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Stability Limitation and Analytical Evaluation of Voltage Droop Controllers for VSC MTDC

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CSEE Journal of power and Energy Systems 2018年第2期4卷 238-249页

作者： Wenyuan Wang Mike barnes Ognjen Marjanovic GE Grid Solutions StaffordST174LXU.K School of Electrical and Electronic Engineering The University of ManchesterManchesterM139PLU.K

This paper presents a systematic analysis of DC voltage stability of a multi-terminal VSC-HVDC(MTDC)system,with the emphasis on a comparative study of the most ubiquitous droop control *** paper introduces a general framework for the analysis of various droop control configurations employed in MTDC *** framework is then used to compare leading droop control configurations in terms of their impact on the relative stability,performance and robustness of the overall MTDC system.A generalized analytical MTDC model that contains detailed models of AC and DC system components is *** imposed by DC power flow,DC inductor,cable modeling and AC network impedance on DC system stability are *** and multivariable frequency response analysis and eigenvalue analysis are applied to open-loop and closed-loop models to compare the stability and robustness of five leading droop controllers,with the focus on feedback signal selection and controller *** paper also proposes an active stabilizing controller,which takes the form of a modified constant power control,to enhance the controllability and robustness of the DC voltage control.

关键词： Droop control mathematical modeling MTDC control stability VSC HVDC

Biofumigation: An alternative strategy for the control of plant parasitic nematodes

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Journal of Integrative Agriculture 2020年第7期19卷 1680-1690页

作者： Rebecca Jean barnes BRENNAN Samantha GLAZE-CORCORAN Robert WICK Masoud HASHEMI University of Massachusetts Amherst Cranberry Station East WarehamMassachusetts 02538USA Stockbridge School of Agriculture University of Massachusetts AmherstAmherstMA 01003USA

plant-parasitic nematodes wreak havoc on the yield and quality of crops *** from these pests is estimated to exceed US$100 bllion annually but is likely higher due to *** damage may be catastrophic,but historically the solution has been damaging as *** of the synthetic nematicide methyl bromide(MBr)poses risks to the environment and to human ***,the use of plant material and naturally produced compounds to control pests,is an increasingly feasible method of pest *** process acts through the growth or incorporation of plant material into the soil,that,over the course of its degradation,releases glucosinolates that break down into nematotoxic *** secondary plant metabolites exist naturally in commonly grown plants,most of which belong to the Brassicaceae *** endeavors have increasingly explored the potential of *** reaction of target pests,the selection of biofumigant,and ideal environments for efficacy continue to be *** review seeks to provide a cost and benefit assessment of the status of biofumigation for the control of plant-parasitic nematodes as an alternative to conventional methyl bromide usage.

关键词： biofumigation plant-parasitic nematode Brassicaceae isothiocyanate methyl bromide

Signal processing for Fast Fault Detection in HVDC Grids

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CSEE Journal of power and Energy Systems 2018年第4期4卷 469-478页

作者： Willem Leterme Mike barnes Dirk Van Hertem EnergyVille/Electa research group Electrical Engineering Department ESATKU LeuvenBelgium power Conversion Research Group School of Electrical and Electronic EngineeringUniversity of ManchesterManchester M139PLUK

For multiterminal or meshed Voltage Source Converter(VSC)High-voltage Direct Current(HVDC)systems,high speed protection against DC faults is essential,as power electronic components cannot withstand the rapidly increasing fault currents which would otherwise *** proposed DC fault detection methods were developed based on time domain simulations in EMT-type software,which requires considerable modeling and computational efforts and results in methods specifically designed for the HVDC grid under *** simplify the initial design of DC fault detection methods,this paper proposes general guidelines based on fundamental theory and offers a reduced modeling ***,the impact of non-ideal measurements is investigated and a method to choose the filters that optimally discriminate these fault signals from noise,is *** approach was evaluated in a case study on fault detection in a realistically dimensioned HVDC *** paper shows that the initial design of fast fault detection methods can be based on the relatively simple proposed guidelines and reduced *** paper furthermore shows that a sufficiently high sampling frequency and a filter matched to the fault signal enable fault detection within hundreds of microseconds and discrimination of DC faults from transients not related to DC faults.

关键词： HVDC matched filter measurement power system faults power system transients

Effect of Mushroom Extract Hericium erinaceus on Spatial Memory and Morphology of Neurons in the CA1 and CA3 Regions of the Hippocampus in Ovariectomized Rats

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Open Journal of Veterinary Medicine 2024年第7期14卷 163-179页

作者： Lucia Garcia-Delgado Mariana Monserrath Verdía-Venegas Jacinto Bañuelos-pineda Esther Albarrán-Rodríguez Guillermo Nolasco-Rodriguez José Ricardo Cuellar-pérez Sergio Fausto-Guerra Manuel Rosales-Cortés Master in Behavioral Sciences Institute of Neurosciences University of Guadalajara Zapopan Mexico Department of Veterinary Medicine Division of Veterinary Sciences CUCBA University of Guadalajara Zapopan Mexico Botany and Zoology Laboratory CUCBA University of Guadalajara Zapopan Mexico

Various studies indicate that low levels of estradiol negatively impact cognitive abilities. Extracts from the fungus Hericium erinaceus (HE) contain bioactive components that promote the proper functioning of the nervous system and potential effects on protection against neurodegenerative diseases, including dementia and motor dysfunctions. The objective was to evaluate the effects of the administration of the HE mushroom extract on visuospatial memory and morphology of neurons in the CA1 and CA3 regions of the hippocampus in ovariectomized rats. 40 young Wistar rats weighing 90 ± 10 g BW were used, which were distributed into four groups of 10 animals;Control Group, non-ovariectomized and untreated rats;Group E2, ovariectomized rats treated with estradiol (2 μg/kg/body weight);Group HE, ovariectomized rats treated with the extract of the fungus Hericium erinaceus (0.5 mg/kg body weight) and Group Ovx/ST, ovariectomized rats, without treatment. The animals were tested in the barnes and Open Field maze, then they were sacrificed, and their brains were obtained to perform a histological analysis of neuronal morphology in the CA1 and CA3 areas of the hippocampus. The most outstanding results showed that the Ovx/ST group recorded the longest time to arrive at the escape box and stay in the barnes maze. A correlation was observed between neuronal damage and function;in the groups that did not present satisfactory performance in the maze tests, morphological alterations were identified such as the presence of some neuronal somata with degeneration characteristics such as pyknosis, nuclear basophilia and shrinkage of the cells. Its soma, as well as a decrease in the nuclear area of CA1 and CA3 neurons. It is concluded that the fungus Hericium erinaceus exerted a neuroprotective effect on the neuronal bodies of the hippocampus, associated with better performance in the visuospatial recognition memory test.

关键词： Ovariectomized Rats Ovarian Hypofunction Estradiol Hericium erinaceus barnes Circular Labyrinth Open Field Labyrinth

Element mapping the Merensky Reef of the Bushveld Complex

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Geoscience Frontiers 2021年第3期12卷 259-278页

作者： William Smith Wolfgang Maier Stephen barnes Gareth Moorhead David Reid Bartosz Karykowski School of Earth and Ocean Sciences Cardiff UniversityCardiff CF240DEUnited Kingdom CSIRO Mineral Resources Perth 6160Australia CSIRO ClaytonVictoriaAustralia University of Cape Town South Africa Fugro Germany Land GmbH 12555 BerlinGermany

The Merensky Reef hosts one of the largest pGE resources *** has been exploited for nearly 100 years,yet its origin remains *** the present study,we characterised eight samples of the reef at four localities in the western Bushveld Complex using micro-X-ray fluorescence and field emission scanning electron *** results indicate that the Merensky Reef formed through a range of diverse *** exhibited by chromite grains at the base of the reef are consistent with supercooling and in situ *** local thickening of the Merensky chromitite layers within troughs in the floor rocks is most readily explained by granular *** and deformation textures in pyroxenes of the Merensky pegmatoid bear testament to recrystallisation and *** footwall rocks to the reef contain disseminations of pGE rich sulphides as well as olivine grains with peritectic reaction rims along their upper margins suggesting reactive downward flow of silicate and sulphide ***-hosted melt inclusions containing Cl-rich apatite,sodic plagioclase,and phlogopite suggest the presence of highly evolved,volatile-rich *** reverse zonation of cumulus plagioclase in the footwall of the reef indicates dissolution or partial melting of plagioclase,possibly triggered by flux of heat,acidic fluids,or hydrous ***,these data suggest that the reef formed through a combination of magmatic,hydrodynamic and hydromagmatic processes.

关键词： Merensky Reef Bushveld Complex Magmatic sulphide platinum-group elements pGE Anorthosite

A Systematic Literature Review of Funding for Higher Education Institutions in Developed Countries

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Frontiers of Education in China 2016年第4期11卷 519-542页

作者： Qilong ZHANG Ruth barnes KANG Ning Faculty of Health Education and HumanitiesWaiariki Institute of TechnologyRotoruaNew Zealand China Education publishing&Media Holdings Co.Ltd. Beijing 100089China

Resource allocation and funding in higher education is crucial to the success of reform and transformation of our higher education *** a view to identifying trends and best practices in the area,utilizing a method of systematic literature review,we have critically reviewed relevant theories and practices from developed counties that are covered in the scholarly literature published in English in the past 10 *** review has revealed:(1)Several universal trends have exerted a decisive impact on resource allocation in higher education,for example,funding reduction and tuition fee increases,performancebased funding,privatization,corporatization,and internationalization;(2)Several theories underpin key research in the area,for example,new institutional economics,resource dependence theory,and political economy;(3)Several controversial issues have made their way into public debate,for example,higher education as a public good or private good,academic capitalism,educational equity,and the role of econometrics.

关键词： higher education resource allocation funding developed countries

Second and Third Trimester Fetal Death in the Setting of COVID-19: A California 2020 Case Series

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Maternal-Fetal Medicine 2022年第2期4卷 127-129页

作者： Rosalyn E.plotzker Similoluwa Sowunmi Valorie Eckert Emily barnes Van Ngo Lauren J.Stockman Chloe LeMarchand Umme-Aiman Halai Division of Communicable Disease Control Center for Infectious DiseaseCalifornia Department of Public Health(CDPH)RichmondCA 94804USA California Birth Defects Monitoring program Center for Family HealthCalifornia Department of Public Health(CDPH)RichmondCA 94804USA Los Angeles County Department of public Health Los AngelesCA 90012USA.

Maternal severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection in the second and third trimesters of pregnancy may impact fetal development via vertical transmission,complications of coronavirus disease 2019(COVID-19),or placental ***,potential associations between prenatal SARS-CoV-2 infection and fetal loss are not well *** case series of thirteen second and third trimester fetal losses reported by local public health departments to California’s state public health surveillance included maternal clinical and demographic characteristics as well as placental pathology,fetal autopsy reports,and coroner *** was no evidence that maternal COVID-19 disease severity,placental injury,or SARS-CoV-2 vertical transmission contributed to pregnancy ***,this case series is a limited sample;more research is needed to identify factors of prenatal SARS-CoV-2 that may contribute to fetal death in the second and third trimesters.

关键词： COVID-19 Fetal death prenatal infection Stillbirth

Review of different fault detection methods and their impact on pre-emptive VSC-HVDC dc protection performance

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High Voltage 2017年第4期2卷 211-219页

作者： Bin Chang Oliver Cwikowski Mike barnes Roger Shuttleworth Antony Beddard paul Coventry Global Energy Interconnection Research Institute Future Science ParkBeijing 102209People's Republic of China The University of Manchester Oxford RoadManchester M139PLUK National Grid National Grid HouseWarwick CV346DAUK

Multi-terminal voltage-sourced converters(VSC)high-voltage direct current(HVDC)transmission system is expected to play a vital role in future power *** with ac power transmission,dc transmission is more vulnerable to faults due to low dc-side impedances and sensitive power electronics in the *** protection issues must be tackled before any multi-terminal VSC-HVDC grid can be *** multi-terminal VSC-HVDC system is studied in detail using switching models for two-level converters,detailed equivalent models for the modular multi-level converters,detailed hybrid circuit breaker switching models and frequency-dependent phase models for dc *** such high-fidelity system models,a systematic study of HVDC fault protection methodologies in more detail than previous studies is *** is the first comprehensive study that includes pre-emptive circuit breaker *** results presented in this study underline the benefits of such a detailed treatment of the breaker,and of considering it as part of a fast power electronics system rather than isolated dc *** study identifies the best existing fault detection method and tests it *** order to further improve post-fault system recovery response,which is a key but often neglected part of previous studies,a novel bump-less transfer control has been implemented in the converters.

关键词： fault system power

Sutureless Implantation of Acoustic Transmitters in Rainbow Trout Exceeding 2% Tag-to-Body Ratio

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Advances in Bioscience and Biotechnology 2022年第6期13卷 265-271页

作者： Ashley Kelican Nathan Huysman Jill M. Voorhees Michael E. barnes South Dakota Department of Game Fish and Parks McNenny State Fish Hatchery Spearfish USA

A novel sutureless surgical technique has been successfully used to implant acoustic transmitters in relatively large rainbow trout Oncorhynchus mykiss with a tag-to-body-ratio of 0.88%. This study examined the same technique in smaller rainbow trout in two, 12-week trials comparing both sutured and sutureless surgical techniques. In the first trial using a tag-to-body-ratio of 1.9% ± 0.04%, tag retention was only 16.6% in fish without sutures, which was significantly lower than the 83.3% retention with sutured incisions. Similarly, in the second trial with a tag-to-body-ratio of 3.2% ± 0.03%, tag retention was 55.5% without sutures, which was significantly lower than the 90.0% retention using sutures. Mortality was not significantly different between treatments in either trial. The results of this study indicate that sutures must be used during surgeries to implant acoustic transmitters in relatively smaller fish with tag-to-body-ratios at or above 1.9%.

关键词： Rainbow Trout Oncorhynchus mykiss Surgery Acoustic Transmitter