Non-permutation flowshop scheduling with dual resources

Typically, in order to process jobs in a flowshop both machines and labor are required. However, in traditional scheduling problems, labor is assumed to be plentiful and only machine is considered to be a constraint. This assumption could be due to the lower cost of labor compared to machines or the complexity of dual-resource constrained problems. In this paper a mathematical model is developed to minimize the work-in-process inventory while maximizing the service level in a flowshop with dual resources. The model focuses on optimizing a non-permutation flowshop. There are different skill levels considered for labor and the setup times on machines are sequence-dependent. Jobs are allowed to skip one or more stages in the flowshop. Job release and machine availability times are considered to be dynamic. The problem is solved in two layers. The outer layer is a search algorithm to find the schedule of jobs on the machine (traditional flowshop scheduling problem) and the inner layer is a three-step heuristic to find a schedule of jobs on labor in accordance to the machine schedule. Three different search algorithms are developed to solve the proposed NP-hard problem. First algorithm can solve a permutation flowshop while the other two are developed to solve a non-permutation flowshop. The comparison between the optimal solution and the search algorithms in small examples shows a good performance of the algorithms with an average deviation of only 2.00%. An experimental design analyzes the effectiveness and efficiency of the algorithms statistically. The results show that non-permutation algorithms perform better than the permutation algorithm, although the former are less efficient. The effectiveness and efficiency in all three algorithms have an inverse relation. To the best of our knowledge, this research is the first of its kind to provide a comprehensive mathematical model for dual resource flowshop scheduling problem.     

RETRACTED ARTICLE: Induced-charge electrokinetic phenomena

The induced-charge electrokinetic (ICEK) phenomena are relatively new area of research in microfluidics and nanofluidics. Different from the traditional electrokinetic phenomena which are based on the interactions between applied electric field and the electrostatic charge, the ICEK phenomena result from the interaction of the applied electric field and the induced charge on polarisable surfaces. Because of the different underline physics, ICEK phenomena have many unique characteristics that may lead to new applications in microfluidics and nanofluidics. In this paper, we review the major advancement of research in the field of ICEK phenomena, discuss the applications and the limitations, and suggest some future research directions.     

Influence of Linker Length on Ligase-Catalyzed Oligonucleotide Polymerization

Ligase-catalyzed oligonucleotide polymerization (LOOPER) that enables the sequence-defined generation of DNA with up to 16 different modifications has recently been developed. This approach was used to develop new classes of diversely modified DNA aptamers for molecular recognition through in vitro evolution. The modifications in LOOPER are appended by use of a long hexane-1,6-diamine linker, which could negatively impact binding thermodynamics. Here we explore the incorporation of modifications with the aid of shorter linkers and the use of commercially available phosphoramidites and assess their efficiency and fidelity of incorporation. We observed that shorter linkers are less tolerated during LOOPER, with very short linkers providing high levels of error and sequence bias. An ethane-1,2-diamine linker was found to be optimal in terms of yield, efficiency, and bias; however, codon adjustment was necessary. This shorter-linker anticodon set for LOOPER should prove valuable in exploring the impact of diverse chemical modifications on the molecular function of DNA.     

Synthesis of single-walled carbon nanotubes by induction thermal plasma

The production of high quality single-walled carbon nanotubes (SWCNTs) on a bulk scale has been an issue of considerable interest. Recently, it has been demonstrated that high quality SWCNTs can be continuously synthesized on large scale by using induction thermal plasma technology. In this process, the high energy density of the thermal plasma is employed to generate dense vapor-phase precursors for the synthesis of SWCNTs. With the current reactor system, a carbon soot product which contains approximately 40 wt% of SWCNTs can be continuously synthesized at the high production rate of ∼100 g/h. In this article, our recent research efforts to achieve major advances in this technology are presented. Firstly, the processing parameters involved are examined systematically in order to evaluate their individual influences on the SWCNT synthesis. Based on these results, the appropriate operating conditions of the induction thermal plasma process for an effective synthesis of SWCNTs are discussed. A characterization study has also been performed on the SWCNTs produced under the optimum processing conditions. Finally, a mathematical model of the process currently under development is described. The model will help us to better understand the synthesis of SWCNTs in the induction plasma process.      

Preparation and Characterization of Long Chain Branched Polypropylene through UV Irradiation and Coagent Use

Trimethylolpropane triacrylate as coagent was utilized along with benzophenone to modify polypropylene by generating long chain branches in the polypropylene molecular structure. The effects of trimethylolpropane triacrylate concentration, benzophenone concentration, and irradiation duration on viscoelastic properties and gel content were studied. The processing conditions that result in the greatest amount of long chain branching with minimum amount of gel content were identified. Gel permeation chromatography was used to confirm formation of branches and determine the branching content, whereas Fourier transform infrared spectroscopy confirmed the contribution of trimethylolpropane triacrylate in the formation of long chain branches.     

Numerical study of temperature distribution in an inverse moving boundary problem using a meshless method

In this paper, we consider the inverse one-phase one-dimensional Stefan problem to study the thermal processes with phase change in a moving boundary problem and calculate the temperature distribution in the given domain, as well as approximate the temperature and the heat flux on a boundary of the region. For this problem, the location of the moving boundary and temperature distribution on this curve are available as the extra specifications. First, we use the Landau’s transformation to get a rectangular domain and then apply the Crank–Nicolson finite-difference scheme to discretize the time dimension and reduce the problem to a linear system of differential equations. Next, we employ the radial basis function collocation technique to approximate the spatial unknown function and its derivatives at each time level. Finally, the linear systems of algebraic equations constructed in this way are solved using the LU factorization method. To show the numerical convergence and stability of the proposed method, we solve two benchmark examples when the boundary data are exact or contaminated with additive noises.

     

A novel method to musicalize shape and visualize music and a novel technique in music cryptography

Since many years ago, musicians have composed music based on the images that they have had in their minds. On the other hand, music affects people’s imagination while hearing it. This research provides a method that can transform shape to music and music to shape. This method defines musical notations for horizontal, diagonal and vertical line segments, filled circle and curve with different colors, which are the basis of many shapes in transforming shapes into music. Then these primary mappings are generalized to more complex forms to transform any shape. Moreover, music can be transformed into shape by this method. For this transformation, primary musical notations such as simple notes, notes joined by a legato, notes with a staccato, notes joined by a legato and have crescendo or decrescendo and notes with an accent or a trill are defined. These primary musical notations are generalized to more complex forms to transform any music into shape. Also, the method of this research can be used in music cryptography. It employs mapping of notes in a twelve-tone equal musical system into shapes and mappings of shapes with an equal line width and different colors into music.