The purpose of this study is to present a newly proposed and developed sorting algorithm-based merging weighted fraction Monte Carlo (SAMWFMC) method for solving the population…
Abstract
Purpose
The purpose of this study is to present a newly proposed and developed sorting algorithm-based merging weighted fraction Monte Carlo (SAMWFMC) method for solving the population balance equation for the weighted fraction coagulation process in aerosol dynamics with high computational accuracy and efficiency.
Design/methodology/approach
In the new SAMWFMC method, the jump Markov process is constructed as the weighted fraction Monte Carlo (WFMC) method (Jiang and Chan, 2021) with a fraction function. Both adjustable and constant fraction functions are used to validate the computational accuracy and efficiency. A new merging scheme is also proposed to ensure a constant-number and constant-volume scheme.
Findings
The new SAMWFMC method is fully validated by comparing with existing analytical solutions for six benchmark test cases. The numerical results obtained from the SAMWFMC method with both adjustable and constant fraction functions show excellent agreement with the analytical solutions and low stochastic errors. Compared with the WFMC method (Jiang and Chan, 2021), the SAMWFMC method can significantly reduce the stochastic error in the total particle number concentration without increasing the stochastic errors in high-order moments of the particle size distribution at only slightly higher computational cost.
Originality/value
The WFMC method (Jiang and Chan, 2021) has a stringent restriction on the fraction functions, making few fraction functions applicable to the WFMC method except for several specifically selected adjustable fraction functions, while the stochastic error in the total particle number concentration is considerably large. The newly developed SAMWFMC method shows significant improvement and advantage in dealing with weighted fraction coagulation process in aerosol dynamics and provides an excellent potential to deal with various fraction functions with higher computational accuracy and efficiency.
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Hongmei Liu and Tat Leung Chan
The purpose of this paper is to study the evolution and growth of aerosol particles in a turbulent planar jet by using the newly developed large eddy simulation…
Abstract
Purpose
The purpose of this paper is to study the evolution and growth of aerosol particles in a turbulent planar jet by using the newly developed large eddy simulation (LES)-differentially weighted operator splitting Monte Carlo (DWOSMC) method.
Design/methodology/approach
The DWOSMC method is coupled with LES for the numerical simulation of aerosol dynamics in turbulent flows.
Findings
Firstly, the newly developed and coupled LES-DWOSMC method is verified by the results obtained from a direct numerical simulation-sectional method (DNS-SM) for coagulation occurring in a turbulent planar jet from available literature. Then, the effects of jet temperature and Reynolds number on the evolution of time-averaged mean particle diameter, normalized particle number concentration and particle size distributions (PSDs) are studied numerically on both coagulation and condensation processes. The jet temperature and Reynolds number are shown to be two important parameters that can be used to control the evolution and pattern of PSD in an aerosol reactor.
Originality/value
The coupling between the Monte Carlo method and turbulent flow still encounters many technical difficulties. In addition, the relationship between turbulence, particle properties and collision kernels of aerosol dynamics is not yet well understood due to the theoretical limitations and experimental difficulties. In the present study, the developed and coupled LES-DWOSMC method is capable of solving the aerosol dynamics in turbulent flows.
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The purpose of this paper is to study the soot formation and evolution by using this newly developed Lagrangian particle tracking with weighted fraction Monte Carlo (LPT-WFMC…
Abstract
Purpose
The purpose of this paper is to study the soot formation and evolution by using this newly developed Lagrangian particle tracking with weighted fraction Monte Carlo (LPT-WFMC) method.
Design/methodology/approach
The weighted soot particles are used in this MC framework and is tracked using Lagrangian approach. A detailed soot model based on the LPT-WFMC method is used to study the soot formation and evolution in ethylene laminar premixed flames.
Findings
The LPT-WFMC method is validated by both experimental and numerical results of the direct simulation Monte Carlo (DSMC) and Multi-Monte Carlo (MMC) methods. Compared with DSMC and MMC methods, the stochastic error analysis shows this new LPT-WFMC method could further extend the particle size distributions (PSDs) and improve the accuracy for predicting soot PSDs at larger particle size regime.
Originality/value
Compared with conventional weighted particle schemes, the weight distributions in LPT-WFMC method are adjustable by adopting different fraction functions. As a result, the number of numerical soot particles in each size interval could be also adjustable. The stochastic error of PSDs in larger particle size regime can also be minimized by increasing the number of numerical soot particles at larger size interval.
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The purpose of this study is to investigate the aerosol dynamics of the particle coagulation process using a newly developed weighted fraction Monte Carlo (WFMC) method.
Abstract
Purpose
The purpose of this study is to investigate the aerosol dynamics of the particle coagulation process using a newly developed weighted fraction Monte Carlo (WFMC) method.
Design/methodology/approach
The weighted numerical particles are adopted in a similar manner to the multi-Monte Carlo (MMC) method, with the addition of a new fraction function (α). Probabilistic removal is also introduced to maintain a constant number scheme.
Findings
Three typical cases with constant kernel, free-molecular coagulation kernel and different initial distributions for particle coagulation are simulated and validated. The results show an excellent agreement between the Monte Carlo (MC) method and the corresponding analytical solutions or sectional method results. Further numerical results show that the critical stochastic error in the newly proposed WFMC method is significantly reduced when compared with the traditional MMC method for higher-order moments with only a slight increase in computational cost. The particle size distribution is also found to extend for the larger size regime with the WFMC method, which is traditionally insufficient in the classical direct simulation MC and MMC methods. The effects of different fraction functions on the weight function are also investigated.
Originality Value
Stochastic error is inevitable in MC simulations of aerosol dynamics. To minimize this critical stochastic error, many algorithms, such as MMC method, have been proposed. However, the weight of the numerical particles is not adjustable. This newly developed algorithm with an adjustable weight of the numerical particles can provide improved stochastic error reduction.
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Victor Wong and Tat Chor Au-Yeung
The purpose of this paper is to critically examine the youth narratives of Mr Leung Chun-ying, the Chief Executive (CE) of the Hong Kong Special Administrative Region (HKSAR…
Abstract
Purpose
The purpose of this paper is to critically examine the youth narratives of Mr Leung Chun-ying, the Chief Executive (CE) of the Hong Kong Special Administrative Region (HKSAR) Government between 2012 and 2017, which steered the directions of youth policies in Hong Kong.
Design/methodology/approach
Informed by the ideational school of institutionalism, a qualitative documentary study was conducted to analyse the policy addresses, speeches, and blog posts delivered by the then CE, which were all available on the website of the HKSAR Government. It was through a thematic analysis of the database that themes and sub-themes were generated for the discussion. Representative verbatim quotes are used for illustrating some of the youth policy ideas and discourses promoted under the Leung’s regime.
Findings
The findings suggest that the governing youth narratives could be categorised into two interrelated themes: behavioural patriotism and economic opportunism. The notions of youth development constructed in the narratives of Leung shape the definition of youth-related problems and solutions in relation to national identity and global competition.
Research limitations/implications
This study focusses on the previous term of HKSAR Government that cannot fully reveal the extent of policy continuities and changes. Yet, it could outline the overall picture and address the shortcomings of Hong Kong’s current youth policies viewed from both normative and cognitive perspectives. Methodological and analytical implications can be drawn for further studies on policy ideas and discourses.
Originality/value
The paper has two major contributions; the first of which is the illustration of an analytical framework connecting contents, tools, and justification of policies for capturing the dynamics and complexities of youth policies. Second, the findings of this study develop a critical understanding of neoliberal youth policies in both economic and moral senses that pose new challenges to young people and policy makers.
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Ka Ki Chan and Tat Chor Au-Yeung
Retirement protection has been widely debated in Hong Kong over two decades. The debate about the relationship between social insecurity and retirement protection, and provoked…
Abstract
Purpose
Retirement protection has been widely debated in Hong Kong over two decades. The debate about the relationship between social insecurity and retirement protection, and provoked consideration of a choice between a rights-based universal retirement system and means-tested protection for senior citizens are still contested. This study aims to explore the understanding and behaviours of young workers regarding retirement planning, their difficulties and worries with the implementation of providing support for their parents' retirement.
Design/methodology/approach
This was an exploratory study to target young workers aged 20–34 years to participate. Qualitative data presented in this study were drawn from 16 young workers. Seven were female and nine were male young workers.
Findings
The research found that young workers who have a relatively low level of income, particularly for non-standard workers and the self-employed, both are likely to find difficulties to contribute to their own retirement planning and their parents' retirement with the emerging problems of job insecurity and instability. Young working people in lower socio-classes have further limited choices and control over their own retirement planning, as well as providing support for their parents' retirement that may cause a breach of intergenerational contract.
Originality/value
With the increasing number of young workers with precarious employment or unemployment, this study has contributed to a shift in views regarding intergenerational contracts, particularly in the need to support other generations of family members in a contemporary Hong Kong society.
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Tat Y. Lee, Hareton K.N. Leung and Keith C.C. Chan
A comprehensive survey was conducted with a view to identifying the benefits derived by ISO 9000 certified companies in Hong Kong. It is generally agreed that the certification…
Abstract
A comprehensive survey was conducted with a view to identifying the benefits derived by ISO 9000 certified companies in Hong Kong. It is generally agreed that the certification helps the companies to improve quality in terms of work procedures, product and service quality, team spirit, subcontractor control, efficiency and complaints. While a large proportion of the certified companies would like to continuously improve their quality on the basis of the certified management system, many of them do not know how to make a start. This paper reviews the difference between what is commonly known as good practice and the ISO 9000 requirements. Some recommendations are made for the certified companies which are planning to develop their quality journey based on ISO 9000.
The purpose of this paper is to assess the intra-party conflicts in Hong Kong’s Democratic Party (DP) and their implications for broader democratic processes in the territory. It…
Abstract
Purpose
The purpose of this paper is to assess the intra-party conflicts in Hong Kong’s Democratic Party (DP) and their implications for broader democratic processes in the territory. It also examines some other thematic issues including: the party’s policy decision-making process, candidate selection, party membership and mergers, and their overall relevance for democratisation in Hong Kong.
Design/methodology/approach
The study gives a historical review of intra-party conflicts. The concept of factionalism is applied to better understand the DP in Hong Kong’s political space.
Findings
Hong Kong is unique and popular models of party conflicts are hardly applicable to the country. Intra-party conflict is an obvious, expected conflict because of differences in formation, leadership, manifestoes and ideologies. The present author tries to examine the case with a view to making a novel contribution.
Originality/value
The study of political factionalism is not uncommon in Hong Kong but this paper intends to study intra-party elite conflicts and self-democratisation of the Hong Kong DP as a case study which is seldom addressed. Consolidation is a possible scenario and its presence is evident when political elites increasingly demonstrate commitment towards creating a democratic regime and when they hold strong beliefs in democratic procedures and institutions as crucial to governing public life.
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The purpose of this paper is to trace the changing pattern of identity politics in Hong Kong Special Administrative Region (HKSAR). It shows that in response to the massive urban…
Abstract
Purpose
The purpose of this paper is to trace the changing pattern of identity politics in Hong Kong Special Administrative Region (HKSAR). It shows that in response to the massive urban renewal projects in the 2000s, “civic localism” in the form of cultural preservation movement emerged to protect local community culture against the government-business hegemony. However, due to the deepening of social integration between Hong Kong and the mainland, a new “anti-mainland localism” emerged in the 2010s against the influx of mainlanders. In 2015–2016, as a result of Beijing’s active interference in Hong Kong affairs, localism is further transformed to Hong Kong “independence.”
Design/methodology/approach
This paper uses a historical methodology to trace the changing pattern of identity politics in Hong Kong after it becomes a special administrative region of China in 1997.
Findings
It shows how the interaction among the following three factors has shaped the pattern of localism in Hong Kong: macro historical-structural context, social movement dynamics and the response of Hong Kong and mainland government.
Practical implications
This paper argues that Beijing’s hardline policy toward Hong Kong localism may work in the short run to all push the pro-independence activities underground. However, unless the structural contradiction of the HKSAR is resolved, it seems likely that anti-mainland localism and Hong Kong independence sentiment and movement will come back with a vengeance at a later stage.
Originality/value
The literature tends to discuss Hong Kong localism in very general terms and fails to reveal its changing nature. This paper contributes by distinguishing three different forms of localism: civic localism in the mid-2000s, anti-mainland in the late 2000s and early 2010s, and independence after 2016. It shows how the macro historical-structural transformation, social movement dynamics and the responses of the Hong Kong SAR government and Beijing government have led to the changes of civic localism to anti-mainland localism, and finally to independence.
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Purpose: This paper contains an evaluation of the results from a survey on ISO 9000 certified hotels in Egypt. This study is focused on factors influencing the choice of the…
Abstract
Purpose: This paper contains an evaluation of the results from a survey on ISO 9000 certified hotels in Egypt. This study is focused on factors influencing the choice of the registration agency; problems with registration agencies; satisfaction level with the registration agencies and the use of training and consultancy in achieving the certification. Design/methodology/approach: Postal survey was used in this study to gather the required data from a sample size of 40 certified large hotels in Egypt. The sample was drawn from a list provided by ISO 9000 certification office in Egypt. A response rate of 60 per cent was achieved. Findings: The certified hotels in Egypt performed well in their registration process and benefited from ISO implementation. They were using their registration agencies for private consultancy and it has been recommended that they should avoid using their registration agencies for private consultancy as this creates conflict of interest and constitutes a violation of ISO 62. Originality/value: Adds to the body of knowledge concerning the ISO 9000 registration agencies in the service sector with particular focus on Egypt.