Wenqiang Guo, Yuchen Lu, Ming Lei, Yunze Liang and Jinyan Zhao
To address the various irregularities that occurred during the development of China’s electricity market, particularly the issue of collusive pricing between upstream and…
Abstract
Purpose
To address the various irregularities that occurred during the development of China’s electricity market, particularly the issue of collusive pricing between upstream and downstream firms.
Design/methodology/approach
This study constructs a tripartite evolutionary game model involving government regulators, grid operators and power producers to address electricity market pricing chaos. By analyzing the stable strategies within each subject’s evolutionary game, adjustments to the relevant parameters are made to achieve a stable state of strategy selection.
Findings
The findings of this study indicate the following: (1) Enhancing the government’s rewards and punishments, increasing speculation and rent-seeking costs for grid operators and modifying tariff sales revenue can promote the integrity of grid operators. (2) Establishing reasonable incentives and penalties can effectively mitigate rent-seeking behaviors resulting from collusive pricing in the power industry. (3) Strengthening the accountability of higher authorities to government regulators and adjusting incentives for grid operators to comply and generators to refrain from rent-seeking behavior can increase the likelihood of rigorous inspections by government regulators.
Originality/value
This study elucidates the impact of factors such as the cost of speculation and sales revenue of grid operators, the cost of rent-seeking by power producers and the strength of rewards and punishments by government departments on the power sector. Adjusting these factors can significantly influence the stability of the three-party evolutionary game, providing valuable insights into the regulatory mechanisms of the power industry.
Details
Keywords
Yumei Zhang, Ming Lei, Xiangmin Lan, Xiangyang Zhang, Shenggen Fan and Ji Gao
As one of its major strategies, China has made a new plan to further expand High Standard Farmland (HSF) to all permanent basic farmland (80% of total farmland) for grain security…
Abstract
Purpose
As one of its major strategies, China has made a new plan to further expand High Standard Farmland (HSF) to all permanent basic farmland (80% of total farmland) for grain security over the next decade. Yet, what will be the impact of farmland infrastructure investment on agrifood systems? The paper aims to systematically evaluate the multiple effects (food security, economy, nutrition and environment) of expanding HSF construction under the context of the “Big Food vision” using an interdisciplinary model.
Design/methodology/approach
An interdisciplinary model – AgriFood Systems Model, which links the China CGE model to diet and carbon emission modules, is applied to assess the multiple effects of HSF construction on agrifood systems, such as food security and economic development, residents’ diet quality and carbon emissions. Several policy scenarios are designed to capture these effects of the past HSF investment based on counterfactual analysis and compare the effects of HSF future investment at the national level under the conditions of different land use policies – restricting to grain crops or allowing diversification (like vegetables, and fruit).
Findings
The investments in HSF offer a promising solution for addressing the challenges of food and nutrition security, economic development and environmental sustainability. Without HSF construction, grain production and self-sufficiency would decline significantly, while the agricultural and agrifood systems’ GDP would decrease. The future investment in the HSF construction will further increase both grain production and GDP, improve dietary quality and reduce carbon emissions. Compared with the policy of limiting HSF to planting grains, diversified planting can provide a more profitable economic return, improve dietary quality and reduce carbon emissions.
Originality/value
This study contributes to better informing the impact of land infrastructure expanding investment on the agrifood systems from multiple dimensions based on an interdisciplinary model. We suggest that the government consider applying diversified planting in the future HSF investment to meet nutritional and health demands, increase household income and reduce carbon emissions.
Details
Keywords
Shengqi Guan, Wensen Li, Jie Wang and Ming Lei
The purpose of this paper is to develop a new objective evaluation method of fabric pilling using data-driven visual attention model.
Abstract
Purpose
The purpose of this paper is to develop a new objective evaluation method of fabric pilling using data-driven visual attention model.
Design/methodology/approach
First, the multi-scale filtering images are formed by Gaussian pyramid decomposition. Second, center-surround differences algorithm is used between multi-scale filtering images to build saliency map. On this basis, the pilling information is segmented from saliency map by the segmentation threshold. Finally, the pilling is objectively evaluated by extracting pilling feature. Experimental result shows that compared with the traditional detection methods, the proposed objective evaluation method has strong anti-interference ability, and correct classification rate (CCR) is 96 percent.
Findings
Fabric pilling saliency can be effectively improved by data-driven visual attention model, which will lead to stronger anti-interference ability and higher correct classification rate.
Originality/value
To void uneven illumination, noise, and texture interference, the proposed method can enhance the saliency of small targets in saliency map using a bottom-up visual attention model. Through the threshold segmentation according to pilling feature, the pilling information is effectively from the fabric texture. Pilling feature about pilling area density is extracted to pilling grade evaluation.
Details
Keywords
W.L. Yao and Ming C. Leu
This paper presents a numerical and experimental investigation of ceramic shell cracking during the burnout process in investment casting with internally webbed laser…
Abstract
This paper presents a numerical and experimental investigation of ceramic shell cracking during the burnout process in investment casting with internally webbed laser stereolithography patterns. Considered are the cracking temperature of the ceramic shell, the buckling temperature of the web link, and the glass transition temperature of the epoxy resin. Our hypothesis is that shell cracking will occur if the ceramic rupture temperature is lower than the temperature of glass transition and the temperature of web buckling. This hypothesis is validated by a good agreement we obtained between experimental observations and numerical simulations. It is found that the shell cracking and web link buckling are strongly related to the cross‐sectional dimensions and span length of the web structure and the shell thickness, and that shell cracking can be prevented by buckling of the epoxy webbed pattern in early stages of the burnout process.
Details
Keywords
Frances D. Bryant, Guanghua Sui and Ming C. Leu
Rapid freeze prototyping is a relatively new solid freeform fabrication process, which builds a three‐dimensional part according to a CAD model by depositing and freezing water…
Abstract
Rapid freeze prototyping is a relatively new solid freeform fabrication process, which builds a three‐dimensional part according to a CAD model by depositing and freezing water droplets layer by layer. A study on the effects of RFP process parameters including the nozzle scanning speed, droplet size, and droplet frequency in building ice parts with a single‐nozzle work head is made. Presented in this paper are the results of this study which indicate that these process parameters determine the ice layer thickness and ice line width, which in turn determine the surface roughness and the waiting time required after depositing each layer of water (i.e. between successive layers) during the ice part building process.
Details
Keywords
Tunay Turk, Cesar E. Dominguez, Austin T. Sutton, John D. Bernardin, Jonghyun Park and Ming C. Leu
This paper aims to present spot pattern welding (SPW) as a scanning strategy for laser-foil-printing (LFP) additive manufacturing (AM) in place of the previously used continuous…
Abstract
Purpose
This paper aims to present spot pattern welding (SPW) as a scanning strategy for laser-foil-printing (LFP) additive manufacturing (AM) in place of the previously used continuous pattern welding (CPW) (line-raster scanning). The SPW strategy involves generating a sequence of overlapping spot welds on the metal foil, allowing the laser to form dense and uniform weld beads. This in turn reduces thermal gradients, promotes material consolidation and helps mitigate process-related risks such as thermal cracking, porosity, keyholing and Marangoni effects.
Design/methodology/approach
304L stainless steel (SS) feedstock is used to fabricate test specimens using the LFP system. Imaging techniques are used to examine the melt pool dimensions and layer bonding. In addition, the parts are evaluated for residual stresses, mechanical strength and grain size.
Findings
Compared to CPW, SPW provides a more reliable heating/cooling relationship that is less dependent on part geometry. The overlapping spot welds distribute heat more evenly, minimizing the risk of elevated temperatures during the AM process. In addition, the resulting dense and uniform weld beads contribute to lower residual stresses in the printed part.
Originality/value
To the best of the authors’ knowledge, this is the first study to thoroughly investigate SPW as a scanning strategy using the LFP process. In general, SPW presents a promising strategy for securing embedded sensors into LFP parts while minimizing residual stresses.
Details
Keywords
Chia-Hung Hung, Tunay Turk, M. Hossein Sehhat and Ming C. Leu
This paper aims to present the development and experimental study of a fully automated system using a novel laser additive manufacturing technology called laser foil printing…
Abstract
Purpose
This paper aims to present the development and experimental study of a fully automated system using a novel laser additive manufacturing technology called laser foil printing (LFP), to fabricate metal parts layer by layer. The mechanical properties of parts fabricated with this novel system are compared with those of comparable methodologies to emphasize the suitability of this process.
Design/methodology/approach
Test specimens and parts with different geometries were fabricated from 304L stainless steel foil using an automated LFP system. The dimensions of the fabricated parts were measured, and the mechanical properties of the test specimens were characterized in terms of mechanical strength and elongation.
Findings
The properties of parts fabricated with the automated LFP system were compared with those of parts fabricated with the powder bed fusion additive manufacturing methods. The mechanical strength is higher than those of parts fabricated by the laser powder bed fusion and directed energy deposition technologies.
Originality/value
To the best knowledge of authors, this is the first time a fully automated LFP system has been developed and the properties of its fabricated parts were compared with other additive manufacturing methods for evaluation.
Details
Keywords
Gregory Taylor, Xin Wang, Leah Mason, Ming C. Leu, K. Chandrashekhara, Timothy Schniepp and Ross Jones
The purpose of this paper is to study the flexural behavior of additively manufacture Ultem 1010 parts. Fused deposition modeling (FDM) process has become one of most widely used…
Abstract
Purpose
The purpose of this paper is to study the flexural behavior of additively manufacture Ultem 1010 parts. Fused deposition modeling (FDM) process has become one of most widely used additive manufacturing methods. The process provides the capability of fabricating complicated shapes through the extrusion of plastics onto a print surface in a layer-by-layer structure to build three-dimensional parts. The flexural behavior of FDM parts are critical for the evaluation and optimization of both material and process.
Design/methodology/approach
This study focuses on the performance of FDM solid and sparse-build Ultem 1010 specimens. Flexure tests (three-point bend) are performed on solid-build coupons with varying build orientation and raster angle. These parameters are investigated through a full-factorial design of experiments (DOE) to determine optimal build parameters. Air gap, raster width and contour width are held constant. A three-dimensional nonlinear finite element model is built to simulate the flexural behavior of the FDM parts.
Findings
Experimental results include flexure properties such as yield strength and modulus, as well as analysis of the effect of change in build parameters on material properties. The sparse-build FDM parts chosen from the experimental tests are simulated based on this developed model. Thermo-mechanical simulation results show that the finite element simulation and experimental tests are in good agreement. The simulation can be further extended to other complicated FDM parts.
Originality/value
From the DOE study, sparse-build coupons with specific build parameters are fabricated and tested for the validation of a finite element simulation.
Details
Keywords
Tong-Tong Lin, Ming-Zhi Yang, Lei Zhang, Tian-Tian Wang, Yu Tao and Sha Zhong
The aerodynamic differences between the head car (HC) and tail car (TC) of a high-speed maglev train are significant, resulting in control difficulties and safety challenges in…
Abstract
Purpose
The aerodynamic differences between the head car (HC) and tail car (TC) of a high-speed maglev train are significant, resulting in control difficulties and safety challenges in operation. The arch structure has a significant effect on the improvement of the aerodynamic lift of the HC and TC of the maglev train. Therefore, this study aims to investigate the effect of a streamlined arch structure on the aerodynamic performance of a 600 km/h maglev train.
Design/methodology/approach
Three typical streamlined arch structures for maglev trains are selected, i.e. single-arch, double-arch and triple-arch maglev trains. The vortex structure, pressure of train surface, boundary layer, slipstream and aerodynamic forces of the maglev trains with different arch structures are compared by adopting improved delayed detached eddy simulation numerical calculation method. The effects of the arch structures on the aerodynamic performance of the maglev train are analyzed.
Findings
The dynamic topological structure of the wake flow shows that a change in arch structure can reduce the vortex size in the wake region; the vortex size with double-arch and triple-arch maglev trains is reduced by 15.9% and 23%, respectively, compared with a single-arch maglev train. The peak slipstream decreases with an increase in arch structures; double-arch and triple-arch maglev trains reduce it by 8.89% and 16.67%, respectively, compared with a single-arch maglev train. The aerodynamic force indicates that arch structures improve the lift imbalance between the HC and TC of a maglev train; double-arch and triple-arch maglev trains improve it by 22.4% and 36.8%, respectively, compared to a single-arch maglev train.
Originality/value
This study compares the effects of a streamlined arch structure on a maglev train and its surrounding flow field. The results of the study provide data support for the design and safe operation of high-speed maglev trains.
Details
Keywords
Introduces incentive strategy as a market‐oriented and highly efficient macro‐economy management system (MEMS). By means of the hierarchical decision‐making theory and the…
Abstract
Introduces incentive strategy as a market‐oriented and highly efficient macro‐economy management system (MEMS). By means of the hierarchical decision‐making theory and the stochastic optimization theory, two static models with perfect information structure and partial information structure respectively are designed.