Wyniki wyszukiwania - Biblioteka Nauki

1

Reflection at free surface in micropolar thermoelastic solid with two temperatures

100%

Sharma K.

International Journal of Applied Mechanics and Engineering

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2013

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tom Vol. 18, no. 1

217--234

EN

The present investigation is concerned with the effect of two temperatures on reflection coefficients in a micropolar thermoelastic solid half space. With two relaxation times, reflection of plane waves impinging obliquely at a plane interface of the micropolar generalized thermoelastic solid half space with two temperatures is investigated. The incident wave is assumed to be striking at the plane surface after propagating through the micropolar generalized thermoelastic solid with two temperatures. Amplitude ratios of the various reflected waves are obtained in closed form and it is found that these are functions of angle of incidence, frequency and are affected by the elastic properties of the media. The effect of two temperatures is shown on these amplitude ratios for a specific model.

2

Inventory model for deteriorating items under trade credit and inflation

63%

Saxena P. , Sharma K.

World Scientific News

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2018

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tom 113

3

Influence of heat sources and relaxation time on temperature distribution in tissues

63%

Sharma S. , Sharma K.

International Journal of Applied Mechanics and Engineering

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2014

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tom Vol. 19, no. 2

427--433

EN

In the present study, the temperature fluctuations in tissues based on Penne’s bio-heat transfer equation is investigated by applying the Laplace and Hankel transforms. To get the solution in a physical form, a numerical inversion technique has been applied. The temporal and spatial distribution of temperature is investigated with the effect of relaxation time and is presented graphically.

4

Synthesis and photoluminescence spectra of CdS and CdS/ZnO doped PVK nanocomposite films

63%

Kumar P. , Sharma K.

Materials Science Poland

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2018

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tom Vol. 36, No. 3

354--358

EN

Organic/inorganic hybrid materials consisting of quantum dots and conjugate polymers are important for the application in light emitting devices. In the present work, we have studied the effect of CdS and CdS/ZnO nanoparticle addition on the structure and fluorescence properties of spin coated PVK (poly(N-vinyl carbozole)) nanocomposite films. CdS nanoparticles were synthesized by simple co-precipitation technique and ZnO shell was grown on the CdS nanoparticles by simple wet chemical approach. The nanoparticles and the hybrid nanocomposites have been characterized by using XRD, SEM, FT-IR, optical absorption and fluorescence spectroscopic techniques. The absorption peak for pure PVK remains at 345.5 nm accompanied with minor hump ~480 nm resulting from the incorporation of nanoparticles. It has been observed that the addition of nanoparticles to the hybrid material results in the enhancement of fluorescence intensity at 410 nm to 450 nm spectral regions. These results are important for the development of new light emitting devices at low fabrication costs.

5

Pure intrusion of a mandibular canine with segmented arch in lingual orthodontics: A numerical study with 3-dimensional finite element analysis

51%

Thote A. M. , Sharma K. , Uddanwadiker R. V. , Shrivastava S.

Biocybernetics and Biomedical Engineering

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2017

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tom Vol. 37, no. 3

590--598

EN

Objective: Approximately 50% patients with a deep bite possess anatomically extruded mandibular canines. The objective of this study was to specify the required toe (θ) of the vertical segment of a cantilever from the distal aspect to achieve pure intrusion of a mandibular canine with a segmented arch in lingual orthodontics. Additionally, the optimum magnitude of the required intrusive force by a cantilever was determined assuming non-linear, hyper-elastic behaviour of periodontal ligament (PDL). Methods: The geometrical model of a mandibular canine tooth was developed and the mathematical equation was devised to evaluate θ (positive value: toe-in, negative value: toe-out) based on certain input parameters. To verify this numerical study by finite element analysis (FEA), total eight different positions of point of force application (Pf) on bracket top (occlusal) surface were considered based on different values of input parameters. Results: The results were displayed in terms of nature of tooth movement and Von-Mises (equivalent) stresses generated in the PDL. Additionally, the optimum magnitude of the required intrusive force within the biological limit of a mandibular canine was determined from FEA considering the strength of PDL and factor of safety. Conclusions: The numerical study was developed to compute the value of required toe angle (θ) of the vertical segment of a cantilever for different morphologies of a mandibular canine as well as different positions of Pf. From FEA, the optimum range of an intrusive force within the biological limit of a mandibular canine was found to be 20–30 g.

6

Complexation Behaviour of 5(2"-Hydroxyphenyl)-3-phenylpyrazoline with Some Metallic Moieties

51%

Tripathi U. , Sharma K. , Chaturvedi A. , Sharma T.

Polish Journal of Chemistry

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2003

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tom Vol. 77 / nr 1

109-115

7

MeCP2 in central nervous system glial cells: current updates

51%

Sharma K. , Singh J. , Frost E. E. , Pillai P.

Acta Neurobiologiae Experimentalis

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2018

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tom 78

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nr 1

EN

Methyl-CpG binding protein 2 (MeCP2) is an epigenetic regulator, which preferentially binds to methylated CpG dinucleotides in DNA. MeCP2 mutations have been linked to Rett syndrome, a neurodevelopmental disorder characterized by severe intellectual disability in females. Earlier studies indicated that loss of MeCP2 function in neuronal cells was the sole cause of Rett syndrome. Subsequent studies have linked MeCP2 expression in CNS glial cells to Rett syndrome pathogenesis. In this review, we have discussed the role of MeCP2 in glial subtypes, astrocytes, oligodendrocytes and microglia, and how loss of MeCP2 function in these cells has a profound influence on both glial and neuronal function.

8

Effect of nanocrystals concentration on optical and luminescent properties of PVK:ZnSe nanocomposites

51%

Sharma K. , Kumar P. , Verma G.

Materials Science Poland

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2018

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tom Vol. 36, No. 3

494--500

EN

This work presents a systematic study of the effect of ZnSe nanocrystals (NCs) concentration on the optical and luminescent properties of poly N-vinylcarbazole (PVK) polymer nanocomposites. The ZnSe nanocrystals were synthesized by a simple co-precipitation chemical route, while PVK:ZnSe nanocomposite films were fabricated using the spin coating technique. The samples were characterized by XRD, TEM, SEM, UV-Vis and fluorescence techniques. The X-ray diffraction and TEM studies confirmed the particle size, microstructure and spherical shape of the synthesized nanocrystals. The ZnSe nanocrystals in PVK caused a decrease in optical gap with increasing concentration of nanocrystals. The emission spectra exhibited augmentation in intensity up to 70 wt.% of nanoparticles while further addition resulted in a decrease in luminescence. The structure-property relationships obtained for the present system are important for developing low cost illumination devices.

9

Effect of point source and heterogeneity on the propagation of SH-Waves in a viscoelastic layer over a viscoelastic half space

51%

Chattopadhyay A. , Gupta S. , Kumari P. , Sharma K.

Acta Geophysica

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2012

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tom Vol. 60, no. 1

119-139

EN

The present paper is concerned with the propagation of shear waves in a homogeneous viscoelastic isotropic layer lying over a semi-infinite heterogeneous viscoelastic isotropic half-space due to point source. The inhomogeneity parameters associated to rigidity, internal friction and density are assumed to be functions of depth. The dispersion equation of shear waves has been obtained using Green's function technique. The dimensionless angular frequency has been plotted against dimensionless wave number for different values of inhomogeneity parameters. The effects of inhomogeneity have been shown in the dispersion curves. graphical user interface (GUI) software in MATLAB has been developed to show the effect of various inhomogeneity parameters on angular frequency. The topic can be of interest for geophysical applications in propagation of shear waves on the Earth’s crust.

10

The physiology of extremely desiccated Brassica juncea [L] seeds

51%

Khattra S. , Sharma K. , Singh G.

Acta Agrobotanica

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1993

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tom 46

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nr 2

5-13

EN

Seeds of four raya cvs., viz. RL 1359, RLM 198, RLM 619 and RLM 514 were desiccated for 2, 7,15 and 45 days wchich led to different levels of seed moisture. Data on germination capacity speed of germination, seedling dry weight, electrical conductance, dehydrogenase activity and seed storage behaviour for up to two years after desiccation were recorded. Based on this data, cvs. RL 1359 and RLM 514 were found to be tolerant to desiccation to as low as 0.73 and 1.16 per cent seed moisture levels, respectively. Seeds of RLM 198 tolerated desiccation up to 2.28 per cent seed moisture. However, RLM 619 seeds showed desiccation injuries in seedling dry weight, electrical conductance and speed of germination at moisture levels below 5.67 per cent.

PL

Nasiona czterech odmian: RL 1359, RLM 198, RLM 619 i RLM 514 suszono przez 2. 7, 15 i 45 dni w celu uzyskania różnego poziomu wilgotności nasion. Badano zdolność i szybkość kiełkowania, suchą masę kiełków, stopień przewodnictwa elektrycznego, aktywność dehydrogenazy i zachowanie nasion podczas dwuletniego okresu przechowywania. Na podstawie tych danych ustalono, że odmiany RL 1359, RLM 514 są tolerancyjne na wysuszenie odpowiednio do 0,73 i 1,16 % wilgotności. Nasiona odmiany RLM 198 tolerują wysuszenie do 2,28 %. Nasiona zaś odmiany RLM 619 przy poziomie wilgotności poniżej 5,67 % reagują obniżoną masą kiełków, mniejszą siłą kiełkowania i gorszym przewodnictwem.