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Article
Publication date: 1 April 1993

L. Guan, C. Pusarla, G. Halkias and A. Christou

As speed and complexity of electronic systems increase, the interconnect density has become the critical limitation to the performance of electrical systems. The…

Abstract

As speed and complexity of electronic systems increase, the interconnect density has become the critical limitation to the performance of electrical systems. The performance of computing and switching systems can be increased by optimizing the interconnect density and throughput. At the board to board level, electrical interconnects at high speeds require a bulky and expensive backplane. At the chip to chip area, the allocation of interconnects limits the performance of the chips. Electrical lossy lines limit the maximum interconnect distance due to reflections, risetime degradation, increased delay, attenuation and cross talk . Optical interconnects present the possibility of solving the interconnect problems by potentially achieving a high bandwidth and high volume density of channels. At high data rates (greater than 1 Gb/s) several channels may operate with negligible mutual interference.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 12 no. 4
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 December 2003

Happy T. Holden

High density interconnect (HDI) printed circuits are now being designed in ever‐increasing quantities for very high‐speed applications. The challenge of opto‐electronics…

Abstract

High density interconnect (HDI) printed circuits are now being designed in ever‐increasing quantities for very high‐speed applications. The challenge of opto‐electronics and integration of photonics into the printed circuit has started to take off. In the next 7 years, expectations are that photonic printed circuit boards will grow to a $2.5 billion industry. This paper looks at the issues, materials and current processes being researched by European, Japanese and North American organizations to create this integrated opto‐electronic circuit board. In addition to reviewing the global players in polymer photonics, this paper will review the current programs of four of the six groups globally, namely EOBC‐OptoFoil (University of Ulm, Fraunhafer Inst., Daimler‐Chrysler, Siemens), PolyGuide (Dupont, HP), TOPCat (NIST, 3M, Goodyear), Truemode™ (Terahertz), NTT and JIEP.

Details

Circuit World, vol. 29 no. 4
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 6 February 2007

Jim Hutchison and Sidhartha R. Das

To examine and analyze the decision process that a firm undergoes for acquiring an advanced manufacturing system to obtain manufacturing flexibility for its operations.

Abstract

Purpose

To examine and analyze the decision process that a firm undergoes for acquiring an advanced manufacturing system to obtain manufacturing flexibility for its operations.

Design/methodology/approach

A case study approach is used to examine these decision processes. A conceptual contingency‐based framework from the literature is used to guide the analysis. The framework proposes that four exogenous variables – strategy, environmental factors, organizational attributes, and technology – guide a firm's decisions on choice and adoption of manufacturing flexibility, which has an effect on the firm's performance.

Findings

The analysis shows that these decisions are aligned with the various relationships in the framework. The framework therefore helps understand and explain the above decision processes. Further, the paper expands the concept of “fit” between the variables in the framework.

Research limitations/implications

Several research propositions are developed based on the findings of this study. The findings in this paper are limited to this case study only. The paper does not attempt to validate theory but applies it in the context of examining and analyzing a company's decisions.

Practical implications

The suggested relationships in the conceptual framework are found to be applicable in a business setting. Practitioners can use the conceptual framework to guide them in making decisions when acquiring advanced manufacturing systems to obtain manufacturing flexibility.

Originality/value

This case study captures richness and detail in the decision‐making processes of an individual firm that are missed by other types of research studies. It helps both academics and practitioners to gain a better understanding of these processes.

Details

International Journal of Operations & Production Management, vol. 27 no. 2
Type: Research Article
ISSN: 0144-3577

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Article
Publication date: 1 April 2000

Jian‐Guo Zhang, A.B. Sharma, Yu‐De Ni and Zheng Li

The design issues on network architecture and modulation scheme that can be used to implement reliable MIL‐STD‐1773 avionics optical fiber data buses are discussed. Both…

Abstract

The design issues on network architecture and modulation scheme that can be used to implement reliable MIL‐STD‐1773 avionics optical fiber data buses are discussed. Both single‐star and multi‐star architectures are presented to such optical fiber data buses. Several network configurations based on passive and/or active coupling components are also considered, and they are compared in terms of system complexity and reliability. Moreover, three modulation schemes are presented, i.e. partial trilevel Manchester II bi‐phase coding, extended Manchester II bi‐phase coding with beginning‐stopping flags, and pseudo‐four‐ary pulse width modulation, respectively. Their use can feasibly solve the problem associated with fast identification of correct operation states of an active transmitter at the output of optical receivers.

Details

Aircraft Engineering and Aerospace Technology, vol. 72 no. 2
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 24 April 2007

Brajesh Kumar Kaushik, Saurabh Goel and Gaurav Rauthan

To review and explore optical fiber and carbon nanotube (CNT) as prospective alternatives to copper in VLSI interconnections.

Abstract

Purpose

To review and explore optical fiber and carbon nanotube (CNT) as prospective alternatives to copper in VLSI interconnections.

Design/methodology/approach

As the technology moves to deep submicron level, the interconnect width also scales down. Increasing resistivity of copper with scaling and rising demands on current density drives the need for identifying new wiring solutions. This paper explores various alternatives to copper. Metallic CNTs, optical interconnects are promising candidates that can potentially address the challenges faced by copper.

Findings

Although, the theoretical aspects proves CNTs and optical interconnect to be better alternative against copper on the ground of performance parameters such as power dissipation, switching delay, crosstalk. But copper would last for coming decades on integration basis.

Originality/value

This paper reviews the state‐of‐the‐art in CNT interconnect and optical interconnect research; and discusses both the advantages and challenges of these emerging technologies.

Details

Microelectronics International, vol. 24 no. 2
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 30 December 2020

Sayuj Sasidharan and Pradip Dutta

This paper aims to deal with characterisation of the thermal performance of a hybrid tubular and cavity solar thermal receiver.

Abstract

Purpose

This paper aims to deal with characterisation of the thermal performance of a hybrid tubular and cavity solar thermal receiver.

Design/methodology/approach

The coupled optical-flow-thermal analysis is carried out on the proposed receiver design. Modelling is performed in two and three dimensions for estimating heat loss by natural convection for an upward-facing cavity. Heat loss obtained in two dimensions by solving coupled continuity, momentum and energy equation inside the cavity domain is compared with the loss obtained using an established Nusselt number correlation for realistic receiver performance prediction.

Findings

It is found that radiation emission from a heated cavity wall to the ambient is the dominant mode of heat loss from the receiver. The findings recommend that fluid flow path must be designed adjacent to the surface exposed to irradiation of concentrated flux to limit conduction heat loss.

Research limitations/implications

On-sun experimental tests need to be performed to validate the numerical study.

Practical implications

Numerical analysis of receivers provides guidelines for effective and efficient solar thermal receiver design.

Social implications

Pressurised air receivers designed from this method can be integrated with Brayton cycles using air or supercritical carbon-dioxide to run a turbine generating electricity using a solar heat source.

Originality/value

The present paper proposes a novel method for coupling the flux map from ray-tracing analysis and using it as a heat flux boundary condition for performing coupled flow and heat transfer analysis. This is achieved using affine transformation implemented using extrusion coupling tool from COMSOL Multiphysics software package. Cavity surface natural convection heat transfer coefficient is obtained locally based on the surface temperature distribution.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 1 February 1988

D.H. Hartman

Fundamental engineering limits to very high speed electronics switching systems are employed. These limitations are caused by packaging and interconnection constraints, as…

Abstract

Fundamental engineering limits to very high speed electronics switching systems are employed. These limitations are caused by packaging and interconnection constraints, as well as device switching speed. From the device viewpoint, reactive parasitics caused by the packaging/interconnection scenario are discussed. From the systems level perspective, overall delay, delay variance and power consumption are explored. The important problem of clock distribution in high speed synchronous digital systems is discussed. These limitations are then revisited with photonics implementation in mind. Comparisons are made between the electrical and photonic approaches. Some engineering limits to the photonic alternative are laid out.

Details

Microelectronics International, vol. 5 no. 2
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 1 August 2016

Chih-Ta Yen and Guan-Jie Huang

The purpose of this paper is to propose a new optical steganography framework that can be applied to public optical binary phase-shift keying (BPSK) systems by…

Abstract

Purpose

The purpose of this paper is to propose a new optical steganography framework that can be applied to public optical binary phase-shift keying (BPSK) systems by transmitting a stealth spectrum-amplitude-coded optical code-division multiple-access signal through a BPSK link.

Design/methodology/approach

By using high-dispersion elements, the stealth data pulses temporally stretch and the amplitude of the signal decreases after stretching. Thus, the signal can be hidden underneath the public signal and system noise. At the receiver end, a polarizer is used for removing the public BPSK signal and the stealth signal is successfully recovered by a balanced detector.

Findings

In a simulation, the bit-error rate (BER) performance improved when the stealth power increased.

Research limitations/implications

The BER performance worsens when the noise power become large. Future work will consider increasing the system performance during high-noise power situation.

Practical implications

By properly adjusting the power of the amplified spontaneous emission noise, the stealth signal can be hidden well in the public channel while producing minimal influence on the public BPSK signal.

Originality/value

In conclusion, the proposed optical steganography framework makes it more difficult for eavesdroppers to detect and intercept the hidden stealth channel under public transmission, even when using a dispersion compensation scheme.

Details

Engineering Computations, vol. 33 no. 6
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 4 January 2021

Varinder Kumar and Santosh Bopche

This paper aims to present the numerical models and experimental outcomes pertain to the performance of the parabolic dish concentrator system with a modified cavity-type…

Abstract

Purpose

This paper aims to present the numerical models and experimental outcomes pertain to the performance of the parabolic dish concentrator system with a modified cavity-type receiver (hemispherical-shaped).

Design/methodology/approach

The numerical models were evolved based on two types of boundary conditions; isothermal receiver surface and non-isothermal receiver surface. For validation of the numerical models with experimental results, three statistical terms were used: mean of absolute deviation, R2 and root mean square error.

Findings

The thermal efficiency of the receiver values obtained using the numerical model with a non-isothermal receiver surface found agreeing well with experimental results. The numerical model with non-isothermal surface boundary condition exhibited more accurate results as compared to that with isothermal surface boundary condition. The receiver heat loss analysis based on the experimental outcomes is also carried out to estimate the contributions of various modes of heat transfer. The losses by radiation, convection and conduction contribute about 27.47%, 70.89% and 1.83%, in the total receiver loss, respectively.

Practical implications

An empirical correlation based on experimental data is also presented to anticipate the effect of studied parameters on the receiver collection efficiency. The anticipations may help to adopt the technology for practical use.

Social implications

The developed models would help to design and anticipating the performance of the dish concentrator system with a modified cavity receiver that may be used for applications e.g. power generation, water heating, air-conditioning, solar cooking, solar drying, energy storage, etc.

Originality/value

The originality of this manuscript comprising presenting a differential-mathematical analysis/modeling of hemispherical shaped modified cavity receiver with non-uniform surface temperature boundary condition. It can estimate the variation of temperature of heat transfer fluid (water) along with the receiver height, by taking into account the receiver cavity losses by means of radiation and convection modes. The model also considers the radiative heat exchange among the internal ring-surface elements of the cavity.

Details

World Journal of Engineering, vol. 18 no. 2
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 20 March 2017

Lujun Cui, Huichao Shang, Yan-long Cao and Gao-feng Zhou

Long life and high hydrogen sensitivity are the crucial performance parameters for an optical fiber hydrogen sensing membrane, and these are the fundamental areas of study…

Abstract

Purpose

Long life and high hydrogen sensitivity are the crucial performance parameters for an optical fiber hydrogen sensing membrane, and these are the fundamental areas of study for an optical fiber hydrogen sensor. Considering that a traditional optical fiber hydrogen sensor based on pure palladium cannot meet the expectations for long life and rapid sensitivity simultaneously, the experiment in this paper designed a kind of reflective optical fiber bundle hydrogen gas sensor based on a Pd0.75–Ag0.25 alloy to achieve a hydrogen sensing system. This paper aims to discuss the issues with this system.

Design/methodology/approach

A reflective optical fiber bundle hydrogen sensor was made up of an optical fiber bundle and a Pd0.75–Ag0.25 alloy hydrogen membrane. A combination of optical fiber light intensity measurements and the reference calculation method were used to extract the hydrogen concentration information from within the optical fiber, and the relationship between the hydrogen concentration changes and the reflective light intensity in the optical fiber was established.

Findings

The reflective optical fiber bundle hydrogen gas sensor based on a Pd–Ag alloy membrane was shown to provide an effective way to detect hydrogen concentrations. The experimental results showed that a 20-30-nm-thick Pd0.75–Ag0.25 alloy membrane could reach high hydrogen absorption and sensitivity. Key preparation parameters which included sputtering time and substrate temperature were used to prepare the hydrogen membrane during the DC sputtering process, and the reflectivity of the Pd–Ag alloy membrane was enough to meet the requirements of long life and high hydrogen sensitivity for the optical fiber hydrogen sensor.

Originality/value

This paper seeks to establish a foundation for optimizing and testing the performance of the Pd–Ag alloy hydrogen sensing membrane for an optical fiber bundle hydrogen sensor. To this end, the optimal thickness and key preparation parameters for the Pd–Ag alloy hydrogen sensing membrane were discussed. The results of this research have proved that the reflective optical fiber hydrogen sensor based on a Pd0.75–Ag0.25 alloy is an effective approach and precisely enough for hydrogen gas monitoring in practical engineering measurements.

Details

Sensor Review, vol. 37 no. 2
Type: Research Article
ISSN: 0260-2288

Keywords

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