Study of Kinetics of Mill Scale Reduction: For PM Applications

In the deep drawing process, material of blank is transformed into the desired complicated shape by a punch. In this paper, a technique for increasing the drawability of AA1200 aluminium alloy cylindrical cups has been developed. Effects of die and punch geometry including die and punch fillet radius, on limiting drawing ratio (LDR), drawing load with respect to punch stroke and strain of the cup wall have been investigated numerically for optimal process design. A commercial finite element simulation package, ANSYS 14.0, is used in order to determine the optimum limiting drawing ratio. An experimental setup is built accordingly with a half cone angle of 18°. In the experimental and finite element analysis, AA 1200 alloy sheets are used. The effects of the original blank thickness (t = 2 mm) on the various LDR and punch load are numerically investigated. The present process successfully produces cylindrical cups with drawing ratio of 2.64.     

Electrically Insulative Performances of Ceramic and Clay Films Deposited via Supersonic Spraying

Supersonic spray coating techniques were applied to deposit ceramic and clay particles as films for use in electrical insulation. TiO₂ and Al₂O₃ ceramics were aerosol-deposited under vacuum while kaolinite, montmorillonite, and bentonite clays were deposited by cold spraying in open air. The electrical resistivity of Al₂O₃ and TiO₂ were ~10⁹ and ~10⁸ Ω cm, respectively. The resistivity of kaolinite and montmorillonite were ~10¹² Ω cm. Bentonite showed the lowest electrical resistivity of ~10⁹ Ω cm among the clays because of the high cation exchange capacity of the material. The film surface morphologies and mechanical properties in the form of hardness and scratchability were also investigated.     

Gelation of methylcellulose hydrogels under isothermal conditions

The current work deals with the gelation of methylcellulose (MC) in aqueous solutions under isothermal conditions. The isothermal gelation was monitored during two consecutive heating and cooling cycles. The gelation was observed to occur early during the second cycle and progress at a higher rate. Micelle‐like structures were found to form in MC solutions during the first gelation cycle. These were largely responsible for the accelerated gelation during the second heating cycle. The influence from the state of water was examined by studying the gelation phenomenon for MC using either cold or hot DI water as solvent. The possible mechanism involved is discussed. A gel indexing method was established to provide a quantitative measure for the state of gelation achievable using different MC concentrations with either cold or hot water solvent. Stabilization kinetics for the gel under isothermal conditions was described using the Malkin and Kulichikhin model. The kinetics parameters were determined. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Final Shape of Precision Molded Optics: Part I—Computational Approach,Material Definitions and the Effect of Lens Shape

Coupled thermomechanical finite element models were developed in ABAQUS to simulate the precision glass lens molding process, including the stages of heating, soaking, pressing, cooling and release. The aim of the models was the prediction of the deviation of the final lens profile from that of the mold, which was accomplished to within one-half of a micron. The molding glass was modeled as viscoelastic in shear and volume using an n-term, prony series; temperature dependence of the material behavior was taken into account using the assumption of thermal rheological simplicity (TRS); structural relaxation as described by the Tool-Narayanaswamy-Moynihan (TNM)-model was used to account for temperature history dependent expansion and contraction, and the molds were modeled as elastic taking into account both mechanical and thermal strain. In Part I of this two-part series, the computational approach and material definitions are presented. Furthermore, in preparation for the sensitivity analysis presented in Part II, this study includes both a bi-convex lens and a steep meniscus lens, which reveals a fundamental difference in how the deviation evolves for these different lens geometries. This study, therefore, motivates the inclusion of both lens types in the validations and sensitivity analysis of Part II. It is shown that the deviation of the steep meniscus lens is more sensitive to the mechanical behavior of the glass, due to the strain response of the newly formed lens that occurs when the pressing force is removed.     

Intensity Distribution Across a Source from Spectral Measurements

Abstract

The degree of spectral coherence (μ₁₂(ω)) over the plane of a double slit is determined from the measurement of spectral changes in Young's interference experiment using the spectral interference law. The experimental and theoretically calculated values of μ₁₂(ω)) for the experimental parameters agree well within experimental error, thus supporting the theoretical prediction of D. F. V. James and E. Wolf (1991, Phys. Lett. A, 157 6). The degree of spectral coherence determined is used for estimating the intensity distribution across a source. This new approach, being a simple spectral measurement technique, might find its application in astronomy, particularly for the study of intensity distribution across stars.     

Dynamic single-machine scheduling under distributed decision-making

This paper presents a deterministic dynamic model for the single-machine scheduling problem. The model uses forecasts of future job arrivals with the current data to extract job interactions over time, updating the information on rolling basis. The model is implemented in a distributed structure with both the machine and the jobs involved in decision-making to create a schedule. The decision-making is modelled similar to an auction with a theoretical basis for problem decomposition, bid construction and bid evaluation. Numerical results indicate that the model outperforms other distributed implementations in both static and dynamic implementations for a wide range of single-machine scheduling problems.     

Spray dried formulation of mesalamine embedded with probiotic biomass for the treatment of ulcerative colitis: in-vitro and in-vivo studies

Abstract

This study is using the targeted approach and anti-inflammatory action of the probiotic biomass to lessen the side effects of therapeutic agents of ulcerative colitis. The aim of the present study is to prepare mesalamine loaded eudragit S-100 with probiotic microparticles by spray drying method. The in-vitro release of the optimized formulation was 90.55?±?2.42 in 24?hr, which display controlled drug release of mesalamine at a particular region. Mesalamine loaded eudragit S-100 with probiotic microparticles (F12) presented average particle size of 4.91?µm. The statistical analysis was done by one way ANOVA and then comparison test of Bonferroni was done and p values <.05 were considered as significant. The effects of spray dried microparticles over inflamed Caco-2 cell were also evaluated by determining the concentration of IL-8. From in-vivo study it was seen that pretreatment of mesalamine with probiotic prevents DNBS (Dinitrobenzenesulfonic acid) induced colitis in rats and represents protective action against ulcerative colitis because of its antioxidant and anti-inflammatory actions. The results give the foundation for a combination of targeted approach along with the anti-inflammatory potential of the probiotic which might help to decrease the problems which are seen with the traditional cure and management of ulcerative colitis.     

使用一个微控制器管脚的三态开关界面

电子小玩意儿的人机界面需要三种用于控制的状态。单轴摇杆的状态可定义向右、向左的运动，以及无动作。同样，有控制键的定时器可以使之增加、减小或保持不变。工程师一般使用两种独立按键建立这些界面，