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This paper describes a novel technique for the simultaneous measurement of the temperature of solid structures at multiple locations using a single transducer attached to a single bent waveguide with axisymmetric notches. This technique improves upon earlier reported studies using straight waveguides and bent waveguides without notches, where the lack of consideration for the effect of temperature gradients was found to be a significant limitation. This work also describes the L(0,1) and T(0,1) mode transmission and reception in the bent waveguide for selecting an appropriate gauge length for the waveguide sensor. The range of temperature measurement is from room temperature to the maximum utility temperature of the pipe structure in a process industry. The change in time-of-flight of the reflected ultrasonic signal from the waveguide features (bend and notch) is used to measure the local temperature of the surrounding media. This work is of interest in several industrial applications, including the petrochemical and nuclear industries. [ABSTRACT FROM AUTHOR]

Zn co-doped and undoped Y 2 O 3 -Eu red phosphor was prepared by citric acid gel method and it was investigated to know its cathodoluminesecent properties at low voltage excitation (<2 kVs). In this connection the cathodoluminescence (CL) spectra of Zn co-doped and undoped phosphors were taken and they showed various line emissions along with a sharp red emission at 611 nm, irrespective of Zn concentration, due to 5 D 0 – 7 F 2 transitions from Eu luminescent center. It was found that the incorporation of Zn could significantly enhance the CL emission intensity of Eu at about 33% when compared with Zn undoped phosphor. It was also found the Zn co-doping could not alter the crystal structure whereas it could change the morphology of the particles. The promising results revealed the possible application of this phosphor materials as red phosphor for field emission displays [FEDs]. [ABSTRACT FROM AUTHOR]

In this paper, a computational fluid dynamics optimization strategy-based surrogate model, which is used for the predictions of vertical aerodynamic force (Cl), is proposed. An airfoil shape optimization problem has been formulated, and the particle swarm optimization algorithm technique is used to solve the problem along with the inclusion of constructed surrogate model. This is used to replace the actual CFD algorithms. Ordinary kriging and Hammersley sequence sampling approach are applied to construct and enhance the effectiveness of the constructed surrogate model, respectively. The geometry of the airfoils (NACA 2411 and 0012) is described with the help of parametric section method, and the flow around the airfoils is solved by using the Panel method. The constructed surrogate model is more accurate and limits their estimation error within the order of 10-10. The computational time required to solve the formulated ASO problem, which will take 630 s while using a normal optimization scheme in a computer system which has 2GB of DDR3 RAM, 2.0GHz of processor speed, and 1MB of L2 cache memory, is drastically reduced to 56.7 s while using the surrogate-based optimization, and also, the optimized airfoils have improved Cl when compared to the original airfoils. The optimized airfoils were validated using experimental data. [ABSTRACT FROM AUTHOR]

The method of optimization algorithms is one of the most important parameters which will strongly influence the fidelity of the solution during an aerodynamic shape optimization problem. Nowadays, various optimization methods, such as genetic algorithm (GA), simulated annealing (SA), and particle swarm optimization (PSO), are more widely employed to solve the aerodynamic shape optimization problems. In addition to the optimization method, the geometry parameterization becomes an important factor to be considered during the aerodynamic shape optimization process. The objective of this work is to introduce the knowledge of describing general airfoil geometry using twelve parameters by representing its shape as a polynomial function and coupling this approach with flow solution and optimization algorithms. An aerodynamic shape optimization problem is formulated for NACA 0012 airfoil and solved using the methods of simulated annealing and genetic algorithm for 5.0 deg angle of attack. The results show that the simulated annealing optimization scheme is more effective in finding the optimum solution among the various possible solutions. It is also found that the SA shows more exploitation characteristics as compared to the GA which is considered to be more effective explorer. [ABSTRACT FROM AUTHOR]

Abstract: The functional behavior of manufactured surfaces is influenced by the errors such as roughness, waviness and form errors that are present on the surface. A filtering process is used to establish a three-dimensional reference surface consisting of waviness and form errors and the roughness component is separated with reference to it. The metrological characteristics of a filter are better understood in terms of wavelength content and phase information. In this paper, metrological characteristics of wavelet filter suggested for processing of engineering surfaces are discussed. A few typical manufactured surfaces and their reference surfaces established by wavelet filter are further analyzed by random process techniques to bring out the waviness content and phase matching. [Copyright &y& Elsevier]

High toughness epoxy resin hybrid composites were prepared using nanoclay, SiC, and glass‐caryota intra ply fibers. The main aim of this research was to study the effect of adding Caryota urens natural fiber from biomass as a potential fiber along with synthetic glass fiber in load‐bearing and wear properties of nanoclay and silicon carbide (SiC) particle toughened epoxy composite. The intra‐ply glass‐caryota fiber, silicon carbide, and nanoclay were surface‐treated using 3‐Aminopropyltrimethoxysilane. The composites were prepared using the hand lay‐up method. The tensile result shows that the addition of 1 vol% of the silicon carbide particle along with nanoclay in intra‐ply glass‐caryota fiber‐reinforced epoxy composite gives improved results than other composite designations. The wear properties show that the addition of silicon carbide of 1.0 vol% gives a lower specific wear rate of 0.024 mm3/Nm. Similarly, the composite, which contains 1.0 vol% of silicon carbide and nanoclay gives higher penetration resistance and energy absorption. In all properties, the addition of silicon carbide modifies the values significantly. This high toughness intra‐ply glass‐caryota fiber‐reinforced silicon carbide/nanoclay toughened epoxy resin composite could be used in automotive, sports components, domestic appliances, and structural body applications. [ABSTRACT FROM AUTHOR]