Studies on the Biology and Predatory Behaviour of Eocanthecona furcellata (Wolff.) Predating on Spilarctia obliqua (Walk.) in Mulberry Plantation

Kumar, Vineet,Morrison, M.N.,Rajadurai, S.,Babu, A.M.,Thiagarajan, V.,Datta, R.K. Korean Society of Sericultural Science 2001 International Journal of Industrial Entomology Vol.2 No.2

The stink bug, Eocanthecona furcellata (Wolff.) is a natural and potential biocontrol agent of Spilarctia obliqua (Walk.). The present investigation reveals the biology, predatory efficiency and reproductive parameters of the predator which feeds on S. obliqua caterpillars in mulberry plantation. In order to find out the role of prey sine on the biology of the predators the predatory insects were separately fed with small and large caterpillars of S. obliqua. The incubation period of the eggs of E. furcellata was 8.37${\pm}$0.44 days, while the nymphal duration varied as per the prey sine. The predator when supplied with small larvae of prey, consumed 61.1 larvae and completed nymphal stage in 19.9 days; while those fed with larger prey, consumed 36.1 larvae and completed their nymphal stage in 21.55 days. The prey size also influences the reproductive parameters of the predator, The adult female predator is more voracious feeder than the adult male and consumed 41.9${\pm}$0.64 small larvae and 42.2${\pm}$0.87 large larvae during their life span. The longevity of male and female was observed as 20.7 and 29.4 days respectively. Visualization of the predator as well as the movement of the prey increases the predatory efficiency. Scanning electron microscopic studies on the feeding part explain its support in effective predation. Field observations indicated a drastic fall in the incidence of the mulberry pest, S. obliqua with the increased population E. furcellata in mulberry plantation.

Dynamic instability analysis of laminated composite stiffened shell panels subjected to in-plane harmonic edge loading

S. N. Patel,P. K. Datta,A. H. Sheikh 국제구조공학회 2006 Structural Engineering and Mechanics, An Int'l Jou Vol.22 No.4

Aeroelastic Instability of Flexible Rocket Bodies on the Basis of a Simplified Mechanical Model

S. K. Jatav,P.K. Datta 한국항공우주학회 2019 International Journal of Aeronautical and Space Sc Vol.20 No.2

The present paper deals with the applicability of simplified mechanical models to discuss the aeroelastic instability behavior of flexible rocket bodies. A suitable mechanical model to demonstrate body divergence and flutter has been discussed and the stability analysis of the model has been presented. The flutter criterion requires a computation of the characteristic polynomial. Sylvester’s dialytic method of elimination is used to compute the required discriminant. A mechanical model composed of three bars, connected together by two elastic rotational springs, having five degrees-of-freedom is chosen for demonstrating both divergence and flutter instabilities. Effects of mass distribution, stiffness distribution, and location of stabilizer fin on instability behavior are discussed.

Aeroelastic Behaviour of Aerospace Structural Elements with Follower Force: A Review

Datta, P.K.,Biswas, S. The Korean Society for Aeronautical and Space Scie 2011 International Journal of Aeronautical and Space Sc Vol.12 No.2

In general, forces acting on aerospace structures can be divided into two categories-a) conservative forces and b) nonconservative forces. Aeroelastic effects occur due to highly flexible nature of the structure, coupled with the unsteady aerodynamic forces, causing unbounded static deflection (divergence) and dynamic oscillations (flutter). Flexible wing panels subjected to jet thrust and missile type of structures under end rocket thrust are nonconservative systems. Here the structural elements are subjected to follower kind of forces; as the end thrust follow the deformed shape of the flexible structure. When a structure is under a constant follower force whose direction changes according to the deformation of the structure, it may undergo static instability (divergence) where transverse natural frequencies merge into zero and dynamic instability (flutter), where two natural frequencies coincide with each other resulting in the amplitude of vibration growing without bound. However, when the follower forces are pulsating in nature, another kind of dynamic instability is also seen. If certain conditions are satisfied between the driving frequency and the transverse natural frequency, then dynamic instability called 'parametric resonance' occurs and the amplitude of transverse vibration increases without bound. The present review paper will discuss the aeroelastic behaviour of aerospace structures under nonconservative forces.

Performance Evaluation of Different Averaging based Filter Designs Using Digital Signal Processor and its Synthesis on FPGA

S. K. Shome,S. R. K. Vadali,U. Datta,S. Sen,A. Mukherjee 보안공학연구지원센터(IJSIP) 2012 International Journal of Signal Processing, Image Vol.5 No.3

Breeding of New Productive Bivoltine Hybrid, CSR12 $\times$ CSR6 of Silkworm Bombyx mori L.

Datta, R.K.,Basavaraja, H.K.,Reddy, N.Mal,Kumar, S.Nirmal,Kumar, N.Suresh,Babu, M.Ramesh,Ahsan, M.M.,Jayaswal, K.P. Korean Society of Sericultural Science 2001 International Journal of Industrial Entomology Vol.3 No.2

With an objective of evolving quantitatively and qualitatively superior bivoltine breeds/hybrids of silkworm Bombyx mori L. for tropical conditions, breeding work was initiated in Central Sericultural Research and Training Institute, Mysore during 1992 by utilizing two Japanese hybrids namely BNl8$\times$BCS25 and Shunrei$\times$Shogetsu along with Indian evolved breed, KA. The breed CSR12 which is characterized with sex-limited larval marking and white oval cocoons was evolved from the Japanese hybrid BNl8 ${\times}$ BCS25 by crossing with KA, while the breed CSR6 which is characterized with normal marking (marked larvae) and white dumbbell cocoons was extracted from the Japanese commercial hybrid Shunrei${\times}$Shogetsu through continuous inbreeding coupled with selection. After fixation, these breeds along with other newly evolved breeds were subjected to hybrid study under optimum environmental conditions in the laboratory for expression of full potential of the genotypes. These hybrids were evaluated by Multiple Trait Evaluation Index (Mano et al., 1993). The hybrid CSR12${\times}$CSR6 was selected based multiple trait evaluation index value. The hybrid CSR12$\times$CSR6 recorded survival of 96.0%, shell weight of 50.0 cg, shell ratio of 24.3%, raw silk percentage of 19.6, filament length of 1,216 m, boil off loss of 22.4% and renditta of 5.1. On the other hand, the control hybrid (KA ${\times}$ NB4D2) has recorded survival of 90.6%, shell weight of 42.1 cg, shell ratio of 20.4%, raw silk percentage of 15.9, filament length of 999 m, boil off loss of 24.8% and renditta of 6.3. The hybrid CSR12$\times$CSR6 was authorized during 1997 by Central Silk Board, Government of India for commercial exploitation during favourable months based on national level race authorization test.

Shape Optimization of Damaged Columns Subjected to Conservative and Non-Conservative Forces

S. K. Jatav,P. K. Datta 한국항공우주학회 2014 International Journal of Aeronautical and Space Sc Vol.15 No.1

This paper deals with the development of a realistic shape optimization of damaged columns that are subjected to conservative and non-conservative forces, using the Genetic Algorithm (GA). The analysis is based on the design of the most optimized shape of the column under the constraint of constant weight, considering the Static, Vibrational, and Flutter characteristics. Under the action of conservative and non-conservative longitudinal forces, an elastic column loses its stability. A numerical analysis based on FEM has been performed on a uniform damaged column, to compute the fundamental buckling load, vibration frequency, and flutter load, under various end restraints. An optimization search based on the Genetic Algorithm is then executed, to find the optimal shape design of the column. The optimized column references the one having the highest buckling load, highest vibration frequency, and highest flutter load, among all the possible shapes of the column, for a given volume. A comparison is then made between the values obtained for the optimized damaged column, and those obtained for the optimized undamaged column. The comparison reveals that the incorporation of damage in the column alters its optimal shape to only a certain extent. Also, the critical load and frequency values for the optimized damaged column are comparatively low, compared with those obtained for the optimized undamaged column. However, these results hold true only for moderate-intensity damage cases. For high intensity damage, the optimal shape may not remain the same, and may vary, according to the severity of damage.

Synthesis of large monodisperse ETS-10 crystals and observation of quantum confinement effects from very long titanate quantum wires

Datta, S.J.,Yoon, K.B. Elsevier Science Publishers 2013 CATALYSIS TODAY - Vol.204 No.-

Synthetic conditions to produce highly crystalline monodisperse ETS-10 crystals with the length along the [110] direction (L<SUB>[110]</SUB>) between 17 and 55μm and the length along the [001] direction between 15 and 80μm were developed. This was achieved by varying the amounts of KF in the gel consisting of Na<SUB>2</SUB>SiO<SUB>3</SUB>, titanium isopropoxide, HCl, NaCl, KF, and H<SUB>2</SUB>O. The UV-vis spectra of the ETS-10 crystals revealed that the absorption band red-shifts with increasing L<SUB>[110]</SUB>. The plot of band gap energies (E<SUB>g</SUB> values) with respect to L<SUB>[110]</SUB> values revealed a progressively decaying relationship. The mixing of the newly observed data set with that reported previously from the ETS-10 crystals with L<SUB>[110]</SUB> between 0.3 and 20μm gave a smooth exponential decay relationship, E<SUB>g</SUB>=0.2578 exp(-L<SUB>[110]</SUB>/13.751)+3.7667, as if they came from a single data set. Analysis shows that the quantum confinement effect still operates in TiO<SUB>3</SUB><SUP>2-</SUP> quantum wires with the estimated length of 368nm. The μ<SUB>xy</SUB> and μ<SUB>z</SUB> values are 15.2 and 0.0006m<SUB>e</SUB>, respectively. A monotonous quadratic relationship exists between L<SUB>[110]</SUB> and l. Thus the length of the titanate quantum wire increases more than the degree the crystal size increases, indicating that the degree of defect per unit volume decreases as the crystal size increases.

Dynamic buckling analysis of a composite stiffened cylindrical shell

S.N. Patel,C. Bisagni,P.K. Datta 국제구조공학회 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.37 No.5

The paper investigates the dynamic buckling behaviour of a laminated composite stiffened cylindrical shell using the commercial finite element code ABAQUS. The numerical model of the composite shell is validated by static tests. In particular, the experimental collapse test is numerically simulated by a quasi static analysis carried out by both ABAQUS/Standard and ABAQUS/Explicit. The behaviour in the post-buckling field and the collapse load obtained by the analyses are close to the experimental data. The validated model is then used to study the dynamic buckling behaviour with ABAQUS/Explicit. The effects of the loading magnitude and of the loading duration are investigated, implementing in the analysis also first-ply failure criteria. It is observed that the dynamic buckling load is highly affected by the loading duration.

Parametric Resonance Characteristics of Laminated Composite Curved Shell Panels in a Hygrothermal Environment

S.K Sahu,M.K.Rath,P.K Datta,R. Sahoo 한국항공우주학회 2012 International Journal of Aeronautical and Space Sc Vol.13 No.3

The present study deals with the parametric resonance behaviour of laminated composite curved shell panels in a hygrothermal environment using Bolotin’s approach. A simple laminated model is developed using first order shear deformation theory (FSDT) for the vibration and dynamic stability analysis of laminated composite shells subjected to hygrothermal conditions. A computer program based on the finite element method (FEM) in a MATLAB environment is developed to perform all necessary computations. Quantitative results are presented to show the effects of curvature, ply-orientations, degree of orthotropy and geometry of laminates on the parametric instability of composite curved shell panels for different temperature and moisture concentrations. The excitation frequencies of laminated composite panels decrease with the increase of temperature and moisture due to reduction of stiffness for all laminates.