A Combination of Spatial Domain Filters to Detect Surface Ocean Current from Multi-Sensor Remote Sensing Data

This research investigates the applicability of combining spatial filter’s algorithm to extract surface ocean current. Accordingly, the raster filters were tested on 80–13,505 daily images to detect Kuroshio Current (KC) on weekly, seasonal, and climatological scales. The selected raster filters are convolution, Laplacian, north gradient, sharpening, min/max, histogram equalization, standard deviation, and natural break. In addition, conventional data set of sea surface currents, sea surface temperature (SST), sea surface height (SSH), and non-conventional data such as total heat flux, surface density (SSD), and salinity (SSS) were employed. Moreover, controversial data on ocean color are included because very few studies revealed that chlorophyll-α is a proxy to SST in the summer to extract KC. Interestingly, the performance of filters is uniform and thriving for seasonal and on a climatological scale only by combining the algorithms. In contrast, the typical scenario of identifying Kuroshio signatures using an individual filter and by designating a value spectrum is inapplicable for specific seasons and data set. Furthermore, the KC’s centerlines computed from SST, SSH, total heat flux, SSS, SSD, and chlorophyll-α correlate with sea surface currents. Deviations are observed in the various segments of Kuroshio’s centerline extracted from heat flux, chlorophyll-α, and SSS flowing across Tokara Strait from northeast Taiwan to the south of Japan.

Land-sea Thermal Contrast in Relation With Summer Monsoon Onset Over the Chao Phraya River Basin

An earlier onset of the Southeast Asian summer monsoon (SAM) was observed over the Chao Phraya River basin in Thailand using Thai Meteorological Department (TMD)-derived high-resolution merged rainfall from 1981 to 2016. As the SAM is precipitous, its variability depends on many local and global factors, such as thermal conditions over the Bay of Bengal (BoB) and Tibetan Plateau (TbT). Despite tremendous studies in the past, the role of thermal heat contrast over SAM is still not fully understood. Using the observation and reanalysis datasets, it was found that the absolute value of total heat over the BoB was higher. However, the interannual variability in total heat is higher over the TbT. Significant changes in surface temperature (±1.5°C), air thickness (±20 meters) and geopotential height found over the TbT were associated with early (late) SAM onset. The results also suggested that the significant changes in air thickness were influenced by the surface temperature difference over the TbT, and the changes in the integrated apparent heat source and integrated apparent moisture sink were up to ± 100 Wm−2, which resulted in stronger (weaker) convective activities over the BoB and mainland of the Indochina Peninsula during early (late) SAM onset. At the intraseasonal timescale, the instance MJO found over the Indian Ocean and Western Hemisphere at 4 to 10 days span during early SAM onset. An opposite scenario is found for a late SAM onset years with MJO location over Western Pacific and Maritime continent.

MATHEMATICAL MODELING OF THERMAL EFFICIENCY OF BUILDING EN-VELOPE OF MULTI-STOREY BUILDINGS WITH ACCOUNT OF INDIVIDUAL INSULATION

At present, the problem of general thermal modernization of building envelopes is given much attention both at the level of scientists and consumers. This is one of the effective ways to reduce natural gas consumption, reduce the negative impact on the environment, maintain and improve comfortable indoor conditions. Over the last decade, the population has rapidly begun to insulate their homes in order to raise the indoor air temperature to a comfortable level in the multi-storey residential sector. Due to insufficient attention of the authorities in the housing and communal sector, the lack of scientific research and widespread public awareness, there is a massive thermal insulation of building by residents of multi-store buildings within their own apartments. But the study of thermal processes that occur in individual thermal insulation of enclosing structures is currently not fully completed. Therefore, in the context of significant increases in gas and electricity prices, this problem is relevant. In the study was carried out mathematical modeling of a fragment of a partially insulated wall of an enclosing structure with determination of heat flux by solving a three-dimensional differential equation of thermal conductivity with boundary conditions of II, III and IV kind and distribution of characteristics of building structures and insulation. These results can be used in the analysis of the efficiency of insulation of the building taking into account the fragmentary insulation and of comparison with systemic thermal modernization. As a result of modeling, the three-dimensional temperature fields of wall surfaces, are determined, there are additional heat fluxes (thermal bridges), which are not considered in the simplified one-dimensional calculation. In one-dimensional calculation, the heat flux from the wall is reduced by 2.43 times during insulation. Taking into account the total heat flow from the side surfaces near the window (thermal bridges) and system insulation - by 1.75 times. With fragmentary insulation and considering the total heat flux from the side surfaces near the window - by 1.6 times. The next stage of calculations is the determination of the actual air temperatures in the premises of a multi-storey building considering the actual condition of enclosing structures and heating systems, heaters, mode parameters of the coolant and outdoor air parameters. The methods and means of this analysis can take into account the final data of heat loss adjustment after the mathematical modeling presented in this paper. In consequence, the results will be taken into account in the projects of thermal modernization of buildings, reconstruction of heating systems, rational placement of sources, selection of equipment and regulation of devices.

FEATURES OF SPATIAL-TIME VARIABILITY OF TOTAL TURBULENT HEAT FLUXES AT THE OCEAN-ATMOSPHERE INTERFACE IN THE ATLANTIC

The features of the spatial distribution of climate values and the coefficients of linear trends of total tur-bulent heat fluxes are revealed, based on NCEP/NCAR reanalysis data for 1950–2020 for the Atlantic Ocean. Variability of total turbulent heat fluxes is investigated on scales of more than 10 and more than 30 years. It is shown that the trends of average annual total heat fluxes significant at 95% level in most part of the Atlantic Ocean area are negative (except for the western parts of anticyclonic gyres and area of arctic sea ice edge). It is confirmed that the maxima of the low-frequency variability of the total heat fluxes correspond to important energy-active zones of the Atlantic, they are North Atlantic deep-water mass formation region, ice edge zone in the north of the North Atlantic and the Atlantic sector of the Arc-tic Ocean.

Effect of Pin Shape on Thermal History of Aluminum-Steel Friction Stir Welded Joint: Computational Fluid Dynamic Modeling and Validation

This article studied the effects of pin angle on heat generation and temperature distribution during friction stir welding (FSW) of AA1100 aluminum alloy and St-14 low carbon steel. A validated computational fluid dynamics (CFD) model was implemented to simulate the FSW process. Scanning electron microscopy (SEM) was employed in order to investigate internal materials’ flow. Simulation results revealed that the mechanical work on the joint line increased with the pin angle and larger stir zone forms. The simulation results show that in the angled pin tool, more than 26% of the total heat is produced by the pin. Meanwhile, in other cases, the total heat produced by the pin was near 15% of the total generated heat. The thermo-mechanical cycle in the steel zone increased, and consequently, mechanical interlock between base metals increased. The simulation output demonstrated that the frictional heat generation with a tool without a pin angle is higher than an angled pin. The calculation result also shows that the maximum heat was generated on the steel side.

THE INFLUENCE OF ENCLOSURE ON BURNING CHARACTERISTICS OF OSB FURNISHINGS

This paper presents a series of full-scale tests conducted with office furniture made from OSB boards. Ignition source (30 kW gas burner) position and enclosure effects, free burn vs. ISO 9705 room, were evaluated from the perspective of instantaneous (HRR) and total heat (THR) released by the fuel packages. It was found that both of the evaluated factors have impact primarily on HRR – the peak ranging from 874 kW to 1 154 kW was delayed by approx. 50 to 60 s in the free-burn experiments; the THR remained relatively consistent at approx. 875 ± 30 MJ, meaning that in the observed period very similar amounts of fuel were burned. The thermal feedback within the enclosure seemed to be partially counteracted by the lack of oxygen, resulting in slightly higher HRR in free-burn test following the first peak. The findings of the research are applicable to fire hazard prediction by fire modelling.

A novel heat generation acquisition method of cylindrical battery based on core and surface temperature measurements

Heat generation measurements of the lithium-ion battery are crucial for the design of the battery thermal management system. Most previous work uses the accelerating rate calorimeter (ARC) to test heat generation of batteries. However, utilizing ARC can only obtain heat generation of the battery operating under the adiabatic condition, deviating from common operation scenarios with heat dissipation. Besides, using ARC is difficult to measure heat generation of the high-rate operating battery because the battery temperature easily exceeds the maximum safety limit. To address these problems, we propose a novel method to obtain heat generation of cylindrical battery based on core and surface temperature measurements and select the 21700 cylindrical battery as the research object. Based on the method, total heat generation at 1C discharge rate under the natural convection air cooling condition in the environmental chamber is about 3.2 kJ, and the average heat generation rate is about 0.9 W. While these two results measured by ARC are about 2.2 kJ and 0.6 W. This gap also reflects that different battery temperature histories have significant impacts on heat generation. In addition, using our approach, total heat generation at 2C discharge rate measured in the environmental chamber is about 5.0 kJ, with the average heat generation rate being about 2.8 W. Heat generation results obtained by our method are approximate to the actual battery operation and have advantages in future applications.

Heat capacity of dispersed rocks

Protection of automobile roads from negative cryogenic processes is a current issue to which significant attention is devoted in both scientific and engineering communities. In many cases important for practice, the the thermal factor determines the reliability and security of the use of the road in the cryolithic zone. The heat capacity of dispersed rocks is among the most important indicators of the physical properties determining the intensity of thermal processes in the road surfaces and road foundations. The precision of determination of the total heat capacity of the rocks in thawed and frozen state largely determines the precision of the forecast of the thermal regime of roads in the cryolithic zone. A complex assessment of the impact of ice content of the dispersed rocks on the value of total heat capacity was done. 2D and 3D charts which allow to assess the possible range of change in the heat capacity of the dispersed rocks in thawed and frozen state, in both a wide range and in the typical range of values, were produced. Among the main criteria determining the extent of the seasonal freezing and thawing of the soils of the active layer is the Stefan number, a dimensionless criterion. An overall assessment of the impact of ice content on the ground (rock) foundations of the roads and of the air temperature in the warm period of the year on the quantitative values of the Stefan number was done. Charts allowing to determine in both a wide and typical range the changes of values of the Stefan numbers, permitting to assess the possible range of changes of the Stefan number, were made. It was determined, in particular, that for the typical dispersed rocks of the road foundations in the cryolithic zone the range of change in the Stefan numbers is 2.1-6.5.