Xiongfeng Zhu, Zheng Guo, Zhongxi Hou, Xianzhong Gao and Juntao Zhang
The purpose of this study is to present a methodology for parameters’ sensitivity analysis of solar-powered airplanes.
Abstract
Purpose
The purpose of this study is to present a methodology for parameters’ sensitivity analysis of solar-powered airplanes.
Design/methodology/approach
The study focuses on a preliminary design and parameters’ relations of a heavier-than-air, solar-powered, high-altitude long-endurance unmanned aerial vehicle. The methodology is founded on the balance of energy production and requirement. An analytic expression with four generalized parameters is derived to determine the airplane flying on the specific altitude. The four generalized parameters’ sensitivities on altitude are then analyzed. Finally, to demonstrate the methodology, a case study is given on the parameters’ sensitivity analysis of a prototype solar-powered airplane.
Findings
When using the presented methodology, the nighttime duration and the energy density of batteries are more sensitive on flight altitude of the prototype airplane.
Practical implications
It is not easy to design a solar-powered airplane to realize high-attitude and long-endurance flight. For the current state-of-art, it is a way to figure out the most critical parameters which need prior consideration and immediate development.
Originality/value
This paper provides an analytical methodology for analyzing the parameters’ sensitivities of solar-powered airplanes, which can benefit the preliminary design of a solar-powered airplane.
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Keywords
Minyan Wei, Juntao Zheng, Shouzhen Zeng and Yun Jin
The main aim of this paper is to establish a reasonable and scientific evaluation index system to assess the high quality and full employment (HQaFE).
Abstract
Purpose
The main aim of this paper is to establish a reasonable and scientific evaluation index system to assess the high quality and full employment (HQaFE).
Design/methodology/approach
This paper uses a novel Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) multi-criteria framework to evaluate the quality and quantity of employment, wherein the integrated weights of attributes are determined by the combined the Criteria Importance Through Inter-criteria Correlation (CRITIC) and entropy approaches.
Findings
Firstly, the gap in the Yangtze River Delta in employment quality is narrowing year by year; secondly, employment skills as well as employment supply and demand are the primary indicators that determine the HQaFE; finally, the evaluation scores are clearly hierarchical, in the order of Shanghai, Jiangsu, Zhejiang and Anhui.
Originality/value
A scientific and reasonable evaluation index system is constructed. A novel CRITIC-entropy-TOPSIS evaluation is proposed to make the results more objective. Some policy recommendations that can promote the achievement of HQaFE are proposed.
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Zhenhua Luo, Juntao Guo, Jianqiang Han and Yuhong Wang
Prefabricated technology is gradually being applied to the construction of subway stations due to its characteristic of mechanization. However, the prefabricated subway station in…
Abstract
Purpose
Prefabricated technology is gradually being applied to the construction of subway stations due to its characteristic of mechanization. However, the prefabricated subway station in China is in the initial stage of development, which is prone to construction safety issues. This study aims to evaluate the construction safety risks of prefabricated subway stations in China and formulate corresponding countermeasures to ensure construction safety.
Design/methodology/approach
A construction safety risk evaluation index system for the prefabricated subway station was established through literature research and the Delphi method. Furthermore, based on the structure entropy weight method, matter-element theory and evidence theory, a hybrid evaluation model is developed to evaluate the construction safety risks of prefabricated subway stations. The basic probability assignment (BPA) function is obtained using the matter-element theory, the index weight is calculated using the structure entropy weight method to modify the BPA function and the risk evaluation level is determined using the evidence theory. Finally, the reliability and applicability of the evaluation model are verified with a case study of a prefabricated subway station project in China.
Findings
The results indicate that the level of construction safety risks in the prefabricated subway station project is relatively low. Man risk, machine risk and method risk are the key factors affecting the overall risk of the project. The evaluation results of the first-level indexes are discussed, and targeted countermeasures are proposed. Therefore, management personnel can deeply understand the construction safety risks of prefabricated subway stations.
Originality/value
This research fills the research gap in the field of construction safety risk assessment of prefabricated subway stations. The methods for construction safety risk assessment are summarized to establish a reliable hybrid evaluation model, laying the foundation for future research. Moreover, the construction safety risk evaluation index system for prefabricated subway stations is proposed, which can be adopted to guide construction safety management.
Details
Keywords
Jie Zhang, Jing Liu, Qian Hu, Feng Huang, ZhaoYang Cheng and JunTao Guo
The aim of this paper was to clarify the influence of tensile stress on the electrochemical behavior of X80 steel in a simulated acid soil solution and attempt to understand…
Abstract
Purpose
The aim of this paper was to clarify the influence of tensile stress on the electrochemical behavior of X80 steel in a simulated acid soil solution and attempt to understand mechanistic aspects of the corrosion behaviors of X80 under these conditions.
Design/methodology/approach
The electrochemical behavior of X80 steel at various tensile stresses was investigated in a simulated acid soil solution using electrochemical impedance spectroscopy, potentiodynamic scan measurements and surface analysis techniques.
Findings
The results show that as tensile stress was increased, the open-circuit potential decreased, the reaction activity increase, the reaction resistance (Rct)value became smaller by degrees, the corrosion product film resistance (Rf) first decreased and then increased and polarization current densities changed conversely. The corrosion product film was compact and continuous under the low stress, whereas it was relatively loose under high-stress conditions. Tensile stress promotes the movement of dislocations, which become active points when they move to the steel surface. The increase in the number of active points enhances the anodic dissolution rate and promotes the formation of corrosion product film whose blocking effect can decrease the dissolution rate. The corrosion rate of the specimen is determined by these two effects.
Originality/value
This research provides an essential insight into the mechanism of the electrochemical behavior of X80 steel in acid soil environments.
Details
Keywords
Hamdan Mohammed Al-Sabri, Majed Al-Mashari and Azeddine Chikh
The purpose of this paper is to consider the question of what is an appropriate enterprise resource planning (ERP) reference model for specifying areas of change in the context of…
Abstract
Purpose
The purpose of this paper is to consider the question of what is an appropriate enterprise resource planning (ERP) reference model for specifying areas of change in the context of IT-driven ERP implementation and through the model matching. There are other implicit goals to increasing the awareness of the reference models, as this highlights the principles embedded in ERP systems and explains the classification of reference models, which is useful in terms of the reuse of knowledge.
Design/methodology/approach
In this paper, a comparison between ERP reference models is conducted using a suitable decision-making technique and the final results are discussed. The comparison depends on nine criteria related to conceptual ERP reference models: scope, abstraction, granularity, views, purpose, simplicity, availability, ease of use for model matching, and target audience.
Findings
This study concludes that the business process reference model is best for specifying areas of change in the context of IT-driven ERP implementations. The final ranking of the alternatives based on all criteria places the system organizational model second, followed by the function and data/object reference models, in that order.
Originality/value
This paper is one of very few studies on the selection of appropriate ERP reference models according to the ERP implementation approach and model matching factors. This research also provides an in-depth analysis of various ERP reference model types.
Details
Keywords
Wenchao Zhang, Enming Cui, Cheng Wang, Baoquan Zhang, Jiwei Jin, Pengfei Zhang, Wending Wu and Mingwei Wang
An investigation was conducted into the impact of various process parameters on the surface and subsurface quality of glass-ceramic materials, as well as the mechanism of material…
Abstract
Purpose
An investigation was conducted into the impact of various process parameters on the surface and subsurface quality of glass-ceramic materials, as well as the mechanism of material removal and crack formation, through the use of ultrasonic-assisted grinding.
Design/methodology/approach
A mathematical model of crack propagation in ultrasonic-assisted grinding was established, and the mechanism of crack formation was described through the model. A series of simulations and experiments were conducted to investigate the impact of process parameters on crack depth, surface roughness, and surface topography during ultrasonic-assisted surface and axial grinding. Additionally, the mechanism of crack formation was explored.
Findings
During ultrasonic-assisted grinding, the average grinding forces are between 0.4–1.0 N, which is much smaller than that of ordinary grinding (1.0–3.5 N). In surface grinding, the maximum surface stresses between the workpiece and the tool gradually decrease with the tool speed. The surface stresses of the workpiece increase with the grinding depth, and the depth of subsurface cracks increases with the grinding depth. With the increase of the axial grinding speed, the subsurface damage depth increases. The roughness increases from 0.780um/1.433um.
Originality/value
A mathematical model of crack propagation in ultrasonic-assisted grinding was established, and the mechanism of crack formation was described through the model. The deformation involved in the grinding process is large, and the FEM-SPH modeling method is used to solve the problem that the results of the traditional finite element method are not convergent and the calculation efficiency is low.
Details
Keywords
Md. Helal Miah, Jianhua Zhang and Ravinder Tonk
Regarding the assembly of the fuselage panel, this paper aims to illustrate a design of pre-assembly tooling of the fuselage panel for the automatic drilling riveting machine…
Abstract
Purpose
Regarding the assembly of the fuselage panel, this paper aims to illustrate a design of pre-assembly tooling of the fuselage panel for the automatic drilling riveting machine. This new prototype of pre-assembly tooling can be used for different types and sizes of fuselage panels. Also, apply to the automated drilling and riveting machine of the fuselage panels.
Design/methodology/approach
Based on the different structures of the fuselage panel, the position of the preassembly tooling components, location of the clamp and position of the fuselage panel are determined. After that, the overall structure of the preassembly tooling is designed, including the movable frame and the cardboard. The cardboard positioning module and the clamping module formulate a detailed design scheme of preassembly tooling for the fuselage panel. The structure of the pre-assembled tooling is optimized by static analysis. The result of the overall design is optimized by using MATLAB and CATIA-V5 software, and the results meet the condition of the design requirements.
Findings
The traditional assembly process of the fuselage is to install the fuselage panel on the preassembly tooling for positioning the hole and then install it on the automated drilling and riveting tooling for secondary tooling. Secondary tooling can consume assembly errors of the fuselage panel. The new prototype of flexible tooling design for the fuselage panel not only avoids the secondary tooling error of the fuselage panel but also meets the preassembly of different types of fuselage panels.
Research limitations/implications
The further development of the flexible tooling design of the fuselage panel is to reduce the error of sliding tooling due to friction of the sliding components. Because if the assembly cycle is increased, the sliding parts will lose material due to corrosion. As a result, the repeated friction force is the root cause of the positioning error of sliding parts. Therefore, it is necessary to engage less corrosive material. Also, the lubricant may be used to reduce the corrosion in minimizing the positioning error of the sliding tool components. In addition, it is important to calculate the number of assembly cycles for efficient fuselage panel assembly.
Originality/value
According to the structure and assembly process characteristics of the fuselage panel, the fuselage panel preassembly tooling can optimize the assembly process of the fuselage panel and have certain practical application values.
Details
Keywords
Doaa Samir Mahmoud, Medhat Lotfy Tawfic, Abdel Gawad Rabie and Salwa H. El-Sabbagh
The purpose of this paper is to prepare superabsorbent polymers (SAPs) based on acrylic acid, which is considered hygroscopic material to incorporate in rubber formulation, which…
Abstract
Purpose
The purpose of this paper is to prepare superabsorbent polymers (SAPs) based on acrylic acid, which is considered hygroscopic material to incorporate in rubber formulation, which results in producing moisten rubber that is used as roofing sheets.
Design/methodology/approach
SAPs were synthesized via free radical bulk polymerization technique using different content of cross-linker N, N'-methylenebisacrylamide and potassium persulfate. Differential scanning calorimeter, thermal gravimetric analysis, Fourier transform infrared spectroscopy and transmission electron microscopy were used to characterize SAPs and confirmed the formation of cross-linked hydrogel structure. The water absorbency and the gel fraction for sodium polyacrylate (NaPA) were investigated. Then, the influence of obtained NaPA on the swelling behavior of the prepared natural rubber (NR) compound has been discussed.
Findings
Absorption characteristics and gel fraction of NaPA were found to depend on the content of the cross-linker in the system. SAPs are used to improve the absorbance behavior and performance of the NR to produce, roofing sheets using in hot weather. The morphology of the obtained rubber compound was well-explained by using a scanning electron microscope.
Research limitations/implications
The research provides a simple way to produce moisten rubber that can be used as a roofing sheet to overcome warm weather.
Originality/value
Moisten rubber roofing sheets provide a low-cost option in many developing countries with hot climates, and thus, help save the environment from global warming.
Details
Keywords
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.
Details
Keywords
Patrick Lindsay Croucamp and Arnesh Telukdarie
Traction substations are an integral part of the railway infrastructure. In order to ensure that machinery and equipment is available and utilised at full capacity, intelligent…
Abstract
Purpose
Traction substations are an integral part of the railway infrastructure. In order to ensure that machinery and equipment is available and utilised at full capacity, intelligent maintenance methods should be implemented. The purpose of this paper is to focus on the development of lean maintenance strategies implemented on traction substations and offer the maintenance manager an alternative maintenance method to be utilised during optimisation initiatives.
Design/methodology/approach
The rail company under consideration has various improvement options, the maintenance supply chain is a priority. The existing maintenance process of 3 kVDC traction substations is examined and all operations and activities directly and indirectly associated with maintenance are analysed with lean methodologies. The analysis of maintenance operations and activities reveals that some of these operations and activities are non-value-adding and, therefore, regarded as waste. These activities only prolong the maintenance process without adding value to the process. Alternative operations and activities are suggested and simulated.
Findings
The application of lean indicates that the maintenance process could be optimised to deliver on a more efficient process, which would improve the quality of maintenance by ensuring that maintenance is timeously carried out. Through reducing the downtime caused by maintenance, the availability of the system is preserved and the railway lines could be used to capacity.
Research limitations/implications
The research is limited to 3 kVDC traction substations and the associated maintenance process, as this was the area of opportunity for the company. The track and overhead traction equipment maintenance is not included.
Practical implications
The practical application of this research is in optimisation of the value chain for maintenance, specifically in the rail industry.
Originality/value
This research could be applied by maintenance managers to effectively implement if a run-to-failure (RTF) maintenance philosophy is being utilised. The research offers maintenance techniques within the RTF maintenance scope which reduces the maintenance cycle and equipment downtime.