ORCID Profile
0000-0002-2538-4077
Current Organisations
Deakin University School of Engineering
,
Swinburne University of Technology
,
University of Malaya
,
Deakin University
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Publisher: MDPI AG
Date: 14-12-2017
DOI: 10.3390/EN10122129
Publisher: Wiley
Date: 06-03-2016
DOI: 10.1002/CPLX.21766
Publisher: Elsevier BV
Date: 04-2021
Publisher: Elsevier BV
Date: 06-2020
Publisher: Springer Science and Business Media LLC
Date: 11-01-2022
DOI: 10.1186/S13256-021-03204-7
Abstract: Acquired long QT syndrome is an important and preventable cause of cardiac arrest. Certain medications and electrolyte disturbance are common contributors, and often coexist. In this case, we report five contributors to cardiac arrest. This case is of a 51-year-old Caucasian female patient who presented with vomiting associated with hypokalemia and hypomagnesemia. She subsequently received ondansetron and metoclopramide, on the background of chronic treatment with fluoxetine. She then suffered an in-hospital monitored cardiac arrest, with features of long QT and torsades de pointes retrospectively noted on her prearrest electrocardiogram. She was diagnosed with acquired long QT syndrome, and her QT interval later normalized after removal of offending causes. This case highlights the importance of proper consideration prior to prescribing QT prolonging medications, especially in patients who have other risk factors for prolonged QT, such as electrolyte disturbances and pretreatment with QT prolonging medications.
Publisher: MDPI AG
Date: 02-03-2016
DOI: 10.3390/EN9030147
Publisher: MDPI AG
Date: 22-09-2021
DOI: 10.3390/SU131910492
Abstract: As promising solutions to various social and environmental issues, the generation and integration of renewable energy (RE) into microgrids (MGs) has recently increased due to the rapidly growing consumption of electric power. However, such integration can affect the stability and security of power systems due to its complexity and intermittency. Therefore, an optimal control approach is essential to ensure the efficiency, reliability, and quality of the delivered power. In addition, effective planning of policies for integrating MGs can help promote MG operations. However, outages may render these strategies inefficient and place the power system at risk. MGs are considered an ideal candidate for distributed power systems, given their capability to restore these systems rapidly after a physical or cyber-attack and create reliable protection systems. The energy management system (EMS) in an MG can operate controllable distributed energy resources and loads in real-time to generate a suitable short-term schedule for achieving some objectives. This paper presents a comprehensive review of MG elements, the different RE resources that comprise a hybrid system, and the various types of control, operating strategies, and goals in an EMS. A detailed explanation of the primary, secondary, and tertiary levels of MGs is also presented. This paper aims to contribute to the policies and regulations adopted by certain countries, their protection schemes, transactive markets, and load restoration in MGs.
Publisher: Wiley
Date: 10-2018
DOI: 10.1111/IWJ.13006
Publisher: Springer Science and Business Media LLC
Date: 21-01-2015
Publisher: Springer International Publishing
Date: 2018
Publisher: Elsevier BV
Date: 10-2016
Publisher: Springer International Publishing
Date: 2018
Publisher: IEEE
Date: 09-2019
Publisher: MDPI AG
Date: 10-11-2016
DOI: 10.3390/EN9110937
Publisher: Springer Science and Business Media LLC
Date: 02-04-2014
Publisher: Elsevier BV
Date: 05-2021
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2023
Publisher: MDPI AG
Date: 07-06-2018
DOI: 10.3390/EN11061491
Publisher: MDPI AG
Date: 16-05-2017
DOI: 10.3390/EN10050701
Publisher: Springer Science and Business Media LLC
Date: 10-06-2021
DOI: 10.1038/S41467-021-23805-6
Abstract: The formation of stable, evolved (silica-rich) crust was essential in constructing Earth’s first cratons, the ancient nuclei of continents. Eoarchaean (4000–3600 million years ago, Ma) evolved crust occurs on most continents, yet evidence for older, Hadean evolved crust is mostly limited to rare Hadean zircons recycled into younger rocks. Resolving why the preserved volume of evolved crust increased in the Eoarchaean is key to understanding how the first cratons stabilised. Here we report new zircon uranium-lead and hafnium isotope data from the Yilgarn Craton, Australia, which provides an extensive record of Hadean–Eoarchaean evolved magmatism. These data reveal that the first stable, evolved rocks in the Yilgarn Craton formed during an influx of juvenile (recently extracted from the mantle) magmatic source material into the craton. The concurrent shift to juvenile sources and onset of crustal preservation links craton stabilisation to the accumulation of enduring rafts of buoyant, melt-depleted mantle.
Publisher: MDPI AG
Date: 03-08-2021
DOI: 10.3390/EN14154709
Abstract: The component count for the multilevel inverter has been a research topic for the last few decades. The higher number of power semiconductor devices and sources leads to a higher power loss with the complex control requirement. A new multilevel inverter topology employing the concept of half-Bridge modules is suggested in this paper. It requires a lower number of dc sources and power components. The inverter is controlled using a fundamental frequency switching scheme. With the basic unit being able to produce 13 level voltage waveforms with three dc voltage sources, higher-level inverter configuration has also been discussed in the paper. The performance of the topology is analyzed in the aspects of circuit parameters and found better when compared to similar topologies proposed in recent literature. The comparison provided in the paper set the benchmark of the proposed topology in terms of lower component requirements. The topology is also optimized with two voltage fixing algorithms for maximizing the number of levels for the given number of IGBTs, drivers and dc sources, and the observations are presented. The efficiency analysis gives the peak efficiency as 98.5%. The simulations were carried out using the PLECS software tool and validated using a prototype rated at 500 W. The results with several test conditions have been reported and discussed in the paper.
Publisher: Hindawi Limited
Date: 26-06-2020
DOI: 10.1002/ER.5631
Publisher: MDPI AG
Date: 02-11-2016
DOI: 10.3390/EN9110899
Publisher: SAGE Publications
Date: 27-07-2017
Abstract: Introduction: Heart failure (HF) accounts for 30% of all global deaths and Asians are likely to suffer from HF 10 years earlier than their Western counterparts. Low self-efficacy and poor health-related quality of life (HRQoL) have been reported in patients with HF. Methodology: A descriptive correlational design was adopted to investigate the associations between self-efficacy and HRQoL in 91 patients with HF in Singapore. Results: Patients with HF demonstrated moderately good self-efficacy ( M = 3.05, SD = 0.61) and HRQoL ( M = 22.48, SD = 18.99). Significant differences were found between total self-efficacy scores and education levels ( p = .05), and between overall HRQoL and smoking status ( p .05). Self-efficacy was not significantly correlated to HRQoL. Smoking status, HF classification, and self-efficacy in maintaining function predicted HRQoL. Discussion: Health care professionals should assess each patient’s demographics, smoking status, and clinical condition before delivering in idualized education to enhance their self-efficacy and, in turn, overall HRQoL.
Publisher: IEEE
Date: 09-2014
Publisher: Springer Science and Business Media LLC
Date: 20-07-2020
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2023
Publisher: Elsevier BV
Date: 11-2016
Publisher: Elsevier BV
Date: 03-2020
Publisher: MDPI AG
Date: 04-01-2013
DOI: 10.3390/EN6010128
Publisher: Elsevier BV
Date: 2017
Publisher: MDPI AG
Date: 27-11-2020
DOI: 10.3390/S20236776
Abstract: Software services communicate with different requisite services over the computer network to accomplish their tasks. The requisite services may not be readily available to test a specific service. Thus, service virtualisation has been proposed as an industry solution to ensure availability of the interactive behaviour of the requisite services. However, the existing techniques of virtualisation cannot satisfy the required accuracy or time constraints to keep up with the competitive business world. These constraints sacrifices quality and testing coverage, thereby delaying the delivery of software. We proposed a novel technique to improve the accuracy of the existing service virtualisation solutions without sacrificing time. This method generates the service response and predicts categorical fields in virtualised responses, extending existing research with lower complexity and higher accuracy. The proposed service virtualisation approach uses conditional entropy to identify the fields that can be used to drive the value of each categorical field based on the historical messages. Then, it uses joint probability distribution to find the best values for the categorical fields. The experimental evaluation illustrates that the proposed approach can generate responses with the required fields and accurate values for categorical fields over four data sets with stateful nature.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2020
Publisher: Springer Science and Business Media LLC
Date: 16-04-2021
Publisher: ACM
Date: 29-10-2018
Publisher: MDPI AG
Date: 16-12-2021
DOI: 10.3390/ELECTRONICS10243132
Abstract: Minimizing the photon losses by depositing an anti-reflection layer can increase the conversion efficiency of the solar cells. In this paper, the impact of anti-reflection coating (ARC) for enhancing the efficiency of silicon solar cells is presented. Initially, the refractive indices and reflectance of various ARC materials were computed numerically using the OPAL2 calculator. After which, the reflectance of SiO2,TiO2,SiNx with different refractive indices (n) were used for analyzing the performance of a silicon solar cells coated with these materials using PC1D simulator. SiNx and TiO2 as single-layer anti-reflection coating (SLARC) yielded a short circuit current density (Jsc) of 38.4 mA/cm2 and 38.09mA/cm2 respectively. Highest efficiency of 20.7% was obtained for the SiNx ARC layer with n=2.15. With Double-layer anti-reflection coating (DLARC), the Jsc improved by ∼0.5 mA/cm2 for SiO2/SiNx layer and hence the efficiency by 0.3%. Blue loss reduces significantly for the DLARC compared with SLARC and hence increase in Jsc by 1 mA/cm2 is observed. The Jsc values obtained is in good agreement with the reflectance values of the ARC layers. The solar cell with DLARC obtained from the study showed that improved conversion efficiency of 21.1% is obtained. Finally, it is essential to understand that the key parameters identified in this simulation study concerning the DLARC fabrication will make experimental validation faster and cheaper.
Publisher: MDPI AG
Date: 18-08-2020
DOI: 10.3390/SU12166687
Abstract: The solar photo-voltaic systems control architecture has a substantial influence over the cost, efficiency, and accuracy of maximum power point tracking under partial shading conditions. In this paper, a novel distributed architecture of a building integrated photo-voltaic system equipped with a single maximum power point tracking controller is presented in order to address the drawbacks associated with respect to cost, complexity and efficiency of the existing photo-voltaic system architectures. In addition, a radial movement optimization based maximum power point tracking control algorithm is designed, developed, and validated using the proposed system architecture under five different partial shading conditions. The inferences obtained from the validation results of the proposed distributed system architecture indicated that cost was reduced by 75% when compared to the commonly used decentralised systems. The proposed distributed building integrated photo-voltaic system architecture is also more efficient, robust, reliable, and accurate.
Publisher: Elsevier BV
Date: 09-2019
Publisher: Springer Science and Business Media LLC
Date: 15-02-2021
Publisher: SPIE
Date: 10-09-2014
DOI: 10.1117/12.2060973
Publisher: Elsevier BV
Date: 2021
DOI: 10.2139/SSRN.3969803
Publisher: IEEE
Date: 24-05-2021
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2019
Publisher: Springer International Publishing
Date: 2022
Publisher: MDPI AG
Date: 14-03-2017
DOI: 10.3390/S17030587
Publisher: Elsevier BV
Date: 12-2013
Publisher: Elsevier
Date: 2021
Publisher: Elsevier BV
Date: 04-2017
Publisher: Elsevier BV
Date: 11-2020
Publisher: IEEE
Date: 05-2019
Publisher: Informa UK Limited
Date: 27-09-2022
DOI: 10.1080/00140139.2021.1977844
Abstract: Tram drivers operate a master controller to control the acceleration and braking of the tram. Operation should ensure passenger comfort and safety through smooth tram motion and the avoidance of jerkiness that may cause passengers to fall in the carriage. This work investigates current driver practices and strategies for tram driving in normal operations through interviews and the capacity of a new haptic master controller to support drivers in achieving smooth and safe tram journeys. A haptic feedback algorithm based on viscosity was implemented on the master controller to provide drivers with feedback on the rate at which they were accelerating and braking the tram. This aspect was tested in a virtual tram within a simulated inner city virtual reality environment. Results indicate that the haptic master controller and coupled viscosity feedback algorithm did not increase smoothness of driving during the simulated experiences. Despite this, the drivers indicated a preference for the provision of further haptic information to support driving tasks and the overall journey safety and smoothness.
Publisher: Elsevier BV
Date: 11-2020
Publisher: IEEE
Date: 02-10-2020
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2021
Publisher: IEEE
Date: 12-2012
Publisher: MDPI AG
Date: 27-08-2021
DOI: 10.3390/EN14175336
Abstract: Electric vehicles’ (EVs) technology is currently emerging as an alternative of traditional Internal Combustion Engine (ICE) vehicles. EVs have been treated as an efficient way for decreasing the production of harmful greenhouse gasses and saving the depleting natural oil reserve. The modern power system tends to be more sustainable with the support of electric vehicles (EVs). However, there have been serious concerns about the network’s safe and reliable operation due to the increasing penetration of EVs into the electric grid. Random or uncoordinated charging activities cause performance degradations and overloading of the network asset. This paper proposes an Optimal Charging Starting Time (OCST)-based coordinated charging algorithm for unplanned EVs’ arrival in a low voltage residential distribution network to minimize the network power losses. A time-of-use (ToU) tariff scheme is used to make the charging course more cost effective. The concept of OCST takes the departure time of EVs into account and schedules the overnight charging event in such a way that minimum network losses are obtained, and EV customers take more advantages of cost-effective tariff zones of ToU scheme. An optimal solution is obtained by employing Binary Evolutionary Programming (BEP). The proposed algorithm is tested on IEEE-31 bus distribution system connected to numerous low voltage residential feeders populated with different EVs’ penetration levels. The results obtained from the coordinated EV charging without OCST are compared with those employing the concept of OCST. The results verify that incorporation of OCST can significantly reduce network power losses, improve system voltage profile and can give more benefits to the EV customers by accommodating them into low-tariff zones.
Publisher: MDPI AG
Date: 10-04-2022
DOI: 10.3390/SU14084495
Abstract: Research into modern transportation systems is currently in progress in order to fully replace the traditional inter-combustible engine with a noiseless, fast, energy-efficient, and environmentally friendly electric vehicle. Electric vehicles depend on an electric motor and require highly efficient converter drive circuits. Among these converters, DC-DC boost converters play a major role in charging not only the battery banks but also in providing the DC-link excitation voltage in transformerless applications. However, the development of these converters, which have higher voltage and current gain with minimum components, minimum voltage, and current stress, is quite challenging. Therefore, this research work aims to address these issues and also to improve overall system performance. These aims are achieved by developing a series LC-based single-stage boost converter, and extending its gain through a multi-stage boost converter using switch capacitor phenomena. This article also presents a complete operating model in continuous conduction mode. The proposed converter is tested under various testing conditions, such as output loading, input voltage levels, and duty cycle ratio for a 50 W resistive load. The results are compared with existing models. The proposed converter is stated to have achieved the highest efficiency, i.e., 96.5%, along with extendable voltage gain with reduced voltage and current stresses, which is a major contribution to this research field.
Publisher: Journal of Modern Power Systems and Clean Energy
Date: 2021
Publisher: Elsevier BV
Date: 07-2017
Publisher: IEEE
Date: 12-2018
Publisher: IEEE
Date: 11-2018
Publisher: Institution of Engineering and Technology
Date: 2019
DOI: 10.1049/CP.2019.1035
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 08-2022
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 05-2021
Publisher: MDPI AG
Date: 13-09-2018
DOI: 10.3390/EN11092431
Abstract: Pakistan is experiencing an undersupply of electricity, causing load shedding several hours per day due to the adherence to conventional energy resources having quantitative and environmental limitations. Fossil fuels generate more than half of the country’s total electricity, but they will ultimately run out due to their limited supply. Their combustion emits greenhouse gases, posing environmental threats. Since the world is tending toward efficient and sustainable alternative methods for harvesting energy from nature, Pakistan has also been investigating an elevated deployment of renewable energy projects. This paper presents a critical analysis of the present energy sector of Pakistan along with global scenarios. Pakistan relies on mainly thermal, hydro, and nuclear energy for power generation. National solar, wind, geothermal, and biomass resources have not been extensively explored and implemented. This paper provides an insight into the potential of these resources in Pakistan to generate electricity for the national grid on a large scale. It focuses on biomass energy, which can be harnessed from bagasse, poultry waste, and municipal waste for power production, and biomass-based fuel for industries and transportation. It concludes that biomass is the most sustainable, available, implementable, and environment-friendly resource that can be utilized to lessen the energy demand and supply gap in Pakistan.
Publisher: IEEE
Date: 09-2015
Publisher: MDPI AG
Date: 09-08-2016
DOI: 10.3390/MA9080672
Publisher: Elsevier BV
Date: 11-2018
Publisher: MDPI AG
Date: 04-02-2018
DOI: 10.3390/EN11020365
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2020
Publisher: WIT Press
Date: 31-03-2015
DOI: 10.2495/ESS140061
Publisher: Springer Science and Business Media LLC
Date: 26-11-2019
Publisher: ACM
Date: 20-06-2018
Publisher: MDPI AG
Date: 02-2021
DOI: 10.3390/APP11031310
Abstract: Modal analysis provides the dynamic behavior of an object or structure, and is often undertaken using the Finite Element Method (FEM) due to its ability to deal with arbitrary geometries. This article investigates the use of Augmented Reality (AR) to provide the in situ visualization of a modal analysis for an aluminum impeller. Finite Element Analysis (FEA) software packages regularly use heat maps and shape deformation to visualize the outcomes of a given simulation. AR allows the superimposition of digital information on a view of the real-world environment, and provides the opportunity to overlay such simulation results onto real-world objects and environments. The presented modal analysis undertaken herein provides natural frequencies and the corresponding deformation of an aluminum impeller. The results indicate the ability for the design part and finite element analysis results to be viewed on the physical part. A mobile AR-FEA-based system was developed for Modal Analysis result visualization. This study offers designers and engineers a new way to visualize such simulation results.
Publisher: Institution of Engineering and Technology (IET)
Date: 09-01-2020
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2015
Publisher: MDPI AG
Date: 17-01-2019
DOI: 10.3390/EN12020286
Abstract: The authors would like to make the following addition to their paper [...]
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 06-2020
Publisher: IEEE
Date: 05-2019
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2023
Publisher: Elsevier BV
Date: 10-2021
Publisher: Elsevier BV
Date: 2017
Publisher: MDPI AG
Date: 26-04-2018
DOI: 10.3390/SU10051347
Publisher: MDPI AG
Date: 15-05-2018
DOI: 10.3390/EN11051260
Publisher: MDPI AG
Date: 08-03-2021
DOI: 10.3390/APP11052381
Abstract: Continuous delivery is an industry software development approach that aims to reduce the delivery time of software and increase the quality assurance within a short development cycle. The fast delivery and improved quality require continuous testing of the developed software service. Testing services are complicated and costly and postponed to the end of development due to unavailability of the requisite services. Therefore, an empirical approach that has been utilised to overcome these challenges is to automate software testing by virtualising the requisite services’ behaviour for the system being tested. Service virtualisation involves analysing the behaviour of software services to uncover their external behaviour in order to generate a light-weight executable model of the requisite services. There are different research areas which can be used to create such a virtual model of services from network interactions or service execution logs, including message format extraction, inferring control model, data model and multi-service dependencies. This paper reviews the state-of-the-art of how these areas have been used in automating the service virtualisation to make available the required environment for testing software. This paper provides a review of the relevant research within these four fields by carrying out a structured study on about 80 research works. These studies were then categorised according to their functional context as, extracting the message format, control model, data model and multi-service dependencies that can be employed to automate the service virtualisation activity. Based on our knowledge, this is the first structural review paper in service virtualisation fields.
Publisher: MDPI AG
Date: 26-01-2021
DOI: 10.3390/SU13031274
Abstract: Few non-traditional optimization techniques are applied to the dynamic economic dispatch (DED) of large-scale thermal power units (TPUs), e.g., 1000 TPUs, that consider the effects of valve-point loading with r -rate limitations. This is a complicated multiple mode problem. In this investigation, a novel optimization technique, namely, a multi-gradient particle swarm optimization (MG-PSO) algorithm with two stages for exploring and exploiting the search space area, is employed as an optimization tool. The M particles (explorers) in the first stage are used to explore new neighborhoods, whereas the M particles (exploiters) in the second stage are used to exploit the best neighborhood. The M particles’ negative gradient variation in both stages causes the equilibrium between the global and local search space capabilities. This algorithm’s authentication is demonstrated on five medium-scale to very large-scale power systems. The MG-PSO algorithm effectively reduces the difficulty of handling the large-scale DED problem, and simulation results confirm this algorithm’s suitability for such a complicated multi-objective problem at varying fitness performance measures and consistency. This algorithm is also applied to estimate the required generation in 24 h to meet load demand changes. This investigation provides useful technical references for economic dispatch operators to update their power system programs in order to achieve economic benefits.
Publisher: Elsevier BV
Date: 10-2021
Publisher: Science Publications
Date: 03-2013
Publisher: MDPI AG
Date: 27-08-2018
DOI: 10.3390/EN11092249
Abstract: This paper presents an in-depth review of classical and state-of-the-art models for analysing the transient stability in wind energy conversion systems. Various transient simulation models for a number of wind turbine generator (WTG) configurations are introduced, under different disturbances. The mitigation is achieved, by manipulating the generator speed and power electronics control, whereas the protection is implemented using conventional, intelligent or digital relays for the safety of sensitive components, in case of transient fault occurrence. The various control systems in WECS are basically employed to transform and regulate the varying frequency, owing to the stochastic nature of wind speed, to the standard 50-Hz or 60-Hz frequency for coupling to an existing electrical utility grid. It has been observed that the control and protection schemes in wind energy systems are concurrently applied. Transient faults in WECSs are a dominant power quality problem especially in the doubly-fed induction generator (DFIG), and often classified as overcurrent or overvoltage transients. These transients are measured using the transient stability index and analysed using the EMTDC/PSCAD software. In addition, the inertia of the rotating masses of wind turbine generators is often characterized by a transient torque, which generates oscillations in power systems.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2022
Publisher: Elsevier BV
Date: 11-2019
Publisher: Elsevier BV
Date: 2021
DOI: 10.2139/SSRN.3932087
Publisher: Wiley
Date: 10-07-2018
Abstract: Due to the so-called energy-gap law and aggregation quenching, the efficiency of organic light-emitting diodes (OLEDs) emitting above 800 nm is significantly lower than that of visible ones. Successful exploitation of triplet emission in phosphorescent materials containing heavy metals has been reported, with OLEDs achieving remarkable external quantum efficiencies (EQEs) up to 3.8% (peak wavelength > 800 nm). For OLEDs incorporating fluorescent materials free from heavy or toxic metals, however, we are not aware of any report of EQEs over 1% (again for emission peaking at wavelengths > 800 nm), even for devices leveraging thermally activated delayed fluorescence (TADF). Here, the development of polymer light-emitting diodes (PLEDs) peaking at 840 nm and exhibiting unprecedented EQEs (in excess of 1.15%) and turn-on voltages as low as 1.7 V is reported. These incorporate a novel triazolobenzothiadiazole-based emitter and a novel indacenodithiophene-based transport polymer matrix, affording excellent spectral and transport properties. To the best of knowledge, such values are the best ever reported for electroluminescence at 840 nm with a purely organic and solution-processed active layer, not leveraging triplet-assisted emission.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 12-2019
Publisher: MDPI AG
Date: 13-08-2021
DOI: 10.3390/EN14164986
Abstract: Expeditious urbanization and rapid industrialization have significantly influenced the rise of energy demand globally in the past two decades. Solar energy is considered a vital energy source that addresses this demand in a cost-effective and environmentally friendly manner. Improving solar cell efficiency is considered a prerequisite to reinforcing silicon solar cells’ growth in the energy market. In this study, the influence of various parameters like the thickness of the absorber or wafer, doping concentration, bulk resistivity, lifetime, and doping levels of the emitter and back surface field, along with the surface recombination velocity (front and back) on solar cell efficiency was investigated using PC1D simulation software. Inferences from the results indicated that the bulk resistivity of 1 Ω·cm bulk lifetime of 2 ms emitter (n+) doping concentration of 1×1020 cm−3 and shallow back surface field doping concentration of 1×1018 cm−3 surface recombination velocity maintained in the range of 102 and 103 cm/s obtained a solar cell efficiency of 19%. The Simulation study presented in this article allows faster, simpler, and easier impact analysis of the design considerations on the Si solar cell wafer fabrications with increased performance.
Publisher: Elsevier BV
Date: 11-2020
Publisher: Wiley
Date: 05-09-2016
Publisher: IEEE
Date: 09-2014
Publisher: MDPI AG
Date: 03-10-2020
DOI: 10.3390/S20195664
Abstract: Continuous delivery has gained increased popularity in industry as a development approach to develop, test, and deploy enhancements to software components in short development cycles. In order for continuous delivery to be effectively adopted, the services that a component depends upon must be readily available to software engineers in order to systematically apply quality assurance techniques. However, this may not always be possible as (i) these requisite services may have limited access and (ii) defects that are introduced in a component under development may cause ripple effects in real deployment environments. Service virtualisation (SV) has been introduced as an approach to address these challenges, but existing approaches to SV still fall short of delivering the required accuracy and/or ease-of-use to virtualise services for adoption in continuous delivery. In this work, we propose a novel machine learning based approach to predict numeric fields in virtualised responses, extending existing research that has provided a way to produce values for categorical fields. The SV approach introduced here uses machine learning techniques to derive values of numeric fields that are based on a variable number of pertinent historic messages. Our empirical evaluation demonstrates that the Cognitive SV approach can produce responses with the appropriate fields and accurately predict values of numeric fields across three data sets, some of them based on stateful protocols.
Publisher: Elsevier BV
Date: 03-2020
Publisher: Springer Science and Business Media LLC
Date: 10-12-2014
Publisher: Institution of Engineering and Technology (IET)
Date: 20-04-2021
DOI: 10.1049/PEL2.12113
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 10-2018
Publisher: Elsevier BV
Date: 09-2021
Publisher: MDPI AG
Date: 11-2017
DOI: 10.3390/SU9112006
Publisher: MDPI AG
Date: 13-05-2019
DOI: 10.3390/EN12091810
Abstract: Multilevel inverters are proficient in achieving a high-quality staircase output voltage waveform with a lower amount of harmonic content. In this paper, a new hybrid multilevel inverter topology based on the T-type and H-bridge module is presented. The proposed topology aims to achieve a higher number of levels utilizing a lower number of switches, direct current (dc) voltage sources, and voltage stresses across different switches. The basic unit of the proposed single T-type and double H-bridge multilevel inverter (STDH-MLI) produces 15 levels at the output using three dc voltage sources. The proposed topology can be extended by connecting a larger number of dc voltage sources in the T-type section. The nearest level control (NLC) switching technique is used to generate gate pulses for switches to achieve a high-quality output voltage waveform. In addition, a simplified way to achieve NLC is also described in the paper. A detailed comparison with other similar topologies is provided to set the benchmark of the proposed topology. Finally, experimental work is carried out to validate the performance of the proposed topology.
Publisher: MDPI AG
Date: 03-03-2021
DOI: 10.3390/APP11052229
Abstract: In this paper, a novel deep neural network-based energy prediction algorithm for accurately forecasting the day-ahead hourly energy consumption profile of a residential building considering occupancy rate is proposed. Accurate estimation of residential load profiles helps energy providers and utility companies develop an optimal generation schedule to address the demand. Initially, a comprehensive multi-criteria analysis of different machine learning approaches used in energy consumption predictions was carried out. Later, a predictive micro-grid model was formulated to synthetically generate the stochastic load profiles considering occupancy rate as the critical input. Finally, the synthetically generated data were used to train the proposed eight-layer deep neural network-based model and evaluated using root mean square error and coefficient of determination as metrics. Observations from the results indicated that the proposed energy prediction algorithm yielded a coefficient of determination of 97.5% and a significantly low root mean square error of 111 Watts, thereby outperforming the other baseline approaches, such as extreme gradient boost, multiple linear regression, and simple/shallow artificial neural network.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2023
Publisher: Elsevier BV
Date: 08-2018
DOI: 10.1016/J.NEDT.2018.04.020
Abstract: The shortage of nurses has become a global phenomenon, and methods of decreasing the attrition rate of nurses have been explored. Resilience was one of the important factors that increased the retention rate of nurses who stayed in this highly stressful profession. To understand how undergraduate nursing students perceive and experience their clinical placements and to identify the factors that helped them build resilience. A qualitative design utilizing focus group interviews was adopted for this study. Nineteen third- and fourth-year undergraduate nursing students in a Bachelor of Nursing program participated in this study. This study was conducted at a local university in Singapore. Four audio-taped focus group interviews were conducted. Students reported that they were stressed while facing challenges head-on during their first clinical placements, mainly due to a lack of peer and clinical support. Gradually, students built resilience overtime and were able to adapt to the ward culture through peer support and reframing coping strategies. Nursing students gradually built resilience after accumulating experiences from their clinical placements. Although they eventually adapted well, peer, clinical, and informational support during clinical placements were lacking. Resilience programs that teach positive coping strategies and mindfulness training could be implemented in the undergraduate nursing curriculum.
Publisher: Elsevier BV
Date: 10-2019
Publisher: MDPI AG
Date: 20-05-2021
DOI: 10.3390/SU13105731
Abstract: Physical activity is connected to public health in many ways, and walking is its most popular form. Modern planning models have been applied to cities to manage rapid urban expansions. However, this practice has led to low level of walkability and strong car-dependency in today’s cities. Hence, this study aims to provide a review of the most promising urban design parameters affecting walkability, using Frank Lawrence’s theory of “Objectively Measured Urban Form” (density, connectivity and accessibility, and mixed-use development) as the basis of discussion. The second part of this paper takes a case study approach, through discussing the main design elements of traditional Iranian cities (mosques, bazaars, residential quarters, and alleyways) and analyses their impacts on promoting walkability. This study concludes that incorporating inherent values of traditional urban design elements will complement modern planning and design practices.
Publisher: American Chemical Society (ACS)
Date: 11-07-2013
DOI: 10.1021/NN402022Z
Abstract: The structural nature of heterointerfaces in core-shell semiconductor quantum dots (QDs) plays a crucial role in tailoring their optical properties. In this work we have focused on using surface-enhanced Raman spectroscopy as a nondestructive tool to investigate the structural evolution of such interfaces in CdSe/CdS and CdSe/Cd0.5Zn0.5S colloidal QDs. A comparison between the two systems shows significant structural variation across the core-shell interfaces for the two different materials: a smooth interface for the former and an abrupt interface for the latter. This structural difference modifies the electronic structure within the QDs, which directly dictates the confinement behavior of the electrons and holes. The implications of this translate to a better understanding of why graded CdSe/CdS/Cd0.5Zn0.5S/ZnS QDs are so lucrative for linear and nonlinear fluorescence-based applications.
Publisher: MDPI AG
Date: 11-02-2022
Abstract: Increasing silicon solar cell efficiency plays a vital role in improving the dominant market share of photo-voltaic systems in the renewable energy sector. The performance of the solar cells can be evaluated by making a profound analysis on various effective parameters, such as the sheet resistance, doping concentration, thickness of the solar cell, arbitrary dopant profile, etc., using software simulation tools, such as PC1D. In this paper, we present the observations obtained from the evaluation carried out on the impact of sheet resistance on the solar cell’s parameters using PC1D software. After which, the EDNA2 simulation tool was used to analyse the emitter saturation current density for the chosen arbitrary dopant profile. Results indicated that the diffusion profile with low surface concentration and shallow junction depth can improve the blue response at the frontal side of the solar cell. The emitter saturation current density decreases from 66.52 to 36.82 fA/cm2 for the subsequent increase in sheet resistance. The blue response also increased from 89.6% to 97.5% with rise in sheet resistance. In addition, the short circuit density and open circuit voltage was also observed to be improved by 0.6 mA/cm2 and 3 mV for the sheet resistance value of 130 Ω/sq, which resulted in achieving the highest efficiency of 20.6%.
Publisher: AIP Publishing
Date: 03-2014
DOI: 10.1063/1.4868025
Abstract: Partial shading is one of the unavoidable complications in the field of solar power generation. Although the most common approach in increasing a photovoltaic (PV) array's efficiency has always been to introduce a bypass diode to the said array, this poses another problem in the form of multi-peaks curves whenever the modules are partially shaded. To further complicate matters, most conventional Maximum Power Point Tracking methods develop errors under certain circumstances (for ex le, they detect the local Maximum Power Point (MPP) instead of the global MPP) and reduce the efficiency of PV systems even further. Presently, much research has been undertaken to improve upon them. This study aims to employ an evolutionary algorithm technique, also known as particle swarm optimization, in MPP detection.
Publisher: IEEE
Date: 09-2018
Publisher: American Chemical Society (ACS)
Date: 10-2014
DOI: 10.1021/JP506778N
Publisher: Elsevier BV
Date: 12-2020
Publisher: Frontiers Media SA
Date: 22-07-2021
DOI: 10.3389/FENRG.2021.671973
Abstract: Growing populations, burgeoning economies, and technology-driven lifestyles demand an increasing supply of energy. The existing energy supply pattern primarily depends on fossil fuels that have initiated climate change–provoking myriad problems. Integration of renewable energy sources in the existing energy supply system is a complex and challenging task keeping in view the depleting fossil fuels and prevailing environmental challenges. The existing cold storage farms are working on traditional compressors and the HVAC system, causing more use of electricity. Similarly, existing data centers and supermarkets are also using conventional refrigerants. These systems also use hazardous environmental refrigerants, which make these systems more dangerous. In the summer season, comfort cooling and refrigeration requirements rise to peak in hot climate areas forcing utilities to supply more electrical energy to meet the demand. Therefore, a solar thermal cooling system employing a solar absorption chiller operated through a hot water stream generated by a solar evacuated glass tube collector with CO 2 as a refrigerant is simulated in the TRNSYS® simulation environment. The results are generated for the hot climate of Multan, Pakistan, and the average obtained temperatures of the three rooms, cold storage, office, and kitchen room, were 18.43, 26.25, and 29.83°C, respectively. However, every startup or new idea needs a proper business model before entering into the market. This article offers a complete insight and a future perspective for the reader to develop a precise business model for the commercialization of his or her project. A business model is designed for solar thermal air conditioners for domestic, cold storage, and data centers applications in the world, after reviewing and interviewing manufacturers and customer segment in air conditioning fields. Data were collected through semi-structured one-to-one interviews from a convenient s le of 10 national and international respondents, and their views were thematically analyzed. The implementation of a business model using a case for the Pakistani market is presented. A business model for a solar cooling system utilizing abundant CO 2 as a refrigerant is presented in this article. This business model is equally suitable for designing a business model for any renewable energy product in the world.
Publisher: IEEE
Date: 11-2017
Publisher: Zenodo
Date: 2015
Publisher: BMJ
Date: 03-04-2023
Abstract: To assess intraocular pressure (IOP)-induced and gaze-induced optic nerve head (ONH) strains in subjects with high-tension glaucoma (HTG) and normal-tension glaucoma (NTG). Clinic-based cross-sectional study. The ONH from one eye of 228 subjects (114 subjects with HTG (pre-treatment IOP≥21 mm Hg) and 114 with NTG (pre-treatment IOP mm Hg)) was imaged with optical coherence tomography (OCT) under the following conditions: (1) OCT primary gaze, (2) 20° adduction from OCT primary gaze, (3) 20° abduction from OCT primary gaze and (4) OCT primary gaze with acute IOP elevation (to approximately 33 mm Hg). We then performed digital volume correlation analysis to quantify IOP-induced and gaze-induced ONH tissue deformations and strains. Across all subjects, adduction generated high effective strain (4.4%±2.3%) in the LC tissue with no significant difference (p .05) with those induced by IOP elevation (4.5%±2.4%) while abduction generated significantly lower (p=0.01) effective strain (3.1%±1.9%). The lamina cribrosa (LC) of HTG subjects exhibited significantly higher effective strain than those of NTG subjects under IOP elevation (HTG: 4.6%±1.7% vs NTG: 4.1%±1.5%, p .05). Conversely, the LC of NTG subjects exhibited significantly higher effective strain than those of HTG subjects under adduction (NTG: 4.9%±1.9% vs HTG: 4.0%±1.4%, p .05). We found that NTG subjects experienced higher strains due to adduction than HTG subjects, while HTG subjects experienced higher strain due to IOP elevation than NTG subjects—and that these differences were most pronounced in the LC tissue.
Publisher: Public Library of Science (PLoS)
Date: 27-04-2018
Publisher: IEEE
Date: 07-2018
Publisher: Elsevier BV
Date: 11-2019
DOI: 10.1016/J.SCITOTENV.2019.06.399
Abstract: Urban climate knowledge has been increasingly integrated into urban design and planning practices. Numerical modeling systems, such as climatic and bioclimatic tools, are currently more popular than onsite field measurements. This higher popularity is mainly due to the complicated interactions in 3D urban environments and the spatial distribution of various climatic parameters that cannot be captured thoroughly via on-site measurements alone. Such modeling systems also offer better solutions to overcome the nonlinearity of urban climate in forecasting different "what if scenarios." This paper provides an overview of different types of climatic and bioclimatic modeling systems and presents their main benefits and shortcomings. In the second part of this study, one of the most commonly used tools in urban climate studies, namely, ENVI-met, was selected, and its reliability in different contexts was investigated by reviewing past researches. The applicability of ENVI-met in accurately simulating the influence of future urban growth on one of the fastest growing suburbs in Melbourne, was tested by conducting a sensitivity analysis on inputs and control parameters, backed up with a series of field measurements in selected points. RMSE value was calculated for different runs of the initial ENVI-met model with adjusted control parameters (e.g., factor of short-wave adjustment, initial air temperature, relative humidity, roughness length, wind speed, albedo of walls, and albedo of roofs). The model achieved the optimum performance by altering the short-wave adjustment factor from 0.5 to 1 therefore, ENVI-met was considered a reliable tool for relative comparison of urban dynamics. The findings of this study not only help planners select the most practical modeling systems that address project objectives but also educate them on limitations associated with using ENVI-met.
Publisher: MDPI AG
Date: 29-06-2017
DOI: 10.3390/EN10070876
Publisher: MDPI AG
Date: 29-06-2021
DOI: 10.3390/SU13137253
Abstract: In view of the problem of e-commerce scams and the absence of haptic interaction, this research aims to introduce and create a tele-weight device for e-commerce shopping in smart cities. The objective is to use the proposed prototype to provide a brief overview of the possible technological advancements. When the tele-weight device is affixed over the head-mounted display, it allows the user to feel the item’s weight while shopping in the virtual store. Addressing the problem of having no physical interaction between the user (player) and a series game scene in virtual reality (VR) headsets, this research approach focuses on creating a prototype device that has two parts, a sending part and a receiving part. The sending part measures the weight of the object and transmits it over the cellular network to the receiver side. The virtual store user at the receiving side can thus realize the weight of the ordered object. The findings from this work include a visual display of the item’s weight to the virtual store e-commerce user. By introducing sustainability, this haptic technology-assisted technique can help the customer realize the weight of an object and thus have a better immersive experience. In the device, the load cell measures the weight of the object and lifies it using the HX711 lifier. However, some delay in the demonstration of the weight was observed during experimentation, and this indirectly altered the performance of the system. One set of the device is sited at the virtual store user premises while the sending end of the device is positioned at the warehouse. The sending end hardware includes an Arduino Uno device, an HX711 lifier chip to lify the weight from the load cell, and a cellular module (Sim900A chip-based) to transmit the weight in the form of an encoded message. The receiving end hardware includes a cellular module and an actuator involving a motor gear arrangement to demonstrate the weight of the object. Combining the fields of e-commerce, embedded systems, VR, and haptic sensing, this research can help create a more secure marketplace to attain a higher level of customer satisfaction.
Publisher: Elsevier BV
Date: 02-0011
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2020
Publisher: Elsevier BV
Date: 02-2016
Publisher: Elsevier BV
Date: 04-2018
Publisher: Elsevier BV
Date: 2018
Publisher: Institution of Engineering and Technology (IET)
Date: 11-2020
Publisher: International Academy Publishing (IAP)
Date: 2014
No related grants have been discovered for Mohammadmehdi Seyedmahmoudian.