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Biomedical and Environmental Sciences 2009年第3期22卷 201-209页

作者： p.w.anton perera College of Environmental and Resource Sciences Zhejiang University

Objective To investigate the struvite precipitation under constant and non-constant pH conditions and to test a stainless steel device under different operating regimes to maximize the recovery of struvite. Methods The molar ratio of NH4^＋： Mg^2＋ pO43 was adjusted to 1： 1.2：1.2 and pH was elevated to 9.0. The absorbance measurement was used to trace the process of struvite crystallization. wastewater and precipitate analysis was done by standard analytical methods. Results The pH constant experiment reported a significantly higher struvite precipitation （24.6±0.86 g） than the non-constant pH experiment （19.8±1.86 g）. The SAR ranged from 5.6 to 8.2 g m^-2h^-1 to 3.6-4.8 g m^-2h^-1 in pH constant and non-constant experiments, respectively. The highest struvite deposit on the device was found in regime 3 followed by in regimes 2 and 4. The highest pO4^3- （97.2%） and NH4^＋（71%） removal was reported in the R1 regime. None of the influent Cu^2＋ or Zn^2＋ was precipitated on the device. Conclusion A higher struvite yield is evident in pH constant experiments. Moreover, the stainless steel device facilitates the isolation of heavy metal free pure （around 96%） struvite from swine waste biogas digester effluent contaminated with Cu^2＋ and Zn^2＋ and the highest yield is attainable with the device operating at 50 rpm with agitation by a magnetic stirrer.

关键词： Struvite recovery Accumulation device Swine waste Constant pH Struvite precipitation

Recovery of Nitrogen and phosphorous as Struvite From Swine waste Biogas Digester Effluent

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Biomedical and Environmental Sciences 2007年第5期20卷 343-350页

作者： p. w. anton perera College of Environmental and Resource Sciences Zhejiang University

Objective To investigate the feasibility of nitrogen and phosphorus recovery from swine waste biogas digester effluent and the effects of pH and NH4^＋： Mg2^＋： pO4^3- molar ratio on its precipitation. Methods precipitation experiments with swine waste biogas digester effluent were conducted at pH 7.5, 8.0, 8.5, and 9.0 together with NH4^＋： Mg^2＋： pO4^3- molar ratios 1： 0.2： 0.08, 1： 1： 1, and 1： 1.5： 1.5. Chemical and X-ray diffraction （XRD） analysis were done to determine the composition of the precipitate. Results The highest removal and recovery of NH4^＋ and pO4^3- were achieved at pH 9.0 in each experiment. The elevation of pH to 9.0 alone could decrease the initial pO4^3- concentration from 42 mg L^-1 to 4.7 mg L-1 and 89.2% pO4^3- recovery was achieved. The pH-molar ratio combination 9.0-1： 1.5： 1.5 effected 76.5% NH4^＋ and 68.5% pO4^3- recovery. The molar ratio of 1： 1： 1 together with pH elevation to 9.0 was determined to be the optimum combination for both NH4＋ and pO4^3- removal as it recovered over 70% and 97% of the initial NH4^＋ and pO4^3-, respectively. Conclusions Nitrogen and phosphorus can be recovered from biogas digester effluent as struvite.

关键词： phosphate recovery Ammonium nitrogen recovery Biogas Struvite Swine waste

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 *** data should be transferred to shore based data centers for further analysis and ***,the associated transfer cost in large-scale data sets is a major challenge for the shipping industry,*** same cost relates to the amount of data that are transferring through various communication networks(*** and wireless networks),*** vessels and shore based data ***,this study proposes to use an autoencoder system architecture(i.e.a deep learning approach)to compress ship performance and navigation parameters(*** the number of parameters)and transfer through the respective communication networks as reduced data *** 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 *** compressed data set is expanded by the same data structure(*** 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(*** compression and expansion)through an autoencoder system architecture and the results are presented in this ***,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

Ship speed power performance under relative wind profiles in relation to sensor fault detection

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Journal of Ocean Engineering and Science 2018年第4期3卷 355-366页

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

Statistical data analysis and visualization approaches to identify ship speed power performance under relative wind(*** wind)profiles are considered in this *** performance and navigation data of a selected vessel are analyzed,where various data anomalies,*** related erroneous data conditions,are *** erroneous data conditions are investigated and several approaches to isolate such situations are also presented by considering appropriate data visualization ***,the cleaned data are used to derive various relationships among ship performance and navigation parameters that have been visualized in this study,*** results show that the wind profiles along ship routes can be used to evaluate vessel performance and navigation conditions by assuming the respective sea states relate to their wind ***,the results are useful to derive appropriate mathematical models that represent ship performance and navigation *** mathematical models can be used for weather routing type applications(*** planning),where the respective weather forecast can be used to derive optimal ship routes to improve vessel performance and reduce fuel *** study presents not only an overview of statistical data analysis of ship performance and navigation data but also the respective challenges in data anomalies(*** data intervals and sensor faults)due to onboard sensors and data handling ***,the respective solutions to such challenges in data quality have also been presented by considering data visualization approaches.

关键词： Speed power performance Data anomaly detection Sensor fault identification weather routing Statistical data analysis Ship wind profile.

Response of tropical avifauna to visitor recreational disturbances: a case study from the Sinharaja world Heritage Forest, Sri Lanka

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Chinese Birds 2016年第3期7卷 142-154页

作者： Nilusha S.Alwis priyan perera Nihal p.Dayawansa Department of Forestry and Environmental Science University of Sri Jayewardenepura Department of Zoology University of Colombo

Background: we investigated the impact of human recreational disturbances on the distribution of birds along a popular nature trail in Sinhararja world Heritage Forest, Sri Lanka. It was hypothesized that visual and noise stimuli caused by the presence of humans affect the distribution of avifauna associated with this nature ***: Nine circular plots of 25 m fixed-radius laid along the trail(0 m), and 18 plots laid perpendicular to the trail at 75 and 150 m intervals, were studied from March 2013 to January 2014. The degree of human recreational disturbances was assessed in terms of visitor group size(visual disturbance) and their noise level(sound disturbance). These disturbances were categorized along a four-point scale(no human disturbance, low, medium and high disturbance). The relationship between disturbance levels and the abundance of birds was statistically ***: ANOVA results revealed that the abundance of birds differed significantly under various intensities of recreational disturbances at each distance level. A significant negative correlation between abundance of birds and intensity of disturbance at 0 m distance suggests an avoidance of edge habitats by birds in the presence of humans. Abundance of birds increased at the 75 and 150 m distance levels with increasing disturbances occurring at the trail. Significant negative correlations were further observed between disturbance level and the abundance of birds in ground/understory and sub-canopy vertical strata of the forest at 0 m ***: Under high levels of recreational disturbance occurring at this trail, the abundance of birds near the trail declined significantly, while bird abundance in the interior of the forest increased. The sensitivity of individual bird species to visitor disturbances varied with the vertical stratum of the forest they usually occupy. Birds occupying the ground, understory and sub-canopy are particularly sensitive to recreational disturbances

关键词： Recreational disturbances Ecotourism Tropical birds Sinharaja world Heritage Forest Habituation

Molecular cloning and comparative analysis of transcripts encoding chemosensory proteins from two plant bugs, Lygus lineolaris and Lygus hesperus

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Insect Science 2020年第3期27卷 404-424页

作者： J.Joe Hull Omaththage p.perera Mei-Xian wang USDA-ARS Arid Land Agricultural Research Center MaricopaArizonaUSA USDA-ARS Southern Insect Management Research UnitStonevilleMississippiUSA College of Animal Sciences Zhejiang UniversityHangzhouChina

Chemosensory proteins(CSps)are soluble carrier proteins typically characterized by a six‐helix bundle structure joined by two disulfide bridges and a conserved Cys spacing pattern(C1‐X6‐8‐C2‐X16‐21‐C3‐X2‐C4).CSps are functionally diverse with reported roles in chemosensation,immunity,development,and *** expand our molecular understanding of CSp function in plant bugs,we used recently developed transcriptomic resources for Lygus lineolaris and Lygus hesperus to identify 17 and 14 CSp‐like sequences,*** Lygus CSps are orthologous and share significant sequence identity with previously annotated *** of the CSps are predicted to deviate from the typical CSp structure with either five or seven helical segments rather than *** seven helix CSp is further differentiated by an atypical C3‐X3‐C4 Cys spacing *** transcriptase pCR‐based profiling of CSp transcript abundance in adult *** tissues revealed broad expression for most of the CSps with antenna specific expression limited to a subset of the *** sequence analyses and homology modeling suggest that variations in the amino acids that comprise the Lygus CSp binding pockets affect the size and nature of the ligands accommodated.

关键词： chemosensation chemosensory protein homology modeling Lygus plant bug mired transcriptome

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 ***,there are no vaccines or treatments available against *** it is important to understand the dynamics of dengue in order to control the *** this paper,we study the long-term dynamics of the model that is presented in[*** and ***,Simulation model for dynamics of dengue with innate and humoral immune responses,*** Med.2018(2018)8798057,18 ***:10.1155/2018/8798057]which describes the interaction of virus with infected and uninfected cells in the presence of innate and humoral immune *** was found the model has three equilibria,namely:infection free equilibrium,no immune equilibrium and endemic equilibrium,then analyzed its stability *** analytical findings of each model have been exemplified by numerical *** 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 *** 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 *** 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 *** 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

In silico Analysis of osr40c1 promoter Sequence Isolated from Indica Variety pokkali

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Rice science 2017年第4期24卷 228-234页

作者： w.S.I.deSILVA M.M.N.perera K.L.N.S.perera A.M.wICKRAMASURIYA G.A.U.JAYASEKERA Department of plant Sciences Faculty of ScienceUniversity of ColomboColombo 00300Sri Lanka Genetech Molecular Diagnostics and School of Gene Technology Colombo 00800Sri Lanka

The promoter region of a drought and abscisic acid （ABA） inducible gene, osr40c1, was isolated from a salt-tolerant indica rice variety pokkali, which is 670 bp upstream of the putative translation start codon. In silico promoter analysis of resulted sequence showed that at least 15 types of putative motifs were distributed within the sequence, including two types of common promoter elements, TATA and CAAT boxes. Additionally, several putative cis-acing regulatory elements which may be involved in regulation of osr40c1 expression under different conditions were found in the 5′-upstream region of osr40c1. These are ABA-responsive element, light-responsive elements （ATCT-motif, Box I, G-box, GT1-motif, Gap-box and Sp1）, myeloblastosis oncogene response element （CCAAT-box）, auxin responsive element （TGA-element）, gibberellin-responsive element （GARE-motif） and fungal-elicitor responsive elements （Box E and Box-w1）. A putative regulatory element, required for endosperm-specific pattern of gene expression designated as Skn-1 motif, was also detected in the pokkali osr40c1 promoter region. In conclusion, the bioinformatic analysis of osr40c1 promoter region isolated from indica rice variety pokkali led to the identification of several important stress-responsive cis-acting regulatory elements, and therefore, the isolated promoter sequence could be employed in rice genetic transformation to mediate expression of abiotic stress induced genes.

关键词： osr40c1 promoter cis-acting regulatory element rice

Role of photon-counting computed tomography in pediatric cardiovascular imaging

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world Journal of Clinical pediatrics 2025年第1期14卷 55-62页

作者： Arosh S perera Molligoda Arachchige Yash Verma Faculty of Medicine Humanitas UniversityPieve Emanuele 20072Italy Department of Radiology Mayo ClinicRochesterMN 55905United States

photon-counting computed tomography(pCCT)represents a significant advancement in pediatric cardiovascular *** CT systems employ energy-integrating detectors that convert X-ray photons into visible light,whereas pCCT utilizes photon-counting detectors that directly transform X-ray photons into electric *** direct conversion allows photon-counting detectors to sort photons into discrete energy levels,thereby enhancing image quality through superior noise reduction,improved spatial and contrast resolution,and reduced *** pediatric applications,pCCT offers substantial benefits,including lower radiation doses,which may help reduce the risk of malignancy in pediatric patients,with perhaps greater potential to benefit those with repeated exposure from a young *** spatial resolution facilitates better visualization of small structures,vital for diagnosing congenital heart ***,pCCT’s spectral capabilities improve tissue characterization and enable the creation of virtual monoenergetic images,which enhance soft-tissue contrast and potentially reduce contrast media *** clinical results indicate that pCCT provides superior image quality and diagnostic accuracy compared to conven-tional CT,particularly in challenging pediatric cardiovascular *** pCCT technology matures,further research and standardized protocols will be essential to fully integrate it into pediatric imaging practices,ensuring optimized diagnostic outcomes and patient safety.

关键词： Cardiovascular photon-counting detectors pediatric photon-counting computed tomography Computed tomography

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 *** 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 *** evaluating the historical ship behavior in a given geographical region,the method applies machine learning techniques to extrapolate commonalities in relevant trajectory *** commonalities represent historical behavior modes that correspond to the possible future behavior of the selected ***,the selected vessel is classified to a behavior mode,and a trajectory with respect to this mode is *** is achieved via an initial clustering technique and subsequent tra-jectory *** extracted trajectories are then compressed using the Karhunen-Loéve transform,and clustered using a Gaussian Mixture *** approach in this study differs from others in that tra-jectories are not clustered for an entire region,but rather for relevant trajectory *** 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 *** predic-tions are facilitated using an enhanced subset of data that likely correspond to the future behavior of the selected *** method yields promising results,with high classification accuracy and low prediction ***,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