Theoretical evaluation of chemical and physical feasibility of an in situ ultrasonic reactor for remediation of groundwater contaminated with per‐ and polyfluoroalkyl substances

2020 ◽  
Vol 31 (1) ◽  
pp. 45-58
Author(s):  
Fiona Laramay ◽  
Michelle Crimi
Keyword(s):  
Theoretical Evaluation ◽  
Polyfluoroalkyl Substances

In Situ Experimental Validation of therm Finite Element Analysis for a High R-Value Wall Using Vacuum Insulation Panels

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Matthew J. Schiedel ◽  
Cynthia A. Cruickshank ◽  
Christopher M. Baldwin
Keyword(s):  
Finite Element ◽  
Thermal Resistance ◽  
Experimental Validation ◽  
Department Of Energy ◽  
Test Facility ◽  
Element Analysis ◽  
Theoretical Evaluation ◽  
Vacuum Insulation ◽  
R Value

This paper details the method used for a theoretical evaluation of Team Ontario's, U.S. Department of Energy Solar Decathlon 2013 entrant, high R-value wall using vacuum insulation panels (VIPs). The purpose is to determine a theoretical whole-wall thermal resistance to be used for energy modeling. Theoretical simulations are performed in therm, a two-dimensional finite element heat transfer modeling program, and an in situ experimental validation is conducted in Carleton University's Vacuum Insulation Test Facility located in Ottawa, Ontario, Canada. The theoretical model is refined based on the experimental study, and a whole-wall thermal resistance of Team Ontario's wall design is determined to be 9.4 m2·K/W (53 h·ft2·°F/Btu) at an exterior design temperature of −18 °C (0 °F).

Theoretical evaluation on laser cooling of ZBLAN:Er3+ glass with in situ optical temperature sensing

2015 ◽  
Vol 220 ◽  
pp. 362-368 ◽  
Author(s):  
Guozhu Sui ◽  
Xiangping Li ◽  
Lihong Cheng ◽  
Jiashi Sun ◽  
Jinsu Zhang ◽  
...  
Keyword(s):  
Laser Cooling ◽  
Temperature Sensing ◽  
Theoretical Evaluation

scholarly journals Bioacoustics for in situ validation of species distribution modelling: An example with bats in Brazil

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0248797
Author(s):  
Frederico Hintze ◽  
Ricardo B. Machado ◽  
Enrico Bernard
Keyword(s):  
Species Distribution ◽  
Large Scale ◽  
Species Distribution Modelling ◽  
Evaluation Metrics ◽  
Sampling Effort ◽  
International Treaties ◽  
Theoretical Evaluation ◽  
Distribution Modelling ◽  
Independent Field

Species distribution modelling (SDM) gained importance on biodiversity distribution and conservation studies worldwide, including prioritizing areas for public policies and international treaties. Useful for large-scale approaches and species distribution estimates, it is a plus considering that a minor fraction of the planet is adequately sampled. However, minimizing errors is challenging, but essential, considering the uses and consequences of such models. In situ validation of the SDM outputs should be a key-step—in some cases, urgent. Bioacoustics can be used to validate and refine those outputs, especially if the focal species’ vocalizations are conspicuous and species-specific. This is the case of echolocating bats. Here, we used extensive acoustic monitoring (>120 validation points over an area of >758,000 km2, and producing >300,000 sound files) to validate MaxEnt outputs for six neotropical bat species in a poorly-sampled region of Brazil. Based on in situ validation, we evaluated four threshold-dependent theoretical evaluation metrics’ ability in predicting models’ performance. We also assessed the performance of three widely used thresholds to convert continuous SDMs into presence/absence maps. We demonstrated that MaxEnt produces very different outputs, requiring a careful choice on thresholds and modeling parameters. Although all theoretical evaluation metrics studied were positively correlated with accuracy, we empirically demonstrated that metrics based on specificity-sensitivity and sensitivity-precision are better for testing models, considering that most SDMs are based on unbalanced data. Without independent field validation, we found that using an arbitrary threshold for modelling can be a precarious approach with many possible outcomes, even after getting good evaluation scores. Bioacoustics proved to be important for validating SDMs for the six bat species analyzed, allowing a better refinement of SDMs in large and under-sampled regions, with relatively low sampling effort. Regardless of the species assessing method used, our research highlighted the vital necessity of in situ validation for SDMs.

Room Temperature Resonant Tunneling and Coulomb Blockade in Nanocrystalline Si with Double SiO2

2003 ◽  
Vol 794 ◽  
Author(s):  
Barriers L. C. Wu ◽  
K. J. Chen ◽  
M. Dai ◽  
W. Li ◽  
L. W. Yu ◽  
...  
Keyword(s):  
Coulomb Blockade ◽  
Resonant Tunneling ◽  
Room Temperature ◽  
Energy Levels ◽  
Chemical Vapor ◽  
Theoretical Evaluation ◽  
Capacitance Voltage ◽  
Charging Effect ◽  
Nanocrystalline Si

ABSTRACTWe studied electron resonant tunneling and Coulomb blockade in nanocrystalline Si (nc-Si) with double SiO2 barriers, which is fabricated in-situ in a plasma enhanced chemical vapor deposition system. In capacitance-voltage measurements, discrete capacitance peaks due to electron resonant tunneling into energy levels of nc-Si dots and Coulomb blockade charging in nc-Si dots have been observed at room temperature. For smaller dots, capacitance peaks are more distinct due to the stronger Coulomb blockade effect. Meanwhile, conductance plateau in the region of capacitance peaks are also observed due to the charging effect in nc-Si dots. Experimental results are in agreement with theoretical evaluation based on the model of Coulomb blockade.

scholarly journals Bioacoustics for in situ validation of species distribution modelling: An example with bats in Brazil

2021 ◽  
Author(s):  
Frederico Hintze ◽  
Ricardo B. Machado ◽  
Enrico Bernard
Keyword(s):  
Species Distribution ◽  
Large Scale ◽  
Species Distribution Modelling ◽  
Evaluation Metrics ◽  
Sampling Effort ◽  
International Treaties ◽  
Theoretical Evaluation ◽  
Distribution Modelling ◽  
Independent Field

AbstractSpecies distribution modelling (SDM) gained importance on biodiversity distribution and conservation studies worldwide, including prioritizing areas for public policies and international treaties. Useful for large-scale approaches and estimates, is a plus considering that a minor fraction of the planet is adequately sampled. However, SDM needs to be as reliable as possible. Minimizing errors is challenging, but essential, considering the uses and consequences of such models. In situ validation of the SDM outputs should be a key-step – in some cases, urgent. Bioacoustics can be used to validate and refine those outputs, especially if the focal species’ vocalizations are conspicuous and species-specific. This is the case of echolocating bats. Here, we used extensive acoustic monitoring (>120 validation points, covering >758,000 km2, and >300,000 sound files) to validate MaxEnt outputs for six neotropical bat species in a poorly-sampled region of Brazil. Based on in situ validation, we evaluated four threshold-dependent theoretical evaluation metrics’ ability in predicting models’ performance. We also assessed the performance of three widely used thresholds to convert continuous SDMs into presence/absence maps. We demonstrated that MaxEnt produces very different outputs, requiring a careful choice on thresholds and modeling parameters. Although all theoretical evaluation metrics studied were positively correlated with accuracy, we empirically demonstrated that metrics based on specificity-sensitivity and sensitivity-precision are better for testing models, considering that most SDMs are based on unbalanced data. Without independent field validation, we found that using an arbitrary threshold for modelling can be a precarious approach with many possible outcomes, even after getting good evaluation scores. Bioacoustics proved to be important for validating SDMs for the six bat species analyzed, allowing a better refinement of SDMs in large and under-sampled regions, with relatively low sampling effort. Regardless of species assessing method used, our research highlighted the vital necessity of in situ validation for SDMs.

Rendez vous with Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock
Keyword(s):  
Solar Energy ◽  
Electric Propulsion ◽  
Power Source ◽  
Propulsion System ◽  
Low Thrust ◽  
Ring Plane ◽  
The Earth ◽  
Total Impulse ◽  
Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

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