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An improved higher-order zigzag plate theory in a random environment is proposed and it is implemented in a stochastic finite element framework to study the buckling characteristic of sandwich plates with random material properties. The theory satisfies transverse shear stress continuity at all of the layer interfaces and the transverse shear-stress-free condition at the top and bottom surfaces. It also includes the effect of transverse deformability to the core. The through-thickness variation of in-plane displacements is assumed to be cubic, whereas transverse displacement varies quadratically within the core and it remains constant over the face sheets. Note that sandwich and composite structures are characterized by inherent uncertainties in their material properties. The effect of these uncertainties on the buckling characteristic of sandwich plates is studied by modeling the macromechanical material properties as basic random variables. A stochastic finite element method consisting of an efficient [C.sup.[theta]] finite element in conjunction with a mean-centered first-order perturbation approach is developed, and the model is employed to evaluate the second-order statistics of the buckling loads. The published results are used to validate the deterministic part of the proposed approach, and its stochastic component is validated with an independent Monte Carlo simulation.

Highlights • Advanced statistical tools like AMMI and GGE were used whose usage has not been found in eggplant so far. • Lal Kuli , Samrat , Mala , Muktamala , Lamba Kuli , Mukta Hasi , Muktazuri and Heera can be recommended for general cultivation. • Autumn-winter and spring-summer seasons are the two different mega-environments whose effect on yield is different. • Muktamala and Muktazuri were having high similarity percentage and their response to the seasonal changes was almost same. • Panna , Makra Midlong and KS-8103 were found to be diverse from others in their response to environment. Abstract The experiment was carried out in four consecutive seasons to study the phenotypic stability of eggplant germplasm for yield components and fruit quality parameters. The data were subjected to modern statistical tools like Additive Main effects and Multiplicative Interaction (AMMI) model and the Genotype main effects and Genotype × Environment Interaction effects (GGE) model and Cluster Analysis. The IPCA-I was attributed 58.53% and 80.36% Genotype × Environment (G × E) variation of fruit weight and fruit yield per plant, respectively. The cumulative contribution of IPCA-I and IPCA-II to the total G × E variance was 95.72% for number of fruits per plant, 91.02% for anthocyanin in peel, 87.0% for total phenols and 93.42% for DPPH Free Radical Scavenging Capacity (DPPHFRSC). Significant residual interaction values demonstrated the presence of a considerable noise for total phenols and DPPHFRSC. AMMI-I biplot indicated that Lal Kuli , Samrat , Mala , Muktamala , Lamba Kuli , Mukta Hasi , Muktazuri and Heera could be recommended for general cultivation in both spring-summer and autumn-winter to achieve optimum yields. The autumn-winter and spring-summer seasons were emerged as two different mega-environments. Cluster analysis revealed the high percentage of similarity between Muktamala and Muktazuri and the diverse nature of Panna, Makra Midlong and KS-8103 in terms of response to the environment. [ABSTRACT FROM AUTHOR]

A pre-impoundment study of biotic communities was conducted in the Kishanganga river in Jammu and Kashmir on which a hydro-electric project is proposed. The present study was carried out in two phases, monsoon and post-monsoon, at three sites for the physical, chemical and biological characteristics of the river. There were no significant differences between two phases in the physical and chemical characteristics of the river water except water current velocity and turbidity. Among the biological components, significant differences were observed in the density of phytoplankton and macro-invertebrates between the two phases. Higher densities of these communities were observed during second phase with the exception of one site. Phytobenthos showed only a slight difference in the density between two phases. Didymosphenia geminata (Lyngbye) M. Schmidt. was the most common and abundant species in the phytoplankton as well as phytobenthic communities during both the phases, whereas Leptoceridae and Baetidae were the most commonly represented taxa among macro-invertebrates. Our studies suggest that the river is unpolluted and supports a rich and diverse community composed of species that are mainly pollution intolerant. This study provides baseline data for the aquatic biodiversity of an unregulated Himalayan river and for preparation of an environment management plan for conserving the biotic communities of the river. [ABSTRACT FROM AUTHOR]

The reproductive biology of two subspecies of Coptis teeta was studied. The species is an endangered, herbaceous perennial, endemic to the Mishmi Hills in Eastern Himalaya. We investigated reproductive strategies of the subspecies, their breeding systems and reproductive output. They had contrasting reproductive strategies; ssp. teeta reproduces sexually and produces fewer ramets, while ssp. lohitensis propagates mostly vegetatively through a higher number of ramets. There is a resource adjustment between vegetative and sexual functions with a greater allocation to the former, particularly in ssp. lohitensis. Manual crosses showed that the species is self- and cross-compatible, but is essentially an autogamous selfer. Seed set in the species is generally low, with higher output in ssp. teeta and lower in ssp. lohitensis. The low fecundity is ascribed to a number of pre- and postfertilization events, including unsuitability of floral features for attracting pollinators, high pollen sterility and high rates of fruit and seed abortion. Sexual reproduction does not contribute significantly towards population increase in this species. This could be an important factor contributing to its rarity. © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 143 , 47-54. [ABSTRACT FROM AUTHOR]

We present a detailed design and characterization for a compact X-junction we proposed recently. Even at a wide full-branching angle of 1.4°, simulation predicts the crosstalk and insertion loss to be -20.1 and 0.2 dB, respectively; the wavelength bandwidth is 230 nm (1390-1620 nm). Devices made in polymer realize -16.1-dB crosstalk and 0.3-dB loss [ABSTRACT FROM PUBLISHER]

Spar Wingskin Joint (SWJ) comprises of a thin spar which overlaps and is co-cured to a thick wingskin by suitable adhesive materials. These joints are mostly used in integral modular fabrication of aircraft and fuselage wing structures usually made with curved laminated Fibre Reinforced Polymeric (FRP) composite panels. This paper deals with the analyses of initiation of adhesion failure and its propagation in SWJs subjected to transverse loadings using Finite Element Analyses (FEA) and fracture mechanics approach. Normal and shear stress distributions at different interfacial locations between the adherends and the adhesive have been evaluated. Tsai-Wu coupled stress failure criteria have been used to identify the location of onset of adhesion failure. The critical location for onset of adhesion failure has been found to be at the toe-end of the spar wingskin overlap region. Pre-embedded adhesion failure has been simulated at this location and Strain Energy Release Rate (SERR) components corresponding to Mode I, Mode II and Mode III of adhesion failure have been determined using the principle of Virtual Crack Closure Technique (VCCT). Rate of propagation of adhesion failure has been evaluated by sequential release of Multi-Point Constraint (MPC) and contact finite elements provided at the pre-embedded failure front. It has been observed that Mode I component of SERR primarily governs the process of adhesion failure propagation. The appropriate spar overlap length on the wingskin has been determined in order to prevent adhesion failure. Further, an attempt has been made to improve the structural integrity of the SWJ by reducing the stress concentration at the ends of spar and wingskin overlap. This has been achieved by obtaining a favourable stress distribution over the entire joint structure by using Functionally Graded Materials (FGM) in the spar and wingskin adherend instead of FRP composite panels. Exponential gradation indices have been used for material grading of the spar and wingskin adherends. It has been seen that peel and shear stresses and values of SERR components as well as total SERR reduce significantly by use of FGMs with suitable exponential material grading index. [ABSTRACT FROM AUTHOR]

3D Finite Element Analyses have been carried out for Spar Wingskin Joints made with laminated Graphite Fibre Reinforced Plastic composites subjected to uniformly distributed transverse load. The delamination has been pre-embedded at the most likely location, i.e. in resin layer between the top and next ply of the fibre reinforced plastic laminated wingskin and near the spar overlap end. Multi-Point Constraint finite elements have been made use of at the vicinity of the delamination fronts. This helps in simulating the growth of the embedded delamination at both ends. The inter-laminar peel and shear stresses responsible for causing delamination damage have been evaluated. Strain energy release rate components corresponding to the Mode I (opening), Mode II (sliding) and Mode III (tearing) of delamination are determined using the principle of Virtual Crack Closure Technique. These are seen to be different and non-self-similar at the two fronts of the embedded delamination. Mode I Strain energy release rate ( G I ) primarily governs the process of delamination propagation. [ABSTRACT FROM AUTHOR]

Cellular structures are light weight structures with high specific, impact, flexural strength and stiffness. Hierarchical structures offer higher load-bearing capacity compared to their conventional counter parts. In this study, performance of enhanced hierarchical honeycomb core cellular structures under compression and impact loads is investigated. The hierarchy is proposed by varying the order and the level of the cells. Hierarchical patterns are developed by replacing the vertex cells of regular hexagonal honeycomb with circular cells. The local arrangement of the proposed hierarchical cellular structures is improved to withstand higher loads. The out-of-plane performance of honeycomb structure is enhanced by a hierarchical scheme. As a result, a novel hierarchical second order second level hexagon based hybrid cell has been developed. Furthermore, the influence of sandwiching the cellular structures between face sheets against impact loads is also studied using numerical simulations. In order to transfer the loads efficiently from the top and bottom ends to the mid walls of the unit cell, the structural angle β is introduced as the angle between the normal of the face-sheet and the axis of the unit cell. Such an arrangement is observed to enhance the load distribution in the cellular structures. [ABSTRACT FROM AUTHOR]