Atmospheric stability determination using fine time-step intervals for timing of aerial application

2016 ◽  
Keyword(s):  
Atmospheric Stability ◽  
Aerial Application ◽  
Time Step ◽  
Fine Time

scholarly journals The Advanced Multilevel Predictor-Corrector Quasi-Static Method for Pin-Resolved Neutron Kinetics Simulation

2021 ◽  
Vol 9 ◽  
Author(s):  
Le Kang ◽  
Chen Hao ◽  
Qiang Zhao ◽  
Yunlin Xu
Keyword(s):  
Static Method ◽  
Time Step ◽  
Control Rod ◽  
Dynamic Iteration ◽  
Kinetics Simulation ◽  
Coupling Algorithm ◽  
Predictor Corrector ◽  
Point Kinetics ◽  
Fine Time ◽  
Exact Point

The Advanced Multilevel Predictor-Corrector Quasi-static Method (AML-PCQM) is proposed in this work. The four computational levels, including transport, Multi-Group (MG) Coarse Mesh Finite Difference (CMFD), One-Group (1G) CMFD, and Exact Point-Kinetics Equation (EPKE), are coupled with a new dynamic iteration strategy. In each coupling algorithm, the original Transient Fixed Source Problem (TFSP) is solved in the predictor process using coarse time step, and then the flux distribution is factorized to the functions of amplitude and shape in the next corrector process. Finally, multiple fine time steps are used to adjust the predicted solution. Two heterogeneous single assembly problems with the prompt control rod withdrawal event are used to verify the AML-PCQM scheme’s accuracy and efficiency. The numerical results obtained by different cases are compared and analyzed. The final results indicate that the AML-PCQM performs the remarkable advantages of efficiency and accuracy with the reference cases.

A Real-time Web Tool for Safe Aerial Application to Avoid Off-target Movement of Spray Induced by Stable Atmospheric Conditions in the Mississippi Delta

2019 ◽  
Vol 35 (1) ◽  
pp. 31-38
Author(s):  
Yanbo Huang ◽  
Daniel K Fisher ◽  
Mark Silva ◽  
Steven J Thomson
Keyword(s):  
Real Time ◽  
Web Application ◽  
Mississippi Delta ◽  
Crop Protection ◽  
Atmospheric Stability ◽  
Temperature Inversion ◽  
Crop Damage ◽  
Atmospheric Conditions ◽  
Aerial Application ◽  
Target Movement

Abstract. Susceptible crops can be injured far downwind if proper application spray procedure is not followed. Avoidance of stable atmospheric conditions while spraying is important to prevent surface temperature inversion-induced off-target drift of crop protection materials. Our previous studies consistently indicated high likelihood (>90%) of stable atmospheric conditions (unfavorable for spraying) primarily between the hours of 6:00 pm and 6:00 am during clear conditions in the hot summer months at the Mississippi Delta. With the requirement of timely farm operations, a web application has been developed to provide real-time determination of atmospheric stability and to recommend whether aerial applications are appropriate for a particular location and time. An algorithm was developed to determine atmospheric conditions likely for occurrence of a temperature inversion. This algorithm was programmed using the Python programming language and uploaded to an internet-cloud application platform for publication via HTML. The algorithm calculates the potential of a temperature inversion every hour based on air temperature and wind speed data measured at weather stations deployed over the Mississippi Delta and surrounding areas. The web application is adapted for mobile terminals, such as smartphones and tablets, and can provide timely guidance for aerial applicators and producers to avoid crop damage and air quality issues long distances downwind. Keywords: Aerial application, Spray drift, Temperature inversion, Atmospheric stability, Crop protection, Web application, Mobile terminal.

scholarly journals Impact Analysis of Environmental Conditions on Odour Dispersion Emitted from Pig House with Complex Terrain Using CFD

Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1828
Author(s):  
Uk-Hyeon Yeo ◽  
Cristina Decano-Valentin ◽  
Taehwan Ha ◽  
In-Bok Lee ◽  
Rack-Woo Kim ◽  
...  
Keyword(s):  
Wind Speed ◽  
Complex Terrain ◽  
Impact Analysis ◽  
Atmospheric Stability ◽  
Influential Factor ◽  
Cfd Model ◽  
Time Step ◽  
Key Factor ◽  
Computational Fluid Dynamics Cfd ◽  
Odour Dispersion

With the rise in livestock production, the odour concentration emitted from livestock facilities has significantly increased. For this reason, odour complaints have become a major issue. The dispersion of the odour into the atmosphere is affected by various factors (wind speed, wind direction, atmospheric stability, terrain condition, ventilation type, and so on). Thus, a thorough analysis on the factor influencing odour dispersion is necessary to establish regulations and policies for odour management. Therefore, this research aimed to evaluate odour dispersion generated from a pig house with complex terrain using computational fluid dynamics (CFD) and to statistically determine the key factor for odour dispersion. By comparing CFD-computed results with field-measured data, an appropriate grid size, time step, and turbulence model of the CFD model were determined. Considering various factors, case studies were performed using the validated CFD model. The CFD-computed results showed that odour dispersion distance at the level of 1 OU m−3 ranged from 129.7 to 1488.1 m. The prediction of odour dispersion distance varies with the change of factor being analysed. Finally, the statistical analysis showed that the most influential factor that affected odour dispersion distance was the wind speed with a t-value: −9.057.

Swim speeds and energy use of upriver-migrating sockeye salmon (Oncorhynchus nerka): simulating metabolic power and assessing risk of energy depletion

1998 ◽  
Vol 55 (8) ◽  
pp. 1832-1841 ◽  
Author(s):  
Peter S Rand ◽  
Scott G Hinch
Keyword(s):  
Power Consumption ◽  
Time Scale ◽  
Sockeye Salmon ◽  
Energy Use ◽  
Oncorhynchus Nerka ◽  
Fraser River ◽  
Metabolic Power ◽  
Time Step ◽  
Fine Time ◽  
Daily Time

We simulated metabolic power consumed by Fraser River sockeye salmon (Oncorhynchus nerka) during upriver migration based on direct measures of activity from physiological field telemetry. The most accurate prediction of energy expenditure was obtained by expressing activity as a fine time scale (5 s) stochastic process. By imposing a daily time step, predictions of energy use were considerably lower than observed energy use, suggesting that the practice of modeling field energetics at a daily time scale, particularly for relatively active fish, may render dubious results. Daily mean power consumption through the Fraser River Canyon by the average migrant was about 20 W, about fourfold higher than for less constricted reaches. Power consumption predicted at fine time scales ranged from <1 W (0.1 body length·s-1) during periods of reduced activity to 1700 W (8 body lengths·s-1) during bursts while navigating through turbulent canyon reaches. Through Monte Carlo simulations representing environmental variability observed during 1950-1994, we determined that 8% of the salmon runs during this time resulted in high risk of exhaustion for the average migrant that could lead to elevated in-river mortality. Reducing harvest levels on sockeye salmon that may be exposed to these unfavourable conditions may assist agencies in achieving a risk-averse management strategy.

Toward a neuroscope: An application of high-performance computing for real-time evaluation of brain function using MRI

1994 ◽  
Vol 52 ◽  
pp. 922-923
Author(s):  
C. S. Potter ◽  
C. D. Gregory ◽  
H. D. Morris ◽  
Z.-P. Liang ◽  
P. C. Lauterbur
Keyword(s):  
Human Brain ◽  
Brain Function ◽  
High Performance ◽  
Complex Signal ◽  
Time Step ◽  
Brain Organization ◽  
Cognitive Studies ◽  
Positron Emission ◽  
Imaging And Spectroscopy ◽  
3D Anatomy

Over the past few years, several laboratories have demonstrated that changes in local neuronal activity associated with human brain function can be detected by magnetic resonance imaging and spectroscopy. Using these methods, the effects of sensory and motor stimulation have been observed and cognitive studies have begun. These new methods promise to make possible even more rapid and extensive studies of brain organization and responses than those now in use, such as positron emission tomography.Human brain studies are enormously complex. Signal changes on the order of a few percent must be detected against the background of the complex 3D anatomy of the human brain. Today, most functional MR experiments are performed using several 2D slice images acquired at each time step or stimulation condition of the experimental protocol. It is generally believed that true 3D experiments must be performed for many cognitive experiments. To provide adequate resolution, this requires that data must be acquired faster and/or more efficiently to support 3D functional analysis.

Efficient Treatment of Fixed and Induced Dipolar Interactions

2000 ◽  
Vol 653 ◽  
Author(s):  
Celeste Sagui ◽  
Thoma Darden
Keyword(s):  
Molecular Dynamics ◽  
Md Simulations ◽  
Lagrangian Formalism ◽  
Dipolar Interactions ◽  
Time Step ◽  
Efficient Treatment ◽  
Particle Mesh Ewald ◽  
Fixed Charges ◽  
Self Consistency ◽  
Induced Dipoles

AbstractFixed and induced point dipoles have been implemented in the Ewald and Particle-Mesh Ewald (PME) formalisms. During molecular dynamics (MD) the induced dipoles can be propagated along with the atomic positions either by interation to self-consistency at each time step, or by a Car-Parrinello (CP) technique using an extended Lagrangian formalism. The use of PME for electrostatics of fixed charges and induced dipoles together with a CP treatment of dipole propagation in MD simulations leads to a cost overhead of only 33% above that of MD simulations using standard PME with fixed charges, allowing the study of polarizability in largemacromolecular systems.

COMPARISON OF DROP SIZE DATA FROM GROUND AND AERIAL APPLICATION NOZZLES AT THREE TESTING LABORATORIES

2014 ◽  
Vol 24 (2) ◽  
pp. 181-192 ◽  
Author(s):  
Bradley K. Fritz ◽  
W. Clint Hoffmann ◽  
Greg R. Kruger ◽  
Ryan S. Henry ◽  
Andrew Hewitt ◽  
...  
Keyword(s):  
Drop Size ◽  
Aerial Application ◽  
Testing Laboratories ◽  
Size Data

Teaching AI Agents Ethical Values Using Reinforcement Learning and Policy Orchestration

2019 ◽  
Author(s):  
Ritesh Noothigattu ◽  
Djallel Bouneffouf ◽  
Nicholas Mattei ◽  
Rachita Chandra ◽  
Piyush Madan ◽  
...  
Keyword(s):  
Reinforcement Learning ◽  
Ethical Values ◽  
Large Role ◽  
Learning To Learn ◽  
Inverse Reinforcement Learning ◽  
Time Step ◽  
Novel Approach

Autonomous cyber-physical agents play an increasingly large role in our lives. To ensure that they behave in ways aligned with the values of society, we must develop techniques that allow these agents to not only maximize their reward in an environment, but also to learn and follow the implicit constraints of society. We detail a novel approach that uses inverse reinforcement learning to learn a set of unspecified constraints from demonstrations and reinforcement learning to learn to maximize environmental rewards. A contextual bandit-based orchestrator then picks between the two policies: constraint-based and environment reward-based. The contextual bandit orchestrator allows the agent to mix policies in novel ways, taking the best actions from either a reward-maximizing or constrained policy. In addition, the orchestrator is transparent on which policy is being employed at each time step. We test our algorithms using Pac-Man and show that the agent is able to learn to act optimally, act within the demonstrated constraints, and mix these two functions in complex ways.

ASSESSMENT OF MAXIMUM INSTANT DISCHARGE OF VARIOUS FREQUENCY AT UNGAUGED MOUNTAINOUS RIVER KHEMCHIK (TUVA REPUBLIC) BASED ON MATHEMATICAL MODELLING

2019 ◽  
Vol 13 (2) ◽  
pp. 36-51 ◽  
Author(s):  
O. M. Makarieva ◽  
N. V. Nesterova ◽  
G. P. Yampolsky ◽  
E. Y. Kudymova
Keyword(s):  
Coniferous Forest ◽  
Frequency Interval ◽  
Time Step ◽  
Model Calculations ◽  
Runoff Formation ◽  
Emergency Situations ◽  
Daily Streamflow ◽  
Standard Methodology ◽  
Maximum Elevation ◽  
Daily Time Step

Abstract: the article presents the results of application of distributed deterministic hydrological model Hydrograph for estimation of maximum discharge values of different frequency at the ungauged catchment of the Khemchik River (Khemchik village, Tuva Republic). The catchment area is 1750 km2 , the average and maximum elevation — 2200 and 3600 m, respectively. Due to the lack of detailed information, a schematization of the catchment and the parameterization of the model are proposed, based on general ideas about the water balance and the processes of runoff formation of the main landscapes — rocky talus, coniferous forest and steppe. Parameters and algorithms are verified based on the results of streamflow modeling at two studied catchments: the Tapsy River — Kara-Khol (302 km2 ) and the Khemchik River — Iyme (25500 km2 ). Modelling of runoff formation processes with daily time step for the Khemchik River — Khemchik village was conducted for the period 1966–2012 using observational data at Teeli meteorological station. For the transition from daily to instant discharges, the dependence of the observed values of instant and daily streamflow at the studied gauges has been applied. On the basis of simulated discharge series, the frequency curve was built and the obtained curve was compared with the calculation data according to the standard methodology SP 33-101-2003 “Determination of the main calculated hydrological characteristics” using the analogue river. Simulated maximum instant discharges for entire frequency interval of up to 1% are 1.3–5 times higher than the values obtained by standard methodology SP 33-101-2003. The results of model calculations is indirectly confirmed by the evidences of regular flooding of the Khemchik village provided by the Ministry of Emergency Situations of the Tuva Republic, which is not predicted by the values obtained by the standard methods.

Sign in / Sign up

Export Citation Format

Share Document