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Showing 1 to 20 of 25 for “"Time Domain Reflectometry (TDR)"”.
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Time domain reflectometry (TDR) techniques for the design of distributed sensors
… of a working system. The system consists of time domain reflectometry (TDR) signal processing equipment and specially designed sensing cables. The TDR equipment sends a high-frequency electric pulse (in the gigahertz range) along the sensing cable. Any change in electric impedance along the …
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The Role of residual stresses in ceramic substrate materials for hybrid thick film applications
… are also tested for electrical performance using Time Domain Reflectometry (TDR) technique. This thesis presents results that indicate that significant tensile residual stresses were generated on the back of the substrate, particularly during the laser scribing phase of the finished device. …
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Electrical Design Considerations and Packaging of Power Electronic Modules
… by the Q3D Extractor and verified by the time-domain reflectometry (TDR) measurements. In most cases, the TDR measurement results closely matched those predicted by the Q3D Extractor. These methods were applied to design and analyze a 50KVA 650V silicon carbide (SiC) half-bridge power …
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Time domain synthesis applied to modeling of microwave structures and material characterization
In this dissertation a new time domain approach for the determination of material properties such as the complex permittivity and the complex permeability in a stripline geometry is presented. The new technique uses both Time Domain Reflectometry (TDR) and Time Domain Transmission (TDT) …
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Wideband characterization of thick film inductors
This work presents a method based on time domain techniques to characterize and model thick film inductor structures. The method is a time domain reflection (TOR) measurement which measures the input port's reflection transfer function of the component under test. The reflection from a short …
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Effects of Transplant Season and Container Size on Landscape Establishment of Kalmia latifolia L.
… 100-L) to adjacent field soil at two depths with time domain reflectometry (TDR) during a dry down cycle. Available water was calculated by subtracting unavailable water (estimated with pressure plates) from volumetric water content (TDR measurements). Adjacent soil contained more available water …
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REAL TIME MONITORING OF VOLUMETRIC WATER CONTENT IN RECLAIMED MINE WASTE USING CONE PENETRATION - TIME DOMAIN REFLECTOMETRY
… through reclaimed mine waste using a new time domain reflectometry (TDR) component added to conventional geotechnical cone penetration testing (CPT). Time domain reflectometry measures the volumetric water content of a soil by characterizing the dielectric constant of the soil – a property …
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New Technologies for Evaluating Putting Green Surface Characteristics
… require a high level of inputs predicated on timely, well informed decisions. Putting green quality is ultimately defined by performance of the turfgrass, and this performance encompasses both (i) the health and vitality of the turfgrass plants, and (ii) the ability of the turfgrass to exist …
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Model-Based Identification of POTS Local Loops for DSL Connectivity Prediction
… a twisted-pair local loop is modeled as a linear time-invariant (LTI) system. Its frequency response is simulated based on the VT-TDL twisted-pair lumped circuit model. Study of the time-domain reflectometry (TDR) response, based on transmission line theory, reveals that the TDR response is a …
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Soil and Site Characterization Using Electromagnetic Waves
… its responses to a step pulse voltage using time domain reflectometry (TDR); (4) Establishment of the relationships between the specific surface area and compressibility, residual shear strength and hydraulic conductivity. This study establishes a framework for quantifying soil engineering …
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Characterization and modeling of magnetic materials and structures
… at the end of a reference transmission line. Time Domain Reflectometry (TDR) technique is used to measure the response waveform from the inductor under test. The response from a short circuit at the location of the inductor is acquired as the reference waveform. The two acquired waveforms are …
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The Hillslope Hydrology of a Mountain Pasture: The Influence of Subsurface Flow on Nitrate and Ammonium Transport
… to the stream. Transects were instrumented with time domain reflectometry (TDR) and porous cup tension lysimeters to monitor soil water and nutrient flux through the pasture and riparian area located at the base of the watershed. The HYDRUS 2-D flow and transport model was used to predict and …
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Multiphysics Simulation and Innovative Characterization of Freezing Soils
… a new instrumentation technique, i.e., thermo-Time Domain Reflectometry (TDR) sensor, was developed to characterize the behaviors of freezing soils. The thermo-TDR combines temperature sensors and a conventional TDR module. The TDR module and algorithm measured the bulk free water content of …
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Galvanic Corrosion of Aluminum/Carbon Composite Systems
… of various designs. The method allows for real-time measurements of galvanic corrosion currents while retaining the original geometry of the conductors.</p> <p>One of the most important findings is that the galvanic corrosion is under <em>cathodic control</em>, which means that the total …
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Hydrogeophysical quantification of infiltration and recharge through soil-filled sinkholes using Time Domain Reflectometry and Electrical Resistivity Tomography
… in two soil-filled sinkholes. Access-tube time domain reflectometry (TDR) was used to derive one-dimensional (1-D) soil moisture profiles. During access-tube installation, 470 soil samples were obtained from depths between 0.3 and to 9.0 m and characterized both physically and chemically. …
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Effects of gully topography on space-time patterns of soil moisture in a semiarid grassland
… about the feedback of gully topography on space-time patterns of soil moisture. The presence of gullies may produce feedbacks to soil moisture that either enhance or diminish gully development. In this study, field observations from PCMS are used to study the effects of gullies on space-time …
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Characterisation of sedimentary structure and hydraulic behaviour within the unsaturated zone of the Triassic Sherwood Sandstone aquifer in North East England
… 3D models of the sedimentary subsurface. Time Domain Reflectometry (TDR) was used to monitor water movement within the Sherwood Sandstone at a site near Selby in Yorkshire, creating a vertical and lateral profile of groundwater movement within the unsaturated zone. Moisture content has …
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Thermal Analysis, Parasitic Extraction, and Wirebond Reliability Studies of Power Electronic Modules
… for an electronic power module using a time domain reflectometry (TDR) method in the form of differential inductance waveforms was developed. These measured parasitic inductance and parasitic capacitance are compared with the parasitic parameters extracted using a Q3D extractor software. …
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Soil Carbon Dioxide Efflux in a Naturally Regenerated and a Planted Clear-Cut on the Virginia Piedmont
… efflux of CO2 from the soil surface can vary in time and space. For this study, soil CO2 efflux was measured in 5 replicate blocks of naturally regenerated and planted loblolly pine (Pinus taeda), shortleaf pine (Pinus echinata), and eastern white pine (Pinus strobus) in a 50-acre clear-cut on …
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Moisture Content Determination and Temperature Profile Modeling of Flexible Pavement Structures
… layers was measured utilizing two types of Time-Domain Reflectometry (TDR) probes that differed in their mode of operation. The temperature profile of the pavement was measured using thermocouples. Data for the moisture content determination was collected and results from two probe types …
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