ORCID Profile
0000-0002-2197-3325
Current Organisations
Institut Català d' Oncologia
,
UNSW Sydney
,
Hospital Clínic de Barcelona
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Publisher: IEEE
Date: 09-2011
Publisher: MDPI AG
Date: 27-11-2022
DOI: 10.3390/ACT11120349
Abstract: Electric machines are highly efficient and highly controllable actuators, but they do still suffer from a number of imperfections. One of them is torque ripple, which introduces high frequency harmonics into the motion. One (cost- and performance-neutral) countermeasure is to apply control that counters the torque ripple. This paper compares several single-input single-output (SISO) control approaches for feedback control of torque ripple of a Permanent Magnet Synchronous Machine (PMSM). The baseline is PI (proportional-integral) control, which does not suppress torque ripple, and the most popular control approach is proportional-integral resonant (PIR) control. Both are compared to an advanced PIR controller (PIRA), frequency modulation, a mixed sensitivity design, and an iterative learning controller (ILC). The analysis demonstrates that PIR control, mixed sensitivity state feedback, and the modulating controller achieve identical behaviour. The choice between these three options is therefore dependent on preferences for the design methodology, or on implementation factors. The PIRA and the ILC on the other hand show more sophisticated behaviour that may be advantageous for certain applications, at the expense of higher complexity.
Publisher: SAGE Publications
Date: 06-02-2023
DOI: 10.1177/09544097231154378
Abstract: A fault-tolerant control scheme (FTCS) was developed for a novel mechatronic track switch for the first time. The FTCS was first developed and tested on a simulation model of the system, before being applied to an experimental actuation system in the laboratory. Both the simulation and experimental results show that this FTCS works as expected and allows the switch to continue operating as desired under sensor failure, preventing damage to the switch.
Publisher: American Chemical Society (ACS)
Date: 27-01-2016
Abstract: Dual fuel diesel and natural gas heavy goods vehicles (HGVs) operate on a combination of the two fuels simultaneously. By substituting diesel for natural gas, vehicle operators can benefit from reduced fuel costs and as natural gas has a lower CO2 intensity compared to diesel, dual fuel HGVs have the potential to reduce greenhouse gas (GHG) emissions from the freight sector. In this study, energy consumption, greenhouse gas and noxious emissions for five after-market dual fuel configurations of two vehicle platforms are compared relative to their diesel-only baseline values over transient and steady state testing. Over a transient cycle, CO2 emissions are reduced by up to 9% however, methane (CH4) emissions due to incomplete combustion lead to CO2e emissions that are 50-127% higher than the equivalent diesel vehicle. Oxidation catalysts evaluated on the vehicles at steady state reduced CH4 emissions by at most 15% at exhaust gas temperatures representative of transient conditions. This study highlights that control of CH4 emissions and improved control of in-cylinder CH4 combustion are required to reduce total GHG emissions of dual fuel HGVs relative to diesel vehicles.
Publisher: SAGE Publications
Date: 03-07-2022
DOI: 10.1177/09544070211026196
Abstract: The development, modelling and testing of a novel, fuel-efficient hydraulic hybrid light truck is reported. The vehicle used a Digital Displacement ® pump/motor and a foam-filled hydraulic accumulator in parallel with the existing drivetrain to recover energy from vehicle braking and use this during acceleration. The pump/motor was also used to reduce gear-shift times. The paper describes the development of a mathematical vehicle model and the validation of this model against an extensive testing regime. In testing, the system improved the fuel economy of the vehicle by 23.5% over the JE05 midtown drive cycle. The validated mathematical model was then optimised and used to determine the maximum fuel economy improvement over the diesel baseline vehicle for two representative cycles (JE05 midtown and WLTP). It was found that the hybrid system can improve the fuel economy by 24%–43%, depending on the drive cycle. When this was combined with engine stop-start, the system improved the fuel economy of the vehicle by 29%–95%, depending on the drive cycle.
Publisher: Public Library of Science (PLoS)
Date: 07-11-2012
Publisher: SAGE Publications
Date: 06-08-2016
Abstract: This paper investigates the fuel consumption of an articulated vehicle with a hydraulic regenerative braking system. The vehicle is a four-axle tractor–semitrailer with a volume-limited payload. It is equipped with hub-mounted hydraulic pump–motor units that pump fluid from a low-pressure reservoir to a high-pressure reservoir during braking events and generate a propulsive torque when high-pressure fluid flows through them to the low-pressure reservoir during acceleration. Several possible control strategies are proposed and simulated using a validated mathematical model of the fuel consumption of the vehicle. A global optimisation calculation indicates that the maximum possible reduction in fuel consumption due to the regenerative braking system is 11–22%, depending on the driving cycle. The simulations indicate that the simple ‘greedy’ algorithm decreases the fuel consumption by 9–17% for the same conditions. Two heuristic algorithms and a model predictive control approach were also investigated. Although these more sophisticated controllers were able to improve on the greedy controller slightly for some conditions, they may not be implementable in practice.
Publisher: Elsevier BV
Date: 02-2019
Publisher: Elsevier BV
Date: 02-2019
Publisher: Wiley
Date: 02-2007
DOI: 10.1002/GCC.20396
Abstract: A large number of nevi (LNN) is a high risk phenotypic trait for developing cutaneous malignant melanoma (CMM). In this study, the breakpoints of a t(9 )(p21 q13) balanced chromosome translocation were finely mapped in a family with LNN and CMM. Molecular characterization of the 9p21 breakpoint identified a novel gene C9orf14 expressed in melanocytes disrupted by the translocation. Integrative analysis of functional genomics data was applied to determine the role of C9orf14 in CMM development. An analysis of genome-wide DNA copy number alterations in melanoma tumors revealed the loss of the C9orf14 locus, located proximal to CDKN2A, in approximately one-fourth of tumors. Analysis of gene expression data in cancer cell lines and melanoma tumors suggests a loss of C9orf14 expression in melanoma tumorigenesis. Taken together, our results indicate that C9orf14 is a candidate tumor-suppressor for nevus development and late stage melanoma at 9p21, a region frequently deleted in different types of human cancers.
Publisher: Wiley
Date: 13-08-2021
DOI: 10.1002/SYS.21597
Abstract: The systems‐engineering context of the solid waste disposal problem is discussed with a focus on the issues in Saudi Arabia. A methodology was developed for iding the system of interest into a set of weakly‐coupled sub‐systems that interact with the narrow system of interest. A model of the narrow system of interest, in this case the municipal solid waste (MSW) system of Saudi Arabia, was then created and validated. The development of this mathematical model is described and is used to investigate a range of scenarios for the future of Saudi Arabia's MSW system with a time horizon of 30 years. The most effective method uses anaerobic digestion, incineration and recycling to reduce the total mass to landfill over the 30 years by 73% when compared to the default scenario (no action taken). In the final year of the simulation, this method reduces the total annual mass to landfill by 69% when compared to a reasonable source reduction strategy. The energy generated by incineration, is shown to contribute a maximum of 2.3% to the Kingdom's annual energy production. Lifecycle analysis shows that the best waste management method produces a DALY (disability life year) score which is 2% of the current strategy, even if moderate source reduction is employed. The two newly suggested scenarios are shown to have a net positive impact on the environment due to the recycling of a large part of the waste stream, preventing acidification/eutrophication due to the manufacture of virgin goods.
Publisher: SAGE Publications
Date: 12-03-2015
Abstract: This paper investigates the traffic-related effects of a proposal to increase the speed limit from 40 mile/h to 50 mile/h, for heavy goods vehicles greater than 7.5 tonnes, on single carriageway roads. A ‘microscopic’ single carriageway traffic simulation is developed by combining the ‘enhanced intelligent driver model’ with a single carriageway gap-acceptance passing model. Fuel consumption estimates are made using engine characteristic maps and a ‘fuel optimal’ gear selection scheme, where vehicle trajectories from the traffic simulations are taken as input drive-cycles. Traffic congestion and fleet fuel consumption are specifically addressed, though implications regarding passing behaviour and traffic safety are also noted. Results indicate that the proposed 50 mile/h heavy goods vehicles speed limit would reduce traffic congestion by over 37% and increase fleet fuel consumption by approximately 0.5 L/100 km.
Publisher: SAGE Publications
Date: 15-01-2013
Abstract: A hydraulic regenerative braking system for an articulated heavy vehicle is modelled for an idealised urban driving cycle, consisting of one stop and start from 30 mile/h, in a distance of 700 m. This model is used to guide specification of a hardware system but not to investigate brake blending methods or the torque distribution during braking. The specified system consists of a high-pressure accumulator and a low-pressure accumulator, connected by two fixed-displacement in-wheel pump–motors. One of these systems is fitted to each of the three trailer axles. This system can produce a fuel consumption saving of 21.7% over an idealised stop–start cycle. The same system was simulated over the Heavy Heavy-Duty Diesel Truck transient mode, New York City and Urban Driving Dynamometer Schedule legislative driving cycles, reducing fuel consumption by 11.2%, 17% and 11.7% respectively. Fuel consumption can be further reduced for all these cycles if engine stop–start technology is used. The potential to use the system when traversing hilly terrain was investigated, and the system was found to reduce fuel consumption by 12.6% over a V-shaped valley and by up to 5.3% over a realistic elevation profile.
Publisher: SAGE Publications
Date: 15-02-2021
Abstract: The development, validation and control of a bi-mode train model is presented. A detailed modular model of a United Kingdom Class 800 train, which included carbon dioxide emissions data, was developed in MATLAB/Simulink. This model was validated against data obtained from a full day of rail journeys in the south-west of England. The validated model was used to develop control measures to reduce the carbon dioxide emissions of the train. Combining adaptive speed limit control with selective engine shutdown reduced the carbon dioxide emissions by 19.1% over a representative route without affecting the train’s on-time performance. The model was used to develop a tool for investigating the emissions benefits of (intermittent/discontinuous) route electrification. This tool shows that electrification of a route can reduce the carbon dioxide emissions by 66%.
Publisher: Springer Science and Business Media LLC
Date: 27-07-2021
DOI: 10.1007/S40534-021-00248-9
Abstract: A near-term strategy to reduce emissions from rail vehicles, as a path to full electrification for maximal decarbonisation, is to partially electrify a route, with the remainder of the route requiring an additional self-powered traction option. These rail vehicles are usually powered by a diesel engine when not operating on electrified track and are referred to as bi-mode vehicles. This paper analyses the benefits of discontinuous electrification compared to continuous electrification using the CO 2 estimates from a validated high-fidelity bi-mode (diesel-electric) rail vehicle model. This analysis shows that 50% discontinuous electrification provides a maximum of 54% reduction in operational CO 2 emissions when compared to the same length of continuously electrified track. The highest emissions savings occurred when leaving train stations where vehicles must accelerate quickly to line speed. These results were used to develop a linear regression model for fast estimation of CO 2 emissions from diesel running and electrification benefits. This model was able to estimate the CO 2 emissions from a route to within 10% of that given by the high-fidelity model. Finally, additional considerations such as cost and the embodied CO 2 in electrification infrastructure were analysed to provide a comparison between continuous and discontinuous electrification. Discontinuous electrification can cost up to 56% less per reduction in lifetime emissions than continuous electrification and can save up to 2.3 times more lifetime CO 2 per distance electrified.
Publisher: SAGE Publications
Date: 02-2017
Abstract: A novel fuel-efficient articulated urban delivery vehicle is developed and tested. The vehicle has a path-following steering system on the semitrailer which improves its manoeuvrability in narrow city streets. This enables the payload to be increased from 39.4 m 3 of freight on a conventional rigid delivery vehicle to 84.2 m 3 on this articulated counterpart, leading directly to up to 33% fuel saving per unit of freight task. The vehicle is also equipped with a hydraulic regenerative braking system which stores energy in hydraulic accumulators during braking events and releases this energy back to accelerate the vehicle in subsequent motion. The design of this system and the field testing programme are described. The experimental tests are used to determine the hydraulic losses and to validate a mathematical model of the vehicle and the regenerative braking system. Finally, the validated mathematical model is used to perform a parametric study for the vehicle operating in various standard driving cycles. It is found that operating the regenerative braking system with an engine stop–start system and optimized accumulator precharge pressures can reduce the fuel consumption by 9–18% in comparison with that of the baseline vehicle, depending on the driving cycle. When combined with the performance improvements due to the trailer steering system and additional payload, this gives an overall reduction in the fuel consumption of 35–42%.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2023
Publisher: SAGE Publications
Date: 14-03-2012
Abstract: One way to reduce the carbon dioxide emissions of heavy vehicles is to install regenerative braking systems. These capture the kinetic energy of the vehicle during braking and store it, in order to feed it back into the drivetrain during acceleration. It is not clear, however, which of the many available technologies should be used to implement this regenerative braking. This report explores the different possible energy capture and storage technologies for regenerative braking, including electrical, kinetic, hydraulic and compressed air. The basic systems are plotted on a selection chart, and an optimal selection methodology is used to aid in the selection of the lightest and smallest system for regenerative braking. The results of this comparison and selection show that hydraulic energy storage is likely to be 33% smaller and 20% lighter than the closest electrical counterparts and is therefore a logical selection for regenerative braking on the trailers of heavy goods vehicles.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 03-2023
Publisher: SAGE Publications
Date: 28-02-2023
DOI: 10.1177/09544097231159179
Abstract: The fastest way to decarbonise traction energy of a railway network is full electrification of the network. However, full electrification can be costly and is often delayed due to complicated planning procedures. Often, it is not financially viable to electrify certain sections of the network due to geographical challenges such as hillsides and requirements to raise or lower the tracks. Intermittent electrification can provide a way to reduce emissions on a route without fully electrifying it. This paper presents an optimal intermittent electrification strategy and compares its effects on required battery size to a ‘common-sense’ approach. The “common-sense” approach is a heuristic electrification method where high-power sections of the route are electrified first. Energy savings are demonstrated using a validated high-fidelity bi-mode train model on the Newbury-Plymouth route of Great Western Railway in the UK. Unlike prior research, the optimal electrification strategy considers energy consumptions for both directions of a journey on the route and is therefore optimal regardless of travel direction. The 278-km Newbury-Plymouth route was ided into 50 equal discrete sections for the optimization process, which then identified sections that should be prioritised for electrification as they consume the maximum energy. A high charge/discharge lithium titanite-oxide battery was modelled and installed on the virtual vehicle to determine the required battery sizing for given optimal percentages of intermittent electrification. The battery sizing strategy includes battery wear effects from charge/discharge cycle life and shows the battery life to be 1.42 years if kept at 55°C and 6 years if kept at 25°C. At 36% electrification, using the ‘common-sense’ approach, the battery weighs 10,500 kg and the battery-OLE train reduces the CO 2 emissions and energy usage on the route by 83% when compared to the diesel-only train.
Publisher: Oxford University Press (OUP)
Date: 12-2004
DOI: 10.1093/HMG/DDI028
Abstract: Cancer cells are characterized by a generalized disruption of the DNA methylation pattern involving an overall decrease in the level of 5-methylcytosine together with regional hypermethylation of particular CpG islands. The extent of both DNA hypomethylation and hypermethylation in the tumor cell is likely to reflect distinctive biological and clinical features, although no studies have addressed its concurrent analysis until now. DNA methylation profiles in sporadic colorectal carcinomas, synchronous adenoma-carcinoma pairs and their matching normal mucosa were analyzed by using the lification of inter-methylated sites (AIMS) method. A total of 208 AIMS generated sequences were tagged and evaluated for differential methylation. Global indices of hypermethylation and hypomethylation were calculated. All tumors displayed altered patterns of DNA methylation in reference to normal tissue. On average, 24% of the tagged sequences were differentially methylated in the tumor in regard to the normal pair with an overall prevalence of hypomethylations to hypermethylations. Carcinomas exhibited higher levels of hypermethylation than did adenomas but similar levels of hypomethylation. Indices of hypomethylation and hypermethylation showed independent correlations with patient's sex, tumor staging and specific gene hypermethylation. Hierarchical cluster analysis revealed two main patterns of DNA methylation that were associated to particular mutational spectra in the K-ras and the p53 genes and alternative correlates of hypomethylation and hypermethylation with survival. We conclude that DNA hypermethylation and hypomethylation are independent processes and appear to play different roles in colorectal tumor progression. Subgroups of colorectal tumors show specific genetic and epigenetic signatures and display distinctive correlates with overall survival.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United States of America
Start Date: 2021
End Date: 2021
Funder: Engineering and Physical Sciences Research Council
View Funded ActivityStart Date: 2020
End Date: 2022
Funder: Engineering and Physical Sciences Research Council
View Funded Activity