Oscillatory structure–property correlation in azelate polyols and thermoplastic polyurethanes

Azelate polyols of 2000 g mol^?1 have been successfully prepared via esterification of renewable azelaic acid with linear diols containing different number of CH₂ repeating units. Structure–property correlation of the azelate polyols had been evaluated in thermoplastic polyurethanes (TPUs). TPUs based on azelate polyols of longer chained linear diols with >4 CH₂ repeat units retained higher degrees of crystallinity associated with the polyol soft segment. The ratio of hydrogen bonded urethane in the hard segment to free urethane phase mixed with the soft segment in the TPUs showed a complex oscillating dependence with increased number of CH₂ repeating unit in the linear diols of azelate polyols. Correspondingly, static and dynamic properties of TPUs also showed the oscillatory dependence, whereby dynamic properties maximized with odd number of CH₂ repeating unit and material strength maximized with even number of CH₂ repeating unit. The results therefore can be used as guide to select appropriate azelate polyols to target specific TPU performance. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46258.     

VNS methods for home care routing and scheduling problem with temporal dependencies,and multiple structures and specialties

The need for optimization in the Home Care Service is becoming more and more legitimate in the face of the increase of demand and cost all over the world. Recently, many researchers in the Operation Research community have been attracted by this issue, which presents interesting aspects related to the vehicle routing problems. In this paper, we consider a new variant called the vehicle routing problem with time windows, temporal dependencies (synchronization, precedence, and disjunction), multi‐structures, and multispecialties problem (VRPTW‐TD‐2MS). This new variant is an extension of the vehicle routing problems with time windows and synchronization constraints (VRPTW‐S) that is well‐studied in literature. We present a Mixed Integer Programming method, and propose three Variable Neighborhood Search approaches. Extensive experiments show the effectiveness and efficiency of the General Variable Neighborhood Search with Ejection Chains‐based local search for solving VRPTW‐TD‐2MS and VRPTW‐S.     

A New PSO-based Algorithm for Two-Dimensional Non-Guillotine Non-Oriented Cutting Stock Problem

In this paper, a new algorithm is proposed for the two-dimensional non-guillotine non-oriented cutting stock problem. The considered problem consists of cutting small rectangular pieces of predetermined sizes from large but finite rectangular plates. The objective is to generate cutting patterns that minimize the unused area and fulfill customer orders. The proposed algorithm is a combination of a new particle swarm optimization approach with a heuristic criterion inspired from the literature. The algorithm is tested on twenty-two instances divided into two sets. Corresponding results show the algorithm efficiency in optimizing the trim loss that is comprised between 2.6% and 7.8% for all considered instances.     

A case study and troubleshooting experience of safety power channel of instrumentation and control system of the BAEC TRIGA Research Reactor

Microsystem Technologies - Bangladesh Atomic Energy Commission TRIGA Research Reactor (BTRR) is a MK II type nuclear research reactor with a maximum thermal output power of 3 MW. Nuclear...     

Adaptive noise-reducing anisotropic diffusion filter

In image processing and computer vision, the denoising process is an important step before several processing tasks. This paper presents a new adaptive noise-reducing anisotropic diffusion (ANRAD) method to improve the image quality, which can be considered as a modified version of a speckle-reducing anisotropic diffusion (SRAD) filter. The SRAD works very well for monochrome images with speckle noise. However, in the case of images corrupted with other types of noise, it cannot provide optimal image quality due to the inaccurate noise model. The ANRAD method introduces an automatic RGB noise model estimator in a partial differential equation system similar to the SRAD diffusion, which estimates at each iteration an upper bound of the real noise level function by fitting a lower envelope to the standard deviations of pre-segment image variances. Compared to the conventional SRAD filter, the proposed filter has the advantage of being adapted to the color noise produced by today’s CCD digital camera. The simulation results show that the ANRAD filter can reduce the noise while preserving image edges and fine details very well. Also, it is favorably compared to the fast non-local means filter, showing an improvement in the quality of the restored image. A quantitative comparison measure is given by the parameters like the mean structural similarity index and the peak signal-to-noise ratio.     

Evaluation of effect of blast design parameters on flyrock using artificial neural networks

Flyrock, the propelled rock fragments beyond a specific limit, can be considered as one of the most crucial and hazardous events in the open pit blasting operations. Involvement of various effective parameters has made the problem so complicated, and the available empirical methods are not proficient to predict the flyrock. To achieve more accurate results, employment of new approaches, such as artificial neural network (ANN) can be very helpful. In this paper, an attempt has been made to apply the ANN method to predict the flyrock in the blasting operations of Sungun copper mine, Iran. Number of ANN models was tried using various permutation and combinations, and it was observed that a model trained with back-propagation algorithm having 9-5-2-1 architecture is the best optimum. Flyrock were also computed from various available empirical models suggested by Lundborg. Statistical modeling has also been done to compare the prediction capability of ANN over other methods. Comparison of the results showed absolute superiority of the ANN modeling over the empirical as well as statistical models. Sensitivity analysis was also performed to identify the most influential inputs on the output results. It was observed that powder factor, hole diameter, stemming and charge per delay are the most effective parameters on the flyrock.     

Deactivation behavior of ruthenium promoted Co/γ-Al2O3 catalysts in Fischer–Tropsch synthesis

Heterogeneous catalytic hydrogenation of cyclohexene, catalyzed by Pt/Al₂O₃, was carried out in solutions of 2-hydroxyethylammonium formate (a room temperature ionic liquid, RTIL) mixed with methanol, ethanol and propan-2-ol at 25 °C. The rate constants of the reaction in ionic liquid alcohol mixtures were higher than alcohol alone. First-order rate constant of the reaction in the RTIL relative to propan-2-ol is approximately 28. Furthermore, the rate constant of the reaction increases with the mole fraction of the ionic liquid. Single-parameter correlations of log k vs. normalized polarity parameter (), hydrogen-bond acceptor basicity (β) and hydrogen-bond donor acidity () do not give acceptable results in the solutions. In addition, log k does not show an acceptable dual-parameter correlation with π* (dipolarity/polarizibility, one of the Kamlet–Taft parameters for solvent that shows the dipolarity of the solvent) and , π* and β and and β. However single-parameter correlation of log k vs. π^* gives reasonable results. The increase of the reaction rate with π^* is attributed to the non-polar nature of the reactants.