Photovoltaic(PV)power forecasting is essential for balancing energy supply and demand in renewable energy systems.However,the performance of PV panels varies across different technologies due to differences in efficie...Photovoltaic(PV)power forecasting is essential for balancing energy supply and demand in renewable energy systems.However,the performance of PV panels varies across different technologies due to differences in efficiency and how they process solar radiation.This study evaluates the effectiveness of deep learning models in predicting PV power generation for three panel technologies:Hybrid-Si,Mono-Si,and Poly-Si,across three forecasting horizons:1-step,12-step,and 24-step.Among the tested models,the Convolutional Neural Network—Long Short-Term Memory(CNN-LSTM)architecture exhibited superior performance,particularly for the 24-step horizon,achieving R^(2)=0.9793 and MAE 0.0162 for the Poly-Si array,followed by Mono-Si(R^(2)=0.9768)and Hybrid-Si arrays(R^(2)=0.9769).These findings demonstrate that the CNN-LSTM model can provide accurate and reliable PV power predictions for all studied technologies.By identifying the most suitable predictive model for each panel technology,this study contributes to optimizing PV power forecasting and improving energy management strategies.展开更多
The behavior of non-Newtonian power-law nanofluids under free convection heat transfer conditions in a cooled square enclosure equipped with a heated fin is investigated numerically.In particular,the impact of nanoflu...The behavior of non-Newtonian power-law nanofluids under free convection heat transfer conditions in a cooled square enclosure equipped with a heated fin is investigated numerically.In particular,the impact of nanofluids,composed of water and Al_(2)O_(3),TiO_(2),and Cu nanoparticles,on heat transfer enhancement is examined.The aim of this research is also to analyze the influence of different parameters,including the Rayleigh number(Ra=10^(4)-10^(6)),nanoparticle volume fraction(φ=0%-20%),non-Newtonian power-law indexes(n=0.6-1.4),and fin dimensions(Ar=0.3,0.5,and 0.7).Streamlines and isotherms are used to depict flow and related heat transfer characteristics.Results indicate that thermal performance improves with increasing Rayleigh number,regardless of the nanoparticle type or nanofluid rheological behavior.This suggests that the buoyancy force has a significant impact on heat transfer,particularly near the heat source.The Nusselt number is more sensitive to variations in Cu nanoparticle volume fractions compared to Al₂O₃and TiO₂.Moreover,the average Nusselt numbers for power-law nanofluids with n<1(n>1)are greater(smaller)than for Newtonian fluids due to the decrease(increase)in viscosity with increasing(decreasing)shear rate,at the same values of Rayleigh number Ra owing to the amplification(attenuation)of the convective transfer.Notably,the most substantial enhancement is observed with Cu-water shear-thinning nanofluid,where the Nusselt number increases by 136%when changing from Newtonian to shear thinning behavior and by 154.9%when adding 16%nanoparticle volume fraction.Moreover,an even larger increase of 57%in the average Nusselt number is obtained on increasing the fin length from 0.3 to 0.7.展开更多
This study focuses on the improvement of the thermal stability and flame-retardant performance of polyurethane(PU)foam by using effective flame-retardant additives and nano silica(nSiO_(2))particles from rice husk.The...This study focuses on the improvement of the thermal stability and flame-retardant performance of polyurethane(PU)foam by using effective flame-retardant additives and nano silica(nSiO_(2))particles from rice husk.The addition of non-halogen flame retardants(FRs)including aluminum trihydroxide(ATH),triphenyl phosphate(TPP),and diammonium phosphate(DAP)leads to markedly enhanced thermal sta-bility and fire resistance of the PU/nSiO_(2)/FRs nanocomposites,resulting in achieving UL-94 HB standard.In particular,the nanocomposites met the UL-94 V-0 criteria thanks to the inclusion of DAP at 25 phr.The LOI value of the nanocomposites reached 26%which is much higher than that of PU/nSiO_(2)nanocompos-ite,about 20%.In order to further understand the fire-proof mechanism,the residue char layer remaining of the PU/nSiO_(2)/FRs nanocomposites after being burned was also investigated by scanning electron mi-croscopy(SEM)and Fourier transform infrared(FTIR).In addition,the microstructure,thermal stability,thermal conductivity,and mechanical properties of nanocomposites were also evaluated in this study.展开更多
Fast recovery and minimum utilization of resources are the two main criteria for determining the protection scheme quality. We address the problem of providing a hybrid protection approach on elastic optical networks ...Fast recovery and minimum utilization of resources are the two main criteria for determining the protection scheme quality. We address the problem of providing a hybrid protection approach on elastic optical networks under contiguity and continuity of available spectrum constraints. Two main hypotheses are used in this paper for backup paths computation. In the first case, it is assumed that backup paths resources are dedicated. In the second case, the assumption is that backup paths resources are available shared resources. The objective of the study is to minimize spectrum utilization to reduce blocking probability on a network. For this purpose, an efficient survivable Hybrid Protection Lightpath （HybPL） algorithm is proposed for providing shared or dedicated backup path protection based on the efficient energy calculation and resource availability. Traditional First-Fit and Best-Fit schemes are employed to search and assign the available spectrum resources. The simulation results show that HybPL presents better performance in terms of blocking probability, compared with the Minimum Resources Utilization Dedicated Protection （MRU-DP） algorithm which offers better performance than the Dedicated Protection （DP） algorithm.展开更多
Fiber Bragg grating(FBG)sensors are often used in monitoring activities and to ensure that environmental parameters satisfy industrial requirements.They offer crucial safety measures in the early detection of hazards ...Fiber Bragg grating(FBG)sensors are often used in monitoring activities and to ensure that environmental parameters satisfy industrial requirements.They offer crucial safety measures in the early detection of hazards due to their greatly reduced size,low weight,flexibility,and immunity to electromagnetic interference.These characteristics make FBGs suitable also for use in relation to the human body for in vivo measurements and long-term monitoring.In this study,recent developments are presented with regard to the utilization of these sensors to measure the so-called post-mortem interval(PMI).Such developments rely on numerical simulations based on the Matlab software and monitoring of the rectal temperature,which is one of the main parameters for estimating the PMI.First,the Matlab software is used to solve the Henssge equation for different ambient temperatures and for different body masses;then a Bragg grating sensors is used for post-mortem dating.The results and their accuracy are discussed.展开更多
The performance of a 1.5 MVA wind-power Doubly Fed Induction Generator （DFIG） under network fault is studied using simulator developed in MATLAB-SIMULINK. This paper investigates a new control method able to improve...The performance of a 1.5 MVA wind-power Doubly Fed Induction Generator （DFIG） under network fault is studied using simulator developed in MATLAB-SIMULINK. This paper investigates a new control method able to improve the fault-ride through capability of DFIG. In such generators the appearance of severe voltage sags at the coupling point make highlight important over currents at the rotor/stator windings, making the use of crowbar protection device necessary and inevitable in order to protect the machine as well as the rotor side power converter. The simulator consists of the DFIG analytical model, power transformer model and the detailed frequency converter model including crowbar protection device. Simulation results are carried out to show the transient behavior of the DFIG when a sudden voltage dip is introduced with and without the crowbar implementation.展开更多
Owing to their high color purity,tunable bandgap,and high efficiency,quantum dots(QDs)have gained significant attention as color conversion materials for high-end display applications.Moreover,inkjet-printed QD pixels...Owing to their high color purity,tunable bandgap,and high efficiency,quantum dots(QDs)have gained significant attention as color conversion materials for high-end display applications.Moreover,inkjet-printed QD pixels show great potential for realizing full-color mini/micro-light emitting diode(micro-LED)-based displays.As a color conversion layer,the photoluminescence intensity of QDs is limited by the insufficient absorptance of the excitation light due to the lack of scattering.Conventional scatterers,such as titanium dioxide microparticles,have been applied after additional surface engineering for sufficient dispersity to prevent nozzle clogging in inkjet printing process.In our work,as an alternative approach,we use inkjet printing for depositing a phase separating polymer ink based on polystyrene(PS)and polyethylene glycol(PEG).QD/polymer composite pixels with scattering micropores are realized.The morphology of the micropores can be tailored by the weight ratio between PS and PEG which enables the manipulation of scattering capability.With the presence of the microporous structure,the photoluminescence intensity of the QD film is enhanced by 110%in drop-cast films and by 35.3%in inkjet-printed QD pixel arrays compared to the reference samples.展开更多
Due to the increasing pressure brought by recent global environmental problems,building designers are embracing regionalism and the knowledge of traditional structures,arguing that these structures are energy efficien...Due to the increasing pressure brought by recent global environmental problems,building designers are embracing regionalism and the knowledge of traditional structures,arguing that these structures are energy efficient and highly sustainable.We observe clear evidence of the increasing interest in vernacular architecture among the research community.This study therefore aims to clarify the contents and issues raised in the studies on vernacular architecture and the knowledge and recommendations that can be derived from them.A database of the research is established by collecting many studies from primary sources.Obtained data is carefully refined and categorized into a table where synthesized information is introduced.The results of this study show an uneven geographic and climatic distribution of the studies;the trend in selecting research objectives and research objects;the choice of research methods with a clear shift towards quantitative research methods,and the generic findings from the database of the research.These results can support diverse inquiries about vernacular architecture across the world and be used as a resource or an orientation to support numerous subsequent studies.展开更多
文摘Photovoltaic(PV)power forecasting is essential for balancing energy supply and demand in renewable energy systems.However,the performance of PV panels varies across different technologies due to differences in efficiency and how they process solar radiation.This study evaluates the effectiveness of deep learning models in predicting PV power generation for three panel technologies:Hybrid-Si,Mono-Si,and Poly-Si,across three forecasting horizons:1-step,12-step,and 24-step.Among the tested models,the Convolutional Neural Network—Long Short-Term Memory(CNN-LSTM)architecture exhibited superior performance,particularly for the 24-step horizon,achieving R^(2)=0.9793 and MAE 0.0162 for the Poly-Si array,followed by Mono-Si(R^(2)=0.9768)and Hybrid-Si arrays(R^(2)=0.9769).These findings demonstrate that the CNN-LSTM model can provide accurate and reliable PV power predictions for all studied technologies.By identifying the most suitable predictive model for each panel technology,this study contributes to optimizing PV power forecasting and improving energy management strategies.
基金financial support by Campus France within the framework of the PHC-Maghreb 45990SH Projectsupport from the Tunisian Republic Ministry of Higher Education and Scientific Research for a part of her stay in France.
文摘The behavior of non-Newtonian power-law nanofluids under free convection heat transfer conditions in a cooled square enclosure equipped with a heated fin is investigated numerically.In particular,the impact of nanofluids,composed of water and Al_(2)O_(3),TiO_(2),and Cu nanoparticles,on heat transfer enhancement is examined.The aim of this research is also to analyze the influence of different parameters,including the Rayleigh number(Ra=10^(4)-10^(6)),nanoparticle volume fraction(φ=0%-20%),non-Newtonian power-law indexes(n=0.6-1.4),and fin dimensions(Ar=0.3,0.5,and 0.7).Streamlines and isotherms are used to depict flow and related heat transfer characteristics.Results indicate that thermal performance improves with increasing Rayleigh number,regardless of the nanoparticle type or nanofluid rheological behavior.This suggests that the buoyancy force has a significant impact on heat transfer,particularly near the heat source.The Nusselt number is more sensitive to variations in Cu nanoparticle volume fractions compared to Al₂O₃and TiO₂.Moreover,the average Nusselt numbers for power-law nanofluids with n<1(n>1)are greater(smaller)than for Newtonian fluids due to the decrease(increase)in viscosity with increasing(decreasing)shear rate,at the same values of Rayleigh number Ra owing to the amplification(attenuation)of the convective transfer.Notably,the most substantial enhancement is observed with Cu-water shear-thinning nanofluid,where the Nusselt number increases by 136%when changing from Newtonian to shear thinning behavior and by 154.9%when adding 16%nanoparticle volume fraction.Moreover,an even larger increase of 57%in the average Nusselt number is obtained on increasing the fin length from 0.3 to 0.7.
基金funded by the Vietnam National University Ho Chi Minh City(VNU-HCM)under grant number C2022-18-41.
文摘This study focuses on the improvement of the thermal stability and flame-retardant performance of polyurethane(PU)foam by using effective flame-retardant additives and nano silica(nSiO_(2))particles from rice husk.The addition of non-halogen flame retardants(FRs)including aluminum trihydroxide(ATH),triphenyl phosphate(TPP),and diammonium phosphate(DAP)leads to markedly enhanced thermal sta-bility and fire resistance of the PU/nSiO_(2)/FRs nanocomposites,resulting in achieving UL-94 HB standard.In particular,the nanocomposites met the UL-94 V-0 criteria thanks to the inclusion of DAP at 25 phr.The LOI value of the nanocomposites reached 26%which is much higher than that of PU/nSiO_(2)nanocompos-ite,about 20%.In order to further understand the fire-proof mechanism,the residue char layer remaining of the PU/nSiO_(2)/FRs nanocomposites after being burned was also investigated by scanning electron mi-croscopy(SEM)and Fourier transform infrared(FTIR).In addition,the microstructure,thermal stability,thermal conductivity,and mechanical properties of nanocomposites were also evaluated in this study.
文摘Fast recovery and minimum utilization of resources are the two main criteria for determining the protection scheme quality. We address the problem of providing a hybrid protection approach on elastic optical networks under contiguity and continuity of available spectrum constraints. Two main hypotheses are used in this paper for backup paths computation. In the first case, it is assumed that backup paths resources are dedicated. In the second case, the assumption is that backup paths resources are available shared resources. The objective of the study is to minimize spectrum utilization to reduce blocking probability on a network. For this purpose, an efficient survivable Hybrid Protection Lightpath （HybPL） algorithm is proposed for providing shared or dedicated backup path protection based on the efficient energy calculation and resource availability. Traditional First-Fit and Best-Fit schemes are employed to search and assign the available spectrum resources. The simulation results show that HybPL presents better performance in terms of blocking probability, compared with the Minimum Resources Utilization Dedicated Protection （MRU-DP） algorithm which offers better performance than the Dedicated Protection （DP） algorithm.
文摘Fiber Bragg grating(FBG)sensors are often used in monitoring activities and to ensure that environmental parameters satisfy industrial requirements.They offer crucial safety measures in the early detection of hazards due to their greatly reduced size,low weight,flexibility,and immunity to electromagnetic interference.These characteristics make FBGs suitable also for use in relation to the human body for in vivo measurements and long-term monitoring.In this study,recent developments are presented with regard to the utilization of these sensors to measure the so-called post-mortem interval(PMI).Such developments rely on numerical simulations based on the Matlab software and monitoring of the rectal temperature,which is one of the main parameters for estimating the PMI.First,the Matlab software is used to solve the Henssge equation for different ambient temperatures and for different body masses;then a Bragg grating sensors is used for post-mortem dating.The results and their accuracy are discussed.
文摘The performance of a 1.5 MVA wind-power Doubly Fed Induction Generator （DFIG） under network fault is studied using simulator developed in MATLAB-SIMULINK. This paper investigates a new control method able to improve the fault-ride through capability of DFIG. In such generators the appearance of severe voltage sags at the coupling point make highlight important over currents at the rotor/stator windings, making the use of crowbar protection device necessary and inevitable in order to protect the machine as well as the rotor side power converter. The simulator consists of the DFIG analytical model, power transformer model and the detailed frequency converter model including crowbar protection device. Simulation results are carried out to show the transient behavior of the DFIG when a sudden voltage dip is introduced with and without the crowbar implementation.
基金the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)under Germany’s Excellence Strategy via the Excellence Cluster 3D Matter Made to Order(EXC-2082/1-390761711)through the DFG priority program SPP 1839“Tailored disorder”.
文摘Owing to their high color purity,tunable bandgap,and high efficiency,quantum dots(QDs)have gained significant attention as color conversion materials for high-end display applications.Moreover,inkjet-printed QD pixels show great potential for realizing full-color mini/micro-light emitting diode(micro-LED)-based displays.As a color conversion layer,the photoluminescence intensity of QDs is limited by the insufficient absorptance of the excitation light due to the lack of scattering.Conventional scatterers,such as titanium dioxide microparticles,have been applied after additional surface engineering for sufficient dispersity to prevent nozzle clogging in inkjet printing process.In our work,as an alternative approach,we use inkjet printing for depositing a phase separating polymer ink based on polystyrene(PS)and polyethylene glycol(PEG).QD/polymer composite pixels with scattering micropores are realized.The morphology of the micropores can be tailored by the weight ratio between PS and PEG which enables the manipulation of scattering capability.With the presence of the microporous structure,the photoluminescence intensity of the QD film is enhanced by 110%in drop-cast films and by 35.3%in inkjet-printed QD pixel arrays compared to the reference samples.
文摘Due to the increasing pressure brought by recent global environmental problems,building designers are embracing regionalism and the knowledge of traditional structures,arguing that these structures are energy efficient and highly sustainable.We observe clear evidence of the increasing interest in vernacular architecture among the research community.This study therefore aims to clarify the contents and issues raised in the studies on vernacular architecture and the knowledge and recommendations that can be derived from them.A database of the research is established by collecting many studies from primary sources.Obtained data is carefully refined and categorized into a table where synthesized information is introduced.The results of this study show an uneven geographic and climatic distribution of the studies;the trend in selecting research objectives and research objects;the choice of research methods with a clear shift towards quantitative research methods,and the generic findings from the database of the research.These results can support diverse inquiries about vernacular architecture across the world and be used as a resource or an orientation to support numerous subsequent studies.
