scholarly journals Peculiarities of surface layer response to local and global variations of temperature field at water-air boundary

2021 ◽  
Vol 1 (395) ◽  
pp. 155-161
Author(s):  
S. Zenchenko ◽  
Keyword(s):  
Surface Layer ◽  
Temperature Field ◽  
Water Surface ◽  
Thermal Conditions ◽  
Simulation Data ◽  
Temperature Variations ◽  
Low Intensity ◽  
Water Surface Temperature ◽  
Different Temperatures ◽  
Qualitative Changes

Object and purpose of research. This paper discusses surface layer at water-air boundary. The purpose of this work to investigate, in controllable conditions, the dynamics of surface layer properties depending on temperature variations. Materials and methods. Contact multi-channel tools for temperature and humidity control, as well as infrared tools for water surface temperature monitoring. Simulation of different thermal conditions at water-air boundary and low-intensity hydrophysical disturbances on the free surface. Main results. The study yielded simulation data and experimental confirmation of humidity fluctuations in the surface layer at different temperatures at water-air boundary in the conditions of low-intensity disturbances. Conclusion. This study yielded the data on qualitative changes in surface layer humidity based on the calculations as per simultaneously measured temperatures of water in the surface layer and near water-air boundary.

Analysis and Modelling of Temperature at Lake’s Water – Atmosphere Interface

2021 ◽  
Author(s):  
Vassilis Z. Antonopoulos ◽  
Soultana K. Gianniou
Keyword(s):  
Heat Transfer ◽  
Energy Balance ◽  
Surface Temperature ◽  
Water Surface ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Net Radiation ◽  
Water Surface Temperature ◽  
Simulation Results ◽  
Input Variables

Abstract The knowledge of micrometeorological conditions on water surface of impoundments is crucial for the better modeling of the temperature and water quality parameters distribution in the water body and against the climatic changes. Water temperature distribution is an important factor that affects most physical, chemical and biological processes and reactions occurring in lakes. In this work, different processes of water surface temperature of lake’s estimation based on the energy balance method are considered. The daily meteorological data and the simulation results of energy balance components from an integrated heat transfer model for two complete years as well as the lake’s characteristics for Vegoritis lake in northern Greece were used is this analysis.The simulation results of energy balance components from a heat transfer model are considered as the reference and more accurate procedure to estimate water surface temperature. These results are used to compare the other processes. The examined processes include a) models of heat storage changes in relationship to net radiation (Qt(Rn) values, b) net radiation estimation with different approaches, as the process of Slob’s equation with adjusted coefficients to lake data, and c) ANNs models with different architecture and input variables. The results show that the model of heat balance describes the water surface temperature with high accuracy (r2=0.916, RMSE=2.422oC). The ANN(5,6,1) model in which Tsw(i-1) is incorporated in the input variables was considered the better of all other ANN structures (r2=0.995, RMSE=0.490oC). The use of different approaches for simulating net radiation (Rn) and Qt(Rn) in the equation of water surface temperature gives results with lower accuracy.

FEM Modeling and Validation of the Temperature Field in the Plasma Arc Bending of Laminated Clad Metal Sheets

2012 ◽  
Vol 602-604 ◽  
pp. 468-471
Author(s):  
Wen Qing Song ◽  
Jing Fu Chai ◽  
Wen Ji Xu
Keyword(s):  
Temperature Field ◽  
Thermal Stress ◽  
Partial Melting ◽  
Energy Input ◽  
Mechanical Force ◽  
Plasma Arc ◽  
Fem Modeling ◽  
Temperature Variations ◽  
Preheating Temperature ◽  
Metal Sheets

Plasma arc bending of laminated clad metal sheets (LCMS) is a newly developed technique that produces deformation in the LCMS by thermal stress instead of external mechanical force. Since the temperature field leads to the thermal stress, a FEM mode was developed to study the temperature variations in the plasma arc bending of the LCMS which was validated robustness by the experiments. The results show that the temperature variations of the LCMS include the preheating, temperature dramatically changing and cooling stages. The lowest temperature is in the inlet whereas the highest temperature is in the outlet along the heating line. It needs to regulate the energy input of the plasma arc to avoid the possible partial melting of the LCMS.

scholarly journals Surface Heat Budget estimation for Laurance Lake, US

2021 ◽  
Vol 877 (1) ◽  
pp. 012005
Author(s):  
Dahlia S. Abed-Zaid ◽  
Hussein A. M. Al-Zubaidi
Keyword(s):  
Surface Temperature ◽  
Water Surface ◽  
Heat Budget ◽  
Meteorological Data ◽  
Longwave Radiation ◽  
Atmospheric Conditions ◽  
Large Lakes ◽  
Water Surface Temperature ◽  
Maximum Water ◽  
The Many

Abstract Estimating heat budget factors are important to understand the many physical processes of large lakes and their reaction to the atmosphere. Some of these components are affected by water temperature, while the other depends on atmospheric conditions. This paper estimates the total heat flux for Lawrence lake via a code developed in MATLAB environment. The code can deal with different time resolutions if the lake water surface temperature data were at different time resolutions from the meteorological data. Results showed that solar energy peaks at 842 Watt/m2 at 540 Julian day, which is very normal for a sunny summer day, while the longwave radiation has 204 Watt/m2 as a min value. The back radiation did not make any reaction for the variation, but it revealed a small gradient. Furthermore, evaporation recorded - 67 Watt/m2 as a minimum value at 659 Julian day and 360 Watt/m2 as a maximum value at 578.43 Julian day close to the maximum water surface temperature event.

Modeling Of Thermophysical Processes In The Case Of Surface Modifying Of Metal During Induction Treatment

2017 ◽  
Vol 12 (1) ◽  
pp. 91-96
Author(s):  
Vladimir Popov ◽  
Vladimir Shchukin
Keyword(s):  
Numerical Simulation ◽  
Electromagnetic Field ◽  
Surface Layer ◽  
Temperature Field ◽  
High Frequency ◽  
Induction Treatment ◽  
High Frequency Electromagnetic Field ◽  
Modes Of Processing

Process of modifying of the surface layer of metals under influence of high-frequency electromagnetic field was considered using numerical simulation. The temperature field and the size of modified region were determined at various modes of processing.

scholarly journals Acclimation temperature affects thermal reaction norms for energy reserves in Drosophila

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Peter Klepsatel ◽  
Thirnahalli Nagaraj Girish ◽  
Martina Gáliková
Keyword(s):  
Thermal Conditions ◽  
Thermal Reaction ◽  
Reaction Norms ◽  
Temperate Climate ◽  
Acclimation Temperature ◽  
Energy Reserves ◽  
Optimal Temperature ◽  
Tropical Zone ◽  
Energy Stores ◽  
Different Temperatures

AbstractOrganisms have evolved various physiological mechanisms to cope with unfavourable environmental conditions. The ability to tolerate non-optimal thermal conditions can be substantially improved by acclimation. In this study, we examined how an early-life acclimation to different temperatures (19 °C, 25 °C and 29 °C) influences thermal reaction norms for energy stores in Drosophila adults. Our results show that acclimation temperature has a significant effect on the amount of stored fat and glycogen (and their relative changes) and the optimal temperature for their accumulation. Individuals acclimated to 19 °C had, on average, more energy reserves than flies that were initially maintained at 25 °C or 29 °C. In addition, acclimation caused a shift in optimal temperature for energy stores towards acclimation temperature. We also detected significant population differences in this response. The effect of acclimation on the optimal temperature for energy stores was more pronounced in flies from the temperate climate zone (Slovakia) than in individuals from the tropical zone (India). Overall, we found that the acclimation effect was stronger after acclimation to low (19 °C) than to high (29 °C) temperature. The observed sensitivity of thermal reaction norms for energy reserves to acclimation temperature can have important consequences for surviving periods of food scarcity, especially at suboptimal temperatures.

scholarly journals A Study Surface Layer and Hardness Produced by Induction Hardened S45C Steel

2014 ◽  
Vol 664 ◽  
pp. 43-47 ◽  
Author(s):  
Alain Kusmoko ◽  
Rosfian Arsyah Dahar ◽  
Hui Jun Li ◽  
Syamsul Hadi
Keyword(s):  
Surface Layer ◽  
Internal Stress ◽  
Induction Heating ◽  
Retained Austenite ◽  
Surface Hardness ◽  
Case Depth ◽  
Chemical Compositions ◽  
Different Temperatures ◽  
Significant Case ◽  
Cooling Speed

A cylinder of Carbon Steel S45C with a ferrite and pearlite structure was analysed to improve the hardness and surface layer as well as the toughness. Accordingly, it is important to undertake a heat treatment process for the hardness and surface layer of this steel. The heat teatment process was carried out using induction heating with five different temperatures of 800°C, 900°C, 1000°C, 1100°C and 1200 °C followed by water quenching with certain cooling speed. The chemical compositions and microstructures of these samples were characterized by spectrometer and optical microscopy. The microhardness of the samples was measured and the surface treatment of the samples was examined using an induction heating furnace. The results showed significant case depth and surface hardness as well as microstructure with martensite and retained austenite that is hard and brittle because of internal stress. Further, to reduce the amount of retained austenite and internal stress, it is necessary to carry out tempering of 300°C, 500°C and 700°C in order to produce toughness of the steel with slightly reduce in hardness.

Anatomical Changes to the wood of Mimosa Ophthalmocentra and Mimosa Tenuiflora when charred at different temperatures

IAWA Journal ◽  
2010 ◽  
Vol 31 (3) ◽  
pp. 333-351 ◽  
Author(s):  
Claudia Luizon Dias Leme ◽  
Caroline Cartwright ◽  
Peter Gasson
Keyword(s):  
Moisture Content ◽  
Wood Density ◽  
Anatomical Structure ◽  
Northeast Brazil ◽  
Axial Parenchyma ◽  
Anatomical Changes ◽  
Different Temperatures ◽  
Qualitative Changes ◽  
Mimosa Tenuiflora

Wood retains most of its qualitative features when charred, but the dimensions and appearance of the cells change in various ways. Wood density, anatomical structure, moisture content, duration and temperature all influence wood behaviour when charred. This paper explores the qualitative changes that take place in the wood of Mimosa ophthalmocentra and M. tenuiflora when charred artificially at temperatures of 400, 600 and 800 °C and compares them with charcoal produced in a traditional temporary kiln in northeast Brazil. Our findings can be applied to interpreting the conditions in which charcoal has been produced, and document what happens qualitatively to the vessels, fibres, axial parenchyma and rays in very dense Mimosa wood (>1.00). The observations are specific to these two species.

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