ORCID Profile
0000-0001-6273-7655
Current Organisations
Agri Food and Biosciences Institute
,
James Cook University
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Publisher: Elsevier BV
Date: 06-2021
Publisher: MDPI AG
Date: 05-04-2023
Abstract: The flow behavior of weak symmetric plane fountains in linearly stratified fluids is studied numerically with three-dimensional simulations over a range of the Froude (Fr), Reynolds (Re), and stratification numbers (s). The two main parameters describing the fountain characterization are the dimensionless maximum fountain penetration height (zm) and intrusion velocity (uint), which differ significantly at different flow development stages. It was found that the stratification stabilizes the symmetry of the weak fountains, which makes the fountain become asymmetric at a larger Fr value, and zm at the fully developed stage continues to increase as a result of the intrusion, which continually changes the ambient fluid stratification features, thus the buoyant force. The evolution of intrusion experiences three distinct stages. Both Fr and s have effects on zm and uint, with the effect of Fr usually larger than that of s. The overall impacts of Fr and s can be quantified in terms of Frasb, with a and b varying for different parameters. With numerical results, empirical correlations are produced in terms of Frasb for each relevant parameter, which generally predict the results very well.
Publisher: Elsevier BV
Date: 02-2017
Publisher: Elsevier BV
Date: 03-2017
Publisher: Trans Tech Publications, Ltd.
Date: 07-2016
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.846.30
Abstract: This paper presents a numerical study on the flow dynamics and heat transfer behaviour of unsteady conjugate natural convection boundary layers (CNCBLs) in a partitioned, air filled square cavity. An unsteady two-dimensional multigrid-assisted solver is developed in the C#.NET programming language on stretched Cartesian meshes. The finite volume method is used to discretise the governing equations. To solve the coupled pressure and velocity, the SIMPLE algorithm is used, and to increase simulation accuracy the Adam-Bashforth, QUICK and central difference schemes are employed for time, convection, and diffusion terms respectively. The Poisson pressure equation is solved through the use of the multigrid method. The developed code is used to model CNCBLs which typically require a large amount of simulation time. The numerical results provide detailed descriptions of unsteady CNCBLs and associated heat transfer behaviour over a wide range of Ra , such as the thermal and viscous boundary layer thicknesses, temperature and velocity distributions, and maximum velocities within the CNCBLs.
Publisher: MDPI AG
Date: 15-07-2023
DOI: 10.3390/EN16145394
Abstract: Hydropower is one of the most sustainable and desirable renewable energy sources. Gravitational water vortex hydro turbine (GWVHT) systems are one of the most suitable and sustainable renewable power generation devices for remote and rural areas, particularly in developing countries, owing to their small scales and low costs. There are various GWVHT systems with different configurations and various operating conditions. The main components of a GWVHT system include the inlet and outlet channels, a basin, and a turbine on which there are a number of blades attached. This paper presents a comprehensive review regarding the progress and development of various GWVHT systems, covering broad aspects of GWVHT systems, particularly various types of basins, inlet and outlet channels, turbines with blades which have different shapes, orientations, sizes, numbers, etc. The nature of the previous studies is summarised. The fundamentals of the vortex dynamics involved and the quantitative analysis of the performance of GWVHT systems are also described. The turbulence models and multiphase models used in some leading numerical simulation studies have been reviewed. As a case study, the implementation of a GWVHT system in PNG is presented. Based on the review of previous studies regarding GWVHT systems, the major issues and challenges are summarised, and some key topics are recommended for future research work on the performance of GWVHT systems.
Publisher: Wiley
Date: 21-12-2022
DOI: 10.1002/HTJ.22431
Abstract: The understanding of the transient behavior of the natural convection boundary layer on a heated vertical solid surface is crucial for numerous applications. In this study, scaling analysis is performed to derive the scaling laws for the major parameters that characterize the transient behavior of natural convection boundary layer of a Prandtl number larger than 1 fluid on a vertical solid surface subject to a sinusoidal heating flux in a linearly stratified ambient. It is found that the developed scaling laws are in good agreement with the direct numerical simulation results over wide ranges of Prandtl number, stratification parameter, and frequency of the sinusoidal heat flux.
Publisher: Marine Technology Society
Date: 08-06-2022
DOI: 10.4031/MTSJ.56.3.19
Abstract: Abstract The European COST Action “Unifying Approaches to Marine Connectivity for improved Resource Management for the Seas” (SEA-UNICORN, 2020‐2025) is an international research coordination initiative that unites an interdisciplinary community of scientists and policymakers from over 100 organizations across Europe and beyond. It is establishing a globally harmonized framework to deliver actionable, transdisciplinary knowledge of marine functional connectivity, promoting a sustainable blue economy and ocean conservation. Planning sustainable development in rapidly changing oceans requires a thorough comprehension of marine bio ersity and the processes underpinning the functioning of ecosystems. Connectivity among marine populations and habitats facilitates the persistence and resilience of vulnerable species and ecosystems and controls the spread of invasive species. Constructing effective networks of restoration or conservation areas and promoting sustainable harvesting requires knowledge of connectivity. SEA-UNICORN advances worldwide collaboration by coordinating the collection, sharing, and application of knowledge on species, community, and ecosystem connectivity at sea and at the land‐sea interface. It engages scientists from erse areas and early-career researchers and creates a stronger match between natural and social science and policy needs to better address key environmental issues that challenge the future of our planet.
Publisher: Wiley
Date: 24-03-2023
DOI: 10.1002/HTJ.22852
Abstract: Origami has become an increasingly popular geometry in thermal engineering, namely, heat regulatory applications such as heat sinks and radiators. In this study, the radiative heating and radiative and natural convective cooling of three origami geometries (W‐fold, Miura Ori (1), and Miura Ori (2)) made of heavy‐duty aluminum foil under a radiative heater with different powers (800, 1600, and 2400 W) and different compression lengths (0.15, 0.25, 0.35, and 0.45 m) were investigated. It was found that the Miura Ori (1) and Miura Ori (2) geometries have three to four times high‐temperature differences (the maximum temperature at the end of the heating process minus the initial temperature) than the W‐fold geometry. The Miura Ori (2) and Miura Ori (1) geometries produced high heat capacity enhancements of 1.2–3.2 times at high compression lengths that showed great potential for applications such as solar steam generators. The overall heat transfer coefficient for cooling can be controlled by changing the compression length of the origami geometry, allowing for dynamic surface temperature controls. This parameter decreases by up to 25.3%, 22.6%, and 45.9% for W‐fold, Miura Ori (1), and Miura Ori (2), respectively, in comparison to their flat states.
Publisher: Elsevier BV
Date: 10-2021
Publisher: Pensoft Publishers
Date: 22-02-2022
DOI: 10.3897/RIO.8.E80223
Abstract: Truly sustainable development in a human-altered, fragmented marine environment subject to unprecedented climate change, demands informed planning strategies in order to be successful. Beyond a simple understanding of the distribution of marine species, data describing how variations in spatio-temporal dynamics impact ecosystem functioning and the evolution of species are required. Marine Functional Connectivity (MFC) characterizes the flows of matter, genes and energy produced by organism movements and migrations across the seascape. As such, MFC determines the ecological and evolutionary interdependency of populations, and ultimately the fate of species and ecosystems. Gathering effective MFC knowledge can therefore improve predictions of the impacts of environmental change and help to refine management and conservation strategies for the seas and oceans. Gathering these data are challenging however, as access to, and survey of marine ecosystems still presents significant challenge. Over 50 European institutions currently investigate aspects of MFC using complementary methods across multiple research fields, to understand the ecology and evolution of marine species. The aim of SEA-UNICORN, a COST Action within the European Union Horizon 2020 framework programme, is to bring together this research effort, unite the multiple approaches to MFC, and to integrate these under a common conceptual and analytical framework. The consortium brings together a erse group of scientists to collate existing MFC data, to identify knowledge gaps, to enhance complementarity among disciplines, and to devise common approaches to MFC. SEA-UNICORN will promote co-working between connectivity practitioners and ecosystem modelers to facilitate the incorporation of MFC data into the predictive models used to identify marine conservation priorities. Ultimately, SEA-UNICORN will forge strong forward-working links between scientists, policy-makers and stakeholders to facilitate the integration of MFC knowledge into decision support tools for marine management and environmental policies.
Publisher: Elsevier BV
Date: 12-2021
Publisher: Elsevier BV
Date: 2011
DOI: 10.1016/J.BIORTECH.2010.09.094
Abstract: In recent years biodiesel has drawn considerable amount of attention as a clean and renewable fuel. Biodiesel is produced from renewable sources such as vegetable oils and animal fat mainly through catalytic or non-catalytic transesterification method as well as supercritical method. However, as a consequence of disadvantages of these methods, the production cost increases dramatically. This article summarizes different biodiesel production methods with a focus on their advantages and disadvantages. The downstream and upstream strategies such as using waste cooking oils, application of non-edible plant oils, plant genetic engineering, using membrane separation technology for biodiesel production, separation and purification, application of crude glycerin as an energy supplement for ruminants, glycerin ultra-purification and their consequent roles in economizing the production process are fully discussed in this article.
Publisher: Elsevier BV
Date: 10-2022
Publisher: Elsevier BV
Date: 06-2021
Publisher: Informa UK Limited
Date: 06-04-2023
Publisher: Wiley
Date: 07-09-2023
DOI: 10.1002/HTJ.22691
Abstract: A “fountain filling box” flow produced by discharging a weak laminar plane fountain in a confined open channel is studied numerically. Two‐dimensional direct numerical simulations were performed for weak plane fountains. The development of the fountain flow experiences five stages the initial upflow and the subsequent downflow after the fountain penetrates to the maximum height, followed by the outward movement of the intrusion of the fallen fountain fluid on the channel bottom, and then the wall fountain formed by the impingement of the intrusion on the vertical sidewall, which results in the reversed flow, and finally the gradual stratification of the fluid. The behavior of the intrusion can be approximately described with the plane gravity current theory. The period for the intrusion to reach the bounded side wall increases with increasing Re or decreasing Fr . Three regimes are found for the wall fountain behavior “no‐falling,” “slumping down,” and “rolling down” behavior. Convection, mixing, conduction, and filling all contribute to the formation and development of stratification, but their effects vary at different stages. For the initial stages, convection and mixing play a key role, resulting in an increasing bulk entrainment rate, while conduction and filling are dominant after quasi‐steady stratification is created, presenting a decreasing bulk entrainment rate.
Publisher: MDPI AG
Date: 18-04-2023
DOI: 10.3390/EN16083505
Abstract: Telecommunication systems have become a critical part of society which enables connectivity to many essential and trivial services. Consequently, telecommunication equipment is housed in cabinets to protect the electronics from a variety of hazards one of which is temperature-related failure. Current practices use a notable amount of power for the thermal management of telecommunication cabinets which can be reduced by considering alternative methods of cooling. In this paper, experiments were carried out to investigate the effectiveness of different internal mounting configurations of electronic components on the thermal performance of a telecommunication cabinet. The investigation tested inclinations (0–90°), different staggered offsets (0–50 mm), changing stream-wise spacing (29–108 mm), and fan speed (with a Reynolds number in the range of 1604 to 5539). The experimental study revealed that heat transfer was enhanced by 9.99% by altering component inclination to 90°, 25.90% by increasing stream-wise spacing from 29 mm to 108 mm, and 36.02% by increasing the Reynolds number from 1604 to 5539. However, the staggered arrangement of internal components decreased Nu by 3.26% for the natural convection condition but increased by 5.69% for the forced convection condition over the tested range and increasing the centre offset of the staggered components with respect to the cabinet did not influence Nu in any significant manner. Natural convection and forced convection also had notable influence on the heat transfer rate. Hence it was seen that alternative internal configurations positively influence heat transfer in telecommunication cabinets for the cases studied.
Publisher: Pensoft Publishers
Date: 22-12-2022
DOI: 10.3897/RIO.8.E98874
Abstract: Truly sustainable development in a human-altered, fragmented marine environment subject to unprecedented climate change, demands informed planning strategies in order to be successful. Beyond a simple understanding of the distribution of marine species, data describing how variations in spatio-temporal dynamics impact ecosystem functioning and the evolution of species are required. Marine Functional Connectivity (MFC) characterizes the flows of matter, genes and energy produced by organism movements and migrations across the seascape. As such, MFC determines the ecological and evolutionary interdependency of populations, and ultimately the fate of species and ecosystems. Gathering effective MFC knowledge can therefore improve predictions of the impacts of environmental change and help to refine management and conservation strategies for the seas and oceans. Gathering these data are challenging however, as access to, and survey of marine ecosystems still presents significant challenge. Over 50 European institutions currently investigate aspects of MFC using complementary methods across multiple research fields, to understand the ecology and evolution of marine species. The aim of SEA-UNICORN, a COST Action supported by COST (European Cooperation in Science and Technology), is to bring together this research effort, unite the multiple approaches to MFC, and to integrate these under a common conceptual and analytical framework. The consortium brings together a erse group of scientists to collate existing MFC data, to identify knowledge gaps, to enhance complementarity among disciplines, and to devise common approaches to MFC. SEA-UNICORN will promote co-working between connectivity practitioners and ecosystem modelers to facilitate the incorporation of MFC data into the predictive models used to identify marine conservation priorities. Ultimately, SEA-UNICORN will forge strong forward-working links between scientists, policy-makers and stakeholders to facilitate the integration of MFC knowledge into decision support tools for marine management and environmental policies.
Publisher: Elsevier BV
Date: 2009
Publisher: Elsevier BV
Date: 10-2012
Publisher: Springer Science and Business Media LLC
Date: 03-01-2021
Publisher: Elsevier BV
Date: 05-2021
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: Iran (Islamic Republic of)
Location: Iran (Islamic Republic of)
No related grants have been discovered for Mehdi Khatamifar.