A time domain transmission sensor with TDR performance characteristics

Blonquist, J. M.; Jones, Scott B.; Robinson, David A.

doi:10.1016/j.jhydrol.2005.04.005

Cited by 96 publications

(72 citation statements)

References 26 publications

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“…The calibration function depends on the measuring principle, sensor design and soil specifications. More recently, novel time domain transmission sensors have become available that are said to provide a performance similar to the TDR method at a reduced cost (Blonquist et al, 2005). These measurement methods can also be used for materials other than soil, as long as the relative permittivity of the dry material is significantly different from that of water.…”

Section: Permittivitymentioning

confidence: 99%

Comparison of different methods for the in situ measurement of forest litter moisture content

Schunk¹,

Rüth²,

Leuchner³

et al. 2016

Nat. Hazards Earth Syst. Sci.

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Abstract. Dead fine fuel (e.g., litter) moisture content is an important parameter for both forest fire and ecological applications as it is related to ignitability, fire behavior and soil respiration. Real-time availability of this value would thus be a great benefit to fire risk management and prevention. However, the comprehensive literature review in this paper shows that there is no easy-to-use method for automated measurements available. This study investigates the applicability of four different sensor types (permittivity and electrical resistance measuring principles) for this measurement. Comparisons were made to manual gravimetric reference measurements carried out almost daily for one fire season and overall agreement was good (highly significant correlations with 0.792 < = r < = 0.947, p < 0.001). Standard deviations within sensor types were linearly correlated to daily sensor mean values; however, above a certain threshold they became irregular, which may be linked to exceedance of the working ranges. Thus, measurements with irregular standard deviations were considered unusable and relationships between gravimetric and automatic measurements of all individual sensors were compared only for useable periods. A large drift in these relationships became obvious from drought to drought period. This drift may be related to installation effects or settling and decomposition of the litter layer throughout the fire season. Because of the drift and the in situ calibration necessary, it cannot be recommended to use the methods presented here for monitoring purposes and thus operational hazard management. However, they may be interesting for scientific studies when some manual fuel moisture measurements are made anyway. Additionally, a number of potential methodological improvements are suggested.

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Section: Permittivitymentioning

confidence: 99%

Comparison of different methods for the in situ measurement of forest litter moisture content

Schunk¹,

Rüth²,

Leuchner³

et al. 2016

Nat. Hazards Earth Syst. Sci.

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“…CC-BY 3.0 License. less user-ability requirement of TDT waveform analysis (Blonquist Jr. et al, 2005). Understanding the desalinization process and the management of saltwater 80 intrusion in coastal aquifers is a critical challenge in the tsunami damaged farmlands.…”

Section: Introductionmentioning

confidence: 99%

“…), showing travel time and maximum slope of the TDT waveform. The resulting digitized waveform can be analyzed by taking the first and second derivatives and extracting maximum inflection points and maximum slope points in the waveform (Blonquist Jr. et al, 2005). While the entire TDT waveforms were not received by CR800, permittivity and EC were 145 calculated from the readings of maximum inflection points and maximum slope.…”

mentioning

confidence: 99%

Investigation of rootzone salinity with field monitoring system at tsunami affected rice fields in Miyagi, Japan

Tokumoto

Chiba

Mizoguchi

et al. 2016

Preprint

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After the 2011 Tohoku earthquake, thirteen thousand hectares of farmlands 10 were damaged by massive Tsunami near coastal sites in Miyagi, Japan. Some eighty percent of the damaged farmlands have been recovered in 2014, but subsidence and high salinity groundwater make it difficult to completely remove salinity from the soil.To solve the problem, management of saltwater intrusion plays an important role in rootzone salinity control with the Field Monitoring System (FMS), which is remote 15 sensing technology of wireless real-time soil data through the internet data sever to investigate high soil moisture and high salinity in tsunami affected fields. Using the FMS with the time domain transmission system, we monitored soil moisture, electrical conductivity (EC), groundwater level, and EC of groundwater at tsunami damaged paddy fields. The field measurements of the FMS were conducted at two sites of 20 tsunami damaged farmlands in Iwanuma and Higashimatsushima of Miyagi prefecture, Japan. After the Tohoku disaster, co-seismic subsidence of 17-21 cm and 50-60 cm of the land was reported at the sites, respectively. Our findings were high EC of groundwater (> 35 dS m -1 ) due to intrusion of sea water into groundwater in 2013.Although the shallow groundwater provided salinity to the soil surface in 2014, the 25 SOIL Discuss.,

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“…This technique is simple, rapid, in situ and nondestructive. The principles and devices of TDR technique have been reviewed by other researchers [1,2,12]. Despite the advantages, these devices have not been widely applied to food materials.…”

Section: Introductionmentioning

confidence: 99%

“…The principles of TDR devices have been discussed in detail by many researchers [1,11,19]. As an electric field travels through a material, the energy is dissipated in two ways.…”

Section: Introductionmentioning

confidence: 99%

Measurement of glucose and sucrose concentrations by time-domain reflectometry

Lin

Chen

2008

Sens. & Instrumen. Food Qual.

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The time-domain reflectometry (TDR) technology was applied in this study to measure sugar concentrations below 10%. The influences of temperature and species of sugars were evaluated. The results indicated that the TDR methods could be used for measuring sugar concentrations. The slope of TDR waveforms at a specific range was found to be a function of sugar concentrations and temperature. The differences in TDR waves derived from various sugar species and TDR probes were insignificant. The effects of the concentration and temperature on the slope of the TDR waveforms were established by regression analysis. The accuracy of the TDR method to measure sugar concentrations in new independent samples was within 0.365%. This technique is inexpensive, rapid, in-situ and suitable for online applications.

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A time domain transmission sensor with TDR performance characteristics

Cited by 96 publications

References 26 publications

Comparison of different methods for the in situ measurement of forest litter moisture content

Comparison of different methods for the in situ measurement of forest litter moisture content

Investigation of rootzone salinity with field monitoring system at tsunami affected rice fields in Miyagi, Japan

Measurement of glucose and sucrose concentrations by time-domain reflectometry

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