Theoretical study of the effect of size, pressure and temperature on nanomaterials
KrishiKosh
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Title |
Theoretical study of the effect of size, pressure and temperature on nanomaterials
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Creator |
Raghuvesh Kumar
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Contributor |
Munish Kumar
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Subject |
pressure, temperature, nanomaterials, models, nanotechnology
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Description |
Thesis-PhD
We have developed the theoretical formulation to study the effect of the size, pressure and temperature on nanomaterials. We have studied the size dependence of bulk modulus, Young modulus, coefficient of volume thermal expansion, cohesive energy, melting temperature, Debye temperature and specific heat of different types of nanomaterials. The results obtained are found to present a good agreement with the available experimental data. We also developed the formulation to study the effect of pressure and temperature on nanomaterials by unifying two different approaches. We used our unified theory to study the effect of pressure (at constant temperature), the effect of temperature (at constant pressure) as well as the combined effect of pressure and temperature. The results obtained are found to present a good agreement with the experimental data. This supports the validity of the formulation developed in the present work. The values of pressure dependence of bulk modulus obtained from the corresponding relation have also been studied. A critical analysis of the model has been presented which demonstrates that Anderson-Gruneisen parameter is independent of pressure for the pressure range considered in the present thesis. We have extended the theory to compute the temperature dependence of volume for different nanomaterials. It is very interesting to mention that relation reported by Hu et al. may be obtained from the present model. Thus, the formulation developed in the present work, gets strong support from the studies of Hu et al. These authors also discussed that it is not possible to compute thermal expansion due to the lack of input data. Moreover, in the present thesis, we have refined the theory to make it convenient for the application purposes. Thus, the present formulation is a significant advancement as discussed by Hu et al. There is a good agreement between theory and experiment. We have also extended our formulation to study the nanomaterials under varying conditions of pressure and temperature both. There is a good agreement between theory and available experimental data. There is a shift of the isotherm but small. This shows the effect of temperature on compression behavior of nanosystem. The formulation developed in the present thesis has also been extended to study the effect of pressure on the second order elastic constants of nanomaterials. This needs the corresponding values of V/V0 as input data which have been evaluated using the present model. There is a good agreement between theory and experiment for the materials considered in the present thesis. |
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Date |
2016-08-16T14:24:02Z
2016-08-16T14:24:02Z 2011-05 |
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Type |
Thesis
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Identifier |
http://krishikosh.egranth.ac.in/handle/1/72602
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Language |
en
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Format |
application/pdf
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Publisher |
G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
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