A rotating Timoshenko beam free vibration problem is solved using the meshless local Petrov-Galerkin method. A locking-free shape function formulation is introduced with an improved radial basis ...function interpolation and the governing differential equations of the Timoshenko beam are used instead of the alternative formulation used by Cho and Atluri (2001). The locking-free approximation overcomes the problem of ill conditioning associated with the normal approximation. The radial basis functions satisfy the Kronercker delta property and make it easier to apply the essential boundary conditions. The mass matrix and the stiffness matrix are derived for the meshless local Petrov-Galerkin method. Results are validated for the fixed-free boundary condition with published literature.
In this article, we solve the free vibration problem of a rotating Euler-Bernoulli beam using the meshfree Galerkin method. Radial basis functions are used for interpolation. An improved formulation ...of the rotating Euler-Bernoulli beam free vibration problem with the Galerkin method is explained for the first time, which results into a symmetric stiffness matrix and gives a significant computational advantage over the formulation given in the existing literature. A conventional hp-version of Galerkin finite element method is used for comparison. Results are obtained at different non-dimensional rotating speeds of a rotating beam. Results show excellent agreement with the existing literature.
The epitaxial NiO layers deposited with higher fluence values are found to be strained, and the strain increases with the fluence values. The X-ray diffraction (XRD) profile taken from the ...synchrotron beam shows the presence of relaxed grains of NiO in addition to the strained grains, where the fraction of relaxed grains gradually increases with the fluence values. The presence of Pendellosung fringes in the XRD profile for the layers deposited at lower fluence values confirms good interfacial and crystalline qualities. As the fluence value is increased, the Pendellosung fringes start merging indicating relatively poor interfacial and crystalline qualities. The NiO layers are of epitaxial nature and grown along 111 direction with two domain structures that are in-plane rotated by 60° with respect to each other. The analysis of local structures from extended X-ray absorption fine structure measurements also indicates that the NiO lattice is strained at higher fluence values. The Ni–O bond distance does not change with the fluence values; however, Ni–Ni bond distance increases with the fluence values in corroboration with XRD results. The surface topography shows island growth of NiO at lower fluence values giving larger roughness, and these islands start merging with an increase in the fluence values leading to relatively smoother layers.
Free vibration problem of a rotating Euler-Bernoulli beam is solved with a truly meshless local Petrov-Galerkin method. Radial basis function and summation of two radial basis functions are used for ...interpolation. Radial basis function satisfies the Kronecker delta property and makes it simpler to apply the essential boundary conditions. Interpolation with summation of two radial basis functions increases the node carrying capacity within the sub-domain of the trial function and higher natural frequencies can be computed by selecting the complete domain as a sub-domain of the trial function. The mass and stiffness matrices are derived and numerical results for frequencies are obtained for a fixed-free beam and hinged-free beam simulating hingeless and articulated helicopter blades. Stiffness and mass distribution suitable for wind turbine blades are also considered. Results show an accurate match with existing literature.
Crystallographic and electronic structures of phase pure ternary solid solutions of Ni
Co
O (
= 0 to 1) have been studied using XRD, EXAFS and XAS measurements. The lattice parameter of the cubic ...rock-salt (RS) Ni
Co
O solid solutions increases linearly with increasing Co content and follows Vegard's law, in the complete composition range. A linear increase in the bond lengths (Ni/Co-O, Ni-Ni and Ni-Co) with "
", closely following the bond lengths determined from virtual crystal approximation (VCA), is observed, which implies that there is only a minimal local distortion of the lattice in the mixed crystal. The optical gap of the ternary solid solution determined from diffuse reflectivity measurements shows neither a linear variation with Co composition nor bowing, as observed in many ternary semiconductors. This trend in the variation of optical gaps is explained by probing the conduction band using XAS at the O K-edge. We have observed that the variation in the onset energy of the conduction band edge with "
" is very similar to the variation in the optical gap with "
", thus clearly indicating the dominant role played by the conduction band position in determining the optical gap. The variation in the intensities of the pre-edge peak in the XANES spectra measured at Ni and Co K-edges, and the L
peak in XAS spectra measured at Ni and Co L-edges, is found to depend on the unoccupied O 2p-metal-(Ni/Co) 3d hybridized states and the bond lengths.
In this paper, the flexural vibration in a cantilever beam having a transverse surface crack is considered. The modal frequency parameters are analytically computed for various crack locations and ...depths using a fracture mechanics based crack model. These computed modal frequencies are used to train a neural network to identify both the crack location and depth. The sensitivity of the modal frequencies to a crack increases when the crack is near the root and decreases as the crack moves to the free end of the cantilever beam. Because of the sensitive nature of this problem, a modular neural network approach is used. First, the crack location is identified with computed modal frequency parameters. Next, the crack depth is identified with computed modal frequency parameters and the identified crack location. A comparative study is made using the modular neural network architecture with two widely used neural networks, namely the multi-layer perceptron network and the radial basis function network. The proposed modular neural network method with a radial basis function network is found to perform better than the multi-layer perceptron network. In addition, the radial basis function network takes less computational time to train the network than the multi-layer perceptron network. This modular neural network architecture can be used as a non-destructive procedure for health monitoring of structures.
Increased emphasis on rotorcraft performance and operational capabilities has resulted in accurate computation of aerodynamic stability and control parameters. System identification is one such tool ...in which the model structure and parameters such as aerodynamic stability and control derivatives are derived. In the present work, the rotorcraft aerodynamic parameters are computed using radial basis function neural networks (RBFN) in the presence of both state and measurement noise. The effect of presence of outliers in the data is also considered. RBFN is found to give superior results compared to finite difference derivatives for noisy data.
On the basis of identified source of major bacterial infections at four agro-climatic zones in West Bengal the cost-effective biosecurity strategy was formulated for backyard poultry farmers. The aim ...of the present study was to assess the adoption. So, the study was aimed to detect the adoption level of the formulated biosecurity strategy to mitigate the Salmonella and Escherichia coliweek post-hatch period chicks were contamination level in the sources and its correlation with egg production in West Bengal.
A questionnaire was prepared querying regarding the biosecurity measures presently followed by the farmers, if any and egg production of their birds. Subsequent to the interview the formulated biosecurity strategy was conveyed. After 3 months, the interview with the same questionnaire was conducted to the same farmers to detect their adoption level.
The change in practices were noted in certain parameters which differs significantly (p<0.01 or p<0.05). As a consequence, the average egg production/flock was increased in 3 months after adoption of the strategy (618.2±37.77/flock) in comparison to last 3 months average before adoption of the strategy (495.3±30.00/flock) which also differs significantly (p<0.01).
The present study detected the implementation of the biosecurity strategy in backyard poultry farming in West Bengal can substantially benefit the farmers in terms of increased egg production.
Abstract
Oriented thin films of
β
-(Ga
1−
x
Fe
x
)
2
O
3
were deposited by radio frequency magnetron sputtering on c-Al
2
O
3
and GaN substrates. The itinerant character of the Fe 3d states forming ...the top of the valence band (VB) of the Fe-substituted
β
-Ga
2
O
3
thin films has been determined from resonant photoelectron spectroscopy. Further, the admixture of the itinerant and localized characters of these Fe 3d states has been obtained for larger binding energies; i.e. deeper in the VB. The bottom of the conduction band (CB) for
β
-(Ga
1−
x
Fe
x
)
2
O
3
has been also found to have strongly hybridized states involving Fe 3d and O 2p states compared to that of Ga 4s in pristine
β
-Ga
2
O
3
. This suggests that
β
-Ga
2
O
3
transforms from a band-like system to a charge-transfer system with Fe substitution. Furthermore, the bandgap red shifts with Fe composition, which has been found to be primarily related to the shift of the CB edge.
PDF
