Jitendra Madaan

Development and characterization of PLA-based green composites: A review

With increasing environmental awareness and ecological risk, green composites have gained more and more research attention, as they have the potential to be attractive than the traditional petroleum-based composites which are toxic and nonbiodegradable. Because of their lightweight, friendly processing and acoustic insulation, green composites have been used widely ranging from aerospace sector to household applications. The end-of-life concern with many polymeric composites has also limited their application spectrum. The green composites not only replace the traditional materials such as steel and wood but also challenge certain nonbiodegradable polymer composites. The present research initiative aims at highlighting the issues and challenges in the development and characterization of poly lactic acid–based green composites. A few of these important composites and their mechanical properties (tensile, compressive, flexural, and impact strength) have been reported in this study. The focus is the identification of the possible areas for their novel applications. A study has been conducted to categorize the various types of green composites on the basis of their physical, chemical, and mechanical characteristics.

Comparative studies of mechanical and morphological properties of polylactic acid and polypropylene based natural fiber composites

In this study, natural fiber reinforced polylactic acid composites have been developed by hot pressing through film-stacking procedure. The reinforcement materials used are nettle, Grewia optiva and sisal fibers in the plain weave form. For comparison purposes, polypropylene-based composites using the same fibers have also been developed. Mechanical properties (tensile, compressive, flexural, and impact properties) of all the developed composites have been evaluated through standard test procedures. It has been found that the polylactic acid based composites have superior mechanical properties and can be a potential substitute for traditional synthetic fiber composites in many application areas. Polylactic acid/sisal composite showed overall the best performance in terms of mechanical behavior. The morphological study of the fractured surface during mechanical testing has been done using scanning electron microscopy, which provides the mechanism of failure of composites during different types of mechanical loadings.

Inventory management of perishable products: a time decay linked logistic approach

This paper proposes a logistic-based approach to a class of inventory problems with shortages and time decay functions. Time decay and shortages are a common phenomena in products with short life cycles, and financial volatility necessitates more accurate characterisation of inventory costs based on time-adjusted value. In this paper an extended approach of Wagner–Whitin (WW) is used to determine lot sizes, replenishment cycle, and schedules. A sensitivity analysis of the proposed optimisation procedure has been conducted to justify its advantages.

Decision and information interoperability for improving performance of product recovery systems

Enterprises around the world are employing product/resource recovery practices to overcome global competition, meet heightened environmental regulations, and seek additional profit making opportunities. These factors in addition to the inherent cost and complexity of recovery processes are due to multidimensional factors and relationships associated with the quality, variety, timeliness, demand changes, and logical processing of product returns. A Reverse Enterprise System (RES) perspective will give scope to develop a flexible system that can handle products with various options and greater return volumes and variability. It explores the various recovery functions and product lifecycle stages and suggests some key business and performance measurement strategies that can be employed to be successful in returns handling. We observed that different recovery nodes act in a relatively autonomous fashion to decide what type and level of flexibility to use, what and when the information is required to be shared for improving decision performance and obtaining benefits from the recovery process. Finally, this paper proposes a semi/partially and fully flexible decision model that facilitates decision and information interoperability functions from the perspective of an enterprise engaged in or planning to be engaged in product recovery processes.

Frictional and adhesive wear performance of natural fibre reinforced polypropylene composites

The potential of natural fibre reinforcement in the thermoplastic polymer matrix is being explored for enhancing the wear performance of neat polymer. In this study, sliding wear and frictional characteristics of natural fibre reinforced polypropylene thermoplastic composites are being investigated. Three types of natural fibres namely nettle, grewia optiva and sisal fibres have been used in mat form. The composites have been developed using compression moulding method through film stacking. The dry sliding wear test of developed composites is being performed against a steel counterface using pin-on-disc test apparatus under dry sliding condition. The tests have been conducted at different sliding speeds (1–3u2009m/s), applied loads (10–30u2009N) and sliding distances (1000–3000u2009m). Results show that incorporation of different natural fibre mats to polypropylene has improved the wear resistance of neat polymer. Scanning electron microscopic observations show different wear mechanisms such as debonding, cracks, fibre fracture and debris formation.

Flexibility Focused Decision and Information Sharing Model for Product Recovery System

As a result of rapid progress in technology and the shrinking product lifecycles faster than ever before, has led creeping realization of additional profits by performing the effective and efficient product recovery operations at a world-class level quintessential. Realization of these motives is complex due to the multidimensional relationships associated with the quality, variety, timeliness, demand changes, and logical processing of product returns and inherent complexity of recovery process. Therefore an Enterprise System (ES) perspective will give us a scope to develop a profit oriented recovery process as a flexible system that can handle products with various options and greater return volume and structural variability. This paper proposes generic model to enterprises engaged in or to be engaged in product recovery processes. A semi or partially flexible decision process model that facilitates flexible decision and information sharing (DIS) functions in product returns. This DIS model leads us to conceptualize the evolution of information associated with a product returns and how it might be encapsulated by Reverse Enterprise System (RES) to improve its profit and system performance.

Microwave Joining of Natural Fiber Reinforced Green Composites

Natural fiber based bio-composites are gaining prime importance these days because of their high strength to weight ratio and environmental benefits. An increase in the application spectrum of these materials necessitates cost effective high quality processing in order to meet the stringent design requirements. In the present investigation, fully biodegradable natural fiber (grewia optiva) reinforced poly lactic acid (PLA) composite has been developed. The tensile strength of the composite has been found to increase by 75% of that of the neat polymer. The developed composites have been joined using the adhesive bonding and the microwave joining. The tensile shear strength of the joint has been experimentally evaluated and it has been found that the bond strength of adhesively bonded specimen (4.9% of the parent material strength) is substantially lower as compared to microwave joined specimen (62.85% of the parent material strength). The process of microwave joining has also been simulated using standard Multiphysics software and the results were in close agreement with the experimentally recorded values.

Finite element model for microwave heating of thermoplastic composites

An increase in the application spectrum of polymeric composite materials necessitates cost effective high quality rapid processing in order to meet the stringent design as well as market requirements. Microwaves have been used for many years for kitchen and industrial heating applications. As, these heat materials volumetrically therefore reduces processing times and saves energy. The research work is progressing on the application of microwave energy for joining of thermoplastic-based materials. The present research investigation aims at proposing a finite element-based approach for studying the microwave heating process in context of thermoplastic composites. The preliminary model of the microwave heating has been highlighted and the related issues and challenges have been addressed. The initial findings from the finite element model suggest that microwave energy is a feasible and rapid solution for heating of thermoplastic composites leading to their joining.