scholarly journals The GPR-based estimation of the volumetric ice content of dispersed ground in the Central Yakut lowland

2019 ◽  
Vol 59 (1) ◽  
pp. 81-92
Author(s):  
L. G. Neradovsky
Keyword(s):  
Electromagnetic Waves ◽  
Laboratory Data ◽  
Propagation Speed ◽  
High Volume ◽  
Regression Equations ◽  
Heat Flows ◽  
Specific Attenuation ◽  
Ice Content ◽  
Speed Of Propagation ◽  
Logistic Functions

The previously unknown dependence between the volume ice content of frozen dispersed soils and their radiophysical properties (the speed of propagation and specific attenuation of the amplitude of electromagnetic waves) was studied in the layer of annual heat flows of Central Yakutia. The correlation between these characteristics determined in the laboratory and the method of discrete georadiolocation is established. The peculiarity of the connection is the sharp decline in the sensitivity of the propagation speed and the specific attenuation of electromagnetic waves in frozen dispersed soils with high volume ice content (more than  60%). In general, the specific attenuation of electromagnetic waves is more responsive to the change in the volume of ice content of frozen dispersed soils and, thus, it is more preferable to solve the problem of quantitative evaluation of this characteristic. The  proposed method of reusable measurements of signals of georadiolocation with changing position and azimuth of antennas of georadars in the vicinity of the network points of geological and geophysical observations allows to estimate the average values of the propagation speed and specific attenuation of electromagnetic waves with an error of not more than 10%. Due to this, according to the equations of logistic functions it is possible to calculate the average values of volume ice content with an error of 7–11%. With this error, the picture of the probability distribution according to the georadiolocation values of the volume ice content in the averages is completely identical to the laboratory data. On this basis, the found regression equations are recommended to be used for the calculation of the speed of propagation and specific attenuation of electromagnetic waves of background or average values of the volume ice content of frozen dispersed soils of the annual heat transfer layer in any part of the ice complex of the Central Yakut  lowland. 

Wave-Vessel Interactions in Beam Seas

2009 ◽  
Author(s):  
Eirini Spentza ◽  
Chris Swan
Keyword(s):  
Wave Field ◽  
Incident Wave ◽  
Laboratory Data ◽  
Wave Structure ◽  
Wave Pattern ◽  
Scaled Model ◽  
Beam Seas ◽  
Wave Basin ◽  
Wave Slamming ◽  
Speed Of Propagation

This paper concerns the nonlinear interaction of waves with a floating vessel. A detailed experimental study has been undertaken in a 3-D wave basin, using a scaled model tanker subject to a variety of incident wave conditions. The vessel, which is free to move in heave, pitch and roll, has a draft of 14m (at full-scale) and is subject to a range of incident wave periods propagating at right angles to the side shell of the vessel. Measurements undertaken with and without the vessel in place allow the diffracted-radiated wave field to be identified. The laboratory data indicate that the diffracted-radiated wave pattern varies significantly with the incident wave period. Detailed analysis of the experimental results has identified a hitherto unexpected second-order freely propagating wave harmonic generated due to the presence of the vessel. Given its frequency content and its relatively slow speed of propagation, this harmonic leads to a significant steepening of the wave field around the vessel and therefore has an important role to play in terms of the occurrence of wave slamming. Physical insights are provided concerning the latter and the practical implications of the overall wave-structure interactions are considered.

scholarly journals HL7 Terminology Management for Disease Surveillance

2018 ◽  
Vol 10 (1) ◽  
Author(s):  
Emily Roberts ◽  
Theron Jeppson ◽  
Rachelle Boulton ◽  
Josh Ridderhoff
Keyword(s):  
Disease Surveillance ◽  
Communicable Disease ◽  
Laboratory Data ◽  
Data Entry ◽  
High Volume ◽  
Electronic Data ◽  
Disease Surveillance System ◽  
Department Of Health ◽  
Message Structure ◽  
Set Up

Objective: The objective of this abstract is to illustrate how the Utah Department of Health processes a high volume of electronic data. We do this by translating what reporters send within an HL7 message into "epidemiologist" language for consumption into our disease surveillance system.Introduction: In 2013, the Utah Department of Health (UDOH) began working with hospital and reference laboratories to implement electronic laboratory reporting (ELR) of reportable communicable disease data. Laboratories utilize HL7 message structure and standard terminologies such as LOINC and SNOMED to send data to UDOH. These messages must be evaluated for validity, translated, and entered into Utah’s communicable disease surveillance system (UT-NEDSS), where they can be accessed by local and state investigators and epidemiologists. Despite the development and use of standardized terminologies, reporters may use different, outdated versions of these terminologies, may not use the appropriate codes, or may send local, home-grown terminologies. These variations cause problems when trying to interpret test results and automate data processing. UDOH has developed a two-step translation process that allows us to first standardize and clean incoming messages, and then translate them for consumption by UT-NEDSS. These processes allow us to efficiently manage several different terminologies and helps to standardize incoming data, maintain data quality, and streamline the data entry process.Methods: UDOH uses the Electronic Message Staging Area (EMSA) to receive ELR messages, manage terminologies such as LOINC and SNOMED, translate messages, and automatically enter laboratory data into UT-NEDSS. LOINCs and other terms, such as facility name, sent by reporting facilities in an HL7 message are considered child terms. All child terms are mapped to a master LOINC or term and each master LOINC or term is mapped to a specific value within UT-NEDSS. In EMSA, the rules engine used for automated processing of electronic data is set to run at the master level and these rules will determine how the message is processed. No rules are set up or run on child terms.Results: As of 09/20/2017, EMSA contains 2,613 unique child LOINCs that are mapped to 906 master LOINCs. Those 906 master LOINCs are mapped to 179 UT-NEDSS test types and 2003 child facility names are mapped to 1043 master facility namesConclusions: Mapping child terminologies from an HL7 message to a master vocabulary helps us to standardize incoming data, allows us to accept non-standard terminologies and correct reporting errors. Translating this data into a format that is understandable to epidemiologists and investigators enables UT-NEDSS to work effectively in identifying outbreaks and improving health outcomes. This framework is working for ELR and will continue to grow and accept more data and the different terminologies that come with that.

scholarly journals Influence of variability of water content in different states on electromagnetic waves parameters affecting accuracy of GPR measurements of asphalt and concrete pavements

2019 ◽  
Vol 262 ◽  
pp. 06012
Author(s):  
Małgorzata Wutke ◽  
Anna Lejzerowicz ◽  
Wioletta Jackiewicz-Rek ◽  
Andrzej Garbacz
Keyword(s):  
Dielectric Constant ◽  
Electromagnetic Wave ◽  
Water Content ◽  
Electromagnetic Waves ◽  
Atmospheric Precipitation ◽  
Propagation Speed ◽  
Asphalt Pavements ◽  
Concrete Pavements ◽  
Moisture Conditions ◽  
Accuracy And Repeatability

In the paper a water content effect in various states on the variability of the electromagnetic waves parameters is discussed. This variation can affect accuracy and repeatability of asphalt and concrete pavement thickness estimation with GPR method. In case of asphalt pavements, tests were carried out using the air-coupled 1.0 GHz antenna and included three approaches: two on asphalt road and one of asphalt slabs. In the case of concrete slabs, tests were carried out using a ground-coupled 1.6 GHz antenna on two slabs: reinforced and unreinforced. A high variability of the electromagnetic wave parameters was observed depending on moisture conditions. The increase in the humidity of the medium causes a reduction in the propagation speed of the electromagnetic wave (increasing the dielectric constant of the medium), increasing of waves time propagation, decreasing of reflection amplitude and increasing of frequency attenuation, which should be considered when determining the thicknesses of the construction layers. Studies showed that not always higher air humidity, atmospheric precipitation and consequently wet surface indicate a higher dielectric constant of the medium. It can be concluded that not only the humidity and ambient temperature affect the change in the dielectric constant, but also other factors not resulting from the construction of the pavement as well as material microstructure.

Propagation of electromagnetic waves in circular rods in torsion

1963 ◽  
Vol 255 (1059) ◽  
pp. 389-416 ◽  
Keyword(s):  
Magnetic Field ◽  
Magnetic Induction ◽  
Constitutive Equations ◽  
Electromagnetic Waves ◽  
Linear Functions ◽  
Static Deformation ◽  
Polynomial Functions ◽  
Electric And Magnetic Field ◽  
Speed Of Propagation ◽  
Propagation Of Waves

Invariance considerations are employed to write down constitutive equations governing the propagation of electromagnetic waves in isotropic materials with a centre of symmetry which are subject to a static deformation. It is assumed that the dielectric displacement and magnetic induction vectors are linear functions of the electric and magnetic field intensities, respectively, but are general polynomial functions in the quantities which specify the deformation. The theory is employed to examine propagation along circular cylindrical rods in torsion. Rotating waves are produced whose speed of propagation and rate of rotation depend upon the magnitude of the deformation and the properties of the material. The nature of these waves is examined for the general case where there is no restriction either upon the amount of torsion or upon the magnitude of the effect. When the amount of torsion, or the dependence of the effect upon deformation is small, solutions can be obtained based upon those for the propagation of waves in undeformed materials.

scholarly journals An effective-medium model for P-wave velocities of saturated, unconsolidated saline permafrost

Geophysics ◽  
2017 ◽  
Vol 82 (3) ◽  
pp. EN33-EN50 ◽  
Author(s):  
Shan Dou ◽  
Seiji Nakagawa ◽  
Douglas Dreger ◽  
Jonathan Ajo-Franklin
Keyword(s):  
Laboratory Data ◽  
Parameter Tuning ◽  
Effective Medium ◽  
P Wave ◽  
Mixing Ratios ◽  
Wave Velocities ◽  
Effective Medium Model ◽  
Medium Model ◽  
P Wave Velocities ◽  
Ice Content

To better understand the relationship between P-wave velocities and ice content in saturated, unconsolidated saline permafrost, we constructed an effective-medium model based upon ultrasonic P-wave data that were obtained from earlier laboratory studies. The model uses a two-end-member mixing approach in which an ice-filled, fully frozen end member and a water-filled, fully unfrozen end member are mixed together to form the effective medium of partially frozen sediments. This mixing approach has two key advantages: (1) It does not require parameter tuning of the mixing ratios, and (2) it inherently assumes mixed pore-scale distributions of ice that consist of frame-strengthening (i.e., cementing and/or load-bearing) ice and pore-filling ice. The model-predicted P-wave velocities agree well with our laboratory data, demonstrating the effectiveness of the model for quantitatively inferring ice content from P-wave velocities. The modeling workflow is simple and is largely free of calibration parameters — attributes that ease its application in interpreting field data sets.

scholarly journals Capacity Estimation of the Very Short-Range Electromagnetic Underwater Channel Based on Measurements

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Jesús López-Fernández ◽  
Unai Fernández-Plazaola ◽  
Jose F. Paris
Keyword(s):  
Acoustic Waves ◽  
Electromagnetic Waves ◽  
Short Range ◽  
Oil And Gas ◽  
Sea Water ◽  
Water Movement ◽  
Propagation Speed ◽  
Ergodic Capacity ◽  
Transmitter Power ◽  
Offshore Oil And Gas

The significant attenuation experienced by electromagnetic waves in sea water is the main reason why acoustic waves are generally preferred in underwater communication. Nevertheless, acoustic waves have various drawbacks. For example, they are negatively affected by factors such as mechanical noise, slow propagation speed, and, particularly, low bandwidth, which leads to digital links at a lower bit rate. However, in short-range links, these problems can be overcome by reconsidering the use of electric current communications. For instance, data collected by remote-control vehicles in offshore oil and gas and renewable energy plants can be transmitted at distances of even 1 m or less. This study uses previous frequency response measurements taken in deep water to explore the capacity of a short-range electromagnetic underwater channel. Because of water movement, the nonstatic position of the vehicle when the transmission occurs means that the channel is regarded as randomly time-variant. A statistical model is proposed and the ergodic capacity is calculated for a 7 MHz bandwidth channel at distances ranging from 0.5 m to 5 m as well as for different values of transmitter power. The results of this study reflect capacity values of tens of kbps at distances of approximately 5 m to several Mbps at distances of less than 1.5 m.

scholarly journals Retrieval of Reflectivity in a Networked Radar Environment

2008 ◽  
Vol 25 (10) ◽  
pp. 1755-1767 ◽  
Author(s):  
V. Chandrasekar ◽  
S. Lim
Keyword(s):  
Electromagnetic Waves ◽  
State University ◽  
Colorado State University ◽  
Adaptive Sensing ◽  
Specific Attenuation ◽  
Rain Medium ◽  
X Band ◽  
State Water ◽  
Networked Radar ◽  
Using Data

Abstract A system for reflectivity and attenuation retrieval for rain medium in a networked radar environment is described. Electromagnetic waves backscattered from a common volume in networked radar systems are attenuated differently along the different paths. A solution for the specific attenuation distribution is proposed by solving the integral equation for reflectivity and attenuation. The set of governing integral equations describing the backscatter and propagation of common resolution volume are solved simultaneously with constraints on total path attenuation. The proposed algorithm is evaluated based on simulated X-band radar observations synthesized from S-band measurements collected by the Colorado State University–University of Chicago–Illinois State Water Survey (CSU–CHILL) radar. Retrieved reflectivity and specific attenuation using the proposed method show good agreement with simulated reflectivity and specific attenuation. Preliminary demonstration of the network-based retrieval using data from the Center for Collaborative Adaptive Sensing of the Atmosphere (CASA) IP-1 radar network are also presented.

scholarly journals Determination of adjusted range corrections measured by electro-optical systems

2021 ◽  
Vol 2131 (2) ◽  
pp. 022048
Author(s):  
V I Kushtin ◽  
A N Ivanov
Keyword(s):  
Electromagnetic Waves ◽  
Propagation Speed ◽  
Optical Systems ◽  
Signal Delay ◽  
Atmospheric Models ◽  
Ellipsoidal Model ◽  
Wave Path ◽  
Measured Line ◽  
Different Characteristics

Abstract Electromagnetic radiation used to determine ranges passes through media with different characteristics that affect the electromagnetic waves propagation speed and, accordingly, the accuracy of distance determination. The problem of the radio signal delay due to the influence of the atmosphere is an urgent problem, the solution of which is currently limited mainly to the calculation of range corrections using various atmospheric models. Depending on the required accuracy, the length of the measured line, the range of zenith distances, the availability of information about the state of the atmosphere, a flat, spherical, ellipsoidal model of atmospheres is used to determine the range corrections. In view of the fact that the parameters of the atmosphere characterizing its state along the electromagnetic wave path at the time of measurement, as a rule, are unknown, it becomes necessary to apply one or another hypothesis about the distribution of atmospheric parameters with height. In this paper, we propose a solution to the problem of determining corrections to the measured ranges from the known parameters of the atmosphere only at the initial and final points of the electromagnetic waves’ trajectory.

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