scholarly journals Construction and calibration of Time Domain Reflectometry probes for assessing soil humidity in distropheric red latosol

2020 ◽  
Vol 8 (12) ◽  
pp. 87-98
Author(s):  
Abinel Bianchessi Dagher ◽  
Arthur Carniato Sanches ◽  
Fernanda Lamede Ferreira De Jesus ◽  
Rodrigo Couto Santos ◽  
Fagner Lopes Theodoro ◽  
...  
Keyword(s):  
Time Domain ◽  
Time Domain Reflectometry ◽  
Soil Samples ◽  
Data Logger ◽  
Indirect Methods ◽  
Precise Method ◽  
Ceramic Capacitor ◽  
Cubic Polynomial ◽  
Red Latosol ◽  
Hydraulics Laboratory

Among the indirect methods of assessing soil moisture, Time Domain Reflectometry (TDR) stands out, which uses the soil dielectric constant to provide volumetric moisture efficiently, quickly and non-destructively. Despite a practical and precise method, TDR has a high cost due to the probes and its Data Logger. In view of this, the present work aims to build and calibrate TDR probes to assess moisture in a Dystrophic Red Latosol. The present work was carried out in the experimental area of the hydraulics laboratory of the Federal University of Grande Dourados (UFGD), located in Dourados-MS, at latitude 22⁰ 12 'south, longitude 54⁰ 59' west and altitude of 434 meters. Each probe built consisted of 3 stainless steel rods (Ø = 3 mm; L = 230 mm) RG 98 cable with 90% mesh and 50 ohm impedance, 4.7 pF ceramic capacitor and BNC connector. The construction procedures followed the following steps: 1- Making the cable, 2- Preparing the rods, 3- Welding the rods to the wires, 4 -Operating test and 5 - finishing phase. After construction, they were calibrated with the characteristic soil of the Region, proceeding with the Probe Reading in two depths (10 and 30 cm) and simultaneous collection of deformed soil samples to determine the moisture based on mass in Laboratory. Subsequently, calibrations with cubic polynomial adjustment were performed. The results showed adjustments with high determination coefficients, and the probes developed showed satisfactory performances.

scholarly journals Measurement of Volumetric Water Content by Gravimetric and Time Domain Reflectometry Methods at Field Experiment with Biochar and N Fertilizer

2019 ◽  
Vol 22 (2) ◽  
pp. 61-64 ◽  
Author(s):  
Lucia Toková ◽  
Dušan Igaz ◽  
Elena Aydin
Keyword(s):  
Field Experiment ◽  
Water Content ◽  
Time Domain ◽  
Soil Property ◽  
Time Domain Reflectometry ◽  
Soil Samples ◽  
Volumetric Water Content ◽  
N Fertilizer ◽  
High Concentration ◽  
Indirect Methods

Abstract There are many methods used for soil water content measurement which we can divide into direct gravimetric methods from using soil samples or indirect methods that are based on the measurement of another soil property which is dependent on soil moisture. The paper presents the findings of volumetric water content measurements with gravimetric and time domain reflectometry (TDR) methods. We focused on four variants in the field experiment in Dolná Malanta (Slovakia): control variant (B0+N0), variant with biochar at dose 20 t.ha−1 without N fertilizer (B20+N0), variant with biochar 20 t.ha−1 and N fertilizer 160 kg.ha−1 (B20+N160) and variant with biochar 20 t.ha−1 and N fertilizer 240 kg.ha−1 (B20+N240). TDR is nowadays a well-established dielectric technique to measure volumetric water content; however, its accuracy is influenced by high concentration of salts in soil. In this paper, we evaluated the effect of added N fertilizer on the measuring accuracy of HydroSense II device that is operating under the TDR principle.

Variation of Matric Suction as a Function of Gypseous Soil Dry Density

2020 ◽  
Vol 38 (6A) ◽  
pp. 861-868
Author(s):  
Hussein H. Karim ◽  
Qasim A. Al-Obaidi ◽  
Ali A. Alshamoosi
Keyword(s):  
Water Content ◽  
Time Domain ◽  
Deformation Behaviour ◽  
Soil Mass ◽  
Matric Suction ◽  
Time Domain Reflectometry ◽  
Dry Density ◽  
Data Logger ◽  
Collapsible Soil ◽  
Gypseous Soil

Gypseous soil is one of the most problematic types of collapsible soils which is affected by many geotechnical factors. The most important factors are the effect of loading and wetting and their relation to soil density, especially when the soil at unsaturation condition. Suction pressure is the main criteria in determining the deformation behaviour of unsaturated collapsible soil when these soils distributed in arid or semi-arid region. In this study, disturbed sample of sandy soil of more than 70% gypsum content is taken from Al-Ramadi city western of Iraq. This study interested to investigate the variation of matric suction with the dry density and their effects on deformation of gypseous soil. For this purpose, a soil-model device provided with high accurate Tensiometers and Time Domain Reflectometry sensors in addition to data logger is designed and manufactured. Tensiometer sensor is used to monitor and measure the matric suction, while the Time Domain Reflectometry is used to monitor and measure the volumetric water content in the soil mass. The results of the tests showed that there is a significant effect of soil dry density on the relationship between the matric suction and water content.

scholarly journals Polymer tensiometers with ceramic cones: direct observations of matric pressures in drying soils

2010 ◽  
Vol 14 (10) ◽  
pp. 1787-1799 ◽  
Author(s):  
M. J. van der Ploeg ◽  
H. P. A. Gooren ◽  
G. Bakker ◽  
C. W. Hoogendam ◽  
C. Huiskes ◽  
...  
Keyword(s):  
Polymer Solution ◽  
Time Domain ◽  
Response Times ◽  
Measurement Range ◽  
Time Domain Reflectometry ◽  
Matric Potential ◽  
Indirect Methods ◽  
Direct Observations ◽  
The Relationship

Abstract. Measuring soil water potentials is crucial to characterize vadose zone processes. Conventional tensiometers only measure until approximately −0.09 MPa, and indirect methods may suffer from the non-uniqueness in the relationship between matric potential and measured properties. Recently developed polymer tensiometers (POTs) are able to directly measure soil matric potentials until the theoretical wilting point (−1.6 MPa). By minimizing the volume of polymer solution inside the POT while maximizing the ceramic area in contact with that polymer solution, response times drop to acceptable ranges for laboratory and field conditions. Contact with the soil is drastically improved with the use of cone-shaped solid ceramics instead of flat ceramics. The comparison between measured potentials by polymer tensiometers and indirectly obtained potentials with time domain reflectometry highlights the risk of using the latter method at low water contents. By combining POT and time domain reflectometry readings in situ moisture retention curves can be measured over the range permitted by the measurement range of both POT and time domain reflectometry.

scholarly journals Polymer tensiometers with ceramic cones: performance in drying soils and comparison with water-filled tensiometers and time domain reflectometry

2009 ◽  
Vol 6 (3) ◽  
pp. 4349-4377 ◽  
Author(s):  
M. J. van der Ploeg ◽  
H. P. A. Gooren ◽  
G. Bakker ◽  
C. W. Hoogendam ◽  
C. Huiskes ◽  
...  
Keyword(s):  
Polymer Solution ◽  
Time Domain ◽  
Response Times ◽  
Time Domain Reflectometry ◽  
Matric Potential ◽  
Indirect Methods ◽  
The Relationship ◽  
Wilting Point ◽  
Water Contents

Abstract. Measuring soil water potentials is crucial to characterize vadose zone processes. Water-filled tensiometers only measure until approximately −0.085 MPa, and indirect methods may suffer from the non-uniqueness in the relationship between matric potential and measured properties. Recently developed polymer tensiometers (POTs) are able to directly measure soil matric potentials until the theoretical wilting point (−1.6 MPa). By minimizing the volume of polymer solution inside the POT while maximizing the ceramic area in contact with that polymer solution, response times drop to acceptable ranges for laboratory and field conditions. Contact with the soil is drastically improved with the use of a cone-shaped solid ceramics instead of flat ceramics. The comparison between measured potentials by polymer tensiometers and indirectly obtained potentials with time domain reflectometry highlights the risk of using the latter method at low water contents. By combining POT and time domain reflectometry readings in situ moisture retention curves can be measured over the range permitted by time domain reflectometry.

Advanced Non-Destructive Fault Isolation Techniques for PCB Substrates Using Magnetic Current Imaging and Terahertz Time Domain Reflectometry

2018 ◽  
Author(s):  
Daechul Choi ◽  
Yoonseong Kim ◽  
Jongyun Kim ◽  
Han Kim
Keyword(s):  
Time Domain ◽  
Quantum Interference ◽  
Flip Chip ◽  
Imaging System ◽  
Time Domain Reflectometry ◽  
Fault Isolation ◽  
Magnetic Current ◽  
Isolation Techniques ◽  
Super Conducting ◽  
Non Destructive

Abstract In this paper, we demonstrate cases for actual short and open failures in FCB (Flip Chip Bonding) substrates by using novel non-destructive techniques, known as SSM (Scanning Super-conducting Quantum Interference Device Microscopy) and Terahertz TDR (Time Domain Reflectometry) which is able to pinpoint failure locations. In addition, the defect location and accuracy is verified by a NIR (Near Infra-red) imaging system which is also one of the commonly used non-destructive failure analysis tools, and good agreement was made.

Super-Conducting Quantum Interference Device Technique: 3-D Localization of a Short within a Flip Chip Assembly

2001 ◽  
Author(s):  
Kendall Scott Wills ◽  
Omar Diaz de Leon ◽  
Kartik Ramanujachar ◽  
Charles P. Todd
Keyword(s):  
Form Factor ◽  
Failure Analysis ◽  
Time Domain ◽  
Quantum Interference ◽  
Flip Chip ◽  
Time Domain Reflectometry ◽  
Interfacial Region ◽  
Precise Localization ◽  
Super Conducting ◽  
Accuracy Of Measurement

Abstract In the current generations of devices the die and its package are closely integrated to achieve desired performance and form factor. As a result, localization of continuity failures to either the die or the package is a challenging step in failure analysis of such devices. Time Domain Reflectometry [1] (TDR) is used to localize continuity failures. However the accuracy of measurement with TDR is inadequate for effective localization of the failsite. Additionally, this technique does not provide direct 3-Dimenstional information about the location of the defect. Super-conducting Quantum Interference Device (SQUID) Microscope is useful in localizing shorts in packages [2]. SQUID microscope can localize defects to within 5um in the X and Y directions and 35um in the Z direction. This accuracy is valuable in precise localization of the failsite within the die, package or the interfacial region in flipchip assemblies.

Failure Analysis of Broken Stitch Bonds in TSSOP Packages Using Scanning Acoustic Microscopy (SAM) and Time Domain Reflectometry (TDR)

2004 ◽  
Author(s):  
Bilal Abd-AlRahman ◽  
Corey Lewis ◽  
Todd Simons
Keyword(s):  
Failure Analysis ◽  
Mechanical Stress ◽  
Time Domain ◽  
Open Circuit ◽  
Time Domain Reflectometry ◽  
Acoustic Microscopy ◽  
Scanning Acoustic Microscopy ◽  
Root Cause ◽  
Analysis Application

Abstract A failure analysis application utilizing scanning acoustic microscopy (SAM) and time domain reflectometry (TDR) for failure analysis has been developed to isolate broken stitch bonds in thin shrink small outline package (TSSOP) devices. Open circuit failures have occurred in this package due to excessive bending of the leads during assembly. The tools and their specific application to this technique as well as the limitations of C-SAM, TDR and radiographic analyses are discussed. By coupling C-SAM and TDR, a failure analyst can confidently determine whether the cause of an open circuit in a TSSOP package is located at the stitch bond. The root cause of the failure was determined to be abnormal mechanical stress placed on the pins during the lead forming operation. While C-SAM and TDR had proven useful in the analysis of TSSOP packages, it can potentially be expanded to other wire-bonded packages.

Time Domain Reflectometry Technique for Failure Analysis

2004 ◽  
Author(s):  
Teoh King Long ◽  
Ko Yin Fern
Keyword(s):  
Failure Analysis ◽  
Time Domain ◽  
Time Domain Reflectometry ◽  
Fault Isolation ◽  
Reference Plane ◽  
First Case ◽  
Main Emphasis ◽  
Plastic Ball ◽  
Solder Balls ◽  
Non Destructive

Abstract In time domain reflectometry (TDR), the main emphasis lies on the reflected waveform. Poor probing contact is one of the common problems in getting an accurate waveform. TDR probe normalization is essential before measuring any TDR waveforms. The advantages of normalization include removal of test setup errors in the original test pulse and the establishment of a measurement reference plane. This article presents two case histories. The first case is about a Plastic Ball Grid Array package consisting of 352 solder balls where the open failure mode was encountered at various terminals after reliability assessment. In the second, a three-digit display LED suspected of an electrical short failure was analyzed using TDR as a fault isolation tool. TDR has been successfully used to perform non-destructive fault isolation in assisting the routine failure analysis of open and short failure. It is shown to be accurate and reduces the time needed to identify fault locations.

Sign in / Sign up

Export Citation Format

Share Document