Magneto-electro-elastic vibration analysis of modified couple stress-based three-layered micro rectangular plates exposed to multi-physical fields considering the flexoelectricity effects

Mohammad Khorasani,Arameh Eyvazian,Mohammed Karbon,Abdelouahed Tounsi,Luca Lampani,Tamer A. Sebaey 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.26 No.3

In this paper, based on the CPT, motion equations for a sandwich plate containing a core and two integrated face-sheets have derived. The structure rests on the Visco-Pasternak foundation, which includes normal and shear modules. The piezo-magnetic core is made of CoFe₂O₄ and also is subjected to 3D magnetic potential. Two face sheets at top and bottom of the core are under electrical fields. Also, in order to obtain more accuracy, the effect of flexoelectricity has took into account at face sheets' relations in this work. Flexoelectricity is a property of all insulators whereby they polarize when subject to an inhomogeneous deformation. This property plays a crucial role in small-scale rather than macro scale. Employing CPT, Hamilton's principle, flexoelectricity considerations, the governing equations are derived and then solved analytically. By present work a detailed numerical study is obtained based on Piezoelectricity, Flexoelectricity and modified couple stress theories to indicate the significant effect of length scale parameter, shear correction factor, aspect and thickness ratios and boundary conditions on natural frequency of sandwich plates. Also, the figures show that there is an excellent agreement between present study and previous researches. These finding can be used for automotive industries, aircrafts, marine vessels and building industries.

A refined vibrational analysis of the FGM porous type beams resting on the silica aerogel substrate

Mohammad Khorasani,Luca Lampani,Abdelouahed Tounsi 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.47 No.5

Taking a look at the previously published papers, it is revealed that there is a porosity index limitation (around 0.35) for the mechanical behavior analysis of the functionally graded porous (FGP) structures. Over mentioned magnitude of the porosity index, the elastic modulus falls below zero for some parts of the structure thickness. Therefore, the current paper is presented to analyze the vibrational behavior of the FGP Timoshenko beams (FGPTBs) using a novel refined formulation regardless of the porosity index magnitude. The silica aerogel foundation and various hydrothermal loadings are assumed as the source of external forces. To obtain the FGPTB's properties, the power law is hired, and employing Hamilton's principle in conjunction with Navier's solution method, the governing equations are extracted and solved. In the end, the impact of the various variables as different beam materials, elastic foundation parameters, and porosity index is captured and displayed. It is revealed that changing hygrothermal loading from non-linear toward uniform configuration results in non-dimensional frequency and stiffness pushing up. Also, Al – Al2O3 as the material composition of the beam and the porosity presence with the O pattern, provide more rigidity in comparison with using other materials and other types of porosity dispersion. The presented computational model in this paper hopes to help add more accuracy to the structures’ analysis in high-tech industries.

Using artificial neural network for design and development of PVA/chitosan/starch/heparinized nZnO hydrogels for enhanced wound healing

Alireza Joorabloo,Mohammad Taghi Khorasani,Hassan Adeli,Peiman Brouki Milan,Moein Amoupour 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.108 No.-

A study of many individual parameters is required to provide a robust investigation of a system inbiomedical applications. A comprehensive understanding of these parameters is achievable by an appropriateexperimental model as a valid description to predict the outputs (responses). A combination ofresponse surface methodology and artificial neural network has been employed to design hydrogel dressingsincluding polyvinyl alcohol, chitosan, and starch. The optimal ratio of components of hydrogels asinput data based on the water vapor transmission rate, gel content, swelling ratio, and porosity propertiesas output parameters was determined using the quick propagation algorithm. Zinc-oxide nanoparticleswere coupled with heparin and applied in the optimal formulation to investigate its effect on physicaland mechanical properties, cytotoxicity, and antibacterial activities as well as in vivo wound healing. Mechanical strength improved in the presence of zinc-oxide nanoparticles. Heparin release reached withthe saturation state in a longer period after conjugation onto zinc-oxide nanoparticles. Minimum inhibitoryconcentration decreased significantly by conjugation of heparin to the nanoparticles and current systemscould protect wounds against infections. In vivo wound healing and immunohistochemistry assayindicated accelerated wound closure, re-epithelialization, and skin regeneration for hydrogel dressingscontaining heparin functionalized zinc-oxide nanoparticles.

Preparation and characterization of a thermal responsive of poly(N-isopropylacrylamide)/chitosan/gelatin hydrogels

Baghaei, Shaghayegh,Khorasani, Mohammad T. Techno-Press 2014 Biomaterials and Biomechanics in Bioengineering Vol.1 No.2

Synthesis of interpenetrating polymer network (IPN) of chitosan-gelatin (Cs-Ge) (as a primary network) and N-isopropylacrylamide (NIPAAm) monomer (as the secondary network) was carried out with different ratio. Its structure was characterized by FT-IR, which indicated that the IPN was formed. The memberanes were studied by swelling, weight loss with time. The interior morphology of the IPN hydrogels was revealed by scanning electron microscopy (SEM); the IPN hydrogels showed a interpenetrated network of NIPAAm/chitosan has layers with more minute stoma and canals compared to interpenetrated network of NIPAAm/gelatin. Lower critical solution temperature (LCST), equilibrium swelling ratio (ESR) and deswelling kinetics were measured. The DSC results noticed that LCST of IPN hydrogels with different ratio of Cs/Ge/PNIPAAm are around $33{\pm}2^{\circ}C$. The ESR obtained results showed that with a ratio of Cs/Ge/NIPAAm: 1/1/6, the swelling ratio increased drastically from room temperature to $36^{\circ}C$ but with a ratio of Cs/Ge/PNIPAAm: 1/3/6, decrease significantly at the same condition. Therefore the hydrogels have been changed from a hydrophilic structure to a hydrophobic structure. Furthermore with an increase in temperature from room to the LCST, the ESR of IPN with higher concentration of (PNIPAAm) and (Ge) decreases but de-swelling kinetics of them are faster. Due to the suitable and different kinetics of de-swelling and the equilibrium swelling ratio (ESR) in various proportions, and because of the morphology inside the mass which confirms other tests, these hydrogels are very appropriate as a smart thermosensitive hydrogels with rapid response.

Preparation and characterization of a thermal responsive of poly(N-isopropylacrylamide)/chitosan/gelatin hydrogels

Baghaei, Shaghayegh,Khorasani, Mohammad T. Techno-Press 2014 Biomaterials and biomedical engineering Vol.1 No.2

Synthesis of interpenetrating polymer network (IPN) of chitosan-gelatin (Cs-Ge) (as a primary network) and N-isopropylacrylamide (NIPAAm) monomer (as the secondary network) was carried out with different ratio. Its structure was characterized by FT-IR, which indicated that the IPN was formed. The memberanes were studied by swelling, weight loss with time. The interior morphology of the IPN hydrogels was revealed by scanning electron microscopy (SEM); the IPN hydrogels showed a interpenetrated network of NIPAAm/chitosan has layers with more minute stoma and canals compared to interpenetrated network of NIPAAm/gelatin. Lower critical solution temperature (LCST), equilibrium swelling ratio (ESR) and deswelling kinetics were measured. The DSC results noticed that LCST of IPN hydrogels with different ratio of Cs/Ge/PNIPAAm are around $33{\pm}2^{\circ}C$. The ESR obtained results showed that with a ratio of Cs/Ge/NIPAAm: 1/1/6, the swelling ratio increased drastically from room temperature to $36^{\circ}C$ but with a ratio of Cs/Ge/PNIPAAm: 1/3/6, decrease significantly at the same condition. Therefore the hydrogels have been changed from a hydrophilic structure to a hydrophobic structure. Furthermore with an increase in temperature from room to the LCST, the ESR of IPN with higher concentration of (PNIPAAm) and (Ge) decreases but de-swelling kinetics of them are faster. Due to the suitable and different kinetics of de-swelling and the equilibrium swelling ratio (ESR) in various proportions, and because of the morphology inside the mass which confirms other tests, these hydrogels are very appropriate as a smart thermosensitive hydrogels with rapid response.

Fabrication of heparinized nano ZnO/poly(vinylalcohol)/carboxymethyl cellulose bionanocomposite hydrogels using artificial neural network for wound dressing application

Alireza Joorabloo,Mohammad Taghi Khorasani,Hassan Adeli,Zohreh Mansoori-Moghadam,Armaghan Moghaddam 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.70 No.-

This study aimed to optimize hydrogel wound dressings to achieve favorable properties of the watervapor transmission rate (WVTR) and proper degree of swelling ratio (DSR) to overcome the issues oftenassociated with most commercial dressings including improper breathability and insufficient exudateabsorption. Artificial neural network and response surface methodologies were utilized to design andmodel bionanocomposites. Besides, the effect of the ratio of components as input data, and WVTR andDSR properties as output (response) data were investigated. Hydrogel systems were produced via thefreeze–thaw method and were identified using infrared spectroscopy, dynamic light scattering, andscanning electron microscopy. To increase the antibacterial property of manufactured specimens, zincoxide nanoparticles were functionalized with heparin, and, other properties including mechanicalproperties, in vitro wound healing as well as toxicity analysis were investigated on the optimumformulation. Results showed an improvement in mechanical properties in the presence of nanoparticlesand also enhanced antibacterial property after conjugating heparin on nanoparticles. In vitro healing andcell viability results approved the biocompatibility and non-toxicity of the samples. Therefore,manufactured dressings were considered to have good DSR and WVTR, mechanical and biocompatibilityproperties and they exhibited good ability to heal and protect wounds.

Assessing the Effects of Deforestation and Reforestation on Soil Carbon Dynamics and 14c Dating

Ebrahim Moghiseh,Ahmad Heidari,Mohammad Ghannadi,Hassan Tofighi,Fereydoon Sarmadian,Mostafa Karimian Eghbal,Nejat Pirvali,Sadollah Teimouri,Ali Khorasani 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Size-dependent flexoelectricity-based vibration characteristics of honeycomb sandwich plates with various boundary conditions

Soleimani-Javid, Zeinab,Arshid, Ehsan,Khorasani, Mohammad,Amir, Saeed,Tounsi, Abdelouahed Techno-Press 2021 Advances in nano research Vol.10 No.5

Flexoelectricity is an interesting materials' property that is more touchable in small scales. This property beside the sandwich structures placed in the center of scientists' attention due to their extraordinary effects on the mechanical properties. Furthermore, in the passage of decades, more elaborated sandwich structures took into consideration results from using honeycomb core. This kind of structure, inspiring from honeycomb core, provides more stiffness to weight ratio, which plays a crucial role in different industries. In this paper, based on the Love-Kirchhoff's hypothesis, Hamilton's principle, modified couple stress theory and Fourier series analytical method, equations of motion for a sandwich plate containing a honeycomb core integrated by two face-sheets have derived and solved analytically. The equations of both face sheets have derived by flexoelectricity consideration. Moreover, it should be noticed that the whole structure rests on the visco-Pasternak foundation. Conducting current research provided an acceptable and throughout study based on flexoelectricity to address the effect of materials' characteristics, length-scale parameter, aspect, and thickness ratios and boundary conditions on the natural frequency of honeycomb sandwich plates. Also, based on the presented figures and tables, there is a close agreement between previous studies and recent work. Due to the high ratio of strength to weight, current model analyzing is capable of taking into account for different vehicles' manufacturing in a high range of industries.