scholarly journals Comparison of three measurement methods of saturated hydraulic condutivity

2006 ◽  
Vol 3 (3) ◽  
pp. 987-1019 ◽  
Author(s):  
C. Fallico ◽  
E. Migliari ◽  
S. Troisi
Keyword(s):  
Hydraulic Conductivity ◽  
Measurement Method ◽  
Sandy Loam ◽  
Measurement Methods ◽  
Soil Core ◽  
Statistical Parameters ◽  
Factors Affecting ◽  
Average Value ◽  
Constant Head ◽  
Log Normal

Abstract. After pointing out the importance of the saturated hydraulic conductivity (ks) measurements and the difficulties and uncertainties that are present, and after recalling salient aspects of three well-known measurement methods of this parameter (i.e. constant-head tension infiltrometer (TI) method, constant-head pressure infiltrometer (PI) method and soil core (SC) estimates method), the results of an investigation on data which were obtained during a measurement campaign on an area of 800 m2, on a sandy loam hillslope, located in Southern Italy, were carried out again here. Three sets of values of ks, obtained with these measurement methods, were analyzed statistically, verifying that the log-normal distribution describes these better than the normal one; moreover, the more significant statistical parameters of each set were compared (average value , amplitude A, coefficient of variation CV and standard deviation SD), individualizing the more significant differences. The greatest value of hydraulic conductivity was found with method (PI), while the smallest with (SC) and the intermediate with (TI); these differences were translated into macroporosity and into the influence of the single measurement method. Moreover, referring to the possible factors affecting the results, the importance can be noted of the structure, the texture and the soil events, in terms of utilization, which can affect the measure of ks leading often to very different values even for similar soils, but with a different history, independently of the coincidence of the measurement points and they can be determining to explain the differences affecting the results obtained in analogous investigations by other researchers. Having confirmed that generalization is not possible, the need was emphasized to adopt the necessary devices relating to the specific measurement method, case by case, and to carefully explain the obtained results, in the light of the peculiarities and the limits of each situation. Finally, the results of similar statistical analysis carried out on a greater number of ks values, measured through the (TI) and (PI) methods are shown in this paper, with some statistical considerations on the increasing of the measurements number.

scholarly journals Method for measuring intensity of inhomogeneous electrical fields by average value

2021 ◽  
pp. 67-74
Author(s):  
S. V. Biryukov ◽  
◽  
L. V. Tyukina ◽  
A. V. Tyukin ◽  
◽  
...  
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Electric Fields ◽  
High Precision ◽  
Measurement Method ◽  
Measurement Methods ◽  
New Method ◽  
Average Value ◽  
True Value

Measurement and control of the intensity levels of inhomogeneous electric fields with high accuracy is quite a difficult task. The solution to this problem is connected both with the development of new sensors and methods for measuring the electric field strength. The creation of new high-precision electrical induction sensors has exhausted its capabilities at the current level of technology and technology. Therefore, new ideas are needed for solving the problems of high-precision measurement of the electric field strength. One of these ways is the development of new measurement methods. Existing measurement methods characterized by the complexity of the measurement processes, suitability in some cases, and unsuitability in others, do not provide the desired metrological characteristics. Therefore, the work related to the development of methods for measuring the intensity of inhomogeneous electric fields does not stand still, and is relevant. The aim of the study is to create a new method for measuring the strength of electric fields using known sensors, which makes it possible to significantly reduce the error in measuring inhomogeneous electric fields. The idea of constructing a new measurement method is formed. The idea of the method is that in the presence of two physical quantities measured with different sign values of the error, the average value of the physical quantity will always be closer to the true value. Based on this, a new method for measuring the intensity of inhomogeneous electric fields is proposed, associated only with the original measurement process. The measurement method id named «Average value method» (MSZ). The estimation of the error of this method shows a decrease in the measurement error to +5 % with the full spatial measurement range 0a1. Using the «Average value method» it is possible to achieve a significant increase in the accuracy of measuring the strength of inhomogeneous electric fields in a wide spatial range of measurements in comparison with known methods

Hydraulic conductivity measurement of forest catchments

Soil Research ◽  
1980 ◽  
Vol 18 (2) ◽  
pp. 139 ◽  
Author(s):  
T Talsma ◽  
PM Hallam
Keyword(s):  
Hydraulic Conductivity ◽  
Conductivity Measurement ◽  
Measurement Methods ◽  
Conductivity Data ◽  
Small Areas ◽  
Rapid Measurement ◽  
Order Of Magnitude ◽  
Log Normal

Measurements of hydraulic conductivity, K, on four forest catchments that show substantial differences in hydrological behaviour are reported. Field descriptions of principal profile forms and extended profile forms were used as criteria for determining catchment uniformity. Simple and rapid measurement methods for K were necessary. These are described, and one, the well permeameter method, has been further evaluated. Results of many measurements indicated that K distribution was very nearly log-normal for all catchment components and depth intervals studied. Strong variability with respect to K was apparent within each 'uniform' component; however, most of this variability was already present within very small areas. Subdivision of catchments using principal profile forms explained differences in mean K of an order of magnitude, extended principal profile form descriptions were useful to distinguish smaller, but significant, differences in mean K. The usefulness of these catchment conductivity data, for inter-catchment comparison, and for explaining storm-hydrograph shapes of individual catchments, is indicated.

A COMPARISON OF THREE FIELD METHODS FOR MEASURING SATURATED HYDRAULIC CONDUCTIVITY

1985 ◽  
Vol 65 (3) ◽  
pp. 563-573 ◽  
Author(s):  
D. M. LEE ◽  
D. E. ELRICK ◽  
W. D. REYNOLDS ◽  
B. E. CLOTHIER
Keyword(s):  
Hydraulic Conductivity ◽  
Frequency Distribution ◽  
Sandy Loam ◽  
Measurement Techniques ◽  
Saturated Hydraulic Conductivity ◽  
Air Entrapment ◽  
Field Methods ◽  
Normal Frequency ◽  
Log Normal ◽  
Guelph Permeameter

The saturated hydraulic conductivity, Ks, was measured on a loamy sand, a fine sandy loam, a silt loam and a clay at four 100-m2-area sites in southern Ontario. Twenty measurements of Ks were obtained by each of three different measurement techniques at each of the four sites. The techniques included: (1) the air-entry permeameter method; (2) the constant head well permeameter method using the Guelph Permeameter; and (3) the falling-head permeameter method applied to small soil cores. The Ks data were found to be better described by the log-normal frequency distribution than by the normal frequency distribution. Statistical comparison of the mean Ks values [Formula: see text] indicated significant differences between some or all of the methods within each site. This site-method interaction was interpreted in terms of the influence of macropores and air entrapment on each of the measurement techniques. The measured Ks values ranged over an order of magnitude on the sand, one to two orders of magnitude on the loams, and three orders of magnitude on the clay. The [Formula: see text] estimates averaged over the three methods were: 3 × 10−5 m∙s−1 for the sand; 2 × 10−6 m∙s−1 for the loams and 1 × 10−7 m∙s−1 for the clay. Although all techniques were able to discriminate between the three soil types, the best choice of method for any particular situation appears dependent on the required type and accuracy of the Ks measurement, soil type, and the various practical constraints on the investigation. Key words: Air-entry permeameter, Guelph Permeameter, falling-head permeameter, spatial variability, macropores, entrapped air

Assessing bias, precision, and agreement in method comparison studies

2019 ◽  
Vol 29 (3) ◽  
pp. 778-796 ◽  
Author(s):  
Patrick Taffé
Keyword(s):  
Measurement Method ◽  
Method Comparison ◽  
Estimation Procedure ◽  
Measurement Methods ◽  
Repeated Measurements ◽  
Confidence Bands ◽  
The Other ◽  
Reference Standard ◽  
Simultaneous Confidence Bands ◽  
Index Of Agreement

Recently, a new estimation procedure has been developed to assess bias and precision of a new measurement method, relative to a reference standard. However, the author did not develop confidence bands around the bias and standard deviation curves. Therefore, the goal in this paper is to extend this methodology in several important directions. First, by developing simultaneous confidence bands for the various parameters estimated to allow formal comparisons between different measurement methods. Second, by proposing a new index of agreement. Third, by providing a series of new graphs to help the investigator to assess bias, precision, and agreement between the two measurement methods. The methodology requires repeated measurements on each individual for at least one of the two measurement methods. It works very well to estimate the differential and proportional biases, even with as few as two to three measurements by one of the two methods and only one by the other. The repeated measurements need not come from the reference standard but from either measurement methods. This is a great advantage as it may sometimes be more feasible to gather repeated measurements with the new measurement method.

Simplified estimation of unsaturated soil hydraulic conductivity using bulk electrical conductivity and particle size distribution

Soil Research ◽  
2013 ◽  
Vol 51 (1) ◽  
pp. 23 ◽  
Author(s):  
Mohammad Reza Neyshabouri ◽  
Mehdi Rahmati ◽  
Claude Doussan ◽  
Boshra Behroozinezhad
Keyword(s):  
Electrical Conductivity ◽  
Particle Size ◽  
Hydraulic Conductivity ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Unsaturated Soil ◽  
Soil Core ◽  
Soil Hydraulic Conductivity ◽  
Core Samples ◽  
Soil Hydraulic

Unsaturated soil hydraulic conductivity K is a fundamental transfer property of soil but its measurement is costly, difficult, and time-consuming due to its large variations with water content (θ) or matric potential (h). Recently, C. Doussan and S. Ruy proposed a method/model using measurements of the electrical conductivity of soil core samples to predict K(h). This method requires the measurement or the setting of a range of matric potentials h in the core samples—a possible lengthy process requiring specialised devices. To avoid h estimation, we propose to simplify that method by introducing the particle-size distribution (PSD) of the soil as a proxy for soil pore diameters and matric potentials, with the Arya and Paris (AP) model. Tests of this simplified model (SM) with laboratory data on a broad range of soils and using the AP model with available, previously defined parameters showed that the accuracy was lower for the SM than for the original model (DR) in predicting K (RMSE of logK = 1.10 for SM v. 0.30 for DR; K in m s–1). However, accuracy was increased for SM when considering coarse- and medium-textured soils only (RMSE of logK = 0.61 for SM v. 0.26 for DR). Further tests with 51 soils from the UNSODA database and our own measurements, with estimated electrical properties, confirmed good agreement of the SM for coarse–medium-textured soils (<35–40% clay). For these textures, the SM also performed well compared with the van Genuchten–Mualem model. Error analysis of SM results and fitting of the AP parameter showed that most of the error for fine-textured soils came from poorer adequacy of the AP model’s previously defined parameters for defining the water retention curve, whereas this was much less so for coarse-textured soils. The SM, using readily accessible soil data, could be a relatively straightforward way to estimate, in situ or in the laboratory, K(h) for coarse–medium-textured soils. This requires, however, a prior check of the predictive efficacy of the AP model for the specific soil investigated, in particular for fine-textured/structured soils and when using previously defined AP parameters.

Research on Online Measurement Method of Hole Diameter and Position

2013 ◽  
Vol 347-350 ◽  
pp. 197-200
Author(s):  
Yu Gong ◽  
Jing Cai Zhang ◽  
Hong Qi Liu
Keyword(s):  
Comparative Analysis ◽  
Measurement System ◽  
Measurement Method ◽  
Measurement Methods ◽  
Hole Diameter ◽  
Laser Sensor ◽  
Online Measurement ◽  
Online Detection ◽  
Ccd Imaging ◽  
Inductive Sensor

In this paper, research on measurement methods of hole during the parts online detection has been made. Both diameter and position of the hole are going to be detected in the same measurement system. In order to obtain higher accuracy and efficiency, a comparative analysis test of using the contact probes, the inductive sensor, the laser sensor, the forward and back lighting CCD imaging have been achieved. Results show that the contact measurement using inductive sensor is more suitable for the system, for the reason that it has higher reliability and efficiency.

Cross Calibration by FFT Equalization

1997 ◽  
Vol 119 (2) ◽  
pp. 236-242 ◽  
Author(s):  
K. Peleg
Keyword(s):  
Measurement Method ◽  
Functional Relationship ◽  
Measurement Methods ◽  
New Method ◽  
Measurement Systems ◽  
True Value ◽  
Calibration Problem ◽  
Regression Techniques ◽  
The Cross ◽  
Cross Calibration

The classical calibration problem is primarily concerned with comparing an approximate measurement method with a very precise one. Frequently, both measurement methods are very noisy, so we cannot regard either method as giving the true value of the quantity being measured. Sometimes, it is desired to replace a destructive or slow measurement method, by a noninvasive, faster or less expensive one. The simplest solution is to cross calibrate one measurement method in terms of the other. The common practice is to use regression models, as cross calibration formulas. However, such models do not attempt to discriminate between the clutter and the true functional relationship between the cross calibrated measurement methods. A new approach is proposed, based on minimizing the sum of squares of the differences between the absolute values of the Fast Fourier Transform (FFT) series, derived from the readings of the cross calibrated measurement methods. The line taken is illustrated by cross calibration examples of simulated linear and nonlinear measurement systems, with various levels of additive noise, wherein the new method is compared to the classical regression techniques. It is shown, that the new method can discover better the true functional relationship between two measurement systems, which is occluded by the noise.

scholarly journals Stabilization of soil hydraulic properties under a long term no-till system

2014 ◽  
Vol 38 (4) ◽  
pp. 1281-1292 ◽  
Author(s):  
Luis Alberto Lozano ◽  
Carlos Germán Soracco ◽  
Vicente S. Buda ◽  
Guillermo O. Sarli ◽  
Roberto Raúl Filgueira
Keyword(s):  
Hydraulic Conductivity ◽  
Physical Properties ◽  
Hydraulic Properties ◽  
Sandy Loam ◽  
Soil Physical Properties ◽  
Water Retention Curve ◽  
Mean Values ◽  
Tillage System ◽  
Crop Sequence

The area under the no-tillage system (NT) has been increasing over the last few years. Some authors indicate that stabilization of soil physical properties is reached after some years under NT while other authors debate this. The objective of this study was to determine the effect of the last crop in the rotation sequence (1st year: maize, 2nd year: soybean, 3rd year: wheat/soybean) on soil pore configuration and hydraulic properties in two different soils (site 1: loam, site 2: sandy loam) from the Argentinean Pampas region under long-term NT treatments in order to determine if stabilization of soil physical properties is reached apart from a specific time in the crop sequence. In addition, we compared two procedures for evaluating water-conducting macroporosities, and evaluated the efficiency of the pedotransfer function ROSETTA in estimating the parameters of the van Genuchten-Mualem (VGM) model in these soils. Soil pore configuration and hydraulic properties were not stable and changed according to the crop sequence and the last crop grown in both sites. For both sites, saturated hydraulic conductivity, K0, water-conducting macroporosity, εma, and flow-weighted mean pore radius, R0ma, increased from the 1st to the 2nd year of the crop sequence, and this was attributed to the creation of water-conducting macropores by the maize roots. The VGM model adequately described the water retention curve (WRC) for these soils, but not the hydraulic conductivity (K) vs tension (h) curve. The ROSETTA function failed in the estimation of these parameters. In summary, mean values of K0 ranged from 0.74 to 3.88 cm h-1. In studies on NT effects on soil physical properties, the crop effect must be considered.

scholarly journals Source shape and data analysis procedure effects on hydraulic conductivity of a sandy-loam soil determined by ponding infiltration runs

2017 ◽  
Vol 48 (2) ◽  
pp. 71 ◽  
Author(s):  
Vincenzo Bagarello ◽  
Andrea De Santis ◽  
Giuseppe Giordano ◽  
Massimo Iovino
Keyword(s):  
Steady State ◽  
Hydraulic Conductivity ◽  
Sandy Loam ◽  
Analysis Procedure ◽  
Sandy Loam Soil ◽  
Second Phase ◽  
General Validity ◽  
Equivalent Radius ◽  
Loam Soil ◽  
Ks Values

Performing ponding infiltration runs with non-circular sources could represent a good means to sample completely an area of interest. Regardless of the shape of the source, predicting the expected reliability of the collected data by infiltrometers should facilitate soil hydraulic characterisation and also allow a more conscious use of the field data. The influence of the shape of the infiltration source (i.e., circular or square) and the analysis procedure of the steady-state infiltration data on the saturated hydraulic conductivity, Ks, of a sandy-loam soil was tested in this investigation. Circular and square surfaces sampled with the pressure infiltrometer (PI) yielded similar estimates of Ks (i.e., differing by a factor of 1.05-1.16, depending on the calculation method) when an equivalent radius was considered to geometrically describe the square source. With the simplified falling head (SFH) technique, the shape of the source was irrelevant (i.e., circular and square sources yielding Ks values that differed by a factor of 1.19), as theoretically expected. For the steady-state PI experiment, the twoponding depth approach yielded two times smaller Ks values than the one-ponding depth (OPD) approach, probably due to lower steady-state flow rates than those expected for the second phase of the two-level run. The conclusions were that: i) simple infiltrometer experiments (PI, SFH) can be carried out with square sources; and ii) the simplest PI run (OPD approach) is expected to yield the most reliable predictions of Ks. Sampling other soils is advisable in an attempt to make these conclusions of general validity.

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