World Library  


Add to Book Shelf
Flag as Inappropriate
Email this Book

Technical Note:Practical Considerations on the Use of Down-sized Time-domain Reflectometry (Tdr) Probes : Volume 6, Issue 5 (30/11/-0001)

By Mojid, M. A.

Click here to view

Book Id: WPLBN0003973265
Format Type: PDF Article :
File Size: Pages 7
Reproduction Date: 2015

Title: Technical Note:Practical Considerations on the Use of Down-sized Time-domain Reflectometry (Tdr) Probes : Volume 6, Issue 5 (30/11/-0001)  
Author: Mojid, M. A.
Volume: Vol. 6, Issue 5
Language: English
Subject: Science, Hydrology, Earth
Collections: Periodicals: Journal and Magazine Collection (Contemporary), Copernicus GmbH
Historic
Publication Date:
-0001
Publisher: Copernicus Gmbh, Göttingen, Germany
Member Page: Copernicus Publications

Citation

APA MLA Chicago

Mojid, M. A. (-0001). Technical Note:Practical Considerations on the Use of Down-sized Time-domain Reflectometry (Tdr) Probes : Volume 6, Issue 5 (30/11/-0001). Retrieved from http://hawaiilibrary.net/


Description
Description: Department of Irrigation and Water Management, Bangladesh Agricultural University, Mymensingh – 2202, Bangladesh. Nine time-domain reflectometry (TDR) probes, 2 to 10 cm long, were evaluated by comparing their measurement accuracy of TDR-pulse travel time in a sand and sandy loam soil, and electrical conductivity in NaCl solutions. TDR probes <2.5 cm in length generated trough-haped TDR waveforms with rounded corners at the points of the pulse reflection from the probe ends. The sharpness of the pulse reflection on the waveforms increased with both the increasing probe length and soil-water content. The transition time for the propagation of TDR pulse at the probe entrance increased as the soil dried up. The increased transition time caused a rightward movement of the first peak of the waveform at the probe entrance. Because of such peak movement, TDR-support software algorithm determined travel path of TDR pulse through the probe that was smaller than the actual travel path. TDR-measured pulse travel time tTDR varied erratically with the predicted pulse travel time tg (from volumetric soil-water content) for the probes <2.5 cm in length. But, for all probes ³2.5 cm in length, tTDR varied linearly with tg and followed the 1:1 line. TDR could not measure tTDR <300 ps accurately. A minimum probe length Lmin and the lowest allowable soil-water content qmin that the probe can accurately measure govern this lowest pulse travel time tmin. The mean absolute deviation between tTDR and tg was 77 ps for the 2.3 cm long probe and 1.39 ps for all probes ≥2.5 cm in length. All probes ≥2.5 cm in length measured electrical conductivity of salt solutions sTDR that compared well with the electrical conductivity measured by a conductivity meter sm. The length of the probes did not exert any noticeable influence on the accuracy of electrical conductivity measurement.

Keywords: TDR probe, pulse travel time, dielectric constant, electrical conductivity



Summary
Technical Note:
Practical considerations on the use of down-sized time-domain reflectometry (TDR) probes


 

Click To View

Additional Books


  • Characterization of Deep Aquifer Dynamic... (by )
  • Stochastic Inversion of Sequential Hydra... (by )
  • Influence of Hydropedology on Viticultur... (by )
  • Sampling Frequency Trade-offs in the Ass... (by )
  • A Comparison of Regionalisation Methods ... (by )
  • Imperfect Scaling in Distributions of Ra... (by )
  • Use of Satellite Data to Assess the Impa... (by )
  • On Teaching Styles of Water Educators an... (by )
  • Utility of Daily Vs. Monthly Large-scale... (by )
  • Comment on a Hybrid Model of Self Organi... (by )
  • Numerical Simulations of the Impact of C... (by )
  • Coupled Hydrogeophysical Parameter Estim... (by )
Scroll Left
Scroll Right

 



Copyright © World Library Foundation. All rights reserved. eBooks from Hawaii eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.