Search results
1 – 10 of over 1000Xinyang Liu, Anyu Liu, Xiaoying Jiao and Zhen Liu
The purpose of the study is to investigate the impact of implementing anti-dumping duties on imported Australian wine to China in the short- and long-run, respectively.
Abstract
Purpose
The purpose of the study is to investigate the impact of implementing anti-dumping duties on imported Australian wine to China in the short- and long-run, respectively.
Design/methodology/approach
First, the Difference-in-Differences (DID) method is used in this study to evaluate the short-run causal effect of implementing anti-dumping duties on imported Australian wine to China. Second, a Bayesian ensemble method is used to predict 2023–2025 wine exports from Australia to China. The disparity between the forecasts and counterfactual prediction which assumes no anti-dumping duties represents the accumulated impact of the anti-dumping duties in the long run.
Findings
The anti-dumping duties resulted in a significant decline in red and rose, white and sparkling wine exports to China by 92.59%, 99.06% and 90.06%, respectively, in 2021. In the long run, wine exports to China are projected to continue this downward trend, with an average annual growth rate of −21.92%, −38.90% and −9.54% for the three types of wine, respectively. In contrast, the counterfactual prediction indicates an increase of 3.20%, 20.37% and 4.55% for the respective categories. Consequently, the policy intervention is expected to result in a decrease of 96.11%, 93.15% and 84.11% in red and rose, white and sparkling wine exports to China from 2021 to 2025.
Originality/value
The originality of this study lies in the creation of an economic paradigm for assessing policy impacts within the realm of wine economics. Methodologically, it also represents the pioneering application of the DID and Bayesian ensemble forecasting methods within the field of wine economics.
Details
Keywords
Dangshu Wang, Menghu Chang, Licong Zhao, Yuxuan Yang and Zhimin Guan
This study aims to regarding the application of traditional pulse frequency modulation control full-bridge LLC resonant converters in wide output voltage fields such as on-board…
Abstract
Purpose
This study aims to regarding the application of traditional pulse frequency modulation control full-bridge LLC resonant converters in wide output voltage fields such as on-board chargers, there are issues with wide frequency adjustment ranges and low conversion efficiency.
Design/methodology/approach
To address these issues, this paper proposes a fixed-frequency pulse width modulation (PWM) control strategy for a full-bridge LLC resonant converter, which adjusts the gain by adjusting the duty cycle of the switches. In the full-bridge LLC converter, the two switches of the lower bridge arm are controlled by a fixed-frequency and fixed duty cycle, with their switching frequency equal to the resonant frequency, whereas the two switches of the upper bridge arm are controlled by a fixed-frequency PWM to adjust the output voltage. The operation modes of the converter are analyzed in detail, and a mathematical model of the converter is established. The gain characteristics of the converter under the fixed-frequency PWM control strategy are deeply analyzed, and the conditions for implementing zero-voltage switching (ZVS) soft switching in the converter are also analyzed in detail. The use of fixed-frequency PWM control simplifies the design of resonant parameters, and the fixed-frequency control is conducive to the design of magnetic components.
Findings
According to the fixed-frequency PWM control strategy proposed in this paper, the correctness of the control strategy is verified through simulation and the development and testing of a 500-W experimental prototype. Test results show that the primary side switches of the converter achieve ZVS and the secondary side rectifier diodes achieve zero-current switching, effectively reducing the switching losses of the converter. In addition, the control strategy reduces the reactive circulating current of the converter, and the peak efficiency of the experimental prototype can reach 95.2%.
Originality/value
The feasibility of the fixed-frequency PWM control strategy was verified through experiments, which has significant implications for improving the efficiency of the converter and simplifying the design of resonant parameters and magnetic components in wide output voltage fields such as on-board chargers.
Details
Keywords
Chih-Chin Liang and Annie Pei-I Yu
Impulse purchases are a phenomenon of interest in recent years that provides a high revenue stream for companies compared to planned purchases. Airports are a unique shopping…
Abstract
Purpose
Impulse purchases are a phenomenon of interest in recent years that provides a high revenue stream for companies compared to planned purchases. Airports are a unique shopping environment. Travellers usually need to arrive at the airport early and can only utilise limited time to shop at duty-free stores, which makes the shopping experience time-constrained and has the potential to make impulse purchases. The main purpose of this research is to create a model to examine whether “time pressure” and “hedonic shopping motivation” lead to impulse shopping through the formation of “positive emotion” in the context of airport duty-free shops.
Design/methodology/approach
A questionnaire-based survey was conducted in this study. The data collection for this study targeted individuals who had previously used airline services for international travel and visited duty-free shops at international airports. A total of 502 valid subjects participated in this survey.
Findings
The findings indicated that time pressure and consumers’ hedonic motivations have a positive impact on emotions. Positive emotions have a positive impact on the occurrence of impulse purchases. Music and light can moderate the impact of hedonic motivation on emotion but cannot reduce the influence of time pressure on emotion. Social factor significantly moderates the positive association between hedonic shopping motivation and emotion.
Originality/value
The research collected data from various international airports and social media, enabling the findings to be generalised.
Details
Keywords
Praveen Kumar Bonthagorla and Suresh Mikkili
To generate electricity, solar photovoltaic (PV) systems are among the best, most eco-friendly and most cost-effective solutions available. Extraction of maximum possible…
Abstract
Purpose
To generate electricity, solar photovoltaic (PV) systems are among the best, most eco-friendly and most cost-effective solutions available. Extraction of maximum possible electricity from the solar PV system is complicated by a number of factors brought on by the ever-changing weather conditions under which it must operate. Many conventional and evolutionary algorithm-based maximum power point tracking (MPPT) techniques have the limitation of not being able to extract maximum power under partial shade and rapidly varying irradiance. Hence, the purpose of this paper is to propose a novel hybrid slime mould assisted with perturb and observe (P&O) global MPPT technique (HSMO) for the hybrid bridge link-honey comb (BL-HC) configured PV system to enhance the better maximum power during dynamic and steady state operations within less time.
Design/methodology/approach
In this method, a hybridization of two algorithms is proposed to track the true with faster convergence under PSCs. Initially, the slime mould optimization (SMO) algorithm is initiated for exploration of optimum duty cycles and later P&O algorithm is initiated for exploitation of global duty cycle for the DC–DC converter to operate at GMPP and for fast convergence.
Findings
The effectiveness of the proposed HSMO MPPT is compared with adaptive coefficient particle swarm optimization (ACPSO), flower pollination algorithm and SMO MPPT techniques in terms of tracked GMPP, convergence time/tracking speed and efficacy under six complex partial shading conditions. From the results, it is noticed that the proposed algorithm tracks the true GMPP under most of the shading conditions with less tracking time when compared to other MPPT techniques.
Originality/value
This paper proposes a novel hybrid slime mould assisted with perturb and observe (P&O) global MPPT technique (HSMO) for the hybrid BL-HC configured PV system enhance the better maximum power under partial shading conditions (PSCs). This method operated in two stages as SMO for exploration and P&O for exploitation for faster convergence and to track true GMPP under PSCs. The proposed approach largely improves the performance of the MPP tracking of the PV systems. Initially, the proposed MPPT technique is simulated in MATLAB/Simulink environment. Furthermore, an experimental setup has been designed and implemented. Simulation results obtained are validated through experimental results which prove the viability of the proposed technique for an efficient green energy solution.
Details
Keywords
Prosun Mandal, Srinjoy Chatterjee and Shankar Chakraborty
In many of today’s manufacturing industries, such as automobile, aerospace, defence, die and mould making, medical and electrical discharge machining (EDM) has emerged as an…
Abstract
Purpose
In many of today’s manufacturing industries, such as automobile, aerospace, defence, die and mould making, medical and electrical discharge machining (EDM) has emerged as an effective material removal process. In this process, a series of discontinuous electric discharges is used for removing material from the workpiece in the form of craters generating a replica of the tool into the workpiece in a dielectric environment. Appropriate selection of the tool electrode material and combination of input parameters is an important requirement for performance enhancement of an EDM process. This paper aims to optimize an EDM process using single-valued neutrosophic grey relational analysis using Cu-multi-walled carbon nanotube (Cu-MWCNT) composite tool electrode.
Design/methodology/approach
This paper proposes the application of grey relational analysis (GRA) in a single-valued neutrosophic fuzzy environment to identify the optimal parametric intermix of an EDM process while considering Cu-MWCNT composite as the tool electrode material. Based on Taguchi’s L9 orthogonal array, nine experiments are conducted at varying combinations of four EDM parameters, i.e. pulse-on time, duty factor, discharge current and gap voltage, with subsequent measurement of two responses, i.e. material removal rate (MRR) and tool wear rate (TWR). The electrodeposition process is used to fabricate the Cu-MWCNT composite tool.
Findings
It is noticed that both the responses would be simultaneously optimized at higher levels of pulse-on time (38 µs) and duty factor (8), moderate level of discharge current (5 A) and lower level of gap voltage (30 V). During bi-objective optimization (maximization of MRR and minimization of TWR) of the said EDM process, the achieved values of MRR and TWR are 243.74 mm3/min and 0.001034 g/min, respectively.
Originality/value
Keeping in mind the type of response under consideration, their measured values for each of the EDM experiments are expressed in terms of linguistic variables which are subsequently converted into single-valued neutrosophic numbers. Integration of GRA with single-valued neutrosophic sets would help in optimizing the said EDM process with the Cu-MWCNT composite tool while simultaneously considering truth-membership, indeterminacy membership and falsity-membership degrees in a human-centric uncertain decision-making environment.
Details
Keywords
Mohamed Mousa, Ahmad Arslan, Hala Abdelgaffar, Jean Pierre Seclen Luna and Bernardo Ramon Dante De la Gala Velasquez
This paper aim to analyse the motives behind the commitment of nurses to their profession despite their intense job duties during the COVID-19 pandemic.
Abstract
Purpose
This paper aim to analyse the motives behind the commitment of nurses to their profession despite their intense job duties during the COVID-19 pandemic.
Design/methodology/approach
The empirical sample comprises of 35 semi-structured interviews with public sector hospital nurses in under-researched contexts of Egypt and Peru.
Findings
Three types of motives were found to play a critical role in nurses’ commitment to their profession despite the difficulties associated with extreme work conditions. These factors include cultural (religious values, governmental coercion), contextual (limited education, organisational support) and personal (good nurse identity, submissive nature) dimensions.
Originality/value
This paper is one of the pioneering works to link existing literature streams on career commitment, extreme jobs, extreme context and management under disruptions (particularly COVID-19) by analysing these aspects in the under-researched Peruvian and Egyptian contexts.
Details
Keywords
Ali Hashemi, Hamed Taheri and Mohammad Dehghani
To prevent the coil from burning or getting damaged, it is necessary to estimate the duration of its operation as long as its temperature does not exceed the permissible limit…
Abstract
Purpose
To prevent the coil from burning or getting damaged, it is necessary to estimate the duration of its operation as long as its temperature does not exceed the permissible limit. This paper aims to investigate the effect of switching on the thermal behavior of impregnated and nonimpregnated windings. Also, the safe operating time for each winding is determined.
Design/methodology/approach
The power loss of the winding is expressed as a function of the winding specifications. Using homogenization techniques, the equivalent thermal properties for the homogenized winding are calculated and used in a proposed thermal equivalent circuit for winding modeling and analysis. The validity and accuracy of the proposed model are determined by comparing its analysis results and simulation and measurement results.
Findings
The results show that copper windings have better thermal behavior and lower temperature compared to aluminum windings. On the other hand, by impregnating or increasing the packing factor of the winding, the thermal behavior is improved. Also, by choosing the right duty cycle for the winding current source, it is possible to prevent the burning or damage of the winding and increase its lifespan. Comparing the measurement results with the analysis results shows that the proposed equivalent circuit has an error of less than 4% in the calculation of the winding center temperature.
Research limitations/implications
In this paper, the effect of temperature on the electrical resistance of the coil is ignored. Also, rectangular wires were not investigated. Research in these topics are considered as future work.
Originality/value
By calculating the thermal time constant of the winding, its safe operation time can be calculated so that its temperature does not exceed the tolerable value (150 °C). The proposed method analyzes both impregnated and nonimpregnated windings with various schemes. It investigates the effects of switching on their thermal behavior. Additionally, it determines the safe operating time for each type of winding.
Details
Keywords
Edirimuni Nadeesh Rangana de Silva
South Asia is a region urgently seeking development, although it has failed in regional integration. It is the second least integrated region regarding the number of Free Trade…
Abstract
Purpose
South Asia is a region urgently seeking development, although it has failed in regional integration. It is the second least integrated region regarding the number of Free Trade Agreements (FTAs) and can thus be recognised as a missing bloc in the global multilateral system. This study aims to focus on South Asian FTAs and explores the problems of the inter-relations and compatibility between the systemic and regional trade systems.
Design/methodology/approach
The study proposes a framework to benchmark the compatibility of South Asian FTAs with WTO rules. Primary data from 2000 to 2020, including descriptive analyses of reports, legal text of the FTAs, official documents and factual presentations, have been collected and analysed through thematic analysis using the proposed framework.
Findings
The study finds that, although South Asian FTAs meet most of the WTO requirements, they are not progressing toward facilitating and promoting trade. Data from 2000 to 2020 show us that South Asian FTAs have not significantly impacted trade between themselves. The study argues that, although South Asian FTAs fulfil some benchmarks, they show only a lukewarm interest in contributing to the international trading system as building blocs. It is therefore recommended that the case of South Asian trade liberalisation must be understood contextually and be given careful and exclusive attention by the WTO.
Originality/value
As such, this study is the first to claim that South Asian FTAs are not fully compatible with the WTO rules. They remain a missing regional bloc in the multilateral system, rather than a building bloc or a stumbling bloc, delaying the region’s opportunity to develop as a region and within the larger system.
Details
Keywords
Biranchi Narayan Kar, Paulson Samuel, Jatin Kumar Pradhan and Amit Mallick
This paper aims to present an improvement to the power quality of the grid by using a colliding body optimization (CBO) based proportional-integral (PI) compensated design for a…
Abstract
Purpose
This paper aims to present an improvement to the power quality of the grid by using a colliding body optimization (CBO) based proportional-integral (PI) compensated design for a grid-connected solar photovoltaic-fed brushless DC motor (BLDC)-driven water pumping system with a bidirectional power flow control. The system with bidirectional power flow allows driving the pump at full proportions uninterruptedly irrespective of the weather conditions and feeding a grid when water pumping is not required.
Design/methodology/approach
Here, power quality issue is taken care of by the optimal generation of the duty cycle of the voltage source converter. The duty cycle is optimally generated by optimal selection of the gains of the current controller (i.e. PI), with the CBO technique resulting in a nearly unity power factor as well as lower total harmonic distortion (THD) of input current. In the CBO technique, the gains of the PI controller are considered as agents and collide with each other to obtain the best value. The system is simulated using MATLAB/Simulink and validated in real time with OPAL RT simulator, OP5700.
Findings
It was found that the power quality of grid using the CBO technique has improved much better than the particle swarm optimization and Zeigler–Nichols approach. The bidirectional flow of control of VSC allowed for optimum resource utilization and full capacity of water pumping whatever may be weather conditions.
Originality/value
Improved power quality of grid by optimally generation of the duty cycle for the proposed system. A unit vector tamplate generation technique is used for bidirectional power transfer.
Details
Keywords
This paper aims to reveal how different types of events and top management teams' (TMTs’) cognitive frames affect the generation of breakthrough innovations.
Abstract
Purpose
This paper aims to reveal how different types of events and top management teams' (TMTs’) cognitive frames affect the generation of breakthrough innovations.
Design/methodology/approach
Drawing on the event system theory and upper echelon theory, this study chose a Chinese manufacturing enterprise as the case firm and conducted an exploratory single-case study to unpack how breakthrough innovation generates over time.
Findings
By conducting the in-depth case analysis, the study revealed that firms do not produce breakthrough innovation in the catch-up stage and parallel-running stage but achieve it in the leading stage. It also indicated that when facing proactive events in the catch-up stage, TMTs often adopt a contracted lens, being manifested as consistency orientation, less elastic organizational identity and narrower competitive boundaries. In addition, they tend to adopt a contracted lens when facing reactive and proactive events in the parallel-running stage. In the face of reactive and proactive events in the leading stage, they are more inclined to adopt an expanded lens, being manifested as a coexistence orientation, more elastic organizational identity and wider competitive boundaries.
Originality/value
First, by untangling how TMT's cognitive frame functions in breakthrough innovations, this paper provides a micro-foundation for producing breakthrough innovations and deepens the understanding of upper echelon theory by considering the cognitive dimension of TMTs. Second, by teasing out several typical events experienced by the firm, this paper is the first attempt to reveal how events affect the generation of breakthrough innovation. Third, the work extends the application of the event system theory in technological innovation. It also provides insightful implications for promoting breakthrough innovations by considering the role of proactive and reactive events a firm experiences and TMT's perceptions.
Details