scholarly journals Temperature and moisture distribution in a highway in south-eastern Kazakhstan

2019 ◽  
Vol 265 ◽  
pp. 02005 ◽  
Author(s):  
Bagdat Teltayev ◽  
Elena Suppes
Keyword(s):  
Air Temperature ◽  
Moisture Distribution ◽  
Structural Elements ◽  
Moisture Variation ◽  
Special Measurement ◽  
Measurement Devices ◽  
Depth Increase ◽  
And Migration ◽  
Heat And Moisture ◽  
Air Temperature Variations

The matters of investigation for water thermal regime of pavement and subgrade structures of the highways are especially important as the moisture and temperature distribution in pavement and subgrade layers impact greatly on their deformation and strength indicators. Experimental results, which can be obtained by special measurement devices, are primary ones for establishing of peculiarities and regularities for distribution and migration of heat and moisture in the mentioned structural elements of the highways. Special measurement devices are required to obtain such experimental data. The paper shows the results for analysis of temperature and moisture variation in points of pavement and subgrade of “Almaty-Bishkek” highway. Temperature measurement has been performed by set of special sensors. Regular temperature and moisture measurement have been performed for the period from September 18, 2015 to June 2, 2016. Regularities for temperature regime variation in points of pavement for 24 hours are coordinated with air temperature variations. Amplitude of vibration for temperature is decreased with the depth increase. Moisture in subgrade points is gradually decreased with the reduction of daily average air temperature.

Technology of Heat and Moisture Regeneration for Ventilation Systems

2021 ◽  
pp. 174-222
Keyword(s):  
Silica Gel ◽  
Air Temperature ◽  
Sodium Acetate ◽  
Temperature Drop ◽  
Sodium Sulphate ◽  
Efficiency Factor ◽  
Cold Air ◽  
Temperature Efficiency ◽  
Heat And Moisture ◽  
Ventilation Systems

The chapter is focused on technology of heat and moisture regeneration for ventilation systems. In the first sub-division recent progress in adsorptive technologies for air dehumidification, heating and conditioning is analyzed. In the next sub-divisions results of original researches of authors on adsorptive heat and moisture regeneration are given. The design of adsorptive heat-moisture regenerator for ventilation systems is shown. Its operation and the results of field tests are described. The technology of regeneration of low-potential heat and moisture by composite sorbent ‘silica gel – sodium sulphate' is suggested. Experimental plots of temperature, absolute and relative humidity at the inlet and the outlet of the apparatus and between cassettes with the composite are given. Correlation of flows switch-over time, airflow rate and temperature drop is stated. The relationships temperature efficiency factor vs. dimensionless temperature drop and moisture efficiency factor vs. absolute humidity dimensionless drop are derived with fair accuracy for engineering calculation. Ability of purposeful modification of the above-mentioned characteristics within broad ranges by changing the half-cycle time, the size of the granules of the adsorbent and its amount is revealed. The mathematical model and algorithm for determining the basic parameters of adsorptive regenerator operating processes are developed. The proposed algorithm involves calculating the volume of air passed through the layer of adsorptive heat-storage material, the concentration of water in the airflow at the outlet of the regenerator, the adsorption, the heat of adsorption, the final temperature of the cold air, the air temperature after mixing the cold air from the street and the warm air in the room at the warm end of the regenerator during inflow, calculation of the final concentration of water in the flow at the cold end of the regenerator, the volume of air passing through the layer of heat-accumulating material, adsorption and heat of adsorption, the final temperature of the air at the cold end of the regenerator, the air temperature after mixing of the cold air from the street and the warm air from the room at the cold end of regenerator during outflow, determining the temperature efficiency coefficient, summarized adsorption and maximal adsorption time. The correlation of air temperatures near the warm and cold end of the regenerator, as well as the temperature efficiency factors calculated according to the proposed algorithm and obtained by experimental way is confirmed. The mathematical modeling of the processes of operation of adsorption regenerators based on composites ‘silica gel – sodium sulphate' and ‘sodium acetate' in the conditions of the typical ventilation system of residential premises is carried out. The dependences of the temperature efficiency factor vs. the time of switching air flows and the velocity of air flow, as well as the temperatures of external and internal air under stationary conditions are shown. An optimal composition of composite adsorbents is stated to be 20% of silica gel and 80% of salt, that is, sodium sulphate or sodium acetate. Due to higher value of maximal adsorption composite ‘silica gel – Na2SO4' is shown to be required in half as much as compared with ‘silica gel – CH3COONa'. The results of the research can be used in the development of energy-efficient ventilation systems and devices for residential and warehouse premises.

Analytical solution for heat and moisture diffusion in layered materials

2010 ◽  
Vol 47 (6) ◽  
pp. 595-608 ◽  
Author(s):  
Jeongwoo Lee ◽  
Ji-Tae Kim ◽  
Il-Moon Chung ◽  
Nam Won Kim
Keyword(s):  
Analytical Solutions ◽  
Numerical Solutions ◽  
Integral Transform ◽  
Moisture Diffusion ◽  
Layered Materials ◽  
Diffusion Problem ◽  
Moisture Distribution ◽  
Coupled Flow ◽  
Coupled Diffusion ◽  
Heat And Moisture

The study of heat and moisture flows in multiple layers of different materials that make up the unsaturated zone is of great importance when characterizing the behaviour of these materials. In the present paper, analytical solutions of the one-dimensional heat and moisture coupled diffusion problem for layered materials under two different sets of boundary conditions are proposed. The coupled flow of heat and moisture are assumed to follow the theory of Philip and De Vries, and the solutions are derived analytically using integral transform methods. A comparison between the analytical and numerical solutions for one example problem shows satisfactory results. Furthermore, a procedure is presented for estimating heat and moisture distribution profiles in any layered materials using the derived analytical solutions. It is expected that the proposed analytical solutions will be used effectively for preliminary analyses of coupled heat and moisture movements in unsaturated porous media.

Land surface air temperature variations over Eurasia and possible causes in the past century

2017 ◽  
Vol 38 (4) ◽  
pp. 1925-1937 ◽  
Author(s):  
Zhiyan Zuo ◽  
Song Yang ◽  
Kang Xu ◽  
Renhe Zhang ◽  
Qiong He ◽  
...  
Keyword(s):  
Air Temperature ◽  
Land Surface ◽  
Surface Air Temperature ◽  
Past Century ◽  
Temperature Variations ◽  
The Past ◽  
Air Temperature Variations

scholarly journals Northern Hemisphere Surface Air Temperature Variations: 1851–1984

1986 ◽  
Vol 25 (2) ◽  
pp. 161-179 ◽  
Author(s):  
P. D. Jones ◽  
S. C. B. Raper ◽  
R. S. Bradley ◽  
H. F. Diaz ◽  
P. M. Kellyo ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Air Temperature ◽  
Surface Air Temperature ◽  
Temperature Variations ◽  
Hemisphere Surface ◽  
Air Temperature Variations

Diffraction imaging by focusing‐defocusing: An outlook on seismic superresolution

Geophysics ◽  
2004 ◽  
Vol 69 (6) ◽  
pp. 1478-1490 ◽  
Author(s):  
V. Khaidukov ◽  
E. Landa ◽  
T. J. Moser
Keyword(s):  
Image Resolution ◽  
Correct Identification ◽  
Structural Elements ◽  
Large Area ◽  
Specular Reflections ◽  
Full Wave ◽  
Geological Discontinuities ◽  
Diffraction Imaging ◽  
And Migration ◽  
Traditional Image

Diffractions always need more advertising. It is true that conventional seismic processing and migration are usually successful in using specular reflections to estimate subsurface velocities and reconstruct the geometry and strength of continuous and pronounced reflectors. However, correct identification of geological discontinuities, such as faults, pinch‐outs, and small‐size scattering objects, is one of the main objectives of seismic interpretation. The seismic response from these structural elements is encoded in diffractions, and diffractions are essentially lost during the conventional processing/migration sequence. Hence, we advocate a diffraction‐based, data‐oriented approach to enhance image resolution—as opposed to the traditional image‐oriented techniques, which operate on the image after processing and migration. Even more: it can be shown that, at least in principle, processing of diffractions can lead to superresolution and the recovery of details smaller than the seismic wavelength. The so‐called reflection stack is capable of effectively separating diffracted and reflected energy on a prestack shot gather by focusing the reflection to a point while the diffraction remains unfocused over a large area. Muting the reflection focus and defocusing the residual wavefield result in a shot gather that contains mostly diffractions. Diffraction imaging applies the classical (isotropic) diffraction stack to these diffraction shot gathers. This focusing‐muting‐defocusing approach can successfully image faults, small‐size scattering objects, and diffracting edges. It can be implemented both in model‐independent and model‐dependent contexts. The resulting diffraction images can greatly assist the interpreter when used as a standard supplement to full‐wave images.

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