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Article
Publication date: 1 January 1991

H. Ohdaira, K. Yoshida and K. Sasaoka

This paper reports on the development of a simple manufacturing process for polymeric multilayer substrates utilising the thermoplasticity of thermoplastic resin. Features…

Abstract

This paper reports on the development of a simple manufacturing process for polymeric multilayer substrates utilising the thermoplasticity of thermoplastic resin. Features and defects noted in manufacturing trials of the substrates are also reported. The process involves a polymer‐based thick film conductive paste screen printed on a hole‐punched thermoplastic resin film and dried. The films are stacked to form multiple layers and are then compressed into one unit. As the extremely thin thermoplastic resin film layers are equivalent to a single layer, a feature of this substrate is its exceptional thinness. As thermoplastic resin is used as a base material, the soldering process and other connecting technologies which may be used in place of solder connection are also examined.

Details

Circuit World, vol. 17 no. 2
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 1 December 1999

Marcos E.J. Bertin

Starting in the 1980s, South America went through dramatic political and economic changes. Military governments were replaced by democratic governments. These governments…

Abstract

Starting in the 1980s, South America went through dramatic political and economic changes. Military governments were replaced by democratic governments. These governments, forced by a severe crisis and the requirements of an increasingly competitive global economy, implemented, in the early 1990s, economic reforms based on free market principles and created the Mercosur. The major countries in this new and dynamic common market are Argentina and Brazil. In essence, these countries’ governments implemented policies conducive to competitiveness. As a result of these changes, quality became a key success factor for business. An increasing number of CEOs are becoming directly involved in quality. In Argentina, three institutions, created during the past ten years, are working in close co‐ordination to improve the country’s competitiveness. Similar activities are carried out in Brazil. A lot remains to be done in order to remain competitive in the increasingly difficult global markets.

Details

The TQM Magazine, vol. 11 no. 6
Type: Research Article
ISSN: 0954-478X

Keywords

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Article
Publication date: 19 July 2019

Na Li, Han Wang, Hui Xu and Mingfeng Miao

Ammonia injection grid (AIG) is used as an input device for ammonia which reacts with NOx in the selective catalytic reduction (SCR) reactor. However, non-uniform…

Abstract

Purpose

Ammonia injection grid (AIG) is used as an input device for ammonia which reacts with NOx in the selective catalytic reduction (SCR) reactor. However, non-uniform concentration distribution of ammonia could produce partially poisoning or deposits of the catalyst. In this work, for making ammonia widely distributed throughout the flue gas and fully mixed, an optimization method of AIG is proposed.

Design/methodology/approach

Depending on the complexity of fluid flow, the relation between the concentration distributions of ammonia and the geometric parameters of AIG is nonlinear. Based on a certain amount of AIG samples, the computational fluid dynamics (CFD) simulations are applied to propose the agent model which describes the functional relation of the deviation of ammonia concentration and the geometric parameters of AIG. The optimization model of AIG based on the agent model is established. The optimized AIG based on the agent model can be used to produce uniform concentration distributions of ammonia, especially in the case that velocity distribution of flue gas is non-uniform.

Findings

For qualitatively confirming this optimization method, the three-dimensional CFD simulation of the optimized AIG is carried out. The results reveal that the diffusion process of ammonia gas is consistent with the development of the local vortices, which have a certain relation with the velocity distribution of the flue gas. The unequal ammonia injection designed by the optimization based on the agent model promotes a better mixing of ammonia and flue gas.

Originality/value

In this work, first, the method for optimizing AIG based on the agent model is proposed. Second, the three-dimensional CFD modeling and simulation of the optimized AIG is carried out, and the mixing effects of ammonia and flue gas are presented.

Details

Engineering Computations, vol. 36 no. 9
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 27 July 2018

Bojana Nikolic, Bojan Dimitrijevic, Tino Hutschenreuther and Hannes Toepfer

The purpose of this paper is to analyze a signal propagation in highly metalized environments, which has not been extensively studied in the literature. Having in mind a…

Abstract

Purpose

The purpose of this paper is to analyze a signal propagation in highly metalized environments, which has not been extensively studied in the literature. Having in mind a large number of such applications, better understanding and possibly finding a way of improving communication in these conditions would be highly beneficial.

Design/methodology/approach

The analysis is performed in a simulation environment developed by the authors, based on finite difference time domain (FDTD) method, to identify effects that have decisive influence on electromagnetic (EM) wave propagation in the aforementioned conditions. The analysis of the EM field at the reception is modified so that a multiple-field sampling is performed, and maximal values are further used. In practical realizations, this procedure could be implemented by using multiple antennas and selective combining at the reception.

Findings

Results show that the existence of metal objects (in the observed case, these are railway tracks), in combination with the appropriate choice of antenna parameters, can be favorably used to improve signal reception. The contribution is manifested through the reduction of the pathloss.

Research limitations/implications

In the performed analysis, one should be aware of the limitations that the FDTD method brings. Those limitations are related to the size of the computational domain and discretization mesh refinement (possibility of modeling geometry in fine details).

Originality/value

Originality of this paper consists of the introduced modification in the analysis of signal propagation in heavily metalized environment. Namely, a multiple-field sampling in the reception zone (in one plane, dimensions λ × λ = 12.5 cm X 12.5 cm) is performed using several probes in simulation environment. In this way, a qualitative analysis is performed more efficiently, which made it is possible to distinguish and identify different propagation mechanisms.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 37 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

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Article
Publication date: 21 December 2017

Bing Bing Tu and Dong Zhao

The study of the character of structural hysteretic energy under earthquake is an essential foundation for energy-based seismic design and evaluation method. The purpose…

Abstract

Purpose

The study of the character of structural hysteretic energy under earthquake is an essential foundation for energy-based seismic design and evaluation method. The purpose of this paper is to explore the distribution law of the accumulative irrecoverable hysteretic energy for MDOF structures, a formula of the accumulated irrecoverable hysteretic energy ratio along the layers is derived.

Design/methodology/approach

The procedure is based on the energy balance principle and the concept of the equivalent single-degree-of-freedom system. Furthermore, sensitivity analysis is carried out for 16 working conditions, considering all these possibilities of local failure or damage. And then the sensitivity influencing rule is obtained and the proposed formula is simplified.

Findings

Finally, the validation of the proposed formula is investigated through comparisons with the nonlinear time-history analysis results.

Originality/value

The proposed formula can be effectively to estimate the distribution of the hysteretic energy under a given ground motion.

Details

Multidiscipline Modeling in Materials and Structures, vol. 14 no. 2
Type: Research Article
ISSN: 1573-6105

Keywords

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