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Imaging atomic-scale chemistry from fused multi-modal electron microscopy

npj Computational Materials 2022年第1期8卷 164-171页

作者： Jonathan Schwartz Zichao Wendy di Yi Jiang Alyssa J.Fielitz don-Hyung Ha Sanjaya D.Perera Ismail El Baggari Richard d.Robinson Jeffrey A.Fessler Colin Ophus Steve Rozeveld Robert Hovden department of Materials Science and Engineering University of MichiganAnn ArborMIUSA Mathematics and Computer Science division Argonne National LaboratoryLemontILUSA Advanced Photon Source Facility Argonne National LaboratoryLemontILUSA dow Chemical Co. MidlandMIUSA department of Material Science and Engineering Cornell UniversityIthacaNew YorkUSA School of Integrative Engineering Chung-Ang UniversitySeoulRepublic of Korea department of Physics Cornell UniversityIthacaNYUSA The Rowland Institute at Harvard CambridgeMAUSA department of Electrical Engineering and Computer Science University of MichiganAnn ArborMIUSA National Center for Electron Microscopy Lawrence Berkeley National LaboratoryMolecular FoundryBerkeleyCAUSA Applied Physics Program University of MIchiganAnn ArborMIUnited States

Efforts to map atomic-scale chemistry at low doses with minimal noise using electron microscopes are fundamentally limited by inelastic interactions.Here,fused multi-modal electron microscopy offers high signal-to-noise ratio(SNR)recovery of material chemistry at nano-and atomic-resolution by coupling correlated information encoded within both elastic scattering(high-angle annular dark-field(HAAdF))and inelastic spectroscopic signals(electron energy loss(EELS)or energy-dispersive x-ray(EdX)).By linking these simultaneously acquired signals,or modalities,the chemical distribution within nanomaterials can be imaged at significantly lower doses with existing detector hardware.In many cases,the dose requirements can be reduced by over one order of magnitude.This high SNR recovery of chemistry is tested against simulated and experimental atomic resolution data of heterogeneous nanomaterials.

关键词： materials chemistry fused

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Towards climate resilient urban energy systems: a review

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National Science Review 2021年第3期8卷 159-176页

作者： Vahid M.Nik A.T.d.perera deliang Chen division of Building Physics Department of Building and Environmental Technology Lund University Institute for Future Environments(IFE) Queensland University of Technology(QUT) Regional Climate Group Department of Earth SciencesUniversity of Gothenburg division of Building Technology Department of Architecture and Civil Engineering Chalmers University of Technology Solar Energy and Building Physics Laboratory(LESO-PB) Ecole Polytechnique Federale de Lausanne(EPFL) Urban Energy Systems Laboratory

Climate change and increased urban population are two major concerns for society.Moving towards more sustainable energy solutions in the urban context by integrating renewable energy technologies supports decarbonizing the energy sector and climate change mitigation.A successful transition also needs adequate consideration of climate change including extreme events to ensure the reliable performance of energy systems in the long run.This review provides an overview of and insight into the progress achieved in the energy sector to adapt to climate change,focusing on the climate resilience of urban energy systems.The state-of-the-art methodology to assess impacts of climate change including extreme events and uncertainties on the design and performance of energy systems is described and discussed.Climate resilience is an emerging concept that is increasingly used to represent the durability and stable performance of energy systems against extreme climate events.However,it has not yet been adequately explored and widely used,as its definition has not been clearly articulated and assessment is mostly based on qualitative aspects.This study reveals that a major limitation in the state-of-the-art is the inadequacy of climate change adaptation approaches in designing and preparing urban energy systems to satisfactorily address plausible extreme climate events.Furthermore,the complexity of the climate and energy models and the mismatch between their temporal and spatial resolutions are the major limitations in linking these models.Therefore,few studies have focused on the design and operation of urban energy infrastructure in terms of climate resilience.Considering the occurrence of extreme climate events and increasing demand for implementing climate adaptation strategies,the study highlights the importance of improving energy system models to consider future climate variations including extreme events to identify climate resilient energy transition pathways.

关键词： climate resilience climate change adaptation urban energy systems renewable energy extreme events decentralized generation

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Ship behavior prediction via trajectory extraction-based clustering for maritime situation awareness

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Journal of Ocean Engineering and Science 2022年第1期7卷 1-13页

作者： Brian Murray LokukalugePrasad.perera UiT The Arctic University of Norway TromsøNorway

This study presents a method in which historical AIS data are used to predict the future trajectory of a se-lected vessel.This is facilitated via a system intelligence-based approach that can be subsequently utilized to provide enhanced situation awareness to navigators and future autonomous ships,aiding proactive col-lision avoidance.By evaluating the historical ship behavior in a given geographical region,the method applies machine learning techniques to extrapolate commonalities in relevant trajectory segments.These commonalities represent historical behavior modes that correspond to the possible future behavior of the selected vessel.Subsequently,the selected vessel is classified to a behavior mode,and a trajectory with respect to this mode is predicted.This is achieved via an initial clustering technique and subsequent tra-jectory extraction.The extracted trajectories are then compressed using the Karhunen-Loéve transform,and clustered using a Gaussian Mixture Model.The approach in this study differs from others in that tra-jectories are not clustered for an entire region,but rather for relevant trajectory segments.As such,the extracted trajectories provide a much better basis for clustering relevant historical ship behavior modes.A selected vessel is then classified to one of these modes using its observed behavior.Trajectory predic-tions are facilitated using an enhanced subset of data that likely correspond to the future behavior of the selected vessel.The method yields promising results,with high classification accuracy and low prediction error.However,vessels with abnormal behavior degrade the results in some situations,and have also been discussed in this study.

关键词： Maritime situation awareness Ship navigation Trajectory prediction Collision avoidance Machine learning Unsupervised learning AIS

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Porosity of bimodal and trimodal sediment mixtures

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International Journal of Sediment Research 2022年第2期37卷 258-271页

作者： Chamil perera Weiming Wu Ian Knack department of Civil and Environmental Engineering Clarkson University

This study focuses on the prediction of the porosity of nonuniform sediment mixtures,considering the effects of particle packing.A random particle packing model has been developed for the porosity of bimodal mixtures by extending the existing random particle filling theory.Coefficients in the developed model are calibrated by fitting the model to measured data for a variety of bimodal mixtures,including spherical glass particles,rounded quarry grains,and natural sediments.The model coefficients are found to be functions of the diameter ratio of coarse and fine particles,separately for spherical glass particles and natural sediments due to differences in particle shapes.The bimodal mixture model is then extended to trimodal particle mixtures in three approaches:two based on serial packing and one based on random packing.These models are tested against experimental data of six trimodal mixtures with spherical glass beads.The results show that the random packing model and the fine-medium-coarse particle serial packing model predict well the observed trimodal mixture porosities.

关键词： Porosity Particle filling Particle packing Bimodal mixture Trimodal mixture

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Mat hematical modeling and analysis of innate and humoral immune responses to dengue infections

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International Journal of Biomathematics 2019年第7期12卷 95-110页

作者： Sulanie perera S.S.N.perera Research and development Center for Mathematical Modeling Faculty of ScienceUniversity of ColomboColombo 3Sri Lanka

dengue is an acute arthropode-borne virus,belonging to the family Flaviviridae.Currently,there are no vaccines or treatments available against dengue.Thus it is important to understand the dynamics of dengue in order to control the infection.In this paper,we study the long-term dynamics of the model that is presented in[S.d.Peera and S.S.N.perera,Simulation model for dynamics of dengue with innate and humoral immune responses,Comput.Math.Methods Med.2018(2018)8798057,18 pp.doi:10.1155/2018/8798057]which describes the interaction of virus with infected and uninfected cells in the presence of innate and humoral immune responses.It was found the model has three equilibria,namely:infection free equilibrium,no immune equilibrium and endemic equilibrium,then analyzed its stability analytically.The analytical findings of each model have been exemplified by numerical simulations.Given the fact that intensity of dengue virus replication at early times of infection could determine clinical outcomes,it is important to understand the impact of innate immunity,which is believed to be the first line of defense against an invading pathogen.For this we carry out a simulation case study to investigate the importance of innate immune response on dengue virus dynamics.A comparison was done assurming that innate immunity was active;innate immunity was in quasi-steady state and innate immunity was inactive during the virus replication process.By a further analysis of the qualitative behavior of the quasi-steady state,it was observed that innate immune response plays a pivotal role in dengue virus dynamics.It can change the dynamical behavior of the system and is essential for the virus clearance.

关键词： dengue humoral inate equilibrium stability quasi-steady state

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未固结流砂地层采油过程中出砂情况模拟实验

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石油勘探与开发 2017年第5期44卷 811-816页

作者： perera M S A RANJITH P G RATHNAWEERA T d dE SILVA G P d LIU T department of Civil Engineering Monash University department of Infrastructure Engineering The University of Melbourne

为了研究未固结流砂储集层在采油过程中的出砂情况和影响出砂的主要因素,进行了不同条件下的出砂过程模拟实验。使用水洗白砂、黏土(高岭土)和蒸馏水制成未固结流砂地层模型,利用新开发的出砂模拟装置进行了模拟实验,并分析了作用于地... 详细信息

为了研究未固结流砂储集层在采油过程中的出砂情况和影响出砂的主要因素,进行了不同条件下的出砂过程模拟实验。使用水洗白砂、黏土(高岭土)和蒸馏水制成未固结流砂地层模型,利用新开发的出砂模拟装置进行了模拟实验,并分析了作用于地层的拖曳力和地层胶结特征对出砂的影响。研究表明,随着拖曳力的增加,出砂速度和产油速度都加快;随着胶结物含量的增加,出砂量和产油量明显降低,甚至在胶结物含量较高的情况下出砂量几乎为零。地层压力大的油藏在开采期间由于产生了较大的拖曳力更可能出砂,而拖曳力和有效地层应力共同影响油藏的总体产油量。可以根据地层黏土含量估计出砂情况,从而通过采取适当的防砂措施尽可能减少出砂量。某些情况下油藏比气藏更容易出砂。

关键词：流砂地层出砂采油工艺黏土含量胶结程度拖曳力

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Potential applications of 7 Tesla magnetic resonance imaging in paediatric neuroimaging:Feasibility and challenges

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World Journal of Clinical Pediatrics 2024年第2期13卷 1-6页

作者： Arosh S perera Molligoda Arachchige Letterio S Politi Final Year Medical Student Faculty of MedicineHumanitas UniversityPieve Emanuele 20089Italy department of Neuroradiology IRCCS Humanitas Research HospitalRozzano 20089MilanItaly department of Biomedical Sciences Humanitas UniversityPieve Emanuele 20072MilanItaly

The integration of 7 Tesla magnetic resonance imaging(7 T MRI)in adult patients has marked a revolutionary stride in radiology.In this article we explore the feasibility of 7 T MRI in paediatric practice,emphasizing its feasibility,applications,challenges,and safety considerations.The heightened resolution and tissue contrast of 7 T MRI offer unprecedented diagnostic accuracy,particularly in neuroimaging.Applications range from neuro-oncology to neonatal brain imaging,showcasing its efficacy in detecting subtle structural abnormalities and providing enhanced insights into neurological conditions.despite the promise,challenges such as high cost,discomfort,and safety concerns necessitate careful consideration.Research suggests that,with precautions,7 T MRI is feasible in paediatrics,yet ongoing studies and safety assessments are imperative.

关键词： 7 Tesla magnetic resonance imaging Pediatric imaging Feasibility Challenges

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design of a Vibration Sensor Based Train Arrival detection System to Prevent Elephant-Train Accidents in Sri Lanka

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Instrumentation 2020年第4期7卷 40-47页

作者： Nuwantha.d.KULARATHNA Sisaara perera Institute of Engineers Sri Lanka College of Engineering department of Electrical and Computer Engineering The Open University of Sri Lanka

At present,Sri Lanka is home to about 5,000-6,000 wild elephants roaming over close to 70%of the country’s land.despite this blessing,around 150 elephants die each year due to many reasons.The main reasons for the altercations between humans and elephants are the drastic increase in the human population,human encroachment upon elephant territory for agriculture and settlements and unplanned development and transportation efforts.Elephants are long lived herbivores,and their survival depends upon regular migration over large distances to search for food,water,and social and reproductive partners.According to the Sri Lanka railways the average number of elephants that get killed due to elephant-railway accidents is about 9 per year.As a solution for this problem,we have proposed a novel system to pass a signal to indicate the train arrival.The proposed system detects the vibration of the locomotives and after detecting the vibration,alarm system will generate a high frequency signal within the frequency range,where the elephants are sensitive.The proposed system is a low cost device and this can be placed anywhere at any time.Moreover,this project aims to protect elephants from being harmed which usually happen due to various human activities.

关键词： Herbivore Sri Lanka Railway Locomotives

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Electrical and electronic waste (e-waste) recycling and management strategies in South Asian region: a systematic review from Sri Lankan context

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Waste disposal and Sustainable Energy 2023年第4期5卷 559-575页

作者： Shakya Widanapathirana Iddamalgoda Jayawardanage Judi Udari Nisansala perera Bellanthudawage Kushan Aravinda Bellanthudawa department of Engineering and Mathematics Sheffield Hallam UniversitySheffieldS11WBUK department of Agricultural Engineering Faculty of AgricultureUniversity of RuhunaMapalanaMatara81100Sri Lanka

Electrical and electronic waste(e-waste)has become a global crisis.Managing this ever-growing problem has become very critical and yet challenging,especially in the South Asian region;otherwise,it may undermine the sustainability of development and growth of numerous industries.Hence,to explore the current context of e-waste management,recycling,and strategies in Sri Lanka,we conducted a systematic literature review process using peer-reviewed research articles retrieved from Google Scholar database.We searched for articles containing keywords such as“e-waste”,“management strategies and recycling”,and“Sri Lanka”.We screened out papers(n=20)selected from papers(n=327)initially retrieved over a 17 period of time(2005–2022).The analysis of the screened articles showed that the main challenges to successful e-waste management were a lack of management strategies,policies,and inadequate recycling practices as well as identifying the potential and opportunities to actively enhance the comprehensive awareness,collection,storage,proper disposal,and other e-waste management steps in Sri Lanka.Further,the study identified technological,financial,socio-economic,and institutional sectors as fundamental sectors to formulate a strategic plan for e-waste management.Also,the study suggests that enacting laws to practice and adopt e-waste management,establishing central command and management institutes to control all e-waste management bodies,providing financial assistance to informal e-waste collectors and recyclers,and introducing e-waste management to school curricula are some of the possible actions that can be taken along with enhancing the awareness of e-waste management.

关键词： Collection and recycling disposal E-waste management strategies Sri Lanka Sustainable development goals

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Ship performance and navigation data compression and communication under autoencoder system architecture

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Journal of Ocean Engineering and Science 2018年第2期3卷 133-143页

作者： Lokukaluge P.perera B.Mo UiT The Arctic University of Norway TromsoNorway SINTEF Ocean TrondheimNorway

Modern vessels are designed to collect,store and communicate large quantities of ship performance and navigation information through complex onboard data handling processes.That data should be transferred to shore based data centers for further analysis and storage.However,the associated transfer cost in large-scale data sets is a major challenge for the shipping industry,today.The same cost relates to the amount of data that are transferring through various communication networks(i.***.satellites and wireless networks),i.***.between vessels and shore based data centers.Hence,this study proposes to use an autoencoder system architecture(i.e.a deep learning approach)to compress ship performance and navigation parameters(i.***.reduce the number of parameters)and transfer through the respective communication networks as reduced data sets.The data compression is done under the linear version of an autoencoder that consists of principal component analysis(PCA),where the respective principal components(PCs)represent the structure of the data set.The compressed data set is expanded by the same data structure(i.***.an autoencoder system architecture)at the respective data center requiring further analyses and storage.A data set of ship performance and navigation parameters in a selected vessel is analyzed(i.***.data compression and expansion)through an autoencoder system architecture and the results are presented in this study.Furthermore,the respective input and output values of the autoencoder are also compared as statistical distributions and sample number series to evaluate its performance.

关键词： Autoencoder Ship performance and navigation information Ship energy efficiency data compression data communication Principal component analysis

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