Wyniki wyszukiwania - Biblioteka Nauki

1

Modelling of thermoelastic Lamb waves in a plate bordered with viscous fluid of varying temperature

100%

Sharma J. N. , Sharma R.

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tom Vol. 15, no 1

217-236

EN

The propagation of thermoelastic waves in a homogeneous isotropic, thermally conducting plate bordered with layers (or half-spaces) of a viscous fluid on both sides is investigated. The problem has been modeled by employing non classical theory of thermoelasticity to carry the investigation. The secular equations for governing the symmetric and antisymmetric wave motion of the plate, in completely separate terms, are derived. The results in the context of classical conventional coupled and uncoupled theories of thermoelasticity in case of viscous and inviscid fluid loadings have been obtained as particular cases from the present analysis. The regions of the secular equation, waves of short wavelength and waves of long wavelength have also been discussed and deduced. Finally, in order to illustrate the analytical results, the numerical solution is carried out for an aluminum-epoxy composite material plate bordered with layers (or half-spaces) of light and heavy water. The results have been deduced and compared with the existing ones in relevant publications available in the literature at various stages of this work.

2

Insights into fluoride-induced oxidative stress and antioxidant defences in plants

100%

Sharma R. , Kaur R.

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nr 10

3

100%

Sharma R. , Singh R.

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tom Vol. 20, No. 2

363--373

EN

The main aim of this paper was to identify job stressors, gender responses and association of psychosocial work stressors with prevalence of work related musculoskeletal disorders (MSDs) among foundry workers. The data were obtained with ergonomics checklist using Likert scale. The results of this study showed a high prevalence of MSDs among workers. The male workers were more prone to pain in neck while the female workers were more prone to MSDs in upper back and shoulders. Correlation analysis showed significant relationship of dimensions of work aspects with pain and discomfort. It proved that the work-related MSDs are the results of interaction of multiple stressors associated with work and work environment, and other personal factors. ANOVA indicated that the perception of work aspects as stressors differed significantly between male and female workers.

4

Development of validation of RP-HPLC method for simultaneous determination of pyridoxine hydrochloride, isoniazid, pyrazinamide and rifampicin in pharmaceutical formulation

100%

Dhal S. K. , Sharma R.

Chemia Analityczna

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2009

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tom Vol. 54, No. 6

1487-1500

EN

A simple, rapid and precise liquid chromatographic method for simultaneous determination of pyridoxine hydrochloride. isomazid, pyrazmamide and rifampicin in a tablet dosage form has been developed Chromatographic analysis was performed on a 250 x 4.6 mm I.D. C|8 column packed with 5 μm-in-size particles applying gradient elution with a mobile phase composed of acetonitrile (A) and 15 mmol L-1 potassium dihydrogen phosphate buffer of pH adjusted to 4.0 J: 0.1 with o-phosphoric acid (B). A:B ratio was 11:89 v/v for the initial 4.5 min. and then it was maintained at 50:50 v/v; the flow rate was 1 mL min-1UV detection was performed at 235 nm. The total run time was 20 mm. Retention times for pyridoxine hydrochloride, isoniazid, pyrazmamide and rifampicin were 3.687, 4.113, 5.041 and 12.829 min, respectively The method was validated with respect to linearity, accuracy, . precision, specificity and sensitivity in accordance with ICH guidelines. Limits of detection were 0.043. 0.063. 0.036 and 0.059 μg mL--1'and limits of quantification were 0.13, 0.19, 0.11 and 0.18 μg ml, ' for pyridoxine hydrochloride, isoniazid, pyrazinamide and rifampicin, respectively. High recovery and low coefficients of variance confirmed the suitability of the method for the simultaneous analysis of the four considered drugs.

PL

Opracowano prostą, szybką i precyzyjną procedurę jednoczesnego oznaczania chlorowodorku pirydoksyny, izoniazydu, pirazynamidu i rifampicyny w tabletkach za pomocą chromatografii cieczowej. Analizę chromatograficzną prowadzono przy użyciu kolumny 250 x 4,6 mm. napełnionej faząC18 o wielkości cząstek wynoszącej 5 urn. Zastosowano gradient fazy ruchomej składającej się z acetonitrylu (A) i buforu w postaci fosforanu dihydropotasowego o stężeniu 15 mmol L-1 i pH = 4 š 0, l ustalonego za pomocą kwasu o-fosforowego (B). Stosunek A i B wynosił 11:89 v/v przez 45 min, następnie był utrzymywany stosunek 50:50 v/v. Przepływ fazy ruchomej wynosił l mL min"1. Całkowity czas rozdzielania składników mieszaniny wynosił 20 min. Detekcję UV prowadzono przy 235 nm. Czasy retencji chlorowodorku pirydoksyny, izoniazydu, pirazynamidu i rifampicyny wynosiły odpowiednio 3.687; 4,113; 5,041 i 12,829 min. Opracowaną procedurę walidowano uwzględniając liniowość, dokładność, precyzję, specyficzność i czułość, zgodnie z zaleceniami Międzynarodowej Konferencji Harmonizacyjnej (ICH). Wykrywalności wynosiły 0.043; 0.063; 0.036 i 0,059μg mL-1a oznaczalności 0,13; 0,19; 0,11 i 0,18 μg mL-1 odpowiednio dla chlorowodorku pirydoksyny, izoniazydu, pirazynamidu i rifampicyny. Wysoki odzysk i małe współczynniki wariancji potwierdziły przydatność metody do jednoczesnej analizy czterech leków.

5

Toxoplasma gondii in chickens (Gallus domesticus) from North India

80%

Thakur R. , Sharma R. , Singh Aulakh R. , Singh B. B.

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nr 1

6

Magneto-polar fluid flow through a porous medium of variable permeability in slip flow regime

80%

Gaur P. K. , Jha A. K. , Sharma R.

International Journal of Applied Mechanics and Engineering

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2016

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tom Vol. 21, no. 2

323--339

EN

A theoretical study is carried out to obtain an analytical solution of free convective heat transfer for the flow of a polar fluid through a porous medium with variable permeability bounded by a semi-infinite vertical plate in a slip flow regime. A uniform magnetic field acts perpendicular to the porous surface. The free stream velocity follows an exponentially decreasing small perturbation law. Using the approximate method the expressions for the velocity, microrotation, and temperature are obtained. Further, the results of the skin friction coefficient, the couple stress coefficient and the rate of heat transfer at the wall are presented with various values of fluid properties and flow conditions.

7

Generalized Rayleigh waves in thermoelastic solids under viscous fluid loading

80%

Sharma J. N. , Sharma R. , Sharma Y. D.

International Journal of Applied Mechanics and Engineering

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2008

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tom Vol. 13, no 1

217-238

EN

The paper is aimed to study the propagation of Rayleigh surface waves in a homogeneous isotropic, thermally condueting, and elastic solid halfspace underlying a viscous liquid semi space in the context of generalized theories of thermoelasticity. The investigation is based on modelling the viscous liquid as a hypothetical solid in addition to conduction-convection condition of heat transfer at the interface. After developing the mathematical model, boundary conditions and formal solutions, the secular equations for a thermoelastic solid in closed form and isolated mathematical conditions for generalized Rayleigh waves (Stoneley waves), in complete forms are derived. The amplitude ratios of solid and liquid displacements and temperature change on the surface (interface) are obtained analytically. The surface particle motion has also been discussed and found to be elliptical. The semi-major and semi-minor axes, eccentricity and inclination of major axes with the wave normal are computed analytically and analyzed numerically. The results have been deduced and compared with the relevant publications available in the literature at the appropriate stages of the work. Finally, the numerical solution is carried out for an aluminum-epoxy composite material solid (half space) underlying water, in the case of both light and heavy semi spaces. The dispersion curves, attenuation coefficient profiles and amplitude ratios of surface displacements, temperature change in the solid half space for generalized Rayleigh waves are presented and illustrated graphically in order to illustrate and compare the theoretical results. The theory and numerical computations are found to be in close agreement. The present analysis is useful in electronics and navigation applications.

8

Thermosolutal instability of Walters' rotating fluid (Model B') in porous medium

80%

Sharma R. , Sunil , Chand S.

Archives of Mechanics

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1999

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tom Vol. 51, nr 2

181-191

EN

The thermosolutal instability of Walters' (Model B') fluid in porous medium is considered in the presence of uniform vertical rotation. For the case of stationary convection, the stable solute gradient and rotation have stabilizing effects on the system, whereas the medium permeability has a destabilizing (or stabilizing) effect on the system under certain conditions. The dispersion relation is also analysed numerically. It has also been shown that as rotation parameter increases, the stabilizing range of medium also increases. The kinematic viscoelasticity has no effect on the stationary convection. The stable solute gradient, rotation, porosity and kinematic viscoelasticity introduce oscillatory modes in the system, which did not occur in their absence. The sufficient conditions for the non-existance of overstability are also obtained.

9

Green pod culture and rapid micropropagation of Dendrobium chrysanthum Wall. - A horticultural and medicinal orchid

80%

Kumar De K. , Majumdar S. , Sharma R. , Sharma B.

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nr 1

10

Investigations of highly conducting and transparent Sc doped ZnO films grown by the sol-gel process

80%

Sharma R. , Shishodia P. K. , Wakahara A. , Mehra R. M.

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tom Vol. 27, No. 1

225--237

EN

Highly transparent and conductive scandium doped zinc oxide (ZnO/Sc) films were prepared on Corning glass 7059 substrates by the sol-gel technique. The influence of scandium concentration (0-1.5 wt. %) and annealing temperature (300-500 °C) on the structural, optical and electrical properties was investigated. The average transmittance was found to be above 89% in the visible region. ZnO/Sc film having 0.5 wt. % of Sc and annealed at 400 °C exhibited a minimum resistivity of 3.52×10-4 ohmocm. The surface morphology of these films examined by SEM and AFM revealed formation of nano rods.

11

Axisymmetric vibration for micropolar porous thermoelastic circular plate

80%

Kumar R. , Kaushal P. , Sharma R.

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tom Vol. 22, no. 3

583--600

EN

The present investigation is concerned with a two dimensional axisymmetric problem in a homogeneous isotropic micropolar porous thermoelastic circular plate by using the eigen value approach. The Laplace and Hankel transform are used to solve the problem. The expression of displacements, microrotation, volume fraction field, temperature distribution and stresses are obtained in the transformed domain subjected to thermomechanical sources. A computer algorithm is developed for numerical computations. To obtain the resulting quantities in a physical domain, a numerical inversion technique is used. The resulting quantities are depicted graphically for a specific model. Some special cases are also deduced.

12

Effects of Hall current on unsteady hydromagnetic free convection flow past an impulsively moving vertical plate with Newtonian heating

80%

Seth G. S. , Sarkar S. , Sharma R.

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tom Vol. 21, no. 1

187--203

EN

An investigation of unsteady hydromagnetic free convection flow of a viscous, incompressible and electrically conducting fluid past an impulsively moving vertical plate with Newtonian surface heating embedded in a porous medium taking into account the effects of Hall current is carried out. The governing partial differential equations are first subjected to the Laplace transformation and then inverted numerically using INVLAP routine of Matlab. The governing partial differential equations are also solved numerically by the Crank-Nicolson implicit finite difference scheme and a comparison has been provided between the two solutions. The numerical solutions for velocity and temperature are plotted graphically whereas the numerical results of skin friction and the Nusselt number are presented in tabular form for various parameters of interest. The present solution in special case is compared with a previously obtained solution and is found to be in excellent agreement.

13

Common fixed point theorems via generalized condition (B) in quasi-partial metric space and applications

80%

Tomar A. , Beloul S. , Sharma R. , Upadhyay S.

Demonstratio Mathematica

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2017

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tom Vol. 50, nr 1

278--298

EN

The aim of this paper is to introduce generalized condition (B) in a quasi-partial metric space acknowledging the notion of Künzi et al. [Künzi H.-P. A., Pajoohesh H., Schellekens M. P., Partial quasi-metrics, Theoret. Comput. Sci., 2006, 365, 237-246] and Karapinar et al. [Karapinar E., Erhan M., Öztürk A., Fixed point theorems on quasi-partial metric spaces, Math. Comput. Modelling, 2013, 57, 2442-2448] and to establish coincidence and common fixed point theorems for two weakly compatible pairs of self mappings. In the sequel we also answer a rmatively two open problems posed by Abbas, Babu and Alemayehu [Abbas M., Babu G. V. R., Alemayehu G. N., On common fixed points of weakly compatible mappings satisfying generalized condition (B), Filomat, 2011, 25(2), 9-19]. Further in the setting of a quasi-partial metric space, the results obtained are utilized to establish the existence and uniqueness of a solution of the integral equation and the functional equation arising in dynamic programming. Our results are also justified by explanatory examples supported with pictographic validations to demonstrate the authenticity of the postulates.

14

Transport of glutathione-conjugates in human erythrocytes

80%

Sharma R. , Awasthi S. , Zimniak P. , Awasthi Y. C.

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2000

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tom 47

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nr 3

EN

The last step of detoxification of both endogenous and environmental toxicants is typically a conjugation that produces a bulky hydrophilic molecule. The excretion of such conjugates out of cells is of sufficient biological importance to have led to the evolution of ATP-driven export pumps for this purpose. The substrate specificity of such transporters is broad, and in some cases it has been shown to include not only anionic conjugates but also neutral or weakly cationic drugs. In the present article, we review the molecular identity, functional and structural characteristics of these pumps, mainly on the example of human erythrocytes, and discuss their physiological role in detoxification and in the multidrug resistance phenotype of cancer cells.

15

Conservation of the endangered medicinal plant Picrorhiza kurroa through in vitro multiple shoot regeneration

71%

Chaudhary V. , Singh S. , Sharma R. , Singh A. , Sharma N.

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nr 3

16

Effect of pruning Intensities on the performance of fruit plants under mid-hill condition of Eastern Himalayas: case study on Guava

71%

Bhagawati R. , Bhagawati K. , Choudhary V. K. , Rajkowa D. J. , Sharma R.

International Letters of Natural Sciences

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2015

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tom 46

EN

Current study was undertaken to highlight the effect of pruning on improving vigor of old orchards and increasing performance in terms of fruit yield and quality under water and nutrient stressed condition of mid hills of Eastern Himalaya. Guava was taken for the case study and all the physical and chemical properties of the fruits and other attributes of plant were evaluated using standard methods under three pruning intensities (light, moderate and severe) and no pruning. The emergence of bud was earliest in severe pruning, number of buds per shoot was highest with light pruning and cumulative lengths of new shoots were found to be highest in severe pruning. Fruit yield, size and weight were found to increase with pruning intensities and lowest in case of no pruning. Regarding chemical properties, total soluble solids and total sugar found to increase with enhanced pruning severity and least in case of no pruning. Acidity was found to be highest with no pruning and decrease with increase in pruning intensities. Overall pruning found to have rejuvenating impact on aged trees due to better light interception leading to better photosynthetic rate, better nutrient and water supply with reduced canopy and better quality yields.

17

Compression loading behaviour of sunflower seeds and kernels

71%

Selvam T. A. , Manikantan M. R. , Chand T. , Sharma R. , Seerangurayar T.

International Agrophysics

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2014

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tom 28

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nr 4

EN

The present study was carried out to investigate the compression loading behaviour of five Indian sunflower varieties (NIRMAL-196, NIRMAL-303, CO-2, KBSH-41, and PSH-996) under four different moisture levels (6-18% d.b). The initial cracking force, mean rupture force, and rupture energy were measured as a function of moisture content. The observed results showed that the initial cracking force decreased linearly with an increase in moisture content for all varieties. The mean rupture force also decreased linearly with an increase in moisture content. However, the rupture energy was found to be increasing linearly for seed and kernel with moisture content. NIRMAL-196 and PSH-996 had maximum and minimum values of all the attributes studied for both seed and kernel, respectively. The values of all the studied attributes were higher for seed than kernel of all the varieties at all moisture levels. There was a significant effect of moisture and variety on compression loading behaviour.

18

Lipid peroxidation and cell cycle signalling: 4-hydroxynonenal, a key molecule in stress mediated signalling

70%

Yang Y. , Sharma R. , Sharma A. , Awasthi S. , Awasthi Y. C.

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nr 2

EN

Role of lipid peroxidation products, particularly 4-hydroxynonenal (4-HNE) in cell cycle signaling is becoming increasingly clear. In this article, recent studies suggesting an important role of 4-HNE in stress mediated signaling for apoptosis are critically evaluated. Evidence demonstrating the modulation of UV, oxidative stress, and chemical stress mediated apoptosis by blocking lipid peroxidation by the a-class glutathione S-transferases (GSTs) is presented which suggest an important role of these enzymes in protection against oxidative stress and a role of lipid peroxidation products in stress mediated signaling. Overexpression of 4-HNE metabolizing GSTs (mGSTA4-4, hGSTA4-4, or hGST5.8) protects cells against 4-HNE, oxidative stress (H2O2 or xanthine/xanthine oxidase), and UV-A mediated apoptosis by blocking JNK and caspase activation suggesting a role of 4-HNE in the mechanisms of apoptosis caused by these stress factors. The intracellular concentration of 4-HNE appears to be crucial for the nature of cell cycle signaling and may be a determinant for the signaling for differentiation, proliferation, transformation, or apoptosis. The intracellular concentrations of 4-HNE are regulated through a coordinated action of GSTs (GSTA4-4 and hGST5.8) which conjugate 4-HNE to GSH to form the conjugate (GS-HNE) and the transporter 76 kDa Ral-binding GTPase activating protein (RLIP76), which catalyze ATP-dependent transport of GS-HNE. A mild stress caused by heat, UV-A, or H2O2 with no apparent effect on the cells in culture causes a rapid, transient induction of hGST5.8 and RLIP76. These stress preconditioned cells acquire ability to metabolize and exclude 4-HNE at an accelerated pace and acquire relative resistance to apoptosis by UV and oxidative stress as compared to unconditioned control cells. This resistance of stress preconditioned cells can be abrogated by coating the cells with anti-RLIP76 antibodies which block the transport of GS-HNE. These studies and previous reports discussed in this article strongly suggest a key role of 4-HNE in stress mediated signaling.

19

Photocatalytic degradation of ampicillin using silver nanoparticles biosynthesised by Pleurotus ostreatus

61%

Jassal P. S. , Khajuria R. , Sharma R. , Debnath P. , Verma S. , Johnson A. , Kumar S.

BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology

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2020

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tom 101

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nr 1

20

Spectroscopic investigations of polycrystalline InxSb20−xAg10Se70 (0 6 x 6 15) multicomponent chalcogenides

61%

Sharma R. , Sharma S. , Kumar P. , Chander R. , Thangaraj R. , Mian M.

Materials Science Poland

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2016

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tom Vol. 34, No. 4

794--799

EN

The composition dependence of physical properties of chalcogenides has recently been studied for their phase change properties and energy conversion. In the present work, we report the structure, composition, optical and Raman spectroscopy results for bulk polycrystalline InxSb20-xAg10Se70 (0 ≤ × ≤ 15) samples. The phase quantification and composition have been studied by using XRD and EDX techniques. The alloy composition up to 5 at.% of indium resulted in crystallization of AgSbSe2, while further increase in In content favored the formation of another chalcopyrite AgInSe2 phase yielding the solid solutions for this alloy system. A decrease in band gap up to x = 5 followed by its increase with an increase in indium concentration has been observed. The variations in shape and position of characteristic Raman bands has been used for understanding the structural modifications of the network with the variation in indium content.