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Showing papers in "Microsystem Technologies-micro-and Nanosystems-information Storage and Processing Systems in 2018"


Journal ArticleDOI
TL;DR: Comparison and robustness analysis of grey wolf optimization based fractional order proportional–integral derivative (FOPID) controller for speed control of DC motor shows that proposed approach with ITAE as an objective function gives less settling, rise times and comparable overshoot in comparison to existing approaches in the literature.
Abstract: The present work deals with comparative and robustness analysis of grey wolf optimization (GWO) based fractional order proportional–integral derivative (FOPID) controller for speed control of DC motor. The GWO is a meta-heuristic algorithm inspired from the social hunting behaviour of grey wolves as search agents. The GWO algorithm maintains a proper balance between exploration and exploitation processes. The integral of time multiplied absolute error (ITAE) has been taken as an objective function for obtaining the parameters of FOPID controller by GWO. Comparison of proposed GWO/FOPID approach with other existing techniques has also been shown along with GWO/PID. It has been observed that proposed approach with ITAE as an objective function gives less settling, rise times and comparable overshoot in comparison to existing approaches in the literature. The robustness analysis of GWO/FOPID approach has also been carried out with variations in the parameters of DC motor.

68 citations


Journal ArticleDOI
TL;DR: The fuzzy ant colony optimization (FACO) method proposed in this paper minimizes the iterative learning error of the ant colony optimized algorithm using fuzzy control and can find the shortest path and avoid obstacles for both simple and complex topographies.
Abstract: The fuzzy ant colony optimization (FACO) method proposed in this paper minimizes the iterative learning error of the ant colony optimization (ACO) algorithm using fuzzy control. This algorithm finds the shortest path, detects any obstructions in front of the mobile robot using ultrasonic transducers, and adjusts the turning angle of the mobile robot so as to avoid obstacles. To verify the FACO algorithm, simulations using a mobile robot in two environments were carried out. The first environment was shortest-path planning without obstacles. The second environment was shortest-path planning for a single destination with obstacles. This paper also compares tests carried out in a simple Z-shaped environment map and in a complicated environment map. By comparing FACO with a pattern search (PS) algorithm, a genetic algorithm (GA), particle swarm optimization (PSO), and traditional ACO for the cases in the simple Z-shaped environment map, we found that the path distance obtained using FACO was 2.60, 4.40, 2.04, and 6.53% shorter than that using PS, GA, PSO, and ACO, respectively. In the complex environment map, as compared to the self-adaptive ant colony optimization, FACO had a path distance that was 1.38% shorter. Therefore, the results showed that the FACO algorithm can find the shortest path and avoid obstacles for both simple and complex topographies.

62 citations


Journal ArticleDOI
TL;DR: In this article, the authors focus on computational and experimental analysis of a simple serpentine microchannel without obstacles and an SMC with semicircular obstacles of different sizes, and the effect of obstacle size on pressure drop and mixing length for achieving index 1 is analyzed.
Abstract: This paper focuses on computational and experimental analysis of a simple serpentine microchannel without obstacles and serpentine microchannel with semicircular obstacles of different sizes. The work has been performed in three phases- computational analysis, experimentation and flow physics study. The 3D models of a simple serpentine microchannel (without obstacles) and serpentine microchannels with semicircular obstacles (with radius as 50, 100, 150 and 200 µm) have been developed using COMSOL Multiphysics software. The effect of obstacle size on pressure drop and mixing length for achieving index 1 has been analyzed. A simple serpentine qmicrochannel and a serpentine microchannel with 150 µm radius semicircular obstacles have been fabricated with polydimethylsiloxane using soft lithography process. The experimental analysis for pressure drop as well as mixing index has been performed. A good agreement has been observed between experimental and computational results. The validated computational model is then used to study the mixing index for the same microchannels for different flow conditions, i.e. for different Reynolds numbers. The mixing lengths are observed to be lesser for Re 0.28 and 30. Further, the effect of diffusion and generation of secondary flow due to advection on mixing length for the considered Reynolds numbers are analyzed through the flow physics study.

62 citations


Journal ArticleDOI
TL;DR: This paper proposes a novel super-twisting PID sliding mode controller using a multi-objective optimization bat algorithm (MOBA-STPIDSMC) for the control of a MEMS gyroscope using a metaheuristic method for optimal design of the MEMS Gyroscope in order to tune the parameter of the proposed controller.
Abstract: This paper proposes a novel super-twisting PID sliding mode controller (STPIDSMC) using a multi-objective optimization bat algorithm (MOBA-STPIDSMC) for the control of a MEMS gyroscope. In order to enhance the robustness of the control system, a sliding surface based on PID controller is designed. The chattering phenomenon in PID sliding mode control (PIDSMC) which is usually caused by the excitation of fast unmodelled dynamic is the main problem. The chattering phenomenon will be removed by using super-twisting control. A metaheuristic method, the multi-objective bat algorithm (MOBA) is applied for optimal design of the MEMS gyroscope in order to tune the parameter of the proposed controller. The performance of the MOBA-STPIDSMC is compared with four other controllers such as sliding mode control (SMC), PIDSMC, STPIDSMC and a single objective bat algorithm super-twisting PID sliding mode controller (BA-STPIDSMC). Numerical simulations clearly confirmed the effectiveness of the proposed controller.

61 citations


Journal ArticleDOI
TL;DR: In this paper, a passive planar micromixer with circular and square mixing chambers is proposed to operate in the laminar flow regime for high mixing index, which can be used in microfluidic systems which require fast mixing at Re less than 1 and greater than 15.
Abstract: In this paper, passive planar micromixers based on circular and square mixing chambers spaced at equidistant along the length of micromixer are proposed to operate in the laminar flow regime for high mixing index. Numerical simulations are conducted to evaluate the performance of proposed micromixers by solving the Navier–Stokes equation and convection–diffusion equation. A COMSOL Multiphysics 5.0 is used for computational fluid dynamics. Numerical simulation of mixing of fluids in a micromixer with circular and square chambers in a laminar flow regime has been carried out. Four performance parameters namely, mixing index, pressure drop, pumping power, and performance index are used to evaluate different design configurations of micromixers. Analysis of mixing index based on the standard deviation of the mass fraction is carried with different constriction channel width such as 200, 250, and 300 µm for a range of Reynolds number from 0.1 to 75. The both micromixers show over 95% mixing at the exit for the range 15–75 of Reynolds number at constriction width of 200 µm. Especially, about 99% mixing is achieved at Reynolds number less than one i.e. at 0.1. The effect of Reynolds number on the pressure drop is also investigated. Thus, the proposed micromixers can be used in microfluidic systems which require fast mixing at Re less than 1 and greater than 15.

60 citations


Journal ArticleDOI
TL;DR: In this paper, the relationship between electrical shocking in terms of frequency and peak to peak voltage at variable thermo-mechanical shocking conditions has been developed and analyzed, and the variable frequency shocking represented one of the most important parameter to characterize and design the piezoelectric material, especially when it relates to design of intelligent structures for aerospace industry.
Abstract: Piezoelectric materials are widely used as smart structure in various aerospace applications as they can generate voltage, store charge and drive microelectronics directly because of its ability to sense, actuate and harvest energy. It is a well known phenomenon in terms of the linear electromechanical interaction between mechanical and electrical state. It is actively used in aerospace structural health monitoring, due to the high stiffness and drive capacity depending on the voltage, widespread mechanical properties and their interactions. In this research work Barium Titanate ( $$BaTiO_3$$ ) is shocked by variable mechanical loading under different thermal and electrical shocking conditions for behavior analysis. A test rig is constructed on the basis of equivalent circuit method to perform experimentation. The relationship between electrical shocking in terms of frequency and peak to peak voltage at variable thermo-mechanical shocking conditions has been developed and analyzed. The variable frequency shocking represented one of the most important parameter to characterize and design the piezoelectric material, especially when it relates to design of intelligent structures for aerospace industry. Effect of thermo mechanical loading, frequency and resistance to peak to peak voltage is predicted experimentally and numerically. Abaqus is used for numerical simulations. Numerical model constructed for $$BaTiO_3$$ in this research predicts the actual behavior for voltage generation with accuracy of 10%.

58 citations


Journal ArticleDOI
TL;DR: This study proposes an efficient 4:2 compressor for approximate computing in the nano era using FinFET as a current industrial technology and QCA as a promising emerging nanodevice, which leads to circuit efficiency and lower energy consumption.
Abstract: Approximate computing is an effective paradigm for energy-efficient hardware design in nanoscale. In this study, an efficient 4:2 compressor for approximate computing in the nano era is proposed. The proposed design includes only two majority gates instead of AND-OR and XOR logics, which leads to circuit efficiency and lower energy consumption. Moreover, the majority operator is the natural logic primitive for several beyond-CMOS technologies such as quantum-dot cellular automata (QCA). The proposed approach is designed using FinFET as a current industrial technology and QCA as a promising emerging nanodevice. FinFETs show lower short channel effects and provide excellent electrostatic characteristics than bulk CMOS for sub-32 nm technologies. Furthermore, QCA will provide extremely high-density and energy-efficient digital circuits for the future VLSI design. In order to evaluate the performance of the proposed approach and make comparisons with the previous designs, extensive simulations are performed using HSPICE, QCADesigner and QCAPro tools. In addition, the proposed compressor is utilized efficiently in image processing applications and the critical metrics in measuring the quality of images are evaluated using MATLAB. The results indicate significant improvements in terms of different performance and accuracy metrics in comparison with the most efficient designs previously presented in the literature.

55 citations


Journal ArticleDOI
TL;DR: In this article, a magnetorheological (MR) fluids based haptic interface has been developed in master site to provide the haptic sensation to the interventionalist during endovascular tele-surgery.
Abstract: In this paper, a magnetorheological (MR) fluids based haptic interface has been developed in master site to provide the haptic sensation to the interventionalist during endovascular tele-surgery. The novel design of haptic interface allows the interventionalist to apply conventional axial and radial motions to a rigid catheter which goes through the MR fluids. In addition, the haptic feedback in the axial direction can be generated by altered the viscosity of MR fluids. The actual force measurement is provided to assess the effectiveness of this haptic feedback. While to evaluate the performance of this master device, the virtual-reality (VR) simulator is as the slave side to execute the replicated motions, pull, push and twist of the virtual catheter, which is applied by interventionalist in master site. The ten operators are recruited to navigate a catheter through virtual cerebral-vessel. Experimental results indicate that the use of the proposed haptic interface has a benefit to avoiding the collision and improving the safety of endovascular tele-surgery.

53 citations


Journal ArticleDOI
TL;DR: In this paper, a mathematical model of two-temperature phase-lag Green-Naghdi thermoelasticty theories based on fractional derivative heat transfer is given, where the resulting non dimensional coupled equations together with the Laplace transforms techniques are applied to a specific problem of a half space subjected to arbitrary heating which is taken as a function of time.
Abstract: A mathematical model of two-temperature phase-lag Green–Naghdi thermoelasticty theories based on fractional derivative heat transfer is given. The GN theories as well as the theories of coupled and of generalized thermoelasticity with thermal relaxation follow as limit cases. The resulting non dimensional coupled equations together with the Laplace transforms techniques are applied to a specific problem of a half space subjected to arbitrary heating which is taken as a function of time and is traction free. The inverse transforms are obtained by using a numerical method based on Fourier expansion techniques. The predictions of the theory are discussed and compared with those for the generalized theory of thermoelasticity with one relaxation time. The effects of temperature discrepancy and fractional order parameters on copper-like material are discussed in different types of GN theories.

52 citations


Journal ArticleDOI
TL;DR: A three-level fault-tolerant ALU based on QCA is discussed in this paper, which performs “AND’, “OR”, ‘XOR’ and “Full adder” and has high fault tolerance compared to the similar methods according to the simulation results using QCAdesigner.
Abstract: Quantum-dot cellular automata (QCA) as a technology in the nanoscale is used for designing the future circuits. It has high density, speed, and low power dissipation. Besides, arithmetic and logic unit (ALU) is one of the main bases to define the system performance. Its plan depends on combinational circuits that decrease complexity and it has reasonable simulation times. Cell misalignment, cell displacement, cell omission (missing cell), and the extra (additional) cell are considered as the weaknesses of these circuits. Designing Fault tolerance of ALU in QCA is very important but there is no survey about the details. A three-level fault-tolerant ALU based on QCA is discussed in this paper, which performs “AND”, “OR”, “XOR” and “Full adder”. Also, the used rotated majority gate in the proposed ALU is fault tolerance. This structure tolerances a single stuck-at 0 and 1 and related faults are covered using test patterns {11100, 11101, 11010, 11001}. Furthermore, the presented ALU, under omission errors of cells in layers 2 and 3 is tolerated using the test patterns. The presented method has high fault tolerance compared to the similar methods according to the simulation results using QCAdesigner. It also has 0.78 µm2 of circuit area and the outputs are delivered after three clock cycles. Also, it has lower area consumption and delay compared to other schemes.

51 citations


Journal ArticleDOI
TL;DR: In this paper, an enzyme-less glutamate sensor based on nickel oxide modified glassy carbon electrode is presented. But, the sensor displays a fast response time of < 5 s and a linear dependency of R2 0.997 for glutamate concentration of up to 8mM at an applied potential of + 0.55 V with a sensitivity of 11µA/mM−1/cm−2 and a detection limit of 272μM.
Abstract: This work reports an enzyme-less glutamate sensor based on nickel oxide modified glassy carbon electrode. The nanoparticles of NiO were synthesized by sol–gel method, and showed high electro-catalytic activity towards glutamate oxidation in 0.1 M NaOH solution. The sensor displays a fast response time of < 5 s and a linear dependency of R2 0.997 for glutamate concentration of up to 8 mM at an applied potential of + 0.55 V with a sensitivity of 11 µA mM−1 cm−2 and a detection limit of 272 μM (S/N = 3). The interference studies of NiO/GC electrode showed a significant current response for glutamate in the presence of uric acid and ascorbic acid. Thereby, this simple NiO nanoparticle based sensor can be promising platform for the development of a robust enzymeless glutamate sensor.

Journal ArticleDOI
TL;DR: In this article, a cylindrical functionally graded shell model is developed in the framework of nonlocal strain gradient theory for the first time, and its equations of motion and corresponding boundary conditions are derived by Hamilton's principle and the first-order shear deformation theory.
Abstract: In this article, a cylindrical functionally graded shell model is developed in the framework of nonlocal strain gradient theory for the first time. For this purpose, the modeled cylindrical FG nanoshell, its equations of motion and corresponding boundary conditions are derived by Hamilton’s principle and the first-order shear deformation theory. Generalized differential quadrature method is applied to discretize the equations of motion. The results of the proposed model are compared with those of the Eringen’s nonlocal, strain gradient, modified couple stress and classical theories. The conclusion of this comparison is that the nonlocal strain gradient theory combines advantages of nonlocal and strain gradient theories by applying both material length scale parameter and a nonlocal parameter in the model to consider the significance of strain gradient stress field and nonlocal elastic stress field, respectively. Furthermore, the effects of the material length scale, nonlocal parameter, FG power index, circumferential wave numbers and length of shell on vibrational behavior of the nonlocal strain gradient FG nanoshell for simply supported and clamped–clamped boundary conditions are investigated.

Journal ArticleDOI
TL;DR: In this paper, the authors report on electromechanical, switching time and performance analysis of capacitive shunt RF MEMS switch with uniform and non-uniform meanders.
Abstract: This paper reports on electromechanical, switching time and performance analysis of capacitive shunt RF MEMS switch with uniform and non-uniform meanders. The MEMS switch is a freely moving membrane over coplanar wave guide. Electromechanical analysis is done for movable beam with gold as material and dielectric as Si3N4 and HfO2. For these dielectric materials pull in voltage is 2.3 and 2 V respectively with beam thickness of 0.8 µm by using COMSOL FEM Tool. Si3N4 with dielectric constant of 7.6 gives Cratio of 8.69 and 11.13 for 0.8 and 0.6 μm of beam thickness respectively. RF performance analysis is done by using HFSS software and the simulation results states that non uniform single meander has return loss as −60 dB, insertion loss −0.2 dB and isolation loss −14 dB at 20 GHz frequency and uniform 3 meander switch has return loss as −55 dB. Switching time analysis is done by using MATLAB. For uniform three meander it is 0.12 ms and for non-uniform one meander beam it is 0.7 ms. Whereas use of HfO2 with dielectric constant of 14 as dielectric gives Cratio of 14.93 and 19.66 for 0.8 and 0.6 μm of beam thickness respectively with gap between the electrode beam and dielectric as 0.8 μm.

Journal ArticleDOI
TL;DR: In this article, the authors used microfluidic pore models to study the migration of fine particles and the bridging/clogging behavior in a structure mimicking porous media.
Abstract: Fine particles within porous media may migrate with the flowing fluid and cause bridging or clogging in the pore space. Bridging and clogging reduce the flow permeability of porous media, which has a significant influence on petroleum engineering applications such as water and oil extraction, sand production, and gas production from hydrate-bearing sediments. Although the migration of fine particles and its impact on bridging and clogging have been investigated for a single-phase flow, it has not been understood clearly for a multi-phase flow. This work reports an approach using microfluidic pore models to study the migration of fine particles and the bridging/clogging behavior in a structure mimicking porous media. Results from the microfluidic model show that: (1) fine particles accumulated along the water and gas (CO2) interface; (2) fine particle concentrations in pores locally increased due to the accumulated particles at the interface, and (3) consequently bridging and clogging occurred in the pore throat. Findings from this work provide a starting point in understanding complex phenomena including a reduced flow permeability of porous media on a fluid containing fine particles for a variety of petroleum engineering applications.

Journal ArticleDOI
Hongwen Sun1, Yin Minqi1, Wangtong Wei1, Li Jiacheng1, Wang Haibin1, Jin Xin1 
TL;DR: This contribution reviews the state-of-the-art development of different energy harvesting sources including mechanical, light/solar, wind, sound, RF, biomechanical and pyroelectric energy for IoT applications: sensors, wearables, and RF-MEMS.
Abstract: The Internet of Things (IoT) can manage a large number of smart wireless devices and form a networking infrastructure connected to the Internet. Traditional batteries in IoT produce environmental concerns and have limited operational life. Harvesting and converting ambient environmental energy is an effective and important approach for sustainable green power used in wireless and portable devices in IoT. This contribution reviews the state-of-the-art development of different energy harvesting sources including mechanical, light/solar, wind, sound, RF, biomechanical and pyroelectric energy. Power density generated from ambient source ranges widely from 0.001 μW/cm2 (RF WiFi) to 100 mW/cm2 (outdoor solar). Depends on application areas and working principles, typical power consumptions of IoT sensor nodes are in the order of mW (1---750 mW) in active mode and μW (0---60 μW) in sleep mode (Mathna et al. in Talanta 75:613---623, 2008; Magno et al. in IEEE Trans Ind Electron 61:1871---1881, 2014; Baranov et al. in Sens Actuators A 233:279---289, 2015; Somov et al. in Procedia Eng 87:520---523, 2014; Spirjakin et al. in Sens Actuators A 247:247---253, 2016; Samson et al. in Sens Actuators A 172:240---244, 2011). Therefore, efficient energy storage and management strategies are important for IoT development. These parts are discussed in order to provide the sustainable power. MEMS based energy harvesting devices may be widely employed in various areas, such as military monitoring, remote weather station, bluetooth headsets, and environment detection. This review focuses on the low power and self powered IoT applications: sensors, wearables, and RF-MEMS. With the advance of nanofabrication techniques, IoT devices will become smaller and enter into the era of Internet of Nano-Things.

Journal ArticleDOI
TL;DR: In this paper, the design and simulation of uniform structured RF MEMS capacitive shunt switch using FEM tool and HFSS software is presented. And the results showed that the rectangular perforations gave the better results, when compared with square and cylindrical shaped perfations.
Abstract: This paper presents design and simulation of uniform structured RF MEMS capacitive shunt switch using FEM tool and HFSS software. The switches with different shaped meanders and perforations which result in less spring constant, less pull-in voltage, high isolation loss, high switching speed and low insertion loss have been designed. From the simulated results it is observed that the rectangular perforations gives the better results, when compared with square and cylindrical shaped perforations. Comparative study is done for zigzag, plus and three square shaped meander along with rectangular perforations on each structure. When the gap between the dielectric and the movable beam is 0.8 µm, the up state capacitance for HfO2 is 4.06fF and for Si3N4 is 3.80fF. The downstate capacitance for HfO2, Si3N4 is 49fF, 26.9fF respectively. The capacitance ratio is 120.6. Poly-tetra-fluoro-ethylene material is given for the movable beam whose young’s modulus is 0.4 GPa and the spring constant is calculated theoretically for each structure; by using this the pull in voltage and the settling time are calculated. Step switch with three square Meander has switching time 10.25 µs, pull in voltage as 2.45 V. By using HFSS 3-D electromagnetic model we observed the return loss (S11) is less than −60 dB, the insertion loss is less than −0.07 dB in the range of 1–40 GHz frequency and switch isolation (S21) is −61 dB at 28 GHz frequency.

Journal ArticleDOI
TL;DR: In this paper, an FEM model based on the Galerkin method for analyzing elastic stress field in a platelet reinforced composite subjected to axial load was developed and validated using analytical 3D and shear-lag models and ANSYS results.
Abstract: In this study, An FEM model was developed based on the Galerkin method for analyzing elastic stress field in a platelet reinforced composite subjected to axial load. The end of platelets were bonded to the matrix and the unit cell method was utilized to model the composite. Special boundary conditions were applied to the unit cell model. The FEM model developed according the Galerkin method for composite unit cell and then MATLAB software was used for the calculation of displacements, forces, strains and stresses on nodes. The obtained numerical results were then validated using analytical 3D and shear-lag models and ANSYS results. Then, composite elastic modulus was obtained and the effects of platelet volume fraction and aspect ratio on composite elastic modulus, platelet and matrix axial stress and interface shear stress were investigated.

Journal ArticleDOI
Yongqing Xu1, Ying Tian, Binzhen Zhang1, Junping Duan1, Li Yan 
TL;DR: In this paper, a novel radio-frequency micro electromechanical system (RF MEMS) switch on the frequency reconfigurable antenna application was designed, analyzed, and simulated using ANSYS.
Abstract: This paper presents the design, analysis, simulation of a novel radio-frequency micro electromechanical system (RF MEMS) switch on the frequency reconfigurable antenna application. The switch uses coplanar waveguide transmission line for signal transmission, which designed with special mechanical structures, the size of the switch beam is 320 × 120 μm2. The design of RF MEMS switch was simulated using ANSYS. Its simulation voltage is 14 V for 1 µm beam thickness. The electromagnetic performance is optimized and computed by ANSYS EM software. The switch working bandwidth is 40 GHz, the insertion loss is 0.1 dB, return loss of 30 dB and isolation of 26 dB over 30 GHz. In the frequency band, the isolation degree more than 15 dB, and the maximum isolation is 45.3 dB. The switch is mounted on the antenna, and the frequency of the antenna can be reconstructed by using ANSYS EM simulation.

Journal ArticleDOI
TL;DR: In this article, two torsional springs are attached to a single-walled carbon nanotube at both ends to obtain a coefficient matrix for eigen-value analysis involving the Torsional spring coefficients.
Abstract: In the current study, torsional vibration analysis of carbon nano tubes with general elastic boundary conditions is presented via modified couple stress theory. The model developed based on modified couple stress theory gives us opportunity to interpret small size effect. Two torsional springs are attached to a single-walled carbon nanotube at both ends. The idea of the proposed work is to obtain a coefficient matrix for eigen-value analysis involving the torsional spring coefficients. Stoke transformation is employed to work out the Fourier sine series for the carbon nanotube with general elastic boundary conditions. The direct expressions of the vibrational responses with torsional spring coefficients are obtained by using the non classical boundary conditions. In order to demonstrate the validity of the proposed method, results obtained for rigid boundary cases are presented for a comparison with those given in the literature and the results agree with each other exactly. The influences of torsional spring coefficients and small scale parameter on torsional frequencies are investigated in terms of the numerical results for both rigid and restrained boundary conditions.

Journal ArticleDOI
TL;DR: In this paper, a vibration energy harvester with wideband auto-tunable resonant frequency for increased output is designed, which works on the principle of change in center of gravity (CoG) of proof mass that leads to change the natural frequency of the device.
Abstract: Energy harvesters are preferred for enhancing the life of IoT nodes. In this paper, a vibration energy harvester with wideband auto-tunable resonant frequency for increased output is designed. With a variation in frequency of vibrating source, harvested energy reduces to zero value. To harvest the energy on regular basis from the vibrating source, tuning is required. This problem is resolved with the proposed design, which works on the principle of change in centre of gravity (CoG) of proof mass that leads to change the natural frequency of the device. The design is simulated and the static change in frequency with a change in CoG is analytically calculated. The simulated results are verified with fabricated device and similar outcome with boosted bandwidth is obtained. Frequency range is obtained between 22–35 Hz for fabricated device with $$\approx$$ 6.0 V $$_{pp}$$ voltage output for different positions of cylinders.

Journal ArticleDOI
TL;DR: In this article, different layers of an organic light emitting diode (OLED) have been analyzed to analyze the impact of each layer on the performance of the device and showed that hole and electron block layer are instrumental in improving the device luminescence performance and efficiency.
Abstract: This paper explores how different layers in an organic light emitting diode (OLED) impacts its performance. Here, different layers of OLED similar to hole/electron injection layer, transport layer, and block layers are analyzed. Four experimental devices are taken into consideration and their results are compared to one over another to analyze the impact of every layer. Inside depth analysis is also performed on the device to inspect what really is happening Innermost of the OLED. It is noticed that hole and electron block layer are instrumental in improving the device luminescence performance and efficiency. There is an improvement of 16, 37 and 38% in the luminescence of the device when hole block layers and electron block layers are added. Internal device analysis reveals that increase in charge carrier concentration and carrier confinement are the reason for this improvement.

Journal ArticleDOI
TL;DR: In this paper, the size-dependent bending response of functionally graded piezoelectric (FGP) microplates resting on two-parameter elastic foundations and subjected to an external mechanical load, electric voltage and elevated temperature is investigated.
Abstract: In this paper, the size-dependent bending response of functionally graded piezoelectric (FGP) microplates resting on two-parameter elastic foundations and subjected to an external mechanical load, electric voltage and elevated temperature is investigated. The thermo-electro-mechanical loads are presumed uniformly distributed on the upper surface of the plate. To capture the size effect, the modified couple stress theory is employed. In this theory, the couple stress tensor is symmetric and it contains only one material length scale parameter. Based on a four-variable shear deformation plate theory, the governing equations are derived from Hamilton principle, which does not involve only the strain tensor but also the curvature tensor and electric field. The electrical and elastic properties of the microplate are assumed to be graded through the thickness of the plate according to a power law distribution as a function of the volume fraction of the constituents. The effects of the geometrical parameters (material length scale parameter, side-to-thickness ratio and plate aspect ratio), gradient index, electric voltage, elastic foundation stiffness and temperature parameters on the deflection, electric potential, stresses and electric displacements of the FGP microplates are all presented and discussed.

Journal ArticleDOI
TL;DR: In this paper, an inkjet printed ultra-wideband (UWB) flexible antenna on photo paper is presented. And the antenna pattern comprises a circular patch with the double stepped symmetric ground plane and is fed by a coplanar waveguide (CPW) technique on one-sided photo paper.
Abstract: In order to keep pace with the growing research and development on flexible and reconfigurable electronics, this research presents an inkjet printed ultra-wideband (UWB) flexible antenna on photo paper. The antenna pattern comprises a circular patch with the double stepped symmetric ground plane and is fed by a coplanar waveguide (CPW) technique on one-sided photo paper. The system is designed, simulated, fabricated, and tested experimentally. It operates over 3.2–30 GHz (161% fractional bandwidth, FBW) range with a return loss of − 10 dB or less and a voltage standing wave ratio (VSWR) < 2. The proposed monopole antenna is of dimensions 33.1 mm × 32.7 mm × 0.254 mm with an electrical size of 0.35 λ × 0.35 λ at 3.2 GHz frequency. This design exhibits nearly omnidirectional radiation pattern over the entire impedance bandwidth. An average gain of 4.87 and a radiation efficiency of 86.61% was observed. The miniature size, higher operating range, relatively constant radiation pattern along with higher acceptable peak gain of the antenna on a paper substrate lend itself to wearable and Internet of Things (IoT) applications.

Journal ArticleDOI
TL;DR: In this paper, the sensitivity performance of functionally graded magneto-electro-elastic (FG-MEE) nanoplate with attached nanoparticles as a nanosensor is analyzed based on nonlocal Mindlin plate assumption.
Abstract: In the current paper, the sensitivity performance of functionally graded magneto-electro-elastic (FG-MEE) nanoplate with attached nanoparticles as a nanosensor is analyzed based on nonlocal Mindlin plate assumption. Power law distribution model is employed to display how the material properties of FG-MEE nanoplate vary across the thickness direction. It is supposed that FG-MEE nanoplate is under initial external electric and magnetic potentials. Boundary condition of each edge of FG-MEE nanoplate is assumed to be simply supported. Furthermore, a Pasternak substrate is applied for modelling the total reaction pressure between nanoplate and foundation. Partial differential equations and corresponding boundary conditions are first achieved using Hamilton’s variational principle and then analytically solved to determine the frequency shift utilizing Navier’s approach. Numerical examples are performed to elucidate the dependency of the sensitivity performance of FG-MEE nanosensor on the volume fraction exponent, nonlocal parameter, total attached mass and location of the nanoparticle, aspect ratio, mode number, initial external electric voltage, initial external magnetic potential, and Pasternak medium coefficients. It is clearly indicated that these factors have highly significant impacts on the variations of frequency shift.

Journal ArticleDOI
TL;DR: Some heuristic conclusion for determining possible bot infection in a certain host is presented and the value of the similarity coefficient for the comparisons between all datasets (bot datasets and benign dataset) is indicated.
Abstract: This research focuses on bot detection through implementation of techniques such as traffic analysis, unsupervised machine learning, and similarity analysis between benign traffic data and bot traffic data. In this study, we tested and experimented with different clustering algorithms and recorded their accuracy with our prepared datasets. Later, the best clustering algorithm was used to proceed with the next steps of the methodology such as determination of majority clusters (cluster with most flows), removal of duplicate flows, and calculation of similarity analysis. Results were recorded for the removal of duplicate flows stage, the results indicate how many flows each majority cluster contains and how many duplicate flows were removed from this majority cluster. Next, results for similarity analysis indicate the value of the similarity coefficient for the comparisons between all datasets (bot datasets and benign dataset). With these results we can present some heuristic conclusion for determining possible bot infection in a certain host.

Journal ArticleDOI
TL;DR: In this article, a human-limb driven piezoelectric energy harvester using two mass-loaded unimorph beam clamped on two flexible sidewalls is presented.
Abstract: We present a human-limb driven piezoelectric energy harvester using two mass-loaded unimorph piezoelectric beams clamped on two flexible sidewalls. Since vibration generated by human-limb motion has low-frequency and high amplitude characteristics, the energy harvester has been designed to up-convert the low-frequency human-limb vibration by mechanical impact of a spring less spherical metallic ball. However, instead of direct mechanical impact on the power generating elements (unimorph piezoelectric beams), the ball impacts on the bases (flexible sidewalls) of each beam to avoid mechanical wear of the piezo-materials. While excited by human-limb motion, the ball impacts consecutively on the flexible sidewalls which transfer impulsive forces to the loaded mass of the respective unimorph beam. The beam vibrates at its own resonant frequency and causes voltage generation by virtue of piezoelectric effect. A proof-of-concept prototype has been fabricated and tested. At optimum load condition, each unimorph piezoelectric generator generates 96 µW average power while excited at 4.96 Hz frequency and ~2g acceleration. The device with series connected generators is capable of generating maximum 175 µW average power. Improved design and further optimization would be able to increase its power generation capability (as well as power density) to be used in wearable devices applications.

Journal ArticleDOI
TL;DR: This paper presents the development of a monolithic two degrees of freedom, piezoelectric actuated microgripper for the manipulation of micro-objects and the theoretical, simulation and experimental results reveal the good performance of the microGripper.
Abstract: This paper presents the development of a monolithic two degrees of freedom (2 DOF), piezoelectric actuated microgripper for the manipulation of micro-objects. Micromanipulation and microassembly are the major subjects of interest in recent times and are becoming increasingly important in many domains. An effort is being made to develop a novel 2 DOF microgripper, each jaw being able to move independently to grasp and rotate objects of micro sizes. Microgripper is developed based on the compliant mechanism. The designed 2 DOF compliant microgripper is modeled using FEM and PRBM approach further validated experimentally. The microgripper is actuated using APA 120-S piezoelectric stack actuators. The displacement of the microgripper and the gripping force is measured by image processing technique using LabVIEW tools. The microgripper is subjected to various tests to measure the displacement amplification ratio and micromanipulation experiments. Wire of various sizes are used to test the grasping and rotating sequence of the microgripper. The theoretical, simulation and experimental results reveal the good performance of the microgripper.

Journal ArticleDOI
TL;DR: In clarification of wireless sensor network (WSN) clustering process at household and overseas, an energy efficient cluster head formation technique is set forth with the purpose of solving the problem of arbitrary cluster head election which may cause overlying coverage and uneven energy utilization in cluster communiqué.
Abstract: In clarification of wireless sensor network (WSN) clustering process at household and overseas, an energy efficient cluster head formation technique for WSN are set forth with the purpose of solving the problem of arbitrary cluster head election which may cause overlying coverage and uneven energy utilization in cluster communique. Proposed algorithm selects the cluster head in two stages. In first stage selection of cluster head is done by professed probability and in second stage selection of cluster head is done by endurance time approximation. Simulation outcomes exhibit proposed scheme steadiness network energy in two stages in contrast with existing scheme. The network lifetime is enlarged by significant amount compared existing LEACH protocol. Furthermore, endurance time of network is elongated in contrast with EBDC algorithm as well as AEOC algorithm accomplishing the helpfulness of network energy utilization which has larger network lifespan.

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TL;DR: In this article, the effects of electric fringing-fields on the structural behavior of a MEMS shallow arch were investigated using the Galerkin method to discretize the governing nonlinear equation and obtain a lumped-parameter model of the system.
Abstract: In this paper, we investigate the effects of electric fringing-fields on the structural behavior of a MEMS shallow arch. We consider the Galerkin method-based reduced-order modeling to discretize the governing nonlinear equation and obtain a lumped-parameter model of the system. We then assume two most well-known models for demonstrating the fringing-fields effects, that is the Palmer’s and the Mejis-Fokkema models. Using the discretized model, we investigate the system nonlinear behavior assuming the two electric fringing-fields models. The presented results show that for these particular cases of arch configuration, fringing-fields effects should be considered since it improves the prediction of corresponding voltages for both snap-through and pull-in structural instabilities as well as the overall static deflection of the MEMS arch. Comparisons of the acquired numerical results with some available experimental data as well as ANSYS® based finite-elements simulations confirm that neglecting the fringing-fields effects in MEMS arches can represent a significant source of error which should be avoided using much more accurate modeling techniques.

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TL;DR: In this article, a measurement method based on an image tracking approach was used to measure gripper displacement and the temperature coefficient of resistance (TCR) was determined independently and then used to calculate the heater temperature based on the measured resistance change.
Abstract: This paper presents our work on measurement and characterization of electrothermal microgrippers for micromanipulation and microassembly applications. The SU-8 based microgrippers were designed with embedded microheaters in the actuation structures of the grippers to improve thermal efficiency and to reduce the undesirable out of plane movement of the gripper tips. Electrothermal testing and characterization have been conducted to determine the displacement between the grippers’ tips under an applied voltage. A measurement method based on an image tracking approach was used to measure gripper displacement. It has been shown that a displacement of 11 and 8 µm can be obtained at the actuation voltage of 0.65 and 0.7 V for two different designs. The microheaters were also used as a sensor to find out the heater temperature. This has been done by measuring the resistance change at the applied voltage. The temperature coefficient of resistance (TCR) was determined independently and then used to calculate the heater temperature based on the measured resistance change. The values of TCR of the thin film chromium/gold microheaters were determined to be 0.00136 and 0.00149/°C at 20 °C for the two different gripper designs which are significantly less than the value of the bulk gold material which is 0.0034/°C. The results show that it is important to determine the TCR of the thin film microheaters for accurate calculation of the heater temperature at an applied actuation voltage. In addition, the resistivity of the metal layer has been calculated and it was between 6.2 and 6.8 μΩ cm. this value is much larger than 2.44 μΩ cm for the bulk gold value. For the fabricated thin gold film based microheaters, it was found the ratio of the increase in the resistivity is the same as the ratio of decrease in the TCR value.