scholarly journals AERATED CONCRETE MICROWAVE REFLECTION AND TRANSMISSION PROPERTIES IN A WET ENVIRONMENT

2017 ◽  
Vol 3 ◽  
pp. 145
Author(s):  
Tarmo Koppel ◽  
Inese Vilcane ◽  
Viktor Mironov ◽  
Andrei Shiskin ◽  
Sanita Rubene ◽  
...  
Keyword(s):  
Water Content ◽  
Transmission Loss ◽  
Base Station ◽  
Microwave Propagation ◽  
Reflection And Transmission ◽  
Excess Water ◽  
Base Station Antennas ◽  
Mobile Phone Base Station ◽  
Aerated Concrete ◽  
Wetting Process

Excess water content within the building material could greatly alter the interaction of the microwave with the material. In this study aerated concrete (AEROC) block walls (60x60cm) were investigated for their microwave (2.4 GHz) properties under wetting conditions. The spray wetting of the wall was conducted to simulate the environmental processes such as raining or water damage. 50ml/m² water dosage was applied on the surface of the concrete 21 times in 1 min intervals. The results show a noticeable decrease in microwave penetration power through the material after the sample gets enriched with water. As the water content on the surface of the material rises, so does the transmission loss. During the different water content of the aerated concrete, the reflection loss varied from -15.04 dB (dry wall) to -5.03 dB (wet wall’s surface). The transmission loss continues to rise during the entire length of the experiment, from -4.5 dB as a dry sample to -8.3 dB after 441 ml (1035 ml/m² during 23 min) of sprayed water. The variation of reflected microwave power was approximately ten times, which is quite a significant indicator of alteration of microwave propagation. The results demonstrate wetting process as an considerable factor in assessing microwave propagation in near the sources, such as mobile phone base station antennas, industrial microwave heaters and ovens etc.

Evaluation of Moisture Content in Concrete with Microwave

2006 ◽  
Vol 312 ◽  
pp. 311-318 ◽  
Author(s):  
Xiao Ming Wang ◽  
Yinghao Teo ◽  
Wing K. Chiu ◽  
Greg Foliente
Keyword(s):  
Moisture Content ◽  
Water Content ◽  
Condition Monitoring ◽  
Reflection And Transmission Coefficients ◽  
Physical Change ◽  
Microwave Propagation ◽  
Reflection And Transmission ◽  
One Dimensional ◽  
Transmission Coefficients ◽  
Permittivity And Permeability

Generally, any chemical or physical change in a material may cause variation in its permittivity and permeability. The propagation of microwave through the material can be affected by these variation in properties. The analysis of microwave propagation through materials may therefore provide a means for condition monitoring. This paper utilizes a one-dimensional scenario, demonstrating the feasibility to link measurable reflection and transmission coefficients of microwave to concrete permittivity and permeability, which are essentially associated with water content in concrete. As a result, water content can then be monitored through the measurement of these coefficients. The study also demonstrates the feasibility of using the same technique to estimate the thickness of the concrete that microwave propagates through.

Analysis of Antenna Types Performance in Mobile Phone Base Station

2017 ◽  
Author(s):  
Saba Fadhel Jaf ◽  
Muhamed Fadhel Jaf ◽  
Niyaz Fadhel Jaf
Keyword(s):  
Mobile Phone ◽  
Base Station ◽  
Mobile Phone Base Station

Palmer Amaranth (Amaranthus palmeri) Competition for Water in Cotton

Weed Science ◽  
2015 ◽  
Vol 63 (4) ◽  
pp. 928-935 ◽  
Author(s):  
Sarah T. Berger ◽  
Jason A. Ferrell ◽  
Diane L. Rowland ◽  
Theodore M. Webster
Keyword(s):  
Water Content ◽  
Relative Water Content ◽  
Yield Loss ◽  
Linear Trend ◽  
Palmer Amaranth ◽  
Cotton Production ◽  
Excess Water ◽  
Relative Water ◽  
Competition For Light ◽  
Daily Water

Palmer amaranth is a troublesome weed in cotton production. Yield losses of 65% have been reported from season-long Palmer amaranth competition with cotton. To determine whether water is a factor in this system, experiments were conduced in 2011, 2012, and 2013 in Citra, FL, and in Tifton, GA. In 2011, infrequent rainfall lead to drought stress. The presence of Palmer amaranth resulted in decreased soil relative water content up to 1 m in depth. Cotton stomatal conductance (gs) was reduced up to 1.8 m from a Palmer amaranth plant. In 2012 and 2013 higher than average rainfall resulted in excess water throughout the growing season. In this situation, no differences were found in soil relative water content or cottongsas a function of proximity to Palmer amaranth. A positive linear trend was found in cotton photosynthesis and yield; each parameter increased as distance from Palmer amaranth increased. Even in these well-watered conditions, daily water use of Palmer amaranth was considerably higher than that of cotton, at 1.2 and 0.49 g H20 cm−2d−1, respectively. Although Palmer amaranth removed more water from the soil profile, rainfall was adequate to replenish the profile in 2 of the 3 yr of this study. However, yield loss due to Palmer amaranth was still observed despite no change ings, indicating other factors, such as competition for light or response to neighboring plants during development, are driving yield loss.

Whole-body average SAR measurement using flat phantoms for radio base station antennas and its applicability to adult and child human models

2018 ◽  
Vol 74 (1-2) ◽  
pp. 93-102 ◽  
Author(s):  
Takahiro Iyama ◽  
Teruo Onishi ◽  
Kensuke Sasaki ◽  
Tomoaki Nagaoka ◽  
Lira Hamada ◽  
...  
Keyword(s):  
Base Station ◽  
Whole Body ◽  
Human Models ◽  
Base Station Antennas
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