Non-destructive evaluation of plasma sprayed functionally graded thermal barrier coatings

Acoustic emission (AE) as a non-destructive evaluation technique has recently been used in a number of studies to investigate the performance and failure behavior of plasma sprayed thermal barrier coatings. The mechanism of coating failure is complex, especially when considering the composite nature of the coating. In the present paper, the thermal shock tests with in situ acoustic emission are used to study the cracking behavior of plasma sprayed functionally graded thermal barrier coatings. Each thermal cycle consists of 8 min heating in the furnace at 1000°C and 8 min cooling from 1000°C to the room temperature by a compressed air jet. The AE signals are recorded during the quench stage. Three, four and five layer functionally graded coatings have been tested. The results show that the five layer functionally graded coatings appear to have the best thermal shock resistance in the specimens tested, because of the gradual changes in material properties. Higher AE energy counts and cumulative counts recorded by the tests are associated with the macro-crack initiation and growth. On the other hand, micro cracking and phase transformation only give rise to lower AE signals.     

A fractional-step lattice Boltzmann flux solver for axisymmetric thermal flows

ABSTRACT

A fractional-step lattice Boltzmann flux solver is proposed in this work for effective simulation of axisymmetric thermal flows with rotating walls. The predictor and corrector steps are introduced in the solver. In the predictor step, excluding axisymmetric effects, the intermediate flow variables are predicted by the lattice Boltzmann flux solver (LBFS), which applies the finite-volume method to discretize the conservative equations recovered by the standard lattice Boltzmann method (LBM). The fluxes of the LBFS at the cell interfaces are reconstructed by local application of the lattice Boltzmann (LB) model with three distribution functions. These three distribution functions are used respectively for calculating axial and radial velocities, azimuthal velocity, and internal energy. In the corrector step, the intermediate flow variables are corrected by considering the axisymmetric effects. The present method not only retains the simplicity of the LBM but also eliminates the complicated derivation process in the axisymmetric LB model. The reliability of the proposed solver is examined by its application to simulate natural convection in an annulus, the Rayleigh-Benard convection, mixed convection in a vertical tall annulus, and Wheeler’s benchmark problem in crystal growth. The numerical results obtained agree well with the published data.     

Water services industry reforms in Malaysia

Concerted efforts to reform and transform the water industry in Malaysia began in 2006. It was a visionary effort by the federal government to ensure an adequate supply of clean water to the public and industry. A policy and institutional framework was created to re-invent and transform the water services industry into an efficient and sustainable sector that will play a pivotal role as one of the major components of economic growth. Though minor adjustments may be needed during its implementation, the overall policy direction is pragmatic and viable and has started to produce tangible outcomes.     

Predictive Simulation of Advanced Nano-CMOS Devices Based on kMC Process Simulation

In this paper, accurate and advanced CMOS process and device simulations based on atomistic kinetic Monte Carlo (kMC) process simulator are presented. First, the methodology used to predict continuum 2-D/3-D doping profiles from 3-D atomistic distribution that can be directly transferred from process to device simulator is described. Calibration of damage evolution, dopant diffusion and clustering, interaction with interfaces, and the impact of impurities, which are crucial for accurate simulations, will be presented and discussed. Subsequently, comparison with a wide range of electrical-device characteristics showed that experimental results were remarkably well reproduced by the simulations. Finally, we shall demonstrate that device optimization can be achieved based on kMC process simulations, even for novel coimplant processes. This paves the way for the use of kMC in the design of devices and the optimization of device performance in technology computer-aided design for manufacturing.     

Exploring dynamic self-adaptive populations in differential evolution

Although the Differential Evolution (DE) algorithm has been shown to be a simple yet powerful evolutionary algorithm for optimizing continuous functions, users are still faced with the problem of preliminary testing and hand-tuning of the evolutionary parameters prior to commencing the actual optimization process. As a solution, self-adaptation has been found to be highly beneficial in automatically and dynamically adjusting evolutionary parameters such as crossover rates and mutation rates. In this paper, we present a first attempt at self-adapting the population size parameter in addition to self-adapting crossover and mutation rates. Firstly, our main objective is to demonstrate the feasibility of self-adapting the population size parameter in DE. Using De Jong's F1–F5 benchmark test problems, we showed that DE with self-adaptive populations produced highly competitive results compared to a conventional DE algorithm with static populations. In addition to reducing the number of parameters used in DE, the proposed algorithm actually outperformed the conventional DE algorithm for one of the test problems. It was also found that that an absolute encoding methodology for self-adapting population size in DE produced results with greater optimization reliability compared to a relative encoding methodology.     

A Database Approach Integrating A Visually Interactive Load Flow For Low Voltage System

This paper presents an alternative approach to a visually interactive load flow and distribution loss calculation for a radially operated distribution network in buildings. By using the proposed database structure, any distribution network can be specified and modeled effectively, including the whole types and sizes of cables under different installation methods. Based on our proposed solution algorithm, matched with the database structure, load flow results can be calculated directly without formulating the admittance matrix. Thus, there is practically no limit to the number of nodes, and thus it does not require sparse techniques in matrix inversion. Any breaker in the network can be operated or tripped and a new load flow will be calculated and displayed. Based on the information in the database and a drawing algorithm, the single-line diagram of the network is drawn automatically and the calculated results can be dynamically positioned on the single line diagram. Test results confirm that the proposed system provides almost identical solution as compared with the conventional method.     

Ultrawide color gamut LCD display with CdSe/CdS nanoplatelets

We present a liquid‐crystal display (LCD) backlight made of nanoplatelets (NPLs) for the first time. Owing to the narrow emission linewidth of NPLs (8‐12 nm) and quantum dots (QDs), the spectrum exhibits a wide color gamut display with a 139.9% color gamut of National Television System Committee (NTSC) 1953 standard and 104.5% Rec.2020 (ITU‐R Recommendation BT.2020), realizing a truly ultrawide color gamut LCD display.     

Coordination arrival control for multi‐agent systems

The coordination arrival problems of first‐order multi‐agent systems with the arriving structure and the time structure requirements are considered for the cases with no obstacle and obstacle. To describe the distributed coordination arrival problems, we first introduce needed definitions, such as coordination arrival, threat point, and arrival structure. By selecting the estimated value of the arriving time of the agent as variable, we then develop a central estimating algorithm, which is used to construct the arriving protocols. Based on the estimating algorithm, we build and analyze coordination arriving protocols for the proposed coordination arrival problems. Several simulation examples are presented to validate the proposed algorithms. Copyright © 2015 John Wiley & Sons, Ltd.     

An empirical study of the impacts of integrating business planning and information systems planning

This study reports on a follow-up analysis of a prior study (Teo & King, 1996, Information and Management) of the impact of the integration of information systems planning (ISP) with business planning (BP) on organizational performance. The empirical data are re-analysed using path analysis in order to determine the direct and indirect impacts of BP-ISP integration on intermediate performance measures related to ISP process and output problems, as well as on five perceptual measures of organizational performance. The results empirically substantiate the importance of BP-ISP integration, since higher levels of integration were found to have a significant inverse relationship with the extent of both process and output varieties of ISP problems and a significant positive relationship with each of the five perceptual measures of the extent of IS contributions to overall organization performance.