40 CFR 63.4768 - What are the requirements for continuous parameter monitoring system installation, operation, and...

Code of Federal Regulations, 2013 CFR

2013-07-01

...) Locate the temperature sensor in a position that provides a representative temperature. (ii) Use a temperature sensor with a measurement sensitivity of 4 degrees Fahrenheit or 0.75 percent of the temperature value, whichever is larger. (iii) Shield the temperature sensor system from electromagnetic interference...

40 CFR 63.4168 - What are the requirements for continuous parameter monitoring system installation, operation, and...

Code of Federal Regulations, 2012 CFR

2012-07-01

... requirements in paragraphs (c)(3)(i) through (vii) of this section. (i) Locate the temperature sensor in a position that provides a representative temperature. (ii) Use a temperature sensor with a measurement...) Shield the temperature sensor system from electromagnetic interference and chemical contaminants. (iv) If...

40 CFR 63.4168 - What are the requirements for continuous parameter monitoring system installation, operation, and...

Code of Federal Regulations, 2013 CFR

2013-07-01

... requirements in paragraphs (c)(3)(i) through (vii) of this section. (i) Locate the temperature sensor in a position that provides a representative temperature. (ii) Use a temperature sensor with a measurement...) Shield the temperature sensor system from electromagnetic interference and chemical contaminants. (iv) If...

The measurement procedure in the SEMONT monitoring system.

PubMed

Djuric, Nikola; Kljajic, Dragan; Kasas-Lazetic, Karolina; Bajovic, Vera

2014-03-01

The measurement procedure of the open area in situ electric field strength is presented, acquiring the real field data for testing of the Serbian electromagnetic field monitoring network (SEMONT) and its Internet portal. The SEMONT monitoring system introduces an advanced approach of wireless sensor network utilization for the continuous supervision of overall and cumulative level of electromagnetic field over the observed area. The aim of the SEMONT system is to become a useful tool for the national and municipal agencies for the environmental protection, regarding the electromagnetic pollution monitoring and the exposure assessment of the general population. Considering the public concern on the potentially harmful effects of the long-term exposure to electromagnetic radiation, as well as the public transparency principle that is incorporated into the Serbian law on non-ionizing radiation protection, the SEMONT monitoring system is designed for the long-term continuous monitoring, presenting real-time measurement results, and corresponding exposure assessment over the public Internet network.

Improved design and in-situ measurements of new beam position monitors for Indus-2

NASA Astrophysics Data System (ADS)

Kumar, M.; Babbar, L. K.; Holikatti, A. C.; Yadav, S.; Tyagi, Y.; Puntambekar, T. A.; Senecha, V. K.

2018-01-01

Beam position monitors (BPM) are important diagnostic devices used in particle accelerators to monitor position of the beam for various applications. Improved version of button electrode BPM has been designed using CST Studio Suite for Indus-2 ring. The new BPMs are designed to replace old BPMs which were designed and installed more than 12 years back. The improved BPMs have higher transfer impedance, resonance free output signal, equal sensitivity in horizontal and vertical planes and fast decaying wakefield as compared to old BPMs. The new BPMs have been calibrated using coaxial wire method. Measurement of transfer impedance and time domain signals has also been performed in-situ with electron beam during Indus-2 operation. The calibration and beam based measurements results showed close agreement with the design parameters. This paper presents design, electromagnetic simulations, calibration result and in-situ beam based measurements of newly designed BPMs.

[Organization of monitoring of electromagnetic radiation in the urban environment].

PubMed

Savel'ev, S I; Dvoeglazova, S V; Koz'min, V A; Kochkin, D E; Begishev, M R

2008-01-01

The authors describe new current approaches to monitoring the environment, including the sources of electromagnetic radiation and noise. Electronic maps of the area under study are shown to be made, by constructing the isolines or distributing the actual levels of controlled factors. These current approaches to electromagnetic and acoustic monitoring make it possible to automate a process of measurements, to analyze the established situation, and to simplify the risk controlling methodology.

Rock Burst Monitoring by Integrated Microseismic and Electromagnetic Radiation Methods

NASA Astrophysics Data System (ADS)

Li, Xuelong; Wang, Enyuan; Li, Zhonghui; Liu, Zhentang; Song, Dazhao; Qiu, Liming

2016-11-01

For this study, microseismic (MS) and electromagnetic radiation (EMR) monitoring systems were installed in a coal mine to monitor rock bursts. The MS system monitors coal or rock mass ruptures in the whole mine, whereas the EMR equipment monitors the coal or rock stress in a small area. By analysing the MS energy, number of MS events, and EMR intensity with respect to rock bursts, it has been shown that the energy and number of MS events present a "quiet period" 1-3 days before the rock burst. The data also show that the EMR intensity reaches a peak before the rock burst and this EMR intensity peak generally corresponds to the MS "quiet period". There is a positive correlation between stress and EMR intensity. Buckling failure of coal or rock depends on the rheological properties and occurs after the peak stress in the high-stress concentration areas in deep mines. The MS "quiet period" before the rock burst is caused by the heterogeneity of the coal and rock structures, the transfer of high stress into internal areas, locked patches, and self-organized criticality near the stress peak. This study increases our understanding of coal and rock instability in deep mines. Combining MS and EMR to monitor rock burst could improve prediction accuracy.

Control and monitoring method and system for electromagnetic forming process

DOEpatents

Kunerth, Dennis C.; Lassahn, Gordon D.

1990-01-01

A process, system, and improvement for a process for electromagnetic forming of a workpiece in which characteristics of the workpiece such as its geometry, electrical conductivity, quality, and magnetic permeability can be determined by monitoring the current and voltage in the workcoil. In an electromagnet forming process in which a power supply provides current to a workcoil and the electromagnetic field produced by the workcoil acts to form the workpiece, the dynamic interaction of the electromagnetic fields produced by the workcoil with the geometry, electrical conductivity, and magnetic permeability of the workpiece, provides information pertinent to the physical condition of the workpiece that is available for determination of quality and process control. This information can be obtained by deriving in real time the first several time derivatives of the current and voltage in the workcoil. In addition, the process can be extended by injecting test signals into the workcoil during the electromagnetic forming and monitoring the response to the test signals in the workcoil.

Electromagnetic tracking of motion in the proximity of computer generated graphical stimuli: a tutorial.

PubMed

Schnabel, Ulf H; Hegenloh, Michael; Müller, Hermann J; Zehetleitner, Michael

2013-09-01

Electromagnetic motion-tracking systems have the advantage of capturing the tempo-spatial kinematics of movements independently of the visibility of the sensors. However, they are limited in that they cannot be used in the proximity of electromagnetic field sources, such as computer monitors. This prevents exploiting the tracking potential of the sensor system together with that of computer-generated visual stimulation. Here we present a solution for presenting computer-generated visual stimulation that does not distort the electromagnetic field required for precise motion tracking, by means of a back projection medium. In one experiment, we verify that cathode ray tube monitors, as well as thin-film-transistor monitors, distort electro-magnetic sensor signals even at a distance of 18 cm. Our back projection medium, by contrast, leads to no distortion of the motion-tracking signals even when the sensor is touching the medium. This novel solution permits combining the advantages of electromagnetic motion tracking with computer-generated visual stimulation.

78 FR 28733 - Medical Devices; General Hospital and Personal Use Monitoring Devices; Classification of the...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-16

... Toxicology Testing. Labeling (dose limits). Electromagnetic incompatibility........ Electromagnetic... analysis and nonclinical testing must validate electromagnetic compatibility performance, wireless... electromagnetic compatibility performance, wireless performance, and electrical safety; and (4) Labeling must...

Current status and performance of the BESIII electromagnetic calorimeter

NASA Astrophysics Data System (ADS)

Fang, Jian; Wang, Zhigang

2012-12-01

The design and construction of the BESIII electromagnetic calorimeter is introduced briefly. Radiation dose of CsI(Tl) crystals is monitored and history graph of integral dose of crystals is showed. LED-fiber system is used for monitoring the EMC light output, and large decrease of light output of several crystals is discussed. BESIII electromagnetic calorimeter works very well and its performance reach the design value.

Area Monitoring for Detection of Leaks and/or Flames

NASA Technical Reports Server (NTRS)

Mian, Zahid F. (Inventor); Gamache, Ronald W. (Inventor); Glasser, Nick (Inventor)

2015-01-01

A solution for monitoring an area for the presence of a flame and/or a leak, such as from a pressurized fluid, is provided. An imaging device can be used that acquires image data based on electromagnetic radiation having wavelengths only corresponding to at least one region of the electromagnetic spectrum in which electromagnetic radiation from an ambient light source is less than the electromagnetic radiation emitted by at least one type of flame for which the presence within the area is being monitored. An acoustic device can be used that is configured to acquire acoustic data for the area and enhance acoustic signals in a range of frequencies corresponding to a leak of a pressurized fluid present in the area.

Area Monitoring for Detection of Leaks And/Or Flames

NASA Technical Reports Server (NTRS)

Mian, Zahid F. (Inventor); Gamache, Ronald W. (Inventor); Glasser, Nicholas (Inventor)

2017-01-01

A solution for monitoring an area for the presence of a flame and/or a leak, such as from a pressurized fluid, is provided. An imaging device can be used that acquires image data based on electromagnetic radiation having wavelengths only corresponding to at least one region of the electromagnetic spectrum in which electromagnetic radiation from an ambient light source is less than the electromagnetic radiation emitted by at least one type of flame for which the presence within the area is being monitored. An acoustic device can be used that is configured to acquire acoustic data for the area and enhance acoustic signals in a range of frequencies corresponding to a leak of a pressurized fluid present in the area.

A monitor for the laboratory evaluation of control integrity in digital control systems operating in harsh electromagnetic environments

NASA Technical Reports Server (NTRS)

Belcastro, Celeste M.; Fischl, Robert; Kam, Moshe

1992-01-01

This paper presents a strategy for dynamically monitoring digital controllers in the laboratory for susceptibility to electromagnetic disturbances that compromise control integrity. The integrity of digital control systems operating in harsh electromagnetic environments can be compromised by upsets caused by induced transient electrical signals. Digital system upset is a functional error mode that involves no component damage, can occur simultaneously in all channels of a redundant control computer, and is software dependent. The motivation for this work is the need to develop tools and techniques that can be used in the laboratory to validate and/or certify critical aircraft controllers operating in electromagnetically adverse environments that result from lightning, high-intensity radiated fields (HIRF), and nuclear electromagnetic pulses (NEMP). The detection strategy presented in this paper provides dynamic monitoring of a given control computer for degraded functional integrity resulting from redundancy management errors, control calculation errors, and control correctness/effectiveness errors. In particular, this paper discusses the use of Kalman filtering, data fusion, and statistical decision theory in monitoring a given digital controller for control calculation errors.

Electromagnetic Monitoring and Control of a Plurality of Nanosatellites

NASA Technical Reports Server (NTRS)

Soloway, Donald I. (Inventor)

2017-01-01

A method for monitoring position of and controlling a second nanosatellite (NS) relative to a position of a first NS. Each of the first and second NSs has a rectangular or cubical configuration of independently activatable, current-carrying solenoids, each solenoid having an independent magnetic dipole moment vector, .mu.1 and .mu.2. A vector force F and a vector torque are expressed as linear or bilinear combinations of the first set and second set of magnetic moments, and a distance vector extending between the first and second NSs is estimated. Control equations are applied to estimate vectors, .mu.1 and .mu.2, required to move the NSs toward a desired NS configuration. This extends to control of N nanosatellites.

A Prospective Cohort Study of Gated Stereotactic Liver Radiation Therapy Using Continuous Internal Electromagnetic Motion Monitoring.

PubMed

Worm, Esben S; Høyer, Morten; Hansen, Rune; Larsen, Lars P; Weber, Britta; Grau, Cai; Poulsen, Per R

2018-06-01

Intrafraction motion can compromise the treatment accuracy in liver stereotactic body radiation therapy (SBRT). Respiratory gating can improve treatment delivery; however, gating based on external motion surrogates is inaccurate. The present study reports the use of Calypso-based internal electromagnetic motion monitoring for gated liver SBRT. Fifteen patients were included in a study of 3-fraction respiratory gated liver SBRT guided by 3 implanted electromagnetic transponders. The planning target volume was created by a 5-mm axial and 7-mm (n = 12) or 10-mm (n = 3) craniocaudal expansion of the clinical target volume (CTV) and covered with 67% of the prescribed CTV mean dose. Treatment was gated to the end-exhale phase of the respiratory cycle with beam-on when the target deviated <3 mm (left-right/anteroposterior) and 4 mm (craniocaudal) from the planned position, according to the monitored (25-Hz) transponder centroid position. The couch was adjusted remotely if baseline drifts >1 to 2 mm occurred. Log files of transponder motion were used to determine the geometric error and reconstruct the delivered CTV dose in the actual gated treatments and in simulated nongated treatments. No severe side effects were observed in relation to transponder implantation. All 45 treatment fractions were successfully guided using the Calypso system. The mean number of couch corrections during each gated fraction was 2.8 (range 0-7). The mean duty cycle during gated treatment was 62.5% (range 29.1%-84.9%). Without gating, the mean 3-dimensional geometric error during a fraction would have been 5.4 mm (range 2.7-12.1). Gating reduced this error to 2.0 mm (range 1.2-3.0). The patient mean reduction in minimum dose to 95% of the CTV relative to the planned dose was 6.0 percentage points (range 0.7-22.0) without gating and 0.8 percentage point (range 0.2-2.0) with gating. Gating using internal motion monitoring was successfully applied for liver SBRT. It markedly improved the geometric and dosimetric accuracy compared with nongated standard treatment. Copyright © 2018 Elsevier Inc. All rights reserved.

Electromagnetic Radiofrequency Radiation Emitted from GSM Mobile Phones Decreases the Accuracy of Home Blood Glucose Monitors

PubMed Central

Mortazavi, SMJ; Gholampour, M; Haghani, M; Mortazavi, G; Mortazavi, AR

2014-01-01

Mobile phones are two-way radios that emit electromagnetic radiation in microwave range. As the number of mobile phone users has reached 6 billion, the bioeffects of exposure to mobile phone radiation and mobile phone electromagnetic interference with electronic equipment have received more attention, globally. As self-monitoring of blood glucose can be a beneficial part of diabetes control, home blood glucose testing kits are very popular. The main goal of this study was to investigate if radiofrequency radiation emitted from a common GSM mobile phone can alter the accuracy of home blood glucose monitors. Forty five female nondiabetic students aged 17-20 years old participated in this study. For Control-EMF group (30 students), blood glucose concentration for each individual was measured in presence and absence of radiofrequency radiation emitted by a common GSM mobile phone (HTC touch, Diamond 2) while the phone was ringing. For Control- Repeat group (15 students), two repeated measurements were performed for each participant in the absence of electromagnetic fields. The magnitude of the changes between glucose levels in two repeated measurements (|ΔC|) in Control-Repeat group was 1.07 ± 0.88 mg/dl while this magnitude for Control-EMF group was 7.53 ± 4.76 mg/dl (P < 0.001, two-tailed test). To the best of our knowledge, this is the first study to assess the electromagnetic interference in home blood glucose monitors. It can be concluded that electromagnetic interference from mobile phones has an adverse effect on the accuracy of home blood glucose monitors. We suggest that mobile phones should be used at least 50 cm away from home blood glucose monitors. PMID:25505778

Electromagnetic Radiofrequency Radiation Emitted from GSM Mobile Phones Decreases the Accuracy of Home Blood Glucose Monitors.

PubMed

Mortazavi, Smj; Gholampour, M; Haghani, M; Mortazavi, G; Mortazavi, Ar

2014-09-01

Mobile phones are two-way radios that emit electromagnetic radiation in microwave range. As the number of mobile phone users has reached 6 billion, the bioeffects of exposure to mobile phone radiation and mobile phone electromagnetic interference with electronic equipment have received more attention, globally. As self-monitoring of blood glucose can be a beneficial part of diabetes control, home blood glucose testing kits are very popular. The main goal of this study was to investigate if radiofrequency radiation emitted from a common GSM mobile phone can alter the accuracy of home blood glucose monitors. Forty five female nondiabetic students aged 17-20 years old participated in this study. For Control-EMF group (30 students), blood glucose concentration for each individual was measured in presence and absence of radiofrequency radiation emitted by a common GSM mobile phone (HTC touch, Diamond 2) while the phone was ringing. For Control- Repeat group (15 students), two repeated measurements were performed for each participant in the absence of electromagnetic fields. The magnitude of the changes between glucose levels in two repeated measurements (|ΔC|) in Control-Repeat group was 1.07 ± 0.88 mg/dl while this magnitude for Control-EMF group was 7.53 ± 4.76 mg/dl (P < 0.001, two-tailed test). To the best of our knowledge, this is the first study to assess the electromagnetic interference in home blood glucose monitors. It can be concluded that electromagnetic interference from mobile phones has an adverse effect on the accuracy of home blood glucose monitors. We suggest that mobile phones should be used at least 50 cm away from home blood glucose monitors.

A new array system for multiphysics (MT, LOTEM, and microseismics) with focus on reservoir monitoring

NASA Astrophysics Data System (ADS)

Strack, K.; Davydycheva, S.; Hanstein, T.; Smirnov, M.

2017-07-01

Over the last 6 years we developed an array system for electromagnetic acquisition (magnetotelluric & long offset transient electromagnetics [LOTEM]) that includes microseismic acquisition. While predominantly used for magnetotellurics, we focus on the autonomous operation as reservoir monitoring system including a shallow borehole receiver and 100/150 KVA transmitter. A marine extension is also under development. For Enhanced Oil recovery (EOR), in addition to reservoir flood front movements, reservoir seal integrity has become an issue [1]. Seal integrity is best addressed with microseismics while the water flood front is best addressed with electromagnetics. Since the flooded reservoir is conductive and the hydrocarbon saturated part is resistive, you need both magnetic and electric fields. The fluid imaging is addressed using electromagnetics. To overcome the volume-focus inherent to electromagnetics a new methodology to focus the sensitivity under the receiver is proposed. Field data and 3D modeling confirm this could increase the efficiency of LOTEM to reservoir monitoring.

Time-lapse monitoring of soil water content using electromagnetic conductivity imaging

USDA-ARS?s Scientific Manuscript database

The volumetric soil water content (VWC) is fundamental to agriculture. Unfortunately, the universally accepted thermogravimetric method is labour intensive and time-consuming to use for field-scale monitoring. Electromagnetic (EM) induction instruments have proven to be useful in mapping the spatio-...

Prototyping of beam position monitor for medium energy beam transport section of RAON heavy ion accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jang, Hyojae, E-mail: lkcom@ibs.re.kr; Jin, Hyunchang; Jang, Ji-Ho

2016-02-15

A heavy ion accelerator, RAON is going to be built by Rare Isotope Science Project in Korea. Its target is to accelerate various stable ions such as uranium, proton, and xenon from electron cyclotron resonance ion source and some rare isotopes from isotope separation on-line. The beam shaping, charge selection, and modulation should be applied to the ions from these ion sources because RAON adopts a superconducting linear accelerator structure for beam acceleration. For such treatment, low energy beam transport, radio frequency quadrupole, and medium energy beam transport (MEBT) will be installed in injector part of RAON accelerator. Recently, developmentmore » of a prototype of stripline beam position monitor (BPM) to measure the position of ion beams in MEBT section is under way. In this presentation, design of stripline, electromagnetic (EM) simulation results, and RF measurement test results obtained from the prototyped BPM will be described.« less

Monitoring scale-specific and temporal variation in electromagnetic conductivity images

USDA-ARS?s Scientific Manuscript database

In the semi-arid and arid landscapes of southwest USA, irrigation sustains agricultural activity; however, there are increasing demands on water resources. As such spatial temporal variation of soil moisture needs to be monitored. One way to do this is to use electromagnetic (EM) induction instrumen...

Descriptive Study of Electromagnetic Wave Distribution for Various Seating Positions: Using Digital Textbooks

ERIC Educational Resources Information Center

Seomun, GyeongAe; Kim, YoungHwan; Lee, Jung-Ah; Jeong, KwangHoon; Park, Seon-A; Kim, Miran; Noh, Wonjung

2014-01-01

To better understand environmental electromagnetic wave exposure during the use of digital textbooks by elementary school students, we measured numeric values of the electromagnetic fields produced by tablet personal computers (TPCs). Specifically, we examined the distribution of the electromagnetic waves for various students' seating positions in…

Respiratory gating based on internal electromagnetic motion monitoring during stereotactic liver radiation therapy: First results.

PubMed

Poulsen, Per Rugaard; Worm, Esben Schjødt; Hansen, Rune; Larsen, Lars Peter; Grau, Cai; Høyer, Morten

2015-01-01

Intrafraction motion may compromise the target dose in stereotactic body radiation therapy (SBRT) of tumors in the liver. Respiratory gating can improve the treatment delivery, but gating based on an external surrogate signal may be inaccurate. This is the first paper reporting on respiratory gating based on internal electromagnetic monitoring during liver SBRT. Two patients with solitary liver metastases were treated with respiratory-gated SBRT guided by three implanted electromagnetic transponders. The treatment was delivered in end-exhale with beam-on when the centroid of the three transponders deviated less than 3 mm [left-right (LR) and anterior-posterior (AP) directions] and 4mm [cranio-caudal (CC)] from the planned position. For each treatment fraction, log files were used to determine the transponder motion during beam-on in the actual gated treatments and in simulated treatments without gating. The motion was used to reconstruct the dose to the clinical target volume (CTV) with and without gating. The reduction in D95 (minimum dose to 95% of the CTV) relative to the plan was calculated for both treatment courses. With gating the maximum course mean (standard deviation) geometrical error in any direction was 1.2 mm (1.8 mm). Without gating the course mean error would mainly increase for Patient 1 [to -2.8 mm (1.6 mm) (LR), 7.1 mm (5.8 mm) (CC), -2.6 mm (2.8mm) (AP)] due to a large systematic cranial baseline drift at each fraction. The errors without gating increased only slightly for Patient 2. The reduction in CTV D95 was 0.5% (gating) and 12.1% (non-gating) for Patient 1 and 0.3% (gating) and 1.7% (non-gating) for Patient 2. The mean duty cycle was 55%. Respiratory gating based on internal electromagnetic motion monitoring was performed for two liver SBRT patients. The gating added robustness to the dose delivery and ensured a high CTV dose even in the presence of large intrafraction motion.

Electromagnetic methods for mapping freshwater lenses on Micronesian atoll islands

USGS Publications Warehouse

Anthony, S.S.

1992-01-01

The overall shape of freshwater lenses can be determined by applying electromagnetic methods and inverse layered-earth modeling to the mapping of atoll island freshwater lenses. Conductivity profiles were run across the width of the inhabited islands at Mwoakilloa, Pingelap, and Sapwuahfik atolls of the Pohnpei State, Federated States of Micronesia using a dual-loop, frequency-domain, electromagnetic profiling system. Six values of apparent conductivity were recorded at each sounding station and were used to interpret layer conductivities and/or thicknesses. A three-layer model that includes the unsaturated, freshwater, and saltwater zones was used to simulate apparent-conductivity data measured in the field. Interpreted results were compared with chloride-concentration data from monitoring wells and indicate that the interface between freshwater and saltwater layers, defined from electromagnetic data, is located in the upper part of the transition zone, where the chloride-concentration profile shows a rapid increase with depth. The electromagnetic method can be used to interpret the thickness of the freshwater between monitoring wells, but can not be used to interpret the thickness of freshwater from monitoring wells to the margin of an island. ?? 1992.

Transport and Non-Invasive Position Detection of Electron Beams from Laser-Plasma Accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osterhoff, J.; Nakamura, K.; Bakeman, M.

The controlled imaging and transport of ultra-relativistic electrons from laser-plasma accelerators is of crucial importance to further use of these beams, e.g. in high peak-brightness light sources. We present our plans to realize beam transport with miniature permanent quadrupole magnets from the electron source through our THUNDER undulator. Simulation results demonstrate the importance of beam imaging by investigating the generated XUV-photon flux. In addition, first experimental findings of utilizing cavity-based monitors for non-invasive beam-position measurements in a noisy electromagnetic laser-plasma environment are discussed.

Transport infrastructure surveillance and monitoring by electromagnetic sensing: the ISTIMES project.

PubMed

Proto, Monica; Bavusi, Massimo; Bernini, Romeo; Bigagli, Lorenzo; Bost, Marie; Bourquin, Frédrèric; Cottineau, Louis-Marie; Cuomo, Vincenzo; Della Vecchia, Pietro; Dolce, Mauro; Dumoulin, Jean; Eppelbaum, Lev; Fornaro, Gianfranco; Gustafsson, Mats; Hugenschmidt, Johannes; Kaspersen, Peter; Kim, Hyunwook; Lapenna, Vincenzo; Leggio, Mario; Loperte, Antonio; Mazzetti, Paolo; Moroni, Claudio; Nativi, Stefano; Nordebo, Sven; Pacini, Fabrizio; Palombo, Angelo; Pascucci, Simone; Perrone, Angela; Pignatti, Stefano; Ponzo, Felice Carlo; Rizzo, Enzo; Soldovieri, Francesco; Taillade, Fédrèric

2010-01-01

The ISTIMES project, funded by the European Commission in the frame of a joint Call "ICT and Security" of the Seventh Framework Programme, is presented and preliminary research results are discussed. The main objective of the ISTIMES project is to design, assess and promote an Information and Communication Technologies (ICT)-based system, exploiting distributed and local sensors, for non-destructive electromagnetic monitoring of critical transport infrastructures. The integration of electromagnetic technologies with new ICT information and telecommunications systems enables remotely controlled monitoring and surveillance and real time data imaging of the critical transport infrastructures. The project exploits different non-invasive imaging technologies based on electromagnetic sensing (optic fiber sensors, Synthetic Aperture Radar satellite platform based, hyperspectral spectroscopy, Infrared thermography, Ground Penetrating Radar-, low-frequency geophysical techniques, Ground based systems for displacement monitoring). In this paper, we show the preliminary results arising from the GPR and infrared thermographic measurements carried out on the Musmeci bridge in Potenza, located in a highly seismic area of the Apennine chain (Southern Italy) and representing one of the test beds of the project.

Transport Infrastructure Surveillance and Monitoring by Electromagnetic Sensing: The ISTIMES Project

PubMed Central

Proto, Monica; Bavusi, Massimo; Bernini, Romeo; Bigagli, Lorenzo; Bost, Marie; Bourquin, Frédrèric.; Cottineau, Louis-Marie; Cuomo, Vincenzo; Vecchia, Pietro Della; Dolce, Mauro; Dumoulin, Jean; Eppelbaum, Lev; Fornaro, Gianfranco; Gustafsson, Mats; Hugenschmidt, Johannes; Kaspersen, Peter; Kim, Hyunwook; Lapenna, Vincenzo; Leggio, Mario; Loperte, Antonio; Mazzetti, Paolo; Moroni, Claudio; Nativi, Stefano; Nordebo, Sven; Pacini, Fabrizio; Palombo, Angelo; Pascucci, Simone; Perrone, Angela; Pignatti, Stefano; Ponzo, Felice Carlo; Rizzo, Enzo; Soldovieri, Francesco; Taillade, Fédrèric

2010-01-01

The ISTIMES project, funded by the European Commission in the frame of a joint Call “ICT and Security” of the Seventh Framework Programme, is presented and preliminary research results are discussed. The main objective of the ISTIMES project is to design, assess and promote an Information and Communication Technologies (ICT)-based system, exploiting distributed and local sensors, for non-destructive electromagnetic monitoring of critical transport infrastructures. The integration of electromagnetic technologies with new ICT information and telecommunications systems enables remotely controlled monitoring and surveillance and real time data imaging of the critical transport infrastructures. The project exploits different non-invasive imaging technologies based on electromagnetic sensing (optic fiber sensors, Synthetic Aperture Radar satellite platform based, hyperspectral spectroscopy, Infrared thermography, Ground Penetrating Radar-, low-frequency geophysical techniques, Ground based systems for displacement monitoring). In this paper, we show the preliminary results arising from the GPR and infrared thermographic measurements carried out on the Musmeci bridge in Potenza, located in a highly seismic area of the Apennine chain (Southern Italy) and representing one of the test beds of the project. PMID:22163489

The monitoring results of electromagnetic radiation of 110-kV high-voltage lines in one urban location in Chongqing P.R. China.

PubMed

Qin, Qi-Zhong; Chen, Yu; Fu, Ting-Ting; Ding, Li; Han, Ling-Li; Li, Jian-Chao

2012-03-01

To understand electromagnetic radiation field strength and its influencing factors of certain 110-kV high-voltage lines in one urban area of Chongqing by measuring 110-kV high-voltage line's electromagnetic radiation level. According to the methodology as determined by the National Hygienic Standards, we selected certain adjacent residential buildings, high-voltage lines along a specific street and selected different distances around its vertical projection point as monitoring points. The levels of electromagnetic radiations were measured respectively. In this investigation within the frequency of 5-1,000 Hz both the electric field strength and magnetic field strength of each monitoring sites were lower than the public exposure standards as determined by the International Commission on Non-Ionizing Radiation Protection. However, the electrical field strength on the roof adjacent to the high-voltage lines was significantly higher than that as measured on the other floors in the same buildings (p < 0.05). The electromagnetic radiation measurements of different monitoring points, under the same high-voltage lines, showed the location which is nearer the high-voltage line maintain a consistently higher level of radiation than the more distant locations (p < 0.05). Electromagnetic radiation generated by high-voltage lines decreases proportionally to the distance from the lines. The buildings can to some extent shield (or absorb) the electric fields generated by high-voltage lines nearby. The electromagnetic radiation intensity near high-voltage lines may be mitigated or intensified by the manner in which the high-voltage lines are set up, and it merits attention for the potential impact on human health.

Analytical modeling and sensor monitoring for optimal processing of advanced textile structural composites by resin transfer molding

NASA Technical Reports Server (NTRS)

Loos, Alfred C.; Macrae, John D.; Hammond, Vincent H.; Kranbuehl, David E.; Hart, Sean M.; Hasko, Gregory H.; Markus, Alan M.

1993-01-01

A two-dimensional model of the resin transfer molding (RTM) process was developed which can be used to simulate the infiltration of resin into an anisotropic fibrous preform. Frequency dependent electromagnetic sensing (FDEMS) has been developed for in situ monitoring of the RTM process. Flow visualization tests were performed to obtain data which can be used to verify the sensor measurements and the model predictions. Results of the tests showed that FDEMS can accurately detect the position of the resin flow-front during mold filling, and that the model predicted flow-front patterns agreed well with the measured flow-front patterns.

Positioning and Microvibration Control by Electromagnets of an Air Spring Vibration Isolation System

NASA Technical Reports Server (NTRS)

Watanabe, Katsuhide; Cui, Weimin; Haga, Takahide; Kanemitsu, Yoichi; Yano, Kenichi

1996-01-01

Active positioning and microvibration control has been attempted by electromagnets equipped in a bellows-type, air-spring vibration isolation system. Performance tests have been carried out to study the effects. The main components of the system's isolation table were four electromagnetic actuators and controllers. The vibration isolation table was also equipped with six acceleration sensors for detecting microvibration of the table. The electromagnetic actuators were equipped with bellows-type air springs for passive support of the weight of the item placed on the table, with electromagnets for active positioning, as well as for microvibration control, and relative displacement sensors. The controller constituted a relative feedback system for positioning control and an absolute feedback system for vibration isolation control. In the performance test, a 1,490 kg load (net weight of 1,820 kg) was placed on the vibration isolation table, and both the positioning and microvibration control were carried out electromagnetically. Test results revealed that the vibration transmission was reduced by 95%.

Easily Installable Wireless Behavioral Monitoring System with Electric Field Sensor for Ordinary Houses

PubMed Central

Tsukamoto, S; Hoshino, H; Tamura, T

2008-01-01

This paper describes an indoor behavioral monitoring system for improving the quality of life in ordinary houses. It employs a device that uses weak radio waves for transmitting the obtained data and it is designed such that it can be installed by a user without requiring any technical knowledge or extra constructions. This study focuses on determining the usage statistics of home electric appliances by using an electromagnetic field sensor as a detection device. The usage of the home appliances is determined by measuring the electromagnetic field that can be observed in an area near the appliance. It is assumed that these usage statistics could provide information regarding the indoor behavior of a subject. Since the sensor is not direction sensitive and does not require precise positioning and wiring, it can be easily installed in ordinary houses by the end users. For evaluating the practicability of the sensor unit, several simple tests have been performed. The results indicate that the proposed system could be useful for collecting the usage statistics of home appliances. PMID:19415135

30 CFR 74.7 - Design and construction requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... while monitoring atmospheres including such water mists. (f) Electromagnetic interference. The CPDM shall meet the following standards for control of and protection from electromagnetic interference. (1... with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz) and 47 CFR...

30 CFR 74.7 - Design and construction requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... while monitoring atmospheres including such water mists. (f) Electromagnetic interference. The CPDM shall meet the following standards for control of and protection from electromagnetic interference. (1... with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz) and 47 CFR...

30 CFR 74.7 - Design and construction requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... while monitoring atmospheres including such water mists. (f) Electromagnetic interference. The CPDM shall meet the following standards for control of and protection from electromagnetic interference. (1... with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz) and 47 CFR...

30 CFR 74.7 - Design and construction requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... while monitoring atmospheres including such water mists. (f) Electromagnetic interference. The CPDM shall meet the following standards for control of and protection from electromagnetic interference. (1... with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz) and 47 CFR...

30 CFR 74.7 - Design and construction requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... while monitoring atmospheres including such water mists. (f) Electromagnetic interference. The CPDM shall meet the following standards for control of and protection from electromagnetic interference. (1... with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz) and 47 CFR...

Development of high resolution linear-cut beam position monitor for heavy-ion synchrotron of KHIMA project

NASA Astrophysics Data System (ADS)

Hwang, Ji-Gwang; Yang, Tae-Keun; Forck, Peter; Noh, Seon Yeong; Hahn, Garam; Choi, Minkyoo

2017-04-01

A beam position monitor with high precision and resolution is required to control the beam trajectory for matching to the injection orbit and acceleration in a heavy-ion synchrotron. It will be also used for measuring the beta function, tune, and chromaticity. Since the bunch length at heavy ion synchrotron is relatively long, a few meters, a boxlike device with plates of typically 20 cm length is used to enhance the signal strength and to get a precise linear dependence with respect to the beam displacement. Especially, the linear-cut beam position monitor is adopted to satisfy the position resolution of 100 μm and accuracy of 200 μm for a nominal beam intensity in the KHIMA synchrotron of ∼ 7 ×108 particles for the carbon beams and ∼ 2 ×1010 for the proton beams. In this paper, we show the electromagnetic design of the electrode and surroundings to satisfy the resolution of 100 μm, the criteria for mechanical aspect to satisfy the position accuracy of 200 μm, the measurement results by using wire test-bench, design and measurement of a high input impedance pre-amplifier, and the beam-test results with long (∼1.6 μs) electron beam in Pohang accelerator laboratory (PAL).

Electromagnetic pulses bone healing booster

NASA Astrophysics Data System (ADS)

Sintea, S. R.; Pomazan, V. M.; Bica, D.; Grebenisan, D.; Bordea, N.

2015-11-01

Posttraumatic bone restoration triggered by the need to assist and stimulate compensatory bone growth in periodontal condition. Recent studies state that specific electromagnetic stimulation can boost the bone restoration, reaching up to 30% decrease in recovery time. Based on the existing data on the electromagnetic parameters, a digital electronic device is proposed for intra oral mounting and bone restoration stimulation in periodontal condition. The electrical signal is applied to an inductive mark that will create and impregnate magnetic field in diseased tissue. The device also monitors the status of the electromagnetic field. Controlled wave forms and pulse frequency signal at programmable intervals are obtained with optimized number of components and miniaturized using surface mounting devices (SMD) circuits and surface mounting technology (SMT), with enhanced protection against abnormal current growth, given the intra-oral environment. The system is powered by an autonomous power supply (battery), to limit the problems caused by powering medical equipment from the main power supply. Currently the device is used in clinical testing, in cycles of six up to twelve months. Basic principles for the electrical scheme and algorithms for pulse generation, pulse control, electromagnetic field control and automation of current monitoring are presented, together with the friendly user interface, suitable for medical data and patient monitoring.

SELF and VLF electromagnetic emissions that preceded the M6.2 Central Italy earthquake occurred on August 24, 2016

NASA Astrophysics Data System (ADS)

Cataldi, Daniele; Cataldi, Gabriele; Straser, Valentino

2017-04-01

On August 24, 2016 at 01:36:32 UTC a destructive earthquake hit Central Italy with a magnitude of M6.2. The authors of this study have recorded some electromagnetic signals that have preceded this strong earthquake. These signals were recorded through two electromagnetic monitoring stations realized by Gabriele Cataldi and Daniele Cataldi, located near the town of Albano Laziale (Rome, Italy) and near the city of Lariano (Rome, Italy) and can monitor the radio spectrum 24h7 between 0.001 Hz and 96 kHz (SELF-LF band). The electromagnetic monitoring allowed to identify two interesting types of electromagnetic anomalies: the first electromagnetic anomaly was recorded on August 18, 2016 between 02:47 UTC and 06:21 UTC, in the VLF band prevalently between 18kHz and 26kHz; the second electromagnetic anomaly was registered between 08:00 UTC on August 23, 2016 and 05:00 UTC on August 24, 2016, prevalently between 0.01 and 0.7Hz: the most intense signals were recorded at 08:50 UTC on August 23, 2016 and approximately 1 hour before the strong earthquake. The Earth's electromagnetic background monitoring in the SELF-VLF band (0Hz

Electromagnetic Interference of Wireless Local Area Network on Electrocardiogram Monitoring System: A Case Report

PubMed Central

Chung, Seungmin; Yi, Joohee

2013-01-01

Electromagnetic interference (EMI) can affect various medical devices. Herein, we report the case of EMI from wireless local area network (WLAN) on an electrocardiogram (ECG) monitoring system. A patient who had a prior myocardial infarction participated in the cardiac rehabilitation program in the sports medicine center of our hospital under the wireless ECG monitoring system. After WLAN was installed, wireless ECG monitoring system failed to show a proper ECG signal. ECG signal was distorted when WLAN was turned on, but it was normalized after turning off the WLAN. PMID:23613696

Estimation of the Lithospheric Component Share in the Earth Natural Pulsed Electromagnetic Field Structure

NASA Astrophysics Data System (ADS)

Malyshkov, S. Y.; Gordeev, V. F.; Polyvach, V. I.; Shtalin, S. G.; Pustovalov, K. N.

2017-04-01

Article describes the results of the atmosphere and Earth’s crust climatic and ecological parameters integrated monitoring. The estimation is made for lithospheric component share in the Earth natural pulsed electromagnetic field structure. To estimate lithospheric component we performed a round-the-clock monitoring of the Earth natural pulsed electromagnetic field background variations at the experiment location and measured the Earth natural pulsed electromagnetic field under electric shields. Natural materials in a natural environment were used for shielding, specifically lakes with varying parameters of water conductivity. Skin effect was used in the experiment - it is the tendency of electromagnetic waves amplitude to decrease with greater depths in the conductor. Atmospheric and lithospheric component the Earth natural pulsed electromagnetic field data recorded on terrain was compared against the recorded data with atmosphere component decayed by an electric shield. In summary we have demonstrated in the experiment that thunderstorm discharge originating electromagnetic field decay corresponds to the decay calculated using Maxwell equations. In the absence of close lightning strikes the ratio of field intensity recorded on terrain to shielded field intensity is inconsistent with the ratio calculated for atmospheric sources, that confirms there is a lithospheric component present to the Earth natural pulsed electromagnetic field.

Noninvasive valve monitor using constant magnetic and/or DC electromagnetic field

DOEpatents

Casada, D.A.; Haynes, H.D.

1993-08-17

One or more sources of steady magnetic field are carefully located on the outside of a valve body. The constant magnetic field is transmitted into the valve body and valve internals. A magnetic field detector carefully located on the outside of the valve body detects the intensity of the magnetic field at its location. As the position of a valve internal part is changed, there is an alteration in the magnetic field in the valve, and a consequent change in the detected magnetic field. Changes in the detected signal provide an indication of the position and motion of the valve internals.

Noninvasive valve monitor using constant magnetic and/or DC electromagnetic field

DOEpatents

Casada, Donald A.; Haynes, Howard D.

1993-01-01

One or more sources of steady magnetic field are carefully located on the outside of a valve body. The constant magnetic field is transmitted into the valve body and valve internals. A magnetic field detector carefully located on the outside of the valve body detects the intensity of the magnetic field at its location. As the position of a valve internal part is changed, there is an alteration in the magnetic field in the valve, and a consequent change in the detected magnetic field. Changes in the detected signal provide an indication of the position and motion of the valve internals.

Beam feasibility study of a collimator with in-jaw beam position monitors

NASA Astrophysics Data System (ADS)

Wollmann, Daniel; Nosych, Andriy A.; Valentino, Gianluca; Aberle, Oliver; Aßmann, Ralph W.; Bertarelli, Alessandro; Boccard, Christian; Bruce, Roderik; Burkart, Florian; Calvo, Eva; Cauchi, Marija; Dallocchio, Alessandro; Deboy, Daniel; Gasior, Marek; Jones, Rhodri; Kain, Verena; Lari, Luisella; Redaelli, Stefano; Rossi, Adriana

2014-12-01

At present, the beam-based alignment of the LHC collimators is performed by touching the beam halo with both jaws of each collimator. This method requires dedicated fills at low intensities that are done infrequently and makes this procedure time consuming. This limits the operational flexibility, in particular in the case of changes of optics and orbit configuration in the experimental regions. The performance of the LHC collimation system relies on the machine reproducibility and regular loss maps to validate the settings of the collimator jaws. To overcome these limitations and to allow a continuous monitoring of the beam position at the collimators, a design with jaw-integrated Beam Position Monitors (BPMs) was proposed and successfully tested with a prototype (mock-up) collimator in the CERN SPS. Extensive beam experiments allowed to determine the achievable accuracy of the jaw alignment for single and multi-turn operation. In this paper, the results of these experiments are discussed. The non-linear response of the BPMs is compared to the predictions from electromagnetic simulations. Finally, the measured alignment accuracy is compared to the one achieved with the present collimators in the LHC.

Illumination system having a plurality of movable sources

DOEpatents

Sweatt, William C.; Kubiak, Glenn D.

2002-01-01

An illumination system includes several discharge sources that are multiplexed together to reduce the amount of debris generated. The system includes: (a) a first electromagnetic radiation source array that includes a plurality of first activatable radiation source elements that are positioned on a first movable carriage; (b) a second electromagnetic radiation source array that includes a plurality of second activatable radiation source elements that are positioned on a second movable carriage; (c) means for directing electromagnetic radiation from the first electromagnetic radiation source array and electromagnetic radiation from the second electromagnetic radiation source array toward a common optical path; (d) means for synchronizing (i) the movements of the first movable carriage and of the second movable carriage and (ii) the activation of the first electromagnetic radiation source array and of the second electromagnetic radiation source array to provide an essentially continuous illumination of electromagnetic radiation along the common optical path.

A novel electromagnetic design and a new manufacturing process for the cavity BPM (Beam Position Monitor)

NASA Astrophysics Data System (ADS)

Dal Forno, Massimo; Craievich, Paolo; Baruzzo, Roberto; De Monte, Raffaele; Ferianis, Mario; Lamanna, Giuseppe; Vescovo, Roberto

2012-01-01

The Cavity Beam Position Monitor (BPM) is a beam diagnostic instrument which, in a seeded Free Electron Laser (FEL), allows the measurement of the electron beam position in a non-destructive way and with sub-micron resolution. It is composed by two resonant cavities called reference and position cavity, respectively. The measurement exploits the dipole mode that arises when the electron bunch passes off axis. In this paper we describe the Cavity BPM that has been designed and realized in the context of the FERMI@Elettra project [1]. New strategies have been adopted for the microwave design, for both the reference and the position cavities. Both cavities have been simulated by means of Ansoft HFSS [2] and CST Particle Studio [3], and have been realized using high precision lathe and wire-EDM (Electro-Discharge) machine, with a new technique that avoids the use of the sinker-EDM machine. Tuners have been used to accurately adjust the working frequencies for both cavities. The RF parameters have been estimated, and the modifications of the resonant frequencies produced by brazing and tuning have been evaluated. Finally, the Cavity BPM has been installed and tested in the presence of the electron beam.

Weather radar performance monitoring using a metallic-grid ground-scatterer

NASA Astrophysics Data System (ADS)

Falconi, Marta Tecla; Montopoli, Mario; Marzano, Frank Silvio; Baldini, Luca

2017-10-01

The use of ground return signals is investigated for checks on the calibration of power measurements of a polarimetric C-band radar. To this aim, a peculiar permanent single scatterer (PSS) consisting of a big metallic roof with a periodic mesh grid structure and having a hemisphere-like shape is considered. The latter is positioned in the near-field region of the weather radar and its use, as a reference calibrator, shows fairly good results in terms of reflectivity and differential reflectivity monitoring. In addition, the use of PSS indirectly allows to check for the radar antenna de-pointing which is another issue usually underestimated when dealing with weather radars. Because of the periodic structure of the considered PSS, simulations of its electromagnetic behavior were relatively easy to perform. To this goal, we used an electromagnetic Computer-Aided-Design (CAD) with an ad-hoc numerical implementation of a full-wave solution to model our PSS in terms of reflectivity and differential reflectivity factor. Comparison of model results and experimental measurements are then shown in this work. Our preliminary investigation can pave the way for future studies aiming at characterizing ground-clutter returns in a more accurate way for radar calibration purposes.

A Cognitive Agent for Spectrum Monitoring and Informed Spectrum Access

DTIC Science & Technology

2017-06-01

electromagnetic environments (EMEs) to understand what spectrum bands are accessed, when those bands are accessed, and how much energy is...recall. The cognitive agent in this report uses the second approach. The knowledge domain of the cognitive agent is the electromagnetic spectrum. The...Knowledge DTV digital television EME electromagnetic environments FM frequency modulated RF radio frequency VHF very high frequency

The impact of electromagnetic radiation of different parameters on platelet oxygen metabolism - in vitro studies.

PubMed

Lewicka, Małgorzata; Henrykowska, Gabriela A; Pacholski, Krzysztof; Szczęsny, Artur; Dziedziczak-Buczyńska, Maria; Buczyński, Andrzej

2015-01-01

Electromagnetic radiation emitted by a variety of devices, e.g. cell phones, computers and microwaves, interacts with the human body in many ways. Research studies carried out in the last few decades have not yet resolved the issue of the effect of this factor on the human body and many questions are left without an unequivocal answer. Various biological and health-related effects have not been fully recognized. Thus further studies in this area are justified. A comparison of changes within catalase enzymatic activity and malondialdehyde concentration arising under the influence of the electromagnetic radiation emitted by car electronics, equipment used in physiotherapy and LCD monitors. The suspension of human blood platelets at a concentration of 1 × 109/0.001 dm 3, obtained from whole blood by manual apheresis, was the study material. Blood platelets were exposed to an electromagnetic field for 30 min in a laboratory stand designed for the reconstruction of the electromagnetic radiation generated by car electronics, physiotherapy equipment and LCD monitors. The changes in catalase activity and malondialdehyde concentration were investigated after the exposure and compared to the control values (unexposed material). An increase in catalase activity and malondialdehyde concentration was observed after 30 min exposure of platelets to EMF regardless of the radiation source. The most significant changes determining the degree of oxidative stress were observed after exposure to the EMF generated by car electronics. The low frequency electromagnetic fields generated by car electronics, physiotherapy equipment and LCD monitors may be a cause of oxidative stress in the human body and may lead to free radical diseases.

Acoustic Nondestructive Evaluation of Aircraft Paneling Using Piezoelectric Sensors

DTIC Science & Technology

2012-12-01

Electromagnetic Materials Team of the U.S. Army Research Laboratory, Weapons and Materials Research Directorate, Clinical Trials Monitoring Branch, for...connected to this clip. This electrical connection ensures single-point grounding, which has been implemented to avoid electromagnetic interference...waveform of each sensor features an electromagnetic pick-up signature that is aligned with the transduced signal but phase shifted by 180. We know to

Formulation of a strategy for monitoring control integrity in critical digital control systems

NASA Technical Reports Server (NTRS)

Belcastro, Celeste M.; Fischl, Robert; Kam, Moshe

1991-01-01

Advanced aircraft will require flight critical computer systems for stability augmentation as well as guidance and control that must perform reliably in adverse, as well as nominal, operating environments. Digital system upset is a functional error mode that can occur in electromagnetically harsh environments, involves no component damage, can occur simultaneously in all channels of a redundant control computer, and is software dependent. A strategy is presented for dynamic upset detection to be used in the evaluation of critical digital controllers during the design and/or validation phases of development. Critical controllers must be able to be used in adverse environments that result from disturbances caused by an electromagnetic source such as lightning, high intensity radiated field (HIRF), and nuclear electromagnetic pulses (NEMP). The upset detection strategy presented provides dynamic monitoring of a given control computer for degraded functional integrity that can result from redundancy management errors and control command calculation error that could occur in an electromagnetically harsh operating environment. The use is discussed of Kalman filtering, data fusion, and decision theory in monitoring a given digital controller for control calculation errors, redundancy management errors, and control effectiveness.

Electromagnetic interference may cause false asystole alarms in certain Philips IntelliVue monitoring products.

PubMed

2011-09-01

Electromagnetic interference (EMI) may cause some Philips Healthcare IntelliVue MMS, MP2, MP5, and X2 patient monitoring products to incorrectly display a flat electrocardiogram (ECG) waveform and generate a false asystole alarm. This occurs while the devices' pace pulse rejection feature is enabled. Facilities that suspect such behavior in their inventories should contact Philips to discuss whether installation of firmware version D.02.05 will help address the problem.

Can electromagnetic-navigated maxillary positioning replace occlusional splints in orthognathic surgery? A clinical pilot study.

PubMed

Berger, Moritz; Nova, Igor; Kallus, Sebastian; Ristow, Oliver; Freudlsperger, Christian; Eisenmann, Urs; Dickhaus, Hartmut; Engel, Michael; Hoffmann, Jürgen; Seeberger, Robin

2017-10-01

Because of the inaccuracy of intermaxillary splints in orthognathic surgery, intraoperative guidance via a real time navigation system might represent a suitable method for enhancing the precision of maxillary positioning. Therefore, in this clinical trial, maxillary repositioning after Le Fort I osteotomy was guided splintless by an electromagnetic navigation system. Conservatively planned maxillary reposition in each of 5 patients was transferred to a novel software module of the electromagnetic navigation system. Intraoperatively, after Le Fort I osteotomy, the software guided the maxilla to the targeted position. Accuracy was evaluated by pre- and postoperative cone beam computer tomography imaging (the vectorial distance of the incisal marker points was measured in three dimensions) and compared with that of a splint transposed control group. The repositioning of the maxilla guided by the electromagnetic navigation system was intuitive and simple to accomplish. The achieved maxillary position with a deviation of 0.7 mm on average to the planned position was equally accurate compared with that of the splint transposed control group of 0.5 mm (p > 0.05). The data of this clinical study display good accuracy for splintless electromagnetic-navigated maxillary positioning. Nevertheless, this method does not surpass the splint-encoded gold standard with regard to accuracy. Future investigations will be necessary to show the full potential of electromagnetic navigation in orthognathic surgery. Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Non-latching relay switch assembly

DOEpatents

Duimstra, Frederick A.

1991-01-01

A non-latching relay switch assembly which includes a coil section and a switch or contact section. The coil section includes a permanent magnet and an electromagnet. The respective sections are arranged in separate locations or cavities in the assembly. The switch has a "normal" position and is selectively switched by an overriding electromagnetic assembly. The switch returns to the "normal" position when the overriding electromagnetic assembly is inactive.

A bronchoscopic navigation system using bronchoscope center calibration for accurate registration of electromagnetic tracker and CT volume without markers.

PubMed

Luo, Xiongbiao

2014-06-01

Various bronchoscopic navigation systems are developed for diagnosis, staging, and treatment of lung and bronchus cancers. To construct electromagnetically navigated bronchoscopy systems, registration of preoperative images and an electromagnetic tracker must be performed. This paper proposes a new marker-free registration method, which uses the centerlines of the bronchial tree and the center of a bronchoscope tip where an electromagnetic sensor is attached, to align preoperative images and electromagnetic tracker systems. The chest computed tomography (CT) volume (preoperative images) was segmented to extract the bronchial centerlines. An electromagnetic sensor was fixed at the bronchoscope tip surface. A model was designed and printed using a 3D printer to calibrate the relationship between the fixed sensor and the bronchoscope tip center. For each sensor measurement that includes sensor position and orientation information, its corresponding bronchoscope tip center position was calculated. By minimizing the distance between each bronchoscope tip center position and the bronchial centerlines, the spatial alignment of the electromagnetic tracker system and the CT volume was determined. After obtaining the spatial alignment, an electromagnetic navigation bronchoscopy system was established to real-timely track or locate a bronchoscope inside the bronchial tree during bronchoscopic examinations. The electromagnetic navigation bronchoscopy system was validated on a dynamic bronchial phantom that can simulate respiratory motion with a breath rate range of 0-10 min(-1). The fiducial and target registration errors of this navigation system were evaluated. The average fiducial registration error was reduced from 8.7 to 6.6 mm. The average target registration error, which indicates all tracked or navigated bronchoscope position accuracy, was much reduced from 6.8 to 4.5 mm compared to previous registration methods. An electromagnetically navigated bronchoscopy system was constructed with accurate registration of an electromagnetic tracker and the CT volume on the basis of an improved marker-free registration approach that uses the bronchial centerlines and bronchoscope tip center information. The fiducial and target registration errors of our electromagnetic navigation system were about 6.6 and 4.5 mm in dynamic bronchial phantom validation.

A bronchoscopic navigation system using bronchoscope center calibration for accurate registration of electromagnetic tracker and CT volume without markers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, Xiongbiao, E-mail: xiongbiao.luo@gmail.com

2014-06-15

Purpose: Various bronchoscopic navigation systems are developed for diagnosis, staging, and treatment of lung and bronchus cancers. To construct electromagnetically navigated bronchoscopy systems, registration of preoperative images and an electromagnetic tracker must be performed. This paper proposes a new marker-free registration method, which uses the centerlines of the bronchial tree and the center of a bronchoscope tip where an electromagnetic sensor is attached, to align preoperative images and electromagnetic tracker systems. Methods: The chest computed tomography (CT) volume (preoperative images) was segmented to extract the bronchial centerlines. An electromagnetic sensor was fixed at the bronchoscope tip surface. A model wasmore » designed and printed using a 3D printer to calibrate the relationship between the fixed sensor and the bronchoscope tip center. For each sensor measurement that includes sensor position and orientation information, its corresponding bronchoscope tip center position was calculated. By minimizing the distance between each bronchoscope tip center position and the bronchial centerlines, the spatial alignment of the electromagnetic tracker system and the CT volume was determined. After obtaining the spatial alignment, an electromagnetic navigation bronchoscopy system was established to real-timely track or locate a bronchoscope inside the bronchial tree during bronchoscopic examinations. Results: The electromagnetic navigation bronchoscopy system was validated on a dynamic bronchial phantom that can simulate respiratory motion with a breath rate range of 0–10 min{sup −1}. The fiducial and target registration errors of this navigation system were evaluated. The average fiducial registration error was reduced from 8.7 to 6.6 mm. The average target registration error, which indicates all tracked or navigated bronchoscope position accuracy, was much reduced from 6.8 to 4.5 mm compared to previous registration methods. Conclusions: An electromagnetically navigated bronchoscopy system was constructed with accurate registration of an electromagnetic tracker and the CT volume on the basis of an improved marker-free registration approach that uses the bronchial centerlines and bronchoscope tip center information. The fiducial and target registration errors of our electromagnetic navigation system were about 6.6 and 4.5 mm in dynamic bronchial phantom validation.« less

Monitoring of ULF (ultra-low-frequency) Geomagnetic Variations Associated with Earthquakes

PubMed Central

Hayakawa, Masashi; Hattori, Katsumi; Ohta, Kenji

2007-01-01

ULF (ultra-low-frequency) electromagnetic emission is recently recognized as one of the most promising candidates for short-term earthquake prediction. This paper reviews previous convincing evidence on the presence of ULF emissions before a few large earthquakes. Then, we present our network of ULF monitoring in the Tokyo area by describing our ULF magnetic sensors and we finally present a few, latest results on seismogenic electromagnetic emissions for recent large earthquakes with the use of sophisticated signal processings.

Monitoring cure of composite resins using frequency dependent electromagnetic sensing techniques

NASA Technical Reports Server (NTRS)

Kranbuehl, D. E.; Hoff, M. S.; Loos, A. C.; Freeman, W. T., Jr.; Eichinger, D. A.

1988-01-01

A nondestructive in situ measurement technique has been developed for monitoring and measuring the cure processing properties of composite resins. Frequency dependent electromagnetic sensors (FDEMS) were used to directly measure resin viscosity during cure. The effects of the cure cycle and resin aging on the viscosity during cure were investigated using the sensor. Viscosity measurements obtained using the sensor are compared with the viscosities calculated by the Loos-Springer cure process model. Good overall agreement was obtained except for the aged resin samples.

Monitoring relative humidity in RPC detectors by use of fiber optic sensors

NASA Astrophysics Data System (ADS)

Caponero, M. A.; Polimadei, A.; Benussi, L.; Bianco, S.; Colafranceschi, S.; Passamonti, L.; Piccolo, D.; Pierluigi, D.; Russo, A.; Felli, F.; Saviano, G.; Vendittozzi, C.

2013-03-01

We propose to adopt Fiber Bragg Grating technology to develop an innovative sensor for monitoring relative humidity of the gas fluxed in Resistive Plate Counters. Use of Fiber Bragg Grating as sensing device makes the proposed sensor well suited to develop distributed real-time monitoring systems to be installed on large volume detectors operated in high electromagnetic fields. In fact Fiber Bragg Gratings are fully immune from electromagnetic disturbances and allow simplified wiring by in-series interconnection of tens of them along a single optical fiber. In this paper we present results intended to investigate the feasibility of our proposal.

Portable Electromagnetic Induction Sensor with Integrated Positioning

DTIC Science & Technology

2013-08-20

Subsurface electromagnetic induction imaging for unexploded ordnance detection. Journal of Applied Geophysics, 79:38 – 45, 2012. ISSN 09269851. URL http...Portable Electromagnetic Induction Sensor with Integrated Positioning MR-1712 Final Report Submitted to Strategic Environmental Research and...19a. NAME OF RESPONSIBLE PERSON 19b. TELEPHONE NUMBER (include area code) Standard Form 298 (Rev. 8–98) Prescribed by ANSI Std. Z39.18 06–25–2013

EUV phase-shifting masks and aberration monitors

NASA Astrophysics Data System (ADS)

Deng, Yunfei; Neureuther, Andrew R.

2002-07-01

Rigorous electromagnetic simulation with TEMPEST is used to examine the use of phase-shifting masks in EUV lithography. The effects of oblique incident illumination and mask patterning by ion-mixing of multilayers are analyzed. Oblique incident illumination causes streamers at absorber edges and causes position shifting in aerial images. The diffraction waves between ion-mixed and pristine multilayers are observed. The phase-shifting caused by stepped substrates is simulated and images show that it succeeds in creation of phase-shifting effects. The diffraction process at the phase boundary is also analyzed. As an example of EUV phase-shifting masks, a coma pattern and probe based aberration monitor is simulated and aerial images are formed under different levels of coma aberration. The probe signal rises quickly as coma increases as designed.

Rockburst Disaster Prediction of Isolated Coal Pillar by Electromagnetic Radiation Based on Frictional Effect

PubMed Central

Zhao, Tongbin; Yin, Yanchun; Xiao, Fukun; Tan, Yunliang; Zou, Jianchao

2014-01-01

Based on the understanding that charges generated during coal cracking are due to coal particle friction, a microstructure model was developed by considering four different variation laws of friction coefficient. Firstly, the frictional energy release of coal sample during uniaxial compressive tests was investigated and discussed. Then electromagnetic radiation method was used to predict the potential rockburst disaster in isolated coal pillar mining face, Muchengjian Colliery. The results indicate that the friction coefficient of coal particles decreases linearly with the increase of axial loading force. In predicting the strain-type rockburst, the high stress state of coal must be closely monitored. Field monitoring shows that electromagnetic radiation signal became abnormal before the occurrence of rockburst during isolated coal pillar mining. Furthermore, rockburst tends to occur at the early and ending stages of isolated coal pillar extraction. Mine-site investigation shows the occurrence zone of rockburst is consistent with the prediction, proving the reliability of the electromagnetic radiation method to predict strain-type rockburst disaster. PMID:25054186

Rockburst disaster prediction of isolated coal pillar by electromagnetic radiation based on frictional effect.

PubMed

Zhao, Tongbin; Yin, Yanchun; Xiao, Fukun; Tan, Yunliang; Zou, Jianchao

2014-01-01

Based on the understanding that charges generated during coal cracking are due to coal particle friction, a microstructure model was developed by considering four different variation laws of friction coefficient. Firstly, the frictional energy release of coal sample during uniaxial compressive tests was investigated and discussed. Then electromagnetic radiation method was used to predict the potential rockburst disaster in isolated coal pillar mining face, Muchengjian Colliery. The results indicate that the friction coefficient of coal particles decreases linearly with the increase of axial loading force. In predicting the strain-type rockburst, the high stress state of coal must be closely monitored. Field monitoring shows that electromagnetic radiation signal became abnormal before the occurrence of rockburst during isolated coal pillar mining. Furthermore, rockburst tends to occur at the early and ending stages of isolated coal pillar extraction. Mine-site investigation shows the occurrence zone of rockburst is consistent with the prediction, proving the reliability of the electromagnetic radiation method to predict strain-type rockburst disaster.

Development and program implementation of elements for identification of the electromagnet condition for movable element position control

NASA Astrophysics Data System (ADS)

Leukhin, R. I.; Shaykhutdinov, D. V.; Shirokov, K. M.; Narakidze, N. D.; Vlasov, A. S.

2017-02-01

Developing the experimental design of new electromagnetic constructions types in engineering industry enterprises requires solutions of two major problems: regulator’s parameters setup and comprehensive testing of electromagnets. A weber-ampere characteristic as a data source for electromagnet condition identification was selected. Present article focuses on development and implementation of the software for electromagnetic drive control system based on the weber-ampere characteristic measuring. The software for weber-ampere characteristic data processing based on artificial neural network is developed. Results of the design have been integrated into the program code in LabVIEW environment. The license package of LabVIEW graphic programming was used. The hardware is chosen and possibility of its use for control system implementation was proved. The trained artificial neural network defines electromagnetic drive effector position with minimal error. Developed system allows to control the electromagnetic drive powered by the voltage source, the current source and hybrid sources.

Results of time-domain electromagnetic soundings in Miami-Dade and southern Broward Counties, Florida

USGS Publications Warehouse

Fitterman, David V.; Prinos, Scott T.

2011-01-01

Time-domain electromagnetic (TEM) soundings were made in Miami-Dade and southern Broward Counties to aid in mapping the landward extent of saltwater in the Biscayne aquifer. A total of 79 soundings were collected in settings ranging from urban to undeveloped land, with some of the former posing problems of land access and interference from anthropogenic features. TEM soundings combined with monitoring-well data were used to determine if the saltwater front had moved since the last time it was mapped, to provide additional spatial coverage where existing monitoring wells were insufficient, and to help interpret a previously collected helicopter electromagnetic (HEM) survey flown in the southernmost portion of the study area. TEM soundings were interpreted as layered resistivity-depth models. Using information from well logs and water-quality data, the resistivity of the freshwater saturated Biscayne aquifer is expected to be above 30 ohm-meters, and the saltwater-saturated aquifer will have resistivities of less than 10 ohm-meters allowing determination of water quality from the TEM interpretations. TEM models from 29 soundings were compared to electromagnetic induction logs collected in nearby monitoring wells. In general, the agreement of these results was very good, giving confidence in the use of the TEM data for mapping saltwater encroachment.

Descriptive study of electromagnetic wave distribution for various seating positions: using digital textbooks.

PubMed

Seomun, GyeongAe; Kim, YoungHwan; Lee, Jung-Ah; Jeong, KwangHoon; Park, Seon-A; Kim, Miran; Noh, Wonjung

2014-04-01

To better understand environmental electromagnetic wave exposure during the use of digital textbooks by elementary school students, we measured numeric values of the electromagnetic fields produced by tablet personal computers (TPCs). Specifically, we examined the distribution of the electromagnetic waves for various students' seating positions in an elementary school that uses digital textbooks. Electric and magnetic fields from TPCs were measured using the HI-3603 Visual Display Terminal/ Very Low Frequency (VDT/VLF) radiation measurement system. Electromagnetic field values from TPCs measured at a student's seat and at a teacher's computer were deemed not harmful to health. However, electromagnetic field values varied based on the distance between students, other electronic devices such as a desktop computers, and student posture while using a TPC. Based on these results, it is necessary to guide students to observe proper posture and to arrange seats at an appropriate distance in the classroom.

Spiral passive electromagnetic sensor (SPES) for smart sensing and de-icing

NASA Astrophysics Data System (ADS)

Iervolino, Onorio; Meo, Michele

2015-04-01

The objective of this work was to develop a wireless Spiral Passive Electromagnetic Sensor (SPES) to monitor the complex permittivity of a surrounding medium. The sensor is a self-resonating planar pattern of electrically conductive material. Investigation were conducted to demonstrate the capability of the SPES to monitor humidity and temperature gradients, and acting as an ice protection tool. An oscillating signal is used to interrogate remotely the sensor with a single loop antenna or wiring it directly to a spectrum analyser and monitoring the backscattering signal. The excited sensor responds with its own resonant frequency, amplitude and bandwidth that can be correlated to physical quantities to be monitored. Our studies showed the capability of the sensor to monitor temperature and humidity changes in composite materials and uniformly produce induction heating when the conductive path is activated by an external electric power supply that can be used for deicing of aircraft structures.

Remote monitoring of electromagnetic signals and seismic events using smart mobile devices

NASA Astrophysics Data System (ADS)

Georgiadis, Pantelis; Cavouras, Dionisis; Sidiropoulos, Konstantinos; Ninos, Konstantinos; Nomicos, Constantine

2009-06-01

This study presents the design and development of a novel mobile wireless system to be used for monitoring seismic events and related electromagnetic signals, employing smart mobile devices like personal digital assistants (PDAs) and wireless communication technologies such as wireless local area networks (WLANs), general packet radio service (GPRS) and universal mobile telecommunications system (UMTS). The proposed system enables scientists to access critical data while being geographically independent of the sites of data sources, rendering it as a useful tool for preliminary scientific analysis.

The first clinical implementation of electromagnetic transponder-guided MLC tracking.

PubMed

Keall, Paul J; Colvill, Emma; O'Brien, Ricky; Ng, Jin Aun; Poulsen, Per Rugaard; Eade, Thomas; Kneebone, Andrew; Booth, Jeremy T

2014-02-01

We report on the clinical process, quality assurance, and geometric and dosimetric results of the first clinical implementation of electromagnetic transponder-guided MLC tracking which occurred on 28 November 2013 at the Northern Sydney Cancer Centre. An electromagnetic transponder-based positioning system (Calypso) was modified to send the target position output to in-house-developed MLC tracking code, which adjusts the leaf positions to optimally align the treatment beam with the real-time target position. Clinical process and quality assurance procedures were developed and performed. The first clinical implementation of electromagnetic transponder-guided MLC tracking was for a prostate cancer patient being treated with dual-arc VMAT (RapidArc). For the first fraction of the first patient treatment of electromagnetic transponder-guided MLC tracking we recorded the in-room time and transponder positions, and performed dose reconstruction to estimate the delivered dose and also the dose received had MLC tracking not been used. The total in-room time was 21 min with 2 min of beam delivery. No additional time was needed for MLC tracking and there were no beam holds. The average prostate position from the initial setup was 1.2 mm, mostly an anterior shift. Dose reconstruction analysis of the delivered dose with MLC tracking showed similar isodose and target dose volume histograms to the planned treatment and a 4.6% increase in the fractional rectal V60. Dose reconstruction without motion compensation showed a 30% increase in the fractional rectal V60 from that planned, even for the small motion. The real-time beam-target correction method, electromagnetic transponder-guided MLC tracking, has been translated to the clinic. This achievement represents a milestone in improving geometric and dosimetric accuracy, and by inference treatment outcomes, in cancer radiotherapy.

The first clinical implementation of electromagnetic transponder-guided MLC tracking

PubMed Central

Keall, Paul J.; Colvill, Emma; O’Brien, Ricky; Ng, Jin Aun; Poulsen, Per Rugaard; Eade, Thomas; Kneebone, Andrew; Booth, Jeremy T.

2014-01-01

Purpose: We report on the clinical process, quality assurance, and geometric and dosimetric results of the first clinical implementation of electromagnetic transponder-guided MLC tracking which occurred on 28 November 2013 at the Northern Sydney Cancer Centre. Methods: An electromagnetic transponder-based positioning system (Calypso) was modified to send the target position output to in-house-developed MLC tracking code, which adjusts the leaf positions to optimally align the treatment beam with the real-time target position. Clinical process and quality assurance procedures were developed and performed. The first clinical implementation of electromagnetic transponder-guided MLC tracking was for a prostate cancer patient being treated with dual-arc VMAT (RapidArc). For the first fraction of the first patient treatment of electromagnetic transponder-guided MLC tracking we recorded the in-room time and transponder positions, and performed dose reconstruction to estimate the delivered dose and also the dose received had MLC tracking not been used. Results: The total in-room time was 21 min with 2 min of beam delivery. No additional time was needed for MLC tracking and there were no beam holds. The average prostate position from the initial setup was 1.2 mm, mostly an anterior shift. Dose reconstruction analysis of the delivered dose with MLC tracking showed similar isodose and target dose volume histograms to the planned treatment and a 4.6% increase in the fractional rectal V60. Dose reconstruction without motion compensation showed a 30% increase in the fractional rectal V60 from that planned, even for the small motion. Conclusions: The real-time beam-target correction method, electromagnetic transponder-guided MLC tracking, has been translated to the clinic. This achievement represents a milestone in improving geometric and dosimetric accuracy, and by inference treatment outcomes, in cancer radiotherapy. PMID:24506591

Detecting the position of the moving-iron solenoid by non-displacement sensor based on parameter identification of flux linkage characteristics

NASA Astrophysics Data System (ADS)

Wang, Xuping; Quan, Long; Xiong, Guangyu

2013-11-01

Currently, most researches use signals, such as the coil current or voltage of solenoid, to identify parameters; typically, parameter identification method based on variation rate of coil current is applied for position estimation. The problem exists in these researches that the detected signals are prone to interference and difficult to obtain. This paper proposes a new method for detecting the core position by using flux characteristic quantity, which adds a new group of secondary winding to the coil of the ordinary switching electromagnet. On the basis of electromagnetic coupling theory analysis and simulation research of the magnetic field regarding the primary and secondary winding coils, and in accordance with the fact that under PWM control mode varying core position and operating current of windings produce different characteristic of flux increment of the secondary winding. The flux increment of the electromagnet winding can be obtained by conducting time domain integration for the induced voltage signal of the extracted secondary winding, and the core position from the two-dimensional fitting curve of the operating winding current and flux-linkage characteristic quantity of solenoid are calculated. The detecting and testing system of solenoid core position is developed based on the theoretical research. The testing results show that the flux characteristic quantity of switching electromagnet magnetic circuit is able to effectively show the core position and thus to accomplish the non-displacement transducer detection of the said core position of the switching electromagnet. This paper proposes a new method for detecting the core position by using flux characteristic quantity, which provides a new theory and method for switch solenoid to control the proportional valve.

A Determination of the Risk of Intentional and Unintentional Electromagnetic Radiation Emitters Degrading Installed Components in Closed Electromagnetic Environments

DTIC Science & Technology

2015-06-01

shield that tends to lower the EM levels at the surface of the Earth (Christopoulos 2007). It is important to note for the purposes of this paper...ELECTROMAGNETIC ENVIRONMENTS 5. FUNDING NUMBERS 6. AUTHOR( S ) Jared A. Johnson 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) Naval Postgraduate School...Monterey, CA 93943-5000 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING /MONITORING AGENCY NAME( S ) AND ADDRESS(ES) N/A 10. SPONSORING

Channel Measurements for Automatic Vehicle Monitoring Systems

DOT National Transportation Integrated Search

1974-03-01

Co-channel and adjacent channel electromagnetic interference measurements were conducted on the Sierra Research Corp. and the Chicago Transit Authority automatic vehicle monitoring systems. These measurements were made to determine if the automatic v...

Real-Time Two-Dimensional Magnetic Particle Imaging for Electromagnetic Navigation in Targeted Drug Delivery.

PubMed

Le, Tuan-Anh; Zhang, Xingming; Hoshiar, Ali Kafash; Yoon, Jungwon

2017-09-07

Magnetic nanoparticles (MNPs) are effective drug carriers. By using electromagnetic actuated systems, MNPs can be controlled noninvasively in a vascular network for targeted drug delivery (TDD). Although drugs can reach their target location through capturing schemes of MNPs by permanent magnets, drugs delivered to non-target regions can affect healthy tissues and cause undesirable side effects. Real-time monitoring of MNPs can improve the targeting efficiency of TDD systems. In this paper, a two-dimensional (2D) real-time monitoring scheme has been developed for an MNP guidance system. Resovist particles 45 to 65 nm in diameter (5 nm core) can be monitored in real-time (update rate = 2 Hz) in 2D. The proposed 2D monitoring system allows dynamic tracking of MNPs during TDD and renders magnetic particle imaging-based navigation more feasible.

Real-Time Two-Dimensional Magnetic Particle Imaging for Electromagnetic Navigation in Targeted Drug Delivery

PubMed Central

Le, Tuan-Anh; Zhang, Xingming; Hoshiar, Ali Kafash; Yoon, Jungwon

2017-01-01

Magnetic nanoparticles (MNPs) are effective drug carriers. By using electromagnetic actuated systems, MNPs can be controlled noninvasively in a vascular network for targeted drug delivery (TDD). Although drugs can reach their target location through capturing schemes of MNPs by permanent magnets, drugs delivered to non-target regions can affect healthy tissues and cause undesirable side effects. Real-time monitoring of MNPs can improve the targeting efficiency of TDD systems. In this paper, a two-dimensional (2D) real-time monitoring scheme has been developed for an MNP guidance system. Resovist particles 45 to 65 nm in diameter (5 nm core) can be monitored in real-time (update rate = 2 Hz) in 2D. The proposed 2D monitoring system allows dynamic tracking of MNPs during TDD and renders magnetic particle imaging-based navigation more feasible. PMID:28880220

Method and apparatus for sensing a target characteristic by measuring both impedance and resonant frequency of a tank circuit

NASA Technical Reports Server (NTRS)

Laskowski, Edward L. (Inventor)

1995-01-01

An apparatus for sensing a target characteristic, such as relative distance between the apparatus and target, target thickness, target material, or lateral position between the apparatus and the target, includes a coil for directing an electro-magnetic field at the target. A voltage controlled oscillator energizes the coil at a resonant frequency which is functionally related to the target characteristic. The coil has an effective impedance value at resonance functionally related to the target characteristic. A frequency monitor measures the resonant frequency. An impedance monitor determines the impedance value when the drive frequency is at the resonant value. A PROM or controller determines the target characteristic in response to the measured resonant frequency and the determined impedance value. The PROM or controller provides a signal responsive to the determined target characteristic.

Assessment of recovery and recrystallisation behaviours of cold rolled IF steel through non-destructive electromagnetic characterisation

NASA Astrophysics Data System (ADS)

Roy, Rajat K.; Dutta, Siuli; Panda, Ashis K.; Rajinikanth, V.; Das, Swapan K.; Mitra, Amitava; Strangwood, M.; Davis, Claire L.

2018-07-01

The recovery and recrystallisation behaviours of cold rolled IF steel have been investigated by destructive (optical microscopy and hardness) and non-destructive electromagnetic sensor, (which allows direct measurement of strip samples with no surface preparation) techniques. The onset and completion of recrystallisation are clearly monitored through destructive techniques of optical microscopy and hardness measurements. The nucleation of new recrystallised grains is observed in the sample annealed at 600 °C/15 min, while completion of recrystallisation takes place at 700 °C/15 min. The destructive techniques are not very accurate in monitoring recovery, for example, changes in hardness of <20% are seen. In contrast, the magnetic properties of annealed steel show the onsets of both recovery and recrystallisation, with recovery accounting for ≈60% change in the coercivity value. Therefore, the measurement of magnetic softening through an electromagnetic sensor acts a crucial role for understanding recovery and recrystallisation behaviours of steels during industrial processing. The present investigation is aimed not only for controlling product quality but also saving characterisation time through off line monitoring during steel processing at industry.

Influence of a source line position on results of EM observations applied to the diagnostics of underground heating system pipelines in urban area

NASA Astrophysics Data System (ADS)

Vetrov, A.

2009-05-01

The condition of underground constructions, communication and supply systems in the cities has to be periodically monitored and controlled in order to prevent their breakage, which can result in serious accident, especially in urban area. The most risk of damage have the underground construction made of steal such as pipelines widely used for water, gas and heat supply. To ensure the pipeline survivability it is necessary to carry out the operative and inexpensive control of pipelines condition. Induced electromagnetic methods of geophysics can be applied to provide such diagnostics. The highly developed surface in urbane area is one of cause hampering the realization of electromagnetic methods of diagnostics. The main problem is in finding of an appropriate place for the source line and electrodes on a limited surface area and their optimal position relative to the observation path to minimize their influence on observed data. Author made a number of experiments of an underground heating system pipeline diagnostics using different position of the source line and electrodes. The experiments were made on a 200 meters section over 2 meters deep pipeline. The admissible length of the source line and angle between the source line and the observation path were determined. The minimal length of the source line for the experiment conditions and accuracy made 30 meters, the maximum admissible angle departure from the perpendicular position made 30 degrees. The work was undertaken in cooperation with diagnostics company DIsSO, Saint-Petersburg, Russia.

Development of a monitoring network for lightning stokes accompanying the eruptions of the Northern group of volcanoes on Kamchatka peninsula

NASA Astrophysics Data System (ADS)

Mochalov, V. A.; Firstov, P. P.; Cherneva, N. V.; Sannikov, D. V.; Akbashev, R. R.; Uvarov, V. N.; Shevtsov, B. M.; Druzhin, G. I.; Mochalova, A. V.

2017-11-01

In the region of the Northern group of volcanoes in Kamchatka peninsula, a distributed network is being planned to monitor the VLF range electromagnetic radiation and to locate the lightning strokes. It will allow the researchers to register weaker electromagnetic pulses from lightning strokes in comparison to the World Wide Lightning Location Network. The hardware-software complex of the network under construction is presented. The capabilities of the available and the developing hardware and software to investigate natural phenomena associated with lightning activity are described.

Wireless monitoring of the biological object state at microwave frequencies: A review

NASA Astrophysics Data System (ADS)

Vendik, I. B.; Vendik, O. G.; Kozlov, D. S.; Munina, I. V.; Pleskachev, V. V.; Rusakov, A. S.; Tural'chuk, P. A.

2016-01-01

Radio-frequency identification systems used for the remote diagnostics of diseases and contactless monitoring and assessment of human health are reviewed. The propagation of electromagnetic waves inside a biological medium and along interfaces between different media, as well as the problem of telemetry data acquisition from implanted systems or system on the human body surface using wireless sensors, is considered. Emphasis is on radio-frequency identification systems that use far-field electromagnetic radiation, since they are necessary in emergency situations to find injured people in hard-to-reach places and assess the state of emergency response workers.

Impact of electromagnetic radiation emitted by monitors on changes in the cellular membrane structure and protective antioxidant effect of vitamin A - In vitro study.

PubMed

Lewicka, Małgorzata; Henrykowska, Gabriela; Zawadzka, Magdalena; Rutkowski, Maciej; Pacholski, Krzysztof; Buczyński, Andrzej

2017-07-14

The increasing number of devices emitting electromagnetic radiation (EMR) in people's everyday life attracted the attention of researchers because of possible adverse effects of this factor on living organisms. One of the EMR effect may be peroxidation of lipid membranes formed as a result of free radical process. The article presents the results of in vitro studies aimed at identifying changes in malondialdehyde (MDA) concentration - a marker of lipid peroxidation and antioxidant role of vitamin A during the exposure of blood platelets to electromagnetic radiation generated by liquid-crystal-display (LCD) monitors. Electromagnetic radiation emitted by LCD monitors is characterized by parameters: 1 kHz frequency and 220 V/m intensity (15 cm from display screen). The time of exposure was 30 and 60 min. The study was conducted on porcine blood platelets. The samples were divided into 6 groups: unexposed to radiation, unexposed + vitamin A, exposed for 30 min, exposed for 30 min + vitamin A, exposed for 60 min, exposed for 60 min + vitamin A. The MDA concentration in blood platelets increases significantly as compared to control values after 60 min of exposure to EMR. A significant decrease in MDA concentration after the addition of vitamin A was noticed. In the blood samples exposed to EMR for 30 and 60 min the MDA concentration was significantly increased by addition of vitamin A. The results show the possibly negative effect of electromagnetic radiation on the cellular membrane structure manifested by changes in malondialdehyde concentration and indicate a possible protective role of vitamin A in this process. Int J Occup Med Environ Health 2017;30(5):695-703. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Electromagnetic emission memory phenomena related to LiF ionic crystal deformation

NASA Astrophysics Data System (ADS)

Mavromatou, C.; Tombras, G. S.; Ninos, D.; Hadjicontis, V.

2008-04-01

During the uniaxial compression of LiF ionic monocrystals, acoustic and electromagnetic emissions (EME) are detected. We observed that when the compression is performed in successive loading, unloading cycles and these emissions are being monitored, no new emissions will occur unless the maximum stress of the previous cycle is exceeded, meaning that the material presents memory characteristics. This is observed not only for the acoustic emission (AE), which is the well known Kaiser effect, but for the EME as well. In other words, the material appears to memorize and reveal the previously maximum stress it suffered while being deformed. The importance of an electromagnetic memory feature of a material can be related to various applications in material science, especially when the detection of AE is not feasible or gives false alert. Such cases may very well be earthquakes' predictive indications, monitoring of mines' stability, imminent landslides, etc.

Aliasing errors in measurements of beam position and ellipticity

NASA Astrophysics Data System (ADS)

Ekdahl, Carl

2005-09-01

Beam position monitors (BPMs) are used in accelerators and ion experiments to measure currents, position, and azimuthal asymmetry. These usually consist of discrete arrays of electromagnetic field detectors, with detectors located at several equally spaced azimuthal positions at the beam tube wall. The discrete nature of these arrays introduces systematic errors into the data, independent of uncertainties resulting from signal noise, lack of recording dynamic range, etc. Computer simulations were used to understand and quantify these aliasing errors. If required, aliasing errors can be significantly reduced by employing more than the usual four detectors in the BPMs. These simulations show that the error in measurements of the centroid position of a large beam is indistinguishable from the error in the position of a filament. The simulations also show that aliasing errors in the measurement of beam ellipticity are very large unless the beam is accurately centered. The simulations were used to quantify the aliasing errors in beam parameter measurements during early experiments on the DARHT-II accelerator, demonstrating that they affected the measurements only slightly, if at all.

Computer assisted positioning of the proximal segment after sagittal split osteotomy of the mandible: Preclinical investigation of a novel electromagnetic navigation system.

PubMed

Nova, Igor; Kallus, Sebastian; Berger, Moritz; Ristow, Oliver; Eisenmann, Urs; Freudlsperger, Christian; Hoffmann, Jürgen; Dickhaus, Hartmut

2017-05-01

Modifications of the temporomandibular joint position after mandible osteotomy are reluctantly accepted in orthognathic surgery. To tackle this problem, we developed a new navigation system using miniaturized electromagnetic sensors. Our imageless navigation approach is therefore optimized to avoid complications of previously proposed optical approaches such as the interference with established surgical procedures and the line of sight problem. High oblique sagittal split osteotomies were performed on 6 plastic skull mandibles in a laboratory under conditions comparable to the operating theatre. The subsequent condyle reposition was guided by an intuitive user interface and performed by electromagnetic navigation. To prove the suitability and accuracy of this novel approach for condyle navigation, the positions of 3 titanium marker screws placed on each of the proximal segments were compared using pre- and postoperative Cone Beam Computed Tomography (CBCT) imaging. Guided by the electromagnetic navigation system, positioning of the condyles was highly accurate in all dimensions. Translational discrepancies up to 0,65 mm and rotations up to 0,38° in mean could be measured postoperatively. There were no statistically significant differences between navigation results and CBCT measurements. The intuitive user interface provides a simple way to precisely restore the initial position and orientation of the proximal mandibular segments. Our electromagnetic navigation system therefore yields a promising approach for orthognathic surgery applications. Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

The detection of brain ischaemia in rats by inductive phase shift spectroscopy.

PubMed

González, C A; Villanueva, C; Vera, C; Flores, O; Reyes, R D; Rubinsky, B

2009-08-01

Ischaemia in the brain is an important clinical problem that is often monitored and studied with expensive devices such as MRI and PET, which are not readily available in low economical resource parts of the world. We have developed a new less expensive tool for non-invasive monitoring of ischaemia in the brain. This is a first feasibility study describing the concept. The system is based on the hypothesis that electromagnetic properties of the tissue change during ischaemia and that measuring the electromagnetic properties of the bulk of the brain with non-contact means can detect these changes. The apparatus we have built and whose design we describe here consists of two electromagnetic coils placed around the head. The system measures the bulk change in time of the phase difference between the electromagnetic signal on the two coils in a range of frequencies. A mathematical model simulating the device and the measurement is also introduced. Ischaemia was induced in the brain of rats by occlusion of the right cerebral and carotid arteries. Experimental subjects were monitored for 24 h. Inductive phase shift measurements were made at five frequencies in the range of 0.1-50 MHz eight times during the observation period. An ex vivo estimation of the percentage of necrosis in the ischemic subjects at t = 24 h was done. The mathematical model was also applied to the experimental tested situation. The results of both experiments and theory show significant phase shifts increase as a function of frequency and ischaemia time. The theoretical and experimental results suggest that the tested technique has the potential to detect the processes and level of ischaemia in the brain by non-invasive, continuous, bulk volumetric monitoring with a simple and inexpensive apparatus.

Continuous TDEM for monitoring shale hydraulic fracturing

NASA Astrophysics Data System (ADS)

Yan, Liang-Jun; Chen, Xiao-Xiong; Tang, Hao; Xie, Xing-Bing; Zhou, Lei; Hu, Wen-Bao; Wang, Zhong-Xin

2018-03-01

Monitoring and delineating the spatial distribution of shale fracturing is fundamentally important to shale gas production. Standard monitoring methods, such as time-lapse seismic, cross-well seismic and micro-seismic methods, are expensive, timeconsuming, and do not show the changes in the formation with time. The resistivities of hydraulic fracturing fluid and reservoir rocks were measured. The results suggest that the injection fluid and consequently the injected reservoir are characterized by very low resistivity and high chargeability. This allows using of the controlled-source electromagnetic method (CSEM) to monitor shale gas hydraulic fracturing. Based on the geoelectrical model which was proposed according to the well-log and seismic data in the test area the change rule of the reacted electrical field was studied to account for the change of shale resistivity, and then the normalized residual resistivity method for time lapse processing was given. The time-domain electromagnetic method (TDEM) was used to continuously monitor the shale gas fracturing at the Fulin shale gas field in southern China. A high-power transmitter and multi-channel transient electromagnetic receiver array were adopted. 9 h time series of Ex component of 224 sites which were laid out on the surface and over three fracturing stages of a horizontal well at 2800 m depth was recorded. After data processing and calculation of the normalized resistivity residuals, the changes in the Ex signal were determined and a dynamic 3D image of the change in resistivity was constructed. This allows modeling the spatial distribution of the fracturing fluid. The model results suggest that TDEM is promising for monitoring hydraulic fracturing of shale.

Use of electromagnetic induction methods to monitor remediation at the University of Connecticut landfill: 2004–2011

USGS Publications Warehouse

Johnson, Carole D.; White, Eric A.; Joesten, Peter K.

2012-01-01

Time‐lapse geophysical surveys using frequency‐domain electromagnetics (FDEM) can indirectly measure time‐varying hydrologic parameters such as fluid saturation or solute concentration. Monitoring of these processes provides insight into aquifer properties and the effectiveness of constructed controls (such as leachate interceptor trenches), as well as aquifer responses to natural or induced stresses. At the University of Connecticut landfill, noninvasive, electromagnetic induction (EMI) methods were used to monitor changes in subsurface electrical conductivity that were related to the landfill‐closure activities. After the landfill was closed, EMI methods were used to monitor changes in water saturation and water quality. As part of a long‐term monitoring plan to observe changes associated with closure, redevelopment, and remediation of the former landfill, EMI data were collected to supplement information from groundwater samples collected in wells to the south and north of the landfill. In comparison to single‐point measurements that could have been collected by conventional installation of additional monitoring wells, the EMI methods provided increased spatial coverage, and were less invasive and therefore less destructive to the wetland north of the landfill. To monitor effects of closure activities on the subsurface conductivity, EMI measurements were collected from 2004 to 2011 along discrete transects north and south of the landfill prior to, during, and after the landfill closure. In general, the results indicated an overall decline in subsurface electrical conductivity with time and with distance from the former landfill. This decline in electrical conductivity indicated that the closure and remediation efforts reduced the amount of leachate that originated from the landfill and that entered the drainages to the north and south of the landfill.

Monitoring of breathing motion in image-guided PBS proton therapy: comparative analysis of optical and electromagnetic technologies.

PubMed

Fattori, Giovanni; Safai, Sairos; Carmona, Pablo Fernández; Peroni, Marta; Perrin, Rosalind; Weber, Damien Charles; Lomax, Antony John

2017-03-31

Motion monitoring is essential when treating non-static tumours with pencil beam scanned protons. 4D medical imaging typically relies on the detected body surface displacement, considered as a surrogate of the patient's anatomical changes, a concept similarly applied by most motion mitigation techniques. In this study, we investigate benefits and pitfalls of optical and electromagnetic tracking, key technologies for non-invasive surface motion monitoring, in the specific environment of image-guided, gantry-based proton therapy. Polaris SPECTRA optical tracking system and the Aurora V3 electromagnetic tracking system from Northern Digital Inc. (NDI, Waterloo, CA) have been compared both technically, by measuring tracking errors and system latencies under laboratory conditions, and clinically, by assessing their practicalities and sensitivities when used with imaging devices and PBS treatment gantries. Additionally, we investigated the impact of using different surrogate signals, from different systems, on the reconstructed 4D CT images. Even though in controlled laboratory conditions both technologies allow for the localization of static fiducials with sub-millimetre jitter and low latency (31.6 ± 1 msec worst case), significant dynamic and environmental distortions limit the potential of the electromagnetic approach in a clinical setting. The measurement error in case of close proximity to a CT scanner is up to 10.5 mm and precludes its use for the monitoring of respiratory motion during 4DCT acquisitions. Similarly, the motion of the treatment gantry distorts up to 22 mm the tracking result. Despite the line of sight requirement, the optical solution offers the best potential, being the most robust against environmental factors and providing the highest spatial accuracy. The significant difference in the temporal location of the reconstructed phase points is used to speculate on the need to apply the same monitoring system for imaging and treatment to ensure the consistency of detected phases.

Development of a beam line for radio-isotope production at the KOMAC

NASA Astrophysics Data System (ADS)

Kim, Han-Sung

2016-09-01

A new beam line of the 100-MeV proton linac at the KOMAC (Korea Multi-purpose Accelerator Complex), aiming for RI (radioisotope) production has been constructed reflecting the increasing demands for various RIs (radioisotopes), such as Sr-82 and Cu-67 for medical applications. Proton beam with beam energy of 100 MeV and an average current of 0.6 mA is directed to the 100-mm-diameter production target through a beam window made of aluminum-beryllium alloy. Major components of the newly-installed beam line include electromagnets for bending and focusing, beam diagnostic systems such as a BPM (beam position monitor) and a BCM (beam current monitor), and a vacuum pumping system based on an ion pump. In this paper, the design features and the installation of the RI-production beam line at the KOMAC are given.

Calculation of electromagnetic force in electromagnetic forming process of metal sheet

NASA Astrophysics Data System (ADS)

Xu, Da; Liu, Xuesong; Fang, Kun; Fang, Hongyuan

2010-06-01

Electromagnetic forming (EMF) is a forming process that relies on the inductive electromagnetic force to deform metallic workpiece at high speed. Calculation of the electromagnetic force is essential to understand the EMF process. However, accurate calculation requires complex numerical solution, in which the coupling between the electromagnetic process and the deformation of workpiece needs be considered. In this paper, an appropriate formula has been developed to calculate the electromagnetic force in metal work-piece in the sheet EMF process. The effects of the geometric size of coil, the material properties, and the parameters of discharge circuit on electromagnetic force are taken into consideration. Through the formula, the electromagnetic force at different time and in different positions of the workpiece can be predicted. The calculated electromagnetic force and magnetic field are in good agreement with the numerical and experimental results. The accurate prediction of the electromagnetic force provides an insight into the physical process of the EMF and a powerful tool to design optimum EMF systems.

Design of piezoelectric transducer layer with electromagnetic shielding and high connection reliability

NASA Astrophysics Data System (ADS)

Qiu, Lei; Yuan, Shenfang; Shi, Xiaoling; Huang, Tianxiang

2012-07-01

Piezoelectric transducer (PZT) and Lamb wave based structural health monitoring (SHM) method have been widely studied for on-line SHM of high-performance structures. To monitor large-scale structures, a dense PZTs array is required. In order to improve the placement efficiency and reduce the wire burden of the PZTs array, the concept of the piezoelectric transducers layer (PSL) was proposed. The PSL consists of PZTs, a flexible interlayer with printed wires and signal input/output interface. For on-line SHM on real aircraft structures, there are two main issues on electromagnetic interference and connection reliability of the PSL. To address the issues, an electromagnetic shielding design method of the PSL to reduce spatial electromagnetic noise and crosstalk is proposed and a combined welding-cementation process based connection reliability design method is proposed to enhance the connection reliability between the PZTs and the flexible interlayer. Two experiments on electromagnetic interference suppression are performed to validate the shielding design of the PSL. The experimental results show that the amplitudes of the spatial electromagnetic noise and crosstalk output from the shielded PSL developed by this paper are - 15 dB and - 25 dB lower than those of the ordinary PSL, respectively. Other two experiments on temperature durability ( - 55 °C-80 °C ) and strength durability (160-1600μɛ, one million load cycles) are applied to the PSL to validate the connection reliability. The low repeatability errors (less than 3% and less than 5%, respectively) indicate that the developed PSL is of high connection reliability and long fatigue life.

Intraventricular catheter placement by electromagnetic navigation safely applied in a paediatric major head injury patient.

PubMed

Aufdenblatten, Christoph Alexander; Altermatt, Stefan

2008-09-01

In the management of severe head injuries, the use of intraventricular catheters for intracranial pressure (ICP) monitoring and the option of cerebrospinal fluid drainage is gold standard. In children and adolescents, the insertion of a cannula in a compressed ventricle in case of elevated intracranial pressure is difficult; therefore, a pressure sensor is placed more often intraparenchymal as an alternative option. In cases of persistent elevated ICP despite maximal brain pressure management, the use of an intraventricular monitoring device with the possibility of cerebrospinal fluid drainage is favourable. We present the method of intracranial catheter placement by means of an electromagnetic navigation technique.

Research on EME of real-time monitoring system

NASA Astrophysics Data System (ADS)

Meng, Ke; Guo, Jiang; Chai, Wei; Wu, Hongyan

2018-01-01

With the increase of the number of substations, the precision of electromagnetic environment parameters is higher. At present, there are many defects in the electromagnetic environment measuring system, such as the nonstandard data and the difficult reutilization. And many circuits with self-scale are controlled by switch, it has a great impact on the switching time and the service life of the device. A method of magnetic field range smooth switching is provided in this paper which is based on the magneto resistivity and the control of MCU, applying this method to the monitoring system which has functions of distributed data, real time data display, data storage and unified management etc.

Hall-effect arc protector

DOEpatents

Rankin, R.A.; Kotter, D.K.

1997-05-13

The Hall-Effect Arc Protector is used to protect sensitive electronics from high energy arcs. The apparatus detects arcs by monitoring an electrical conductor, of the instrument, for changes in the electromagnetic field surrounding the conductor which would be indicative of a possible arcing condition. When the magnitude of the monitored electromagnetic field exceeds a predetermined threshold, the potential for an instrument damaging are exists and the control system logic activates a high speed circuit breaker. The activation of the breaker shunts the energy imparted to the input signal through a dummy load to the ground. After the arc condition is terminated, the normal signal path is restored. 2 figs.

Hall-effect arc protector

DOEpatents

Rankin, Richard A.; Kotter, Dale K.

1997-01-01

The Hall-Effect Arc Protector is used to protect sensitive electronics from high energy arcs. The apparatus detects arcs by monitoring an electrical conductor, of the instrument, for changes in the electromagnetic field surrounding the conductor which would be indicative of a possible arcing condition. When the magnitude of the monitored electromagnetic field exceeds a predetermined threshold, the potential for an instrument damaging are exists and the control system logic activates a high speed circuit breaker. The activation of the breaker shunts the energy imparted to the input signal through a dummy load to the ground. After the arc condition is terminated, the normal signal path is restored.

Feasibility Study of the Electromagnetic Damper for Cable Structures Using Real-Time Hybrid Simulation

PubMed Central

Jung, Ho-Yeon; Kim, In-Ho; Jung, Hyung-Jo

2017-01-01

Cable structure is a major component of long-span bridges, such as cable-stayed and suspension bridges, and it transfers the main loads of bridges to the pylons. As these cable structures are exposed to continuous external loads, such as vehicle and wind loads, vibration control and continuous monitoring of the cable are required. In this study, an electromagnetic (EM) damper was designed and fabricated for vibration control and monitoring of the cable structure. EM dampers, also called regenerative dampers, consist of permanent magnets and coils. The electromagnetic force due to the relative motion between the coil and the permanent magnet can be used to control the vibration of the structure. The electrical energy can be used as a power source for the monitoring system. The effects of the design parameters of the damper were numerically analyzed and the damper was fabricated. The characteristics of the damper were analyzed with various external load changes. Finally, the vibration-control and energy-harvesting performances of the cable structure were evaluated through a hybrid simulation. The vibration-control and energy-harvesting performances for various loads were analyzed and the applicability to the cable structure of the EM damper was evaluated. PMID:29088077

Feasibility Study of the Electromagnetic Damper for Cable Structures Using Real-Time Hybrid Simulation.

PubMed

Jung, Ho-Yeon; Kim, In-Ho; Jung, Hyung-Jo

2017-10-31

Cable structure is a major component of long-span bridges, such as cable-stayed and suspension bridges, and it transfers the main loads of bridges to the pylons. As these cable structures are exposed to continuous external loads, such as vehicle and wind loads, vibration control and continuous monitoring of the cable are required. In this study, an electromagnetic (EM) damper was designed and fabricated for vibration control and monitoring of the cable structure. EM dampers, also called regenerative dampers, consist of permanent magnets and coils. The electromagnetic force due to the relative motion between the coil and the permanent magnet can be used to control the vibration of the structure. The electrical energy can be used as a power source for the monitoring system. The effects of the design parameters of the damper were numerically analyzed and the damper was fabricated. The characteristics of the damper were analyzed with various external load changes. Finally, the vibration-control and energy-harvesting performances of the cable structure were evaluated through a hybrid simulation. The vibration-control and energy-harvesting performances for various loads were analyzed and the applicability to the cable structure of the EM damper was evaluated.

Real-time wideband cylindrical holographic surveillance system

DOEpatents

Sheen, David M.; McMakin, Douglas L.; Hall, Thomas E.; Severtsen, Ronald H.

1999-01-01

A wideband holographic cylindrical surveillance system including a transceiver for generating a plurality of electromagnetic waves; antenna for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; the transceiver also receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; a computer for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and a display for displaying the processed information to determine nature of the target. The computer has instructions to apply Fast Fourier Transforms and obtain a three dimensional cylindrical image.

Electromagnetic miniactuators using thin magnetic layers

NASA Astrophysics Data System (ADS)

Kube, H.; Zoeppig, V.; Hermann, R.; Hoffmann, A.; Kallenbach, E.

2000-06-01

This paper presents two examples of miniactuators based on the electromagnetic and electrodynamic force generation principle respectively. They use modern high-energy polymer-bonded permanent magnetic layers basing on NdFeB. The first example is a linear drive with an integrated magnetic bearing. It generates electrodynamic forces to lift and move a lightweight platen. The position of the platen is measured and controlled. The second example is a miniature pneumatic valve with a fully integrated polarized electromagnetic actuator. The valve consumes power only when the armature position is changed. The holding force is generated without consumption of power.

Real-time holographic surveillance system

DOEpatents

Collins, H. Dale; McMakin, Douglas L.; Hall, Thomas E.; Gribble, R. Parks

1995-01-01

A holographic surveillance system including means for generating electromagnetic waves; means for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; means for receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; means for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and means for displaying the processed information to determine nature of the target. The means for processing the electrical signals includes means for converting analog signals to digital signals followed by a computer means to apply a backward wave algorithm.

Real-time wideband holographic surveillance system

DOEpatents

Sheen, David M.; Collins, H. Dale; Hall, Thomas E.; McMakin, Douglas L.; Gribble, R. Parks; Severtsen, Ronald H.; Prince, James M.; Reid, Larry D.

1996-01-01

A wideband holographic surveillance system including a transceiver for generating a plurality of electromagnetic waves; antenna for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; the transceiver also receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; a computer for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and a display for displaying the processed information to determine nature of the target. The computer has instructions to apply a three dimensional backward wave algorithm.

Real-time wideband holographic surveillance system

DOEpatents

Sheen, D.M.; Collins, H.D.; Hall, T.E.; McMakin, D.L.; Gribble, R.P.; Severtsen, R.H.; Prince, J.M.; Reid, L.D.

1996-09-17

A wideband holographic surveillance system including a transceiver for generating a plurality of electromagnetic waves; antenna for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; the transceiver also receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; a computer for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and a display for displaying the processed information to determine nature of the target. The computer has instructions to apply a three dimensional backward wave algorithm. 28 figs.

Conversion of electromagnetic energy in Z-pinch process of single planar wire arrays at 1.5 MA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liangping, Wang; Mo, Li; Juanjuan, Han

The electromagnetic energy conversion in the Z-pinch process of single planar wire arrays was studied on Qiangguang generator (1.5 MA, 100 ns). Electrical diagnostics were established to monitor the voltage of the cathode-anode gap and the load current for calculating the electromagnetic energy. Lumped-element circuit model of wire arrays was employed to analyze the electromagnetic energy conversion. Inductance as well as resistance of a wire array during the Z-pinch process was also investigated. Experimental data indicate that the electromagnetic energy is mainly converted to magnetic energy and kinetic energy and ohmic heating energy can be neglected before the final stagnation. Themore » kinetic energy can be responsible for the x-ray radiation before the peak power. After the stagnation, the electromagnetic energy coupled by the load continues increasing and the resistance of the load achieves its maximum of 0.6–1.0 Ω in about 10–20 ns.« less

Radio Frequency Identification (RFID) Based Corrosion Monitoring Sensors. Part 2: Application and Testing of the Coating Materials

DTIC Science & Technology

2014-12-22

Radio frequency identification ( RFID ) based corrosion monitoring sensors: Part II Application and testing of the coating materials Youliang He1...email: yohe@nrcan.gc.ca Keywords: Corrosion monitoring; Wireless sensor; RFID ; Electromagnetic interference; Coating. Abstract Cost-effective...Radio Frequency Identification ( RFID ) transponders (tags) were investigated for wireless corrosion monitoring by applying a metal-filled conductive

Coupled structural/thermal/electromagnetic analysis/tailoring of graded composite structures

NASA Technical Reports Server (NTRS)

Mcknight, R. L.; Huang, H.; Hartle, M.

1992-01-01

Accomplishments are described for the third years effort of a 5-year program to develop a methodology for coupled structural/thermal/electromagnetic analysis/tailoring of graded composite structures. These accomplishments include: (1) structural analysis capability specialized for graded composite structures including large deformation and deformation position eigenanalysis technologies; (2) a thermal analyzer specialized for graded composite structures; (3) absorption of electromagnetic waves by graded composite structures; and (4) coupled structural thermal/electromagnetic analysis of graded composite structures.

Bio-soliton model that predicts non-thermal electromagnetic frequency bands, that either stabilize or destabilize living cells.

PubMed

Geesink, J H; Meijer, D K F

2017-01-01

Solitons, as self-reinforcing solitary waves, interact with complex biological phenomena such as cellular self-organization. A soliton model is able to describe a spectrum of electromagnetism modalities that can be applied to understand the physical principles of biological effects in living cells, as caused by endogenous and exogenous electromagnetic fields and is compatible with quantum coherence. A bio-soliton model is proposed, that enables to predict which eigen-frequencies of non-thermal electromagnetic waves are life-sustaining and which are, in contrast, detrimental for living cells. The particular effects are exerted by a range of electromagnetic wave eigen-frequencies of one-tenth of a Hertz till Peta Hertz that show a pattern of 12 bands, and can be positioned on an acoustic reference frequency scale. The model was substantiated by a meta-analysis of 240 published articles of biological electromagnetic experiments, in which a spectrum of non-thermal electromagnetic waves were exposed to living cells and intact organisms. These data support the concept of coherent quantized electromagnetic states in living organisms and the theories of Fröhlich, Davydov and Pang. It is envisioned that a rational control of shape by soliton-waves and related to a morphogenetic field and parametric resonance provides positional information and cues to regulate organism-wide systems properties like anatomy, control of reproduction and repair.

Noninvasive Electromagnetic Detection of Bladder Cancer

PubMed Central

Cormio, Luigi; Vedruccio, Clarbruno; Leucci, Giorgio; Massenio, Paolo; Di Fino, Giuseppe; Cavaliere, Vincenzo; Carrieri, Giuseppe

2014-01-01

Objectives. Normal and neoplastic human tissues have different electromagnetic properties. This study aimed to determine the diagnostic accuracy of noninvasive electromagnetic detection of bladder cancer (BC) by the tissue-resonance interaction method (TRIM-prob). Patients and Methods. Consecutive patients were referred for cystoscopy because of (i) microscopic or gross hematuria and/or irritative voiding symptoms and (ii) bladder ultrasounds and urinary cytology findings negative or just suspicious of malignancy. Patients were first submitted to TRIM-prob bladder scanning by a single investigator and then to cystoscopy by another investigator blind to TRIM-prob data. Results. In 125 evaluated patients cystoscopy was positive for BC in 47 and negative in the remaining 78; conversely, TRIM-prob bladder scanning was positive for BC in 53 and negative in 72. In particular, TRIM-prob scanning yielded 7 false positives and only one false negative; therefore, its overall sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 97.9%, 89.9%, 86.8%, 98.6%, and 93.6%, respectively. Conclusions. TRIM-prob bladder scanning was a simple and quite accurate method for non-invasive electromagnetic detection of BC. If the elevated positive and negative predictive values will be replicated in further well-designed studies, it could be used to screen asymptomatic patients at high risk of BC. PMID:24563795

Electromagnetic fields from mobile phone base station - variability analysis.

PubMed

Bienkowski, Pawel; Zubrzak, Bartlomiej

2015-09-01

The article describes the character of electromagnetic field (EMF) in mobile phone base station (BS) surroundings and its variability in time with an emphasis on the measurement difficulties related to its pulse and multi-frequency nature. Work also presents long-term monitoring measurements performed recently in different locations in Poland - small city with dispersed building development and in major polish city - dense urban area. Authors tried to determine the trends in changing of EMF spectrum analyzing daily changes of measured EMF levels in those locations. Research was performed using selective electromagnetic meters and also EMF meter with spectrum analysis.

Intravital Computer Morphometry on Protozoa: A Method for Monitoring of the Morphofunctional Disorders in Cells Exposed in the Cell Phone Communication Electromagnetic Field.

PubMed

Uskalova, D V; Igolkina, Yu V; Sarapultseva, E I

2016-08-01

Morphofunctional disorders in unicellular aquatic protozoa - Spirostomum ambiguum infusorians after 30-, 60-, and 360-min exposure in electromagnetic field at a radiation frequency of 1 GHz and energy flow density of 50 μW/cm(2) were analyzed by intravital computer morphometry. Significant disorders in morphometric values correlated with low mobility of the protozoa. The results suggested the use of intravital computer morphometry on the protozoa for early diagnosis of radiation-induced effects of the mobile communication electromagnetic field, for example, low mobility of spermatozoa.

An all-fiber partial discharge monitoring system based on both intrinsic fiber optic interferometry sensor and fluorescent fiber

NASA Astrophysics Data System (ADS)

Yin, Zelin; Zhang, Ruirui; Tong, Jie; Chen, Xi

2013-12-01

Partial discharges (PDs) are an electrical phenomenon that occurs within a transformer whenever the voltage stress is sufficient to produce ionization in voids or inclusions within a solid dielectric, at conductor/dielectric interfaces, or in bubbles within liquid dielectrics such as oil; high-frequency transient current discharges will then appear repeatedly and will progressively deteriorate the insulation, ultimately leading to breakdown. Fiber sensor has great potential on the partial discharge detection in high-voltage equipment for its immunity to electromagnetic interference and it can take direct measurement in the high voltage equipment. The energy released in PDs produces a number of effects, resulting in flash, chemical and structural changes and electromagnetic emissions and so on. Acoustic PD detection is based on the mechanical pressure wave emitted from the discharge and fluorescent fiber PD detection is based on the emitted light produced by ionization, excitation and recombination processes during the discharge. Both of the two methods have the shortage of weak anti-interference capacity in the physical environment, like thunder or other sound source. In order to avoid the false report, an all-fiber combined PD detection system of the two methods is developed in this paper. In the system the fluorescent fiber PD sensor is considered as a reference signal, three F-P based PD detection sensors are used to both monitor the PD intensity and calculate the exact position of the discharge source. Considering the wave band of the F-P cavity and the fluorescent probe are quite different, the reflection spectrum of the F-P cavity is in the infrared region, however the fluorescent probe is about 600nm to 700nm, thus the F-P sensor and fluorescent fiber probe can be connected in one fiber and the reflection light can be detected by two different detectors without mutual interference. The all-fiber partial discharge monitoring system not only can detect the PDs but also can ensure the position of the PD source and is of great anti-interference capacity in harsh environment.

Development of Geometry Normalized Electromagnetic System (GNES) instrument for metal defect detection

NASA Astrophysics Data System (ADS)

Zakaria, Zakaria; Surbakti, Muhammad Syukri; Syahreza, Saumi; Mat Jafri, Mohd. Zubir; Tan, Kok Chooi

2017-10-01

It has been already made, calibrated and tested a geometry normalized electromagnetic system (GNES) for metal defect examination. The GNES has an automatic data acquisition system which supporting the efficiency and accuracy of the measurement. The data will be displayed on the computer monitor as a graphic display then saved automatically in the Microsoft Excel format. The transmitter will transmit the frequency pair (FP) signals i.e. 112.5 Hz and 337.5 Hz; 112.5 Hz and 1012.5 Hz; 112.5 Hz and 3037.5 Hz; 337.5 Hz and 1012.5 Hz; 337.5 Hz and 3037.5 Hz. Simultaneous transmissions of two electromagnetic waves without distortions by the transmitter will induce an eddy current in the metal. This current, in turn, will produce secondary electromagnetic fields which are measured by the receiver together with the primary fields. Measurement of percent change of a vertical component of the fields will give the percent response caused by the metal or the defect. The response examinations were performed by the models with various type of defect for the master curves. The materials of samples as a plate were using Aluminum, Brass, and Copper. The more of the defects is the more reduction of the eddy current response. The defect contrasts were tended to decrease when the more depth of the defect position. The magnitude and phase of the eddy currents will affect the loading on the coil thus its impedance. The defect must interrupt the surface eddy current flow to be detected. Defect lying parallel to the current path will not cause any significant interruption and may not be detected. The main factors which affect the eddy current response are metal conductivity, permeability, frequency, and geometry.

Real-time tracking of liver motion and deformation using a flexible needle

PubMed Central

Lei, Peng; Moeslein, Fred; Wood, Bradford J.

2012-01-01

Purpose A real-time 3D image guidance system is needed to facilitate treatment of liver masses using radiofrequency ablation, for example. This study investigates the feasibility and accuracy of using an electromagnetically tracked flexible needle inserted into the liver to track liver motion and deformation. Methods This proof-of-principle study was conducted both ex vivo and in vivo with a CT scanner taking the place of an electromagnetic tracking system as the spatial tracker. Deformations of excised livers were artificially created by altering the shape of the stage on which the excised livers rested. Free breathing or controlled ventilation created deformations of live swine livers. The positions of the needle and test targets were determined through CT scans. The shape of the needle was reconstructed using data simulating multiple embedded electromagnetic sensors. Displacement of liver tissues in the vicinity of the needle was derived from the change in the reconstructed shape of the needle. Results The needle shape was successfully reconstructed with tracking information of two on-needle points. Within 30 mm of the needle, the registration error of implanted test targets was 2.4 ± 1.0 mm ex vivo and 2.8 ± 1.5 mm in vivo. Conclusion A practical approach was developed to measure the motion and deformation of the liver in real time within a region of interest. The approach relies on redesigning the often-used seeker needle to include embedded electromagnetic tracking sensors. With the nonrigid motion and deformation information of the tracked needle, a single- or multimodality 3D image of the intraprocedural liver, now clinically obtained with some delay, can be updated continuously to monitor intraprocedural changes in hepatic anatomy. This capability may be useful in radiofrequency ablation and other percutaneous ablative procedures. PMID:20700662

Computational Electromagnetics Application to Small Geometric Anomalies and Associated Ucertainty Evaluation

DTIC Science & Technology

2010-02-28

implemented a fast method to enable the statistical characterization of electromagnetic interference and compatibility (EMI/EMC) phenomena on electrically...higher accuracy is needed, e.g., to compute higher moment statistics . To address this problem, we have developed adaptive stochastic collocation methods ...SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) AF OFFICE OF SCIENTIFIC RESEARCH 875 N. RANDOLPH ST. ROOM 3112 ARLINGTON VA 22203 UA

Picosecond beam monitor

DOEpatents

Schutt, D.W.; Beck, G.O.

1974-01-01

The current in the beam of a particle accelerator is monitored with picosecond resolution by causing the beam to impinge upon the center conductor of a coaxial line, generating a pulse of electromagnetic energy in response thereto. This pulse is detected by means such as a sampling oscilloscope. (Official Gazette)

[Dynamics of biomacromolecules in coherent electromagnetic radiation field].

PubMed

Leshcheniuk, N S; Apanasevich, E E; Tereshenkov, V I

2014-01-01

It is shown that induced oscillations and periodic displacements of the equilibrium positions occur in biomacromolecules in the absence of electromagnetic radiation absorption, due to modulation of interaction potential between atoms and groups of atoms forming the non-valence bonds in macromolecules by the external electromagnetic field. Such "hyperoscillation" state causes inevitably the changes in biochemical properties of macromolecules and conformational transformation times.

Design, construction, test and field support of a containerless payload package for rocket flight. [electromagnetic heating and confinement

NASA Technical Reports Server (NTRS)

1977-01-01

The performance of a device for electromagnetically heating and positioning containerless melts during space processing was evaluated during a 360 second 0-g suborbital sounding rocket flight. Components of the electromagnetic containerless processing package (ECPP), its operation, and interface with the rocket are described along with flight and qualification tests results.

Automatic box loader

DOEpatents

Eldridge, Harry H.; Jones, Robert A.; Lindner, Gordon M.; Hight, Paul H.

1976-01-01

This invention relates to a system for repetitively forming an assembly consisting of a single layer of tubes and a row of ferromagnetic armatures underlying the same, electromagnetically conveying the resulting assembly to a position overlying a storage box, and depositing the assembly in the box. The system includes means for simultaneously depositing a row of the armatures on the inclined surface of a tube retainer. Tubes then are rolled down the surface to form a single tube layer bridging the armatures. A magnet assembly carrying electromagnets respectively aligned with the armatures is advanced close to the tube layer, and in the course of this advance is angularly displaced to bring the pole pieces of the electromagnets into parallelism with the tube layer. The magnets then are energized to pick up the assembly. The loaded magnet assembly is retracted to a position overlying the box, and during this retraction is again displaced to bring the pole pieces of the electromagnets into a horizontal plane. Means are provided for inserting the loaded electromagnets in the box and then de-energizing the electromagnets to deposit the assembly therein. The system accomplishes the boxing of fragile tubes at relatively high rates. Because the tubes are boxed as separated uniform layers, subsequent unloading operations are facilitated.

Nasoenteral feeding tube placement by nurses using an electromagnetic guidance system (with video).

PubMed

Mathus-Vliegen, Elisabeth M H; Duflou, Ann; Spanier, Marcel B W; Fockens, Paul

2010-04-01

The early institution of feeding in patients who need postpyloric feeding tubes is often hampered by a limited availability of endoscopists experienced in safe tube positioning. To test the feasibility of having nurses place postpyloric feeding tubes by using a universal path finding system device. Prospective study. Academic hospital. The success rate and learning curve of a senior nurse placing postpyloric feeding tubes in 50 patients was studied, followed by a study in 160 patients on the success rates and learning curves of 4 inexperienced nurses instructed by the senior nurse. Finally, the success rate of postpyloric feeding tube placement by the senior nurse in 50 critically ill patients was investigated. Postpyloric feeding tube positioning by nurses using an electromagnetic universal path-finding system device enabling them to follow the path of the tip of the feeding tube on a monitor screen. Success was defined by postpyloric positioning of the feeding tube. The ultimate aim was to reach at least the duodenojejunal flexure. In the first part, the senior nurse was successful in 72% of cases. There was a clear learning curve. In the second part, the 4 newly instructed nurses had a success rate of 89.4% without an evident learning curve. In the third part, successful feeding tube positioning was achieved in 78% of critically ill patients. Of the 217 successfully positioned tubes, 74% reached at least the duodenojejunal flexure. In half of the unsuccessful cases, an explanation for the failure was found at endoscopy. No complications were seen. The generalization to less-specialized hospitals should be investigated. Postpyloric positioning of feeding tubes by nurses at the bedside without endoscopy is feasible and safe. Nurses may take over some of the tasks of doctors in a time of high endoscopic needs. Copyright 2010 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

Fiber-optically sensorized composite wing

NASA Astrophysics Data System (ADS)

Costa, Joannes M.; Black, Richard J.; Moslehi, Behzad; Oblea, Levy; Patel, Rona; Sotoudeh, Vahid; Abouzeida, Essam; Quinones, Vladimir; Gowayed, Yasser; Soobramaney, Paul; Flowers, George

2014-04-01

Electromagnetic interference (EMI) immune and light-weight, fiber-optic sensor based Structural Health Monitoring (SHM) will find increasing application in aerospace structures ranging from aircraft wings to jet engine vanes. Intelligent Fiber Optic Systems Corporation (IFOS) has been developing multi-functional fiber Bragg grating (FBG) sensor systems including parallel processing FBG interrogators combined with advanced signal processing for SHM, structural state sensing and load monitoring applications. This paper reports work with Auburn University on embedding and testing FBG sensor arrays in a quarter scale model of a T38 composite wing. The wing was designed and manufactured using fabric reinforced polymer matrix composites. FBG sensors were embedded under the top layer of the composite. Their positions were chosen based on strain maps determined by finite element analysis. Static and dynamic testing confirmed expected response from the FBGs. The demonstrated technology has the potential to be further developed into an autonomous onboard system to perform load monitoring, SHM and Non-Destructive Evaluation (NDE) of composite aerospace structures (wings and rotorcraft blades). This platform technology could also be applied to flight testing of morphing and aero-elastic control surfaces.

Stability of stationary-axisymmetric black holes in vacuum general relativity to axisymmetric electromagnetic perturbations

NASA Astrophysics Data System (ADS)

Prabhu, Kartik; Wald, Robert M.

2018-01-01

We consider arbitrary stationary and axisymmetric black holes in general relativity in (d +1) dimensions (with d ≥slant 3 ) that satisfy the vacuum Einstein equation and have a non-degenerate horizon. We prove that the canonical energy of axisymmetric electromagnetic perturbations is positive definite. This establishes that all vacuum black holes are stable to axisymmetric electromagnetic perturbations. Our results also hold for asymptotically de Sitter black holes that satisfy the vacuum Einstein equation with a positive cosmological constant. Our results also apply to extremal black holes provided that the initial perturbation vanishes in a neighborhood of the horizon.

Real-time wideband cylindrical holographic surveillance system

DOEpatents

Sheen, D.M.; McMakin, D.L.; Hall, T.E.; Severtsen, R.H.

1999-01-12

A wideband holographic cylindrical surveillance system is disclosed including a transceiver for generating a plurality of electromagnetic waves; antenna for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; the transceiver also receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; a computer for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and a display for displaying the processed information to determine nature of the target. The computer has instructions to apply Fast Fourier Transforms and obtain a three dimensional cylindrical image. 13 figs.

Real-time holographic surveillance system

DOEpatents

Collins, H.D.; McMakin, D.L.; Hall, T.E.; Gribble, R.P.

1995-10-03

A holographic surveillance system is disclosed including means for generating electromagnetic waves; means for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; means for receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; means for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and means for displaying the processed information to determine nature of the target. The means for processing the electrical signals includes means for converting analog signals to digital signals followed by a computer means to apply a backward wave algorithm. 21 figs.

Electromagnetic free suspension system for space manufacturing. Volume 1: Technology department

NASA Technical Reports Server (NTRS)

Buerger, E. H.; Frost, R. T.; Lambert, R. H.; Oconnor, M. F.; Odell, E. L. G.; Napaluch, L. J.; Stockhoff, E. H.; Wouch, G.

1972-01-01

The technology developed in defining a facility to be used on the Skylab mission for electromagnetic suspension of small, molten spheres in the weightless space environment is described. The technologies discussed include: four-coil optimization, four-coil versus six-coil configuration comparison, four-coil position servocontrol, four-coil breadboard, position sensing and servosystem, two-color pyrometer, and specimen toration mode analysis.

Verifying placement of small-bore feeding tubes: electromagnetic device images versus abdominal radiographs.

PubMed

Bryant, Vera; Phang, Jean; Abrams, Kevin

2015-11-01

Clinicians are unsure if radiography is needed to confirm correct positioning of feeding tubes inserted with assistance from an electromagnetic system. To compare radiographic reports of feeding tube placement with images generated by an electromagnetic feeding tube placement device. The medical records of 200 consecutive patients who had feeding tubes inserted with assistance from an electromagnetic feeding tube placement device were reviewed retrospectively. Radiographic reports of tube site were compared with images generated by the device. Radiographic evidence of tube sites was available in 188 cases: 184 tubes were located in portions of the gastrointestinal tract. Ninety of the 188 tubes were situated in the optimal site (distal duodenum or jejunum) radiographically. Images generated by the electromagnetic device were available in 176 cases; of these, 52 tubes appeared to end in the expected left lower quadrant. Tubes shown on radiographs to be in other sites also occasionally appeared to end in the left lower quadrant. Nurses using the device did not recognize 4 of the 188 tubes (2.1%) that were inadvertently placed in the lung. No consistent pattern of quadrant distribution was found for tubes positioned in the stomach or proximal duodenum. Images generated by the electromagnetic tube placement device provided inconsistent results regarding tube location. A small percentage of seriously malpositioned tubes were not detected by using the electromagnetic device. These findings do not support eliminating radiographs to confirm correct tube placement following use of an electromagnetic tube placement device. ©2015 American Association of Critical-Care Nurses.

Measurement of electromagnetic waves in ELF and VLF bands to monitor lightning activity in the Maritime Continent

NASA Astrophysics Data System (ADS)

Yamashita, Kozo; Takahashi, Yukihiro; Ohya, Hiroyo; Tsuchiya, Fuminori; Sato, Mitsuteru; Matsumoto, Jun

2013-04-01

Data of lightning discharge has been focused on as an effective way for monitoring and nowcasting of thunderstorm activity which causes extreme weather. Spatial distribution of lightning discharge has been used as a proxy of the presence or absence of deep convection. Latest observation shows that there is extremely huge lightning whose scale is more than hundreds times bigger than that of averaged event. This result indicates that lightning observation should be carried out to estimate not only existence but also scale for quantitative evaluation of atmospheric convection. In this study, lightning observation network in the Maritime Continent is introduced. This network is consisted of the sensors which make possible to measure electromagnetic wave radiated from lightning discharges. Observation frequency is 0.1 - 40 kHz for the measurement of magnetic field and 1 - 40 kHz for that of electric field. Sampling frequency is 100 kHz. Waveform of electromagnetic wave is recorded by personal computer. We have already constructed observation stations at Tainan in Taiwan (23.1N, 121.1E), Saraburi in Thailand (14.5N, 101.0E), and Pontianak in Indonesia (0.0N, 109.4E). Furthermore, we plan to install the monitoring system at Los Banos in Philippines (14.18, 121.25E) and Hanoi in Viet Nam. Data obtained by multipoint observation is synchronized by GPS receiver installed at each station. By using data obtained by this network, location and scale of lightning discharge can be estimated. Location of lightning is determined based on time of arrival method. Accuracy of geolocation could be less than 10km. Furthermore, charge moment is evaluated as a scale of each lightning discharge. It is calculated from electromagnetic waveform in ELF range (3-30 kHz). At the presentation, we will show the initial result about geolocation for source of electromagnetic wave and derivation of charge moment value based on the measurement of ELF and VLF sferics.

Study on the electromagnetic radiation characteristics of discharging excimer laser system

NASA Astrophysics Data System (ADS)

Zhao, Duliang; Liang, Xu; Fang, Xiaodong; Wang, Qingsheng

2016-10-01

Excimer laser in condition of high voltage, large current and fast discharge will produce strong electromagnetic pulse radiation and electromagnetic interference on the around electrical equipment. The research on characteristics and distribution of excimer laser electromagnetic radiation could provide important basis for electromagnetic shielding and suppressing electromagnetic interference, and further improving the electromagnetic compatibility of system. Firstly, electromagnetic radiation source is analyzed according to the working principle of excimer laser. The key test points of the electromagnetic radiation, hydrogen thyratron, main discharge circuit and laser outlet, are determined by the mechanical structure and the theory of electromagnetic radiation. Secondly, characteristics of electromagnetic field were tested using a near field probe on the key positions of the vertical direction at 20, 50, and 80 cm, respectively. The main radiation frequencies and the radiation field characteristics in the near field are obtained. The experimental results show that the main radiation frequencies distribute in 47, 65, and 130 MHz for electric field and the main radiation frequencies distribute in 34, 100, and 165 MHz for magnetic field. The intensity of electromagnetic field decreases rapidly with the increase of test distance. The higher the frequency increases, the faster the amplitude attenuate. Finally, several electromagnetic interference suppression measurement methods are proposed from the perspective of electromagnetic compatibility according to the test results.

Monitoring dynamic reactions of red blood cells to UHF electromagnetic waves radiation using a novel micro-imaging technology.

PubMed

Ruan, Ping; Yong, Junguang; Shen, Hongtao; Zheng, Xianrong

2012-12-01

Multiple state-of-the-art techniques, such as multi-dimensional micro-imaging, fast multi-channel micro-spetrophotometry, and dynamic micro-imaging analysis, were used to dynamically investigate various effects of cell under the 900 MHz electromagnetic radiation. Cell changes in shape, size, and parameters of Hb absorption spectrum under different power density electromagnetic waves radiation were presented in this article. Experimental results indicated that the isolated human red blood cells (RBCs) do not have obviously real-time responses to the ultra-low density (15 μW/cm(2), 31 μW/cm(2)) electromagnetic wave radiation when the radiation time is not more than 30 min; however, the cells do have significant reactions in shape, size, and the like, to the electromagnetic waves radiation with power densities of 1 mW/cm(2) and 5 mW/cm(2). The data also reveal the possible influences and statistical relationships among living human cell functions, radiation amount, and exposure time with high-frequency electromagnetic waves. The results of this study may be significant on protection of human being and other living organisms against possible radiation affections of the high-frequency electromagnetic waves.

Electromagnetic containerless processing requirements and recommended facility concept and capabilities for space lab

NASA Technical Reports Server (NTRS)

Frost, R. T.; Bloom, H. L.; Napaluch, L. J.; Stockhoff, E. H.; Wouch, G.

1974-01-01

Containerless melting, reaction, and solidification experiments and processes which potentially can lead to new understanding of material science and production of new or improved materials in the weightless space environment are reviewed in terms of planning for spacelab. Most of the experiments and processes discussed are amenable to the employment of electromagnetic position control and electromagnetic induction or electron beam heating and melting. The spectrum of relevant properties of materials, which determine requirements for a space laboratory electromagnetic containerless processing facility are reviewed. Appropriate distributions and associated coil structures are analyzed and compared on the basis of efficiency, for providing the functions of position sensing, control, and induction heating. Several coil systems are found capable of providing these functions. Exchangeable modular coils in appropriate sizes are recommended to achieve the maximum power efficiencies, for a wide range of specimen sizes and resistivities, in order to conserve total facility power.

Micro-fabricated integrated coil and magnetic circuit and method of manufacturing thereof

DOEpatents

Mihailovich, Robert E.; Papavasiliou, Alex P.; Mehrotra, Vivek; Stupar, Philip A.; Borwick, III, Robert L.; Ganguli, Rahul; DeNatale, Jeffrey F.

2017-03-28

A micro-fabricated electromagnetic device is provided for on-circuit integration. The electromagnetic device includes a core. The core has a plurality of electrically insulating layers positioned alternatingly between a plurality of magnetic layers to collectively form a continuous laminate having alternating magnetic and electrically insulating layers. The electromagnetic device includes a coil embedded in openings of the semiconductor substrate. An insulating material is positioned in the cavity and between the coil and an inner surface of the core. A method of manufacturing the electromagnetic device includes providing a semiconductor substrate having openings formed therein. Windings of a coil are electroplated and embedded in the openings. The insulating material is coated on or around an exposed surface of the coil. Alternating magnetic layers and electrically insulating layers may be micro-fabricated and electroplated as a single and substantially continuous segment on or around the insulating material.

Analyses of electromagnetic and piezoelectric systems for efficient vibration energy harvesting

NASA Astrophysics Data System (ADS)

Hadas, Z.; Smilek, J.; Rubes, O.

2017-05-01

The paper deals with analyses and evaluation of vibration energy harvesting systems which are based on electromagnetic and piezoelectric physical principles off electro-mechanical conversion. Energy harvesting systems are associated with wireless sensors and a monitoring of engineering objects. The most of engineering objects operate with unwanted mechanical vibrations. However, vibrations could provide an ambient source of energy which is converted into useful electricity. The use of electromagnetic and piezoelectric vibration energy harvesters is analyzed in this paper. Thee evaluated output power is used for a choice of the efficient system with respect to the character of vibrations and thee required power output.

Proceedings of the Workshop on an Electromagnetic Positioning System in Space

NASA Technical Reports Server (NTRS)

Oran, W. A. (Editor)

1978-01-01

A workshop was convened to help determine if sufficient justification existed to proceed with the design of an electromagnetic (EM) positioning device for use in space. Those in attendance included experts in crystal growth, nucleation phenomena, containerless processing techniques, properties of materials, metallurgical techniques, and glass technology. Specific areas mentioned included the study of metallic glasses and investigations of the properties of high temperature materials.

Non-contact and contact measurement system for detecting projectile position in electromagnetic launch bore

NASA Astrophysics Data System (ADS)

Xu, Weidong; Yuan, Weiqun; Xu, Rong; Zhao, Hui; Cheng, Wenping; Zhang, Dongdong; Zhao, Ying; Yan, Ping

2017-12-01

This paper introduces a new measurement system for measuring the position of a projectile within a rapid fire electromagnetic launching system. The measurement system contains both non-contact laser shading and metal fiber contact measurement devices. Two projectiles are placed in the rapid fire electromagnetic launch bore, one in the main accelerating segment and the other in the pre-loading segment. The projectile placed in the main accelerating segment should be shot first, and then the other is loaded into the main segment from the pre-loading segment. The main driving current (I-main) can only be discharged again when the second projectile has arrived at the key position (the projectile position corresponds to the discharging time) in the main accelerating segment. So, it is important to be able to detect when the second projectile arrives at the key position in the main accelerating segment. The B-dot probe is the most widely used system for detecting the position of the projectile in the electromagnetic launch bore. However, the B-dot signal is affected by the driving current amplitude and the projectile velocity. There is no current in the main accelerating segment when the second projectile moves into this segment in rapid fire mode, so the B-dot signal for detecting the key position is invalid. Due to the presence of a high-intensity magnetic field, a high current, a high-temperature aluminum attachment, smoke and strong vibrations, it is very difficult to detect the projectile position in the bore accurately. So, other measurements need to be researched and developed in order to achieve high reliability. A measurement system based on a laser (non-contact) and metal fibers (contact) has been designed, and the integrated output signal based on this detector is described in the following paper.

Linear magnetic bearings

NASA Technical Reports Server (NTRS)

Goldowskiy, M. P.

1984-01-01

A self regulating, nonfrictional, active magnetic bearing is disclosed which has an elongated cylindrical housing for containing a shaft type armature with quadrature positioned shaft position sensors and equidistantly positioned electromagnets located at one end of the housing. Each set of sensors is responsive to orthogonal displacement of the armature and is used to generate control signals to energize the electromagnets to center the armature. A bumper magnet assembly is located at one end of the housing for dampening any undesired axial movement of the armature or to axially move the armature either continuously or fixedly.

Positive and negative ion beam merging system for neutral beam production

DOEpatents

Leung, Ka-Ngo; Reijonen, Jani

2005-12-13

The positive and negative ion beam merging system extracts positive and negative ions of the same species and of the same energy from two separate ion sources. The positive and negative ions from both sources pass through a bending magnetic field region between the pole faces of an electromagnet. Since the positive and negative ions come from mirror image positions on opposite sides of a beam axis, and the positive and negative ions are identical, the trajectories will be symmetrical and the positive and negative ion beams will merge into a single neutral beam as they leave the pole face of the electromagnet. The ion sources are preferably multicusp plasma ion sources. The ion sources may include a multi-aperture extraction system for increasing ion current from the sources.

Active System for Electromagnetic Perturbation Monitoring in Vehicles

NASA Astrophysics Data System (ADS)

Matoi, Adrian Marian; Helerea, Elena

Nowadays electromagnetic environment is rapidly expanding in frequency domain and wireless services extend in terms of covered area. European electromagnetic compatibility regulations refer to limit values regarding emissions, as well as procedures for determining susceptibility of the vehicle. Approval procedure for a series of cars is based on determining emissions/immunity level for a few vehicles picked randomly from the entire series, supposing that entire vehicle series is compliant. During immunity assessment, the vehicle is not subjected to real perturbation sources, but exposed to electric/magnetic fields generated by laboratory equipment. Since current approach takes into account only partially real situation regarding perturbation sources, this paper proposes an active system for determining electromagnetic parameters of vehicle's environment, that implements a logical diagram for measurement, satisfying the imposed requirements. This new and original solution is useful for EMC assessment of hybrid and electrical vehicles.

Development of software for geodynamic processes monitoring system

NASA Astrophysics Data System (ADS)

Kabanov, M. M.; Kapustin, S. N.; Gordeev, V. F.; Botygin, I. A.; Tartakovsky, V. A.

2017-11-01

This article justifies the usage of natural pulsed electromagnetic Earth's noises logging method for mapping anomalies of strain-stress state of Earth's crust. The methods and technologies for gathering, processing and systematization of data gathered by ground multi-channel geophysical loggers for monitoring geomagnetic situation have been experimentally tested, and software had been developed. The data was consolidated in a network storage and can be accessed without using any specialized client software. The article proposes ways to distinguish global and regional small-scale time-space variations of Earth's natural electromagnetic field. For research purposes, the software provides a way to export data for any given period of time for any loggers and displays measurement data charts for selected set of stations.

ELECTROMAGNETIC APPARATUS FOR MOVING A ROD

DOEpatents

Young, J.N.

1957-08-20

An electromagnetic device for moving an object in a linear path by increments is described. The device is specifically adapted for moving a neutron absorbing control rod into and out of the core of a reactor and consists essentially of an extension member made of magnetic material connected to one end of the control rod and mechanically flexible to grip the walls of a sleeve member when flexed, a magnetic sleeve member coaxial with and slidable between limit stops along the flexible extension, electromagnetic coils substantially centrally located with respect to the flexible extension to flex the extension member into gripping engagement with the sleeve member when ener gized, moving electromagnets at each end of the sleeve to attract the sleeve when energized, and a second gripping electromagnet positioned along the flexible extension at a distance from the previously mentioned electromagnets for gripping the extension member when energized. In use, the second gripping electromagnet is deenergized, the first gripping electromagnet is energized to fix the extension member in the sleeve, and one of the moving electromagnets is energized to attract the sleeve member toward it, thereby moving the control rod.

A compact ball screw based electromagnetic energy harvester for railroad application

NASA Astrophysics Data System (ADS)

Pan, Yu; Lin, Teng; Liu, Cheng; Yu, Jie; Zuo, Jianyong; Zuo, Lei

2018-03-01

To enable the smart technologies, such as the positive train controls, rail damage detection and track health monitoring on the railroad side, the electricity is required and in needed. In this paper, we proposed a novel ball-screw based electromagnetic energy harvester for railway track with mechanical-motion-rectifier (MMR) mechanism, to harvest the energy that usually dissipated and wasted during train induced track vibration. Ball screw based design reduces backlash during motion transmission, and MMR nonlinear characteristics with one way clutches makes the harvester convert the bi-direction track vibration into a generator's unidirectional rotation, which improves the transmission reliability and increases the energy harvesting efficiency. A systematic model combining train-rail-harvester was established to analyze the dynamic characteristic of the proposed railway energy, and lab and in-field tests were carried out to experimentally characterize the proposed energy harvester. In lab bench test showed the proposed harvester reached a 70% mechanical efficiency with a high sensitivity to the environment vibration. In filed test showed that a peak 7.8W phase power was achieved when a two marshaling type A metro train passed by with a 30 km/h.

Long bunch trains measured using a prototype cavity beam position monitor for the Compact Linear Collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cullinan, F. J.; Boogert, S. T.; Farabolini, W.

2015-11-19

The Compact Linear Collider (CLIC) requires beam position monitors (BPMs) with 50 nm spatial resolution for alignment of the beam line elements in the main linac and beam delivery system. Furthermore, the BPMs must be able to make multiple independent measurements within a single 156 ns long bunch train. A prototype cavity BPM for CLIC has been manufactured and tested on the probe beam line at the 3rd CLIC Test Facility (CTF3) at CERN. The transverse beam position is determined from the electromagnetic resonant modes excited by the beam in the two cavities of the pickup, the position cavity and the referencemore » cavity. The mode that is measured in each cavity resonates at 15 GHz and has a loaded quality factor that is below 200. Analytical expressions for the amplitude, phase and total energy of signals from long trains of bunches have been derived and the main conclusions are discussed. The results of the beam tests are presented. The variable gain of the receiver electronics has been characterized using beam excited signals and the form of the signals for different beam pulse lengths with the 2/3 ns bunch spacing has been observed. The sensitivity of the reference cavity signal to charge and the horizontal position signal to beam offset have been measured and are compared with theoretical predictions based on laboratory measurements of the BPM pickup and the form of the resonant cavity modes as determined by numerical simulation. Lastly, the BPM was calibrated so that the beam position jitter at the BPM location could be measured. It is expected that the beam jitter scales linearly with the beam size and so the results are compared to predicted values for the latter.« less

Long bunch trains measured using a prototype cavity beam position monitor for the Compact Linear Collider

NASA Astrophysics Data System (ADS)

Cullinan, F. J.; Boogert, S. T.; Farabolini, W.; Lefevre, T.; Lunin, A.; Lyapin, A.; Søby, L.; Towler, J.; Wendt, M.

2015-11-01

The Compact Linear Collider (CLIC) requires beam position monitors (BPMs) with 50 nm spatial resolution for alignment of the beam line elements in the main linac and beam delivery system. Furthermore, the BPMs must be able to make multiple independent measurements within a single 156 ns long bunch train. A prototype cavity BPM for CLIC has been manufactured and tested on the probe beam line at the 3rd CLIC Test Facility (CTF3) at CERN. The transverse beam position is determined from the electromagnetic resonant modes excited by the beam in the two cavities of the pickup, the position cavity and the reference cavity. The mode that is measured in each cavity resonates at 15 GHz and has a loaded quality factor that is below 200. Analytical expressions for the amplitude, phase and total energy of signals from long trains of bunches have been derived and the main conclusions are discussed. The results of the beam tests are presented. The variable gain of the receiver electronics has been characterized using beam excited signals and the form of the signals for different beam pulse lengths with the 2 /3 ns bunch spacing has been observed. The sensitivity of the reference cavity signal to charge and the horizontal position signal to beam offset have been measured and are compared with theoretical predictions based on laboratory measurements of the BPM pickup and the form of the resonant cavity modes as determined by numerical simulation. Finally, the BPM was calibrated so that the beam position jitter at the BPM location could be measured. It is expected that the beam jitter scales linearly with the beam size and so the results are compared to predicted values for the latter.

Computational Electromagnetic Modeling of SansEC(Trade Mark) Sensors

NASA Technical Reports Server (NTRS)

Smith, Laura J.; Dudley, Kenneth L.; Szatkowski, George N.

2011-01-01

This paper describes the preliminary effort to apply computational design tools to aid in the development of an electromagnetic SansEC resonant sensor composite materials damage detection system. The computational methods and models employed on this research problem will evolve in complexity over time and will lead to the development of new computational methods and experimental sensor systems that demonstrate the capability to detect, diagnose, and monitor the damage of composite materials and structures on aerospace vehicles.

An Attachable Electromagnetic Energy Harvester Driven Wireless Sensing System Demonstrating Milling-Processes and Cutter-Wear/Breakage-Condition Monitoring.

PubMed

Chung, Tien-Kan; Yeh, Po-Chen; Lee, Hao; Lin, Cheng-Mao; Tseng, Chia-Yung; Lo, Wen-Tuan; Wang, Chieh-Min; Wang, Wen-Chin; Tu, Chi-Jen; Tasi, Pei-Yuan; Chang, Jui-Wen

2016-02-23

An attachable electromagnetic-energy-harvester driven wireless vibration-sensing system for monitoring milling-processes and cutter-wear/breakage-conditions is demonstrated. The system includes an electromagnetic energy harvester, three single-axis Micro Electro-Mechanical Systems (MEMS) accelerometers, a wireless chip module, and corresponding circuits. The harvester consisting of magnets with a coil uses electromagnetic induction to harness mechanical energy produced by the rotating spindle in milling processes and consequently convert the harnessed energy to electrical output. The electrical output is rectified by the rectification circuit to power the accelerometers and wireless chip module. The harvester, circuits, accelerometer, and wireless chip are integrated as an energy-harvester driven wireless vibration-sensing system. Therefore, this completes a self-powered wireless vibration sensing system. For system testing, a numerical-controlled machining tool with various milling processes is used. According to the test results, the system is fully self-powered and able to successfully sense vibration in the milling processes. Furthermore, by analyzing the vibration signals (i.e., through analyzing the electrical outputs of the accelerometers), criteria are successfully established for the system for real-time accurate simulations of the milling-processes and cutter-conditions (such as cutter-wear conditions and cutter-breaking occurrence). Due to these results, our approach can be applied to most milling and other machining machines in factories to realize more smart machining technologies.

An Attachable Electromagnetic Energy Harvester Driven Wireless Sensing System Demonstrating Milling-Processes and Cutter-Wear/Breakage-Condition Monitoring

PubMed Central

Chung, Tien-Kan; Yeh, Po-Chen; Lee, Hao; Lin, Cheng-Mao; Tseng, Chia-Yung; Lo, Wen-Tuan; Wang, Chieh-Min; Wang, Wen-Chin; Tu, Chi-Jen; Tasi, Pei-Yuan; Chang, Jui-Wen

2016-01-01

An attachable electromagnetic-energy-harvester driven wireless vibration-sensing system for monitoring milling-processes and cutter-wear/breakage-conditions is demonstrated. The system includes an electromagnetic energy harvester, three single-axis Micro Electro-Mechanical Systems (MEMS) accelerometers, a wireless chip module, and corresponding circuits. The harvester consisting of magnets with a coil uses electromagnetic induction to harness mechanical energy produced by the rotating spindle in milling processes and consequently convert the harnessed energy to electrical output. The electrical output is rectified by the rectification circuit to power the accelerometers and wireless chip module. The harvester, circuits, accelerometer, and wireless chip are integrated as an energy-harvester driven wireless vibration-sensing system. Therefore, this completes a self-powered wireless vibration sensing system. For system testing, a numerical-controlled machining tool with various milling processes is used. According to the test results, the system is fully self-powered and able to successfully sense vibration in the milling processes. Furthermore, by analyzing the vibration signals (i.e., through analyzing the electrical outputs of the accelerometers), criteria are successfully established for the system for real-time accurate simulations of the milling-processes and cutter-conditions (such as cutter-wear conditions and cutter-breaking occurrence). Due to these results, our approach can be applied to most milling and other machining machines in factories to realize more smart machining technologies. PMID:26907297

An exact solution to the relativistic equation of motion of a charged particle driven by a linearly polarized electromagnetic wave

NASA Technical Reports Server (NTRS)

Shebalin, John V.

1988-01-01

An exact analytic solution is found for a basic electromagnetic wave-charged particle interaction by solving the nonlinear equations of motion. The particle position, velocity, and corresponding time are found to be explicit functions of the total phase of the wave. Particle position and velocity are thus implicit functions of time. Applications include describing the motion of a free electron driven by an intense laser beam..

Experimental research of the influence of the strength of ore samples on the parameters of an electromagnetic signal during acoustic excitation in the process of uniaxial compression

NASA Astrophysics Data System (ADS)

Yavorovich, L. V.; Bespal`ko, A. A.; Fedotov, P. I.

2018-01-01

Parameters of electromagnetic responses (EMRe) generated during uniaxial compression of rock samples under excitation by deterministic acoustic pulses are presented and discussed. Such physical modeling in the laboratory allows to reveal the main regularities of electromagnetic signals (EMS) generation in rock massive. The influence of the samples mechanical properties on the parameters of the EMRe excited by an acoustic signal in the process of uniaxial compression is considered. It has been established that sulfides and quartz in the rocks of the Tashtagol iron ore deposit (Western Siberia, Russia) contribute to the conversion of mechanical energy into the energy of the electromagnetic field, which is expressed in an increase in the EMS amplitude. The decrease in the EMS amplitude when the stress-strain state of the sample changes during the uniaxial compression is observed when the amount of conductive magnetite contained in the rock is increased. The obtained results are important for the physical substantiation of testing methods and monitoring of changes in the stress-strain state of the rock massive by the parameters of electromagnetic signals and the characteristics of electromagnetic emission.

Planar Steering of a Single Ferrofluid Drop by Optimal Minimum Power Dynamic Feedback Control of Four Electromagnets at a Distance

PubMed Central

Probst, R.; Lin, J.; Komaee, A.; Nacev, A.; Cummins, Z.

2010-01-01

Any single permanent or electro magnet will always attract a magnetic fluid. For this reason it is difficult to precisely position and manipulate ferrofluid at a distance from magnets. We develop and experimentally demonstrate optimal (minimum electrical power) 2-dimensional manipulation of a single droplet of ferrofluid by feedback control of 4 external electromagnets. The control algorithm we have developed takes into account, and is explicitly designed for, the nonlinear (fast decay in space, quadratic in magnet strength) nature of how the magnets actuate the ferrofluid, and it also corrects for electro-magnet charging time delays. With this control, we show that dynamic actuation of electro-magnets held outside a domain can be used to position a droplet of ferrofluid to any desired location and steer it along any desired path within that domain – an example of precision control of a ferrofluid by magnets acting at a distance. PMID:21218157

Apparatus and Methods for Mitigating Electromagnetic Emissions

NASA Technical Reports Server (NTRS)

Geng, Steven M. (Inventor); Niedra, Janis M. (Inventor)

2013-01-01

Apparatus, methods, and other embodiments associated with mitigation of magnetic fields are described herein. In an embodiment, a method for mitigating an electromagnetic field includes positioning a mitigating coil around a linear alternator of linear motor so that the mitigating coil is coaxially located with an alternator coil; arranging the mitigating coil to generate a field to mitigate an electromagnetic field generated by the alternator coil; and passing an induced current from the alternator coil through the mitigating coil.

Apparatus and Methods for Mitigating Electromagnetic Emissions

NASA Technical Reports Server (NTRS)

Geng, Steven M. (Inventor); Niedra, Janis M. (Inventor)

2016-01-01

Apparatus, methods, and other embodiments associated with mitigation of magnetic fields are described herein. In an embodiment, a method for mitigating an electromagnetic field includes positioning a mitigating coil around a linear alternator of linear motor so that the mitigating coil is coaxially located with an alternator coil; arranging the mitigating coil to generate a field to mitigate an electromagnetic field generated by the alternator coil; and passing an induced current from the alternator coil through the mitigating coil.

Electromagnetic-Tracked Biopsy under Ultrasound Guidance: Preliminary Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hakime, Antoine, E-mail: thakime@yahoo.com; Deschamps, Frederic; Marques De Carvalho, Enio Garcia

2012-08-15

Purpose: This study was designed to evaluate the accuracy and safety of electromagnetic needle tracking for sonographically guided percutaneous liver biopsies. Methods: We performed 23 consecutive ultrasound-guided liver biopsies for liver nodules with an electromagnetic tracking of the needle. A sensor placed at the tip of a sterile stylet (18G) inserted in a coaxial guiding trocar (16G) used for biopsy was localized in real time relative to the ultrasound imaging plane, thanks to an electromagnetic transmitter and two sensors on the ultrasound probe. This allows for electronic display of the needle tip location and the future needle path overlaid onmore » the real-time ultrasound image. Distance between needle tip position and its electronic display, number of needle punctures, number of needle pull backs for redirection, technical success (needle positioned in the target), diagnostic success (correct histopathology result), procedure time, and complication were evaluated according to lesion sizes, depth and location, operator experience, and 'in-plane' or 'out-of-plane' needle approach. Results: Electronic display was always within 2 mm from the real position of the needle tip. The technical success rate was 100%. A single needle puncture without repuncture was used in all patients. Pull backs were necessary in six patients (26%) to obtain correct needle placement. The overall diagnostic success rate was 91%. The overall true-positive, true-negative, false-negative, and failure rates of the biopsy were 100% (19/19) 100% (2/2), 0% (0/23), and 9% (2/23). The median total procedure time from the skin puncture to the needle in the target was 30 sec (from 5-60 s). Lesion depth and localizations, operator experience, in-plane or out-of-plane approach did not affect significantly the technical, diagnostic success, or procedure time. Even when the tumor size decreased, the procedure time did not increase. Conclusions: Electromagnetic-tracked biopsy is accurate to determine needle tip position and allows fast and accurate needle placement in targeted liver nodules.« less

Fracture induced electromagnetic emissions: extending laboratory findings by observations at the geophysical scale

NASA Astrophysics Data System (ADS)

Potirakis, Stelios M.; Contoyiannis, Yiannis; Kopanas, John; Kalimeris, Anastasios; Antonopoulos, George; Peratzakis, Athanasios; Eftaxias, Konstantinos; Nomicos, Constantinos

2014-05-01

Under natural conditions, it is practically impossible to install an experimental network on the geophysical scale using the same instrumentations as in laboratory experiments for understanding, through the states of stress and strain and their time variation, the laws that govern the friction during the last stages of EQ generation, or to monitor (much less to control) the principal characteristics of a fracture process. Fracture-induced electromagnetic emissions (EME) in a wide range of frequency bands are sensitive to the micro-structural chances. Thus, their study constitutes a nondestructive method for the monitoring of the evolution of damage process at the laboratory scale. It has been suggested that fracture induced MHz-kHz electromagnetic (EM) emissions, which emerge from a few days up to a few hours before the main seismic shock occurrence permit a real time monitoring of the damage process during the last stages of earthquake preparation, as it happens at the laboratory scale. Since the EME are produced both in the case of the laboratory scale fracture and the EQ preparation process (geophysical scale fracture) they should present similar characteristics in these two scales. Therefore, both the laboratory experimenting scientists and the experimental scientists studying the pre-earthquake EME could benefit from each- other's results. Importantly, it is noted that when studying the fracture process by means of laboratory experiments, the fault growth process normally occurs violently in a fraction of a second. However, a major difference between the laboratory and natural processes is the order-of-magnitude differences in scale (in space and time), allowing the possibility of experimental observation at the geophysical scale for a range of physical processes which are not observable at the laboratory scale. Therefore, the study of fracture-induced EME is expected to reveal more information, especially for the last stages of the fracture process, when it is conducted at the geophysical scale. As a characteristic example, we discuss about the case of electromagnetic silence before the global rupture that was first observed in preseismic EME and recently was also observed in the EME measured during laboratory fracture experiments, completely revising the earlier views about the fracture-induced electromagnetic emissions.

Virtual-Instrument-Based Online Monitoring System for Hands-on Laboratory Experiment of Partial Discharges

ERIC Educational Resources Information Center

Karmakar, Subrata

2017-01-01

Online monitoring of high-voltage (HV) equipment is a vital tool for early detection of insulation failure. Most insulation failures are caused by partial discharges (PDs) inside the HV equipment. Because of the very high cost of establishing HV equipment facility and the limitations of electromagnetic interference-screened laboratories, only a…

First results of geodetic deformation monitoring after commencement of CO2 injection at the Aquistore underground CO2 storage site

NASA Astrophysics Data System (ADS)

Craymer, M.; White, D.; Piraszewski, M.; Zhao, Y.; Henton, J.; Silliker, J.; Samsonov, S.

2015-12-01

Aquistore is a demonstration project for the underground storage of CO2 at a depth of ~3350 m near Estevan, Saskatchewan, Canada. An objective of the project is to design, adapt, and test non-seismic monitoring methods that have not been systematically utilized to date for monitoring CO2 storage projects, and to integrate the data from these various monitoring tools to obtain quantitative estimates of the change in subsurface fluid distributions, pressure changes and associated surface deformation. Monitoring methods being applied include satellite-, surface- and wellbore-based monitoring systems and comprise natural- and controlled-source electromagnetic methods, gravity monitoring, continuous GPS, synthetic aperture radar interferometry (InSAR), tiltmeter array analysis, and chemical tracer studies. Here we focus on the GPS, InSAR and gravity monitoring. Five monitoring sites were installed in 2012 and another six in 2013, each including GPS and InSAR corner reflector monuments (some collocated on the same monument). The continuous GPS data from these stations have been processed on a daily basis in both baseline processing mode using the Bernese GPS Software and precise point positioning mode using CSRS-PPP. Gravity measurements at each site have also been performed in fall 2013, spring 2014 and fall 2015, and at two sites in fall 2014. InSAR measurements of deformation have been obtained for a 5 m footprint at each site as well as at the corner reflector point sources. Here we present the first results of this geodetic deformation monitoring after commencement of CO2 injection on April 14, 2015. The time series of these sites are examined, compared and analyzed with respect to monument stability, seasonal signals, longer term trends, and any changes in motion and mass since CO2 injection.

Vocal and visual stimulation, congruence and lateralization affect brain oscillations in interspecies emotional positive and negative interactions.

PubMed

Balconi, Michela; Vanutelli, Maria Elide

2016-01-01

The present research explored the effect of cross-modal integration of emotional cues (auditory and visual (AV)) compared with only visual (V) emotional cues in observing interspecies interactions. The brain activity was monitored when subjects processed AV and V situations, which represented an emotional (positive or negative), interspecies (human-animal) interaction. Congruence (emotionally congruous or incongruous visual and auditory patterns) was also modulated. electroencephalography brain oscillations (from delta to beta) were analyzed and the cortical source localization (by standardized Low Resolution Brain Electromagnetic Tomography) was applied to the data. Frequency band (mainly low-frequency delta and theta) showed a significant brain activity increasing in response to negative compared to positive interactions within the right hemisphere. Moreover, differences were found based on stimulation type, with an increased effect for AV compared with V. Finally, delta band supported a lateralized right dorsolateral prefrontal cortex (DLPFC) activity in response to negative and incongruous interspecies interactions, mainly for AV. The contribution of cross-modality, congruence (incongruous patterns), and lateralization (right DLPFC) in response to interspecies emotional interactions was discussed at light of a "negative lateralized effect."

Study on electromagnetic radiation and mechanical characteristics of coal during an SHPB test

NASA Astrophysics Data System (ADS)

Chengwu, Li; Qifei, Wang; Pingyang, Lyu

2016-06-01

Dynamic loads provided by a Split Hopkinson pressure bar are applied in the impact failure experiment on coal with an impact velocity of 4.174-17.652 m s-1. The mechanical property characteristics of coal and an electromagnetic radiation signal can be detected and measured during the experiment. The variation of coal stress, strain, incident energy, dissipated energy and other mechanical parameters are analyzed by the unidimensional stress wave theory. It suggests that with an increase of the impact velocity, the mechanical parameters and electromagnetic radiation increased significantly and the dissipated energy of the coal sample has a high discrete growing trend during the failure process of coal impact. Combined with the received energy of the electromagnetic radiation signal, the relationship between these mechanical parameters and electromagnetic radiation during the failure process of coal burst could be analyzed by the grey correlation model. The results show that the descending order of the gray correlation degree between the mechanical characteristics and electromagnetic radiation energy are impact velocity, maximum stress, the average stress, incident energy, the average strain, maximum strain, the average strain rate and dissipation energy. Due to the correlation degree, the impact velocity and incident energy are relatively large, and the main factor affecting the electromagnetic radiation energy of coal is the energy magnitude. While the relationship between extreme stress and the radiation energy change trend is closed, the stress state of coal has a greater impact on electromagnetic radiation than the strain and destruction which can deepen the research of the coal-rock dynamic disaster electromagnetic monitoring technique.

Mapping saltwater intrusion in the Biscayne Aquifer, Miami-Dade County, Florida using transient electromagnetic sounding

USGS Publications Warehouse

Fitterman, David V.

2014-01-01

Saltwater intrusion in southern Florida poses a potential threat to the public drinking-water supply that is typically monitored using water samples and electromagnetic induction logs collected from a network of wells. Transient electromagnetic (TEM) soundings are a complementary addition to the monitoring program because of their ease of use, low cost, and ability to fill in data gaps between wells. TEM soundings have been used to map saltwater intrusion in the Biscayne aquifer over a large part of south Florida including eastern Miami-Dade County and the Everglades. These two areas are very different with one being urban and the other undeveloped. Each poses different conditions that affect data collection and data quality. In the developed areas, finding sites large enough to make soundings is difficult. The presence of underground pipes further restricts useable locations. Electromagnetic noise, which reduces data quality, is also an issue. In the Everglades, access to field sites is difficult and working in water-covered terrain is challenging. Nonetheless, TEM soundings are an effective tool for mapping saltwater intrusion. Direct estimates of water quality can be obtained from the inverted TEM data using a formation factor determined for the Biscayne aquifer. This formation factor is remarkably constant over Miami-Dade County owing to the uniformity of the aquifer and the absence of clay. Thirty-six TEM soundings were collected in the Model Land area of southeast Miami-Dade County to aid in calibration of a helicopter electromagnetic (HEM) survey. The soundings and HEM survey revealed an area of saltwater intrusion aligned with canals and drainage ditches along U.S. Highway 1 and the Card Sound Road. These canals and ditches likely reduced freshwater levels through unregulated drainage and provided pathways for seawater to flow at least 12.4 km inland.

Multiband rectenna for microwave applications

NASA Astrophysics Data System (ADS)

Okba, Abderrahim; Takacs, Alexandru; Aubert, Hervé; Charlot, Samuel; Calmon, Pierre-François

2017-02-01

This paper reports a multiband rectenna (rectifier + antenna) suitable for the electromagnetic energy harvesting of the spill-over loss of microwave antennas placed on board of geostationary satellites. Such rectenna is used for powering autonomous wireless sensors for satellite health monitoring. The topology of the rectenna is presented. The experimental results demonstrate that the proposed compact rectenna can harvest efficiently the incident electromagnetic energy at three different frequencies that are close to the resonant frequencies of the cross-dipoles implemented in the antenna array. xml:lang="fr"

Respiratory rate detection using a wearable electromagnetic generator.

PubMed

Padasdao, Bryson; Boric-Lubecke, Olga

2011-01-01

Wearable health and fitness monitoring systems are a promising new way of collecting physiological data without inconveniencing patients. Human energy harvesting may be used to power wearable sensors. In this paper, we explore this zero-net energy biosensor concept through sensing and harvesting of respiratory effort. An off the shelf servo motor operation in reverse was used to successfully obtain respiratory rate, while also demonstrating significant harvested power. These are the first reported respiratory rate sensing results using electromagnetic generators.

The Role of Electrical Anisotropy in Modeling and Interpreting Controlled-Source Electromagnetic Responses for Hydraulic Fracture Monitoring

NASA Astrophysics Data System (ADS)

Trevino, S., III; Hickey, M. S.; Everett, M. E.

2017-12-01

Controlled-Source Electromagnetics (CSEM) can be used to monitor the movement and extent of injection fluid during a hydraulic fracture. The response of the fluid to energization by a CSEM source is dependent upon the electrical conductivity difference between the fluid and background geological formation. An important property that must be taken into account when modeling and interpreting CSEM responses is that electrical conductivity may be anisotropic. We study the effect of electrical anisotropy in both the background formation and the fluid-injection zone. First, various properties of the background formation can affect anisotropy including variations in grain size, composition and bedding-plane orientation. In certain formations, such as shale, the horizontal component of the conductivity can be more than an order of magnitude larger than the vertical component. We study this effect by computing differences in surface CSEM responses using the analytic 1-D anisotropic primary solution of a horizontal electric dipole positioned at the surface. Second, during hydraulic fracturing, the injected fluid can create new fractures and infill existing natural fractures. To include the explicit fracture geometry in modeling, a large increase in the number of nodes and computational time is required which may not be feasible. An alternative is to instead model the large-scale fracture geometry as a uniform slab with an appropriate bulk conductivity. Micro-scale fracture geometry may cause preferential fluid propagation in a single direction or plane which can be represented by electrical anisotropy of the slab. To study such effects of bulk anisotropy on CSEM responses we present results from multiple scenarios of surface to surface hydraulic fracture monitoring using 3-D finite element modeling. The model uses Coulomb-gauged potentials to solve Maxwell's equations in the frequency domain and we have updated the code to allow a triaxial electrical conductivity tensor to be specified. By allowing for formation and target electrical anisotropy these modeling results contribute to a better understanding and faster interpretation of field data.

Asymptotic symmetries and electromagnetic memory

NASA Astrophysics Data System (ADS)

Pasterski, Sabrina

2017-09-01

Recent investigations into asymptotic symmetries of gauge theory and gravity have illuminated connections between gauge field zero-mode sectors, the corresponding soft factors, and their classically observable counterparts — so called "memories". Namely, low frequency emissions in momentum space correspond to long time integrations of the corre-sponding radiation in position space. Memory effect observables constructed in this manner are non-vanishing in typical scattering processes, which has implications for the asymptotic symmetry group. Here we complete this triad for the case of large U(1) gauge symmetries at null infinity. In particular, we show that the previously studied electromagnetic memory effect, whereby the passage of electromagnetic radiation produces a net velocity kick for test charges in a distant detector, is the position space observable corresponding to th Weinberg soft photon pole in momentum space scattering amplitudes.

Measurement of electromagnetic fields generated by air traffic control radar systems with spectrum analysers.

PubMed

Barellini, A; Bogi, L; Licitra, G; Silvi, A M; Zari, A

2009-12-01

Air traffic control (ATC) primary radars are 'classical' radars that use echoes of radiofrequency (RF) pulses from aircraft to determine their position. High-power RF pulses radiated from radar antennas may produce high electromagnetic field levels in the surrounding area. Measurement of electromagnetic fields produced by RF-pulsed radar by means of a swept-tuned spectrum analyser are investigated here. Measurements have been carried out both in the laboratory and in situ on signals generated by an ATC primary radar.

Electromagnetic Nanoparticles for Sensing and Medical Diagnostic Applications

PubMed Central

Vegni, Lucio

2018-01-01

A modeling and design approach is proposed for nanoparticle-based electromagnetic devices. First, the structure properties were analytically studied using Maxwell’s equations. The method provides us a robust link between nanoparticles electromagnetic response (amplitude and phase) and their geometrical characteristics (shape, geometry, and dimensions). Secondly, new designs based on “metamaterial” concept are proposed, demonstrating great performances in terms of wide-angle range functionality and multi/wide behavior, compared to conventional devices working at the same frequencies. The approach offers potential applications to build-up new advanced platforms for sensing and medical diagnostics. Therefore, in the final part of the article, some practical examples are reported such as cancer detection, water content measurements, chemical analysis, glucose concentration measurements and blood diseases monitoring. PMID:29652853

A linearly controlled direct-current power source for high-current inductive loads in a magnetic suspension wind tunnel

NASA Technical Reports Server (NTRS)

Tripp, John S.; Daniels, Taumi S.

1990-01-01

The NASA Langley 6 inch magnetic suspension and balance system (MSBS) requires an independently controlled bidirectional DC power source for each of six positioning electromagnets. These electromagnets provide five-degree-of-freedom control over a suspended aerodynamic test model. Existing power equipment, which employs resistance coupled thyratron controlled rectifiers as well as AC to DC motor generator converters, is obsolete, inefficient, and unreliable. A replacement six phase bidirectional controlled bridge rectifier is proposed, which employs power MOSFET switches sequenced by hybrid analog/digital circuits. Full load efficiency is 80 percent compared to 25 percent for the resistance coupled thyratron system. Current feedback provides high control linearity, adjustable current limiting, and current overload protection. A quenching circuit suppresses inductive voltage impulses. It is shown that 20 kHz interference from positioning magnet power into MSBS electromagnetic model position sensors results predominantly from capacitively coupled electric fields. Hence, proper shielding and grounding techniques are necessary. Inductively coupled magnetic interference is negligible.

A solid-state controllable power supply for a magnetic suspension wind tunnel

NASA Technical Reports Server (NTRS)

Daniels, Taumi S.; Tripp, John S.

1991-01-01

The NASA Langley 6-inch Magnetic Suspension and Balance System (6-in. MSBS) requires an independently controlled bidirectional dc power source for each of six positioning electromagnets. These electromagnets provide five-degree-of-freedom control over a suspended aerodynamic test model. Existing power equipment, which employs resistance-coupled thyratron-controlled rectifiers as well as ac to dc motor-generator converters, is obsolete, inefficient, and unreliable. A replacement six-phase bidirectional controlled bridge rectifier is proposed, which employs power MOSFET switches sequenced by hybrid analog/digital circuits. Full-load efficiency is 80 percent compared with 25 percent for the resistance-coupled thyratron system. Current feedback provides high control linearity, adjustable current limiting, and current overload protection. A quenching circuit suppresses inductive voltage impulses. It is shown that 20-kHz interference from positioning magnet power into MSBS electromagnetic model position sensors results predominantly from capacitively coupled electric fields. Hence, proper shielding and grounding techniques are necessary. Inductively coupled magnetic interference is negligible.

High-Energy Electromagnetic Offline Follow-Up of Ligo-Virgo Gravitational-Wave Binary Coalescence Candidate Events

NASA Technical Reports Server (NTRS)

Blackburn, L.; Briggs, M. S.; Camp, J.; Christensen, N.; Connaughton, V.; Jenke, P.; Remillard, R. A.; Veitch, J.

2015-01-01

We present two different search methods for electromagnetic counterparts to gravitational-wave (GW) events from ground-based detectors using archival NASA high-energy data from the Fermi Gamma-ray Burst Monitor (GBM) and RXTE All-sky Monitor (ASM) instruments. To demonstrate the methods, we use a limited number of representative GW background noise events produced by a search for binary neutron star coalescence over the last two months of the LIGO-Virgo S6/VSR3 joint science run. Time and sky location provided by the GW data trigger a targeted search in the high-energy photon data. We use two custom pipelines: one to search for prompt gamma-ray counterparts in GBM, and the other to search for a variety of X-ray afterglow model signals in ASM. We measure the efficiency of the joint pipelines to weak gamma-ray burst counterparts, and a family of model X-ray afterglows. By requiring a detectable signal in either electromagnetic instrument coincident with a GW event, we are able to reject a large majority of GW candidates. This reduces the signal-to-noise ratio of the loudest surviving GW background event by around 15-20 percent.

HIGH-ENERGY ELECTROMAGNETIC OFFLINE FOLLOW-UP OF LIGO-VIRGO GRAVITATIONAL-WAVE BINARY COALESCENCE CANDIDATE EVENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blackburn, L.; Camp, J.; Briggs, M. S.

2015-03-15

We present two different search methods for electromagnetic counterparts to gravitational-wave (GW) events from ground-based detectors using archival NASA high-energy data from the Fermi Gamma-ray Burst Monitor (GBM) and RXTE All-sky Monitor (ASM) instruments. To demonstrate the methods, we use a limited number of representative GW background noise events produced by a search for binary neutron star coalescence over the last two months of the LIGO-Virgo S6/VSR3 joint science run. Time and sky location provided by the GW data trigger a targeted search in the high-energy photon data. We use two custom pipelines: one to search for prompt gamma-ray counterpartsmore » in GBM, and the other to search for a variety of X-ray afterglow model signals in ASM. We measure the efficiency of the joint pipelines to weak gamma-ray burst counterparts, and a family of model X-ray afterglows. By requiring a detectable signal in either electromagnetic instrument coincident with a GW event, we are able to reject a large majority of GW candidates. This reduces the signal-to-noise ratio of the loudest surviving GW background event by around 15–20%.« less

Merging Infrasound and Electromagnetic Signals as a Means for Nuclear Explosion Detection

NASA Astrophysics Data System (ADS)

Ashkenazy, Joseph; Lipshtat, Azi; Kesar, Amit S.; Pistinner, Shlomo; Ben Horin, Yochai

2016-04-01

The infrasound monitoring network of the CTBT consists of 60 stations. These stations are capable of detecting atmospheric events, and may provide approximate location within time scale of a few hours. However, the nature of these events cannot be deduced from the infrasound signal. More than two decades ago it was proposed to use the electromagnetic pulse (EMP) as a means of discriminating nuclear explosion from other atmospheric events. An EMP is a unique signature of nuclear explosion and is not detected from chemical ones. Nevertheless, it was decided to exclude the EMP technology from the official CTBT verification regime, mainly because of the risk of high false alarm rate, due to lightning electromagnetic pulses [1]. Here we present a method of integrating the information retrieved from the infrasound system with the EMP signal which enables us to discriminate between lightning discharges and nuclear explosions. Furthermore, we show how spectral and other characteristics of the electromagnetic signal emitted from a nuclear explosion are distinguished from those of lightning discharge. We estimate the false alarm probability of detecting a lightning discharge from a given area of the infrasound event, and identifying it as a signature of a nuclear explosion. We show that this probability is very low and conclude that the combination of infrasound monitoring and EMP spectral analysis may produce a reliable method for identifying nuclear explosions. [1] R. Johnson, Unfinished Business: The Negotiation of the CTBT and the End of Nuclear Testing, United Nations Institute for Disarmament Research, 2009.

Wideband analysis of railway catenary line radiation and new applications of its unintentional emitted signals

NASA Astrophysics Data System (ADS)

Heddebaut, Marc; Deniau, Virginie; Rioult, Jean

2018-06-01

Generally, in railway networks, dissipated energy—and its consequences in terms of noise, ballast attrition, electromagnetic interference, etc—is considered a nuisance generated by this means of transport. Therefore, most studies are carried out with the aim of reducing it. This paper takes the opposite view and considers the particular case of the irreducible electromagnetic interference generated along an electrified line, in order to propose new applications beneficial to railway operations. At a selected representative location, wideband (ranging from 10 kHz to 1 GHz) electromagnetic field measurements are performed successively during, and not during, high speed train passages. We deduce two potential applications of these unintentional signals. At low frequency, the first proposal considers energy harvesting using the received electromagnetic interference as the source. This received energy can be converted and used to DC feed low consumption sensors to be installed along the railway infrastructure. These sensors participate in monitoring infrastructure health and in making it more resilient to internal and external stresses. At higher frequencies, for the second proposal, radiation from the catenary line and train pantograph is specifically examined at a carefully selected sub-band. The results are also studied following a time–frequency analysis, to introduce a new nondestructive inspection method of the sliding contact between the catenary line and the train pantograph. Ultimately, this technique could offer a new means of monitoring the health of both the catenary line and the pantograph.

Measurement of electromagnetic tracking error in a navigated breast surgery setup

NASA Astrophysics Data System (ADS)

Harish, Vinyas; Baksh, Aidan; Ungi, Tamas; Lasso, Andras; Baum, Zachary; Gauvin, Gabrielle; Engel, Jay; Rudan, John; Fichtinger, Gabor

2016-03-01

PURPOSE: The measurement of tracking error is crucial to ensure the safety and feasibility of electromagnetically tracked, image-guided procedures. Measurement should occur in a clinical environment because electromagnetic field distortion depends on positioning relative to the field generator and metal objects. However, we could not find an accessible and open-source system for calibration, error measurement, and visualization. We developed such a system and tested it in a navigated breast surgery setup. METHODS: A pointer tool was designed for concurrent electromagnetic and optical tracking. Software modules were developed for automatic calibration of the measurement system, real-time error visualization, and analysis. The system was taken to an operating room to test for field distortion in a navigated breast surgery setup. Positional and rotational electromagnetic tracking errors were then calculated using optical tracking as a ground truth. RESULTS: Our system is quick to set up and can be rapidly deployed. The process from calibration to visualization also only takes a few minutes. Field distortion was measured in the presence of various surgical equipment. Positional and rotational error in a clean field was approximately 0.90 mm and 0.31°. The presence of a surgical table, an electrosurgical cautery, and anesthesia machine increased the error by up to a few tenths of a millimeter and tenth of a degree. CONCLUSION: In a navigated breast surgery setup, measurement and visualization of tracking error defines a safe working area in the presence of surgical equipment. Our system is available as an extension for the open-source 3D Slicer platform.

Comparison of Precision between Optical and Electromagnetic Navigation Systems in Total Knee Arthroplasty

PubMed Central

Rhee, Seung Joon; Park, Shi Hwan; Cho, He Myung

2014-01-01

Purpose The purpose of this study is to compare and analyze the precision of optical and electromagnetic navigation systems in total knee arthroplasty (TKA). Materials and Methods We retrospectively reviewed 60 patients who underwent TKA using an optical navigation system and 60 patients who underwent TKA using an electromagnetic navigation system from June 2010 to March 2012. The mechanical axis that was measured on preoperative radiographs and by the intraoperative navigation systems were compared between the groups. The postoperative positions of the femoral and tibial components in the sagittal and coronal plane were assessed. Results The difference of the mechanical axis measured on the preoperative radiograph and by the intraoperative navigation systems was 0.6 degrees more varus in the electromagnetic navigation system group than in the optical navigation system group, but showed no statistically significant difference between the two groups (p>0.05). The positions of the femoral and tibial components in the sagittal and coronal planes on the postoperative radiographs also showed no statistically significant difference between the two groups (p>0.05). Conclusions In TKA, both optical and electromagnetic navigation systems showed high accuracy and reproducibility, and the measurements from the postoperative radiographs showed no significant difference between the two groups. PMID:25505703

A Low Frequency Electromagnetic Sensor for Indirect Measurement of Glucose Concentration: In Vitro Experiments in Different Conductive Solutions

PubMed Central

Tura, Andrea; Sbrignadello, Stefano; Cianciavicchia, Domenico; Pacini, Giovanni; Ravazzani, Paolo

2010-01-01

In recent years there has been considerable interest in the study of glucose-induced dielectric property variations of human tissues as a possible approach for non-invasive glycaemia monitoring. We have developed an electromagnetic sensor, and we tested in vitro its ability to estimate variations in glucose concentration of different solutions with similarities to blood (sodium chloride and Ringer-lactate solutions), differing though in the lack of any cellular components. The sensor was able to detect the effect of glucose variations over a wide range of concentrations (∼78–5,000 mg/dL), with a sensitivity of ∼0.22 mV/(mg/dL). Our proposed system may thus be useful in a new approach for non-invasive and non-contact glucose monitoring. PMID:22219665

Polymer and ceramic nanocomposites for aerospace applications

NASA Astrophysics Data System (ADS)

Rathod, Vivek T.; Kumar, Jayanth S.; Jain, Anjana

2017-11-01

This paper reviews the potential of polymer and ceramic matrix composites for aerospace/space vehicle applications. Special, unique and multifunctional properties arising due to the dispersion of nanoparticles in ceramic and metal matrix are briefly discussed followed by a classification of resulting aerospace applications. The paper presents polymer matrix composites comprising majority of aerospace applications in structures, coating, tribology, structural health monitoring, electromagnetic shielding and shape memory applications. The capabilities of the ceramic matrix nanocomposites to providing the electromagnetic shielding for aircrafts and better tribological properties to suit space environments are discussed. Structural health monitoring capability of ceramic matrix nanocomposite is also discussed. The properties of resulting nanocomposite material with its disadvantages like cost and processing difficulties are discussed. The paper concludes after the discussion of the possible future perspectives and challenges in implementation and further development of polymer and ceramic nanocomposite materials.

Electromagnetic interference in intraoperative monitoring of motor evoked potentials and a wireless solution.

PubMed

Farajidavar, Aydin; Seifert, Jennifer L; Delgado, Mauricio R; Sparagana, Steven; Romero-Ortega, Mario I; Chiao, J-C

2016-02-01

Intraoperative neurophysiological monitoring (IONM) is utilized to minimize neurological morbidity during spine surgery. Transcranial motor evoked potentials (TcMEPs) are principal IONM signals in which the motor cortex of the subject is stimulated with electrical pulses and the evoked potentials are recorded from the muscles of interest. Currently available monitoring systems require the connection of 40-60 lengthy lead wires to the patient. These wires contribute to a crowded and cluttered surgical environment, and limit the maneuverability of the surgical team. In this work, it was demonstrated that the cumbersome wired system is vulnerable to electromagnetic interference (EMI) produced by operating room (OR) equipment. It was hypothesized that eliminating the lengthy recording wires can remove the EMI induced in the IONM signals. Hence, a wireless system to acquire TcMEPs was developed and validated through bench-top and animal experiments. Side-by-side TcMEPs acquisition from the wired and wireless systems in animal experiments under controlled conditions (absence of EMI from OR equipment) showed comparable magnitudes and waveforms, thus demonstrating the fidelity in the signal acquisition of the wireless solution. The robustness of the wireless system to minimize EMI was compared with a wired-system under identical conditions. Unlike the wired-system, the wireless system was not influenced by the electromagnetic waves from the C-Arm X-ray machine and temperature management system in the OR. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

Ultrastructural Study on Ultra-Low Frequency Electromagnetic Fields and Transfer Factor Effects on Skin Ulcers

NASA Astrophysics Data System (ADS)

Cadena, M. S. Reyes; Chapul, L. Sánchez; Pérez, Javiér; García, M. N. Jiménez; López, M. A. Jiménez; Espíndola, M. E. Sánchez; Perez, R. Paniagua; Hernández, N. A.; Paniagua, G.; Uribe, F.; Nava, J. J. Godina; Segura, M. A. Rodríguez

2008-08-01

We determined the effect of 120Hz ultra low frequency electromagnetic field (ELF) on the healing process of skin in 20 Wistar rats distributed in four groups in which chronic dermal ulcers had been produced. The first two groups received a dose of the transfer factor and interferon-beta (IFN-β) every 24 h during 12 days. The third group (positive control) received only electromagnetic field (ELF) sessions, and in the fourth group (negative control), no treatment was applied. The electromagnetic field was applied through a Helmholtz coils; 30 Gauss of intensity. Results shown histological changes that improve the healing process in animals subjected to ELF together with the transfer factor.

The ISTIMES project: a new integrated system for monitoring critical transport infrastructures interested by natural hazards

NASA Astrophysics Data System (ADS)

Proto, Monica; Massimo, Bavusi; Francesco, Soldovieri

2010-05-01

The research project "Integrated System for Transport Infrastructure surveillance and Monitoring by Electromagnetic Sensing" (ISTIMES), was approved in the 7th Framework Programme, in the Joint Call ICT and Security and started on 1st July 2009. The purpose of ISTIMES project is to design, assess and promote an ICT-based system, exploiting distributed and local sensors, for non-destructive electromagnetic monitoring in order to achieve the critical transport infrastructures more reliable and safe. The transportation sector's components are susceptible to the consequences of natural disasters and can also be attractive as terrorist targets. The sector's size, its physically dispersed and decentralized nature, the many public and private entities involved in its operations, the critical importance of cost considerations, and the inherent requirement of convenient accessibility to its services by all users - make the transportation particularly vulnerable to security and safety threats. As well known, the surface transportation system consists of interconnected infrastructures including highways, transit systems, railroads, airports, waterways, pipelines and ports, and the vehicles, aircraft, and vessels that operate along these networks. Thus, interdependencies exist between transportation and nearly every other sector of the economy and the effective operation of this system is essential to the European economic productivity; therefore, transportation sector protection is of paramount importance since threats to it may impact other industries that rely on it. The system exploits an open network architecture that can accommodate a wide range of sensors, static and mobile, and can be easily scaled up to allow the integration of additional sensors and interfacing with other networks. It relies on heterogeneous state-of-the-art electromagnetic sensors, enabling a self-organizing, self-healing, ad-hoc networking of terrestrial sensors, supported by specific satellite measurements. The integration of electromagnetic technologies with new ICT information and telecommunications systems enables remotely controlled monitoring and surveillance and real time data imaging of the critical transport infrastructures. Thus, the proposal will concern also with the development of tools for handling, analysing and processing large data volume (Information Fusion) and then providing information and performing behaviour prediction in a quick, easy and intuitive way (Situation Awareness). The proposal is based on several independent non-invasive imaging technologies based on electromagnetic sensing. Sensor cross validation, synergy and new data fusion and correlation schemes will permit a multi-method, multi-resolution and multi-scale electromagnetic detection and monitoring of surface and subsurface changes of the infrastructure. According to GMES and European Spatial Data Infrastructure (ESDI) initiatives, the system will adopt open architectures and will make efforts to achieve full interoperability. The system will be tested on two very challenging test beds such as: a highway-bridge and a railway tunnel. The system will be based on clear end-user requirements, coming from representative end-users and technological choices will be based on a long term cost-benefit analysis. Then, a dissemination plan was included into the project to encourage a wide range of public institutions and private companies to evaluate and adopt our approach for real-time control and distributed monitoring also in the more general framework of critical and civil infrastructure management and protection. Finally, an exploitation plan will develop for the commercialization of any derived technology, software, or monitoring concepts. ISTIMES project is carried out by an international partnership formed by nine partners coming from seven countries: Tecnologie per le Osservazioni della Terra (TeRN), Elsag Datamat (ED) and Dipartimento della Protezione Civile (DPC) from Italy, Eidgenoessische Materialpruefungs-und Forschungsanstalt (EMPA) from Switzerland, Laboratoire Central des Ponts et Chaussées (LCPC) from France, Lund University (ULUND) from Sweden, Tel Aviv University (TAU) from Israel, Territorial Data Elaboration (TDE) from Romania and Norsk Elektro Optikk (NEO) from Norway.

Deep inspiration breath hold with electromagnetic confirmation of chest wall position for adjuvant therapy of left-sided breast cancer: Technique and accuracy.

PubMed

Kathpal, Madeera; Tinnel, Brent; Sun, Kelly; Ninneman, Stephanie; Malmer, Cynthia; Wendt, Stacie; Buff, Sheena; Valentich, David; Gossweiler, Marisa; Macdonald, Dusten

2016-01-01

With most patients now living long after their breast cancer diagnosis, minimizing long-term side effects of breast cancer treatment, such as reducing late cardiac and pulmonary side effects of radiation therapy (RT), is particularly important. It is now possible to use an electromagnetic tracking system to allow real-time tracking of chest wall (CW) position during the delivery of RT. Here, we report our experience using electromagnetic surface transponders as an added measure of CW position during deep inspiration breath hold (DIBH). We conducted a single-institution institutional review board-approved retrospective review of 15 female left-sided breast cancer patients treated between July 2012 and June 2013 with conventional whole breast radiation. We compared daily port films with treatment planning digitally reconstructed radiographs to establish daily setup accuracy, then used Calypso tracings to compare the position of the CW during the daily port film with the position of the CW during that day's treatment to determine the reproducibility of the breath hold position. Finally, we created competing treatment plans not using DIBH and used a paired t test to compare mean heart (MH) and left anterior descending (LAD) coronary artery dose between the 2 techniques. Mean total error (inter- and intrafraction) was dominated by interfraction error and was greatest in the longitudinal direction with a mean of 2.13 mm and 2 standard deviations of 8.2 mm. DIBH significantly reduced MH and LAD dose versus free breathing plans (MH, 1.26 Gy vs 2.84 Gy, P ≤ .001; LAD, 5.49 Gy vs 18.15 Gy, P ≤ .001). This study demonstrates that DIBH with electromagnetic confirmation of CW position is feasible, and allows potential improvement in the accurate delivery of adjuvant RT therapy for breast cancer. Published by Elsevier Inc.

Electromagnetic interference of dental equipment with implantable cardioverter defibrillators.

PubMed

Dadalti, Manoela Teixeira de Sant'Anna; da Cunha, Antônio José Ledo Alves; Araújo, Marcos César Pimenta de; Moraes, Luis Gustavo Belo de; Risso, Patrícia de Andrade

2017-11-01

Implantable cardioverter defibrillators (ICDs) are subject to electromagnetic interference (EMI). The aim of this study was to assess both the EMI of dental equipments with ICDs and related factors. High- and low-speed handpieces, an electric toothbrush, an implant motor and two types of ultrasonic devices were tested next to an ICD with different sensitivity settings. The ICD was immersed in a saline solution with electrical resistance of 400-800 ohms to simulate the resistance of the human body. The dental equipments were tested in both horizontal (0°) and vertical (90°) positions in relation to the components of the ICD. The tests were performed with a container containing saline solution, which was placed on a dental chair in order to assess the cumulative effect of electromagnetic fields. The dental chair, high- and low-speed handpieces, electric toothbrush, implant motor and ultrasonic devices caused no EMI with the ICD, irrespective of the program set-up or positioning. No cumulative effect of electromagnetic fields was verified. The results of this study suggest that the devices tested are safe for use in patients with an ICD.

Safety and interaction of patients with implantable cardiac defibrillators driving a hybrid vehicle.

PubMed

Tondato, Fernando; Bazzell, Jane; Schwartz, Linda; Mc Donald, Bruce W; Fisher, Robert; Anderson, S Shawn; Galindo, Arcenio; Dueck, Amylou C; Scott, Luis R

2017-01-15

Electromagnetic interference (EMI) can affect the function of implantable cardioverter defibrillators (ICD). Hybrid electric vehicles (HEV) have increased popularity and are a potential source of EMI. Little is known about the in vivo effects of EMI generated by HEV on ICD. This study evaluated the in vivo interaction between EMI generated by HEV with ICD. Thirty patients (73±9 y/o; 80% male) with stable ICD function were exposed to EMI generated by a Toyota Prius Hybrid®. The vehicle was lifted above the ground, allowing safe changes in engine rotation and consequent variations in electromagnetic emission. EMI was measured (NARDA STS® model EHP-50C) and expressed in A/m (magnetic), Volts/m (electrical), and Hertz (frequency). Six positions were evaluated: driver, front passenger, right and left back seats, outside, at the back and front of the car. Each position was evaluated at idle, 30 mph, 60 mph and variable speeds (acceleration-deceleration-brake). All ICD devices were continuously monitored during the study. The levels of EMI generated were low (highest mean levels: 2.09A/m at right back seat at 30 mph; and 3.5V/m at driver seat at variable speeds). No episode of oversensing or inadvertent change in ICD programming was observed. It is safe for patients with ICD to interact with HEV. This is the first study to address this issue using an in vivo model. Further studies are necessary to evaluate the interaction of different models of HEV or electric engine with ICD or unipolar pacemakers. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Electromagnetic transponders indicate prostate size increase followed by decrease during the course of external beam radiation therapy.

PubMed

King, Benjamin L; Butler, Wayne M; Merrick, Gregory S; Kurko, Brian S; Reed, Joshua L; Murray, Brian C; Wallner, Kent E

2011-04-01

Real-time image guidance enables more accurate radiation therapy by tracking target movement. This study used transponder positions to monitor changes in prostate volume that may be a source of dosimetric and target inaccuracy. Twenty-four men with biopsy-proven T1c-T3a prostate cancer each had three electromagnetic transponders implanted transperineally. Their coordinates were recorded by the Calypso system, and the perimeter of the triangle formed by the transponders was used to calculate prostate volumes at sequential time points throughout the course of radiation therapy to a dose of 81 Gy in 1.8-Gy fractions. There was a significant decrease in mean prostate volume of 10.9% from the first to the final day of radiation therapy. The volume loss did not occur monotonically but increased in most patients (75%) during the first several weeks to a median maximum on Day 7. The volume increased by a mean of 6.1% before decreasing by a mean maximum difference of 18.4% to nadir (p < 0.001 for both increase and decrease). Glandular shrinkage was asymmetric, with the apex to right base dimension varying more than twice that of the lateral dimension. For all dimensions, the mean change was <0.5 cm. Real-time transponder positions indicated a volume increase during the initial days of radiation therapy and then significant and asymmetric shrinkage by the final day. Understanding and tracking volume fluctuations of the prostate during radiation therapy can help real-time imaging technology perform to its fullest potential. Copyright © 2011 Elsevier Inc. All rights reserved.

[National system of protection against electromagnetic fields 0 Hz-300 GHz in the light of current legal regulations].

PubMed

Aniołczyk, Halina

2006-01-01

Exposure to electromagnetic fields (EMF) occurs when man is exposed to the effect of electric, magnetic and electromagnetic fields and contact currents different from those resulting from physiological processes in the organism or other natural phenomena. In Poland, the system of protection against EMF has been functioning for over 35 years. In 2001, when the Minister of Labor and Social Policy issued the regulation introducing the maximum admissible intensities (MAI) for electromagnetic fields and radiation within the range of 0 Hz-300 GHz, the system was directed mainly towards evaluation of exposure to EMF occurring in the occupational environment. The system is linked via MAI values with human protection in the natural environment. In this paper, the background, principles and the range of the national system of protection against EMF and its monitoring are presented. The project of implementation of EU directives, following Poland's accession to the European Union is also discussed.

Development and implementation of the software for visualization and analysis of data geophysical loggers

NASA Astrophysics Data System (ADS)

Gordeev, V. F.; Malyshkov, S. Yu.; Botygin, I. A.; Sherstnev, V. S.; Sherstneva, A. I.

2017-11-01

The general trend of modern ecological geophysics is changing priorities towards rapid assessment, management and prediction of ecological and engineering soil stability as well as developing brand new geophysical technologies. The article describes researches conducted by using multi-canal geophysical logger MGR-01 (developed by IMCES SB RAS), which allows to measure flux density of very low-frequency electromagnetic radiation. It is shown that natural pulsed electromagnetic fields of the earthen lithosphere can be a source of new information on Earth's crust and processes in it, including earthquakes. The device is intended for logging electromagnetic processes in Earth's crust, geophysical exploration, finding structural and lithological inhomogeneities, monitoring the geodynamic movement of Earth's crust, express assessment of seismic hazards. The data is gathered automatically from observation point network in Siberia

Effect of electromagnetic field accompanying the magnetic resonance imaging on human heart rate variability - a pilot study.

PubMed

Derkacz, Arkadiusz; Gawrys, Jakub; Gawrys, Karolina; Podgorski, Maciej; Magott-Derkacz, Agnieszka; Poreba, Rafał; Doroszko, Adrian

2018-06-01

The effect of electromagnetic field on cardiovascular system in the literature is defined in ambiguous way. The aim of this study was to evaluate the effect of electromagnetic field on the heart rate variability (HRV) during the examination with magnetic resonance. Forty-two patients underwent Holter ECG heart monitoring for 30 minutes twice: immediately before and after the examination with magnetic resonance imaging (MRI). HRV was analysed by assessing a few selected time and spectral parameters. Is has been shown that standard deviation of NN intervals (SDNN) and very low frequency rates increased, whereas the low frequency:high frequency parameter significantly decreased following the MRI examination. These results show that MRI may affect the HRV most likely by changing the sympathetic-parasympathetic balance.

Spectral changes in stochastic anisotropic electromagnetic beams propagating through turbulent ocean

NASA Astrophysics Data System (ADS)

Tang, Miaomiao; Zhao, Daomu

2014-02-01

Based on the extended Huygens-Fresnel principle and the unified theory of coherence and polarization of light, the spectral changes of stochastic anisotropic electromagnetic beams propagating through oceanic turbulence are revealed. As an example, some numerical calculations are illustrated for an anisotropic electromagnetic Gaussian Schell-model beam propagating in a homogeneous and isotropic turbulent ocean. It is shown that, under the influence of oceanic turbulence, the on-axis spectrum is always blue-shifted along with the propagation distance, however, for the off-axis positions, red-blue spectral switch can be found.

[The influence of electromagnetic fields on flora and fauna].

PubMed

Rochalska, Małgorzata

2009-01-01

This paper presents the influence of natural and artificial electromagnetic fields (EMF) on fauna and flora. The mechanisms of Earth's magnetic field detection and the use of this skill by migratory animals to faultlessly reach the destination of their travel are discussed, as well as the positive effects of electric and magnetic fields on plants relative to their physiology, yielding and health. EMF influence on social insects and animal organisms, including possible DNA damages and DNA repair systems, is presented. The influence of high frequency electromagnetic fields on birds nesting is also discussed.

Energy harvesting from rail track for transportation safety and monitoring.

DOT National Transportation Integrated Search

2014-02-01

An efficient electromagnetic energy harvester featured with mechanical motion rectifier (MMR) is designed to recover : energy from the vibration-like railroad track deflections induced by passing trains. Comparing to typical existing : vibration ener...

Automatic Radiated Susceptibility Test System for Payload Equipment

NASA Technical Reports Server (NTRS)

Ngo, Hoai T.; Sturman, John C.; Sargent, Noel B.

1995-01-01

An automatic radiated susceptibility test system (ARSTS) was developed for NASA Lewis Research Center's Electro-magnetic Interference laboratory. According to MSFC-SPEC 521B, any electrical or electronic equipment that will be transported by the spacelab and space shuttle must be tested for susceptibility to electromagnetic interference. This state-of-the-art automatic test system performs necessary calculations; analyzes, processes, and records a great quantity of measured data; and monitors the equipment being tested in real-time and with minimal user intervention. ARSTS reduces costly test time, increases test accuracy, and provides reliable test results.

EMI Measurement and Mitigation Testing for the ARPA Hybrid Electric Vehicle Program

DTIC Science & Technology

1996-08-27

communication range is reduced, computers malfunction, or monitoring systems fail. Various electric vehicles ( EVs ) were measured to evaluate their...electric vehicles ( EVs ) were measured to evaluate their potential EMI emissions when used in today’s hostile commercial electromagnetic environment...monitoring systems fail. Various electric vehicles ( EVs ) were measured to evaluate their potential EMI emissions when used in today’s hostile commercial

On the feasibility of borehole-to-surface electromagnetics for monitoring CO2 sequestration

NASA Astrophysics Data System (ADS)

Wilson, G. A.; Zhdanov, M. S.; Hibbs, A. D.; Black, N.; Gribenko, A. V.; Cuma, M.; Agundes, A.; Eiskamp, G.

2012-12-01

Carbon capture and storage (CCS) projects rely on storing supercritical CO2 in deep saline reservoirs where buoyancy forces drive the injected CO2 upward into the aquifer until a seal is reached. The permanence of the sequestration depends entirely on the long-term geological integrity of the seal. Active geophysical monitoring of the sequestration is critical for informing CO2 monitoring, accounting and verification (MVA) decisions. During injection, there exists a correlation between the changes in CO2 and water saturations in a saline reservoir. Dissolved salts react with the CO2 to precipitate out as carbonates, thereby generally decreasing the electrical resistivity. As a result, there is a correlation between the change in fluid saturation and measured electromagnetic (EM) fields. The challenge is to design an EM survey appropriate for monitoring large, deep reservoirs. Borehole-to-surface electromagnetic (BSEM) surveys consist of borehole-deployed galvanic transmitters and a surface-based array of electric and magnetic field sensors. During a recent field trial, it was demonstrated that BSEM could successfully identify the oil-water contact in the water-injection zone of a carbonate reservoir. We review the BSEM methodology, and perform full-field BSEM modeling. The 3D resistivity models used in this study are based on dynamic reservoir simulations of CO2 injection into a saline reservoir. Although the electric field response at the earth's surface is low, we demonstrate that it can be accurately measured and processed with novel methods of noise cancellation and sufficient stacking over the period of monitoring to increase the signal-to-noise ratio for subsequent seismic- and well-constrained 3D inversion. For long-term or permanent monitoring, we discuss the deployment of novel electric field sensors with chemically inert electrodes that couple to earth in a capacitive manner. This capacitive coupling is a purely EM phenomenon, which, to first order, has no temperature, ionic concentration or corrosion effects and has unprecedented fidelity. This makes the capacitive E-field sensor ideal for CCS applications which require very stable operation over a wide range of ground temperature and moisture level variation, for extended periods of time.

Abnormal Error Monitoring in Math-Anxious Individuals: Evidence from Error-Related Brain Potentials

PubMed Central

Suárez-Pellicioni, Macarena; Núñez-Peña, María Isabel; Colomé, Àngels

2013-01-01

This study used event-related brain potentials to investigate whether math anxiety is related to abnormal error monitoring processing. Seventeen high math-anxious (HMA) and seventeen low math-anxious (LMA) individuals were presented with a numerical and a classical Stroop task. Groups did not differ in terms of trait or state anxiety. We found enhanced error-related negativity (ERN) in the HMA group when subjects committed an error on the numerical Stroop task, but not on the classical Stroop task. Groups did not differ in terms of the correct-related negativity component (CRN), the error positivity component (Pe), classical behavioral measures or post-error measures. The amplitude of the ERN was negatively related to participants’ math anxiety scores, showing a more negative amplitude as the score increased. Moreover, using standardized low resolution electromagnetic tomography (sLORETA) we found greater activation of the insula in errors on a numerical task as compared to errors in a non-numerical task only for the HMA group. The results were interpreted according to the motivational significance theory of the ERN. PMID:24236212

Real-time monitoring of sucrose, sorbitol, d-glucose and d-fructose concentration by electromagnetic sensing.

PubMed

Harnsoongnoen, Supakorn; Wanthong, Anuwat

2017-10-01

Magnetic sensing at microwave frequencies for real-time monitoring of sucrose, sorbitol, d-glucose and d-fructose concentrations is reported. The sensing element was designed based on a coplanar waveguide (CPW) loaded with a split ring resonator (SRR), which was fabricated on a DiClad 880 substrate with a thickness of 1.6mm and relative permittivity (ε r ) of 2.2. The magnetic sensor was connected to a Vector Network Analyzer (VNA) and the electromagnetic interaction between the samples and sensor was analyzed. The magnitude of the transmission coefficient (S 21 ) was used as an indicator to detect the solution sample concentrations ranging from 0.04 to 0.20g/ml. The experimental results confirmed that the developed system using microwaves for the real-time monitoring of sucrose, sorbitol, d-glucose and d-fructose concentrations gave unique results for each solution type and concentration. Moreover, the proposed sensor has a wide dynamic range, high linearity, fast operation and low-cost. Copyright © 2017 Elsevier Ltd. All rights reserved.

Monitoring of Solar Radiation Intensity using Wireless Sensor Network for Plant Growing

NASA Astrophysics Data System (ADS)

Siregar, B.; Fadli, F.; Andayani, U.; Harahap, LA; Fahmi, F.

2017-01-01

Abstract— Plant growth is highly depending on the sunlight, if the consumption of sunlight is enough, it will grow well. The plant will be green because of its chlorophyll and it can perform photosynthesis at maximum; but if the plants get less sunlight, it will make the plants be yellowing. Radiation is electromagnetic waves that are good for plants, so-called visible light. In the electromagnetic wave spectrum the best wavelength range from 400-700 nm for the plant. A monitoring of sun intensity is needed in order to obtain sufficient solar radiation consumption and provide notification if there is a high radiation. In this study, several sensors and devices were combined such as photosynthetic solar radiation sensors, GSM / GPRS and waspmote as a main board or a microcontroller. The test was carried out on at least three occasions; the system has a stable radiation in the morning with an average of 505.51 micrometers. IN this study, we have successfully developed a monitoring tools for solar radiation intensity applied on plant growth by using wireless sensor network.

Geotechnical sensing using electromagnetic attenuation between radio transceivers

NASA Astrophysics Data System (ADS)

Ghazanfari, Ehsan; Pamukcu, Sibel; Yoon, Suk-Un; Suleiman, Muhannad T.; Cheng, Liang

2012-12-01

Monitoring the onset of a geo-event such as the intrusion of a chemical plume or a slow progressive mass slide that results in marked changes in the physical properties of the host soil could be potentially accomplished using a distributed network of embedded radio transceivers. This paper introduces a new concept of subsurface geo-event monitoring, which takes advantage of the spatial and temporal variations in signal strength of electromagnetic (EM) waves transmitted within the net of distributed radios within a sensing area. Results of experiments in the laboratory and the field demonstrated that variations in EM signal strength could be used to detect physical changes in the subsurface. Changes in selected physical properties of host soil including water content, density, and formation of discontinuities could be discerned from the changes in the signal strength of the transmitted wave between embedded radio transceivers. Good agreement was observed between a theoretical model and the experimental results for inter-transceiver distances less than 55 cm. These results demonstrated a viable new approach for distributed sensing and monitoring of subsurface hazards for civil infrastructure within a networked domain of radio transceivers.

Influence of electrocautery-induced electromagnetic interference on quantitative electroencephalographic monitoring of hypnosis during general anesthesia: comparison between the ADMS® and the BIS VISTATM.

PubMed

Kim, Dae-Hee; Yoo, Ji-Young; Kim, Jong-Yeop; Ahn, Soo-Hwan; Kim, Seongsu; Min, Sang-Kee

2018-04-24

Hypnosis monitors analyze small-amplitude electrical signals transmitted from the brain that could be exposed to the electromagnetic field that occurs around the body during electrocautery (ECT). We investigated the influence of ECT on hypnosis monitoring during anesthesia. We simultaneously monitored BIS and uCON during 50 gynecologic oncology surgeries. During the episodes of ECT, we compared the absolute difference (a-Diff) between the baseline index and the most deviated index after ECT over either 30-60 s (ECT30-60) or more than 60 s (ECT > 60) between the monitors. We also investigated the bias and the limits of agreement between the monitors. Between the two monitors, the a-Diff of ECT30-60 was 1.4 ± 1.1 for the BIS, which was significantly greater than 0.6 ± 0.9 for the uCON (P = 0.003), and the a-Diff of ECT > 60 was 16.5 ± 8.2 for the BIS, which was also significantly greater than 1.4 ± 1.3 for uCON (P < 0.001). The intra-monitor index differences showed that the BIS during ECT > 60 was significantly greater than that during ECT30-60 (P < 0.001), but the uCON showed no significant difference between ECT30-60 and ECT > 60 (P = 0.056). The estimated bias between the monitors was 6.3 ± 9.8 and 95% limits agreement was -12.3 to 25.0. Prolonged ECT intervention might lead to spurious estimations of quantitative EEG indexes. Therefore, hypnosis should be clinically assessed in combination with scrutinized judgment of relevant clinical symptoms and signs for hypnosis.

A Comparative Study of the Precision of Carstens and Northern Digital Instruments Electromagnetic Articulographs

ERIC Educational Resources Information Center

Savariaux, Christophe; Badin, Pierre; Samson, Adeline; Gerber, Silvain

2017-01-01

Purpose: This study compares the precision of the electromagnetic articulographs used in speech research: Northern Digital Instruments' Wave and Carstens' AG200, AG500, and AG501 systems. Method: The fluctuation of distances between 3 pairs of sensors attached to a manually rotated device that can position them inside the measurement volumes was…

[Effect of electromagnetic radiation on discharge activity of neurons in the hippocampus CA1 in rats].

PubMed

Tong, Jun; Chen, Su; Liu, Xiang-Ming; Hao, Dong-Mei

2013-09-01

In order to explore effect of electromagnetic radiation on learning and memory ability of hippocampus neuron in rats, the changes in discharge patterns and overall electrical activity of hippocampus neuron after electromagnetic radiation were observed. Rat neurons discharge was recorded with glass electrode extracellular recording technology and a polygraph respectively. Radiation frequency of electromagnetic wave was 900 MHZ and the power was 10 W/m2. In glass electrode extracellular recording, the rats were separately irradiated for 10, 20, 30, 40, 50 and 60 min, every points repeated 10 times and updated interval of 1h, observing the changes in neuron discharge and spontaneous discharge patterns after electromagnetic radiation. In polygraph recording experiments, irradiation group rats for five days a week, 6 hours per day, repeatedly for 10 weeks, memory electrical changes in control group and irradiation group rats when they were feeding were repeatedly monitored by the implanted electrodes, observing the changes in peak electric digits and the largest amplitude in hippocampal CA1 area, and taking some electromagnetic radiation sampling sequence for correlation analysis. (1) Electromagnetic radiation had an inhibitory role on discharge frequency of the hippocampus CA1 region neurons. After electromagnetic radiation, discharge frequency of the hippocampus CA1 region neurons was reduced, but the changes in scale was not obvious. (2) Electromagnetic radiation might change the spontaneous discharge patterns of hippocampus CA1 region neurons, which made the explosive discharge pattern increased obviously. (3) Peak potential total number within 5 min in irradiation group was significantly reduced, the largest amplitude was less than that of control group. (4) Using mathematical method to make the correlation analysis of the electromagnetic radiation sampling sequence, that of irradiation group was less than that of control group, indicating that there was a tending to be inhibitory connection between neurons in irradiation group after electromagnetic radiation. Electromagnetic radiation may cause structure and function changes of transfer synaptic in global, make hippocampal CA1 area neurons change in the overall discharge characteristic and discharge patterns, thus lead to decrease in the ability of learning and memory.

Ultrastructural Study on Ultra-Low Frequency Electromagnetic Fields and Transfer Factor Effects on Skin Ulcers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cadena, M. S. Reyes; Chapul, L. Sanchez; Perez, Javier

2008-08-11

We determined the effect of 120Hz ultra low frequency electromagnetic field (ELF) on the healing process of skin in 20 Wistar rats distributed in four groups in which chronic dermal ulcers had been produced. The first two groups received a dose of the transfer factor and interferon-beta (IFN-{beta}) every 24 h during 12 days. The third group (positive control) received only electromagnetic field (ELF) sessions, and in the fourth group (negative control), no treatment was applied. The electromagnetic field was applied through a Helmholtz coils; 30 Gauss of intensity. Results shown histological changes that improve the healing process in animalsmore » subjected to ELF together with the transfer factor.« less

Radiation dosimeter utilizing the thermoluminescence of lithium fluoride.

PubMed

CAMERON, J R; DANIELS, F; JOHNSON, N; KENNEY, G

1961-08-04

A dosimeter, with little wavelength dependence and large useful energy range for electromagnetic radiation, which is simple to use and read, has been developed. It appears to have applications in personnel monitoring as well as radiation research.

Basic Principles of Spectroscopy

NASA Astrophysics Data System (ADS)

Penner, Michael H.

Spectroscopy deals with the production, measurement, and interpretation of spectra arising from the interaction of electromagnetic radiation with matter. There are many different spectroscopic methods available for solving a wide range of analytical problems. The methods differ with respect to the species to be analyzed (such as molecular or atomic spectroscopy), the type of radiation-matter interaction to be monitored (such as absorption, emission, or diffraction), and the region of the electromagnetic spectrum used in the analysis. Spectroscopic methods are very informative and widely used for both quantitative and qualitative analyses. Spectroscopic methods based on the absorption or emission of radiation in the ultraviolet (UV), visible (Vis), infrared (IR), and radio (nuclear magnetic resonance, NMR) frequency ranges are most commonly encountered in traditional food analysis laboratories. Each of these methods is distinct in that it monitors different types of molecular or atomic transitions. The basis of these transitions is explained in the following sections.

The Use of a Gain Monitoring System in the G0 Experiment

NASA Astrophysics Data System (ADS)

Nakos, Melissa T.

2001-11-01

The main goal of the G0 experiment is to find the contributions of the three light quark flavors to the electromagnetic properties of the nucleon by comparing the electromagnetic and neutral weak form factors, measured through the observation of parity-violating asymmetries in elastic electron-nucleon scattering. The experiment will measure the time of flight and the momentum transfer of protons (at forward scattering angles) and electrons (at backward scattering angles). The detectors used in this experiment are plastic scintillators placed in the focal plane of a magnetic spectrometer such that the momentum transfer is directly measured. A gain monitoring system has been designed to track the timing and gain of the photomultiplier tubes at the end of each scintillator. The system is made of a pulsed ultraviolet laser, pure silica fiber optic cables, and a masking system to mimic a real event.

Superiority of terahertz over infrared transmission through bandages and burn wound ointments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suen, Jonathan Y., E-mail: j.suen@duke.edu; Padilla, Willie J.

Terahertz electromagnetic waves have long been proposed to be ideal for spectroscopy and imaging through non-polar dielectric materials that contain no water. Terahertz radiation may thus be useful for monitoring burn and wound injury recovery, as common care treatments involve application of both a clinical dressing and topical ointment. Here, we investigate the optical properties of typical care treatments in the millimeter wave (150–300 GHz), terahertz (0.3–3 THz), and infrared (14.5–0.67 μm) ranges of the electromagnetic spectrum. We find that THz radiation realizes low absorption coefficients and high levels of transmission compared to infrared wavelengths, which were strongly attenuated. Terahertz imaging canmore » enable safe, non-ionizing, noninvasive monitoring of the healing process directly through clinical dressings and recovery ointments, minimizing the frequency of dressing changes and thus increasing the rate of the healing process.« less

Condition monitoring of an electro-magnetic brake using an artificial neural network

NASA Astrophysics Data System (ADS)

Gofran, T.; Neugebauer, P.; Schramm, D.

2017-10-01

This paper presents a data-driven approach to Condition Monitoring of Electromagnetic brakes without use of additional sensors. For safe and efficient operation of electric motor a regular evaluation and replacement of the friction surface of the brake is required. One such evaluation method consists of direct or indirect sensing of the air-gap between pressure plate and magnet. A larger gap is generally indicative of worn surface(s). Traditionally this has been accomplished by the use of additional sensors - making existing systems complex, cost- sensitive and difficult to maintain. In this work a feed-forward Artificial Neural Network (ANN) is learned with the electrical data of the brake by supervised learning method to estimate the air-gap. The ANN model is optimized on the training set and validated using the test set. The experimental results of estimated air-gap with accuracy of over 95% demonstrate the validity of the proposed approach.

Multiple bio-monitoring system using visible light for electromagnetic-wave free indoor healthcare

NASA Astrophysics Data System (ADS)

An, Jinyoung; Pham, Ngoc Quan; Chung, Wan-Young

2017-12-01

In this paper, a multiple biomedical data transmission system with visible light communication (VLC) is proposed for an electromagnetic-wave-free indoor healthcare. VLC technology has emerged as an alternative solution to radio-frequency (RF) wireless systems, due to its various merits, e.g., ubiquity, power efficiency, no RF radiation, and security. With VLC, critical bio-medical signals, including electrocardiography (ECG), can be transmitted in places where RF radiation is restricted. This potential advantage of VLC could save more lives in emergency situations. A time hopping (TH) scheme is employed to transfer multiple medical-data streams in real time with a simple system design. Multiple data streams are transmitted using identical color LEDs and go into an optical detector. The received multiple data streams are demodulated and rearranged using a TH-based demodulator. The medical data is then monitored and managed to provide the necessary medical care for each patient.

Seismic wave generation systems and methods for cased wells

DOEpatents

Minto, James [Houston, TX; Sorrells, Martin H [Huffman, TX; Owen, Thomas E [Helotes, TX; Schroeder, Edgar C [San Antonio, TX

2011-03-29

A vibration source (10) includes an armature bar (12) having a major length dimension, and a driver (20A) positioned about the armature bar. The driver (20A) is movably coupled to the armature bar (12), and includes an electromagnet (40). During operation the electromagnet (40) is activated such that the driver (20A) moves with respect to the armature bar (12) and a vibratory signal is generated in the armature bar. A described method for generating a vibratory signal in an object includes positioning the vibration source (10) in an opening of the object, coupling the armature bar (12) to a surface of the object within the opening, and activating the electromagnet (40) of the driver (20A) such that the driver moves with respect to the armature bar (12) and a vibratory signal is generated in the armature bar and the object.

Narrow field electromagnetic sensor system and method

DOEpatents

McEwan, Thomas E.

1996-01-01

A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments.

Narrow field electromagnetic sensor system and method

DOEpatents

McEwan, T.E.

1996-11-19

A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments. 12 figs.

Level monitoring system with pulsating sensor—Application to online level monitoring of dashpots in a fast breeder reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malathi, N.; Sahoo, P., E-mail: sahoop@igcar.gov.in; Ananthanarayanan, R.

2015-02-15

An innovative continuous type liquid level monitoring system constructed by using a new class of sensor, viz., pulsating sensor, is presented. This device is of industrial grade and it is exclusively used for level monitoring of any non conducting liquid. This instrument of unique design is suitable for high resolution online monitoring of oil level in dashpots of a sodium-cooled fast breeder reactor. The sensing probe is of capacitance type robust probe consisting of a number of rectangular mirror polished stainless steel (SS-304) plates separated with uniform gaps. The performance of this novel instrument has been thoroughly investigated. The precision,more » sensitivity, response time, and the lowest detection limit in measurement using this device are <0.01 mm, ∼100 Hz/mm, ∼1 s, and ∼0.03 mm, respectively. The influence of temperature on liquid level is studied and the temperature compensation is provided in the instrument. The instrument qualified all recommended tests, such as environmental, electromagnetic interference and electromagnetic compatibility, and seismic tests prior to its deployment in nuclear reactor. With the evolution of this level measurement approach, it is possible to provide dashpot oil level sensors in fast breeder reactor for the first time for continuous measurement of oil level in dashpots of Control and Safety Rod Drive Mechanism during reactor operation.« less

WE-A-17A-09: Exploiting Electromagnetic Technologies for Real-Time Seed Drop Position Validation in Permanent Implant Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Racine, E; Hautvast, G; Binnekamp, D

Purpose: To report on preliminary results validating the performance of a specially designed LDR brachytherapy needle prototype possessing both electromagnetic (EM) tracking and seed drop detection abilities. Methods: An EM hollow needle prototype has been designed and constructed in collaboration with research partner Philips Healthcare. The needle possesses conventional 3D tracking capabilities, along with a novel seed drop detection mechanism exploiting local changes of electromagnetic properties generated by the passage of seeds in the needle's embedded sensor coils. These two capabilities are exploited by proprietary engineering and signal processing techniques to generate seed drop position estimates in real-time treatment delivery.more » The electromagnetic tracking system (EMTS) used for the experiment is the NDI Aurora Planar Field Generator. The experiment consisted of dropping a total of 35 seeds in a prismatic agarose phantom, and comparing the 3D seed drop positions of the EMTS to those obtained by an image analysis of subsequent micro-CT scans. Drop position error computations and statistical analysis were performed after a 3D registration of the two seed distributions. Results: Of the 35 seeds dropped in the phantom, 32 were properly detected by the needle prototype. Absolute drop position errors among the detected seeds ranged from 0.5 to 4.8 mm with mean and standard deviation values of 1.6 and 0.9 mm, respectively. Error measurements also include undesirable and uncontrollable effects such as seed motion upon deposition. The true accuracy performance of the needle prototype is therefore underestimated. Conclusion: This preliminary study demonstrates the potential benefits of EM technologies in detecting the passage of seeds in a hollow needle as a means of generating drop position estimates in real-time treatment delivery. Such tools could therefore represent a potentially interesting addition to existing brachytherapy protocols for rapid dosimetry validation. Equipments and fundings for this project were provided by Philips Medical.« less

Electromagnetic attachment mechanism

NASA Technical Reports Server (NTRS)

Monford, Leo G., Jr. (Inventor)

1992-01-01

An electromagnetic attachment mechanism is disclosed for use as an end effector of a remote manipulator system. A pair of electromagnets, each with a U-shaped magnetic core with a pull-in coil and two holding coils, are mounted by a spring suspension system on a base plate of the mechanism housing with end pole pieces adapted to move through openings in the base plate when the attractive force of the electromagnets is exerted on a strike plate of a grapple fixture affixed to a target object. The pole pieces are spaced by an air gap from the strike plate when the mechanism first contacts the grapple fixture. An individual control circuit and power source is provided for the pull-in coil and one holding coil of each electromagnet. A back-up control circuit connected to the two power sources and a third power source is provided for the remaining holding coils. When energized, the pull-in coils overcome the suspension system and air gap and are automatically de-energized when the pole pieces move to grapple and impose a preload force across the grapple interface. A battery backup is a redundant power source for each electromagnet in each individual control circuit and is automatically connected upon failure of the primary source. A centerline mounted camera and video monitor are used in cooperation with a target pattern on the reflective surface of the strike plate to effect targeting and alignment.

Comparison of the Effects of Manual Acupuncture, Laser Acupuncture, and Electromagnetic Field Stimulation at Acupuncture Point BL15 on Heart Rate Variability.

PubMed

Lee, Na Ra; Kim, Soo Byeong; Heo, Hyun; Lee, Yong Heum

2016-10-01

The aim of this study was to compare the influences of manual acupuncture, laser acupuncture, and electromagnetic field stimulation on the autonomic nervous system. We monitored the heart rate variability before and after stimulation to check the influence on the autonomic nervous system. The heart rate variabilities at low frequency (LF; 0.04-0.15 Hz) and high frequency (HF; 0.15-0.4 Hz) were analyzed to acquire LF/HF ratio. Xinshu (BL15) was selected as the stimulation point. Methods included manual acupuncture with a 1-cm depth and laser acupuncture at a wavelength of 660 nm and output power of 50 mW. An electromagnetic field of 2 Hz and 460 gauss (46 mT) was chosen. The LF and the LF/HF ratio were found to be lower in the manual acupuncture and the electromagnetic field groups, but to be higher in the laser acupuncture group. The HF was found to be lower in the laser acupuncture group, but higher in the manual acupuncture and the electromagnetic field groups. In conclusion, we found that manual acupuncture and electromagnetic field stimulation at BL15 activated the parasympathetic nervous system, whereas laser acupuncture at BL15 activated the sympathetic nervous system. Copyright © 2016. Published by Elsevier B.V.

Modeling and Evaluation of Geophysical Methods for Monitoring and Tracking CO2 Migration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daniels, Jeff

2012-11-30

Geological sequestration has been proposed as a viable option for mitigating the vast amount of CO{sub 2} being released into the atmosphere daily. Test sites for CO{sub 2} injection have been appearing across the world to ascertain the feasibility of capturing and sequestering carbon dioxide. A major concern with full scale implementation is monitoring and verifying the permanence of injected CO{sub 2}. Geophysical methods, an exploration industry standard, are non-invasive imaging techniques that can be implemented to address that concern. Geophysical methods, seismic and electromagnetic, play a crucial role in monitoring the subsurface pre- and post-injection. Seismic techniques have beenmore » the most popular but electromagnetic methods are gaining interest. The primary goal of this project was to develop a new geophysical tool, a software program called GphyzCO2, to investigate the implementation of geophysical monitoring for detecting injected CO{sub 2} at test sites. The GphyzCO2 software consists of interconnected programs that encompass well logging, seismic, and electromagnetic methods. The software enables users to design and execute 3D surface-to-surface (conventional surface seismic) and borehole-to-borehole (cross-hole seismic and electromagnetic methods) numerical modeling surveys. The generalized flow of the program begins with building a complex 3D subsurface geological model, assigning properties to the models that mimic a potential CO{sub 2} injection site, numerically forward model a geophysical survey, and analyze the results. A test site located in Warren County, Ohio was selected as the test site for the full implementation of GphyzCO2. Specific interest was placed on a potential reservoir target, the Mount Simon Sandstone, and cap rock, the Eau Claire Formation. Analysis of the test site included well log data, physical property measurements (porosity), core sample resistivity measurements, calculating electrical permittivity values, seismic data collection, and seismic interpretation. The data was input into GphyzCO2 to demonstrate a full implementation of the software capabilities. Part of the implementation investigated the limits of using geophysical methods to monitor CO{sub 2} injection sites. The results show that cross-hole EM numerical surveys are limited to under 100 meter borehole separation. Those results were utilized in executing numerical EM surveys that contain hypothetical CO{sub 2} injections. The outcome of the forward modeling shows that EM methods can detect the presence of CO{sub 2}.« less

Electromagnet Weight Reduction in a Magnetic Levitation System for Contactless Delivery Applications

PubMed Central

Hong, Do-Kwan; Woo, Byung-Chul; Koo, Dae-Hyun; Lee, Ki-Chang

2010-01-01

This paper presents an optimum design of a lightweight vehicle levitation electromagnet, which also provides a passive guide force in a magnetic levitation system for contactless delivery applications. The split alignment of C-shaped electromagnets about C-shaped rails has a bad effect on the lateral deviation force, therefore, no-split positioning of electromagnets is better for lateral performance. This is verified by simulations and experiments. This paper presents a statistically optimized design with a high number of the design variables to reduce the weight of the electromagnet under the constraint of normal force using response surface methodology (RSM) and the kriging interpolation method. 2D and 3D magnetostatic analysis of the electromagnet are performed using ANSYS. The most effective design variables are extracted by a Pareto chart. The most desirable set is determined and the influence of each design variable on the objective function can be obtained. The generalized reduced gradient (GRG) algorithm is adopted in the kriging model. This paper’s procedure is validated by a comparison between experimental and calculation results, which shows that the predicted performance of the electromagnet designed by RSM is in good agreement with the simulation results. PMID:22163572

Compilation of 1990 annual reports of the Navy ELF communications system ecological monitoring program. Volume 3: Tabs G thru I

NASA Astrophysics Data System (ADS)

Zapotosky, J. E.

1991-08-01

This portion of the report includes monitoring of and data for bird species and communities, aquatic ecosystem and a listing of technical reports. Effects of extremely-low-frequency electromagnetic fields on most aspects of a bird species' life history are poorly understood. This investigation was designed to isolate effects of EM fields produced by ELF antenna systems on bird species breeding in or migrating through Wisconsin and Michigan. Specifically, we seek to determine if bird species richness and abundance differ between areas that are close to the antenna and those that are far enough away to be unaffected by the antenna. The goal of the aquatic ecosystems portion of the project is to determine the effects of low-level, long-term, electromagnetic radiation on the biota of streams. This electromagnetic radiation will be derived from the U.S. Navy's extremely low frequency submarine communication system (ELF) located in the upper peninsula of Michigan. The specific ecosystem being studied is the Ford River, a fourth order stream that arises in northern Dickinson and southern Marquette Counties and enters the Michigan portion of Green Bay south of Escanaba, Michigan. Detailed ecological sample and analyses are being conducted simutaneously at two sites.

Real Time Quality Control Methods for Cued EMI Data Collection

DTIC Science & Technology

2016-03-14

contents be construed as reflecting the official policy or position of the Department of Defense. Reference herein to any specific commercial product...This project evaluated the effectiveness of in-field quality control (QC) procedures during cued electromagnetic induction (EMI) data collection. The...electromagnetic induction ESTCP Environmental Security Technology Certification Program hr hour ISO Industry Standard Object IVS Instrument

Electromagnetic properties of material coated surfaces

NASA Technical Reports Server (NTRS)

Beard, L.; Berrie, J.; Burkholder, R.; Dominek, A.; Walton, E.; Wang, N.

1989-01-01

The electromagnetic properties of material coated conducting surfaces were investigated. The coating geometries consist of uniform layers over a planar surface, irregularly shaped formations near edges and randomly positioned, electrically small, irregularly shaped formations over a surface. Techniques to measure the scattered field and constitutive parameters from these geometries were studied. The significance of the scattered field from these geometries warrants further study.

A study to identify research issues in the area of electromagnetic measurements and signal handling of remotely sensed data

NASA Technical Reports Server (NTRS)

1982-01-01

Research issues in the area of electromagnetic measurements and signal handling of remotely sensed data are identified. The following seven issues are discussed; platform/sensor system position and velocity, platform/sensor attitudes and attitude rates, optics and antennas, detectors and associated electronics, sensor calibration, signal handling, and system design.

The effect of transponder motion on the accuracy of the Calypso Electromagnetic localization system.

PubMed

Murphy, Martin J; Eidens, Richard; Vertatschitsch, Edward; Wright, J Nelson

2008-09-01

To determine position and velocity-dependent effects in the overall accuracy of the Calypso Electromagnetic localization system, under conditions that emulate transponder motion during normal free breathing. Three localization transponders were mounted on a remote-controlled turntable that could move the transponders along a circular trajectory at speeds up to 3 cm/s. A stationary calibration established the coordinates of multiple points on each transponder's circular path. Position measurements taken while the transponders were in motion at a constant speed were then compared with the stationary coordinates. No statistically significant changes in the transponder positions in (x,y,z) were detected when the transponders were in motion. The accuracy of the localization system is unaffected by transponder motion.

Compilation of 1989 annual reports of the Navy ELF Communications System Ecological Monitoring Program. Volume 2. tabs C-F. Annual progress report, Jan-Dec 89

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-08-01

This is the eighth compilation of annual reports for the Navy's ELF Communications Systems Ecological Monitoring Program. The reports document the progress of eight studies performed during 1989 near the Naval Radio Transmitting Facility -- Republic, Michigan. The purpose of the monitoring is to determine whether electromagnetic fields produced by the ELF Communications System will affect resident biota or their ecological relationships. Soil Amoeba: Arthropoda and Earthworms: Pollinating Insects: Small Mammals and Nesting Birds.

Growth Stimulation of Biological Cells and Tissue by Electromagnetic Fields and Uses Thereof

NASA Technical Reports Server (NTRS)

Wolf, David A. (Inventor); Goodwin, Thomas J. (Inventor)

2002-01-01

The present invention provides systems for growing two or three dimensional mammalian cells within a culture medium facilitated by an electromagnetic field, and preferably, a time varying electromagnetic field. The cells, and culture medium are contained within a fixed or rotating culture vessel, and the electromagnetic field is emitted from at least one electrode. In one embodiment, the electrode is spaced from the vessel. The invention further provides methods to promote neural tissue regeneration by means of culturing the neural cells in the claimed system. In one embodiment, neuronal cells are grown within longitudinally extending tissue strands extending axially along and within electrodes comprising electrically conductive channels or guides through which a time varying electrical current is conducted, the conductive channels being positioned within a culture medium.

Growth stimulation of biological cells and tissue by electromagnetic fields and uses thereof

NASA Technical Reports Server (NTRS)

Wolf, David A. (Inventor); Goodwin, Thomas J. (Inventor)

2004-01-01

The present invention provides systems for growing two or three dimensional mammalian cells within a culture medium facilitated by an electromagnetic field, and preferably, a time varying electromagnetic field. The cells and culture medium are contained within a fixed or rotating culture vessel, and the electromagnetic field is emitted from at least one electrode. In one embodiment, the electrode is spaced from the vessel. The invention further provides methods to promote neural tissue regeneration by means of culturing the neural cells in the claimed system. In one embodiment, neuronal cells are grown within longitudinally extending tissue strands extending axially along and within electrodes comprising electrically conductive channels or guides through which a time varying electrical current is conducted, the conductive channels being positioned within a culture medium.

Monitoring Engine Vibrations And Spectrum Of Exhaust

NASA Technical Reports Server (NTRS)

Martinez, Carol L.; Randall, Michael R.; Reinert, John W.

1991-01-01

Real-time computation of intensities of peaks in visible-light emission spectrum of exhaust combined with real-time spectrum analysis of vibrations into developmental monitoring technique providing up-to-the-second information on conditions of critical bearings in engine. Conceived to monitor conditions of bearings in turbopump suppling oxygen to Space Shuttle main engine, based on observations that both vibrations in bearings and intensities of visible light emitted at specific wavelengths by exhaust plume of engine indicate wear and incipient failure of bearings. Applicable to monitoring "health" of other machinery via spectra of vibrations and electromagnetic emissions from exhausts. Concept related to one described in "Monitoring Bearing Vibrations For Signs Of Damage", (MFS-29734).

EMF Monitoring on Amtrak's Northeast Corridor : Post-Electrification Measurement and Analysis

DOT National Transportation Integrated Search

2006-10-01

This survey of electromagnetic fields (EMF) and radiation (EMR) due to the electrification infrastructure and operations of Amtrak Acela trains on the Northeast Corridor from New Haven, CT, to Boston, MA, was performed by Electric Research & Manageme...

Soil water sensor response to bulk electrical conductivity

USDA-ARS?s Scientific Manuscript database

Soil water monitoring using electromagnetic (EM) sensors can facilitate observations of water content at high temporal and spatial resolutions. These sensors measure soil dielectric permittivity (Ka) which is largely a function of volumetric water content. However, bulk electrical conductivity BEC c...

An electromagnetic method for removing the communication blackout with a space vehicle upon re-entry into the atmosphere

NASA Astrophysics Data System (ADS)

Cheng, Jianjun; Jin, Ke; Kou, Yong; Hu, Ruifeng; Zheng, Xiaojing

2017-03-01

When a hypersonic vehicle travels in the Earth and Mars atmosphere, the surface of the vehicle is surrounded by a plasma layer, which is an envelope of ionized air, created from the compression and heat of the atmosphere by the shock wave. The vehicles will lose contact with ground stations known as the reentry communication blackout. Based on the magnetohydrodynamic framework and electromagnetic wave propagation theory, an analytical model is proposed to describe the effect of the effectiveness of electromagnetic mitigation scheme on removing the reentry communication blackout. C and Global Positioning System (GPS) bands, two commonly used radio bands for communication, are taken as the cases to discuss the effectiveness of the electromagnetic field mitigation scheme. The results show that the electron density near the antenna of vehicles can be reduced by the electromagnetic field, and the required external magnetic field strength is far below the one in the magnetic window method. The directions of the external electric field and magnetic field have a significant impact on the effectiveness of the mitigation scheme. Furthermore, the effect of electron collisions on the required applied electromagnetic field is discussed, and the result indicates that electron collisions are a key factor to analyze the electromagnetic mitigation scheme. Finally, the feasible regions of the applied electromagnetic field for eliminating blackout are given. These investigations could have a significant benefit on the design and optimization of electromagnetic mitigation scheme for the blackout problem.

Electromagnetic interference of endodontic equipments with cardiovascular implantable electronic device.

PubMed

Dadalti, Manoela Teixeira de Sant'Anna; da Cunha, Antônio José Ledo Alves; de Araújo, Marcos César Pimenta; de Moraes, Luis Gustavo Belo; Risso, Patrícia de Andrade

2016-03-01

Assess the electromagnetic interference (EMI) of endodontic equipment with cardiovascular implantable electronic devices (CIEDs) and related factors. The laser device, electronic apex locators (EAL), optical microscope, endodontic rotary motors, gutta-percha heat carrier (GH), gutta-percha gun and ultrasonic device were tested next to CIEDs (Medtronic and Biotronik) with varied sensitivity settings and distances. CIEDs were immersed in a saline solution to simulate the electrical resistence of the human body. The endodontic equipment was tested in both horizontal and vertical positions in relation to the components of the CIED. The tests were performed on a dental chair in order to assess the cumulative effect of electromagnetic fields. It was found no EMI with the Biotronik pacemaker. EALs caused EMI with Medtronic PM at a 2 cm distance, with the NSK(®) EAL also affecting the Medtronic defibrillator. GH caused EMI at 2 cm and 5 cm from the Medtronic defibrillator. EMI occurred when devices were horizontally positioned to the CIED. In the majority of the cases, EMI occurred when the pacemaker was set to maximum sensitivity. There was cumulative effect of electromagnetic fields between GH and dental chair. EALs and GH caused EMI which ranged according to type and sensitivity setting of the CIEDs and the distance. However, no endodontic equipment caused permanent damage to the CIED. The use of GH caused a cumulative effect of electromagnetic fields. It suggests that during the treatment of patients with CIEDs, only the necessary equipments should be kept turned on. Patients with CIEDs may be subject to EMI from electronic equipment used in dental offices, as they remain turned on throughout the treatment. This is the first article assessing the cumulative effect of electromagnetic fields. Copyright © 2016. Published by Elsevier Ltd.

Magnet-Based System for Docking of Miniature Spacecraft

NASA Technical Reports Server (NTRS)

Howard, Nathan; Nguyen, Hai D.

2007-01-01

A prototype system for docking a miniature spacecraft with a larger spacecraft has been developed by engineers at the Johnson Space Center. Engineers working on Mini AERCam, a free-flying robotic camera, needed to find a way to successfully dock and undock their miniature spacecraft to refuel the propulsion and recharge the batteries. The subsystems developed (see figure) include (1) a docking port, designed for the larger spacecraft, which contains an electromagnet, a ball lock mechanism, and a service probe; and (2) a docking cluster, designed for the smaller spacecraft, which contains either a permanent magnet or an electromagnet. A typical docking operation begins with the docking spacecraft maneuvering into position near the docking port on the parent vehicle. The electromagnet( s) are then turned on, and, if necessary, the docking spacecraft is then maneuvered within the capture envelope of the docking port. The capture envelope for this system is approximated by a 5-in. (12.7-cm) cube centered on the front of the docking-port electromagnet and within an angular misalignment of <30 . Thereafter, the magnetic forces draw the smaller spacecraft toward the larger one and this brings the spacecraft into approximate alignment prior to contact. Mechanical alignment guides provide the final rotational alignment into one of 12 positions. Once the docking vehicle has been captured magnetically in the docking port, the ball-lock mechanism is activated, which locks the two spacecraft together. At this point the electromagnet( s) are turned off, and the service probe extended if recharge and refueling are to be performed. Additionally, during undocking, the polarity of one electromagnet can be reversed to provide a gentle push to separate the two spacecraft. This system is currently being incorporated into the design of Mini AERCam vehicle.

Comparison of free-hand fluoroscopic guidance and electromagnetic navigation in distal locking of femoral intramedullary nails

PubMed Central

Han, Bing; Shi, Zhigang; Fu, Yu; Ye, Yong; Jing, Juehua; Li, Jun

2017-01-01

Abstract Background: Although the method has been used widely, one of the greatest challenges for intramedullary nailing is to position the distal locking screw. A new technology, the electromagnetic navigation system, is a radiation-free way to locate the position of the drill bit and provide 3-dimensional real-time feedback of location and orientation of the drill bit relative to the locking holes. The purpose of our study was to evaluate the reliability and efficiency of the free-hand technique compared to the new electromagnetic navigation system. Methods: Fifty-four patients with femoral fracture who needed treatment with intramedullary nails were divided into 2 groups. One group including 26 patients underwent distal locking using the standard free-hand method, whereas the electromagnetic navigation system was used with the other 29 patients. Intraoperative fluoroscopy exposure times, screw insertion times, and healing times were recorded; these parameters were used for comparison between the 2 groups. Results: There were 17 males and 9 females who had femoral intramedullary nails using the free-hand technique, whereas 21 males and 8 females received intramedullary nails using the electromagnetic navigation system. The mean time of distal locking was 19.5 ± 6.0 minutes in the free-hand (FH) group, whereas the time was 6.1 ± 1.4 minutes in the electromagnetic (ET) group. The exposure time for the FH group was 26.8 ± 13.3 seconds and 2.2 ± 1.1 seconds for the ET group. Healing time proved to be comparable in the FH and ET groups (16.4 ± 3.7 weeks vs 15.1 ± 2.8 weeks). Conclusion: Under the premise of achieving the same effect, the electromagnetic navigation system has the advantage of less distal locking time and less radiation dose. PMID:28723755

Comparison of free-hand fluoroscopic guidance and electromagnetic navigation in distal locking of femoral intramedullary nails.

PubMed

Han, Bing; Shi, Zhigang; Fu, Yu; Ye, Yong; Jing, Juehua; Li, Jun

2017-07-01

Although the method has been used widely, one of the greatest challenges for intramedullary nailing is to position the distal locking screw. A new technology, the electromagnetic navigation system, is a radiation-free way to locate the position of the drill bit and provide 3-dimensional real-time feedback of location and orientation of the drill bit relative to the locking holes. The purpose of our study was to evaluate the reliability and efficiency of the free-hand technique compared to the new electromagnetic navigation system. Fifty-four patients with femoral fracture who needed treatment with intramedullary nails were divided into 2 groups. One group including 26 patients underwent distal locking using the standard free-hand method, whereas the electromagnetic navigation system was used with the other 29 patients. Intraoperative fluoroscopy exposure times, screw insertion times, and healing times were recorded; these parameters were used for comparison between the 2 groups. There were 17 males and 9 females who had femoral intramedullary nails using the free-hand technique, whereas 21 males and 8 females received intramedullary nails using the electromagnetic navigation system. The mean time of distal locking was 19.5 ± 6.0 minutes in the free-hand (FH) group, whereas the time was 6.1 ± 1.4 minutes in the electromagnetic (ET) group. The exposure time for the FH group was 26.8 ± 13.3 seconds and 2.2 ± 1.1 seconds for the ET group. Healing time proved to be comparable in the FH and ET groups (16.4 ± 3.7 weeks vs 15.1 ± 2.8 weeks). Under the premise of achieving the same effect, the electromagnetic navigation system has the advantage of less distal locking time and less radiation dose.

Luminous phenomena and electromagnetic VHF wave emission originated from earthquake-related radon exhalation

NASA Astrophysics Data System (ADS)

Seki, A.; Tobo, I.; Omori, Y.; Muto, J.; Nagahama, H.

2013-12-01

Anomalous luminous phenomena and electromagnetic wave emission before or during earthquakes have been reported (e.g., the 1965 Matsushiro earthquake swarm). However, their mechanism is still unsolved, in spite of many models for these phenomena. Here, we propose a new model about luminous phenomena and electromagnetic wave emission during earthquake by focusing on atmospheric radon (Rn-222) and its daughter nuclides (Po-218 and Po-214). Rn-222, Po-218 and Po-214 are alpha emitters, and these alpha particles ionize atmospheric molecules. A light emission phenomenon, called 'the air luminescence', is caused by de-excitation of the ionized molecules of atmospheric nitrogen due to electron impact ionization from alpha particles. The de-excitation is from the second positive system of neutral nitrogen molecules and the first negative system of nitrogen molecule ion. Wavelengths of lights by these transitions include the visible light wavelength. So based on this mechanism, we proposed a new luminous phenomenon model before or during earthquake: 1. The concentration of atmospheric radon and its daughter nuclides increase anomalously before or during earthquakes, 2. Nitrogen molecules and their ions are excited by alpha particles emitted from Rn-222, Po-218 and Po-214, and air luminescence is generated by their de-excitation. Similarly, electromagnetic VHF wave emission can be explained by ionizing effect of radon and its daughter nuclides. Boyarchuk et al. (2005) proposed a model that electromagnetic VHF wave emission is originated when excited state of neutral clusters changes. Radon gas ionizes atmosphere and forms positively and negatively charged heavy particles. The process of ion hydration in ordinary air can be determined by the formation of complex chemically active structures of the various types of ion radicals. As a result of the association of such hydration radical ions, a neutral cluster, which is dipole quasi-molecules, is formed. A neutral cluster's rotation-rotation transition causes electromagnetic VHF wave emission. We also discuss a possibility of electromagnetic VHF wave emission from excitation of polyatomic molecules by alpha particles from Rn-222 and its daughter nuclides, similar to air luminescence by excitation of nitrogen molecule in the viewpoint of electromagnetic radiation in quantum theory.

Comparison of Evaporation Duct Height Measurement Methods and Their Impact on Radar Propagation Estimates

DTIC Science & Technology

1998-03-01

AUTHOR John David Whalen 5. FUNDING NUMBERS 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) Naval Postgraduate School Monterey CA 93943...5000 PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME( S ) AND ADDRESS(ES) 10. SPONSORING/MONITORING AGENCY REPORT...impact the evaporation duct and its effect on the propagation of electromagnetic energy from the AEGIS AN/SPY-1 radars. Two ships, USS ANZIC and USS

Seventh Symposium on Subtypes of Musccarinic Receptors.

DTIC Science & Technology

1997-01-01

promises fewer and less severe side effects because of its favourable receptor profile and pharmacokinetic properties (2, 3). This compound has been...6). Following median laparotomy electromagnetic flow probes were positioned on one or both renal arteries. A cannula was introduced into a femoral...equipment for thermodilution and electromagnetic flow measurement (IFD, Miuhlheim, Germany) was used. Respiratory rate was evaluated from the C0 2

Transbronchial needle aspiration with a new electromagnetically-tracked TBNA needle

NASA Astrophysics Data System (ADS)

Choi, Jae; Popa, Teo; Gruionu, Lucian

2009-02-01

Transbronchial needle aspiration (TBNA) is a common method used to collect tissue for diagnosis of different chest diseases and for staging lung cancer, but the procedure has technical limitations. These limitations are mostly related to the difficulty of accurately placing the biopsy needles into the target mass. Currently, pulmonologists plan TBNA by examining a number of Computed Tomography (CT) scan slices before the operation. Then, they manipulate the bronchoscope down the respiratory track and blindly direct the biopsy. Thus, the biopsy success rate is low. The diagnostic yield of TBNA is approximately 70 percent. To enhance the accuracy of TBNA, we developed a TBNA needle with a tip position that can be electromagnetically tracked. The needle was used to estimate the bronchoscope's tip position and enable the creation of corresponding virtual bronchoscopic images from a preoperative CT scan. The TBNA needle was made with a flexible catheter embedding Wang Transbronchial Histology Needle and a sensor tracked by electromagnetic field generator. We used Aurora system for electromagnetic tracking. We also constructed an image-guided research prototype system incorporating the needle and providing a user-friendly interface to assist the pulmonologist in targeting lesions. To test the feasibility of the accuracy of the newly developed electromagnetically-tracked needle, a phantom study was conducted in the interventional suite at Georgetown University Hospital. Five TBNA simulations with a custom-made phantom with a bronchial tree were performed. The experimental results show that our device has potential to enhance the accuracy of TBNA.

Edge-filter technique and dominant frequency analysis for high-speed railway monitoring with fiber Bragg gratings

NASA Astrophysics Data System (ADS)

Kouroussis, Georges; Kinet, Damien; Mendoza, Edgar; Dupuy, Julien; Moeyaert, Véronique; Caucheteur, Christophe

2016-07-01

Structural health and operation monitoring are of growing interest in the development of railway networks. Conventional systems of infrastructure monitoring already exist (e.g. axle counters, track circuits) but present some drawbacks. Alternative solutions are therefore studied and developed. In this field, optical fiber sensors, and more particularly fiber Bragg grating (FBG) sensors, are particularly relevant due to their immunity to electromagnetic fields and simple wavelength-division-multiplexing capability. Field trials conducted up to now have demonstrated that FBG sensors provide useful information about train composition, positioning, speed, acceleration and weigh-in-motion estimations. Nevertheless, for practical deployment, cost-effectiveness should be ensured, specifically at the interrogator side that has also to be fast (>1 kHz repetition rate), accurate (∼1 pm wavelength shift) and reliable. To reach this objective, we propose in this paper to associate a low cost and high-speed interrogator coupled with an adequate signal-processing algorithm to dynamically monitor cascaded wavelength-multiplexed FBGs and to accurately capture the parameters of interest for railway traffic monitoring. This method has been field-tested with a Redondo Optics Inc. interrogator based on the well-known edge-filter demodulation technique. To determine the train speed from the raw data, a dominant frequency analysis has been implemented. Using this original method, we show that we can retrieve the speed of the trains, even when the time history strain signature is strongly affected by the measurement noise. The results are assessed by complimentary data obtained from a spectrometer-based FBG interrogator.

Comparison of Two Electromagnetic Navigation Systems For CT-Guided Punctures: A Phantom Study.

PubMed

Putzer, D; Arco, D; Schamberger, B; Schanda, F; Mahlknecht, J; Widmann, G; Schullian, P; Jaschke, W; Bale, R

2016-05-01

We compared the targeting accuracy and reliability of two different electromagnetic navigation systems for manually guided punctures in a phantom. CT data sets of a gelatin filled plexiglass phantom were acquired with 1, 3, and 5 mm slice thickness. After paired-point registration of the phantom, a total of 480 navigated stereotactic needle insertions were performed manually using electromagnetic guidance with two different navigation systems (Medtronic Stealth Station: AxiEM; Philips: PercuNav). A control CT was obtained to measure the target positioning error between the planned and actual needle trajectory. Using the Philips PercuNav, the accomplished Euclidean distances were 4.42 ± 1.33 mm, 4.26 ± 1.32 mm, and 4.46 ± 1.56 mm at a slice thickness of 1, 3, and 5 mm, respectively. The mean lateral positional errors were 3.84 ± 1.59 mm, 3.84 ± 1.43 mm, and 3.81 ± 1.71 mm, respectively. Using the Medtronic Stealth Station AxiEM, the Euclidean distances were 3.86 ± 2.28 mm, 3.74 ± 2.1 mm, and 4.81 ± 2.07 mm at a slice thickness of 1, 3, and 5 mm, respectively. The mean lateral positional errors were 3.29 ± 1.52 mm, 3.16 ± 1.52 mm, and 3.93 ± 1.68 mm, respectively. Both electromagnetic navigation devices showed excellent results regarding puncture accuracy in a phantom model. The Medtronic Stealth Station AxiEM provided more accurate results in comparison to the Philips PercuNav for CT with 3 mm slice thickness. One potential benefit of electromagnetic navigation devices is the absence of visual contact between the instrument and the sensor system. Due to possible interference with metal objects, incorrect position sensing may occur. In contrast to the phantom study, patient movement including respiration has to be compensated for in the clinical setting. • Commercially available electromagnetic navigation systems have the potential to improve the therapeutic range for CT guided percutaneous procedures by comparing the needle placement accuracy on the basis of planning CT data sets with different slice thickness. Citation Format: • Putzer D, Arco D, Schamberger B et al. Comparison of Two Electromagnetic Navigation Systems For CT-Guided Punctures: A Phantom Study. Fortschr Röntgenstr 2016; 188: 470 - 478. © Georg Thieme Verlag KG Stuttgart · New York.

Active magnetic bearings used as exciters for rolling element bearing outer race defect diagnosis.

PubMed

Xu, Yuanping; Di, Long; Zhou, Jin; Jin, Chaowu; Guo, Qintao

2016-03-01

The active health monitoring of rotordynamic systems in the presence of bearing outer race defect is considered in this paper. The shaft is assumed to be supported by conventional mechanical bearings and an active magnetic bearing (AMB) is used in the mid of the shaft location as an exciter to apply electromagnetic force to the system. We investigate a nonlinear bearing-pedestal system model with the outer race defect under the electromagnetic force. The nonlinear differential equations are integrated using the fourth-order Runge-Kutta algorithm. The simulation and experimental results show that the characteristic signal of outer race incipient defect is significantly amplified under the electromagnetic force through the AMBs, which is helpful to improve the diagnosis accuracy of rolling element bearing׳s incipient outer race defect. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Electromechanical millimotor

DOEpatents

Garcia, E.J.; Christenson, T.R.; Polosky, M.A.

1999-06-29

A millimeter-sized machine, including electromagnetic circuits adapted to convert electromagnetic energy to mechanical energy, for engaging and operating external mechanical loads. A plurality of millimeter-sized magnetic actuators operate out of phase with each other to control a plurality of millimeter-sized structural elements to drive an external mechanical load. Each actuator is connected to a link. Each link, in turn, is connected to a drive pinion at another similar pivoting joint. When the magnetic actuators are energized, each drive pinion is then capable of driving a larger output gear in gear-like fashion to produce positive torque about the drive pinion center at all angular positions of the output gear. 29 figs.

Electromechanical millimotor

DOEpatents

Garcia, Ernest J.; Christenson, Todd R.; Polosky, Marc A.

1999-01-01

A millimeter-sized machine, including electromagnetic circuits adapted to convert electromagnetic energy to mechanical energy, for engaging and operating external mechanical loads. A plurality of millimeter-sized magnetic actuators operate out of phase with each other to control a plurality of millimeter-sized structural elements to drive an external mechanical load. Each actuator is connected to a link. Each link, in turn, is connected to a drive pinion at another similar pivoting joint. When the magnetic actuators are energized, each drive pinion is then capable of driving a larger output gear in gear-like fashion to produce positive torque about the drive pinion center at all angular positions of the output gear.

Pedemis: a portable electromagnetic induction sensor with integrated positioning

NASA Astrophysics Data System (ADS)

Barrowes, Benjamin E.; Shubitidze, Fridon; Grzegorczyk, Tomasz M.; Fernández, Pablo; O'Neill, Kevin

2012-06-01

Pedemis (PortablE Decoupled Electromagnetic Induction Sensor) is a time-domain handheld electromagnetic induction (EMI) instrument with the intended purpose of improving the detection and classification of UneXploded Ordnance (UXO). Pedemis sports nine coplanar transmitters (the Tx assembly) and nine triaxial receivers held in a fixed geometry with respect to each other (the Rx assembly) but with that Rx assembly physically decoupled from the Tx assembly allowing flexible data acquisition modes and deployment options. The data acquisition (DAQ) electronics consists of the National Instruments (NI) cRIO platform which is much lighter and more energy efficient that prior DAQ platforms. Pedemis has successfully acquired initial data, and inversion of the data acquired during these initial tests has yielded satisfactory polarizabilities of a spherical target. In addition, precise positioning of the Rx assembly has been achieved via position inversion algorithms based solely on the data acquired from the receivers during the "on-time" of the primary field. Pedemis has been designed to be a flexible yet user friendly EMI instrument that can survey, detect and classify targets in a one pass solution. In this paper, the Pedemis instrument is introduced along with its operation protocols, initial data results, and current status.

Evaluating vehicular-induced bridge vibrations for energy harvesting applications

NASA Astrophysics Data System (ADS)

Reichenbach, Matthew; Fasl, Jeremiah; Samaras, Vasilis A.; Wood, Sharon; Helwig, Todd; Lindenberg, Richard

2012-04-01

Highway bridges are vital links in the transportation network in the United States. Identifying possible safety problems in the approximately 600,000 bridges across the country is generally accomplished through labor-intensive, visual inspections. Ongoing research sponsored by NIST seeks to improve inspection practices by providing real-time, continuous monitoring technology for steel bridges. A wireless sensor network with a service life of ten years that is powered by an integrated energy harvester is targeted. In order to achieve the target ten-year life for the monitoring system, novel approaches to energy harvesting for use in recharging batteries are investigated. Three main sources of energy are evaluated: (a) vibrational energy, (b) solar energy, and (c) wind energy. Assessing the energy produced from vehicular-induced vibrations and converted through electromagnetic induction is the focus of this paper. The goal of the study is to process acceleration data and analyze the vibrational response of steel bridges to moving truck loads. Through spectral analysis and harvester modeling, the feasibility of vibration-based energy harvesting for longterm monitoring can be assessed. The effects of bridge conditions, ambient temperature, truck traffic patterns, and harvester position on the power content of the vibrations are investigated. With sensor nodes continually recharged, the proposed real-time monitoring system will operate off the power grid, thus reducing life cycle costs and enhancing inspection practices for state DOTs. This paper will present the results of estimating the vibration energy of a steel bridge in Texas.

The effects of the photomask on multiphase shift test monitors

NASA Astrophysics Data System (ADS)

McIntyre, Gregory; Neureuther, Andrew

2006-10-01

A series of chromeless multiple-phase shift lithographic test monitors have been previously introduced. This paper investigates various effects that impact the performance of these monitors, focusing primarily on PSM Polarimetry, a technique to monitor illumination polarization. The measurement sensitivities from a variety of scalar and rigorous electromagnetic simulations are compared to experimental results from three industrial quality multi-phase test reticles. This analysis enables the relative importance of the various effects to be identified and offers the industry unique insight into various issues associated with the photomask. First, the unavoidable electromagnetic interaction as light propagates through the multiple phase steps of the mask topography appears to account for about 10 to 20% of the lost sensitivity, when experimental results are compared to an ideal simulated case. The polarization dependence of this effect is analyzed, concluding that the 4-phase topography is more effective at manipulating TM polarization. Second, various difficulties in the fabrication of these complicated mask patterns are described and likely account for an additional 60-80% loss in sensitivity. Smaller effects are also described, associated with the photoresist, mask design and subtle differences in the proximity effect of TE and TM polarization of off-axis light at high numerical aperture. Finally, the question: "How practical is PSM polarimetry?" is considered. It is concluded that, despite many severe limiting factors, an accurately calibrated test reticle promises to monitor polarization in state-of-the-art lithography scanners to within about 2%.

Optical Sensors for Monitoring Gamma and Neutron Radiation

NASA Technical Reports Server (NTRS)

Boyd, Clark D.

2011-01-01

For safety and efficiency, nuclear reactors must be carefully monitored to provide feedback that enables the fission rate to be held at a constant target level via adjustments in the position of neutron-absorbing rods and moderating coolant flow rates. For automated reactor control, the monitoring system should provide calibrated analog or digital output. The sensors must survive and produce reliable output with minimal drift for at least one to two years, for replacement only during refueling. Small sensor size is preferred to enable more sensors to be placed in the core for more detailed characterization of the local fission rate and fuel consumption, since local deviations from the norm tend to amplify themselves. Currently, reactors are monitored by local power range meters (LPRMs) based on the neutron flux or gamma thermometers based on the gamma flux. LPRMs tend to be bulky, while gamma thermometers are subject to unwanted drift. Both electronic reactor sensors are plagued by electrical noise induced by ionizing radiation near the reactor core. A fiber optic sensor system was developed that is capable of tracking thermal neutron fluence and gamma flux in order to monitor nuclear reactor fission rates. The system provides near-real-time feedback from small- profile probes that are not sensitive to electromagnetic noise. The key novel feature is the practical design of fiber optic radiation sensors. The use of an actinoid element to monitor neutron flux in fiber optic EFPI (extrinsic Fabry-Perot interferometric) sensors is a new use of material. The materials and structure used in the sensor construction can be adjusted to result in a sensor that is sensitive to just thermal, gamma, or neutron stimulus, or any combination of the three. The tested design showed low sensitivity to thermal and gamma stimuli and high sensitivity to neutrons, with a fast response time.

Detection of contaminant plumes by bore­ hole geophysical logging

USGS Publications Warehouse

Mack, Thomas J.

1993-01-01

Two borehole geophysical methods—electromagnetic induction and natural gamma radiation logs—were used to vertically delineate landfill leachate plumes in a glacial aquifer. Geophysical logs of monitoring wells near two land-fills in a glacial aquifer in west-central Vermont show that borehole geophysical methods can aid in interpretation of geologic logs and placement of monitoring well screens to sample landfill leachate plumes.Zones of high electrical conductance were delineated from the electromagnetic log in wells near two landfills. Some of these zones were found to correlate with silt and clay units on the basis of drilling and gamma logs. Monitoring wells were screened specifically in zones of high electrical conductivity that did not correlate to a silt or clay unit. Zones of high electrical conductivity that did not correlate to a silt or clay unit were caused by the presence of ground water with a high specific conductance, generally from 1000 to 2370 μS/cm (microsiemens per centimeter at 25 degrees Celsius). Ambient ground water in the study area has a specific conductance of approximately 200 to 400 μS/cm. Landfill leachate plumes were found to be approximately 5 to 20 feet thick and to be near the water table surface.

Tracing Acetylene Dissolved in Transformer Oil by Tunable Diode Laser Absorption Spectrum.

PubMed

Ma, Guo-Ming; Zhao, Shu-Jing; Jiang, Jun; Song, Hong-Tu; Li, Cheng-Rong; Luo, Ying-Ting; Wu, Hao

2017-11-02

Dissolved gas analysis (DGA) is widely used in monitoring and diagnosing of power transformer, since the insulation material in the power transformer decomposes gases under abnormal operation condition. Among the gases, acetylene, as a symbol of low energy spark discharge and high energy electrical faults (arc discharge) of power transformer, is an important monitoring parameter. The current gas detection method used by the online DGA equipment suffers from problems such as cross sensitivity, electromagnetic compatibility and reliability. In this paper, an optical gas detection system based on TDLAS technology is proposed to detect acetylene dissolved in transformer oil. We selected a 1530.370 nm laser in the near infrared wavelength range to correspond to the absorption peak of acetylene, while using the wavelength modulation strategy and Herriott cell to improve the detection precision. Results show that the limit of detection reaches 0.49 ppm. The detection system responds quickly to changes of gas concentration and is easily to maintenance while has no electromagnetic interference, cross-sensitivity, or carrier gas. In addition, a complete detection process of the system takes only 8 minutes, implying a practical prospect of online monitoring technology.

Electromagnetic wave energy converter

NASA Technical Reports Server (NTRS)

Bailey, R. L. (Inventor)

1973-01-01

Electromagnetic wave energy is converted into electric power with an array of mutually insulated electromagnetic wave absorber elements each responsive to an electric field component of the wave as it impinges thereon. Each element includes a portion tapered in the direction of wave propagation to provide a relatively wideband response spectrum. Each element includes an output for deriving a voltage replica of the electric field variations intercepted by it. Adjacent elements are positioned relative to each other so that an electric field subsists between adjacent elements in response to the impinging wave. The electric field results in a voltage difference between adjacent elements that is fed to a rectifier to derive dc output power.

Open-loop characteristics of magnetic suspension systems using electromagnets mounted in a planar array

NASA Technical Reports Server (NTRS)

Groom, Nelson J.; Britcher, Colin P.

1992-01-01

The open-loop characteristics of a Large-Gap Magnetic Suspension System (LGMSS) were studied and numerical results are presented. The LGMSS considered provides five-degree-of-freedom control. The suspended element is a cylinder that contains a core composed of permanent magnet material. The magnetic actuators are air core electromagnets mounted in a planar array. Configurations utilizing five, six, seven, and eight electromagnets were investigated and all configurations were found to be controllable from coil currents and observable from suspended element positions. Results indicate that increasing the number of coils has an insignificant effect on mode shapes and frequencies.

Electromagnetic interference with pacemakers caused by portable media players.

PubMed

Thaker, Jay P; Patel, Mehul B; Jongnarangsin, Krit; Liepa, Valdis V; Thakur, Ranjan K

2008-04-01

Electromagnetic fields generated by electrical devices may cause interference with permanent pacemakers. Media players are becoming a common mode of portable entertainment. The most common media players used worldwide are iPods. These devices are often carried in a shirt chest pocket, which may place the devices close to an implanted pacemaker. The purpose of this study was to determine if iPods cause interference with pacemakers. In this prospective, single-blinded study, 100 patients who had cardiac pacemakers were tested with four types of iPods to assess for interference. Patients were monitored by a single-channel ECG monitor as well as the respective pacemaker programmer via the telemetry wand. iPods were tested by placing them 2 inches anterior to the pacemaker and wand for up to 10 seconds. To simulate actual use, standard-issue headphones were plugged into the iPods. To maintain consistency, the volume was turned up maximally, and the equalizer was turned off. A subset of 25 patients underwent testing on 2 separate days to assess for reproducibility of interference. Pacemaker interference was categorized as type I or type II telemetry interference. Type I interference was associated with atrial and/or ventricular high rates on rate histograms. Type II interference did not affect pacemaker rate counters. Electromagnetic emissions from the four iPods also were evaluated in a Faraday cage to determine the mechanism of the observed interference. One hundred patients (63 men and 37 women; mean age 77.1 +/- 7.6 years) with 11 single-chamber pacemakers and 89 dual-chamber pacemakers underwent 800 tests. The incidence of any type of interference was 51% of patients and 20% of tests. Type I interference was seen in 19% of patients and type II in 32% of patients. Reproducibility testing confirmed that interference occurred regardless of pacing configuration (unipolar or bipolar), pacing mode (AAI, VVI, or DDD), and from one day to the next. Electromagnetic emissions testing from the iPods demonstrated maximum emissions in the pacemaker carrier frequency range when the iPod was turned "on" with the headphones attached. iPods placed within 2 inches of implanted pacemakers monitored via the telemetry wand can cause interference with pacemakers.

Physics of giant electromagnetic pulse generation in short-pulse laser experiments.

PubMed

Poyé, A; Hulin, S; Bailly-Grandvaux, M; Dubois, J-L; Ribolzi, J; Raffestin, D; Bardon, M; Lubrano-Lavaderci, F; D'Humières, E; Santos, J J; Nicolaï, Ph; Tikhonchuk, V

2015-04-01

In this paper we describe the physical processes that lead to the generation of giant electromagnetic pulses (GEMPs) at powerful laser facilities. Our study is based on experimental measurements of both the charging of a solid target irradiated by an ultra-short, ultra-intense laser and the detection of the electromagnetic emission in the GHz domain. An unambiguous correlation between the neutralization current in the target holder and the electromagnetic emission shows that the source of the GEMP is the remaining positive charge inside the target after the escape of fast electrons accelerated by the ultra-intense laser. A simple model for calculating this charge in the thick target case is presented. From this model and knowing the geometry of the target holder, it becomes possible to estimate the intensity and the dominant frequencies of the GEMP at any facility.

Generalized Case ``Van Kampen theory for electromagnetic oscillations in a magnetized plasma

NASA Astrophysics Data System (ADS)

Bairaktaris, F.; Hizanidis, K.; Ram, A. K.

2017-10-01

The Case-Van Kampen theory is set up to describe electrostatic oscillations in an unmagnetized plasma. Our generalization to electromagnetic oscillations in magnetized plasma is formulated in the relativistic position-momentum phase space of the particles. The relativistic Vlasov equation includes the ambient, homogeneous, magnetic field, and space-time dependent electromagnetic fields that satisfy Maxwell's equations. The standard linearization technique leads to an equation for the perturbed distribution function in terms of the electromagnetic fields. The eigenvalues and eigenfunctions are obtained from three integrals `` each integral being over two different components of the momentum vector. Results connecting phase velocity, frequency, and wave vector will be presented. Supported in part by the Hellenic National Programme on Controlled Thermonuclear Fusion associated with the EUROfusion Consortium, and by DoE Grant DE-FG02-91ER-54109.

On the use of particle filters for electromagnetic tracking in high dose rate brachytherapy.

PubMed

Götz, Th I; Lahmer, G; Brandt, T; Kallis, K; Strnad, V; Bert, Ch; Hensel, B; Tomé, A M; Lang, E W

2017-09-12

Modern radiotherapy of female breast cancers often employs high dose rate brachytherapy, where a radioactive source is moved inside catheters, implanted in the female breast, according to a prescribed treatment plan. Source localization relative to the patient's anatomy is determined with solenoid sensors whose spatial positions are measured with an electromagnetic tracking system. Precise sensor dwell position determination is of utmost importance to assure irradiation of the cancerous tissue according to the treatment plan. We present a hybrid data analysis system which combines multi-dimensional scaling with particle filters to precisely determine sensor dwell positions in the catheters during subsequent radiation treatment sessions. Both techniques are complemented with empirical mode decomposition for the removal of superimposed breathing artifacts. We show that the hybrid model robustly and reliably determines the spatial positions of all catheters used during the treatment and precisely determines any deviations of actual sensor dwell positions from the treatment plan. The hybrid system only relies on sensor positions measured with an EMT system and relates them to the spatial positions of the implanted catheters as initially determined with a computed x-ray tomography.

Tethered satellite system control using electromagnetic forces and reaction wheels

NASA Astrophysics Data System (ADS)

Alandi Hallaj, Mohammad Amin; Assadian, Nima

2015-12-01

In this paper a novel non-rotating space tethered configuration is introduced which its relative positions controlled using electromagnetic forces. The attitude dynamics is controlled by three reaction wheels in the body axes. The nonlinear coupled orbital dynamics of a dumbbell tethered satellite formation flight are derived through a constrained Lagrangian approach. These equations are presented in the leader satellite orbital frame. The tether is assumed to be mass-less and straight, and the J2 perturbation is included to the analysis. The forces and the moments of the electromagnetic coils are modeled based on the far-filed model of the magnetic dipoles. A guidance scheme for generating the desired positions as a function of time in Cartesian form is presented. The satellite tethered formation with variable length is controlled utilizing a linear controller. This approach is applied to a specified scenario and it is shown that the nonlinear guidance method and the linear controller can control the nonlinear system of the tethered formation and the results are compared with optimal control approach.

Electromagnetic navigated positioning of the maxilla after Le Fort I osteotomy in preclinical orthognathic surgery cases.

PubMed

Berger, Moritz; Nova, Igor; Kallus, Sebastian; Ristow, Oliver; Eisenmann, Urs; Freudlsperger, Christian; Seeberger, Robin; Hoffmann, Jürgen; Dickhaus, Hartmut

2017-03-01

Inaccuracies in orthognathic surgery can be caused during face-bow registration, model surgery on plaster models, and intermaxillary splint manufacturing. Electromagnetic (EM) navigation is a promising method for splintless digitized maxillary positioning. After performing Le Fort I osteotomy on 10 plastic skulls, the target position of the maxilla was guided by an EM navigation system. Specially implemented software illustrated the target position by real-time multistage colored three-dimensional imaging. Accuracy was determined by using pre- and postoperative cone beam computed tomography. The high accuracy of the EM system was underlined by the fact that it had a navigated maxilla position discrepancy of only 0.4 mm, which was verified by postoperative cone beam computed tomography. This preclinical study demonstrates a precise digitized approach for splintless maxillary repositioning after Le Fort I osteotomy. The accuracy and intuitive illustration of the introduced EM navigation system is promising for potential daily use in orthognathic surgery. Copyright © 2016 Elsevier Inc. All rights reserved.

Subsurface Electromagnetic Induction Imaging for Unexploded Ordnance Detection

DTIC Science & Technology

2012-01-01

Baum, 1999; Pasion and Oldenburg, 2001). The EMI- response problem has been solved analytically for spheroids (Ao et al., 2002; Barrowes et al., 2004...components. We also have made explicit the fact that the polarizabilities are always positive ( Pasion et al., 2008); we impose this constraint in the...Wiley-Blackwell, Chichester, UK. Pasion , L.R., Oldenburg, D.W., 2001. A discrimination algorithm for UXO using time- domain electromagnetic induction

Regulation of Electromagnetic Radiation: A Confusing Course through Modulating E and H Waves.

DTIC Science & Technology

1982-02-15

29 Biological Effects of RFR: Clinical Findings ......... 30 Cataract ........... . o . o ....... o 30 Psychological Effects...Claims Act alleges injuries to a contractor employee conducting tests of potential effects of electromagnetic pulse radiation on a Minuteman missile site...absorption is the position of the receiving object (e.g. human being, animal or simulated model test subject) relative to the E, H or K planes (K is a

The ATLAS Liquid Argon Electromagnetic Calorimeter

NASA Astrophysics Data System (ADS)

Carminati, L.

2005-10-01

The construction of the ATLAS Liquid Argon Electromagnetic calorimeter has been completed and commissioning is in progress. After a brief description of the detector layout, readout electronics and calibration, a review of the present status of the integration and the detector qualification is reported. Finally a selection of performance results obtained during several test beams will be presented with particular attention to linearity, uniformity, position reconstruction and γ/π0 separation.

Lie algebraic approach to the time-dependent quantum general harmonic oscillator and the bi-dimensional charged particle in time-dependent electromagnetic fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ibarra-Sierra, V.G.; Sandoval-Santana, J.C.; Cardoso, J.L.

We discuss the one-dimensional, time-dependent general quadratic Hamiltonian and the bi-dimensional charged particle in time-dependent electromagnetic fields through the Lie algebraic approach. Such method consists in finding a set of generators that form a closed Lie algebra in terms of which it is possible to express a quantum Hamiltonian and therefore the evolution operator. The evolution operator is then the starting point to obtain the propagator as well as the explicit form of the Heisenberg picture position and momentum operators. First, the set of generators forming a closed Lie algebra is identified for the general quadratic Hamiltonian. This algebra ismore » later extended to study the Hamiltonian of a charged particle in electromagnetic fields exploiting the similarities between the terms of these two Hamiltonians. These results are applied to the solution of five different examples: the linear potential which is used to introduce the Lie algebraic method, a radio frequency ion trap, a Kanai–Caldirola-like forced harmonic oscillator, a charged particle in a time dependent magnetic field, and a charged particle in constant magnetic field and oscillating electric field. In particular we present exact analytical expressions that are fitting for the study of a rotating quadrupole field ion trap and magneto-transport in two-dimensional semiconductor heterostructures illuminated by microwave radiation. In these examples we show that this powerful method is suitable to treat quadratic Hamiltonians with time dependent coefficients quite efficiently yielding closed analytical expressions for the propagator and the Heisenberg picture position and momentum operators. -- Highlights: •We deal with the general quadratic Hamiltonian and a particle in electromagnetic fields. •The evolution operator is worked out through the Lie algebraic approach. •We also obtain the propagator and Heisenberg picture position and momentum operators. •Analytical expressions for a rotating quadrupole field ion trap are presented. •Exact solutions for magneto-transport in variable electromagnetic fields are shown.« less

Documentation for a web site to serve ULF-EM (Ultra-Low Frequency Electromagnetic) data to the public

USGS Publications Warehouse

Neumann, Danny A.; McPherson, Selwyn; Klemperer, Simon L.; Glen, Jonathan M.G.; McPhee, Darcy K.; Kappler, Karl

2011-01-01

The Stanford Ultra-Low Frequency Electromagnetic (ULF-EM) Monitoring Project is recording naturally varying electromagnetic signals adjacent to active earthquake faults, in an attempt to establish whether there is any variation in these signals associated with earthquakes. Our project is collaborative between Stanford University, the U.S. Geological Survey (USGS), and UC Berkeley. Lead scientists are Simon Klemperer (Stanford University), Jonathan Glen (USGS) and Darcy Karakelian McPhee (USGS). Our initial sites are in the San Francisco Bay Area, monitoring different strands of the San Andreas fault system, at Stanford University's Jasper Ridge Biological Preserve (JRSC), Marin Headlands of the Golden Gate National Recreation Area (MHDL), and the UC Berkeley's Russell Reservation Field Station adjacent to Briones Regional Park (BRIB). In addition, we maintain in conjunction with the Berkeley Seismological Laboratory (BSL) two remote reference stations at the Bear Valley Ranch in Parkfield, Calif., (PKD) and the San Andreas Geophysical Observatory at Hollister, Calif., (SAO). Metadata about our site can be found at http://ulfem-data.stanford.edu/info.html. Site descriptions can be found at the BSL at http://seismo.berkeley.edu/, and seismic data can be obtained from the Northern California Earthquake Data Center at http://www.ncedc.org/. The site http://ulfem-data.stanford.edu/ allows access to data from the Stanford-USGS sites JRSC, MHDL and BRIB, as well as UC Berkeley sites PKD and SAO.

Application and evaluation of electromagnetic methods for imaging saltwater intrusion in coastal aquifers: Seaside Groundwater Basin, California

USGS Publications Warehouse

Nenna, Vanessa; Herckenrather, Daan; Knight, Rosemary; Odlum, Nick; McPhee, Darcy

2013-01-01

Developing effective resource management strategies to limit or prevent saltwater intrusion as a result of increasing demands on coastal groundwater resources requires reliable information about the geologic structure and hydrologic state of an aquifer system. A common strategy for acquiring such information is to drill sentinel wells near the coast to monitor changes in water salinity with time. However, installation and operation of sentinel wells is costly and provides limited spatial coverage. We studied the use of noninvasive electromagnetic (EM) geophysical methods as an alternative to installation of monitoring wells for characterizing coastal aquifers. We tested the feasibility of using EM methods at a field site in northern California to identify the potential for and/or presence of hydraulic communication between an unconfined saline aquifer and a confined freshwater aquifer. One-dimensional soundings were acquired using the time-domain electromagnetic (TDEM) and audiomagnetotelluric (AMT) methods. We compared inverted resistivity models of TDEM and AMT data obtained from several inversion algorithms. We found that multiple interpretations of inverted models can be supported by the same data set, but that there were consistencies between all data sets and inversion algorithms. Results from all collected data sets suggested that EM methods are capable of reliably identifying a saltwater-saturated zone in the unconfined aquifer. Geophysical data indicated that the impermeable clay between aquifers may be more continuous than is supported by current models.

Assessment of Electromagnetic and Passive Diffuse Infrared Sensors in Detection of IED-Related Behavior

DTIC Science & Technology

2008-06-01

sensors can accomplish complex monitoring tasks (Kaushik, Lovell , & Celler, 2007). There are additional problems with processing to track and detect...reported data frequently. Each mote uses two 1.5-volt alkaline AA batteries, and the mote’s lifespan is estimated at 250 hours 13th ICCRTS: C2 for... Lovell , & B. Celler. 2007, August. Evaluation of PIR detector characteristics for monitoring occupancy patterns for elderly people living alone at home

A Theoretical Model to Predict Both Horizontal Displacement and Vertical Displacement for Electromagnetic Induction-Based Deep Displacement Sensors

PubMed Central

Shentu, Nanying; Zhang, Hongjian; Li, Qing; Zhou, Hongliang; Tong, Renyuan; Li, Xiong

2012-01-01

Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type) to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA) to describe its sensing characters. However in many landslide and related geological engineering cases, both horizontal displacement and vertical displacement vary apparently and dynamically so both may require monitoring. In this study, a II-type deep displacement sensor is designed by revising our I-type sensor to simultaneously monitor the deep horizontal displacement and vertical displacement variations at different depths within a sliding mass. Meanwhile, a new theoretical modeling called the numerical integration-based equivalent loop approach (NIELA) has been proposed to quantitatively depict II-type sensors’ mutual inductance properties with respect to predicted horizontal displacements and vertical displacements. After detailed examinations and comparative studies between measured mutual inductance voltage, NIELA-based mutual inductance and EELA-based mutual inductance, NIELA has verified to be an effective and quite accurate analytic model for characterization of II-type sensors. The NIELA model is widely applicable for II-type sensors’ monitoring on all kinds of landslides and other related geohazards with satisfactory estimation accuracy and calculation efficiency. PMID:22368467

A theoretical model to predict both horizontal displacement and vertical displacement for electromagnetic induction-based deep displacement sensors.

PubMed

Shentu, Nanying; Zhang, Hongjian; Li, Qing; Zhou, Hongliang; Tong, Renyuan; Li, Xiong

2012-01-01

Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type) to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA) to describe its sensing characters. However in many landslide and related geological engineering cases, both horizontal displacement and vertical displacement vary apparently and dynamically so both may require monitoring. In this study, a II-type deep displacement sensor is designed by revising our I-type sensor to simultaneously monitor the deep horizontal displacement and vertical displacement variations at different depths within a sliding mass. Meanwhile, a new theoretical modeling called the numerical integration-based equivalent loop approach (NIELA) has been proposed to quantitatively depict II-type sensors' mutual inductance properties with respect to predicted horizontal displacements and vertical displacements. After detailed examinations and comparative studies between measured mutual inductance voltage, NIELA-based mutual inductance and EELA-based mutual inductance, NIELA has verified to be an effective and quite accurate analytic model for characterization of II-type sensors. The NIELA model is widely applicable for II-type sensors' monitoring on all kinds of landslides and other related geohazards with satisfactory estimation accuracy and calculation efficiency.

Eddy-Current Monitoring Of Composite Layups

NASA Technical Reports Server (NTRS)

Fox, Robert L.; Buckley, John D.

1993-01-01

Eddy-current-probe apparatus used to determine predominant orientations of fibers in fiber/matrix composite materials. Apparatus nondestructive, noninvasive means for monitoring composite prepregs and layups during fabrication to ensure predictable and repeatable mechanical properties of finished composite panels. Consists essentially of electromagnet coil wrapped around horseshoe-shaped powdered-iron or ferrite ore. Optionally, capacitor included in series or parallel with coil to form resonant circuit. Impedance monitor excites radio-frequency current in coil and measures impedance of probe circuit. Affected by whatever material placed near ends of core, where material intercepts alternating magnetic field excited in core by current in coil.

Simplified spatiotemporal electromagnetic induction - salinity multi-field calibration

USDA-ARS?s Scientific Manuscript database

Salinity-affected farmlands are common in arid and semi-arid regions. To assure long-term sustainability of farming practices in these areas, soil salinity (ECe) should be routinely mapped and monitored. Salinity can be measured through soil sampling directed by geospatial measurements of apparent s...

Geophysical Observatory in Kamchatka region for monitoring of phenomena connected with seismic activity

NASA Astrophysics Data System (ADS)

Uyeda, S.; Nagao, T.; Hattori, K.; Hayakawa, M.; Miyaki, K.; Molchanov, O.; Gladychev, V.; Baransky, L.; Chtchekotov, A.; Fedorov, E.; Pokhotelov, O.; Andreevsky, S.; Rozhnoi, A.; Khabazin, Y.; Gorbatikov, A.; Gordeev, E.; Chebrov, V.; Sinitzin, V.; Lutikov, A.; Yunga, S.; Kosarev, G.; Surkov, V.; Belyaev, G.

Regular monitoring of some geophysical parameters in association with seismicity has been carried out since last year at the Japan-Russian Complex Geophysical Observatory in the Kamchatka region. This observatory was organized in connection with the ISTC project in Russia and was motivated by the results of the FRONTIER/RIKEN and FRONTIER/NASDA research projects in Japan. The main purpose of the observations is to investigate the electromagnetic and acoustic phenomena induced by the lithosphere processes (especially by seismic activity). The seismicity of the Kamchatka area is analyzed and a description of the observatory equipment is presented. At present, the activity of the observatory includes the seismic (frequency range ∆F = 0.5 - 40 Hz) and meteorological recordings, together with seismo-acoustic (∆F = 30 - 1000 Hz) and electromagnetic observations: three-component magnetic ULF variations ( ∆F = 0.003 - 30 Hz), three-component electric potential variations ( ∆F < 1.0 Hz), and VLF transmitter's signal perturbations ( ∆F ~ 10 - 40 kHz).

The First Unambiguous Electromagnetic Counterpart to a Gravitational-Wave Signal: GRB 170817A and GW170817

NASA Astrophysics Data System (ADS)

Goldstein, Adam

2018-01-01

On 2017 August 17 at 12:41:06 UTC the Fermi Gamma-ray Burst Monitor (GBM) detected and triggered on the short gamma-ray burst (GRB) 170817A. Approximately 2 s prior to this GRB, the LIGO gravitational-wave observatory triggered on a binary compact merger candidate associated with the GRB. This is the first unambiguous coincident observation of gravitational waves and electromagnetic radiation from a single astrophysical source and marks the start of gravitational-wave multi-messenger astronomy. We report the GBM observations and analysis of this short GRB and the joint science that results from this discovery.

Electromagnetic wave method for mapping subterranean earth formations

DOEpatents

Shuck, Lowell Z.; Fasching, George E.; Balanis, Constantine A.

1977-01-01

The present invention is directed to a method for remotely mapping subterranean coal beds prior to and during in situ gasification operations. This method is achieved by emplacing highly directional electromagnetic wave transmitters and receivers in bore holes penetrating the coal beds and then mapping the anomalies surrounding each bore hole by selectively rotating and vertically displacing the directional transmitter in a transmitting mode within the bore hole, and thereafter, initiating the gasification of the coal at bore holes separate from those containing the transmitters and receivers and then utilizing the latter for monitoring the burn front as it progresses toward the transmitters and receivers.

A NOVEL TECHNIQUE APPLYING SPECTRAL ESTIMATION TO JOHNSON NOISE THERMOMETRY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ezell, N Dianne Bull; Britton Jr, Charles L; Roberts, Michael

Johnson noise thermometry (JNT) is one of many important measurements used to monitor the safety levels and stability in a nuclear reactor. However, this measurement is very dependent on the electromagnetic environment. Properly removing unwanted electromagnetic interference (EMI) is critical for accurate drift free temperature measurements. The two techniques developed by Oak Ridge National Laboratory (ORNL) to remove transient and periodic EMI are briefly discussed in this document. Spectral estimation is a key component in the signal processing algorithm utilized for EMI removal and temperature calculation. Applying these techniques requires the simple addition of the electronics and signal processing tomore » existing resistive thermometers.« less

Interpretation of Blazar Flux Variations as Music

NASA Astrophysics Data System (ADS)

Webb, J. R.

2003-12-01

Blazars are believed to be distant galaxies in the process of formation. They emit electromagnetic radiation (light) over the entire electromagnetic spectrum from radio waves to gamma-rays. The emission varies with time in most frequency ranges and the causes for the variation are yet to be adequately explained. Astronomers have been monitoring these objects with optical telescopes for over 50 years now and we have collected a large database of brightnesses over these fifty years. This paper presents some of these light curves, and adopts a computational method to translate the brightness fluctuations into musical tones. These tones are then converted to sound using a midi synthesizer on a PC.

Plasmon-Enhanced Optical Sensors: A Review

PubMed Central

Li, Ming; Cushing, Scott K

2014-01-01

Surface plasmon resonance (SPR) has found extensive applications in chemi-sensors and biosensors. Plasmons play different roles in different types of optical sensors. SPR transduces a signal in a colorimetric sensor through shifts in the spectral position and intensity in response to external stimuli. SPR can also concentrate the incident electromagnetic field in a nanostructure, modulating fluorescence emission and enabling plasmon-enhanced fluorescence to be used for ultrasensitive detection. Furthermore, plasmons have been extensively used for amplifying a Raman signal in a surface-enhanced Raman scattering sensor. This paper presents a review of recent research progress in plasmon-enhanced optical sensing, giving an emphasis on the physical basis of plasmon-enhanced sensors and how these principles guide the design of sensors. In particular, this paper discusses the design strategies for nanomaterials and nanostructures to plasmonically enhance optical sensing signals, also highlighting the applications of plasmon-enhanced optical sensors in health care, homeland security, food safety and environmental monitoring. PMID:25365823

Characterization of the Goubau line for testing beam diagnostic instruments

NASA Astrophysics Data System (ADS)

Kim, S. Y.; Stulle, F.; Sung, C. K.; Yoo, K. H.; Seok, J.; Moon, K. J.; Choi, C. U.; Chung, Y.; Kim, G.; Woo, H. J.; Kwon, J.; Lee, I. G.; Choi, E. M.; Chung, M.

2017-12-01

One of the main characteristics of the Goubau line is that it supports a low-loss, non-radiated surface wave guided by a dielectric-coated metal wire. The dominant mode of the surface wave along the Goubau line is a TM01 mode, which resembles the pattern of the electromagnetic fields induced in the metallic beam pipe when the charged particle beam passes through it. Therefore, the Goubau line can be used for the preliminary bench test and performance optimization of the beam diagnostic instruments without requiring charged particle beams from the accelerators. In this paper, we discuss the basic properties of the Goubau line for testing beam diagnostic instruments and present the initial test results for button-type beam position monitors (BPMs). The experimental results are consistent with the theoretical estimations, which indicates that Goubau line allows effective testing of beam diagnostic equipment.

Vertical-deformation, water-level, microgravity, geodetic, water-chemistry, and flow-rate data collected during injection, storage, and recovery tests at Lancaster, Antelope Valley, California, September 1995 through September 1998

USGS Publications Warehouse

Metzger, Loren F.; Ikehara, Marti E.; Howle, James F.

2001-01-01

A series of freshwater injection, storage, and recovery tests were conducted from September 1995 through September 1998 to evaluate the feasibility of artificially recharging ground water in the Lancaster area of the Antelope Valley, California. The tests used two production wells at a well field located in the southern part of the city of Lancaster. Monitoring networks were established at or in the vicinity of the test site to measure vertical deformation of the aquifer system, water-level fluctuations, land-surface deformation, water chemistry, and injection well flow rates during water injection and recovery. Data presented in this report were collected from a dual extensometer; 10 piezometers; 1 barometer; 27 active or abandoned production wells; 31 gravity stations; 124 bench marks; 1 permanent and 1 temporary continuous Global Positioning System (GPS) station; 3 tiltmeters; and 2 electromagnetic flowmeters from September 1995 through September 1998. This report discusses the location and design of the monitoring networks and the methods used to collect and process the data, and presents the data in tables and graphs.

The combined action of a passive exoskeleton and an EMG-controlled neuroprosthesis for upper limb stroke rehabilitation: First results of the RETRAINER project.

PubMed

Ambrosini, E; Ferrante, S; Zajc, J; Bulgheroni, M; Baccinelli, W; d'Amico, E; Schauer, T; Wiesener, C; Russold, M; Gfoehler, M; Puchinger, M; Weber, M; Becker, S; Krakow, K; Rossini, M; Proserpio, D; Gasperini, G; Molteni, F; Ferrigno, G; Pedrocchi, A

2017-07-01

The combined use of Functional Electrical Stimulation (FES) and robotic technologies is advocated to improve rehabilitation outcomes after stroke. This work describes an arm rehabilitation system developed within the European project RETRAINER. The system consists of a passive 4-degrees-of-freedom exoskeleton equipped with springs to provide gravity compensation and electromagnetic brakes to hold target positions. FES is integrated in the system to provide additional support to the most impaired muscles. FES is triggered based on the volitional EMG signal of the same stimulated muscle; in order to encourage the active involvement of the patient the volitional EMG is also monitored throughout the task execution and based on it a happy or sad emoji is visualized at the end of each task. The control interface control of the system provides a GUI and multiple software tools to organize rehabilitation exercises and monitor rehabilitation progress. The functionality and the usability of the system was evaluated on four stroke patients. All patients were able to use the system and judged positively its wearability and the provided support. They were able to trigger the stimulation based on their residual muscle activity and provided different levels of active involvement in the exercise, in agreement with their level of impairment. A randomized controlled trial aimed at evaluating the effectiveness of the RETRAINER system to improve arm function after stroke is currently ongoing.

Improved Rotary Transformer For Shaft-Position Indicator

NASA Technical Reports Server (NTRS)

Mclyman, W. T.

1991-01-01

Improved rotary transformer for Inductosyn (or equivalent) shaft-position-indicating circuit has pair of ferrite cores instead of the solid-iron cores. Designed with view toward decreasing excitation power (to maximum allowable 2 W) supplied to shaft-position-indicating circuit to increase its output signal and make tracking system less vulnerable to electromagnetic interference.

Apparatus for processing electromagnetic radiation and method

NASA Technical Reports Server (NTRS)

Gatewood, George D. (Inventor)

1983-01-01

Measuring apparatus including a ruled member having alternate transparent and opaque zones. An optical coupler connecting the ruled member with electromagnetic radiation-conversion apparatus. The conversion apparatus may include a photomultiplier and a discriminator. Radiation impinging on the ruled member will, in part, be converted to electrical pulses which correspond to the intensity of the radiation. A method of processing electromagnetic radiation includes providing a member having alternating dark and light zones, establishing movement of the member through the beam of electromagnetic radiation with the dark zones interrupting passage of radiation through the rule, providing an optical coupler to connect a portion of the radiation with a conversion station where the radiation portion is converted into an electrical pulse which is related to the intensity of the radiation received at the conversion station. The electrical pulses may be counted and the digitized signals stored or permanently recorded to produce positional information.

Gold Sample Heating within the TEMPUS Electromagnetic Levitation Furnace

NASA Technical Reports Server (NTRS)

2003-01-01

A gold sample is heated by the TEMPUS electromagnetic levitation furnace on STS-94, 1997, MET:10/09:20 (approximate). The sequence shows the sample being positioned electromagnetically and starting to be heated to melting. TEMPUS (stands for Tiegelfreies Elektromagnetisches Prozessiere unter Schwerelosigkeit (containerless electromagnetic processing under weightlessness). It was developed by the German Space Agency (DARA) for flight aboard Spacelab. The DARA project scientist was Igon Egry. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1R mission (STS-94, July 1-17 1997). DARA and NASA are exploring the possibility of flying an advanced version of TEMPUS on the International Space Station. (460KB, 14-second MPEG, screen 160 x 120 pixels; downlinked video, higher quality not available) A still JPG composite of this movie is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300190.html.

Method for imaging with low frequency electromagnetic fields

DOEpatents

Lee, Ki H.; Xie, Gan Q.

1994-01-01

A method for imaging with low frequency electromagnetic fields, and for interpreting the electromagnetic data using ray tomography, in order to determine the earth conductivity with high accuracy and resolution. The imaging method includes the steps of placing one or more transmitters, at various positions in a plurality of transmitter holes, and placing a plurality of receivers in a plurality of receiver holes. The transmitters generate electromagnetic signals which diffuse through a medium, such as earth, toward the receivers. The measured diffusion field data H is then transformed into wavefield data U. The traveltimes corresponding to the wavefield data U, are then obtained, by charting the wavefield data U, using a different regularization parameter .alpha. for each transform. The desired property of the medium, such as conductivity, is then derived from the velocity, which in turn is constructed from the wavefield data U using ray tomography.

Method for imaging with low frequency electromagnetic fields

DOEpatents

Lee, K.H.; Xie, G.Q.

1994-12-13

A method is described for imaging with low frequency electromagnetic fields, and for interpreting the electromagnetic data using ray tomography, in order to determine the earth conductivity with high accuracy and resolution. The imaging method includes the steps of placing one or more transmitters, at various positions in a plurality of transmitter holes, and placing a plurality of receivers in a plurality of receiver holes. The transmitters generate electromagnetic signals which diffuse through a medium, such as earth, toward the receivers. The measured diffusion field data H is then transformed into wavefield data U. The travel times corresponding to the wavefield data U, are then obtained, by charting the wavefield data U, using a different regularization parameter [alpha] for each transform. The desired property of the medium, such as conductivity, is then derived from the velocity, which in turn is constructed from the wavefield data U using ray tomography. 13 figures.

Constraints and stability in vector theories with spontaneous Lorentz violation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bluhm, Robert; Gagne, Nolan L.; Potting, Robertus

2008-06-15

Vector theories with spontaneous Lorentz violation, known as bumblebee models, are examined in flat spacetime using a Hamiltonian constraint analysis. In some of these models, Nambu-Goldstone modes appear with properties similar to photons in electromagnetism. However, depending on the form of the theory, additional modes and constraints can appear that have no counterparts in electromagnetism. An examination of these constraints and additional degrees of freedom, including their nonlinear effects, is made for a variety of models with different kinetic and potential terms, and the results are compared with electromagnetism. The Hamiltonian constraint analysis also permits an investigation of the stabilitymore » of these models. For certain bumblebee theories with a timelike vector, suitable restrictions of the initial-value solutions are identified that yield ghost-free models with a positive Hamiltonian. In each case, the restricted phase space is found to match that of electromagnetism in a nonlinear gauge.« less

Design and field tests of an access-tube soil water sensor

USDA-ARS?s Scientific Manuscript database

Accurate soil profile water content monitoring at multiple depths until now, has been possible only using the neutron probe (NP), but with great effort and at infrequent time intervals. Despite the existence of several electromagnetic sensor systems for profile water content measurements, accuracy ...

FDEMS Sensing for Automated Intelligent Processing of PMR-15

NASA Technical Reports Server (NTRS)

Kranbuehl, David E.; Hood, D. K.; Rogozinski, J.; Barksdale, R.; Loos, Alfred C.; McRae, Doug

1993-01-01

The purpose of this grant was to develop frequency dependent dielectric measurements, often called FDEMS (frequency dependent electromagnetic sensing), to monitor and intelligently control the cure process in PMR-15, a stoichiometric mixture of a nadic ester, dimethyl ester, and methylendianiline in a monomor ratio.

Hidden momentum of electrons, nuclei, atoms, and molecules

NASA Astrophysics Data System (ADS)

Cameron, Robert P.; Cotter, J. P.

2018-04-01

We consider the positions and velocities of electrons and spinning nuclei and demonstrate that these particles harbour hidden momentum when located in an electromagnetic field. This hidden momentum is present in all atoms and molecules, however it is ultimately canceled by the momentum of the electromagnetic field. We point out that an electron vortex in an electric field might harbour a comparatively large hidden momentum and recognize the phenomenon of hidden hidden momentum.

DEMONSTRATION REPORT: Demonstration of Advanced Geophysics and Classification Technologies on Munitions Response Sites Former Fort Ord, Monterey County, CA

DTIC Science & Technology

2017-06-01

DGM Digital Geophysical Mapping DTSC California Department of Toxic Substances Control EM Electromagnetic EPA U.S. Environmental...land mines, pyrotechnics, bombs , and demolition materials. Surface sweeps identified MEC items throughout Units 11 and 12, including 37mm, 40mm, 57mm...electromagnetic ( EM ) data are being collected. If no GPS readings are collected during that period, the most recent GPS position and the platform

Magnetic radiation shielding - An idea whose time has returned?

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.

1991-01-01

One solution to the problem of shielding crew from particulate radiation in space is to use active electromagnetic shielding. Practical types of shield include the magnetic shield, in which a strong magnetic field diverts charged particles from the crew region, and the magnetic/electrostatic plasma shield, in which an electrostatic field shields the crew from positively charged particles, while a magnetic field confines electrons from the space plasma to provide charge neutrality. Advances in technology include high-strength composite materials, high-temperature superconductors, numerical computational solutions to particle transport in electromagnetic fields, and a technology base for construction and operation of large superconducting magnets. These advances make electromagnetic shielding a practical alternative for near-term future missions.

Design and Analysis of an Electromagnetic Thrust Bearing

NASA Technical Reports Server (NTRS)

Banerjee, Bibhuti; Rao, Dantam K.

1996-01-01

A double-acting electromagnetic thrust bearing is normally used to counter the axial loads in many rotating machines that employ magnetic bearings. It essentially consists of an actuator and drive electronics. Existing thrust bearing design programs are based on several assumptions. These assumptions, however, are often violated in practice. For example, no distinction is made between maximum external loads and maximum bearing forces, which are assumed to be identical. Furthermore, it is assumed that the maximum flux density in the air gap occurs at the nominal gap position of the thrust runner. The purpose of this paper is to present a clear theoretical basis for the design of the electromagnetic thrust bearing which obviates such assumptions.

Grapple fixture for use with electromagnetic attachment mechanism

NASA Technical Reports Server (NTRS)

Monford, Jr., Leo G. (Inventor)

1995-01-01

An electromagnetic attachment mechanism for use as an end effector of a remote manipulator system. A pair of electromagnets 15A,15B, each with a U-shaped magnetic core with a pull-in coil 34 and two holding coils 35,36 are mounted by a spring suspension system 38,47 on a base plate 25 of the mechanism housing 30 with end pole pieces 21,22 adapted to move through openings in the base plate when the attractive force of the electromagnets is exerted on a strike plate 65 of a grapple fixture 20 affixed to a target object 14. The pole pieces are spaced by an air gap from the strike plate when the mechanism first contacts the grapple fixture. An individual control circuit and power source is provided for the pull-in coil and one holding coil of each electromagnet. A back-up control circuit connected to the two power sources and a third power source is provided for the remaining holding coils. When energized, the pull-in coils overcome the suspension system and air gap and are automatically de-energized when the pole pieces move to grapple and impose a preload force across the grapple interface. A battery back-up 89A,89B is a redundant power source for each electromagnet in each individual control circuit and is automatically connected upon failure of the primary power source. A centerline mounted camera 31 and video monitor 70 are used in cooperation with a target pattern 19 on the reflective surface 67 of the strike plate to effect targeting and alignment.

Hydrometry's classical and Innovative methods and tools comparison for Stara river flows at Agios Germanos monitoring station in north-west Greece.

NASA Astrophysics Data System (ADS)

Filintas, Agathos, , Dr; Hatzigiannakis, Evagellos, , Dr; Arampatzis, George, , Dr; Ilias, Andreas; Panagopoulos, Andreas, , Dr; Hatzispiroglou, Ioannis

2015-04-01

The aim of the present study is a thorough comparison of hydrometry's conventional and innovative methods-tools for river flow monitoring. A case study was conducted in Stara river at Agios Germanos monitoring station (northwest Greece), in order to investigate possible deviations between conventional and innovative methods-tools on river flow velocity and discharge. For this study, two flowmeters were used, which manufac-tured in 2013 (OTT Messtechnik Gmbh, 2013), as follows: a) A conventional propeller flow velocity meter (OTT-Model C2) which is a me-chanical current flow meter with a certification of calibration BARGO, operated with a rod and a relocating device, along with a digital measuring device including an elec-tronic flow calculator, data logger and real time control display unit. The flowmeter has a measurement velocity range 0.025-4.000 m/s. b) An innovative electromagnetic flowmeter (OTT-Model MF pro) which it is con-sisted of a compact and light-weight sensor and a robust handheld unit. Both system components are designed to be attached to conventional wading rods. The electromag-netic flowmeter uses Faraday's Law of electromagnetic induction to measure the process flow. When an electrically conductive fluid flows along the meter, an electrode voltage is induced between a pair of electrodes placed at right angles to the direction of mag-netic field. The electrode voltage is directly proportional to the average fluid velocity. The electromagnetic flowmeter was operated with a rod and relocating device, along with a digital measuring device with various logging and graphical capabilities and vari-ous methods of velocity measurement (ISO/USGS standards). The flowmeter has a measurement velocity range 0.000-6.000 m/s. The river flow data were averaged over a pair measurement of 60+60 seconds and the measured river water flow velocity, depths and widths of the segments were used for the estimation of cross-section's mean flow velocity in each measured segment. Then it was used the mid-section method for the overall discharge calculation of all segments flow area. The cross-section characteristics, the river flow velocity of segments and the mean water flow velocity and discharge total profile were measured, calculated and an-notated respectively. A series of concurrent conventional and innovative (electromag-netic) flow measurements were performed during 2014. The results and statistical analysis showed that Froude number during the measurement period in all cases was Fr<1 which means that the water flow of the Stara river is classified as subcritical flow. The 12 months' study showed various advantages for the elec-tromagnetic sensor that is virtually maintenance-free because there are no moving parts, no calibration was required in practice, and it can be used even in the lowest water ve-locities from 0.000 m/s. Moreover, based on the concurrent hydromeasurements of the Stara River, on the velocity and discharge modelling and the statistical analysis, it was found that there was not a significant statistical difference (α=0.05) between mean velocity measured with a) conventional and b) electromagnetic method which seems to be more accurate in low velocities where a significant statistical difference was found. Acknowledgments Data in this study are collected in the framework of the elaboration of the national water resources monitoring network, supervised by the Special Secretariat for Water-Hellenic Ministry for the Environment and Climate Change. This project is elaborated in the framework of the operational program "Environment and Sustainable Development" which is co-funded by the National Strategic Reference Framework (NSRF) and the Public Investment Program (PIP).

Radiofrequency radiation injures trees around mobile phone base stations.

PubMed

Waldmann-Selsam, Cornelia; Balmori-de la Puente, Alfonso; Breunig, Helmut; Balmori, Alfonso

2016-12-01

In the last two decades, the deployment of phone masts around the world has taken place and, for many years, there has been a discussion in the scientific community about the possible environmental impact from mobile phone base stations. Trees have several advantages over animals as experimental subjects and the aim of this study was to verify whether there is a connection between unusual (generally unilateral) tree damage and radiofrequency exposure. To achieve this, a detailed long-term (2006-2015) field monitoring study was performed in the cities of Bamberg and Hallstadt (Germany). During monitoring, observations and photographic recordings of unusual or unexplainable tree damage were taken, alongside the measurement of electromagnetic radiation. In 2015 measurements of RF-EMF (Radiofrequency Electromagnetic Fields) were carried out. A polygon spanning both cities was chosen as the study site, where 144 measurements of the radiofrequency of electromagnetic fields were taken at a height of 1.5m in streets and parks at different locations. By interpolation of the 144 measurement points, we were able to compile an electromagnetic map of the power flux density in Bamberg and Hallstadt. We selected 60 damaged trees, in addition to 30 randomly selected trees and 30 trees in low radiation areas (n=120) in this polygon. The measurements of all trees revealed significant differences between the damaged side facing a phone mast and the opposite side, as well as differences between the exposed side of damaged trees and all other groups of trees in both sides. Thus, we found that side differences in measured values of power flux density corresponded to side differences in damage. The 30 selected trees in low radiation areas (no visual contact to any phone mast and power flux density under 50μW/m 2 ) showed no damage. Statistical analysis demonstrated that electromagnetic radiation from mobile phone masts is harmful for trees. These results are consistent with the fact that damage afflicted on trees by mobile phone towers usually start on one side, extending to the whole tree over time. Copyright © 2016 Elsevier B.V. All rights reserved.

Determination of concrete cover thickness in a reinforced concrete pillar by observation of the scattered electromagnetic field

NASA Astrophysics Data System (ADS)

Di Gregorio, Pietro Paolo; Frezza, Fabrizio; Mangini, Fabio; Pajewski, Lara

2017-04-01

The electromagnetic scattered field by a reinforced concrete structure is calculated by means of frequency-domain numerical simulations and by making use of the scattered-field formulation. The concrete pillar, used as supporting architectural element, is modelled as a parallelepiped shell made of concrete material inside which are present steel bars. In order to make the model simpler, the steel bars are supposed running parallel to the air-pillar interface. To excite the model, a linearly-polarized plane wave impinging normally with respect to the pillars surface, is adopted. We consider two different polarizations in order to determine the most useful in terms of scattered-field sensitivity. Moreover, a preliminary frequency sweep allows us to choose the most suitable operating frequency depending on the dimensions of the pillar cross-section, the steel bars cross-section and the concrete cover. All the three components of the scattered field are monitored along a line just above the interface air-pillar. The electromagnetic properties of the materials employed in this study are present in the literature and, since a frequency-domain technique is adopted, no further approximation is needed. The results obtained for different values of the concrete cover are compared, with the goal of determining the scattered field dependence on the concrete cover thickness. Considering different concrete cover thicknesses, we want to provide an electromagnetic method to obtain this useful parameter by observation of the scattered electromagnetic field. One of the practical applications of this study in the field of Civil Engineering may be the use of ground penetrating radar (GPR) techniques to monitor the thickness of the concrete that separates the metal bars embedded in the pillar from the outer surface. A correct distance is useful because the concrete cover serves as a protection against external agents avoiding corrosion of the bars that might prejudice the reinforced concrete; it ensures also an optimal transmission and distribution of the adhesion forces in the pillar. Acknowledgement This work is a contribution to COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar" (www.GPRadar.eu, www.cost.eu).

Intraluminal laser atherectomy with ultrasound and electromagnetic guidance

NASA Astrophysics Data System (ADS)

Gregory, Kenton W.; Aretz, H. Thomas; Martinelli, Michael A.; LeDet, Earl G.; Hatch, G. F.; Gregg, Richard E.; Sedlacek, Tomas; Haase, Wayne C.

1991-05-01

The MagellanTM coronary laser atherectomy system is described. It uses high- resolution ultrasound imaging and electromagnetic sensing to provide real-time guidance and control of laser therapy in the coronary arteries. The system consists of a flexible catheter, an electromagnetic navigation antenna, a sensor signal processor and a computer for image processing and display. The small, flexible catheter combines an ultrasound transducer and laser delivery optics, aimed at the artery wall, and an electromagnetic receiving sensor. An extra-corporeal electromagnetic transmit antenna, in combination with catheter sensors, locates the position of the ultrasound and laser beams in the artery. Navigation and ultrasound data are processed electronically to produce real-time, transverse, and axial cross-section images of the artery wall at selected locations. By exploiting the ability of ultrasound to image beneath the surface of artery walls, it is possible to identify candidate treatment sites and perform safe radial laser debulking of atherosclerotic plaque with reduced danger of perforation. The utility of the system in plaque identification and ablation is demonstrated with imaging and experimental results.

Rapid Charged Geosynchronous Debris Perturbation Modeling of Electrodynamic Disturbances

NASA Astrophysics Data System (ADS)

Hughes, Joseph; Schaub, Hanspeter

2018-06-01

Charged space objects experience small perturbative torques and forces from their interaction with Earth's magnetic field. These small perturbations can change the orbits of lightweight, uncontrolled debris objects dramatically even over short periods. This paper investigates the effects of the isolated Lorentz force, the effects of including or neglecting this and other electromagnetic perturbations in a full propagation, and then analyzes for which objects electromagnetic effects have the most impact. It is found that electromagnetic forces have a negligible impact on their own. However, if the center of charge is not collocated with the center of mass, electromagnetic torques are produced which do impact the attitude, and thus the position by affecting the direction and magnitude of the solar radiation pressure force. The objects for which electrostatic torques have the most influence are charged above the kilovolt level, have a difference between their center of mass and center of charge, have highly attitude-dependent cross-sectional area, and are not spinning stably about an axis of maximum inertia. Fully coupled numerical simulation illustrate the impact of electromagnetic disturbances through the solar radiation pressure coupling.

Achieving the broader frequency electromagnetic absorber by development of magnetic core-shell composite with tunable shell/core sizes

NASA Astrophysics Data System (ADS)

Cheng, Ye; Guo, Yuhang; Zhang, Zhenya; Dong, Songtao; Liu, Suwei; Wang, Hongying

2018-03-01

Magnetic absorber has been regarded as the advanced electromagnetic energy transfer material to solve the increasingly high frequency electromagnetic interference issue. Even so, the pure magnetic material, in particular magnetic metal nanoparticle, suffering from the poor chemical stability and strong eddy current effect, thus limits it further application. To overcome this shortage, surrounded the magnetic metal nanoparticle (MPs) with insulated oxide shell has been considered to be an efficient route to suppress such an eddy current effect. Meanwhile, the combined insulated shell with good impedance matching feature, shows a positive role on the electromagnetic energy transfer intensity. In this regard, the binary Fe@α-Fe2O3 composite with the average size of ∼ 20 nm was prepared by a facile self-oxidation reaction. Interestingly, both the core diameter and shell thickness is controllable by controlling the oxide degree. The electromagnetic energy transfer performance revealed the maximum absorption frequency bandwidth of the optimal Fe@α-Fe2O3 composite is up to 5.3 G(8.2-13.5 GHz)under a small coating thickness of 1.5 mm.

Poynting vector, energy densities, and pressure of collective transverse electromagnetic fluctuations in unmagnetized plasmas

NASA Astrophysics Data System (ADS)

Schlickeiser, R.

2012-01-01

A systematic calculation of the electromagnetic properties (Poynting vector, electromagnetic energy, and pressure) of the collective transverse fluctuations in unmagnetized plasmas with velocity-anisotropic plasma particle distributions functions is presented. Time-averaged electromagnetic properties for monochromatic weakly damped wave-like fluctuations and space-averaged electromagnetic properties for monochromatic weakly propagating and aperiodic fluctuations are calculated. For aperiodic fluctuations, the Poynting vector as well as the sum of the space-averaged electric and magnetic field energy densities vanish. However, aperiodic fluctuations possess a positive pressure given by its magnetic energy density. This finite pressure density pa of aperiodic fluctuations has important consequences for the dynamics of cosmic unmagnetized plasmas such as the intergalactic medium after reionization. Adopting the standard cosmological evolution model, we show that this additional pressure changes the expansion law of the universe leading to further deceleration. Negative vacuum pressure counterbalances this deceleration to an accelerating universe provided that the negative vacuum pressure is greater than 1.5pa, which we estimate to be of the order 2.1 . 10-16 dyn cm-2.

Rapid Charged Geosynchronous Debris Perturbation Modeling of Electrodynamic Disturbances

NASA Astrophysics Data System (ADS)

Hughes, Joseph; Schaub, Hanspeter

2018-04-01

Charged space objects experience small perturbative torques and forces from their interaction with Earth's magnetic field. These small perturbations can change the orbits of lightweight, uncontrolled debris objects dramatically even over short periods. This paper investigates the effects of the isolated Lorentz force, the effects of including or neglecting this and other electromagnetic perturbations in a full propagation, and then analyzes for which objects electromagnetic effects have the most impact. It is found that electromagnetic forces have a negligible impact on their own. However, if the center of charge is not collocated with the center of mass, electromagnetic torques are produced which do impact the attitude, and thus the position by affecting the direction and magnitude of the solar radiation pressure force. The objects for which electrostatic torques have the most influence are charged above the kilovolt level, have a difference between their center of mass and center of charge, have highly attitude-dependent cross-sectional area, and are not spinning stably about an axis of maximum inertia. Fully coupled numerical simulation illustrate the impact of electromagnetic disturbances through the solar radiation pressure coupling.

Geophysical investigation at an existing landfill, Badger Army Ammunition Plant, Baraboo, Wisconsin. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whitten, C.B.; Sjostrom, K.J.

1991-04-01

Ground-water contaminants were found in ground-water monitoring wells at the existing landfill. More wells to define the horizontal and vertical extent of the contaminant plume are to be installed. Geophysical techniques (electro-magnetic induction, vertical electrical resistivity, and horizontal resistivity profiling) were used to map the extent of the contaminant plume. Using the geophysical, ground-water elevation, and geologic data, five anomalous areas south and east of the landfill were identified as locations for additional ground-water monitoring wells.

Detector sustainability improvements at LCLS

NASA Astrophysics Data System (ADS)

Browne, Michael C.; Carini, Gabriella; DePonte, Daniel P.; Galtier, Eric C.; Hart, Philip A.; Koralek, J. D.; Mitra, Ankush; Nakahara, Kazutaka

2017-06-01

The Linac Coherent Light Source (LCLS) poses a number of daunting and often unusual challenges to maintaining X-ray detectors, such as proximity to liquid-sample injectors, complex setups with moving components, intense X-ray and optical laser light, and Electromagnetic Pulse (EMP). The Detector and Sample Environment departments at LCLS are developing an array of engineering, monitoring, and administrative controls solutions to better address these issues. These include injector improvements and monitoring methods, fast online damage recognition algorithms, EMP mapping and protection, actively cooled filters, and more.

Multi-instrument Observations of Transient Luminous Events Associated with a Small-scale Winter Thunderstorm

NASA Astrophysics Data System (ADS)

Kolmasova, I.; Santolik, O.; Spurny, P.; Borovicka, J.; Mlynarczyk, J.; Popek, M.; Lan, R.; Uhlir, L.; Diendorfer, G.; Slosiar, R.

2017-12-01

We present observations of transient luminous events (TLEs) produced by a small-scale winter thunderstorm which occurred on 2 April 2017 in the southwest of Czechia. Elves, sprites and associated positive lightning strokes have been simultaneously recorded by different observational techniques. Optical data include video recordings of TLEs from Nydek (Czechia) and data recorded by high time-resolution photometers at several stations of the Czech fireball network which measured the all-sky brightness originating from lightning return strokes. Electromagnetic data sets include 3-component VLF measurements conducted in Rustrel (France), 2-component ELF measurements recorded at the Hylaty station (Poland) and signal intensity variations of a VLF transmitter (DHO38, Rhauderfehn, Germany) recorded in Bojnice (Slovakia). Optical and electromagnetic data are completed by positions and peak currents of all strokes recorded during the observed thunderstorm by the EUCLID lightning detection network. We focus our analysis on positive lightning discharges with high peak currents and we compare properties of those which produced TLE with properties of discharges for which TLE was not detected. The current moment waveforms and charge moment changes associated with the TLE events are reconstructed from the ELF electromagnetic signals. Obtained current moment waveforms show excellent agreement with high time-resolution optical data.

Superconducting-electromagnetic hybrid bearing using YBCO bulk blocks for passive axial levitation

NASA Astrophysics Data System (ADS)

Nicolsky, R.; de Andrade, R., Jr.; Ripper, A.; David, D. F. B.; Santisteban, J. A.; Stephan, R. M.; Gawalek, W.; Habisreuther, T.; Strasser, T.

2000-06-01

A superconducting/electromagnetic hybrid bearing has been designed using active radial electromagnetic positioning and a superconducting passive axial levitator. This bearing has been tested for an induction machine with a vertical shaft. The prototype was conceived as a four-pole, two-phase induction machine using specially designed stator windings for delivering torque and radial positioning simultaneously. The radial bearing uses four eddy-current sensors, displaced 90° from each other, for measuring the shaft position and a PID control system for feeding back the currents. The stator windings have been adapted from the ones of a standard induction motor. The superconducting axial bearing has been assembled with commercial NdFeB permanent magnets and a set of seven top-seeded-melt-textured YBCO large-grain cylindrical blocks. The bearing set-up was previously simulated by a finite element method for different permanent magnet-superconductor block configurations. The stiffness of the superconducting axial bearing has been investigated by measuring by a dynamic method the vertical and transversal elastic constants for different field cooling processes. The resulting elastic constants show a linear dependence on the air gap, i.e. the clearance between the permanent magnet assembly and the set of superconducting large-grain blocks, which is dependent on cooling distance.

REMOTE SENSING FOR ENVIRONMENTAL COMPLIANCE MONITORING

EPA Science Inventory

I. Remote Sensing Basics
A. The electromagnetic spectrum demonstrates what we can see both in the visible and beyond the visible part of the spectrum through the use of various types of sensors.
B. Resolution refers to what a remote sensor can see and how often.
1. Sp...

A measurement technique to determine the calibration accuracy of an electromagnetic tracking system to radiation isocenter.

PubMed

Litzenberg, Dale W; Gallagher, Ian; Masi, Kathryn J; Lee, Choonik; Prisciandaro, Joann I; Hamstra, Daniel A; Ritter, Timothy; Lam, Kwok L

2013-08-01

To present and characterize a measurement technique to quantify the calibration accuracy of an electromagnetic tracking system to radiation isocenter. This technique was developed as a quality assurance method for electromagnetic tracking systems used in a multi-institutional clinical hypofractionated prostate study. In this technique, the electromagnetic tracking system is calibrated to isocenter with the manufacturers recommended technique, using laser-based alignment. A test patient is created with a transponder at isocenter whose position is measured electromagnetically. Four portal images of the transponder are taken with collimator rotations of 45° 135°, 225°, and 315°, at each of four gantry angles (0°, 90°, 180°, 270°) using a 3×6 cm2 radiation field. In each image, the center of the copper-wrapped iron core of the transponder is determined. All measurements are made relative to this transponder position to remove gantry and imager sag effects. For each of the 16 images, the 50% collimation edges are identified and used to find a ray representing the rotational axis of each collimation edge. The 16 collimator rotation rays from four gantry angles pass through and bound the radiation isocenter volume. The center of the bounded region, relative to the transponder, is calculated and then transformed to tracking system coordinates using the transponder position, allowing the tracking system's calibration offset from radiation isocenter to be found. All image analysis and calculations are automated with inhouse software for user-independent accuracy. Three different tracking systems at two different sites were evaluated for this study. The magnitude of the calibration offset was always less than the manufacturer's stated accuracy of 0.2 cm using their standard clinical calibration procedure, and ranged from 0.014 to 0.175 cm. On three systems in clinical use, the magnitude of the offset was found to be 0.053±0.036, 0.121±0.023, and 0.093±0.013 cm. The method presented here provides an independent technique to verify the calibration of an electromagnetic tracking system to radiation isocenter. The calibration accuracy of the system was better than the 0.2 cm accuracy stated by the manufacturer. However, it should not be assumed to be zero, especially for stereotactic radiation therapy treatments where planning target volume margins are very small.

On the use of particle filters for electromagnetic tracking in high dose rate brachytherapy

NASA Astrophysics Data System (ADS)

Götz, Th I.; Lahmer, G.; Brandt, T.; Kallis, K.; Strnad, V.; Bert, Ch; Hensel, B.; Tomé, A. M.; Lang, E. W.

2017-10-01

Modern radiotherapy of female breast cancers often employs high dose rate brachytherapy, where a radioactive source is moved inside catheters, implanted in the female breast, according to a prescribed treatment plan. Source localization relative to the patient’s anatomy is determined with solenoid sensors whose spatial positions are measured with an electromagnetic tracking system. Precise sensor dwell position determination is of utmost importance to assure irradiation of the cancerous tissue according to the treatment plan. We present a hybrid data analysis system which combines multi-dimensional scaling with particle filters to precisely determine sensor dwell positions in the catheters during subsequent radiation treatment sessions. Both techniques are complemented with empirical mode decomposition for the removal of superimposed breathing artifacts. We show that the hybrid model robustly and reliably determines the spatial positions of all catheters used during the treatment and precisely determines any deviations of actual sensor dwell positions from the treatment plan. The hybrid system only relies on sensor positions measured with an EMT system and relates them to the spatial positions of the implanted catheters as initially determined with a computed x-ray tomography.

Lévy noise improves the electrical activity in a neuron under electromagnetic radiation.

PubMed

Wu, Juan; Xu, Yong; Ma, Jun

2017-01-01

As the fluctuations of the internal bioelectricity of nervous system is various and complex, the external electromagnetic radiation induced by magnet flux on membrane can be described by the non-Gaussian type distribution of Lévy noise. Thus, the electrical activities in an improved Hindmarsh-Rose model excited by the external electromagnetic radiation of Lévy noise are investigated and some interesting modes of the electrical activities are exhibited. The external electromagnetic radiation of Lévy noise leads to the mode transition of the electrical activities and spatial phase, such as from the rest state to the firing state, from the spiking state to the spiking state with more spikes, and from the spiking state to the bursting state. Then the time points of the firing state versus Lévy noise intensity are depicted. The increasing of Lévy noise intensity heightens the neuron firing. Also the stationary probability distribution functions of the membrane potential of the neuron induced by the external electromagnetic radiation of Lévy noise with different intensity, stability index and skewness papremeters are analyzed. Moreover, through the positive largest Lyapunov exponent, the parameter regions of chaotic electrical mode of the neuron induced by the external electromagnetic radiation of Lévy noise distribution are detected.

Lévy noise improves the electrical activity in a neuron under electromagnetic radiation

PubMed Central

Wu, Juan; Ma, Jun

2017-01-01

As the fluctuations of the internal bioelectricity of nervous system is various and complex, the external electromagnetic radiation induced by magnet flux on membrane can be described by the non-Gaussian type distribution of Lévy noise. Thus, the electrical activities in an improved Hindmarsh-Rose model excited by the external electromagnetic radiation of Lévy noise are investigated and some interesting modes of the electrical activities are exhibited. The external electromagnetic radiation of Lévy noise leads to the mode transition of the electrical activities and spatial phase, such as from the rest state to the firing state, from the spiking state to the spiking state with more spikes, and from the spiking state to the bursting state. Then the time points of the firing state versus Lévy noise intensity are depicted. The increasing of Lévy noise intensity heightens the neuron firing. Also the stationary probability distribution functions of the membrane potential of the neuron induced by the external electromagnetic radiation of Lévy noise with different intensity, stability index and skewness papremeters are analyzed. Moreover, through the positive largest Lyapunov exponent, the parameter regions of chaotic electrical mode of the neuron induced by the external electromagnetic radiation of Lévy noise distribution are detected. PMID:28358824

Band-notched spiral antenna

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeon, Jae; Chang, John

A band-notched spiral antenna having one or more spiral arms extending from a radially inner end to a radially outer end for transmitting or receiving electromagnetic radiation over a frequency range, and one or more resonance structures positioned adjacent one or more segments of the spiral arm associated with a notch frequency band or bands of the frequency range so as to resonate and suppress the transmission or reception of electromagnetic radiation over said notch frequency band or bands.

Hand-Held EMI Sensor Combined with Inertial Positioning for Cued UXO Discrimination - APG Standardized UXO Test Site

DTIC Science & Technology

2013-04-01

Measurement Tracking System (SAINT) with an advanced hand-held, time-domain electromagnetic sensor (TEM-HH) and document classification performance at...rejecting 77% of the clutter. 15. SUBJECT TERMS EMI, electromagnetic induction, UXO classification, UXO, IMU, inertial measurement unit, 16. SECURITY...U c. THIS PAGE U UU 19b. TELEPHONE NUMBER (include area code) 919-677-1560 Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. Z39.18

VHF Omnidirectional Radio Range (VOR) Electromagnetic Spectrum Measurements.

DTIC Science & Technology

1978-10-18

MAINTENANCE AND INSPECTION OF VOR, DVOR FACILITIES. 9-42 mouce & Io 10/18/78 Page 9-1 VHF OMNI-DIRECTIONAL RADIO RANGE (VOR) ELECTROMAGNETIC SPECTRUM...developed by the rotating sideband pattern 0r Pattern shown at North 00 North position Reference30 R--Variable ....uRlerent Cardioid-shaped Field Pattern...to their respective antenna pairs (which are 1800 out of phase with each other). This combination creates a two lobe field pattern rotating at 30 rps

Real-time supernova neutrino burst monitor at Super-Kamiokande

NASA Astrophysics Data System (ADS)

Abe, K.; Haga, Y.; Hayato, Y.; Ikeda, M.; Iyogi, K.; Kameda, J.; Kishimoto, Y.; Miura, M.; Moriyama, S.; Nakahata, M.; Nakano, Y.; Nakayama, S.; Sekiya, H.; Shiozawa, M.; Suzuki, Y.; Takeda, A.; Tanaka, H.; Tomura, T.; Ueno, K.; Wendell, R. A.; Yokozawa, T.; Irvine, T.; Kajita, T.; Kametani, I.; Kaneyuki, K.; Lee, K. P.; McLachlan, T.; Nishimura, Y.; Richard, E.; Okumura, K.; Labarga, L.; Fernandez, P.; Berkman, S.; Tanaka, H. A.; Tobayama, S.; Gustafson, J.; Kearns, E.; Raaf, J. L.; Stone, J. L.; Sulak, L. R.; Goldhaber, M.; Carminati, G.; Kropp, W. R.; Mine, S.; Weatherly, P.; Renshaw, A.; Smy, M. B.; Sobel, H. W.; Takhistov, V.; Ganezer, K. S.; Hartfiel, B. L.; Hill, J.; Keig, W. E.; Hong, N.; Kim, J. Y.; Lim, I. T.; Akiri, T.; Himmel, A.; Scholberg, K.; Walter, C. W.; Wongjirad, T.; Ishizuka, T.; Tasaka, S.; Jang, J. S.; Learned, J. G.; Matsuno, S.; Smith, S. N.; Hasegawa, T.; Ishida, T.; Ishii, T.; Kobayashi, T.; Nakadaira, T.; Nakamura, K.; Oyama, Y.; Sakashita, K.; Sekiguchi, T.; Tsukamoto, T.; Suzuki, A. T.; Takeuchi, Y.; Bronner, C.; Hirota, S.; Huang, K.; Ieki, K.; Kikawa, T.; Minamino, A.; Murakami, A.; Nakaya, T.; Suzuki, K.; Takahashi, S.; Tateishi, K.; Fukuda, Y.; Choi, K.; Itow, Y.; Mitsuka, G.; Mijakowski, P.; Hignight, J.; Imber, J.; Jung, C. K.; Yanagisawa, C.; Wilking, M. J.; Ishino, H.; Kibayashi, A.; Koshio, Y.; Mori, T.; Sakuda, M.; Yamaguchi, R.; Yano, T.; Kuno, Y.; Tacik, R.; Kim, S. B.; Okazawa, H.; Choi, Y.; Nishijima, K.; Koshiba, M.; Suda, Y.; Totsuka, Y.; Yokoyama, M.; Martens, K.; Marti, Ll.; Vagins, M. R.; Martin, J. F.; de Perio, P.; Konaka, A.; Chen, S.; Zhang, Y.; Connolly, K.; Wilkes, R. J.

2016-08-01

We present a real-time supernova neutrino burst monitor at Super-Kamiokande (SK). Detecting supernova explosions by neutrinos in real time is crucial for giving a clear picture of the explosion mechanism. Since the neutrinos are expected to come earlier than light, a fast broadcasting of the detection may give astronomers a chance to make electromagnetic radiation observations of the explosions right at the onset. The role of the monitor includes a fast announcement of the neutrino burst detection to the world and a determination of the supernova direction. We present the online neutrino burst detection system and studies of the direction determination accuracy based on simulations at SK.

An accurate method to quantify breathing-induced prostate motion for patients implanted with electromagnetic transponders.

PubMed

Giandini, Tommaso; Panaino, Costanza M V; Avuzzi, Barbara; Morlino, Sara; Villa, Sergio; Bedini, Nice; Carabelli, Gabriele; Frasca, Sarah C; Romanyukha, Anna; Rosenfeld, Anatoly; Pignoli, Emanuele; Valdagni, Riccardo; Carrara, Mauro

2017-03-24

To validate and apply a method for the quantification of breathing-induced prostate motion (BIPM) for patients treated with radiotherapy and implanted with electromagnetic transponders for prostate localization and tracking. For the analysis of electromagnetic transponder signal, dedicated software was developed and validated with a programmable breathing simulator phantom. The software was then applied to 1,132 radiotherapy fractions of 30 patients treated in supine position, and to a further 61 fractions of 2 patients treated in prone position. Application of the software in phantom demonstrated reliability of the developed method in determining simulated breathing frequencies and amplitudes. For supine patients, the in vivo analysis of BIPM resulted in median (maximum) amplitudes of 0.10 mm (0.35 mm), 0.24 mm (0.66 mm), and 0.17 mm (0.61 mm) in the left-right (LR), cranio-caudal (CC), and anterior-posterior (AP) directions, respectively. Breathing frequency ranged between 7.73 and 29.43 breaths per minute. For prone patients, the ranges of the BIPM amplitudes were 0.1-0.5 mm, 0.5-1.3 mm, and 0.7-1.7 mm in the LR, CC, and AP directions, respectively. The developed method was able to detect the BIPM with sub-millimeter accuracy. While for patients treated in supine position the BIPM represents a reduced source of treatment uncertainty, for patients treated in prone position, it can be higher than 3 mm.

Electromagnetic field analysis and modeling of a relative position detection sensor for high speed maglev trains.

PubMed

Xue, Song; He, Ning; Long, Zhiqiang

2012-01-01

The long stator track for high speed maglev trains has a tooth-slot structure. The sensor obtains precise relative position information for the traction system by detecting the long stator tooth-slot structure based on nondestructive detection technology. The magnetic field modeling of the sensor is a typical three-dimensional (3-D) electromagnetic problem with complex boundary conditions, and is studied semi-analytically in this paper. A second-order vector potential (SOVP) is introduced to simplify the vector field problem to a scalar field one, the solution of which can be expressed in terms of series expansions according to Multipole Theory (MT) and the New Equivalent Source (NES) method. The coefficients of the expansions are determined by the least squares method based on the boundary conditions. Then, the solution is compared to the simulation result through Finite Element Analysis (FEA). The comparison results show that the semi-analytical solution agrees approximately with the numerical solution. Finally, based on electromagnetic modeling, a difference coil structure is designed to improve the sensitivity and accuracy of the sensor.

Electromagnetic Field Analysis and Modeling of a Relative Position Detection Sensor for High Speed Maglev Trains

PubMed Central

Xue, Song; He, Ning; Long, Zhiqiang

2012-01-01

The long stator track for high speed maglev trains has a tooth-slot structure. The sensor obtains precise relative position information for the traction system by detecting the long stator tooth-slot structure based on nondestructive detection technology. The magnetic field modeling of the sensor is a typical three-dimensional (3-D) electromagnetic problem with complex boundary conditions, and is studied semi-analytically in this paper. A second-order vector potential (SOVP) is introduced to simplify the vector field problem to a scalar field one, the solution of which can be expressed in terms of series expansions according to Multipole Theory (MT) and the New Equivalent Source (NES) method. The coefficients of the expansions are determined by the least squares method based on the boundary conditions. Then, the solution is compared to the simulation result through Finite Element Analysis (FEA). The comparison results show that the semi-analytical solution agrees approximately with the numerical solution. Finally, based on electromagnetic modeling, a difference coil structure is designed to improve the sensitivity and accuracy of the sensor. PMID:22778652

Use of borehole and surface geophysics to investigate ground-water quality near a road-deicing salt-storage facility, Valparaiso, Indiana

USGS Publications Warehouse

Risch, M.R.; Robinson, B.A.

2001-01-01

Two surface surveys of terrain electromagnetic conductivity were used to map the horizontal extent of the saltwater plume in areas without monitoring wells. Background values of terrain conductivity were measured in an area where water-quality and borehole geophysical data did not indicate saline or brackish water. Based on a guideline from previous case studies, the boundaries of the saltwater plume were mapped where terrain conductivity was 1.5 times background. The extent of the saltwater plume, based on terrain conductivity, generally was consistent with the available water-quality and borehole electromagnetic-conductivity data and with directions of ground-water flow determined from water-level altitudes.

Multiple Frequency Contrast Source Inversion Method for Vertical Electromagnetic Profiling: 2D Simulation Results and Analyses

NASA Astrophysics Data System (ADS)

Li, Jinghe; Song, Linping; Liu, Qing Huo

2016-02-01

A simultaneous multiple frequency contrast source inversion (CSI) method is applied to reconstructing hydrocarbon reservoir targets in a complex multilayered medium in two dimensions. It simulates the effects of a salt dome sedimentary formation in the context of reservoir monitoring. In this method, the stabilized biconjugate-gradient fast Fourier transform (BCGS-FFT) algorithm is applied as a fast solver for the 2D volume integral equation for the forward computation. The inversion technique with CSI combines the efficient FFT algorithm to speed up the matrix-vector multiplication and the stable convergence of the simultaneous multiple frequency CSI in the iteration process. As a result, this method is capable of making quantitative conductivity image reconstruction effectively for large-scale electromagnetic oil exploration problems, including the vertical electromagnetic profiling (VEP) survey investigated here. A number of numerical examples have been demonstrated to validate the effectiveness and capacity of the simultaneous multiple frequency CSI method for a limited array view in VEP.

Sensing (un)binding events via surface plasmons: effects of resonator geometry

NASA Astrophysics Data System (ADS)

Antosiewicz, Tomasz J.; Claudio, Virginia; Käll, Mikael

2016-04-01

The resonance conditions of localized surface plasmon resonances (LSPRs) can be perturbed in any number ways making plasmon nanoresonators viable tools in detection of e.g. phase changes, pH, gasses, and single molecules. Precise measurement via LSPR of molecular concentrations hinge on the ability to confidently count the number of molecules attached to a metal resonator and ideally to track binding and unbinding events in real-time. These two requirements make it necessary to rigorously quantify relations between the number of bound molecules and response of plasmonic sensors. This endeavor is hindered on the one hand by a spatially varying response of a given plasmonic nanosensor. On the other hand movement of molecules is determined by stochastic effects (Brownian motion) as well as deterministic flow, if present, in microfluidic channels. The combination of molecular dynamics and the electromagnetic response of the LSPR yield an uncertainty which is little understood and whose effect is often disregarded in quantitative sensing experiments. Using a combination of electromagnetic finite-difference time-domain (FDTD) calculations of the plasmon resonance peak shift of various metal nanosensors (disk, cone, rod, dimer) and stochastic diffusion-reaction simulations of biomolecular interactions on a sensor surface we clarify the interplay between position dependent binding probability and inhomogeneous sensitivity distribution. We show, how the statistical characteristics of the total signal upon molecular binding are determined. The proposed methodology is, in general, applicable to any sensor and any transduction mechanism, although the specifics of implementation will vary depending on circumstances. In this work we focus on elucidating how the interplay between electromagnetic and stochastic effects impacts the feasibility of employing particular shapes of plasmonic sensors for real-time monitoring of individual binding reactions or sensing low concentrations - which characteristics make a given sensor optimal for a given task. We also address the issue of how particular illumination conditions affect the level of uncertainty of the measured signal upon molecular binding.

Development of an electromagnetic imaging system for well bore integrity inspection

NASA Astrophysics Data System (ADS)

Plotnikov, Yuri; Wheeler, Frederick W.; Mandal, Sudeep; Climent, Helene C.; Kasten, A. Matthias; Ross, William

2017-02-01

State-of-the-art imaging technologies for monitoring the integrity of oil and gas well bores are typically limited to the inspection of metal casings and cement bond interfaces close to the first casing region. The objective of this study is to develop and evaluate a novel well-integrity inspection system that is capable of providing enhanced information about the flaw structure and topology of hydrocarbon producing well bores. In order to achieve this, we propose the development of a multi-element electromagnetic (EM) inspection tool that can provide information about material loss in the first and second casing structure as well as information about eccentricity between multiple casing strings. Furthermore, the information gathered from the EM inspection tool will be combined with other imaging modalities (e.g. data from an x-ray backscatter imaging device). The independently acquired data are then fused to achieve a comprehensive assessment of integrity with greater accuracy. A test rig composed of several concentric metal casings with various defect structures was assembled and imaged. Initial test results were obtained with a scanning system design that includes a single transmitting coil and several receiving coils mounted on a single rod. A mechanical linear translation stage was used to move the EM sensors in the axial direction during data acquisition. For simplicity, a single receiving coil and repetitive scans were employed to simulate performance of the designed receiving sensor array system. The resulting electromagnetic images enable the detection of the metal defects in the steel pipes. Responses from several sensors were used to assess the location and amount of material loss in the first and second metal pipe as well as the relative eccentric position between these two pipes. The results from EM measurements and x-ray backscatter simulations demonstrate that data fusion from several sensing modalities can provide an enhanced assessment of flaw structures in producing well bores and potentially allow for early detection of anomalies that if undetected might lead to catastrophic failures.

Spaceborne centrifugal relays for spacecraft propulsion

NASA Technical Reports Server (NTRS)

Ouzidane, Malika

1991-01-01

Acceleration using centrifugal relays is a recently discovered method for the acceleration of spaceborne payloads to high velocity at high thrust. Centrifugal relays are moving rotors which progressively accelerate reaction mass to higher velocities. One important engineering problem consists of accurately tracking the position of the projectiles and rotors and guiding each projectile exactly onto the appropriate guide tracks on each rotor. The topics of this research are the system kinematics and dynamics and the computerized guidance system which will allow the projectile to approach each rotor with exact timing with respect to the rotor rotation period and with very small errors in lateral positions. Kinematics studies include analysis of rotor and projectile positions versus time and projectile/rotor interactions. Guidance studies include a detailed description of the tracking mechanism (interrupt of optical beams) and the aiming mechanism (electromagnetic focusing) including the design of electromagnetic deflection coils and the switching circuitry.

Calculations and experiments concerning lifting force and power in TEMPUS

NASA Technical Reports Server (NTRS)

Zong, J. H.; Szekely, J.; Lohofer, G.

1993-01-01

A critical comparison is reported between the theoretically predicted and experimentally measured values for the electromagnetic lifting force and the heating rates which may be achieved, under simulated microgravity conditions, using the TEMPUS electromagnetic levitation device. The experiments involved the suspending of a metallic sample from one arm of a recording balance, such that it was carefully positioned between the heating and the positioning coils of the levitation device. The net force exerted by the sample was measured as a function of position, the coil currents, and the nature of the sample. Some calculations are also reported regarding the power absorption by the sample. The theoretical predictions, based on the numerical solution of Maxwell's equations using the volume integral technique, were found to be in excellent agreement with the measurements. For the idealized case of a spherical sample, analytical solutions describing the lifting force were also found to agree very well with the computed results.

Improved Position Sensor for Feedback Control of Levitation

NASA Technical Reports Server (NTRS)

Hyers, Robert; Savage, Larry; Rogers, Jan

2004-01-01

An improved optoelectronic apparatus has been developed to provide the position feedback needed for controlling the levitation subsystem of a containerless-processing system. As explained, the advantage of this apparatus over prior optoelectronic apparatuses that have served this purpose stems from the use of an incandescent lamp, instead of a laser, to illuminate the levitated object. In containerless processing, a small object to be processed is levitated (e.g., by use of a microwave, low-frequency electromagnetic, electrostatic, or acoustic field) so that it is not in contact with the wall of the processing chamber or with any other solid object during processing. In the case of electrostatic or low-frequency electromagnetic levitation, real-time measurement of the displacement of the levitated object from its nominal levitation position along the vertical axis (and, in some cases, along one or two horizontal axes) is needed for feedback control of the levitating field.

Association between Exposure to Electromagnetic Fields from High Voltage Transmission Lines and Neurobehavioral Function in Children

PubMed Central

Huang, Jiongli; Tang, Tiantong; Hu, Guocheng; Zheng, Jing; Wang, Yuyu; Wang, Qiang; Su, Jing; Zou, Yunfeng; Peng, Xiaowu

2013-01-01

Background Evidence for a possible causal relationship between exposure to electromagnetic fields (EMF) emitted by high voltage transmission (HVT) lines and neurobehavioral dysfunction in children is insufficient. The present study aims to investigate the association between EMF exposure from HVT lines and neurobehavioral function in children. Methods Two primary schools were chosen based on monitoring data of ambient electromagnetic radiation. A cross-sectional study with 437 children (9 to 13 years old) was conducted. Exposure to EMF from HVT lines was monitored at each school. Information was collected on possible confounders and relevant exposure predictors using standardized questionnaires. Neurobehavioral function in children was evaluated using established computerized neurobehavioral tests. Data was analyzed using multivariable regression models adjusted for relevant confounders. Results After controlling for potential confounding factors, multivariable regression revealed that children attending a school near 500 kV HVT lines had poorer performance on the computerized neurobehavioral tests for Visual Retention and Pursuit Aiming compared to children attending a school that was not in close proximity to HVT lines. Conclusions The results suggest long-term low-level exposure to EMF from HVT lines might have a negative impact on neurobehavioral function in children. However, because of differences in results only for two of four tests achieved statistical significance and potential limitations, more studies are needed to explore the effects of exposure to extremely low frequency EMF on neurobehavioral function and development in children. PMID:23843999

Advancement of wave generation and signal transmission in wire waveguides for structural health monitoring applications

NASA Astrophysics Data System (ADS)

Kropf, M.; Pedrick, M.; Wang, X.; Tittmann, B. R.

2005-05-01

As per the recent advances in remote in situ monitoring of industrial equipment using long wire waveguides (~10m), novel applications of existing wave generation techniques and new acoustic modeling software have been used to advance waveguide technology. The amount of attainable information from an acoustic signal in such a system is limited by transmission through the waveguide along with frequency content of the generated waves. Magnetostrictive, and Electromagnetic generation techniques were investigated in order to maximize acoustic transmission along the waveguide and broaden the range of usable frequencies. Commercial EMAT, Magnetostrictive and piezoelectric disc transducers (through the innovative use of an acoustic horn) were utilized to generate waves in the wire waveguide. Insertion loss, frequency bandwidth and frequency range were examined for each technique. Electromagnetic techniques are shown to allow for higher frequency wave generation. This increases accessibility of dispersion curves providing further versatility in the selection of guided wave modes, thus increasing the sensitivity to physical characteristics of the specimen. Both electromagnetic and magnetostrictive transducers require the use of a ferromagnetic waveguide, typically coupled to a steel wire when considering long transmission lines (>2m). The interface between these wires introduces an acoustic transmission loss. Coupling designs were examined with acoustic finite element software (Coupled-Acoustic Piezoelectric Analysis). Simulations along with experimental results aided in the design of a novel joint which minimizes transmission loss. These advances result in the increased capability of remote sensing using wire waveguides.

The assessment of electromagnetic field radiation exposure for mobile phone users.

PubMed

Buckus, Raimondas; Strukcinskiene, Birute; Raistenskis, Juozas

2014-12-01

During recent years, the widespread use of mobile phones has resulted in increased human ex- posure to electromagnetic field radiation and to health risks. Increased usage of mobile phones at the close proximity raises questions and doubts in safety of mobile phone users. The aim of the study was to assess an electromagnetic field radiation exposure for mobile phone users by measuring electromagnetic field strength in different settings at the distance of 1 to 30 cm from the mobile user. In this paper, the measurements of electric field strength exposure were conducted on different brand of mobile phones by the call-related factors: urban/rural area, indoor/outdoor setting and moving/stationary mode during calls. The different types of mobile phone were placed facing the field probe at 1 cm, 10 cm, 20 cm and 30 cm distance. The highest electric field strength was recorded for calls made in rural area (indoors) while the lowest electric field strength was recorded for calls made in urban area (outdoors). Calls made from a phone in a moving car gave a similar result like for indoor calls; however, calls made from a phone in a moving car exposed electric field strength two times more than that of calls in a standing (motionless) position. Electromagnetic field radiation depends on mobile phone power class and factors, like urban or rural area, outdoor or indoor, moving or motionless position, and the distance of the mobile phone from the phone user. It is recommended to keep a mobile phone in the safe distance of 10, 20 or 30 cm from the body (especially head) during the calls.

2D and 3D graphical representation of the propagation of electromagnetic waves at the interface with a material with general effective complex permittivity and permeability

NASA Astrophysics Data System (ADS)

Diaz, A.; Ramos, J. G.; Friedman, J. S.

2017-09-01

We developed a web-based instructional and research tool that demonstrates the behavior of electromagnetic waves as they propagate through a homogenous medium and through an interface where the second medium can be characterized by an effective complex permittivity and permeability. Either p- or s-polarization wave components can be chosen and the graphical interface includes 2D wave and 3D component representations. The program enables the study of continuity of electromagnetic components, critical angle, Brewster angle, absorption and amplification, behavior of light in sub-unity and negative-index materials, Poynting vector and phase velocity behavior, and positive and negative Goos- Hänchen shifts.

Compact orthogonal NMR field sensor

DOEpatents

Gerald, II, Rex E.; Rathke, Jerome W [Homer Glen, IL

2009-02-03

A Compact Orthogonal Field Sensor for emitting two orthogonal electro-magnetic fields in a common space. More particularly, a replacement inductor for existing NMR (Nuclear Magnetic Resonance) sensors to allow for NMR imaging. The Compact Orthogonal Field Sensor has a conductive coil and a central conductor electrically connected in series. The central conductor is at least partially surrounded by the coil. The coil and central conductor are electrically or electro-magnetically connected to a device having a means for producing or inducing a current through the coil and central conductor. The Compact Orthogonal Field Sensor can be used in NMR imaging applications to determine the position and the associated NMR spectrum of a sample within the electro-magnetic field of the central conductor.

Combining electromagnetic gyro-kinetic particle-in-cell simulations with collisions

NASA Astrophysics Data System (ADS)

Slaby, Christoph; Kleiber, Ralf; Könies, Axel

2017-09-01

It has been an open question whether for electromagnetic gyro-kinetic particle-in-cell (PIC) simulations pitch-angle collisions and the recently introduced pullback transformation scheme (Mishchenko et al., 2014; Kleiber et al., 2016) are consistent. This question is positively answered by comparing the PIC code EUTERPE with an approach based on an expansion of the perturbed distribution function in eigenfunctions of the pitch-angle collision operator (Legendre polynomials) to solve the electromagnetic drift-kinetic equation with collisions in slab geometry. It is shown how both approaches yield the same results for the frequency and damping rate of a kinetic Alfvén wave and how the perturbed distribution function is substantially changed by the presence of pitch-angle collisions.

Electromagnetic Tracking Navigation to Guide Radiofrequency Ablation (RFA) of a Lung Tumor

PubMed Central

Amalou, Hayet; Wood, Bradford J.

2013-01-01

Radiofrequency ablation (RFA) may be an option for patients with lung tumors who have unresectable disease and are not suitable for available palliative modalities. RFA electrode positioning may take several attempts, necessitating multiple imaging acquisitions or continuous use of CT (Computed Tomography). Electromagnetic tracking utilizes miniature sensors integrated with RFA equipment to guide tools in real-time, while referencing to pre-procedure imaging. This technology was demonstrated successfully during a lung tumor ablation, and was more accurate at targeting the tumor, compared to traditional freehand needle insertion. It is possible, although speculative and anecdotal, that more accuracy could prevent unnecessary repositioning punctures and decrease radiation exposure. Electromagnetic tracking has theoretical potential to benefit minimally invasive interventions. PMID:23207535

Analysis of electromagnetic fields on an F-106B aircraft during lightning strikes

NASA Technical Reports Server (NTRS)

Trost, T. F.; Pitts, F. L.

1982-01-01

Information on the exterior electromagnetic environment of an aircraft when it is struck by lightning has been obtained during thunderstorm penetrations with an F-106B aircraft. Electric and magnetic fields were observed, using mainly time-derivative type sensors, with bandwidths to 50 MHz. Lightning pulse lengths ranging from 25 ns to 7 microsec have been recorded. Sufficient high-frequency content was present to excite electromagnetic resonances of the aircraft, and peaks in the frequency spectra of the waveforms in the range 7 to 23 MHz are in agreement with the resonant frequencies determined in laboratory scale-model tests. Both positively and negatively charged strikes were experienced, and most of the data suggest low values of peak current.

FDTD simulations of localization and enhancements on fractal plasmonics nanostructures.

PubMed

Buil, Stéphanie; Laverdant, Julien; Berini, Bruno; Maso, Pierre; Hermier, Jean-Pierre; Quélin, Xavier

2012-05-21

A parallelized 3D FDTD (Finite-Difference Time-Domain) solver has been used to study the near-field electromagnetic intensity upon plasmonics nanostructures. The studied structures are obtained from AFM (Atomic Force Microscopy) topography measured on real disordered gold layers deposited by thermal evaporation under ultra-high vacuum. The simulation results obtained with these 3D metallic nanostructures are in good agreement with previous experimental results: the localization of the electromagnetic intensity in subwavelength areas ("hot spots") is demonstrated; the spectral and polarization dependences of the position of these "hot spots" are also satisfactory; the enhancement factors obtained are realistic compared to the experimental ones. These results could be useful to further our understanding of the electromagnetic behavior of random metal layers.

Programming an Artificial Neural Network Tool for Spatial Interpolation in GIS - A Case Study for Indoor Radio Wave Propagation of WLAN.

PubMed

Sen, Alper; Gümüsay, M Umit; Kavas, Aktül; Bulucu, Umut

2008-09-25

Wireless communication networks offer subscribers the possibilities of free mobility and access to information anywhere at any time. Therefore, electromagnetic coverage calculations are important for wireless mobile communication systems, especially in Wireless Local Area Networks (WLANs). Before any propagation computation is performed, modeling of indoor radio wave propagation needs accurate geographical information in order to avoid the interruption of data transmissions. Geographic Information Systems (GIS) and spatial interpolation techniques are very efficient for performing indoor radio wave propagation modeling. This paper describes the spatial interpolation of electromagnetic field measurements using a feed-forward back-propagation neural network programmed as a tool in GIS. The accuracy of Artificial Neural Networks (ANN) and geostatistical Kriging were compared by adjusting procedures. The feedforward back-propagation ANN provides adequate accuracy for spatial interpolation, but the predictions of Kriging interpolation are more accurate than the selected ANN. The proposed GIS ensures indoor radio wave propagation model and electromagnetic coverage, the number, position and transmitter power of access points and electromagnetic radiation level. Pollution analysis in a given propagation environment was done and it was demonstrated that WLAN (2.4 GHz) electromagnetic coverage does not lead to any electromagnetic pollution due to the low power levels used. Example interpolated electromagnetic field values for WLAN system in a building of Yildiz Technical University, Turkey, were generated using the selected network architectures to illustrate the results with an ANN.

Intraoperative visualization and assessment of electromagnetic tracking error

NASA Astrophysics Data System (ADS)

Harish, Vinyas; Ungi, Tamas; Lasso, Andras; MacDonald, Andrew; Nanji, Sulaiman; Fichtinger, Gabor

2015-03-01

Electromagnetic tracking allows for increased flexibility in designing image-guided interventions, however it is well understood that electromagnetic tracking is prone to error. Visualization and assessment of the tracking error should take place in the operating room with minimal interference with the clinical procedure. The goal was to achieve this ideal in an open-source software implementation in a plug and play manner, without requiring programming from the user. We use optical tracking as a ground truth. An electromagnetic sensor and optical markers are mounted onto a stylus device, pivot calibrated for both trackers. Electromagnetic tracking error is defined as difference of tool tip position between electromagnetic and optical readings. Multiple measurements are interpolated into the thin-plate B-spline transform visualized in real time using 3D Slicer. All tracked devices are used in a plug and play manner through the open-source SlicerIGT and PLUS extensions of the 3D Slicer platform. Tracking error was measured multiple times to assess reproducibility of the method, both with and without placing ferromagnetic objects in the workspace. Results from exhaustive grid sampling and freehand sampling were similar, indicating that a quick freehand sampling is sufficient to detect unexpected or excessive field distortion in the operating room. The software is available as a plug-in for the 3D Slicer platforms. Results demonstrate potential for visualizing electromagnetic tracking error in real time for intraoperative environments in feasibility clinical trials in image-guided interventions.

Programming an Artificial Neural Network Tool for Spatial Interpolation in GIS - A Case Study for Indoor Radio Wave Propagation of WLAN

PubMed Central

Şen, Alper; Gümüşay, M. Ümit; Kavas, Aktül; Bulucu, Umut

2008-01-01

Wireless communication networks offer subscribers the possibilities of free mobility and access to information anywhere at any time. Therefore, electromagnetic coverage calculations are important for wireless mobile communication systems, especially in Wireless Local Area Networks (WLANs). Before any propagation computation is performed, modeling of indoor radio wave propagation needs accurate geographical information in order to avoid the interruption of data transmissions. Geographic Information Systems (GIS) and spatial interpolation techniques are very efficient for performing indoor radio wave propagation modeling. This paper describes the spatial interpolation of electromagnetic field measurements using a feed-forward back-propagation neural network programmed as a tool in GIS. The accuracy of Artificial Neural Networks (ANN) and geostatistical Kriging were compared by adjusting procedures. The feedforward back-propagation ANN provides adequate accuracy for spatial interpolation, but the predictions of Kriging interpolation are more accurate than the selected ANN. The proposed GIS ensures indoor radio wave propagation model and electromagnetic coverage, the number, position and transmitter power of access points and electromagnetic radiation level. Pollution analysis in a given propagation environment was done and it was demonstrated that WLAN (2.4 GHz) electromagnetic coverage does not lead to any electromagnetic pollution due to the low power levels used. Example interpolated electromagnetic field values for WLAN system in a building of Yildiz Technical University, Turkey, were generated using the selected network architectures to illustrate the results with an ANN. PMID:27873854

Detection of significant variation in acoustic output of an electromagnetic lithotriptor.

PubMed

Pishchalnikov, Yuri A; McAteer, James A; Vonderhaar, R Jason; Pishchalnikova, Irina V; Williams, James C; Evan, Andrew P

2006-11-01

We describe the observation of significant instability in the output of an electromagnetic lithotriptor. This instability had a form that was not detected by routine assessment, but rather was observed only by collecting many consecutive shock waves in nonstop regimen. A Dornier DoLi-50 lithotriptor used exclusively for basic research was tested and approved by the regional technician. This assessment included hydrophone measures at select power levels with the collection of about 25 shock waves per setting. Subsequent laboratory characterization used a fiberoptic hydrophone and storage oscilloscope for data acquisition. Waveforms were collected nonstop for hundreds of pulses. Output was typically stable for greater than 1,000 shock waves but substantial fluctuations in acoustic pressures were also observed. For example, output at power level 3 (mean peak positive acoustic pressure +/- SD normally 44 +/- 2 MPa) increased dramatically to greater than 50 MPa or decreased significantly to approximately 30 MPa for hundreds of shock waves. The cause of instability was eventually traced to a faulty lithotriptor power supply. Instability in lithotriptor acoustic output can occur and it may not be detected by routine assessment. Collecting waveforms in a nonstop regimen dramatically increases sampling size, improving the detection of instability. Had the instability that we observed occurred during patient treatment, the energy delivered may well have exceeded the planned dose. Since the potential for adverse effects in lithotripsy increases as the dose is increased, it would be valuable to develop ways to better monitor the acoustic output of lithotriptors.

Understanding interference experiments with polarized light through photon trajectories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanz, A.S.; Davidovic, M.; Bozic, M.

2010-04-15

Bohmian mechanics allows to visualize and understand the quantum-mechanical behavior of massive particles in terms of trajectories. As shown by Bialynicki-Birula, Electromagnetism also admits a hydrodynamical formulation when the existence of a wave function for photons (properly defined) is assumed. This formulation thus provides an alternative interpretation of optical phenomena in terms of photon trajectories, whose flow yields a pictorial view of the evolution of the electromagnetic energy density in configuration space. This trajectory-based theoretical framework is considered here to study and analyze the outcome from Young-type diffraction experiments within the context of the Arago-Fresnel laws. More specifically, photon trajectoriesmore » in the region behind the two slits are obtained in the case where the slits are illuminated by a polarized monochromatic plane wave. Expressions to determine electromagnetic energy flow lines and photon trajectories within this scenario are provided, as well as a procedure to compute them in the particular case of gratings totally transparent inside the slits and completely absorbing outside them. As is shown, the electromagnetic energy flow lines obtained allow to monitor at each point of space the behavior of the electromagnetic energy flow and, therefore, to evaluate the effects caused on it by the presence (right behind each slit) of polarizers with the same or different polarization axes. This leads to a trajectory-based picture of the Arago-Fresnel laws for the interference of polarized light.« less

Self-assembling fluidic machines

NASA Astrophysics Data System (ADS)

Grzybowski, Bartosz A.; Radkowski, Michal; Campbell, Christopher J.; Lee, Jessamine Ng; Whitesides, George M.

2004-03-01

This letter describes dynamic self-assembly of two-component rotors floating at the interface between liquid and air into simple, reconfigurable mechanical systems ("machines"). The rotors are powered by an external, rotating magnetic field, and their positions within the interface are controlled by: (i) repulsive hydrodynamic interactions between them and (ii) by localized magnetic fields produced by an array of small electromagnets located below the plane of the interface. The mechanical functions of the machines depend on the spatiotemporal sequence of activation of the electromagnets.

Creation of an anti-imaging system using binary optics.

PubMed

Wang, Haifeng; Lin, Jian; Zhang, Dawei; Wang, Yang; Gu, Min; Urbach, H P; Gan, Fuxi; Zhuang, Songlin

2016-09-13

We present a concealing method in which an anti-point spread function (APSF) is generated using binary optics, which produces a large-scale dark area in the focal region that can hide any object located within it. This result is achieved by generating two identical PSFs of opposite signs, one consisting of positive electromagnetic waves from the zero-phase region of the binary optical element and the other consisting of negative electromagnetic waves from the pi-phase region of the binary optical element.

Creation of an anti-imaging system using binary optics

PubMed Central

Wang, Haifeng; Lin, Jian; Zhang, Dawei; Wang, Yang; Gu, Min; Urbach, H. P.; Gan, Fuxi; Zhuang, Songlin

2016-01-01

We present a concealing method in which an anti-point spread function (APSF) is generated using binary optics, which produces a large-scale dark area in the focal region that can hide any object located within it. This result is achieved by generating two identical PSFs of opposite signs, one consisting of positive electromagnetic waves from the zero-phase region of the binary optical element and the other consisting of negative electromagnetic waves from the pi-phase region of the binary optical element. PMID:27620068

Electromagnetic navigated condylar positioning after high oblique sagittal split osteotomy of the mandible: a guided method to attain pristine temporomandibular joint conditions.

PubMed

Berger, Moritz; Nova, Igor; Kallus, Sebastian; Ristow, Oliver; Eisenmann, Urs; Dickhaus, Hartmut; Engel, Michael; Freudlsperger, Christian; Hoffmann, Jürgen; Seeberger, Robin

2018-05-01

Reproduction of the exact preoperative proximal-mandible position after osteotomy in orthognathic surgery is difficult to achieve. This clinical pilot study evaluated an electromagnetic (EM) navigation system for condylar positioning after high-oblique sagittal split osteotomy (HSSO). After HSSO as part of 2-jaw surgery, the position of 10 condyles was intraoperatively guided by an EM navigation system. As controls, 10 proximal segments were positioned by standard manual replacement. Accuracy was measured by pre- and postoperative cone beam computed tomography imaging. Overall, EM condyle repositioning was equally accurate compared with manual repositioning (P > .05). Subdivided into 3 axes, significant differences could be identified (P < .05). Nevertheless, no significantly and clinically relevant dislocations of the proximal segment of either the EM or the manual repositioning method could be shown (P > .05). This pilot study introduces a guided method for proximal segment positioning after HSSO by applying the intraoperative EM system. The data demonstrate the high accuracy of EM navigation, although manual replacement of the condyles could not be surpassed. However, EM navigation can avoid clinically hidden, severe malpositioning of the condyles. Copyright © 2017 Elsevier Inc. All rights reserved.

Investigation of geotechnical parameters from CSEM mapping and monitoring data at the oases Kharga and Baris of Sahara desert, Egypt

NASA Astrophysics Data System (ADS)

Hachay, Olga; Khachay, Oleg; Attia, Magdy; Khalil, Ahmed; Mekkawi, Mahmoud; Soliman, Mamdouh

2016-04-01

The site of investigation, oasis Kharga, is located at about 600 km south of Cairo, Egypt; Baris is about 90 km from Kharga also to south and towards more inside the desert. The work was aimed to investigate the rock mass stability at Baris and to estimate the water intake in the Oasis Kharga. A controlled source electromagnetic (CSEM) approach developed earlier by IGF UB RAS (Geophysical Federal Institute, Ural Branch of Russian Academy of Science) is applied to image the ranked deformation levels in the massive structure of the Baris. The wide profile system of observation has been used to monitor the three components of the alternating magnetic field along predefined measuring lines in the study area. Here we can show the first results that we shall continue during some cycles of monitoring. The second part of our work was linked with mapping the massif structure inside the oasis City, where only using our device we could construct the geoelectrical sections for 5 profiles and show the real structure of the water volume and its complicated structure up to 200 meters depth recording the values of real not apparent resistivity. The analytical treatments provided good information about the structure of the rock massive and its rank of degradation, the lateral distribution of the geotechnical heterogeneity, and finally a conclusive outcome about foundation stability. We can conclude that the general dynamic state close to the destruction level within the investigation areas is getting worse over the time; this is reflected in the crack's densities and positions, also on the changes in the lateral distribution of geoelectrical heterogeneity as an indicator of the saturation of the surface rock in the study area with water [1,2]. References 1. Magdy A. Atya, Olga A. Hachay, Mamdouh M. Soliman, Oleg Y. Khachay, Ahmed B. Khalill, Mahmoud Gaballah, Fathy F.Shaaban and Ibrahim A.El. Hemali. CSEM imaging of the near surface dynamics and its impact for foundation stability at quarter 27,15-th of May City, Helwan, Egypt. // Earth sciences research journal, 2010,Vol.14, N1, p.76-87. 2. Magdy A. Atya, Olga A. Hachay, Oleg Y. Khachay, El. Said A. Defining the geotechnical parameters of the medium with use of electromagnetic monitoring data with a control source for fixed frequencies. // Ural geophysical bulletin. 2014,№2,p.4-12.

Dissemination of the Phasor Method in Electrical Engineering in China

ERIC Educational Resources Information Center

Zhang, Liangliang; Lei, Yinzhao

2014-01-01

Synchrophasors, widely used in the monitoring and analysis of power systems, evolved from the phasor method presented by Charles Proteus Steinmetz in 1893. The phasor method is a mathematical method for solving linear sinusoidal steady-state circuits and time-varying electromagnetic fields. This paper traces the history and diffusion of the phasor…

Implementation of Networking-by-Touch to Small Unit, Network-Enabled Operations

DTIC Science & Technology

2010-09-01

Monitoring – Telemanipulation ............... 54  5.  Entertainment and Educational Applications...................... 55  6.  Tactile Displays Embedded...military situational awareness systems, text and graphics applications, medical applications, entertainment and educational applications...25] ) Electromechanical transducer Electromagnetic field sensors Computer driver 21 Now, consider another simple scenario: John loves music

An accelerated gamma irradiation test of low dose rate for a single mode fiber

NASA Astrophysics Data System (ADS)

Chiou, Chung-An; Peng, Tz-Shiuan; Liu, Ren-Young

2017-09-01

Conventional single mode fiber (SMF), due to its electromagnetic interference immunity, light weight, physical flexibility and broad bandwidth for data transmission, has been well employed in space, such as optical communication [1], structural health monitoring of spacecraft [2], and attitude determining applications, e.g. interferometric fiber optic gyroscope (IFOG).

Development of a new noninvasive method to determine the integrity of bone in vivo

NASA Technical Reports Server (NTRS)

Saha, S.

1980-01-01

An electromagnetic sensor for monitoring elastic waves in bone was developed. It does not require the use of traction pins and the output is not affected by soft tissue properties, a difficulty commonly encountered when using ultrasonic and vibration methods to determine in vivo properties of bone.

Multi-Phenomenology Explosion Monitoring (Multi-PEM). Signal Detection. Research to target smaller sources for tomorrow’s missions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carmichael, Joshua Daniel

2015-12-12

This a guide on how to detect and identify explosions from various sources. For example, nuclear explosions produce acoustic, optical, and EMP outputs. Each signal can be buried in noise, but fusing detection statistics from seismic, acoustic, and electromagnetic signals results in clear detection otherwise unobtainable.

Conflict monitoring and adjustment in the task-switching paradigm under different memory load conditions: an ERP/sLORETA analysis.

PubMed

Deng, Yuqin; Wang, Yan; Ding, Xiaoqian; Tang, Yi-Yuan

2015-02-11

The aim of the present study was to examine electrophysiological and behavioral changes caused by different memory loads in a task-switching paradigm. A total of 31 healthy individuals were subjected to a task, in which the stimulus-response reversal paradigm was combined with the task-switching paradigm. The event-related potentials were recorded and the N2 component, an index of conflict processing, was measured. In addition, the neural sources of N2 were further analyzed by standardized low-resolution brain electromagnetic tomography. The event-related potential results showed that high memory load triggered a higher N2 mean amplitude. Moreover, the standardized low-resolution brain electromagnetic tomography data showed that high memory load caused an increase in current densities at the anterior cingulate cortex and the prefrontal cortex in the task-switching paradigm. In summary, our findings provide electrophysiological evidence to interpret possible influences of memory loads on conflict monitoring and modulation during the task switching. These results imply that the working memory load overrules the influence of task-switching performance on the intensification of cognitive control.

High Frequency Electromagnetic Impedance Measurements for Characterization, Monitoring and Verification Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ki Ha; Becker, Alex; Framgos, William

1999-06-01

Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high-resolution imaging, accurate measurements are necessary so the field data can bemore » mapped into the space of the subsurface parameters. We are developing a non-invasive method for accurately imaging the electrical conductivity and dielectric permittivity of the shallow subsurface using the plane wave impedance approach. Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques.« less

High-Frequency Electromagnetic Impedance Measurements for Characterization, Monitoring and Verification Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ki Ha; Becker, Alex; Tseng, Hung-Wen

2002-11-20

Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic (EM) measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high-resolution imaging, accurate measurements are necessary so the field data canmore » be mapped into the space of the subsurface parameters. We are developing a non-invasive method for accurately mapping the electrical conductivity and dielectric permittivity of the shallow subsurface using the EM impedance approach (Frangos, 2001; Lee and Becker, 2001; Song et al., 2002). Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques.« less

High-Frequency Electromagnetic Impedance Measurements for Characterization, Monitoring, and Verification Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ki Ha; Becker, Alex

2000-06-01

Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high-resolution imaging, accurate measurements are necessary so the field data can bemore » mapped into the space of the subsurface parameters. We are developing a non-invasive method for accurately imaging the electrical conductivity and dielectric permittivity of the shallow subsurface using the plane wave impedance approach (Song et al., 1997). Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques.« less

High-Frequency Electromagnetic Impedance Measurements for Characterization, Monitoring and Verification Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ki Ha; Becker, Alex; Tseng, Hung-Wen

2001-06-10

Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic (EM) measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high-resolution imaging, accurate measurements are necessary so the field data canmore » be mapped into the space of the subsurface parameters. We are developing a non-invasive method for accurately mapping the electrical conductivity and dielectric permittivity of the shallow subsurface using the EM impedance approach (Frangos, 2001; Lee and Becker, 2001). Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques.« less

Design of Remote Monitoring System of Irrigation based on GSM and ZigBee Technology

NASA Astrophysics Data System (ADS)

Xiao xi, Zheng; Fang, Zhao; Shuaifei, Shao

2018-03-01

To solve the problems of low level of irrigation and waste of water resources, a remote monitoring system for farmland irrigation based on GSM communication technology and ZigBee technology was designed. The system is composed of sensors, GSM communication module, ZigBee module, host computer, valve and so on. The system detects and closes the pump and the electromagnetic valve according to the need of the system, and transmits the monitoring information to the host computer or the user’s Mobile phone through the GSM communication network. Experiments show that the system has low power consumption, friendly man-machine interface, convenient and simple. It can monitor agricultural environment remotely and control related irrigation equipment at any time and place, and can better meet the needs of remote monitoring of farmland irrigation.

Use of Permanent Magnets in Electromagnetic Facilities for the Treatment of Aluminum Alloys

NASA Astrophysics Data System (ADS)

Beinerts, Toms; Bojarevičs, Andris; Bucenieks, Imants; Gelfgat, Yuri; Kaldre, Imants

2016-06-01

The possibility of applying the electromagnetic induction pump with permanent magnets for the transportation and stirring of aluminum melts in metallurgical furnaces is investigated. The electromagnetic and hydraulic characteristics of the pump have been investigated theoretically and experimentally with regard to its position in the furnace. The results of the experiments performed with a model in a eutectic InGaSn melt are in good agreement with the calculation data. Extrapolation of the experimental results on the physical characteristics of aluminum melts allows recommending such pumps for contactless control of motion and heat/mass transfer in aluminum melts in different technological processes. A high temperature and the aggressive properties of aluminum alloys make it complicated to use different mechanical devices to solve technological problems, such as liquid metal transportation, dosing, stirring, etc. In this case, any device units or elements moving in or contacting with the melt suffer from corrosion polluting the melt. Therefore, of more importance and topicality are contactless electromagnetic methods for processing of molten metals.

Interaction of electromagnetic and acoustic waves in a stochastic atmosphere

NASA Technical Reports Server (NTRS)

Bhatnagar, N.; Peterson, A. M.

1979-01-01

In the Stanford radio acoustic sounding system (RASS) an electromagnetic signal is made to scatter from a moving acoustic pulse train. Under a Bragg-scatter condition maximum electromagnetic scattering occurs. The scattered radio signal contains temperature and wind information as a function of the acoustic-pulse position. In this investigation RASS performance is assessed in an atmosphere characterized by the presence of turbulence and mean atmospheric parameters. The only assumption made is that the electromagnetic wave is not affected by stochastic perturbations in the atmosphere. It is concluded that the received radio signal depends strongly on the intensity of turbulence for altitudes of the acoustic pulse greater than the coherence length of propagation. The effect of mean vertical wind and mean temperature on the strength of the received signal is also demonstrated to be insignificant. Mean horizontal winds, however, shift the focus of the reflected electromagnetic energy from its origin, resulting in a decrease in received signal level when a monostatic radio-frequency (RF) system is used. For a bistatic radar configuration with space diversified receiving antennas, the shifting of the acoustic pulse makes possible the remote measurement of the horizontal wind component.

Semiannual Status Report. [excitation of electromagnetic waves in the whistler frequency range

NASA Technical Reports Server (NTRS)

1994-01-01

During the last six months, we have continued our study of the excitation of electromagnetic waves in the whistler frequency range and the role that these waves will play in the acceleration of electrons and ions in the auroral region. A paper entitled 'Electron Beam Excitation of Upstream Waves in the Whistler Mode Frequency Range' was listed in the Journal of Geophysical Research. In this paper, we have shown that an anisotropic electron beam (or gyrating electron beam) is capable of generating both left-hand and right-hand polarized electromagnetic waves in the whistler frequency range. Since right-hand polarized electromagnetic waves can interact with background electrons and left-hand polarized waves can interact with background ions through cyclotron resonance, it is possible that these beam generated left-hand and right-hand polarized electromagnetic waves can accelerate either ions or electrons (or both), depending on the physical parameters under consideration. We are currently carrying out a comprehensive study of the electromagnetic whistler and lower hybrid like waves observed in the auroral zone using both wave and particle data. Our first task is to identify these wave modes and compare it with particle observations. Using both the DE-1 particle and wave measurements, we can positively identify those electromagnetics lower hybrid like waves as fast magnetosonic waves and the upper cutoff of these waves is the local lower hybrid frequency. From the upper cutoff of the frequency spectrum, one can infer the particle density and the result is in very good agreement with the particle data. Since these electromagnetic lower hybrid like waves can have frequencies extended down to the local ion cyclotron frequency, it practically confirms that they are not whistler waves.

Technique for Radiometer and Antenna Array Calibration - TRAAC

NASA Technical Reports Server (NTRS)

Meyer, Paul; Sims, William; Varnavas, Kosta; McCracken, Jeff; Srinivasan, Karthik; Limaye, Ashutosh; Laymon, Charles; Richeson. James

2012-01-01

Highly sensitive receivers are used to detect minute amounts of emitted electromagnetic energy. Calibration of these receivers is vital to the accuracy of the measurements. Traditional calibration techniques depend on calibration reference internal to the receivers as reference for the calibration of the observed electromagnetic energy. Such methods can only calibrate errors in measurement introduced by the receiver only. The disadvantage of these existing methods is that they cannot account for errors introduced by devices, such as antennas, used for capturing electromagnetic radiation. This severely limits the types of antennas that can be used to make measurements with a high degree of accuracy. Complex antenna systems, such as electronically steerable antennas (also known as phased arrays), while offering potentially significant advantages, suffer from a lack of a reliable and accurate calibration technique. The proximity of antenna elements in an array results in interaction between the electromagnetic fields radiated (or received) by the individual elements. This phenomenon is called mutual coupling. The new calibration method uses a known noise source as a calibration load to determine the instantaneous characteristics of the antenna. The noise source is emitted from one element of the antenna array and received by all the other elements due to mutual coupling. This received noise is used as a calibration standard to monitor the stability of the antenna electronics.

Probing extra dimension through gravitational wave observations of compact binaries and their electromagnetic counterparts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Hao; Gu, Bao-Min; Wang, Yong-Qiang

The future gravitational wave (GW) observations of compact binaries and their possible electromagnetic counterparts may be used to probe the nature of the extra dimension. It is widely accepted that gravitons and photons are the only two completely confirmed objects that can travel along null geodesics in our four-dimensional space-time. However, if there exist extra dimensions and only GWs can propagate freely in the bulk, the causal propagations of GWs and electromagnetic waves (EMWs) are in general different. In this paper, we study null geodesics of GWs and EMWs in a five-dimensional anti-de Sitter space-time in the presence of themore » curvature of the universe. We show that for general cases the horizon radius of GW is longer than EMW within equal time. Taking the GW150914 event detected by the Advanced Laser Interferometer Gravitational-Wave Observatory and the X-ray event detected by the Fermi Gamma-ray Burst Monitor as an example, we study how the curvature k and the constant curvature radius l affect the horizon radii of GW and EMW in the de Sitter and Einstein-de Sitter models of the universe. This provides an alternative method for probing extra dimension through future GW observations of compact binaries and their electromagnetic counterparts.« less

Fiber-Optic Distribution Of Pulsed Power To Multiple Sensors

NASA Technical Reports Server (NTRS)

Kirkham, Harold

1996-01-01

Optoelectronic systems designed according to time-sharing scheme distribute optical power to multiple integrated-circuit-based sensors in fiber-optic networks. Networks combine flexibility of electronic sensing circuits with advantage of electrical isolation afforded by use of optical fibers instead of electrical conductors to transmit both signals and power. Fiber optics resist corrosion and immune to electromagnetic interference. Sensor networks of this type useful in variety of applications; for example, in monitoring strains in aircraft, buildings, and bridges, and in monitoring and controlling shapes of flexible structures.

In-situ measurement of processing properties during fabrication in a production tool

NASA Technical Reports Server (NTRS)

Kranbuehl, D. E.; Haverty, P.; Hoff, M.; Loos, A. C.

1988-01-01

Progress is reported on the use of frequency-dependent electromagnetic measurements (FDEMs) as a single, convenient technique for continuous in situ monitoring of polyester cure during fabrication in a laboratory and manufacturing environment. Preliminary FDEM sensor and modeling work using the Loss-Springer model in order to develop an intelligent closed-loop, sensor-controlled cure process is described. FDEMs using impedance bridges in the Hz to MHz region is found to be ideal for automatically monitoring polyester processing properties continuously throughout the cure cycle.

Monitoring processing properties of high performance thermoplastics using frequency dependent electromagnetic sensing

NASA Technical Reports Server (NTRS)

Kranbuehl, D. E.; Delos, S. E.; Hoff, M. S.; Weller, L. W.; Haverty, P. D.

1987-01-01

An in situ NDE dielectric impedance measurement method has been developed for ascertaining the cure processing properties of high temperature advanced thermoplastic and thermosetting resins, using continuous frequency-dependent measurements and analyses of complex permittivity over 9 orders of magnitude and 6 decades of frequency at temperatures up to 400 C. Both ionic and Debye-like dipolar relaxation processes are monitored. Attention is given to LARC-TPI, PEEK, and poly(arylene ether) resins' viscosity, glass transition temperature, recrystallization, and residual solvent content and evolution properties.

Electromagnetic Monitoring of Hydraulic Fracturing: Relationship to Permeability, Seismicity, and Stress

NASA Astrophysics Data System (ADS)

Thiel, Stephan

2017-09-01

Hydraulic fracking is a geoengineering application designed to enhance subsurface permeability to maximize fluid and gas flow. Fracking is commonly used in enhanced geothermal systems (EGS), tight shale gas, and coal seam gas (CSG) plays and in CO_2 storage scenarios. Common monitoring methods include microseismics and mapping small earthquakes with great resolution associated with fracture opening at reservoir depth. Recently, electromagnetic (EM) methods have been employed in the field to provide an alternative way of direct detection of fluids as they are pumped in the ground. Surface magnetotelluric (MT) measurements across EGS show subtle yet detectable changes during fracking derived from time-lapse MT deployments. Changes are directional and are predominantly aligned with current stress field, dictating preferential fracture orientation, supported by microseismic monitoring of frack-related earthquakes. Modeling studies prior to the injection are crucial for survey design and feasibility of monitoring fracks. In particular, knowledge of sediment thickness plays a fundamental role in resolving subtle changes. Numerical forward modeling studies clearly favor some form of downhole measurement to enhance sensitivity; however, these have yet to be conclusively demonstrated in the field. Nevertheless, real surface-based monitoring examples do not necessarily replicate the expected magnitude of change derived from forward modeling and are larger than expected in some cases from EGS and CSG systems. It appears the injected fluid volume alone cannot account for the surface change in resistivity, but connectedness of pore space is also significantly enhanced and nonlinear. Recent numerical studies emphasize the importance of percolation threshold of the fracture network on both electrical resistivity and permeability, which may play an important role in accounting for temporal changes in surface EM measurements during hydraulic fracking.

Multistage Magnetic Separator of Cells and Proteins

NASA Technical Reports Server (NTRS)

Barton, Ken; Ainsworth, Mark; Daily, Bruce; Dunn, Scott; Metz, Bill; Vellinger, John; Taylor, Brock; Meador, Bruce

2005-01-01

The multistage electromagnetic separator for purifying cells and magnetic particles (MAGSEP) is a laboratory apparatus for separating and/or purifying particles (especially biological cells) on the basis of their magnetic susceptibility and magnetophoretic mobility. Whereas a typical prior apparatus based on similar principles offers only a single stage of separation, the MAGSEP, as its full name indicates, offers multiple stages of separation; this makes it possible to refine a sample population of particles to a higher level of purity or to categorize multiple portions of the sample on the basis of magnetic susceptibility and/or magnetophoretic mobility. The MAGSEP includes a processing unit and an electronic unit coupled to a personal computer. The processing unit includes upper and lower plates, a plate-rotation system, an electromagnet, an electromagnet-translation system, and a capture-magnet assembly. The plates are bolted together through a roller bearing that allows the plates to rotate with respect to each other. An interface between the plates acts as a seal for separating fluids. A lower cuvette can be aligned with as many as 15 upper cuvette stations for fraction collection during processing. A two-phase stepping motor drives the rotation system, causing the upper plate to rotate for the collection of each fraction of the sample material. The electromagnet generates a magnetic field across the lower cuvette, while the translation system translates the electromagnet upward along the lower cuvette. The current supplied to the electromagnet, and thus the magnetic flux density at the pole face of the electromagnet, can be set at a programmed value between 0 and 1,400 gauss (0.14 T). The rate of translation can be programmed between 5 and 2,000 m/s so as to align all sample particles in the same position in the cuvette. The capture magnet can be a permanent magnet. It is mounted on an arm connected to a stepping motor. The stepping motor rotates the arm to position the capture magnet above the upper cuvette into which a fraction of the sample is collected. The electronic unit includes a power switch, power-supply circuitry that accepts 110-Vac input power, an RS-232 interface, and status lights. The personal computer runs the MAGSEP software and controls the operation of the MAGSEP through the RS-232 interface. The status of the power, the translating electromagnet, the capture magnet, and the rotation of the upper plate are indicated in a graphical user interface on the computer screen.

A review of fiber-optic corrosion sensor in civil engineering

NASA Astrophysics Data System (ADS)

Luo, Dong; Li, Junnan; Li, Yuanyuan

2018-05-01

Fiber-optical corrosion sensor (FOCS) is the research hotspot of corrosion monitoring sensor in recent years. It has the advantages of lightness, simplicity, anti-electromagnetic interference and distributed measurement, so it has an attractive application prospect. In this paper, the mechanism of metal corrosion is introduced. Several common methods for detecting optical fiber corrosion sensors are presented, and the latest progress of optical fiber corrosion sensors in recent years is described. We need to design a set of sensor devices that can directly monitor the corrosion of reinforcing steel bars directly, and propose a method of time dependent reliability assessment based on monitoring data, so as to form a complete research path.

Controversies related to electromagnetic field exposure on peripheral nerves.

PubMed

Say, Ferhat; Altunkaynak, Berrin Zuhal; Coşkun, Sina; Deniz, Ömür Gülsüm; Yıldız, Çağrı; Altun, Gamze; Kaplan, Arife Ahsen; Kaya, Sefa Ersan; Pişkin, Ahmet

2016-09-01

Electromagnetic field (EMF) is a pervasive environmental presence in modern society. In recent years, mobile phone usage has increased rapidly throughout the world. As mobile phones are generally held close to the head while talking, studies have mostly focused on the central and peripheral nervous system. There is a need for further research to ascertain the real effect of EMF exposure on the nervous system. Several studies have clearly demonstrated that EMF emitted by cell phones could affect the systems of the body as well as functions. However, the adverse effects of EMF emitted by mobile phones on the peripheral nerves are still controversial. Therefore, this review summarizes current knowledge on the possible positive or negative effects of electromagnetic field on peripheral nerves. Copyright © 2015 Elsevier B.V. All rights reserved.

Radiofrequency Electromagnetic Field Map of Timisoara

NASA Astrophysics Data System (ADS)

Stefu, N.; Solyom, I.; Arama, A.

2015-12-01

There are many electromagnetic field (EMF) sources nowadays acting simultaneously, especially in urban areas, making the theoretical estimation of electromagnetic power at ground level very difficult. This paper reports on EMF maps built with measurements collected in Timisoara, at various radiofrequencies. A grid of 15×15 squares was built (approximate resolution 400m x 400m) and measurements of the average and maximum values of the electric field E, magnetic field H and total power density S at 0.9, 1.8 and 2.4 GHz were collected in every node of the grid. Positions of the nodes in terms of latitude and longitude were also collected. Maps were built presenting the spatial distribution of the measured quantities over Timisoara. Potential influences of EMF on public health are discussed.

Initial Results from Awesome VLF Receiver Installed in Ecuador

NASA Astrophysics Data System (ADS)

Lopez, Ericson

2012-07-01

In this work we present the first results that we have derived from analysis of data obtained using the Atmospheric Weather Electromagnetic System for Observation Modeling and Education (Awesome) VLF receiver, designed and developed by Stanford University, USA. The receiver was installed under inter-institutional cooperation in the emerging Space Science division of the Quito Astronomical Observatory, and it is working properly since 2010. We have describe the performance characteristic of the Awesome system and the importance of having receivers at equator for monitoring the ionosphere and magnetosphere, recepting extremely low frequencies (ELF;30-3000 Hz) and very low frequencies (VLF; 3-30 KHz) electromagnetic waves, in order to better understanding the physical processes which take place in these media.

Non-ionizing radiofrequency electromagnetic waves traversing the head can be used to detect cerebrovascular autoregulation responses

NASA Astrophysics Data System (ADS)

Oziel, M.; Hjouj, M.; Gonzalez, C. A.; Lavee, J.; Rubinsky, B.

2016-02-01

Monitoring changes in non-ionizing radiofrequency electromagnetic waves as they traverse the brain can detect the effects of stimuli employed in cerebrovascular autoregulation (CVA) tests on the brain, without contact and in real time. CVA is a physiological phenomenon of importance to health, used for diagnosis of a number of diseases of the brain with a vascular component. The technology described here is being developed for use in diagnosis of injuries and diseases of the brain in rural and economically underdeveloped parts of the world. A group of nine subjects participated in this pilot clinical evaluation of the technology. Substantial research remains to be done on correlating the measurements with physiology and anatomy.

Microgravity

NASA Image and Video Library

1994-07-10

TEMPUS, an electromagnetic levitation facility that allows containerless processing of metallic samples in microgravity, first flew on the IML-2 Spacelab mission. The principle of electromagnetic levitation is used commonly in ground-based experiments to melt and then cool metallic melts below their freezing points without solidification occurring. The TEMPUS operation is controlled by its own microprocessor system; although commands may be sent remotely from the ground and real time adjustments may be made by the crew. Two video cameras, a two-color pyrometer for measuring sample temperatures, and a fast infrared detector for monitoring solidification spikes, will be mounted to the process chamber to facilitate observation and analysis. In addition, a dedicated high-resolution video camera can be attached to the TEMPUS to measure the sample volume precisely.

Verification of the effects of Schumann frequency range electromagnetic fields on the human cardiovascular system

NASA Astrophysics Data System (ADS)

Tuzhilkin, D. A.; Borodin, A. S.

2017-11-01

The results of the study of variations in the electromagnetic background parameters of the Schumann resonator frequency range and the variability indices of the human heart period during its free activity are presented on the basis of 24-hour synchronous monitoring data. It is shown that the integral evaluation of the conjugacy of the heart rate variability indices from the Schumann resonance parameters is extremely weak. In this case, the differential evaluation of this dependence with separation into characteristic time intervals of the day, characterized by different motor activity of the subjects, becomes significantly higher. The number of volunteers whose conjugacy is characterized by a strong correlation in some cases reaches 35 percent of the sample.

Investigation of the cosmic-ray energy spectrum and anisotropy during the solar proton events of June 11 and 15, 1991

NASA Astrophysics Data System (ADS)

Kravtsova, M. V.; Sdobnov, V. E.

2015-09-01

Using data from a worldwide network of neutron monitors, we have investigated the cosmicray (CR) energy spectra and anisotropy during the CR increases attributable to the solar events of June 11 and 15, 1991, by the spectrographic global survey method. By jointly analyzing ground-based and satellite measurements, we have determined the parameters of the CR rigidity spectrum reflecting the electromagnetic characteristics of the heliospheric fields in each hour of observations within the framework of the model of CR modulation by regular heliospheric electromagnetic fields. The CR spectra and relative CR intensity variations in the solar—ecliptic geocentric coordinate system are presented at specific times of these events.

A spaceborne receiver for measuring electromagnetic field intensity

NASA Technical Reports Server (NTRS)

Reich, B. W.; Van Dusen, M. R.; Habib, E. J.

1973-01-01

Description of a very accurately controlled receiver for monitoring the electromagnetic radiations in both existing and projected space communication bands. Based on analysis of the existing and projected space communication bands, 108 to 174 MHz, 240 to 478 MHz, and 1535 to 1665 MHz were covered. The receiver achieves accurate control via a digitally tuned synthesizer and a wide range of digital control including frequency band coverage and gain control selection. Digital memory was provided to store 16 separate digital command instructions which can be programmed via a command data link. The receiver provides for transmission to the ground of both a predetection signal and signals in digital format, which in turn, were provided by sampling and analog-to-digital conversions.

An electromagnetic/electrostatic dual cathode system for electron beam instruments

NASA Technical Reports Server (NTRS)

Bradley, J. G.; Conley, J. M.; Wittry, D. B.; Albee, A. L.

1986-01-01

A method of providing cathode redundancy which consists of two fixed cathodes and uses electromagnetic and/or electrostatic fields to direct the electron beam to the electron optical axis is presented, with application to the cathode system of the Scanning Electron Microscope and Particle Analyzer proposed for NASA's Mariner Mark II Comet Rendezvous/Asteroid Flyby projected for the 1990s. The symmetric double deflection system chosen has the optical property that the image of the effective electron source is formed above the magnet assembly near the apparent position of the effective source, and it makes the transverse positions of the electron sources independent of the electron beam energy. Good performance of the system is found, with the sample imaging resolution being the same as for the single-axis cathode.

Dual-latching solenoid-actuated valve assembly

NASA Technical Reports Server (NTRS)

Brudnicki, Myron J. (Inventor); Yang, Jeff (Inventor)

1994-01-01

A tube-type shutoff valve is electrically positioned to its open or closed position by a concentric electromagnetic solenoid. The valve is dual latching in that the armature of the solenoid maintains the sliding tube of the valve in an open or closed position by means of permanent magnets which are effective when current is not supplied to the solenoid. The valve may also be actuated manually.

The use of a robotic tibial rotation device and an electromagnetic tracking system to accurately reproduce the clinical dial test.

PubMed

Stinton, S K; Siebold, R; Freedberg, H; Jacobs, C; Branch, T P

2016-03-01

The purpose of this study was to: (1) determine whether a robotic tibial rotation device and an electromagnetic tracking system could accurately reproduce the clinical dial test at 30° of knee flexion; (2) compare rotation data captured at the footplates of the robotic device to tibial rotation data measured using an electromagnetic sensor on the proximal tibia. Thirty-two unilateral ACL-reconstructed patients were examined using a robotic tibial rotation device that mimicked the dial test. The data reported in this study is only from the healthy legs of these patients. Torque was applied through footplates and was measured using servomotors. Lower leg motion was measured at the foot using the motors. Tibial motion was also measured through an electromagnetic tracking system and a sensor on the proximal tibia. Load-deformation curves representing rotational motion of the foot and tibia were compared using Pearson's correlation coefficients. Off-axis motions including medial-lateral translation and anterior-posterior translation were also measured using the electromagnetic system. The robotic device and electromagnetic system were able to provide axial rotation data and translational data for the tibia during the dial test. Motion measured at the foot was not correlated to motion of the tibial tubercle in internal rotation or in external rotation. The position of the tibial tubercle was 26.9° ± 11.6° more internally rotated than the foot at torque 0 Nm. Medial-lateral translation and anterior-posterior translation were combined to show the path of the tubercle in the coronal plane during tibial rotation. The information captured during a manual dial test includes both rotation of the tibia and proximal tibia translation. All of this information can be captured using a robotic tibial axial rotation device with an electromagnetic tracking system. The pathway of the tibial tubercle during tibial axial rotation can provide additional information about knee instability without relying on side-to-side comparison between knees. The translation of the proximal tibia is important information that must be considered in addition to axial rotation of the tibia when performing a dial test whether done manually or with a robotic device. Instrumented foot position cannot provide the same information. IV.

Numerical analysis of multicomponent responses of surface-hole transient electromagnetic method

NASA Astrophysics Data System (ADS)

Meng, Qing-Xin; Hu, Xiang-Yun; Pan, He-Ping; Zhou, Feng

2017-03-01

We calculate the multicomponent responses of surface-hole transient electromagnetic method. The methods and models are unsuitable as geoelectric models of conductive surrounding rocks because they are based on regular local targets. We also propose a calculation and analysis scheme based on numerical simulations of the subsurface transient electromagnetic fields. In the modeling of the electromagnetic fields, the forward modeling simulations are performed by using the finite-difference time-domain method and the discrete image method, which combines the Gaver-Stehfest inverse Laplace transform with the Prony method to solve the initial electromagnetic fields. The precision in the iterative computations is ensured by using the transmission boundary conditions. For the response analysis, we customize geoelectric models consisting of near-borehole targets and conductive wall rocks and implement forward modeling simulations. The observed electric fields are converted into induced electromotive force responses using multicomponent observation devices. By comparing the transient electric fields and multicomponent responses under different conditions, we suggest that the multicomponent-induced electromotive force responses are related to the horizontal and vertical gradient variations of the transient electric field at different times. The characteristics of the response are determined by the varying the subsurface transient electromagnetic fields, i.e., diffusion, attenuation and distortion, under different conditions as well as the electromagnetic fields at the observation positions. The calculation and analysis scheme of the response consider the surrounding rocks and the anomalous field of the local targets. It therefore can account for the geological data better than conventional transient field response analysis of local targets.

Verification of the Microgravity Active Vibration Isolation System based on Parabolic Flight

NASA Astrophysics Data System (ADS)

Zhang, Yong-kang; Dong, Wen-bo; Liu, Wei; Li, Zong-feng; Lv, Shi-meng; Sang, Xiao-ru; Yang, Yang

2017-12-01

The Microgravity active vibration isolation system (MAIS) is a device to reduce on-orbit vibration and to provide a lower gravity level for certain scientific experiments. MAIS system is made up of a stator and a floater, the stator is fixed on the spacecraft, and the floater is suspended by electromagnetic force so as to reduce the vibration from the stator. The system has 3 position sensors, 3 accelerometers, 8 Lorentz actuators, signal processing circuits and a central controller embedded in the operating software and control algorithms. For the experiments on parabolic flights, a laptop is added to MAIS for monitoring and operation, and a power module is for electric power converting. The principle of MAIS is as follows: the system samples the vibration acceleration of the floater from accelerometers, measures the displacement between stator and floater from position sensitive detectors, and computes Lorentz force current for each actuator so as to eliminate the vibration of the scientific payload, and meanwhile to avoid crashing between the stator and the floater. This is a motion control technic in 6 degrees of freedom (6-DOF) and its function could only be verified in a microgravity environment. Thanks for DLR and Novespace, we get a chance to take the DLR 27th parabolic flight campaign to make experiments to verify the 6-DOF control technic. The experiment results validate that the 6-DOF motion control technique is effective, and vibration isolation performance perfectly matches what we expected based on theoretical analysis and simulation. The MAIS has been planned on Chinese manned spacecraft for many microgravity scientific experiments, and the verification on parabolic flights is very important for its following mission. Additionally, we also test some additional function by microgravity electromagnetic suspension, such as automatic catching and locking and working in fault mode. The parabolic flight produces much useful data for these experiments.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bunch, Kyle J.; Williams, Laura S.; Jones, Anthony M.

The 2010 ratification of the New START Treaty has been widely regarded as a noteworthy national security achievement for both the Obama administration and the Medvedev-Putin regime, but deeper cuts are envisioned under future arms control regimes. Future verification needs will include monitoring the storage of warhead components and fissile materials and verifying dismantlement of warheads, pits, secondaries, and other materials. From both the diplomatic and technical perspectives, verification under future arms control regimes will pose new challenges. Since acceptable verification technology must protect sensitive design information and attributes, non-nuclear non-sensitive signatures may provide a significant verification tool without themore » use of additional information barriers. The use of electromagnetic signatures to monitor nuclear material storage containers is a promising technology with the potential to fulfill these challenging requirements. Research performed at Pacific Northwest National Laboratory (PNNL) has demonstrated that low frequency electromagnetic signatures of sealed metallic containers can be used to confirm the presence of specific components on a “yes/no” basis without revealing classified information. Arms control inspectors might use this technique to verify the presence or absence of monitored items, including both nuclear and non-nuclear materials. Although additional research is needed to study signature aspects such as uniqueness and investigate container-specific scenarios, the technique potentially offers a rapid and cost-effective tool to verify reduction and dismantlement of U.S. and Russian nuclear weapons.« less

Exposure to electromagnetic fields during pregnancy with emphasis on electrically heated beds: association with birthweight and intrauterine growth retardation.

PubMed

Bracken, M B; Belanger, K; Hellenbrand, K; Dlugosz, L; Holford, T R; McSharry, J E; Addesso, K; Leaderer, B

1995-05-01

Several animal and human studies indicate that fetal growth may be retarded following exposure to electromagnetic fields (EMF). We conducted a prospective study (N = 2,967) to evaluate the relation of birthweight and fetal growth retardation with use of electrically heated beds (electric blankets and heated water beds) during pregnancy. A "nested" study design allowed monitoring of exposure at different stages of pregnancy using both direct and indirect methods. We assessed EMF exposure using personal monitors, home measurement, video display terminal use, and wire code. Exposure to EMF during pregnancy, either at conception, at < or = 16 weeks, or in the third trimester, showed no important relation to risk of low birth-weight or fetal growth retardation. This result was the same whether we used subjective measures of exposure or direct measurement. Use of video display terminals at home or work, exposure to > or = 2.0-milligauss fields as measured by home or personal monitors, and home wire code were unrelated to the reproductive outcomes studied. A time-weighted analysis of electric bed use, which accounted for strength of EMF exposure and hours of use, also showed evidence of no meaningful increase in risk. None of the exposure measures showed a dose response relation to risk. We conclude that risk of low birth-weight and intrauterine growth retardation is not increased after electrically heated bed use during pregnancy.

The Effect of Anatomic Factors on Tongue Position Variability during Consonants

ERIC Educational Resources Information Center

Rudy, Krista; Yunusova, Yana

2013-01-01

Purpose: This study sought to investigate the effect of palate morphology and anthropometric measures of the head on positional variability of the tongue during consonants. Method: An electromagnetic tracking system was used to record tongue movements of 21 adults. Each talker produced a series of symmetrical VCV syllables containing one of the…

Applying TM-polarization geoelectric exploration for study of low-contrast three-dimensional targets

NASA Astrophysics Data System (ADS)

Zlobinskiy, Arkadiy; Mogilatov, Vladimir; Shishmarev, Roman

2018-03-01

With using new field and theoretical data, it has been shown that applying the electromagnetic field of transverse magnetic (TM) polarization will give new opportunities for electrical prospecting by the method of transient processes. Only applying a pure field of the TM polarization permits poor three-dimensional objects (required metalliferous deposits) to be revealed in a host horizontally-layered medium. This position has good theoretical grounds. There is given the description of the transient electromagnetic method, that uses only the TM polarization field. The pure TM mode is excited by a special source, which is termed as a circular electric dipole (CED). The results of three-dimensional simulation (by the method of finite elements) are discussed for three real geological situations for which applying electromagnetic fields of transverse electric (TE) and transverse magnetic (TM) polarizations are compared. It has been shown that applying the TE mode gives no positive results, while applying the TM polarization field permits the problem to be tackled. Finally, the results of field works are offered, which showed inefficiency of application of the classical TEM method, whereas in contrast, applying the field of TM polarization makes it easy to identify the target.

The microwave radiometer spacecraft: A design study

NASA Technical Reports Server (NTRS)

Wright, R. L. (Editor)

1981-01-01

A large passive microwave radiometer spacecraft with near all weather capability of monitoring soil moisture for global crop forecasting was designed. The design, emphasizing large space structures technology, characterized the mission hardware at the conceptual level in sufficient detail to identify enabling and pacing technologies. Mission and spacecraft requirements, design and structural concepts, electromagnetic concepts, and control concepts are addressed.

ISTIMES project: status and outcomes

NASA Astrophysics Data System (ADS)

Cuomo, V.; Proto, M.; Soldovieri, F.

2012-04-01

ISTIMES is a project approved in the Seventh Framework Programme of the European Union under the Joint Call FP7-ICT-SEC-2007-1. It has a three years duration and will be completed within June 2012. According to the aims of the proposal, ISTIMES project has designed, assessed and developed a prototypical modular and scalable ICT-based system, exploiting distributed and local sensors, for non-destructive electromagnetic monitoring; the specific application field was the reliability and safety of critical transport infrastructures, even if the modularity of the ISTIMES approach has permitted to extend it successfully to other critical infrastructures as dams. The continuous and fruitful involvement of end users (as Italian Civil Protection) allowed to develop applications focused on users needs. ISTIMES couples current monitoring of infrastructures with a high situational awareness during crises management, providing updated and detailed real and near real time information about the infrastructure status to improve decision support for emergency and disasters stakeholders. The system exploits an open network architecture that can accommodate a wide range of heterogeneous sensors, static and mobile, and can be easily scaled up to allow the integration of additional sensors and interfaces with other networks. It relies on state-of-the-art electromagnetic sensors, enabling a networking of terrestrial sensors, supported by specific satellite and airborne measurements. The integration of electromagnetic technologies with new ICT information and telecommunications systems enables remotely controlled monitoring and surveillance at different temporal and spatial scales, providing indexes and images of the critical transport infrastructures. The project has exploited, assessed and improved many different non-invasive technologies based on electromagnetic sensing as: Optic Fiber Sensors, Synthetic Aperture; Radar (SAR) satellite platform; Hyperspectral Spectroscopy; Infrared Thermography; Ground Penetrating Radar; low-frequency Geophysical Techniques; ground based SAR and optical cameras for the assessment of the dynamical behaviour of the infrastructure. A great effort has been devoted to "transfer" these novel and state-of art technologies from the laboratory experience to actual on field applications by adapting/improving them and developing prototypes for the specific application domain of the monitoring of transport and critical infrastructures. Sensor synergy, data cross correlation and novel concepts of information fusion have permitted to carry out a multi-method, multi-resolution and multi-scale electromagnetic detection and monitoring of the infrastructure, including surface and subsurface aspects. The project has allowed to develop an ICT architecture based on web sensors and serviceoriented- technologies that comply with specific end-user requirements, including interoperability, economical convenience, exportability, efficiency and reliability. The efforts have focussed mainly to the creation of web based interfaces able to control "not standard" sensors, as the ones proposed in the project, and to the standardization necessary to have a full interoperability and modularity of the monitoring system. In addition, the system is able to provide a more easily accessible and transparent scheme for use by different end-users and to integrate the monitoring results and images with other kind of information such as GIS layer and historical datasets relating to the site. The ISTIMES system has been evaluated at two test sites and two test beds. At the two test sites of Montagnole rock-fall station (Chambery, France) and Hydrogeosite Laboratory (Potenza, Italy), the attention was posed to a thorough analysis of the performances of the in situ sensing techniques, by investigating, with good outcomes, also the possibility to correlate and have a synergy from the different sensors. In particular, it is worth noting that the experiment realized at Montagnole is unique, at least at European level, regarding both the high mechanical impact on a real scale elements of civil engineering structure, and also for the exploitation of all sensor techniques set up in a cooperative way. The effectiveness of the overall monitoring system has been assessed by the experiments at real test beds as Sihlhochstrasse bridge, a 1.5 km bridge representing one of the main entrance road to Zurich city (Switzerland), Varco Izzo railway tunnel and Musmeci motorway bridge located in the area of Potenza city in Basilicata region (Italy) affected by a high seismic risk. In particular, for the Musmeci bridge, the main entrance road to Potenza city and a masterpiece of architectural/civil engineering realized by Sergio Musmeci in 60' years, all the sensing technologies involved in the project have been exploited to perform a monitoring/diagnostics; the Musmeci bridge results have been correlated and tested also by the comparison with the sensors mostly used by civil engineers for this kind of infrastructures (Proto et al., 2010). Acknowledgment The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under Grant Agreement n. 225663.

Development of Self-Potential Tomography for Early Warning System of rainfall induced Landslides: Electro-kinetic Effects and Sandbox Experiments

NASA Astrophysics Data System (ADS)

Hattori, K.; Yamazaki, T.; Terajima, T.; Huang, Q.

2017-12-01

Electro-kinetic effects is one of the possible mechanism for ULF electromagnetic phenomena preceeding landlisdes and large earthquakes. To understand general tendencies of electromagnetic changes related to electro-kinetic effects, we struggle with the integrated research to clarify the coupling among hydrological, geotechnical, and electromagnetic changes. Our final goal is to understand the ULF elecromagnetic phenomena in order to develop a simple technology for earthquake monitoring/forecasting. So, in this paper, we first show the observed waveforms possibly related to the Boso slow slip events in 2003 and 2007 and indoor landslide experiments with artificial rainfall. Then, numerical computations on the self-potential variation by the simulated groundwater flow, and compare the results with those observed by laboratory experiments. In the result, the simulated self-potential variation is consistent with observed one. FInally, we developed self-potential tomography to estimate the ground water condition. And we also characterize the pressure from the self-potential data, and compare the result with observed pressure head that is measured by pore-pressure gauge and found that the inverted pressure head is consistent with observed one. In addition, we apply the self-potential data observed by the flume test. The estimated pressure head from observed self-potential data shows the consistency with observed pressure head. And estimated pressure head also show the characteristic distribution before the landslide occurred. These facts are highly suggestive in effectiveness of the self-potential tomography to monitor groundwater changes associated with landslide. The details will be given in our presentation.

Effect of Body Mass Index on Intrafraction Prostate Displacement Monitored by Real-Time Electromagnetic Tracking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butler, Wayne M., E-mail: wbutler@wheelinghospital.org; Wheeling Jesuit University, Wheeling, West Virginia; Morris, Mallory N.

2012-10-01

Purpose: To evaluate, using real-time monitoring of implanted radiofrequency transponders, the intrafraction prostate displacement of patients as a function of body mass index (BMI). Methods and Materials: The motions of Beacon radiofrequency transponders (Calypso Medical Technologies, Seattle, WA) implanted in the prostate glands of 66 men were monitored throughout the course of intensity modulated radiation therapy. Data were acquired at 10 Hz from setup to the end of treatment, but only the 1.7 million data points with a 'beam on' tag were used in the analysis. There were 21 obese patients, with BMI {>=}30 and 45 nonobese patients in themore » study. Results: Mean displacements were least in the left-right lateral direction (0.56 {+-} 0.24 mm) and approximately twice that magnitude in the superior-inferior and anterior-posterior directions. The net vector displacement was larger still, 1.95 {+-} 0.47 mm. Stratified by BMI cohort, the mean displacements per patient in the 3 Cartesian axes as well as the net vector for patients with BMI {>=}30 were slightly less (<0.2 mm) but not significantly different than the corresponding values for patients with lower BMIs. As a surrogate for the magnitude of oscillatory noise, the standard deviation for displacements in all measured planes showed no significant differences in the prostate positional variability between the lower and higher BMI groups. Histograms of prostate displacements showed a lower frequency of large displacements in obese patients, and there were no significant differences in short-term and long-term velocity distributions. Conclusions: After patients were positioned accurately using implanted radiofrequency transponders, the intrafractional displacements in the lateral, superior-inferior, and anterior-posterior directions as well as the net vector displacements were smaller, but not significantly so, for obese men than for those with lower BMI.« less

America's Stonehenge, (A.S.), Its "Window into the Past," Jung's "Reincarnations," and Problems Like "A Wonderful Mind" Are Associated With Time-recurret Natural Phenomena Monitored By Native Americans Impacting Religous Zealotry.

NASA Astrophysics Data System (ADS)

Alexander, Kimbereley E.; McLeod, Roger D.

2002-04-01

Phenomena detected at A.S. in North Salem, N.H. are associated with: positive ionic charges, inclement weather, periodicities that are daily, weekly, earth-moon related, but not with the full moon, seasonal annual and longer cyclicities, exceedingly faint lotus-blossom-blue light "tubes" traveling along electromagnetic field (EMF) lines, incorrect beliefs about reincarnation, and a multitude of aspects of schizophrenia as popularized in the movie "A Wonderful Mind". EgyptAir Flight 990, 10/99, documented approximately 90 seconds of the copilot's repeated phrase "I rely on God." Spiritual Gnostic, Cathar-Amerindian mistaken "reincarnations" and other esoteric mystical visions and unions, teenagers or other psychologically bizarre behaviors and all of the above are related to detectable or documented time variations of the EMF; Amerindians say schizoid behavior, supernatural beings, or advanced ideas are "Manitou" aspects of the Great Spirit, our EMF!

Influence of disorder on electromagnetically induced transparency in chiral waveguide quantum electrodynamics

NASA Astrophysics Data System (ADS)

Mirza, Imran M.; Schotland, John C.

2018-05-01

We study single photon transport in a one-dimensional disordered lattice of three-level atoms coupled to an optical waveguide. In particular, we study atoms of \\Lambda-type that are capable of exhibiting electromagnetically induced transparency (EIT) and separately consider disorder in the atomic positions and transition frequencies. We mainly address the question of how preferential emission into waveguide modes (chirality) can influence the formation of spatially localized states. Our work has relevance to experimental studies of cold atoms coupled to nanoscale waveguides and has possible applications to quantum communications.

Design and testing of an electromagnetic coupling

NASA Technical Reports Server (NTRS)

Anderson, William J.

1986-01-01

Hostile environments such as the hard vacuum of space, and exposure to water or caustic fluids have fostered the development of devices which allow mechanical rotary feed throughs with positive sealing without the use of conventional dynamic seals. One such device is an electromagnetic coupling which transfers motion across a hermetic seal by means of a rotating magnetic field. Static pull-out torque and dynamic heat build-up and pull-out torque tests of a synchronous reluctance homopolar coupling are reported herein. Coupling efficiencies are estimated for a range of speeds and torques.

Extended Krylov subspaces approximations of matrix functions. Application to computational electromagnetics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Druskin, V.; Lee, Ping; Knizhnerman, L.

There is now a growing interest in the area of using Krylov subspace approximations to compute the actions of matrix functions. The main application of this approach is the solution of ODE systems, obtained after discretization of partial differential equations by method of lines. In the event that the cost of computing the matrix inverse is relatively inexpensive, it is sometimes attractive to solve the ODE using the extended Krylov subspaces, originated by actions of both positive and negative matrix powers. Examples of such problems can be found frequently in computational electromagnetics.

A non-asymptotic homogenization theory for periodic electromagnetic structures.

PubMed

Tsukerman, Igor; Markel, Vadim A

2014-08-08

Homogenization of electromagnetic periodic composites is treated as a two-scale problem and solved by approximating the fields on both scales with eigenmodes that satisfy Maxwell's equations and boundary conditions as accurately as possible. Built into this homogenization methodology is an error indicator whose value characterizes the accuracy of homogenization. The proposed theory allows one to define not only bulk, but also position-dependent material parameters (e.g. in proximity to a physical boundary) and to quantify the trade-off between the accuracy of homogenization and its range of applicability to various illumination conditions.

Rodded shutdown system for a nuclear reactor

DOEpatents

Golden, Martin P.; Govi, Aldo R.

1978-01-01

A top mounted nuclear reactor diverse rodded shutdown system utilizing gas fed into a pressure bearing bellows region sealed at the upper extremity to an armature. The armature is attached to a neutron absorber assembly by a series of shafts and connecting means. The armature is held in an uppermost position by an electromagnet assembly or by pressurized gas in a second embodiment. Deenergizing the electromagnet assembly, or venting the pressurized gas, causes the armature to fall by the force of gravity, thereby lowering the attached absorber assembly into the reactor core.

Observation of large-scale density cavities and parametric-decay instabilities in the high-altitude discrete auroral ionosphere under pulsed electromagnetic radiation.

PubMed

Wong, A Y; Chen, J; Lee, L C; Liu, L Y

2009-03-13

A large density cavity that measured 2000 km across and 500 km in height was observed by DEMETER and Formosat/COSMIC satellites in temporal and spatial relation to a new mode of propagation of electromagnetic (em) pulses between discrete magnetic field-aligned auroral plasmas to high altitudes. Recorded positive plasma potential from satellite probes is consistent with the expulsion of electrons in the creation of density cavities. High-frequency decay spectra support the concept of parametric instabilities fed by free energy sources.

Unconditionally stable WLP-FDTD method for the modeling of electromagnetic wave propagation in gyrotropic materials.

PubMed

Li, Zheng-Wei; Xi, Xiao-Li; Zhang, Jin-Sheng; Liu, Jiang-fan

2015-12-14

The unconditional stable finite-difference time-domain (FDTD) method based on field expansion with weighted Laguerre polynomials (WLPs) is applied to model electromagnetic wave propagation in gyrotropic materials. The conventional Yee cell is modified to have the tightly coupled current density components located at the same spatial position. The perfectly matched layer (PML) is formulated in a stretched-coordinate (SC) system with the complex-frequency-shifted (CFS) factor to achieve good absorption performance. Numerical examples are shown to validate the accuracy and efficiency of the proposed method.

Awake craniotomy using electromagnetic navigation technology without rigid pin fixation.

PubMed

Morsy, Ahmed A; Ng, Wai Hoe

2015-11-01

We report our institutional experience using an electromagnetic navigation system, without rigid head fixation, for awake craniotomy patients. The StealthStation® S7 AxiEM™ navigation system (Medtronic, Inc.) was used for this technique. Detailed preoperative clinical and neuropsychological evaluations, patient education and contrast-enhanced MRI (thickness 1.5mm) were performed for each patient. The AxiEM Mobile Emitter was typically placed in a holder, which was mounted to the operating room table, and a non-invasive patient tracker was used as the patient reference device. A monitored conscious sedation technique was used in all awake craniotomy patients, and the AxiEM Navigation Pointer was used for navigation during the procedure. This offers the same accuracy as optical navigation, but without head pin fixation or interference with intraoperative neurophysiological techniques and surgical instruments. The application of the electromagnetic neuronavigation technology without rigid head fixation during an awake craniotomy is accurate, and offers superior patient comfort. It is recommended as an effective adjunctive technique for the conduct of awake surgery. Copyright © 2015 Elsevier Ltd. All rights reserved.

Not Your Ordinary GEM

NASA Technical Reports Server (NTRS)

2001-01-01

Through Small Business Innovation Research (SBIR) funding from NASA's Stennis Space Center, Geophex devised a new design for broadband electromagnetic sensors. Geophex developed a patented sensing technology, capable not only of coastal monitoring, but also a variety of other functions, including environmental pollution characterization, groundwater contamination detection, archaeological study, and mineral detection. The new technology is offered in several of the company's products the GEM-2, GEM-2A, and the GEM-3. The Geophex products consist of two primary electromagnetic coils, which are stimulated by alternating currents that generate a magnetic field in the object targeted for investigation. GEM-2 is a handheld, lightweight, programmable, digital device. GEM-2A is an airborne version of the sensor. Suspended from a helicopter, the GEM-2A is used to search for mineral deposits and to survey large tracts of land. The GEM-3 is capable of detecting buried landmines and other active munitions. GEM-3 identifies landmines by their brand names. Because each landmine has its own unique electromagnetic response to the broad frequency band emitted by the GEM-3, bomb identification and disposal strategies are made easier.

MEMS electromagnetic energy harvesters with multiple resonances

NASA Astrophysics Data System (ADS)

Nelatury, Sudarshan R.; Gray, Robert

2014-06-01

There is going on a flurry of research activity in the development of effcient energy harvesters from all branches of energy conversion. The need for developing self-powered wireless sensors and actuators to be employed in unmanned combat vehicles also seems to grow steadily. These vehicles are inducted into perilous war zones for silent watch missions. Energy management is sometimes carried out using misson-aware energy expenditure strategies. Also, when there is a requirement for constant monitoring of events, the sensors and the subsystems of combat vehicles require energy harvesters that can operate over a discrete set of spot frequencies. This paper attempts to review some of the recent techniques and the energy harvesting devices based on electromagnetic and electromechanical principles. In particular, we shall discuss the design and performance of a MEMS-harvester that exhibits multiple resonances. Frequency response of a simulated electromagnetic harvester is plotted. It has three dominant peaks at three different resonant frequencies. Variation in the load power in the normalized units as a function of load is found, which determines the matched load resistance.

A borehole-to-surface electromagnetic survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tseng, Hung-Wen; Becker, A.; Wilt, M.

1995-12-31

We have assessed the feasibility of borehole to surface electromagnetic measurements for fluid injection monitoring. To do this we performed a vertical electromagnetic profiling (VEMP) experiment at the University of California Richmond Field Station where a saline water injection zone was created at a subsurface depth of 30 meters. The methodology used is quite similar to the conventional seismic (VSP) procedure for surface to borehole measurements. In our case however, the transmitter was located in a PVC cased borehole while the receivers were deployed on the surface. With a carefully designed system operating at 9.6 kHz we were able tomore » make measurements accurate to 1 % in amplitude and 1 degree in phase. The data profiles at surface were centered on the injection well and extended for 60 m on either side of it. Measurements were made at 5 m intervals. Although the VEMP process is quite vulnerable to near surface conductivity anomalies we readily detected the flat tabular target zone which was about 3 m thick and covered an area of about 120 M{sup 2}.« less

Three-dimensional Fréchet sensitivity kernels for electromagnetic wave propagation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strickland, C. E.; Johnson, T. C.; Odom, R. I.

2015-08-28

Electromagnetic imaging methods are useful tools for monitoring subsurface changes in pore-fluid content and the associated changes in electrical permittivity and conductivity. The most common method for georadar tomography uses a high frequency ray-theoretic approximation that is valid when material variations are sufficiently small relative to the wavelength of the propagating wave. Georadar methods, however, often utilize electromagnetic waves that propagate within heterogeneous media at frequencies where ray theory may not be applicable. In this paper we describe the 3-D Fréchet sensitivity kernels for EM wave propagation. Various data functional types are formulated that consider all three components of themore » electric wavefield and incorporate near-, intermediate-, and far-field contributions. We show that EM waves exhibit substantial variations for different relative source-receiver component orientations. The 3-D sensitivities also illustrate out-of-plane effects that are not captured in 2-D sensitivity kernels and can influence results obtained using 2-D inversion methods to image structures that are in reality 3-D.« less

Transparent self-cleaning dust shield

DOEpatents

Mazumder, Malay K.; Sims, Robert A.; Wilson, James D.

2005-06-28

A transparent electromagnetic shield to protect solar panels and the like from dust deposition. The shield is a panel of clear non-conducting (dielectric) material with embedded parallel electrodes. The panel is coated with a semiconducting film. Desirably the electrodes are transparent. The electrodes are connected to a single-phase AC signal or to a multi-phase AC signal that produces a travelling electromagnetic wave. The electromagnetic field produced by the electrodes lifts dust particles away from the shield and repels charged particles. Deposited dust particles are removed when the electrodes are activated, regardless of the resistivity of the dust. Electrostatic charges on the panel are discharged by the semiconducting film. When used in conjunction with photovoltaic cells, the power for the device may be obtained from the cells themselves. For other surfaces, such as windshields, optical windows and the like, the power must be derived from an external source. One embodiment of the invention employs monitoring and detection devices to determine when the level of obscuration of the screen by dust has reached a threshold level requiring activation of the dust removal feature.

Development of the Vacuum Circuit Breaker with an Electromagnetic Actuator

NASA Astrophysics Data System (ADS)

Morita, Ayumu; Yabu, Masato; Kajiwara, Satoru

A new type of vacuum circuit breaker (VCB) has been developed, which needs a minimum of maintenance. This VCB is characterized by the following: (a) a significantly simplified driving mechanism, (b) no need for grease, and (c) a new electromagnetic actuator called a hybrid-type electromagnet. The number of movable parts is decreased to 15% of that of our conventional product with a spring drive. Solid lubricant is adopted instead of grease for almost all of the linkages, which helps to eliminate periodical lubricating maintenance. The hybrid-type electromagnet has an attractive force suitable for the spring force characteristics of the VCB through its combination of conventional plunger-type and plate-armature-type electromagnet. The VCB is held in the closed position by the attractive force of the permanent magnet without using a coil current. Its core structure is optimized to prevent the permanent magnet from demagnetization and to secure long-term reliability. To assess the solid lubricant reliability, some special tests were performed such as a rare operation test. Dynamic characteristics were measured for three specimens at intervals of a month, a year, and two years, respectively. It was confirmed that variation of the armature speed is small and the influence of the non-operation interval is negligible.

Electromagnetic processes during phase commutation in field regulated reluctance machine

NASA Astrophysics Data System (ADS)

Shishkov, A. N.; Sychev, D. A.; Zemlyansky, A. A.; Krupnova, M. N.; Funk, T. A.; Ishmet'eva, V. D.

2018-03-01

The processes of currents switching in stator windings have been explained by the existence of the electromagnetic torque ripples in the electric drive with the field-regulated reluctance machine. The maximum value of ripples in the open loop control system for the six-phase machine can reach 20 percent from the developed electromagnetic torque. This method allows one to make calculation of ripple spike towards average torque developed by the electromotor for the different number of phases. Application of a trapezoidal form of current at six phases became the solution. In case of a less number of phases than six, a ripple spike considerably increases, which is inadmissible. On the other hand, increasing the number of phases tends to the increase of the semiconductor inverter external dimensions based on the inconspicuous decreasing of a ripple spike. The creation and usage of high-speed control loops of current (HCLC) have been recommended for a reduction of the electromagnetic torque’s ripple level, as well as the appliance of positive current feedback in switching phase currents. This decision allowed one to receive a mean value of the torque more than 10%, compared to system without change, to reduce greatly ripple spike of the electromagnetic torque. The possibility of the electric drive effective operation with FRRM in emergency operation has been shown.

In vivo measurement of the 3D kinematics of the temporomandibular joint using miniaturized electromagnetic trackers: technical report.

PubMed

Baeyens, J-P; Gilomen, H; Erdmann, B; Clijsen, R; Cabri, J; Vissers, D

2013-04-01

The aim of this study was to evaluate the use of miniaturized electromagnetic trackers (1 × 0.5 × 0.5 cm) fixed on teeth of the maxilla and mandible to analyse in vivo the 3D kinematics of the temporomandibular joint (TMJ). A third sensor was fixed to the forehead, and a fourth sensor was used as a stylus pointer to detect several anatomical landmarks in order to embed a local frame on the cranium. Temporomandibular opening/closing, chewing, laterotrusion and protrusion were examined. The prime objective within this study was to rigidly attach electromagnetic minisensors on teeth. The key for a successful affixation was the kevlar interface. The distances between the two mandibular affixed sensors and between the two maxillar affixed sensors were overall smaller than 0.033 cm for position and 0.2° for attitude throughout the temporomandibular motions. The relative motions between a forehead sensor and the maxilla affixed sensor are too big to suggest a forehead sensor as an alternative for a maxilla affixed sensor. The technique using miniaturized electromagnetic trackers furthers on the methods using electromagnetic trackers on external appliances. The method allows full range of motion of the TMJ and does not disturb normal TMJ function.

Melting a Gold Sample within TEMPUS

NASA Technical Reports Server (NTRS)

2003-01-01

A gold sample is heated by the TEMPUS electromagnetic levitation furnace on STS-94, 1997, MET:10/09:20 (approximate). The sequence shows the sample being positioned electromagnetically and starting to be heated to melting. TEMPUS (stands for Tiegelfreies Elektromagnetisches Prozessiere unter Schwerelosigkeit (containerless electromagnetic processing under weightlessness). It was developed by the German Space Agency (DARA) for flight aboard Spacelab. The DARA project scientist was Igon Egry. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1R mission (STS-94, July 1-17 1997). DARA and NASA are exploring the possibility of flying an advanced version of TEMPUS on the International Space Station. (378KB JPEG, 2380 x 2676 pixels; downlinked video, higher quality not available) The MPG from which this composite was made is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300191.html.

Turbulent Transition in Electromagnetically Levitated Drops

NASA Technical Reports Server (NTRS)

Hyers, Robert W.; Trapaga, G.; Abedian, B.; Matson, D. M.; Rose, M. Franklin (Technical Monitor)

2000-01-01

Electromagnetic levitation (EML) is an important tool in materials research. Because a sample can be processed without contact with a container, experiments may be performed on high temperature, highly reactive, and undercooled liquid metals. Many of these experiments are affected by fluid flow in the sample, driven by the electromagnetic positioning force. Despite the importance of convection in these experiments, the transition to turbulence is not well understood in this system. However, we have observed a transition from laminar to turbulent flow in EML droplets in the course of microgravity experiments in TEMPUS on the Space Shuttle (STS-94). The transition occurs repeatably and over a narrow range of conditions. These experimental observations are compared with two competing theories about the transition to turbulence. Also, the results of a particle tracking study of the instabilities leading up to the transition to turbulence are presented.

Using ISS Telescopes for Electromagnetic Follow-up of Gravitational Wave Detections of NS-NS and NS-BH Mergers

NASA Technical Reports Server (NTRS)

Camp, J.; Barthelmy, S.; Blackburn, L.; Carpenter, K. G.; Gehrels, N.; Kanner, J.; Marshall, F. E.; Racusin, J. L.; Sakamoto, T.

2013-01-01

The International Space Station offers a unique platform for rapid and inexpensive deployment of space telescopes. A scientific opportunity of great potential later this decade is the use of telescopes for the electromagnetic follow-up of ground-based gravitational wave detections of neutron star and black hole mergers. We describe this possibility for OpTIIX, an ISS technology demonstration of a 1.5 m diffraction limited optical telescope assembled in space, and ISS-Lobster, a wide-field imaging X-ray telescope now under study as a potential NASA mission. Both telescopes will be mounted on pointing platforms, allowing rapid positioning to the source of a gravitational wave event. Electromagnetic follow-up rates of several per year appear likely, offering a wealth of complementary science on the mergers of black holes and neutron stars.

DIRECT CURRENT ELECTROMAGNETIC PUMP

DOEpatents

Barnes, A.H.

1957-11-01

An improved d-c electromagnetic pump is presented in which the poles, and consequently the magetic gap at the poles, are tapered to be wider at the upstream end. In addition, the cross section of the tube carryiQ the liquid metal is tapered so that the velocity of the pumped liquid increases in the downstream direction at a rate such that the counter-induced voltage in the liquid metal remains constant as it traverses the region between the poles. This configuration compensates for the distortion of the magnetic field caused by the induced voltage that would otherwise result in the lowering of the pumping capacity. This improved electromagnetic pump as practical application in the pumping of liquid metal coolants for nuclear reactors where conventional positive displacement pumps have proved unsatisfactory due to the high temperatures and the corrosive properties of the liquid metals involved.

3D vector distribution of the electro-magnetic fields on a random gold film

NASA Astrophysics Data System (ADS)

Canneson, Damien; Berini, Bruno; Buil, Stéphanie; Hermier, Jean-Pierre; Quélin, Xavier

2018-05-01

The 3D vector distribution of the electro-magnetic fields at the very close vicinity of the surface of a random gold film is studied. Such films are well known for their properties of light confinement and large fluctuations of local density of optical states. Using Finite-Difference Time-Domain simulations, we show that it is possible to determine the local orientation of the electro-magnetic fields. This allows us to obtain a complete characterization of the fields. Large fluctuations of their amplitude are observed as previously shown. Here, we demonstrate large variations of their direction depending both on the position on the random gold film, and on the distance to it. Such characterization could be useful for a better understanding of applications like the coupling of point-like dipoles to such films.

Method to Create Arbitrary Sidewall Geometries in 3-Dimensions Using Liga with a Stochastic Optimization Framework

NASA Technical Reports Server (NTRS)

Eyre, Francis B. (Inventor); Fink, Wolfgang (Inventor)

2011-01-01

Disclosed herein is a method of making a three dimensional mold comprising the steps of providing a mold substrate; exposing the substrate with an electromagnetic radiation source for a period of time sufficient to render the portion of the mold substrate susceptible to a developer to produce a modified mold substrate; and developing the modified mold with one or more developing reagents to remove the portion of the mold substrate rendered susceptible to the developer from the mold substrate, to produce the mold having a desired mold shape, wherein the electromagnetic radiation source has a fixed position, and wherein during the exposing step, the mold substrate is manipulated according to a manipulation algorithm in one or more dimensions relative to the electromagnetic radiation source; and wherein the manipulation algorithm is determined using stochastic optimization computations.

Effects of weak electromagnetic irradiation on various types of behavior in the mealworm Tenebrio molitor.

PubMed

Sheiman, I M; Kreshchenko, N D

2010-10-01

The effects of weak electromagnetic irradiation on simple forms of behavior were studied using adult Tenebrio molitor mealworms. The beetles' motor behavior was studied in conditions of different motivations, i.e., positive (food) and negative (avoidance of light), in otherwise identical experimental conditions. The beetles had to navigate a defined space to reach their target - potato or cover from light. Experiments consisted of one trial per day for five days. Target attainment time was measured in groups of beetles. Behavior in both cases developed as follows: an initial orientation reaction appeared and was followed by adaptation to the apparatus. Exposure to weak electromagnetic irradiation led to increases in the response time at the initial stages of the experiments. The effects of irradiation were seasonal in nature and differed in the two types of behavior.

Seismo-electromagnetic phenomena in the western part of the Eurasia-Nubia plate boundary

NASA Astrophysics Data System (ADS)

Gonçalves da Silva, Hugo; Bezzeghoud, Mourad; Biagi, Pier; Namorado Rosa, Rui; Salgueiro da Silva, Manuel; Caldeira, Bento; Heitor Reis, Artur; Borges, José Fernando; Tlemçani, Mouhaydine; Manso, Marco

2010-05-01

This paper presents a future research plan that aims to monitor Seismo-electromagnetic (SEM) phenomena in the western part of the Eurasia-Nubia plate boundary (WENP). This region has a significant tectonic activity [1] combined with relatively low electromagnetic noise levels and for that reason presents the possibility to perform high quality SEM measurements. Further, it is known that low-frequency [ultra (ULF), very (VLF), and low-frequencies (LF)] electromagnetic (EM) waves produce more convincing earthquake precursors (compared to higher frequencies) because of less contamination, large skin depth, and low attenuation [2]. Thus, two SEM effects will be considered: ULF electromagnetic field emissions [3], and VLF/LF radio broadcastings [4]. With respect to the ULF measurements, as a start, three ULF sensors are planned to be installed in the South of Iberian Peninsula supported by the existing networks of seismic research stations. Subsequent development of this initial plan could result in the implementation of a lager ULF monitoring network not only in the Iberian Peninsula, but also in the rest of Europe. Possible integration in the SEGMA array is now under consideration. Another perspective is to use a portable station to track seismic events. Regarding the VLF/LF radio broadcastings, a receiver is planned to be mounted in University of Évora. Radio signals from up to 10 transmitters (in these bands) of interest to study the seismic activity in the WENP region will be monitored. Actually, the radio path from the transmitter to the receiver should cross the epicentral area, therefore two possible transmitters are the ones installed in Monaco (France) and Sicily (Italy). Furthermore, the system will integrate the INFREP network and in this context it will not be restricted to WENP region. With the development of these research plans we aim to collect novel SEM data emerging from the seismic activity in the WENP region. We expect to address the time variations of EM properties of the crust/plate in relation with the strain field, and in space in relation with composition and temperature and stress fields. Further, the interplay between atmospheric (and solar) perturbations with crust perturbations will be monitored, to observe geomagnetic perturbations at different locations. Our study will be focused in the analyses of low magnitude earthquakes with M =< 4, these events are frequent in the WENP region, but have been almost completely disregarded in literature [5,6]. [1] J. Borges, A. J. S. Fitas, M. Bezzeghoud, and P. Teves-Costa, Tectonophysics 337, 373 (2001). [2] V. Chauhan, O.P. Singh, V. Kushwah, V. Singh, B. Singh, Journal of Geodynamics 48, 68 (2009). [3] L. Telesca, V. Lapenna, M. Macchiato, and K. Hattori, Earth and Planet. Science Lett. 268, 219 (2008). [4] P. F. Biagi, L. Castellana, T. Maggipinto, D. Loiacono, L. Schiavulli, T. Ligonzo, M. Fiore, E. Suciu, and A. Ermini, Nat. Hazards Earth Syst. Sci. 9, 1551 (2009). [5] A. Rozhnoi , M.S. Solovieva, O.A. Molchanov, and M. Hayakawa, Phys. and Chem. of the Earth 29, 589-598 (2004). [6] K. Hattori, I. Takahashi, C. Yoshino, N. Isezaki, H. Iwasaki, M. Harada, K. Kawabata, E. Kopytenko, Y. Kopytenko, P. Maltsev, V. Korepanov, O. Molchanov, M. Hayakawa, Y. Noda, T. Nagao, S. Uyeda, Physics and Chemistry of the Earth 29, 481-494 (2004).

Impact of electromagnetic fields on stem cells: common mechanisms at the crossroad between adult neurogenesis and osteogenesis

PubMed Central

Leone, Lucia; Podda, Maria Vittoria; Grassi, Claudio

2015-01-01

In the recent years adult neural and mesenchymal stem cells have been intensively investigated as effective resources for repair therapies. In vivo and in vitro studies have provided insights on the molecular mechanisms underlying the neurogenic and osteogenic processes in adulthood. This knowledge appears fundamental for the development of targeted strategies to manipulate stem cells. Here we review recent literature dealing with the effects of electromagnetic fields on stem cell biology that lends support to their use as a promising tool to positively influence the different steps of neurogenic and osteogenic processes. We will focus on recent studies revealing that extremely-low frequency electromagnetic fields enhance adult hippocampal neurogenesis by inducing epigenetic modifications on the regulatory sequences of genes responsible for neural stem cell proliferation and neuronal differentiation. In light of the emerging critical role played by chromatin modifications in maintaining the stemness as well as in regulating stem cell differentiation, we will also attempt to exploit epigenetic changes that can represent common targets for electromagnetic field effects on neurogenic and osteogenic processes. PMID:26124705

No effects of pulsed radio frequency electromagnetic fields on melatonin, cortisol, and selected markers of the immune system in man.

PubMed

Radon, K; Parera, D; Rose, D M; Jung, D; Vollrath, L

2001-05-01

There is growing public concern that radio frequency electromagnetic fields may have adverse biological effects. In the present study eight healthy male students were tested to see whether or not radio frequency electromagnetic fields as used in modern digital wireless telecommunication (GSM standard) have noticeable effects on salivary melatonin, cortisol, neopterin, and immunoglobulin A (sIgA) levels during and several hours after exposure. In a specifically designed, shielded experimental chamber, the circularly polarized electromagnetic field applied was transmitted by an antenna positioned 10 cm behind the head of upright sitting test persons. The carrier frequency of 900 MHz was pulsed with 217 Hz (average power flux density 1 W/m2). In double blind trials, each test person underwent a total of 20 randomly allotted 4 hour periods of exposure and sham exposure, equally distributed at day and night. The results obtained show that the salivary concentrations of melatonin, cortisol, neopterin and sIgA did not differ significantly between exposure and sham exposure. Copyright 2001 Wiley-Liss, Inc.

A metamaterial electromagnetic energy rectifying surface with high harvesting efficiency

NASA Astrophysics Data System (ADS)

Duan, Xin; Chen, Xing; Zhou, Lin

2016-12-01

A novel metamaterial rectifying surface (MRS) for electromagnetic energy capture and rectification with high harvesting efficiency is presented. It is fabricated on a three-layer printed circuit board, which comprises an array of periodic metamaterial particles in the shape of mirrored split rings, a metal ground, and integrated rectifiers employing Schottky diodes. Perfect impedance matching is engineered at two interfaces, i.e. one between free space and the surface, and the other between the metamaterial particles and the rectifiers, which are connected through optimally positioned vias. Therefore, the incident electromagnetic power is captured with almost no reflection by the metamaterial particles, then channeled maximally to the rectifiers, and finally converted to direct current efficiently. Moreover, the rectifiers are behind the metal ground, avoiding the disturbance of high power incident electromagnetic waves. Such a MRS working at 2.45 GHz is designed, manufactured and measured, achieving a harvesting efficiency up to 66.9% under an incident power density of 5 mW/cm2, compared with a simulated efficiency of 72.9%. This high harvesting efficiency makes the proposed MRS an effective receiving device in practical microwave power transmission applications.

Scaling similarities of multiple fracturing of solid materials

NASA Astrophysics Data System (ADS)

Kapiris, P. G.; Balasis, G. T.; Kopanas, J. A.; Antonopoulos, G. N.; Peratzakis, A. S.; Eftaxias, K. A.

2004-02-01

It has recently reported that electromagnetic flashes of low-energy gamma-rays emitted during multi-fracturing on a neutron star, and electromagnetic pulses emitted in the laboratory by a disordered material subjected to an increasing external load, share distinctive statistical properties with earthquakes, such as power-law energy distributions (Cheng et al., 1996; Kossobokov et al., 2000; Rabinovitch et al., 2001; Sornette and Helmstetter, 2002). The neutron starquakes may release strain energies up to 1046 erg, while, the fractures in laboratory samples release strain energies approximately a fraction of an erg. An earthquake fault region can build up strain energy up to approximately 1026 erg for the strongest earthquakes. Clear sequences of kilohertz-megahertz electromagnetic avalanches have been detected from a few days up to a few hours prior to recent destructive earthquakes in Greece. A question that arises effortlessly is if the pre-seismic electromagnetic fluctuations also share the same statistical properties. Our study justifies a positive answer. Our analysis also reveals "symptoms" of a transition to the main rupture common with earthquake sequences and acoustic emission pulses observed during laboratory experiments (Maes et al., 1998).

(abstract) Using an Inversion Algorithm to Retrieve Parameters and Monitor Changes over Forested Areas from SAR Data

NASA Technical Reports Server (NTRS)

Moghaddam, Mahta

1995-01-01

In this work, the application of an inversion algorithm based on a nonlinear opimization technique to retrieve forest parameters from multifrequency polarimetric SAR data is discussed. The approach discussed here allows for retrieving and monitoring changes in forest parameters in a quantative and systematic fashion using SAR data. The parameters to be inverted directly from the data are the electromagnetic scattering properties of the forest components such as their dielectric constants and size characteristics. Once these are known, attributes such as canopy moisture content can be obtained, which are useful in the ecosystem models.

Observation of sediment resuspension in Old Tampa Bay, Florida

USGS Publications Warehouse

Schoellhamer, David H.; ,

1990-01-01

Equipment and methodology have been developed to monitor sediment resuspension at two sites in Old Tampa Bay. Velocities are measured with electromagnetic current meters and suspended solids and turbidity are monitored with optical backscatterance sensors. In late November 1989, a vertical array of instrument pairs was deployed from a permanent platform at a deep-water site, and a submersible instrument package with a single pair of instruments was deployed at a shallow-water site. Wind waves caused resuspension at the shallow-water site, but not at the deeper platform site, and spring tidal currents did not cause resuspension at either site.

Nonlinear metamaterials for electromagnetic energy harvesting (Conference Presentation)

NASA Astrophysics Data System (ADS)

Oumbe Tekam, Gabin Thibaut; Ginis, Vincent; Seetharamdoo, Divitha; Danckaert, Jan

2016-09-01

Surrounded by electromagnetic radiation coming from wireless power transfer to consumer devices such as mobile phones, computers and television, our society is facing the scientific and technological challenge to recover energy that is otherwise lost to the environment. Energy harvesting is an emerging field of research focused on this largely unsolved problem, especially in the microwave regime. Metamaterials provide a very promising platform to meet this purpose. These artificial materials are made from subwavelength building blocks, and can be designed by resonate at particular frequencies, depending on their shape, geometry, size, and orientation. In this work, we show that an efficient electromagnetic energy harvester can be design by inserting a nonlinear element directly within the metamaterial unit cell, leading to the conversion of RF input power to DC charge accumulation. The electromagnetic energy harvester operating at microwave frequencies is built from a cut-wire metasurface, which operates as a quasistatic electric dipole resonator. Using the equivalent electrical circuit, we design the parameters to tune the resonance frequency of the harvester at the desired frequency, and we compare these results with numerical simulations. Finally, we discuss the efficiency of our metamaterial energy harvesters. This work potentially offers a variety of applications, for example in the telecommunications industry to charge phones, in robotics to power microrobots, and also in medicine to advance pacemakers or health monitoring sensors.

A literature review of transmission effectiveness and electromagnetic compatibility in home telemedicine environments to evaluate safety and security.

PubMed

Carranza, Noemí; Ramos, Victoria; Lizana, Francisca G; García, Jorge; del Pozo, Alejando; Monteagudo, José Luis

2010-09-01

The objective of this study was to determine already reported cases of transmission/reception failure and interferences to evaluate the safety and security of the new mobile home telemedicine systems. The literature published in the last 10 years (1998-2009) has been reviewed, by searching in several databases. Searches on transmission effectiveness and electromagnetic compatibility were made manually through journals, conference proceedings, and also the healthcare technology assessment agencies' Web pages. Search strategies developed through electronic databases and manual search identified a total of 886 references, with 44 finally being included in the results. They have been divided by technology in the transmission/reception effectiveness studies, and according to the type of medical device in the case of electromagnetic interferences studies. The study reveals that there are numerous publications on telemedicine and home-monitoring systems using wireless networks. However, literature on effectiveness in terms of connectivity and transmission problems and electromagnetic interferences is limited. From the collected studies, it can be concluded that there are transmission failures, low-coverage areas, errors in the transmission of packets, and so on. Moreover, cases of serious interferences in medical instruments have also been reported. These facts highlight the lack of studies and specific recommendations to be followed in the implementation of biomonitoring systems in domestic environments using wireless networks.

Effects of Pulsed Electromagnetic Fields on Breast Cancer Cell Line MCF 7 Using Absorption Spectroscopy.

PubMed

Alcantara, Dominic Z; Soliman, Ian Jerry S; Pobre, Romeric F; Naguib, Raouf N G

2017-07-01

We present an analysis of the effects of pulsed electromagnetic fields (PEMF) with 3.3 MHz carrier frequency and modulated by audio resonant frequencies on the MCF-7 breast cancer cell line in vitro using absorption spectroscopy. This involves a fluorescence dye called PrestoBlue™ Cell Viability Reagent and a spectrophotometry to test the viability of MCF-7 breast cancer cells under different PEMF treatment conditions in terms of the cell absorption values. The DNA molecule of the MCF-7 breast cancer cells has an electric dipole property that renders it sensitive and reactive to applied electromagnetic fields. Resonant frequencies derived from four genes mutated in MCF-7 breast cancer cells [rapamycin-insensitive companion of mammalian target of rapamycin (RICTOR), peroxisome proliferator-activated receptor (PPARG), Nijmegen breakage syndrome 1 (NBN) and checkpoint kinase 2 (CHEK2)] were applied in generating square pulsed electromagnetic waves. Effects were monitored through measurement of absorption of the samples with PrestoBlue™, and the significance of the treatment was determined using the t-test. There was a significant effect on MCF-7 cells after treatment with PEMF at the resonant frequencies of the following genes for specific durations of exposure: RICTOR for 10 min, PPARG for 10 min, NBN for 15 min, and CHEK2 for 5 min. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications

PubMed Central

Di Sante, Raffaella

2015-01-01

In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS) have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques. PMID:26263987

Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications.

PubMed

Di Sante, Raffaella

2015-07-30

In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS) have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques.

Main Pipelines Corrosion Monitoring Device

NASA Astrophysics Data System (ADS)

Anatoliy, Bazhenov; Galina, Bondareva; Natalia, Grivennaya; Sergey, Malygin; Mikhail, Goryainov

2017-01-01

The aim of the article is to substantiate the technical solution for the problem of monitoring corrosion changes in oil and gas pipelines with use (using) of an electromagnetic NDT method. Pipeline wall thinning under operating conditions can lead to perforations and leakage of the product to be transported outside the pipeline. In most cases there is danger for human life and environment. Monitoring of corrosion changes in pipeline inner wall under operating conditions is complicated because pipelines are mainly made of structural steels with conductive and magnetic properties that complicate test signal passage through the entire thickness of the object under study. The technical solution of this problem lies in monitoring of the internal corrosion changes in pipes under operating conditions in order to increase safety of pipelines by automated prediction of achieving the threshold pre-crash values due to corrosion.

Electromagnetic navigational bronchoscopy and robotic-assisted thoracic surgery.

PubMed

Christie, Sara

2014-06-01

With the use of electromagnetic navigational bronchoscopy and robotics, lung lesions can be diagnosed and resected during one surgical procedure. Global positioning system technology allows surgeons to identify and mark a thoracic tumor, and then robotics technology allows them to perform minimally invasive resection and cancer staging procedures. Nurses on the perioperative robotics team must consider the logistics of providing safe and competent care when performing combined procedures during one surgical encounter. Instrumentation, OR organization and room setup, and patient positioning are important factors to consider to complete the procedure systematically and efficiently. This revolutionary concept of combining navigational bronchoscopy with robotics requires a team of dedicated nurses to facilitate the sequence of events essential for providing optimal patient outcomes in highly advanced surgical procedures. Copyright © 2014 AORN, Inc. Published by Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

X. Zhao, S. Ramakrishnan, J. Lawson, C.Neumeyer, R. Marsala, H. Schneider, Engineering Operations

NSTX at Princeton Plasma Physics Laboratory (PPPL) requires sophisticated plasma positioning control system for stable plasma operation. TF magnetic coils and PF magnetic coils provide electromagnetic fields to position and shape the plasma vertically and horizontally respectively. NSTX utilizes twenty six coil power supplies to establish and initiate electromagnetic fields through the coil system for plasma control. A power protection and interlock system is utilized to detect power system faults and protect the TF coils and PF coils against excessive electromechanical forces, overheating, and over current. Upon detecting any fault condition the power system is restricted, and it is eithermore » prevented from initializing or suppressed to de-energize coil power during pulsing. Power fault status is immediately reported to the computer system. This paper describes the design and operation of NSTX's protection and interlocking system and possible future expansion.« less

Iterative electromagnetic Born inversion applied to earth conductivity imaging

NASA Astrophysics Data System (ADS)

Alumbaugh, D. L.

1993-08-01

This thesis investigates the use of a fast imaging technique to deduce the spatial conductivity distribution in the earth from low frequency (less than 1 MHz), cross well electromagnetic (EM) measurements. The theory embodied in this work is the extension of previous strategies and is based on the Born series approximation to solve both the forward and inverse problem. Nonlinear integral equations are employed to derive the series expansion which accounts for the scattered magnetic fields that are generated by inhomogeneities embedded in either a homogenous or a layered earth. A sinusoidally oscillating, vertically oriented magnetic dipole is employed as a source, and it is assumed that the scattering bodies are azimuthally symmetric about the source dipole axis. The use of this model geometry reduces the 3-D vector problem to a more manageable 2-D scalar form. The validity of the cross well EM method is tested by applying the imaging scheme to two sets of field data. Images of the data collected at the Devine, Texas test site show excellent correlation with the well logs. Unfortunately there is a drift error present in the data that limits the accuracy of the results. A more complete set of data collected at the Richmond field station in Richmond, California demonstrates that cross well EM can be successfully employed to monitor the position of an injected mass of salt water. Both the data and the resulting images clearly indicate the plume migrates toward the north-northwest. The plausibility of these conclusions is verified by applying the imaging code to synthetic data generated by a 3-D sheet model.

Monitoring complex detectors: the uSOP approach in the Belle II experiment

NASA Astrophysics Data System (ADS)

Di Capua, F.; Aloisio, A.; Ameli, F.; Anastasio, A.; Branchini, P.; Giordano, R.; Izzo, V.; Tortone, G.

2017-08-01

uSOP is a general purpose single board computer designed for deep embedded applications in control and monitoring of detectors, sensors and complex laboratory equipments. It is based on the AM3358 (1 GHz ARM Cortex A8 processor), equipped with USB and Ethernet interfaces. On-board RAM and solid state storage allows hosting a full LINUX distribution. In this paper we discuss the main aspects of the hardware and software design and the expandable peripheral architecture built around field busses. We report on several applications of uSOP system in the Belle II experiment, presently under construction at KEK (Tsukuba, Japan). In particular we will report the deployment of uSOP in the monitoring system framework of the endcap electromagnetic calorimeter.

Robust electromagnetically guided endoscopic procedure using enhanced particle swarm optimization for multimodal information fusion.

PubMed

Luo, Xiongbiao; Wan, Ying; He, Xiangjian

2015-04-01

Electromagnetically guided endoscopic procedure, which aims at accurately and robustly localizing the endoscope, involves multimodal sensory information during interventions. However, it still remains challenging in how to integrate these information for precise and stable endoscopic guidance. To tackle such a challenge, this paper proposes a new framework on the basis of an enhanced particle swarm optimization method to effectively fuse these information for accurate and continuous endoscope localization. The authors use the particle swarm optimization method, which is one of stochastic evolutionary computation algorithms, to effectively fuse the multimodal information including preoperative information (i.e., computed tomography images) as a frame of reference, endoscopic camera videos, and positional sensor measurements (i.e., electromagnetic sensor outputs). Since the evolutionary computation method usually limits its possible premature convergence and evolutionary factors, the authors introduce the current (endoscopic camera and electromagnetic sensor's) observation to boost the particle swarm optimization and also adaptively update evolutionary parameters in accordance with spatial constraints and the current observation, resulting in advantageous performance in the enhanced algorithm. The experimental results demonstrate that the authors' proposed method provides a more accurate and robust endoscopic guidance framework than state-of-the-art methods. The average guidance accuracy of the authors' framework was about 3.0 mm and 5.6° while the previous methods show at least 3.9 mm and 7.0°. The average position and orientation smoothness of their method was 1.0 mm and 1.6°, which is significantly better than the other methods at least with (2.0 mm and 2.6°). Additionally, the average visual quality of the endoscopic guidance was improved to 0.29. A robust electromagnetically guided endoscopy framework was proposed on the basis of an enhanced particle swarm optimization method with using the current observation information and adaptive evolutionary factors. The authors proposed framework greatly reduced the guidance errors from (4.3, 7.8) to (3.0 mm, 5.6°), compared to state-of-the-art methods.

Enrichment of magnetic particles using temperature and magnetic field gradients induced by benchtop fabricated micro-electromagnets.

PubMed

Hosseini, A; Philpott, D N; Soleymani, L

2017-11-21

The active transport of analytes inside biosensing systems is important for reducing the response time and enhancing the limit-of-detection of these systems. Due to the ease of functionalization with bio-recognition agents and manipulation with magnetic fields, magnetic particles are widely used for active and directed transport of biological analytes. On-chip active electromagnets are ideally suited for manipulating magnetic particles in an automated and miniaturized fashion inside biosensing systems. Unfortunately, the magnetic force exerted by these devices decays rapidly as we move away from the device edges, and increasing the generated force to the levels necessary for particle manipulation requires a parallel increase in the applied current and the resultant Joule heating. In this paper, we designed a study to understand the combined role of thermal and magnetic forces on the movement of magnetic particles in order to extend the interaction distance of on-chip magnetic devices beyond the device edges. For this purpose, we used a rapid prototyping method to create an active/passive on-chip electromagnet with a micro/nano-structured active layer and a patterned ferromagnetic passive layer. We demonstrated that the measured terminal velocities of particles positioned near the electromagnet edge (∼5.5 μm) closely reflect the values obtained by multi-physics modelling. Interestingly, we observed a two orders of magnitude deviation between the experimental and modelling results for the terminal velocities of particles far from the electromagnet edge (∼55.5 μm). Heat modelling of the system using experimentally-measured thermal gradients indicates that this discrepancy is related to the enhanced fluid movement caused by thermal forces. This study enables the rational design of thermo-magnetic systems for thermally driving and magnetically capturing particles that are positioned at distances tens to hundreds of microns away from the edges of on-chip magnetic devices.

Thunderstorm monitoring and lightning warning, operational applications of the Safir system

NASA Technical Reports Server (NTRS)

Richard, Philippe

1991-01-01

During the past years a new range of studies have been opened by the application of electromagnetic localization techniques to the field of thunderstorm remote sensing. VHF localization techniques were used in particular for the analysis of lightning discharges and gave access to time resolved 3-D images of lightning discharges within thunderclouds. Detection and localization techniques developed have been applied to the design of the SAFIR system. This development's main objective was the design of an operational system capable of assessing and warning in real time for lightning hazards and potential thunderstorm hazards. The SAFIR system main detection technique is the long range interferometric localization of thunderstorm electromagnetic activity; the system performs the localization of intracloud and cloud to ground lightning discharges and the analysis of the characteristics of the activity.

Analysis of Forbush decreases during strong geomagnetic disturbances in March-April 2001

NASA Astrophysics Data System (ADS)

Kravtsova, M. V.; Sdobnov, V. E.

2014-08-01

Using ground-based cosmic-ray (CR) observations on the worldwide network of neutron monitors, we have studied the variations in CR rigidity spectrum, anisotropy, and planetary system of geomagnetic cutoff rigidities during Forbush decreases in March-April 2001 by the global spectrographic method. By jointly analyzing ground-based and satellite measurements, we have determined the parameters of the CR rigidity spectrum that reflect the electromagnetic characteristics of the heliospheric fields in each hour of observations within the framework of the model of CR modulation by the heliosphere's regular electromagnetic fields. The rigidity spectra of the variations and the relative changes in the intensity of CRs with rigidities of 4 and 10 GV in the solar-ecliptic geocentric coordinate system are presented in specific periods of the investigated events.

Resonant absorption and amplification of circularly-polarized waves in inhomogeneous chiral media.

PubMed

Kim, Seulong; Kim, Kihong

2016-01-25

It has been found that in the media where the dielectric permittivity ε or the magnetic permeability μ is near zero and in transition metamaterials where ε or μ changes from positive to negative values, there occur a strong absorption or amplification of the electromagnetic wave energy in the presence of an infinitesimally small damping or gain and a strong enhancement of the electromagnetic fields. We attribute these phenomena to the mode conversion of transverse electromagnetic waves into longitudinal plasma oscillations and its inverse process. In this paper, we study analogous phenomena occurring in chiral media theoretically using the invariant imbedding method. In uniform isotropic chiral media, right-circularly-polarized and left-circularly-polarized waves are the eigen-modes of propagation with different effective refractive indices n(+) and n(-), whereas in the chiral media with a nonuniform impedance variation, they are no longer the eigenmodes and are coupled to each other. We find that both in uniform chiral slabs where either n(+) or n(-) is near zero and in chiral transition metamaterials where n(+) or n(-) changes from positive to negative values, a strong absorption or amplification of circularly-polarized waves occurs in the presence of an infinitesimally small damping or gain. We present detailed calculations of the mode conversion coefficient, which measures the fraction of the electromagnetic wave energy absorbed into the medium, for various configurations of ε and μ with an emphasis on the influence of a nonuniform impedance. We propose possible applications of these phenomena to linear and nonlinear optical devices that react selectively to the helicity of the circular polarization.

Navigation with Electromagnetic Tracking for Interventional Radiology Procedures

PubMed Central

Wood, Bradford J.; Zhang, Hui; Durrani, Amir; Glossop, Neil; Ranjan, Sohan; Lindisch, David; Levy, Eliott; Banovac, Filip; Borgert, Joern; Krueger, Sascha; Kruecker, Jochen; Viswanathan, Anand; Cleary, Kevin

2008-01-01

PURPOSE To assess the feasibility of the use of preprocedural imaging for guide wire, catheter, and needle navigation with electromagnetic tracking in phantom and animal models. MATERIALS AND METHODS An image-guided intervention software system was developed based on open-source software components. Catheters, needles, and guide wires were constructed with small position and orientation sensors in the tips. A tetrahedral-shaped weak electromagnetic field generator was placed in proximity to an abdominal vascular phantom or three pigs on the angiography table. Preprocedural computed tomographic (CT) images of the phantom or pig were loaded into custom-developed tracking, registration, navigation, and rendering software. Devices were manipulated within the phantom or pig with guidance from the previously acquired CT scan and simultaneous real-time angiography. Navigation within positron emission tomography (PET) and magnetic resonance (MR) volumetric datasets was also performed. External and endovascular fiducials were used for registration in the phantom, and registration error and tracking error were estimated. RESULTS The CT scan position of the devices within phantoms and pigs was accurately determined during angiography and biopsy procedures, with manageable error for some applications. Preprocedural CT depicted the anatomy in the region of the devices with real-time position updating and minimal registration error and tracking error (<5 mm). PET can also be used with this system to guide percutaneous biopsies to the most metabolically active region of a tumor. CONCLUSIONS Previously acquired CT, MR, or PET data can be accurately codisplayed during procedures with reconstructed imaging based on the position and orientation of catheters, guide wires, or needles. Multimodality interventions are feasible by allowing the real-time updated display of previously acquired functional or morphologic imaging during angiography, biopsy, and ablation. PMID:15802449

Feasibility of using ground-penetrating radar to quantify root mass in Florida's intensively managed pine plantations

Treesearch

John Butnor; Brian Roth; Kurt Johnsen

2005-01-01

Tree root systems are commonly evaluated via labor intensive, destructive, time-consuming excavations. Ground-penetrating radar (GPR) can be used to detect and monitor roots if there is sufficient electromagnetic contrast with the surrounding soil matrix. This methodology is commonly used in civil engineering for non-destructive testing of concrete as well as road and...

Minigrant Program. A Differential Geometric Approach to Electromagnetic Lens Design.

DTIC Science & Technology

1984-06-01

34,___" ,. --. 5 %’’ %, ;_-- - .-.- -. ...’ .¢ MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU OF STANDARDS-1963-A _"O i ’,... • . , w .T..rm,..p,. .. , .e W...ORGANIZATION REPORT NU,/dEHj) AD"A144 239 AFOSRTR- 3 4 - 0 5 9 6 aNIAME OF PERFORMING ORGANIZATION 6b OFFICE SYMBOL 74. NAME OF MONITORING ORGANIZATION

EMC system test performance on Spacelab

NASA Astrophysics Data System (ADS)

Schwan, F.

1982-07-01

Electromagnetic compatibility testing of the Spacelab engineering model is discussed. Documentation, test procedures (including data monitoring and test configuration set up) and performance assessment approach are described. Equipment was assembled into selected representative flight configurations. The physical and functional interfaces between the subsystems were demonstrated within the integration and test sequence which culminated in the flyable configuration Long Module plus one Pallet.

Medical radar considerations for detecting and monitoring Crohn's disease

NASA Astrophysics Data System (ADS)

Smith, Sonny; Narayanan, Ram M.; Messaris, Evangelos

2014-05-01

Crohn's disease is a condition that causes inflammation and associated complications along any section of the digestive tract. Over the years, numerous radiological and endoscopic methods as well as the use of ultrasound have been developed to examine and diagnose inflammatory bowel disorders such as Crohn's disease. While such techniques have much merit, an alternative medical solution that is safe, non-invasive, and inexpensive is proposed in this paper. Reflections from electromagnetic signals transmitted by an ultra-wide band (UWB) radar allow for not only range (or extent) information but also spectral analysis of a given target of interest. Moreover, the radar cross-section (RCS) of an object measures how detectable the electromagnetic return energy of such an object is to the radar. In the preliminary phase of research, we investigate how disparities in the dielectric properties of diseased versus non-diseased portions of the intestines can aid in the detection of Crohn's disease. RCS analysis from finite-difference time-domain (FDTD) method simulations using a simple 3D model of the intestines are presented. The ultimate goal of our research is to design a UWB radar system using a suitable waveform to detect and monitor Crohn's disease.

High-Frequency Electromagnetic Impedance Measurements for Characterization, Monitoring and Verification Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ki Ha; Becker, Alex; Tseng, Hung-Wen

2004-06-16

Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic (EM) measurements at frequencies between 0.1 and 100 MHz are important for such applications, because the induction number of many targets is small and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high-resolution imaging, accurate measurements are necessary so the field data canmore » be mapped into the space of the subsurface parameters. We are developing a non-invasive method for accurately mapping the electrical conductivity and dielectric permittivity of the shallow subsurface using the EM impedance approach (Frangos, 2001; Lee and Becker, 2001; Song et al., 2002, Tseng et al., 2003). Electric and magnetic sensors are being tested and calibrated on sea water and in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques.« less

[Effects of electromagnetic radiation on health and immune function of operators].

PubMed

Li, Yan-zhong; Chen, Shao-hua; Zhao, Ke-fu; Gui, Yun; Fang, Si-xin; Xu, Ying; Ma, Zi-jian

2013-08-01

To investigate the effects of electromagnetic radiation on the physiological indices and immune function of operators. The general conditions and electromagnetic radiation awareness rate of 205 operators under electromagnetic radiation were evaluated using a self-designed questionnaire. Physical examination, electrocardiography, and routine urine test were performed in these operators. Peripheral blood was collected from the operators under electromagnetic radiation for blood cell counting and biochemical testing, and their peripheral blood lymphocytes were cultured for determination of chromosomal aberrant frequency and micronucleus frequency. The data from these operators (exposure group) were compared with those of 95 ordinary individuals (control group). The chief complaint of giddiness, tiredness, dizziness, and amnesia showed significant differences between the exposure group and control group (P < 0.01), and the difference in headache became larger with an increase in working years. The awareness rate of electromagnetic radiation damage was significantly higher in the exposure group than in the control group. The difference in bradycardia was significant between the two groups (P <0.01), and the incidence was higher with longer working years. Significant differences between the two groups were also found in the numbers of individuals with elevated alanine aminotransferase, total bilirubin, and direct bilirubin (P < 0.01), populations with increased lymphocyte ratio and decreased neutrophil ratio (P < 0.01), populations with positive occult blood, urobilinogen, and bilirubin tests, and the number of individuals with increased micronucleus frequency of cultured peripheral blood lymphocytes (P < 0.01). In addition, the exposure group had significantly increased complement C3 and C4 (P < 0.01), significantly increased IgG (P < 0.05), and significantly decreased IgM (P < 0.01), as compared with the control group. Electromagnetic radiation may lead to the changes in physiological indices, genetic effects, and immune function and affect the health and immune function in operators. The adverse effects are increased as the working years increase. So it is important to strengthen occupational protection of operators under electromagnetic radiation.

Two position optical element actuator device

DOEpatents

Holdener, Fred R.; Boyd, Robert D.

2002-01-01

The present invention is a two position optical element actuator device utilizing a powered means to hold an actuation arm, to which an optical element is attached, in a first position. A non-powered means drives the actuation arm to a second position, when the powered means ceases to receive power. The optical element may be a electromagnetic (EM) radiation or particle source, an instrument, or EM radiation or particle transmissive, reflective or absorptive elements. A bearing is used to transfer motion and smoothly transition the actuation arm from the first to second position.

The 20th Aerospace Mechanisms Symposium

NASA Technical Reports Server (NTRS)

1986-01-01

Numerous topics related to aerospace mechanisms were discussed. Deployable structures, electromagnetic devices, tribology, hydraulic actuators, positioning mechanisms, electric motors, communication satellite instruments, redundancy, lubricants, bearings, space stations, rotating joints, and teleoperators are among the topics covered.

Accounting hierarchical heterogeneity of rock during its working off by explosive methods

NASA Astrophysics Data System (ADS)

Hachay, Olga; Khachay, Oleg

2017-04-01

First the phenomenon of zonal disintegration of rocks around excavations have been described and published as a discovery. Questions of structures formation are related to the fundamental problems of the natural sciences and the study of the structural appearance is one of the most important purposes of scientific knowledge. In real systems, considered in physics, it had been found spatial and temporal structures. The temporal structures are inseparable from the dynamics of the system, here it are particularly important principles of pointedness and causality. Formation of structures by irreversible processes is associated with a qualitative leap when it reaches the critical parameters. Self organization is a supercritical phenomenon when the system parameters exceed their critical values. When the system deviates greatly from its equilibrium, it's state variables satisfy the nonlinear equations. Non linearity is an important and common feature of the processes taking place far from equilibrium. By that the supercritical output of entropy is only possible if there is an unusual, special internal structure of the system. This means that self-organization is not a universal property of matter; it exists in certain internal and external conditions and is not associated with a particular class of substances. So, there are two classes of irreversible processes: 1.Destroying of the structure near the equilibrium position that is a universal property of systems under arbitrary conditions. 2. Occuring structures far from the equilibrium position under the conditions that the system is open and has a non-linear internal dynamics and its external parameters have supercritical parameters. Prigogine called them dissipative structures. The study of the morphology and dynamics of the migration of these zones is of particular importance when developing deep deposits, complicated by, dynamically events as rock bursts. Important tools for this study are the geophysical surveys. Because the information about the structure and state of the environment can be obtained from the geophysical data by interpreting them in frames of the model, which is an approximation to the real environment, therefore you must select it from the class of physically and geologically reasonable. For a description of the geological environment in the form of a rock massif with its natural and technogenic heterogeneity we should use more adequate description as is a discrete model of the environment in the form of a piece wise non-homogeneous block media with embedded heterogeneities of lower rank than the block size . This nesting can be traced back several times, ie, changing the scale of the study, we see that the heterogeneity of lower rank now appear as blocks for the irregularities of the next rank. The simple average of the measured geophysical parameters can lead to a distorted view of the structure of the environment and its evolution. The Institute of Geophysics, UB RAS has developed a hardware-methodological and interpretative system for studying the structure and state of complex geological environment, which has the potential instability and the ability to rebuild the hierarchy structure with significant external influence. The basis of this complex is the developed 3-D technique planshet electromagnetic induction studies in frequency geometrical variant, resting on one side on the interpretation software system for 3-D alternating electromagnetic fields, and on the other hand on developed by Ph.D. A.I.Chelovechkov device for carrying out the inductive research. On the basis of this technology the active monitoring of the structure and state of the rock massif inside the mines of different material composition can be provided, it can be carried out to detect short-term precursors of strong dynamic phenomena according to the electromagnetic induction monitoring. There are developed algorithms for modeling of electromagnetic fields in hierarchic heterogeneous media.

Multileaf collimator tracking integrated with a novel x-ray imaging system and external surrogate monitoring

NASA Astrophysics Data System (ADS)

Krauss, Andreas; Fast, Martin F.; Nill, Simeon; Oelfke, Uwe

2012-04-01

We have previously developed a tumour tracking system, which adapts the aperture of a Siemens 160 MLC to electromagnetically monitored target motion. In this study, we exploit the use of a novel linac-mounted kilovoltage x-ray imaging system for MLC tracking. The unique in-line geometry of the imaging system allows the detection of target motion perpendicular to the treatment beam (i.e. the directions usually featuring steep dose gradients). We utilized the imaging system either alone or in combination with an external surrogate monitoring system. We equipped a Siemens ARTISTE linac with two flat panel detectors, one directly underneath the linac head for motion monitoring and the other underneath the patient couch for geometric tracking accuracy assessments. A programmable phantom with an embedded metal marker reproduced three patient breathing traces. For MLC tracking based on x-ray imaging alone, marker position was detected at a frame rate of 7.1 Hz. For the combined external and internal motion monitoring system, a total of only 85 x-ray images were acquired prior to or in between the delivery of ten segments of an IMRT beam. External motion was monitored with a potentiometer. A correlation model between external and internal motion was established. The real-time component of the MLC tracking procedure then relied solely on the correlation model estimations of internal motion based on the external signal. Geometric tracking accuracies were 0.6 mm (1.1 mm) and 1.8 mm (1.6 mm) in directions perpendicular and parallel to the leaf travel direction for the x-ray-only (the combined external and internal) motion monitoring system in spite of a total system latency of ˜0.62 s (˜0.51 s). Dosimetric accuracy for a highly modulated IMRT beam-assessed through radiographic film dosimetry-improved substantially when tracking was applied, but depended strongly on the respective geometric tracking accuracy. In conclusion, we have for the first time integrated MLC tracking with x-ray imaging in the in-line geometry and demonstrated highly accurate respiratory motion tracking.

The QuakeFinder Magnetometer Network - a Platform for Earth and Space Science Research

NASA Astrophysics Data System (ADS)

Bleier, T.; Kappler, K. N.; Schneider, D.

2016-12-01

QuakeFinder (QF) is a humanitarian research and development project attempting to characterize earth-emitting electromagnetic (EM) signals as potential precursors to earthquakes. Beginning in 2005, QF designed, built, deployed and now maintains an array of 165 remote monitoring stations in 6 countries (US/California, Taiwan, Greece, Indonesia, Peru and Chile). Having amassed approximately 70 TB of data and greater than 140 earthquakes (M4+), QF is focused on the data analysis and signal processing algorithms in our effort to enable a forecasting capability. QF's autonomous stations, located along major fault lines, collect and transmit electromagnetic readings from 3-axis induction magnetometers and positive/negative ion sensors, a geophone, as well as various station health status and local conditions. The induction magnetometers, oriented N-S,E-W and vertically, have a 40 nT range and 1 pT sensitivity. Data is continuously collected at 50 samples/sec (sps), GPS time-stamped and transmitted, primarily through cell phone networks, to our data center in Palo Alto, California. The induction magnetometers routinely detect subtle geomagnetic and ionospheric disturbances as observed worldwide. QF seeks to make available both historic data and the array platform to strategic partners in the EM-related research and operation fields. The QF system will be described in detail with examples of local and regional geomagnetic activity. The stations are robust and will be undergoing a system-level upgrade in the near future. Domestically, QF maintains a 98% `up time' among the 120 stations in California while internationally our metric is typically near 80%. Irregular cell phone reception is chief among the reasons for outages although little data has been lost as the stations can store up to 90 days of data. These data are retrieved by QF personnel or, when communication is reestablished, the QF data ingest process automatically updates the database. Planned station upgrades include a new processor and ARM board with additional data channels, increased robustness in station health monitoring and self-recovery features, induction magnetometers with a deeper frequency range, and possibly the addition of 3-axis flux gate magnetometers to expand the measurement range to 2000 nT.

Time-lapse seismic - repeatability versus usefulness and 2D versus 3D

NASA Astrophysics Data System (ADS)

Landro, M.

2017-12-01

Time-lapse seismic has developed rapidly over the past decades, especially for monitoring of oil and gas reservoirs and subsurface storage of CO2. I will review and discuss some of the critical enabling factors for the commercial success of this technology. It was early realized that how well we are able to repeat our seismic experiment is crucial. However, it is always a question of detectability versus repeatability. For marine seismic, there are several factors limiting the repeatability: Weather conditions, positioning of sources and receivers and so on. I will discuss recent improvements in both acquisition and processing methods over the last decade. It is well known that repeated 3D seismic data is the most accurate tool for reservoir monitoring purposes. However, several examples show that 2D seismic data may be used for monitoring purposes despite lower repeatability. I will use examples from an underground blow out in the North Sea, and repeated 2D seismic lines acquired before and after the Tohoku earthquake in 2011 to illustrate this. A major challenge when using repeated 2D seismic for subsurface monitoring purposes is the lack of 3D calibration points and significantly less amount of data. For marine seismic acquisition, feathering issues and crossline dip effects become more critical compared to 3D seismic acquisition. Furthermore, the uncertainties arising from a non-ideal 2D seismic acquisition are hard to assess, since the 3D subsurface geometry has not been mapped. One way to shed more light on this challenge is to use 3D time lapse seismic modeling testing various crossline dips or geometries. Other ways are to use alternative data sources, such as bathymetry, time lapse gravity or electromagnetic data. The end result for all time-lapse monitoring projects is an interpretation associated with uncertainties, and for the 2D case these uncertainties are often large. The purpose of this talk is to discuss how to reduces and control these uncertainties as much as possible.

Exposure to Radiofrequency Radiation Emitted from Common Mobile Phone Jammers Alters the Pattern of Muscle Contractions: an Animal Model Study.

PubMed

Rafati, A; Rahimi, S; Talebi, A; Soleimani, A; Haghani, M; Mortazavi, S M J

2015-09-01

The rapid growth of wireless communication technologies has caused public concerns regarding the biological effects of electromagnetic radiations on human health. Some early reports indicated a wide variety of non-thermal effects of electromagnetic radiation on amphibians such as the alterations of the pattern of muscle extractions. This study is aimed at investigating the effects of exposure to radiofrequency (RF) radiation emitted from mobile phone jammers on the pulse height of contractions, the time interval between two subsequent contractions and the latency period of frog's isolated gastrocnemius muscle after stimulation with single square pulses of 1V (1 Hz). Frogs were kept in plastic containers in a room. Animals in the jammer group were exposed to radiofrequency (RF) radiation emitted from a common Jammer at a distance of 1m from the jammer's antenna for 2 hours while the control frogs were only sham exposed. Then animals were sacrificed and isolated gastrocnemius muscles were exposed to on/off jammer radiation for 3 subsequent 10 minute intervals. Isolated gastrocnemius muscles were attached to the force transducer with a string. Using a PowerLab device (26-T), the pattern of muscular contractions was monitored after applying single square pulses of 1V (1 Hz) as stimuli. The findings of this study showed that the pulse height of muscle contractions could not be affected by the exposure to electromagnetic fields. However, the latency period was effectively altered in RF-exposed samples. However, none of the experiments could show an alteration in the time interval between two subsequent contractions after exposure to electromagnetic fields. These findings support early reports which indicated a wide variety of non-thermal effects of electromagnetic radiation on amphibians including the effects on the pattern of muscle extractions.

Sea-Ice Thickness Monitoring from Sensor Equipped Inuit Sleds

NASA Astrophysics Data System (ADS)

Rodwell, Shane; Jones, Bryn; Wilkinson, Jeremy

2013-04-01

A novel instrumentation package capable of measuring sea-ice thickness autonomously has been designed for long-term deployment upon the dog drawn sleds of the indigenous peoples of the Arctic. The device features a range of sensors that have been integrated with an electromagnetic induction device. These include a global positioning system, temperature sensor, tilt meter and accelerometer. Taken together, this system is able to provide accurate (+/-5cm) measurements of ice thickness with spatio-temporal resolution ranging from 1m to 5m every second. Autonomous data transmission capability is provided via GSM, inspired by the fact that many of the coastal communities in Greenland possess modern cell-phone infrastructure, enabling an inexpensive means of data-retrieval. Such data is essential in quantifying the sea-ice mass balance; given that existing satellite based systems are unable to measure ice-thickness directly. Field-campaign results from a prototype device, deployed in the North West of Greenland during three consecutive seasons, have demonstrated successful proof-of-concept when compared to data provided by ice mass balance (IMB) stations provided at fixed positions along the route of the sled. This project highlights not only the use of novel polar technology, but how opportunistic deployment using an existing roving platform (Inuit sledges) can provide economical, yet highly valuable, data for instrumentation development.

Progress on Pre-Stage Magnetic Coil to Enhance Helicon Mode Excitation and Data Acquisition Software on the Helicon Plasma Experiment (HPX)

NASA Astrophysics Data System (ADS)

Sherman, Justin; Azzari, Phillip; Crilly, P. B.; Duke-Tinson, Omar; James, Royce W.; Karama, Jackson; Page, E. J.; Schlank, Carter; Zuniga, Jonathan

2014-10-01

CGAPL is conducting small investigations in plasma physics and magneto-hydrodynamics buoy positioning. For data management, we are developing capability to analyze/digitize data with a National Instruments Data Acquisition board, 2 MS/s sampling rate (long time scale), and an Express Octopus card, 125 MS/s sampling rate (short scale). Sampling at 12 bits precision, we use LabVIEW as a programing language; GUIs will control variables in 1 or more concurrent runs and monitor of diagnostics. HPX utilizes high density (1013 cm3 up), low pressure (.01 T) Ar gas (fill pressure: on 104 mTorr order). Helicon/W Mode plasmas become a diagnostics test-bed for other investigations and a tool for future spacecraft propulsion devices. Plasmas created by directing energy into gas-filled Pyrex tube; power supply and matching box, up to 250 W power in 20-100 MHz frequencies, provide energy to ignite. Uniform magnetic field needed to reach the W-Mode. We employ an electromagnet to B-field while an acceleration coil positions plasma in vacuum chamber, facilitating analysis. Initial field requirements and accuracy calibration have been completed. Progress on development and implementation of probes and DAQ/GUI system will be reported. Supported by U.S. DEPS Grant [HEL-JTO] PRWJFY13.

Pantograph-catenary monitoring by means of fibre Bragg grating sensors: Results from tests in an underground line

NASA Astrophysics Data System (ADS)

Bocciolone, Marco; Bucca, Giuseppe; Collina, Andrea; Comolli, Lorenzo

2013-12-01

One of the most common way to collect the traction current needed for the underground vehicle operation is by using the pantograph-overhead line system. The periodically check of pantographs and overhead lines is important to assure the correct interaction between the two systems in terms of good current collection quality. The main diagnostic tools are the monitoring of the vertical force between the overhead line and the pantograph head, and the vertical acceleration on the pantograph head. The pantograph system works under high voltage (1500 V, DC, in our tests) and high electromagnetic disturbances are present. For this reason, traditional electrical sensors can be used only with particular precautions that complicate the measurement set up; fibre optic sensors, and in particular fibre Bragg grating (FBG) sensors, are particularly suitable for this application. In this paper, the application of the FBG sensors on a pantograph for the monitoring of underground pantograph-catenary system is presented. FBG sensors are used to measure both the contact force and the vertical acceleration of the pantograph head. The same measurements are also gathered with a traditional electrical system, allowing a comparison. The result is a very good agreement between electrical and optical measurements, except in particular frequency ranges where the different positioning of the sensors influences the output, limiting the comparison. Moreover, some interesting results on the dynamic behaviour of the pantograph and its interaction with the overhead line are presented. Finally, a method to point out the main defects on the overhead line is shown.

Controlled Source Electromagnetic Monitoring of Hydraulic Fracturing: Wellbore and Fluid Effects

NASA Astrophysics Data System (ADS)

Couchman, M. J.; Everett, M. E.

2017-12-01

As unconventional resources become increasingly important, we must tackle the issue of real-time monitoring of the efficiency of unconventional hydrocarbon extraction. Controlled Source Electromagnetics (CSEM) have been used primarily as a marine-based technique to monitor conventional oil bearing reservoirs with a strong resurgence the new millennium. Many of these studies revolving around detecting a thin resistive layer such as a reservoir at 1m - 3km depth. In these cases, the presence of the resistive layer is characterized by a jump in electric field amplitude recorded at the boundary between the layer and the host sediments. The lessons learned from these studies can be applied to terrestrial unconventional settings with appropriate modifications. The work shown here is a means develop methods which enable more reliable terrestrial CSEM monitoring of the flow of injected fluids associated with hydraulic fracturing of unconventional reservoirs and to detect subsurface fluids based on their CSEM signature and in turn, to infer the subsurface flow of electrically conductive injected fluids. The predictive model validated for various 1-D marine, and terrestrial cases focus on the mapping of fluid flow in from a horizontal wellbore in a uniform halfspace using an in-line Horizontal Electric Dipole (HED) with electric field amplitude recorded by an array of electric field sensors. The effect of the of the vertical and horizontal wellbores are documented taking into account the conductivity, size, and thickness of each wellbore. The fracturing fluids flow and conductivity are also taken into account throughout various stages of the fracturing process. In each case, the sensitivity at a location of the surface in-line electric field to a given resistive or conductive layer, due to a source is calculated.

Hydrogeological characterization of shallow-depth zone for CO2 injection and leak test at a CO2 environmental monitoring site in Korea

NASA Astrophysics Data System (ADS)

Lee, S. S.; Kim, T. W.; Kim, H. H.; Ha, S. W.; Jeon, W. T.; Lee, K. K.

2015-12-01

The main goal of the this study is to evaluate the importance of heterogeneities in controlling the field-scale transport of CO2 are originated from the CO2 injected at saturated zone below the water table for monitoring and prediction of CO2 leakage from a reservoir. Hydrogeological and geophysical data are collected to characterize the site, prior to conducting CO2 injection experiment at the CO2 environmental monitoring site at Eumseong, Korea. The geophysical data were acquired from borehole electromagnetic flowmeter tests, while the hydraulic data were obtained from pumping tests, slug tests, and falling head permeability tests. Total of 13 wells to perform hydraulic and geophysical test are established along groundwater flow direction in regular sequence, revealed by the results of borehole electromagnetic flowmeter test. The results of geophysical tests indicated that hydraulic gradient is not identical with the topographic gradient. Groundwater flows toward the uphill direction in the study area. Then, the hydraulic tests were conducted to identify the hydraulic properties of the study site. According to the results of pumping and slug tests at the study site, the hydraulic conductivity values show ranges between 4.75 x 10-5 cm/day and 9.74 x 10-5 cm/day. In addition, a portable multi-level sampling and monitoring packer device which remains inflated condition for a long period developed and used to isolate designated depths to identify vertical distribution of hydrogeological characteristics. Hydrogeological information obtained from this study will be used to decide the injection test interval of CO2-infused water and gaseous CO2. Acknowledgement: Financial support was provided by "R&D Project on Environmental Mangement of Geologic CO2 Storage" from the KEITI (Project Number: 2014001810003).

[Objectivized evaluation of surgeons exposure to radiofrequency electromagnetic fields -- in the context of exposure duration and Polish and new international requirements regarding workers protection].

PubMed

Karpowicz, Jolanta; Gryz, Krzysztof; Leszko, Wieslaw; Zradziński, Patryk

2013-01-01

Use of electro surgery units (ESU) in surgeries is linked with electromagnetic field emission, which is assessed according to the requirements of occupational health and safety legislation. Surgeons' exposure characteristics was monitored during 11 surgeries (proctectomy, patency of artery, hepatectomy, cystectomy, tonsilectomy, laparoscopy) by real time of monopolar ESU activity recorder. Investigations of root-mean-square value of electric and magnetic field strength was also performed at various modes of ESU operations during cutting (output power, 55-150 W; frequency, 330-445 kHz) and coagulating (40-240 W, 335-770 kHz). Statistical parameters of distribution of ESU operation over any 6-min periods (according to international requirements regarding protection against adverse thermal effects of electromagnetic field) were assessed. Electric field strength, measured 10 cm from the cable supplying an active electrode was 147-675 V/m during cutting and 297-558 V/m during coagulating; magnetic field strength was less than 0.2 A/m in both modes. Monitoring of ESUs showed the following ranges of their operation during surgeries 5-66% of time over starting 3 min of surgery, 3-40% over starting 6 min, and the distribution of their use over any 6-min periods 0-12% (median) / 7-43% (maximum value). The real operation time of ESUs ing surgeries was significantly shorter than that declared by workers. The distance of at least 15 cm between cables, connecting electrodes with generator and workers meets the requirements of the Polish legislation on permissible exposure limits. The assessment of localized exposure of the hand needs a detailed analysis of the SAR ratio distribution and further studies are required.

Identification of sewage leaks by active remote-sensing methods

NASA Astrophysics Data System (ADS)

Goldshleger, Naftaly; Basson, Uri

2016-04-01

The increasing length of sewage pipelines, and concomitant risk of leaks due to urban and industrial growth and development is exposing the surrounding land to contamination risk and environmental harm. It is therefore important to locate such leaks in a timely manner, to minimize the damage. Advances in active remote sensing Ground Penetrating Radar (GPR) and Frequency Domain Electromagnetic (FDEM) technologies was used to identify leaking potentially responsible for pollution and to identify minor spills before they cause widespread damage. This study focused on the development of these electromagnetic methods to replace conventional acoustic methods for the identification of leaks along sewage pipes. Electromagnetic methods provide an additional advantage in that they allow mapping of the fluid-transport system in the subsurface. Leak-detection systems using GPR and FDEM are not limited to large amounts of water, but enable detecting leaks of tens of liters per hour, because they can locate increases in environmental moisture content of only a few percentage along the pipes. The importance and uniqueness of this research lies in the development of practical tools to provide a snapshot and monitoring of the spatial changes in soil moisture content up to depths of about 3-4 m, in open and paved areas, at relatively low cost, in real time or close to real time. Spatial measurements performed using GPR and FDEM systems allow monitoring many tens of thousands of measurement points per hectare, thus providing a picture of the spatial situation along pipelines and the surrounding. The main purpose of this study was to develop a method for detecting sewage leaks using the above-proposed geophysical methods, since their contaminants can severely affect public health. We focused on identifying, locating and characterizing such leaks in sewage pipes in residential and industrial areas.

Monitoring electrical properties for improving the lithological and hydrological characterization of landslides

NASA Astrophysics Data System (ADS)

Malet, J. P.; Gance, J.; Lajaunie, M.; Gallistl, J.; Denchik, N.; Flores Orozco, A.; Ottowitz, D.; Supper, R.; Sailhac, P.; Gautier, S.; Schmutz, M.

2017-12-01

Imaging water flows in landslides is of critical importance as the distribution of pore-fluid pressures controls the dynamics (acceleration, deceleration) of the material. Detecting and imaging water is a difficult task, not only because of the complex topography and the small dimensions of the geological structures, but also because the landslide material consists of unsaturated porous and heterogeneous fractured media, leading to multi-scale water-flow properties. Further, these properties can change in time, in relation to temperature, rainfall and biological forcings. Electrical properties are relevant proxies of the sub-surface hydrological properties. In order to image water in landslide bodies, we propose to combine multi-frequency electrical and electromagnetic measurements using campaigns or permanent instruments, and surface/boreole investigations, installed on several unstable slopes in France. To evaluate the information gained from electrical properties for different geological conditions, we discuss electrical and electro-magnetic imaging results for data collected at four different landslides located in France (Super-Sauze and La Valette in the South East Alps, Lodève lin the southern border of the Massif Central Massif, and Séchilienne in the North French Alps). Time-lapse electrical DC resistivity observations, complex electrical conductivity (conduction and polarization/chargeability) measured by IP imaging methods, and controlled-source electromagnetic (CS-AMT) methods are discussed. Imaging results demonstrate an improved lithological characterization of the landslide structures (delineation of the sliding planes, identification of the fractures, discrimination of clay lenses with enhanced resolution); further, water infiltration within the soil matrix and/or the fractures is discriminated allowing better modelling of the hydrological regime of the landslides at the slope scale. This research is conducted in the frame of the project HYDROSLIDE - Hydrogeophysical Monitoring of Clay-Rich Landslides funded by the Austrian Science Fund (FWF) and the French Research Agency (ANR).

Recent Stirling Conversion Technology Developments and Operational Measurements at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Oriti, Salvatore M.; Schifer, Nicholas A.

2010-01-01

In support of the Advanced Stirling Radioisotope Generator (ASRG) project and other potential applications, NASA Glenn Research Center (GRC) has initiated convertor technology development efforts in the areas of acoustic emission, electromagnetic field mitigation, thermoacoustic Stirling conversion, and multiple-cylinder alpha arrangements of Stirling machines. The acoustic emission measurement effort was developed as a health monitoring metric for several Stirling convertors undergoing life testing. While accelerometers have been used in the past to monitor dynamic signature, the acoustic sensors were chosen to monitor cycle events, such gas bearing operation. Several electromagnetic interference (EMI) experiments were performed on a pair of Advanced Stirling Convertors (ASC). These tests demonstrated that a simple bucking coil was capable of reducing the alternating current (ac) magnetic field below the ASRG system specification. The thermoacoustic Stirling concept eliminates the displacer typically found in Stirling machines by making use of the pressure oscillations of a traveling acoustic wave. A 100 W-class thermoacoustic Stirling prototype manufactured by Northrop Grumman Space and Technology was received and tested. Another thermoacoustic prototype designed and fabricated by Sunpower, Inc., will be tested in the near future. A four cylinder free piston alpha prototype convertor was received from Sunpower, Inc. and has been tested at GRC. This hardware was used as a proof of concept to validate thermodynamic models and demonstrate stable operation of multiple-cylinder free-piston Stirling conversion. This paper will discuss each of these activities and the results they produced.

A non-asymptotic homogenization theory for periodic electromagnetic structures

PubMed Central

Tsukerman, Igor; Markel, Vadim A.

2014-01-01

Homogenization of electromagnetic periodic composites is treated as a two-scale problem and solved by approximating the fields on both scales with eigenmodes that satisfy Maxwell's equations and boundary conditions as accurately as possible. Built into this homogenization methodology is an error indicator whose value characterizes the accuracy of homogenization. The proposed theory allows one to define not only bulk, but also position-dependent material parameters (e.g. in proximity to a physical boundary) and to quantify the trade-off between the accuracy of homogenization and its range of applicability to various illumination conditions. PMID:25104912

EM Modelling of RF Propagation Through Plasma Plumes

NASA Astrophysics Data System (ADS)

Pandolfo, L.; Bandinelli, M.; Araque Quijano, J. L.; Vecchi, G.; Pawlak, H.; Marliani, F.

2012-05-01

Electric propulsion is a commercially attractive solution for attitude and position control of geostationary satellites. Hall-effect ion thrusters generate a localized plasma flow in the surrounding of the satellite, whose impact on the communication system needs to be qualitatively and quantitatively assessed. An electromagnetic modelling tool has been developed and integrated into the Antenna Design Framework- ElectroMagnetic Satellite (ADF-EMS). The system is able to guide the user from the plume definition phases through plume installation and simulation. A validation activity has been carried out and the system has been applied to the plume modulation analysis of SGEO/Hispasat mission.

Solar tracker motor having a fixed caliper and a translating caliper each with an electromagnetic brake system

DOEpatents

Rau, Scott James

2013-01-29

Concepts and technologies described herein provide for an accurate and cost-effective method for rotating a solar array disk for tracking the movement of the sun. According to various aspects, a motor includes a fixed caliper and a translating caliper positioned adjacent to one another. Electromagnetically controlled brakes on the translating caliper grip the solar array disk while adjacent, but spaced apart, electromagnets on the fixed caliper and the translating caliper are energized to create an attractive force that pulls the translating caliper with the solar array disk toward the fixed caliper. After reaching the fixed caliper, brakes on the fixed caliper are engaged with the disk, brakes on the translating caliper are released from the disk, and the translating caliper is pushed back to the starting location where the process repeats until the desired rotation is completed.

Estimation of electromagnetic dosimetric values from non-ionizing radiofrequency fields in an indoor commercial airplane environment.

PubMed

Aguirre, Erik; Arpón, Javier; Azpilicueta, Leire; López, Peio; de Miguel, Silvia; Ramos, Victoria; Falcone, Francisco

2014-12-01

In this article, the impact of topology as well as morphology of a complex indoor environment such as a commercial aircraft in the estimation of dosimetric assessment is presented. By means of an in-house developed deterministic 3D ray-launching code, estimation of electric field amplitude as a function of position for the complete volume of a commercial passenger airplane is obtained. Estimation of electromagnetic field exposure in this environment is challenging, due to the complexity and size of the scenario, as well as to the large metallic content, giving rise to strong multipath components. By performing the calculation with a deterministic technique, the complete scenario can be considered with an optimized balance between accuracy and computational cost. The proposed method can aid in the assessment of electromagnetic dosimetry in the future deployment of embarked wireless systems in commercial aircraft.

Biological Effects of Electromagnetic Fields

DTIC Science & Technology

2006-11-27

cerebral activity reflected by high levels of c-Fos- positive neurons in certain brain areas (14). The brain tissue of seizure proneness can be...radiation triggers seizures and increases cerebral c-Fos positivity in rats pretreated with subconvulsive doses of...psychiatric, cardiovascular or neurological diseases); or have a cardiac or cerebral pacemaker. They have no history of head, eye or thorax injury involving

A motionless actuation system for magnetic shape memory devices

NASA Astrophysics Data System (ADS)

Armstrong, Andrew; Finn, Kevin; Hobza, Anthony; Lindquist, Paul; Rafla, Nader; Müllner, Peter

2017-10-01

Ni-Mn-Ga is a Magnetic Shape Memory (MSM) alloy that changes shape in response to a variable magnetic field. We can intentionally manipulate the shape of the material to function as an actuator, and the material can thus replace complicated small electromechanical systems. In previous work, a very simple and precise solid-state micropump was developed, but a mechanical rotation was required to translate the position of the magnetic field. This mechanical rotation defeats the purpose of the motionless solid-state device. Here we present a solid-state electromagnetic driver to linearly progress the position of the applied magnetic field and the associated shrinkage. The generated magnetic field was focused at either of two pole pieces, providing a mechanism for moving the localized shrinkage in the MSM element. We confirmed that our driver has sufficient strength to actuate the MSM element using optical microscopy. We validated the whole design by comparing results obtained with finite element analysis with the experimentally measured flux density. This drive system serves as a possible replacement to the mechanical rotation of the magnetic field by using a multi-pole electromagnet that sweeps the magnetic field across the MSM micropump element, solid-state switching the current to each pole piece in the multi-pole electromagnet.

A novel in vivo method for lung segment movement tracking

NASA Astrophysics Data System (ADS)

Leira, H. O.; Tangen, G. A.; Hofstad, E. F.; Langø, T.; Amundsen, T.

2012-02-01

Knowledge about lung movement in health and disease is sparse. Current evaluation methods, such as CT, MRI and external view have significant limitations. To study respiratory movement for image guided tumour diagnostics and respiratory physiology, we needed a method that overcomes these limitations. We fitted balloon catheters with electromagnetic sensors, and placed them in lung lobes of ventilated pigs. The sensors sensed their position at 40 Hz in an electromagnetic tracking field with a precision of ∼0.5 mm. The method was evaluated by recording sensor movement in different body positions and at different tidal volumes. No ‘gold standard’ exists for lung segment tracking, so our results were compared to ‘common knowledge’. The sensors were easily placed, showed no clinically relevant position drift and yielded sub-millimetre accuracy. Our measurements fit ‘common knowledge’, as increased ventilation volume increased respiratory movement, and the right lung moved significantly less in the right than the left lateral position. The novel method for tracking lung segment movements during respiration was easy to implement and yielded high spatial and temporal resolution, and the equipment parts are reusable. It is easy to implement as a research tool for lung physiology, navigated bronchoscopy and radiation therapy.

Fiber-optic security monitoring sensor

NASA Astrophysics Data System (ADS)

Englund, Marja; Ipatti, Ari; Karioja, Pentti

1997-09-01

In security monitoring, fiber-optic sensors are advantageous because strong and rugged optical fibers are thin, light, flexible and immune to electromagnetic interference. Optical fibers packaged into cables, such as, building and underground cables, can be used to detect even slightest disturbances, movements, vibrations, pressure changes and impacts along their entire length. When running an optical cable around a structure, and when using speckle pattern recognition technique for alarm monitoring, the distributed monitoring of the structure is possible. The sensing cable can be strung along fences, buried underground, embedded into concrete, mounted on walls, floors and ceilings, or wrapped around the specific components. In this paper, a fiber-optic security monitoring sensor based on speckle pattern monitoring is described. The description of the measuring method and the results of the experimental fiber installations are given. The applicability of embedded and surface mounted fibers to monitor the pressure and impact induced vibrations of fences and concrete structures as well as the loosening of critical parts in a power plant machinery were demonstrated in field and laboratory conditions. The experiences related to the applications and optical cable types are also discussed.

Fiber optic security monitoring sensor

NASA Astrophysics Data System (ADS)

Englund, Marja; Ipatti, Ari; Karioja, Pentti

1997-09-01

In security monitoring, fiber-optic sensors are advantageous because strong and rugged optical fibers are thin, light, flexible and immune to electromagnetic interference. Optical fibers packaged into cables, such as, building and underground cables, can be used to detect even slightest disturbances, movements, vibrations, pressure changes and impacts along their entire length. When running an optical cable around a structure, and when using speckle pattern recognition technique for alarm monitoring, the distributed monitoring of the structure is possible. The sensing cable can be strung along fences, buried underground, embedded into concrete, mounted on walls, floors and ceilings, or wrapped around the specific components. In this paper, a fiber-optic security monitoring sensor based on speckle pattern monitoring is described. The description of the measuring method and the results of the experimental fiber installations are given. The applicability of embedded and surface mounted fibers to monitor the pressure and impact induced vibrations of fences and concrete structures as well as the loosening of critical parts in a power plant machinery were demonstrated in field and laboratory conditions. The experiences related to the applications and optical cable types are also discussed.

Electromagnetic Navigation Diagnostic Bronchoscopy

PubMed Central

Gildea, Thomas R.; Mazzone, Peter J.; Karnak, Demet; Meziane, Moulay; Mehta, Atul C.

2006-01-01

Rationale: Electromagnetic navigation bronchoscopy using superDimension/Bronchus System is a novel method to increase diagnostic yield of peripheral and mediastinal lung lesions. Objectives: A prospective, open label, single-center, pilot study was conducted to determine the ability of electromagnetic navigation bronchoscopy to sample peripheral lung lesions and mediastinal lymph nodes with standard bronchoscopic instruments and demonstrate safety. Methods: Electromagnetic navigation bronchoscopy was performed using the superDimension/Bronchus system consisting of electromagnetic board, position sensor encapsulated in the tip of a steerable probe, extended working channel, and real-time reconstruction of previously acquired multiplanar computed tomography images. The final distance of the steerable probe to lesion, expected error based on the actual and virtual markers, and procedure yield was gathered. Measurements: 60 subjects were enrolled between December 2004 and September 2005. Mean navigation times were 7 ± 6 min and 2 ± 2 min for peripheral lesions and lymph nodes, respectively. The steerable probe tip was navigated to the target lung area in all cases. The mean peripheral lesions and lymph nodes size was 22.8 ± 12.6 mm and 28.1 ± 12.8 mm. Yield was determined by results obtained during the bronchoscopy per patient. Results: The yield/procedure was 74% and 100% for peripheral lesions and lymph nodes, respectively. A diagnosis was obtained in 80.3% of bronchoscopic procedures. A definitive diagnosis of lung malignancy was made in 74.4% of subjects. Pneumothorax occurred in two subjects. Conclusion: Electromagnetic navigation bronchoscopy is a safe method for sampling peripheral and mediastinal lesions with high diagnostic yield independent of lesion size and location. PMID:16873767

Electromagnetic versus electrical coupling of personal frequency modulation (FM) receivers to cochlear implant sound processors.

PubMed

Schafer, Erin C; Romine, Denise; Musgrave, Elizabeth; Momin, Sadaf; Huynh, Christy

2013-01-01

Previous research has suggested that electrically coupled frequency modulation (FM) systems substantially improved speech-recognition performance in noise in individuals with cochlear implants (CIs). However, there is limited evidence to support the use of electromagnetically coupled (neck loop) FM receivers with contemporary CI sound processors containing telecoils. The primary goal of this study was to compare speech-recognition performance in noise and subjective ratings of adolescents and adults using one of three contemporary CI sound processors coupled to electromagnetically and electrically coupled FM receivers from Oticon. A repeated-measures design was used to compare speech-recognition performance in noise and subjective ratings without and with the FM systems across three test sessions (Experiment 1) and to compare performance at different FM-gain settings (Experiment 2). Descriptive statistics were used in Experiment 3 to describe output differences measured through a CI sound processor. Experiment 1 included nine adolescents or adults with unilateral or bilateral Advanced Bionics Harmony (n = 3), Cochlear Nucleus 5 (n = 3), and MED-EL OPUS 2 (n = 3) CI sound processors. In Experiment 2, seven of the original nine participants were tested. In Experiment 3, electroacoustic output was measured from a Nucleus 5 sound processor when coupled to the electromagnetically coupled Oticon Arc neck loop and electrically coupled Oticon R2. In Experiment 1, participants completed a field trial with each FM receiver and three test sessions that included speech-recognition performance in noise and a subjective rating scale. In Experiment 2, participants were tested in three receiver-gain conditions. Results in both experiments were analyzed using repeated-measures analysis of variance. Experiment 3 involved electroacoustic-test measures to determine the monitor-earphone output of the CI alone and CI coupled to the two FM receivers. The results in Experiment 1 suggested that both FM receivers provided significantly better speech-recognition performance in noise than the CI alone; however, the electromagnetically coupled receiver provided significantly better speech-recognition performance in noise and better ratings in some situations than the electrically coupled receiver when set to the same gain. In Experiment 2, the primary analysis suggested significantly better speech-recognition performance in noise for the neck-loop versus electrically coupled receiver, but a second analysis, using the best performance across gain settings for each device, revealed no significant differences between the two FM receivers. Experiment 3 revealed monitor-earphone output differences in the Nucleus 5 sound processor for the two FM receivers when set to the +8 setting used in Experiment 1 but equal output when the electrically coupled device was set to a +16 gain setting and the electromagnetically coupled device was set to the +8 gain setting. Individuals with contemporary sound processors may show more favorable speech-recognition performance in noise electromagnetically coupled FM systems (i.e., Oticon Arc), which is most likely related to the input processing and signal processing pathway within the CI sound processor for direct input versus telecoil input. Further research is warranted to replicate these findings with a larger sample size and to develop and validate a more objective approach to fitting FM systems to CI sound processors. American Academy of Audiology.

Radiant energy collector

DOEpatents

Winston, Roland

1977-01-11

An electromagnetic energy collection device is provided which does not require a solar tracking capability. It includes an energy receiver positioned between two side walls which reflect substantially all incident energy received over a predetermined included angle directly onto the energy receiver.

Position sensitive detection of neutrons in high radiation background field.

PubMed

Vavrik, D; Jakubek, J; Pospisil, S; Vacik, J

2014-01-01

We present the development of a high-resolution position sensitive device for detection of slow neutrons in the environment of extremely high γ and e(-) radiation background. We make use of a planar silicon pixelated (pixel size: 55 × 55 μm(2)) spectroscopic Timepix detector adapted for neutron detection utilizing very thin (10)B converter placed onto detector surface. We demonstrate that electromagnetic radiation background can be discriminated from the neutron signal utilizing the fact that each particle type produces characteristic ionization tracks in the pixelated detector. Particular tracks can be distinguished by their 2D shape (in the detector plane) and spectroscopic response using single event analysis. A Cd sheet served as thermal neutron stopper as well as intensive source of gamma rays and energetic electrons. Highly efficient discrimination was successful even at very low neutron to electromagnetic background ratio about 10(-4).

Effects of electric field and light polarization on the electromagnetically induced transparency in an impurity doped quantum ring

NASA Astrophysics Data System (ADS)

Bejan, D.; Stan, C.; Niculescu, E. C.

2018-01-01

We theoretically investigated the effects of the impurity position, in-plane electric field, intensity and polarization of the probe and control lasers on the electromagnetically induced transparency (EIT) in GaAs/GaAlAs disc shaped quantum ring. Our study reveals that, depending on the impurity position, the quantum system presents two specific configurations for the EIT occurrence even in the absence of the external electric field, i.e. ladder-configuration or V-configuration, and changes the configuration from ladder to V for specific electric field values. The polarization of the probe and control lasers plays a crucial role in obtaining a good transparency. The electric field controls the red-shift (blue-shift) of the transparency window and modifies its width. The system exhibits birefringence for the probe light in a limited interval of electric field values.

Positive and negative variations in capacitive images for given defects under varying experimental conditions

NASA Astrophysics Data System (ADS)

Li, Chen; Yin, Xiaokang; Li, Zhen; Li, Wei; Chen, Guoming

2018-04-01

Capacitive imaging (CI) technique is a novel electromagnetic NDE technique. The Quasi-static electromagnetic field from the carefully designed electrode pair will vary when the electrical properties of the sample change, leading to the possibility of imaging. It is observed that for a given specimen, the targeted features appear as different variations in capacitive images under different experimental conditions. In some cases, even opposite variations occur, which brings confusion to indication interpretation. It is thus thought interesting to embark on investigations into the cause and effects of the negative variation phenomenon. In this work, the positive and negative variations were first explained from the measurement sensitivity distribution perspective. This was then followed by a detailed analysis using finite element models in COMSOL. A parametric experimental study on a glass fiber composite plate with artificial defects was then carried out to investigate how the experimental conditions affect the variation.

Position sensitive detection of neutrons in high radiation background field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vavrik, D., E-mail: vavrik@itam.cas.cz; Institute of Theoretical and Applied Mechanics, Academy of Sciences of the Czech Republic, Prosecka 76, 190 00 Prague 9; Jakubek, J.

We present the development of a high-resolution position sensitive device for detection of slow neutrons in the environment of extremely high γ and e{sup −} radiation background. We make use of a planar silicon pixelated (pixel size: 55 × 55 μm{sup 2}) spectroscopic Timepix detector adapted for neutron detection utilizing very thin {sup 10}B converter placed onto detector surface. We demonstrate that electromagnetic radiation background can be discriminated from the neutron signal utilizing the fact that each particle type produces characteristic ionization tracks in the pixelated detector. Particular tracks can be distinguished by their 2D shape (in the detector plane)more » and spectroscopic response using single event analysis. A Cd sheet served as thermal neutron stopper as well as intensive source of gamma rays and energetic electrons. Highly efficient discrimination was successful even at very low neutron to electromagnetic background ratio about 10{sup −4}.« less

Remote Respiration Monitoring Using Ultra-wideband Microwave Sensor

NASA Astrophysics Data System (ADS)

Higashikatsuragi, Kenji; Nakahata, Youichiro; Matsunami, Isamu; Kajiwara, Akihiro

Impulse based ultra-wideband radio has lately attracted considerable attention as medical monitoring sensor since it is expected to measure bio-signals of a patient on a bed such as respiration rate and heartbeat with a remote non-contact approach. It is also friendly to the environment including the human body due to the very low electromagnetic energy emission. Using conventional ranging scheme, however, high speed A/D device should be required in order to detect the small respiratory displacement. This paper suggests a respiratory monitoring scheme where the respiration rate is measured by observing the variation of the path strength from the patient. Therefore, it does not require high speed A/D. It also makes possible to design the simultaneous monitoring of multiple patients in hospital beds, for example. In this paper the measurements were conducted for various scenarios and the feasibility is discussed.

Instrument specifications and geophysical records for airborne electromagnetic survey of parts of Iron, Baraga, and Dickson Counties, Michigan

USGS Publications Warehouse

Heran, William D.; Smith, Bruce D.

1980-01-01

The data presented herein is from an airborne electromagnetic INPUT* survey conducted by Geoterrex Limited of Canada for the U.S. Geological Survey. The survey area is located in the central part of the Upper Peninsula of Michigan, within parts of Iron, Baraga, and Dickinson Counties. The general area covered is between 46°00' and 46°30' latitude and 88°00' and 88°30' longitude (fig. 1).The INPUT survey was flown as part of a U.S. Geological Survey CUSMAP (Conterminous United States Mineral Appraisal Program) project focusing on the Iron River 2° quadrangle. The survey was flown in order to provide geophysical information which will aid in an integrated geological assessment of mineral potentials of this part of the Iron River 2° quadrangle. The flight line spacing was chosen to maximize the areal coverage without a loss of resolution of major lithologic and structural features.East-west flight lines were flown 400 feet above ground at 1/2 mile intervals. Aerial photos were used for navigation, and the flight path was recorded on continuous-strip film. A continuously recording total field ground magnetic station was used to monitor variations in the Earth's magnetic field. One north-south line was flown to provide a tie for the magnetic data, which was recorded simultaneously with the electromagnetic data by a sensor mounted in the tail of the aircraft. This report is one of two open-file reports. The map in the other report Heran and Smith (1980) shows locations of the fiducial points, the flight lines, preliminary locations of anomalies and conductive zones; all plotted on an air photomosaic. The latitude and longitude ticks marked on this map are only approximate due to distortion in air photos used to recover the flight line position. This map is preliminary and is not to be considered a final interpretation. The present report contains a description of the instrument specifications, a copy of the ground station magnetic data, and a record of the electromagnetic and magnetic data, with reference to the digital data of the flight records. The purpose of two reports is to make the analog and magnetic records available separate from the anomaly map. The following sections on the general description of the INPUT system are abridged from a typical interpretation report prepared by Geoterrex Limited of Ottawa, Canada for the U.S. Geological Survey.

Description and preliminary map, airborne electromagnetic survey of parts of Iron, Baraga, and Dickson counties, Michigan

USGS Publications Warehouse

Heran, William D.; Smith, Bruce D.

1980-01-01

The data presented herein is from an airborne electromagnetic INPUT* survey conducted by Geoterrex Limited of Canada for the U.S. Geological Survey. The survey area is located in the central part of the Upper Peninsula of Michigan, within parts of Iron, Baraga, and Dickinson Counties. The general area covered is between 46°00' and 46°30' latitude and 88°00' and 88°30' longitude (fig. 1).The INPUT survey was flown as part of a U.S. Geological Survey CUSMAP (Conterminous United States Mineral Appraisal Program) project focusing on the Iron River 2° quadrangle. The survey was flown in order to provide geophysical information which will aid in an integrated geological assessment of mineral potentials of this part of the Iron River 2 quadrangle. The flight-line spacing was chosen to maximize the aerial coverage without a loss of resolution of major lithologic and structural features. East-west flight lines were flown 400 feet above ground at 1/2-mile intervals. Aerial photos were used for navigation and the flight path was recorded on continuous-strip film. A continuously recording total field ground magnetic station was used to monitor variations in the Earth's magnetic field. One north-south line was flown to provide a tie for the magnetic data which was recorded simultaneously with the electromagnetic data by a sensor mounted in the tail of the aircraft. This report is one of two open-file reports. The map in the present report contains locations of the fiducial points, the flight lines, and preliminary locations of anomalies and conductive zones, all plotted on an air photomosaic. The latitude and longitude ticks marked on this map are only approximate due to distortion in air photos used to recover the flight line position. This map is preliminary and is not to be considered a final interpretation. The other report (Reran and Smith, 1980) contains a description of the instrument specifications, a copy of the ground station magnetic data, and a microfilm record of the electromagnetic and magnetic data, with reference to the digital data of the flight records. The purpose of two reports is to make the analog and digital records available separate from the anomaly map. The following sections on the general description of the INPUT system are abridged from a typical interpretation report prepared by Geoterrex Limited of Ottawa, Canada for the U.S. Geological Survey.

Radar detection of radiation-induced ionization in air

DOEpatents

Gopalsami, Nachappa; Heifetz, Alexander; Chien, Hual-Te; Liao, Shaolin; Koehl, Eugene R.; Raptis, Apostolos C.

2015-07-21

A millimeter wave measurement system has been developed for remote detection of airborne nuclear radiation, based on electromagnetic scattering from radiation-induced ionization in air. Specifically, methods of monitoring radiation-induced ionization of air have been investigated, and the ionized air has been identified as a source of millimeter wave radar reflection, which can be utilized to determine the size and strength of a radiation source.

Fiber-Optic Strain Sensors With Linear Characteristics

NASA Technical Reports Server (NTRS)

Egalon, Claudio O.; Rogowski, Robert S.

1993-01-01

Fiber-optic modal domain strain sensors having linear characteristics over wide range of strains proposed. Conceived in effort to improve older fiber-optic strain sensors. Linearity obtained by appropriate choice of design parameters. Pattern of light and dark areas at output end of optical fiber produced by interference between electromagnetic modes in which laser beam propagates in fiber. Photodetector monitors intensity at one point in pattern.

Armored Combat Vehicles Science and Technology Plan

DTIC Science & Technology

1982-11-01

APPLICATION OF SENSORS Investigate the seismic, acoustic, and electromagnetic signatures of military and intruder -type targets and the theoretical aspects...a prototype sampling system which has the capability to monitor ambieut air both outside and inside vehicles and provide an early warning to the crew...and through various processing modules provide automated functions for simultaneous tracking of targets and automitic recognition, 74 f’," SENSING

Textile composite processing science

NASA Technical Reports Server (NTRS)

Loos, Alfred C.; Hammond, Vincent H.; Kranbuehl, David E.; Hasko, Gregory H.

1993-01-01

A multi-dimensional model of the Resin Transfer Molding (RTM) process was developed for the prediction of the infiltration behavior of a resin into an anisotropic fiber preform. Frequency dependent electromagnetic sensing (FDEMS) was developed for in-situ monitoring of the RTM process. Flow visualization and mold filling experiments were conducted to verify sensor measurements and model predictions. Test results indicated good agreement between model predictions, sensor readings, and experimental data.

Borehole temperature variability at Hoher Sonnblick, Austria

NASA Astrophysics Data System (ADS)

Heinrich, Georg; Schöner, Wolfgang; Prinz, Rainer; Pfeiler, Stefan; Reisenhofer, Stefan; Riedl, Claudia

2016-04-01

The overarching aim of the project 'Atmosphere - permafrost relationship in the Austrian Alps - atmospheric extreme events and their relevance for the mean state of the active layer (ATMOperm)' is to improve the understanding of the impacts of atmospheric extreme events on the thermal state of the active layer using a combined measurement and modeling approach as the basis for a long-term monitoring strategy. For this purpose, the Sonnblick Observatory at the summit of Hoher Sonnblick (3106 m.a.s.l) is particularly well-suited due to its comprehensive long-term atmospheric and permafrost monitoring network (i.a. three 20 m deep boreholes since 2007). In ATMOperm, a robust and accurate permanent monitoring of active layer thickness at Hoher Sonnblick will be set up using innovative monitoring approaches by automated electrical resistivity tomography (ERT). The ERT monitoring is further supplemented by additional geophysical measurements such as ground penetrating radar, refraction seismic, electromagnetic induction and transient electromagnetics in order to optimally complement the gained ERT information. On the other hand, atmospheric energy fluxes over permafrost ground and their impact on the thermal state of permafrost and active layer thickness with a particular focus on atmospheric extreme events will be investigated based on physically-based permafrost modeling. For model evaluation, the borehole temperature records will play a key role and, therefore, an in-depth quality control of the borehole temperatures is an important prerequisite. In this study we will show preliminary results regarding the borehole temperature variability at Hoher Sonnblick with focus on the active layer. The borehole temperatures will be related to specific atmospheric conditions using the rich data set of atmospheric measurements of the site in order to detect potential errors in the borehole temperature measurements. Furthermore, we will evaluate the potential of filling gaps in the time series by cross checking all available information of the three boreholes. Furthermore, the already available ERT profiles will serve as additional information source improving the quality of the measured borehole temperatures.

Compilation of annual reports of the Navy ELF (Extremely Low Frequency) communications system ecological monitoring program. Volume 1: Tabs A-E

NASA Astrophysics Data System (ADS)

Anderson, M.; Bruhn, J.; Cattelino, P.; Janke, R.; Jurgensen, M.; Mroz, G.; Reed, E. J.; Trettin, C.

1984-07-01

A long-term program of studying ELF electromagnetic influences on ecosystems in northwestern Wisconsin and the Upper Peninsula of Michigan is being conducted. Selection of study sites, monitoring protocols, and analytical methods were initiated in 1982. Data collection was initiated in 1983. Progress is described for studying the terrestrial, aquatic, and wetland ecosystems for the 10 projects comprising the ecological monitoring program. The 10 projects contain Herbaceous Plant Cover and Tree Studies; Litter Decomposition and Microflora; The Effects of Exposing the Slime Mold Physarum polycephalum; Soil Amoeba; Soil and Litter Arthropoda and Earthworm Studies; Biological Studies on Pollinating Insects (Megachilid Bees); Small Vertebrates (Small Mammals and Nesting Birds); Aquatic Ecosystems; Wetland Studies; and Field Studies of Effects of ELF on Migrating Birds.

Sensor-model prediction, monitoring and in-situ control of liquid RTM advanced fiber architecture composite processing

NASA Technical Reports Server (NTRS)

Kranbuehl, D.; Kingsley, P.; Hart, S.; Loos, A.; Hasko, G.; Dexter, B.

1992-01-01

In-situ frequency dependent electromagnetic sensors (FDEMS) and the Loos resin transfer model have been used to select and control the processing properties of an epoxy resin during liquid pressure RTM impregnation and cure. Once correlated with viscosity and degree of cure the FDEMS sensor monitors and the RTM processing model predicts the reaction advancement of the resin, viscosity and the impregnation of the fabric. This provides a direct means for predicting, monitoring, and controlling the liquid RTM process in-situ in the mold throughout the fabrication process and the effects of time, temperature, vacuum and pressure. Most importantly, the FDEMS-sensor model system has been developed to make intelligent decisions, thereby automating the liquid RTM process and removing the need for operator direction.

High resolution, high sensitivity, dynamic distributed structural monitoring using optical frequency domain reflectometry

NASA Astrophysics Data System (ADS)

Kreger, Stephen T.; Sang, Alex K.; Garg, Naman; Michel, Julia

2013-05-01

Fiber-optic ultrasonic transducers are an important component of an active ultrasonic testing system for structural health monitoring. Fiber-optic transducers have several advantages such as small size, light weight, and immunity to electromagnetic interference that make them much more attractive than the current available piezoelectric transducers, especially as embedded and permanent transducers in active ultrasonic testing for structural health monitoring. In this paper, a distributed fiber-optic laser-ultrasound generation based on the ghost-mode of tilted fiber Bragg gratings is studied. The influences of the laser power and laser pulse duration on the laser-ultrasound generation are investigated. The results of this paper are helpful to understand the working principle of this laser-ultrasound method and improve the ultrasonic generation efficiency.

A tool to automatically analyze electromagnetic tracking data from high dose rate brachytherapy of breast cancer patients.

PubMed

Götz, Th I; Lahmer, G; Strnad, V; Bert, Ch; Hensel, B; Tomé, A M; Lang, E W

2017-01-01

During High Dose Rate Brachytherapy (HDR-BT) the spatial position of the radiation source inside catheters implanted into a female breast is determined via electromagnetic tracking (EMT). Dwell positions and dwell times of the radiation source are established, relative to the patient's anatomy, from an initial X-ray-CT-image. During the irradiation treatment, catheter displacements can occur due to patient movements. The current study develops an automatic analysis tool of EMT data sets recorded with a solenoid sensor to assure concordance of the source movement with the treatment plan. The tool combines machine learning techniques such as multi-dimensional scaling (MDS), ensemble empirical mode decomposition (EEMD), singular spectrum analysis (SSA) and particle filter (PF) to precisely detect and quantify any mismatch between the treatment plan and actual EMT measurements. We demonstrate that movement artifacts as well as technical signal distortions can be removed automatically and reliably, resulting in artifact-free reconstructed signals. This is a prerequisite for a highly accurate determination of any deviations of dwell positions from the treatment plan.

A tool to automatically analyze electromagnetic tracking data from high dose rate brachytherapy of breast cancer patients

PubMed Central

Lahmer, G.; Strnad, V.; Bert, Ch.; Hensel, B.; Tomé, A. M.; Lang, E. W.

2017-01-01

During High Dose Rate Brachytherapy (HDR-BT) the spatial position of the radiation source inside catheters implanted into a female breast is determined via electromagnetic tracking (EMT). Dwell positions and dwell times of the radiation source are established, relative to the patient’s anatomy, from an initial X-ray-CT-image. During the irradiation treatment, catheter displacements can occur due to patient movements. The current study develops an automatic analysis tool of EMT data sets recorded with a solenoid sensor to assure concordance of the source movement with the treatment plan. The tool combines machine learning techniques such as multi-dimensional scaling (MDS), ensemble empirical mode decomposition (EEMD), singular spectrum analysis (SSA) and particle filter (PF) to precisely detect and quantify any mismatch between the treatment plan and actual EMT measurements. We demonstrate that movement artifacts as well as technical signal distortions can be removed automatically and reliably, resulting in artifact-free reconstructed signals. This is a prerequisite for a highly accurate determination of any deviations of dwell positions from the treatment plan. PMID:28934238

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldstein, A.; Veres, P.; Burns, E.

We present the Fermi Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) observations of the LIGO binary black hole merger (BBH) event GW170104. No candidate electromagnetic counterparts was detected by either GBM or LAT. A detailed analysis of the GBM and LAT data over timescales from seconds to days covering the LIGO localization region is presented. The resulting ux upper bound from the GBM is (5.2{9.4) 10 -7 erg cm -2 s -1 in the 10-1000 keV range and from the LAT is (0.2{13) 10 -9 erg cm -2 s -1 in the 0.1{1 GeV range. We also describemore » the improvements to our automated pipelines and analysis techniques for searching for and characterizing the potential electromagnetic counterparts for future gravitational wave events from Advanced LIGO/VIRGO.« less

AC losses in horizontally parallel HTS tapes for possible wireless power transfer applications

NASA Astrophysics Data System (ADS)

Shen, Boyang; Geng, Jianzhao; Zhang, Xiuchang; Fu, Lin; Li, Chao; Zhang, Heng; Dong, Qihuan; Ma, Jun; Gawith, James; Coombs, T. A.

2017-12-01

This paper presents the concept of using horizontally parallel HTS tapes with AC loss study, and the investigation on possible wireless power transfer (WPT) applications. An example of three parallel HTS tapes was proposed, whose AC loss study was carried out both from experiment using electrical method; and simulation using 2D H-formulation on the FEM platform of COMSOL Multiphysics. The electromagnetic induction around the three parallel tapes was monitored using COMSOL simulation. The electromagnetic induction and AC losses generated by a conventional three turn coil was simulated as well, and then compared to the case of three parallel tapes with the same AC transport current. The analysis demonstrates that HTS parallel tapes could be potentially used into wireless power transfer systems, which could have lower total AC losses than conventional HTS coils.

Extra-corporeal blood access, sensing, and radiation methods and apparatuses

NASA Technical Reports Server (NTRS)

Castle, Kent D. (Inventor)

1993-01-01

The described invention is related to extra-corporeal blood access and radiation methods and apparatuses and, in particular, to subjecting flowing blood to energy in variety of forms, including radiation, electromagnetic force fields or atomic particles. It is directed to methods and apparatuses for accessing flowing blood and for subjecting the blood to electrical conductive, electrostatic or electromagnetic fields or for radiating the blood with some type of radiation, e.g., radio waves, ultrasonic or audio waves, microwaves, IR rays, visible light, UV radiation, x-rays, alpha, beta or gamma rays. An apparatus is employed which includes one or more access ports or windows for radiating blood and/or for sensing/analyzing blood. This invention is useful for killing viruses and bacteria in blood, monitoring blood for medical purposes, genetic modification of blood, and analyzing and/or treating blood components.

Effects of electromagnetic pulse on polydactyly of mouse fetuses.

PubMed

Yang, Ming-Juan; Liu, Jun-Ye; Wang, Ya-Feng; Lang, Hai-Yang; Miao, Xia; Zhang, Li-Yan; Zeng, Li-Hua; Guo, Guo-Zhen

2013-07-01

There is an increasing public concern regarding potential health impacts from electromagnetic radiation exposure. Embryonic development is sensitive to the external environment, and limb development is vital for life quality. To determine the effects of electromagnetic pulse (EMP) on polydactyly of mouse fetuses, pregnant mice were sham-exposed or exposed to EMP (400 kV/m with 400 pulses) from Days 7 to 10 of pregnancy (Day 0 = day of detection of vaginal plug). As a positive control, mice were treated with 5-bromodeoxyuridine on Days 9 and 10. On Days 11 or 18, the fetuses were isolated. Compared with the sham-exposed group, the group exposed to EMP had increased rates of polydactyly fetuses (5.1% vs. 0.6%, P < 0.05) and abnormal gene expression (22.2% vs. 2.8%, P < 0.05). Ectopic expression of Fgf4 was detected in the apical ectodermal ridge, whereas overexpression and ectopic expression of Shh were detected in the zone of polarizing activity of limbs in the EMP-exposed group and in the positive control group. However, expression of Gli3 decreased in mesenchyme cells in those two groups. The percentages of programmed cell death of limbs in EMP-exposed and positive control group were decreased (3.57% and 2.94%, respectively, P < 0.05, compared with 7.76% in sham-exposed group). In conclusion, polydactyly induced by EMP was accompanied by abnormal expression of the above-mentioned genes and decreased percentage of programmed cell death during limb development. Copyright © 2013 Elsevier Inc. All rights reserved.

Effects of short-duration electromagnetic radiation on early postnatal neurogenesis in rats: Fos and NADPH-d histochemical studies.

PubMed

Orendáčová, Judita; Orendáč, Martin; Mojžiš, Miroslav; Labun, Ján; Martončíková, Marcela; Saganová, Kamila; Lievajová, Kamila; Blaško, Juraj; Abdiová, Henrieta; Gálik, Ján; Račeková, Eniko

2011-11-01

The immediate effects of whole body electromagnetic radiation (EMR) were used to study postnatal neurogenesis in the subventricular zone (SVZ) and rostral migratory stream (RMS) of Wistar rats of both sexes. Newborn postnatal day 7 (P7) and young adult rats (P28) were exposed to pulsed electromagnetic fields (EMF) at a frequency of 2.45 GHz and mean power density of 2.8 mW/cm(2) for 2 h. Post-irradiation changes were studied using immunohistochemical localization of Fos and NADPH-d. We found that short-duration exposure induces increased Fos immunoreactivity selectively in cells of the SVZ of P7 and P28 rats. There were no Fos positive cells visible within the RMS of irradiated rats. These findings indicate that some differences exist in prerequisites of proliferating cells between the SVZ and RMS regardless of the age of the rats. Short-duration exposure also caused praecox maturation of NADPH-d positive cells within the RMS of P7 rats. The NADPH-d positive cells appeared several days earlier than in age-matched controls, and their number and morphology showed characteristics of adult rats. On the other hand, in the young adult P28 rats, EMR induced morphological signs typical of early postnatal age. These findings indicate that EMR causes age-related changes in the production of nitric oxide (NO), which may lead to different courses of the proliferation cascade in newborn and young adult neurogenesis. Copyright © 2010 Elsevier GmbH. All rights reserved.

Enabling aspects of fiber optic acoustic sensing in harsh environments

NASA Astrophysics Data System (ADS)

Saxena, Indu F.

2013-05-01

The advantages of optical fiber sensing in harsh electromagnetic as well as physical stress environments make them uniquely suited for structural health monitoring and non-destructive testing. In addition to aerospace applications they are making a strong footprint in geophysical monitoring and exploration applications for higher temperature and pressure environments, due to the high temperature resilience of fused silica glass sensors. Deeper oil searches and geothermal exploration and harvesting are possible with these novel capabilities. Progress in components and technologies that are enabling these systems to be fieldworthy are reviewed and emerging techniques summarized that could leapfrog the system performance and reliability.