scholarly journals In-Situ Measurement of Power Loss for Crystalline Silicon Modules Undergoing Thermal Cycling and Mechanical Loading Stress Testing

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 72
Author(s):  
Sergiu Spataru ◽  
Peter Hacke ◽  
Dezso Sera
Keyword(s):  
Thermal Cycling ◽  
Power Loss ◽  
Stress Testing ◽  
Series Resistance ◽  
Short Circuit ◽  
In Situ Measurement ◽  
Mechanical Degradation ◽  
Model Parameters ◽  
The Impact

An in-situ method is proposed for monitoring and estimating the power degradation of mc-Si photovoltaic (PV) modules undergoing thermo-mechanical degradation tests that primarily manifest through cell cracking, such as mechanical load tests, thermal cycling and humidity freeze tests. The method is based on in-situ measurement of the module’s dark current-voltage (I-V) characteristic curve during the stress test, as well as initial and final module flash testing on a Sun simulator. The method uses superposition of the dark I-V curve with final flash test module short-circuit current to account for shunt and junction recombination losses, as well as series resistance estimation from the in-situ measured dark I-Vs and final flash test measurements. The method is developed based on mc-Si standard modules undergoing several stages of thermo-mechanical stress testing and degradation, for which we investigate the impact of the degradation on the modules light I-V curve parameters, and equivalent solar cell model parameters. Experimental validation of the method on the modules tested shows good agreement between the in-situ estimated power degradation and the flash test measured power loss of the modules, of up to 4.31 % error (RMSE), as the modules experience primarily junction defect recombination and increased series resistance losses. However, the application of the method will be limited for modules experiencing extensive photo-current degradation or delamination, which are not well reflected in the dark I-V characteristic of the PV module.

In Situ Measurement of Breathing Strain and Mechanical Degradation in Organic Electrochromic Polymers

2020 ◽  
Vol 12 (45) ◽  
pp. 50889-50895
Author(s):  
Xiaokang Wang ◽  
Luize Scalco de Vasconcelos ◽  
Ke Chen ◽  
Kuluni Perera ◽  
Jianguo Mei ◽  
...  
Keyword(s):  
In Situ Measurement ◽  
Mechanical Degradation ◽  
Electrochromic Polymers

scholarly journals Agent-based modelling of complex factors impacting malaria prevalence

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Miracle Amadi ◽  
Anna Shcherbacheva ◽  
Heikki Haario
Keyword(s):  
Malaria Transmission ◽  
Field Data ◽  
Control Measures ◽  
Model Parameters ◽  
Economic Factors ◽  
Agent Based ◽  
Wide Range ◽  
The Impact ◽  
Socio Economic Factors

Abstract Background Increasingly complex models have been developed to characterize the transmission dynamics of malaria. The multiplicity of malaria transmission factors calls for a realistic modelling approach that incorporates various complex factors such as the effect of control measures, behavioural impacts of the parasites to the vector, or socio-economic variables. Indeed, the crucial impact of household size in eliminating malaria has been emphasized in previous studies. However, increasing complexity also increases the difficulty of calibrating model parameters. Moreover, despite the availability of much field data, a common pitfall in malaria transmission modelling is to obtain data that could be directly used for model calibration. Methods In this work, an approach that provides a way to combine in situ field data with the parameters of malaria transmission models is presented. This is achieved by agent-based stochastic simulations, initially calibrated with hut-level experimental data. The simulation results provide synthetic data for regression analysis that enable the calibration of key parameters of classical models, such as biting rates and vector mortality. In lieu of developing complex dynamical models, the approach is demonstrated using most classical malaria models, but with the model parameters calibrated to account for such complex factors. The performance of the approach is tested against a wide range of field data for Entomological Inoculation Rate (EIR) values. Results The overall transmission characteristics can be estimated by including various features that impact EIR and malaria incidence, for instance by reducing the mosquito–human contact rates and increasing the mortality through control measures or socio-economic factors. Conclusion Complex phenomena such as the impact of the coverage of the population with long-lasting insecticidal nets (LLINs), changes in behaviour of the infected vector and the impact of socio-economic factors can be included in continuous level modelling. Though the present work should be interpreted as a proof of concept, based on one set of field data only, certain interesting conclusions can already be drawn. While the present work focuses on malaria, the computational approach is generic, and can be applied to other cases where suitable in situ data is available.

scholarly journals A novel temperature controller for in-situ measurement of radiation-induced changes in temperature effects on space electronics

2019 ◽  
Vol 70 (3) ◽  
pp. 227-235
Author(s):  
Jiri Haze ◽  
Jiri Hofman
Keyword(s):  
In Situ Measurement ◽  
Test Method ◽  
Space Applications ◽  
Temperature Controller ◽  
Space Electronics ◽  
Radiation Induced ◽  
Induced Changes ◽  
The Impact ◽  
Related Test

Abstract The paper discusses a novel temperature controller and a related test method allowing in-situ measurement of total ionising dose-induced changes in the impact of temperature on electronic devices for space applications. Various results of pilot radiation experiments (testing commercial PMOS transistors, RADFETs, and voltage references) are also presented.

scholarly journals How should sparse in situ measurements be compared to continuous model data?

2012 ◽  
Vol 5 (3) ◽  
pp. 2311-2345 ◽  
Author(s):  
L. de Mora ◽  
M. Butenschön ◽  
J. I. Allen
Keyword(s):  
Time Series Data ◽  
Model Performance ◽  
Previous Method ◽  
In Situ Measurements ◽  
Point Method ◽  
In Situ Measurement ◽  
Series Data ◽  
Point To Point ◽  
The Impact

Abstract. This work demonstrates the importance of an adequate method to sub-sample model results when comparing with in situ measurements. A test of model skill was performed by comparing a multi-decadal hindcast against a sparse, unevenly distributed historic in situ dataset. The comparison was performed using a point-to-point method. The point-to-point method masked out all hindcast cells that did not have a corresponding in situ measurement in order to compare each in situ measurement against its most similar cell from the model. The application of the point-to-point method showed that the model was successful at reproducing many inter-annual trends. Furthermore, this success was not immediately apparent using the previous comparison methods, which compared model and measurements aggregated to regional averages. Time series, data density and target diagrams were employed to illustrate the impact of switching from the previous method to the point-to-point method. The comparison based on regional averages gave significantly different and sometimes contradicting results that could lead to erroneous conclusions on the model performance. We therefore recommend that researchers take into account for the limitations of the in situ datasets, process the model to resemble the data as much as possible, and we advocate greater transparency in the publication of methodology.

scholarly journals Analysis of power system operation at asymmetrical load

2018 ◽  
Vol 19 ◽  
pp. 01029
Author(s):  
Stefan Paszek ◽  
Adrian Nocoń ◽  
Piotr Pruski
Keyword(s):  
Power System ◽  
Short Circuit ◽  
Synchronous Generator ◽  
Angular Speed ◽  
Power Line ◽  
Model Parameters ◽  
System Operation ◽  
Two Phase ◽  
The Impact ◽  
Generator Stator

The paper presents a mathematical model of a power system (PS) consisting of a generating unit (with a synchronous generator) connected by a high voltage (transmission) power line to a bus. The state and output equations of the generator are expressed in the coordinate system d, q, 0 and with the use of phase quantities of the generator stator, the bus and the power line, which is especially useful in the analysis of asymmetrical states. A disturbance of the steady state in the form of a two-phase short-circuit in the transmission line was taken into account in the made calculations. The influence of the excitation system and angular speed control system of the generator as well as the impact of selected generator model parameters on the waveforms were investigated.

scholarly journals Water budget, performance of evapotranspiration formulations, and their impact on hydrological modeling of a small boreal peatland-dominated watershed

2018 ◽  
Vol 55 (2) ◽  
pp. 206-220 ◽  
Author(s):  
Pierre-Erik Isabelle ◽  
Daniel F. Nadeau ◽  
Alain N. Rousseau ◽  
François Anctil
Keyword(s):  
Water Budget ◽  
Hydrological Modeling ◽  
Distributed Model ◽  
Model Parameters ◽  
Taylor Models ◽  
Physically Based ◽  
Model Efficiency ◽  
The Impact ◽  
Substantial Drop

Peatlands occupy around 13% of the land cover of Canada, and thus they play a key role in the water balance at high latitudes. They are well known for having substantial water loss due to evapotranspiration. Since measurements of evapotranspiration are scarce over these environments, hydrologists generally rely on models of varying complexity to evaluate these water exchanges in the global watershed balance. This study quantifies the water budget of a small boreal peatland-dominated watershed. We assess the performance of three evapotranspiration models in comparison with in situ observations and the impact of using these models in the hydrological modeling of the watershed. The study site (∼1 km2) is located in the eastern James Bay lowlands, Québec, Canada. During summer 2012, an eddy flux tower measured evapotranspiration continuously, while a trapezoidal flume monitored streamflow at the watershed outlet. We estimated evapotranspiration with a combinational model (Penman), a radiation-based model (Priestley–Taylor), and a temperature-based model (Hydro-Québec), and performed the hydrological modeling of the watershed with HYDROTEL, a physically based semi-distributed model. Our results show that the Penman and Priestley–Taylor models reproduce the observations with the highest precision, while a substantial drop in performance occurs with the Hydro-Québec model. However, these discrepancies did not appear to reduce the hydrological model efficiency, at least from what can be concluded from a 3-month modeling period. HYDROTEL appears sensitive to evapotranspiration inputs, but calibration of model parameters can compensate for the differences. These findings still need to be confirmed with longer modeling periods.

scholarly journals How should sparse marine in situ measurements be compared to a continuous model: an example

2013 ◽  
Vol 6 (2) ◽  
pp. 533-548 ◽  
Author(s):  
L. de Mora ◽  
M. Butenschön ◽  
J. I. Allen
Keyword(s):  
Time Series Data ◽  
Model Performance ◽  
Continuous Model ◽  
In Situ Measurements ◽  
Point Method ◽  
In Situ Measurement ◽  
Series Data ◽  
Point To Point ◽  
The Impact

Abstract. This work demonstrates an example of the importance of an adequate method to sub-sample model results when comparing with in situ measurements. A test of model skill was performed by employing a point-to-point method to compare a multi-decadal hindcast against a sparse, unevenly distributed historic in situ dataset. The point-to-point method masked out all hindcast cells that did not have a corresponding in situ measurement in order to match each in situ measurement against its most similar cell from the model. The application of the point-to-point method showed that the model was successful at reproducing the inter-annual variability of the in situ datasets. Furthermore, this success was not immediately apparent when the measurements were aggregated to regional averages. Time series, data density and target diagrams were employed to illustrate the impact of switching from the regional average method to the point-to-point method. The comparison based on regional averages gave significantly different and sometimes contradicting results that could lead to erroneous conclusions on the model performance. Furthermore, the point-to-point technique is a more correct method to exploit sparse uneven in situ data while compensating for the variability of its sampling. We therefore recommend that researchers take into account for the limitations of the in situ datasets and process the model to resemble the data as much as possible.

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