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Article
Publication date: 12 March 2018

Jiang Chen, Junli Zheng and Feng Xiong

The spatial resolution of seepage monitoring methods based on fiber Bragg grating (FBG) temperature sensing technology is limited by the distance between measurement…

Abstract

Purpose

The spatial resolution of seepage monitoring methods based on fiber Bragg grating (FBG) temperature sensing technology is limited by the distance between measurement points. Improving the spatial resolution for a given number of measurement points is a prerequisite for popularizing this technology in the seepage monitoring of rockfill dams. The purpose of this paper is to address this problem.

Design/methodology/approach

This paper proposes a mobile-distributed seepage monitoring method based on the FBG-hydrothermal cycling seepage monitoring system. In this method, the positions of the measurement points are changed by freely dragging the FBG sensing cluster within the inner tube of a dual-tube structure, consisting of an inner polytetrafluoroethylene tube and outer polyethylene of raised temperature resistance heating tube.

Findings

A seepage velocity calibration test was carried out using the improved monitoring system. The results showed that under a constant seepage velocity, the use of the dual-tube structure enables faster cooling, and the cooling rate accelerates with an increase in the diameter of the inner tube. The use of the dual-tube structure can improve the sensitivity of the seepage evaluation index ζv to the seepage velocity. When the inner diameter increases, ζv becomes more sensitive to the seepage velocity.

Originality/value

A mobile-distributed seepage monitoring method based on FBG sensing technology is proposed in which the FBG sensors are not fixed. Instead, the positions of the measurement points are changed to improve the spatial resolution. Meanwhile, the use of the dual-tube structure in the presented monitoring system can improve its sensitivity.

Details

Sensor Review, vol. 38 no. 3
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 11 February 2021

Mingyang Liu, Huifen Zhu, Guangjun Gao, Chen Jiang and G.R Liu

The purpose of this paper is to investigate a novel stabilization scheme to handle convection and pressure oscillation in the process of solving incompressible laminar…

Abstract

Purpose

The purpose of this paper is to investigate a novel stabilization scheme to handle convection and pressure oscillation in the process of solving incompressible laminar flows by finite element method (FEM).

Design/methodology/approach

The semi-implicit stabilization scheme, characteristic-based polynomial pressure projection (CBP3) consists of the Characteristic-Galerkin method and polynomial pressure projection. Theoretically, the proposed scheme works for any type of element using equal-order approximation for velocity and pressure. In this work, linear 3-node triangular and 4-node tetrahedral elements are the focus, which are the simplest but most difficult elements for pressure stabilizations.

Findings

The present paper proposes a new scheme, which can stabilize FEM solution for flows of both low and relatively high Reynolds numbers. And the influence of stabilization parameters of the CBP3 scheme has also been investigated.

Research limitations/implications

The research in this work is limited to the laminar incompressible flow.

Practical implications

The verification and validation of the CBP3 scheme are conducted by several 2 D and 3 D numerical examples. The scheme could be used to deal with more practical fluid problems.

Social implications

The application of scheme to study complex hemodynamics of patient-specific abdominal aortic aneurysm is also presented, which demonstrates its potential to solve bio-flows.

Originality/value

The paper simulated 2 D and 3 D numerical examples with superior results compared to existing results and experiments. The novel CBP3 scheme is verified to be very effective in handling convection and pressure oscillation.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 5
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 2 May 2017

Lei Chen and Jiang Chen

This paper aims to conduct the optimization of the multi-stage gas turbine with the effect of the cooling air injection based on the adjoint method.

Abstract

Purpose

This paper aims to conduct the optimization of the multi-stage gas turbine with the effect of the cooling air injection based on the adjoint method.

Design/methodology/approach

Continuous adjoint method is combined with the S2 surface code.

Findings

The optimization of the stagger angles, stacking lines and the passage can improve the attack angles and restrain the development of the boundary, reducing the secondary flow loss caused by the cooling air injection.

Practical implications

The aerodynamic performance of the gas turbine can be improved via the optimization of blade and passage based on the adjoint method.

Originality/value

The results of the first study on the adjoint method applied to the S2 surface through flow calculation including the cooling air effect are presented.

Details

Aircraft Engineering and Aerospace Technology, vol. 89 no. 3
Type: Research Article
ISSN: 1748-8842

Keywords

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Article
Publication date: 4 July 2016

Lihong Gao, Jiang Chen, Jun Zheng and Haiyan Zhang

The purpose of the study reported in this paper is to synthesis curcumin, which was reported to possess broad pharmacological effects and excellent dyeing properties, via…

Abstract

Purpose

The purpose of the study reported in this paper is to synthesis curcumin, which was reported to possess broad pharmacological effects and excellent dyeing properties, via Claisen-Schmidt condensation reaction catalysed by an efficient and green solid base catalyst, KF/Al2O3.

Design/methodology/approach

A series of catalysts with different KF loadings and varying calcination temperatures had been prepared, characterised by Brunauer–Emmett–Taller surface area, temperature-programmed desorption with CO2 using infrared spectroscopy, X-ray powder diffraction and X-ray photoelectron spectroscopy, and tested in the Claisen–Schmidt condensation reaction. The effects of different reaction parameters such as temperature, the amount of catalyst, reactant ratio and time on the synthesis of curcumin were examined. The possibility of recycling the catalyst was also investigated in detail. Moreover, the reaction mechanism and the role of KF/Al2O3 in the synthetic process were discussed.

Findings

The study provides an efficient and green solid base catalyst, KF/Al2O3, and 64.3 per cent yield of curcumin was obtained under the optimum reaction conditions. Experimental results indicate that the third reused catalyst could retain part of the catalytic activity, and the regenerated one could be reused with reasonable catalytic activity. Besides, K3AlF6 was proposed as the active site of the catalyst for the reaction by the analysis of the characterization results of KF/Al2O3.

Originality/value

KF/Al2O3 was found to be an efficient catalyst for catalytic synthesis of curcumin and could be easily recycled several times. This information may be useful for further research and practical applications of curcumin.

Details

Pigment & Resin Technology, vol. 45 no. 4
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 8 July 2019

Zaihao Tian, Jin-Kui Ma, Lu Changhou and Shu-Jiang Chen

The purpose of this paper is to maximize the load-carrying capacity (LCC) of a rotating ring, a numerical model optimizing both the surface and bottom shape of its surface…

Abstract

Purpose

The purpose of this paper is to maximize the load-carrying capacity (LCC) of a rotating ring, a numerical model optimizing both the surface and bottom shape of its surface textures is proposed.

Design/methodology/approach

The Reynolds equation is used to evaluate the film pressure and LCC obtained by integrating the film pressure is set as the objective function. Around the center of the computational domain, radial lines with an equal angle between adjacent ones are produced and the surface contour of textures is obtained by connecting the endpoints using a spline curve. The bottom profile is then obtained by connecting the endpoints of two vertical lines at the circumferential ends of textures. Lengths of these lines are set as design variables and genetic algorithm is used to solve optimization models.

Findings

Results show that optimum textures have an “apple-like” surface contour and a “wedge-like” bottom profile, which are both expressed by smooth spline curves. Optimum wedge-bottom textures generate higher LCC than optimum flat-bottom textures. Moreover, the optimum textures have the highest LCC compared with optimum grooves proposed previously, which validates the practical value of the current optimization model.

Originality/value

This work presents a comprehensive optimization method of texture geometry, which provides a new idea of the design of surface textures.

Details

Industrial Lubrication and Tribology, vol. 71 no. 5
Type: Research Article
ISSN: 0036-8792

Keywords

Content available
Article
Publication date: 3 February 2020

Hangjing Zhang, Yan Chen and H. Vicky Zhao

The purpose of this paper is to have a review on the analysis of information diffusion based on evolutionary game theory. People now get used to interact over social…

Abstract

Purpose

The purpose of this paper is to have a review on the analysis of information diffusion based on evolutionary game theory. People now get used to interact over social networks, and one of the most important functions of social networks is information sharing. Understanding the mechanisms of the information diffusion over social networks is critical to various applications including online advertisement and rumor control.

Design/methodology/approach

It has been shown that the graphical evolutionary game theory (EGT) is a very efficient method to study this problem.

Findings

By applying EGT to information diffusion, the authors could predict every small change in the process, get the detailed dynamics and finally foretell the stable states.

Originality/value

In this paper, the authors provide a general review on the evolutionary game-theoretic framework for information diffusion over social network by summarizing the results and conclusions of works using graphical EGT.

Details

International Journal of Crowd Science, vol. 4 no. 1
Type: Research Article
ISSN: 2398-7294

Keywords

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Article
Publication date: 19 March 2021

Changwu Liu, Haowen Wang and Chen Jiang

The paper aims at developing a novel algorithm to estimate high-order derivatives of rotorcraft angular rates to break the contradiction between bandwidth and filtering…

Abstract

Purpose

The paper aims at developing a novel algorithm to estimate high-order derivatives of rotorcraft angular rates to break the contradiction between bandwidth and filtering performance because high-order derivatives of angular rates are crucial to rotorcraft control. Traditional causal estimation algorithms such as digital differential filtering or various tracking differentiators cannot balance phase-lead angle loss and high-frequency attenuation performance of the estimated differentials under the circumstance of strong vibration from the rotor system and the rather low update rate of angular rates.

Design/methodology/approach

The algorithm, capable of estimating angular rate derivatives to maximal second order, fuses multiple attitude signal sources through a first-proposed randomized angular motion maneuvering model independent of platform dynamics with observations generated by cascaded tracking differentiators.

Findings

The maneuvering flight test on 5-kg-level helicopter and the ferry flight test on 230-kg-level helicopter prove such algorithm is feasible to generate higher signal to noise ratio derivative estimation of angular rates than traditional differentiators in regular flight states with enough bandwidth for flight control.

Research limitations/implications

The decrease of update rate of input attitude signals will weaken the bandwidth performance of the algorithm and higher sampling rate setting is recommended.

Practical implications

Rotorcraft flight control researchers and engineers would benefit from the estimation method when implementing flight control laws requiring angular rate derivatives.

Originality/value

A purely kinematic randomized angular motion model for flight vehicle is first established, combining rigid-body Euler kinematics. Such fusion algorithm with observations generated by cascaded tracking differentiators to estimate angular rate derivatives is first proposed, realized and flight tested.

Details

Aircraft Engineering and Aerospace Technology, vol. 93 no. 2
Type: Research Article
ISSN: 1748-8842

Keywords

Content available
Article
Publication date: 19 November 2018

Benliu Qiu and Ningxuan Zhang

With the recent development of science and technology, research on information diffusion has become increasingly important.

Abstract

Purpose

With the recent development of science and technology, research on information diffusion has become increasingly important.

Design/methodology/approach

To analyze the process of information diffusion, researchers have proposed a framework with graphical evolutionary game theory (EGT) according to the theory of biological evolution.

Findings

Through this method, one can study and even predict information diffusion.

Originality/value

This paper summarizes three existing works using graphical EGT to discuss how to obtain the static state and the dynamics of information diffusion in social network.

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Article
Publication date: 9 May 2016

Wen Jiang and Xu Chen

The purpose of this paper is to investigate the manufacturer’s production, pricing and green technology investment decision problem when strategic customer behavior and…

Abstract

Purpose

The purpose of this paper is to investigate the manufacturer’s production, pricing and green technology investment decision problem when strategic customer behavior and carbon emissions-sensitive random demand is taken into consideration and discuss the impact of carbon emissions-sensitive demand on the manufacturer’s operation strategies, total carbon emissions and maximum expected profit.

Design/methodology/approach

The authors formulate a model to introduce carbon emissions-sensitive demand into the newsvendor framework with strategic customer behavior. The authors characterize the rational expectations equilibrium to derive the optimal solutions to the manufacturer. The authors analyze the effects of carbon emissions-sensitive demand on the manufacturer’s optimal strategies, total carbon emissions and maximum expected profit by comparative analysis.

Findings

The authors obtain the manufacturer’s optimal production, pricing and green technology investment strategies under rational expectations equilibrium in scenario of price-sensitive demand and that of carbon emissions-sensitive demand, respectively. The authors find that as customer demand changes from price-sensitive demand to carbon emissions-sensitive demand, the manufacturer’s optimal prices are the same but optimal production quantity, optimal unit carbon emissions and maximum expected profit go down. Though the total emissions decrease, the carbon emissions reduction would not increase as the demand is more carbon emissions-sensitive. Whether it increases or decreases depends on the model parameters.

Originality/value

Carbon emissions-sensitive demand and strategic customer behavior are considered simultaneously in an integrated model. The result can guide the manufacturer decision-making. The proposed model are hoped to shed light to the future works in the field of sustainable supply chain management.

Details

Industrial Management & Data Systems, vol. 116 no. 4
Type: Research Article
ISSN: 0263-5577

Keywords

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Book part
Publication date: 7 May 2019

Higinio Mora, Francisco A. Pujol López, Julio César Mendoza Tello and Mario R. Morales

Virtual currency is a digital representation of value that is neither issued by a central bank or a public authority. Its reliability is based on advanced cryptographic…

Abstract

Virtual currency is a digital representation of value that is neither issued by a central bank or a public authority. Its reliability is based on advanced cryptographic methods which provide privacy and confidence to citizens. Virtual currency and its underlying technologies such as blockchain or smart contracts trigger transformation in many areas of the society’s functioning. The way in which social relations occur and economic transactions are managed are changing forever. As a result, cryptocurrencies constitute a good example of how specific technology may lead to substantial transformation of the world. Still, virtual currencies could benefit from the versatility of collaborative communication of social media and Internet to promote and develop new commerce and business initiatives as well as new forms of financial flow managements. The objective of this chapter is to examine the role played by virtual currencies in modern societies in order to describe potential uses and applications and their impact on politics and social behavior. As a result, recommendations are inferred to address the challenges and opportunities of these new technologies.

Details

Politics and Technology in the Post-Truth Era
Type: Book
ISBN: 978-1-78756-984-3

Keywords

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