Influence of imperfectly bonded piezoelectric layer with irregularity on propagation of Love-type wave in a reinforced composite structure

Abhishek Kumar Singh,Mriganka Shekhar Chaki,Bristi Hazra,Shruti Mahto 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.62 No.3

The present paper investigates the propagation of Love-type wave in a composite structure comprised of imperfectly bonded piezoelectric layer with lower fiber-reinforced half-space with rectangular shaped irregularity at the common interface. Closed-form expression of phase velocity of Love-type wave propagating in the composite structure has been deduced analytically for electrically open and short conditions. Some special cases of the problem have also been studied. It has been found that the obtained results are in well-agreement to the Classical Love wave equation. Significant effects of various parameters viz. irregularity parameter, flexibility imperfectness parameter and viscoelastic imperfectness parameter associated with complex common interface, dielectric constant and piezoelectric coefficient on phase velocity of Love-type wave has been reported. Numerical computations and graphical illustrations have been carried out to demonstrate the deduced results for various cases. Moreover, comparative study has been performed to unravel the effects of the presence of reinforcement and piezoelectricity in the composite structure and also to analyze the existence of irregularity and imperfectness at the common interface of composite structure in context of the present problem which serves as a salient feature of the present study.

Influence of surface irregularity on dynamic response induced due to a moving load on functionally graded piezoelectric material substrate

Abhishek K. Singh,Anil Negi,Siddhartha Koley 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.23 No.1

The present study investigate the compressive stress, shear stress, tensile stress, vertical electrical displacement and horizontal electrical displacement induced due to a load moving with uniform velocity on the free rough surface of an irregular transversely isotropic functionally graded piezoelectric material (FGPM) substrate. The closed form expressions of said induced stresses and electrical displacements for both electrically open condition and electrically short condition have been deduced. The influence of various affecting parameters viz. maximum depth of irregularity, irregularity factor, parameter of functionally gradedness, frictional coefficient of the rough upper surface, piezoelectricity/dielectricity on said induced stresses and electrical displacements have been examined through numerical computation and graphical illustration for both electrically open and short conditions. The comparative analysis on the influence of electrically open and short conditions as well as presence and absence of piezoelectricity on the induced stresses and induced electrical displacements due to a moving load serve as the salient features of the present study. Moreover, some important peculiarities have also been traced out by means of graphs.

Noninvasive versus invasive ventilation: one modality cannot fit all during COVID-19 outbreak

Singh Abhishek 대한마취통증의학회 2020 Korean Journal of Anesthesiology Vol.73 No.4

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Curvature Properties of 𝜂-Ricci Solitons on Para-Kenmotsu Manifolds

Singh, Abhishek,Kishor, Shyam Department of Mathematics 2019 Kyungpook mathematical journal Vol.59 No.1

In the present paper, we study curvature properties of ${\eta}$-Ricci solitons on para-Kenmotsu manifolds. We obtain some results of ${\eta}$-Ricci solitons on para-Kenmotsu manifolds satisfying $R({\xi},X).C=0$, $R({\xi},X).{\tilde{M}}=0$, $R({\xi},X).P=0$, $R({\xi},X).{\tilde{C}}=0$ and $R({\xi},X).H=0$, where $C,\;{\tilde{M}},\;P,\;{\tilde{C}}$ and H are a quasi-conformal curvature tensor, a M-projective curvature tensor, a pseudo-projective curvature tensor, and a concircular curvature tensor and conharmonic curvature tensor, respectively.

Influence of loose bonding, initial stress and reinforcement on Love-type wave propagating in a functionally graded piezoelectric composite structure

Abhishek K. Singh,Zeenat Parween,Mriganka S. Chaki,Shruti Mahto 국제구조공학회 2018 Smart Structures and Systems, An International Jou Vol.22 No.3

This present study investigates Love-type wave propagation in composite structure consists of a loosely bonded functionally graded piezoelectric material (FGPM) stratum lying over a functionally graded initially-stressed fibre-reinforced material (FGIFM) substrate. The closed-form expressions of the dispersion relation have been obtained analytically for both the cases of electrically open and electrically short conditions. Some special cases of the problem have also been studied and the obtained results are found in well-agreement with the classical Love wave equation. The emphatic influence of wave number, bonding parameter associated with bonding of stratum with substrate of the composite structure, piezoelectric coefficient as well as dielectric constant of the piezoelectric stratum, horizontal initial stresses, and functional gradedness of the composite structure on the phase velocity of Love-type wave has been reported and illustrated through numerical computation along with graphical demonstration in both the cases of electrically open and electrically short condition for the reinforced and reinforced-free composite structure. Comparative study has been carried out to analyze the distinct cases associated with functional gradedness of the composite structure and also various cases which reveals the influence of piezoelectricity, reinforcement and horizontal initial stress acting in the composite structure, and bonding of the stratum and substrate of the composite structure in context of the present problem which serves as one of the major highlights of the study.

Immobilization of Candida antarctica lipase onto cellulose acetate-coated Fe2O3 nanoparticles for glycerolysis of olive oil

Abhishek Kumar Singh,Mausumi Mukhopadhyay 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.7

Candida antarctica lipase was covalently immobilized onto the surface of cellulose acetate-coated Fe2O3nanoparticles. The characterizations of immobilized lipase were examined by Fourier transform infrared spectrophotometer(FTIR) and field emission gun-scanning electron microscopy (FEG-SEM). The immobilized lipase was assayedfor production of monoglycerides (MG) and diglycerides (DG) by glycerolysis of olive oil in a solvent medium. Theeffect of various reaction conditions on the MG and DG production such as reaction time, temperature, the molar ratioof glycerol to oil and amount of immobilized lipase was investigated. The optimum condition for MG and DG productionwas found at 50 oC temperature and 0.025 g of lipase with the molar ratio of glycerol to oil 1.5 : 1 in 5 h of reactiontime. The effect of substrate concentration on enzymatic activity of the free and immobilized lipase showed the bestfits to the Lineweaver-Burk plots. The Km and Vmax values of immobilized lipase were found to be 25mM and 0.58mM/min, whereas that for free lipase was 52.63mM and 1.75mM/min, respectively. The activation and deactivation energywas found to decrease for immobilization of lipase on cellulose acetate-coated Fe2O3 nanoparticles.

Influence of loose bonding, initial stress and reinforcement on Love-type wave propagating in a functionally graded piezoelectric composite structure

Singh, Abhishek K.,Parween, Zeenat,Chaki, Mriganka S.,Mahto, Shruti Techno-Press 2018 Smart Structures and Systems, An International Jou Vol.22 No.3

This present study investigates Love-type wave propagation in composite structure consists of a loosely bonded functionally graded piezoelectric material (FGPM) stratum lying over a functionally graded initially-stressed fibre-reinforced material (FGIFM) substrate. The closed-form expressions of the dispersion relation have been obtained analytically for both the cases of electrically open and electrically short conditions. Some special cases of the problem have also been studied and the obtained results are found in well-agreement with the classical Love wave equation. The emphatic influence of wave number, bonding parameter associated with bonding of stratum with substrate of the composite structure, piezoelectric coefficient as well as dielectric constant of the piezoelectric stratum, horizontal initial stresses, and functional gradedness of the composite structure on the phase velocity of Love-type wave has been reported and illustrated through numerical computation along with graphical demonstration in both the cases of electrically open and electrically short condition for the reinforced and reinforced-free composite structure. Comparative study has been carried out to analyze the distinct cases associated with functional gradedness of the composite structure and also various cases which reveals the influence of piezoelectricity, reinforcement and horizontal initial stress acting in the composite structure, and bonding of the stratum and substrate of the composite structure in context of the present problem which serves as one of the major highlights of the study.

Secure Linear Feedback Shift Register based IPv6 in VANET

Abhishek singh,Shekhar Verma,Geetam Singh Tomar 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.2

In this paper, Linear Feedback Shift Register (LFSR) based IPv6 address generation has been proposed for low IP acquisition time during handoff in Vehicular Adhoc Networks (VANET). The mechanism reduces handoff latency and packet loss rate by removing link layer address conflict and duplicate address detection (DAD). VANETs are characteristics by frequent handoffs that need regular address reconfiguration which increases the handoff latency. The latency increases further due to the need for DAD to prevent link layer address conflict. LFSR based IPv6 in VANET decreases the address reconfiguration time and handoff latency by providing a unique seed value in Router Advertisement (RA) which is generated through modified LFSR algorithm and is combined with vehicle’s MAC ID to give a unique host ID. Since the mechanism is able to generate different unique host ID for same MAC ID, it eliminates the need of DAD by minimizing the probability of link layer address conflict to a negligible value. This also increases the IP configuration scalability. The algorithm only modifies the control signal RA and does not require any change in the VANET architecture. Simulation results confirm that this mechanism performs better than Mobile IPv6 (MIPv6) and can be incorporated as a standard IP acquisition technique for high mobility networks like VANET.

Pole Placement Using Genetic Algorithm with Integral Control

Abhishek Pratap Singh,Ashish Patra 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.6

This paper presents the application of genetic algorithms to find the optimum feedback gains in pole placement with integral control to get the desired performance in control system. Performances are measured in terms of key parameters like settling time, peak overshoot, undershoot, rise time etc in control system. The major drawbacks of pole placement technique are to get optimum location of poles and we cannot place zeros at desired locations. Dominating concept of poles is enough for placing poles for systems which transfer functions are without zeros. But if there are zeros in transfer function then it is not enough to place pole with dominating pole concept because presence of zero can destroy the dynamic response of control system. In this paper genetic algorithm is used to find the optimum locations of poles to get the desired response and compensate the effect of zeros on transient in case zeros are present in transfer function. GA is a population based algorithm to find the global solution of a problem. This paper compares the unit step response of a plant with presence of zero in transfer function. The same GA based technique is used for finding optimum location of poles to get the desired response for magnetic levitation system. This analysis is well supported by the simulation and experimental results done using MATLAB and Simulink.

Empirical equation and experimental validation of shear parameters for high strength concrete (HSC)

Brijesh Singh,Ojha P N,Patel Vikas,Trivedi Amit,Singh Abhishek 아시아콘크리트학회 2021 Journal of Asian Concrete Federation Vol.7 No.2

With many benefits of the high strength concrete (HSC) the more brittle behaviour that leads to sudden failure makes it important for proper understanding of its behaviour and safe and efficient estimation of capacities. Research on the behaviour of HSC has been extensively carried out since last decade. HSC has higher tensile strength hence a higher cracking shear can be expected. This paper analyzes the different international standards available for estimating concrete’s component of shear strength for reinforced cement concrete (RCC) beam. Different important factors mainly strength in compression, steel reinforcement (dowel action), ratio of shear span and depth, size effect i.e. depth along with the aggregate type (density of concrete) contributing to shear stress (Tc) of concrete has been also analyzed and thereafter, an equation has been proposed to compute or predict Tc value for concrete of both normal and higher grade or strength. The proposed equation has been validated by experimental results wherein 12 RCC beams (with and without reinforcement for shear) were cast and tested to fail in shear. The experimental results validated the proposed equation with considerable factor of safety keeping in view the sudden and brittle nature of failure in concrete in case of shear.