Mohammad Haji Mohammadi and Joshua R. Brinkerhoff
Turbomachinery, including pumps, are mainly designed to extract/produce energy from/to the flow. A major challenge in the numerical simulation of turbomachinery is the inlet flow…
Abstract
Purpose
Turbomachinery, including pumps, are mainly designed to extract/produce energy from/to the flow. A major challenge in the numerical simulation of turbomachinery is the inlet flow rate, which is routinely treated as a known boundary condition for simulation purposes but is properly a dependent output of the solution. As a consequence, the results from numerical simulations may be erroneous due to the incorrect specification of the discharge flow rate. Moreover, the transient behavior of the pumps in their initial states of startup and final states of shutoff phases has not been studied numerically. This paper aims to develop a coupled procedure for calculating the transient inlet flow rate as a part of the solution via application of the control volume method for linear momentum. Large eddy simulation of a four-blade axial hydraulic pump is carried out to calculate the forces at every time step. The sharp interface immersed boundary method is used to resolve the flow around the complex geometry of the propeller, stator and the pipe casing. The effect of the spurious pressure fluctuations, inherent in the sharp interface immersed boundary method, is damped by local time-averaging of the forces. The developed code is validated by comparing the steady-state volumetric flow rate with the experimental data provided by the pump manufacturer. The instantaneous and time-averaged flow fields are also studied to reveal the flow pattern and turbulence characteristics in the pump flow field.
Design/methodology/approach
The authors use control volume analysis for linear momentum to simulate the discharge rate as part of the solution in a large eddy simulation of an axial hydraulic pump. The linear momentum balance equation is used to update the inlet flow rate. The sharp interface immersed boundary method with dynamic Smagorinsky sub-grid stress model and a proper wall model is used.
Findings
The steady-state volumetric flow rate has been computed and validated by comparing to the flow rate specified by the manufacturer at the simulation conditions, which shows a promising result. The instantaneous and time averaged flow fields are also studied to reveal the flow pattern and turbulence characteristics in the pump flow field.
Originality/value
An approach is proposed for computing the volumetric flow rate as a coupled part of the flow solution, enabling the simulation of turbomachinery at all phases, including the startup/shutdown phase. To the best of the authors’ knowledge, this is the first large eddy simulation of a hydraulic pump to calculate the transient inlet flow rate as a part of the solution rather than specifying it as a fixed boundary condition. The method serves as a numerical framework for simulating problems incorporating complex shapes with moving/stationary parts at all regimes including the transient start-up and shut-down phases.
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Vahid Mohamad Taghvaee, Abbas Assari Arani, Mehrab Nodehi, Jalil Khodaparast Shirazi, Lotfali Agheli, Haji Mohammad Neshat Ghojogh, Nafiseh Salehnia, Amir Mirzaee, Saeed Taheri, Raziyeh Mohammadi Saber, Hady Faramarzi, Reza Alvandi and Hosein Ahmadi Rahbarian
This study aims to assess and decompose the sustainable development using the 17 sustainable development goals (SDGs) in Iran in 2018, for proposing agenda-setting of public…
Abstract
Purpose
This study aims to assess and decompose the sustainable development using the 17 sustainable development goals (SDGs) in Iran in 2018, for proposing agenda-setting of public policy.
Design/methodology/approach
It ranks the SDGs not only in Iran but also in the region and the world to reveal the synergetic effects.
Findings
Based on the results, subaltern-populace generally suffers from the hegemonic domination of ruling elite-bourgeois, lack of strong institutions, heterogeneous policy networks and lack of advocacy role of non-governmental organizations, due to no transparency, issues in law or no rule of law, no stringent regulation, rent, suppression and Mafia, all leading to corruption and injustice.
Practical implications
To stop the loop of corruption-injustice, Iran should homogenize the structure of the policy network. Furthermore, the failed SDGs of the three-geographic analysis are the same in a character; all of them propose SDG 3, good health and well-being as a serious failed goal.
Social implications
In this regard, strong evidence is the pandemic Coronavirus, COVID 19 since 2019, due to its highly-disastrous consequences in early 2020 where the public policymakers could not adopt policies promptly in the glob, particularly in Iran.
Originality/value
In Iran, in addition to this, the malfunction of health is rooted in “subjective well-being” and “traffic deaths,” respectively. Concerning the transportations system in Iran, it is underscored that it is damaging the sustainable development from all the three pillars of sustainable development including, economic, social and environmental.
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Amir Amjad Mohammadi, Hadi Safaeipour, Mohammad Reza Chenaghlou, Alireza Behnejad and Roham Afghani Khoraskani
This paper aims at discovering the traditional techniques of Persian architecture for covering large-span spaces with a kind of ribbed vault titled “Karbandi”. This structure is…
Abstract
Purpose
This paper aims at discovering the traditional techniques of Persian architecture for covering large-span spaces with a kind of ribbed vault titled “Karbandi”. This structure is generated by intersecting several arches with a harmonic stellar geometry. Preliminary studies show that span factor affects the structural form of karbandi and large-span cases, despite similar architectural forms, have different structural systems and specific construction methods. The main focus of this paper is how karbandi has been designed and built on large-spans. To answer this question, the configuration and construction of a large-span karbandi in Tabriz Bazaar were recognized.
Design/methodology/approach
Data collection of the research was initially done in three parallel directions through the archival study of restoration documents, direct observation of the corpus of the vaultings and interviews with the master mason of the Haj-Mohammad-Qoli Timche restoration team. Then by cross-referencing the gathered data, the construction process of the karbandi was simulated in Rhino 6 and Grasshoppers software and its BIM-M models were created in three levels of development: LOD300, LOD350 and LOD400. In the next step, the preliminary BIM-M models of the karbandi were presented to the interviewed mason and revised and completed based on his comments.
Findings
Analyzing the BIM models by reverse engineering, resulted in (1) Discovering a unique self-supporting masonry construction method applied for the erection of karbandi vaulting on large-spans. (2) Finding the effect of scale factor on the architectural and structural form of the karbandi vault. (3) Discovering the connection types of the karbandi vault based on the construction details.
Originality/value
Despite the wide applications of karbandi vaults throughout history, very little information of their construction techniques is available. The techniques have mostly been experientially and orally passed down from masters to apprentices and rarely been documented. The quest to design and construct a karbandi vault is therefore like solving a puzzle whose most important guide is historical cases. Due to the geometric complexity of karbandi and its ability to cover large-span spaces, solving the puzzle can lead to achieving some technical ideas for masonry cross-ribbed vaulting. A great riddle of the karbandi vaults is how to design and build them on a large span.
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Mohammad Reza Saffarian, Farzad Jamaati, Amin Mohammadi, Fatemeh Gholami Malekabad and Kasra Ayoubi Ayoubloo
This study aims to evaluate the amount of entropy generation around the NACA 0012 airfoil. This study takes place in four angles of attack of 0°, 5°, 10° and 16° and turbulent…
Abstract
Purpose
This study aims to evaluate the amount of entropy generation around the NACA 0012 airfoil. This study takes place in four angles of attack of 0°, 5°, 10° and 16° and turbulent regime. Also, the variation in the amount of generated entropy by the changes in temperature and Mach number is investigated.
Design/methodology/approach
The governing equations are solved using computational fluid dynamics techniques. The continuity, momentum and energy equations and the equations of the SST k-ω turbulence model are solved. The entropy generation at different angles of attack is calculated and compared. The effect of various parameters in the generation of entropy is presented.
Findings
Results show that the major part of the entropy generation is at the tip of the airfoil. Also, increasing the angle of attack will increase the entropy generation. Also, results show that with increasing the temperature of air colliding with the airfoil, the production of entropy decreases.
Originality/value
Entropy generation is investigated in the NACA 0012 airfoil at various angles of attack and turbulent flow using the SST turbulence model. Also, the effects of temperature and Mach number on the entropy generation are investigated.
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Dariyoush Jamshidi and Fazlollah Kazemi
One of the main challenge when launching new banking services is to overcome resistance to change so as to accelerate market acceptance. This is the case of an Islamic credit card…
Abstract
Purpose
One of the main challenge when launching new banking services is to overcome resistance to change so as to accelerate market acceptance. This is the case of an Islamic credit card (ICC). Grounded in innovation diffusion theory (IDT) and theory of reasoned action (TRA), this paper aims to study the purposes and empirically tests an integrated model to explore, which factors influence of ICC.
Design/methodology/approach
Partial least squares and structural equation modeling was used to assess the hypotheses. Accordingly, the empirical results, obtained in a sample of 762 bank customers.
Findings
Intentions to use of ICC are mostly determined by relative advantage, compatibility, customer awareness, satisfaction and attitude. The combination of IDT and TRA significantly explain the ICC adoption.
Originality/value
This research has provided a theoretical understanding of the ICC adoption determinants with the intent of promoting a more in-depth understanding of various elements influencing acceptance and usage of this Islamic banking service.
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Abhisheck Kumar Singhania and Nagari Mohan Panda
The study aims to investigate the mediation effect of the Audit Committee’s (AC) effectiveness on the relationship between knowledge intensity and firm performance (FP) by…
Abstract
Purpose
The study aims to investigate the mediation effect of the Audit Committee’s (AC) effectiveness on the relationship between knowledge intensity and firm performance (FP) by considering the disparate effect of each AC characteristic on its effectiveness.
Design/methodology/approach
The study uses the partial least squares-structural equation model (PLS-SEM) to weigh the AC characteristics for its effectiveness and analyzes the relationships between the variables included in the models. Data was collected from authentic sources for 133 National Stock Exchange (NSE)-listed companies in six industries covering the period 2016 to 2020.
Findings
The results indicate that eight out of eleven AC characteristics, namely, nonexecutive directors, independence, expertise, AC-charter, multiple directorships, frequency of AC meetings, attendance of AC meetings and board meetings by AC directors, significantly influence the AC effectiveness while mediating the relationship between knowledge intensity and FP. Further, each characteristic of AC has a disparate effect on AC effectiveness depending on the measurement context.
Research limitations/implications
Apart from guiding the policymakers, management and stakeholders to effectively use AC characteristics in enhancing FP, this study further contributes to the literature by providing a new way to weight AC characteristics based on their individual contributions; and exploring new path models to analyze the multidimensional effect of various AC characteristics.
Originality/value
To the best of the authors’ knowledge, the study is the first to examine the mediation role of AC effectiveness on the relationship between the knowledge intensity of the firms and their performance. It demonstrates improvisation in measuring AC effectiveness using the disparate weights for each AC characteristic, computed based on their relative contribution to AC effectiveness.
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The main purpose of the current study was to develop a new research model in the hope of providing a further understanding of Digital Taxation Information Systems (DTIS) usage and…
Abstract
Purpose
The main purpose of the current study was to develop a new research model in the hope of providing a further understanding of Digital Taxation Information Systems (DTIS) usage and its impact on tax compliance by investigating the mediating role of trust in e-government services (TIE) and the moderating role of awareness (AW) toward these systems.
Design/methodology/approach
A quantitative research method approach with Partial Least Squares-Structural Equation Modelling (PLS-SEM) was employed to analyze the data collected.
Findings
The results indicated that DTIS usage is influenced by perceived usefulness (PU), perceived ease of use (PEU), attitude (ATT), knowledge (KN), subjective norm (SN), AW and TIE. Contrary to what is expected, AW does not moderate the association between SN and DTIS usage. Eventually, the results also revealed that TIE has mediated the association between trust in government (TIG) and DTIS usage.
Originality/value
This study provides thought-provoking empirical pieces of evidence about understanding the situation of DTIS usage and its impact on tax compliance among academic professors in Jordan. Furthermore, the study outcomes and discussion presented will help the Jordanian government improve and comprehensively formulate strategies to increase the tax compliance procedure.
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Ahshan Habib, Md. Feroz Khan, Md. Nasir Mia and Rokibul Hasan Sakib
The purpose of this study is to scrutinize the extent of forward-looking (FL) disclosures and explore the impact of corporate governance (CG) on FL disclosures in integrated…
Abstract
Purpose
The purpose of this study is to scrutinize the extent of forward-looking (FL) disclosures and explore the impact of corporate governance (CG) on FL disclosures in integrated reporting (IR) in the context of the banking industry in Bangladesh.
Design/methodology/approach
Twenty-two listed banks in the Dhaka Stock Exchange (DSE) are selected as a sample from 2018 to 2022. For content analysis purposes, the study has developed an unweighted self-constructed disclosure index with 58 items and extracted data manually from the integrated annual report. Furthermore, descriptive statistics is conducted to analyze the extent of FL disclosures, and a pooled ordinary least squares regression model is used to examine the impact of CG (directors’ ownership, institutional ownership, foreign ownership, board of directors, independent directors, female directors and audit quality) on the FL disclosures.
Findings
This study reveals that the banking industry’s average FL disclosure score is only approximately 43%, indicating a meager degree of disclosures in Bangladesh’s well-structured sector. This study also finds that directors’ ownership, foreign ownership, female directors and audit quality have a statistically significant and positive relationship with FL disclosures at a 5% significance level. By contrast, institutional directors and the board of directors have a substantial but negative impact on FL disclosures. However, the other exponential variable, independent directors, has no impact on FL disclosures.
Research limitations/implications
This study has some limitations, such as: i) the sample size is restricted to 22 banks, whereas nearly 36 banks are listed in the DSE. The sample size should be increased for better results. ii) The study only considers the banking sector with a small sample, but other sectors have been omitted from the sample. iii) The data have been extracted from the annual report, but other relevant sources such as banks’ websites, prospectuses, press releases, and media releases are not considered. iv) Finally, the self-constructed unweighted disclosure index is affected by subjective judgment. For depth analysis, a weighted method for content analysis purposes will be applicable.
Practical implications
Since there is no specific guideline for FL disclosures, this study suggests that the practical implication is for the regulatory body and policymakers to take the initiative to design a framework for FL disclosures that will improve disclosure quality. Second, they can investigate the independent director’s role in the banking sector to discover the existence of old-boy network problems.
Social implications
Investors will benefit from the proper judgment about the firm’s forward-looking disclosures, hence making effective decisions.
Originality/value
To the best of the authors’ knowledge, no particular study has been conducted on CG mechanisms and FL disclosures in the IR perspective of the banking sector in Bangladesh. So, this study may contribute to the existing literature.
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Mohammad Farahmand-Mehr and Seyed Meysam Mousavi
The purpose of this study is to investigate resource-constrained multi-project scheduling problems (RCMPSP) involving uncertainty in the form of time-dependent renewable resource…
Abstract
Purpose
The purpose of this study is to investigate resource-constrained multi-project scheduling problems (RCMPSP) involving uncertainty in the form of time-dependent renewable resource reliability. A key focus is to minimize the makespan (completion time) of projects when resources can become unavailable or fail over time at non-constant rates. Accounting for realistic resource reliability seeks to provide scheduling solutions that better reflect potential delays in practical multi-project environments.
Design/methodology/approach
A new discrete-time binary integer programming formulation of RCMPSP is expanded to include time-dependent resource reliability and simultaneously evaluate the time-dependent failure rate and constant repair rate of a resource. A new hybrid immune genetic algorithm with local search (HIGALS) is developed to solve this NP-hard problem. HIGALS incorporates a new coding mechanism, initialization method and local search operator.
Findings
A case study tests the proposed HIGALS approach. The validity of the mathematical model is confirmed by solving small-sized problems with GAMS software. The proposed HIGALS algorithm is validated by solving small-sized problems and comparing its solutions with GAMS. The superiority of HIGALS is demonstrated by comparing its solutions with six basic algorithms on medium- and large-sized problems. Results show that HIGALS outperforms existing algorithms, achieving an average reduction in makespan of over 11.79%, while maintaining the advantages of genetic, immune and local search algorithms and avoiding their disadvantages.
Practical implications
Considering time-dependent resource reliability can help project managers plan for disruptions and delays in resource-critical projects. HIGALS provides decision support for robust multi-project scheduling.
Originality/value
This study contributes to the field by investigating RCMPSP with time-dependent renewable resource reliability, which reflects real-world uncertainty more accurately. HIGALS presents a novel approach to balance intensification and diversification for this challenging problem.
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Hossein Mollashahi, Mohammad Bagher Fakhrzad, Hasan Hosseini Nasab and Hassan Khademi Zare
Nowadays, the topic of supply chain network design has gained significant attention as a critical area within the field of supply chain management. Researchers have dedicated…
Abstract
Purpose
Nowadays, the topic of supply chain network design has gained significant attention as a critical area within the field of supply chain management. Researchers have dedicated their studies to exploring market competitiveness and pursuing greater benefits. This paper presents a multi-objective mathematical model aimed at designing a competitive and sustainable closed-loop supply chain network specifically for perishable products. The proposed model takes into account the competition between two supply chains, considering various factors such as environmental impacts, social performance and resilience.
Design/methodology/approach
To address the competitive nature of this model, this study introduces a two-stage approach. In the initial stage, this study uses a game theory approach to determine equilibrium values for competitive decisions. This allows establishing a fair and balanced playing field between the two supply chains. Subsequently, due to the complexity of the proposed model, this study uses a multi-objective metaheuristic algorithm based on the Non-dominated Sorting Genetic Algorithm. This algorithm serves as a robust computational tool to effectively solve the network design problem and optimize the desired objectives.
Findings
To evaluate the effectiveness of the proposed model and solution approach, this study provides a numerical example. Through graphical and statistical analysis, this study assesses the performance of the model and its ability to achieve the desired objectives. The results and charts obtained demonstrate the strong performance and efficacy of the proposed model in effectively addressing the challenges associated with designing a competitive and sustainable closed-loop supply chain network for perishable products.
Research limitations/implications
By considering the various factors at play and incorporating them into the model, this study aims to contribute to the existing body of knowledge in supply chain management. The findings provide valuable insights into designing supply chain networks that not only enhance competitiveness but also promote sustainability.
Originality/value
This study represents one of the initial investigations into the evaluation of competitive supply chains, taking into account crucial factors such as environmental, social and resilience. A supply chain that considers these factors can attain greater durability and competitiveness compared to other supply chains.