scholarly journals TRANSIENT MEASURING METHOD FOR MOISTURE DIFFUSION COEFFICIENTS : Part. 3 Experimental results

1985 ◽  
Vol 348 (0) ◽  
pp. 1-10 ◽  
Author(s):  
MASAKI NAKAO
Keyword(s):  
Diffusion Coefficients ◽  
Moisture Diffusion ◽  
Measuring Method ◽  
Experimental Results

scholarly journals Characterization of Moisture Diffusion in Cured Concrete Slabs at Early Ages

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Xiao Zhang ◽  
Hongduo Zhao
Keyword(s):  
Process Model ◽  
Model Simulation ◽  
Moisture Diffusion ◽  
Experimental Results ◽  
Concrete Slabs ◽  
Model Parameters ◽  
Early Age ◽  
Water Curing ◽  
Early Age Concrete

The objective of this paper is to investigate the characterization of moisture diffusion inside early-age concrete slabs subjected to curing. Time-dependent relative humidity (RH) distributions of three mixture proportions subjected to three different curing methods (i.e., air curing, water curing, and membrane-forming compounds curing) and sealed condition were measured for 28 days. A one-dimensional nonlinear moisture diffusion partial differential equation (PDE) based on Fick’s second law, which incorporates the effect of curing in the Dirichlet boundary condition using a concept of curing factor, is developed to simulate the diffusion process. Model parameters are calibrated by a genetic algorithm (GA). Experimental results show that the RH reducing rate inside concrete under air curing is greater than the rates under membrane-forming compound curing and water curing. It is shown that the effect of water-to-cement (w/c) ratio on self-desiccation is significant. Lower w/c ratio tends to result in larger RH reduction. RH reduction considering both effect of diffusion and self-desiccation in early-age concrete is not sensitive to w/c ratio, but to curing method. Comparison between model simulation and experimental results indicates that the improved model is able to reflect the effect of curing on moisture diffusion in early-age concrete slabs.

Search for Superconductivity under Ultra-high Pressure

1999 ◽  
Vol 13 (29n31) ◽  
pp. 3623-3625 ◽  
Author(s):  
K. Amaya ◽  
K. Shimizu ◽  
M. I. Eremets
Keyword(s):  
High Pressure ◽  
Low Temperature ◽  
Electrical Resistance ◽  
Measuring Method ◽  
Experimental Results ◽  
Molecular Systems ◽  
Ultra High Pressure ◽  
Diamond Anvil ◽  
Very Low Temperature

Techniques of producing ultra-high pressure at very low temperature and measuring method of electrical resistance and magnetization of samples confirmed in the used diamond anvil ceil (DAC) are shortly described. Experimental results on simple molecular systems such as iodine, sulfur, oxygen and organic iodanil are reviewed as typical example of pressure induced superconductivity.

Prediction of Trifluralin Diffusion Coefficients

Weed Science ◽  
1973 ◽  
Vol 21 (5) ◽  
pp. 485-489 ◽  
Author(s):  
L. E. Bode ◽  
C. L. Day ◽  
M. R. Gebhardt ◽  
C. E. Goering
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Diffusion Coefficients ◽  
Moisture Diffusion ◽  
Soil Parameters ◽  
Void Space ◽  
Exponential Relationship ◽  
Maximum Value ◽  
Soil Temperatures ◽  
Dry Soil

In the range of 4.4 to 49 C, there is an exponential relationship between temperature and trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) diffusion coefficients. Diffusion is low in air-dry soil for all temperatures. It increases to a maximum value when the soil has between 8 and 15% w/w soil moisture content and then decreases steadily as moisture content increases. When the air-filled fraction of soil void space is reduced below approximately 40% v/v by either compression or addition of moisture, diffusion begins to decrease. An equation was developed to predict trifluralin diffusion coefficients from a factorial experiment with seven soil moisture contents, five soil temperatures, and two bulk densities. Diffusion coefficients range from 3.8 X 10-11 cm2/sec to 2.8 X 10-6 cm2/sec. Fifteen terms are required in the prediction model to describe accurately the response surface of trifluralin diffusion coefficients. With the equation it is possible to predict trifluralin diffusion coefficients for any combination of measured soil parameters as long as they are represented by the range of the variables used in the experiment.

scholarly journals The Ni-Al-Hf Multiphase Diffusion

2016 ◽  
Vol 61 (2) ◽  
pp. 587-592 ◽  
Author(s):  
J. Romanowska ◽  
B. Wierzba ◽  
J. Markowski ◽  
M. Zagula-Yavorska ◽  
J. Sieniawski
Keyword(s):  
Diffusion Coefficients ◽  
Thermodynamic Data ◽  
Pure Nickel ◽  
Experimental Results ◽  
Nickel Aluminum ◽  
Aluminide Coatings ◽  
Multiphase Diffusion

Abstract The generalized Darken method was applied to simulate the diffusion between γ-Ni| γ’-Ni3Al and γ’-Ni3Al|β-NiAl interfaces. The results of calculations were compared with the experimental concentration’s profiles of nickel, aluminum and hafnium in aluminide and hafnium doped aluminide coatings deposited by the CVD and PVD methods on pure nickel. The method deals with the Wagner’s integral diffusion coefficients and thermodynamic data - activities of components. The experimental results agree with the simulated ones.

Computer Aided Identification of the Moisture Transport Parameters in Spruce Wood

Holzforschung ◽  
2003 ◽  
Vol 57 (5) ◽  
pp. 533-538 ◽  
Author(s):  
P. Koc ◽  
M. Houka ◽  
B. Štok
Keyword(s):  
Inverse Problem ◽  
Moisture Content ◽  
Diffusion Coefficients ◽  
Moisture Diffusion ◽  
Transport Parameters ◽  
Moisture Flow ◽  
Identification Method ◽  
Three Samples ◽  
Computer Aided

Summary An inverse identification method for characterization of wood sorptive properties is presented. The method relies on a computer simulation of a real experiment, in our case a desorption experiment, where spruce heartwood samples were dried from 27% to 8% moisture content. Three samples, distinguished by the respective moisture flow pattern through the specimen, were investigated. A computer aided material characterization using the so-called inverse problem identification method was performed on the measurements. The solution of the specified inverse problem enabled us to estimate the moisture diffusion coefficients of wood and to determine the moisture content field in the sample simultaneously. The method is first verified on two simple cases of uniaxial moisture flow, and then is used to characterize the diffusion coefficients on a biaxial moisture flow sample. In the latter case some salient features of the proposed method are exhibited.

A Temperature Measurement Method Based on RC Discharge Circuit Using Platinum Resistance

2014 ◽  
Vol 1037 ◽  
pp. 143-146
Author(s):  
Xiao Qiong Zuo ◽  
Jian Ping Jia ◽  
Juan Lei
Keyword(s):  
Temperature Measurement ◽  
Measurement Method ◽  
Low Cost ◽  
Measuring Method ◽  
Experimental Results ◽  
Discharge Circuit ◽  
Platinum Resistance ◽  
Discharge Time ◽  
Temperature Resistance ◽  
Temperature Measuring

This paper proposes a temperature measuring method of low cost and stable precision based on platinum resistance. RC discharge circuit is composed of platinum resistor and fixed capacitor,the discharge time of fixed capacitance in the circuit is used for calculating the platinum resistance temperature resistance. The experimental results show that this is a simple and low cost method .

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