Besides, the effects of volume fractions of functionally graded materials, Winkler foundation stiffness and in-plane forces on the dynamic of plate are elucidated.

Dynamic behavior of a functionally graded plate resting on Winkler elastic foundation and in contact with fluid

Shafiee, Ali A.,Daneshmand, Farhang,Askari, Ehsan,Mahzoon, Mojtaba Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.50 No.1

A semi-analytical method is developed to consider free vibrations of a functionally graded elastic plate resting on Winkler elastic foundation and in contact with a quiescent fluid. Material properties are assumed to be graded distribution along the thickness direction according to a power-law in terms of the volume fractions of the constituents. The fluid is considered to be incompressible and inviscid. In the analysis, the effect of an in-plane force in the plate due to the weight of the fluid is taken into account. By satisfying the compatibility conditions along the interface of fluid and plate, the fluid-structure interaction is taken into account and natural frequencies and mode shapes of the coupled system are acquired by employing energy methods. The results obtained from the present approach are verified by those from a finite element analysis. Besides, the effects of volume fractions of functionally graded materials, Winkler foundation stiffness and in-plane forces on the dynamic of plate are elucidated.