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Purpose The purpose of this paper is to investigate the impact of organizational size on adoption of green supply chain management (GSCM) practices for the Indian industry. It also evaluates the impact of GSCM practices on organizational performance. Design/methodology/approach This study aims to empirically test the GSCM model to investigate the present orientation of the Indian industry toward GSCM practices using a pre-tested structured questionnaire. The statistical inferences were drawn using the data provided by 161 Indian firms. This has compared the GSCM practice implementations among small-sized, medium-sized and large-sized organizations. Findings The study reveals that Indian organizations have shown a satisfactory implementation of majority of the environmental practices, except supplier ISO:14001 certification and Tier-II supplier evaluation. Out of 21 practices, medium-sized organizations have adopted GSCM practices at a similar level compared with large organizations, with three exceptions: existing environmental management systems, support from mid-level and top management and supplier evaluation for environmental practice. It was found that GSCM adoption can lead to equal improvements in operational performance for both large-size and medium-size organizations. Originality/value This paper makes two major contributions in the domain of green supply chain practices in India. First, it investigates the adoption of GSCM practices in organizations of different sizes (small, medium and large) and the impact of GSCM practices on the performance of organizations of different sizes. Second, it identifies the key areas for improvement and recommends a set of measures for improving the implementation of GSCM practices in Indian organizations.

We exploit the versatility provided by metal-dielectric composites to demonstrate controllable coherent perfect absorption (CPA) or anti-lasing in a slab of heterogeneous medium. The slab is illuminated by coherent light from both sides, at the same angle of incidence and the conditions required for CPA are investigated as a function of the different system parameters. Our calculations clearly elucidate the role of absorption as a necessary prerequisite for CPA. We further demonstrate the controllability of the CPA frequency to the extent of having the same at two distinct frequencies even in presence of dispersion, rendering the realization of anti-lasers more flexible.

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We derive general reciprocity relations that are applicable to a large class of one-dimensional stratified systems. These results reveal clearly the role of absorption and spatial symmetry in the nonreciprocity of reflection observed in a recent experiment by Armitage et al. [Phys. Rev. B 58, 15, 376 (1998)]. We also present examples of structures for which such nonreciprocal effects can be significant.

The formation of White (WEL) and Brown Etching Layers (BEL) on rail raceways during service causes the initiation of microcracks which finally leads to failure. Detailed characterization of the WEL and the BEL in a pearlitic rail steel is carried out from micrometer to atomic scale to understand their microstructural evolution. A microstructural gradient is observed along the rail depth including martensite, austenite and partially dissolved parent cementite in the WEL and tempered martensite, ultrafine/nanocrystalline martensite/austenite, carbon saturated ferrite and partially dissolved parent cementite in the BEL. Plastic deformation in combination with a temperature rise during wheel-rail contact was found to be responsible for the initial formation and further microstructural evolution of these layers. The presence of austenite in the WEL/BEL proves experimentally that temperatures rise into the austenite range during wheel-rail contact. This is in agreement with finite element modelling results. Each wheel-rail contact must be considered as an individual short but intense deformation and heat treatment cycle that cumulatively forms the final microstructure, as shown by diffusion length calculations of C and Mn. The presence of secondary carbides in the BEL indicates that the temperature in the BEL during individual loading cycles reaches levels where martensite tempering occurs. Partially fragmented primary cementite laths, enriched in Mn, depleted in Si, and surrounded by a C-gradient and dislocations were found in the BEL. The initial step in the formation of BEL and WEL is the defect-and diffusion-assisted decomposition of the original microstructure.