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1

Sustainable deployment of crushed concrete aggregates strengthened with cement and sand

Sharma V., Kumar A., Kaur A.

Archives of Materials Science and Engineering

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2022

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Vol. 113, nr 1

19--34

EN

Purpose: Paper assessed the feasibility of crushed concrete aggregates (CCA), a subsidiary of construction and demolition (C&D) waste, blended with cement and sand to form a composite for civil engineering field applications. Design/methodology/approach: The compaction and strength characteristics of CCA were observed by conducting Proctor compaction and California Bearing Ratio (CBR) tests. Different proportions of CCA, sand and cement were used. Moreover, the effect of curing period (0, 4, 7, 14 and 28 days) was also studied. In addition, regression analyses were performed to develop empirical expressions to predict the compaction and strength characteristics of the CCA composite. Findings: Increasing the CCA content up to 50% increases the maximum dry unit weight (MDUW) and decreases the optimum moisture content (OMC). However, on further increasing its content the MDUW decreases and OMC increases. Percent increase in the CBR value can go up to 412% if the CCA content is increased up to 50%. However, the percent reduction in CBR of about 20% can take place if 100% CCA content is used. Moreover, multiple regression shows that the experimental results are in good agreement with the predicted values. Research limitations/implications: The results obtained are purely dependent on the type of material. However, they are in favour of the used material as a probable option for road sub-base layer, and also for reducing burden on available natural resources. Therefore, it is recommended to conduct some initial tests to confirm the feasibility of the material. Practical implications: The proposed study will guide the design Engineers to choose CCA as one of the potential materials for road construction. Originality/value: It was observed that there is a need to maximize the utilization of C&D waste without making any compromise with its mechanical properties. So keeping that in view, the present study was conducted.

2

Dispersion of Rayleigh Waves in a Microstructural Couple Stress Substrate Loaded with Liquid Layer Under the Effects of Gravity

Sharma V., Kumar S.

Archives of Acoustics

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2018

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Vol. 43, No. 1

11--20

EN

Bone loss is one of the serious health issues in bedridden patients or young generation due to lack of physical activities. Mechanical forces are exerted on the bones through ground reaction forces, liquid loadings and by other contraction activities of the muscles. We are assuming an isotropic half-space with mechanical properties equivalent to that of bone exhibiting microstructures. Consistent couple stress theory introduces an additional material parameter called characteristic length which accounts for inner microstructure of the material. Dispersion relations for leaky Rayleigh waves are derived by considering a model consisting of couple stress half space under the effects of gravity and loaded with inviscid liquid layer of finite thickness or a liquid half space. Impact of the gravity, liquid loadings and microstructures of the material are investigated on propagation of leaky Rayleigh type waves. Phase velocity of leaky Rayleigh waves is studied for five different values of characteristic length parameter which are of the order of internal cell size of the considered material. Variations in phase velocity of leaky Rayleigh waves are also studied under the effect of gravity parameter and thickness of liquid loadings.

3

Dispersion of SH waves in a viscoelastic layer imperfectly bonded with a couple stress substrate

Sharma V., Kumar S.

Journal of Theoretical and Applied Mechanics

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2017

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Vol. 55 nr 2

535--546

EN

The paper deals with propagation of SH waves in a viscoelastic layer over a couple stress substrate with imperfect bonding at the interface. A dispersion equation of SH waves in a viscoelastic layer overlying the couple stress substrate with an imperfect interface between them has been obtained. Dispersion equations for propagation of SH waves with perfectly bonded interface and slippage interface between two media are also obtained as particular cases. Effects of the degree of imperfectness of the interface are studied on the phase velocity of SH waves. The dispersion curves are plotted and the effects of material properties of both couple stress substrate and viscoelastic layer are studied. The effects of internal microstructures of the couple stress substrate in terms of characteristic length of the material are presented. The effects of heterogeneity, friction parameter and thickness of the viscoelastic layer are also studied on the propagation of SH waves.

4

Thermal instability of a Rivlin-Ericksen nanofluid saturated by a Darcy-Brinkman porous medium: a more realistic model

Rana G. C., Chand R., Sharma V.

Engineering Transactions

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2016

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Vol. 64, iss. 3

271--286

EN

In this paper, we study thermal instability in a horizontal layer of Rivlin-Ericksen elasticoviscous nanofluid in porous medium. Brinkman model is used as a porous medium and RivlinEricksen fluid model is used to describe the rheological behavior of nanofluid. In the earlier model (Chand and Rana [18]), we constrained both temperature and nanoparticle volume fractions at the boundaries of Rivlin-Ericksen nanofluid layer. In this paper, we assume that the value of temperature can be constrained on the boundaries, while the nanoparticle flux is zero on the boundaries. The considered boundary condition neutralizes the possibility of oscillatory convection due to the absence of two opposing forces, and only stationary convection occurs, in which Rivlin-Ericksen elastico-viscous nanofluid behaves like an ordinary nanofluid. The effects of Lewis number, medium porosity, modified diffusivity ratio, Darcy-Brinkman number and concentration Rayleigh number in stationary convection are discussed analytically and numerically. The results of this study are in good agreement with the results published earlier.

5

The effect of rotation on the onset of electrohydrodynamic instability of an elastico-viscous dielectric fluid layer

Rana G. C., Chand R., Sharma V.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2016

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Vol. 64, nr 1

143--149

EN

In this paper the combined effect of uniform rotation and AC electric field on the onset of instability in a horizontal layer of an elastico-viscous fluid stimulated by the dielectrophoretic force due to the variation of dielectric constant with temperature is studied. Walters’ (model B’) fluid model is used to describe rheological behaviour of an elastico-viscous fluid. The onset criterions for stationary and oscillatory convection are derived for the case of free-free boundaries. It is observed that Walters’ (model B’) fluid behaves like an ordinary Newtonian fluid and rotation has stabilizing influence whereas AC electric field has destabilizing influence on the stability of the system. The necessary condition for the occurrence of oscillatory convection is also obtained. The present results are in good agreement with the earlier published results.

6

Effects of liquid loadings on lamb waves in context of size dependent couple stress theory

Sharma V., Kumar S.

Journal of Theoretical and Applied Mechanics

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2015

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Vol. 53 nr 4

925—934

EN

For understanding the effects of an internal microstructure, generalised microcontinuum theories with additional microstructural parameters are developed. One such a parameter, called the characteristic length of the material comparable with the internal cell size of the material is involved in the couple stress theory. The problem of propagation of Lamb waves in a plate with an internal microstructure and loaded with an inviscid liquid on both sides is studied using the couple stress theory. The dispersion equation of Lamb waves with the liquid loadings is derived. The impact of the liquid loadings is studied on the propagation of Lamb waves. The effect of the characteristic length is also studied on the phase velocity of Lamb waves in the plate for various modes in the presence of liquid loadings.

7

Stability of incompressible Rivlin-Ericksen elastico-viscous superposed fluid in porous medium

Rana G. C., Sharma V., Kango S. K.

International Journal of Applied Mechanics and Engineering

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2012

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Vol. 17, no. 2

471-480

EN

The stability of a Rivlin-Ericksen elastico-viscous superposed fluid in a porous medium is considered. The system is found to be stable/unstable for bottom heavy / top heavy configurations density wise as in a Newtonian viscous fluid. For an exponential varying density, viscosity, viscoelasticity, medium porosity and medium permeability, the system is found to be stable for all wave numbers for becomes stable stratifications and unstable for the unstable stratifications. The behavior of growth with respect to fluid kinematic viscosity, viscoelasticity, medium porosity and medium permeability is examined analytically and graphically.

8

Development and validation of a TLC-densitometric method for the simultaneous quantitation of icariin and L-arginine from commercial formulations

Gupta P. K, Kuber V. V, Ghosh V. K, Bhope S. G, Sharma V., Purohit S

Acta Chromatographica

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2011

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Vol. 23, no. 3

447--458

EN

A simple, rapid, and specific thin layer chromatographic (TLC) method has been developed and validated for the simultaneous estimation of icariin and L-arginine from commercial polyherbal formulations for sexual dysfunction. The separation of the methanol extract of these formulations was achieved on silica gel 60 F254 aluminum backed TLC plates by using ethyl acetate-acetone-glacial acetic acid-formic acid-water 12:2:1:2:2 (υ/υ) as mobile phase. Densitometric analysis of icariin and L-arginine was monitored in absorbance mode at 270 and 195 nm, respectively. The linear regression analysis data for the calibration plots for icariin and L-arginine showed good linear relationship with r2 = 0.9984 +- 0.01 and 0.9968 +- 0.02, in the concentration ranges of 250–750 and 500–1500 ng/spot, respectively. The method was validated for precision, robustness, and recovery. The average percentage recovery was found to be 98.26% for icariin and 99.63% for L-arginine. The limits of detection and quantitation were 72, 116 and 238, 383 ng/spot, respectively, for icariin and L-arginine. Statistical analysis proves that the method is repeatable and selective for the estimation of the targeted drugs. Since the proposed mobile phase effectively resolves the icariin and L-arginine, this method can be applied for the identification and quantitation of these components in herbal extracts and marketed formulations.

9

Stability of stratified elasto-viscous Walters' (Model B') fluid in the presence of horizontal magnetic field and rotation

Sharma V., Gupta U.

Studia Geotechnica et Mechanica

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2010

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Vol. 32, nr 2

41-53

EN

The effect of horizontal magnetic field is considered on the stability of stratified viscoelastic Walters' (Model B') fluid in the presence of rotation. In contrast to the Newtonian fluids, the system is found to be unstable for small wavelength perturbations for the case of stable stratification. It is also found that the magnetic field stabilizes the certain wave-number band for unstable stratification in the presence of rotation and this wave - number range increases with the increase in magnetic field and decreases with the increase in kinematic visco-elasticity.

10

Thermal convection of micropolar fluid in the presence of suspended particles in rotation

Sharma V., Gupta S.

Archives of Mechanics

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2008

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Vol. 60, nr 5

403-419

EN

A study has been made of the convection of micropolar fluids heated from below in the presence of suspended particles (fine dust) and uniform vertical rotation Omega (0; 0; Omega). The effect of Coriolis forces on the stability is chosen along the direction of the gravitational field. It is found that the presence of coupling between thermal and micropolar effects, rotation parameter and suspended particles may introduce overstability in the system. Using the Boussinesq approximation, the linearized stability theory and normal mode analysis, the exact solutions are obtained for the case of two free boundaries. Graphs have been plotted by giving numerical values to the parameters accounting for rotation Omega (0; 0; Omega) and the dynamic microrotation viscosity kappa and coefficient of angular viscosity gamma' to depict the stability characteristics, for both the cases of stationary convection and overstability. It is found that Rayleigh number for the case of overstability and stationary convection increases with increase in rotation parameters and decreases with increase in micropolar coefficients, for a fixed wave number, showing thereby the stabilizing effect of rotation parameters and destabilizing effect of micropolar coefficients on the thermal convection of micropolar fluids. Thus there is a competition between the stabilizing effect of rotation parameters and destabilizing effect of micropolar coeffcients and the suspended particles. It is also found from the graphs that the Rayleigh number for the case of overstability is always smaller than the Rayleigh number for the case of stationary convection, for a fixed wave number.

11

Novel Coordination Complexes of the Trivalent Ruthenium, Rhodium and Iridium with Hydrazones Derived from Isatin Hydrazide and Various Aldehydes with Spectral and Biological Characterization

Sharma V., Srivastava S., Srivastava A.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 3

387-396

EN

Aseries of several new ruthenium(III), rhodium(III) and iridium(III) complexes with hydrazones of general formula [M(LH)3]Cl3 were synthesized in order to meet requirements essential for biological properties. Hydrazones were formed by isatin hydrazide and various aldehydes namely anisaldehyde, benzaldehyde, o-chlorobenzaldehyde, p-chlorobenzaldehyde and p-fluorobenzaldehyde. Physicochemical characterization of compounds has been carried out by elemental analyses, spectroscopic (IR, electronic, 1H NMR), thermogravimetric and magnetic studies. These complexes show higher conductance values, supporting their electrolytic nature. All the studies revealed octahedral nature of the complexes with nitrogen and oxygen of azomethine and carbonyl group as binding sites and exhibited monomeric nature of the complexes. Rhodium(III) and iridium( III) complexes were found diamagnetic and show intense absorptions while ruthenium( III) complexes show paramagnetic behaviour. In addition, antifungal and antibacterial studies have been carried out in vitro for investigated compounds against fungus A. niger and F. oxysporium and bacteria E. coli and S. aureus. Most of the metal chelates show higher biocidal activity for the above microorganisms than that of the free ligand.

12

Stability of stratified elastico-viscous Walters' (Model B') fluid in the presence of horizontal magnetic field and rotation in porous medium

Sharma V., Sunil, Gupta U.

Archives of Mechanics

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2006

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Vol. 58, nr 2

187-197

EN

Combined effect of magnetic field and rotation is considered on the stability of stratified visco-elastic Walters' (Model B') fluid in porous medium. In contrast to the Newtonian fluids, the system is found to be unstable at stable stratification for low values of permeability or high values of kinematic viscoelasticity. Magnetic field is found to stabilize the small wavelength perturbations for unstable stratification. Variation of growth rate in the case of unstable stratification is depicted graphically with the variation in viscosity, viscoelasticity and permeability. It has been found that the growth rate increases with the increase in kinematic viscosity and permeability, whereas it decreases with the increase in kinematic viscoelasticity.

13

Stability of stratified Walters' (Model B') viscoelastic fluid in stratified porous medium

Sunil D., Sharma R., Sharma V.

Studia Geotechnica et Mechanica

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2004

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Vol. 26, nr 1-2

35-52

PL

Przedstawiono liniową stabilność uwarstwionej cieczy Waltersa (model B') w uwarstwionym ośrodku porowatym. Rozważono przypadki zmian wykładniczych gęstości, lepkości, lepkosprężystości, porowatości i przepuszczalności środowiska. Stwierdzono, że w przypadku potencjalnie stabilnego uwarstwienia układ jest stabilny lub niestabilny w zależności od kinematycznej lepkosprężystości, która może osiągać wartość mniejszą lub większą od wartości otrzymanej przez podzielenie przepuszczalności środowiska przez jego porowatość. Stanowi to przeciwieństwo stabilności uwarstwionej cieczy Newtona. Jednakże układ jest niestabilny w przypadku zakłóceń wszystkich liczb falowych dla potencjalnie niestabilnego uwarstwienia. Jeżeli wprowadzi się pewne ograniczenia, to szybkość wzrostu zwiększa się lub zmniejsza wraz ze zwiększającymi się wartościami parametrów uwarstwienia. Oddzielnie omówiono wpływ zmiennego poziomego pola magnetycznego i jednorodnej rotacji. Szybkość wzrostu stabilności w zależności od prędkości Alfvena (w przypadku pola magnetycznego) oraz w zależności od prędkości kątowej (w przypadku rotacji) zbadano analitycznie i stwierdzono, że w pewnych warunkach zarówno pole magnetyczne, jak i rotacja mają sprzężony wpływ na stabilność.

EN

The linear stability of stratified Walters' (model B') fluid in stratified porous medium is presented. The case of exponentially varying density, viscosity, viscoelasticity, medium porosity and medium permeability is considered. It is found that for the potentially stable stratifications the system is stable or unstable, depending on the kinematic viscoelasticity which can be smaller or greater than the medium permeability divided by medium porosity. This is in contrast to the stability of stratified Newtonian fluid. However, the system is found to be unstable for disturbances of all wave numbers for potentially unstable stratifications. If some restrictions are imposed, then the growth rates are found to increase or decrease with increasing values of stratification parameters. The effects of variable horizontal magnetic field and uniform vertical rotation have also been discussed separately. The behaviour of growth rate with respect to the Alfven velocity (in the case of magnetic field) and angular velocity (in the case of rotation) are examined analytically and it is found that under certain conditions both magnetic field and rotation have a dual effect on this stability problem.

14

The instability of streaming Rivlin-Ericksen fluids in porous medium

Sharma V., Kishor K., Rana G.

Studia Geotechnica et Mechanica

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2001

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Vol. 23, nr 3-4

83--93

PL

Badano niestabilność przepływu cieczy Rivlina-Ericksena w ośrodku porowatym. Przyjęto, że ich konfiguracja jest denna. Stwierdzono, że jeśli nie było napięcia powierzchniowego, to przepływ nie wpływał na zaburzenia poprzeczne do jego kierunku pod warunkiem, że zaniedbano zaburzenia w kierunku przepływu, podczas gdy w przypadku zaburzeń we wszystkich innych kierunkach stwierdzono niestabilność dla pewnego zakresu liczby falowej. Napięcie powierzchniowe może tłumić tę niestabilność Kelvina-Helmholtza w przypadku niewielkich zaburzeń długości fali, a porowatość i lepko-sprężystość ośrodka zmniejsza zakres stabilności w odniesieniu do różnicy w szybkościach przepływu. Napięcie powierzchniowe stabilizuje pewien zakres liczby falowej dla powierzchniowej konfiguracji.

EN

The instability of streaming Rivlin-Ericksen fluids in porous medium is considered. The configuration is taken to be bottom-heavy. In the absence of surface tension, the perturbations transverse to the direction of streaming are found to be unaffected by the presence of streaming if perturbations in the direction of streaming are ignored, whereas for perturbations in all other directions, there exists the instability for a certain wave number range. The surface tension is able to suppress this Kelvin-Helmoltz instability for smali wave length perturbations, and the medium porosity and the viscoelasticity reduce the stability rangę given in terms of a difference in streaming velocities. For the top heavy configurations, the surface tension stabilizes a certain wave number range.

15

Thermosolutal instability of Walters' (model B') visco-elastic rotating fluid permeated with suspended particles and variable gravity field in porous medium

Sharma V., Rana G. C.

International Journal of Applied Mechanics and Engineering

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2001

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Vol. 6, no 4

843-860

EN

The thermosolutal instability of Walters' (model B') elastico-viscous rotating fluid in a porous medium is considered in the presence of a uniform rotation, suspended particles and variable gravity field. the stable solute gradient, rotation, gravity field, suspended particles and viscoelasticity introduce oscillatory modes. For the stationary convection, the stable gradient and rotation have stabilizing effects and suspended particles are found to have destabilizing effect on the system, whereas the medium permeability has destabilizing or stabilizing efect on the system under certain conditions. The effects of stable solute gradient, rotation, suspended particles, medium permeability have also been shown graphically.

16

Thermosolutal instability of Walters' (model b') rotating fluid with vertical magnetic and varying gravity field in a porous medium

Sharma V., Sharma S.

International Journal of Applied Mechanics and Engineering

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2001

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Vol. 6, no 3

591-611

EN

The thermosolutal instability of Walters' (model B') elastico-viscous rotating fluid in a porous medium is considered in the presence of a uniform magnetic field and varying gravity field. For the case of stationary convection, the solute parameter delays the onset of convection. The system is stable or unstable as gravity increases or decreases in the presence of rotation and magnetic field stabilizes the system for TA1 < [(1+x0)+PQ1]2 [(1+x0)P2] as gravity increases or decreases. The porous medium permeability is also found to stabilize the system under certain conditions in the presence of rotation and magnetic field; whereas the kinematic viscoelasticity has no effect on the onset of convection. The magnetic field, rotation, porous medium permeability, kinematic viscoelasticity, the solute parameter and varying gravity field introduce oscillatory modes in the system, which were non-existent in their absence. The case of overstability is also considered wherein the sufficient conditions for the non-existence of overstability are obtained. The variation of the Rayleigh number with respect to the solute parameter, rotation, magnetic field and porous medium permeability for the stationary convection is also shown graphically.