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Articles 60721 - 60750 of 302638

Full-Text Articles in Physical Sciences and Mathematics

Combined Effects Of Allelochemical And Pesticide Treatment On The Growth Of Cucumber Plants, Samue Morgan Apr 2021

Combined Effects Of Allelochemical And Pesticide Treatment On The Growth Of Cucumber Plants, Samue Morgan

Spring Showcase for Research and Creative Inquiry

Allelochemicals are biochemicals produced by one plant that inhibits the success of other plants in its vicinity. These allelochemicals are sometimes produced naturally or as a result of stimulus or stress. Ferulic acid is a widespread allelochemical found in cucumbers (Cucumis sativus). Artificial inhibitory chemicals such as the pesticide zeta cypermethrin may create new interactions with ferulic acid. We found that cucumbers acclimate to ferulic acid over time while the inhibitory effects of pesticide remained relatively constant over 14 days.

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Chemical Analysis Of An Herbal Opioid, Lauren Johnson Apr 2021

Chemical Analysis Of An Herbal Opioid, Lauren Johnson

Spring Showcase for Research and Creative Inquiry

Different chromatography techniques were used to analyze the concentration of an active component, mitragynine, in kratom samples. The analysis also compared three different extraction methods, one using ultrasonification, the other two using a commercial at home espresso maker. Using gas chromatography mass spectrometry, and high performance liquid chromatography, comparisons between key compounds in the substances were determined and concentrations of mitragynine within the samples were calculated.

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Machine Learning Approach To Pattern Recognition In Nuclear Dynamics From The Ab Initio Symmetry-Adapted No-Core Shell Model, Oleksandr Molchanov Apr 2021

Machine Learning Approach To Pattern Recognition In Nuclear Dynamics From The Ab Initio Symmetry-Adapted No-Core Shell Model, Oleksandr Molchanov

Honors Theses

No abstract provided.

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Co2 Capturing Materials, Isaac Sanchez Apr 2021

Co2 Capturing Materials, Isaac Sanchez

Undergraduate Research Symposium 2021

Greenhouse gas emissions are one of, if not the major cause of global warming. With CO2 emissions rising annually, it is paramount to selectively capture and remove CO2 from flue gas. One method of capturing CO2 gas is via porous materials. Covalent organic frameworks (COFs) are porous materials which have been explored throughout this research. Two important features of COFs are the base unit linkage types (BULTs) and the functional groups attached to the organic linkers (OLs). The BULT used in this research was a covalent triazine framework (CTF) and the main functional group used in the …

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Synthesis Of Transfer Hydrogenation Catalysts Containing Unsymmetrical Bisphosphines, Nora Fritz Apr 2021

Synthesis Of Transfer Hydrogenation Catalysts Containing Unsymmetrical Bisphosphines, Nora Fritz

Undergraduate Research Symposium 2021

Asymmetric catalysis, where a metal catalyst is used to transform a substrate into a single enantiomer of product, has become a popular synthetic technique in both academic and industrial settings. An enantiomer is a single molecule with a unique three-dimensional shape with a mirror image not superimposable on the original. The chirality, or right or left-handedness, of compounds lead to applications important in the pharmaceutical and agrochemical industries. Commonly, a metal complex’s ability to create a product of a certain enantiomer relies on a chiral group being attached to the metal. However, having the chirality of a metal complex depend …

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How Much Has The Sun Influenced Northern Hemisphere Temperature Trends? An Ongoing Debate, Ronan Connolly, Willie Soon, Michael Connolly, Sallie Baliunas, Johan Berglund, C. John Butler, Rodolfo Gustavo Cionco, Ana G. Elias, Valery M. Fedorov, Hermann Harde, Gregory W. Henry, Douglas V. Hoyt, Ole Humlum, David R. Legates, Sebastian Lüning, Nicola Scafetta, Jan-Erik Solheim, László Szarka, Harry Van Loon, Víctor M. Velasco Herrera, Richard C. Willson, Hong Yan, Weijia Zhang Apr 2021

How Much Has The Sun Influenced Northern Hemisphere Temperature Trends? An Ongoing Debate, Ronan Connolly, Willie Soon, Michael Connolly, Sallie Baliunas, Johan Berglund, C. John Butler, Rodolfo Gustavo Cionco, Ana G. Elias, Valery M. Fedorov, Hermann Harde, Gregory W. Henry, Douglas V. Hoyt, Ole Humlum, David R. Legates, Sebastian Lüning, Nicola Scafetta, Jan-Erik Solheim, László Szarka, Harry Van Loon, Víctor M. Velasco Herrera, Richard C. Willson, Hong Yan, Weijia Zhang

Information Systems and Engineering Management Research Publications

In order to evaluate how much Total Solar Irradiance (TSI) has influenced Northern Hemisphere surface air temperature trends, it is important to have reliable estimates of both quantities. Sixteen different estimates of the changes in TSI since at least the 19th century were compiled from the literature. Half of these estimates are "low variability" and half are "high variability". Meanwhile, five largely-independent methods for estimating Northern Hemisphere temperature trends were evaluated using: 1) only rural weather stations; 2) all available stations whether urban or rural (the standard approach); 3) only sea surface temperatures; 4) tree-ring widths as temperature proxies; 5) …

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Environmental Health - The Impact Of Oil Sands Mining On Peatland Ecosystems In Alberta, Canada, Melanie A. Vile Apr 2021

Environmental Health - The Impact Of Oil Sands Mining On Peatland Ecosystems In Alberta, Canada, Melanie A. Vile

Sustainability Research & Practice Seminar Presentations

No abstract provided.

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Automl For Anomaly Detection Of Time Series And Sequences Of Short Text, Cynthia Freeman Apr 2021

Automl For Anomaly Detection Of Time Series And Sequences Of Short Text, Cynthia Freeman

Computer Science ETDs

Automated approaches for parameter and algorithm selection greatly democratize fields such as machine learning, saving time and money as hiring experts can be prohibitively expensive. Unfortunately, anomaly detection is difficult to automate due to subjectivity and class imbalance. An anomaly detection system is presented that incorporates human-in-the-loop techniques and is dynamic, scalable, and able to work with non-annotated data. By focusing on meta-features of the input data, the system can intelligently choose the most promising anomaly detection methods. The system is agnostic to the medium of data; it only expects the data to be sequential in nature.

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Conjunction Of Factors Impacting The 2019-2020 Flu Season In The Us, Yichen Wang Apr 2021

Conjunction Of Factors Impacting The 2019-2020 Flu Season In The Us, Yichen Wang

Undergraduate Research Symposium 2021

The 2019-2020 flu season is regarded as one of the most serious ones in decades. Previous researchers usually studied the effects of different factors on seasonal flu separately instead of their conjugate impact, so we wanted to find how multiple factors combine to affect the spread of influenza in the 2019-2020 flu season in America. We chose types of virus (A and B), environmental factors (temperature, precipitation, relative humidity), population density, and influenza vaccination status for different age groups which are statewide data containing monthly information from Sep. 2019 to May 2020. By principal component analysis, we could see the …

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Anion Removal By Partially Positive Adsorbents, Breanna Dragseth, Matt Desmith, Emily Robinson, Abi Bartlett Apr 2021

Anion Removal By Partially Positive Adsorbents, Breanna Dragseth, Matt Desmith, Emily Robinson, Abi Bartlett

Undergraduate Research Symposium 2021

Nitrates and phosphates exist naturally but are present in elevated concentrations in many areas primarily due to agriculture; these elevated concentrations are concerning for human and environmental health. The project considered the ability of four different materials used for adsorption (adsorbents) to adsorb nitrate and phosphate. All adsorbents had a silica base with an amine (NH2) group and were further functionalized with different ligands consisting of an aromatic ring functionalized with electron withdrawing groups, creating a partial positive environment to help attract the anions of interest. We also synthesized control materials to determine how effective our engineered materials are. The …

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Research On Some Questions Of Simulation Body Of Knowledge, Xiaogang Qiu, Duan Hong, Xie Xu, Bin Chen Apr 2021

Research On Some Questions Of Simulation Body Of Knowledge, Xiaogang Qiu, Duan Hong, Xie Xu, Bin Chen

Journal of System Simulation

Abstract: Simulation body of knowledge (BOK) is the knowledge required to conduct Modeling and Simulation (M&S) activities, which is a logic system consisting of concepts, propositions, and inferences that are tightly related to each other. The simulation BOK organizes the M&S knowledge in a hierarchical way, reflects the composition and structure of the knowledge in the M&S domain. The establishment of the simulation BOK is crucial to advance the M&S research and education. The requirements for establishing the simulation BOK are summarized, three basic features of the simulation knowledge, practical, systematical, and epochal are discussed, the challenges of establishing the …

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Study On Composition Of Simulation Discipline Knowledge Areas, Duan Hong, Xiaogang Qiu, Xie Xu, Rusheng Ju Apr 2021

Study On Composition Of Simulation Discipline Knowledge Areas, Duan Hong, Xiaogang Qiu, Xie Xu, Rusheng Ju

Journal of System Simulation

Abstract: Many disciplines, such as Software Engineering, Automation, have sorted out and formed their own knowledge areas and constructed their Body of Knowledge to steer teaching and study efforts. Describing the composition of Modeling and Simulation body of knowledge from the perspective of knowledge area plays an important role in the simulation engineering education and the development of simulation technology. According to the needs of simulation teaching, the body of knowledge of simulation discipline is divided into three levels, knowledge area, knowledge unit and knowledge topic. On the basis of reviewing the current status of the research and the role …

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Socastee Interview, Participant #13, April 14, 2021, Jennifer Mokos, Jaime Mccauley Apr 2021

Socastee Interview, Participant #13, April 14, 2021, Jennifer Mokos, Jaime Mccauley

Flood Survivor Interviews

A community member of the Rosewood neighborhood in Socastee is interviewed by a CCU student.

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Water Quality Assessment Of Farmville, Va, Meghan Hall Apr 2021

Water Quality Assessment Of Farmville, Va, Meghan Hall

Spring Showcase for Research and Creative Inquiry

In Farmville, some people drink tap water, but others choose only to drink filtered or bottled water. Some blame this on taste, and others say the mineral content affects their skin from sinks and showers. I propose to conduct an analysis of water hardness and chloride, nitrate, and lead levels of water from various sources in Farmville, Virginia. To measure each parameter, an EDTA titration was carried out to test for water hardness, anodic stripping voltammetry was conducted to detect lead, ion-selective electrode was used to measure chloride, and a modified Griess reaction was carried out to measure nitrate levels. …

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Which Weather And Water Conditions Affect The Biodiversity And Abundance Of Macroinvertebrates The Most?, Alyssa Oppedisano, Phil Anderson, Val Phillips Apr 2021

Which Weather And Water Conditions Affect The Biodiversity And Abundance Of Macroinvertebrates The Most?, Alyssa Oppedisano, Phil Anderson, Val Phillips

Spring Showcase for Research and Creative Inquiry

Macroinvertebrates are important biological monitors that play a valuable role in the metabolism of freshwater food chains. Previous studies have suggested that conditions such as dissolved oxygen, pH, water temperature, precipitation, and air temperature can affect the abundance of macroinvertebrates which can in turn affect the health of freshwater ecosystems. This research aimed to find the relationship between macroinvertebrate biodiversity and various environmental conditions in freshwater ecosystems. Weather data was taken from a weather station at Lancer Park and water data was taken on-site at Wilson stream, both locations in Farmville, Virginia. Sample collection and identification occurred twice a week …

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Microplastics In Urban Stormwater Ponds, Maryelizabeth Crabbs, James Giering Apr 2021

Microplastics In Urban Stormwater Ponds, Maryelizabeth Crabbs, James Giering

Spring Showcase for Research and Creative Inquiry

Microplastics are pieces of plastic that have been broken down into extremely small particles. If introduced into the aquatic environment microplastics can impose adverse effects on aquatic wildlife, especially if they are ingested. The purpose of this study is to analyze the concentrations of microplastics in the waters of local stormwater ponds and compare them to a natural pond. Three ponds in the Farmville area were tested: two stormwater ponds on Longwood University's campus and one natural pond with limited human influence at an off campus location. Water samples were taken weekly over a five week period and then analyzed …

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Effect Of Lancer Park Detention Pond On Stormwater Sediment Concentrationsâ , Randolph Zerick, Rian Blakesley, Jason Seagraves, Joey Kohler Apr 2021

Effect Of Lancer Park Detention Pond On Stormwater Sediment Concentrationsâ , Randolph Zerick, Rian Blakesley, Jason Seagraves, Joey Kohler

Spring Showcase for Research and Creative Inquiry

During rain events, stormwater collects sediments and other pollutants during runoff and transports them to receiving water bodies. Detention ponds can reduce pollutant concentrations in stormwater by allowing particulate matter to settle out of the water column. The objective of this study was to determine the effectiveness of Longwood University's Lancer Park stormwater detention pond in reducing sediment concentrations. This was accomplished by quantifying the difference between sediment concentrations of stormwater entering and leaving the pond. Inflow and outflow samples were collected from the pond for 3 separate rain events and the samples were filtered, dried, and weighed. The change …

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Engineering Donor-Acceptor Conjugated Polymers For High-Performance And Fast-Response Organic Electrochemical Transistors, Hanyu Jia, Zhen Huang, Peiyun Li, Song Zhang, Yunfei Wang, Jie Yu Wang, Xiaodan Gu, Ting Lei Apr 2021

Engineering Donor-Acceptor Conjugated Polymers For High-Performance And Fast-Response Organic Electrochemical Transistors, Hanyu Jia, Zhen Huang, Peiyun Li, Song Zhang, Yunfei Wang, Jie Yu Wang, Xiaodan Gu, Ting Lei

Faculty Publications

To date, high-performance organic electrochemical transistors (OECTs) have mostly been based on polythiophene systems. Donor–acceptor (D–A) conjugated polymers are expected to be promising materials for OECTs owing to their high mobility and comparatively low crystallinity (good for ion diffusion). However, the OECT performance of D–A polymers lags far behind that of the polythiophenes. Here we synergistically engineered the backbone and side chain of a series of diketopyrrolopyrrole (DPP)-based D–A polymers and found that redox potential, molecular weight, solution processability, and film microstructures all have a severe impact on their performance. After systematic engineering, P(bgDPP-MeOT2) exhibited the best figure-of-merit (μC …

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Probing The Galactic Agb Population Through Infrared And Sio Maser Emission, Megan O. Lewis Apr 2021

Probing The Galactic Agb Population Through Infrared And Sio Maser Emission, Megan O. Lewis

Physics & Astronomy ETDs

Stars on the Asymptotic Giant Branch (AGB) are of low to intermediate mass and have reached the end stages of stellar evolution. The mass-loss that stars undergo at this phase enshrouds the central star in a circumstellar envelope (CSE) that redistributes most of the stellar light into the infrared (IR) regime of the spectrum. In the CSEs of oxygen-rich AGB stars molecules including SiO form, and under certain conditions maser emission from SiO can make AGB stars bright beacons at radio frequencies (e.g., 43 and 86 GHz). SiO masers are ideal observational probes of AGB sources, providing data on their …

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Compensation Sliding Cross Coupling Control Research Of Cartesian Coordinate Robot, Wang Wei, Zhimei Chen, Zhenyan Wang Apr 2021

Compensation Sliding Cross Coupling Control Research Of Cartesian Coordinate Robot, Wang Wei, Zhimei Chen, Zhenyan Wang

Journal of System Simulation

Abstract: For a typical Cartesian coordinate robot controls precision is low, based on a single-axis mathematical model, a contour error model for a typical robot whose axes are orthogonal to each other is established. An improved double-power approach law is used to design a terminal sliding mode controller to improve the robot. The integral compensation terms are added to stably compensate the position accuracy of each axis to improve the overall trajectory tracking accuracy, and the cross-coupling control between the axes is used to eliminate the contour error between the axes. It not only weakens the chattering of traditional sliding …

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Design And Implementation Of Multi Level Terrain Editing Tool, Xiang Bing, Yang Gang, Xiaohong Dong Apr 2021

Design And Implementation Of Multi Level Terrain Editing Tool, Xiang Bing, Yang Gang, Xiaohong Dong

Journal of System Simulation

Abstract: 3D terrain is an indispensable scene element in computer games, virtual simulation, geographic information and other applications. Realistic digital terrain plays an important role in enhancing the reality of virtual scene and the immersion of users. Based on the in-depth analysis of terrain features and user modeling requirements, a multi-level terrain editing mode is constructed. In the mode, the terrain editing behavior can be expanded from three levels of point, line and face. Each level has a specific operation target and corresponding editing tools. A multi-level and comprehensive terrain editing tool set composed of point tool, curve tool and …

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Cis-Trans Isomerism In Single Molecule Electronic Devices, Tinsae Alem Apr 2021

Cis-Trans Isomerism In Single Molecule Electronic Devices, Tinsae Alem

Spring Showcase for Research and Creative Inquiry

We investigated the switching properties of cis-trans isomers of azobenzene for single molecule electronics. Although the cis-trans isomerization leads to structural changes within the molecule, the current flow is found to depend mainly on the relative position of the electrodes. The on/off ratio was determined to measure the performance of these isomers as switches. Different cis-trans isomers were studied to compare results.

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In Silico Screeing Of Natural Compounds As Novel Drug Targets For Treatment Of Multiple Myeloma, Rousselene Larson Apr 2021

In Silico Screeing Of Natural Compounds As Novel Drug Targets For Treatment Of Multiple Myeloma, Rousselene Larson

Student Research Symposium

In Silico Screening of Natural Compounds as Novel Drug Targets for The Treatment of Multiple MyelomaRousselene Larson1 2, Naveen Duhan1, and Rakesh Kaundal1 2 *1Department of Plants, Soils, and Climate, College of Agriculture and Applied Sciences; 2Bioinformatics Facility, Center for Integrated BioSystems; Utah State University, Logan, UT 84322 USA* corresponding author (e-mail: rkaundal@usu.edu)Telephone: +1 (435) 797-4117Fax: +1 (435) 797-2766Abstract: Multiple Myeloma (MM) is an incurable hematological malignancy cancer characterized by excessive clonal plasma cell proliferation in the bone marrow. In the United States, MM is the second most prevalent type of cancer that affects about 4 in 100,000 Americans. Toxicity …

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Small Fault Detection Based On Cumulative Sum Of Neighbor Statistic, Xiaoping Guo, Jiajun Gao, Jianbin Guo, Li Yuan Apr 2021

Small Fault Detection Based On Cumulative Sum Of Neighbor Statistic, Xiaoping Guo, Jiajun Gao, Jianbin Guo, Li Yuan

Journal of System Simulation

Abstract: Aiming at the small faults and the common data non-linear problems of industrial process, a fault detection method based oncumulative sum of neighbor statistic (CUSUM-NS) is proposed. Mutual information principal component analysis (MIPCA) is used to reduce the dimension of training data, and the principal components based on mutual information are extracted to construct a new sample space. For the new sample space after dimensionality reduction, the nonlinear features of the process data can be fully extracted through the distance square sum statistics of k nearest neighbors. Cumulative summation(CUSUM) method is used to accumulate the sum of squares of …

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Mesh Solid Construction Algorithm Of Spiral Bevel Gear Based On Virtual Collision Body, Cheng'en Li, Xiangjun Zou, Zeqin Zeng, Jianhua He, Li Hui, Zhaofeng Huang Apr 2021

Mesh Solid Construction Algorithm Of Spiral Bevel Gear Based On Virtual Collision Body, Cheng'en Li, Xiangjun Zou, Zeqin Zeng, Jianhua He, Li Hui, Zhaofeng Huang

Journal of System Simulation

Abstract: In order to improve the production automation, intelligence level and production efficiency of the tractor rear axle, the spiral bevel gear mesh entity based on the virtual collision body is constructed to carry out the human-machine interaction virtual simulation experiment of the tractor rear axle. The spiral bevel gear made by Gleason as is taken an example, the processing technology of arc spur gear is analyzed, the kinematics is used to establish a mathematical model of the spiral bevel gear forming process. The differential and interpolation methods are used to fit the gear curve and surface, the contour point …

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Gas-Liquid Two-Phase Flow Pattern Recognition Method Based On Convolutional Neural Network, Weiguo Tong, Xuechun Pang, Genghong Zhu Apr 2021

Gas-Liquid Two-Phase Flow Pattern Recognition Method Based On Convolutional Neural Network, Weiguo Tong, Xuechun Pang, Genghong Zhu

Journal of System Simulation

Abstract: Aiming at the low recognition rate and subjectivity in two-phase flow pattern recognition, a method based on Landweber iterative image reconstruction algorithm and convolutional neural network is proposed. Landweber iterative image reconstruction algorithm is used to obtain the flow pattern images and build the flow pattern image database. By means of the flow pattern identification on, different convolution layers in VGG16 network and different size and resolution of the data set samples, the parameters of network frozen convolutional layer and input image are determined.The experimental results show that the combined method of resistance tomography and convolutional neural network …

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Design And Electromagnetic Simulation Of Split Switched Reluctance Dual-Rotor Motor, Deng Tao, Deng Song Apr 2021

Design And Electromagnetic Simulation Of Split Switched Reluctance Dual-Rotor Motor, Deng Tao, Deng Song

Journal of System Simulation

Abstract: There are some problems such as bad heat dissipation and electromagnetic coupling for the traditional dual-rotor motor of hybrid electric vehicles. Two SRMs of same size are mechanically connected through a coupling to form a dual-rotor motor with two rotors and one stator. A split switched reluctance dual-rotor motor (SSR-DRM) is innovatively designed. The working principle and multi-operating mode of SSR-DRM are analyzed, and the parameters design, modeling and electromagnetic simulation are implemented. The parameters of design and simulation are compared and analyzed from the aspects of magnetic line distribution, magnetic density, transient torque and no-load back …

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Modeling And Verification Of Scene Of C3+Ato System Based On Timed Automata, Zhenhai Zhang, Yao Jie Apr 2021

Modeling And Verification Of Scene Of C3+Ato System Based On Timed Automata, Zhenhai Zhang, Yao Jie

Journal of System Simulation

Abstract: The C3+ATO system is in the experimental stage in our country and has the characteristics of high automation degree and high safety requirement at present. In order to confirm whether the specific function of the high-speed railway C3+ATO system meets the corresponding technical specification under the specific scene, a formal modeling and verification method based on the timed automata is proposed. The station automatic departure scene is selected as the modeling object. The functional requirements of C3+ATO system specification are extracted and the timed automata model of the scene is established. The message sequence chart of the corresponding process …

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Operation Resilience Optimization Of Power System Considering Generalized Energy Storage, Weiqing Sun, Zhang Jie, Ye Lei, Han Dong Apr 2021

Operation Resilience Optimization Of Power System Considering Generalized Energy Storage, Weiqing Sun, Zhang Jie, Ye Lei, Han Dong

Journal of System Simulation

Abstract: Based on the definition and principle of power system resilience, combining the traditional energy storage equipment with the demand response, an optimization method of power system operation resilience considering generalized energy storage is proposed. Five attack schemes based on topology are evaluated according to four indexes, and the most disadvantageous attack strategy is selected to simulate the damage of power system. Taking the minimum operating cost of the system as the objective, a combined scheduling model involving wind power station and energy storage unit is carried out. A generalized energy storage scheduling method is proposed to improve the …

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Effect Of Lancer Park Detention Pond On Stormwater Sediment Concentrations, Rian Blakesley, Randolph Zerick, Jason Seagraves, Joseph Kohler Apr 2021

Effect Of Lancer Park Detention Pond On Stormwater Sediment Concentrations, Rian Blakesley, Randolph Zerick, Jason Seagraves, Joseph Kohler

Spring Showcase for Research and Creative Inquiry

During rain events, stormwater collects sediments and other pollutants during runoff and transports them to receiving water bodies. Detention ponds can reduce pollutant concentrations in stormwater by allowing particulate matter to settle out of the water column. The objective of this study was to determine the effectiveness of Longwood University's Lancer Park stormwater detention pond in reducing sediment concentrations. This was accomplished by quantifying the difference between sediment concentrations of stormwater entering and leaving the pond. Inflow and outflow samples were collected from the pond for 3 separate rain events and the samples were filtered, dried, and weighed. The change …

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