La3.5Ru4.0O13 Perovskite type Catalyst for Carbon Monoxide and Hydrocarbon Oxidation

Ruthenium based catalysts show excellent catalytic activity for several oxidation reactions, however, their thermal stability has been a challenge. We have been successful in stabilizing ruthenium in perovskite structure, which results in a remarkable improvement in its thermal stability. La_3.5Ru_4.0O₁₃ lanthanum ruthenate type perovskite was prepared by using various methods, including co-precipitation as well as a template method, which resulted in improved physical properties. This perovskite phase was found to be thermally very stable, possibly due to the 4+ oxidation state of ruthenium in a stable matrix. In this work, we have studied the catalytic properties of La_3.5Ru_4.0O₁₃ phase for CO and hydrocarbon oxidation reactions. The lanthanum ruthenate shows active CO oxidation beyond about 150 and 170 °C for propene oxidation. The thermal and chemical stability of this material makes it suitable for various catalytic applications, while relatively insignificant poisoning by SO₂ is an important observation to further explore.     

Hydrodynamics of quenching with impinging free-surface jet

The hydrodynamics of jet impingement quenching of a stainless steel specimen has been studied experimentally. The specimen is heated to an initial temperature of about 900 °C and then quenched by a subcooled free-surface water jet. High-speed imaging shows that the free-surface of the water film in the wetted region is smooth. The water film outside the wetted region is deflected away from the surface and then breaks into droplets due to surface tension and shear forces. The splashed droplet velocity is found to be low up to a wetting front radius of 6 mm (r/d_J ≈ 2), beyond which it increases rapidly before reaching a constant value at a wetting front radius of about 8 to 10 mm (2.67 ? r/d_J ? 3.34). The water film velocity at the wetting front is calculated using the single-phase boundary layer model suggested by Watson [2]. At moderate subcooling, the splashed droplet velocity up to a wetting front radius of 10 mm (r/d_J ≈ 3.34) is found to be much lower than the estimated single-phase film velocity. The study shows that although the wetted region may appear devoid of any bubbles, strong two-phase flow occurs within this region.     

Improved Sliding-Wear Resistance in In Situ-Toughened Silicon Carbide

The effect of microstructure on the sliding-wear properties has been studied in two types of pressureless liquid-phase-sintered (LPS) SiC ceramics, one with coarse, in situ -grown elongated grains and the other with fine, equiaxed grains. Elongated-grain LPS SiC has been found to have dramatically improved sliding-wear properties over equiaxed-grain LPS SiC, which has been attributed to the interlocking network of elongated SiC grains. The introduction of an interlocking network of elongated grains represents a new guideline for the microstructural design of polycrystalline ceramics that are both sliding-wear resistant and toughened.     

Analysis of a counter-current vapor flow absorber

Analytical investigation of a combined heat and mass transfer process in a counter-current ammonia-water based absorber is presented. The model accounts for both liquid and vapor phase mass transfer resistances, and uses empirical correlations to predict the heat and mass transfer coefficients. The model was used to analyze a lamella plate based absorber with falling film absorption. A finite difference technique was employed to solve the numerical model. It was found that the major portion of the mass transfer resistance lies primarily in the liquid phase. A parametric analysis was also conducted to assess the effect of various parameters on the performance of the absorber.     

Quantitative Phase-Composition Analysis of Liquid-Phase-Sintered Silicon Carbide Using the Rietveld Method

Accurate quantitative X-ray diffraction analysis of SiC-based ceramics is difficult because of the significant overlap of the Bragg reflections from the different SiC polytypes. In this regard, the Rietveld method is a powerful tool for the accurate and precise analysis of the phase/polytype compositions in these materials. In this study, we have used two different types of Rietveld codes for the quantitative phase/polytype analysis of a liquid-phase-sintered SiC specimen: FULLPROF, which is based on the classical Rietveld approach, and BGMN, which is based on the new fundamental parameter approach. In both cases, the effect of texture corrections on the precision of the analysis also was studied. The accuracy of the analysis, in terms of the weight percentage of SiC (all polytypes) and yttrium aluminum garnet liquid phase, as determined from the starting powder composition, is within the standard deviation of the analysis in both cases (FULLPROF and BGMN), with and without the texture corrections. In addition, in the case of the classical code (FULLPROF), inclusion of the texture corrections has been shown to improve the precision. In contrast, the precision of the analysis using the BGMN code without the texture corrections is better. However, inclusion of the texture corrections is expected to improve the accuracy of the analysis.     

Parameter convergence in adaptive feedback linearizing control of limit cycling systems with input saturation

Adaptive feedback linearizing control schemes are used to suppress limit cycle oscillations in nonlinear systems where the system parameters are either unknown or uncertain. Parameter convergence is desirable in these schemes as it provides a measure of robustness of the scheme and also permits the unknown/uncertain system parameters to be estimated. In recent work, we have shown how using a persistently exciting forcing it is possible to achieve parameter convergence in nonlinear limit cycling systems. In practice, however, limits on the control input to the plant due to saturation must be considered, and the main goal of this work is to analyze the effect of input saturation on parameter convergence in an adaptive feedback linearization framework. In particular, a technique known as control hedging is incorporated and the effectiveness of this method for very severe saturation constraints has been evaluated. Results are presented for a single degree-of-freedom wing rock dynamics model and a multi degree-of-freedom combustion acoustics model showing successful parameter convergence even in the presence of input saturation.     

Electricity price classification using extreme learning machines

Forecasting electricity prices has been a widely investigated research issue in the deregulated power market scenario. High price volatilities, price spikes caused by a number of factors such as weather uncertainty, fluctuating fuel prices, transmission bottlenecks, etc., make the task of accurate price forecasting a formidable challenge for the market participants. A number of models have been proposed by researchers; however, achieving high accuracy is always not possible. In some specific applications such as self-scheduling by demand side participants, certain price thresholds are more useful than accurate price forecasts. In this paper, we have investigated the application of a novel neural network-based technique called extreme learning machine for the problem of classification of future electricity prices with respect to certain price thresholds. Different models corresponding to different lead times are developed and tested with data corresponding to Ontario and PJM markets. It is observed that classification with ELM is fast, less sensitive to user defined parameters and easily implementable.     

High-Cycle Fatigue Behavior of Microarc Oxidation Coatings Deposited on a 6061-T6 Al Alloy

The objective of this article is to evaluate the influence of microarc oxidation (MAO) coatings on the high-cycle rotating bending fatigue behavior of the 6061-T6 aluminum alloy. Toward this purpose, the influence of the MAO coating process parameter (current density) and coating thickness on the fatigue life of the 6061-T6 Al alloy has been evaluated in the present study. In addition, the influence of the coating roughness on the fatigue life of the MAO-coated 6061-T6 Al-alloy sample has also been investigated. The results indicate that the high-cycle fatigue life of the 6061-T6 Al alloy is substantially degraded due to the presence of MAO coatings, especially at lower alternating stress values and for thicker coatings. Surface roughness, altered by polishing, does not have any effect on fatigue life. An examination of coated samples interrupted at various fractions of fatigue life leads to the conclusion that the crack propagates from the coating surface to the coating-substrate interface very rapidly and thus fatigue life is largely controlled by the propagation of the crack into the substrate.     

TER-Plus: paraphrase, semantic, and alignment enhancements to Translation Edit Rate

This paper describes a new evaluation metric, TER-Plus (TERp) for automatic evaluation of machine translation (MT). TERp is an extension of Translation Edit Rate (TER). It builds on the success of TER as an evaluation metric and alignment tool and addresses several of its weaknesses through the use of paraphrases, stemming, synonyms, as well as edit costs that can be automatically optimized to correlate better with various types of human judgments. We present a correlation study comparing TERp to BLEU, METEOR and TER, and illustrate that TERp can better evaluate translation adequacy.     

Structural and microfluidic analysis of hollow side-open polymeric microneedles for transdermal drug delivery applications

In this paper, we present a new design of hollow, out-of-plane polymeric microneedle with cylindrical side-open holes for transdermal drug delivery (TDD) applications. A detailed literature review of existing designs and analysis work on microneedles is first presented to provide a comprehensive reference for researchers working on design and development of micro-electromechanical system (MEMS)-based microneedles and a source for those outside the field who wish to select the best available microneedle design for a specific drug delivery or biomedical application. Then, the performance of the proposed new design of microneedles is numerically characterized in terms of microneedle strength and flow rate at applied inlet pressures. All the previous designs of hollow microneedles have side-open holes in the lumen section with no integrated reservoir on the same chip. We have proposed a new design with side-open holes in the conical section to ensure drug delivery on skin insertion. Furthermore, the present design has an integrated drug reservoir on the back side of the microneedles. Since MEMS-based, hollow, side-open polymeric microneedles with integrated reservoir is a new research area, there is a notable lack of applicable mathematical models to analytically predict structural and fluid flow under various boundary conditions. That is why, finite element (FE) and computational fluid dynamic (CFD) analysis using ANSYS rather than analytical systems has been used to facilitate design optimization before fabrication. The analysis has involved simulation of structural and CFD analysis on three-dimensional model of microneedle array. The effect of axial and transverse loading on the microneedle during skin insertion is investigated in the stress analysis. The analysis predicts that the resultant stresses due to applied bending and axial loads are in the safe range below the yield strength of the material for the proposed design of the microneedles. In CFD analysis, fluid flow rate and pressure drop in the microneedles at applied inlet pressures are numerically and theoretically investigated. The CFD analysis predicts uniform flow through the microneedle array for each microneedle. Theoretical and numerical results for the flow rate and pressure drop are in close agreement with each other, thereby validating the CFD analysis. For the proposed design of microneedles, feasible fabrication techniques such as micro-hot embossing and ultraviolet excimer laser methods are proposed. The results of the present theoretical study provide valuable benchmark and prediction data to fabricate optimized designs of the polymeric, hollow microneedles, which can be successfully integrated with other microfluidic devices for TDD applications.