Overlapping with Jack Dunitz

The starting point was an overlap with Jack Dunitz in studies on the preferred conformation of the carboxyl group in saturated and unsaturated acids, esters and amides, orientational disorder of the hydrogen-bonded carboxylic acid dimer in benzoic acid crystal structures, and intramolecular lone pair-lone pair repulsion between oxygen atoms. The journey described here outlines a search to establish the existence of C−H⋅⋅⋅O hydrogen bonds and engineering cocrystals that incorporate intermolecular lone pair-lone pair repulsion between oxygen atoms.     

Integrated optimisation on flow-shop production with cutting stock

This paper addresses the integrated scheduling optimisation on flow-shop production with one-dimensional cutting stock in make-to-order environments. The upstream cutting-stock process provides the items for the downstream production, while the flow-shop production can be executed only when the required items are released. The efficient schedules on cutting plan and the production sequence should be determined in a coordinated manner to improve the overall efficiency. This study aims to find an integrated schedule to minimise the makespan of the entire manufacturing process. We develop a hybrid algorithm by integrating a local search method and some efficient strategies under the nested partitions framework. Numerical experiments show that the proposed approach is capable of achieving high-quality solutions within a reasonable time.     

Book review

The goal of this study is to extend Rasmussen's framework for risk management to research organisations having to deal with reduced income from government funding and increased market orientation. One human factors research organisation was studied in detail. Using archival records, changes were studied over the period 1989–2010. The results showed an increase in income from market funding relative to government funding, and a decrease in written output. Predictions by stress–strain theory were confirmed in that during the first 5 years of the period under consideration, a linear relationship between the increase in market funding and written output was observed, whereas a nonlinear relationship was observed in the next 5–10 years, indicating a larger decrease in written output than would be expected. Generally, the results show that research organisations are adaptive systems that trade off resource allocation to either commercial activities or scientific activities, depending on incentive schemes.     

A note on “A heuristic method for two-stage hybrid flow shop with dedicated machines”

In a recent paper by Wang and Liu (A heuristic for two-stage hybrid flow shop with dedicated machines. Computers & Operations Research 2013;40:438–50), two elimination rules are proposed for the hybrid flow shop with dedicated machines. This note shows that one of them is not valid and that the other is dominated by an other elimination rule.     

Can the revolution be optimised? Oh yes it can! But,maybe not. Report on the one day symposium on “Varieties of Enactivism”

The “Varieties of Enactivism: A Conceptual Geography” 4th April 2014, was a one day symposium which took place at Goldsmith University, London. The symposium had the explicit aim of clarifying the status of enactive cognitive science both as a unified paradigm for cognitive science and in relation to the broader embodied cognition framework. In what follows I offer a brief summery of the various talks followed by some thoughts on the current state of play within enactivism.     

Path-relinking Tabu search for the multi-objective flexible job shop scheduling problem

The multi-objective flexible job shop scheduling problem is solved using a novel path-relinking algorithm based on the state-of-the-art Tabu search algorithm with back-jump tracking. A routing solution is identified by problem-specific neighborhood search, and is then further refined by the Tabu search algorithm with back-jump tracking for a sequencing decision. The resultant solution is used to maintain the medium-term memory where the best solutions are stored. A path-relinking heuristics is designed to generate diverse solutions in the most promising areas. An improved version of the algorithm is then developed by incorporating an effective dimension-oriented intensification search to find solutions that are located near extreme solutions. The proposed algorithms are tested on benchmark instances and its experimental performance is compared with that of algorithms in the literature. Comparison results show that the proposed algorithms are competitive in terms of its computation performance and solution quality.     

Morphology formation in polypropylene impact copolymers under static melt conditions: A simulation study

In this article, the equilibrium morphology of a typical polypropylene (PP) impact copolymer (ICP) system is investigated by numerical self-consistent field simulations. The ICP was fractionated using temperature rising elution fractionation (TREF) to obtain the data necessary to define the simulation parameters. The results demonstrated the formation of a stratified droplet structure, in which ethylene content decreases from the center of the droplet toward the PP interface. This structure is shown to be in accordance with observations from transmission electron microscopy, scanning electron microscopy, and atomic force microscopy. The components are confined to a narrow layer whose position is primarily determined by its ethylene content. Leakage into a neighboring layer occurs to a degree that is determined by the component molecular weight and the difference in ethylene content between the layers. Simulations for a range of droplet sizes enable calculation of the interfacial tension. A typical drawback of TREF involves the inability to fractionate the amorphous part, leading to a large difference in ethylene content between the matrix and its neighboring layers. Although this effect is shown not to have a significant influence on the stratified structure, it is shown to have a significant influence on the derived interfacial tension. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

A grasp algorithm for m-machine flowshop scheduling problem with bicriteria of makespan and maximum tardiness

In this paper we address the problem of minimizing the weighted sum of makespan and maximum tardiness in an m-machine flow shop environment. This is a NP-hard problem in the strong sense. An attempt has been made to solve this problem using a metaheuristic called Greedy Randomized Adaptive Search Procedure (GRASP). GRASP is a competitive algorithm and is a meta-heuristic for solving combinatorial optimization problems. We have customized the basic concepts of GRASP algorithm to solve a bicriteria flow shop problem and a new algorithm named B-GRASP (Bicriteria GRASP algorithm) is proposed. The new proposed algorithm is evaluated using benchmark problems taken from Taillard and compared with the existing simulated annealing based heuristic developed by Chakravarthy and Rajendran. Computational experiments indicate that the proposed algorithm is much better than the existing one in all cases.     

Match-up approaches to a dynamic rescheduling problem

This article considers the problem of inserting arriving jobs into an existing schedule of a real world manufacturer. A number of match-up strategies, which collect the idle time on machines of a current schedule for the insertion of new jobs, are proposed. Their aim is to obtain new schedules with a good performance which are at the same time highly stable, meaning that they resemble as closely as possible the initial schedule. Basic rescheduling strategies such as ‘total rescheduling’, ‘right shift’ and ‘insertion in the end’ deliver either good performance or stability, but not both. Contrarily, our experimentation and statistical analysis reveal that the proposed match-up strategies deliver high performing schedules with a high stability. An analysis of the problem parameters that determine the behaviour of the proposed match-up algorithms is included in this article.     

Microstructure and sliding wear behavior of pseudo-alloy PS45/CuAl8 composite coating sprayed by HVAA technique

A pseudo-alloy PS45/CuAl8 composite coating was sprayed on steel substrate by high-velocity activated arc spraying (HVAA) process. Its sliding wear behavior at room temperature was evaluated by M-2000 wear tester. For comparison, a single CuAl8 coating was also prepared and tested under the same conditions. It is found that the pseudo-alloy composite coating consists of α-Cu and γ-Ni metallic matrix phases together with homogenously distributed minor Al 2 O 3 , Cr 2 O 3 oxide phases. Moreover, pseudo-alloy coating possesses much better sliding wear resistance than CuAl8 coating due to the enhanced hardness and microstructural homogenization. Fatigue wear and abrasive wear are responsible for the wear-down mechanism of the pseudo-alloy coating.