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Coal mining has an important influence on the soil water content in the vadose zone. In this study, during April, August and October 2015 and June 2016, ground-penetrating radar was used to detect the soil water content of the shallow sand layer (

A transparent interconnects on a 16 layer PCB stack-up with a 100 Ω differential impedance with interconnects is proposed in this paper. To minimize the differential crosstalk, a differential spacing is maintained between interconnects. The transmitter and receiver are demonstrated as Input Buffer Information Specification (IBIS) models. An IBIS model describes the V-I characteristics information about the particular buffer. To provide better channel performance, the interconnect Via structures are optimized in this paper. To observe the channel performance in the frequency domain, S-parameter analysis is performed. To view BER plots, eye diagram and bathtub curve analysis is implemented. To observe the impedance with respect to the propagation delay of the channel, Time Domain Reflectometer (TDR) analysis is performed. Debugging and impedance discontinuity correction are performed using TDR analysis. ADS 9 (Advanced Design System) simulation software is used in this paper.

Although soil nails have been widely used for stabilizing slopes, they are often only partially grouted. Thus, grouted ratio of soil nails should be evaluated to prevent landslides. The purpose of this study was to investigate the suitability of a non-destructive method using electromagnetic waves for evaluating grouted ratio of soil nails. Experimental studies were performed with steel bars, partially grouted steel bars, and fully grouted steel bars in air. Partially and fully grouted steel bars were also installed in soils to simulate soil nails installed on slopes. Electromagnetic waves were generated and received using a time domain reflectometer by configuring a two-conductor transmission line formed by two parallel steel bars or two parallel grouted steel bars. Results of experiments showed that the respective round-trip travel time of electromagnetic waves increased with increasing length of the steel bar, grouted steel bar in air, and grouted steel bar in soils. The velocity of electromagnetic waves was the greatest in steel bars but the lowest in grouted steel bars in soils. In addition, the velocity of the electromagnetic waves decreased with increasing grouted ratio. This study suggests that electromagnetic waves might be useful for evaluating grouted ratios of soil nails to stabilize slopes.

Soil water content (SWC) is a critical attribute in precision irrigation. Direct measurements are costly and relative sparse, so there is interest in methods to predict SWC at unsampled sites from sampled data. The precision of such predictions can be improved, if covariates are incorporated into the predictor. To do that, two efficient ways are: (1) linear mixed effect model (LME), in which the spatial process is obtained by splitting the total variability in a systematic term or mean effect, a spatially correlated component and a random noise, and (2) kriging with external drift (KED), a nonstationary geostatistical technique, assuming covariates to have a linear effect on target variable. Geoelectric sensors provide noninvasive information on soil. Their outputs are quite sensitive to SWC; therefore, they can be used as covariates in SWC predictor. The objective of this work was to compare LME and KED, based on geophysical sensing, to estimate shallow SWC. The surveys were conducted in a south-eastern Italy field, using GPR at two frequencies, 600 and 1,600 MHz, and EMI. Volumetric soil water contents were measured with a Time Domain Reflectometer at 96 locations. Three LMEs, using three correlation functions (spherical, exponential, and Gaussian), were used and compared with KED using a set of cross-validation criteria. The mixed models showed a quite similar behavior even if exponential model outperformed the other two. The covariates used in the mixed models and in KED predictor were different and the results of cross-validation showed a slight out-performance of KED.

In this study the influence of land-surface parameters on latent heat fluxes simulated with the numerical weather prediction model Lokalmodell (LM) of the German Meteorological Service is investigated. The area of interest is the LITFASS area during the LITFASS-2003 campaign. Based on simulations with varying soil and vegetation properties, we confirm that simulated latent heat fluxes strongly depend on soil moisture and leaf area index. Both parameters are difficult to obtain from in situ measurements with sufficient spatial resolution over heterogeneous land surfaces. Therefore, a procedure is proposed to determine area average values of soil moisture from time domain reflectometer measurements performed at a limited number of sites. The area averages cover the 7 × 7 km2 grid cells of the LM around Lindenberg (south-east of Berlin). Furthermore, satellite inferred plant parameters from NOAA–AVHRR are used to initialise model runs; the derived vegetation parameters show notable differences with those in the standard input of LM. The latent heat fluxes from the LM are compared with the aggregated eddy-covariance-measurements, and while the operational LM shows a strong overestimation of latent heat fluxes, it is demonstrated that the application of land-surface parameters derived from measurements can significantly reduce the deviation between the simulated and measured latent heat fluxes.

The principle of operation of a simple, manually controlled Time Domain Reflectometer (TDR meter) for soil moisture measurements, which operates with a needle pulse of 300 ps rise-time, is described. A block diagram and constructions are also given. Construction of a switchless multiple sensor probe, having an inherent delay reference, is presented. Results of measurements of the soil dielectric constant as related to water content, for soils having different bulk densities, textures and humus content show a high correlation. The results agree closely with other investigators measurements with different, more expensive, TDR instruments. The general principle of microprocessor-controlled TDR operated soil moisture meter is considered.