In the last 25 years, extensive research has been carried out addressing the flexible job shop scheduling (JSS) problem. A variety of techniques ranging from exact methods to hybrid techniques have been used in this research. The paper aims at presenting the development of flexible JSS and a consolidated survey of various techniques that have been employed since 1990 for problem resolution. The paper comprises evaluation of publications and research methods used in various research papers. Finally, conclusions are drawn based on performed survey results.

International audienceThree-dimensional (3D) short fatigue crack growth behaviour in a cast magnesium alloy, Elektron 21, was studied using a combination of X-ray diffraction contrast tomography (DCT) and microtomography at the European Synchrotron Radiation Facility. A 3D map of grain shapes and crystallographic orientations was produced in a miniature fatigue specimen using DCT. A focused ion beam instrument was used to introduce small notches in selected grains. Synchrotron microtomography was used to study the evolution of fatigue cracks from these notches during interrupted in situ fatigue cycling. Stage I crack growth occurred preferentially on the basal plane of the magnesium hexagonal close packed crystal, with local crack growth rates between 4 and 40 nm cycle 1. Retardations in the local crack growth rate were observed in certain grains and at certain grain boundaries. The observed interactions between the crack and the polycrystalline microstructure can be explained using Schmid factors and a development of the tilt-twist model of Zhai and Wilkinson (Zhai T, Wilkinson AJ, Martin JW. Acta Mater 2000;48;4917)

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Pyrethrins and flower yield of pyrethrum (Chrysanthemum cinerariaefolium Viz.) plants were determined after application of ethrel, chlormequat chloride and paclobutrazol. Ethrel at 50, 100, 250 and 500 mg l -l produced a significant positive effect on pyrethrins level, decreased plant height, while 50 and 100 mg l -l significantly increased fresh and dry flower yield. Chlormequat chloride at 1000 and 2000 mg l -l and paclobutrazol (80 and 160 mg l -l ) increased pyrethrins level, single flower weight and decreased plant height and flower yield. 14 C-acetate incorporation studies further substantiated positive effect of growth retardants on pyrethrins biosynthesis. The effect of growth retardants on pyrethrins seems to be mediated through its effect on biosynthesis.

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Purpose Analysis of relationship between energy and growth offers the sustainable energy pathway for a country’s sustainable economic development. This study aims to focus on the evaluation of the Pakistan’s energy system using long-run energy alternative planning (LEAP) modeling framework through different growth scenarios. Design/methodology/approach Principal component analysis has been adopted for indicators index formation. Study period of 1980 to 2030 is covered by forward and backward simulations in LEAP software. Findings The study reveals that current energy policy does not have the potential to lead the country toward a desired goal of economic sustainability. Research limitations/implications In falling off scenario, negative growth rate (-5 per cent) assumption is also debatable; LEAP shows an error in the analysis and takes the last positive available value for any further analysis as a default. This case could have been simply omitted from results but for research contribution, the computations for this case are also reported. Practical implications Long-range energy alternative planning model has been applied to answer the corresponding question for simulation period of 1980 to 2030 to better compare the past trend and future expectations. Critical analysis of four selected scenarios (BAU, moderate, advanced and falling off) indicate that energy policy of Pakistan is poorly managed to maintain energy system’s effectiveness. Social implications As far as statistical difference is concerned, early years have more fluctuation; however, from 2009, curve flattens for energy consumption and energy demand. The increasing demand of energy impacts the society and hence disturbs all sectors. Originality/value Policymakers have been so dragged off from the main route to sustainability, despite all odds there is a huge unexplored potential in the country for use to move in step with the world for a better tomorrow. The study educates the policymakers to comprehend the future energy scenarios and make rational decisions based on the study outcomes.

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