Recent publications in Engineering
The continued adaptation of light-emitting diodes (LEDs) presents challenges for heat dissipation. LEDs are considered to be high power density devices, as such effective thermal management is imperative for extended usage. In this study, new design considerations such as adapting middle fin, fin height gradient towards the centre of the heat sink, along with fin perforations and a spiral cut out of the central pillar have been incorporated into heat sinks to assist convection. The heat sinks were manufactured out of aluminium alloy (AlSi10Mg) using the selective laser melting (SLM) method. The effects of orientation on the heat transfer of different heat sink geometries were experimentally studied under natural convection conditions. The performance of six different geometries with 6, 8 and 10 long fins (6LF, 8LF and 10LF) with and without middle fins were evaluated under three different heat flux conditions (471.57 , 943.14 and 1257.52 ) for 10 different orientation angles (0-90). The higher fin density heat sinks are found to have lower orientation dependency. The convective fluid flow of the higher fin density geometries is significantly hindered by the overlapping of thermal boundary layers. The increase in the Rayleigh number has the most significant effect on the 6LF heat sink. The overall Nusselt number correlations for the 6LF, 8LF and 10LF heat sinks with short fins are and , respectively. Removing short fins improved heat transfer rate for all heat sinks.
Dong, Liqiang, Lin, Wenxian, and Khatamifar, Mehdi (2021) Experimental study on the intrusion and stratification produced by confined laminar and turbulent round fountains. International Journal of Heat and Fluid Flow, 89. 108785. pp. 1-26.
In this paper, high-speed cameras and flow visualization techniques are used to investigate the behavior of the ‘fountain filling box’ flow resulted from releasing a round fountain in a homogeneous quiescent fluid in a cylindrical container over the ranges of 1.0⩽Fr⩽20.0,102⩽Re⩽1502, and 27.9⩽λ⩽48.75, where Fr,Re and λ are the Froude number, the Reynolds number, and the dimensionless radius of the container, respectively, with λ non-dimensionalized by the fountain source radius. The results show the transition of the flow behavior of the fountain and its secondary flows (i.e., the intrusion, reversed flow and stratification) from laminar to turbulent with increasing Fr, and turbulence of the flow strengthened with increasing Re. For intermediate (e.g., Fr=3.0) and forced turbulent fountains (e.g., Fr=5.0, 8.0, 15.0) with a specific λ, the non-dimensionalized time-scale for the intrusion front to impinge upon the sidewall, τw, is nearly constant for Re≳500. This is because the secondary intrusion flow is dominated by the wall-jet and buoyancy-inertial regimes where the non-dimensionalized intrusion front velocity, vi, is only time-dependent (vi~τ-1/2) or time-dependent but also under the influence of Fr (vi~Fr-1/2τ-1/4). However, τw for the fountains of Re≲204 is significantly different, which may result from the change in the dominant regime for the intrusion or the interaction between the upflow, downflow of the fountain and the ambient fluids. Furthermore, it is found that the non-dimensionalized quasi-steady development rate of the stratification, vs, increases with Fr, but decreases with Re, since the diffusion effect is suppressed with decreasing Fr or increasing Re.
Steinemann, Anne, Nematollahi, Neda, Rismanchi, Behzad, Goodman, Nigel, and Kolev, Spas D. (2021) Pandemic products and volatile chemical emissions. Air Quality, Atmosphere and Health, 14. pp. 47-53.
The recent pandemic (COVID-19) has seen a sweeping and surging use of products intended to clean and disinfect, such as air sprays, hand sanitizers, and surface cleaners, many of which contain fragrance. However, exposure to fragranced cleaning products has been associated with adverse effects on human health. Products can emit a range of volatile chemicals, including some classified as hazardous, but relatively few ingredients are disclosed to the public. Thus, relatively little is known about the specific emissions from these products. This study investigates the volatile organic compounds (VOCs) emitted from "pandemic products" that are being used frequently and extensively in society. In addition, among these emissions, this study identifies potentially hazardous compounds, compares so-called green and regular versions of products, and examines whether ingredients are disclosed to the public. Using gas chromatography/mass spectrometry, 26 commonly used pandemic products, including 13 regular and 13 so-called green versions, were analyzed for their volatile emissions. Product types included hand sanitizers, air disinfectants, multipurpose cleaners, and handwashing soap. All products were fragranced. The analyses found the products collectively emitted 399 VOCs with 127 VOCs classified as potentially hazardous. All products emitted potentially hazardous compounds. Comparing regular products and green products, no significant difference was found in the emissions of the most prevalent compounds. Further, among the 399 compounds emitted, only 4% of all VOCs and 11% of potentially hazardous VOCs were disclosed on any product label or safety data sheet. This study reveals that pandemic products can generate volatile emissions that could pose risks to health, that could be unrecognized, and that could be reduced, such as by using fragrance-free versions of products.
Wheatley, Greg, and Rubel, Robiul Islam (2021) Analysis of conveyor drive power requirements in the mining industry. Acta Logistica, 8 (1). pp. 37-43.
This article presents the analysis of conveyor drive power requirements for three typical mining conveyors. One of the conveyors was found not to be able to start when fully loaded. The analysis indicates that two of the conveyors are adequately powered while one is underpowered. This was found to be primarily the result of the maximum tonnage of the two adequately powered conveyors being 1500 tonnes per hour (TPH) while the inadequately powered conveyor was classed with a maximum tonnage of 1800 TPH. It is recommended that the current draw for each motor when fully loaded be measured. This will be compared to the design. Further analysis was done to allow 2000 TPH on all conveyors. The required upgraded drive size is presented. This article does not address the structural adequacy of the supporting structure. Rather, only the capabilities of the conveyor belt and drives to transport the required TPH.
Vuppaladadiyam, Arun K., Antunes, Elsa, Sanchez, Paula Blanco, Duan, Huabo, and Zhao, Ming (2021) Influence of microalgae on synergism during co-pyrolysis with organic waste biomass: a thermogravimetric and kinetic analysis. Renewable Energy. (In Press)
The synergistic influence of microalgae on the two forms of organic waste biomasses, namely biomass wastes (BW) and its digested form (DBW), during co-pyrolysis was evaluated based on the thermal decomposition behaviour, gas yields, extent of thermal decomposition and reaction kinetics. The biomasses and their blends were co-pyrolysed at three different heating rates (10, 15 and 20C/min) in a thermogravimetric analyzer coupled with a mass spectrometer. Initial assessment, based on TG-DTG data, revealed that the thermal degradation can be divided into three zones (50-150C, 150-550C and 550-800C) for all the biomasses and their blends. The thermogravimetric data was used to evaluate the kinetic triplet, which include apparent activation energy (Ea), pre-exponential factor (A) and reaction mechanism, f(a). Semi-quantitative method was used to quantify the gas species, H2, CO2 and CO were dominant species, implying the water gas reactions and oxidation reactions were predominant. The synergistic influence of microalgae was clearly evident in terms of reaction kinetics, as noted in the reduction in the apparent activation energy and increase in the total gas yields. The obtained kinetic triplet and thermodynamic parameters are expected to facilitate the design and optimization of co-pyrolysis of microalgae with other forms of organic wastes.
Varsha, S.S.V., Vuppaladadiyam, Arun K., Shehzad, Farrukh, Ghaedi, Hosein, Murugavelh, S., Dong, Weiguo, and Antunes, Elsa (2021) Co-pyrolysis of microalgae and municipal solid waste: a thermogravimetric study to discern synergy during co-pyrolysis process. Journal of the Energy Institute, 94. pp. 29-38.
Synergism during the co-pyrolysis of microalgae (CC), municipal solid waste (MSW), and their blends(CC/MSW) (w/w %), 25/75 (CM-1), 50/50 (CM-2), and 75/25 (CM-3), was evaluated based on thermal decomposition pattern, evolved gases, rate and extent of thermal decomposition, and kinetic parameters. Three stages of devolatilization attributed to dehydration, devolatilization of major structural com-pounds of biomass and decomposition of solid residues were noticed during the co-pyrolysis of biomass samples. The main pyrolysis stages for CC, MSW, CM-1, CM-2 and CM-3 were 175e520, 151-523, 164-504,168-510, 160e501 °C, respectively. Microalgae, CC, appeared to be thermally resistant, while MSW is noticed to be thermally sensitive. The kinetics analysis was studied by deconvoluting the DTG profile into independent stages, followed by application of isoconversional methods to evaluate the activation energy and the pre-exponential factor. Furthermore, the reaction mechanism of each stage was determined by using the master plot method. The semi-quantitative method was used to evaluate the evolved gases and CO, CO2 and H2 were noticed to be the dominant gas species. The obtained thermal and kinetic data for co-pyrolysis of microalgae and MSW can serve are basis for scale-up and reactor design of pyrolysis process for similar kind of waste streams.
Khakbaz, Hadis, Ruberu, Kalani, Kang, Lingzhi, Talebian, Sepehr, Sayyar, Sepidar, Filippi, Benjamin, Khatamifar, Mehdi, Beirne, Stephen, and Innis, Peter C. (2021) 3D printing of highly flexible, cytocompatible nanocomposites for thermal management. Journal of Materials Science, 56. pp. 6385-6400.
Highly flexible biocompatible materials that are both thermally conductive and electrically insulating are important for implantable and wearable bioelectronics applications. The ability to thermally process these materials into useful structures using additive manufacturing approaches opens up new opportunities for its use in bespoke structures. Here we investigate the three-dimensional (3D) printing of a medical-grade thermoplastic polyurethane (PU) elastomer, which is thermally insulating and enhance its thermal and mechanical properties through the incorporation of boron nitride (BN) as a filler. Via a simple solution compounding approach, a highly flexible and thermally conductive BN nanoparticle/ PU composite has been developed and subsequently processed into simple bio-scaffolds structures via a 3D pneumatic melt extrusion printing process. The addition of up to 20% w/w of BN to the PU significantly enhances the tensile modulus by 659%, from 1.74 to 13.2 MPa, while supporting high mechanical flexibility. The thermal conductivity of 20% w/w BN/PU composite increases by 74% with respect to the unmodified PU. The 3D printed BN/PU composite scaffolds exhibit good biocompatibility and cell attachment enhancement with L929 fibroblast cells.
Islam, Md Anwarul, Jacob, Mohan V., and Antunes, Elsa (2021) A critical review on silver nanoparticles: from synthesis and applications to its mitigation through low-cost adsorption by biochar. Journal of Environmental Management, 281. 111918.
Silver nanoparticles are one of the most beneficial forms of heavy metals in nanotechnology applications. Due to its exceptional antimicrobial properties, low electrical and thermal resistance, and surface plasmon resonance, silver nanoparticles are used in a wide variety of products, including consumer goods, healthcare, catalysts, electronics, and analytical equipment. As the production and applications of silver nanoparticles containing products increase daily, the environmental pollution due to silver nanoparticles release is increasing and affecting especially the aqueous ecosystem. Silver nanoparticles can kill useful bacteria in soil and water, and bioaccumulate in living organisms even at low concentrations from 10−² to 10 μg/mL silver can show antibacterial effect. On the other hand, the maximum silver discharge limit into freshwater is 0.1 μg/L and 3.2 μg/L for Australia and the USA, respectively. To reduce its toxic consequences and meet the regulatory guidelines, it is crucial to remove silver nanoparticles from wastewater before it is discharged into other water streams. Several technologies are available to remove silver nanoparticles, but the adsorption process using low-cost adsorbents is a promising alternative to mitigate silver nanoparticle pollution in the bulk stage. As one of the low-cost adsorbents, biochar produced from the biomass waste could be a suitable adsorbent. This review focuses on collating the latest evidence on silver nanoparticle production, applications, environmental consequences, and cost-effective technological approaches for silver removal from wastewater.
Belson, Bruce, Xiang, Wei, Holdsworth, Jason, and Philippa, Bronson (2021) C++20 coroutines on microcontrollers - what we learned. IEEE Embedded Systems Letters, 13 (1). pp. 9-12.
Coroutines will be added to C++ as part of the C++20 standard. Coroutines provide native language support for asynchronous operations. This study evaluates the C++ coroutine specification from the perspective of embedded systems developers. We find that the proposed language features are generally beneficial but that memory management of the coroutine state needs to be improved. Our experiments on an ARM Cortex-M4microcontroller evaluate the time and memory costs of coroutines in comparison with alternatives, and we show that context switching with coroutines is significantly faster than with thread-based real time operating systems. Furthermore, we analysed the impact of these language features on prototypical IoT sensor software. We find that the proposed language enhancements potentially bring significant benefits to programming in C++ for embedded computers, but that the implementation imposes constraints that may prevent its widespread acceptance among the embedded development community.
Timbs, Kalen, Khatamifar, Mehdi, Antunes, Elsa, and Lin, Wenxian (2021) Experimental study on the heat dissipation performance of straight and oblique fin heat sinks made of thermal conductive composite polymers. Thermal Science and Engineering Progress, 22. 100848.
Heat sink can effectively dissipate heat in a range of thermal applications for improved performance and reliability. Thermally conductive polymer composites show great promise in solving the overheating issue in electronic devices. This experimental study investigates the heat dissipation performance of straight and oblique fin heat sinks made of thermally conductive polymer composites under forced convection conditions over , where Re is the Reynolds number. The heat sinks were 3D printed using Ice9 Flex (carbon filled polymer), copper filled filament (polylactic acid with 80 wt% copper particles) and bronze filled filament (polylactic acid with 80 wt% bronze particles), respectively. Oblique fins were found to effectively reduce the thermal resistance of heat sinks, increase the convective heat transfer and the inner-fin velocity which results in lower pressure drop, in comparison to straight fins. The carbon-filled polymer (Ice9 Flex) heat sink was shown to have much superior heat dissipation capability compared to metal filled filament heat sinks.
Wheatley, Greg, and Popoola, Samuel (2021) Autonomous transmission control of a 2017 Yamaha Grizzly 700 all-terrain vehicle. Scientific Journal of Silesian University of Technology. Series transport, 110. pp. 183-198.
Investigation on a designed and modified standard automatic transmission for a 2017 Yamaha Grizzly All-Terrain Vehicle was carried out to allow it to be controlled remotely and autonomously while maintaining its ability to be manually operated. The vehicle is a part of a project named AutoWeed. This project aims at developing a vehicle which can be used in the Australian outback to control and eradicate weeds. Preliminary tests were conducted on the vehicle to determine the performance parameters required to replace the movement supplied by the operator. Several devices used to achieve this motion were explored. It was concluded that the Motion Dynamics HB-DJ806 - LALI10010 electromechanical linear actuator be used as a proof of concept device for this application. This device is capable of exerting 200 N at 35 mm/seconds. It has a stroke length of 50 mm and was powered by a 12V DC motor, which drew 3 amps at maximum load. Through testing, it was found that the selected actuator did not have enough stroke length to cycle through the five gears on the ATV. This error was rectified allowing the system to function as intended. To achieve a reliable design, however, the Linak LA14 actuator was purchased as a final design as it was stronger, faster and had feedback capabilities. Before procurement, the new actuator was digitally modelled using SolidWorks 2017 and 3D printed to confirm the mounting position and method. An ANSYS FEA was conducted on all the custom-made components including the actuator bracket and mounting plate to ensure reliability. The bracket model was manufactured using 3D printing from ABS. It was recommended that for reliability, the bracket should be constructed from a stronger material such as aluminium. The results gained from testing proved that the autonomous transmission system implemented was reliable and repeatable. This was justified as the system achieved a 100% success rate when cycling through gears.
Hall, Bevan, Wheatley, Greg, and Zaeimi, Mohammad (2021) On the design of the manifold for a race car. Periodica Polytechnica Mechanical Engineering, 65 (2). pp. 171-179.
This paper involves the design and construction of the intake manifold system of the FSAE car including the air shroud, air filter, throttle body, restrictor plenum, fuel injectors, fuel rail and runners. To ensure the quality, the proposed system is designed based on the FSAE rules. The design process of the intake manifold system will consist of the usual engineering processes including computer modelling, Finite Element Analysis and finally Computational Fluid Dynamics testing in order to determine the validity of the model and to tune the design in order to obtain the optimum performance out of the intake manifold system as a whole.
Khatamifar, Mehdi, Lin, Wenxian, and Dong, Liqiang (2021) Transient conjugate natural convection heat transfer in a differentially-heated square cavity with a partition of finite thickness and thermal conductivity. Case Studies in Thermal Engineering, 25. 100952.
The transient conjugate natural convection heat transfer in a differentially-heated cavity with a partition of finite thickness and thermal conductivity are investigated numerically over the range of the Rayleigh number from 103 to 108, the thermal conductivity ratio of partition to that of fluid from 0.1 to 1000, and the dimensionless partition thickness from 0.05 to 0.2. An analysis of the obtained temperature contours and profiles, the time for the onset of stratification and the Nusselt number shows that the thermal conductivity ratio effect is significant only over the range of 0.1–10, when the role played by the partition changes, whereas the effect becomes negligible as the thermal conductivity ratio is very large (100 or beyond). It is also found that the scaling relations developed for the non-partitioned cavity are found to be applicable for the partitioned cavity. The results further show that the effect of the partition thickness on heat transfer is significant mainly when the thermal conductivity ratio is small.
Tuladhar, Rabin, Marshall, Amelia, and Sivakugan, Siva (2020) Use of recycled concrete aggregate for pavement construction. In: Pacheco-Torgal, Fernando, Ding, Yining, Colangelo, Francesco, and Tuladhar, Rabin, (eds.) Advances in Construction and Demolition Waste Recycling: Management, Processing and Environmental Assessment. Woodhead Publishing . Elsevier, Duxford, United Kingdom, pp. 181-197.
Construction and demolition (C&D) wastes comprise waste generated from construction, renovation, and demolition of buildings, roads, and other infrastructures, and excavation of land associated with construction activities (QDERM, 2011). C&D wastes include a wide range of different waste materials such as concrete, asphalt, bricks, tiles, timber, steel, and soil. In 2016/2017, 20.4 Mt of C&D wastes were produced in Australia, which accounts for more than 40% of Australia’s total annual waste (Pickin et al., 2018). Hydraulically bound materials are made by mixing aggregates and granular aggregates with cement as a binding material. On the other hand, unbound pavement materials consist of quarry materials, natural gravels, and recycled materials without the use of binding materials like cement. Unbound granular materials are the most commonly used material for base/subbase construction in Australia owing to their strength, ease in construction, and low cost. Traditionally, natural crushed rocks are used as granular unbound material for road base and subbase constructions. With the increasing scarcity of natural aggregates and the need to reduce the waste going into landfills, alternative sustainable materials such as recycled C&D wastes are increasingly being considered as a substitute for natural aggregates.
Bodhinayake, G.G., Ginger, J.D., and Henderson, D.J. (2020) Net cladding pressures on industrial building roofs. In: Lecture Notes in Civil Engineering (37) pp. 1077-1085. From: ACMSM25: 25th Australasian Conference on Mechanics of Structures and Materials, 4-7 December 2018, Brisbane, QLD, Australia.
The net wind pressure on roof cladding of metal clad buildings are critical for structural design. Large openings on the windward wall generate large positive internal pressure, which in combination with high external suction pressure produces large net negative pressure on the roof. Wind tunnel studies conducted on a 1:200 scale industrial building model and analytical methods were used to analyze combination effects of internal and external pressures on roof cladding. AS/NZS 1170.2 gives conservative net pressures on the windward roof edge of buildings, for quartering approach wind. The combination factor ( f_C= C_(p ̌,net)/(C_(p ̌e)- C_(p ̂i) )) varies depending on location of the cladding element and position and type of opening(s) in the envelope. The calculated f_C factors are 5% less than the combination factor in the AS/NZS 1170.2 for roof cladding of nominally sealed buildings while it is 5% to 10% less than the building with the large opening. Helmholtz resonance occurs in the building with large opening and internal pressure influences energy contained in the net pressure at the Helmholtz frequency. External suction pressures on windward roof edge and positive internal pressures in the building with large windward wall opening are negatively correlated whilst of external and internal pressures are positively correlated, in the nominally sealed building
Brice, Sara M., Phillips, Elissa J., Millett, Emma L., Hunter, Adam, and Philippa, Bronson (2020) Comparing inertial measurement units and marker-based biomechanical models during dynamic rotation of the torso. European Journal of Sport Science, 20 (6). pp. 767-775.
Inertial measurement units (IMUs) enable human movements to be captured in the field and are being used increasingly in high performance sport. One key metric that can be derived from IMUs are relative angles of body segments which are important for monitoring form in many sports. The purpose of this study was to a) examine the validity of relative angles derived from IMUs placed on the torso and pelvis; and b) determine optimal positioning for torso mounted sensors such that the IMU relative angles match closely with gold standard torso-pelvis and thorax-pelvis relative angle data derived from an optoelectronic camera system. Seventeen adult participants undertook a variety of motion tasks. Four IMUs were positioned on the torso and one was positioned on the pelvis between the posterior superior iliac spines. Reflective markers were positioned around each IMU and over torso and pelvis landmarks. Results showed that the IMUs are valid with the root mean square errors expressed as a percentage of the angle range (RMSE%) ranging between 1% and 7%. Comparison between the IMU relative angles and the torso-pelvis and thorax-pelvis relative angles showed there were moderate to large differences with RMSE% values ranging between 4% and 57%. IMUs are highly accurate at measuring orientation data; however, further work is needed to optimize positioning and modelling approaches so IMU relative angles align more closely with relative angles derived using traditional motion capture methods.
Kumar, Avishek, Al-Jumaili, Ahmed, Prasad, Karthika, Bazaka, Kateryna, Mulvey, Peter, Warner, Jeffrey, and Jacob, Mohan (2020) Pulse plasma deposition of Terpinen-4-ol: an insight into polymerization mechanism and enhanced antibacterial response of developed thin films. Plasma Chemistry and Plasma Processing, 40. pp. 339-355.
Antifouling/antibacterial coating derived from a sustainable natural resource for biomedical devices have shown promising outcomes, especially in the prevention of bacterial growth. Herein, pulse-plasma chemical vapour deposition is used to fabricate antimicrobial coatings from Terpinen-4-ol, a tea tree oil-based precursor. In this manuscript, during RF plasma polymerisation, pulsed plasma is used to retain the pristine monomer structure in the developed stable coating and thereby enhance its antibacterial activity. The developed films have tunable physical and chemical properties. Diverse film surface properties were obtained by varying the plasma deposition parameters, mainly the deposition mode (pulse and continuous wave) and duty cycle. The role of film wettability on degree of bacterial attachment has been elucidated. Overall, the number of viable bacteria on all the deposited coatings (25-30%) were reduced to half with respect to the control (56%).
Al Nahain, Abdullah, Ignjatovic, Vera, Monagle, Paul, Tsanaktsidis, John, Vamvounis, George, and Ferro, Vito (2020) Anticoagulant heparin mimetics via RAFT polymerization. Biomacromolecules, 21 (2). pp. 1009-1021.
Heparin, a sulfated polysaccharide derivedfrom animal sources, is the most commonly used parenteralanticoagulant drug, but it suffers from significant safety andsupply issues. Herein, we describe the preparation of heparinmimetic homo- and copolymers via the reversible addition−fragmentation chain transfer (RAFT) polymerization in waterof commercially available (non-carbohydrate) sulfonated andcarboxylated monomers. The anticoagulant activities of thepolymers were assessed by activated partial thromboplastintime (APTT), thrombin clotting time (TCT), and for the more promising polymers, thrombin generation, antifactor Xa, andantifactor IIa assays. Sulfonated homopolymers studied herein displayed low cytotoxicity and significant anticoagulant activity inAPTT, TCT, and thrombin generation assays. In addition, copolymers of sodium styrenesulfonate and acrylic acid [poly(SSS-co-AA)] displayed unprecedented antifactor IIa activity. This study demonstrates the potential of RAFT polymers as lternativeanticoagulants for biomedical applications.
Zhang, Yufei, Zhang, Na, Chen, Jin, Zhang, Tiezhu, Ge, Wenqing, Zhang, Weimin, Xie, Gang, Zhang, Lipeng, and He, Yinghe (2020) Preparation and lithium storage properties of C@TiO₂/3D carbon hollow sphere skeleton composites. Journal of Alloys and Compounds, 815. 152511.
Rational design and facile synthesis of hybrid TiO₂ anode materials with high electrical conductivity and ionic accessibility are urgently desired to construct high performance litium-ion batteries. In this work, We first utilize conductive hollow porous pollen carbon microsphere as skeleton to load C@TiO₂ nanoparticles. The C@TiO₂/3D pollen carbon (CTPC) composite with hollow porous structure has been successfully developed via a simple method. As a result, CTPC-700 (calcination temperature of 700°C) electrode material exhibits superior electrochemical performance for lithium ion batteries, delivering an outstanding specific capacity of 148 mA h g(⁻¹) up to 1000 cycles at 5.0C and a superior high-rate performance of 112 mA h g(⁻¹) at 10.0C. Therefore, the special structure of the as-prepared composites can improve the stability of the electrode and enhance its electrochemical performance, which is promising for the next-generation of lithium-ion batteries.
Lal, Alvin, and Datta, Bithin (2020) Optimal pumping strategies for the management of coastal groundwater resources: application of Gaussian Process Regression metamodel-based simulation-optimization methodology. ISH Journal of Hydraulic Engineering. (In Press)
The present study utilizes a coupled simulation-optimization (S-O) methodology to develop a multi-objective management strategy for a coastal aquifer system. The aim of the multi-objective management model is to maximize pumping from freshwater wells (FWs) and minimize pumping from the barrier wells (BWs), while keeping salinity concentration in the aquifer within pre-specified limits (optimization constraint). To achieve computational feasibility of the management model, the numerical simulation model is substituted by the relatively new Gaussian Process Regression (GPR) metamodels. The GPR models are used to approximate coastal aquifer responses to variable transient pumping patterns from FWs and BWs. Prediction capabilities of the developed GPR metamodels are quantified using standard statistical parameters. Once trained and validated, the GPR metamodels are coupled to a multi-objective genetic algorithm optimization model and used to prescribe optimal groundwater pumping patterns. The outcomes of this study establishes the potential applicability of the GPR metamodel-based S-O model for developing sustainable coastal groundwater management strategies, which can utilize accurate and efficient prediction of management strategy impacts on the saltwater intrusion (SI) process when the optimal management policy development is based on the trained metamodel predictions. Once implemented, the developed strategy can help in controlling SI in coastal aquifer systems.
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