Showing papers in "Microsystem Technologies-micro-and Nanosystems-information Storage and Processing Systems in 2019"

Enhanced sensitivity of cancer cell using one dimensional nano composite material coated photonic crystal

Abstract: We theoretically analyze the detection of a cancer cell in the one-dimensional photonic crystal by infiltrating different sample cells in the cavity layer. The defect modes appear in their transmission spectra only if the nanocomposite layers are included on either side of the cavity layer. This analysis is carried out by a dielectric constant and the transmittance peak of the cancer cell is compared with the normal cell. The transmittance peak shifts are analyzed with various filling factors for optimization purposes. Through the shifting spectrum, the sensitivity of cancer cell from the normal cell is obtained from a minimum of 42 nm/RIU to a maximum of 43 nm/RIU.

An optimal analysis of radiated nanomaterial flow with viscous dissipation and heat source

Abstract: The present work explores the analytical study of nanofluid flow above a stretching medium with the heat source and viscous dissipation. Additional radiative effects are also incorporated. The main physical problem is offered and changed into an arrangement of combined nonlinear differential equations with appropriate transformations. Optimal homotopy analysis method is used to attain the analytical solutions of the set of nonlinear differential equations. Important predictions of the flow phenomena are explored and deliberated by means of graphs and numerical tables. Moreover, the accurateness of the existing findings is verified by equating them with the previously available work.

Nodal/saddle stagnation-point boundary layer flow of CuO–Ag/water hybrid nanofluid: a novel hybridity model

Abstract: A new type of nanofluids is known as hybrid nanofluids, which is prepared by suspending two or different forms of nanoparticles and hybrid nanoparticles in the considered base fluid. Recently, researchers have indicated that hybrid nanofluids can effectively substitute the convectional coolant especially those working at very high temperatures. In this investigation, a kind of hybrid nanofluid including copper oxide (CuO 29–50 nm) and silver (Ag 2–5 nm) nanoparticles with water as base fluid is analytically modeled to develop the problem of the nodal/saddle stagnation-point boundary layer flow and heat transfer. A new straightforward mathematical model has been presented and formulated based on Tiwari–Das nanofluid scheme. Using appropriate similarity variables, the non-linear governing PDEs are transformed into non-linear dimensionless ODEs, which are solved analytically by the well-known homotopy analysis method (HAM) and numerically using the bvp4c function from MATLAB software. For the theoretical assessment of the hemodynamics and thermal impacts, graphical configurations are plotted for the different emerging parameters. These patterns provide an interesting understanding of this theoretical model to the industrial applications. Moreover, the good agreement of present achievements with previously reported results demonstrates that the developed model can be used with great confidence to study the flow and heat transfer of hybrid nanofluid in various problems. Besides, the thermal characteristics of hybrid nanofluid are found to be higher in comparison to the base fluid and fluid containing single nanoparticles, respectively.

Detection of major depressive disorder using linear and non-linear features from EEG signals

Abstract: EEG signals are non-stationary, complex and non-linear signals. During major depressive disorder (MDD) or depression, any deterioration in the brain function is reflected in the EEG signals. In this paper, linear features (band power, inter hemispheric asymmetry) and non-linear features [relative wavelet energy (RWE) and wavelet entropy (WE)] and combination of linear and non-linear features were used to classify depression patients and healthy individuals. In this analysis the data set used is publicly available data set contributed by Mumtaz et al. (Biomed Signal Process Control 31:108–115, 2017b). The dataset consisted of 34 MDD patients and 30 healthy individuals. The classifiers used were multi layered perceptron neural network (MLPNN), radial basis function network (RBFN), linear discriminant analysis (LDA) and quadratic discriminant analysis. When linear feature was used, highest classification accuracy of 91.67% was obtained by alpha power with MLPNN classifier. When non-linear feature was used, both RWE and WE provided highest classification accuracy of 90% with RBFN and LDA classifier, respectively. The highest classification of 93.33% was achieved when combining linear and non-linear feature, i.e., combination alpha power and RWE with MLPNN as well as RBFN classifier. This paper also showed that the combination of non-linear features, i.e., RWE and WE also performed the best with highest classification accuracy of 93.33%. The study compared the accuracy, sensitivity and specificity of different classifiers along with linear and non-linear features and combination of both. The results indicated that combination alpha power and RWE showed the highest classification 93.33% accuracy in all the applied classifiers.

Darcy–Forchheimer flow and heat transfer augmentation of a viscoelastic fluid over an incessant moving needle in the presence of viscous dissipation

Abstract: The main focus of the present study is to analyse the effect of viscous dissipation Darcy–Forchheimer flow and heat transfer augmentation of a viscoelastic fluid over an incessant moving needle. The governing partial differential equations of the defined problem are reduced into a set of nonlinear ordinary differential equations using adequate similarity transformations. Obtained set of similarity equations are then solved with the help of efficient numerical method fourth fifth order RKF-45 method. The effects of different flow pertinent parameters on the flow fields like velocity and temperature are shown in the form of graphs and tables. The detailed analysis of the problem is carried out based on the plotted graphs and tables.

Thermal convection of MHD Blasius and Sakiadis flow with thermal convective conditions and variable properties

Abstract: A theoretical study on the effect of magnetohydrodynamic field on the classical Blasius and Sakiadis flows of heat transfer characteristics with variable conditions and variable properties are studied in this paper. Hydromagnetic flows and heat transfer in porous media have been considered extensively in recent years due to their occurrence in several engineering processes such as compact heat exchangers, metallurgy, casting, filtration of liquid metals, cooling of nuclear reactors and fusion control. The governing partial differential equations are converted into ordinary differential equations using the suitable similarity transformations. The transformed boundary layer equations like momentum and energy equations are solved numerically by using Runge–Kutta method. The effect of governing physical parameters over the velocity and temperature distributions is demonstrated graphically. Moreover, the local friction factor coefficient and rate of heat transfer in terms of Nusselt number are computed and discussed through tables. We validated the present solutions with already existing studies under limited cases. It is found that the thermal buoyancy parameter enhances the velocity depreciates the temperature field for both the Sakiadis and Blasius flow cases. The influence of Biot number increases skin friction coefficient and local Nusselt number for both Sakiadis and Blasius flow cases.The rate of heat transfer for temperature ratio parameter is high in Blasius flow case when compared with Sakiadis flow case.

Energy dependent cluster formation in heterogeneous wireless sensor network

Abstract: The applications of Wireless Sensor Network is increasing rapidly in almost every domain. So, the limited node’s battery life in the network should be utilized efficiently. Various approaches have been proposed earlier to lessen the usage of energy in the network and to enhance the network lifespan. In this paper we are proposing an approach for efficient cluster head selection namely Energy Dependent Cluster Formation in Heterogeneous Wireless Sensor Network (EDCF) to enhance the lifespan of network. The simulation of the proposed EDCF technique is performed in MATLAB simulator and to measure its performance the comparison is performed with various existing protocols. The proposed EDCF protocol has shown the enhancement in the lifespan of the network as compared to the previous clustering approaches.

Design of flexible textile antenna using FR4, jeans cotton and teflon substrates

Abstract: In modern technology, reduction in size and complexity of the antenna are the primary objective of recent research. This reduced size antenna is the boon in medical applications. This paper proposes monopole antenna which constitutes a simple structure and light-weight with a use of textile substrate. The prototype designed in this paper will be used for Body Centric Wireless Communications operating in 2.45 GHz Industrial, Scientific and Medical band. Return loss of − 10 dB and wide bandwidth against the conventional monopole antenna is achieved in the proposed system. Besides, a satisfactory gain characteristic has been obtained using wearable textile monopole antenna when it is compared to the conventional monopole antenna.

Dynamic model of Bryophyllum pinnatum leaf fueled BPL cell: a possible alternate source of electricity at the off-grid region in Bangladesh

Abstract: Electricity is now a basic need for the people of Bangladesh. The socio-economic development is very deliberate at the off-grid regions. Providing a glance of electricity in many places is still difficult and practically inefficient. Considering these circumstances, we have to find a method to provide some sort of electricity in the off grid regions to give light at night to the school goings, tune radios and even to charge the mobile phones. Moreover, that way of providing electricity should be reasonably efficient, eco-friendly, easy to maintain or reconstruct, and should be operated by anyone. The BPL cell technique can be a solution, which is based on the voltaic cell principle, where some pairs of electrodes such as copper–zinc pair immersed in the juice of Bryophyllum pinnatum (miracle plant) leaf. Cell performance depends fundamentally on the quantity of the filtered leaf juice. Changing the juice means recharging the cell. Our new dynamic-electrolyte model came across as very efficient by providing long termed output power comparatively the previous model, static-electrolyte model. the output performance of the new model is very good and forced to look forward to constructing a nano leveled power plant practically at an affordable cost in the off-grid regions.

Underwater motion characteristics evaluation of multi amphibious spherical robots

Abstract: Information exchanges and cooperative movements of multi robots have become a hot topic in robotics. To improve the performance and working efficiency of our amphibious spherical robot, the leader–follower method, which could realize the coordinated movement and formation keeping for three or more robots, was adopted in this paper. Firstly, this paper depicts the formation design of multi robots, and the formation system is made up of two or three robots which can formed longitudinal formation, linear formation and triangular formation. And then, the formation strategy of multi robots based on leader–follower method was depicted and analyzed, including the principle of relative attitude observation and the design of kinematic controller. Finally, based on the theoretical analysis and calculation, a series of underwater experiments were carried out to test the performance of amphibious spherical multi robots with different formations; these experiments included longitudinal formation motion test, linear formation motion test, and triangular formation motion test. The experimental results demonstrated that the multi robots could realize different underwater formation motion accurately.

Design and evaluation of sensorized robot for minimally vascular interventional surgery

Abstract: Remote-controlled vascular interventional robots (RVIRs) are being developed to reduce the occupational risk of the intervening physician, such as radiation, chronic neck and back pain, and increase the accuracy and stability of surgery operation. The collision between the catheter/guidewire tip and blood vessels during the surgery practice is important for minimally invasive surgery because the success of the surgery mainly depends on the detection of collisions. In this study, we propose a novel sensing principle and fabricate a sensorized RVIR. The proposed sensorized RVIR can accurately detect force and reconstruct force feedback. The performance of the proposed sensorized RVIR is evaluated through experiments. The experiment results show that it can accurately measure static force and time-varying force. Subtle force changes caused by changes of movement direction in surgeries can also be detected. In addition, the proposed sensorized RVIR has higher operation efficiency than our previous prototype.

Flow field analysis of a passive wavy micromixer with CSAR and ESAR elements

Abstract: The performance analysis of wavy micromixers with split and recombine (SAR) elements has been carried out. The two types of SAR elements viz. circular split and recombine elements and elliptical split and recombine elements are used to get benefit of SAR mechanism. The main concept in the proposed design is to enhance the interfacial area between the two fluids by creating a transverse flow and split and recombination of fluid flow streams with the help of SAR elements. The effects of balanced split and unbalanced split of SAR elements and operational parameter Reynolds number on the mixing index and pressure drop are evaluated. The COMSOL Multiphysics 5.0 is used for computational fluid dynamics analysis of micromixers. The analysis is carried out for balanced and unbalanced split of the mixing elements at various Reynolds numbers in the range of 0.1–75. The computation interfacial patterns on the planes perpendicular to the direction of fluid flow, mixing index and pressure drop are studied in depth. The results indicate that at inlet Reynolds number below 5, the mixing performance is diffusion dominated. However at Reynolds number greater than 5, the mixing index increases intensely due secondary flow and separation vortices, as well as SAR effect.

Nonlinear free and forced vibrations of graphene nanoplatelet reinforced microbeams with geometrical imperfection

Abstract: Nonlinear free/forced vibration of a functionally graded graphene nanoplatelet (GNP) reinforced microbeam having geometrical imperfection which is rested on a non-linear elastic substrate have been studied in the present research. Graphene Platelets have been uniformly and non-uniformly scattered in the cross section area of the microbeam. Non-uniform distribution of GNPs is considered to be linear or non-linear type. Geometric imperfection is considered similar to the first vibration mode of microbeam. Size effects due to micro-rotations are captured in this study by means of modified couple stress elasticity. In the case of forced vibration, a uniform harmonic load is exerted to the top surface of microbeam. Harmonic balance method has been implemented to solve the non-linear governing equation of microbeam having quadratic and cubic nonlinearities. In this regard, frequency-amplitude curves are obtained and their trends are studied by changing of GNP amount and distribution, geometric imperfection, forced amplitude and hardening foundation.

Pull-in behavior of functionally graded micro/nano-beams for MEMS and NEMS switches

Abstract: In this paper, pull-in behavior of cantilever micro/nano-beams made of functionally graded materials (FGM) with small-scale effects under electrostatic force is investigated. Consistent couple stress theory is employed to study the influence of small-scale on pull-in behavior. According to this theory, the couple tensor is skew-symmetric by adopting the skew-symmetric part of the rotation gradients. The material properties except Poisson’s ratio obey the power law distribution in the thickness direction. The approximate analytical solutions for the pull-in voltage and pull-in displacement of the microbeams are derived using the Rayleigh–Ritz method. Comparison between the results of the present work with Osterberg and Senturia’s article for pull-in behavior of microbeams made of isotropic material reveals the accuracy of this study. Numerical results explored the effects of material length scale parameter, inhomogeneity constant, gap distance and dimensionless thickness. Presented model has the ability to turn into the classical model if the material length scale parameter is taken to be zero. A comparison between classical and consistent couple stress theories is done which reveals the application of the consistent couple stress theory. As an important result of this study can be stated that a micro/nano-beams model based on the couple stress theory behaves stiffer and has larger pull-in voltages.

CUWSN: energy efficient routing protocol selection for cluster based underwater wireless sensor network

Abstract: Energy efficient routing protocol selection for Cluster based Underwater Wireless Sensor Network (CUWSN) is aimed to support monitoring and controlling underwater scenarios in the field of Internet of Underwater Things. The crucial requirement of Underwater Wireless Sensor Network (UWSN) is to prolong network lifespan. The aim of this article is to build energy-efficient UWSN that will trim energy expenditure as well as improve performance in the underwater scenario. In the proposed CUWSN, a UWSN architecture is designed, which uses the benefits of cluster head and multi-hop transmission. The proposed CUWSN extends the network lifetime by using multi-hop transmission. The proposed CUWSN model is simulated using QualNet 7.1 simulation tool. In this article, energy consumption, throughput, packet delivery ratio, transmission delay, error signals, and packet loss parameter indicators are considered to investigate the performance of proposed CUWSN. The outcomes of proposed CUWSN exhibit that the AODV routing protocol surpasses the DYMO routing protocol by 80%, the IERP routing protocol by 75%, STAR routing protocol by 47% and ZRP routing protocol by 81% in perspective of energy efficiency. In references to other performance indicators like average path loss and average interference the IERP routing protocol and in case of throughput the ZRP routing protocol performs well among the five routing protocols. Finally, the AODV routing protocol is energy conservative in the proposed CUWSN.

Piezoelectric thermo electromechanical energy harvester for reconnaissance satellite structure

Abstract: Piezoelectric materials are widely used in aerospace industry as a source of alternate energy for micro or nanoscale electronics because of voltage dependent actuation ability. This phenomena is of absolute importance in cubic reconnaissance satellites as they have maximum number of piezoelectric patches integrated in structure. In this research work, PZT patches in the satellite structure absorbs the mechanical and thermal energy from external environment as well as from internal fluctuations and convert them into electrical energy. This electrical energy can be utilized on the spot or can be stored in batteries for wireless sensors. The experimental setup and electronic circuit is designed in order to mimic the real time conditions based on direct effect of piezoelectricity. The effect of energy generation with respect to fatigue mechanical loading condition is analyzed based on equivalent circuit method. A numerical simulation model based on commercial software ABAQUS Standard has been developed. The developed model has predicted the experimental outcome with less than $$3\%$$ error. The analytical results are in good agreement with experimental as well as with numerical calculations with less than $$5\%$$ error. The maximum output energy obtained in this study is 0.8 nJ.

Experimental investigation on size-dependent higher-mode vibration of cantilever microbeams

Abstract: A new perspective is presented to study size-dependent elasticity experimentally within micron scale utilizing dynamic approach. The size-dependent vibration of cantilever microbeams made of nickel is studied for the first three transverse modes. The normalized natural frequency of the first mode manifests strong size effect as reported. Remarkably, the normalized natural frequencies of the second and third mode also increase to 1.9 times as the thickness of microbeams decreases from 15 to 2.1 μm. Similarly the normalized bending rigidity increases to about 3.5 times. It is the first time that elastic size effect is observed in vibration of higher modes. Moreover, the size-dependent vibration of the first mode is interpreted in light of the modified couple stress theory, and the theoretical prediction also fit the experimental results of high modes very well. Hence it is confirmed that modified couple stress theory is valid for vibration of higher modes too.

Hafnium oxide based cylindrical junctionless double surrounding gate (CJLDSG) MOSFET for high speed, high frequency digital and analog applications

Abstract: In this paper Hafnium Oxide (HfO2) based cylindrical Junctionless Double Surrounding Gate (CJLDSG) MOSFET has been analyzed for various metrics of device performance. HfO2 based CJLDSG MOSFET has been compared with HfO2 based Cylindrical Junctionless Surrounding Gate (CJLSG) MOSFET and Silicon Oxide (SiO2) based CJLDSG MOSFET and CJLSG MOSFET. It has been observed that HfO2 based CJLDSG MOSFET shows improved analog performance in terms of higher drain current, higher transconductance, higher output conductance (gd), higher Transconductance Generation Factor (TGF), higher Early Voltage (VEA), Maximum Transducer Power Gain (MTPG), Current Gain and Subthreshold Slope (SS) close to 60 mV/decade. HfO2 based CJLDSG MOSFET shows lower channel resistance. The Cut Off Frequency (fT) and Frequency Transconductance Product (FTP) of HfO2 based CJLDSG MOSFET is maximum among all and it also offers highest frequency of operation. It also shows higher Ion/Ioff ratio. Thus, making HfO2 based CJLDSG MOSFET an ultimate device for high speed, high frequency digital and analog applications.

The communication and stability evaluation of amphibious spherical robots

Abstract: This paper aims to improve the collaboration ability and stability of amphibious spherical robots (ASRs). According to our previous researches, robots have no communication or control stability module. This study designed a new torque gyro control stability and an artificial electronic communication module devoted to allowing the robot to both move on land and underwater, which used a gyro sensor to design a closed-loop control module to perform terrestrial locomotion efficiently. Regarding the spherical robot mechanical structure and dynamic model, the robot communication module is designed, and the physical robot is set up to complete specific experiments. In addition, it is necessary to analyze the underwater and land motion to evaluate the performance of the robot stability motion and communication module, which includes the gait stability and velocity, and predicts the effects of the key parameters, such as electrode distance and emitter current of the amphibious spherical robot when it moves in underwater or on land. We also characterize communicate performance of the robots in still water with obstacles and natural water conditions.

Numerical approach for nanofluid transportation due to electric force in a porous enclosure

Abstract: In current attempt, nanoparticle Electrohydrodynamic transportation has been modeled numerically via control volume based finite element method. Mixture of Fe3O4 and Ethylene glycol is elected. Impact of radiation parameter $$ \text{(}Rd\text{)} $$ , voltage supplied $$ \text{(}\Delta \varphi \text{)} $$ , nanoparticle concentration, Permeability and Reynolds number have been displayed. Results display that permeability and thermal radiation can improve temperature gradient.

Design optimization of an electromagnetic actuation based valveless micropump for drug delivery application

Abstract: A valveless micropump based on an electromagnetic actuation for drug delivery application has been designed. The parametric studies are performed to examine the effects of the divergence angle, neck width, diffuser length, height and diameter of the pump chamber and diaphragm thickness on the flow rate. Furthermore, an optimal design of the micropump is identified, and the proposed micropump has been fabricated. Experiments are performed to validate simulation results in terms of flow rate versus frequency and flow rate versus back pressure. The proposed micropump is polymer based and thus suitable for low-cost and disposable applications.

Unified framework for IoT and smartphone based different smart city related applications

Abstract: By embracing the potential of IoT and smartphones, traditional cities can be transformed to smart cities. The success of such smart city mission is firmly vested in populace and thus it should have a bottom-up nature, initiated by the citizens. This paper focuses on the design and development of a unified framework, which can provide a platform to empower all the applications across different dimensions of urban life in a smart city. The aim of this framework is to connect citizens, data, knowledge and services related to IoT as well as smartphone based applications. Here, we categorize all the applications for the smart city in three representative types, viz. IoT based, IoT and smartphone based and smartphone as IoT based applications. We have also developed and tested one prototype following this architecture for each of these three representative category type, i.e, IoT based smart classroom, IoT and smartphone based air quality monitoring system and only smartphone based noise monitoring system to demonstrate the effectiveness of the proposed framework for the smart city scenario.

Design, analysis and fabrication of compact dual band uniplanar meandered ACS fed antenna for 2.5/5 GHz applications

Abstract: In this research, a compact meandered shape design of printed antenna with dual operating frequencies for 2.5/5 GHz applications is presented and experimentally investigated. The proposed multi band antenna is feed with asymmetric coplanar strip (ACS) and has a size of 10 mm × 19 mm. The L and meandered elements acts as a radiating elements that produces operating frequencies from 2.5 to 2.7 GHz and from 4.6 to 6.1 GHz with 200 and 1500 MHz impedance bandwidths respectively. Also, simulation study of feeding the proposed structure with microstrip concept is carried out and similar performance results are found in both ACS and microstrip techniques. The performance of the dual band antenna in terms of return loss, design evolution, radiation patterns and peak gain is studied.

Carbon nanotubes effects in magneto nanofluid flow over a curved stretching surface with variable viscosity

Abstract: The present study investigates the influence of temperature dependent viscosity on dynamics of pressure driven nanofluid flow over a curved surface. A uniform applied magnetic field perpendicular to the surface is taken into consideration. Governing nonlinear partial differential equations are modeled with the help of boundary layer approximation. Suitable similarity transformations are used to convert governing equations into nonlinear ordinary differential equations. These highly nonlinear ordinary differential equations are then solved with the help of a second order implicit finite difference scheme. Graphical and numerical results depict the impact of temperature sensitive viscosity and other physical parameters on flow of nanofluid. Viscosity parameter evidently resist the flow velocity and rise the temperature distribution in the nanofluid. It also increases the Skin friction near the boundary of the fluid.

Application of stochastic fractal search in approximation and control of LTI systems

Abstract: The present work deals with the application of evolutionary computation in approximation and control of linear time invariant (LTI) systems. Stochastic fractal search algorithm (SFS) has been proposed to obtain low order system (LOS) from LTI higher order system (HOS) as well as in speed control of DC motor with PID controller. SFS is quite simple to use in control system and employs the diffusion property present in random fractals to discover the search space. In approximation of LTI systems, the integral square error (ISE) while in control of DC motor, the integral of time multiplied absolute error has been taken as an objective/fitness functions. In system’s approximation, the results show that the proposed SFS based LOS preserves both the transient and steady state properties of original HOS. The simulation results have also been compared in terms of; ISE, integral absolute error and impulse response energy with well known familiar and recently published works in the literature which shows the superiority of SFS algorithm. In control of DC motor, the obtained results are satisfactory having no overshoot and less rise and settling times in comparison to existing techniques.

Sensitivity enhancement and temperature compatibility of graphene piezoresistive MEMS pressure sensor

Abstract: MEMS pressure sensor has shown a remarkable change in revenue collection during the year 2018. Due to recent growth in smart microsystem technology for automation systems, demand has grown substantially for sensors. High sensitivity, flexibility, miniaturization and bulk production are some of the key factors of a pressure sensor in achieving new heights in the MEMS market. In this paper, Graphene piezo resistive material has been analysed for pressure sensing elements and compared with Polysilicon in terms of sensitivity and sensor performance degradation at different temperature. MEMS pressure sensors using Polysilicon and Graphene piezo resistive materials were simulated on silicon (100) substrate by COMSOL Multiphysics 5.3a version. The simulation result shows that at room temperature polysilicon pressure sensor performs well with pressure sensitivity of 3.81 mV/psi as well as it is found that graphene pressure sensor also shows better results at room temperature showing a pressure sensitivity of 3.98 mV/psi. As on frequently increasing the temperature it is noticed that polysilicon pressure sensitivity degrades with a factor of 0.64 mV/psi. However, graphene pressure sensor shows very less variation in sensitivity at higher temperature. Although it shows a small increment of 0.02 mV/psi in the pressure sensitivity. This analysis opens the path to utilise the graphene pressure sensor at high temperature.

Simulation and comparative study on analog/RF and linearity performance of III–V semiconductor-based staggered heterojunction and InAs nanowire(nw) Tunnel FET

Abstract: This paper presents the comparative study on linearity and analog/radio frequency presentation of an III–V staggered hetero-junction nanowire (NW) TFET with Si and InAs based NW TFET of same dimension. The device parameter of analog/RF performance for low power application such as transconductance (gm), output resistance (RO), intrinsic gain (gmR0), cut-off frequency (fT), maximum frequency of oscillation (fmax), gain bandwidth product (GBW), VIP2, VIP3 as well as 1-dB compression point has been explored. There is a better improvement in analog/radio frequency presentation obtained from heterojunction NW TFET over Si and InAs TFET. The result reveals that heterojunction TFET provides superior intrinsic gain, higher cutoff frequency, higher GBW better linearity performance as compared to Si and InAs TFET.

Integral sliding mode control for nonlinear damped model of arch microbeams

Abstract: In this paper, a second order integral sliding mode controller (SMC) and a two-dimensional integral sliding mode controller are designed for a nonlinear damped model of arch microbeam with two electrodes as a bistable system. The latest model of the arch microbeam is introduced in which the squeezed film damping effect is modeled through considering nonlinear terms. The actuating voltage is considered as the control effort of the system somehow expands as a combined static DC and harmonic AC voltage. The second order integral SMC and two-dimensional integral SMC are proposed as the robust controllers to stabilize the system in the presence of the uncertain parameter due to the damping coefficient. The controller formula, stability and convergence of the closed-loop system are derived and formulated for the arch microbeam. Simulation results and comparison of the proposed controllers are presented to demonstrate the performance of the designed control schemes for achieving set point tracking in the closed-loop system.

Vibration analysis of rotating rods based on the nonlocal elasticity theory and coupled displacement field

Abstract: Free longitudinal vibration analysis of a rotating rod based on the Eringen’s nonlocal elasticity is studied in this paper. Rod is supposed to rotate around a fixed axis with a constant angular velocity. To capture the effect of the rotational motion into analysis of the continuous system, a linear proportional relation is introduced between axial and angular velocities. For the first time the mentioned relation is presented based on the internal motions of the infinitesimal element. This novelty makes the rotational displacement as a dependent function of axial displacement playing a significant role through the analysis. Variational approach is adopted to derive the equations of motion for clamped–clamped and clamped-free boundary conditions. For verification of the results obtained from the Galerkin approach, comparison with technical literature is reported. Finally current results illustrate the dependency of the dynamic-vibration analysis of the presented system on the nonlocality and the rotational velocity parameter. This dependency shows the decrement of the frequency with increment in both the angular velocity and the nonlocal parameter. As a result, the mentioned parameters are key factors in the design and analysis of such systems.

Extended finite element method (XFEM) analysis of fiber reinforced composites for prediction of micro-crack propagation and delaminations in progressive damage: a review

Abstract: Various methodologies and frameworks have been developed for extended finite element method (XFEM) to simulate two-dimensional and three-dimensional microcrack initiation and propagation through versatile material models for structures. In addition, mixed-mode cohesive zone is investigated and estimated for delamination, matrix cracking and fiber breakage in composite laminate models. The validation of Multiscale modeling for the fiber uniformity during the tensile behavior, prediction of crack and properties of composite material analyzed by XFEM modeling for the damage modes and comparison with the experimental work and the author’s recent experimental case study is presented. The further development is application of extended cohesive damage modelling (ECDM) without the additional complications of degrees of freedom and effective simulation of multicrack propagation and damage model. The capabilities of ECDM to work for single mode delamination and mixed mode delamination with a better efficiency and accuracy are well explained. The study simplifies the application of extended FEM for the prediction of multiple cracks applied to carbon fiber reinforced composites (CFRCs), hence provides a better understanding for extended cohesive damage modelling for the recent developments.