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Spatiotemporal assessment and monitoring of urban heat islands in metropolitan areas using machine learning and downscaling

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SUSTAINABLE CITIES AND SOCIETY 2025年 126卷

作者： Sampaio, Rafael Joao Rodriguez, Daniel Andres Espindola, Rogerio Pinto da Silva, Fabricio Polifke Univ Fed Rio de Janeiro Civil Engn Program Water Resources & Environm Lab LABH2O COPPE Rio De Janeiro Brazil Univ Fed Rio de Janeiro Technol Transfer Ctr NTT Civil Engn Program COPPE Rio De Janeiro Brazil Univ Fed Rio de Janeiro Inst Geosci Dept Meteorol Very Short Term Forecasting & Extreme Events Lab L Rio De Janeiro Brazil

Urban heat islands (UHI) are a significant phenomenon that results from human modification of the land. numerical models that are used to study the impacts of UHIs on air temperature require high resolution to estimate spatial fields *** study employs both statistical and dynamic downscaling methods to estimate urban heat islands (UHI) from 1 km-resolution air temperature fields from outputs of the Weather Research and Forecasting (WRF) model, initially generated at a coarser resolution of 5 km, for the Metropolitan Area of Rio de Janeiro (MARJ). In the dynamic method, a grid with 1 km spatial resolution is obtained through a nesting system with three domains of the WRF model of 25-5-1 km. The latter domain couples to the Single-Layer Urban Canopy Model (SLUCM). The statistical approach introduces a novel methodology based on the extreme gradient boosting machine learning algorithm, which correlates air temperature with physiographic landscape variables on a scale of 1 km by 1 multiple nonlinear regression. Additionally, SHAP analysis is applied to assess individual feature contributions in the machine learning model. The performance of theses downscaling methods is evaluated using atmospheric temperature measured at meteorological stations and estimated from remote sensing data. Both methods satisfactorily simulate the temporal and spatial behavior of UHIs in the metropolitan region of Rio de Janeiro, however, the statistical approach demonstrates significantly lower computational costs. This result demonstrates the feasibility of this machine learning-based approach as an alternative for studying and monitoring UHI with limited computational resources.

关键词： Urban heat island Statistical downscaling Machine learning numeric modeling

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modeling of inductive constant power load for electromagnetic-transient simulations-Part II

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ELECTRIC POWER SYSTEMS RESEARCH 2025年 242卷

作者： Alboaouh, Kamel Velaga, Yaswanth Nag Prabakar, Kumaraguru Norfolk State Univ Dept Engn Tech 700 Pk AveRTC BldgSuite 420M Norfolk VA 23501 USA Nat Renewable Energy Lab Power Syst Engn Ctr Golden CO USA

This paper improves the dynamic constant power (CP) load model that was published in Part I, which is appropriate for electromagnetic-transient (EMT). The improved model conserves all features of its predecessor. For instance, it maintains a fixed power consumption (both active and reactive parts) and a fixed power factor for loads that are predominantly inductive. Furthermore, as the proposed model is a time-dependent system, it is applicable to both sinusoidal and non-sinusoidal case studies. However, the previous model cannot be easily integrated with numeric solvers because it simulated load data over one cycle all together, not sequentially in a time-step manner, due to the limitation involved with the power factor. The improved version, on the contrary, allows the load to be simulated at every time step, which would facilitate its integration with numeric solvers. The model's validity is confirmed by comparing its response with data that is synthesized from constant impedance load, and the result is satisfactory.

关键词： EMT simulator Constant-power-load numeric modeling Load modeling

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Glacial isostatic adjustment in the Red Sea: Impact of 3-D Earth structure

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QUATERNARY SCIENCE REVIEWS 2022年 280卷 107415-107415页

作者： Peak, Barra A. Latychev, Konstantin Hoggard, Mark J. Mitrovica, Jerry X. Harvard Univ Dept Earth & Planetary Sci 20 Oxford St Cambridge MA 02318 USA Australia Natl Univ Res Sch Earth Sci 142 Mills Rd Acton ACT 0200 Australia Univ Colorado Dept Geol Sci 2200 Colorado Ave Boulder CO 80309 USA

Sea-level history in the Red Sea region has commonly been interpreted as an accurate proxy for global mean sea level (GMSL), which can be used to constrain global ice volumes and inform a diverse range of regional paleoclimate studies. Previous modeling work has demonstrated, however, that glacial isostatic adjustment (GIA) processes may introduce significant departures from GMSL in this region. The GIA signal is a complex combination of deformational, gravitational, and rotational effects arising from shifting ice and water surface loads and consists of long-wavelength effects superimposed by a short-wavelength signal associated with "continental levering" - a response to local meltwater loading. In this study, we revisit the effects of GIA in the Red Sea region using Earth models characterized by 3-D variations in mantle viscoelastic structure and lithospheric thickness, focusing on the period from Last Glacial Maximum (LGM) to present day. We find that the presence of the Red Sea Rift and low-viscosity upper mantle acts to amplify sea-level rise associated with continental levering, yielding a more pronounced rise for sites toward the center of the Red Sea during deglaciation in comparison to GMSL. In contrast, coastal sites experience a net GIA-induced sea-level fall that acts in opposition to the GMSL rise. Furthermore, while the maximum departure from GMSL occurs close to LGM for northern sites, the GIA signal can peak as late as 14 Ica for southern sites. Simulations based on 3-D Earth models tend to show a smaller departure from GMSL than 1-D predictions for most coastal sites, including at the Strait of Bab elMandeb at the mouth of the Red Sea, and typically peak at similar to 10 m. The opposite is true for sites close to the rift: at these locations the difference between the 1-D and 3-D simulations can reach similar to 20 m. We therefore conclude that any mapping from local sea level to GMSL is both location and time dependent and cannot be captured by a

关键词： Sea level changes Last glacial maximum numeric modeling Mantle viscosity Holocene

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Analysis of a passive vibration damper for high-speed superconducting magnetic bearings

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ENGINEERING RESEARCH EXPRESS 2024年第3期6卷 035524-035524页

作者： Baloochi, M. Espenhahn, T. Hossain, M. Perez-Delgado, Y. Abdkader, A. Beitelschmidt, M. Nielsch, K. Huehne, R. Leibniz Inst Solid State & Mat Res Helmholtzstr 20 D-01069 Dresden Germany TUD Dresden Univ Technol Inst Text Machinery & High Performance Mat Technol Fac Mech Sci & Engn Dresden Germany Tech Univ Dresden Inst Solid Mech IFKM Fac Mech Engn Chair Dynam & Mech Design Marschnerstr 30 D-01307 Dresden Germany

Superconducting magnetic bearings (SMB) based on a combination of high temperature superconductors and permanent magnets enable the realization of self-stabilized high-speed devices with significantly reduced friction. However, external vibration might couple in the bearing resulting in large amplitude oscillations due to a resonance case. A dedicated eddy current damper (ECD) might be used to eliminate these oscillations for a stable operation. The influence of such damping elements was studied for a frictionless SMB twisting system designed to speed up the conventional ring spinning process. Therefore, conductive copper rings with different thicknesses were implemented at different positions into the bearing setup as ECD. Afterward, the SMB setup was analyzed during acceleration using an array of laser distance sensors to record the displacement of the levitating permanent magnet ring in radial and axial direction, respectively. Simultaneously, a numerical model was developed to investigate the influence of the ECDs on the dynamic and static behavior of the SMB in more detail. It was shown that the simulated damping coefficients are in good agreement with the measured values, which allows further optimization of the ECD with the developed numerical model.

关键词： superconducting magnetic bearing eddy current damper high-speed rotation numeric modeling vibration analysis ring spinning

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Comparative Study on numerical Calculation of 2-D Random Sea Surface Based on Fractal Method and Monte Carlo Method

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WATER 2020年第7期12卷 1871-1871页

作者： Wu, Gengkun Liu, Chuanxi Liang, Yongquan Shandong Univ Sci & Technol Coll Comp Sci & Engn Qingdao 266590 Peoples R China Shandong Univ Sci & Technol Coll Intelligent Equipment Tai An 271000 Shandong Peoples R China

Based on fifty one groups of data on direction distribution measured from buoy sites, several important spectrum parameters including distribution characteristics of the measured data's spectrum, the Wen's direction spectrum and the Donelan function are analyzed from the perspectives of standard deviation of directional distribution function and statistical results. Then, a numeric calculation model based on the Monte Carlo method is proposed in this work. At the same time-based on Weierstrass self-affine fractal function-numeric simulation of random sea surface is conducted by modifying the bilateral power law. The analysis of the numeric calculation results under different wind directions, speeds and fetches proves that both methods can be adopted for different water directional distributions and target spectrum models. In addition, this study compares the characteristic wave within different distribution frequency domains in the main wave direction and in its orthogonal direction. It is proved that the fractal method cannot fully reflect the anisotropy of gravity wave and tension wave in the superposition direction, however, it can maintain the similarity of overall energy part with the rough length of the waves. Moreover, there are still limitations of the fractal method in the numeric modeling of undeveloped sea surface.

关键词： Monte Carlo method fractal function distribution frequency domains numeric modeling undeveloped sea surface

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modeling tunnel currents in organic permeable-base transistors

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SYNTHETIC METALS 2019年 252卷 82-90页

作者： Al-Shadeedi, Akram Liu, Shiyi Krishnan, Raj Kishen Radha Keum, Chang-Min Kaphle, Vikash Bunge, Scott D. Lussem, Bjorn Kent State Univ Dept Phys Kent OH 44242 USA Kent State Univ Dept Chem & Biochem Kent OH 44242 USA Univ Baghdad Dept Phys Baghdad 10071 Iraq Univ St Andrews Sch Phys & Astron Organ Semicond Ctr SUPA St Andrews KY16 9SS Fife Scotland

Research in organic permeable base transistors (OPBTs) has led to a significant increase in their performance. However, despite this progress, understanding of the working mechanism of OPBTs is still limited. Although first numerical models of OPBTs are able to describe the switching mechanism of OPBTs correctly, they neglect currents injected at the base electrode, which leads to unrealistically low off-currents and high ON/OFF ratios. Here, a tunneling model is developed that is capable of describing injection of charges through a thin oxide layer formed around the base electrode of OPBTs. With the help of this injection model, the performance of the base collector diode of OPBTs is discussed. In particular, the model is used to explain the reduction in backward currents due to an exposure to ambient air by an increase in the thickness of the oxide layer. Furthermore, the tunnel model is used to show that the reduction in backward currents of the base collector diode leads to a decrease in off-currents of complete OPBTs, which in turn leads to an increase in their ON/OFF ratio.

关键词： Organic permeable-base transistors Tunnel-injection numeric modeling

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modeling a Flow around Permeable Surfaces

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Mathematical Models and Computer Simulations 2019年第4期11卷 531-541页

作者： Shevelev, Yu. D. Maksimov, F.A. Institute of Computer-Aided Design Russian Academy of Sciences Moscow Russian Federation

Abstract: The paper presents a method for calculating a flow around a permeable surface using a set of bodies modeling the impermeable part of the surface. The permeable surface is simulated by a finite relatively small number of elements determined by the available computer processing capabilities. The similarity between the aerodynamic properties of the surface in the mathematical model and the real surface is provided by the geometric similarity between the shape of the surface elements and the equal value of the permeability coefficient. Comparison of the calculation results with the experimental findings shows the possibility of a reasonably reliable prediction for the aerodynamic properties of permeable surfaces. An example is given of calculating the flow around tori with different geometric shapes, which shows that calculations can be carried out in a wide variation range of the permeability coefficient. Examples of calculating the flow around a permeable cone and cylinder are presented to demonstrate the possibility of modeling flows in the vicinity of complex configurations. A software package for modeling two-dimensional plane and axisymmetric flows near permeable surfaces is implemented. © 2019, Pleiades Publishing, Ltd.

关键词： aerodynamic properties numeric modeling permeable surface

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Left heart simulator for evaluation of prosthetic heart valves: behavior of tricuspid bioprosthetic mitral valves during diastole

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IFAC-PapersOnLine 2018年第27期51卷 134-139页

作者： Bazan, Ovandir Ortiz, Jayme Pinto Neto, Antonio Braulio Yanagihara, Jurandir Itizo Department of Mechanical Engineering of the Escola Politécnica of the University of São Paulo São Paulo Brazil

The purpose of this work was to know the characteristics of tricuspid bioprosthetic mitral valves in terms of velocity fields and valve aperture areas for some instants concerning the diastole. A left heart simulator was used as an in vitro platform for the bioprostheses. A particle image velocimetry (PIV) system was applied for characterizing instantaneous 2D-velocity fields within the left ventricular model (LVM), and also for detection of mitral bioprostheses aperture areas. The ventricular states were established for 60, 70 and 90 bpm (beats per minute) and a blood analog fluid based on glycerol was employed at 36.5±0.5ºC. Two mitral bioprostheses (nominal diameter of 27 and 31 mm) and an aortic bileaflet mechanical valve (27 mm diameter) were used. Instantaneous two-dimensional velocity fields at the upper part of the LVM, for two sections (in the middle of the LVM, and also in a section at 7 mm of distance from that) were obtained. Averaged velocity vector maps (N = 50) were calculated for some instants of interest. According to different heart rates, bioprostheses and sections within the LVM, the velocity fields were presented, as well the bioprostheses aperture areas. In conclusion, the experimental scope including different ventricular states showed how the inflow characteristics of the LVM change according to the chosen variables. This information will aid the validation of a numeric model for the LVM operation, which has been elaborated (some specific methods are presented in the Appendix). © 2018

关键词： Velocity Flow visualization Heart Simulators Valves (mechanical) Velocimeters Velocity measurement Bioprostheses Left ventricular Mechanical valves numeric modeling Prosthetic heart valve Two dimensional particle image velocimetry Velocity field Velocity vector maps

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Thermal Rehabilitation Influence upon the Comfort in Hospitals 5th

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5th International Conference on Advancements of Medicine and Health Care through Technology (MEDITECH)

作者： Abrudan, A. Rus, T. Mare, R. Tech Univ Cluj Napoca Bldg Serv Dept Cluj Napoca Romania

ISBN: (纸本)9783319528755;9783319528748

In Romania, most of the hospitals still have a relatively low level of thermal insulation, thus inside of building the microclimate conditions are continuously deteriorating, due to vapors condensation producing also an increase in heat losses, energy consumption and operational costs. The rehabilitation and modernizing can be applied successfully using energy efficient methods together with latest materials and technologies. The rehabilitation solutions are strictly binding to the required level of comfort required by a certain area, its occupancy pattern, its geographical location (urban or rural areas, etc.), etc. The thermal rehabilitation of hospitals buildings is a must in order to achieve the required interior microclimate conditions, increase the degree of environmental protection and reducing operational costs, regarding as well the investment costs involved. A special attention has to be given to the interior microclimate conditions required by the hospital specific activities conditions which are different compared to other buildings. This paper intends to present some of the possibilities to improve the thermal protection, the measurements being performed on a wall structure used for the construction of most hospitals in Romania, and for the thermal insulation two of the most used materials have been considered. The results of measurements have been processed through a mathematical modelling software, and the conclusion are demonstrating the need to reduce or eliminate the thermal bridges of any kind, especially in the intersection zone of building elements and around the openings for windows and doors in order to ensure optimal thermal comfort.

关键词： Keywords Hospitals thermal comfort thermal rehabilitation condensing numeric modeling

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Dynamic Study of Thermal Characteristics of Linear Induction Motors 15

Dynamic Study of Thermal Characteristics of Linear Induction...

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15th International Conference on Electrical Machines, Drives and Power Systems (ELMA)

作者： Sarapulov, F. Frizen, V. Smolyanov, I. Shmakov, E. Ural Fed Univ Dept Elect & Electrotechnol Syst Ekaterinburg Russia

ISBN: (纸本)9781509066919

Nowadays, the transport on a magnetic cushion meets more often. This makes it important to study and design this type of transport. The most important criterion of public transport is reliability. Therefore, in this article is considered the thermal characteristics of a linear induction machine under intensive track operation. Thermal characteristics are calculated using the method of detailed equivalent heat circuit. A brief analysis of the possibility of operation in different operating modes is given.

关键词： linear induction motor vehicle heating numeric modeling dynamic modeling equivalent heat circuit

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