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1 – 10 of 31Chandan Kumawat, Bhupendra Kumar Sharma, Taseer Muhammad and Liaqat Ali
The purpose of this study is to determine the impact of two-phase power law nanofluid on a curved arterial blood flow under the presence of ovelapped stenosis. Over the past…
Abstract
Purpose
The purpose of this study is to determine the impact of two-phase power law nanofluid on a curved arterial blood flow under the presence of ovelapped stenosis. Over the past couple of decades, the percentage of deaths associated with blood vessel diseases has risen sharply to nearly one third of all fatalities. For vascular disease to be stopped in its tracks, it is essential to understand the vascular geometry and blood flow within the artery. In recent scenarios, because of higher thermal properties and the ability to move across stenosis and tumor cells, nanoparticles are becoming a more common and effective approach in treating cardiovascular diseases and cancer cells.
Design/methodology/approach
The present mathematical study investigates the blood flow behavior in the overlapped stenosed curved artery with cylinder shape catheter. The induced magnetic field and entropy generation for blood flow in the presence of a heat source, magnetic field and nanoparticle (Fe3O4) have been analyzed numerically. Blood is considered in artery as two-phases: core and plasma region. Power-law fluid has been considered for core region fluid, whereas Newtonian fluid is considered in the plasma region. Strongly implicit Stone’s method has been considered to solve the system of nonlinear partial differential equations (PDE’s) with 10–6 tolerance error.
Findings
The influence of various parameters has been discussed graphically. This study concludes that arterial curvature increases the probability of atherosclerosis deposition, while using an external heating source flow temperature and entropy production. In addition, if the thermal treatment procedure is carried out inside a magnetic field, it will aid in controlling blood flow velocity.
Originality/value
The findings of this computational analysis hold great significance for clinical researchers and biologists, as they offer the ability to anticipate the occurrence of endothelial cell injury and plaque accumulation in curved arteries with specific wall shear stress patterns. Consequently, these insights may contribute to the potential alleviation of the severity of these illnesses. Furthermore, the application of nanoparticles and external heat sources in the discipline of blood circulation has potential in the medically healing of illness conditions such as stenosis, cancer cells and muscular discomfort through the usage of beneficial effects.
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Tian-Yu Wu, Jianfei Zhang, Yanjun Dai, Tao-Feng Cao, Kong Ling and Wen-Quan Tao
To present the detailed implementation processes of the IDEAL algorithm for two-dimensional compressible flows based on Delaunay triangular mesh, and compare the performance of…
Abstract
Purpose
To present the detailed implementation processes of the IDEAL algorithm for two-dimensional compressible flows based on Delaunay triangular mesh, and compare the performance of the SIMPLE and IDEAL algorithms for solving compressible problems. What’s more, the implementation processes of Delaunay mesh generation and derivation of the pressure correction equation are also introduced.
Design/methodology/approach
Programming completely in C++.
Findings
Five compressible examples are used to test the SIMPLE and IDEAL algorithms, and the comparison with measurement data shows good agreement. The IDEAL algorithm has much better performance in both convergence rate and stability over the SIMPLE algorithm.
Originality/value
The detail solution procedure of implementing the IDEAL algorithm for compressible flows based on Delaunay triangular mesh is presented in this work, seemingly first in the literature.
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Chris de Blok and Richard Page
Sustainable Development Goal 14 of the United Nations aims to ‘conserve and sustainably use the oceans, seas and marine resources for sustainable development’. To achieve this…
Abstract
Sustainable Development Goal 14 of the United Nations aims to ‘conserve and sustainably use the oceans, seas and marine resources for sustainable development’. To achieve this goal, we must rebuild the marine life-support systems that provide society with the many advantages of a healthy ocean. Therefore, countries worldwide have been using Marine Protected Areas (MPAs) to restore, create, or protect habitats and ecosystems. Palau was one of the first countries to use MPAs as a tool to develop biodiversity within its exclusive economic zone. On 22 October 2015, Palau placed approximately 80% of its maritime territory in a network of locally monitored MPAs, which has now shown a population increase in stationary and migratory fish species. This movement towards a MPA was intentional and because of increased pressure from tourism and the increasing incursion of foreign fishing vessels in Palauan territorial waters. Since countries worldwide are using and looking towards MPAs, secondary protection projects are becoming more and more popular. This chapter highlights the practical implementations and results in Palau, how to theoretically apply this within the Greater North Sea in combination with Windmill Farms, and how the Marine Strategy Framework Directive stimulates these practices.
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Ashish Bhatt and Shripad P. Mahulikar
Aero-engine exhaust plume length can be more than the aircraft length, making it easier to detect and track by infrared seeker. Aim of this study is to analyze the effect of free…
Abstract
Purpose
Aero-engine exhaust plume length can be more than the aircraft length, making it easier to detect and track by infrared seeker. Aim of this study is to analyze the effect of free stream Mach number (M∞) on length of potential core of plume. Also, change in infrared (IR) signature of plume and aircraft surface with variation in elevation angle (θ) is examined.
Design/methodology/approach
Convergent divergent (CD) nozzle is located outside the rear fuselage of the aircraft. A two dimensional axisymmetric computational fluid dynamics (CFD) study was carried out to study effect of M∞ on potential core. The CFD data with aircraft and plume was then used for IR signature analysis. The sensor position is changed with respect to aircraft from directly bottom towards frontal section of aircraft. The IR signature is studied in mid wave IR (MWIR) and long wave IR (LWIR) band.
Findings
The potential plume core length and width increases as M∞ increases. At higher altitudes, the potential core length increases for a fixed M∞. The plume emits radiation in the MWIR band, whereas the aerodynamically heated aircraft surface emits IR in the LWIR band. The IR signature in the MWIR band continuously decreases as the sensor position changes from directly bottom towards frontal. In the LWIR band the IR signature initially decreases as the sensor moves from the directly bottom to the frontal, as the sensor begins to see the wing leading edges and nose cone, the IR signature in the LWIR band slightly increases.
Originality/value
The novelty of this study comes from the data reported on the effect of free stream Mach number on the potential plume core and variation of the overall IR signature of aircraft with change in elevation angle from directly below towards frontal section of aircraft.
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Samille Souza Marinho, Armando Gomes Rego Neto, Reimison Moreira Fernandes, André Cristiano Silva Melo, Leonardo dos Santos Lourenço Bastos and Vitor William Batista Martins
This study aims to identify sustainability indicators in the energy sector through a literature review and validate them from the perspective and context of professionals working…
Abstract
Purpose
This study aims to identify sustainability indicators in the energy sector through a literature review and validate them from the perspective and context of professionals working in the sector in an emerging economy country, Brazil, considering the relationship of these indicators with the achievement of the targets set by the United Nations sustainable development goals (UN SDGs).
Design/methodology/approach
To accomplish this, a literature review on sustainability indicators specific to the energy sector was conducted. Subsequently, a research instrument (questionnaire) based on the identified indicators was developed and a survey was administered to professionals in the field. The collected data were analyzed using the Lawshe method.
Findings
The results revealed 20 indicators, distributed across environmental, economic and social dimensions. Among these, nine indicators were validated, including global impacts, local impacts, renewable energy production as a percentage of total production, greenhouse gas emissions, access to electricity, investment in the energy sector, installed capacity in the electricity sector, energy prices in the end-use sector and energy distribution and conversion efficiency.
Originality/value
Consequently, it was possible to determine which SDGs are directly impacted and provide a foundation for future actions that can contribute to the sustainable advancement of the energy sector in emerging countries.
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Mohammadsadegh Pahlavanzadeh, Krzysztof Rusin and Wlodzimierz Wróblewski
The purpose of this study is an assessment of the existing roughness models to simulate the flow in the narrow gap between corotating and rough disks. A specific configuration of…
Abstract
Purpose
The purpose of this study is an assessment of the existing roughness models to simulate the flow in the narrow gap between corotating and rough disks. A specific configuration of the flow through the gap, which forms a minichannel with variable cross sections and rotating walls, makes it a complex problem and, therefore, worth discussing in more detail.
Design/methodology/approach
Two roughness models were examined, the first one was based on the wall function modification by application of the shift in the dimensionless velocity profile, and the second one was based on the correction of turbulence parameters at the wall, proposed by Aupoix. Due to the lack of data to validate that specific case, the approach to deal with was selected after a systematic study of reported test cases. It started with a zero-pressure-gradient boundary layer in the flow over a flat plate, continued with flow through minichannels with stationary walls, and finally, focused on the flow between corotating discs, pertaining each time to smooth and rough surfaces.
Findings
The limitations of the roughness models were highlighted, which make the models not reliable in the application to minichannel flows. It concerns turbulence models, near-wall discretization and roughness approaches. Aupoix’s method to account for roughness was selected, and the influence of minichannel height, mass flow rate, fluid properties and roughness height on the velocity profile between corotating discs in both smooth and rough cases was discussed.
Originality/value
The originality of this study is the evaluation and validation of different methods to account for the roughness in rotating mini channels, where the protrusions can cover a substantial part of the channel. Flow behavior and performance of different turbulence models were analyzed as well.
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Huy Van Le, Le Chi Cong and Mark A.A.M. Leenders
This research aims to explore the role of awareness of harm and responsibility for environmental protection in reducing pollution from single-use plastic bags (SPBs) in coastal…
Abstract
Purpose
This research aims to explore the role of awareness of harm and responsibility for environmental protection in reducing pollution from single-use plastic bags (SPBs) in coastal communities (CCs). To this end, this study develops and tests a unique model that explains residents’ intention to reduce the use of SPBs in coastal regions.
Design/methodology/approach
A questionnaire was used to collect data from 721 coastal residents in Vietnam. Structural equation modeling and moderation analysis were applied to test the proposed hypotheses.
Findings
The results show that awareness of the impact of SPBs on the environment and human health and awareness of the responsibility to protect the coastal environment significantly affect attitudes and intentions to reduce the use of SPBs. Moreover, such awareness of responsibility strengthens the attitude-intention relationship.
Practical implications
The findings suggest that CCs should not receive a lower priority in campaigns and efforts to reduce SPBs. In this regard, providing residents with free environmentally friendly bags and education programs on the impact of SPBs could be implemented.
Originality/value
CCs are directly impacted by pollution from SPBs. However, little is known about how this affects their polluting behavior. This study shows that CCs are not immune to polluting behaviors and that SPBs can be significant among residents. It also demonstrates that awareness of harm and feeling responsible for the environment are essential drivers of (intended) sustainable behaviors.
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Leona Wiegmann, Annemarie Conrath-Hargreaves, Zhengqi Guo, Matthew Hall, Ralph Kober, Richard Pucci, Paul J. Thambar and Tirukumar Thiagarajah
The use of interviews for data collection is prevalent in qualitative accounting research. This paper examines vignettes – sketches of hypothetical scenarios – as a promising…
Abstract
Purpose
The use of interviews for data collection is prevalent in qualitative accounting research. This paper examines vignettes – sketches of hypothetical scenarios – as a promising complementary way to conduct interviews in qualitative accounting research.
Design/methodology/approach
The paper is based on our experiences designing and using vignettes in five separate qualitative accounting studies, which collectively involve over 200 interviews with various participants. It discusses the opportunities the use of vignettes in interviews offers to qualitative accounting research, as well as the challenges associated with designing and using vignettes. The paper also reflects on fellow researchers’ varied reactions during seminars, workshops, and the journal review process.
Findings
Vignettes emerge as a productive and engaging complementary way for accounting researchers to obtain additional insights and perspectives not usually accessible in semi-structured interviews. The paper also provides practical insights into developing, using and publishing qualitative accounting studies using vignettes, contributing an additional behind-the-scenes view of using qualitative research methods.
Originality/value
The aim of this paper is to increase awareness of vignettes as a complement to the standard qualitative accounting interview. It provides guidance on how vignettes might be used productively for studying rare, new, emerging, complex, or multi-period real-world accounting phenomena. It also discusses how vignettes can promote transparency, honesty, and a greater level of detail in participants’ responses, as well as facilitate the involvement of lay people in accounting studies.
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Iman Bashtani and Javad Abolfazli Esfahani
This study aims to introduce a novel machine learning feature vector (MLFV) method to bring machine learning to overcome the time-consuming computational fluid dynamics (CFD…
Abstract
Purpose
This study aims to introduce a novel machine learning feature vector (MLFV) method to bring machine learning to overcome the time-consuming computational fluid dynamics (CFD) simulations for rapidly predicting turbulent flow characteristics with acceptable accuracy.
Design/methodology/approach
In this method, CFD snapshots are encoded in a tensor as the input training data. Then, the MLFV learns the relationship between data with a rod filter, which is named feature vector, to learn features by defining functions on it. To demonstrate the accuracy of the MLFV, this method is used to predict the velocity, temperature and turbulent kinetic energy fields of turbulent flow passing over an innovative nature-inspired Dolphin turbulator based on only ten CFD data.
Findings
The results indicate that MLFV and CFD contours alongside scatter plots have a good agreement between predicted and solved data with R2 ≃ 1. Also, the error percentage contours and histograms reveal the high precisions of predictions with MAPE = 7.90E-02, 1.45E-02, 7.32E-02 and NRMSE = 1.30E-04, 1.61E-03, 4.54E-05 for prediction velocity, temperature, turbulent kinetic energy fields at Re = 20,000, respectively.
Practical implications
The method can have state-of-the-art applications in a wide range of CFD simulations with the ability to train based on small data, which is practical and logical regarding the number of required tests.
Originality/value
The paper introduces a novel, innovative and super-fast method named MLFV to address the time-consuming challenges associated with the traditional CFD approach to predict the physics of turbulent heat and fluid flow in real time with the superiority of training based on small data with acceptable accuracy.
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Performance appraisal (PA) is an organizational practice whose ultimate goal is to improve employee performance. This goal can be achieved using two approaches: the administrative…
Abstract
Purpose
Performance appraisal (PA) is an organizational practice whose ultimate goal is to improve employee performance. This goal can be achieved using two approaches: the administrative approach, which emphasizes materialistic incentives and rewards excellent performers, and the developmental approach, which focuses on employee personal and professional development. The literature points out that organizations cannot utilize both approaches at the same time, but the reason for this is vague. Therefore, the research purpose is to bridge this gap by exploring the basic assumptions behind the administrative and developmental PA approaches as part of the hidden layers of organizational culture.
Design/methodology/approach
A qualitative document analysis (QDA) was used to analyze 124 Israeli organizations' PA forms and employee reports.
Findings
The organization's PA approaches were diagnosed as a first step in revealing the reason for the inability to use both approaches simultaneously. In the next step, it was revealed that organizational culture assumptions are the reason for the contradiction of the PA approaches. Eventually, McGregor's theory X is the basic assumption behind the administrative approach, and theory Y is the assumption behind the developmental approach. Since these two approaches contradict each other, it explains the difficulty of using both approaches simultaneously.
Originality/value
This study dives into the hidden levels of organizational culture and attempts to bridge a long-standing but still current research gap, as well as extend and refine organizational culture and performance appraisal theories.
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