scholarly journals Moisture Content Measurements of Green Roof Substrates Using Two Dielectric Sensors

2013 ◽  
Vol 23 (2) ◽  
pp. 177-186 ◽  
Author(s):  
George Kargas ◽  
Nikolaos Ntoulas ◽  
Panayiotis A. Nektarios
Keyword(s):  
Moisture Content ◽  
Frequency Domain ◽  
Time Domain ◽  
Green Roof ◽  
Dielectric Sensor ◽  
Substrate Moisture ◽  
Moisture Content Determination ◽  
Actual Substrate ◽  
Dielectric Sensors

Little is known about the accuracy of soil moisture dielectric sensors in coarse-textured root zones and green roof substrates. In the present study, the accuracy of two dielectric sensors of different technologies (frequency domain and time domain dielectric sensor) in measuring moisture content was investigated in six coarse-textured green roof substrates. Calibration equations were developed for both sensors, and the effect of electrical conductivity (EC) on substrate moisture content calculation was determined. It was found that for frequency domain sensor the relationship between dielectric permittivity square root () and actual substrate moisture content (θm) was strongly linear for all tested substrates. However, for each substrate a distinct specific calibration equation of was required. The correlation between substrate permittivity and EC was linear for frequency domain sensor for all moisture levels (0% to 35%). In the case of time domain sensor, each green roof substrate was also described from a different calibration curve between actual substrate moisture content and period of time that was recorded by the device. It was found that their relationship was quadratic for all substrates. In addition, time domain sensor output responded in a quadratic manner to increasing levels of EC. This response was found to interact with actual substrate moisture content as well. It was concluded that the most reliable results for moisture content determination of the coarse-textured green roof substrates were obtained by substrate-specific calibration curves for both dielectric sensors.

scholarly journals Influence of Temperature and Moisture Content on Thermal Performance of Green Roof Media

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2421
Author(s):  
Bohan Shao ◽  
Caterina Valeo ◽  
Phalguni Mukhopadhyaya ◽  
Jianxun He
Keyword(s):  
Thermal Conductivity ◽  
Moisture Content ◽  
Green Roof ◽  
Green Roofs ◽  
Power Functions ◽  
Thick Substrate ◽  
Different Temperatures ◽  
Test Cells ◽  
Substrate Moisture ◽  
Phase Transition Zone

The influence of moisture content on substrate thermal conductivity at different temperatures was investigated for four different commercially available substrates for green roofs. In the unfrozen state, as moisture content increased, thermal conductivity increased linearly. In the phase transition zone between +5 and −10 °C, as temperature decreased, thermal conductivity increased sharply during the transition from water to ice. When the substrate was frozen, thermal conductivity varied exponentially with substrate moisture content prior to freezing. Power functions were found between thermal conductivity and temperature. Two equally sized, green roof test cells were constructed and tested to compare various roof configurations including a bare roof, varying media thickness for a green roof, and vegetation. The results show that compared with the bare roof, there is a 75% reduction in the interior temperature’s amplitude for the green roof with 150 mm thick substrate. When a sedum mat was added, there was a 20% reduction in the amplitude of the inner temperature as compared with the cell without a sedum mat.

Determination of readiness for laying based on material moisture, corresponding relative humidity, and water release

2020 ◽  
Vol 62 (10) ◽  
pp. 1033-1040
Author(s):  
Christoph Strangfeld ◽  
Sabine Kruschwitz
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Embedded Sensors ◽  
Residual Water ◽  
Floor Covering ◽  
Water Release ◽  
Content Determination ◽  
Two Samples ◽  
Moisture Content Determination

Abstract The moisture content of the subfloor has to be determined before installation to avoid damage to the floor covering. Only if readiness for layering is reached, can an installation without damage be expected in all cases. In general, three approaches exist to measure residual water content: determination of moisture content, determination of water release, or determination of the corresponding relative humidity. All three approaches are tested under laboratory conditions at eight screed types including two samples thicknesses in each case. Moisture content and water release are measured by sample weighing, the corresponding relative humidity is measured by embedded sensors. All three approaches are compared and correlated. The evaluations show only a weak correlation and, in several cases, contradicting results. Samples are considered ready for layering and not ready for layering at the same time, depending on the chosen approach. Due to these contradicting results, a general threshold for a risk of damage cannot be derived based on these measurements. Furthermore, the experiment demonstrates that the measurement of corresponding relative humidity is independent of the screed type or screed composition considered. This makes humidity measurement a potentially very promising approach for the installation of material moisture monitoring systems.

scholarly journals Determination of Mount Merapi Volcanic Earthquake Hypocentre By Using Seismic Wave Polarization Analysis

2020 ◽  
Vol 1 (1) ◽  
pp. 21
Author(s):  
Syahrial Ayub ◽  
Muhammad Zuhdi ◽  
Muhammad Taufik ◽  
Gunawan Gunawan
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Volcanic Earthquake ◽  
Wave Polarization ◽  
Polarization Analysis ◽  
Space Domain ◽  
Volcanic Earthquakes ◽  
Hypocenter Determination ◽  
The Time Domain

Volcanic earthquakes of mount Merapi have been investigated periodically. The investigation aims to determine the hypocenter and epicenter of mount Merapi's volcanic earthquake using wave polarization analysis. The analysis was carried out in three domains, which are the time domain, the frequency domain, and the space domain. The analysis in the time domain was conducted by the arrival time of the volcanic earthquake, and the analysis in the frequency domain was done by observing the spectrum to get information on source frequency and bandwidth passed from polarization analysis, while the analysis in the space domain was conducted especially on hypocenter determination of the volcanic earthquakes. The analysis leads to the frequency of source 6 Hz and a bandwidth of 0.1 Hz. Thus, the hypocenter of volcanic earthquakes by polarization analysis was distributed to depth from 670 m to 3250 m from Merapi's top

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