DSpace :: Browsing by Author "Koloor, Seyed Saeid Rahimian"

Browsing by Author "Koloor, Seyed Saeid Rahimian"

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A Review on Vehicle Classification and Potential Use of Smart Vehicle-Assisted Techniques
(MDPI, 2020-06-08) Shokravi, Hoofar; Shokravi, Hooman; Bakhary, Norhisham; Heidarrezaei, Mahshid; Koloor, Seyed Saeid Rahimian; Petrů, Michal
Vehicle classification (VC) is an underlying approach in an intelligent transportation system and is widely used in various applications like the monitoring of traffic flow, automated parking systems, and security enforcement. The existing VC methods generally have a local nature and can classify the vehicles if the target vehicle passes through fixed sensors, passes through the short-range coverage monitoring area, or a hybrid of these methods. Using global positioning system (GPS) can provide reliable global information regarding kinematic characteristics; however, the methods lack information about the physical parameter of vehicles. Furthermore, in the available studies, smartphone or portable GPS apparatuses are used as the source of the extraction vehicle’s kinematic characteristics, which are not dependable for the tracking and classification of vehicles in real time. To deal with the limitation of the available VC methods, potential global methods to identify physical and kinematic characteristics in real time states are investigated. Vehicular Ad Hoc Networks (VANETs) are networks of intelligent interconnected vehicles that can provide traffic parameters such as type, velocity, direction, and position of each vehicle in a real time manner. In this study, VANETs are introduced for VC and their capabilities, which can be used for the above purpose, are presented from the available literature. To the best of the authors’ knowledge, this is the first study that introduces VANETs for VC purposes. Finally, a comparison is conducted that shows that VANETs outperform the conventional techniques.
An analytical conductance model for gas detection based on a zigzag carbon nanotube sensor
(MDPI, 2020-01-01) Hosseingholipourasl, Ali; Ariffin, Sharifah Hafizah Syed; Ahmadi, Mohammad Taghi; Koloor, Seyed Saeid Rahimian; Petrů, Michal; Hamzah, Afiq
Recent advances in nanotechnology have revealed the superiority of nanocarbon species such as carbon nanotubes over other conventional materials for gas sensing applications. In this work, analytical modeling of the semiconducting zigzag carbon nanotube field-effect transistor (ZCNT-FET) based sensor for the detection of gas molecules is demonstrated. We propose new analytical models to strongly simulate and investigate the physical and electrical behavior of the ZCNT sensor in the presence of various gas molecules (CO2, H2O, and CH4). Therefore, we start with the modeling of the energy band structure by acquiring the new energy dispersion relation for the ZCNT and introducing the gas adsorption effects to the band structure model. Then, the electrical conductance of the ZCNT is modeled and formulated while the gas adsorption effect is considered in the conductance model. The band structure analysis indicates that, the semiconducting ZCNT experiences band gap variation after the adsorption of the gases. Furthermore, the bandgap variation influences the conductance of the ZCNT and the results exhibit increments of the ZCNT conductance in the presence of target gases while the minimum conductance shifted upward around the neutrality point. Besides, the I-V characteristics of the sensor are extracted from the conductance model and its variations after adsorption of different gas molecules are monitored and investigated. To verify the accuracy of the proposed models, the conductance model is compared with previous experimental and modeling data and a good consensus is observed. It can be concluded that the proposed analytical models can successfully be applied to predict sensor behavior against different gas molecules.
Application of the Subspace-Based Methods in Health Monitoring of Civil Structures: A Systematic Review and Meta-Analysis
(MDPI, 2020-05-01) Shokravi, Hoofar; Shokravi, , Hooman; Bakhary, Norhisham; Heidarrezaei, Mahshid; Koloor, Seyed Saeid Rahimian; Petrů, Michal
A large number of research studies in structural health monitoring (SHM) have presented, extended, and used subspace system identification. However, there is a lack of research on systematic literature reviews and surveys of studies in this field. Therefore, the current study is undertaken to systematically review the literature published on the development and application of subspace system identification methods. In this regard, major databases in SHM, including Scopus, Google Scholar, and Web of Science, have been selected and preferred reporting items for systematic reviews and meta-analyses (PRISMA) has been applied to ensure complete and transparent reporting of systematic reviews. Along this line, the presented review addresses the available studies that employed subspace-based techniques in the vibration-based damage detection (VDD) of civil structures. The selected papers in this review were categorized into authors, publication year, name of journal, applied techniques, research objectives, research gap, proposed solutions and models, and findings. This study can assist practitioners and academicians for better condition assessment of structures and to gain insight into the literature.
Assessment of Compressive Mechanical Behavior of Bis-GMA Polymer Using Hyperelastic Models
(MDPI, 2019-10-01) Karimzadeh, Atefeh; Ayatollahi, Majid Reza; Koloor, Seyed Saeid Rahimian
Despite wide industrial applications of Bis-GMA polymer, very few studies are available about the material classification, mechanical properties, and behavior of this material. In this study, the compressive behavior of Bis-GMA polymer was studied using different hyperelastic constitutive models through a hybrid experimental-computational process. Standard uniaxial compression tests were conducted to extract the mechanical behavior and structural response of the Bis-GMA polymer. A nano-indentation experiment was used to verify the compressive behavior of Bis-GMA polymer in the form of hyperelastic behavior. The finite element model and real-time simulation of the test incorporating different hyperelastic models were developed in comparison with the experimental finding to obtain the proper type of hyperelastic behavior of Bis-GMA polymer. The results indicate that a second-order polynomial hyperelastic model is the best fit to predict the behavior of Bis-GMA polymer. Next, the validated model was used to determine the true stress-strain curve of the Bis-GMA polymer.
Carbon Nanoparticle-Based Electro-Thermal Building Block
(MDPI, 2020-01-01) Taghi Ahmadi, Mohammad; Mousavi, Neda; Khang Nguyen, Truong; Koloor, Seyed Saeid Rahimian; Petrů, Michal
All around the world, researchers have raised concerns about the superlative geometrical, electronic, thermal, chemical and mechanical properties of carbon nanoparticles (CNPs). CNPs with low cost, high performance and prominent intrinsic properties have attracted extensive interest for numerous applications in various fields. Although CNPs have been studied mainly as transistors and sensors, they could also be considered as heat producers. However, this option has scarcely been studied. In this research, a CNP-based electro-thermal building block is synthesized by the arc discharge method in a carbonic medium (high-density polyethylene), and its behavior is investigated. It is shaped in the form of a metal–semiconductor–metal structure (MSM) between metallic electrodes, and in addition, the formation of two back-to-back Schottky diodes is analyzed and their use as CNP-based electro-thermal building blocks are reported.
Carbon-Based Band Gap Engineering in the h-BN Analytical Modeling
(MDPI, 2020-04-27) Ahmadi, Mohammad Taghi; Razmdideh, Ahmad; Koloor, Seyed Saeid Rahimian; Petrů, Michal
The absence of a band gap in graphene is a hindrance to its application in electronic devices. Alternately, the complete replacement of carbon atoms with B and N atoms in graphene structures led to the formation of hexagonal boron nitride (h-BN) and caused the opening of its gap. Now, an exciting possibility is a partial substitution of C atoms with B and N atoms in the graphene structure, which caused the formation of a boron nitride composite with specified stoichiometry. BC2N nanotubes are more stable than other triple compounds due to the existence of a maximum number of B-N and C-C bonds. This paper focused on the nearest neighbor's tight-binding method to explore the dispersion relation of BC2N, which has no chemical bond between its carbon atoms. More specifically, the band dispersion of this specific structure and the effects of energy hopping in boron-carbon and nitrogen-carbon atoms on the band gap are studied. Besides, the band structure is achieved from density functional theory (DFT) using the generalized gradient approximations (GGA) approximation method. This calculation shows that this specific structure is semimetal, and the band gap energy is 0.167 ev.
Coulomb Blockade Effect in Well-Arranged 2D Arrays of Palladium Nano-Islands for Hydrogen Detection at Room Temperature: A Modeling Study
(MDPI, 2020-01-01) Khaje, Mahdi; Sedghi, Hassan; Goudarzi, Hadi; Taghi Ahmadi, Mohammad; Koloor, Seyed Saeid Rahimian; Petrů, Michal
The fast growth of hydrogen usage as a clean fuel in civil applications such as transportation, space technology, etc. highlights the importance of the reliable detection of its leakage and accumulation under explosion limit by sensors with a low power consumption at times when there is no accumulation of hydrogen in the environment. In this research, a new and efficient mechanism is presented for hydrogen detection—using the Coulomb blockade effect in a well-arranged 2D array of palladium nano-islands—which can operate at room temperature. We demonstrated that under certain conditions of size distribution and the regularity of palladium nano-islands, with selected sizes of 1.7, 3 and 6.1 nm, the blockade threshold will appear in current-voltage (IV) characteristics. In reality, it will be achieved by the inherent uncertainty in the size of the islands in nano-scale fabrication or by controlling the size of nanoparticles from 1.7 to 6.1 nm, considering a regular arrangement of nanoparticles that satisfies single-electron tunneling requirements. Based on the simulation results, the threshold voltage is shifted towards lower ones due to the expansion of Pd nanoparticles exposed to the environment with hydrogen concentrations lower than 2.6%. Also, exploring the features of the presented structure as a gas sensor, provides robustness against the Gaussian variation in nano-islands sizes and temperature variations. Remarkably, the existence of the threshold voltage in the IV curve and adjusting the bias voltage below this threshold leads to a drastic reduction in power consumption. There is also an improvement in the minimum detectable hydrogen concentration as well as the sensor response.
Effects of cell aspect ratio and relative density on deformation response and failure of honeycomb core structure
(IOP PUBLISHING LTD, TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND, 2020-01-01) Khan, Muhammad Salman; Koloor, Seyed Saeid Rahimian; Tamin, Mohd Nasir
The extensive applications of honeycomb (HC) core in sandwich structures necessitates the influence of the cellular geometry and cell wall base material on the mechanical response to be quantified. In this respect, this paper establishes the mechanics of the deformation and the failure processes of the HC core under the out-of-plane compressive, tensile, and shear loading. The corresponding mechanical properties are determined and the mechanisms of failure of the HC core structure are identified. The influence of the relative density (rho*/rho(s)) and the cell aspect ratio (H/c) of the hexagonal HC core on the compressive deformation response, the out-of-plane properties and the characteristic dissipation energy density (DED) of the structure is established. Results show that the compressive strength increases exponentially from 1.5 to 10.6 MPa over the relative density range of 0.028 <= (rho*/rho(s)) <= 0.125. The out-of-plane shear modulus, G(13) and G(23) are 33.9 and 58.2 MPa, while the shear strength, tau(13) and tau(23) are 1.07 and 2.03 MPa, respectively. The HC core with a low aspect ratio (H/c < 2.64) failed due to the early debonding of the double-wall hexagonal cells, while at H/c >= 2.64, by elastic buckling of the cells. A phenomenological model is formulated to highlight the combined effects of both parameters on the compressive strength (sigma(c)) of the HC cores, covering the range of 0.028 <= (rho*/rho(s)) <= 0.056 and 2.5 <= (H/c) <= 5.62. Furthermore, the characteristic dissipation energy density (DED) under the out-of-plane compression varies linearly within the range of 2.5 < (H/c) rho*/rho(s) = 0.056. The HC core with H/c = 3.96, but with twice higher rho*/rho(s) exhibits about twice larger DED. These resulting properties and failure mechanisms of the anisotropic paper-based HC core are useful for the validation of the predictive computational models.
Estimation of Critical Dimensions for the Crack and Pitting Corrosion Defects in the Oil Storage Tank Using Finite Element Method and Taguchi Approach
(MDPI, 2020-01-01) Omidi Bidgoli, Mostafa; Reza Kashyzadeh, Kazem; Koloor, Seyed Saeid Rahimian; Petrů, Michal
Tanks play an important role in storing crude oil. Therefore, the maintenance and service life of tanks are very important for oil companies. In this regard, knowledge on the state of the critical conditions of various existing defects, such as cracks and pitting corrosion defects, can play an essential role in providing a better service to these huge metal structures. In the present research, the basic theories relating to crack defects were discussed. Then, an oil reserve in one of the island states of the country was modeled and analyzed by considering different types of defects using Finite Element (FE) simulation. Next, the critical dimensions of cracks and corrosion holes were identified in a number of cases. Eventually, the Taguchi Approach (TA) was used to investigate the effect of different parameters related to the various defects, such as length, depth and diameter, on the maximum stress. The results indicated that the effect of the crack and pitting corrosion depth is superior to the effect of the length and diameter for defects of crack and pitting corrosion, respectively.
Fabrication of High-Quality Polymer Composite Frame by a New Method of Fiber Winding Process
(MDPI, 2020-05-02) Mlýnek, Jaroslav; Petrů, Michal; Martinec, Tomáš; Koloor, Seyed Saeid Rahimian
Polymer composite frame has been frequently used in the main structural body of vehicles in aerospace, automotive, etc., applications. Manufacturing of complex curved composite frame suffer from the lack of accurate and optimum method of winding process that lead to preparation of uniform fiber arrangement in critical location of the curved frame. This article deals with the fabrication of high-quality polymer composite frame through an optimal winding of textile fibers onto a non-bearing core frame using a fiber-processing head and an industrial robot. The number of winding layers of fibers and their winding angles are determined based on the operational load on the composite structure. Ensuring the correct winding angles and thus also the homogeneity of fibers in each winding layer can be achieved by using an industrial robot and by definition of its suitable off-line trajectory for the production cycle. Determination of an optimal off-line trajectory of the end-effector of a robot (robot-end-effector (REE)) is important especially in the case of complicated 3D shaped frames. The authors developed their own calculation procedure to determine the optimal REE trajectory in the composite manufacturing process. A mathematical model of the winding process, matrix calculus (particularly matrices of rotations and translations) and an optimization differential evolution algorithm are used during calculation of the optimal REE trajectory. Polymer composites with greater resistance to failure damage (especially against physical destruction) can be produced using the above mentioned procedure. The procedure was successfully tested in an experimental composite laboratory. Two practical examples of optimal trajectory calculation are included in the article. The described optimization algorithm of REE trajectory is completely independent of the industrial robot type and robot software tools used and can also be used in other composite manufacturing technologies.
Isolation and Characterization of a Novel Bacterium from the Marine Environment for Trichloroacetic Acid Bioremediation
(MDPI, 2020-07-02) Heidarrezaei, Mahshid; Shokravi, Hoofar; Huyop, Fahrul; Koloor, Seyed Saeid Rahimian; Petrů, Michal
Halogenated compounds are an important class of environmental pollutants that are widely used in industrial chemicals such as solvents, herbicides, and pesticides. Many studies have been carried out to explore the biodegradation of these chemicals. Trichloroacetic acid (TCA) is one of the main halogenated compounds that are carcinogenic to humans and animals. The bacterium was isolated from the northern coastline of Johor Strait. In this study, the ability of strain MH2 to biodegrade TCA was evaluated by a growth experiment and dehalogenase enzyme assay. The growth profile of the isolated strain was examined. The doubling time for L. boronitolerans MH2 was found to be 32 h. The release of chloride ion in the degradation process was measured at 0.33 × 10−3 ± 0.03 mol∙L-1 after 96 h when the growth curve had reached its maximum within the late bacterial exponential phase. The results showed that the strain had a promising ability to degrade TCA by producing dehalogenase enzyme when cell-free extracts were prepared from growth on TCA as the sole carbon source with enzyme-specific activity, 1.1 ± 0.05 µmolCl-min−1∙mg−1 protein. Furthermore, the morphological, and biochemical aspects of the isolated bacterium were studied to identify and characterize the strain. The morphological observation of the isolated bacterium was seen to be a rod-shaped, Gram-positive, motile, heterotrophic, and spore-forming bacterium. The amplification of the 16S rRNA and gene analysis results indicated that the isolated bacterium had 98% similarity to Lysinibacillus boronitolerans. The morphological and biochemical tests supported the 16S rRNA gene amplification. To the best of the authors’ knowledge, this is the first reported case of this genus of bacteria to degrade this type of halogenated compound.
Nano-level damage characterization of graphene/polymer cohesive interface under tensile separation
(MDPI, 2019-01-01) Koloor, Seyed Saeid Rahimian; Rahimian-Koloor, S. M.; Karimzadeh, A.; Hamdi, M.; Petrů, Michal; Tamin, M. N.
The mechanical behavior of graphene/polymer interfaces in the graphene-reinforced epoxy nanocomposite is one of the factors that dictates the deformation and damage response of the nanocomposites. In this study, hybrid molecular dynamic (MD) and finite element (FE) simulations of a graphene/polymer nanocomposite are developed to characterize the elastic-damage behavior of graphene/polymer interfaces under a tensile separation condition. The MD results show that the graphene/epoxy interface behaves in the form of elastic-softening exponential regressive law. The FE results verify the adequacy of the cohesive zone model in accurate prediction of the interface damage behavior. The graphene/epoxy cohesive interface is characterized by normal stiffness, tensile strength, and fracture energy of 5 × 10-8 (aPa·nm-1), 9.75 × 10-10 (nm), 2.1 × 10-10 (N·nm-1) respectively, that is followed by an exponential regressive law with the exponent, α = 7.74. It is shown that the commonly assumed bilinear softening law of the cohesive interface could lead up to 55% error in the predicted separation of the interface.
On the Performance of Small-Scale Horizontal Axis Tidal Current Turbines. Part 1: One Single Turbine
(MDPI, 2020-01-01) Alipour, Ramin; Alipour, , Roozbeh; Koloor, Seyed Saeid Rahimian; Petrů, Michal; Ghazanfari, Seyed Alireza
The blade number of a current tidal turbine is one of the essential parameters to increase the stability, performance and efficiency for converting tidal current energy into rotational energy to generate electricity. This research attempts to investigate the effect of blade number on the performance of a small-scale horizontal tidal current turbine in the case of torque, thrust coefficient and power coefficient. Towards this end and according to the blade element momentum theory, three different turbines, i.e., two, three and four-bladed, were modeled using Solidworks software based on S-814 airfoil and then exported to the ANSYS-FLUENT for computational flow dynamics (CFD) analysis. SST-K-ω turbulence model was used to predict the turbulence behavior and several simulations were conducted at 2 ≤ tip speed ratio ≤ 7. Pressure contours, turbulence kinetic energy contours, cut-in-speed-curves, and streamlines around the blades and rotors were extracted and compared to provide an ability for a deep discussion on the turbine performance. The results show that in the case of obtainable power, the optimal value of tip speed ratio is around 5, so that the maximum power was achieved for the four-bladed turbine. Out of optimal condition, higher blade number and lower blade number turbines should be used at less than and greater than the optimal values of tip speed ratio, respectively. The results of simulations for the three-bladed turbine were validated against the experimental data with good agreement.
The Effect of Lateral Load Type on Shear Lag of Concrete Tubular Structures with Different Plan Geometries
(MDPI, 2020-01-01) Moghadasi, Mostafa; Taeepoor, Soheil; Koloor, Seyed Saeid Rahimian; Petrů, Michal
Tubular structures are extensively recognized as a high efficiency and economically reasonable structural system for the design and construction of skyscrapers. The periphery of the building plan in a tubular system consists of closely spaced columns connected by circumferential deep spandrels. When a cantilever tube is subjected to a lateral load, it is expected that the axial stress in each column located in the flange frame of the tube is the same, but because of the flexibility of peripheral beams, the axial stress in the corner columns and middle columns is distributed unequally. This anomaly is called “shear lag”, and it is a leading cause of the reduction in efficiency of the structure. In this paper, the possible relation between shear lag and the type of lateral load subjected to these systems is investigated. The above relation is not yet considered in previous literatures. Three various plan shapes including rectangular, triangular and hexagon were modeled, analyzed, designed and subjected to the earthquake and wind load, separately. Further work is carried out to compare the shear lag factor of these structures with distinct plan shapes against different types of lateral load. It is observed that all types of structures with various plan geometry subjected to the wind load had a greater amount of shear lag factor in comparison with structures subjected to the static and dynamic earthquake loads. In addition, shear lag in structures with the hexagon shaped plan was at the minimum.
Using Finite Element Approach for Crashworthiness Assessment of a Polymeric Auxetic Structure Subjected to the Axial Loading
(MDPI, 2020-06-09) Nejad, Ali Farokhi; Alipour, Roozbeh; Rad, Mozafar Shokri; Yahya, Mohd Yazid; Koloor, Seyed Saeid Rahimian; Petrů, Michal
Polyurethane foams are one of the most common auxetic structures regarding energy absorption enhancement. This present study evaluates the result reliability of two different numerical approaches, the H-method and the P-method, to obtain the best convergence solution. A polymeric re-entrant cell is created with a beam element and the results of the two different methods are compared. Additionally, the numerical results compare well with the analytical solution. The results show that there is a good agreement between converged FE models and the analytical solution. Regarding the computational cost, the P-method is more efficient for simulating the re-entrant structure subjected to axial loading. During the second part of this study, the re-entrant cell is used for generating a polymeric auxetic cellular tube. The mesh convergence study is performed on the cellular structures using the H- and P- methods. The cellular tube is subjected to tensional and compressive loading, the module of elasticity and Poisson’s ration to calculate different aspect ratios. A nonlinear analysis is performed to compare the dynamic response of a cellular tube versus a solid tube. The crashworthiness indicators are addressed and the results are compared with equivalent solid tubes. The results show that the auxetic cellular tubes have better responses against compressive loading. The primary outcome of this research is to assess a reliable FE approach for re-entrant structures under axial loading.
Vehicle-Assisted Techniques for Health Monitoring of Bridges
(MDPI, 2020-06-19) Shokravi, Hoofar; Shokravi, Hooman; Heidarrezaei , Mahshid; Koloor, Seyed Saeid Rahimian; Petrů, Michal
Bridges are designed to withstand different types of loads, including dead, live, environmental, and occasional loads during their service period. Moving vehicles are the main source of the applied live load on bridges. The applied load to highway bridges depends on several traffic parameters such as weight of vehicles, axle load, configuration of axles, position of vehicles on the bridge, number of vehicles, direction, and vehicle’s speed. The estimation of traffic loadings on bridges are generally notional and, consequently, can be excessively conservative. Hence, accurate prediction of the in-service performance of a bridge structure is very desirable and great savings can be achieved through the accurate assessment of the applied traffic load in existing bridges. In this paper, a review is conducted on conventional vehicle-based health monitoring methods used for bridges. Vision-based, weigh in motion (WIM), bridge weigh in motion (BWIM), drive-by and vehicle bridge interaction (VBI)-based models are the methods that are generally used in the structural health monitoring (SHM) of bridges. The performance of vehicle-assisted methods is studied and suggestions for future work in this area are addressed, including alleviating the downsides of each approach to disentangle the complexities, and adopting intelligent and autonomous vehicle-assisted methods for health monitoring of bridges.

Browsing by Author "Koloor, Seyed Saeid Rahimian"

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