Rui Liu, Jing Sheng, Jie Ma, Guang Yang, Xuefei Dong and Yongsheng Liang
The purpose of this paper is to investigate the knock combustion characteristics, including the combustion pressure, heat release rate (HRR) and knock intensity of aviation…
Abstract
Purpose
The purpose of this paper is to investigate the knock combustion characteristics, including the combustion pressure, heat release rate (HRR) and knock intensity of aviation kerosene fuel, that is, Rocket Propellant 3 (RP-3), on a port-injected two-stoke spark ignition (SI) engine.
Design/methodology/approach
Experimental investigation using a bench test and the statistical analysis of data to reflect the knock combustion characteristics of the two-stroke SI unmanned aerial vehicle (UAV) engine on RP-3 kerosene fuel.
Findings
Under the full load condition of 4,000 rpm, at the ignition timing of 25 degree of crank angle (°CA) before top dead centre (BTDC), the knock combustion is sensitive to the thinner mixture; therefore, the knock begins to occur when the excess air ratio is larger than 1.0. When the excess air ratio is set as 1.2, the knock obviously appears with the highest knock intensity. At the excess air ratio of 1.2, better engine performance is obtained at the ignition timing range of 20-30 °CA BTDC. However, the ignition timing at 30° CA BTDC significantly increases the peak combustion pressure and knock intensity with the advancing heat release process.
Practical implications
Gasoline has a low flash point, a high-saturated vapour pressure and relatively high volatility, and it is a potential hazard near a naked flame at room temperature, which can create significant security risks for its storage, transport and use. The authors adopt a low-volatility single RP-3 kerosene fuel for all vehicles and equipment to minimise the number of different devices using various fuels and improve the military application safety.
Originality/value
Most two-stroke SI UAV engines for military applications burn gasoline. A kerosene-based fuel for stable engine operation can be achieved because the knock combustion can be effectively suppressed through the combined adjustment of the fuel amount and spark timing.
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Hao Chen, Xiaoming Zheng and Lijuan Liu
Ethical decision making, business ethics.
Abstract
Subject area
Ethical decision making, business ethics.
Study level/applicability
This case is applicable to MBA, EDP and EMBA courses.
Case overview
TOREAD, a professional provider of outdoor equipment in China, started in business by producing and selling tents. To meet market demand, TOREAD expanded its product line which ranges from outdoor durable tent products to “pan-outdoor” products including footwear and clothing. During the critical expansion phase, TOREAD was challenged by a quality problem in a batch of outsourced sandals that had been manufactured by a contracted supplier. By researching different options and going through an ethical decision making process, TOREAD made the choice of destroying all “problem sandals”. Since then, TOREAD has focused development on product quality improvement and product innovation to establish a sustainable brand image and generate social benefits. TOREAD's decision making in the critical development phase helped it to become the leader in the outdoor product industry in China.
Expected learning outcomes
This case may be used for courses such as business ethics and strategy. By learning this case, students can understand the process of making ethical decisions when facing moral dilemmas among corporate decision makers, employees and relevant interested parties, and learn how to make strategic decisions to balance company profit growth and social benefits in critical development phases.
Supplementary materials
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Jing Sheng, Zhen He and Xing Shi
Quality Functioni Deployment (QFD) is a useful planning process in new product development. It achieves the maximum custom satisfaction through translating Voice of the Customer…
Abstract
Quality Functioni Deployment (QFD) is a useful planning process in new product development. It achieves the maximum custom satisfaction through translating Voice of the Customer (VOC) into voice of the engineer in the House of Quality (HOQ), and ensures the customer focus from house to house translation. In QFD, the relationship matrix and correlation matrix are important pars, which will influence the final priorities of the technical response. According to the traditional methods, these matrices are determined by the people’s experience and filled with ordinal numbers. It would inevitably result in inaccuracy and curtness. Design of Experiments (DOE) is employed to determine the effect of variables on the process. In this paper, the author puts forward the idea of integrating DOE into the process of QFD. This integration helps to produce scientific decision and robust product design. A famework on QFD/DOE is presented and explanations are also made.
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Chung Ket Thein and Jing‐Sheng Liu
The aim of this paper is to present a novel multifactor structural optimisation method incorporating reliability performance.
Abstract
Purpose
The aim of this paper is to present a novel multifactor structural optimisation method incorporating reliability performance.
Design/methodology/approach
This research addresses structural optimisation problems in which the design is required to satisfy multiple performance criteria, such as strength, stiffness, mass and reliability under multiple loading cases simultaneously. A MOST technique is extended to accommodate the reliability‐related optimisation. Structural responses and geometrical sensitivities are analysed by a FE method, and reliability performance is calculated by a reliability loading‐case index (RLI). The evaluation indices of performances and loading cases are formulated, and an overall performance index is presented to quantitatively evaluate a design.
Findings
The proposed method is applicable to multi‐objective, multi‐loading‐case, multi‐disciplinary and reliability‐related optimisation problems. The applications to a star‐like truss structure and a raised‐access floor panel structure confirmed that the method is highly effective and efficient in terms of structural optimisation.
Originality/value
A systematic method is proposed. The optimisation method combines the MOST technique with a RLI (a new alternative route to calculate the reliability index at multiple loading cases) using a parametric FE model.
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Chi-I Lin and Yuh-Yuh Li
This study aims to investigate the potential of an empathetic mindset aimed at empowering undergraduate students to work toward sustainable development (SD), addressing both…
Abstract
Purpose
This study aims to investigate the potential of an empathetic mindset aimed at empowering undergraduate students to work toward sustainable development (SD), addressing both theoretical and practical dimensions.
Design/methodology/approach
A mixed quantitative and qualitative research method was used in this study. Cross-sectional quantitative survey data on students’ mindsets and actions toward SD was collected to examine the theoretical relationship between belief and behavior. Qualitative inquiry using focus-group interviews explored students’ on-site learning experiences.
Findings
This study provides evidence for the impact of an empathetic mindset on education for sustainable development (ESD). Results showed that students with a more empathetic mindset showed better attitudes and behaviors toward SD actions. Findings suggest that developing an empathetic mindset improves students’ attitudes toward taking substantial action to protect the environment.
Originality/value
This study introduces a novel perspective extending the application of empathetic mindset in ESD.
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Zhang Jing and Kong Dejun
To improve the electrochemical corrosion resistance of cold sprayed Al coating.
Abstract
Purpose
To improve the electrochemical corrosion resistance of cold sprayed Al coating.
Design/methodology/approach
A cold sprayed aluminum (Al) coating fabricated on S355 structural steel was oxidized using a micro arc oxidation (MAO). The electrochemical corrosion and impedance spectroscopy were tested to investigate its corrosion performance.
Findings
The MAO film is primarily α-Al2O3 and γ-Al2O3, which increases its density and surface quality. The corrosion potential is positively shifted by 0.2 V, and the electrochemical impedance is significantly increased.
Originality/value
A cold sprayed Al coating on S355 steel was first oxidized using a MAO. The effects of MAO on the microstructure of Al coating were investigated to analyze its electrochemical corrosion behavior.
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Min Li, Hangxuan Liu, Xingquan Zhang, Hengji Yang, Lisheng Zuo, Ziyu Wang, Shiwei Duan and Song Shu
The purpose of this paper is to investigate the effect of laser peening (LP) on mechanical and wear properties of 304 stainless steel sheet.
Abstract
Purpose
The purpose of this paper is to investigate the effect of laser peening (LP) on mechanical and wear properties of 304 stainless steel sheet.
Design/methodology/approach
Three-dimensional morphology, micro-hardness and micro-structure of shocked samples were tested. The wear amount, wear track morphology and wear mechanism were also characterized under dry sliding wear using Al2O3 ceramics ball.
Findings
The LP treatment generates deformation twins that contribute to the grain refinement and hardness increase. The wear test displays that the wear mechanism of samples is mainly abrasive wear and oxidation wear at 10 N load. While at 30 N, the delamination and adhesion areas of treated sample are reduced visibly compared to untreated ones.
Originality/value
This study specifically investigates the mechanical and wear properties of 304 stainless steel after the direct action of LP on its surface, which shows an effective improvement on the wear resistance. For example, the wear loss of processed sample is reduced by 19% at 30 N, the friction coefficient decreases from 0.4714 to 0.4308 and the groove depth is reduced from 78.1 to 74.4 µm under same condition.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2024-0007/
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Chengchao Bai, Jifeng Guo, Wenyuan Zhang, Tianhang Liu and Linli Guo
The purpose of this paper is to verify the feasibility of lunar capture braking through three methods based on particle swarm optimization (PSO) and compare the advantages and…
Abstract
Purpose
The purpose of this paper is to verify the feasibility of lunar capture braking through three methods based on particle swarm optimization (PSO) and compare the advantages and disadvantages of the three strategies by analyzing the results of the simulation.
Design/methodology/approach
The paper proposes three methods to verify capture braking based on PSO. The constraints of the method are the final lunar orbit eccentricity and the height of the final orbit around the Moon. At the same time, fuel consumption is used as a performance indicator. Then, the PSO algorithm is used to optimize the track of the capture process and simulate the entire capture braking process.
Findings
The three proposed braking strategies under the framework of PSO algorithm are very effective for solving the problem of lunar capture braking. The simulation results show that the orbit in the opposite direction of the trajectory has the most serious attenuation at perilune, and it should consume the least amount of fuel in theoretical analysis. The methods based on the fixed thrust direction braking and thrust uniform rotation braking can better ensure the final perilune control accuracy and fuel consumption. As for practice, the fixed thrust direction braking method is better realized among the three strategies.
Research limitations/implications
The process of lunar capture is a complicated process, involving effective coordination between multiple subsystems. In this article, the main focus is on the correctness of the algorithm, and a simplified dynamic model is adopted. At the same time, because the capture time is short, the lunar curvature can be omitted. Furthermore, to better compare the pros and cons of different braking modes, some influence factors and perturbative forces are not considered, such as the Earth’s flatness, light pressure and system noise and errors.
Practical implications
This paper presents three braking strategies that can satisfy all the constraints well and optimize the fuel consumption to make the lunar capture more effective. The results of comparative analysis demonstrate that the three strategies have their own superiority, and the fixed thrust direction braking is beneficial to engineering realization and has certain engineering practicability, which can also provide reference for lunar exploration orbit design.
Originality/value
The proposed capture braking strategies based on PSO enable effective capture of the lunar module. During the lunar exploration, the capture braking phase determines whether the mission will be successful or not, and it is essential to control fuel consumption on the premise of accuracy. The three methods in this paper can be used to provide a study reference for the optimization of lunar capture braking.
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Hongyan Zhu, Xiaochong Wu, Pengzhen Lv, Yuansheng Wang, Huagang Lin, Wei Liu and Zhufeng Yue
Improvement and optimization design of a two-stage vibration isolation system proposed in this paper are conducted to ensure the device of electronic work effective.
Abstract
Purpose
Improvement and optimization design of a two-stage vibration isolation system proposed in this paper are conducted to ensure the device of electronic work effective.
Design/methodology/approach
The proposed two-stage vibration isolation system of airborne equipment is optimized and parameterized based on multi-objective genetic algorithm.
Findings
The results show that compared with initial two-stage vibration isolation system, the angular vibration of the two-stage vibration isolation system becomes 3.55 × 10-4 rad, which decreases by 89%. The linear isolation effect is improved by at least 67.7%.
Originality/value
The optimized two-stage vibration isolation system effectively improves the vibration reduction effect, the resonance peak is obviously improved and the reliability of the mounting bracket and the shock absorber is highly improved, which provides an analysis method for two-stage airborne equipment isolation design under complex dynamic environment.
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Rashmi Singh and Jogendra Kumar Nayak
The purpose of this study is to examine the effect of work-family conflicts (WFC) on job stress and its subsequent impact on job satisfaction among the police officials. It also…
Abstract
Purpose
The purpose of this study is to examine the effect of work-family conflicts (WFC) on job stress and its subsequent impact on job satisfaction among the police officials. It also examined the moderating effect of the social support from organisations between employees’ job stress and satisfaction.
Design/methodology/approach
The authors conducted a survey on 599 police officials associated with 20 police stations in New Delhi, India. The study involved a hierarchical regression analysis to examine the relationship between independent (WFC) and dependent (satisfaction) variable with the mediator (stress) as well as the moderator (social support).
Findings
The findings revealed that stress mediated the relationship between WFC and satisfaction of the police officials. Further, social support acted as a moderator between their job stress and satisfaction.
Practical implications
The study findings added a new chapter in the existing literature by developing a comprehensive framework that considers different dimensions, i.e. WFC and job stress in Indian context.
Originality/value
The study has originality and offers value to police organisation as it focuses on police officials, and explores their WFC and job stress and its subsequent effect on their job satisfaction.