A neural network job-shop scheduler

This paper focuses on the development of a neural network (NN) scheduler for scheduling job-shops. In this hybrid intelligent system, genetic algorithms (GA) are used to generate optimal schedules to a known benchmark problem. In each optimal solution, every individually scheduled operation of a job is treated as a decision which contains knowledge. Each decision is modeled as a function of a set of job characteristics (e.g., processing time), which are divided into classes using domain knowledge from common dispatching rules (e.g., shortest processing time). A NN is used to capture the predictive knowledge regarding the assignment of operation’s position in a sequence. The trained NN could successfully replicate the performance of the GA on the benchmark problem. The developed NN scheduler was then tested against the GA, Attribute-Oriented Induction data mining methodology and common dispatching rules on a test set of randomly generated problems. The better performance of the NN scheduler on the test problem set compared to other methods proves the feasibility of NN-based scheduling. The scalability of the NN scheduler on larger problem sizes was also found to be satisfactory in replicating the performance of the GA.     

Fast ion transport in the new mixed system (CuI)x·[(Ag2O)2·(V2O5)]100−x (40≤x≤80)

The new mixed system (Cul) _x ·[(Ag₂O)₂·V₂O₅)]_100–x where x=40, 45, 50, 55, 60, 65, 70, 75 and 80 mol% was investigated as a possible glassy fast ion conductor by preparing molten mixtures and quenching them to low temperatures. The analysis of their composition was carried out using differential scanning calorimetry (DSC) and powder X-ray diffraction (XRD) techniques. These studies have confirmed the formation of new substances. Formation of AgI in some samples was also revealed by XRD analysis and by the occurrence of a characteristic phase transition temperature around 420 K identified through DSC experiments as well. Detailed temperature-dependent a.c. electrical conductivity studies were carried out on the new materials by a.c. impedance analysis in the frequency range 65.5 kHz-1 Hz and over the temperature range 293 to 398 K. It has been found that the highest electrical conductivity of 3.64×10^–3 S cm^–1 at 305 K due to the migration of Ag⁺ ions and the lowest activation energy of 0.1 eV in the above temperature range of investigation could be realized for the composition 40CuI-40Ag₂O-20V₂O₅ in the mixed system.     

Pressure-induced shifts of the fluorescence spectrum of rhodamine 6G in solution

The effect of hydrostatic pressure on the fluorescence spectrum of rhodamine 6G dye in two different solutions is studied. The peak shifts to longer wavelengths with increasing pressure with a pressure coefficient of -29 and -19 cm(-1)/kbar for ethanol and 4:1 methanol-ethanol solvents, respectively. Possible applications of increasing the tunability of dye lasers by pressure are discussed.     

Determination of the complex permittivity of packaging materials at millimeter-wave frequencies

The focus of this paper is the determination of the complex permittivity of chip packaging materials at millimeter-wave frequencies. After a broad overview of existing measurement techniques, three methods will be presented that have been established for the dielectric property determination of substrate, as well as mold materials (encapsulants, under-fill, etc.) in the millimeter-wave frequency range. First, the open resonator used here will be briefly described. It allows accurate determination of the dielectric constant and loss of thin sheet substrate materials from below 20 GHz to above 100 GHz. Second, a filled waveguide method is explained in detail. The setup used here can determine the complex dielectric properties of mold materials from 70 to 100 GHz. Third, the method based on covered transmission lines will be described in detail. The used lines allow measurements from below 40 GHz to approximately 90 GHz. Verification of all three methods will be provided by inter-comparison and comparison to values from the literature. Additionally, results for several typical substrate and mold materials that are available for millimeter-wave packaging will be shown and discussed.     

Stable imposition of stiff constraints in explicit dynamics for embedded finite element methods

We investigate various strategies to enforce the kinematics at an embedded interface for transient problems within the extended finite element method. In particular, we focus on explicit time integration of the semi‐discrete equations of motion and extend both dual and primal variational frameworks for constraint enforcement to a transient regime. We reiterate the incompatibility of the dual formulation with purely explicit time integration and the severe restrictions placed by the Courant–Friedrichs–Levy condition on primal formulations. We propose an alternate, consistent formulation for the primal method and derive an estimate for the stabilization parameter, which is more amenable in an explicit dynamics framework. Importantly, the use of the new estimate circumvents the need for any tolerances as an interface approaches an element boundary. We also show that with interfacial constraints, existing mass lumping schemes can lead to prohibitively small critical time steps. Accordingly, we propose a mass lumping procedure, which provides a more favorable estimate. These techniques are then demonstrated on several benchmark numerical examples, where we compare and contrast the accuracy of the primal methods against the dual methods in enforcing the constraints. Copyright © 2012 John Wiley & Sons, Ltd.     

Extraction of anthocyanins from red cabbage and purification using adsorption

There is an increasing interest in anthocyanins, as natural food colorants, in food products and also in pharmaceutical products due to their antioxidative potential. The present study deals with extraction and purification of anthocyanins from red cabbage. Conventional extraction methods of anthocyanin from plant material are non-selective and yield pigment solutions with large amounts of byproducts such as sugars, organic acids and proteins. Some of these impurities may accelerate anthocyanin degradation. Different extracting media were used and the mixture of 50% (v/v) ethanol and acidified water resulted in maximum anthocyanin content (390.6 mg/L). In order to obtain anthocyanins in a purified form, adsorption was carried out with six different adsorbents. Among these, non-ionic acrylic ester adsorbent, namely Amberlite XAD-7HP, showed the highest adsorption capacity (0.84 mg/mL of resin) and desorption ratio (92.85%). Adsorption results were found to be correlated best using the Langmuir isotherm equation especially at low temperature. The resulting anthocyanin solution after purification was free from sugars, which are the major cause for degradation of anthocyanin. No browning was observed and chroma increased by 27% compared to crude anthocyanin.     

Matched‐dual‐polymer electrochromic lenses,using new cathodically coloring conducting polymers,with exceptional performance and incorporated into automated sunglasses

Reported are syntheses of several new monomer precursors of cathodically coloring conducting polymers (CPs), based on a propylene dioxythiophene skeleton. These are shown to yield CPs—both as homopolymers and as copolymers—that are nearly “perfectly” matched electrochemically and electrochromically with a set of anodically coloring poly(aromatic amines), for use in dual‐polymer electrochromic lenses. Resulting dual‐polymer electrochromic lenses display very high light/dark contrast (typically up to 70/7% or 50/0.5% Transmission (integrated over visible spectrum, vs. air reference), Haze < 2%, very high cyclability (> 10 K cycles), multiyear shelf life, appealing transparent to dark‐blue‐black transition, and excellent optical memory. Dramatic lowering of switching time, from 8 to < 1 s, is demonstrated using unique applied‐potential algorithm resident on inexpensive Microcontroller chip. Working, practical dual‐polymer electrochromic spectacles are demonstrated with electrochromic lenses retrofitted to spectacles meeting ANSI Z87.1, GL‐PD 10–12 (U.S. military) specifications. These incorporate photosensor, rechargeable Li battery, Microcontroller, allow for automated operation. Ab‐initio‐design spectacles, also conforming to above specifications, are also demonstrated, with components seamlessly hidden within frame. To the best of our knowledge, the electrochromic lenses and sunglasses reported herein represent the best visible‐region electrochromic performance for dual‐polymer CP electrochromic systems to date and the first practical implementation in working sunglasses. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41043.     

Evaluation of hydroxyapatite and β-tri calcium phosphate microplasma spray coated pin intra-medullary for bone repair in a rabbit model

Here we report a comparative study of the healing kinetics of surgically created artificial defects in the tibia of New Zealand white rabbits. Comparison of the healing kinetics was made for uncoated conventional SS316L intramedullary pins, and the same pins with microplasma sprayed (MIPS) pure hydroxyapatite (HAp) and beta-tri calcium phosphate (β-TCP) coatings. After thorough material characterizations including XRD, FTIR, SEM, etc., MIPS coated pins were implanted to such animals. Serum biochemistry, radiology and fluorochrome labelling were used to evaluate the comparative healing kinetics of these implants in vivo. In comparison to those of the uncoated pins, the pins coated with both MIPS HAp and β-TCP showed significant increment of alkaline phosphatase up to 15th postoperative day, insignificant changes in serum phosphorus and calcium with uneventful healing of bone defect. There was development of Havarsian canals and well-defined peripherally placed osteoblasts along with evidence of angiogenesis and comparatively more new bone formation in the defect site. On a comparative scale, the performance of the β-TCP coated intramedullary pins was much better than that of the pure HAp coated pins than the uncoated intramedullary pins.     

Optimization of Welding Process Parameters for 9Cr-1Mo Steel Using RSM and GA

Optimization of A-TIG welding process parameters for 9Cr-1Mo steel has been carried out using response surface methodology (RSM) and genetic algorithm (GA). RSM has been used to obtain the design matrix for generating data on the influence of process parameters on the response variables. A second-order response surface model was developed for predicting the response for the set of given input variables. Then, numerical and graphical optimization was performed using RSM to obtain the target depth of penetration (DOP) and heat-affected zone (HAZ) width using desirability approach. Multiple regression models were developed based on the generated data, and then the models were used in GA to determine the optimum process parameters for achieving the target DOP and HAZ width. GA-based models employed two different selection processes. Both the RSM- and GA-based models suggested a number of solutions in terms of process parameters, and the identified solutions were validated by experiments. GA-based model employing tournament selection has been found to be a more accurate method for determining the optimum A-TIG welding process parameters.