Sushanth Bavirisetti and Mithilesh Kumar Sahu
The purpose of this paper is to analyze the performance of the gas turbine cycle integrated with solid oxide fuel cell technology. In the present work, intermediate temperature…
Abstract
Purpose
The purpose of this paper is to analyze the performance of the gas turbine cycle integrated with solid oxide fuel cell technology. In the present work, intermediate temperature solid oxide fuel cell has been considered, as it is economical, can attain an activation temperature in a quick time, and also have a longer life compared to a high-temperature solid oxide fuel cell, which helps in the commercialization and can generate two ways of electricity as a hybrid configuration.
Design/methodology/approach
The conceptualized cycle has been analyzed with the help of computer code developed in MATLAB with the help of governing equations. In this work, the focus is on the performance investigation of a Gas turbine intermediate temperature solid oxide fuel cell hybrid cycle. The work also analyzes the performance behavior of the proposed cycle with various design and operating parameters.
Findings
It is found that the power generation efficiency of the IT-SOFC-GT hybrid system reaches up to 60% (LHV) for specific design and operating conditions. The cycle calculations of an IT-SOFC-GT hybrid system and its conceptual design have been presented in this work.
Originality/value
The unique feature of this work is that IT-SOFC has been adopted for integration instead of HT-SOFC, and this work also provides the performance behavior of the hybrid system with varying design and operating parameters, which is the novelty of this work. This work has significant scientific merit, as the cost involved for the commercialization of IT-SOFC is comparatively lower than HT-SOFC and provides a good option to energy manufacturers for generating clean energy at a low cost.
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The purpose of this paper is to present an up-to-date survey on the non-orthogonal multiple access (NOMA) technique with co-operative strategy, a fast-evolving fifth-generation…
Abstract
Purpose
The purpose of this paper is to present an up-to-date survey on the non-orthogonal multiple access (NOMA) technique with co-operative strategy, a fast-evolving fifth-generation (5 G) technology. NOMA is used for serving many mobile users, both in power and code domains. This paper considers the power-domain NOMA, which is now discussed as NOMA.
Design/methodology/approach
The first part of the paper discusses NOMA-based cooperative relay systems using different relay strategies over different channel models. In various research works, the analytical expressions of many performance metrics were derived, measured and simulated for better performance of the NOMA systems. In the second part, a brief introduction to diversity techniques is discussed. The multiple input and multiple output system merged with cooperative NOMA technology, and its future challenges were also presented in this part. In the third part, the paper surveys some new conceptions such as cognitive radio, index modulation multiple access, space-shift keying and reconfigurable intelligent surface that can be combined with NOMA systems for better performance.
Findings
The paper presents a brief survey of diverse research projects being carried out in the field of NOMA. The paper also surveyed two different relaying strategies that were implemented in cooperative NOMA over different channels and compared several performance parameters that were evaluated and derived in these implementations.
Originality/value
The paper provides a scope for recognizable future work and presents a brief idea of the new techniques that can be united with NOMA for better performance in wireless systems.
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Jintao Zhan, Yubei Ma, Xinye Lv, Meng Xu and Mingyang Zhang
Some researchers argue that consumers’ lack of knowledge is an important factor increasing risk for a new product derived from emerging agricultural technology. The purpose of…
Abstract
Purpose
Some researchers argue that consumers’ lack of knowledge is an important factor increasing risk for a new product derived from emerging agricultural technology. The purpose of this paper is to discuss the potential impacts and the differential effects of subjective and objective perceptions on Chinese consumers’ preferences for the application of a novel biotechnology.
Design/methodology/approach
Taking transgenic technology as an example and employing data from a survey of 1,000 consumers in Jiangsu Province, the authors develop a mixed-process regression model based on Fishbein’s multiple attributes attitude model.
Findings
The results suggest that there are apparent differences between Chinese consumers’ subjective perceptions and objective perceptions concerning transgenic technology and genetically modified (GM) food, and there exists certain selective perceptions of the emerging biotechnology. Having a subjective perception concerning transgenic technology has a positive effect on consumers’ overall attitudes, whereas subjective and objective perceptions concerning GM foods have a negative effect on consumers’ overall attitudes. Self-identification generated from subjective perception occupies a dominant position in determining consumers’ attitudes.
Originality/value
Consumers’ attitudes regarding an agricultural product depend on their perception of the attributes of the technology used to produce such a product. This study attempts to distinguish and empirically test urban consumers’ subjective perceptions (self-assessed or perceived) and objective perceptions (obtained from a test) about transgenic technology and GM foods and the impact of these four types of perception on the consumers’ attitudes regarding the application of transgenic technology. In this paper, the authors construct a mixed-process regression model to address the possible endogeneity of the perception variables.
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Sun Jingchun, Lv Ding and Wu Fan
The purpose of this paper is to model the trend of natural gas supply and demand in China in different circumstances from 1990 to 2050.
Abstract
Purpose
The purpose of this paper is to model the trend of natural gas supply and demand in China in different circumstances from 1990 to 2050.
Design/methodology/approach
The related factors were selected from references and classified into three categories such as endogenous, exogenous, and excluded factors. The three sub‐models of supply, demand and their interconnection were built and integrated. The impacts of natural gas resources, the investment of gas industry and the energy structure over natural gas supply and demand were analyzed based on scenario analysis.
Findings
The impact of energy structure in China is more evident compared to natural gas resources and the investment level.
Research limitations/implications
Import and transportation of natural gas will have growing impacts on the supply and demand in China when the model is applied.
Practical implications
A very useful method to analyze the equilibrium of natural gas supply and demand.
Originality/value
The paper presents a new prediction model of natural gas supply and demand in system dynamics. The paper is aimed at the researchers and decision makers in energy industries, especially in the fields of energy prices.
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Ying Lv, Jinlong Feng, Guangbin Wang and Hua Li
This study aims to improve the maneuverability and stability of four-wheel chassis in a small paddy field; a front axle swing steering four-wheel chassis with optimal steering is…
Abstract
Purpose
This study aims to improve the maneuverability and stability of four-wheel chassis in a small paddy field; a front axle swing steering four-wheel chassis with optimal steering is designed.
Design/methodology/approach
When turning, the front inner wheel stops and the rear inner wheel is in the following state. The hydraulic drive system of the walking wheel adopts a driving mode in which two front-wheel motors are connected in series and two rear wheel motors in parallel. The chassis uses a combination of a gasoline engine with a water cooling system, a CVT continuously variable transmission and a hydraulic drive system to increase the control capability. The front axle rotary chassis adopts a step-less variable speed engine and a hydraulic control system to solve the hydraulic stability of the chassis in uphill and downhill conditions so as to effectively control the over-speed of the wheel-side drive motors. Through the quadratic orthogonal rotation combination design test, the mathematical models of uphill and downhill front-wheel pressures and test factors are established.
Findings
The results show that the chassis stability is optimal when the back pressure is 0.5 MPa, and the rotating slope is 4°. The uphill and downhill pressures of the front wheels are 2.38 MPa and 1.5 MPa, respectively.
Originality/value
The influence of external changes on the pressure of hydraulic motors is studied through experiments, which lays the foundation for further research.
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Lichao Wang, Fuyan Ding, Dongbo Yang, Ke Wang, Biaoqiang Jiao and Qian Chen
This paper aims to provide a new method of generating relatively accurate and smooth saturated B-H curves based on reliable measurement data to improve the accuracy and efficiency…
Abstract
Purpose
This paper aims to provide a new method of generating relatively accurate and smooth saturated B-H curves based on reliable measurement data to improve the accuracy and efficiency of electromagnetic simulation.
Design/methodology/approach
The characteristics of different B-H curve extrapolation models are summarized, and an improved method is proposed. The fitting procedure in low fields and extrapolation procedure in high fields are presented in detail. The saturated B-H curves generated by various methods are compared and discussed. Finally, a simulation case study proved the advantages of the new method in terms of simulation accuracy and efficiency.
Findings
The B-H curve created by the new method avoids extrapolation from a single point and simultaneously smoothens the entire B-H curve, thereby improving the simulation accuracy and efficiency. The low magnetic potential requirements for closed measurements and the small deviation with open measurements indicate that this method is well-suited for implementation.
Research limitations/implications
The results are applicable for materials subject to such excitation levels that saturation has to be taken into account.
Originality/value
While some extrapolation models of B-H curves have been investigated in reference papers, there is still room for improvement in accuracy and smoothness. The new method processes low fields and high fields magnetization data and then connects them based on third-order boundary equations for the first time. This method can generate saturated B-H curves with good accuracy and smoothness while retaining outstanding operability.
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Ali Baqaei, Ali Asghar Sabbagh Alvani and Hassan Sameie
Over the past decades, intense efforts have been devoted to design and synthesize efficient photocatalysts which are active under sunlight for environmental and energy…
Abstract
Purpose
Over the past decades, intense efforts have been devoted to design and synthesize efficient photocatalysts which are active under sunlight for environmental and energy applications. Titanium dioxide (TiO2) has attracted much attention over many years for organic contaminant degradation in air or water due to its strong optical absorptivity, chemical stability and low cost. However, TiO2 has a very low photo quantum yield which prompts the easy recombination of photogeneration electron/hole pairs. In addition, bandgap of 3.2 eV restrains application of this photocatalyst mainly to the UV range.
Design/methodology/approach
Vertically oriented one-dimensional TiO2 nanostructures remarkably improve electron transport by creating a direct conduction pathway, decreasing intercrystalline contacts and stretching grown structure with the specified directionality. In this research, to enhance the visible light absorbance of TiO2, prearranged hydrogenated titanium dioxide nanorods (H-TNRs) in the presence of H2/N2 gas flow are hydrothermally synthesized.
Findings
The X-ray diffraction patterns illustrated the characteristic peaks of tetragonal rutile TiO2 and confirmed that there is no phase change after hydrogenation. Trivalent titanium ions surface defects and oxygen vacancies were considered as major reasons for redshift of absorption edge toward visible region and subsequently narrowing the bandgap to 2.27 eV. The optimized photocatalysts exhibited high visible-light-driven photocatalytic activity for degradation of methylene blue in water within 210. The synthesized H-TNRs established themselves as promising photocatalysts for organic compounds degradation in the aqueous solution.
Originality/value
To the best of the authors’ knowledge, this work is original and has not been published elsewhere nor is it currently under consideration for publication elsewhere.
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Zhong Wu, Qing Hu, Zhenbo Qin, Yiwen Zhang, Da-Hai Xia and Wenbin Hu
Nickel-aluminum bronze (NAB) has been widely used in ship propellers. It is always subjected to local micro-plastic deformation in service environments. This paper aims to study…
Abstract
Purpose
Nickel-aluminum bronze (NAB) has been widely used in ship propellers. It is always subjected to local micro-plastic deformation in service environments. This paper aims to study the influence of plastic deformation on the mechanical strength and corrosion resistance of NAB in 3.5 Wt.% NaCl solution.
Design/methodology/approach
Scanning electron microscope and X-ray diffraction were used to analyze the microstructure of NAB alloy with different plastic deformations. Mechanical properties of the sample were measured by tensile experiment, and corrosion behavior was studied by electrochemical measurements and the long-term immersion corrosion test.
Findings
Results showed that the plastic deformation caused lattice distortion but did not change the microstructure of NAB alloy. Microhardness and yield strength of NAB were significantly improved with the increase of deformation. The lattice distortion accelerated the formation of corrosion product film, which made the deformed alloy show a more positive open-circuit potential and an increased Rp. However, during the long-term immersion corrosion, the corrosion resistance of NAB alloys deteriorated with the increase of plastic deformation. This is because larger plastic deformation brought about higher internal stress in corrosion product film, which resulted in the premature peeling of the film and the loss of its protective effect on the alloy substrate.
Originality/value
Tensile plastic deformations were found to cause a decline in the corrosion resistance of NAB. And the mechanism was clarified from the evolution of corrosion products during the corrosion process.
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Longfei Song, Zhiyong Liu, Lin Lu, Xiaogang Li, BaoZhuang Sun and Huanlin Cheng
This paper aims to analyze a failure case of a P110 tube in a CO2 flooding well.
Abstract
Purpose
This paper aims to analyze a failure case of a P110 tube in a CO2 flooding well.
Design/methodology/approach
The chemical composition, microstructure and mechanical properties of the failed P110 tubing steel were tested, and met the API Spec 5CT standard. The fractures were investigated by scanning electron microscopy and energy dispersive spectroscopy.
Findings
Fracture was induced by stress corrosion cracking (SCC) and that the stress concentration caused by the mechanical damage played an important role in the failure. The failure case is a SCC failure affected by mechanical damage and galvanic corrosion.
Originality/value
The effect of the infiltration of groundwater was studied in the failure case. The stress concentration caused by the mechanical damage played an important role in the failure.
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Christopher M. Castille and Larry J. Williams
In this chapter, the authors critically examine the application of unmeasured latent method factors (ULMFs) in human resource and organizational behavior (HROB) research, focusing…
Abstract
In this chapter, the authors critically examine the application of unmeasured latent method factors (ULMFs) in human resource and organizational behavior (HROB) research, focusing on addressing common method variance (CMV). The authors explore the development and usage of ULMF to mitigate CMV and highlight key debates concerning measurement error in the HROB literature. The authors also discuss the implications of biased effect sizes and how such bias can lead HR professionals to oversell interventions. The authors provide evidence supporting the effectiveness of ULMF when a specific assumption is held: a single latent method factor contributes to the data. However, the authors dispute this assumption, noting that CMV is likely multidimensional; that is, it is complex and difficult to fix with statistical methods alone. Importantly, the authors highlight the significance of maintaining a multidimensional view of CMV, challenging the simplification of a CMV as a single source. The authors close by offering recommendations for using ULMFs in practice as well as more research into more complex forms of CMV.