Optimization of Continuous Casting Using Simulation

This paper describes the development and use of an integrated system of metamodels and simulation experiments for managing quality in a continuous casting system. A systematic procedure was developed to satisfy the necessary process conditions connected to one or more process parameters. The values of these parameters are to be determined such that all the process conditions are satisfied simultaneously to ensure that the product will have the desired quality. This procedure utilizes a set of metamodels, simulation experiments, and an index called the “undesirability index” for quality, which establishes a functional relationship between the input variables or process parameters and the quality criteria. This system, when applied to the data pertaining to a case, demonstrated that the methodology developed could be used to effectively manage product quality.     

Multiobjective differential evolution (MODE) for optimization of adiabatic styrene reactor

In this paper, a novel algorithm is proposed for solving multiobjective optimization problems. The proposed algorithm, multiobjective differential evolution (MODE), is applied to optimize industrial adiabatic styrene reactor considering productivity, selectivity and yield as the main objectives. Five combinations of the objectives are considered. Pareto set (a set of equally good solutions) obtained for all the cases is compared with results reported using non-dominated sorting genetic algorithm (NSGA). The results show that all objectives besides profit can be improved compared to those reported using NSGA and current operating conditions. The Pareto optimal front provides wide-ranging optimal operating conditions and an appropriate operating point can be selected based on the requirements of the user.     

Classification of run-length encoded binary data

In classification of binary featured data, distance computation is carried out by considering each feature. We represent the given binary data as run-length encoded data. This would lead to a compact or compressed representation of data. Further, we propose an algorithm to directly compute the Manhattan distance between two such binary encoded patterns. We show that classification of data in such compressed form would improve the computation time by a factor of 5 on large handwritten data. The scheme is useful in large data clustering and classification which depend on distance measures.     

The influence of parameters of chemical synthesis on the optical properties of CdS nanocrystals

A systematic analysis is presented on the influence of parameters of synthesis on the formation and optical properties of CdS nanocrystals prepared using dimethyl formamide as solvent and stabilizing agent. The parameters considered are the molar ratios of cadmium to sulfur, initial concentration of Cd²⁺ and S²⁻ at a fixed molar ratio and atmospheric conditions. Optical absorption and photoluminescence measurements were carried out during the synthesis to monitor the changes in optical properties. The results clearly indicate that the nanocrystals size could be tuned by varying the molar ratio of the starting materials. Ambient conditions are found to play a vital role on the stability and optical properties of the nanocrystals whereas the concentration of the starting materials had little influence on the optical absorption and luminescence properties. These results are expected to help in developing a better understanding of the mechanisms of solution growth and size stabilization of semiconductor nanocrystals during chemical synthesis.     

Intergranular corrosion damage evaluation through laser scattering technique

AISI type 316 austenitic stainless steel in sensitized condition was subjected to ASTM A262 practice A test (electrolytic etching in 10% ammonium persulphate at 1 A/cm²) for various durations from 10 s to 90 s. The different degrees of intergranular corrosion attack produced on these tested specimens were evaluated by laser scattering technique using a 1 mW He-Ne laser. The scattering intensity pattern of the laser beam incident on the specimen was acquired using a CCD camera and transferred to a computer for further analysis. The specular intensity of the scattering pattern and its full width at half maximum (FWHM) was calculated. The results indicated that the specular intensity decreased and the FWHM increased as the degree of IGC attack increased. A good correlation was found between the extent of IGC with the laser scattering parameters.     

Sustained release of antibiotic from polyurethane coated implant materials

Implant associated infections are of increasing importance. To minimize the risks of implant-associated infections recent biomedical strategies have led to the modification of the medical device surfaces. The modifications are in the terms of increasing surface biocompatibility and decreasing bacterial adherence, which can be achieved by applying a coating of biocompatible polymer onto the said surfaces. Entrapping anti-infective agents in a polymer matrix provides an approach to kill bacteria and combat the possibility of any residual infection. We have prepared a biodegradable polyester urethane coat for implant materials, which have the property to accommodate antibiotics within itself. These polyurethane coating materials were characterized by FTIR spectroscopy, swelling property in SBF, gravimetric analysis, drug release, and biocompatibility study. Drug release rates, bacterial colonization and morphological features were also evaluated to predict and understand the antimicrobial activity of these delivery systems. Drug release characteristics were investigated and the physico-chemical mechanisms of the delivery were discussed. Results suggest that the polyester urethane can be used as an implant coating material and can be used as a matrix for the sustained delivery of anti-infective agent.     

Surface and Corrosion Characteristics of a-C:H/Fluorocarbon Films

Fluorocarbon films were deposited on type 301 stainless steel substrates from mixtures of hexafluoroethane (HFE) or hexafluoroacetone (HFA) and acetylene and argon in a radio-frequency (13.56 MHz) plasma discharge. A 10 nm thick polysilicon interlayer was deposited prior to fluorocarbon film deposition to obtain good adhesion. To prevent film failure. a-C:H layer was deposited on the polysilicon layer prior to fluorocarbon film deposition, resulting in a-C:H/fluorocarbon composite film structures. The influence of the feed gas composition on the properties of the layered structure was investigated. Surface energies of the films were calculated from the film contact angle values obtained with water and diiodomethane. The composition of the surface layer of these films was characterized using X-ray photoelectron spectroscopy (XPS). The resistance offered by these a-C:H/fluorocarbon film structures to anodic breakdown in an electrolyte containing 0.1 M NaCl and 0.1 M Na₂SO₄ was studied using a potentiostatic technique. The anodic current density for the coated type 301 stainless steel samples was at least 3 orders of magnitude smaller than that for the bare sample and more than an order of magnitude smaller than that observed with samples coated with only the (equally thick) a-C:H layer. The resistance offered by the layered coatings to solution penetration increased with increasing fluorine content in the films.     

Effect of tomato juice addition on the growth and activity of Lactobacillus acidophilus.

Addition of tomato juice to skimmed milk stimulated the growth of Lactobacillus acidophilus. It resulted in higher viable counts, shorter generation time and improved sugar utilization with more acid produced and lower pH for the strains tested. Varying results were obtained for the five strains examined.     

Influence of dietary capsaicin and onion on the metabolic abnormalities associated with streptozotocin induced diabetes mellitus

This case report describes a 3-year-old American Quarter Horse with acquired immunodeficiency. Clinical signs included chronic diarrhea due to Salmonella typhimurium and bacterial pneumonia. Characterization of the immunodeficiency involved in vivo phytohemagglutinin (PHA) intradermal testing, in vitro lymphocyte proliferation in response to concanavalin A, immunofluorescence flow cytometry data on blood lymphocytes, serum protein electrophoresis and immunoglobulin (Ig) quantification. A diagnosis of B lymphocyte deficiency with resulting deficiencies in serum IgG, IgA and IgM and a concurrent decrease in T cell function was made based on these tests. Postmortem examination revealed no evidence of lymphosarcoma. This case represents a variation of young adult-onset B cell deficiency not previously described in the literature.     

Antioxidant activity of some phenolic constituents from green pepper (Piper nigrum L.) and fresh nutmeg mace (Myristica fragrans)

Antioxidant potential of phenolic compounds from green pepper (Piper nigrum L.) and lignans from fresh mace (Myristica fragrans) were evaluated for their ability to scavenge 1,1′-diphenyl-2-picrylhydrazyl (DPPH) radical, inhibit lipid peroxidation and protect plasmid DNA damage upon exposure to gamma radiation. EC₅₀ values of the major phenolic compounds of green pepper namely, 3,4-dihydroxyphenyl ethanol glucoside, 3,4-dihydroxy-6-(N-ethylamino) benzamide and phenolic acid glycosides were found to be 0.076, 0.27 and 0.12 mg/ml, respectively, suggesting a high radical scavenging activity of these phenolics. These results were further confirmed with cyclic voltammetry. Acetone extract of nutmeg mace and its subsequent TLC isolated fractions constituted mainly of lignans as revealed by GC–MS analysis. The major compounds were tentatively identified from their mass spectral fragmentation pattern. DPPH radical scavenging capacity of the acetone extract as well as its fractions was comparatively lower than that of green pepper phenolics. In contrast, these fractions had a greater ability to inhibit lipid oxidation than phenolics from pepper as revealed by β-carotene–linoleic acid assay. A DNA protecting role of these compounds even at doses as high as 5 kGy further suggested the potential use of green pepper and fresh nutmeg mace and their extracts as a nutraceutical in preventing oxidative damage to cells.