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Article
Publication date: 8 April 2019

Yuan Ding, TongChun Li, LanHao Zhao, MinZhe Zhou and ChaoNing Lin

Multi-level intake structures are used to take the surface water of reservoirs. The changed boundary conditions will certainly make the water hammer phenomenon more…

Abstract

Purpose

Multi-level intake structures are used to take the surface water of reservoirs. The changed boundary conditions will certainly make the water hammer phenomenon more complicated. This paper aims to find out the influence and law of the water hammer pressure after setting the stop log gates.

Design/methodology/approach

The authors use the computational fluid dynamics method with the adaptive grid technology to stimulate the water hammer phenomenon of the multi-level intake hydropower station. In the analysis, we set several different heights of stop log gates and two representative times in the starting up and shutdown processes to reflect the impact of multi-level intake structures.

Findings

The authors find that the setting of the stop log gates will reduce the pressure during the normal operation and will increase the period and amplitude of the water hammer wave, but will not necessarily increase the maximum water hammer pressure during the shutdown process. The relationship between the height of the stop log gates and the amplitude of the water hammer wave is affected by the shutdown time. After setting stop log gates, the depression depth and wave height of the water level in front of the dam increase when the load changes.

Originality/value

The authors study in this paper the water pressure of the multi-level intake hydropower station that has never been studied before and obtain some laws.

Details

Engineering Computations, vol. 36 no. 3
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 December 2002

Soma Hewa

Ponders on whether Abraham Flexner was responsible for the change in medical education in North America in the early 20th century, owing to his report of 1910. Tries to…

Abstract

Ponders on whether Abraham Flexner was responsible for the change in medical education in North America in the early 20th century, owing to his report of 1910. Tries to demonstrate that medical education in the USA was part of a greater whole of major changes at that time. Concludes, though there was a philanthropic influence, Flexner (who refused to accept credit for change) was not the father of the medical reform plan.

Details

International Journal of Sociology and Social Policy, vol. 22 no. 11/12
Type: Research Article
ISSN: 0144-333X

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Article
Publication date: 2 January 2018

P. Pandiyan, G. Uma and M. Umapathy

This paper aims to present a design and simulation of electrostatic nanoelectromechanical system (NEMS)-based logic gates using laterally actuated cantilever with…

Abstract

Purpose

This paper aims to present a design and simulation of electrostatic nanoelectromechanical system (NEMS)-based logic gates using laterally actuated cantilever with double-electrode structure that can implement logic functions, similar to logic devices that are made of solid-state transistors which operates at 5 V.

Design/methodology/approach

The analytical modeling of NEMS switch is carried out for finding the pull-in and pull-out voltage based on Euler-Bernoulli’s beam theory, and its numerical simulation is performed using finite element method computer-aided design tool COVENTORWARE.

Findings

This paper reports analytical and numerical simulation of basic NEMS switch to realize the logic gates. The proposed logic gate operates on 5 V which suits well with conventional complementary metal oxide semiconductor (CMOS) logic which in turn reduces the power consumption of the device.

Originality/value

The proposed logic gates use a single bit NEMS switch per logic instead of using 6-14 individual transistors as in CMOS. One exclusive feature of this proposed logic gates is that the basic NEMS switch is structurally modified to function as specific logic gates depending upon the given inputs.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 37 no. 1
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 5 March 2018

Pandiyan P., Uma G. and Umapathy M.

The purpose of this paper is to design an out-of-plane micro electro-thermal-compliant actuator based logic gates which work analogously to complementary metal oxide…

Abstract

Purpose

The purpose of this paper is to design an out-of-plane micro electro-thermal-compliant actuator based logic gates which work analogously to complementary metal oxide semiconductor (CMOS) based logic gates. The proposed logic gates used a single-bit mechanical micro ETC actuator per logic instead of using 6-14 individual transistors as in CMOS.

Design/methodology/approach

A complete analytical modelling is performed on a single ETC vertical actuator, and a relation between the applied voltage and the out-of-plane deflection is derived. Its coupled electro-thermo-mechanical analysis is carried out using micro electro mechanical system (MEMS) CAD tool CoventorWare to illustrate its performance.

Findings

This paper reports analytical and numerical simulation of basic MEMS ETC actuator-based logic gates. The proposed logic gate operates on 5 V, which suits well with conventional CMOS logic, which in turn reduces the power consumption of the device.

Originality/value

The proposed logic gates uses a single-bit MEMS ETC actuator per logic instead of using more transistors as in CMOS. The unique feature of this proposed logic gates is that the basic mechanical ETC actuator is customized in its structure to function as specific logic gates depending upon the given inputs.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 37 no. 2
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 April 2006

Colin Rogers

Alley gating schemes have been given impetus by government funding. A simple causal relationship is assumed by the presence of the gates and a reduction in crime and…

Abstract

Alley gating schemes have been given impetus by government funding. A simple causal relationship is assumed by the presence of the gates and a reduction in crime and disorder. The post‐implementation research discussed in this article shows that implementation and installation decisions may have unintended consequences for the displacement of problems and the creation of new signal crimes in areas subject to alley gating.

Details

Safer Communities, vol. 5 no. 2
Type: Research Article
ISSN: 1757-8043

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Article
Publication date: 20 April 2015

Yexiang Xiao, Zhengwei Wang, Jidi Zeng, jintai Zheng, Jiayang Lin and Lanjin Zhang

The purpose of this paper is to experimentally and numerically investigate the interference characteristics between two ski-jump jets on the flip bucket in a large dam…

Abstract

Purpose

The purpose of this paper is to experimentally and numerically investigate the interference characteristics between two ski-jump jets on the flip bucket in a large dam spillway when two floodgates are running.

Design/methodology/approach

The volume of fluid (VOF) method together with the Realizable k-ε turbulence model were used to predict the flow in two ski-jump jets and the free surface motion in a large dam spillway. The movements of the two gates were simulated using a dynamic mesh controlled by a User Defined Function (UDF). The simulations were run using the prototype dam as the field test to minimize errors due to scale effects. The simulation results are compared with field test observations.

Findings

The transient flow calculations, accurately predict the two gate discharges compared to field data with the predicted ski-jump jet interference flow pattern similar to the observed shapes. The transient simulations indicate that the main reason for the deflected nappe is the larger opening difference between the two gates as the buttress side gate closes. When both gates are running, the two ski-jump jets interfere in the flip bucket and raise the jet nappe to near the buttress to form a secondary flow on this jet nappe surface. As the gate continues to close, the nappe surface continues to rise and the surface secondary flow become stronger, which deflects the nappe over the side buttress.

Originality/value

A dynamic mesh is used to simulate the transient flow behavior of two prototype running gates. The transient flow simulation clarifies the hydraulics mechanism for how the two ski-jump jets interfere and deflect the nappe.

Details

Engineering Computations, vol. 32 no. 2
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 4 July 2016

V. Jaiganesh and K. Prakasan

The purpose of this work is to visualize the flow behaviour in critical sections of a pressurized gating system.

Abstract

Purpose

The purpose of this work is to visualize the flow behaviour in critical sections of a pressurized gating system.

Design/methodology/approach

The investigation was carried out using water models of gating system that were designed, invoking the principles of similitude. Water was used as the filling medium, and the manner of flow through various sections of the gating system and the cavity was recorded with a high-speed camera capable of capturing images up to 10,000 frames per second. This was followed by an analysis of the results obtained from each phase. Finally, computer simulations of flow were carried out using commercial software. The manner of filling as observed during experiments and that during simulation were compared so as to draw some useful conclusions on the utility of flow visualization using water models and the capability of software to predict the filling pattern during casting process. It was understood that water models are powerful aids for understanding the intricacies of flow through critical sections of the gating systems.

Findings

It was observed that water models are a reliable indicator of the mould-filling process. Further, substantial differences in the filling pattern were observed between water model experiments and filling simulation using commercial software.

Research limitations/implications

The findings are limited to horizontal plate-type castings. Also, the influence of surface roughness in the flow through the runner is not considered.

Originality/value

This work facilitates understanding of the importance of flow visualization on the quality and reliability of castings.

Details

Journal of Engineering, Design and Technology, vol. 14 no. 3
Type: Research Article
ISSN: 1726-0531

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Article
Publication date: 8 January 2018

Wu Deng, Meng Sun, Huimin Zhao, Bo Li and Chunxiao Wang

This study aims to propose a new airport gate assignment method to effectively improve the comprehensive operation capacity and efficiency of hub airport. Gate assignment…

Abstract

Purpose

This study aims to propose a new airport gate assignment method to effectively improve the comprehensive operation capacity and efficiency of hub airport. Gate assignment is one of the most important tasks for airport ground operations, which assigns appropriate airport gates with high efficiency reasonable arrangement.

Design/methodology/approach

In this paper, on the basis of analyzing the characteristics of airport gates and flights, an efficient multi-objective optimization model of airport gate assignment based on the objectives of the most balanced idle time, the shortest walking distances of passengers and the least number of flights at apron is constructed. Then an improved ant colony optimization (ICQACO) algorithm based on the ant colony collaborative strategy and pheromone update strategy is designed to solve the constructed model to fast realize the gate assignment and obtain a rational and effective gate assignment result for all flights in the different period.

Findings

In the designed ICQACO algorithm, the ant colony collaborative strategy is used to avoid the rapid convergence to the local optimal solution, and the pheromone update strategy is used to quickly increase the pheromone amount, eliminate the interference of the poor path and greatly accelerate the convergence speed.

Practical implications

The actual flight data from Guangzhou Baiyun airport of China is selected to verify the feasibility and effectiveness of the constructed multi-objective optimization model and the designed ICQACO algorithm. The experimental results show that the designed ICQACO algorithm can increase the pheromone amount, accelerate the convergence speed and avoid to fall into the local optimal solution. The constructed multi-objective optimization model can effectively improve the comprehensive operation capacity and efficiency. This study is a very meaningful work for airport gate assignment.

Originality/value

An efficient multi-objective optimization model for hub airport gate assignment problem is proposed in this paper. An improved ant colony optimization algorithm based on ant colony collaborative strategy and the pheromone update strategy is deeply studied to speed up the convergence and avoid to fall into the local optimal solution.

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Book part
Publication date: 12 November 2018

Jason A. Smith

Racism in the United States is complex given the cultural logics that uphold notions of “post-race” or “colorblindness” as a means for understanding racialized events. The…

Abstract

Racism in the United States is complex given the cultural logics that uphold notions of “post-race” or “colorblindness” as a means for understanding racialized events. The various forces at play within media institutions create paradoxes in the power that the media wields in society. Utilizing the concept of “media spectacle” and putting it into dialogue with colorblind racism, the author looks at local coverage of the 2009 arrest of Henry Louis Gates. The author’s primary concern is to identify not only the narratives that uphold or challenge colorblind racism during racialized events, but also the dynamic in which racialized events are mediated in contemporary society. Through a critical discourse analysis of two Boston newspapers, the author demonstrates the way colorblind racism adapts during a racialized event. This study demonstrates the contested nature of the media and nuance to the ways we understand colorblind racism in an increasingly mediated society.

Details

Media and Power in International Contexts: Perspectives on Agency and Identity
Type: Book
ISBN: 978-1-78769-455-2

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Article
Publication date: 23 July 2020

Sandeep Garg and Tarun Kumar Gupta

This paper aims to propose a new fin field-effect transistor (FinFET)-based domino technique low-power series connected foot-driven transistors logic in 32 nm technology…

Abstract

Purpose

This paper aims to propose a new fin field-effect transistor (FinFET)-based domino technique low-power series connected foot-driven transistors logic in 32 nm technology and examine its performance parameters by performing transient analysis.

Design/methodology/approach

In the proposed technique, the leakage current is reduced at footer node by a division of current to improve the performance of the circuit in terms of average power consumption, propagation delay and noise margin. Simulation of existing and proposed techniques are carried out in FinFET and complementary metal-oxide semiconductor technology at FinFET 32 nm technology for 2-, 4-, 8- and 16-input domino OR gates on a supply voltage of 0.9 V using HSPICE.

Findings

The proposed technique shows maximum power reduction of 77.74% in FinFET short gate (SG) mode in comparison with current-mirror-based process variation tolerant (CPVT) technique and maximum delay reduction of 51.34% in low power (LP) mode in comparison with CPVT technique at a frequency of 100 MHz. The unity noise gain of the proposed circuit is 1.10× to 1.54× higher in comparison with different existing techniques in FinFET SG mode and 1.11× to 1.71× higher in FinFET LP mode. The figure of merit of the proposed circuit is up to 15.77× higher in comparison with existing domino techniques.

Originality/value

The research proposes a new FinFET-based domino technique and shows improvement in power, delay, area and noise performance. The proposed design can be used for implementing high-speed digital circuits such as microprocessors and memories.

Details

Circuit World, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0305-6120

Keywords

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