scholarly journals Production and Evaluation of Agricultural Biodegradable Mulch through Heat and Moisture Distribution in Soil

2021 ◽  
Author(s):  
Mohammad SHAHABİ ◽  
Mehdi KHOJASTEHPOUR ◽  
Hassan SADRNİA
Keyword(s):  
Moisture Distribution ◽  
Biodegradable Mulch ◽  
Heat And Moisture

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.

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.

Time-Fractional Hygrothermoelastic Problem for a Sphere Subjected to Heat and Moisture Flux

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Xue-Yang Zhang ◽  
Yi Peng ◽  
Xian-Fang Li
Keyword(s):  
Heat Conduction ◽  
Fractional Order ◽  
Integral Transform ◽  
Moisture Diffusion ◽  
Moisture Flux ◽  
Moisture Distribution ◽  
Order Derivative ◽  
Transform Method ◽  
Stress Components ◽  
Heat And Moisture

In this paper, a non-Fourier model of heat conduction and moisture diffusion coupling is proposed. We study a hygrothermal elastic problem within the framework of time-fractional calculus theory for a centrally symmetric sphere subjected to physical heat and moisture flux at its surface. Analytic expressions for transient response of temperature change, moisture distribution, displacement, and stress components in the sphere are obtained for heat/moisture flux pulse and constant heat/moisture flux at the sphere's surface, respectively, by using the integral transform method. Numerical results are calculated and the effects of fractional order on temperature field, moisture distribution, and hygrothermal stress components are illustrated graphically. Subdiffusive and super-diffusive transport coupling behavior as well as wave-like behavior are shown. When fractional-order derivative reduces to first-order derivative, the usual heat and moisture coupling is recovered, which obeys Fourier heat conduction and Fick's moisture diffusion.

Numerical Modelling of Simultaneous Heat and Moisture Transport in Fire Protective Suits Under Flash Fire Exposure and Evaluation of Second Degree Burn Time

2022 ◽  
Author(s):  
Bhavna Rajput ◽  
Ritambhara Dubey ◽  
Bahni Ray ◽  
Apurba Das ◽  
Prabal Talukdar
Keyword(s):  
Moisture Transport ◽  
Air Gap ◽  
Moisture Distribution ◽  
Transfer Model ◽  
Degree Burn ◽  
Flash Fire ◽  
Heat And Moisture Transport ◽  
In Fire ◽  
Heat And Moisture ◽  
Second Degree

Abstract An improved numerical model is developed for coupled heat and moisture transport in fire protective suit exposed to flash fire. This model is combined with Pennes' bio-heat transfer model and subsequently, second-degree burn time is estimated using Henriques' burn integral. Natural convection is considered inside the air gap present between the multilayer clothing ensemble and the skin. Comparisons of temperature and moisture distribution within the multilayer clothing, air gap, and the skin during the exposure are presented considering combined heat and moisture transport and only heat transport. Effect of moisture transport on the protective performance of the fire protective suit is shown. Impact of both horizontal and vertical air gap orientations on second-degree burn time is studied. Effect of temperature-dependent thermo-physical properties, relative humidity, fiber regain, different exposure conditions and fabric combinations for the fire protective suits on burn time is analyzed.

CALCULATION OF HEAT AND MOISTURE DISTRIBUTION IN THE POROUS MEDIA LAYER

2007 ◽  
Vol 12 (1) ◽  
pp. 91-100 ◽  
Author(s):  
Harijs Kalis ◽  
Ilmars Kangro
Keyword(s):  
Differential Equations ◽  
Transfer Problem ◽  
Initial Boundary ◽  
Initial Boundary Value Problem ◽  
Rate Of Change ◽  
Moisture Distribution ◽  
Initial Boundary Value ◽  
Volume Method ◽  
Heat And Moisture ◽  
Media Layer

In this paper we study the problem of the diffusion of one substance through the pores of a porous material which may absorb and immobilize some of the diffusing substances with the evolution or absorption of heat. The transfer of moisture and the heat are described by the model. The system of two partial differential equations (PDEs) is derived, one equation expresses the rate of change of concentration of water vapour in the air spaces and the other the rate of change of temperature. The obtained initial‐boundary value problem is approximated by using the finite volume method. This procedure allows us to reduce the 2D transfer problem described by a system of PDEs to initial value problem for a system of ordinary differential equations (ODEs) of the first order.

The Shikani HME: A New Tracheostomy Heat and Moisture Exchanger

2020 ◽  
Vol 63 (9) ◽  
pp. 2921-2929
Author(s):  
Alan H. Shikani ◽  
Elamin M. Elamin ◽  
Andrew C. Miller
Keyword(s):  
Ex Vivo ◽  
Moisture Loss ◽  
Speaking Valve ◽  
Time Zero ◽  
In Series ◽  
Turbulent Airflow ◽  
The Difference ◽  
Loss Efficiency ◽  
Heat And Moisture ◽  
Lung Simulation

Purpose Tracheostomy patients face many adversities including loss of phonation and essential airway functions including air filtering, warming, and humidification. Heat and moisture exchangers (HMEs) facilitate humidification and filtering of inspired air. The Shikani HME (S-HME) is a novel turbulent airflow HME that may be used in-line with the Shikani Speaking Valve (SSV), allowing for uniquely preserved phonation during humidification. The aims of this study were to (a) compare the airflow resistance ( R airflow ) and humidification efficiency of the S-HME and the Mallinckrodt Tracheolife II tracheostomy HME (M-HME) when dry (time zero) and wet (after 24 hr) and (b) determine if in-line application of the S-HME with a tracheostomy speaking valve significantly increases R airflow over a tracheostomy speaking valve alone (whether SSV or Passy Muir Valve [PMV]). Method A prospective observational ex vivo study was conducted using a pneumotachometer lung simulation unit to measure airflow ( Q ) amplitude and R airflow , as indicated by a pressure drop ( P Drop ) across the device (S-HME, M-HME, SSV + S-HME, and PMV). Additionally, P Drop was studied for the S-HME and M-HME when dry at time zero (T 0 ) and after 24 hr of moisture testing (T 24 ) at Q of 0.5, 1, and 1.5 L/s. Results R airflow was significantly less for the S-HME than M-HME (T 0 and T 24 ). R airflow of the SSV + S-HME in series did not significant increase R airflow over the SSV or PMV alone. Moisture loss efficiency trended toward greater efficiency for the S-HME; however, the difference was not statistically significant. Conclusions The turbulent flow S-HME provides heat and moisture exchange with similar or greater efficacy than the widely used laminar airflow M-HME, but with significantly lower resistance. The S-HME also allows the innovative advantage of in-line use with the SSV, hence allowing concurrent humidification and phonation during application, without having to manipulate either device.

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