scholarly journals The impact of stitched hybrid systems in hybrid bermudagrass athletic fields

itsrj ◽  
2021 ◽  
Author(s):  
K. H. Dickson ◽  
J. C. Sorochan ◽  
W.D. Strunk
Keyword(s):  
Hybrid Systems ◽  
Athletic Fields ◽  
The Impact

scholarly journals A Real-Time Degradation Model for Hardware in the Loop Simulation of Fuel Cell Gas Turbine Hybrid Systems

2015 ◽  
Author(s):  
Valentina Zaccaria ◽  
Alberto Traverso ◽  
David Tucker
Keyword(s):  
Fuel Cell ◽  
Real Time ◽  
Gas Turbine ◽  
Hybrid Systems ◽  
Current Density ◽  
Gas Turbines ◽  
Hardware In The Loop ◽  
Fuel Utilization ◽  
Time Operation ◽  
The Impact

The theoretical efficiencies of gas turbine fuel cell hybrid systems make them an ideal technology for the future. Hybrid systems focus on maximizing the utilization of existing energy technologies by combining them. However, one pervasive limitation that prevents the commercialization of such systems is the relatively short lifetime of fuel cells, which is due in part to several degradation mechanisms. In order to improve the lifetime of hybrid systems and to examine long-term stability, a study was conducted to analyze the effects of electrochemical degradation in a solid oxide fuel cell (SOFC) model. The SOFC model was developed for hardware-in-the-loop simulation with the constraint of real-time operation for coupling with turbomachinery and other system components. To minimize the computational burden, algebraic functions were fit to empirical relationships between degradation and key process variables: current density, fuel utilization, and temperature. Previous simulations showed that the coupling of gas turbines and SOFCs could reduce the impact of degradation as a result of lower fuel utilization and more flexible current demands. To improve the analytical capability of the model, degradation was incorporated on a distributed basis to identify localized effects and more accurately assess potential failure mechanisms. For syngas fueled systems, the results showed that current density shifted to underutilized sections of the fuel cell as degradation progressed. Over-all, the time to failure was increased, but the temperature difference along cell was increased to unacceptable levels, which could not be determined from the previous approach.

scholarly journals Fluid limit theorems for stochastic hybrid systems with application to neuron models

2010 ◽  
Vol 42 (3) ◽  
pp. 761-794 ◽  
Author(s):  
K. Pakdaman ◽  
M. Thieullen ◽  
G. Wainrib
Keyword(s):  
Hybrid Systems ◽  
Central Limit ◽  
Markov Processes ◽  
Limit Theorems ◽  
Channel Noise ◽  
Stochastic Hybrid Systems ◽  
Neuron Models ◽  
Fluid Limit ◽  
The Impact ◽  
Jump Markov Processes

In this paper we establish limit theorems for a class of stochastic hybrid systems (continuous deterministic dynamics coupled with jump Markov processes) in the fluid limit (small jumps at high frequency), thus extending known results for jump Markov processes. We prove a functional law of large numbers with exponential convergence speed, derive a diffusion approximation, and establish a functional central limit theorem. We apply these results to neuron models with stochastic ion channels, as the number of channels goes to infinity, estimating the convergence to the deterministic model. In terms of neural coding, we apply our central limit theorems to numerically estimate the impact of channel noise both on frequency and spike timing coding.

Optimal location and sizing of small hybrid systems in micro-grid system using Volunteer Geographic Information

2020 ◽  
Author(s):  
Javier Valdes ◽  
Sebastian Wöllmann ◽  
Roland Zink
Keyword(s):  
Simulation Model ◽  
Hybrid Systems ◽  
Optimization Model ◽  
Geographic Information ◽  
Optimal Location ◽  
Grid System ◽  
Volunteer Geographic Information ◽  
Micro Grid ◽  
The Impact ◽  
Micro Grids

<p><strong>Optimal location and sizing of small hybrid systems in micro-grid system using Volunteer Geographic Information</strong></p><p> </p><p>This study presents an optimization model for the optimal location and sizing of small hybrid systems in simulated micro-grids. By using an optimization model - in combination with COSMO-REA2 weather data - various micro-grids local energy systems are simulated using the Calliope energy simulation model. The Calliope optimization and simulation model is feed with GIS-data from different Volunteered Geographic Information projects, including OpenStreetMap. These allows to automatically allocate specific demand profiles to diverse OpenStreetMap building categories. Moreover, based on the characteristics of the OpenStreetMap data, a set of possible distributed energy resources) including renewables and fossil fueled generators are defined for each building category. The optimization model is applied for a set of scenarios based on different electricity prices and technological characteristics. This allows to assess the impact and profitability of the different technological options on the micro-grid configuration. Moreover, in order to assess the impact of each of the scenarios on the current distribution infrastructure, the results of the simulations are included on an existing model of the low and middle voltage network for Lower Bavaria, Germany. Finally, to facilitate their dissemination, the results of the simulation are stored in a PostgreSQL database, before they are delivered by a RESTful Laravel Server and displayed in an Angular Web-Application.</p>

scholarly journals Review of Impedance-Based Analysis Methods Applied to Grid-Forming Inverters in Inverter-Dominated Grids

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2686
Author(s):  
Ishita Ray
Keyword(s):  
State Space ◽  
Power Electronics ◽  
Hybrid Systems ◽  
Distributed Generation ◽  
Droop Control ◽  
Output Stability ◽  
Input And Output ◽  
Analysis Methods ◽  
The Stability ◽  
The Impact

As the use of distributed generation with power electronics-based interfaces increases, the separation between DC and AC parts of the grid is reduced. In such inverter-dominated AC grids, impedance-based analysis methods are proving to be more powerful than traditional state-space-based analysis methods. Even the conventional parameters and standards used to estimate the stability of generators and stronger grids cannot fully capture the dynamics of weaker, inverter-dominated grids. It then stands to reason that system impedances that are commonly used to analyze DC systems will be useful in the analysis of grid-forming inverters in these hybrid systems. To understand the value of studying the impedances of inverters and other elements in weak AC grids, this article reviews and describes the various ways in which impedance-based analyses can be used to define, assess, and improve the performance of grid-forming inverter controllers. An exemplary case using the conventional P-f/Q-V droop control demonstrates the application of impedance-based analyses to determine the impact of the controller on the input and output stability of the inverter.

The impact of water on photopolymerization kinetics of methacrylate/vinyl ether hybrid systems

2005 ◽  
Vol 16 (2-3) ◽  
pp. 195-199 ◽  
Author(s):  
Yan Lin ◽  
Jeffrey W. Stansbury
Keyword(s):  
Hybrid Systems ◽  
Vinyl Ether ◽  
The Impact ◽  
Kinetics Of ◽  
Photopolymerization Kinetics

Turbocharger-Based Hybrid Systems: Modeling and Validation of a Free Spool Subject to Compressor Surge

2018 ◽  
Author(s):  
Alessio Abrassi ◽  
Alberto Traverso ◽  
Lorenzo Ferrari
Keyword(s):  
Fuel Cell ◽  
Hybrid Systems ◽  
Software Tool ◽  
Calculation Model ◽  
Operating Conditions ◽  
System Response ◽  
Dynamic Approach ◽  
Compressor Surge ◽  
Pressure Changes ◽  
The Impact

Compressor surge is one of the main problem that may affect fuel cell gas turbine hybrid systems, because of the energy stored in the volume containing the high temperature pressurized fuel cell stack. The problem becomes even more crucial because in such kind of system, the fuel cell is the most sensitive and costly component that has to be preserved by abrupt pressure changes. In order to determine the behavior of a dynamic compressor in its whole range of operating conditions, a calculation model was implemented in TRANSEO, a software tool for transient and dynamic analysis of microturbine and fuel cell based-cycles (based on Matlab-Simulink environment). The modeling procedure has been derived from the Greitzer’s 1976 nonlinear dynamic approach; the resulting T-RIG1 model predicts the transient response of a compression system and is able to simulate both normal and instable transient conditions. Several investigations have been done in order to characterize the impact of different parameters and configurations on the system response. The validation, in the frequency domain, was performed comparing calculations with experimental data measured from a dedicated test rig, where a small size turbocharger has been operated in stable and unstable conditions. In particular, the present work demonstrates the capability of the T-RIG1 model to simulate a free shaft turbocharger performance and instability, with the future purpose to develop feasible strategies for surge detection and recovery, applicable to turbocharger-based hybrid systems.

scholarly journals Fluid limit theorems for stochastic hybrid systems with application to neuron models

2010 ◽  
Vol 42 (03) ◽  
pp. 761-794 ◽  
Author(s):  
K. Pakdaman ◽  
M. Thieullen ◽  
G. Wainrib
Keyword(s):  
Hybrid Systems ◽  
Central Limit ◽  
Markov Processes ◽  
Limit Theorems ◽  
Channel Noise ◽  
Stochastic Hybrid Systems ◽  
Neuron Models ◽  
Fluid Limit ◽  
The Impact ◽  
Jump Markov Processes

In this paper we establish limit theorems for a class of stochastic hybrid systems (continuous deterministic dynamics coupled with jump Markov processes) in the fluid limit (small jumps at high frequency), thus extending known results for jump Markov processes. We prove a functional law of large numbers with exponential convergence speed, derive a diffusion approximation, and establish a functional central limit theorem. We apply these results to neuron models with stochastic ion channels, as the number of channels goes to infinity, estimating the convergence to the deterministic model. In terms of neural coding, we apply our central limit theorems to numerically estimate the impact of channel noise both on frequency and spike timing coding.

scholarly journals Factors Affecting School Grounds and Athletic Field Quality after Pesticide Bans: The Case of Connecticut

HortScience ◽  
2015 ◽  
Vol 50 (1) ◽  
pp. 99-103 ◽  
Author(s):  
Candace Bartholomew ◽  
Benjamin L. Campbell ◽  
Victoria Wallace
Keyword(s):  
United States ◽  
Pest Management ◽  
The United States ◽  
Lower Income ◽  
Factors Affecting ◽  
Lawn Care ◽  
Field Quality ◽  
Athletic Fields ◽  
Athletic Field ◽  
The Impact

Pesticide laws focused on school grounds/athletic fields are beginning to take shape around the United States. A body of literature has examined the health implications of pesticides on school children and faculty and staff. However, little research has examined the impact of changing pesticide regulations on grounds/field quality and expenses. Our research indicate that school grounds/field managers have perceived decreased quality after the Connecticut kindergarten to eighth grade pesticide ban went into effect in 2010. Furthermore, we find that educational sessions or increased expenditures on school grounds/fields can increase the probability of maintaining field quality at integrated pest management levels. However, we see that lower income areas are more likely to experience decreased grounds/field quality after the lawn care pesticide ban took effect.

Impact of third generation synthetic turf athletic field age on surface hardness and infill depth spatial variability

2021 ◽  
pp. 175433712110029
Author(s):  
Kyley H Dickson ◽  
Chase M Straw ◽  
Adam W Thoms ◽  
Troy D Carson ◽  
John C Sorochan
Keyword(s):  
Spatial Variability ◽  
National Football League ◽  
Fiber Type ◽  
Negative Relationship ◽  
Surface Hardness ◽  
Third Generation ◽  
Athletic Fields ◽  
The Impact ◽  
Over Time ◽  
Synthetic Turf

The use of synthetic turf (ST) has become a popular option for many athletic fields. Little is known about how surface hardness and infill depth spatial variability changes over time on third generation (3G) ST athletic fields. A research study was conducted to investigate the impact of field age on surface hardness and infill depth spatial variability from 12 3G ST athletic fields in Tennessee and Georgia (USA) between March 5, 2014 and April 8, 2014. The 3G ST athletic fields tested varied in fiber type including monofilament, slit film, and a combination of monofilament with slit film fibers. All 3G ST athletic fields were directly over gravel with no shockpad present. Surface hardness and infill depth were collected in the same location on all fields. Surface hardness was collected with the Toro Mobile Tester (400–450 samples/field) and infill depth was collected manually with a three-prong infill depth gauge (200–225 samples/field). As field age increased, surface hardness and spatial variability of the surface hardness increased significantly. Surface hardness and infill depth also had a significant negative relationship with one another. The increase in mean surface hardness and variability is partially attributed to infill depth loss and compaction of the remaining infill. Infill depth did not have a significant relationship with age, unless plots were outside the manufacturer’s recommendation for infill depth. Considering the nearly 3000 samples collected in this study, maintaining a minimum infill depth between 30 and 35 mm kept 90% of surface hardness data points below the National Football League limit of 100 Gmax. Results from this study highlight how 3G ST athletic fields can change with age, which may indicate the need for targeted infill applications and decompaction to improve field uniformity over time.

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