Investigation of the Effects of Facility Background Pressure on the Performance and Voltage-Current Characteristics of the High Voltage Hall Accelerator

NASA Technical Reports Server (NTRS)

Kamhawi, Hani; Huang, Wensheng; Haag, Thomas; Spektor, Rostislav

2014-01-01

The National Aeronautics and Space Administration (NASA) Science Mission Directorate In-Space Propulsion Technology office is sponsoring NASA Glenn Research Center to develop a 4 kW-class Hall thruster propulsion system for implementation in NASA science missions. A study was conducted to assess the impact of varying the facility background pressure on the High Voltage Hall Accelerator (HiVHAc) thruster performance and voltage-current characteristics. This present study evaluated the HiVHAc thruster performance in the lowest attainable background pressure condition at NASA GRC Vacuum Facility 5 to best simulate space-like conditions. Additional tests were performed at selected thruster operating conditions to investigate and elucidate the underlying physics that change during thruster operation at elevated facility background pressure. Tests were performed at background pressure conditions that are three and ten times higher than the lowest realized background pressure. Results indicated that the thruster discharge specific impulse and efficiency increased with elevated facility background pressure. The voltage-current profiles indicated a narrower stable operating region with increased background pressure. Experimental observations of the thruster operation indicated that increasing the facility background pressure shifted the ionization and acceleration zones upstream towards the thruster's anode. Future tests of the HiVHAc thruster are planned at background pressure conditions that are expected to be two to three times lower than what was achieved during this test campaign. These tests will not only assess the impact of reduced facility background pressure on thruster performance, voltage-current characteristics, and plume properties; but will also attempt to quantify the magnitude of the ionization and acceleration zones upstream shifting as a function of increased background pressure.

Energy transport towards magnetosphere: current background and perspectives

NASA Astrophysics Data System (ADS)

Savin, Sergey; Zelenyi, Lev

On the background of rising number of multi-scale magnetospheric constellations of satellites (e.g. MMS, ROY, SCOPE etc.), we discuss realistic options for the future experimental efforts in the current international framework. Now space weather predictions require cross-scale (i.e. multi-point) and micro-scale (down to the electron inertial length and gyroradius, i.e. few km and 0.1 s) measurements, which should facilitate the fundamental turbulence explorations impacting e.g. fusion and astrophysical tasks. Both ROY and SCOPE could provide 4-6 space-craft under wide international collaboration. For SCOPE near-equatorial plane is the region for the multi-scale studies, while ROY will start from high latitudes and finish at the intermediate and, hopefully, low ones. We suggest a new strategy for the correlated measurements instead of a multi-tetrahedron configuration: -place spacecraft along magnetospheric boundaries: magne-topause, neutral sheet, bow shock et. instead of tetrahedron Cluster-like configuration trying to get the multi-scale measurements along the natural boundaries; -monitor the processes along the streamlines in magnetosheath; -use extra 2-8 nano/ pico-satellites for campaigns of the multi-spacecraft explorations, -utilize multi-frequency radio-tomography for monitoring of the inter-spacecraft processes Both SCOPE and ROY launchers have respective payload resources, which, with the respective international cooperation, should provide a new step in the magnetospheric plasma explorations.

Spectral feature characterization methods for blood stain detection in crime scene backgrounds

NASA Astrophysics Data System (ADS)

Yang, Jie; Mathew, Jobin J.; Dube, Roger R.; Messinger, David W.

2016-05-01

Blood stains are one of the most important types of evidence for forensic investigation. They contain valuable DNA information, and the pattern of the stains can suggest specifics about the nature of the violence that transpired at the scene. Blood spectral signatures containing unique reflectance or absorption features are important both for forensic on-site investigation and laboratory testing. They can be used for target detection and identification applied to crime scene hyperspectral imagery, and also be utilized to analyze the spectral variation of blood on various backgrounds. Non-blood stains often mislead the detection and can generate false alarms at a real crime scene, especially for dark and red backgrounds. This paper measured the reflectance of liquid blood and 9 kinds of non-blood samples in the range of 350 nm - 2500 nm in various crime scene backgrounds, such as pure samples contained in petri dish with various thicknesses, mixed samples with different colors and materials of fabrics, and mixed samples with wood, all of which are examined to provide sub-visual evidence for detecting and recognizing blood from non-blood samples in a realistic crime scene. The spectral difference between blood and non-blood samples are examined and spectral features such as "peaks" and "depths" of reflectance are selected. Two blood stain detection methods are proposed in this paper. The first method uses index to denote the ratio of "depth" minus "peak" over"depth" add"peak" within a wavelength range of the reflectance spectrum. The second method uses relative band depth of the selected wavelength ranges of the reflectance spectrum. Results show that the index method is able to discriminate blood from non-blood samples in most tested crime scene backgrounds, but is not able to detect it from black felt. Whereas the relative band depth method is able to discriminate blood from non-blood samples on all of the tested background material types and colors.

On-line Monitoring Device for High-voltage Switch Cabinet Partial Discharge Based on Pulse Current Method

NASA Astrophysics Data System (ADS)

Y Tao, S.; Zhang, X. Z.; Cai, H. W.; Li, P.; Feng, Y.; Zhang, T. C.; Li, J.; Wang, W. S.; Zhang, X. K.

2017-12-01

The pulse current method for partial discharge detection is generally applied in type testing and other off-line tests of electrical equipment at delivery. After intensive analysis of the present situation and existing problems of partial discharge detection in switch cabinets, this paper designed the circuit principle and signal extraction method for partial discharge on-line detection based on a high-voltage presence indicating systems (VPIS), established a high voltage switch cabinet partial discharge on-line detection circuit based on the pulse current method, developed background software integrated with real-time monitoring, judging and analyzing functions, carried out a real discharge simulation test on a real-type partial discharge defect simulation platform of a 10KV switch cabinet, and verified the sensitivity and validity of the high-voltage switch cabinet partial discharge on-line monitoring device based on the pulse current method. The study presented in this paper is of great significance for switch cabinet maintenance and theoretical study on pulse current method on-line detection, and has provided a good implementation method for partial discharge on-line monitoring devices for 10KV distribution network equipment.

The Pedestrian Detection Method Using an Extension Background Subtraction about the Driving Safety Support Systems

NASA Astrophysics Data System (ADS)

Muranaka, Noriaki; Date, Kei; Tokumaru, Masataka; Imanishi, Shigeru

In recent years, the traffic accident occurs frequently with explosion of traffic density. Therefore, we think that the safe and comfortable transportation system to defend the pedestrian who is the traffic weak is necessary. First, we detect and recognize the pedestrian (the crossing person) by the image processing. Next, we inform all the drivers of the right or left turn that the pedestrian exists by the sound and the image and so on. By prompting a driver to do safe driving in this way, the accident to the pedestrian can decrease. In this paper, we are using a background subtraction method for the movement detection of the movement object. In the background subtraction method, the update method in the background was important, and as for the conventional way, the threshold values of the subtraction processing and background update were identical. That is, the mixing rate of the input image and the background image of the background update was a fixation value, and the fine tuning which corresponded to the environment change of the weather was difficult. Therefore, we propose the update method of the background image that the estimated mistake is difficult to be amplified. We experiment and examines in the comparison about five cases of sunshine, cloudy, evening, rain, sunlight change, except night. This technique can set separately the threshold values of the subtraction processing and background update processing which suited the environmental condition of the weather and so on. Therefore, the fine tuning becomes possible freely in the mixing rate of the input image and the background image of the background update. Because the setting of the parameter which suited an environmental condition becomes important to minimize mistaking percentage, we examine about the setting of a parameter.

Comparison of presbyopic additions determined by the fused cross-cylinder method using alternative target background colours.

PubMed

Wee, Sung-Hyun; Yu, Dong-Sik; Moon, Byeong-Yeon; Cho, Hyun Gug

2010-11-01

To compare and contrast standard and alternative versions of refractor head (phoropter)-based charts used to determine reading addition. Forty one presbyopic subjects aged between 42 and 60 years were tested. Tentative additions were determined using a red-green background letter chart, and 4 cross-grid charts (with white, red, green, or red-green backgrounds) which were used with the fused cross cylinder (FCC) method. The final addition for a 40 cm working distance was determined for each subject by subjectively adjusting the tentative additions. There were significant differences in the tentative additions obtained using the 5 methods (repeated measures ANOVA, p < 0.001). The mean differences between the tentative and final additions were <0.10 D and were not clinically meaningful, with the exception of the red-green letter test, and the red background in the FCC method. There were no significant differences between the tentative and final additions for the green background in the FCC method (p > 0.05). The intervals of the 95% limits of agreement were under ±0.50 D, and the narrowest interval (±0.26 D) was for the red-green background. The 3 FCC methods with a white, green, or red-green background provided a tentative addition close to the final addition. Compared with the other methods, the FCC method with the red-green background had a narrow range of error. Further, since this method combines the functions of both the fused cross-cylinder test and the duochrome test, it can be a useful technique for determining presbyopic additions. © 2010 The Authors. Ophthalmic and Physiological Optics © 2010 The College of Optometrists.

Subspace-based optimization method for inverse scattering problems with an inhomogeneous background medium

NASA Astrophysics Data System (ADS)

Chen, Xudong

2010-07-01

This paper proposes a version of the subspace-based optimization method to solve the inverse scattering problem with an inhomogeneous background medium where the known inhomogeneities are bounded in a finite domain. Although the background Green's function at each discrete point in the computational domain is not directly available in an inhomogeneous background scenario, the paper uses the finite element method to simultaneously obtain the Green's function at all discrete points. The essence of the subspace-based optimization method is that part of the contrast source is determined from the spectrum analysis without using any optimization, whereas the orthogonally complementary part is determined by solving a lower dimension optimization problem. This feature significantly speeds up the convergence of the algorithm and at the same time makes it robust against noise. Numerical simulations illustrate the efficacy of the proposed algorithm. The algorithm presented in this paper finds wide applications in nondestructive evaluation, such as through-wall imaging.

Detection methods for non-Gaussian gravitational wave stochastic backgrounds

NASA Astrophysics Data System (ADS)

Drasco, Steve; Flanagan, Éanna É.

2003-04-01

A gravitational wave stochastic background can be produced by a collection of independent gravitational wave events. There are two classes of such backgrounds, one for which the ratio of the average time between events to the average duration of an event is small (i.e., many events are on at once), and one for which the ratio is large. In the first case the signal is continuous, sounds something like a constant hiss, and has a Gaussian probability distribution. In the second case, the discontinuous or intermittent signal sounds something like popcorn popping, and is described by a non-Gaussian probability distribution. In this paper we address the issue of finding an optimal detection method for such a non-Gaussian background. As a first step, we examine the idealized situation in which the event durations are short compared to the detector sampling time, so that the time structure of the events cannot be resolved, and we assume white, Gaussian noise in two collocated, aligned detectors. For this situation we derive an appropriate version of the maximum likelihood detection statistic. We compare the performance of this statistic to that of the standard cross-correlation statistic both analytically and with Monte Carlo simulations. In general the maximum likelihood statistic performs better than the cross-correlation statistic when the stochastic background is sufficiently non-Gaussian, resulting in a gain factor in the minimum gravitational-wave energy density necessary for detection. This gain factor ranges roughly between 1 and 3, depending on the duty cycle of the background, for realistic observing times and signal strengths for both ground and space based detectors. The computational cost of the statistic, although significantly greater than that of the cross-correlation statistic, is not unreasonable. Before the statistic can be used in practice with real detector data, further work is required to generalize our analysis to accommodate separated, misaligned

A statistical, task-based evaluation method for three-dimensional x-ray breast imaging systems using variable-background phantoms

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

Park, Subok; Jennings, Robert; Liu Haimo

Purpose: For the last few years, development and optimization of three-dimensional (3D) x-ray breast imaging systems, such as digital breast tomosynthesis (DBT) and computed tomography, have drawn much attention from the medical imaging community, either academia or industry. However, there is still much room for understanding how to best optimize and evaluate the devices over a large space of many different system parameters and geometries. Current evaluation methods, which work well for 2D systems, do not incorporate the depth information from the 3D imaging systems. Therefore, it is critical to develop a statistically sound evaluation method to investigate the usefulnessmore » of inclusion of depth and background-variability information into the assessment and optimization of the 3D systems. Methods: In this paper, we present a mathematical framework for a statistical assessment of planar and 3D x-ray breast imaging systems. Our method is based on statistical decision theory, in particular, making use of the ideal linear observer called the Hotelling observer. We also present a physical phantom that consists of spheres of different sizes and materials for producing an ensemble of randomly varying backgrounds to be imaged for a given patient class. Lastly, we demonstrate our evaluation method in comparing laboratory mammography and three-angle DBT systems for signal detection tasks using the phantom's projection data. We compare the variable phantom case to that of a phantom of the same dimensions filled with water, which we call the uniform phantom, based on the performance of the Hotelling observer as a function of signal size and intensity. Results: Detectability trends calculated using the variable and uniform phantom methods are different from each other for both mammography and DBT systems. Conclusions: Our results indicate that measuring the system's detection performance with consideration of background variability may lead to differences in system

getimages: Background derivation and image flattening method

NASA Astrophysics Data System (ADS)

Men'shchikov, Alexander

2017-05-01

getimages performs background derivation and image flattening for high-resolution images obtained with space observatories. It is based on median filtering with sliding windows corresponding to a range of spatial scales from the observational beam size up to a maximum structure width X. The latter is a single free parameter of getimages that can be evaluated manually from the observed image. The median filtering algorithm provides a background image for structures of all widths below X. The same median filtering procedure applied to an image of standard deviations derived from a background-subtracted image results in a flattening image. Finally, a flattened image is computed by dividing the background-subtracted by the flattening image. Standard deviations in the flattened image are now uniform outside sources and filaments. Detecting structures in such radically simplified images results in much cleaner extractions that are more complete and reliable. getimages also reduces various observational and map-making artifacts and equalizes noise levels between independent tiles of mosaicked images. The code (a Bash script) uses FORTRAN utilities from getsources (ascl:1507.014), which must be installed.

METHOD OF PEAK CURRENT MEASUREMENT

DOEpatents

Baker, G.E.

1959-01-20

The measurement and recording of peak electrical currents are described, and a method for utilizing the magnetic field of the current to erase a portion of an alternating constant frequency and amplitude signal from a magnetic mediums such as a magnetic tapes is presented. A portion of the flux from the current carrying conductor is concentrated into a magnetic path of defined area on the tape. After the current has been recorded, the tape is played back. The amplitude of the signal from the portion of the tape immediately adjacent the defined flux area and the amplitude of the signal from the portion of the tape within the area are compared with the amplitude of the signal from an unerased portion of the tape to determine the percentage of signal erasure, and thereby obtain the peak value of currents flowing in the conductor.

A novel method to remove GPR background noise based on the similarity of non-neighboring regions

NASA Astrophysics Data System (ADS)

Montiel-Zafra, V.; Canadas-Quesada, F. J.; Vera-Candeas, P.; Ruiz-Reyes, N.; Rey, J.; Martinez, J.

2017-09-01

Ground penetrating radar (GPR) is a non-destructive technique that has been widely used in many areas of research, such as landmine detection or subsurface anomalies, where it is required to locate targets embedded within a background medium. One of the major challenges in the research of GPR data remains the improvement of the image quality of stone materials by means of detection of true anisotropies since most of the errors are caused by an incorrect interpretation by the users. However, it is complicated due to the interference of the horizontal background noise, e.g., the air-ground interface, that reduces the high-resolution quality of radargrams. Thus, weak or deep anisotropies are often masked by this type of noise. In order to remove the background noise obtained by GPR, this work proposes a novel background removal method assuming that the horizontal noise shows repetitive two-dimensional regions along the movement of the GPR antenna. Specifically, the proposed method, based on the non-local similarity of regions over the distance, computes similarities between different regions of the same depth in order to identify most repetitive regions using a criterion to avoid closer regions. Evaluations are performed using a set of synthetic and real GPR data. Experimental results show that the proposed method obtains promising results compared to the classic background removal techniques and the most recently published background removal methods.

Enhanced low-noise gain from InAs avalanche photodiodes with reduced dark current and background doping

NASA Astrophysics Data System (ADS)

Maddox, S. J.; Sun, W.; Lu, Z.; Nair, H. P.; Campbell, J. C.; Bank, S. R.

2012-10-01

We reduced the room temperature dark current in an InAs avalanche photodiode by increasing the p-type contact doping, resulting in an increased energetic barrier to minority electron injection into the p-region, which is a significant source of dark current at room temperature. In addition, by improving the molecular beam epitaxy growth conditions, we reduced the background doping concentration and realized depletion widths as wide as 5 μm at reverse biases as low as 1.5 V. These improvements culminated in low-noise InAs avalanche photodiodes exhibiting a room temperature multiplication gain of ˜80, at a record low reverse bias of 12 V.

A new background subtraction method for energy dispersive X-ray fluorescence spectra using a cubic spline interpolation

NASA Astrophysics Data System (ADS)

Yi, Longtao; Liu, Zhiguo; Wang, Kai; Chen, Man; Peng, Shiqi; Zhao, Weigang; He, Jialin; Zhao, Guangcui

2015-03-01

A new method is presented to subtract the background from the energy dispersive X-ray fluorescence (EDXRF) spectrum using a cubic spline interpolation. To accurately obtain interpolation nodes, a smooth fitting and a set of discriminant formulations were adopted. From these interpolation nodes, the background is estimated by a calculated cubic spline function. The method has been tested on spectra measured from a coin and an oil painting using a confocal MXRF setup. In addition, the method has been tested on an existing sample spectrum. The result confirms that the method can properly subtract the background.

Fluorescence background removal method for biological Raman spectroscopy based on empirical mode decomposition.

PubMed

Leon-Bejarano, Maritza; Dorantes-Mendez, Guadalupe; Ramirez-Elias, Miguel; Mendez, Martin O; Alba, Alfonso; Rodriguez-Leyva, Ildefonso; Jimenez, M

2016-08-01

Raman spectroscopy of biological tissue presents fluorescence background, an undesirable effect that generates false Raman intensities. This paper proposes the application of the Empirical Mode Decomposition (EMD) method to baseline correction. EMD is a suitable approach since it is an adaptive signal processing method for nonlinear and non-stationary signal analysis that does not require parameters selection such as polynomial methods. EMD performance was assessed through synthetic Raman spectra with different signal to noise ratio (SNR). The correlation coefficient between synthetic Raman spectra and the recovered one after EMD denoising was higher than 0.92. Additionally, twenty Raman spectra from skin were used to evaluate EMD performance and the results were compared with Vancouver Raman algorithm (VRA). The comparison resulted in a mean square error (MSE) of 0.001554. High correlation coefficient using synthetic spectra and low MSE in the comparison between EMD and VRA suggest that EMD could be an effective method to remove fluorescence background in biological Raman spectra.

Advanced Practice Registered Nurses and Physician Assistants in Sleep Centers and Clinics: A Survey of Current Roles and Educational Background

PubMed Central

Colvin, Loretta; Cartwright, Ann; Collop, Nancy; Freedman, Neil; McLeod, Don; Weaver, Terri E.; Rogers, Ann E.

2014-01-01

Study Objectives: To survey Advanced Practice Registered Nurse (APRN) and Physician Assistant (PA) utilization, roles and educational background within the field of sleep medicine. Methods: Electronic surveys distributed to American Academy of Sleep Medicine (AASM) member centers and APRNs and PAs working within sleep centers and clinics. Results: Approximately 40% of responding AASM sleep centers reported utilizing APRNs or PAs in predominantly clinical roles. Of the APRNs and PAs surveyed, 95% reported responsibilities in sleep disordered breathing and more than 50% in insomnia and movement disorders. Most APRNs and PAs were prepared at the graduate level (89%), with sleep-specific education primarily through “on the job” training (86%). All APRNs surveyed were Nurse Practitioners (NPs), with approximately double the number of NPs compared to PAs. Conclusions: APRNs and PAs were reported in sleep centers at proportions similar to national estimates of NPs and PAs in physicians' offices. They report predominantly clinical roles, involving common sleep disorders. Given current predictions that the outpatient healthcare structure will change and the number of APRNs and PAs will increase, understanding the role and utilization of these professionals is necessary to plan for the future care of patients with sleep disorders. Surveyed APRNs and PAs reported a significant deficiency in formal and standardized sleep-specific education. Efforts to provide formal and standardized educational opportunities for APRNs and PAs that focus on their clinical roles within sleep centers could help fill a current educational gap. Citation: Colvin L, Cartwright Ann, Collop N, Freedman N, McLeod D, Weaver TE, Rogers AE. Advanced practice registered nurses and physician assistants in sleep centers and clinics: a survey of current roles and educational background. J Clin Sleep Med 2014;10(5):581-587. PMID:24812545

Optimization of Experimental Conditions of the Pulsed Current GTAW Parameters for Mechanical Properties of SDSS UNS S32760 Welds Based on the Taguchi Design Method

NASA Astrophysics Data System (ADS)

Yousefieh, M.; Shamanian, M.; Saatchi, A.

2012-09-01

Taguchi design method with L9 orthogonal array was implemented to optimize the pulsed current gas tungsten arc welding parameters for the hardness and the toughness of super duplex stainless steel (SDSS, UNS S32760) welds. In this regard, the hardness and the toughness were considered as performance characteristics. Pulse current, background current, % on time, and pulse frequency were chosen as main parameters. Each parameter was varied at three different levels. As a result of pooled analysis of variance, the pulse current is found to be the most significant factor for both the hardness and the toughness of SDSS welds by percentage contribution of 71.81 for hardness and 78.18 for toughness. The % on time (21.99%) and the background current (17.81%) had also the next most significant effect on the hardness and the toughness, respectively. The optimum conditions within the selected parameter values for hardness were found as the first level of pulse current (100 A), third level of background current (70 A), first level of % on time (40%), and first level of pulse frequency (1 Hz), while they were found as the second level of pulse current (120 A), second level of background current (60 A), second level of % on time (60%), and third level of pulse frequency (5 Hz) for toughness. The Taguchi method was found to be a promising tool to obtain the optimum conditions for such studies. Finally, in order to verify experimental results, confirmation tests were carried out at optimum working conditions. Under these conditions, there were good agreements between the predicted and the experimental results for the both hardness and toughness.

Current and future background ozone simulations for Mexico using a multi-scale regional climate modeling system

NASA Astrophysics Data System (ADS)

Lamb, B. K.; Gonzalez Abraham, R.; Avise, J. C.; Chung, S. H.; Salathe, E. P.; Zhang, Y.; Guenther, A. B.; Wiedinmyer, C.; Duhl, T.; Streets, D. G.

2013-05-01

Global change will clearly have a significant impact on the environment. Among the concerns for future air quality in North America, intercontinental transport of pollution has become increasingly important. In this study, we examined the effect of projected changes in Asian emissions and emissions from lightning and wildfires to produce ozone background concentrations within Mexico and the continental US. This provides a basis for developing an understanding of North American background levels and how they may change in the future. Meteorological fields were downscaled from the results of the ECHAM5 global climate model using the Weather Research Forecast (WRF) model. Two nested domains were employed, one covering most of the Northern Hemisphere from eastern Asia to North America using 220 km grid cells (semi-hemispheric domain) and one covering the continental US and northern Mexico using 36 km grid cells. Meteorological results from WRF were used to drive the MEGAN biogenic emissions model, the SMOKE emissions processing tool, and the CMAQ chemical transport model to predict ozone concentrations for current (1995-2004) and future (2045-2054) summertime conditions. The MEGAN model was used to calculate biogenic emissions for all simulations. For the semi-hemispheric domain, year 2000 global emissions of gases (ozone precursors) from anthropogenic (outside of North America), natural, and biomass burning sources from the POET and EDGAR emission inventories were used. The global tabulation for black and organic carbon (BC and OC respectively) was obtained from Bond et al. (2004) For the future decade, the current emissions were projected to the year 2050 following the Intergovernmental Panel for Climate Change (IPCC) A1B emission scenario. Anthropogenic emissions from the US, Canada, and Mexico were omitted so that only global background concentrations, and local biogenic, wildfire, and lightning emissions were treated. In this paper, we focus on background ozone

Background-Modeling-Based Adaptive Prediction for Surveillance Video Coding.

PubMed

Zhang, Xianguo; Huang, Tiejun; Tian, Yonghong; Gao, Wen

2014-02-01

The exponential growth of surveillance videos presents an unprecedented challenge for high-efficiency surveillance video coding technology. Compared with the existing coding standards that were basically developed for generic videos, surveillance video coding should be designed to make the best use of the special characteristics of surveillance videos (e.g., relative static background). To do so, this paper first conducts two analyses on how to improve the background and foreground prediction efficiencies in surveillance video coding. Following the analysis results, we propose a background-modeling-based adaptive prediction (BMAP) method. In this method, all blocks to be encoded are firstly classified into three categories. Then, according to the category of each block, two novel inter predictions are selectively utilized, namely, the background reference prediction (BRP) that uses the background modeled from the original input frames as the long-term reference and the background difference prediction (BDP) that predicts the current data in the background difference domain. For background blocks, the BRP can effectively improve the prediction efficiency using the higher quality background as the reference; whereas for foreground-background-hybrid blocks, the BDP can provide a better reference after subtracting its background pixels. Experimental results show that the BMAP can achieve at least twice the compression ratio on surveillance videos as AVC (MPEG-4 Advanced Video Coding) high profile, yet with a slightly additional encoding complexity. Moreover, for the foreground coding performance, which is crucial to the subjective quality of moving objects in surveillance videos, BMAP also obtains remarkable gains over several state-of-the-art methods.

Use of an OSSE to Evaluate Background Error Covariances Estimated by the 'NMC Method'

NASA Technical Reports Server (NTRS)

Errico, Ronald M.; Prive, Nikki C.; Gu, Wei

2014-01-01

The NMC method has proven utility for prescribing approximate background-error covariances required by variational data assimilation systems. Here, untunedNMCmethod estimates are compared with explicitly determined error covariances produced within an OSSE context by exploiting availability of the true simulated states. Such a comparison provides insights into what kind of rescaling is required to render the NMC method estimates usable. It is shown that rescaling of variances and directional correlation lengths depends greatly on both pressure and latitude. In particular, some scaling coefficients appropriate in the Tropics are the reciprocal of those in the Extratropics. Also, the degree of dynamic balance is grossly overestimated by the NMC method. These results agree with previous examinations of the NMC method which used ensembles as an alternative for estimating background-error statistics.

Universal field matching in craniospinal irradiation by a background-dose gradient-optimized method.

PubMed

Traneus, Erik; Bizzocchi, Nicola; Fellin, Francesco; Rombi, Barbara; Farace, Paolo

2018-01-01

The gradient-optimized methods are overcoming the traditional feathering methods to plan field junctions in craniospinal irradiation. In this note, a new gradient-optimized technique, based on the use of a background dose, is described. Treatment planning was performed by RayStation (RaySearch Laboratories, Stockholm, Sweden) on the CT scans of a pediatric patient. Both proton (by pencil beam scanning) and photon (by volumetric modulated arc therapy) treatments were planned with three isocenters. An 'in silico' ideal background dose was created first to cover the upper-spinal target and to produce a perfect dose gradient along the upper and lower junction regions. Using it as background, the cranial and the lower-spinal beams were planned by inverse optimization to obtain dose coverage of their relevant targets and of the junction volumes. Finally, the upper-spinal beam was inversely planned after removal of the background dose and with the previously optimized beams switched on. In both proton and photon plans, the optimized cranial and the lower-spinal beams produced a perfect linear gradient in the junction regions, complementary to that produced by the optimized upper-spinal beam. The final dose distributions showed a homogeneous coverage of the targets. Our simple technique allowed to obtain high-quality gradients in the junction region. Such technique universally works for photons as well as protons and could be applicable to the TPSs that allow to manage a background dose. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

Inhibition of recombinase polymerase amplification by background DNA: a lateral flow-based method for enriching target DNA.

PubMed

Rohrman, Brittany; Richards-Kortum, Rebecca

2015-02-03

Recombinase polymerase amplification (RPA) may be used to detect a variety of pathogens, often after minimal sample preparation. However, previous work has shown that whole blood inhibits RPA. In this paper, we show that the concentrations of background DNA found in whole blood prevent the amplification of target DNA by RPA. First, using an HIV-1 RPA assay with known concentrations of nonspecific background DNA, we show that RPA tolerates more background DNA when higher HIV-1 target concentrations are present. Then, using three additional assays, we demonstrate that the maximum amount of background DNA that may be tolerated in RPA reactions depends on the DNA sequences used in the assay. We also show that changing the RPA reaction conditions, such as incubation time and primer concentration, has little effect on the ability of RPA to function when high concentrations of background DNA are present. Finally, we develop and characterize a lateral flow-based method for enriching the target DNA concentration relative to the background DNA concentration. This sample processing method enables RPA of 10(4) copies of HIV-1 DNA in a background of 0-14 μg of background DNA. Without lateral flow sample enrichment, the maximum amount of background DNA tolerated is 2 μg when 10(6) copies of HIV-1 DNA are present. This method requires no heating or other external equipment, may be integrated with upstream DNA extraction and purification processes, is compatible with the components of lysed blood, and has the potential to detect HIV-1 DNA in infant whole blood with high proviral loads.

Engineering Ethics Education : Its Necessity, Objectives, Methods, Current State, and Challenges

NASA Astrophysics Data System (ADS)

Fudano, Jun

The importance of engineering ethics education has become widely recognized in the industrialized countries including Japan. This paper examines the background against which engineering ethics education is required, and reviews its objectives, methods, and challenges, as well as its current state. In pointing out important issues associated with the apparent acceptance and quantitative development of ethics education, especially after the establishment of the Japan Accreditation Board for Engineering Education in 1999, the author stresses that the most serious problem is the lack of common understanding on the objectives of engineering ethics education. As a strategy to improve the situation, the so-called “Ethics-across-the-Curriculum” approach is introduced. The author also claims that business/organization ethics which is consistent with engineering ethics should be promoted in Japan.

Methods for Specific Electrode Resistance Measurement during Transcranial Direct Current Stimulation

PubMed Central

Khadka, Niranjan; Rahman, Asif; Sarantos, Chris; Truong, Dennis Q.; Bikson, Marom

2014-01-01

Background Transcranial Direct Current Stimulation (tDCS) is investigated to treat a wide range of neuropsychiatric disorders, for rehabilitation, and for enhancing cognitive performance. The monitoring of electrode resistance before and during tDCS is considered important for tolerability and safety, where an unusually high resistance is indicative of undesired electrode or poor skin contact conditions. Conventional resistance measurement methods do not isolate individual electrode resistance but rather measures overall voltage. Moreover, for HD-tDCS devices, cross talk across electrodes makes concurrent resistance monitoring unreliable. Objective We propose a novel method for monitoring of the individual electrode resistance during tDCS, using a super-position of direct current with a test-signal (low-intensity and low-frequency sinusoids with electrode– specific frequencies) and a single sentinel electrode (not used for DC). Methods To validate this methodology, we developed lumped-parameter models of two and multi-electrode tDCS. Approaches with and without a sentinel electrode were solved and underlying assumptions identified. Assumptions were tested and parameterized in healthy participants using forearm stimulation combining tDCS (2 mA) and sinusoidal test-signals (38 μA and 76 μA peak to peak at 1 Hz, 10 Hz, and 100 Hz) and an in vitro test (where varied electrode failure modes were created). DC and AC component voltages across the electrodes were compared and participants were asked to rate subjective pain. Results A sentinel electrode is required to isolate electrode resistance in a two-electrode tDCS system. For multi-electrode resistance tracking, cross talk was aggravated with electrode proximity and current/resistance mismatches, but could be corrected using proposed approaches. Average voltage and average pain scores were not significantly different across test current intensities and frequencies (two-way repeated measures ANOVA) indicating the

A novel background field removal method for MRI using projection onto dipole fields (PDF).

PubMed

Liu, Tian; Khalidov, Ildar; de Rochefort, Ludovic; Spincemaille, Pascal; Liu, Jing; Tsiouris, A John; Wang, Yi

2011-11-01

For optimal image quality in susceptibility-weighted imaging and accurate quantification of susceptibility, it is necessary to isolate the local field generated by local magnetic sources (such as iron) from the background field that arises from imperfect shimming and variations in magnetic susceptibility of surrounding tissues (including air). Previous background removal techniques have limited effectiveness depending on the accuracy of model assumptions or information input. In this article, we report an observation that the magnetic field for a dipole outside a given region of interest (ROI) is approximately orthogonal to the magnetic field of a dipole inside the ROI. Accordingly, we propose a nonparametric background field removal technique based on projection onto dipole fields (PDF). In this PDF technique, the background field inside an ROI is decomposed into a field originating from dipoles outside the ROI using the projection theorem in Hilbert space. This novel PDF background removal technique was validated on a numerical simulation and a phantom experiment and was applied in human brain imaging, demonstrating substantial improvement in background field removal compared with the commonly used high-pass filtering method. Copyright © 2011 John Wiley & Sons, Ltd.

ViBe: a universal background subtraction algorithm for video sequences.

PubMed

Barnich, Olivier; Van Droogenbroeck, Marc

2011-06-01

This paper presents a technique for motion detection that incorporates several innovative mechanisms. For example, our proposed technique stores, for each pixel, a set of values taken in the past at the same location or in the neighborhood. It then compares this set to the current pixel value in order to determine whether that pixel belongs to the background, and adapts the model by choosing randomly which values to substitute from the background model. This approach differs from those based upon the classical belief that the oldest values should be replaced first. Finally, when the pixel is found to be part of the background, its value is propagated into the background model of a neighboring pixel. We describe our method in full details (including pseudo-code and the parameter values used) and compare it to other background subtraction techniques. Efficiency figures show that our method outperforms recent and proven state-of-the-art methods in terms of both computation speed and detection rate. We also analyze the performance of a downscaled version of our algorithm to the absolute minimum of one comparison and one byte of memory per pixel. It appears that even such a simplified version of our algorithm performs better than mainstream techniques.

Current Background Noise Sources and Levels in the NASA Ames 40- by 80-Foot Wind Tunnel: A Status Report

NASA Technical Reports Server (NTRS)

Allen, Christopher S.; Jaeger, Stephen; Soderman, Paul; Koga, Dennis (Technical Monitor)

1999-01-01

Background noise measurements were made of the acoustic environment in the National Full-Scale Aerodynamics Complex 40- by 80-Foot Wind Tunnel (40x80) at NASA Ames Research Center. The measurements were acquired subsequent to the 40x80 Aeroacoustic Modernization Project, which was undertaken to improve the anechoic characteristics of the 40x80's closed test section as well as reduce the levels of background noise in the facility. The resulting 40x80 anechoic environment was described by Soderman et. al., and the current paper describes the resulting 40x80 background noise, discusses the sources of the noise, and draws comparisons to previous 40x80 background noise levels measurements. At low wind speeds or low frequencies, the 40x80 background noise is dominated by the fan drive system. To obtain the lowest fan drive noise for a given tunnel condition, it is possible in the 40x80 to reduce the fans' rotational speed and adjust the fans' blade pitch, as described by Schmidtz et. al. This idea is not new, but has now been operationally implemented with modifications for increased power at low rotational speeds. At low to mid-frequencies and at higher wind speeds, the dominant noise mechanism was thought to be caused by the surface interface of the previous test section floor acoustic lining. In order to reduce this noise mechanism, the new test section floor lining was designed to resist the pumping of flow in and out of the space between the grating slats required to support heavy equipment. In addition, the lining/flow interface over the entire test section was designed to be smoother and quieter than the previous design. At high wind speeds or high frequencies, the dominant source of background noise in the 40x80 is believed to be caused by the response of the in-flow microphone probes (required by the nature of the closed test section) to the fluctuations in the freestream flow. The resulting background noise levels are also different for probes of various

Raman background photobleaching as a possible method of cancer diagnostics

NASA Astrophysics Data System (ADS)

Brandt, Nikolai N.; Brandt, Nikolai B.; Chikishev, Andrey Y.; Gangardt, Mihail G.; Karyakina, Nina F.

2001-06-01

Kinetics of photobleaching of background in Raman spectra of aqueous solutions of plant toxins ricin and ricin agglutinin, ricin binding subunit, and normal and malignant human blood serum were measured. For the excitation of the spectra cw and pulsed laser radiation were used. The spectra of Raman background change upon laser irradiation. Background intensity is lower for the samples with small molecular weight. The cyclization of amino acid residues in the toxin molecules as well as in human blood serum can be a reason of the Raman background. The model of the background photobleaching is proposed. The differences in photobleaching kinetics in the cases of cw and pulsed laser radiation are discussed. It is shown that Raman background photobleaching can be very informative for cancer diagnostics.

Ultra-Low Background Measurements Of Decayed Aerosol Filters

NASA Astrophysics Data System (ADS)

Miley, H.

2009-04-01

To experimentally evaluate the opportunity to apply ultra-low background measurement methods to samples collected, for instance, by the Comprehensive Test Ban Treaty International Monitoring System (IMS), aerosol samples collected on filter media were measured using HPGe spectrometers of varying low-background technology approaches. In this way, realistic estimates of the impact of low-background methodology can be assessed on the Minimum Detectable Activities obtained in systems such as the IMS. The current measurement requirement of stations in the IMS is 30 microBq per cubic meter of air for 140Ba, or about 106 fissions per daily sample. Importantly, this is for a fresh aerosol filter. Decay varying form 3 days to one week reduce the intrinsic background from radon daughters in the sample. Computational estimates of the improvement factor for these decayed filters for underground-based HPGe in clean shielding materials are orders of magnitude less, even when the decay of the isotopes of interest is included.

Research on infrared ship detection method in sea-sky background

NASA Astrophysics Data System (ADS)

Tang, Da; Sun, Gang; Wang, Ding-he; Niu, Zhao-dong; Chen, Zeng-ping

2013-09-01

An approach to infrared ship detection based on sea-sky-line(SSL) detection, ROI extraction and feature recognition is proposed in this paper. Firstly, considering that far ships are expected to be adjacent to the SSL, SSL is detected to find potential target areas. Radon transform is performed on gradient image to choose candidate SSLs, and detection result is given by fuzzy synthetic evaluation values. Secondly, in view of recognizable condition that there should be enough differences between target and background in infrared image, two gradient masks have been created and improved as practical guidelines in eliminating false alarm. Thirdly, extract ROI near the SSL by using multi-grade segmentation and fusion method after image sharpening, and unsuitable candidates are screened out according to the gradient masks and ROI shape. Finally, we segment the rest of ROIs by two-stage modified OTSU, and calculate target confidence as a standard measuring the facticity of target. Compared with other ship detection methods, proposed method is suitable for bipolar targets, which offers a good practicability and accuracy, and achieves a satisfying detection speed. Detection experiments with 200 thousand frames show that the proposed method is widely applicable, powerful in resistance to interferences and noises with a detection rate of above 95%, which satisfies the engineering needs commendably.

Method of Breast Reconstruction Determines Venous Thromboembolism Risk Better Than Current Prediction Models

PubMed Central

Patel, Niyant V.; Wagner, Douglas S.

2015-01-01

Background: Venous thromboembolism (VTE) risk models including the Davison risk score and the 2005 Caprini risk assessment model have been validated in plastic surgery patients. However, their utility and predictive value in breast reconstruction has not been well described. We sought to determine the utility of current VTE risk models in this population and the VTE rate observed in various methods of breast reconstruction. Methods: A retrospective review of breast reconstructions by a single surgeon was performed. One hundred consecutive transverse rectus abdominis myocutaneous (TRAM) patients, 100 consecutive implant patients, and 100 consecutive latissimus dorsi patients were identified over a 10-year period. Patient demographics and presence of symptomatic VTE were collected. 2005 Caprini risk scores and Davison risk scores were calculated for each patient. Results: The TRAM reconstruction group was found to have a higher VTE rate (6%) than the implant (0%) and latissimus (0%) reconstruction groups (P < 0.01). Mean Davison risk scores and 2005 Caprini scores were similar across all reconstruction groups (P > 0.1). The vast majority of patients were stratified as high risk (87.3%) by the VTE risk models. However, only TRAM reconstruction patients demonstrated significant VTE risk. Conclusions: TRAM reconstruction appears to have a significantly higher risk of VTE than both implant and latissimus reconstruction. Current risk models do not effectively stratify breast reconstruction patients at risk for VTE. The method of breast reconstruction appears to have a significant role in patients’ VTE risk. PMID:26090287

Applied Ecosystem Analysis - Background : EDT the Ecosystem Diagnosis and Treatment Method.

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

Mobrand, Lars E.

1996-05-01

This volume consists of eight separate reports. We present them as background to the Ecosystem Diagnosis and Treatment (EDT) methodology. They are a selection from publications, white papers, and presentations prepared over the past two years. Some of the papers are previously published, others are currently being prepared for publication. In the early to mid 1980`s the concern for failure of both natural and hatchery production of Columbia river salmon populations was widespread. The concept of supplementation was proposed as an alternative solution that would integrate artificial propagation with natural production. In response to the growing expectations placed upon themore » supplementation tool, a project called Regional Assessment of Supplementation Project (RASP) was initiated in 1990. The charge of RASP was to define supplementation and to develop guidelines for when, where and how it would be the appropriate solution to salmon enhancement in the Columbia basin. The RASP developed a definition of supplementation and a set of guidelines for planning salmon enhancement efforts which required consideration of all factors affecting salmon populations, including environmental, genetic, and ecological variables. The results of RASP led to a conclusion that salmon issues needed to be addressed in a manner that was consistent with an ecosystem approach. If the limitations and potentials of supplementation or any other management tool were to be fully understood it would have to be within the context of a broadly integrated approach - thus the Ecosystem Diagnosis and Treatment (EDT) method was born.« less

The Cosmic Infrared Background Experiment (CIBER): A Sounding Rocket Payload to Study the near Infrared Extragalactic Background Light

NASA Astrophysics Data System (ADS)

Zemcov, M.; Arai, T.; Battle, J.; Bock, J.; Cooray, A.; Hristov, V.; Keating, B.; Kim, M. G.; Lee, D. H.; Levenson, L. R.; Mason, P.; Matsumoto, T.; Matsuura, S.; Nam, U. W.; Renbarger, T.; Sullivan, I.; Suzuki, K.; Tsumura, K.; Wada, T.

2013-08-01

The Cosmic Infrared Background Experiment (CIBER) is a suite of four instruments designed to study the near infrared (IR) background light from above the Earth's atmosphere. The instrument package comprises two imaging telescopes designed to characterize spatial anisotropy in the extragalactic IR background caused by cosmological structure during the epoch of reionization, a low resolution spectrometer to measure the absolute spectrum of the extragalactic IR background, and a narrow band spectrometer optimized to measure the absolute brightness of the zodiacal light foreground. In this paper we describe the design and characterization of the CIBER payload. The detailed mechanical, cryogenic, and electrical design of the system are presented, including all system components common to the four instruments. We present the methods and equipment used to characterize the instruments before and after flight, and give a detailed description of CIBER's flight profile and configurations. CIBER is designed to be recoverable and has flown four times, with modifications to the payload having been informed by analysis of the first flight data. All four instruments performed to specifications during the subsequent flights, and the scientific data from these flights are currently being analyzed.

THE COSMIC INFRARED BACKGROUND EXPERIMENT (CIBER): A SOUNDING ROCKET PAYLOAD TO STUDY THE NEAR INFRARED EXTRAGALACTIC BACKGROUND LIGHT

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

Zemcov, M.; Bock, J.; Hristov, V.

2013-08-15

The Cosmic Infrared Background Experiment (CIBER) is a suite of four instruments designed to study the near infrared (IR) background light from above the Earth's atmosphere. The instrument package comprises two imaging telescopes designed to characterize spatial anisotropy in the extragalactic IR background caused by cosmological structure during the epoch of reionization, a low resolution spectrometer to measure the absolute spectrum of the extragalactic IR background, and a narrow band spectrometer optimized to measure the absolute brightness of the zodiacal light foreground. In this paper we describe the design and characterization of the CIBER payload. The detailed mechanical, cryogenic, andmore » electrical design of the system are presented, including all system components common to the four instruments. We present the methods and equipment used to characterize the instruments before and after flight, and give a detailed description of CIBER's flight profile and configurations. CIBER is designed to be recoverable and has flown four times, with modifications to the payload having been informed by analysis of the first flight data. All four instruments performed to specifications during the subsequent flights, and the scientific data from these flights are currently being analyzed.« less

A novel infrared small moving target detection method based on tracking interest points under complicated background

NASA Astrophysics Data System (ADS)

Dong, Xiabin; Huang, Xinsheng; Zheng, Yongbin; Bai, Shengjian; Xu, Wanying

2014-07-01

Infrared moving target detection is an important part of infrared technology. We introduce a novel infrared small moving target detection method based on tracking interest points under complicated background. Firstly, Difference of Gaussians (DOG) filters are used to detect a group of interest points (including the moving targets). Secondly, a sort of small targets tracking method inspired by Human Visual System (HVS) is used to track these interest points for several frames, and then the correlations between interest points in the first frame and the last frame are obtained. Last, a new clustering method named as R-means is proposed to divide these interest points into two groups according to the correlations, one is target points and another is background points. In experimental results, the target-to-clutter ratio (TCR) and the receiver operating characteristics (ROC) curves are computed experimentally to compare the performances of the proposed method and other five sophisticated methods. From the results, the proposed method shows a better discrimination of targets and clutters and has a lower false alarm rate than the existing moving target detection methods.

CUORE and Background Reduction Case Studies for CUPID

NASA Astrophysics Data System (ADS)

Sakai, Michinari; Gozlukluoglu, Nihal; Huang, Huan; Cuore Collaboration

2017-09-01

CUORE (Cryogenic Underground Observatory for Rare Events) is a bolometric experiment at cryogenic temperatures currently in operation to search for neutrinoless double beta decay. Successful detection of this extremely rare process requires stringent control of radioactive backgrounds of the experiment as well as the detector itself. Great care was taken in CUORE to select the materials and various parts that comprise the current detector. However next-generation neutrinoless double beta decay experiments face a challenge to further reduce backgrounds in order to probe more deeply into the effective Majorana neutrino mass phase space. In this presentation we will review the sensitivity and background budget for the currently running experiment CUORE, as well as the target sensitivity and background goals for the next generation experiment CUPID that will cover the inverted neutrino mass hierarchy. We will explore simulation based R&D case studies for background reduction and lay out achievable background reduction levels using possible materials and feasible geometries in the context of CUPID. National Science Foundation.

Direct current uninterruptible power supply method and system

DOEpatents

Sinha, Gautam

2003-12-02

A method and system are described for providing a direct current (DC) uninterruptible power supply with the method including, for example: continuously supplying fuel to a turbine; converting mechanical power from the turbine into alternating current (AC) electrical power; converting the AC electrical power to DC power within a predetermined voltage level range; supplying the DC power to a load; and maintaining a DC load voltage within the predetermined voltage level range by adjusting the amount of fuel supplied to the turbine.

A New Moving Object Detection Method Based on Frame-difference and Background Subtraction

NASA Astrophysics Data System (ADS)

Guo, Jiajia; Wang, Junping; Bai, Ruixue; Zhang, Yao; Li, Yong

2017-09-01

Although many methods of moving object detection have been proposed, moving object extraction is still the core in video surveillance. However, with the complex scene in real world, false detection, missed detection and deficiencies resulting from cavities inside the body still exist. In order to solve the problem of incomplete detection for moving objects, a new moving object detection method combined an improved frame-difference and Gaussian mixture background subtraction is proposed in this paper. To make the moving object detection more complete and accurate, the image repair and morphological processing techniques which are spatial compensations are applied in the proposed method. Experimental results show that our method can effectively eliminate ghosts and noise and fill the cavities of the moving object. Compared to other four moving object detection methods which are GMM, VIBE, frame-difference and a literature's method, the proposed method improve the efficiency and accuracy of the detection.

Method and apparatus for current-output peak detection

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

De Geronimo, Gianluigi

2017-01-24

A method and apparatus for a current-output peak detector. A current-output peak detector circuit is disclosed and works in two phases. The peak detector circuit includes switches to switch the peak detector circuit from the first phase to the second phase upon detection of the peak voltage of an input voltage signal. The peak detector generates a current output with a high degree of accuracy in the second phase.

The current matrix elements from HAL QCD method

NASA Astrophysics Data System (ADS)

Watanabe, Kai; Ishii, Noriyoshi

2018-03-01

HAL QCD method is a method to construct a potential (HAL QCD potential) that reproduces the NN scattering phase shift faithful to the QCD. The HAL QCD potential is obtained from QCD by eliminating the degrees of freedom of quarks and gluons and leaving only two particular hadrons. Therefor, in the effective quantum mechanics of two nucleons defined by HAL QCD potential, the conserved current consists not only of the nucleon current but also an extra current originating from the potential (two-body current). Though the form of the two-body current is closely related to the potential, it is not straight forward to extract the former from the latter. In this work, we derive the the current matrix element formula in the quantum mechanics defined by the HAL QCD potential. As a first step, we focus on the non-relativistic case. To give an explicit example, we consider a second quantized non-relativistic two-channel coupling model which we refer to as the original model. From the original model, the HAL QCD potential for the open channel is constructed by eliminating the closed channel in the elastic two-particle scattering region. The current matrix element formula is derived by demanding the effective quantum mechanics defined by the HAL QCD potential to respond to the external field in the same way as the original two-channel coupling model.

Recursive least squares background prediction of univariate syndromic surveillance data

PubMed Central

2009-01-01

Background Surveillance of univariate syndromic data as a means of potential indicator of developing public health conditions has been used extensively. This paper aims to improve the performance of detecting outbreaks by using a background forecasting algorithm based on the adaptive recursive least squares method combined with a novel treatment of the Day of the Week effect. Methods Previous work by the first author has suggested that univariate recursive least squares analysis of syndromic data can be used to characterize the background upon which a prediction and detection component of a biosurvellance system may be built. An adaptive implementation is used to deal with data non-stationarity. In this paper we develop and implement the RLS method for background estimation of univariate data. The distinctly dissimilar distribution of data for different days of the week, however, can affect filter implementations adversely, and so a novel procedure based on linear transformations of the sorted values of the daily counts is introduced. Seven-days ahead daily predicted counts are used as background estimates. A signal injection procedure is used to examine the integrated algorithm's ability to detect synthetic anomalies in real syndromic time series. We compare the method to a baseline CDC forecasting algorithm known as the W2 method. Results We present detection results in the form of Receiver Operating Characteristic curve values for four different injected signal to noise ratios using 16 sets of syndromic data. We find improvements in the false alarm probabilities when compared to the baseline W2 background forecasts. Conclusion The current paper introduces a prediction approach for city-level biosurveillance data streams such as time series of outpatient clinic visits and sales of over-the-counter remedies. This approach uses RLS filters modified by a correction for the weekly patterns often seen in these data series, and a threshold detection algorithm from the

Constant-current control method of multi-function electromagnetic transmitter.

PubMed

Xue, Kaichang; Zhou, Fengdao; Wang, Shuang; Lin, Jun

2015-02-01

Based on the requirements of controlled source audio-frequency magnetotelluric, DC resistivity, and induced polarization, a constant-current control method is proposed. Using the required current waveforms in prospecting as a standard, the causes of current waveform distortion and current waveform distortion's effects on prospecting are analyzed. A cascaded topology is adopted to achieve 40 kW constant-current transmitter. The responsive speed and precision are analyzed. According to the power circuit of the transmitting system, the circuit structure of the pulse width modulation (PWM) constant-current controller is designed. After establishing the power circuit model of the transmitting system and the PWM constant-current controller model, analyzing the influence of ripple current, and designing an open-loop transfer function according to the amplitude-frequency characteristic curves, the parameters of the PWM constant-current controller are determined. The open-loop transfer function indicates that the loop gain is no less than 28 dB below 160 Hz, which assures the responsive speed of the transmitting system; the phase margin is 45°, which assures the stabilization of the transmitting system. Experimental results verify that the proposed constant-current control method can keep the control error below 4% and can effectively suppress load change caused by the capacitance of earth load.

Constant-current control method of multi-function electromagnetic transmitter

NASA Astrophysics Data System (ADS)

Xue, Kaichang; Zhou, Fengdao; Wang, Shuang; Lin, Jun

2015-02-01

Based on the requirements of controlled source audio-frequency magnetotelluric, DC resistivity, and induced polarization, a constant-current control method is proposed. Using the required current waveforms in prospecting as a standard, the causes of current waveform distortion and current waveform distortion's effects on prospecting are analyzed. A cascaded topology is adopted to achieve 40 kW constant-current transmitter. The responsive speed and precision are analyzed. According to the power circuit of the transmitting system, the circuit structure of the pulse width modulation (PWM) constant-current controller is designed. After establishing the power circuit model of the transmitting system and the PWM constant-current controller model, analyzing the influence of ripple current, and designing an open-loop transfer function according to the amplitude-frequency characteristic curves, the parameters of the PWM constant-current controller are determined. The open-loop transfer function indicates that the loop gain is no less than 28 dB below 160 Hz, which assures the responsive speed of the transmitting system; the phase margin is 45°, which assures the stabilization of the transmitting system. Experimental results verify that the proposed constant-current control method can keep the control error below 4% and can effectively suppress load change caused by the capacitance of earth load.

The influence of immigrant background on the choice of sedation method in paediatric dentistry.

PubMed

Dahlander, Andreas; Jansson, Leif; Carlstedt, Kerstin; Grindefjord, Margaret

2015-01-01

The effects of immigration on the demographics of the Swedish population have changed the situation for many dental care providers, placing increased demand on cultural competence. The aim of this investigation was to study the choice of sedation method among children with immigrant background, referred to paediatric dentistry specialists, because of behaviour management problems or dental fear in combination with treatment needs. The material consisted of dental records from children referred to two clinics for paediatric dentistry: 117 records from children with an immigrant background and 106 from children with a non-immigrant background. Information about choice of sedation method (conventional treatment, conscious sedation with midazolam, nitrous oxide, or general anaesthesia) and dental status was collected from the records. The number of missed appointments (defaults) was also registered. Binary logistic regression analyses were used to calculate the influence of potential predictors on choice of sedation method. The mean age of the patients in the immigrant group was 4.9 yrs, making them significantly younger than the patients in the non-immigrant group (mean 5.7 yrs). In the immigrant group, 26% of the patients defaulted from treatments, while the corresponding frequency was significantly lower for the reference group (7%). The numbers of primary teeth with caries and permanent teeth with caries were positively and significantly correlated with the choice of treatment under general anaesthesia. Conscious sedation was used significantly more often in younger children and in the non-immigrant group, while nitrous oxide was preferred in the older children. In conclusion, conscious sedation was more frequently used in the non-immigrant group. The choice of sedation was influenced by caries frequency and the age of the child.

SWCD: a sliding window and self-regulated learning-based background updating method for change detection in videos

NASA Astrophysics Data System (ADS)

Işık, Şahin; Özkan, Kemal; Günal, Serkan; Gerek, Ömer Nezih

2018-03-01

Change detection with background subtraction process remains to be an unresolved issue and attracts research interest due to challenges encountered on static and dynamic scenes. The key challenge is about how to update dynamically changing backgrounds from frames with an adaptive and self-regulated feedback mechanism. In order to achieve this, we present an effective change detection algorithm for pixelwise changes. A sliding window approach combined with dynamic control of update parameters is introduced for updating background frames, which we called sliding window-based change detection. Comprehensive experiments on related test videos show that the integrated algorithm yields good objective and subjective performance by overcoming illumination variations, camera jitters, and intermittent object motions. It is argued that the obtained method makes a fair alternative in most types of foreground extraction scenarios; unlike case-specific methods, which normally fail for their nonconsidered scenarios.

Pediatric stroke and transcranial direct current stimulation: methods for rational individualized dose optimization

PubMed Central

Gillick, Bernadette T.; Kirton, Adam; Carmel, Jason B.; Minhas, Preet; Bikson, Marom

2014-01-01

Background: Transcranial direct current stimulation (tDCS) has been investigated mainly in adults and doses may not be appropriate in pediatric applications. In perinatal stroke where potential applications are promising, rational adaptation of dosage for children remains under investigation. Objective: Construct child-specific tDCS dosing parameters through case study within a perinatal stroke tDCS safety and feasibility trial. Methods: 10-year-old subject with a diagnosis of presumed perinatal ischemic stroke and hemiparesis was identified. T1 magnetic resonance imaging (MRI) scans used to derive computerized model for current flow and electrode positions. Workflow using modeling results and consideration of dosage in previous clinical trials was incorporated. Prior ad hoc adult montages vs. de novo optimized montages provided distinct risk benefit analysis. Approximating adult dose required consideration of changes in both peak brain current flow and distribution which further tradeoff between maximizing efficacy and adding safety factors. Electrode size, position, current intensity, compliance voltage, and duration were controlled independently in this process. Results: Brain electric fields modeled and compared to values previously predicted models (Datta et al., 2011; Minhas et al., 2012). Approximating conservative brain current flow patterns and intensities used in previous adult trials for comparable indications, the optimal current intensity established was 0.7 mA for 10 min with a tDCS C3/C4 montage. Specifically 0.7 mA produced comparable peak brain current intensity of an average adult receiving 1.0 mA. Electrode size of 5 × 7 cm2 with 1.0 mA and low-voltage tDCS was employed to maximize tolerability. Safety and feasibility confirmed with subject tolerating the session well and no serious adverse events. Conclusion: Rational approaches to dose customization, with steps informed by computational modeling, may improve guidance for pediatric stroke t

Eddy Current System and Method for Crack Detection

NASA Technical Reports Server (NTRS)

Wincheski, Russell A. (Inventor); Simpson, John W. (Inventor)

2012-01-01

An eddy current system and method enables detection of sub-surface damage in a cylindrical object. The invention incorporates a dual frequency, orthogonally wound eddy current probe mounted on a stepper motor-controlled scanning system. The system is designed to inspect for outer surface damage from the interior of the cylindrical object.

Evaluation of background radiation dose contributions in the United Arab Emirates.

PubMed

Goddard, Braden; Bosc, Emmanuel; Al Hasani, Sarra; Lloyd, Cody

2018-09-01

The natural background radiation consists of three main components; cosmic, terrestrial, and skyshine. Although there are currently methods available to measure the total dose rate from background radiation, no established methods exist that allow for the measurement of each component the background radiation. This analysis consists of a unique methodology in which the dose rate contribution from each component of the natural background radiation is measured and calculated. This project evaluates the natural background dose rate in the Abu Dhabi City region from all three of these components using the developed methodology. Evaluating and understanding the different components of background radiation provides a baseline allowing for the detection, and possibly attribution, of elevated radiation levels. Measurements using a high-pressure ion chamber with different shielding configurations and two offshore measurements provided dose rate information that were attributed to the different components of the background radiation. Additional spectral information was obtained using an HPGe detector to verify and quantify the presence of terrestrial radionuclides. By evaluating the dose rates of the different shielding configurations the comic, terrestrial, and skyshine contribution in the Abu Dhabi City region were determined to be 33.0 ± 1.7, 15.7 ± 2.5, and 2.4 ± 2.1 nSv/h, respectively. Copyright © 2018. Published by Elsevier Ltd.

Current trends in feminist nursing research.

PubMed

Im, Eun-Ok

2010-01-01

Despite an increasing number of feminist studies in nursing, few reviews on current trends in feminist nursing research have been published. This article aims to explore the current trends in feminist nursing research and provide recommendations for future feminist studies in nursing. In multiple database searches, 207 articles were retrieved. These were reviewed based on 5 criteria: (1) epistemological background, (2) research questions, (3) research participants, (4) research methods, and (5) implications for changes. The review indicated that feminist nurse researchers with diverse epistemological backgrounds adopted new research methods to ask new questions; expanded their focus to include differences in ethnicity, class, sexual preference, and disability; and incorporated these diversities among women in a global context in their research. Based on these findings, recommendations for future feminist research in nursing are outlined. Copyright 2010 Mosby, Inc. All rights reserved.

A Survey of Hospice Volunteer Coordinators: Training Methods and Objectives of Current Hospice Volunteer Training Programs.

PubMed

Brock, Cara M; Herndon, Christopher M

2017-06-01

Currently more than 5800 hospice organizations operate in the United States. 1 Hospice organizations are required by the Centers for Medicare and Medicaid Services (CMS) to use volunteers for services provided to patients. 2 Although CMS regulates the amount of hours hospice volunteers should provide, there are currently no national requirements for objectives of training. 3 The purpose of this study was to gather information from a sample of hospices regarding volunteer coordinator background, current training for volunteers, importance of training objectives, and any comments regarding additional objectives. Representative state hospice organizations were contacted by e-mail requesting their participation and distribution of the survey throughout their member hospices. The survey asked demographical questions, along with ratings of training components based on perceived level of importance and time spent on each objective. A total of 90 surveys were received, and the response rate was undeterminable. Results showed the majority of hospices were nonprofit, had less than 100 currently trained volunteers, and maintained an average daily patient census of less than 50. Questions regarding training programs indicated that most use live lecture methods of approximately 19 hours or less in duration. Overall, responding hospice organizations agreed that all objectives surveyed were important in training volunteers. The small number of respondents to this survey makes generalization nationwide difficult, however it is a strong starting point for the development of further surveys on hospice volunteer training and achieving a standardized set of training objectives and delivery methods.

Method and apparatus for measuring low currents in capacitance devices

DOEpatents

Kopp, M.K.; Manning, F.W.; Guerrant, G.C.

1986-06-04

A method and apparatus for measuring subnanoampere currents in capacitance devices is reported. The method is based on a comparison of the voltages developed across the capacitance device with that of a reference capacitor in which the current is adjusted by means of a variable current source to produce a stable voltage difference. The current varying means of the variable current source is calibrated to provide a read out of the measured current. Current gain may be provided by using a reference capacitor which is larger than the device capacitance with a corresponding increase in current supplied through the reference capacitor. The gain is then the ratio of the reference capacitance to the device capacitance. In one illustrated embodiment, the invention makes possible a new type of ionizing radiation dose-rate monitor where dose-rate is measured by discharging a reference capacitor with a variable current source at the same rate that radiation is discharging an ionization chamber. The invention eliminates high-megohm resistors and low current ammeters used in low-current measuring instruments.

[The validation of the effect of correcting spectral background changes based on floating reference method by simulation].

PubMed

Wang, Zhu-lou; Zhang, Wan-jie; Li, Chen-xi; Chen, Wen-liang; Xu, Ke-xin

2015-02-01

There are some challenges in near-infrared non-invasive blood glucose measurement, such as the low signal to noise ratio of instrument, the unstable measurement conditions, the unpredictable and irregular changes of the measured object, and etc. Therefore, it is difficult to extract the information of blood glucose concentrations from the complicated signals accurately. Reference measurement method is usually considered to be used to eliminate the effect of background changes. But there is no reference substance which changes synchronously with the anylate. After many years of research, our research group has proposed the floating reference method, which is succeeded in eliminating the spectral effects induced by the instrument drifts and the measured object's background variations. But our studies indicate that the reference-point will changes following the changing of measurement location and wavelength. Therefore, the effects of floating reference method should be verified comprehensively. In this paper, keeping things simple, the Monte Carlo simulation employing Intralipid solution with the concentrations of 5% and 10% is performed to verify the effect of floating reference method used into eliminating the consequences of the light source drift. And the light source drift is introduced through varying the incident photon number. The effectiveness of the floating reference method with corresponding reference-points at different wavelengths in eliminating the variations of the light source drift is estimated. The comparison of the prediction abilities of the calibration models with and without using this method shows that the RMSEPs of the method are decreased by about 98.57% (5%Intralipid)and 99.36% (10% Intralipid)for different Intralipid. The results indicate that the floating reference method has obvious effect in eliminating the background changes.

Control of Phasic Firing by a Background Leak Current in Avian Forebrain Auditory Neurons

PubMed Central

Dagostin, André A.; Lovell, Peter V.; Hilscher, Markus M.; Mello, Claudio V.; Leão, Ricardo M.

2015-01-01

Central neurons express a variety of neuronal types and ion channels that promote firing heterogeneity among their distinct neuronal populations. Action potential (AP) phasic firing, produced by low-threshold voltage-activated potassium currents (VAKCs), is commonly observed in mammalian brainstem neurons involved in the processing of temporal properties of the acoustic information. The avian caudomedial nidopallium (NCM) is an auditory area analogous to portions of the mammalian auditory cortex that is involved in the perceptual discrimination and memorization of birdsong and shows complex responses to auditory stimuli We performed in vitro whole-cell patch-clamp recordings in brain slices from adult zebra finches (Taeniopygia guttata) and observed that half of NCM neurons fire APs phasically in response to membrane depolarizations, while the rest fire transiently or tonically. Phasic neurons fired APs faster and with more temporal precision than tonic and transient neurons. These neurons had similar membrane resting potentials, but phasic neurons had lower membrane input resistance and time constant. Surprisingly phasic neurons did not express low-threshold VAKCs, which curtailed firing in phasic mammalian brainstem neurons, having similar VAKCs to other NCM neurons. The phasic firing was determined not by VAKCs, but by the potassium background leak conductances, which was more prominently expressed in phasic neurons, a result corroborated by pharmacological, dynamic-clamp, and modeling experiments. These results reveal a new role for leak currents in generating firing diversity in central neurons. PMID:26696830

Comparative study of the effectiveness and limitations of current methods for detecting sequence coevolution.

PubMed

Mao, Wenzhi; Kaya, Cihan; Dutta, Anindita; Horovitz, Amnon; Bahar, Ivet

2015-06-15

With rapid accumulation of sequence data on several species, extracting rational and systematic information from multiple sequence alignments (MSAs) is becoming increasingly important. Currently, there is a plethora of computational methods for investigating coupled evolutionary changes in pairs of positions along the amino acid sequence, and making inferences on structure and function. Yet, the significance of coevolution signals remains to be established. Also, a large number of false positives (FPs) arise from insufficient MSA size, phylogenetic background and indirect couplings. Here, a set of 16 pairs of non-interacting proteins is thoroughly examined to assess the effectiveness and limitations of different methods. The analysis shows that recent computationally expensive methods designed to remove biases from indirect couplings outperform others in detecting tertiary structural contacts as well as eliminating intermolecular FPs; whereas traditional methods such as mutual information benefit from refinements such as shuffling, while being highly efficient. Computations repeated with 2,330 pairs of protein families from the Negatome database corroborated these results. Finally, using a training dataset of 162 families of proteins, we propose a combined method that outperforms existing individual methods. Overall, the study provides simple guidelines towards the choice of suitable methods and strategies based on available MSA size and computing resources. Software is freely available through the Evol component of ProDy API. © The Author 2015. Published by Oxford University Press.

Method and apparatus for reducing the harmonic currents in alternating-current distribution networks

DOEpatents

Beverly, Leon H.; Hance, Richard D.; Kristalinski, Alexandr L.; Visser, Age T.

1996-01-01

An improved apparatus and method reduce the harmonic content of AC line and neutral line currents in polyphase AC source distribution networks. The apparatus and method employ a polyphase Zig-Zag transformer connected between the AC source distribution network and a load. The apparatus and method also employs a mechanism for increasing the source neutral impedance of the AC source distribution network. This mechanism can consist of a choke installed in the neutral line between the AC source and the Zig-Zag transformer.

External nasal dilators: definition, background, and current uses

PubMed Central

Dinardi, Ricardo Reis; de Andrade, Cláudia Ribeiro; Ibiapina, Cássio da Cunha

2014-01-01

Our goal was to revise the literature about external nasal dilators (ENDs) as to their definition, history, and current uses. We reviewed journals in the PubMed and MEDLINE databases. The current uses hereby presented and discussed are physical exercise, nasal congestion and sleep, snoring, pregnancy, cancer, and healthy individuals. Numerous studies have shown that ENDs increase the cross-sectional area of the nasal valve, reducing nasal resistance and transnasal inspiratory pressure and stabilizing the lateral nasal vestibule, avoiding its collapse during final inspiration. These effects also facilitate breathing and are beneficial to patients with nasal obstruction. Furthermore, END use is simple, noninvasive, painless, affordable, and bears minimum risk to the user. Most studies have limited sample size and are mainly focused on physical exercise. In conclusion, ENDs seem useful, so further studies involving potential effects on the performance of physical tests and improvements in sleep quality are necessary, especially in children and teenagers. PMID:25419156

Method for measuring and controlling beam current in ion beam processing

DOEpatents

Kearney, Patrick A.; Burkhart, Scott C.

2003-04-29

A method for producing film thickness control of ion beam sputter deposition films. Great improvements in film thickness control is accomplished by keeping the total current supplied to both the beam and suppressor grids of a radio frequency (RF) in beam source constant, rather than just the current supplied to the beam grid. By controlling both currents, using this method, deposition rates are more stable, and this allows the deposition of layers with extremely well controlled thicknesses to about 0.1%. The method is carried out by calculating deposition rates based on the total of the suppressor and beam currents and maintaining the total current constant by adjusting RF power which gives more consistent values.

Method and apparatus for reducing the harmonic currents in alternating-current distribution networks

DOEpatents

Beverly, L.H.; Hance, R.D.; Kristalinski, A.L.; Visser, A.T.

1996-11-19

An improved apparatus and method reduce the harmonic content of AC line and neutral line currents in polyphase AC source distribution networks. The apparatus and method employ a polyphase Zig-Zag transformer connected between the AC source distribution network and a load. The apparatus and method also employs a mechanism for increasing the source neutral impedance of the AC source distribution network. This mechanism can consist of a choke installed in the neutral line between the AC source and the Zig-Zag transformer. 23 figs.

Enumerating viruses by using fluorescence and the nature of the nonviral background fraction.

PubMed

Pollard, Peter C

2012-09-01

Bulk fluorescence measurements could be a faster and cheaper way of enumerating viruses than epifluorescence microscopy, flow cytometry, or transmission electron microscopy (TEM). However, since viruses are not imaged, the background fluorescence compromises the signal, and we know little about its nature. In this paper the size ranges of nucleotides that fluoresce in the presence of SYBR gold were determined for wastewater and a range of freshwater samples using a differential filtration method. Fluorescence excitation-emission matrices (FEEMs) showed that >70% of the SYBR fluorescence was in the <10-nm size fraction (background) and was not associated with intact viruses. This was confirmed using TEM. The use of FEEMs to develop a fluorescence-based method for counting viruses is an approach that is fundamentally different from the epifluorescence microscopy technique used for enumerating viruses. This high fluorescence background is currently overlooked, yet it has had a most pervasive influence on the development of a simple fluorescence-based method for quantifying viral abundance in water.

Detection prospects of the cosmic neutrino background

NASA Astrophysics Data System (ADS)

Li, Yu-Feng

2015-04-01

The existence of the cosmic neutrino background (CνB) is a fundamental prediction of the standard Big Bang cosmology. Although current cosmological probes provide indirect observational evidence, the direct detection of the CνB in a laboratory experiment is a great challenge to the present experimental techniques. We discuss the future prospects for the direct detection of the CνB, with the emphasis on the method of captures on beta-decaying nuclei and the PTOLEMY project. Other possibilities using the electron-capture (EC) decaying nuclei, the annihilation of extremely high-energy cosmic neutrinos (EHECνs) at the Z-resonance, and the atomic de-excitation method are also discussed in this review (talk given at the International Conference on Massive Neutrinos, Singapore, 9-13 February 2015).

Recursive least squares background prediction of univariate syndromic surveillance data.

PubMed

Najmi, Amir-Homayoon; Burkom, Howard

2009-01-16

Surveillance of univariate syndromic data as a means of potential indicator of developing public health conditions has been used extensively. This paper aims to improve the performance of detecting outbreaks by using a background forecasting algorithm based on the adaptive recursive least squares method combined with a novel treatment of the Day of the Week effect. Previous work by the first author has suggested that univariate recursive least squares analysis of syndromic data can be used to characterize the background upon which a prediction and detection component of a biosurvellance system may be built. An adaptive implementation is used to deal with data non-stationarity. In this paper we develop and implement the RLS method for background estimation of univariate data. The distinctly dissimilar distribution of data for different days of the week, however, can affect filter implementations adversely, and so a novel procedure based on linear transformations of the sorted values of the daily counts is introduced. Seven-days ahead daily predicted counts are used as background estimates. A signal injection procedure is used to examine the integrated algorithm's ability to detect synthetic anomalies in real syndromic time series. We compare the method to a baseline CDC forecasting algorithm known as the W2 method. We present detection results in the form of Receiver Operating Characteristic curve values for four different injected signal to noise ratios using 16 sets of syndromic data. We find improvements in the false alarm probabilities when compared to the baseline W2 background forecasts. The current paper introduces a prediction approach for city-level biosurveillance data streams such as time series of outpatient clinic visits and sales of over-the-counter remedies. This approach uses RLS filters modified by a correction for the weekly patterns often seen in these data series, and a threshold detection algorithm from the residuals of the RLS forecasts. We

Motor monitoring method and apparatus using high frequency current components

DOEpatents

Casada, D.A.

1996-05-21

A motor current analysis method and apparatus for monitoring electrical-motor-driven devices are disclosed. The method and apparatus utilize high frequency portions of the motor current spectra to evaluate the condition of the electric motor and the device driven by the electric motor. The motor current signal produced as a result of an electric motor is monitored and the low frequency components of the signal are removed by a high-pass filter. The signal is then analyzed to determine the condition of the electrical motor and the driven device. 16 figs.

Motor monitoring method and apparatus using high frequency current components

DOEpatents

Casada, Donald A.

1996-01-01

A motor current analysis method and apparatus for monitoring electrical-motor-driven devices. The method and apparatus utilize high frequency portions of the motor current spectra to evaluate the condition of the electric motor and the device driven by the electric motor. The motor current signal produced as a result of an electric motor is monitored and the low frequency components of the signal are removed by a high-pass filter. The signal is then analyzed to determine the condition of the electrical motor and the driven device.

Spectral characterization of natural backgrounds

NASA Astrophysics Data System (ADS)

Winkelmann, Max

2017-10-01

As the distribution and use of hyperspectral sensors is constantly increasing, the exploitation of spectral features is a threat for camouflaged objects. To improve camouflage materials at first the spectral behavior of backgrounds has to be known to adjust and optimize the spectral reflectance of camouflage materials. In an international effort, the NATO CSO working group SCI-295 "Development of Methods for Measurements and Evaluation of Natural Background EO Signatures" is developing a method how this characterization of backgrounds has to be done. It is obvious that the spectral characterization of a background will be quite an effort. To compare and exchange data internationally the measurements will have to be done in a similar way. To test and further improve this method an international field trial has been performed in Storkow, Germany. In the following we present first impressions and lessons learned from this field campaign and describe the data that has been measured.

A new method for detecting small and dim targets in starry background

NASA Astrophysics Data System (ADS)

Yao, Rui; Zhang, Yanning; Jiang, Lei

2011-08-01

Small visible optical space targets detection is one of the key issues in the research of long-range early warning and space debris surveillance. The SNR(Signal to Noise Ratio) of the target is very low because of the self influence of image device. Random noise and background movement also increase the difficulty of target detection. In order to detect small visible optical space targets effectively and rapidly, we bring up a novel detecting method based on statistic theory. Firstly, we get a reasonable statistical model of visible optical space image. Secondly, we extract SIFT(Scale-Invariant Feature Transform) feature of the image frames, and calculate the transform relationship, then use the transform relationship to compensate whole visual field's movement. Thirdly, the influence of star was wiped off by using interframe difference method. We find segmentation threshold to differentiate candidate targets and noise by using OTSU method. Finally, we calculate statistical quantity to judge whether there is the target for every pixel position in the image. Theory analysis shows the relationship of false alarm probability and detection probability at different SNR. The experiment result shows that this method could detect target efficiently, even the target passing through stars.

Motor current signature analysis method for diagnosing motor operated devices

DOEpatents

Haynes, Howard D.; Eissenberg, David M.

1990-01-01

A motor current noise signature analysis method and apparatus for remotely monitoring the operating characteristics of an electric motor-operated device such as a motor-operated valve. Frequency domain signal analysis techniques are applied to a conditioned motor current signal to distinctly identify various operating parameters of the motor driven device from the motor current signature. The signature may be recorded and compared with subsequent signatures to detect operating abnormalities and degradation of the device. This diagnostic method does not require special equipment to be installed on the motor-operated device, and the current sensing may be performed at remote control locations, e.g., where the motor-operated devices are used in accessible or hostile environments.

Federal Child Care Policy. Current and Proposed. Family Impact Seminar (Washington, D.C., April 28, 1989). Meeting Highlights and Background Briefing Report.

ERIC Educational Resources Information Center

Ooms, Theodora; Herendeen, Lisa

The purpose of this policy seminar, one of a series of family impact seminars, was to consider current and proposed policies of the federal government that concern child care. This document provides highlights of presentations by the seminar panelists and a background briefing report prepared before the meeting. The highlights section summarizes:…

A method to characterise site, urban and regional ambient background radiation.

PubMed

Passmore, C; Kirr, M

2011-03-01

Control dosemeters are routinely provided to customers to monitor the background radiation so that it can be subtracted from the gross response of the dosemeter to arrive at the occupational dose. Landauer, the largest dosimetry processor in the world with subsidiaries in Australia, Brazil, China, France, Japan, Mexico and the UK, has clients in approximately 130 countries. The Glenwood facility processes over 1.1 million controls per year. This network of clients around the world provides a unique ability to monitor the world's ambient background radiation. Control data can be mined to provide useful historical information regarding ambient background rates and provide a historical baseline for geographical areas. Historical baseline can be used to provide site or region-specific background subtraction values, document the variation in ambient background radiation around a client's site or provide a baseline for measuring the efficiency of clean-up efforts in urban areas after a dirty bomb detonation.

Teaching About Women in Hispanic Literature: Current Methods and Materials.

ERIC Educational Resources Information Center

Maier, Carol

Awareness of a new and altered method of teaching literature, similar to that described by Adrienne Rich, grew from the experience of teaching a small introductory course in twentieth century Hispanic women writers to students with diverse language, cultural, and economic backgrounds. Although about half the students were native Spanish speakers,…

The isotropic radio background revisited

NASA Astrophysics Data System (ADS)

Fornengo, Nicolao; Lineros, Roberto A.; Regis, Marco; Taoso, Marco

2014-04-01

We present an extensive analysis on the determination of the isotropic radio background. We consider six different radio maps, ranging from 22 MHz to 2.3 GHz and covering a large fraction of the sky. The large scale emission is modeled as a linear combination of an isotropic component plus the Galactic synchrotron radiation and thermal bremsstrahlung. Point-like and extended sources are either masked or accounted for by means of a template. We find a robust estimate of the isotropic radio background, with limited scatter among different Galactic models. The level of the isotropic background lies significantly above the contribution obtained by integrating the number counts of observed extragalactic sources. Since the isotropic component dominates at high latitudes, thus making the profile of the total emission flat, a Galactic origin for such excess appears unlikely. We conclude that, unless a systematic offset is present in the maps, and provided that our current understanding of the Galactic synchrotron emission is reasonable, extragalactic sources well below the current experimental threshold seem to account for the majority of the brightness of the extragalactic radio sky.

Non-perturbative background field calculations

NASA Astrophysics Data System (ADS)

Stephens, C. R.

1988-01-01

New methods are developed for calculating one loop functional determinants in quantum field theory. Instead of relying on a calculation of all the eigenvalues of the small fluctuation equation, these techniques exploit the ability of the proper time formalism to reformulate an infinite dimensional field theoretic problem into a finite dimensional covariant quantum mechanical analog, thereby allowing powerful tools such as the method of Jacobi fields to be used advantageously in a field theory setting. More generally the methods developed herein should be extremely valuable when calculating quantum processes in non-constant background fields, offering a utilitarian alternative to the two standard methods of calculation—perturbation theory in the background field or taking the background field into account exactly. The formalism developed also allows for the approximate calculation of covariances of partial differential equations from a knowledge of the solutions of a homogeneous ordinary differential equation.

Space moving target detection and tracking method in complex background

NASA Astrophysics Data System (ADS)

Lv, Ping-Yue; Sun, Sheng-Li; Lin, Chang-Qing; Liu, Gao-Rui

2018-06-01

The background of the space-borne detectors in real space-based environment is extremely complex and the signal-to-clutter ratio is very low (SCR ≈ 1), which increases the difficulty for detecting space moving targets. In order to solve this problem, an algorithm combining background suppression processing based on two-dimensional least mean square filter (TDLMS) and target enhancement based on neighborhood gray-scale difference (GSD) is proposed in this paper. The latter can filter out most of the residual background clutter processed by the former such as cloud edge. Through this procedure, both global and local SCR have obtained substantial improvement, indicating that the target has been greatly enhanced. After removing the detector's inherent clutter region through connected domain processing, the image only contains the target point and the isolated noise, in which the isolated noise could be filtered out effectively through multi-frame association. The proposed algorithm in this paper has been compared with some state-of-the-art algorithms for moving target detection and tracking tasks. The experimental results show that the performance of this algorithm is the best in terms of SCR gain, background suppression factor (BSF) and detection results.

Cosmic Microwave Background Mapmaking with a Messenger Field

NASA Astrophysics Data System (ADS)

Huffenberger, Kevin M.; Næss, Sigurd K.

2018-01-01

We apply a messenger field method to solve the linear minimum-variance mapmaking equation in the context of Cosmic Microwave Background (CMB) observations. In simulations, the method produces sky maps that converge significantly faster than those from a conjugate gradient descent algorithm with a diagonal preconditioner, even though the computational cost per iteration is similar. The messenger method recovers large scales in the map better than conjugate gradient descent, and yields a lower overall χ2. In the single, pencil beam approximation, each iteration of the messenger mapmaking procedure produces an unbiased map, and the iterations become more optimal as they proceed. A variant of the method can handle differential data or perform deconvolution mapmaking. The messenger method requires no preconditioner, but a high-quality solution needs a cooling parameter to control the convergence. We study the convergence properties of this new method and discuss how the algorithm is feasible for the large data sets of current and future CMB experiments.

Component separation of a isotropic Gravitational Wave Background

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

Parida, Abhishek; Jhingan, Sanjay; Mitra, Sanjit, E-mail: abhishek@jmi.ac.in, E-mail: sanjit@iucaa.in, E-mail: sjhingan@jmi.ac.in

2016-04-01

A Gravitational Wave Background (GWB) is expected in the universe from the superposition of a large number of unresolved astrophysical sources and phenomena in the early universe. Each component of the background (e.g., from primordial metric perturbations, binary neutron stars, milli-second pulsars etc.) has its own spectral shape. Many ongoing experiments aim to probe GWB at a variety of frequency bands. In the last two decades, using data from ground-based laser interferometric gravitational wave (GW) observatories, upper limits on GWB were placed in the frequency range of 0∼ 50−100 Hz, considering one spectral shape at a time. However, one strong componentmore » can significantly enhance the estimated strength of another component. Hence, estimation of the amplitudes of the components with different spectral shapes should be done jointly. Here we propose a method for 'component separation' of a statistically isotropic background, that can, for the first time, jointly estimate the amplitudes of many components and place upper limits. The method is rather straightforward and needs negligible amount of computation. It utilises the linear relationship between the measurements and the amplitudes of the actual components, alleviating the need for a sampling based method, e.g., Markov Chain Monte Carlo (MCMC) or matched filtering, which are computationally intensive and cumbersome in a multi-dimensional parameter space. Using this formalism we could also study how many independent components can be separated using a given dataset from a network of current and upcoming ground based interferometric detectors.« less

Helicopter Rotor Noise Prediction: Background, Current Status, and Future Direction

NASA Technical Reports Server (NTRS)

Brentner, Kenneth S.

1997-01-01

Helicopter noise prediction is increasingly important. The purpose of this viewgraph presentation is to: 1) Put into perspective the recent progress; 2) Outline current prediction capabilities; 3) Forecast direction of future prediction research; 4) Identify rotorcraft noise prediction needs. The presentation includes an historical perspective, a description of governing equations, and the current status of source noise prediction.

Measuring Attitude towards RE: Factoring Pupil Experience and Home Faith Background into Assessment

ERIC Educational Resources Information Center

Thanissaro, Phra Nicholas

2012-01-01

Recent studies have increasingly favoured contextualisation of religious education (RE) to pupils' home faith background in spite of current assessment methods that might hinder this. For a multi-religious, multi-ethnic sample of 369 London school pupils aged from 13 to 15 years, this study found that the participatory, transformative and…

Efficacy Evaluation of Current and Future Naval Mine Warfare Neutralization Method

DTIC Science & Technology

2016-12-01

Distribution is unlimited. EFFICACY EVALUATION OF CURRENT AND FUTURE NAVAL MINE WARFARE NEUTRALIZATION METHOD by Team MIW Cohort SE311-152O...EFFICACY EVALUATION OF CURRENT AND FUTURE NAVAL MINE WARFARE NEUTRALIZATION METHOD 5. FUNDING NUMBERS 6. AUTHOR (S) Team MIW, Systems Engineering...NEUTRALIZATION METHOD Team MIW, Systems Engineering Cohort SE311-152O Submitted in partial fulfillment of the requirements for the degrees of

Figures of merit for detectors in digital radiography. II. Finite number of secondaries and structured backgrounds.

PubMed

Pineda, Angel R; Barrett, Harrison H

2004-02-01

The current paradigm for evaluating detectors in digital radiography relies on Fourier methods. Fourier methods rely on a shift-invariant and statistically stationary description of the imaging system. The theoretical justification for the use of Fourier methods is based on a uniform background fluence and an infinite detector. In practice, the background fluence is not uniform and detector size is finite. We study the effect of stochastic blurring and structured backgrounds on the correlation between Fourier-based figures of merit and Hotelling detectability. A stochastic model of the blurring leads to behavior similar to what is observed by adding electronic noise to the deterministic blurring model. Background structure does away with the shift invariance. Anatomical variation makes the covariance matrix of the data less amenable to Fourier methods by introducing long-range correlations. It is desirable to have figures of merit that can account for all the sources of variation, some of which are not stationary. For such cases, we show that the commonly used figures of merit based on the discrete Fourier transform can provide an inaccurate estimate of Hotelling detectability.

Monte-Carlo background simulations of present and future detectors in x-ray astronomy

NASA Astrophysics Data System (ADS)

Tenzer, C.; Kendziorra, E.; Santangelo, A.

2008-07-01

Reaching a low-level and well understood internal instrumental background is crucial for the scientific performance of an X-ray detector and, therefore, a main objective of the instrument designers. Monte-Carlo simulations of the physics processes and interactions taking place in a space-based X-ray detector as a result of its orbital environment can be applied to explain the measured background of existing missions. They are thus an excellent tool to predict and optimize the background of future observatories. Weak points of a design and the main sources of the background can be identified and methods to reduce them can be implemented and studied within the simulations. Using the Geant4 Monte-Carlo toolkit, we have created a simulation environment for space-based detectors and we present results of such background simulations for XMM-Newton's EPIC pn-CCD camera. The environment is also currently used to estimate and optimize the background of the future instruments Simbol-X and eRosita.

Are South African Speech-Language Therapists adequately equipped to assess English Additional Language (EAL) speakers who are from an indigenous linguistic and cultural background? A profile and exploration of the current situation

PubMed Central

Mdlalo, Thandeka; Flack, Penelope

2016-01-01

This article presents the results of a survey conducted on Speech-Language Therapists (SLTs) regarding current practices in the assessment of English Additional Language (EAL) speakers in South Africa. It forms part of the rationale for a broader (PhD) study that critiques the use of assessment instruments on EAL speakers from an indigenous linguistic and cultural background. This article discusses an aspect of the broader research and presents the background, method, findings, discussion and implications of the survey. The results of this survey highlight the challenges of human and material resources to, and the dominance of English in, the profession in South Africa. The findings contribute to understanding critical factors for acquiring reliable and valid assessment results with diverse populations, particularly the implications from a cultural and linguistic perspective. PMID:27247254

Monotonicity based imaging method for time-domain eddy current problems

NASA Astrophysics Data System (ADS)

Su, Z.; Ventre, S.; Udpa, L.; Tamburrino, A.

2017-12-01

Eddy current imaging is an example of inverse problem in nondestructive evaluation for detecting anomalies in conducting materials. This paper introduces the concept of time constants and associated natural modes in eddy current imaging. The monotonicity of time constants is then described and applied to develop a non-iterative imaging method. The proposed imaging method has a low computational cost which makes it suitable for real-time operations. Full 3D numerical examples prove the effectiveness of the method in realistic scenarios. This paper is dedicated to Professor Guglielmo Rubinacci on the occasion of his 65th Birthday.

A new method to reduce the statistical and systematic uncertainty of chance coincidence backgrounds measured with waveform digitizers

DOE PAGES

O'Donnell, John M.

2015-06-30

We present a new method for measuring chance-coincidence backgrounds during the collection of coincidence data. The method relies on acquiring data with near-zero dead time, which is now realistic due to the increasing deployment of flash electronic-digitizer (waveform digitizer) techniques. An experiment designed to use this new method is capable of acquiring more coincidence data, and a much reduced statistical fluctuation of the measured background. A statistical analysis is presented, and us ed to derive a figure of merit for the new method. Factors of four improvement over other analyses are realistic. The technique is illustrated with preliminary data takenmore » as part of a program to make new measurements of the prompt fission neutron spectra at Los Alamo s Neutron Science Center. In conclusion, it is expected that the these measurements will occur in a regime where the maximum figure of merit will be exploited« less

Assessment of Complement Activation by Nanoparticles: Development of a SPR Based Method and Comparison with Current High Throughput Methods.

PubMed

Coty, Jean-Baptiste; Noiray, Magali; Vauthier, Christine

2018-04-26

A Surface Plasmon Resonance chip (SPR) was developed to study the activation of complement system triggered by nanomaterials in contact with human serum, which is an important concern today to warrant safety of nanomedicines. The developed chip was tested for its specificity in complex medium and its longevity of use. It was then employed to assess the release of complement fragments upon incubation of nanoparticles in serum. A comparison was made with other current methods assessing complement activation (μC-IE, ELISA). The SPR chip was found to give a consistent response for C3a release upon activation by nanoparticles. Results were similar to those obtained by μC-IE. However, ELISA detection of iC3b fragments showed an explained high non-specific background. The impact of sample preparation preceding the analysis was assessed with the newly develop SPR method. The removal of nanoparticles before analysis showed an important modification in the obtained response, possibly leading to false negative results. The SPR chip developed in this work allows for an automated assessment of complement activation triggered by nanoparticles with possibility of multiplexed analysis. The design of the chip proved to give consistent results of complement activation by nanoparticles.

Current Methods in Health Behavior Research Among U.S. Community College Students: A Review of the Literature

PubMed Central

Pokhrel, Pallav; Little, Melissa A.; Herzog, Thaddeus A.

2016-01-01

The majority of health behavior research involving college students in the United States has focused on 4-year college students. Two-year or community college students have been less studied, although a significant proportion of U.S. undergraduates, primarily those from disadvantaged socioeconomic and/or racial/ethnic background, are enrolled in community colleges. Thus, there is a need to enhance health behavior and health promotion research among community college students. This study systematically reviewed 42 published, peer-reviewed health behavior studies conducted among U.S. community college students in order to determine the current state of research in the area with regard to behaviors studied, research designs used, recruitment and data collection strategies practiced, rates of student participation, and characteristics of the participants represented. Findings identified the methodological limitations of current research and suggested optimal recruitment and data collection methods suitable for various research needs. Findings are discussed in the context of enhancing health behavior research among U.S. community college students. PMID:24227658

Optimization of advanced Wiener estimation methods for Raman reconstruction from narrow-band measurements in the presence of fluorescence background

PubMed Central

Chen, Shuo; Ong, Yi Hong; Lin, Xiaoqian; Liu, Quan

2015-01-01

Raman spectroscopy has shown great potential in biomedical applications. However, intrinsically weak Raman signals cause slow data acquisition especially in Raman imaging. This problem can be overcome by narrow-band Raman imaging followed by spectral reconstruction. Our previous study has shown that Raman spectra free of fluorescence background can be reconstructed from narrow-band Raman measurements using traditional Wiener estimation. However, fluorescence-free Raman spectra are only available from those sophisticated Raman setups capable of fluorescence suppression. The reconstruction of Raman spectra with fluorescence background from narrow-band measurements is much more challenging due to the significant variation in fluorescence background. In this study, two advanced Wiener estimation methods, i.e. modified Wiener estimation and sequential weighted Wiener estimation, were optimized to achieve this goal. Both spontaneous Raman spectra and surface enhanced Raman spectra were evaluated. Compared with traditional Wiener estimation, two advanced methods showed significant improvement in the reconstruction of spontaneous Raman spectra. However, traditional Wiener estimation can work as effectively as the advanced methods for SERS spectra but much faster. The wise selection of these methods would enable accurate Raman reconstruction in a simple Raman setup without the function of fluorescence suppression for fast Raman imaging. PMID:26203387

The Background to Current Theories of Scuffing

DTIC Science & Technology

1973-01-01

attention because, by neglecting axial flow , it can be treated in two dimensions. This has resulted in a fairly complete theoretical analysis...the contact. This method was essentially one of measuring the volume rate of flow through the contact, which was directly related to the pad...exit constriction. The pressure and temperature were also measured in the axial direction (105) and the results indicated that side leakage was

Focal plane infrared readout circuit with automatic background suppression

NASA Technical Reports Server (NTRS)

Pain, Bedabrata (Inventor); Yang, Guang (Inventor); Sun, Chao (Inventor); Shaw, Timothy J. (Inventor); Wrigley, Chris J. (Inventor)

2002-01-01

A circuit for reading out a signal from an infrared detector includes a current-mode background-signal subtracting circuit having a current memory which can be enabled to sample and store a dark level signal from the infrared detector during a calibration phase. The signal stored by the current memory is subtracted from a signal received from the infrared detector during an imaging phase. The circuit also includes a buffered direct injection input circuit and a differential voltage readout section. By performing most of the background signal estimation and subtraction in a current mode, a low gain can be provided by the buffered direct injection input circuit to keep the gain of the background signal relatively small, while a higher gain is provided by the differential voltage readout circuit. An array of such readout circuits can be used in an imager having an array of infrared detectors. The readout circuits can provide a high effective handling capacity.

Towards standardization of 18F-FET PET imaging: do we need a consistent method of background activity assessment?

PubMed

Unterrainer, Marcus; Vettermann, Franziska; Brendel, Matthias; Holzgreve, Adrien; Lifschitz, Michael; Zähringer, Matthias; Suchorska, Bogdana; Wenter, Vera; Illigens, Ben M; Bartenstein, Peter; Albert, Nathalie L

2017-12-01

PET with O-(2- 18 F-fluoroethyl)-L-tyrosine ( 18 F-FET) has reached increasing clinical significance for patients with brain neoplasms. For quantification of standard PET-derived parameters such as the tumor-to-background ratio, the background activity is assessed using a region of interest (ROI) or volume of interest (VOI) in unaffected brain tissue. However, there is no standardized approach regarding the assessment of the background reference. Therefore, we evaluated the intra- and inter-reader variability of commonly applied approaches for clinical 18 F-FET PET reading. The background activity of 20 18 F-FET PET scans was independently evaluated by 6 readers using a (i) simple 2D-ROI, (ii) spherical VOI with 3.0 cm diameter, and (iii) VOI consisting of crescent-shaped ROIs; each in the contralateral, non-affected hemisphere including white and gray matter in line with the European Association of Nuclear Medicine (EANM) and German guidelines. To assess intra-reader variability, each scan was evaluated 10 times by each reader. The coefficient of variation (CoV) was assessed for determination of intra- and inter-reader variability. In a second step, the best method was refined by instructions for a guided background activity assessment and validated by 10 further scans. Compared to the other approaches, the crescent-shaped VOIs revealed most stable results with the lowest intra-reader variabilities (median CoV 1.52%, spherical VOI 4.20%, 2D-ROI 3.69%; p < 0.001) and inter-reader variabilities (median CoV 2.14%, spherical VOI 4.02%, 2D-ROI 3.83%; p = 0.001). Using the guided background assessment, both intra-reader variabilities (median CoV 1.10%) and inter-reader variabilities (median CoV 1.19%) could be reduced even more. The commonly applied methods for background activity assessment show different variability which might hamper 18 F-FET PET quantification and comparability in multicenter settings. The proposed background activity assessment using a

Rectification of the background potassium current: a determinant of rotor dynamics in ventricular fibrillation.

PubMed

Samie, F H; Berenfeld, O; Anumonwo, J; Mironov, S F; Udassi, S; Beaumont, J; Taffet, S; Pertsov, A M; Jalife, J

2001-12-07

Ventricular fibrillation (VF) is the leading cause of sudden cardiac death. Yet, the mechanisms of VF remain elusive. Pixel-by-pixel spectral analysis of optical signals was carried out in video imaging experiments using a potentiometric dye in the Langendorff-perfused guinea pig heart. Dominant frequencies (peak with maximal power) were distributed throughout the ventricles in clearly demarcated domains. The fastest domain (25 to 32 Hz) was always on the anterior left ventricular (LV) wall and was shown to result from persistent rotor activity. Intermittent block and breakage of wavefronts at specific locations in the periphery of such rotors were responsible for the domain organization. Patch-clamping of ventricular myocytes from the LV and the right ventricle (RV) demonstrated an LV-to-RV drop in the amplitude of the outward component of the background rectifier current (I(B)). Computer simulations suggested that rotor stability in LV resulted from relatively small rectification of I(B) (presumably I(K1)), whereas instability, termination, and wavebreaks in RV were a consequence of strong rectification. This study provides new evidence in the isolated guinea pig heart that a persistent high-frequency rotor in the LV maintains VF, and that spatially distributed gradients in I(K1) density represent a robust ionic mechanism for rotor stabilization and wavefront fragmentation.

Method of minimizing the effects of parasitic currents

DOEpatents

Chi, Michael C.; Carr, Peter

1983-02-01

A method of minimizing the effect of parasitic currents in secondary batteries having a plurality of cells connected electrically in series and a common electrolyte in communication with the cells is described. Specifically, the parasitic currents flowing through the battery cause a cell imbalance over the charge/discharge cycle. This cell imbalance is minimized by first separating the cells of the battery into two equal groups. Then the battery is charged with the two groups of cells connected electrically in series, and subsequently discharged with the two groups of cells reconnected electrically in series in an inverted sequence.

Current-limited electron beam injection

NASA Technical Reports Server (NTRS)

Stenzel, R. L.

1977-01-01

The injection of an electron beam into a weakly collisional, magnetized background plasma was investigated experimentally. The injected beam was energetic and cold, the background plasma was initially isothermal. Beam and plasma dimensions were so large that the system was considered unbounded. The temporal and spatial evolution of the beam-plasma system was dominated by collective effects. High-frequency electrostatic instabilities rapidly thermalized the beam and heated the background electrons. The injected beam current was balanced by a return current consisting of background electrons drifting toward the beam source. The drift between electrons and ions gave rise to an ion acoustic instability which developed into strong three-dimensional turbulence. It was shown that the injected beam current was limited by the return current which is approximately given by the electron saturation current. Non-Maxwellian electron distribution functions were observed.

Method of making a current collector for a sodium/sulfur battery

DOEpatents

Tischer, R.P.; Winterbottom, W.L.; Wroblowa, H.S.

1987-03-10

This specification is directed to a method of making a current collector for a sodium/sulfur battery. The current collector so-made is electronically conductive and resistant to corrosive attack by sulfur/polysulfide melts. The method includes the step of forming the current collector for the sodium/sulfur battery from a composite material formed of aluminum filled with electronically conductive fibers selected from the group of fibers consisting essentially of graphite fibers having a diameter up to 10 microns and silicon carbide fibers having a diameter in a range of 500--1,000 angstroms. 2 figs.

Method of making a current collector for a sodium/sulfur battery

DOEpatents

Tischer, Ragnar P.; Winterbottom, Walter L.; Wroblowa, Halina S.

1987-01-01

This specification is directed to a method of making a current collector (14) for a sodium/sulfur battery (10). The current collector so-made is electronically conductive and resistant to corrosive attack by sulfur/polysulfide melts. The method includes the step of forming the current collector for the sodium/sulfur battery from a composite material (16) formed of aluminum filled with electronically conductive fibers selected from the group of fibers consisting essentially of graphite fibers having a diameter up to 10 microns and silicon carbide fibers having a diameter in a range of 500-1000 angstroms.

Numerical simulation of inductive method for determining spatial distribution of critical current density

NASA Astrophysics Data System (ADS)

Kamitani, A.; Takayama, T.; Tanaka, A.; Ikuno, S.

2010-11-01

The inductive method for measuring the critical current density jC in a high-temperature superconducting (HTS) thin film has been investigated numerically. In order to simulate the method, a non-axisymmetric numerical code has been developed for analyzing the time evolution of the shielding current density. In the code, the governing equation of the shielding current density is spatially discretized with the finite element method and the resulting first-order ordinary differential system is solved by using the 5th-order Runge-Kutta method with an adaptive step-size control algorithm. By using the code, the threshold current IT is evaluated for various positions of a coil. The results of computations show that, near a film edge, the accuracy of the estimating formula for jC is remarkably degraded. Moreover, even the proportional relationship between jC and IT will be lost there. Hence, the critical current density near a film edge cannot be estimated by using the inductive method.

Gravitational-wave stochastic background from cosmic strings.

PubMed

Siemens, Xavier; Mandic, Vuk; Creighton, Jolien

2007-03-16

We consider the stochastic background of gravitational waves produced by a network of cosmic strings and assess their accessibility to current and planned gravitational wave detectors, as well as to big bang nucleosynthesis (BBN), cosmic microwave background (CMB), and pulsar timing constraints. We find that current data from interferometric gravitational wave detectors, such as Laser Interferometer Gravitational Wave Observatory (LIGO), are sensitive to areas of parameter space of cosmic string models complementary to those accessible to pulsar, BBN, and CMB bounds. Future more sensitive LIGO runs and interferometers such as Advanced LIGO and Laser Interferometer Space Antenna (LISA) will be able to explore substantial parts of the parameter space.

Effect of background dielectric on TE-polarized photonic bandgap of metallodielectric photonic crystals using Dirichlet-to-Neumann map method.

PubMed

Sedghi, Aliasghar; Rezaei, Behrooz

2016-11-20

Using the Dirichlet-to-Neumann map method, we have calculated the photonic band structure of two-dimensional metallodielectric photonic crystals having the square and triangular lattices of circular metal rods in a dielectric background. We have selected the transverse electric mode of electromagnetic waves, and the resulting band structures showed the existence of photonic bandgap in these structures. We theoretically study the effect of background dielectric on the photonic bandgap.

Expected background in the LZ experiment

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

Kudryavtsev, Vitaly A.

2015-08-17

The LZ experiment, featuring a 7-tonne active liquid xenon target, is aimed at achieving unprecedented sensitivity to WIMPs with the background expected to be dominated by astrophysical neutrinos. To reach this goal, extensive simulations are carried out to accurately calculate the electron recoil and nuclear recoil rates in the detector. Both internal (from target material) and external (from detector components and surrounding environment) backgrounds are considered. A very efficient suppression of background rate is achieved with an outer liquid scintillator veto, liquid xenon skin and fiducialisation. Based on the current measurements of radioactivity of different materials, it is shown thatmore » LZ can achieve the reduction of a total background for a WIMP search down to about 2 events in 1000 live days for 5.6 tonne fiducial mass.« less

Expected background in the LZ experiment

NASA Astrophysics Data System (ADS)

Kudryavtsev, Vitaly A.

2015-08-01

The LZ experiment, featuring a 7-tonne active liquid xenon target, is aimed at achieving unprecedented sensitivity to WIMPs with the background expected to be dominated by astrophysical neutrinos. To reach this goal, extensive simulations are carried out to accurately calculate the electron recoil and nuclear recoil rates in the detector. Both internal (from target material) and external (from detector components and surrounding environment) backgrounds are considered. A very efficient suppression of background rate is achieved with an outer liquid scintillator veto, liquid xenon skin and fiducialisation. Based on the current measurements of radioactivity of different materials, it is shown that LZ can achieve the reduction of a total background for a WIMP search down to about 2 events in 1000 live days for 5.6 tonne fiducial mass.

Detecting background changes in environments with dynamic foreground by separating probability distribution function mixtures using Pearson's method of moments

NASA Astrophysics Data System (ADS)

Jenkins, Colleen; Jordan, Jay; Carlson, Jeff

2007-02-01

This paper presents parameter estimation techniques useful for detecting background changes in a video sequence with extreme foreground activity. A specific application of interest is automated detection of the covert placement of threats (e.g., a briefcase bomb) inside crowded public facilities. We propose that a histogram of pixel intensity acquired from a fixed mounted camera over time for a series of images will be a mixture of two Gaussian functions: the foreground probability distribution function and background probability distribution function. We will use Pearson's Method of Moments to separate the two probability distribution functions. The background function can then be "remembered" and changes in the background can be detected. Subsequent comparisons of background estimates are used to detect changes. Changes are flagged to alert security forces to the presence and location of potential threats. Results are presented that indicate the significant potential for robust parameter estimation techniques as applied to video surveillance.

Background recovery via motion-based robust principal component analysis with matrix factorization

NASA Astrophysics Data System (ADS)

Pan, Peng; Wang, Yongli; Zhou, Mingyuan; Sun, Zhipeng; He, Guoping

2018-03-01

Background recovery is a key technique in video analysis, but it still suffers from many challenges, such as camouflage, lighting changes, and diverse types of image noise. Robust principal component analysis (RPCA), which aims to recover a low-rank matrix and a sparse matrix, is a general framework for background recovery. The nuclear norm is widely used as a convex surrogate for the rank function in RPCA, which requires computing the singular value decomposition (SVD), a task that is increasingly costly as matrix sizes and ranks increase. However, matrix factorization greatly reduces the dimension of the matrix for which the SVD must be computed. Motion information has been shown to improve low-rank matrix recovery in RPCA, but this method still finds it difficult to handle original video data sets because of its batch-mode formulation and implementation. Hence, in this paper, we propose a motion-assisted RPCA model with matrix factorization (FM-RPCA) for background recovery. Moreover, an efficient linear alternating direction method of multipliers with a matrix factorization (FL-ADM) algorithm is designed for solving the proposed FM-RPCA model. Experimental results illustrate that the method provides stable results and is more efficient than the current state-of-the-art algorithms.

Skyrmion based universal memory operated by electric current

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

Zang, Jiadong; Chien, Chia-Ling; Li, Yufan

2017-09-26

A method for generating a skyrmion, comprising: depositing a vertical metallic nanopillar electrode on a first side of a helimagnetic thin film, the helimagnetic thin film having a contact on a second side to provide a current drain; injecting a current through the vertical metallic nanopillar electrode to generate a rotating field; and applying a static upward magnetic field perpendicular to the helimagnetic thin film to maintain an FM phase background.

Anisotropic quantum quench in the presence of frustration or background gauge fields: A probe of bulk currents and topological chiral edge modes

NASA Astrophysics Data System (ADS)

Killi, Matthew; Trotzky, Stefan; Paramekanti, Arun

2012-12-01

Bosons and fermions, in the presence of frustration or background gauge fields, can form many-body ground states that support equilibrium charge or spin currents. Motivated by the experimental creation of frustration or synthetic gauge fields in ultracold atomic systems, we propose a general scheme by which making a sudden anisotropic quench of the atom tunneling across the lattice and tracking the ensuing density modulations provides a powerful and gauge-invariant route to probing diverse equilibrium current patterns. Using illustrative examples of trapped superfluid Bose and normal Fermi systems in the presence of artificial magnetic fluxes on square lattices, and frustrated bosons in a triangular lattice, we show that this scheme to probe equilibrium bulk current order works independent of particle statistics. We also show that such quenches can detect chiral edge modes in gapped topological states, such as quantum Hall or quantum spin Hall insulators.

Validation of a New Placebo Interferential Current Method: A New Placebo Method of Electrostimulation.

PubMed

Mendonça Araújo, Fernanda; Alves Menezes, Mayara; Martins de Araújo, Ariane; Abner Dos Santos Sousa, Thiago; Vasconcelos Lima, Lucas; Ádan Nunes Carvalho, Elyson; Melo DeSantana, Josimari

2017-01-01

The present study aimed to investigate if a new placebo device for interferential current (IFC) that delivers current during only the first 40 seconds of stimulation is effective at promoting adequate subject blinding. Seventy-five subjects were recruited and enrolled into three groups: active IFC, inactive placebo, and new placebo. Pressure pain threshold (PPT), cutaneous sensory threshold (CST), and pain intensity were measured before and after the intervention. After the final assessment, the subjects and the investigator who applied the current were asked about the type of stimulation administered. None of the placebo forms studied resulted in significant changes to PPT, CST, or pain intensity. The subjects stimulated with active IFC at high intensities (> 17 mA) of stimulation showed higher PPT and CST and lower pain intensity than subjects stimulated at low intensities ( p < 0.03). The new placebo method blinded the investigator in 100% of cases of IFC and 60% of subjects stimulated, whereas for inactive placebo, the investigator was blinded at a rate of 0% and 34% of subjects. The new method of placebo IFC was effective for blinding of research investigators and most of the active IFC-treated subjects, promoting an appropriate placebo method. © 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Current On-Campus Attitudes toward Energy Usage, Efficiency, and Emerging Technologies

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

Lennon, Liz; Sintov, Nicole; Orosz, Michael

Context & Background for Energy Survey Methods & Survey Overview Respondent Demographics Results Demand Response Current Environmental Comfort Perceptions Smart Meters Perceived Smart Meter Benefits Motivators of Energy Efficient Practices Summary & Implications

Robust constraint on cosmic textures from the cosmic microwave background.

PubMed

Feeney, Stephen M; Johnson, Matthew C; Mortlock, Daniel J; Peiris, Hiranya V

2012-06-15

Fluctuations in the cosmic microwave background (CMB) contain information which has been pivotal in establishing the current cosmological model. These data can also be used to test well-motivated additions to this model, such as cosmic textures. Textures are a type of topological defect that can be produced during a cosmological phase transition in the early Universe, and which leave characteristic hot and cold spots in the CMB. We apply bayesian methods to carry out a rigorous test of the texture hypothesis, using full-sky data from the Wilkinson Microwave Anisotropy Probe. We conclude that current data do not warrant augmenting the standard cosmological model with textures. We rule out at 95% confidence models that predict more than 6 detectable cosmic textures on the full sky.

Method and apparatus to trigger superconductors in current limiting devices

DOEpatents

Yuan, Xing; Hazelton, Drew Willard; Walker, Michael Stephen

2004-10-26

A method and apparatus for magnetically triggering a superconductor in a superconducting fault current limiter to transition from a superconducting state to a resistive state. The triggering is achieved by employing current-carrying trigger coil or foil on either or both the inner diameter and outer diameter of a superconductor. The current-carrying coil or foil generates a magnetic field with sufficient strength and the superconductor is disposed within essentially uniform magnetic field region. For superconductor in a tubular-configured form, an additional magnetic field can be generated by placing current-carrying wire or foil inside the tube and along the center axial line.

An Automated Method for High-Definition Transcranial Direct Current Stimulation Modeling*

PubMed Central

Huang, Yu; Su, Yuzhuo; Rorden, Christopher; Dmochowski, Jacek; Datta, Abhishek; Parra, Lucas C.

2014-01-01

Targeted transcranial stimulation with electric currents requires accurate models of the current flow from scalp electrodes to the human brain. Idiosyncratic anatomy of individual brains and heads leads to significant variability in such current flows across subjects, thus, necessitating accurate individualized head models. Here we report on an automated processing chain that computes current distributions in the head starting from a structural magnetic resonance image (MRI). The main purpose of automating this process is to reduce the substantial effort currently required for manual segmentation, electrode placement, and solving of finite element models. In doing so, several weeks of manual labor were reduced to no more than 4 hours of computation time and minimal user interaction, while current-flow results for the automated method deviated by less than 27.9% from the manual method. Key facilitating factors are the addition of three tissue types (skull, scalp and air) to a state-of-the-art automated segmentation process, morphological processing to correct small but important segmentation errors, and automated placement of small electrodes based on easily reproducible standard electrode configurations. We anticipate that such an automated processing will become an indispensable tool to individualize transcranial direct current stimulation (tDCS) therapy. PMID:23367144

A new background subtraction method for Western blot densitometry band quantification through image analysis software.

PubMed

Gallo-Oller, Gabriel; Ordoñez, Raquel; Dotor, Javier

2018-06-01

Since its first description, Western blot has been widely used in molecular labs. It constitutes a multistep method that allows the detection and/or quantification of proteins from simple to complex protein mixtures. Western blot quantification method constitutes a critical step in order to obtain accurate and reproducible results. Due to the technical knowledge required for densitometry analysis together with the resources availability, standard office scanners are often used for the imaging acquisition of developed Western blot films. Furthermore, the use of semi-quantitative software as ImageJ (Java-based image-processing and analysis software) is clearly increasing in different scientific fields. In this work, we describe the use of office scanner coupled with the ImageJ software together with a new image background subtraction method for accurate Western blot quantification. The proposed method represents an affordable, accurate and reproducible approximation that could be used in the presence of limited resources availability. Copyright © 2018 Elsevier B.V. All rights reserved.

Evaluation of Shifted Excitation Raman Difference Spectroscopy and Comparison to Computational Background Correction Methods Applied to Biochemical Raman Spectra.

PubMed

Cordero, Eliana; Korinth, Florian; Stiebing, Clara; Krafft, Christoph; Schie, Iwan W; Popp, Jürgen

2017-07-27

Raman spectroscopy provides label-free biochemical information from tissue samples without complicated sample preparation. The clinical capability of Raman spectroscopy has been demonstrated in a wide range of in vitro and in vivo applications. However, a challenge for in vivo applications is the simultaneous excitation of auto-fluorescence in the majority of tissues of interest, such as liver, bladder, brain, and others. Raman bands are then superimposed on a fluorescence background, which can be several orders of magnitude larger than the Raman signal. To eliminate the disturbing fluorescence background, several approaches are available. Among instrumentational methods shifted excitation Raman difference spectroscopy (SERDS) has been widely applied and studied. Similarly, computational techniques, for instance extended multiplicative scatter correction (EMSC), have also been employed to remove undesired background contributions. Here, we present a theoretical and experimental evaluation and comparison of fluorescence background removal approaches for Raman spectra based on SERDS and EMSC.

76 FR 71934 - Tobacco Transition Payment Program; Availability of Current Assessment Methods Determination...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-21

... DEPARTMENT OF AGRICULTURE Farm Service Agency Tobacco Transition Payment Program; Availability of Current Assessment Methods Determination Document AGENCY: Commodity Credit Corporation and Farm Service... current methods used to calculate manufacturer and importer assessments that fund the Tobacco Transition...

Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

DTIC Science & Technology

2008-04-30

resumed testing, and has no plans to test. It has reduced the time needed to conduct a nuclear test. Critics raised concerns about the implications of...lieu of the current treaty.1 On October 24, Senator Jon Kyl delivered a speech critical of the CTBT and of Section 3122 in H.R. 1585, the FY2008...2007. Critics expressed concern about the implications of these policies for testing and new weapons. A statement by Physicians for Social

Impact of long-pass interferential filters on dark current and background light rejection in Silicon Photomultipliers

NASA Astrophysics Data System (ADS)

Mazzillo, M.; Sciuto, A.; Libertino, S.; Lombardo, S.; Fallica, G.

2018-02-01

There is an increasing interest in using Silicon Photomultipliers (SiPMs) in emerging applications where the detectors have to operate in ambient environment with high sensitivity and fast timing response in combination with narrow bandwidth light emitting sources like LEDs or VCSELs. The need to use large area detectors for optimizing the light collection efficiency, due to the low optical fluxes to be usually detected, imposes the optimization of the SiPM performance in specific wavelength ranges (usually visible or near infrared), to fully exploit the single photon sensitivity of these detectors and not to reduce at the same time their dynamic range. The use of proper optical long-pass filters on the detector's package can represent a suitable way to reach both these targets, through the reduction of environmental light absorption. Here we present the preliminary results obtained from the characterization of n+-p SiPMs with commercial long-pass filters with increasing cut-on wavelength in the range 500 nm-900 nm glued on the top side of the detector's package. The performance of the detectors has been evaluated in terms of dark current variation induced by the use of the filters and background light rejection under the illumination of white fluorescent lamps. The relevant reduction observed in the dark current (up to 90% at 13 V overvoltage) and the consistent reduction of stray light absorption (up to 90% at 3 V overvoltage with a 900 nm cut-on wavelength long-pass filter) are the main characterization results obtained and shown in this paper.

Background feature descriptor for offline handwritten numeral recognition

NASA Astrophysics Data System (ADS)

Ming, Delie; Wang, Hao; Tian, Tian; Jie, Feiran; Lei, Bo

2011-11-01

This paper puts forward an offline handwritten numeral recognition method based on background structural descriptor (sixteen-value numerical background expression). Through encoding the background pixels in the image according to a certain rule, 16 different eigenvalues were generated, which reflected the background condition of every digit, then reflected the structural features of the digits. Through pattern language description of images by these features, automatic segmentation of overlapping digits and numeral recognition can be realized. This method is characterized by great deformation resistant ability, high recognition speed and easy realization. Finally, the experimental results and conclusions are presented. The experimental results of recognizing datasets from various practical application fields reflect that with this method, a good recognition effect can be achieved.

[Study on the method for the determination of trace boron, molybdenum, silver, tin and lead in geochemical samples by direct current arc full spectrum direct reading atomic emission spectroscopy (DC-Arc-AES)].

PubMed

Hao, Zhi-hong; Yao, Jian-zhen; Tang, Rui-ling; Zhang, Xue-mei; Li, Wen-ge; Zhang, Qin

2015-02-01

The method for the determmation of trace boron, molybdenum, silver, tin and lead in geochemical samples by direct current are full spectrum direct reading atomic emission spectroscopy (DC-Arc-AES) was established. Direct current are full spectrum direct reading atomic emission spectrometer with a large area of solid-state detectors has functions of full spectrum direct reading and real-time background correction. The new electrodes and new buffer recipe were proposed in this paper, and have applied for national patent. Suitable analytical line pairs, back ground correcting points of elements and the internal standard method were selected, and Ge was used as internal standard. Multistage currents were selected in the research on current program, and each current set different holding time to ensure that each element has a good signal to noise ratio. Continuous rising current mode selected can effectively eliminate the splash of the sample. Argon as shielding gas can eliminate CN band generating and reduce spectral background, also plays a role in stabilizing the are, and argon flow 3.5 L x min(-1) was selected. Evaporation curve of each element was made, and it was concluded that the evaporation behavior of each element is consistent, and combined with the effects of different spectrographic times on the intensity and background, the spectrographic time of 35s was selected. In this paper, national standards substances were selected as a standard series, and the standard series includes different nature and different content of standard substances which meet the determination of trace boron, molybdenum, silver, tin and lead in geochemical samples. In the optimum experimental conditions, the detection limits for B, Mo, Ag, Sn and Pb are 1.1, 0.09, 0.01, 0.41, and 0.56 microg x g(-1) respectively, and the precisions (RSD, n=12) for B, Mo, Ag, Sn and Pb are 4.57%-7.63%, 5.14%-7.75%, 5.48%-12.30%, 3.97%-10.46%, and 4.26%-9.21% respectively. The analytical accuracy was

Research on the algorithm of infrared target detection based on the frame difference and background subtraction method

NASA Astrophysics Data System (ADS)

Liu, Yun; Zhao, Yuejin; Liu, Ming; Dong, Liquan; Hui, Mei; Liu, Xiaohua; Wu, Yijian

2015-09-01

As an important branch of infrared imaging technology, infrared target tracking and detection has a very important scientific value and a wide range of applications in both military and civilian areas. For the infrared image which is characterized by low SNR and serious disturbance of background noise, an innovative and effective target detection algorithm is proposed in this paper, according to the correlation of moving target frame-to-frame and the irrelevance of noise in sequential images based on OpenCV. Firstly, since the temporal differencing and background subtraction are very complementary, we use a combined detection method of frame difference and background subtraction which is based on adaptive background updating. Results indicate that it is simple and can extract the foreground moving target from the video sequence stably. For the background updating mechanism continuously updating each pixel, we can detect the infrared moving target more accurately. It paves the way for eventually realizing real-time infrared target detection and tracking, when transplanting the algorithms on OpenCV to the DSP platform. Afterwards, we use the optimal thresholding arithmetic to segment image. It transforms the gray images to black-white images in order to provide a better condition for the image sequences detection. Finally, according to the relevance of moving objects between different frames and mathematical morphology processing, we can eliminate noise, decrease the area, and smooth region boundaries. Experimental results proves that our algorithm precisely achieve the purpose of rapid detection of small infrared target.

Direct-current arc and alternating-current spark emission spectrographic field methods for the semiquantitative analysis of geologic materials

USGS Publications Warehouse

Grimes, D.J.; Marranzino, A.P.

1968-01-01

Two spectrographic methods are used in mobile field laboratories of the U. S. Geological Survey. In the direct-current arc method, the ground sample is mixed with graphite powder, packed into an electrode crater, and burned to completion. Thirty elements are determined. In the spark method, the sample, ground to pass a 150-mesh screen, is digested in hydrofluoric acid followed by evaporation to dryness and dissolution in aqua regia. The solution is fed into the spark gap by means of a rotating-disk electrode arrangement and is excited with an alternating-current spark discharge. Fourteen elements are determined. In both techniques, light is recorded on Spectrum Analysis No. 1, 35-millimeter film, and the spectra are compared visually with those of standard films.

Evaluation of aerosol sources at European high altitude background sites with trajectory statistical methods

NASA Astrophysics Data System (ADS)

Salvador, P.; Artíñano, B.; Pio, C. A.; Afonso, J.; Puxbaum, H.; Legrand, M.; Hammer, S.; Kaiser, A.

2009-04-01

countries). Secondary organic aerosol carbon formed by the photo-oxidation of biogenic emissions mainly from Germany, seems to be predominant in this season. This seasonal cycle is mainly driven by the winter/summer contrast of the regional-scale vertical mixing. During the warm season the vertical air mass exchange is enhanced by a more efficient upward transport from the boundary layer to the mountain sites. During the winter months, the vertical mixing intensity is reduced. In this season the mean levels obtained for OC and EC were lower than those recorded during the summer. Their spatiotemporal variability was mainly governed by air mass transport from distant regions, especially from Eastern Europe regions, where significant amounts of fossil fuels and biomass are currently consumed. Furthermore, emissions from desert regions in North Africa seemed to significantly influence the central European background mineral aerosol concentrations throughout the year. References: Pio C. A., M. Legrand, T. Oliveira, J. Afonso, C. Santos, A. Caseiro, P. Fialho, F. Barata, H. Puxbaum, A. Sanchez-Ochoa, A. Kasper-Giebl, A. Gelencsér, S. Preunkert, and M. Schock (2007), Climatology of aerosol composition (organic versus inorganic) at nonurban sites on a west-east transect across Europe. J. Geophys. Res., 112, D23S02, doi:10.1029/2006JD008038. Stohl A., G. Wotawa, P. Seibert and H. Kromp-Kolb (1995), Interpolation errors in wind fields as a function of spatial and temporal resolution and their impact on different types of kinematic trajectories. J. Appl. Meteorol., 34, 2149-2165. Stohl A. (1996), Trajectory statistics-a new method to establish source-receptor relationships of air pollutants and its application to the transport of particulate sulfate in Europe. Atmos. Environ., 30(4), 579-587.

Method for producing silicon thin-film transistors with enhanced forward current drive

DOEpatents

Weiner, Kurt H.

1998-01-01

A method for fabricating amorphous silicon thin film transistors (TFTs) with a polycrystalline silicon surface channel region for enhanced forward current drive. The method is particularly adapted for producing top-gate silicon TFTs which have the advantages of both amorphous and polycrystalline silicon TFTs, but without problem of leakage current of polycrystalline silicon TFTs. This is accomplished by selectively crystallizing a selected region of the amorphous silicon, using a pulsed excimer laser, to create a thin polycrystalline silicon layer at the silicon/gate-insulator surface. The thus created polysilicon layer has an increased mobility compared to the amorphous silicon during forward device operation so that increased drive currents are achieved. In reverse operation the polysilicon layer is relatively thin compared to the amorphous silicon, so that the transistor exhibits the low leakage currents inherent to amorphous silicon. A device made by this method can be used, for example, as a pixel switch in an active-matrix liquid crystal display to improve display refresh rates.

Urban Background Study Webinar

EPA Pesticide Factsheets

This webinar presented the methodology developed for collecting a city-wide or urban area background data set, general results of southeastern cities data collected to date, and a case study that used this sampling method.

The Current Status of Peer Assessment Techniques and Sociometric Methods

ERIC Educational Resources Information Center

Bukowski, William M.; Castellanos, Melisa; Persram, Ryan J.

2017-01-01

Current issues in the use of peer assessment techniques and sociometric methods are discussed. Attention is paid to the contributions of the four articles in this volume. Together these contributions point to the continual level of change and progress in these techniques. They also show that the paradigm underlying these methods has been unchanged…

An accelerated lambda iteration method for multilevel radiative transfer. I - Non-overlapping lines with background continuum

NASA Technical Reports Server (NTRS)

Rybicki, G. B.; Hummer, D. G.

1991-01-01

A method is presented for solving multilevel transfer problems when nonoverlapping lines and background continuum are present and active continuum transfer is absent. An approximate lambda operator is employed to derive linear, 'preconditioned', statistical-equilibrium equations. A method is described for finding the diagonal elements of the 'true' numerical lambda operator, and therefore for obtaining the coefficients of the equations. Iterations of the preconditioned equations, in conjunction with the transfer equation's formal solution, are used to solve linear equations. Some multilevel problems are considered, including an eleven-level neutral helium atom. Diagonal and tridiagonal approximate lambda operators are utilized in the problems to examine the convergence properties of the method, and it is found to be effective for the line transfer problems.

Evaluation of Shifted Excitation Raman Difference Spectroscopy and Comparison to Computational Background Correction Methods Applied to Biochemical Raman Spectra

PubMed Central

Cordero, Eliana; Korinth, Florian; Stiebing, Clara; Krafft, Christoph; Schie, Iwan W.; Popp, Jürgen

2017-01-01

Raman spectroscopy provides label-free biochemical information from tissue samples without complicated sample preparation. The clinical capability of Raman spectroscopy has been demonstrated in a wide range of in vitro and in vivo applications. However, a challenge for in vivo applications is the simultaneous excitation of auto-fluorescence in the majority of tissues of interest, such as liver, bladder, brain, and others. Raman bands are then superimposed on a fluorescence background, which can be several orders of magnitude larger than the Raman signal. To eliminate the disturbing fluorescence background, several approaches are available. Among instrumentational methods shifted excitation Raman difference spectroscopy (SERDS) has been widely applied and studied. Similarly, computational techniques, for instance extended multiplicative scatter correction (EMSC), have also been employed to remove undesired background contributions. Here, we present a theoretical and experimental evaluation and comparison of fluorescence background removal approaches for Raman spectra based on SERDS and EMSC. PMID:28749450

The EPIC-MOS Particle-Induced Background Spectrum

NASA Technical Reports Server (NTRS)

Kuntz, K. D.; Snowden, S. L.

2006-01-01

We have developed a method for constructing a spectrum of the particle-induced instrumental background of the XMM-Newton EPIC MOS detectors that can be used for observations of the diffuse background and extended sources that fill a significant fraction of the instrument field of view. The strength and spectrum of the particle-induced background, that is, the background due to the interaction of particles with the detector and the detector surroundings, is temporally variable as well as spatially variable over individual chips. Our method uses a combination of the filter-wheel-closed data and a database of unexposed-region data to construct a spectrum of the "quiescent" background. We show that, using this method of background subtraction, the differences between independent observations of the same region of "blank sky" are consistent with the statistical uncertainties except when there is clear evidence of solar wind charge exchange emission. We use the blank sky observations to show that contamination by SWCX emission is a strong function of the solar wind proton flux, and that observations through the flanks of the magnetosheath appear to be contaminated only at much higher solar wind fluxes. We have also developed a spectral model of the residual soft proton flares, which allows their effects to be removed to a substantial degree during spectral fitting.

The Enterococcus QPCR Method for Recreational Water Quality Testing: Testing Background, Performance and Issues

EPA Science Inventory

Currently accepted culture-based monitoring methods for fecal indicator bacteria in surface waters take at least 24 hr to determine if unacceptable levels of fecal pollution have reached our recreational beaches. During this waiting period changing water conditions may result eit...

Commentary: criminal background checks for entering medical students: history, current issues, and future considerations.

PubMed

Kleshinski, James; Case, Steven T; Davis, Dwight; Heinrich, George F; Witzburg, Robert A

2011-07-01

In this commentary, the authors aim to contextualize the history and rationale for what has become the Association of American Medical Colleges-facilitated criminal background check process for entering medical students. As the process was being considered, many issues with a standardized process were identified. There were concerns that demographic or socioeconomic factors might unfairly burden certain applicants or discourage them from applying to medical school. On the other hand, a unified, national program would minimize cost and enhance quality assurance. The authors discuss these issues. Lessons learned in the first three years of the program are also addressed, including some unexpected and favorable consequences such as the identification of accepted applicants with at-risk behaviors (e.g., substance abuse), who would have otherwise gone undetected. Several challenges remain, including the fact that the criminal background check process creates an enhanced role for prehealth advisors and encourages undergraduate institutions to establish standards and processes relating to professionalism. While this is, no doubt, an evolving program which needs continued oversight and ongoing reevaluation, the authors support the continued advancement of the criminal background check process for entering medical students.

[Zhu Lian's cognition on theory and method of acupuncture and moxibustion under background of western medicine].

PubMed

Li, Su-yun; Zhang, Li-jian; Liu, Bing

2014-11-01

With new acupuncture and moxibustion as the study object, based on the basic composition of acupuncture-moxibustion theory, from 3 aspects of meridian-acupoint theory, acupuncture-moxibustion method theory and acupuncture-moxibustion treatment theory, under the background of western medicine, ZHU Lian's different opinions on theory and method of acupuncture and moxibustion were discussed. It was believed by ZHU Lian that the distribution of 14-meridians was approximately identical to that of nerves, so with modern neuroanatomy knowledge to understand the meaning of acupoint; the acupuncture function could be explained from the angle of neurophysiology. Clinical diagnosis and treatment method could be established by modern classification methods of diseases. ZHU Lian's cognition that was different from traditional theory and method of acupuncture and moxibustion was combined with updated physiology and anatomy knowledge at that time, and was involved with Pavlov's advanced nerve theory, so she firstly put forward the opinion that acupuncture therapy can't work without the involvement of cerebral cortex.

Implementation of a chemical background method (OH-CHEM) for measurements of OH using the Leeds FAGE instrument: Characterisation and observations from a coastal location

NASA Astrophysics Data System (ADS)

Woodward-Massey, R.; Cryer, D. R.; Whalley, L. K.; Ingham, T.; Seakins, P. W.; Heard, D. E.; Stimpson, L. M.

2015-12-01

The removal of pollutants and greenhouse gases in the troposphere is dominated by reactions with the hydroxyl radical (OH), which is closely coupled to the hydroperoxy radical (HO2). Comparisons of the levels of OH and HO2 observed during field campaigns to the results of detailed chemical box models serve as a vital tool to assess our understanding of the underlying chemical mechanisms involved in tropospheric oxidation. Recent measurements of OH and HO2 radicals are significantly higher than those predicted by models for some instruments measuring in certain environments, especially those influenced by high emissions of biogenic compounds such as isoprene, prompting intense laboratory research to account for such discrepancies. While current chemical mechanisms are likely incomplete, it is also possible that, at least in part, these elevated radical observations have been influenced by instrumental biases from interfering species. Recent studies have suggested that fluorescence assay by gas expansion (FAGE) instruments may be susceptible to an unknown interference in the measurement of OH. This hypothesis can be tested through the implementation of an alternative method to determine the OH background signal, whereby OH is removed by the addition of a chemical scavenger prior to sampling by FAGE. The Leeds FAGE instrument was modified to facilitate this method by the construction of an inlet pre-injector (IPI), where OH is removed through reaction with propane. The modified Leeds FAGE instrument was deployed at a coastal location in southeast England during summer 2015 as part of the ICOZA (Integrated Chemistry of OZone in the Atmosphere) project. Measurements of OH made using both background methods will be presented, alongside results from laboratory characterisation experiments and details of the IPI design.

Comparing DIF Methods for Data with Dual Dependency

ERIC Educational Resources Information Center

Jin, Ying; Kang, Minsoo

2016-01-01

Background: The current study compared four differential item functioning (DIF) methods to examine their performances in terms of accounting for dual dependency (i.e., person and item clustering effects) simultaneously by a simulation study, which is not sufficiently studied under the current DIF literature. The four methods compared are logistic…

Method for producing silicon thin-film transistors with enhanced forward current drive

DOEpatents

Weiner, K.H.

1998-06-30

A method is disclosed for fabricating amorphous silicon thin film transistors (TFTs) with a polycrystalline silicon surface channel region for enhanced forward current drive. The method is particularly adapted for producing top-gate silicon TFTs which have the advantages of both amorphous and polycrystalline silicon TFTs, but without problem of leakage current of polycrystalline silicon TFTs. This is accomplished by selectively crystallizing a selected region of the amorphous silicon, using a pulsed excimer laser, to create a thin polycrystalline silicon layer at the silicon/gate-insulator surface. The thus created polysilicon layer has an increased mobility compared to the amorphous silicon during forward device operation so that increased drive currents are achieved. In reverse operation the polysilicon layer is relatively thin compared to the amorphous silicon, so that the transistor exhibits the low leakage currents inherent to amorphous silicon. A device made by this method can be used, for example, as a pixel switch in an active-matrix liquid crystal display to improve display refresh rates. 1 fig.

Firearm Acquisition Without Background Checks: Results of a National Survey.

PubMed

Miller, Matthew; Hepburn, Lisa; Azrael, Deborah

2017-02-21

In 1994, 40% of U.S. gun owners who had recently acquired a firearm did so without a background check. No contemporary estimates exist. To estimate the proportion of current U.S. gun owners who acquired their most recent firearm without a background check, by time since and manner of acquisition, for the nation as a whole and separately in states with and without legislation regulating private sales. Probability-based online survey. United States, 2015. 1613 adult gun owners. Current gun owners were asked where and when they acquired their last firearm; if they purchased the firearm; and whether, as part of that acquisition, they had a background check (or were asked to show a firearm license or permit). 22% (95% CI, 16% to 27%) of gun owners who reported obtaining their most recent firearm within the previous 2 years reported doing so without a background check. For firearms purchased privately within the previous 2 years (that is, other than from a store or pawnshop, including sales between individuals in person, online, or at gun shows), 50% (CI, 35% to 65%) were obtained without a background check. This percentage was 26% (CI, 5% to 47%) for owners residing in states regulating private firearm sales and 57% (CI, 40% to 75%) for those living in states without regulations on private firearm sales. Potential inaccuracies due to recall and social desirability bias. 22% of current U.S. gun owners who acquired a firearm within the past 2 years did so without a background check. Although this represents a smaller proportion of gun owners obtaining firearms without background checks than in the past, millions of U.S. adults continue to acquire guns without background checks, especially in states that do not regulate private firearm sales. Fund for a Safer Future and the Joyce Foundation.

Film Vetoes for Alpha Background Rejection in Bolometer Detectors

NASA Astrophysics Data System (ADS)

Deporzio, Nicholas; Bucci, Carlo; Canonica, Lucia; Divacri, Marialaura; Cuore Collaboration; Absurd Team

2015-04-01

This study characterizes the effectiveness of encasing bolometer detectors in scintillator, metal ionization, and more exotic films to veto alpha radiation background. Bolometers are highly susceptible to alpha background and a successful veto should boost the statistical strength, speed, and signal-background ratio of bolometer particle searches. Plastic scintillator films are cooled to bolometer temperatures and bombarded with 1.4 MeV to 6.0 MeV alpha particles representative of detector conditions. Photomultipliers detect the keV range scintillation light and produce a veto signal. Also, layered films of a primary metal, dielectric, and secondary metal, such as gold-polyethylene-gold films, are cooled to milli-kelvin temperatures and biased with 0.1V to 100V to produce a current signal when incident 1.4 MeV to 6.0 MeV alpha particles ionize conduction paths through the film. Veto signals are characterized by their affect on bolometer detection of 865 keV target signals. Similar methods are applied to more exotic films. Early results show scintillator films raise target signal count rate and suppress counts above target energy by at least a factor of 10. This indicates scintillation vetoes are effective and that metal ionization and other films under study will also be effective.

Computer Software & Intellectual Property. Background Paper.

ERIC Educational Resources Information Center

Congress of the U.S., Washington, DC. Office of Technology Assessment.

This background paper reviews copyright, patent, and trade secret protections as these issues are related to computer software. Topics discussed include current issues regarding legal protection for computer software including the necessity for defining intellectual property, determining what should or should not be protected, commerical piracy,…

The current state-of-the-art of spinal cord imaging: Methods

PubMed Central

Stroman, P.W.; Wheeler-Kingshott, C.; Bacon, M.; Schwab, J.M.; Bosma, R.; Brooks, J.; Cadotte, D.; Carlstedt, T.; Ciccarelli, O.; Cohen-Adad, J.; Curt, A.; Evangelou, N.; Fehlings, M.G.; Filippi, M.; Kelley, B.J.; Kollias, S.; Mackay, A.; Porro, C.A.; Smith, S.; Strittmatter, S.M.; Summers, P.; Tracey, I.

2015-01-01

A first-ever spinal cord imaging meeting was sponsored by the International Spinal Research Trust and the Wings for Life Foundation with the aim of identifying the current state-of-the-art of spinal cord imaging, the current greatest challenges, and greatest needs for future development. This meeting was attended by a small group of invited experts spanning all aspects of spinal cord imaging from basic research to clinical practice. The greatest current challenges for spinal cord imaging were identified as arising from the imaging environment itself; difficult imaging environment created by the bone surrounding the spinal canal, physiological motion of the cord and adjacent tissues, and small cross-sectional dimensions of the spinal cord, exacerbated by metallic implants often present in injured patients. Challenges were also identified as a result of a lack of “critical mass” of researchers taking on the development of spinal cord imaging, affecting both the rate of progress in the field, and the demand for equipment and software to manufacturers to produce the necessary tools. Here we define the current state-of-the-art of spinal cord imaging, discuss the underlying theory and challenges, and present the evidence for the current and potential power of these methods. In two review papers (part I and part II), we propose that the challenges can be overcome with advances in methods, improving availability and effectiveness of methods, and linking existing researchers to create the necessary scientific and clinical network to advance the rate of progress and impact of the research. PMID:23685159

The ELP through Time: Background Motivation, Growing Experience, Current Beliefs

ERIC Educational Resources Information Center

Argondizzo, Carmen; Sasso, Maria I.

2016-01-01

This article offers an overview of research strategies currently in use at the Language Centre of the University of Calabria and aimed at observing university students' learning habits when they are asked to use the European Language Portfolio during language courses. We present evidence of how experimental groups of students belonging to…

Current Economic Issues in Employee Benefits. Background Paper No. 39.

ERIC Educational Resources Information Center

Woodbury, Stephen A.

A multitude of public policy issues currently surround the tax treatment of employee benefits, particularly since the tax-favored status of employer contributions to pensions and health insurance has been blamed for a shrinking tax base that has exacerbated the federal budget deficit, an inefficient and bloated health-care sector, overinsurance by…

A Comparison of Alternating Current and Direct Current Electrospray Ionization for Mass Spectrometry

PubMed Central

Sarver, Scott A.; Gartner, Carlos A.; Chetwani, Nishant; Go, David B.; Dovichi, Norman J.

2014-01-01

A series of studies comparing the performance of alternating current electrospray ionization (AC ESI) mass spectrometry (MS) and direct current electrospray ionization (DC ESI) MS has been conducted, exploring the absolute signal intensity and signal-to-background ratios produced by both methods using caffeine and a model peptide as targets. Because the high-voltage AC signal was more susceptible to generating gas discharges, the operating voltage range of AC ESI was significantly smaller than that for DC ESI, such that the absolute signal intensities produced by DC ESI at peak voltages were 1 - 2 orders of magnitude greater than those for AC ESI. Using an electronegative nebulizing gas, sulfur hexafluoride (SF6), instead of nitrogen (N2) increased the operating range of AC ESI by ~50%, but did not appreciably improve signal intensities. While DC ESI generated far greater signal intensities, both ionization methods produced comparable signal-to-background noise, with AC ESI spectra appearing qualitatively cleaner. A quantitative calibration analysis was performed for two analytes, caffeine and the peptide MRFA. AC ESI utilizing SF6 outperforms all other techniques for the detection of MRFA, producing chromatographic limits of detection nearly one order of magnitude lower than that of DC ESI utilizing N2, and one half that of DC ESI utilizing SF6. However, DC ESI outperforms AC ESI for the analysis of caffeine, indicating improvements in spectral quality may benefit certain compounds, or classes of compounds, on an individual basis. PMID:24464359

Mapping gravitational-wave backgrounds using methods from CMB analysis: Application to pulsar timing arrays

NASA Astrophysics Data System (ADS)

Gair, Jonathan; Romano, Joseph D.; Taylor, Stephen; Mingarelli, Chiara M. F.

2014-10-01

We describe an alternative approach to the analysis of gravitational-wave backgrounds, based on the formalism used to characterize the polarization of the cosmic microwave background. In contrast to standard analyses, this approach makes no assumptions about the nature of the background and so has the potential to reveal much more about the physical processes that generated it. An arbitrary background can be decomposed into modes whose angular dependence on the sky is given by gradients and curls of spherical harmonics. We derive the pulsar timing overlap reduction functions for the individual modes, which are given by simple combinations of spherical harmonics evaluated at the pulsar locations. We show how these can be used to recover the components of an arbitrary background, giving explicit results for both isotropic and anisotropic uncorrelated backgrounds. We also find that the response of a pulsar timing array to curl modes is identically zero, so half of the gravitational-wave sky will never be observed using pulsar timing, no matter how many pulsars are included in the array. An isotropic, unpolarized and uncorrelated background can be accurately represented using only three modes, and so a search of this type will be only slightly more complicated than the standard cross-correlation search using the Hellings and Downs overlap reduction function. However, by measuring the components of individual modes of the background and checking for consistency with isotropy, this approach has the potential to reveal much more information. Each individual mode on its own describes a background that is correlated between different points on the sky. A measurement of the components that indicates the presence of correlations in the background on large angular scales would suggest startling new physics.

Method and apparatus for reducing solvent luminescence background emissions

DOEpatents

Affleck, Rhett L.; Ambrose, W. Patrick; Demas, James N.; Goodwin, Peter M.; Johnson, Mitchell E.; Keller, Richard A.; Petty, Jeffrey T.; Schecker, Jay A.; Wu, Ming

1998-01-01

The detectability of luminescent molecules in solution is enhanced by reducing the background luminescence due to impurity species also present in the solution. A light source that illuminates the solution acts to photolyze the impurities so that the impurities do not luminesce in the fluorescence band of the molecule of interest. Molecules of interest may be carried through the photolysis region in the solution or may be introduced into the solution after the photolysis region.

Introducing 3D U-statistic method for separating anomaly from background in exploration geochemical data with associated software development

NASA Astrophysics Data System (ADS)

Ghannadpour, Seyyed Saeed; Hezarkhani, Ardeshir

2016-03-01

The U-statistic method is one of the most important structural methods to separate the anomaly from the background. It considers the location of samples and carries out the statistical analysis of the data without judging from a geochemical point of view and tries to separate subpopulations and determine anomalous areas. In the present study, to use U-statistic method in three-dimensional (3D) condition, U-statistic is applied on the grade of two ideal test examples, by considering sample Z values (elevation). So far, this is the first time that this method has been applied on a 3D condition. To evaluate the performance of 3D U-statistic method and in order to compare U-statistic with one non-structural method, the method of threshold assessment based on median and standard deviation (MSD method) is applied on the two example tests. Results show that the samples indicated by U-statistic method as anomalous are more regular and involve less dispersion than those indicated by the MSD method. So that, according to the location of anomalous samples, denser areas of them can be determined as promising zones. Moreover, results show that at a threshold of U = 0, the total error of misclassification for U-statistic method is much smaller than the total error of criteria of bar {x}+n× s. Finally, 3D model of two test examples for separating anomaly from background using 3D U-statistic method is provided. The source code for a software program, which was developed in the MATLAB programming language in order to perform the calculations of the 3D U-spatial statistic method, is additionally provided. This software is compatible with all the geochemical varieties and can be used in similar exploration projects.

GafChromic EBT film dosimetry with flatbed CCD scanner: a novel background correction method and full dose uncertainty analysis.

PubMed

Saur, Sigrun; Frengen, Jomar

2008-07-01

Film dosimetry using radiochromic EBT film in combination with a flatbed charge coupled device scanner is a useful method both for two-dimensional verification of intensity-modulated radiation treatment plans and for general quality assurance of treatment planning systems and linear accelerators. Unfortunately, the response over the scanner area is nonuniform, and when not corrected for, this results in a systematic error in the measured dose which is both dose and position dependent. In this study a novel method for background correction is presented. The method is based on the subtraction of a correction matrix, a matrix that is based on scans of films that are irradiated to nine dose levels in the range 0.08-2.93 Gy. Because the response of the film is dependent on the film's orientation with respect to the scanner, correction matrices for both landscape oriented and portrait oriented scans were made. In addition to the background correction method, a full dose uncertainty analysis of the film dosimetry procedure was performed. This analysis takes into account the fit uncertainty of the calibration curve, the variation in response for different film sheets, the nonuniformity after background correction, and the noise in the scanned films. The film analysis was performed for film pieces of size 16 x 16 cm, all with the same lot number, and all irradiations were done perpendicular onto the films. The results show that the 2-sigma dose uncertainty at 2 Gy is about 5% and 3.5% for landscape and portrait scans, respectively. The uncertainty gradually increases as the dose decreases, but at 1 Gy the 2-sigma dose uncertainty is still as good as 6% and 4% for landscape and portrait scans, respectively. The study shows that film dosimetry using GafChromic EBT film, an Epson Expression 1680 Professional scanner and a dedicated background correction technique gives precise and accurate results. For the purpose of dosimetric verification, the calculated dose distribution

The International College of Neuropsychopharmacology (CINP) Treatment Guidelines for Bipolar Disorder in Adults (CINP-BD-2017), Part 1: Background and Methods of the Development of Guidelines

PubMed Central

Young, Allan; Yatham, Lakshmi; Grunze, Heinz; Vieta, Eduard; Blier, Pierre; Moeller, Hans Jurgen; Kasper, Siegfried

2017-01-01

Abstract Background: This paper includes a short description of the important clinical aspects of Bipolar Disorder with emphasis on issues that are important for the therapeutic considerations, including mixed and psychotic features, predominant polarity, and rapid cycling as well as comorbidity. Methods: The workgroup performed a review and critical analysis of the literature concerning grading methods and methods for the development of guidelines. Results: The workgroup arrived at a consensus to base the development of the guideline on randomized controlled trials and related meta-analyses alone in order to follow a strict evidence-based approach. A critical analysis of the existing methods for the grading of treatment options was followed by the development of a new grading method to arrive at efficacy and recommendation levels after the analysis of 32 distinct scenarios of available data for a given treatment option. Conclusion: The current paper reports details on the design, method, and process for the development of CINP guidelines for the treatment of Bipolar Disorder. The rationale and the method with which all data and opinions are combined in order to produce an evidence-based operationalized but also user-friendly guideline and a specific algorithm are described in detail in this paper. PMID:27815414

Method and apparatus for reducing solvent luminescence background emissions

DOEpatents

Affleck, R.L.; Ambrose, W.P.; Demas, J.N.; Goodwin, P.M.; Johnson, M.E.; Keller, R.A.; Petty, J.T.; Schecker, J.A.; Wu, M.

1998-10-27

The detectability of luminescent molecules in solution is enhanced by reducing the background luminescence due to impurity species also present in the solution. A light source that illuminates the solution acts to photolyze the impurities so that the impurities do not luminesce in the fluorescence band of the molecule of interest. Molecules of interest may be carried through the photolysis region in the solution or may be introduced into the solution after the photolysis region. 6 figs.

Systems and methods for commutating inductor current using a matrix converter

DOEpatents

Ransom, Ray M; Kajouke, Lateef A; Perisic, Milun

2012-10-16

Systems and methods are provided for delivering current using a matrix converter in a vehicle. An electrical system comprises an AC interface, a first conversion module coupled to the AC interface, an inductive element coupled between the AC interface and the first conversion module, and a control module coupled to the first conversion module. The control module is configured to operate the first conversion module in a bidirectional operating mode to commutate current bidirectionally. When a magnitude of the current through the inductive element is greater than a first threshold value, the control module operates the conversion module in a unidirectional operating mode, wherein current is commutated unidirectionally.

Physiologic correlates to background noise acceptance

NASA Astrophysics Data System (ADS)

Tampas, Joanna; Harkrider, Ashley; Nabelek, Anna

2004-05-01

Acceptance of background noise can be evaluated by having listeners indicate the highest background noise level (BNL) they are willing to accept while following the words of a story presented at their most comfortable listening level (MCL). The difference between the selected MCL and BNL is termed the acceptable noise level (ANL). One of the consistent findings in previous studies of ANL is large intersubject variability in acceptance of background noise. This variability is not related to age, gender, hearing sensitivity, personality, type of background noise, or speech perception in noise performance. The purpose of the current experiment was to determine if individual differences in physiological activity measured from the peripheral and central auditory systems of young female adults with normal hearing can account for the variability observed in ANL. Correlations between ANL and various physiological responses, including spontaneous, click-evoked, and distortion-product otoacoustic emissions, auditory brainstem and middle latency evoked potentials, and electroencephalography will be presented. Results may increase understanding of the regions of the auditory system that contribute to individual noise acceptance.

Current and Prospective Methods for Plant Disease Detection

PubMed Central

Fang, Yi; Ramasamy, Ramaraja P.

2015-01-01

Food losses due to crop infections from pathogens such as bacteria, viruses and fungi are persistent issues in agriculture for centuries across the globe. In order to minimize the disease induced damage in crops during growth, harvest and postharvest processing, as well as to maximize productivity and ensure agricultural sustainability, advanced disease detection and prevention in crops are imperative. This paper reviews the direct and indirect disease identification methods currently used in agriculture. Laboratory-based techniques such as polymerase chain reaction (PCR), immunofluorescence (IF), fluorescence in-situ hybridization (FISH), enzyme-linked immunosorbent assay (ELISA), flow cytometry (FCM) and gas chromatography-mass spectrometry (GC-MS) are some of the direct detection methods. Indirect methods include thermography, fluorescence imaging and hyperspectral techniques. Finally, the review also provides a comprehensive overview of biosensors based on highly selective bio-recognition elements such as enzyme, antibody, DNA/RNA and bacteriophage as a new tool for the early identification of crop diseases. PMID:26287253

Background Model for the Majorana Demonstrator

NASA Astrophysics Data System (ADS)

Cuesta, C.; Abgrall, N.; Aguayo, E.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Byram, D.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Combs, D. C.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Elliott, S. R.; Fast, J. E.; Finnerty, P.; Fraenkle, F. M.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guiseppe, V. E.; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Keeter, K. J.; Kidd, M. F.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Leviner, L. E.; Loach, J. C.; MacMullin, J.; MacMullin, S.; Martin, R. D.; Meijer, S.; Mertens, S.; Nomachi, M.; Orrell, J. L.; O'Shaughnessy, C.; Overman, N. R.; Phillips, D. G.; Poon, A. W. P.; Pushkin, K.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Ronquest, M. C.; Schubert, A. G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Snyder, N.; Suriano, A. M.; Thompson, J.; Timkin, V.; Tornow, W.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Young, A. R.; Yu, C.-H.; Yumatov, V.

The Majorana Collaboration is constructing a system containing 40 kg of HPGe detectors to demonstrate the feasibility and potential of a future tonne-scale experiment capable of probing the neutrino mass scale in the inverted-hierarchy region. To realize this, a major goal of the Majorana Demonstrator is to demonstrate a path forward to achieving a background rate at or below 1 cnt/(ROI-t-y) in the 4 keV region of interest around the Q-value at 2039 keV. This goal is pursued through a combination of a significant reduction of radioactive impurities in construction materials with analytical methods for background rejection, for example using powerful pulse shape analysis techniques profiting from the p-type point contact HPGe detectors technology. The effectiveness of these methods is assessed using simulations of the different background components whose purity levels are constrained from radioassay measurements.

Background model for the Majorana Demonstrator

DOE PAGES

Cuesta, C.; Abgrall, N.; Aguayo, E.; ...

2015-01-01

The Majorana Collaboration is constructing a system containing 40 kg of HPGe detectors to demonstrate the feasibility and potential of a future tonne-scale experiment capable of probing the neutrino mass scale in the inverted-hierarchy region. To realize this, a major goal of the Majorana Demonstrator is to demonstrate a path forward to achieving a background rate at or below 1 cnt/(ROI-t-y) in the 4 keV region of interest around the Q-value at 2039 keV. This goal is pursued through a combination of a significant reduction of radioactive impurities in construction materials with analytical methods for background rejection, for example usingmore » powerful pulse shape analysis techniques profiting from the p-type point contact HPGe detectors technology. The effectiveness of these methods is assessed using simulations of the different background components whose purity levels are constrained from radioassay measurements.« less

75 FR 49930 - Stakeholder Meeting Regarding Re-Evaluation of Currently Approved Total Coliform Analytical Methods

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-16

... Currently Approved Total Coliform Analytical Methods AGENCY: Environmental Protection Agency (EPA). ACTION... of currently approved Total Coliform Rule (TCR) analytical methods. At these meetings, stakeholders will be given an opportunity to discuss potential elements of a method re-evaluation study, such as...

Radon-related Backgrounds in the LUX Dark Matter Search

NASA Astrophysics Data System (ADS)

Bradley, A.; Akerib, D. S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Bernard, E.; Bernstein, A.; Byram, D.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Chapman, J. J.; Chiller, A. A.; Chiller, C.; Coffey, T.; Currie, A.; de Viveiros, L.; Dobi, A.; Dobson, J.; Druszkiewicz, E.; Edwards, B.; Faham, C. H.; Fiorucci, S.; Flores, C.; Gaitskell, R. J.; Gehman, V. M.; Ghag, C.; Gibson, K. R.; Gilchriese, M. G. D.; Hall, C.; Hertel, S. A.; Horn, M.; Huang, D. Q.; Ihm, M.; Jacobsen, R. G.; Kazkaz, K.; Knoche, R.; Larsen, N. A.; Lee, C.; Lindote, A.; Lopes, M. I.; Malling, D. C.; Mannino, R.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H.; Neves, F.; Ott, R. A.; Pangilinan, M.; Parker, P. D.; Pease, E. K.; Pech, K.; Phelps, P.; Reichhart, L.; Shutt, T.; Silva, C.; Solovov, V. N.; Sorensen, P.; O'Sullivan, K.; Sumner, T. J.; Szydagis, M.; Taylor, D.; Tennyson, B.; Tiedt, D. R.; Tripathi, M.; Uvarov, S.; Verbus, J. R.; Walsh, N.; Webb, R.; White, J. T.; Witherell, M. S.; Wolfs, F. L. H.; Woods, M.; Zhang, C.

The LUX detector is currently in operation at the Davis Campus at the 4850' level of the Sanford Underground Research Facility (SURF) in Lead, SD to directly search for WIMP dark matter. Knowing the type and rate of backgrounds is critical in a rare, low energy event search, and LUX was designed, constructed, and deployed to mitigate backgrounds, both internal and external. An important internal background are decays of radon and its daughters. These consist of alpha decays, which are easily tagged and are a tracer of certain backgrounds, and beta decays, some of which are not as readily tagged and present a background for the WIMP search. We report on studies of alpha decay and discuss implications for the WIMP search.

Current matrix element in HAL QCD's wavefunction-equivalent potential method

NASA Astrophysics Data System (ADS)

Watanabe, Kai; Ishii, Noriyoshi

2018-04-01

We give a formula to calculate a matrix element of a conserved current in the effective quantum mechanics defined by the wavefunction-equivalent potentials proposed by the HAL QCD collaboration. As a first step, a non-relativistic field theory with two-channel coupling is considered as the original theory, with which a wavefunction-equivalent HAL QCD potential is obtained in a closed analytic form. The external field method is used to derive the formula by demanding that the result should agree with the original theory. With this formula, the matrix element is obtained by sandwiching the effective current operator between the left and right eigenfunctions of the effective Hamiltonian associated with the HAL QCD potential. In addition to the naive one-body current, the effective current operator contains an additional two-body term emerging from the degrees of freedom which has been integrated out.

Current status of antifungal susceptibility testing methods.

PubMed

Arikan, Sevtap

2007-11-01

Antifungal susceptibility testing is a very dynamic field of medical mycology. Standardization of in vitro susceptibility tests by the Clinical and Laboratory Standards Institute (CLSI) and the European Committee for Antimicrobial Susceptibility Testing (EUCAST), and current availability of reference methods constituted the major remarkable steps in the field. Based on the established minimum inhibitory concentration (MIC) breakpoints, it is now possible to determine the susceptibilities of Candida strains to fluconazole, itraconazole, voriconazole, and flucytosine. Moreover, utility of fluconazole antifungal susceptibility tests as an adjunct in optimizing treatment of candidiasis has now been validated. While the MIC breakpoints and clinical significance of susceptibility testing for the remaining fungi and antifungal drugs remain yet unclear, modifications of the available methods as well as other methodologies are being intensively studied to overcome the present drawbacks and limitations. Among the other methods under investigation are Etest, colorimetric microdilution, agar dilution, determination of fungicidal activity, flow cytometry, and ergosterol quantitation. Etest offers the advantage of practical application and favorable agreement rates with the reference methods that are frequently above acceptable limits. However, MIC breakpoints for Etest remain to be evaluated and established. Development of commercially available, standardized colorimetric panels that are based on CLSI method parameters has added more to the antifungal susceptibility testing armamentarium. Flow cytometry, on the other hand, appears to offer rapid susceptibility testing but requires specified equipment and further evaluation for reproducibility and standardization. Ergosterol quantitation is another novel approach, which appears potentially beneficial particularly in discrimination of azole-resistant isolates from heavy trailers. The method is yet investigational and requires to

Automatic background updating for video-based vehicle detection

NASA Astrophysics Data System (ADS)

Hu, Chunhai; Li, Dongmei; Liu, Jichuan

2008-03-01

Video-based vehicle detection is one of the most valuable techniques for the Intelligent Transportation System (ITS). The widely used video-based vehicle detection technique is the background subtraction method. The key problem of this method is how to subtract and update the background effectively. In this paper an efficient background updating scheme based on Zone-Distribution for vehicle detection is proposed to resolve the problems caused by sudden camera perturbation, sudden or gradual illumination change and the sleeping person problem. The proposed scheme is robust and fast enough to satisfy the real-time constraints of vehicle detection.

Stacked Multilayer Self-Organizing Map for Background Modeling.

PubMed

Zhao, Zhenjie; Zhang, Xuebo; Fang, Yongchun

2015-09-01

In this paper, a new background modeling method called stacked multilayer self-organizing map background model (SMSOM-BM) is proposed, which presents several merits such as strong representative ability for complex scenarios, easy to use, and so on. In order to enhance the representative ability of the background model and make the parameters learned automatically, the recently developed idea of representative learning (or deep learning) is elegantly employed to extend the existing single-layer self-organizing map background model to a multilayer one (namely, the proposed SMSOM-BM). As a consequence, the SMSOM-BM gains several merits including strong representative ability to learn background model of challenging scenarios, and automatic determination for most network parameters. More specifically, every pixel is modeled by a SMSOM, and spatial consistency is considered at each layer. By introducing a novel over-layer filtering process, we can train the background model layer by layer in an efficient manner. Furthermore, for real-time performance consideration, we have implemented the proposed method using NVIDIA CUDA platform. Comparative experimental results show superior performance of the proposed approach.

System and method for bearing fault detection using stator current noise cancellation

DOEpatents

Zhou, Wei; Lu, Bin; Habetler, Thomas G.; Harley, Ronald G.; Theisen, Peter J.

2010-08-17

A system and method for detecting incipient mechanical motor faults by way of current noise cancellation is disclosed. The system includes a controller configured to detect indicia of incipient mechanical motor faults. The controller further includes a processor programmed to receive a baseline set of current data from an operating motor and define a noise component in the baseline set of current data. The processor is also programmed to repeatedly receive real-time operating current data from the operating motor and remove the noise component from the operating current data in real-time to isolate any fault components present in the operating current data. The processor is then programmed to generate a fault index for the operating current data based on any isolated fault components.

Method and apparatus for producing co-current fluid contact

DOEpatents

Trutna, William R.

1997-01-01

An improved packing system and method are disclosed wherein a packing section includes a liquid distributor and a separator placed above the distributor so that gas rising through the liquid distributor contacts liquid in the distributor, forming a gas-liquid combination which rises in co-current flow to the separator. Liquid is collected in the separator, from which gas rises.

Method and apparatus for producing co-current fluid contact

DOEpatents

Trutna, W.R.

1997-12-09

An improved packing system and method are disclosed wherein a packing section includes a liquid distributor and a separator placed above the distributor so that gas rising through the liquid distributor contacts liquid in the distributor, forming a gas-liquid combination which rises in co-current flow to the separator. Liquid is collected in the separator, from which gas rises. 13 figs.

A pre-heating method based on sinusoidal alternating current for lithium-ion battery

NASA Astrophysics Data System (ADS)

Fan, Wentao; Sun, Fengchun; Guo, Shanshan

2018-04-01

In this paper, a method of low temperature pre-heating of sinusoidal alternating current (SAC) is proposed. Generally, the lower the frequency of the AC current, the higher the heat generation rate. Yet at low frequency, there is a risk of lithium-ion deposition during the half cycle of charging. This study develops a temperature-adaptive, deposition-free AC pre-heating method. a equivalent electric circuit(EEC) model is established to predict the heat generation rate and temperature status, whose parameters are calibrated from the EIS impedance measurements. The effects of current frequency and amplitude on the heating effect are investigated respectively. A multistep temperature-adaptive amplitude strategy is proposed and the cell can be heated from -20°C to 5°C within 509s at 100Hz frequency with this method.

A new method for electric impedance imaging using an eddy current with a tetrapolar circuit.

PubMed

Ahsan-Ul-Ambia; Toda, Shogo; Takemae, Tadashi; Kosugi, Yukio; Hongo, Minoru

2009-02-01

A new contactless technique for electrical impedance imaging, using an eddy current managed along with the tetrapolar circuit method, is proposed. The eddy current produced by a magnetic field is superimposed on a constant current that is normally used in the tetrapolar circuit method, and thus is used to control the current distribution in the body. By changing the current distribution, a set of voltage differences is measured with a pair of electrodes. This set of voltage differences is used in the image reconstruction of the resistivity distribution. The least square error minimization method is used in the reconstruction algorithm. The principle of this method is explained theoretically. A backprojection algorithm was used to get 2-D images. Based on this principle, a measurement system was developed and model experiments were conducted with a saline-filled phantom. The estimated shape of each model in the reconstructed image was similar to that of the corresponding model. From the results of these experiments, it is confirmed that the proposed method is applicable to the realization of electrical conductivity imaging.

Over-current carrying characteristics of rectangular-shaped YBCO thin films prepared by MOD method

NASA Astrophysics Data System (ADS)

Hotta, N.; Yokomizu, Y.; Iioka, D.; Matsumura, T.; Kumagai, T.; Yamasaki, H.; Shibuya, M.; Nitta, T.

2008-02-01

A fault current limiter (FCL) may be manufactured at competitive qualities and prices by using rectangular-shaped YBCO films which are prepared by metal-organic deposition (MOD) method, because the MOD method can produce large size elements with a low-cost and non-vacuum technique. Prior to constructing a superconducting FCL (SFCL), AC over-current carrying experiments were conducted for 120 mm long elements where YBCO thin film of about 200 nm in thickness was coated on sapphire substrate with cerium oxide (CeO2) interlayer. In the experiments, only single cycle of the ac damping current of 50 Hz was applied to the pure YBCO element without protective metal coating or parallel resistor and the magnitude of the current was increased step by step until the breakdown phenomena occurred in the element. In each experiment, current waveforms flowing through the YBCO element and voltage waveform across the element were measured to get the voltage-current characteristics. The allowable over-current and generated voltage were successfully estimated for the pure YBCO films. It can be pointed out that the lower n-value trends to bring about the higher allowable over-current and the higher withstand voltage more than tens of volts. The YBCO film having higher n-value is sensitive to the over-current. Thus, some protective methods such as a metal coating should be employed for applying to the fault current limiter.

Automatic vehicle counting using background subtraction method on gray scale images and morphology operation

NASA Astrophysics Data System (ADS)

Adi, K.; Widodo, A. P.; Widodo, C. E.; Pamungkas, A.; Putranto, A. B.

2018-05-01

Traffic monitoring on road needs to be done, the counting of the number of vehicles passing the road is necessary. It is more emphasized for highway transportation management in order to prevent efforts. Therefore, it is necessary to develop a system that is able to counting the number of vehicles automatically. Video processing method is able to counting the number of vehicles automatically. This research has development a system of vehicle counting on toll road. This system includes processes of video acquisition, frame extraction, and image processing for each frame. Video acquisition is conducted in the morning, at noon, in the afternoon, and in the evening. This system employs of background subtraction and morphology methods on gray scale images for vehicle counting. The best vehicle counting results were obtained in the morning with a counting accuracy of 86.36 %, whereas the lowest accuracy was in the evening, at 21.43 %. Differences in morning and evening results are caused by different illumination in the morning and evening. This will cause the values in the image pixels to be different.

Level crossing analysis of cosmic microwave background radiation: a method for detecting cosmic strings

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

Movahed, M. Sadegh; Khosravi, Shahram, E-mail: m.s.movahed@ipm.ir, E-mail: khosravi@ipm.ir

2011-03-01

In this paper we study the footprint of cosmic string as the topological defects in the very early universe on the cosmic microwave background radiation. We develop the method of level crossing analysis in the context of the well-known Kaiser-Stebbins phenomenon for exploring the signature of cosmic strings. We simulate a Gaussian map by using the best fit parameter given by WMAP-7 and then superimpose cosmic strings effects on it as an incoherent and active fluctuations. In order to investigate the capability of our method to detect the cosmic strings for the various values of tension, Gμ, a simulated puremore » Gaussian map is compared with that of including cosmic strings. Based on the level crossing analysis, the superimposed cosmic string with Gμ∼>4 × 10{sup −9} in the simulated map without instrumental noise and the resolution R = 1' could be detected. In the presence of anticipated instrumental noise the lower bound increases just up to Gμ∼>5.8 × 10{sup −9}.« less

Metal-as-insulation variant of no-insulation HTS winding technique: pancake tests under high background magnetic field and high current at 4.2 K

NASA Astrophysics Data System (ADS)

Lécrevisse, T.; Badel, A.; Benkel, T.; Chaud, X.; Fazilleau, P.; Tixador, P.

2018-05-01

In the framework of a project aiming at fabricating a 10 T high temperature superconducting (HTS) insert to operate in a 20 T background field, we are investigating the behavior of pancakes consisting of a REBCO HTS tape co-wound with a stainless steel tape (metal-as-insulation (MI) coil). The MI winding is inducing a significant turn-to-turn electrical resistance which helps to reduce the charging time delay. Despite this resistance, the self-protection feature of no-insulation coils is still enabled, thanks to the voltage limit of the power supply. We have built a single pancake coil representative of the pancake that will be used in the insert and performed tests under very high background magnetic field. Our coil experienced over 100 heater induced quenches without a measureable increase of its internal resistance. We have gathered stability and quench behavior data for magnetic fields and engineering current densities (je ) in the range of 0–17 T and 0–635 A mm‑2 respectively. We also present our very first experiments on the insert/outsert interaction in the case of a resistive magnet fault. We show that if self-protection of the MI winding is really effective in the case of a MI coil quench, a major issue comes from the outsert fault which induces a huge current inside the MI coil.

Radon-related backgrounds in the LUX dark matter search

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

Bradley, A.; Akerib, D. S.; Araújo, H. M.

The LUX detector is currently in operation at the Davis Campus at the 4850’ level of the Sanford Underground Research Facility (SURF) in Lead, SD to directly search for WIMP dark matter. Knowing the type and rate of backgrounds is critical in a rare, low energy event search, and LUX was designed, constructed, and deployed to mitigate backgrounds, both internal and external. An important internal background are decays of radon and its daughters. These consist of alpha decays, which are easily tagged and are a tracer of certain backgrounds, and beta decays, some of which are not as readily taggedmore » and present a background for the WIMP search. We report on studies of alpha decay and discuss implications for the WIMP search.« less

Radon-related backgrounds in the LUX dark matter search

DOE PAGES

Bradley, A.; Akerib, D. S.; Araújo, H. M.; ...

2015-01-01

The LUX detector is currently in operation at the Davis Campus at the 4850’ level of the Sanford Underground Research Facility (SURF) in Lead, SD to directly search for WIMP dark matter. Knowing the type and rate of backgrounds is critical in a rare, low energy event search, and LUX was designed, constructed, and deployed to mitigate backgrounds, both internal and external. An important internal background are decays of radon and its daughters. These consist of alpha decays, which are easily tagged and are a tracer of certain backgrounds, and beta decays, some of which are not as readily taggedmore » and present a background for the WIMP search. We report on studies of alpha decay and discuss implications for the WIMP search.« less

Analysis of Electric Vehicle DC High Current Conversion Technology

NASA Astrophysics Data System (ADS)

Yang, Jing; Bai, Jing-fen; Lin, Fan-tao; Lu, Da

2017-05-01

Based on the background of electric vehicles, it is elaborated the necessity about electric energy accurate metering of electric vehicle power batteries, and it is analyzed about the charging and discharging characteristics of power batteries. It is needed a DC large current converter to realize accurate calibration of power batteries electric energy metering. Several kinds of measuring methods are analyzed based on shunts and magnetic induction principle in detail. It is put forward power batteries charge and discharge calibration system principle, and it is simulated and analyzed ripple waves containing rate and harmonic waves containing rate of power batteries AC side and DC side. It is put forward suitable DC large current measurement methods of power batteries by comparing different measurement principles and it is looked forward the DC large current measurement techniques.

Method and apparatus for correcting eddy current signal voltage for temperature effects

DOEpatents

Kustra, Thomas A.; Caffarel, Alfred J.

1990-01-01

An apparatus and method for measuring physical characteristics of an electrically conductive material by the use of eddy-current techniques and compensating measurement errors caused by changes in temperature includes a switching arrangement connected between primary and reference coils of an eddy-current probe which allows the probe to be selectively connected between an eddy current output oscilloscope and a digital ohm-meter for measuring the resistances of the primary and reference coils substantially at the time of eddy current measurement. In this way, changes in resistance due to temperature effects can be completely taken into account in determining the true error in the eddy current measurement. The true error can consequently be converted into an equivalent eddy current measurement correction.

PE Metrics: Background, Testing Theory, and Methods

ERIC Educational Resources Information Center

Zhu, Weimo; Rink, Judy; Placek, Judith H.; Graber, Kim C.; Fox, Connie; Fisette, Jennifer L.; Dyson, Ben; Park, Youngsik; Avery, Marybell; Franck, Marian; Raynes, De

2011-01-01

New testing theories, concepts, and psychometric methods (e.g., item response theory, test equating, and item bank) developed during the past several decades have many advantages over previous theories and methods. In spite of their introduction to the field, they have not been fully accepted by physical educators. Further, the manner in which…

Background-Limited Infrared-Submillimeter Spectroscopy (BLISS)

NASA Technical Reports Server (NTRS)

Bradford, Charles Matt

2004-01-01

The bulk of the cosmic far-infrared background light will soon be resolved into its individual sources with Spitzer, Astro-F, Herschel, and submm/mm ground-based cameras. The sources will be dusty galaxies at z approximately equal to 1-4. Their physical conditions and processes in these galaxies are directly probed with moderate-resolution spectroscopy from 20 micrometers to 1 mm. Currently large cold telescopes are being combined with sensitive direct detectors, offering the potential for mid-far-IR spectroscopy at the background limit (BLISS). The capability will allow routine observations of even modest high-redshift galaxies in a variety of lines. The BLISS instrument's capabilities are described in this presentation.

Background derivation and image flattening: getimages

NASA Astrophysics Data System (ADS)

Men'shchikov, A.

2017-11-01

Modern high-resolution images obtained with space observatories display extremely strong intensity variations across images on all spatial scales. Source extraction in such images with methods based on global thresholding may bring unacceptably large numbers of spurious sources in bright areas while failing to detect sources in low-background or low-noise areas. It would be highly beneficial to subtract background and equalize the levels of small-scale fluctuations in the images before extracting sources or filaments. This paper describes getimages, a new method of background derivation and image flattening. It is based on median filtering with sliding windows that correspond to a range of spatial scales from the observational beam size up to a maximum structure width Xλ. The latter is a single free parameter of getimages that can be evaluated manually from the observed image ℐλ. The median filtering algorithm provides a background image \\tilde{Bλ} for structures of all widths below Xλ. The same median filtering procedure applied to an image of standard deviations 𝓓λ derived from a background-subtracted image \\tilde{Sλ} results in a flattening image \\tilde{Fλ}. Finally, a flattened detection image I{λD} = \\tilde{Sλ}/\\tilde{Fλ} is computed, whose standard deviations are uniform outside sources and filaments. Detecting sources in such greatly simplified images results in much cleaner extractions that are more complete and reliable. As a bonus, getimages reduces various observational and map-making artifacts and equalizes noise levels between independent tiles of mosaicked images.

System and method for motor fault detection using stator current noise cancellation

DOEpatents

Zhou, Wei; Lu, Bin; Nowak, Michael P.; Dimino, Steven A.

2010-12-07

A system and method for detecting incipient mechanical motor faults by way of current noise cancellation is disclosed. The system includes a controller configured to detect indicia of incipient mechanical motor faults. The controller further includes a processor programmed to receive a baseline set of current data from an operating motor and define a noise component in the baseline set of current data. The processor is also programmed to acquire at least on additional set of real-time operating current data from the motor during operation, redefine the noise component present in each additional set of real-time operating current data, and remove the noise component from the operating current data in real-time to isolate any fault components present in the operating current data. The processor is then programmed to generate a fault index for the operating current data based on any isolated fault components.

System and method for quench and over-current protection of superconductor

DOEpatents

Huang, Xianrui; Laskaris, Evangelos Trifon; Sivasubramaniam, Kiruba Haran; Bray, James William; Ryan, David Thomas; Fogarty, James Michael; Steinbach, Albert Eugene

2005-05-31

A system and method for protecting a superconductor. The system may comprise a current sensor operable to detect a current flowing through the superconductor. The system may comprise a coolant temperature sensor operable to detect the temperature of a cryogenic coolant used to cool the superconductor to a superconductive state. The control circuit is operable to estimate the superconductor temperature based on the current flow and the coolant temperature. The system may also be operable to compare the estimated superconductor temperature to at least one threshold temperature and to initiate a corrective action when the superconductor temperature exceeds the at least one threshold temperature.

Reducing background contributions in fluorescence fluctuation time-traces for single-molecule measurements in solution.

PubMed

Földes-Papp, Zeno; Liao, Shih-Chu Jeff; You, Tiefeng; Barbieri, Beniamino

2009-08-01

We first report on the development of new microscope means that reduce background contributions in fluorescence fluctuation methods: i) excitation shutter, ii) electronic switches, and iii) early and late time-gating. The elements allow for measuring molecules at low analyte concentrations. We first found conditions of early and late time-gating with time-correlated single-photon counting that made the fluorescence signal as bright as possible compared with the fluctuations in the background count rate in a diffraction-limited optical set-up. We measured about a 140-fold increase in the amplitude of autocorrelated fluorescence fluctuations at the lowest analyte concentration of about 15 pM, which gave a signal-to-background advantage of more than two-orders of magnitude. The results of this original article pave the way for single-molecule detection in solution and in live cells without immobilization or hydrodynamic/electrokinetic focusing at longer observation times than are currently available.

Stochastic gravitational wave background from light cosmic strings

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

DePies, Matthew R.; Hogan, Craig J.

2007-06-15

Spectra of the stochastic gravitational wave backgrounds from cosmic strings are calculated and compared with present and future experimental limits. Motivated by theoretical expectations of light cosmic strings in superstring cosmology, improvements in experimental sensitivity, and recent demonstrations of large, stable loop formation from a primordial network, this study explores a new range of string parameters with masses lighter than previously investigated. A standard 'one-scale' model for string loop formation is assumed. Background spectra are calculated numerically for dimensionless string tensions G{mu}/c{sup 2} between 10{sup -7} and 10{sup -18}, and initial loop sizes as a fraction of the Hubble radiusmore » {alpha} from 0.1 to 10{sup -6}. The spectra show a low frequency power-law tail, a broad spectral peak due to loops decaying at the present epoch (including frequencies higher than their fundamental mode, and radiation associated with cusps), and a flat (constant energy density) spectrum at high frequencies due to radiation from loops that decayed during the radiation-dominated era. The string spectrum is distinctive and unlike any other known source. The peak of the spectrum for light strings appears at high frequencies, significantly affecting predicted signals. The spectra of the cosmic string backgrounds are compared with current millisecond pulsar limits and Laser Interferometer Space Antenna (LISA) sensitivity curves. For models with large stable loops ({alpha}=0.1), current pulsar-timing limits exclude G{mu}/c{sup 2}>10{sup -9}, a much tighter limit on string tension than achievable with other techniques, and within the range of current models based on brane inflation. LISA may detect a background from strings as light as G{mu}/c{sup 2}{approx_equal}10{sup -16}, corresponding to field theory strings formed at roughly 10{sup 11} GeV.« less

Infrared images target detection based on background modeling in the discrete cosine domain

NASA Astrophysics Data System (ADS)

Ye, Han; Pei, Jihong

2018-02-01

Background modeling is the critical technology to detect the moving target for video surveillance. Most background modeling techniques are aimed at land monitoring and operated in the spatial domain. A background establishment becomes difficult when the scene is a complex fluctuating sea surface. In this paper, the background stability and separability between target are analyzed deeply in the discrete cosine transform (DCT) domain, on this basis, we propose a background modeling method. The proposed method models each frequency point as a single Gaussian model to represent background, and the target is extracted by suppressing the background coefficients. Experimental results show that our approach can establish an accurate background model for seawater, and the detection results outperform other background modeling methods in the spatial domain.

The current status of methods used by the elderly for suicides in England and Wales

PubMed Central

Shah, Ajit; Buckley, Laura

2011-01-01

Abstract: Background: Suicide rates in older people in England and Wales have declined in recent years. The challenge, therefore, is to sustain this downward trend. Better understanding of the current methods of suicide used by older people may inform strategies to sustain this decline. Methods: A study to ascertain the up to date status of methods of suicides used by older people in England and Wales was undertaken using the latest available national mortality data (suicides and open verdicts) from the Office of National Statistics for the years 2001 to 2007. Suicide in this study is measured by and includes the combination of deaths due to suicides (ICD-10 codes X60-X84) and open verdicts (ICD-10 codes Y10-Y34). The chi square test (corrected for continuity) was used to examine the differences in the methods of suicide between: (i) those under the age of 65 years and those aged 65 years and over in both sexes; (ii) males and females aged 65 years and over. Results: Hanging, strangulation and suffocation (males, 40.2%; females 20.1%), drowning and submersion (males, 8.2%; females 11.4%), and other and unspecified drugs, medicaments and biological substances (males, 8%; females, 20.4%) were the most common methods of suicide in older people. There were significant differences in the methods of suicide used by older men and women, and by older and younger people in both sexes. Suicide by unspecified means was common in both older men and women and higher in older women than older men. Unfortunately, data on the potential method of suicide is not available for these "unspecified means. Conclusions: The clear differences in the methods of suicide between older and younger people and between older men and women suggest a need to develop different strategies to reduce access to these methods of suicide for different age and sex groups. Also, potentially preventable methods of suicide may be hidden behind suicide by unspecified means. Therefore, there is a need to

Assessment of current AASHTO LRFD methods for static pile capacity analysis in Rhode Island soils.

DOT National Transportation Integrated Search

2013-07-01

This report presents an assessment of current AASHTO LRFD methods for static pile capacity analysis in Rhode : Island soils. Current static capacity methods and associated resistance factors are based on pile load test data in sands : and clays. Some...

Probabilistic BPRRC: Robust Change Detection against Illumination Changes and Background Movements

NASA Astrophysics Data System (ADS)

Yokoi, Kentaro

This paper presents Probabilistic Bi-polar Radial Reach Correlation (PrBPRRC), a change detection method that is robust against illumination changes and background movements. Most of the traditional change detection methods are robust against either illumination changes or background movements; BPRRC is one of the illumination-robust change detection methods. We introduce a probabilistic background texture model into BPRRC and add the robustness against background movements including foreground invasions such as moving cars, walking people, swaying trees, and falling snow. We show the superiority of PrBPRRC in the environment with illumination changes and background movements by using three public datasets and one private dataset: ATON Highway data, Karlsruhe traffic sequence data, PETS 2007 data, and Walking-in-a-room data.

Modeling Lost-Particle Backgrounds in PEP-II Using LPTURTLE

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

Fieguth, T.; /SLAC; Barlow, R.

2005-05-17

Background studies during the design, construction, commissioning, operation and improvement of BaBar and PEP-II have been greatly influenced by results from a program referred to as LPTURTLE (Lost Particle TURTLE) which was originally conceived for the purpose of studying gas background for SLC. This venerable program is still in use today. We describe its use, capabilities and improvements and refer to current results now being applied to BaBar.

General Aviation in Nebraska: Nebraska SATS Project Background Paper No. 1

NASA Technical Reports Server (NTRS)

Smith, Russell; Wachal, Jocelyn

2000-01-01

The Nebraska SATS project is a state-level component of NASA's Small Aircraft Transportation System (SATS). During the next several years the project will examine several different factors affecting SATS implementation in Nebraska. These include economic and taxation issues, public policy issues, airport planning processes, information dissemination strategies, and systemic change factors. This background paper profiles the general aviation system in Nebraska. It is written to provide information about the "context" within which SATS will be pursued. The primary focus is thus on describing and providing background information about the current situation. A secondary focus is on drawing general conclusions about the ability of the current system to incorporate the types of changes implied by SATS. First, some brief information on the U.S. aviation system is provided. The next two sections profile the current general aviation aircraft and pilot base. Nebraska's system of general aviation airports is then described. Within this section of the paper, information is provided on the different types of general aviation airports in Nebraska, airport activity levels and current infrastructure. The fourth major section of the background paper looks at Nebraska's local airport authorities. These special purpose local governments oversee the majority of the general aviation airports in the state. Among the items examined are total expenditures, capital expenditures and planning activities. Next, the paper provides background information on the Nebraska Department of Aeronautics (NDA) and recent Federal funding for general aviation in Nebraska. The final section presents summary conclusions.

Dissecting the Gamma-Ray Background in Search of Dark Matter

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

Cholis, Ilias; Hooper, Dan; McDermott, Samuel D.

2014-02-01

Several classes of astrophysical sources contribute to the approximately isotropic gamma-ray background measured by the Fermi Gamma-Ray Space Telescope. In this paper, we use Fermi's catalog of gamma-ray sources (along with corresponding source catalogs at infrared and radio wavelengths) to build and constrain a model for the contributions to the extragalactic gamma-ray background from astrophysical sources, including radio galaxies, star-forming galaxies, and blazars. We then combine our model with Fermi's measurement of the gamma-ray background to derive constraints on the dark matter annihilation cross section, including contributions from both extragalactic and galactic halos and subhalos. The resulting constraints are competitivemore » with the strongest current constraints from the Galactic Center and dwarf spheroidal galaxies. As Fermi continues to measure the gamma-ray emission from a greater number of astrophysical sources, it will become possible to more tightly constrain the astrophysical contributions to the extragalactic gamma-ray background. We project that with 10 years of data, Fermi's measurement of this background combined with the improved constraints on the astrophysical source contributions will yield a sensitivity to dark matter annihilations that exceeds the strongest current constraints by a factor of ~ 5 - 10.« less

Apparatus and method for measuring critical current properties of a coated conductor

DOEpatents

Mueller, Fred M [Los Alamos, NM; Haenisch, Jens [Dresden, DE

2012-07-24

The transverse critical-current uniformity in a superconducting tape was determined using a magnetic knife apparatus. A critical current I.sub.c distribution and transverse critical current density J.sub.c distribution in YBCO coated conductors was measured nondestructively with high resolution using a magnetic knife apparatus. The method utilizes the strong depression of J.sub.c in applied magnetic fields. A narrow region of low, including zero, magnetic field in a surrounding higher field is moved transversely across a sample of coated conductor. This reveals the critical current density distribution. A Fourier series inversion process was used to determine the transverse J.sub.c distribution in the sample.

Detection and sizing of cracks in structural steel using the eddy current method

DOT National Transportation Integrated Search

2000-11-01

This report summarizes research pertaining to the application of the Eddy Current method as a means of crack detection in structural steel members of highway bridges. Eddy currents are induced when an energized coil is placed near the surface of a co...

Background Model for the Majorana Demonstrator

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

Cuesta, C.; Abgrall, N.; Aguayo, Estanislao

2015-06-01

The Majorana Collaboration is constructing a prototype system containing 40 kg of HPGe detectors to demonstrate the feasibility and potential of a future tonne-scale experiment to search for neutrinoless double-beta (0v BB) decay in 76Ge. In view of the requirement that the next generation of tonne-scale Ge-based 0vBB-decay experiment be capable of probing the neutrino mass scale in the inverted-hierarchy region, a major goal of theMajorana Demonstrator is to demonstrate a path forward to achieving a background rate at or below 1 cnt/(ROI-t-y) in the 4 keV region of interest around the Q-value at 2039 keV. This goal is pursuedmore » through a combination of a significant reduction of radioactive impurities in construction materials with analytical methods for background rejection, for example using powerful pulse shape analysis techniques profiting from the p-type point contact HPGe detectors technology. The effectiveness of these methods is assessed using Geant4 simulations of the different background components whose purity levels are constrained from radioassay measurements.« less

Optimal Background Estimators in Single-Molecule FRET Microscopy.

PubMed

Preus, Søren; Hildebrandt, Lasse L; Birkedal, Victoria

2016-09-20

Single-molecule total internal reflection fluorescence (TIRF) microscopy constitutes an umbrella of powerful tools that facilitate direct observation of the biophysical properties, population heterogeneities, and interactions of single biomolecules without the need for ensemble synchronization. Due to the low signal/noise ratio in single-molecule TIRF microscopy experiments, it is important to determine the local background intensity, especially when the fluorescence intensity of the molecule is used quantitatively. Here we compare and evaluate the performance of different aperture-based background estimators used particularly in single-molecule Förster resonance energy transfer. We introduce the general concept of multiaperture signatures and use this technique to demonstrate how the choice of background can affect the measured fluorescence signal considerably. A new, to our knowledge, and simple background estimator is proposed, called the local statistical percentile (LSP). We show that the LSP background estimator performs as well as current background estimators at low molecular densities and significantly better in regions of high molecular densities. The LSP background estimator is thus suited for single-particle TIRF microscopy of dense biological samples in which the intensity itself is an observable of the technique. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Modeling background radiation in Southern Nevada

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

Haber, Daniel A.; Burnley, Pamela C.; Adcock, Christopher T.

Aerial gamma ray surveys are an important tool for national security, scientific, and industrial interests in determining locations of both anthropogenic and natural sources of radioactivity. There is a relationship between radioactivity and geology and in the past this relationship has been used to predict geology from an aerial survey. The purpose of this project is to develop a method to predict the radiologic exposure rate of the geologic materials by creating a high resolution background model. The intention is for this method to be used in an emergency response scenario where the background radiation envi-ronment is unknown. Two studymore » areas in Southern Nevada have been modeled using geologic data, images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), geochemical data, and pre-existing low resolution aerial surveys from the National Uranium Resource Evaluation (NURE) Survey. Using these data, geospatial areas that are homogenous in terms of K, U, and Th, referred to as background radiation units, are defined and the gamma ray exposure rate is predicted. The prediction is compared to data collected via detailed aerial survey by the Department of Energy's Remote Sensing Lab - Nellis, allowing for the refinement of the technique. By using geologic units to define radiation background units of exposed bedrock and ASTER visualizations to subdivide and define radiation background units within alluvium, successful models have been produced for Government Wash, north of Lake Mead, and for the western shore of Lake Mohave, east of Searchlight, NV.« less

Modeling background radiation in Southern Nevada

DOE PAGES

Haber, Daniel A.; Burnley, Pamela C.; Adcock, Christopher T.; ...

2017-02-06

Aerial gamma ray surveys are an important tool for national security, scientific, and industrial interests in determining locations of both anthropogenic and natural sources of radioactivity. There is a relationship between radioactivity and geology and in the past this relationship has been used to predict geology from an aerial survey. The purpose of this project is to develop a method to predict the radiologic exposure rate of the geologic materials by creating a high resolution background model. The intention is for this method to be used in an emergency response scenario where the background radiation envi-ronment is unknown. Two studymore » areas in Southern Nevada have been modeled using geologic data, images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), geochemical data, and pre-existing low resolution aerial surveys from the National Uranium Resource Evaluation (NURE) Survey. Using these data, geospatial areas that are homogenous in terms of K, U, and Th, referred to as background radiation units, are defined and the gamma ray exposure rate is predicted. The prediction is compared to data collected via detailed aerial survey by the Department of Energy's Remote Sensing Lab - Nellis, allowing for the refinement of the technique. By using geologic units to define radiation background units of exposed bedrock and ASTER visualizations to subdivide and define radiation background units within alluvium, successful models have been produced for Government Wash, north of Lake Mead, and for the western shore of Lake Mohave, east of Searchlight, NV.« less

Virtual reality and neuropsychology: upgrading the current tools.

PubMed

Schultheis, Maria T; Himelstein, Jessica; Rizzo, Albert A

2002-10-01

Virtual reality (VR) is an evolving technology that has been applied in various aspects of medicine, including the treatment of phobia disorders, pain distraction interventions, surgical training, and medical education. These applications have served to demonstrate the various assets offered through the use of VR. To provide a background and rationale for the application of VR to neuropsychological assessment. A brief introduction to VR technology and a review of current ongoing neuropsychological research that integrates the use of this technology. VR offers numerous assets that may enhance current neuropsychological assessment protocols and address many of the limitations faced by our traditional methods.

A new Method for Determining the Interplanetary Current-Sheet Local Orientation

NASA Astrophysics Data System (ADS)

Blanco, J. J.; Rodríguez-pacheco, J.; Sequeiros, J.

2003-03-01

In this work we have developed a new method for determining the interplanetary current sheet local parameters. The method, called `HYTARO' (from Hyperbolic Tangent Rotation), is based on a modified Harris magnetic field. This method has been applied to a pool of 57 events, all of them recorded during solar minimum conditions. The model performance has been tested by comparing both, its outputs and noise response, with these of the `classic MVM' (from Minimum Variance Method). The results suggest that, despite the fact that in many cases they behave in a similar way, there are specific crossing conditions that produce an erroneous MVM response. Moreover, our method shows a lower noise level sensitivity than that of MVM.

Numerical simulation of wave-current interaction using the SPH method

NASA Astrophysics Data System (ADS)

He, Ming; Gao, Xi-feng; Xu, Wan-hai

2018-05-01

In this paper, the smoothed particle hydrodynamics (SPH) method is used to build a numerical wave-current tank (NWCT). The wave is generated by using a piston-type wave generator and is absorbed by using a sponge layer. The uniform current field is generated by simultaneously imposing the directional velocity and hydrostatic pressure in both inflow and outflow regions set below the NWCT. Particle cyclic boundaries are also implemented for recycling the Lagrangian fluid particles. Furthermore, to shorten the time to reach a steady state, a temporary rigid-lid treatment for the water surface is proposed. It turns out to be very effective for weakening the undesired oscillatory flow at the beginning stage of the current generation. The calculated water surface elevation and horizontal-velocity profile are validated against the available experimental data. Satisfactory agreements are obtained, demonstrating the good capability of the NWCT.

Characterizing the Background Corona with SDO/AIA

NASA Technical Reports Server (NTRS)

Napier, Kate; Alexander, Caroline; Winebarger, Amy

2014-01-01

Characterizing the nature of the solar coronal background would enable scientists to more accurately determine plasma parameters, and may lead to a better understanding of the coronal heating problem. Because scientists study the 3D structure of the Sun in 2D, any line-of-sight includes both foreground and background material, and thus, the issue of background subtraction arises. By investigating the intensity values in and around an active region, using multiple wavelengths collected from the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO) over an eight-hour period, this project aims to characterize the background as smooth or structured. Different methods were employed to measure the true coronal background and create minimum intensity images. These were then investigated for the presence of structure. The background images created were found to contain long-lived structures, including coronal loops, that were still present in all of the wavelengths, 131, 171, 193, 211, and 335 A. The intensity profiles across the active region indicate that the background is much more structured than previously thought.

Advanced Background Subtraction Applied to Aeroacoustic Wind Tunnel Testing

NASA Technical Reports Server (NTRS)

Bahr, Christopher J.; Horne, William C.

2015-01-01

An advanced form of background subtraction is presented and applied to aeroacoustic wind tunnel data. A variant of this method has seen use in other fields such as climatology and medical imaging. The technique, based on an eigenvalue decomposition of the background noise cross-spectral matrix, is robust against situations where isolated background auto-spectral levels are measured to be higher than levels of combined source and background signals. It also provides an alternate estimate of the cross-spectrum, which previously might have poor definition for low signal-to-noise ratio measurements. Simulated results indicate similar performance to conventional background subtraction when the subtracted spectra are weaker than the true contaminating background levels. Superior performance is observed when the subtracted spectra are stronger than the true contaminating background levels. Experimental results show limited success in recovering signal behavior for data where conventional background subtraction fails. They also demonstrate the new subtraction technique's ability to maintain a proper coherence relationship in the modified cross-spectral matrix. Beam-forming and de-convolution results indicate the method can successfully separate sources. Results also show a reduced need for the use of diagonal removal in phased array processing, at least for the limited data sets considered.

PET attenuation correction for rigid MR Tx/Rx coils from 176Lu background activity

NASA Astrophysics Data System (ADS)

Lerche, Christoph W.; Kaltsas, Theodoris; Caldeira, Liliana; Scheins, Jürgen; Rota Kops, Elena; Tellmann, Lutz; Pietrzyk, Uwe; Herzog, Hans; Shah, N. Jon

2018-02-01

One challenge for PET-MR hybrid imaging is the correction for attenuation of the 511 keV annihilation radiation by the required RF transmit and/or RF receive coils. Although there are strategies for building PET transparent Tx/Rx coils, such optimised coils still cause significant attenuation of the annihilation radiation leading to artefacts and biases in the reconstructed activity concentrations. We present a straightforward method to measure the attenuation of Tx/Rx coils in simultaneous MR-PET imaging based on the natural 176Lu background contained in the scintillator of the PET detector without the requirement of an external CT scanner or PET scanner with transmission source. The method was evaluated on a prototype 3T MR-BrainPET produced by Siemens Healthcare GmbH, both with phantom studies and with true emission images from patient/volunteer examinations. Furthermore, the count rate stability of the PET scanner and the x-ray properties of the Tx/Rx head coil were investigated. Even without energy extrapolation from the two dominant γ energies of 176Lu to 511 keV, the presented method for attenuation correction, based on the measurement of 176Lu background attenuation, shows slightly better performance than the coil attenuation correction currently used. The coil attenuation correction currently used is based on an external transmission scan with rotating 68Ge sources acquired on a Siemens ECAT HR  +  PET scanner. However, the main advantage of the presented approach is its straightforwardness and ready availability without the need for additional accessories.

Current harmonics elimination control method for six-phase PM synchronous motor drives.

PubMed

Yuan, Lei; Chen, Ming-liang; Shen, Jian-qing; Xiao, Fei

2015-11-01

To reduce the undesired 5th and 7th stator harmonic current in the six-phase permanent magnet synchronous motor (PMSM), an improved vector control algorithm was proposed based on vector space decomposition (VSD) transformation method, which can control the fundamental and harmonic subspace separately. To improve the traditional VSD technology, a novel synchronous rotating coordinate transformation matrix was presented in this paper, and only using the traditional PI controller in d-q subspace can meet the non-static difference adjustment, the controller parameter design method is given by employing internal model principle. Moreover, the current PI controller parallel with resonant controller is employed in x-y subspace to realize the specific 5th and 7th harmonic component compensation. In addition, a new six-phase SVPWM algorithm based on VSD transformation theory is also proposed. Simulation and experimental results verify the effectiveness of current decoupling vector controller. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Apparatus and method for critical current measurements

DOEpatents

Martin, Joe A.; Dye, Robert C.

1992-01-01

An apparatus for the measurement of the critical current of a superconductive sample, e.g., a clad superconductive sample, the apparatus including a conductive coil, a means for maintaining the coil in proximity to a superconductive sample, an electrical connection means for passing a low amplitude alternating current through the coil, a cooling means for maintaining the superconductive sample at a preselected temperature, a means for passing a current through the superconductive sample, and, a means for monitoring reactance of the coil, is disclosed, together with a process of measuring the critical current of a superconductive material, e.g., a clad superconductive material, by placing a superconductive material into the vicinity of the conductive coil of such an apparatus, cooling the superconductive material to a preselected temperature, passing a low amplitude alternating current through the coil, the alternating current capable of generating a magnetic field sufficient to penetrate, e.g., any cladding, and to induce eddy currents in the superconductive material, passing a steadily increasing current through the superconductive material, the current characterized as having a different frequency than the alternating current, and, monitoring the reactance of the coil with a phase sensitive detector as the current passed through the superconductive material is steadily increased whereby critical current of the superconductive material can be observed as the point whereat a component of impedance deviates.

Investigation of Current Methods to Identify Helicopter Gear Health

NASA Technical Reports Server (NTRS)

Dempsey, Paula J.; Lewicki, David G.; Le, Dy D.

2007-01-01

This paper provides an overview of current vibration methods used to identify the health of helicopter transmission gears. The gears are critical to the transmission system that provides propulsion, lift and maneuvering of the helicopter. This paper reviews techniques used to process vibration data to calculate conditions indicators (CI's), guidelines used by the government aviation authorities in developing and certifying the Health and Usage Monitoring System (HUMS), condition and health indicators used in commercial HUMS, and different methods used to set thresholds to detect damage. Initial assessment of a method to set thresholds for vibration based condition indicators applied to flight and test rig data by evaluating differences in distributions between comparable transmissions are also discussed. Gear condition indicator FM4 values are compared on an OH58 helicopter during 14 maneuvers and an OH58 transmission test stand during crack propagation tests. Preliminary results show the distributions between healthy helicopter and rig data are comparable and distributions between healthy and damaged gears show significant differences.

Investigation of Current Methods to Identify Helicopter Gear Health

NASA Technical Reports Server (NTRS)

Dempsey, Paula J.; Lewicki, David G.; Le, Dy D.

2007-01-01

This paper provides an overview of current vibration methods used to identify the health of helicopter transmission gears. The gears are critical to the transmission system that provides propulsion, lift and maneuvering of the helicopter. This paper reviews techniques used to process vibration data to calculate conditions indicators (CI s), guidelines used by the government aviation authorities in developing and certifying the Health and Usage Monitoring System (HUMS), condition and health indicators used in commercial HUMS, and different methods used to set thresholds to detect damage. Initial assessment of a method to set thresholds for vibration based condition indicators applied to flight and test rig data by evaluating differences in distributions between comparable transmissions are also discussed. Gear condition indicator FM4 values are compared on an OH58 helicopter during 14 maneuvers and an OH58 transmission test stand during crack propagation tests. Preliminary results show the distributions between healthy helicopter and rig data are comparable and distributions between healthy and damaged gears show significant differences.

Application of neuro-fuzzy methods to gamma spectroscopy

NASA Astrophysics Data System (ADS)

Grelle, Austin L.

Nuclear non-proliferation activities are an essential part of national security activities both domestic and abroad. The safety of the public in densely populated environments such as urban areas or large events can be compromised if devices using special nuclear materials are present. Therefore, the prompt and accurate detection of these materials is an important topic of research, in which the identification of normal conditions is also of importance. With gamma-ray spectroscopy, these conditions are identified as the radiation background, which though being affected by a multitude of factors is ever present. Therefore, in nuclear non-proliferation activities the accurate identification of background is important. With this in mind, a method has been developed to utilize aggregate background data to predict the background of a location through the use of an Artificial Neural Network (ANN). After being trained on background data, the ANN is presented with nearby relevant gamma-ray spectroscopy data---as identified by a Fuzzy Inference System - to create a predicted background spectra to compare to a measured spectra. If a significant deviation exists between the predicted and measured data, the method alerts the user such that a more thorough investigation can take place. Research herein focused on data from an urban setting in which the number of false positives was observed to be 28 out of a total of 987, representing 2.94% error. The method therefore currently shows a high rate of false positives given the current configuration, however there are promising steps that can be taken to further minimize this error. With this in mind, the method stands as a potentially significant tool in urban nuclear nonproliferation activities.

Insights from the Source Physics Experiments on P/S Amplitude Ratio Methods of Identifying Explosions in a Background of Earthquakes

NASA Astrophysics Data System (ADS)

Walter, W. R.; Ford, S. R.; Xu, H.; Pasyanos, M. E.; Pyle, M. L.; Matzel, E.; Mellors, R. J.; Hauk, T. F.

2012-12-01

It is well established empirically that regional distance (200-1600 km) amplitude ratios of seismic P-to-S waves at sufficiently high frequencies (~>2 Hz) can identify explosions among a background of natural earthquakes. However the physical basis for the generation of explosion S-waves, and therefore the predictability of this P/S technique as a function of event properties such as size, depth, geology and path, remains incompletely understood. A goal of the Source Physics Experiments (SPE) at the Nevada National Security Site (NNSS, formerly the Nevada Test Site (NTS)) is to improve our physical understanding of the mechanisms of explosion S-wave generation and advance our ability to numerically model and predict them. Current models of explosion P/S values suggest they are frequency dependent with poor performance below the source corner frequencies and good performance above. This leads to expectations that small magnitude explosions might require much higher frequencies (>10 Hz) to identify them. Interestingly the 1-ton chemical source physics explosions SPE2 and SPE3 appear to discriminate well from background earthquakes in the frequency band 6-8 Hz, where P and S signals are visible at the NVAR array located near Mina, NV about 200 km away. NVAR is a primary seismic station in the International Monitoring System (IMS), part of the Comprehensive nuclear-Test-Ban Treaty (CTBT). The NVAR broadband element NV31 is co-located with the LLNL station MNV that recorded many NTS nuclear tests, allowing the comparison. We find the small SPE explosions in granite have similar Pn/Lg values at 6-8 Hz as the past nuclear tests mainly in softer rocks. We are currently examining a number of other stations in addition to NVAR, including the dedicated SPE stations that recorded the SPE explosions at much closer distances with very high sample rates, in order to better understand the observed frequency dependence as compared with the model predictions. We plan to use these

Estimating background-subtracted fluorescence transients in calcium imaging experiments: a quantitative approach.

PubMed

Joucla, Sébastien; Franconville, Romain; Pippow, Andreas; Kloppenburg, Peter; Pouzat, Christophe

2013-08-01

Calcium imaging has become a routine technique in neuroscience for subcellular to network level investigations. The fast progresses in the development of new indicators and imaging techniques call for dedicated reliable analysis methods. In particular, efficient and quantitative background fluorescence subtraction routines would be beneficial to most of the calcium imaging research field. A background-subtracted fluorescence transients estimation method that does not require any independent background measurement is therefore developed. This method is based on a fluorescence model fitted to single-trial data using a classical nonlinear regression approach. The model includes an appropriate probabilistic description of the acquisition system's noise leading to accurate confidence intervals on all quantities of interest (background fluorescence, normalized background-subtracted fluorescence time course) when background fluorescence is homogeneous. An automatic procedure detecting background inhomogeneities inside the region of interest is also developed and is shown to be efficient on simulated data. The implementation and performances of the proposed method on experimental recordings from the mouse hypothalamus are presented in details. This method, which applies to both single-cell and bulk-stained tissues recordings, should help improving the statistical comparison of fluorescence calcium signals between experiments and studies. Copyright © 2013 Elsevier Ltd. All rights reserved.

An Investigation of the Variety and Complexity of Statistical Methods Used in Current Internal Medicine Literature.

PubMed

Narayanan, Roshni; Nugent, Rebecca; Nugent, Kenneth

2015-10-01

. These papers used 128 statistical terms and context-defined concepts, including some from data analysis (56), epidemiology-biostatistics (31), modeling (24), data collection (12), and meta-analysis (5). Ten different software programs were used in these articles. Based on usual undergraduate and graduate statistics curricula, 64.3% of the concepts and methods used in these papers required at least a master's degree-level statistics education. The interpretation of the current medical literature can require an extensive background in statistical methods at an education level exceeding the material and resources provided to most medical students and residents. Given the complexity and time pressure of medical education, these deficiencies will be hard to correct, but this project can serve as a basis for developing a curriculum in study design and statistical methods needed by physicians-in-training.

Substance P Depolarizes Lamprey Spinal Cord Neurons by Inhibiting Background Potassium Channels.

PubMed

Thörn Pérez, Carolina; Hill, Russell H; Grillner, Sten

2015-01-01

Substance P is endogenously released in the adult lamprey spinal cord and accelerates the burst frequency of fictive locomotion. This is achieved by multiple effects on interneurons and motoneurons, including an attenuation of calcium currents, potentiation of NMDA currents and reduction of the reciprocal inhibition. While substance P also depolarizes spinal cord neurons, the underlying mechanism has not been resolved. Here we show that effects of substance P on background K+ channels are the main source for this depolarization. Hyperpolarizing steps induced inward currents during whole-cell voltage clamp that were reduced by substance P. These background K+ channels are pH sensitive and are selectively blocked by anandamide and AVE1231. These blockers counteracted the effect of substance P on these channels and the resting membrane potential depolarization in spinal cord neurons. Thus, we have shown now that substance P inhibits background K+ channels that in turn induce depolarization, which is likely to contribute to the frequency increase observed with substance P during fictive locomotion.

Background of SAM atom-fraction profiles

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

Ernst, Frank

Atom-fraction profiles acquired by SAM (scanning Auger microprobe) have important applications, e.g. in the context of alloy surface engineering by infusion of carbon or nitrogen through the alloy surface. However, such profiles often exhibit an artifact in form of a background with a level that anti-correlates with the local atom fraction. This article presents a theory explaining this phenomenon as a consequence of the way in which random noise in the spectrum propagates into the discretized differentiated spectrum that is used for quantification. The resulting model of “energy channel statistics” leads to a useful semi-quantitative background reduction procedure, which ismore » validated by applying it to simulated data. Subsequently, the procedure is applied to an example of experimental SAM data. The analysis leads to conclusions regarding optimum experimental acquisition conditions. The proposed method of background reduction is based on general principles and should be useful for a broad variety of applications. - Highlights: • Atom-fraction–depth profiles of carbon measured by scanning Auger microprobe • Strong background, varies with local carbon concentration. • Needs correction e.g. for quantitative comparison with simulations • Quantitative theory explains background. • Provides background removal strategy and practical advice for acquisition.« less

Methods, systems and apparatus for synchronous current regulation of a five-phase machine

DOEpatents

Gallegos-Lopez, Gabriel; Perisic, Milun

2012-10-09

Methods, systems and apparatus are provided for controlling operation of and regulating current provided to a five-phase machine when one or more phases has experienced a fault or has failed. In one implementation, the disclosed embodiments can be used to synchronously regulate current in a vector controlled motor drive system that includes a five-phase AC machine, a five-phase inverter module coupled to the five-phase AC machine, and a synchronous current regulator.

Determining the near-surface current profile from measurements of the wave dispersion relation

NASA Astrophysics Data System (ADS)

Smeltzer, Benjamin; Maxwell, Peter; Aesøy, Eirik; Ellingsen, Simen

2017-11-01

The current-induced Doppler shifts of waves can yield information about the background mean flow, providing an attractive method of inferring the current profile in the upper layer of the ocean. We present measurements of waves propagating on shear currents in a laboratory water channel, as well as theoretical investigations of inversion techniques for determining the vertical current structure. Spatial and temporal measurements of the free surface profile obtained using a synthetic Schlieren method are analyzed to determine the wave dispersion relation and Doppler shifts as a function of wavelength. The vertical current profile can then be inferred from the Doppler shifts using an inversion algorithm. Most existing algorithms rely on a priori assumptions of the shape of the current profile, and developing a method that uses less stringent assumptions is a focus of this study, allowing for measurement of more general current profiles. The accuracy of current inversion algorithms are evaluated by comparison to measurements of the mean flow profile from particle image velocimetry (PIV), and a discussion of the sensitivity to errors in the Doppler shifts is presented.

A Limited In-Flight Evaluation of the Constant Current Loop Strain Measurement Method

NASA Technical Reports Server (NTRS)

Olney, Candida D.; Collura, Joseph V.

1997-01-01

For many years, the Wheatstone bridge has been used successfully to measure electrical resistance and changes in that resistance. However, the inherent problem of varying lead wire resistance can cause errors when the Wheatstone bridge is used to measure strain in a flight environment. The constant current loop signal-conditioning card was developed to overcome that difficulty. This paper describes a limited evaluation of the constant current loop strain measurement method as used in the F-16XL ship 2 Supersonic Laminar Flow Control flight project. Several identical strain gages were installed in close proximity on a shock fence which was mounted under the left wing of the F- 1 6XL ship 2. Two strain gage bridges were configured using the constant current loop, and two were configured using the Wheatstone bridge circuitry. Flight data comparing the output from the constant current loop configured gages to that of the Wheatstone bridges with respect to signal output, error, and noise are given. Results indicate that the constant current loop strain measurement method enables an increased output, unaffected by lead wire resistance variations, to be obtained from strain gages.

Holographic Methods Of Dynamic Particulate Measurements ¬â€?Current Status

NASA Astrophysics Data System (ADS)

Thompson, Brian J.

1983-03-01

The field of holographic particulate measurements continues to be very active with many new applications in such diverse fields as bubble chamber recording and contaminant measurements in small vials. The methods have also been extended to measure velocity distributions of particles within a volume, particularly by the application of subsequent image processing methods. These techniques could be coupled with hybrid systems to become near real time. The current status of these more recent developments is reviewed.

Constraining Modified Theories of Gravity with Gravitational-Wave Stochastic Backgrounds

NASA Astrophysics Data System (ADS)

Maselli, Andrea; Marassi, Stefania; Ferrari, Valeria; Kokkotas, Kostas; Schneider, Raffaella

2016-08-01

The direct discovery of gravitational waves has finally opened a new observational window on our Universe, suggesting that the population of coalescing binary black holes is larger than previously expected. These sources produce an unresolved background of gravitational waves, potentially observable by ground-based interferometers. In this Letter we investigate how modified theories of gravity, modeled using the parametrized post-Einsteinian formalism, affect the expected signal, and analyze the detectability of the resulting stochastic background by current and future ground-based interferometers. We find the constraints that Advanced LIGO would be able to set on modified theories, showing that they may significantly improve the current bounds obtained from astrophysical observations of binary pulsars.

[Methods of brain stimulation based on weak electric current--future tool for the clinician?].

PubMed

Kotilainen, Tuukka; Lehto, Soili M

2016-01-01

Methods of brain stimulation based on a weak electric current are non-invasive neuromodulation techniques. They include transcranial direct current, alternating current and random noise stimulation. These methods modify the membrane potential of neurons without triggering the action potential, and have been successfully utilized to influence cognition and regulation of emotions in healthy experimental subjects. In clinical studies, indications of the efficacy of these techniques have been obtained in the treatment of depression, schizophrenia, memory disorders and pain as well as in stroke rehabilitation. It is hoped that these techniques will become established as part of the care and rehabilitation of psychiatric and neurologic patients in the future.

30 CFR 77.701-1 - Approved methods of grounding of equipment receiving power from ungrounded alternating current...

Code of Federal Regulations, 2011 CFR

2011-07-01

... receiving power from ungrounded alternating current power systems. 77.701-1 Section 77.701-1 Mineral...-1 Approved methods of grounding of equipment receiving power from ungrounded alternating current... receiving power from ungrounded alternating current power systems, the following methods of grounding will...

30 CFR 77.701-1 - Approved methods of grounding of equipment receiving power from ungrounded alternating current...

Code of Federal Regulations, 2010 CFR

2010-07-01

... receiving power from ungrounded alternating current power systems. 77.701-1 Section 77.701-1 Mineral...-1 Approved methods of grounding of equipment receiving power from ungrounded alternating current... receiving power from ungrounded alternating current power systems, the following methods of grounding will...

Background suppression of infrared small target image based on inter-frame registration

NASA Astrophysics Data System (ADS)

Ye, Xiubo; Xue, Bindang

2018-04-01

We propose a multi-frame background suppression method for remote infrared small target detection. Inter-frame information is necessary when the heavy background clutters make it difficult to distinguish real targets and false alarms. A registration procedure based on points matching in image patches is used to compensate the local deformation of background. Then the target can be separated by background subtraction. Experiments show our method serves as an effective preliminary of target detection.

Current Methods for Skeletal Muscle Tissue Repair and Regeneration

PubMed Central

Liu, Juan; Saul, Dominik; Böker, Kai Oliver; Ernst, Jennifer; Lehman, Wolfgang

2018-01-01

Skeletal muscle has the capacity of regeneration after injury. However, for large volumes of muscle loss, this regeneration needs interventional support. Consequently, muscle injury provides an ongoing reconstructive and regenerative challenge in clinical work. To promote muscle repair and regeneration, different strategies have been developed within the last century and especially during the last few decades, including surgical techniques, physical therapy, biomaterials, and muscular tissue engineering as well as cell therapy. Still, there is a great need to develop new methods and materials, which promote skeletal muscle repair and functional regeneration. In this review, we give a comprehensive overview over the epidemiology of muscle tissue loss, highlight current strategies in clinical treatment, and discuss novel methods for muscle regeneration and challenges for their future clinical translation. PMID:29850487

Non-destructive testing of composite materials used in military applications by eddy current thermography method

NASA Astrophysics Data System (ADS)

Swiderski, Waldemar

2016-10-01

Eddy current thermography is a new NDT-technique for the detection of cracks in electro conductive materials. It combines the well-established inspection techniques of eddy current testing and thermography. The technique uses induced eddy currents to heat the sample being tested and defect detection is based on the changes of induced eddy currents flows revealed by thermal visualization captured by an infrared camera. The advantage of this method is to use the high performance of eddy current testing that eliminates the known problem of the edge effect. Especially for components of complex geometry this is an important factor which may overcome the increased expense for inspection set-up. The paper presents the possibility of applying eddy current thermography method for detecting defects in ballistic covers made of carbon fiber reinforced composites used in the construction of military vehicles.

Estimation of channel parameters and background irradiance for free-space optical link.

PubMed

Khatoon, Afsana; Cowley, William G; Letzepis, Nick; Giggenbach, Dirk

2013-05-10

Free-space optical communication can experience severe fading due to optical scintillation in long-range links. Channel estimation is also corrupted by background and electrical noise. Accurate estimation of channel parameters and scintillation index (SI) depends on perfect removal of background irradiance. In this paper, we propose three different methods, the minimum-value (MV), mean-power (MP), and maximum-likelihood (ML) based methods, to remove the background irradiance from channel samples. The MV and MP methods do not require knowledge of the scintillation distribution. While the ML-based method assumes gamma-gamma scintillation, it can be easily modified to accommodate other distributions. Each estimator's performance is compared using simulation data as well as experimental measurements. The estimators' performance are evaluated from low- to high-SI areas using simulation data as well as experimental trials. The MV and MP methods have much lower complexity than the ML-based method. However, the ML-based method shows better SI and background-irradiance estimation performance.

Implementation of a flow-dependent background error correlation length scale formulation in the NEMOVAR OSTIA system

NASA Astrophysics Data System (ADS)

Fiedler, Emma; Mao, Chongyuan; Good, Simon; Waters, Jennifer; Martin, Matthew

2017-04-01

OSTIA is the Met Office's Operational Sea Surface Temperature (SST) and Ice Analysis system, which produces L4 (globally complete, gridded) analyses on a daily basis. Work is currently being undertaken to replace the original OI (Optimal Interpolation) data assimilation scheme with NEMOVAR, a 3D-Var data assimilation method developed for use with the NEMO ocean model. A dual background error correlation length scale formulation is used for SST in OSTIA, as implemented in NEMOVAR. Short and long length scales are combined according to the ratio of the decomposition of the background error variances into short and long spatial correlations. The pre-defined background error variances vary spatially and seasonally, but not on shorter time-scales. If the derived length scales applied to the daily analysis are too long, SST features may be smoothed out. Therefore a flow-dependent component to determining the effective length scale has also been developed. The total horizontal gradient of the background SST field is used to identify regions where the length scale should be shortened. These methods together have led to an improvement in the resolution of SST features compared to the previous OI analysis system, without the introduction of spurious noise. This presentation will show validation results for feature resolution in OSTIA using the OI scheme, the dual length scale NEMOVAR scheme, and the flow-dependent implementation.

Revisiting Antipsychotic-induced Akathisia: Current Issues and Prospective Challenges

PubMed Central

Salem, Haitham; Nagpal, Caesa; Pigott, Teresa; Teixeira, Antonio Lucio

2017-01-01

Background: Akathisia continues to be a significant challenge in current neurological and psychiatric practice. Prompt and accurate detection is often difficult and there is a lack of consensus concerning the neurobiological basis of akathisia. No definitive treatment has been established for akathisia despite numerous preclinical and clinical studies. Method: We reviewed antipsychotic-induced akathisia including its clinical presentation, proposed underlying pathophysiology, current and under investigation therapeutic strategies. Conclusion: Despite the initial promise that second generation antipsychotics would be devoid of akathisia effects, this has not been confirmed. Currently, there are limited therapeutic options for the clinical practice and the evidence supporting the most widely used treatments (beta blockers, anticholinergic drugs) is still absent or inconsistent. PMID:27928948

Basics of Bayesian methods.

PubMed

Ghosh, Sujit K

2010-01-01

Bayesian methods are rapidly becoming popular tools for making statistical inference in various fields of science including biology, engineering, finance, and genetics. One of the key aspects of Bayesian inferential method is its logical foundation that provides a coherent framework to utilize not only empirical but also scientific information available to a researcher. Prior knowledge arising from scientific background, expert judgment, or previously collected data is used to build a prior distribution which is then combined with current data via the likelihood function to characterize the current state of knowledge using the so-called posterior distribution. Bayesian methods allow the use of models of complex physical phenomena that were previously too difficult to estimate (e.g., using asymptotic approximations). Bayesian methods offer a means of more fully understanding issues that are central to many practical problems by allowing researchers to build integrated models based on hierarchical conditional distributions that can be estimated even with limited amounts of data. Furthermore, advances in numerical integration methods, particularly those based on Monte Carlo methods, have made it possible to compute the optimal Bayes estimators. However, there is a reasonably wide gap between the background of the empirically trained scientists and the full weight of Bayesian statistical inference. Hence, one of the goals of this chapter is to bridge the gap by offering elementary to advanced concepts that emphasize linkages between standard approaches and full probability modeling via Bayesian methods.

Method for confining the magnetic field of the cross-tail current inside the magnetopause

NASA Technical Reports Server (NTRS)

Sotirelis, T.; Tsyganenko, N. A.; Stern, D. P.

1994-01-01

A method is presented for analytically representing the magnetic field due to the cross-tail current and its closure on the magnetopause. It is an extension of a method used by Tsyganenko (1989b) to confine the dipole field inside an ellipsoidal magnetopause using a scalar potential. Given a model of the cross-tail current, the implied net magnetic field is obtained by adding to the cross-tail current field a potential field B = - del gamma, which makes all field lines divide into two disjoint groups, separated by the magnetopause (i.e., the combined field is made to have zero normal component with the magnetopause). The magnetopause is assumed to be an ellipsoid of revolution (a prolate spheroid) as an approximation to observations (Sibeck et al., 1991). This assumption permits the potential gamma to be expressed in spheroidal coordinates, expanded in spheroidal harmonics and its terms evaluated by performing inversion integrals. Finally, the field outside the magnetopause is replaced by zero, resulting in a consistent current closure along the magnetopause. This procedure can also be used to confine the modeled field of any other interior magnetic source, though the model current must always flow in closed circuits. The method is demonstrated on the T87 cross-tail current, examples illustrate the effect of changing the size and shape of the prescribed magnetopause and a comparison is made to an independent numerical scheme based on the Biot-Savart equation.

Low-background Gamma Spectroscopy at Sanford Underground Laboratory

NASA Astrophysics Data System (ADS)

Chiller, Christopher; Alanson, Angela; Mei, Dongming

2014-03-01

Rare-event physics experiments require the use of material with unprecedented radio-purity. Low background counting assay capabilities and detectors are critical for determining the sensitivity of the planned ultra-low background experiments. A low-background counting, LBC, facility has been built at the 4850-Level Davis Campus of the Sanford Underground Research Facility to perform screening of material and detector parts. Like many rare event physics experiments, our LBC uses lead shielding to mitigate background radiation. Corrosion of lead brick shielding in subterranean installations creates radon plate-out potential as well as human risks of ingestible or respirable lead compounds. Our LBC facilities employ an exposed lead shield requiring clean smooth surfaces. A cleaning process of low-activity silica sand blasting and borated paraffin hot coating preservation was employed to guard against corrosion due to chemical and biological exposures. The resulting lead shield maintains low background contribution integrity while fully encapsulating the lead surface. We report the performance of the current LBC and a plan to develop a large germanium well detector for PMT screening. Support provided by Sd governors research center-CUBED, NSF PHY-0758120 and Sanford Lab.

Diagnosing cystic fibrosis-related diabetes: current methods and challenges.

PubMed

Prentice, Bernadette; Hameed, Shihab; Verge, Charles F; Ooi, Chee Y; Jaffe, Adam; Widger, John

2016-07-01

Cystic fibrosis-related diabetes (CFRD) is the end-point of a spectrum of glucose abnormalities in cystic fibrosis that begins with early insulin deficiency and ultimately results in accelerated nutritional decline and loss of lung function. Current diagnostic and management regimens are unable to entirely reverse this clinical decline. This review summarises the current understanding of the pathophysiology of CFRD, the issues associated with using oral glucose tolerance tests in CF and the challenges faced in making the diagnosis of CFRD. Medline database searches were conducted using search terms "Cystic Fibrosis Related Diabetes", "Cystic Fibrosis" AND "glucose", "Cystic Fibrosis" AND "insulin", "Cystic Fibrosis" AND "Diabetes". Additionally, reference lists were studied. Expert commentary: Increasing evidence points to early glucose abnormalities being clinically relevant in cystic fibrosis and as such novel diagnostic methods such as continuous glucose monitoring or 30 minute sampled oral glucose tolerance test (OGTT) may play a key role in the future in the screening and diagnosis of early glucose abnormalities in CF.

Current Progress in Gene Delivery Technology Based on Chemical Methods and Nano-carriers

PubMed Central

Jin, Lian; Zeng, Xin; Liu, Ming; Deng, Yan; He, Nongyue

2014-01-01

Gene transfer methods are promising in the field of gene therapy. Current methods for gene transfer include three major groups: viral, physical and chemical methods. This review mainly summarizes development of several types of chemical methods for gene transfer in vitro and in vivo by means of nano-carriers like; calcium phosphates, lipids, and cationic polymers including chitosan, polyethylenimine, polyamidoamine dendrimers, and poly(lactide-co-glycolide). This review also briefly introduces applications of these chemical methods for gene delivery. PMID:24505233

Methods for stable recording of short-circuit current in a Na+-transporting epithelium.

PubMed

Gondzik, Veronika; Awayda, Mouhamed S

2011-07-01

Epithelial Na(+) transport as measured by a variety of techniques, including the short-circuit current technique, has been described to exhibit a "rundown" phenomenon. This phenomenon manifests as time-dependent decrease of current and resistance and precludes the ability to carry out prolonged experiments aimed at examining the regulation of this transport. We developed methods for prolonged stable recordings of epithelial Na(+) transport using modifications of the short-circuit current technique and commercial Ussing-type chambers. We utilize the polarized MDCK cell line expressing the epithelial Na(+) channel (ENaC) to describe these methods. Briefly, existing commercial chambers were modified to allow continuous flow of Ringer solution and precise control of such flow. Chamber manifolds and associated plumbing were modified to allow precise temperature clamp preventing temperature oscillations. Recording electrodes were modified to eliminate the use of KCl and prevent membrane depolarization from KCl leakage. Solutions utilized standard bicarbonate-based buffers, but all gasses were prehydrated to clamp buffer osmolarity. We demonstrate that these modifications result in measurements of current and resistance that are stable for at least 2 h. We further demonstrate that drifts in osmolarity similar to those obtained before prior to our modifications can lead to a decrease of current and resistance similar to those attributed to rundown.

Reverse Current Shock Induced by Plasma-Neutral Collision

NASA Astrophysics Data System (ADS)

Wongwaitayakornkul, Pakorn; Haw, Magnus; Li, Hui; Li, Shengtai; Bellan, Paul

2017-10-01

The Caltech solar experiment creates an arched plasma-filled flux rope expanding into low density background plasma. A layer of electrical current flowing in the opposite direction with respect to the flux rope current is induced in the background plasma just ahead of the flux rope. Two dimensional spatial and temporal measurements by a 3-dimensional magnetic vector probe demonstrate the existence of this induced current layer forming ahead of the flux rope. The induced current magnitude is 20% of the magnitude of the current in the flux rope. The reverse current in the low density background plasma is thought to be a diamagnetic response that shields out the magnetic field ahead of the propagation. The spatial and magnetic characteristics of the reverse current layer are consistent with similar shock structures seen in 3-dimensional ideal MHD numerical simulations performed on the Turquoise supercomputer cluster using the Los Alamos COMPutational Astrophysics Simulation Suite. This discovery of the induced diamagnetic current provides useful insights for space and solar plasma.

Background Characterization for Thermal Ion Release Experiments with 224Ra

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

Kwong, H.; /Stanford U., Phys. Dept.; Rowson, P.

The Enriched Xenon Observatory for neutrinoless double beta decay uses {sup 136}Ba identification as a means for verifying the decay's occurrence in {sup 136}Xe. A current challenge is the release of Ba ions from the Ba extraction probe, and one possible solution is to heat the probe to high temperatures to release the ions. The investigation of this method requires a characterization of the alpha decay background in our test apparatus, which uses a {sup 228}Th source that produces {sup 224}Ra daughters, the ionization energies of which are similar to those of Ba. For this purpose, we ran a backgroundmore » count with our apparatus maintained at a vacuum, and then three counts with the apparatus filled with Xe gas. We were able to match up our alpha spectrum in vacuum with the known decay scheme of {sup 228}Th, while the spectrum in xenon gas had too many unresolved ambiguities for an accurate characterization. We also found that the alpha decays occurred at a near-zero rate both in vacuum and in xenon gas, which indicates that the rate was determined by {sup 228}Th decays. With these background measurements, we can in the future make a more accurate measurement of the temperature dependency of the ratio of ions to neutral atoms released from the hot surface of the probe, which may lead to a successful method of Ba ion release.« less

Analysis of Alpha Backgrounds in DarkSide-50

NASA Astrophysics Data System (ADS)

Monte, Alissa; DarkSide Collaboration

2017-01-01

DarkSide-50 is the current phase of the DarkSide direct dark matter search program, operating underground at the Laboratori Nazionali del Gran Sasso in Italy. The detector is a dual-phase argon Time Projection Chamber (TPC), designed for direct detection of Weakly Interacting Massive Particles, and housed within an active veto system of liquid scintillator and water Cherenkov detectors. Since switching to a target of low radioactivity argon extracted from underground sources in April, 2016, the background is no longer dominated by naturally occurring 39Ar. However, alpha backgrounds from radon and its daughters remain, both from the liquid argon bulk and internal detector surfaces. I will present details of the analysis used to understand and quantify alpha backgrounds, as well as to understand other types of radon contamination that may be present, and our sensitivity to them.

Parameter estimation for the exponential-normal convolution model for background correction of affymetrix GeneChip data.

PubMed

McGee, Monnie; Chen, Zhongxue

2006-01-01

There are many methods of correcting microarray data for non-biological sources of error. Authors routinely supply software or code so that interested analysts can implement their methods. Even with a thorough reading of associated references, it is not always clear how requisite parts of the method are calculated in the software packages. However, it is important to have an understanding of such details, as this understanding is necessary for proper use of the output, or for implementing extensions to the model. In this paper, the calculation of parameter estimates used in Robust Multichip Average (RMA), a popular preprocessing algorithm for Affymetrix GeneChip brand microarrays, is elucidated. The background correction method for RMA assumes that the perfect match (PM) intensities observed result from a convolution of the true signal, assumed to be exponentially distributed, and a background noise component, assumed to have a normal distribution. A conditional expectation is calculated to estimate signal. Estimates of the mean and variance of the normal distribution and the rate parameter of the exponential distribution are needed to calculate this expectation. Simulation studies show that the current estimates are flawed; therefore, new ones are suggested. We examine the performance of preprocessing under the exponential-normal convolution model using several different methods to estimate the parameters.

Method and apparatus for generating motor current spectra to enhance motor system fault detection

DOEpatents

Linehan, Daniel J.; Bunch, Stanley L.; Lyster, Carl T.

1995-01-01

A method and circuitry for sampling periodic amplitude modulations in a nonstationary periodic carrier wave to determine frequencies in the amplitude modulations. The method and circuit are described in terms of an improved motor current signature analysis. The method insures that the sampled data set contains an exact whole number of carrier wave cycles by defining the rate at which samples of motor current data are collected. The circuitry insures that a sampled data set containing stationary carrier waves is recreated from the analog motor current signal containing nonstationary carrier waves by conditioning the actual sampling rate to adjust with the frequency variations in the carrier wave. After the sampled data is transformed to the frequency domain via the Discrete Fourier Transform, the frequency distribution in the discrete spectra of those components due to the carrier wave and its harmonics will be minimized so that signals of interest are more easily analyzed.

Method and apparatus for generating motor current spectra to enhance motor system fault detection

DOEpatents

Linehan, D.J.; Bunch, S.L.; Lyster, C.T.

1995-10-24

A method and circuitry are disclosed for sampling periodic amplitude modulations in a nonstationary periodic carrier wave to determine frequencies in the amplitude modulations. The method and circuit are described in terms of an improved motor current signature analysis. The method insures that the sampled data set contains an exact whole number of carrier wave cycles by defining the rate at which samples of motor current data are collected. The circuitry insures that a sampled data set containing stationary carrier waves is recreated from the analog motor current signal containing nonstationary carrier waves by conditioning the actual sampling rate to adjust with the frequency variations in the carrier wave. After the sampled data is transformed to the frequency domain via the Discrete Fourier Transform, the frequency distribution in the discrete spectra of those components due to the carrier wave and its harmonics will be minimized so that signals of interest are more easily analyzed. 29 figs.

Substance P Depolarizes Lamprey Spinal Cord Neurons by Inhibiting Background Potassium Channels

PubMed Central

Thörn Pérez, Carolina; Hill, Russell H.; Grillner, Sten

2015-01-01

Substance P is endogenously released in the adult lamprey spinal cord and accelerates the burst frequency of fictive locomotion. This is achieved by multiple effects on interneurons and motoneurons, including an attenuation of calcium currents, potentiation of NMDA currents and reduction of the reciprocal inhibition. While substance P also depolarizes spinal cord neurons, the underlying mechanism has not been resolved. Here we show that effects of substance P on background K+ channels are the main source for this depolarization. Hyperpolarizing steps induced inward currents during whole-cell voltage clamp that were reduced by substance P. These background K+ channels are pH sensitive and are selectively blocked by anandamide and AVE1231. These blockers counteracted the effect of substance P on these channels and the resting membrane potential depolarization in spinal cord neurons. Thus, we have shown now that substance P inhibits background K+ channels that in turn induce depolarization, which is likely to contribute to the frequency increase observed with substance P during fictive locomotion. PMID:26197458

An EPIC Tale of the Quiescent Particle Background

NASA Technical Reports Server (NTRS)

Snowden, S.L.; Kuntz, K.D.

2017-01-01

Extended Source Analysis Software Use Based Empirical Investigation: (1) Builds quiescent particle background (QPB) spectra and images for observations of extended sources that fill (or mostly fill) the FOV i.e., annular background subtraction won't work. (2) Uses a combination of Filter Wheel Closed (FWC) and corner data to capture the spectral, spatial, and temporal variation of the quiescent particle background. New Work: (1) Improved understanding of the QPB (aided by adding a whole lot of data since 2008). (2) Significantly improved statistics (did I mention a LOT more data?). (3) Better characterization and identification of anomalous states. (4) Builds backgrounds for some anomalous state. (5) New efficient method for non-anomalous states.

Background concentrations for high resolution satellite observing systems of methane

NASA Astrophysics Data System (ADS)

Benmergui, J. S.; Propp, A. M.; Turner, A. J.; Wofsy, S. C.

2017-12-01

Emerging satellite technologies promise to measure total column dry-air mole fractions of methane (XCH4) at resolutions on the order of a kilometer. XCH4 is linearly related to regional methane emissions through enhancements in the mixed layer, giving these satellites the ability to constrain emissions at unprecedented resolution. However, XCH4 is also sensitive to variability in transport of upwind concentrations (the "background concentration"). Variations in the background concentration are caused by synoptic scale transport in both the free troposphere and the stratosphere, as well as the rate of methane oxidation. Misspecification of the background concentration is aliased onto retrieved emissions as bias. This work explores several methods of specifying the background concentration for high resolution satellite observations of XCH4. We conduct observing system simulation experiments (OSSEs) that simulate the retrieval of emissions in the Barnett Shale using observations from a 1.33 km resolution XCH4 imaging satellite. We test background concentrations defined (1) from an external continental-scale model, (2) using pixels along the edge of the image as a boundary value, (3) using differences between adjacent pixels, and (4) using differences between the same pixel separated by one hour in time. We measure success using the accuracy of the retrieval, the potential for bias induced by misspecification of the background, and the computational expedience of the method. Pathological scenarios are given to each method.

Simple automatic strategy for background drift correction in chromatographic data analysis.

PubMed

Fu, Hai-Yan; Li, He-Dong; Yu, Yong-Jie; Wang, Bing; Lu, Peng; Cui, Hua-Peng; Liu, Ping-Ping; She, Yuan-Bin

2016-06-03

Chromatographic background drift correction, which influences peak detection and time shift alignment results, is a critical stage in chromatographic data analysis. In this study, an automatic background drift correction methodology was developed. Local minimum values in a chromatogram were initially detected and organized as a new baseline vector. Iterative optimization was then employed to recognize outliers, which belong to the chromatographic peaks, in this vector, and update the outliers in the baseline until convergence. The optimized baseline vector was finally expanded into the original chromatogram, and linear interpolation was employed to estimate background drift in the chromatogram. The principle underlying the proposed method was confirmed using a complex gas chromatographic dataset. Finally, the proposed approach was applied to eliminate background drift in liquid chromatography quadrupole time-of-flight samples used in the metabolic study of Escherichia coli samples. The proposed method was comparable with three classical techniques: morphological weighted penalized least squares, moving window minimum value strategy and background drift correction by orthogonal subspace projection. The proposed method allows almost automatic implementation of background drift correction, which is convenient for practical use. Copyright © 2016 Elsevier B.V. All rights reserved.

Study on model current predictive control method of PV grid- connected inverters systems with voltage sag

NASA Astrophysics Data System (ADS)

Jin, N.; Yang, F.; Shang, S. Y.; Tao, T.; Liu, J. S.

2016-08-01

According to the limitations of the LVRT technology of traditional photovoltaic inverter existed, this paper proposes a low voltage ride through (LVRT) control method based on model current predictive control (MCPC). This method can effectively improve the photovoltaic inverter output characteristics and response speed. The MCPC method of photovoltaic grid-connected inverter designed, the sum of the absolute value of the predictive current and the given current error is adopted as the cost function with the model predictive control method. According to the MCPC, the optimal space voltage vector is selected. Photovoltaic inverter has achieved automatically switches of priority active or reactive power control of two control modes according to the different operating states, which effectively improve the inverter capability of LVRT. The simulation and experimental results proves that the proposed method is correct and effective.

Cosmic Microwave Background Polarization and Inflation

NASA Technical Reports Server (NTRS)

Chuss, David T.

2011-01-01

Measurements of the cosmic microwave background (CMB) offer a means to explore the universe at a very early epoch. Specifically, if the universe went through a brief period of exponential expansion called inflation as current data suggest, gravitational waves from this period would polarize the CMB in a specific pattern. At GSFC, we are currently working towards two experiments that work in concert to measure this polarization pattern in search of evidence for inflation. The Cosmology Large Angular Scale Surveyor (CLASS) will measure the polarization at frequencies between 40 and 150 GHz from the Atacama Desert in Chile. The Primordial Inflation Polarization Explorer (PIPER) is a balloon-borne experiment that will make similar measurements at frequencies between 200 and 600 GHz.

Adaptive removal of background and white space from document images using seam categorization

NASA Astrophysics Data System (ADS)

Fillion, Claude; Fan, Zhigang; Monga, Vishal

2011-03-01

Document images are obtained regularly by rasterization of document content and as scans of printed documents. Resizing via background and white space removal is often desired for better consumption of these images, whether on displays or in print. While white space and background are easy to identify in images, existing methods such as naïve removal and content aware resizing (seam carving) each have limitations that can lead to undesirable artifacts, such as uneven spacing between lines of text or poor arrangement of content. An adaptive method based on image content is hence needed. In this paper we propose an adaptive method to intelligently remove white space and background content from document images. Document images are different from pictorial images in structure. They typically contain objects (text letters, pictures and graphics) separated by uniform background, which include both white paper space and other uniform color background. Pixels in uniform background regions are excellent candidates for deletion if resizing is required, as they introduce less change in document content and style, compared with deletion of object pixels. We propose a background deletion method that exploits both local and global context. The method aims to retain the document structural information and image quality.

Characterizing the True Background Corona with SDO/AIA

NASA Technical Reports Server (NTRS)

Napier, Kate; Winebarger, Amy; Alexander, Caroline

2014-01-01

Characterizing the nature of the solar coronal background would enable scientists to more accurately determine plasma parameters, and may lead to a better understanding of the coronal heating problem. Because scientists study the 3D structure of the Sun in 2D, any line of sight includes both foreground and background material, and thus, the issue of background subtraction arises. By investigating the intensity values in and around an active region, using multiple wavelengths collected from the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO) over an eight-hour period, this project aims to characterize the background as smooth or structured. Different methods were employed to measure the true coronal background and create minimum intensity images. These were then investigated for the presence of structure. The background images created were found to contain long-lived structures, including coronal loops, that were still present in all of the wavelengths, 193 Angstroms,171 Angstroms,131 Angstroms, and 211 Angstroms. The intensity profiles across the active region indicate that the background is much more structured than previously thought.

An efficient 3-D eddy-current solver using an independent impedance method for transcranial magnetic stimulation.

PubMed

De Geeter, Nele; Crevecoeur, Guillaume; Dupre, Luc

2011-02-01

In many important bioelectromagnetic problem settings, eddy-current simulations are required. Examples are the reduction of eddy-current artifacts in magnetic resonance imaging and techniques, whereby the eddy currents interact with the biological system, like the alteration of the neurophysiology due to transcranial magnetic stimulation (TMS). TMS has become an important tool for the diagnosis and treatment of neurological diseases and psychiatric disorders. A widely applied method for simulating the eddy currents is the impedance method (IM). However, this method has to contend with an ill conditioned problem and consequently a long convergence time. When dealing with optimal design problems and sensitivity control, the convergence rate becomes even more crucial since the eddy-current solver needs to be evaluated in an iterative loop. Therefore, we introduce an independent IM (IIM), which improves the conditionality and speeds up the numerical convergence. This paper shows how IIM is based on IM and what are the advantages. Moreover, the method is applied to the efficient simulation of TMS. The proposed IIM achieves superior convergence properties with high time efficiency, compared to the traditional IM and is therefore a useful tool for accurate and fast TMS simulations.

Characterization of background concentrations of contaminants using a mixture of normal distributions.

PubMed

Qian, Song S; Lyons, Regan E

2006-10-01

We present a Bayesian approach for characterizing background contaminant concentration distributions using data from sites that may have been contaminated. Our method, focused on estimation, resolves several technical problems of the existing methods sanctioned by the U.S. Environmental Protection Agency (USEPA) (a hypothesis testing based method), resulting in a simple and quick procedure for estimating background contaminant concentrations. The proposed Bayesian method is applied to two data sets from a federal facility regulated under the Resource Conservation and Restoration Act. The results are compared to background distributions identified using existing methods recommended by the USEPA. The two data sets represent low and moderate levels of censorship in the data. Although an unbiased estimator is elusive, we show that the proposed Bayesian estimation method will have a smaller bias than the EPA recommended method.

Age of First Use as a Predictor of Current Alcohol and Marijuana Use among College-Bound Emerging Adults

ERIC Educational Resources Information Center

Bergen-Cico, Dessa K.; Lape, Megan E.

2013-01-01

Background: Alcohol and marijuana are the most commonly used psychoactive substances; however, the sequencing and relationship between age of first use and continued current problematic use among college-bound emerging adults is not well understood. Methods: This is a cross-sectional study of current and historical alcohol and marijuana use among…

Behavior of a high-temperature superconducting conductor on a round core cable at current ramp rates as high as 67.8 kA s-1 in background fields of up to 19 T

NASA Astrophysics Data System (ADS)

Michael, P. C.; Bromberg, L.; van der Laan, D. C.; Noyes, P.; Weijers, H. W.

2016-04-01

High temperature superconducting (HTS) conductor-on-round-core (CORC®) cables have been developed for use in power transmission systems and large high-field magnets. The use of high-current conductors for large-scale magnets reduces system inductance and limits the peak voltage needed for ramped field operation. A CORC® cable contains a large number of RE-Ba2Cu3O7-δ (RE = rare earth) (REBCO) coated conductors, helically wound in multiple layers on a thin, round former. Large-scale applications, such as fusion and accelerator magnets, require current ramp rates of several kilo-Amperes per second during pulsed operation. This paper presents results that demonstrate the electromagnetic stability of a CORC® cable during transient conditions. Measurements were performed at 4.2 K using a 1.55 m long CORC® cable in background fields of up to 19 T. Repeated current pulses in a background field of 19 T at current ramp rates of up to 67.8 kA s-1 to approximately 90% of the cable’s quench current at that field, did not show any sign of degradation in cable performance due to excessive ac loss or electromagnetic instability. The very high current ramp rates applied during these tests were used to compensate, to the extent possible, the limited cable length accommodated by the test facility, assuming that the measured results could be extrapolated to longer length cables operated at proportionally lower current ramp rates. No shift of the superconducting transition to lower current was measured when the current ramp rate was increased from 25 A s-1 to 67.8 kA s-1. These results demonstrate the viability of CORC® cables for use in low-inductance magnets that operate at moderate to high current ramp rates.

Advanced practice registered nurses and physician assistants in sleep centers and clinics: a survey of current roles and educational background.

PubMed

Colvin, Loretta; Cartwright, Ann; Collop, Nancy; Freedman, Neil; McLeod, Don; Weaver, Terri E; Rogers, Ann E

2014-05-15

To survey Advanced Practice Registered Nurse (APRN) and Physician Assistant (PA) utilization, roles and educational background within the field of sleep medicine. Electronic surveys distributed to American Academy of Sleep Medicine (AASM) member centers and APRNs and PAs working within sleep centers and clinics. Approximately 40% of responding AASM sleep centers reported utilizing APRNs or PAs in predominantly clinical roles. Of the APRNs and PAs surveyed, 95% reported responsibilities in sleep disordered breathing and more than 50% in insomnia and movement disorders. Most APRNs and PAs were prepared at the graduate level (89%), with sleep-specific education primarily through "on the job" training (86%). All APRNs surveyed were Nurse Practitioners (NPs), with approximately double the number of NPs compared to PAs. APRNs and PAs were reported in sleep centers at proportions similar to national estimates of NPs and PAs in physicians' offices. They report predominantly clinical roles, involving common sleep disorders. Given current predictions that the outpatient healthcare structure will change and the number of APRNs and PAs will increase, understanding the role and utilization of these professionals is necessary to plan for the future care of patients with sleep disorders. Surveyed APRNs and PAs reported a significant deficiency in formal and standardized sleep-specific education. Efforts to provide formal and standardized educational opportunities for APRNs and PAs that focus on their clinical roles within sleep centers could help fill a current educational gap.

Sensitivity curves for searches for gravitational-wave backgrounds

NASA Astrophysics Data System (ADS)

Thrane, Eric; Romano, Joseph D.

2013-12-01

We propose a graphical representation of detector sensitivity curves for stochastic gravitational-wave backgrounds that takes into account the increase in sensitivity that comes from integrating over frequency in addition to integrating over time. This method is valid for backgrounds that have a power-law spectrum in the analysis band. We call these graphs “power-law integrated curves.” For simplicity, we consider cross-correlation searches for unpolarized and isotropic stochastic backgrounds using two or more detectors. We apply our method to construct power-law integrated sensitivity curves for second-generation ground-based detectors such as Advanced LIGO, space-based detectors such as LISA and the Big Bang Observer, and timing residuals from a pulsar timing array. The code used to produce these plots is available at https://dcc.ligo.org/LIGO-P1300115/public for researchers interested in constructing similar sensitivity curves.

The projected background for the CUORE experiment

DOE PAGES

Alduino, C.; Alfonso, K.; Artusa, D. R.; ...

2017-08-14

The Cryogenic Underground Observatory for Rare Events (CUORE) is designed to search for neutrinoless double beta decay of 130Te with an array of 988 TeO 2 bolometers operating at temperatures around 10 mK. The experiment is currently being commissioned in Hall A of Laboratori Nazionali del Gran Sasso, Italy. The goal of CUORE is to reach a 90% C.L. exclusion sensitivity on the 130Te decay half-life of 9 × 10 25 years after 5 years of data taking. The main issue to be addressed to accomplish this aim is the rate of background events in the region of interest, whichmore » must not be higher than 10 –2 counts/keV/kg/year. We developed a detailed Monte Carlo simulation, based on results from a campaign of material screening, radioassays, and bolometric measurements, to evaluate the expected background. This was used over the years to guide the construction strategies of the experiment and we use it here to project a background model for CUORE. In this paper we report the results of our study and our expectations for the background rate in the energy region where the peak signature of neutrinoless double beta decay of 130Te is expected.« less

The projected background for the CUORE experiment

NASA Astrophysics Data System (ADS)

Alduino, C.; Alfonso, K.; Artusa, D. R.; Avignone, F. T.; Azzolini, O.; Banks, T. I.; Bari, G.; Beeman, J. W.; Bellini, F.; Benato, G.; Bersani, A.; Biassoni, M.; Branca, A.; Brofferio, C.; Bucci, C.; Camacho, A.; Caminata, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Cappelli, L.; Carbone, L.; Cardani, L.; Carniti, P.; Casali, N.; Cassina, L.; Chiesa, D.; Chott, N.; Clemenza, M.; Copello, S.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Cushman, J. S.; D'Addabbo, A.; Dafinei, I.; Davis, C. J.; Dell'Oro, S.; Deninno, M. M.; Di Domizio, S.; Di Vacri, M. L.; Drobizhev, A.; Fang, D. Q.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Franceschi, M. A.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Gladstone, L.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Hansen, E.; Heeger, K. M.; Hennings-Yeomans, R.; Hickerson, K. P.; Huang, H. Z.; Kadel, R.; Keppel, G.; Kolomensky, Yu. G.; Leder, A.; Ligi, C.; Lim, K. E.; Ma, Y. G.; Maino, M.; Marini, L.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Moggi, N.; Morganti, S.; Mosteiro, P. J.; Napolitano, T.; Nastasi, M.; Nones, C.; Norman, E. B.; Novati, V.; Nucciotti, A.; O'Donnell, T.; Ouellet, J. L.; Pagliarone, C. E.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pira, C.; Pirro, S.; Pozzi, S.; Previtali, E.; Rosenfeld, C.; Rusconi, C.; Sakai, M.; Sangiorgio, S.; Santone, D.; Schmidt, B.; Schmidt, J.; Scielzo, N. D.; Singh, V.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tomei, C.; Trentalange, S.; Vignati, M.; Wagaarachchi, S. L.; Wang, B. S.; Wang, H. W.; Welliver, B.; Wilson, J.; Winslow, L. A.; Wise, T.; Woodcraft, A.; Zanotti, L.; Zhang, G. Q.; Zhu, B. X.; Zimmermann, S.; Zucchelli, S.; Laubenstein, M.

2017-08-01

The Cryogenic Underground Observatory for Rare Events (CUORE) is designed to search for neutrinoless double beta decay of ^{130}Te with an array of 988 TeO_2 bolometers operating at temperatures around 10 mK. The experiment is currently being commissioned in Hall A of Laboratori Nazionali del Gran Sasso, Italy. The goal of CUORE is to reach a 90% C.L. exclusion sensitivity on the ^{130}Te decay half-life of 9 × 10^{25} years after 5 years of data taking. The main issue to be addressed to accomplish this aim is the rate of background events in the region of interest, which must not be higher than 10^{-2} counts/keV/kg/year. We developed a detailed Monte Carlo simulation, based on results from a campaign of material screening, radioassays, and bolometric measurements, to evaluate the expected background. This was used over the years to guide the construction strategies of the experiment and we use it here to project a background model for CUORE. In this paper we report the results of our study and our expectations for the background rate in the energy region where the peak signature of neutrinoless double beta decay of ^{130}Te is expected.

Step-scan differential Fourier transform infrared photoacoustic spectroscopy (DFTIR-PAS): a spectral deconvolution method for weak absorber detection in the presence of strongly overlapping background absorptions.

PubMed

Liu, Lixian; Mandelis, Andreas; Huan, Huiting; Michaelian, Kirk H

2017-04-01

The determination of small absorption coefficients of trace gases in the atmosphere constitutes a challenge for analytical air contaminant measurements, especially in the presence of strongly absorbing backgrounds. A step-scan differential Fourier transform infrared photoacoustic spectroscopy (DFTIR-PAS) method was developed to suppress the coherent external noise and spurious photoacoustic (PA) signals caused by strongly absorbing backgrounds. The infrared absorption spectra of acetylene (C₂H₂) and local air were used to verify the performance of the step-scan DFTIR-PAS method. A linear amplitude response to C₂H₂ concentrations from 100 to 5000 ppmv was observed, leading to a theoretical detection limit of 5 ppmv. The differential mode was capable of eliminating the coherent noise and dominant background gas signals, thereby revealing the presence of the otherwise hidden C₂H₂ weak absorption. Thus, the step-scan DFTIR-PAS modality was demonstrated to be an effective approach for monitoring weakly absorbing gases with absorption bands overlapped by strongly absorbing background species.

Pleural manometry-historical background, rationale for use and methods of measurement.

PubMed

Zielinska-Krawczyk, Monika; Krenke, Rafal; Grabczak, Elzbieta M; Light, Richard W

2018-03-01

Subatmospheric pleural pressure (Ppl), which is approximately -3 to -5 cmH 2 O at functional residual capacity (FRC) makes pleura a unique organ in the human body. The negative Ppl is critical for maintaining the lungs in a properly inflated state and for proper blood circulation within the thorax. Significant and sudden pleural pressure changes associated with major pleural pathologies, as well as therapeutic interventions may be associated with life-threatening complications. The pleural pressure may show two different values depending on the measurement method applied. These are called pleural liquid pressure and pleural surface pressure. It should also be realized that there are significant differences in pleural pressure distribution in pneumothorax and pleural effusion. In pneumothorax, the pressure is the same throughout the pleural space, while in pleural effusion there is a vertical gradient of approximately 1 cm H 2 O/cm in the pleural pressure associated with the hydrostatic pressure of the fluid column. Currently, two main methods of pleural pressure measurement are used: simple water manometers and electronic systems. The water manometers are conceptually simple, cheap and user-friendly but they only allow the estimation of the mean values of pleural pressure. The electronic systems for pleural pressure measurement are based on pressure transducers. Their major advantages include precise measurements of instantaneous pleural pressure and the ability to display and to store a large amount of data. The paper presents principles and details of pleural pressure measurement as well as the rationale for its use. Copyright © 2018 Elsevier Ltd. All rights reserved.

Observable tensor-to-scalar ratio and secondary gravitational wave background

NASA Astrophysics Data System (ADS)

Chatterjee, Arindam; Mazumdar, Anupam

2018-03-01

In this paper we will highlight how a simple vacuum energy dominated inflection-point inflation can match the current data from cosmic microwave background radiation, and predict large primordial tensor to scalar ratio, r ˜O (10-3-10-2), with observable second order gravitational wave background, which can be potentially detectable from future experiments, such as DECi-hertz Interferometer Gravitational wave Observatory (DECIGO), Laser Interferometer Space Antenna (eLISA), cosmic explorer (CE), and big bang observatory (BBO).

Can one measure the Cosmic Neutrino Background?

NASA Astrophysics Data System (ADS)

Faessler, Amand; Hodák, Rastislav; Kovalenko, Sergey; Šimkovic, Fedor

The Cosmic Microwave Background (CMB) yields information about our Universe at around 380,000 years after the Big Bang (BB). Due to the weak interaction of the neutrinos with matter, the Cosmic Neutrino Background (CNB) should give information about a much earlier time of our Universe, around one second after the BB. Probably, the most promising method to “see” the CNB is the capture of the electron neutrinos from the Background by Tritium, which then decays into 3He and an electron with the energy of the the Q-value = 18.562keV plus the electron neutrino rest mass. The “KArlsruhe TRItium Neutrino” (KATRIN) experiment, which is in preparation, seems presently the most sensitive proposed method for measuring the electron antineutrino mass. At the same time, KATRIN can also look by the reaction νe(˜ 1.95K) +3H →3He + e-(Q = 18.6keV + m νec2). The capture of the Cosmic Background Neutrinos (CNB) should show in the electron spectrum as a peak by the electron neutrino rest mass above Q. Here, the possibility to see the CNB with KATRIN is studied. A detection of the CNB by KATRIN seems not to be possible at the moment. But KATRIN should be able to determine an upper limit for the local electron neutrino density of the CNB.

Can one measure the Cosmic Neutrino Background?

NASA Astrophysics Data System (ADS)

Faessler, Amand; Hodák, Rastislav; Kovalenko, Sergey; Šimkovic, Fedor

The Cosmic Microwave Background (CMB) yields information about our Universe at around 380,000 years after the Big Bang (BB). Due to the weak interaction of the neutrinos with matter, the Cosmic Neutrino Background (CNB) should give information about a much earlier time of our Universe, around one second after the BB. Probably, the most promising method to "see" the CNB is the capture of the electron neutrinos from the Background by Tritium, which then decays into 3He and an electron with the energy of the the Q-value = 18.562 keV plus the electron neutrino rest mass. The "KArlsruhe TRItium Neutrino" (KATRIN) experiment, which is in preparation, seems presently the most sensitive proposed method for measuring the electron antineutrino mass. At the same time, KATRIN can also look by the reaction νe(˜1.95K) + 3H → 3He + e-(Q = 18.6keV + mνec2). The capture of the Cosmic Background Neutrinos (CNB) should show in the electron spectrum as a peak by the electron neutrino rest mass above Q. Here, the possibility to see the CNB with KATRIN is studied. A detection of the CNB by KATRIN seems not to be possible at the moment. But KATRIN should be able to determine an upper limit for the local electron neutrino density of the CNB.

Methods for Addressing Technology-Induced Errors: The Current State

PubMed Central

Dexheimer, J. W.; Hullin Lucay Cossio, C.; Gong, Y.; Jensen, S.; Kaipio, J.; Kennebeck, S.; Kirkendall, E.; Kushniruk, A. W.; Kuziemsky, C.; Marcilly, R.; Röhrig, R.; Saranto, K.; Senathirajah, Y.; Weber, J.; Takeda, H.

2016-01-01

Summary Objectives The objectives of this paper are to review and discuss the methods that are being used internationally to report on, mitigate, and eliminate technology-induced errors. Methods The IMIA Working Group for Health Informatics for Patient Safety worked together to review and synthesize some of the main methods and approaches associated with technology-induced error reporting, reduction, and mitigation. The work involved a review of the evidence-based literature as well as guideline publications specific to health informatics. Results The paper presents a rich overview of current approaches, issues, and methods associated with: (1) safe HIT design, (2) safe HIT implementation, (3) reporting on technology-induced errors, (4) technology-induced error analysis, and (5) health information technology (HIT) risk management. The work is based on research from around the world. Conclusions Internationally, researchers have been developing methods that can be used to identify, report on, mitigate, and eliminate technology-induced errors. Although there remain issues and challenges associated with the methodologies, they have been shown to improve the quality and safety of HIT. Since the first publications documenting technology-induced errors in healthcare in 2005, we have seen in a short 10 years researchers develop ways of identifying and addressing these types of errors. We have also seen organizations begin to use these approaches. Knowledge has been translated into practice in a short ten years whereas the norm for other research areas is of 20 years. PMID:27830228

Effect of Background Pressure on the Performance and Plume of the HiVHAc Hall Thruster

NASA Technical Reports Server (NTRS)

Huang, Wensheng; Kamhawi, Hani; Haag, Thomas

2013-01-01

During the Single String Integration Test of the NASA HiVHAc Hall thruster, a number of plasma diagnostics were implemented to study the effect of varying facility background pressure on thruster operation. These diagnostics include thrust stand, Faraday probe, ExB probe, and retarding potential analyzer. The test results indicated a rise in thrust and discharge current with background pressure. There was also a decrease in ion energy per charge, an increase in multiply-charged species production, a decrease in plume divergence, and a decrease in ion beam current with increasing background pressure. A simplified ingestion model was applied to determine the maximum acceptable background pressure for thrust measurement. The maximum acceptable ingestion percentage was found to be around 1%. Examination of the diagnostics results suggest the ionization and acceleration zones of the thruster were shifting upstream with increasing background pressure.

Radiation detection method and system using the sequential probability ratio test

DOEpatents

Nelson, Karl E [Livermore, CA; Valentine, John D [Redwood City, CA; Beauchamp, Brock R [San Ramon, CA

2007-07-17

A method and system using the Sequential Probability Ratio Test to enhance the detection of an elevated level of radiation, by determining whether a set of observations are consistent with a specified model within a given bounds of statistical significance. In particular, the SPRT is used in the present invention to maximize the range of detection, by providing processing mechanisms for estimating the dynamic background radiation, adjusting the models to reflect the amount of background knowledge at the current point in time, analyzing the current sample using the models to determine statistical significance, and determining when the sample has returned to the expected background conditions.

Magnetic force microscopy method and apparatus to detect and image currents in integrated circuits

DOEpatents

Campbell, Ann. N.; Anderson, Richard E.; Cole, Jr., Edward I.

1995-01-01

A magnetic force microscopy method and improved magnetic tip for detecting and quantifying internal magnetic fields resulting from current of integrated circuits. Detection of the current is used for failure analysis, design verification, and model validation. The interaction of the current on the integrated chip with a magnetic field can be detected using a cantilevered magnetic tip. Enhanced sensitivity for both ac and dc current and voltage detection is achieved with voltage by an ac coupling or a heterodyne technique. The techniques can be used to extract information from analog circuits.

Magnetic force microscopy method and apparatus to detect and image currents in integrated circuits

DOEpatents

Campbell, A.N.; Anderson, R.E.; Cole, E.I. Jr.

1995-11-07

A magnetic force microscopy method and improved magnetic tip for detecting and quantifying internal magnetic fields resulting from current of integrated circuits are disclosed. Detection of the current is used for failure analysis, design verification, and model validation. The interaction of the current on the integrated chip with a magnetic field can be detected using a cantilevered magnetic tip. Enhanced sensitivity for both ac and dc current and voltage detection is achieved with voltage by an ac coupling or a heterodyne technique. The techniques can be used to extract information from analog circuits. 17 figs.

The Radio Synchrotron Background: Conference Summary and Report

NASA Astrophysics Data System (ADS)

Singal, J.; Haider, J.; Ajello, M.; Ballantyne, D. R.; Bunn, E.; Condon, J.; Dowell, J.; Fixsen, D.; Fornengo, N.; Harms, B.; Holder, G.; Jones, E.; Kellermann, K.; Kogut, A.; Linden, T.; Monsalve, R.; Mertsch, P.; Murphy, E.; Orlando, E.; Regis, M.; Scott, D.; Vernstrom, T.; Xu, L.

2018-03-01

We summarize the radio synchrotron background workshop that took place 2017 July 19–21 at the University of Richmond. This first scientific meeting dedicated to the topic was convened because current measurements of the diffuse radio monopole reveal a surface brightness that is several times higher than can be straightforwardly explained by known Galactic and extragalactic sources and processes, rendering it by far the least well understood photon background at present. It was the conclusion of a majority of the participants that the radio monopole level is at or near that reported by the ARCADE 2 experiment and inferred from several absolutely calibrated zero-level lower frequency radio measurements, and unanimously agreed that the production of this level of surface brightness, if confirmed, represents a major outstanding question in astrophysics. The workshop reached a consensus on the next priorities for investigations of the radio synchrotron background.

Background Noise Reduction Using Adaptive Noise Cancellation Determined by the Cross-Correlation

NASA Technical Reports Server (NTRS)

Spalt, Taylor B.; Brooks, Thomas F.; Fuller, Christopher R.

2012-01-01

Background noise due to flow in wind tunnels contaminates desired data by decreasing the Signal-to-Noise Ratio. The use of Adaptive Noise Cancellation to remove background noise at measurement microphones is compromised when the reference sensor measures both background and desired noise. The technique proposed modifies the classical processing configuration based on the cross-correlation between the reference and primary microphone. Background noise attenuation is achieved using a cross-correlation sample width that encompasses only the background noise and a matched delay for the adaptive processing. A present limitation of the method is that a minimum time delay between the background noise and desired signal must exist in order for the correlated parts of the desired signal to be separated from the background noise in the crosscorrelation. A simulation yields primary signal recovery which can be predicted from the coherence of the background noise between the channels. Results are compared with two existing methods.

A comparative study of new and current methods for dental micro-CT image denoising

PubMed Central

Lashgari, Mojtaba; Qin, Jie; Swain, Michael

2016-01-01

Objectives: The aim of the current study was to evaluate the application of two advanced noise-reduction algorithms for dental micro-CT images and to implement a comparative analysis of the performance of new and current denoising algorithms. Methods: Denoising was performed using gaussian and median filters as the current filtering approaches and the block-matching and three-dimensional (BM3D) method and total variation method as the proposed new filtering techniques. The performance of the denoising methods was evaluated quantitatively using contrast-to-noise ratio (CNR), edge preserving index (EPI) and blurring indexes, as well as qualitatively using the double-stimulus continuous quality scale procedure. Results: The BM3D method had the best performance with regard to preservation of fine textural features (CNREdge), non-blurring of the whole image (blurring index), the clinical visual score in images with very fine features and the overall visual score for all types of images. On the other hand, the total variation method provided the best results with regard to smoothing of images in texture-free areas (CNRTex-free) and in preserving the edges and borders of image features (EPI). Conclusions: The BM3D method is the most reliable technique for denoising dental micro-CT images with very fine textural details, such as shallow enamel lesions, in which the preservation of the texture and fine features is of the greatest importance. On the other hand, the total variation method is the technique of choice for denoising images without very fine textural details in which the clinician or researcher is interested mainly in anatomical features and structural measurements. PMID:26764583

Background rejection in NEXT using deep neural networks

DOE PAGES

Renner, J.; Farbin, A.; Vidal, J. Muñoz; ...

2017-01-16

Here, we investigate the potential of using deep learning techniques to reject background events in searches for neutrinoless double beta decay with high pressure xenon time projection chambers capable of detailed track reconstruction. The differences in the topological signatures of background and signal events can be learned by deep neural networks via training over many thousands of events. These networks can then be used to classify further events as signal or background, providing an additional background rejection factor at an acceptable loss of efficiency. The networks trained in this study performed better than previous methods developed based on the usemore » of the same topological signatures by a factor of 1.2 to 1.6, and there is potential for further improvement.« less

Time-gated flow cytometry: an ultra-high selectivity method to recover ultra-rare-event μ-targets in high-background biosamples

NASA Astrophysics Data System (ADS)

Jin, Dayong; Piper, James A.; Leif, Robert C.; Yang, Sean; Ferrari, Belinda C.; Yuan, Jingli; Wang, Guilan; Vallarino, Lidia M.; Williams, John W.

2009-03-01

A fundamental problem for rare-event cell analysis is auto-fluorescence from nontarget particles and cells. Time-gated flow cytometry is based on the temporal-domain discrimination of long-lifetime (>1 μs) luminescence-stained cells and can render invisible all nontarget cell and particles. We aim to further evaluate the technique, focusing on detection of ultra-rare-event 5-μm calibration beads in environmental water dirt samples. Europium-labeled 5-μm calibration beads with improved luminescence homogeneity and reduced aggregation were evaluated using the prototype UV LED excited time-gated luminescence (TGL) flow cytometer (FCM). A BD FACSAria flow cytometer was used to sort accurately a very low number of beads (<100 events), which were then spiked into concentrated samples of environmental water. The use of europium-labeled beads permitted the demonstration of specific detection rates of 100%+/-30% and 91%+/-3% with 10 and 100 target beads, respectively, that were mixed with over one million nontarget autofluorescent background particles. Under the same conditions, a conventional FCM was unable to recover rare-event fluorescein isothiocyanate (FITC) calibration beads. Preliminary results on Giardia detection are also reported. We have demonstrated the scientific value of lanthanide-complex biolabels in flow cytometry. This approach may augment the current method that uses multifluorescence-channel flow cytometry gating.

Effects of placement point of background music on shopping website.

PubMed

Lai, Chien-Jung; Chiang, Chia-Chi

2012-01-01

Consumer on-line behaviors are more important than ever due to highly growth of on-line shopping. The purposes of this study were to design placement methods of background music for shopping website and examine the effect on browsers' emotional and cognitive response. Three placement points of background music during the browsing, i.e. 2 min., 4 min., and 6 min. from the start of browsing were considered for entry points. Both browsing without music (no music) and browsing with constant music volume (full music) were treated as control groups. Participants' emotional state, approach-avoidance behavior intention, and action to adjust music volume were collected. Results showed that participants had a higher level of pleasure, arousal and approach behavior intention for the three placement points than for no music and full music. Most of the participants for full music (5/6) adjusted the background music. Only 16.7% (3/18) participants for other levels turn off the background music. The results indicate that playing background music after the start of browsing is benefit for on-line shopping atmosphere. It is inappropriate to place background music at the start of browsing shopping website. The marketer must manipulated placement methods of background music for a web store carefully.

Application of Research on the Metallogenic Background in the Assessment of Mineral Resources Potentiality

NASA Astrophysics Data System (ADS)

Jia, D.; Feng, Y.; Liu, J.; Yao, X.; Zhang, Z.; Ye, T.

2017-12-01

1. Working BackgroundCurrent Status of Geological Prospecting: Detecting boundaries and bottoms, making ore search nearby; Seeing the stars, not seeing the Moon; Deep prospecting, undesirable results. The reasons of these problems are the regional metallogenic backgroud unclear and the metallogenic backgroud of the exploration regions unknown. Accordingly, Development and Research Center, CGS organized a geological setting research, in detail investigate metallogenic geological features and acquire mineralization information. 2. Technical SchemeCore research content is prediction elements of Metallogenic Structure. Adopt unified technical requirements from top to bottom, and technical route from bottom to top; Divide elements of mineral forecast and characteristics of geological structure into five elements for research and expression; Make full use of geophysical, geochemical and remote sensing inferences for the interpretation of macro information. After eight years the great project was completed. 3. Main AchievementsInnovation of basic maps compilation content of geological background, reinforce of geological structure data base of potentiality valuation. Preparation of geotectonic facies maps in different scales and professions, providing brand-new geologic background for potentiality assessment, promoting Chinese geotectonic research to the new height. Preparation of 3,375 geological structure thematic base maps of detecting working area in 6 kinds of prediction methods, providing base working maps, rock assemblage, structure of the protolith of geologic body / mineralization / ore controlling for mineral prediction of 25 ores. Enrichment and development of geotectonic facies analysis method, establishment of metallogenic background research thoughts and approach system for assessment of national mineral resources potentiality for the first time. 4. Application EffectOrientation——More and better results with less effort. Positioning——Have a definite

Tanzania: Background and Current Conditions

DTIC Science & Technology

2010-12-08

movement of refugees. Societal violence against women and persons with albinism and women persisted. Female genital mutilation (FGM), especially of...Zanzibar /islands over 99% Muslim Literacy: Male, 77.5%; Female , 66.2% (2003) Under-5 Mortality: 165 deaths/1,000 live births HIV/AIDS adult...infection rate: 6.2% (2007) Life Expectancy, years at birth: Male, 50.5 Female , 53.5 (2009 est.) Sources: CIA World Factbook 2010. Tanzania

Tanzania: Background and Current Conditions

DTIC Science & Technology

2010-07-23

persons with albinism and women persisted. Female genital mutilation (FGM), especially of young girls, continued to be practiced. Trafficking in...35%; Zanzibar /islands over 99% Muslim Literacy: Male, 77.5%; Female , 66.2% (2003) Under-5 Mortality: 165 deaths/1,000 live births HIV/AIDS adult...infection rate: 6.2% (2007) Life Expectancy, years at birth: Male, 50.5 Female , 53.5 (2009 est.) Sources: CIA World Factbook 2010. Tanzania

[Development and current situation of reconstruction methods following total sacrectomy].

PubMed

Huang, Siyi; Ji, Tao; Guo, Wei

2018-05-01

To review the development of the reconstruction methods following total sacrectomy, and to provide reference for finding a better reconstruction method following total sacrectomy. The case reports and biomechanical and finite element studies of reconstruction following total sacrectomy at home and abroad were searched. Development and current situation were summarized. After developing for nearly 30 years, great progress has been made in the reconstruction concept and fixation techniques. The fixation methods can be summarized as the following three strategies: spinopelvic fixation (SPF), posterior pelvic ring fixation (PPRF), and anterior spinal column fixation (ASCF). SPF has undergone technical progress from intrapelvic rod and hook constructs to pedicle and iliac screw-rod systems. PPRF and ASCF could improve the stability of the reconstruction system. Reconstruction following total sacrectomy remains a challenge. Reconstruction combining SPF, PPRF, and ASCF is the developmental direction to achieve mechanical stability. How to gain biological fixation to improve the long-term stability is an urgent problem to be solved.

Background characterization of an ultra-low background liquid scintillation counter

DOE PAGES

Erchinger, J. L.; Orrell, John L.; Aalseth, C. E.; ...

2017-01-26

The Ultra-Low Background Liquid Scintillation Counter developed by Pacific Northwest National Laboratory will expand the application of liquid scintillation counting by enabling lower detection limits and smaller sample volumes. By reducing the overall count rate of the background environment approximately 2 orders of magnitude below that of commercially available systems, backgrounds on the order of tens of counts per day over an energy range of ~3–3600 keV can be realized. Finally, initial test results of the ULB LSC show promising results for ultra-low background detection with liquid scintillation counting.

Seasonal changes in background levels of deuterium and oxygen-18 prove water drinking by harp seals, which affects the use of the doubly labelled water method.

PubMed

Nordøy, Erling S; Lager, Anne R; Schots, Pauke C

2017-12-01

The aim of this study was to monitor seasonal changes in stable isotopes of pool freshwater and harp seal ( Phoca groenlandica ) body water, and to study whether these potential seasonal changes might bias results obtained using the doubly labelled water (DLW) method when measuring energy expenditure in animals with access to freshwater. Seasonal changes in the background levels of deuterium and oxygen-18 in the body water of four captive harp seals and in the freshwater pool in which they were kept were measured over a time period of 1 year. The seals were offered daily amounts of capelin and kept under a seasonal photoperiod of 69°N. Large seasonal variations of deuterium and oxygen-18 in the pool water were measured, and the isotope abundance in the body water showed similar seasonal changes to the pool water. This shows that the seals were continuously equilibrating with the surrounding water as a result of significant daily water drinking. Variations in background levels of deuterium and oxygen-18 in freshwater sources may be due to seasonal changes in physical processes such as precipitation and evaporation that cause fractionation of isotopes. Rapid and abrupt changes in the background levels of deuterium and oxygen-18 may complicate calculation of energy expenditure by use of the DLW method. It is therefore strongly recommended that analysis of seasonal changes in background levels of isotopes is performed before the DLW method is applied on (free-ranging) animals, and to use a control group in order to correct for changes in background levels. © 2017. Published by The Company of Biologists Ltd.

Associations of Trying to Lose Weight, Weight Control Behaviors, and Current Cigarette Use among US High School Students

ERIC Educational Resources Information Center

Johnson, Jonetta L.; Eaton, Danice K.; Pederson, Linda L.; Lowry, Richard

2009-01-01

Background: Approximately one-quarter of high school students currently use cigarettes. Previous research has suggested some youth use smoking as a method for losing weight. The purpose of this study was to describe the association of current cigarette use with specific healthy and unhealthy weight control practices among 9th-12th grade students…

Background noise analysis in urban airport surroundings of Brazilian cities, Congonhas Airport, São Paulo

PubMed Central

Scatolini, Fabio; Alves, Cláudio Jorge Pinto

2016-01-01

ABSTRACT OBJECTIVE To perform a quantitative analysis of the background noise at Congonhas Airport surroundings based on large sampling and measurements with no interruption. METHODS Measuring sites were chosen from 62 and 72 DNL (day-night-level) noise contours, in urban sites compatible with residential use. Fifteen sites were monitored for at least 168 hours without interruption or seven consecutive days. Data compilation was based on cross-reference between noise measurements and air traffic control records, and results were validated by airport meteorological reports. Preliminary diagnoses were established using the standard NBR-13368. Background noise values were calculated based on the Sound Exposure Level (SEL). Statistic parameters were calculated in one-hour intervals. RESULTS Only four of the fifteen sites assessed presented aircraft operations as a clear cause for the noise annoyance. Even so, it is possible to detect background noise levels above regulation limits during periods of low airport activity or when it closes at night. CONCLUSIONS All the sites monitored showed background noise levels above regulation limits between 7:00 and 21:00. In the intervals between 6:00-6:59 and 21:00-22:59 the noise data, when analyzed with the current airport operational characteristics, still allow the development of additional mitigating measures. PMID:28099658

Current Evaluation of Upper Oesophageal Sphincter Opening in Dysphagia Practice: An International SLT Survey

ERIC Educational Resources Information Center

Regan, Julie; Walshe, Margaret; McMahon, Barry P.

2012-01-01

Background: The assessment of adequate upper oesophageal sphincter (UOS) opening during swallowing is an integral component of dysphagia evaluation. Aims: To ascertain speech and language therapists' (SLTs) satisfaction with current methods for assessing UOS function in people with dysphagia and to identify challenges encountered by SLTs with UOS…

Correlated perturbations from inflation and the cosmic microwave background.

PubMed

Amendola, Luca; Gordon, Christopher; Wands, David; Sasaki, Misao

2002-05-27

We compare the latest cosmic microwave background data with theoretical predictions including correlated adiabatic and cold dark matter (CDM) isocurvature perturbations with a simple power-law dependence. We find that there is a degeneracy between the amplitude of correlated isocurvature perturbations and the spectral tilt. A negative (red) tilt is found to be compatible with a larger isocurvature contribution. Estimates of the baryon and CDM densities are found to be almost independent of the isocurvature amplitude. The main result is that current microwave background data do not exclude a dominant contribution from CDM isocurvature fluctuations on large scales.

Background Oriented Schlieren Using Celestial Objects

NASA Technical Reports Server (NTRS)

Haering, Edward, A., Jr. (Inventor); Hill, Michael A (Inventor)

2017-01-01

The present invention is a system and method of visualizing fluid flow around an object, such as an aircraft or wind turbine, by aligning the object between an imaging system and a celestial object having a speckled background, taking images, and comparing those images to obtain fluid flow visualization.

Analytical evaluation of current starch methods used in the international sugar industry: Part I

USDA-ARS?s Scientific Manuscript database

Several analytical starch methods currently exist in the international sugar industry that are used to prevent or mitigate starch-related processing challenges as well as assess the quality of traded end-products. These methods use simple iodometric chemistry, mostly potato starch standards, and uti...

Particle production in a gravitational wave background

NASA Astrophysics Data System (ADS)

Jones, Preston; McDougall, Patrick; Singleton, Douglas

2017-03-01

We study the possibility that massless particles, such as photons, are produced by a gravitational wave. That such a process should occur is implied by tree-level Feynman diagrams such as two gravitons turning into two photons, i.e., g +g →γ +γ . Here we calculate the rate at which a gravitational wave creates a massless scalar field. This is done by placing the scalar field in the background of a plane gravitational wave and calculating the 4-current of the scalar field. Even in the vacuum limit of the scalar field it has a nonzero vacuum expectation value (similar to what occurs in the Higgs mechanism) and a nonzero current. We associate this with the production of scalar field quanta by the gravitational field. This effect has potential consequences for the attenuation of gravitational waves since the massless field is being produced at the expense of the gravitational field. This is related to the time-dependent Schwinger effect, but with the electric field replaced by the gravitational wave background and the electron/positron field quanta replaced by massless scalar "photons." Since the produced scalar quanta are massless there is no exponential suppression, as occurs in the Schwinger effect due to the electron mass.

Mathematical background of Parrondo's paradox

NASA Astrophysics Data System (ADS)

Behrends, Ehrhard

2004-05-01

Parrondo's paradox states that there are losing gambling games which, when being combined stochastically or in a suitable deterministic way, give rise to winning games. Here we investigate the probabilistic background. We show how the properties of the equilibrium distributions of the Markov chains under consideration give rise to the paradoxical behavior, and we provide methods how to find the best a priori strategies.

Background oriented schlieren in a density stratified fluid.

PubMed

Verso, Lilly; Liberzon, Alex

2015-10-01

Non-intrusive quantitative fluid density measurement methods are essential in the stratified flow experiments. Digital imaging leads to synthetic schlieren methods in which the variations of the index of refraction are reconstructed computationally. In this study, an extension to one of these methods, called background oriented schlieren, is proposed. The extension enables an accurate reconstruction of the density field in stratified liquid experiments. Typically, the experiments are performed by the light source, background pattern, and the camera positioned on the opposite sides of a transparent vessel. The multimedia imaging through air-glass-water-glass-air leads to an additional aberration that destroys the reconstruction. A two-step calibration and image remapping transform are the key components that correct the images through the stratified media and provide a non-intrusive full-field density measurements of transparent liquids.

Readout circuit with novel background suppression for long wavelength infrared focal plane arrays

NASA Astrophysics Data System (ADS)

Xie, L.; Xia, X. J.; Zhou, Y. F.; Wen, Y.; Sun, W. F.; Shi, L. X.

2011-02-01

In this article, a novel pixel readout circuit using a switched-capacitor integrator mode background suppression technique is presented for long wavelength infrared focal plane arrays. This circuit can improve dynamic range and signal-to-noise ratio by suppressing the large background current during integration. Compared with other background suppression techniques, the new background suppression technique is less sensitive to the process mismatch and has no additional shot noise. The proposed circuit is theoretically analysed and simulated while taking into account the non-ideal characteristics. The result shows that the background suppression non-uniformity is ultra-low even for a large process mismatch. The background suppression non-uniformity of the proposed circuit can also remain very small with technology scaling.

Methods for Addressing Technology-induced Errors: The Current State.

PubMed

Borycki, E; Dexheimer, J W; Hullin Lucay Cossio, C; Gong, Y; Jensen, S; Kaipio, J; Kennebeck, S; Kirkendall, E; Kushniruk, A W; Kuziemsky, C; Marcilly, R; Röhrig, R; Saranto, K; Senathirajah, Y; Weber, J; Takeda, H

2016-11-10

The objectives of this paper are to review and discuss the methods that are being used internationally to report on, mitigate, and eliminate technology-induced errors. The IMIA Working Group for Health Informatics for Patient Safety worked together to review and synthesize some of the main methods and approaches associated with technology- induced error reporting, reduction, and mitigation. The work involved a review of the evidence-based literature as well as guideline publications specific to health informatics. The paper presents a rich overview of current approaches, issues, and methods associated with: (1) safe HIT design, (2) safe HIT implementation, (3) reporting on technology-induced errors, (4) technology-induced error analysis, and (5) health information technology (HIT) risk management. The work is based on research from around the world. Internationally, researchers have been developing methods that can be used to identify, report on, mitigate, and eliminate technology-induced errors. Although there remain issues and challenges associated with the methodologies, they have been shown to improve the quality and safety of HIT. Since the first publications documenting technology-induced errors in healthcare in 2005, we have seen in a short 10 years researchers develop ways of identifying and addressing these types of errors. We have also seen organizations begin to use these approaches. Knowledge has been translated into practice in a short ten years whereas the norm for other research areas is of 20 years.

An Improved Distributed Secondary Control Method for DC Microgrids With Enhanced Dynamic Current Sharing Performance

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

Wang, Panbao; Lu, Xiaonan; Yang, Xu

This paper proposes an improved distributed secondary control scheme for dc microgrids (MGs), aiming at overcoming the drawbacks of conventional droop control method. The proposed secondary control scheme can remove the dc voltage deviation and improve the current sharing accuracy by using voltage-shifting and slope-adjusting approaches simultaneously. Meanwhile, the average value of droop coefficients is calculated, and then it is controlled by an additional controller included in the distributed secondary control layer to ensure that each droop coefficient converges at a reasonable value. Hence, by adjusting the droop coefficient, each participating converter has equal output impedance, and the accurate proportionalmore » load current sharing can be achieved with different line resistances. Furthermore, the current sharing performance in steady and transient states can be enhanced by using the proposed method. The effectiveness of the proposed method is verified by detailed experimental tests based on a 3 × 1 kW prototype with three interface converters.« less

Enhancements to the MCNP6 background source

DOE PAGES

McMath, Garrett E.; McKinney, Gregg W.

2015-10-19

The particle transport code MCNP has been used to produce a background radiation data file on a worldwide grid that can easily be sampled as a source in the code. Location-dependent cosmic showers were modeled by Monte Carlo methods to produce the resulting neutron and photon background flux at 2054 locations around Earth. An improved galactic-cosmic-ray feature was used to model the source term as well as data from multiple sources to model the transport environment through atmosphere, soil, and seawater. A new elevation scaling feature was also added to the code to increase the accuracy of the cosmic neutronmore » background for user locations with off-grid elevations. Furthermore, benchmarking has shown the neutron integral flux values to be within experimental error.« less

Effect of Listeners' Linguistic Background on Perceptual Judgements of Hypernasality

ERIC Educational Resources Information Center

Lee, Alice; Brown, Susanna; Gibbon, Fiona E.

2008-01-01

Background: Many speech and language therapists work in a multilingual environment, making cross-linguistic studies of speech disorders clinically and theoretically important. Aims: To investigate the effect of listeners' linguistic background on their perceptual ratings of hypernasality and the reliability of the ratings. Methods &…

Center background shows two fortyhorsepower directcurrent electric motors installed in ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Center background shows two forty-horsepower direct-current electric motors installed in 1904 to provide power to two drive shafts for first floor machine shops. - Thomas A. Edison Laboratories, Building No. 5, Main Street & Lakeside Avenue, West Orange, Essex County, NJ

Reduced background autofluorescence for cell imaging using nanodiamonds and lanthanide chelates.

PubMed

Cordina, Nicole M; Sayyadi, Nima; Parker, Lindsay M; Everest-Dass, Arun; Brown, Louise J; Packer, Nicolle H

2018-03-14

Bio-imaging is a key technique in tracking and monitoring important biological processes and fundamental biomolecular interactions, however the interference of background autofluorescence with targeted fluorophores is problematic for many bio-imaging applications. This study reports on two novel methods for reducing interference with cellular autofluorescence for bio-imaging. The first method uses fluorescent nanodiamonds (FNDs), containing nitrogen vacancy centers. FNDs emit at near-infrared wavelengths typically higher than most cellular autofluorescence; and when appropriately functionalized, can be used for background-free imaging of targeted biomolecules. The second method uses europium-chelating tags with long fluorescence lifetimes. These europium-chelating tags enhance background-free imaging due to the short fluorescent lifetimes of cellular autofluorescence. In this study, we used both methods to target E-selectin, a transmembrane glycoprotein that is activated by inflammation, to demonstrate background-free fluorescent staining in fixed endothelial cells. Our findings indicate that both FND and Europium based staining can improve fluorescent bio-imaging capabilities by reducing competition with cellular autofluorescence. 30 nm nanodiamonds coated with the E-selectin antibody was found to enable the most sensitive detective of E-selectin in inflamed cells, with a 40-fold increase in intensity detected.

To BG or not to BG: Background Subtraction for EIT Coronal Loops

NASA Astrophysics Data System (ADS)

Beene, J. E.; Schmelz, J. T.

2003-05-01

One of the few observational tests for various coronal heating models is to determine the temperature profile along coronal loops. Since loops are such an abundant coronal feature, this method originally seemed quite promising - that the coronal heating problem might actually be solved by determining the temperature as a function of arc length and comparing these observations with predictions made by different models. But there are many instruments currently available to study loops, as well as various techniques used to determine their temperature characteristics. Consequently, there are many different, mostly conflicting temperature results. We chose data for ten coronal loops observed with the Extreme ultraviolet Imaging Telescope (EIT), and chose specific pixels along each loop, as well as corresponding nearby background pixels where the loop emission was not present. Temperature analysis from the 171-to-195 and 195-to-284 angstrom image ratios was then performed on three forms of the data: the original data alone, the original data with a uniform background subtraction, and the original data with a pixel-by-pixel background subtraction. The original results show loops of constant temperature, as other authors have found before us, but the 171-to-195 and 195-to-284 results are significantly different. Background subtraction does not change the constant-temperature result or the value of the temperature itself. This does not mean that loops are isothermal, however, because the background pixels, which are not part of any contiguous structure, also produce a constant-temperature result with the same value as the loop pixels. These results indicate that EIT temperature analysis should not be trusted, and the isothermal loops that result from EIT (and TRACE) analysis may be an artifact of the analysis process. Solar physics research at the University of Memphis is supported by NASA grants NAG5-9783 and NAG5-12096.

[The German program for disease management guidelines. Background, methods, and development process].

PubMed

Ollenschläger, Günter; Kopp, Ina; Lelgemann, Monika; Sänger, Sylvia; Heymans, Lothar; Thole, Henning; Trapp, Henrike; Lorenz, Wilfried; Selbmann, Hans-Konrad; Encke, Albrecht

2006-10-15

The Program for National Disease Management Guidelines (German DM-CPG Program) was established in 2002 by the German Medical Association (umbrella organization of the German Chambers of Physicians) and joined by the Association of the Scientific Medical Societies (AWMF; umbrella organization of more than 150 professional societies) and by the National Association of Statutory Health Insurance Physicians (NASHIP) in 2003. The program provides a conceptual basis for disease management, focusing on high-priority health-care topics and aiming at the implementation of best practice recommendations for prevention, acute care, rehabilitation and chronic care. It is organized by the German Agency for Quality in Medicine, a founding member of the Guidelines International Network (G-I-N). The main objective of the German DM-CPG Program is to establish consensus of the medical professions on evidence-based key recommendations covering all sectors of health-care provision and facilitating the coordination of care for the individual patient through time and across interfaces. Within the last year, DM-CPGs have been published for asthma, chronic obstructive pulmonary disease, type 2 diabetes, and coronary heart disease. In addition, experts from national patient self-help groups have been developing patient guidance based upon the recommendations for health-care providers. The article describes background, methods, and tools of the DM-CPG Program, and is the first of a publication series dealing with innovative recommendations and aspects of the program.

Failure Detecting Method of Fault Current Limiter System with Rectifier

NASA Astrophysics Data System (ADS)

Tokuda, Noriaki; Matsubara, Yoshio; Asano, Masakuni; Ohkuma, Takeshi; Sato, Yoshibumi; Takahashi, Yoshihisa

A fault current limiter (FCL) is extensively needed to suppress fault current, particularly required for trunk power systems connecting high-voltage transmission lines, such as 500kV class power system which constitutes the nucleus of the electric power system. We proposed a new type FCL system (rectifier type FCL), consisting of solid-state diodes, DC reactor and bypass AC reactor, and demonstrated the excellent performances of this FCL by developing the small 6.6kV and 66kV model. It is important to detect the failure of power devices used in the rectifier under the normal operating condition, for keeping the excellent reliability of the power system. In this paper, we have proposed a new failure detecting method of power devices most suitable for the rectifier type FCL. This failure detecting system is simple and compact. We have adapted the proposed system to the 66kV prototype single-phase model and successfully demonstrated to detect the failure of power devices.

Theta frequency background tunes transmission but not summation of spiking responses.

PubMed

Parameshwaran, Dhanya; Bhalla, Upinder S

2013-01-01

Hippocampal neurons are known to fire as a function of frequency and phase of spontaneous network rhythms, associated with the animal's behaviour. This dependence is believed to give rise to precise rate and temporal codes. However, it is not well understood how these periodic membrane potential fluctuations affect the integration of synaptic inputs. Here we used sinusoidal current injection to the soma of CA1 pyramidal neurons in the rat brain slice to simulate background oscillations in the physiologically relevant theta and gamma frequency range. We used a detailed compartmental model to show that somatic current injection gave comparable results to more physiological synaptically driven theta rhythms incorporating excitatory input in the dendrites, and inhibitory input near the soma. We systematically varied the phase of synaptic inputs with respect to this background, and recorded changes in response and summation properties of CA1 neurons using whole-cell patch recordings. The response of the cell was dependent on both the phase of synaptic inputs and frequency of the background input. The probability of the cell spiking for a given synaptic input was up to 40% greater during the depolarized phases between 30-135 degrees of theta frequency current injection. Summation gain on the other hand, was not affected either by the background frequency or the phasic afferent inputs. This flat summation gain, coupled with the enhanced spiking probability during depolarized phases of the theta cycle, resulted in enhanced transmission of summed inputs during the same phase window of 30-135 degrees. Overall, our study suggests that although oscillations provide windows of opportunity to selectively boost transmission and EPSP size, summation of synaptic inputs remains unaffected during membrane oscillations.

Methods for using argon-39 to age-date groundwater using ultra-low-background proportional counting

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

Mace, Emily; Aalseth, Craig; Brandenberger, Jill

Argon-39 can be used as a tracer for age-dating glaciers, oceans, and more recently, groundwater. With a half-life of 269 years, 39Ar fills an intermediate age range gap (50-1,000 years) not currently covered by other common groundwater tracers. Therefore, adding this tracer to the data suite for groundwater studies provides an important tool for improving our understanding of groundwater systems. We present the methods employed for arriving at an age-date for a given sample of argon degassed from groundwater.

An imbalance fault detection method based on data normalization and EMD for marine current turbines.

PubMed

Zhang, Milu; Wang, Tianzhen; Tang, Tianhao; Benbouzid, Mohamed; Diallo, Demba

2017-05-01

This paper proposes an imbalance fault detection method based on data normalization and Empirical Mode Decomposition (EMD) for variable speed direct-drive Marine Current Turbine (MCT) system. The method is based on the MCT stator current under the condition of wave and turbulence. The goal of this method is to extract blade imbalance fault feature, which is concealed by the supply frequency and the environment noise. First, a Generalized Likelihood Ratio Test (GLRT) detector is developed and the monitoring variable is selected by analyzing the relationship between the variables. Then, the selected monitoring variable is converted into a time series through data normalization, which makes the imbalance fault characteristic frequency into a constant. At the end, the monitoring variable is filtered out by EMD method to eliminate the effect of turbulence. The experiments show that the proposed method is robust against turbulence through comparing the different fault severities and the different turbulence intensities. Comparison with other methods, the experimental results indicate the feasibility and efficacy of the proposed method. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Method for exciting inductive-resistive loads with high and controllable direct current

DOEpatents

Hill, Jr., Homer M.

1976-01-01

Apparatus and method for transmitting dc power to a load circuit by applying a dc voltage from a standard waveform synthesizer to duration modulate a bipolar rectangular wave generator. As the amplitude of the dc voltage increases, the widths of the rectangular wave generator output pulses increase, and as the amplitude of the dc voltage decreases, the widths of the rectangular wave generator output pulses decrease. Thus, the waveform synthesizer selectively changes the durations of the rectangular wave generator bipolar output pulses so as to produce a rectangular wave ac carrier that is duration modulated in accordance with and in direct proportion to the voltage amplitude from the synthesizer. Thereupon, by transferring the carrier to the load circuit through an amplifier and a rectifier, the load current also corresponds directly to the voltage amplitude from the synthesizer. To this end, the rectified wave at less than 100% duty factor, amounts to a doubled frequency direct voltage pulse train for applying a direct current to the load, while the current ripple is minimized by a high L/R in the load circuit. In one embodiment, a power transmitting power amplifier means having a dc power supply is matched to the load circuit through a transformer for current magnification without sacrificing load current duration capability, while negative voltage and current feedback are provided in order to insure good output fidelity.

Binary recursive partitioning: background, methods, and application to psychology.

PubMed

Merkle, Edgar C; Shaffer, Victoria A

2011-02-01

Binary recursive partitioning (BRP) is a computationally intensive statistical method that can be used in situations where linear models are often used. Instead of imposing many assumptions to arrive at a tractable statistical model, BRP simply seeks to accurately predict a response variable based on values of predictor variables. The method outputs a decision tree depicting the predictor variables that were related to the response variable, along with the nature of the variables' relationships. No significance tests are involved, and the tree's 'goodness' is judged based on its predictive accuracy. In this paper, we describe BRP methods in a detailed manner and illustrate their use in psychological research. We also provide R code for carrying out the methods.

Detection of admittivity anomaly on high-contrast heterogeneous backgrounds using frequency difference EIT.

PubMed

Jang, J; Seo, J K

2015-06-01

This paper describes a multiple background subtraction method in frequency difference electrical impedance tomography (fdEIT) to detect an admittivity anomaly from a high-contrast background conductivity distribution. The proposed method expands the use of the conventional weighted frequency difference EIT method, which has been used limitedly to detect admittivity anomalies in a roughly homogeneous background. The proposed method can be viewed as multiple weighted difference imaging in fdEIT. Although the spatial resolutions of the output images by fdEIT are very low due to the inherent ill-posedness, numerical simulations and phantom experiments of the proposed method demonstrate its feasibility to detect anomalies. It has potential application in stroke detection in a head model, which is highly heterogeneous due to the skull.

Minimum current principle and variational method in theory of space charge limited flow

NASA Astrophysics Data System (ADS)

Rokhlenko, A.

2015-10-01

In spirit of the principle of least action, which means that when a perturbation is applied to a physical system, its reaction is such that it modifies its state to "agree" with the perturbation by "minimal" change of its initial state. In particular, the electron field emission should produce the minimum current consistent with boundary conditions. It can be found theoretically by solving corresponding equations using different techniques. We apply here the variational method for the current calculation, which can be quite effective even when involving a short set of trial functions. The approach to a better result can be monitored by the total current that should decrease when we on the right track. Here, we present only an illustration for simple geometries of devices with the electron flow. The development of these methods can be useful when the emitter and/or anode shapes make difficult the use of standard approaches. Though direct numerical calculations including particle-in-cell technique are very effective, but theoretical calculations can provide an important insight for understanding general features of flow formation and even sometimes be realized by simpler routines.

Current status of computational methods for transonic unsteady aerodynamics and aeroelastic applications

NASA Technical Reports Server (NTRS)

Edwards, John W.; Malone, John B.

1992-01-01

The current status of computational methods for unsteady aerodynamics and aeroelasticity is reviewed. The key features of challenging aeroelastic applications are discussed in terms of the flowfield state: low-angle high speed flows and high-angle vortex-dominated flows. The critical role played by viscous effects in determining aeroelastic stability for conditions of incipient flow separation is stressed. The need for a variety of flow modeling tools, from linear formulations to implementations of the Navier-Stokes equations, is emphasized. Estimates of computer run times for flutter calculations using several computational methods are given. Applications of these methods for unsteady aerodynamic and transonic flutter calculations for airfoils, wings, and configurations are summarized. Finally, recommendations are made concerning future research directions.

Study of robot landmark recognition with complex background

NASA Astrophysics Data System (ADS)

Huang, Yuqing; Yang, Jia

2007-12-01

It's of great importance for assisting robot in path planning, position navigating and task performing by perceiving and recognising environment characteristic. To solve the problem of monocular-vision-oriented landmark recognition for mobile intelligent robot marching with complex background, a kind of nested region growing algorithm which fused with transcendental color information and based on current maximum convergence center is proposed, allowing invariance localization to changes in position, scale, rotation, jitters and weather conditions. Firstly, a novel experiment threshold based on RGB vision model is used for the first image segmentation, which allowing some objects and partial scenes with similar color to landmarks also are detected with landmarks together. Secondly, with current maximum convergence center on segmented image as each growing seed point, the above region growing algorithm accordingly starts to establish several Regions of Interest (ROI) orderly. According to shape characteristics, a quick and effectual contour analysis based on primitive element is applied in deciding whether current ROI could be reserved or deleted after each region growing, then each ROI is judged initially and positioned. When the position information as feedback is conveyed to the gray image, the whole landmarks are extracted accurately with the second segmentation on the local image that exclusive to landmark area. Finally, landmarks are recognised by Hopfield neural network. Results issued from experiments on a great number of images with both campus and urban district as background show the effectiveness of the proposed algorithm.

Novel method to control antenna currents based on theory of characteristic modes

NASA Astrophysics Data System (ADS)

Elghannai, Ezdeen Ahmed

Characteristic Mode Theory is one of the very few numerical methods that provide a great deal of physical insight because it allows us to determine the natural modes of the radiating structure. The key feature of these modes is that the total induced antenna current, input impedance/admittance and radiation pattern can be expressed as a linear weighted combination of individual modes. Using this decomposition method, it is possible to study the behavior of the individual modes, understand them and therefore control the antennas behavior; in other words, control the currents induced on the antenna structure. This dissertation advances the topic of antenna design by carefully controlling the antenna currents over the desired frequency band to achieve the desired performance specifications for a set of constraints. Here, a systematic method based on the Theory of Characteristic Modes (CM) and lumped reactive loading to achieve the goal of current control is developed. The lumped reactive loads are determined based on the desired behavior of the antenna currents. This technique can also be used to impedance match the antenna to the source/generator connected to it. The technique is much more general than the traditional impedance matching. Generally, the reactive loads that properly control the currents exhibit a combination of Foster and non-Foster behavior. The former can be implemented with lumped passive reactive components, while the latter can be implemented with lumped non-Foster circuits (NFC). The concept of current control is applied to design antennas with a wide band (impedance/pattern) behavior using reactive loads. We successfully applied this novel technique to design multi band and wide band antennas for wireless applications. The technique was developed to match the antenna to resistive and/or complex source impedance and control the radiation pattern at these frequency bands, considering size and volume constraints. A wide band patch antenna was

Current HPLC Methods for Assay of Nano Drug Delivery Systems.

PubMed

Tekkeli, Serife Evrim Kepekci; Kiziltas, Mustafa Volkan

2017-01-01

In nano drug formulations the mechanism of release is a critical process to recognize controlled and targeted drug delivery systems. In order to gain high bioavailability and specificity from the drug to reach its therapeutic goal, the active substance must be loaded into the nanoparticles efficiently. Therefore, the amount in biological fluids or tissues and the remaining amount in nano carriers are very important parameters to understand the potential of the nano drug delivery systems. For this aim, suitable and validated quantitation methods are required to determine released drug concentrations from nano pharmaceutical formulations. HPLC (High Performance Liquid Chromatography) is one of the most common techniques used for determination of released drug content out of nano drug formulations, in different physical conditions, over different periods of time. Since there are many types of HPLC methods depending on detector and column types, it is a challenge for the researchers to choose a suitable method that is simple, fast and validated HPLC techniques for their nano drug delivery systems. This review's goal is to compare HPLC methods that are currently used in different nano drug delivery systems in order to provide detailed and useful information for researchers. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Hierarchical equations of motion method applied to nonequilibrium heat transport in model molecular junctions: Transient heat current and high-order moments of the current operator

NASA Astrophysics Data System (ADS)

Song, Linze; Shi, Qiang

2017-02-01

We present a theoretical approach to study nonequilibrium quantum heat transport in molecular junctions described by a spin-boson type model. Based on the Feynman-Vernon path integral influence functional formalism, expressions for the average value and high-order moments of the heat current operators are derived, which are further obtained directly from the auxiliary density operators (ADOs) in the hierarchical equations of motion (HEOM) method. Distribution of the heat current is then derived from the high-order moments. As the HEOM method is nonperturbative and capable of treating non-Markovian system-environment interactions, the method can be applied to various problems of nonequilibrium quantum heat transport beyond the weak coupling regime.

Compensatable muon collider calorimeter with manageable backgrounds

DOEpatents

Raja, Rajendran

2015-02-17

A method and system for reducing background noise in a particle collider, comprises identifying an interaction point among a plurality of particles within a particle collider associated with a detector element, defining a trigger start time for each of the pixels as the time taken for light to travel from the interaction point to the pixel and a trigger stop time as a selected time after the trigger start time, and collecting only detections that occur between the start trigger time and the stop trigger time in order to thereafter compensate the result from the particle collider to reduce unwanted background detection.

Methods for using argon-39 to age-date groundwater using ultra-low-background proportional counting

DOE PAGES

Mace, Emily; Aalseth, Craig; Brandenberger, Jill; ...

2016-12-21

Argon-39 can be used as a tracer for age-dating glaciers, oceans, and more recently, groundwater. With a half-life of 269 years, 39Ar fills an intermediate age range gap (50–1,000 years) not currently covered by other common groundwater tracers. Therefore, adding this tracer to the data suite for groundwater studies provides an important tool for improving our understanding of groundwater systems. Lastly, we present the methods employed for arriving at an age-date for a given sample of argon degassed from groundwater.

Methods for using argon-39 to age-date groundwater using ultra-low-background proportional counting

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

Mace, Emily; Aalseth, Craig; Brandenberger, Jill

Argon-39 can be used as a tracer for age-dating glaciers, oceans, and more recently, groundwater. With a half-life of 269 years, 39Ar fills an intermediate age range gap (50–1,000 years) not currently covered by other common groundwater tracers. Therefore, adding this tracer to the data suite for groundwater studies provides an important tool for improving our understanding of groundwater systems. Lastly, we present the methods employed for arriving at an age-date for a given sample of argon degassed from groundwater.

Background Oriented Schlieren Implementation in a Jet-Surface Interaction Test

NASA Technical Reports Server (NTRS)

Clem, Michelle M.; Brown, Clifford A.; Fagan, Amy

2013-01-01

Many current and future aircraft designs rely on the wing or other aircraft surfaces to shield the engine noise from observers on the ground. However the available data regarding how a planar surface interacts with a jet to shield and/or enhance the jet noise are currently limited. Therefore, the Jet-Surface Interaction Tests supported by NASA's Fundamental Aeronautics Program's Fixed Wing Project were undertaken to supply experimental data covering a wide range of surface geometries and positions interacting with high-speed jet flows in order to support the development of noise prediction methods. Phase 1 of the Test was conducted in the Aero-Acoustic Propulsion Laboratory at NASA Glenn Research Center and consisted of validating noise prediction schemes for a round nozzle interacting with a planar surface. Phased array data and far-field acoustic data were collected for both the shielded and reflected sides of the surface. Phase 1 results showed that the broadband shock noise was greatly reduced by the surface when the jet was operated at the over-expanded condition, however, it was unclear whether this reduction was due a change in the shock cell structure by the surface. In the present study, Background Oriented Schlieren is implemented in Phase 2 of the Jet-Surface Interaction Tests to investigate whether the planar surface interacts with the high-speed jet ow to change the shock cell structure. Background Oriented Schlieren data are acquired for under-expanded, ideally-expanded, and over-expanded ow regimes for multiple axial and radial positions of the surface at three different plate lengths. These data are analyzed with far-field noise measurements to relate the shock cell structure to the broadband shock noise produced by a jet near a surface.

Microarray image analysis: background estimation using quantile and morphological filters.

PubMed

Bengtsson, Anders; Bengtsson, Henrik

2006-02-28

In a microarray experiment the difference in expression between genes on the same slide is up to 103 fold or more. At low expression, even a small error in the estimate will have great influence on the final test and reference ratios. In addition to the true spot intensity the scanned signal consists of different kinds of noise referred to as background. In order to assess the true spot intensity background must be subtracted. The standard approach to estimate background intensities is to assume they are equal to the intensity levels between spots. In the literature, morphological opening is suggested to be one of the best methods for estimating background this way. This paper examines fundamental properties of rank and quantile filters, which include morphological filters at the extremes, with focus on their ability to estimate between-spot intensity levels. The bias and variance of these filter estimates are driven by the number of background pixels used and their distributions. A new rank-filter algorithm is implemented and compared to methods available in Spot by CSIRO and GenePix Pro by Axon Instruments. Spot's morphological opening has a mean bias between -47 and -248 compared to a bias between 2 and -2 for the rank filter and the variability of the morphological opening estimate is 3 times higher than for the rank filter. The mean bias of Spot's second method, morph.close.open, is between -5 and -16 and the variability is approximately the same as for morphological opening. The variability of GenePix Pro's region-based estimate is more than ten times higher than the variability of the rank-filter estimate and with slightly more bias. The large variability is because the size of the background window changes with spot size. To overcome this, a non-adaptive region-based method is implemented. Its bias and variability are comparable to that of the rank filter. The performance of more advanced rank filters is equal to the best region-based methods. However, in

Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers

DOEpatents

Danby, Gordon T.; Jackson, John W.

1991-01-01

A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations in the particle beam.

Magnetospheric Reconnection in Modified Current-Sheet Equilibria

NASA Astrophysics Data System (ADS)

Newman, D. L.; Goldman, M. V.; Lapenta, G.; Markidis, S.

2012-10-01

Particle simulations of magnetic reconnection in Earth's magnetosphere are frequently initialized with a current-carrying Harris equilibrium superposed on a current-free uniform background plasma. The Harris equilibrium satisfies local charge neutrality, but requires that the sheet current be dominated by the hotter species -- often the ions in Earth's magnetosphere. This constraint is not necessarily consistent with observations. A modified kinetic equilibrium that relaxes this constraint on the currents was proposed by Yamada et al. [Phys. Plasmas., 7, 1781 (2000)] with no background population. These modified equilibria were characterized by an asymptotic converging or diverging electrostatic field normal to the current sheet. By reintroducing the background plasma, we have developed new families of equilibria where the asymptotic fields are suppressed by Debye shielding. Because the electrostatic potential profiles of these new equilibria contain wells and/or barriers capable of spatially isolating different populations of electrons and/or ions, these solutions can be further generalized to include classes of asymmetric kinetic equilibria. Examples of both symmetric and asymmetric equilibria will be presented. The dynamical evolution of these equilibria, when perturbed, will be further explored by means of implicit 2D PIC reconnection simulations, including comparisons with simulations employing standard Harris-equilibrium initializations.

Autogenic-Feedback Training (AFT) as a preventive method for space motion sickness: Background and experimental design

NASA Technical Reports Server (NTRS)

Cowings, Patricia S.; Toscano, William B.

1993-01-01

Finding an effective treatment for the motion sickness-like symptoms that occur in space has become a high priority for NASA. The background research is reviewed and the experimental design of a formal life sciences shuttle flight experiment designed to prevent space motion sickness in shuttle crew members is presented. This experiment utilizes a behavioral medicine approach to solving this problem. This method, Autogenic-Feedback Training (AFT), involves training subjects to voluntarily control several of their own physiological responses to environmental stressors. AFT has been used reliably to increase tolerance to motion sickness during ground-based tests in over 200 men and women under a variety of conditions that induce motion sickness, and preliminary evidence from space suggests that AFT may be an effective treatment for space motion sickness as well. Proposed changes to this experiment for future manifests are included.

Pulse shape discrimination for background rejection in germanium gamma-ray detectors

NASA Technical Reports Server (NTRS)

Feffer, P. T.; Smith, D. M.; Campbell, R. D.; Primbsch, J. H.; Lin, R. P.

1989-01-01

A pulse-shape discrimination (PSD) technique is developed to reject the beta-decay background resulting from activation of Ge gamma-ray detectors by cosmic-ray secondaries. These beta decays are a major source of background at 0.2-2 MeV energies in well shielded Ge detector systems. The technique exploits the difference between the detected current pulse shapes of single- and multiple-site energy depositions within the detector: beta decays are primarily single-site events, while photons at these energies typically Compton scatter before being photoelectrically absorbed to produce multiple-site events. Depending upon the amount of background due to sources other than beta decay, PSD can more than double the detector sensitivity.

Listening to Students from Refugee Backgrounds: Lessons for Education Professionals

ERIC Educational Resources Information Center

Mthethwa-Sommers, Shirley; Kisiara, Otieno

2015-01-01

This article is based on a study that examined how students from refugee backgrounds cope with victimization and bullying in three urban high schools in the United States. Qualitative methods of data collection and analysis were employed. Twelve high school students from refugee backgrounds participated in the study, which involved focus group…

Direct bonded HOPG - Analyzer support without background source

NASA Astrophysics Data System (ADS)

Groitl, Felix; Kitaura, Hidetoshi; Nishiki, Naomi; Rønnow, Henrik M.

2018-04-01

A new production process allows a direct bonding of HOPG crystals on Si wafers. This new method facilitates the production of analyzer crystals with support structure without the use of additional, background inducing fixation material, e.g. glue, wax and screws. This new method is especially interesting for the upcoming generation of CAMEA-type multiplexing spectrometers. These instruments allow for a drastic performance increase due to the increased angular coverage and multiple energy analysis. Exploiting the transparency of multiple HOPG for cold neutrons, a consecutive arrangement of HOPG analyzer crystals per Q-channel can be achieved. This implies that neutrons travel through up to 10 arrays of analyzer crystals before reaching the analyzer corresponding to their energy. Hence, a careful choice of the fixation method for the analyzer crystals in regards to transparency and background is necessary. Here, we present first results on the diffraction and mechanical performance of direct bonded analyzer crystals.

Field-induced phase transitions in chiral smectic liquid crystals studied by the constant current method

NASA Astrophysics Data System (ADS)

H, Dhaouadi; R, Zgueb; O, Riahi; F, Trabelsi; T, Othman

2016-05-01

In ferroelectric liquid crystals, phase transitions can be induced by an electric field. The current constant method allows these transition to be quickly localized and thus the (E,T) phase diagram of the studied product can be obtained. In this work, we make a slight modification to the measurement principles based on this method. This modification allows the characteristic parameters of ferroelectric liquid crystal to be quantitatively measured. The use of a current square signal highlights a phenomenon of ferroelectric hysteresis with remnant polarization at null field, which points out an effect of memory in this compound.

Novel methods to optimize the effects of transcranial direct current stimulation: a systematic review of transcranial direct current stimulation patents.

PubMed

Malavera, Alejandra; Vasquez, Alejandra; Fregni, Felipe

2015-01-01

Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that has been extensively studied. While there have been initial positive results in some clinical trials, there is still variability in tDCS results. The aim of this article is to review and discuss patents assessing novel methods to optimize the use of tDCS. A systematic review was performed using Google patents database with tDCS as the main technique, with patents filling date between 2010 and 2015. Twenty-two patents met our inclusion criteria. These patents attempt to address current tDCS limitations. Only a few of them have been investigated in clinical trials (i.e., high-definition tDCS), and indeed most of them have not been tested before in human trials. Further clinical testing is required to assess which patents are more likely to optimize the effects of tDCS. We discuss the potential optimization of tDCS based on these patents and the current experience with standard tDCS.

Methods, systems and apparatus for optimization of third harmonic current injection in a multi-phase machine

DOEpatents

Gallegos-Lopez, Gabriel

2012-10-02

Methods, system and apparatus are provided for increasing voltage utilization in a five-phase vector controlled machine drive system that employs third harmonic current injection to increase torque and power output by a five-phase machine. To do so, a fundamental current angle of a fundamental current vector is optimized for each particular torque-speed of operating point of the five-phase machine.

Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers

DOEpatents

Danby, G.T.; Jackson, J.W.

1990-03-19

A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations (dB/dt) in the particle beam.

Reduction of background clutter in structured lighting systems

DOEpatents

Carlson, Jeffrey J.; Giles, Michael K.; Padilla, Denise D.; Davidson, Jr., Patrick A.; Novick, David K.; Wilson, Christopher W.

2010-06-22

Methods for segmenting the reflected light of an illumination source having a characteristic wavelength from background illumination (i.e. clutter) in structured lighting systems can comprise pulsing the light source used to illuminate a scene, pulsing the light source synchronously with the opening of a shutter in an imaging device, estimating the contribution of background clutter by interpolation of images of the scene collected at multiple spectral bands not including the characteristic wavelength and subtracting the estimated background contribution from an image of the scene comprising the wavelength of the light source and, placing a polarizing filter between the imaging device and the scene, where the illumination source can be polarized in the same orientation as the polarizing filter. Apparatus for segmenting the light of an illumination source from background illumination can comprise an illuminator, an image receiver for receiving images of multiple spectral bands, a processor for calculations and interpolations, and a polarizing filter.

Assessment of background particulate matter concentrations in small cities and rural locations--Prince George, Canada.

PubMed

Veira, Andreas; Jackson, Peter L; Ainslie, Bruce; Fudge, Dennis

2013-07-01

This study investigates the development and application of a simple method to calculate annual and seasonal PM2.5 and PM10 background concentrations in small cities and rural areas. The Low Pollution Sectors and Conditions (LPSC) method is based on existing measured long-term data sets and is designed for locations where particulate matter (PM) monitors are only influenced by local anthropogenic emission sources from particular wind sectors. The LPSC method combines the analysis of measured hourly meteorological data, PM concentrations, and geographical emission source distributions. PM background levels emerge from measured data for specific wind conditions, where air parcel trajectories measured at a monitoring station are assumed to have passed over geographic sectors with negligible local emissions. Seasonal and annual background levels were estimated for two monitoring stations in Prince George, Canada, and the method was also applied to four other small cities (Burns Lake, Houston, Quesnel, Smithers) in northern British Columbia. The analysis showed reasonable background concentrations for both monitoring stations in Prince George, whereas annual PM10 background concentrations at two of the other locations and PM2.5 background concentrations at one other location were implausibly high. For those locations where the LPSC method was successful, annual background levels ranged between 1.8 +/- 0.1 microg/m3 and 2.5 +/- 0.1 microg/m3 for PM2.5 and between 6.3 +/- 0.3 microg/m3 and 8.5 +/- 0.3 microg/m3 for PM10. Precipitation effects and patterns of seasonal variability in the estimated background concentrations were detectable for all locations where the method was successful. Overall the method was dependent on the configuration of local geography and sources with respect to the monitoring location, and may fail at some locations and under some conditions. Where applicable, the LPSC method can provide a fast and cost-efficient way to estimate background PM

Review of Monte Carlo simulations for backgrounds from radioactivity

NASA Astrophysics Data System (ADS)

Selvi, Marco

2013-08-01

For all experiments dealing with the rare event searches (neutrino, dark matter, neutrino-less double-beta decay), the reduction of the radioactive background is one of the most important and difficult tasks. There are basically two types of background, electron recoils and nuclear recoils. The electron recoil background is mostly from the gamma rays through the radioactive decay. The nuclear recoil background is from neutrons from spontaneous fission, (α, n) reactions and muoninduced interactions (spallations, photo-nuclear and hadronic interaction). The external gammas and neutrons from the muons and laboratory environment, can be reduced by operating the detector at deep underground laboratories and by placing active or passive shield materials around the detector. The radioactivity of the detector materials also contributes to the background; in order to reduce it a careful screening campaign is mandatory to select highly radio-pure materials. In this review I present the status of current Monte Carlo simulations aimed to estimate and reproduce the background induced by gamma and neutron radioactivity of the materials and the shield of rare event search experiment. For the electromagnetic background a good level of agreement between the data and the MC simulation has been reached by the XENON100 and EDELWEISS experiments, using the GEANT4 toolkit. For the neutron background, a comparison between the yield of neutrons from spontaneous fission and (α, n) obtained with two dedicated softwares, SOURCES-4A and the one developed by Mei-Zhang-Hime, show a good overall agreement, with total yields within a factor 2 difference. The energy spectra from SOURCES-4A are in general smoother, while those from MZH presents sharp peaks. The neutron propagation through various materials has been studied with two MC codes, GEANT4 and MCNPX, showing a reasonably good agreement, inside 50% discrepancy.

Direct current power delivery system and method

DOEpatents

Zhang, Di; Garces, Luis Jose; Dai, Jian; Lai, Rixin

2016-09-06

A power transmission system includes a first unit for carrying out the steps of receiving high voltage direct current (HVDC) power from an HVDC power line, generating an alternating current (AC) component indicative of a status of the first unit, and adding the AC component to the HVDC power line. Further, the power transmission system includes a second unit for carrying out the steps of generating a direct current (DC) voltage to transfer the HVDC power on the HVDC power line, wherein the HVDC power line is coupled between the first unit and the second unit, detecting a presence or an absence of the added AC component in the HVDC power line, and determining the status of the first unit based on the added AC component.

Method and apparatus for detecting cyber attacks on an alternating current power grid

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

McEachern, Alexander; Hofmann, Ronald

A method and apparatus for detecting cyber attacks on remotely-operable elements of an alternating current distribution grid. Two state estimates of the distribution grid are prepared, one of which uses micro-synchrophasors. A difference between the two state estimates indicates a possible cyber attack.

The Qatar Biobank: background and methods.

PubMed

Al Kuwari, Hanan; Al Thani, Asma; Al Marri, Ajayeb; Al Kaabi, Abdulla; Abderrahim, Hadi; Afifi, Nahla; Qafoud, Fatima; Chan, Queenie; Tzoulaki, Ioanna; Downey, Paul; Ward, Heather; Murphy, Neil; Riboli, Elio; Elliott, Paul

2015-12-03

pilot has proven that recruitment of volunteers into the Qatar Biobank project with intensive baseline measurements of behavioural, physical, and clinical characteristics is well accepted and logistically feasible. Qatar Biobank will provide a powerful resource to investigate the major determinants of ill-health and well-being in Qatar, providing valuable insights into the current and future public health burden that faces the country.

Diagnostic methods for platelet bacteria screening: current status and developments.

PubMed

Störmer, Melanie; Vollmer, Tanja

2014-02-01

Bacterial contamination of blood components and the prevention of transfusion-associated bacterial infection still remains a major challenge in transfusion medicine. Over the past few decades, a significant reduction in the transmission of viral infections has been achieved due to the introduction of mandatory virus screening. Platelet concentrates (PCs) represent one of the highest risks for bacterial infection. This is due to the required storage conditions for PCs in gas-permeable containers at room temperature with constant agitation, which support bacterial proliferation from low contamination levels to high titers. In contrast to virus screening, since 1997 in Germany bacterial testing of PCs is only performed as a routine quality control or, since 2008, to prolong the shelf life to 5 days. In general, bacterial screening of PCs by cultivation methods is implemented by the various blood services. Although these culturing systems will remain the gold standard, the significance of rapid methods for screening for bacterial contamination has increased over the last few years. These new methods provide powerful tools for increasing the bacterial safety of blood components. This article summarizes the course of policies and provisions introduced to increase bacterial safety of blood components in Germany. Furthermore, we give an overview of the different diagnostic methods for bacterial screening of PCs and their current applicability in routine screening processes.

Diagnostic Methods for Platelet Bacteria Screening: Current Status and Developments

PubMed Central

Störmer, Melanie; Vollmer, Tanja

2014-01-01

Summary Bacterial contamination of blood components and the prevention of transfusion-associated bacterial infection still remains a major challenge in transfusion medicine. Over the past few decades, a significant reduction in the transmission of viral infections has been achieved due to the introduction of mandatory virus screening. Platelet concentrates (PCs) represent one of the highest risks for bacterial infection. This is due to the required storage conditions for PCs in gas-permeable containers at room temperature with constant agitation, which support bacterial proliferation from low contamination levels to high titers. In contrast to virus screening, since 1997 in Germany bacterial testing of PCs is only performed as a routine quality control or, since 2008, to prolong the shelf life to 5 days. In general, bacterial screening of PCs by cultivation methods is implemented by the various blood services. Although these culturing systems will remain the gold standard, the significance of rapid methods for screening for bacterial contamination has increased over the last few years. These new methods provide powerful tools for increasing the bacterial safety of blood components. This article summarizes the course of policies and provisions introduced to increase bacterial safety of blood components in Germany. Furthermore, we give an overview of the different diagnostic methods for bacterial screening of PCs and their current applicability in routine screening processes. PMID:24659944

Separation of foreground and background from light field using gradient information.

PubMed

Lee, Jae Young; Park, Rae-Hong

2017-02-01

Studies of computer vision or machine vision applications using a light field camera have been increasing in recent years. However, the abilities that the light field camera has are not fully used in these applications. In this paper, we propose a method for direct separation of foreground and background that uses the gradient information and can be used in various applications such as pre-processing. From an optical phenomenon whereby the bundles of rays from the background are flipped, we derive that the disparity sign of the background in the captured three-dimensional scene has the opposite disparity sign of the foreground. Using the majority-weighted voting algorithm based on the gradient information with the Lambertian assumption and the gradient constraint, the foreground and background can be separated at each pixel. In regard to pre-processing, the proposed method can be used for various applications such as occlusion and saliency detection, disparity estimation, and so on. Experimental results with the EPFL light field dataset and Stanford Lytro light field dataset show that the proposed method achieves better performance in terms of the occlusion detection, and thus can be effectively used in pre-processing for saliency detection and disparity estimation.

Method for determining transport critical current densities and flux penetration depth in bulk superconductors

NASA Technical Reports Server (NTRS)

Israelsson, Ulf E. (Inventor); Strayer, Donald M. (Inventor)

1992-01-01

A contact-less method for determining transport critical current density and flux penetration depth in bulk superconductor material. A compressor having a hollow interior and a plunger for selectively reducing the free space area for distribution of the magnetic flux therein are formed of superconductor material. Analytical relationships, based upon the critical state model, Maxwell's equations and geometrical relationships define transport critical current density and flux penetration depth in terms of the initial trapped magnetic flux density and the ratio between initial and final magnetic flux densities whereby data may be reliably determined by means of the simple test apparatus for evaluating the current density and flux penetration depth.

Cosmic microwave background bispectrum from recombination.

PubMed

Huang, Zhiqi; Vernizzi, Filippo

2013-03-08

We compute the cosmic microwave background temperature bispectrum generated by nonlinearities at recombination on all scales. We use CosmoLib2nd, a numerical Boltzmann code at second order to compute cosmic microwave background bispectra on the full sky. We consistently include all effects except gravitational lensing, which can be added to our result using standard methods. The bispectrum is peaked on squeezed triangles and agrees with the analytic approximation in the squeezed limit at the few percent level for all the scales where this is applicable. On smaller scales, we recover previous results on perturbed recombination. For cosmic-variance limited data to l(max)=2000, its signal-to-noise ratio is S/N=0.47, corresponding to f(NL)(eff)=-2.79, and will bias a local signal by f(NL)(loc) ~/= 0.82.

A new evaluation method of electron optical performance of high beam current probe forming systems.

PubMed

Fujita, Shin; Shimoyama, Hiroshi

2005-10-01

A new numerical simulation method is presented for the electron optical property analysis of probe forming systems with point cathode guns such as cold field emitters and the Schottky emitters. It has long been recognized that the gun aberrations are important parameters to be considered since the intrinsically high brightness of the point cathode gun is reduced due to its spherical aberration. The simulation method can evaluate the 'threshold beam current I(th)' above which the apparent brightness starts to decrease from the intrinsic value. It is found that the threshold depends on the 'electron gun focal length' as well as on the spherical aberration of the gun. Formulas are presented to estimate the brightness reduction as a function of the beam current. The gun brightness reduction must be included when the probe property (the relation between the beam current l(b) and the probe size on the sample, d) of the entire electron optical column is evaluated. Formulas that explicitly consider the gun aberrations into account are presented. It is shown that the probe property curve consists of three segments in the order of increasing beam current: (i) the constant probe size region, (ii) the brightness limited region where the probe size increases as d approximately I(b)(3/8), and (iii) the angular current intensity limited region in which the beam size increases rapidly as d approximately I(b)(3/2). Some strategies are suggested to increase the threshold beam current and to extend the effective beam current range of the point cathode gun into micro ampere regime.

Measuring Extinction in Local Group Galaxies Using Background Galaxies

NASA Astrophysics Data System (ADS)

Wyder, T. K.; Hodge, P. W.

1999-05-01

Knowledge of the distribution and quantity of dust in galaxies is important for understanding their structure and evolution. The goal of our research is to measure the total extinction through Local Group galaxies using measured properties of background galaxies. Our method relies on the SExtractor software as an objective and automated method of detecting background galaxies. In an initial test, we have explored two WFPC2 fields in the SMC and two in M31 obtained from the HST archives. The two pointings in the SMC are fields around the open clusters L31 and B83 while the two M31 fields target the globular clusters G1 and G170. Except for the G1 observations of M31, the fields chosen are very crowded (even when observed with HST) and we chose them as a particularly stringent test of the method. We performed several experiments using a series of completeness tests that involved superimposing comparison fields, adjusted to the equivalent exposure time, from the HST Medium-Deep and Groth-Westphal surveys. These tests showed that for crowded fields, such as the two in the core of the SMC and the one in the bulge of M31, this automated method of detecting galaxies can be completely dominated by the effects of crowding. For these fields, only a small fraction of the added galaxies was recovered. However, in the outlying G1 field in M31, almost all of the added galaxies were recovered. The numbers of actual background galaxies in this field are consistent with zero extinction. As a follow-up experiment, we used image processing techniques to suppress stellar objects while enhancing objects with non-stellar, more gradual luminosity profiles. This method yielded significant numbers of background galaxies in even the most crowded fields, which we are now analyzing to determine the total extinction and reddening caused by the foreground galaxy.

RenderView: physics-based multi- and hyperspectral rendering using measured background panoramics

NASA Astrophysics Data System (ADS)

Talcott, Denise M.; Brown, Wade W.; Thomas, David J.

2003-09-01

As part of the survivability engineering process it is necessary to accurately model and visualize the vehicle signatures in multi- or hyperspectral bands of interest. The signature at a given wavelength is a function of the surface optical properties, reflection of the background and, in the thermal region, the emission of thermal radiation. Currently, it is difficult to obtain and utilize background models that are of sufficient fidelity when compared with the vehicle models. In addition, the background models create an additional layer of uncertainty in estimating the vehicles signature. Therefore, to meet exacting rendering requirements we have developed RenderView, which incorporates the full bidirectional reflectance distribution function (BRDF). Instead of using a modeled background we have incorporated a measured calibrated background panoramic image to provide the high fidelity background interaction. Uncertainty in the background signature is reduced to the error in the measurement which is considerably smaller than the uncertainty inherent in a modeled background. RenderView utilizes a number of different descriptions of the BRDF, including the Sandford-Robertson. In addition, it provides complete conservation of energy with off axis sampling. A description of RenderView will be presented along with a methodology developed for collecting background panoramics. Examples of the RenderView output and the background panoramics will be presented along with our approach to handling the solar irradiance problem.

Second Language Comprehensibility Revisited: Investigating the Effects of Learner Background

ERIC Educational Resources Information Center

Crowther, Dustin; Trofimovich, Pavel; Saito, Kazuya; Isaacs, Talia

2015-01-01

The current study investigated first language (L1) effects on listener judgment of comprehensibility and accentedness in second language (L2) speech. The participants were 45 university-level adult speakers of English from three L1 backgrounds (Chinese, Hindi, Farsi), performing a picture narrative task. Ten native English listeners used…

Develop Accurate Methods for Characterizing and Quantifying Cohesive Sediment Erosion Under Combined Current-Wave Conditions

DTIC Science & Technology

2017-09-01

ER D C/ CH L TR -1 7- 15 Strategic Environmental Research and Development Program Develop Accurate Methods for Characterizing and...current environments. This research will provide more accurate methods for assessing contaminated sediment stability for many DoD and Environmental...47.88026 pascals yards 0.9144 meters ERDC/CHL TR-17-15 xi Executive Summary Objective The proposed research goal is to develop laboratory methods

Experimental methods in aquatic respirometry: the importance of mixing devices and accounting for background respiration.

PubMed

Rodgers, G G; Tenzing, P; Clark, T D

2016-01-01

In light of an increasing trend in fish biology towards using static respirometry techniques without the inclusion of a mixing mechanism and without accurately accounting for the influence of microbial (background) respiration, this paper quantifies the effect of these approaches on the oxygen consumption rates (ṀO2 ) measured from juvenile barramundi Lates calcarifer (mean ± s.e. mass = 20·31 ± 0·81 g) and adult spiny chromis damselfish Acanthochromis polyacanthus (22·03 ± 2·53 g). Background respiration changed consistently and in a sigmoidal manner over time in the treatment with a mixing device (inline recirculation pump), whereas attempts to measure background respiration in the non-mixed treatment yielded highly variable estimates of ṀO2 that were probably artefacts due to the lack of water movement over the oxygen sensor during measurement periods. This had clear consequences when accounting for background respiration in the calculations of fish ṀO2 . Exclusion of a mixing device caused a significantly lower estimate of ṀO2 in both species and reduced the capacity to detect differences between individuals as well as differences within an individual over time. There was evidence to suggest that the magnitude of these effects was dependent on the spontaneous activity levels of the fish, as the difference between mixed and non-mixed treatments was more pronounced for L. calcarifer (sedentary) than for A. polyacanthus (more spontaneously active). It is clear that respirometry set-ups for sedentary species must contain a mixing device to prevent oxygen stratification inside the respirometer. While more active species may provide a higher level of water mixing during respirometry measurements and theoretically reduce the need for a mixing device, the level of mixing cannot be quantified and may change with diurnal cycles in activity. To ensure consistency across studies without relying on fish activity levels, and to enable accurate assessments of

Study of Current Measurement Method Based on Circular Magnetic Field Sensing Array

PubMed Central

Li, Zhenhua; Zhang, Siqiu; Wu, Zhengtian; Tao, Yuan

2018-01-01

Classic core-based instrument transformers are more prone to magnetic saturation. This affects the measurement accuracy of such transformers and limits their applications in measuring large direct current (DC). Moreover, protection and control systems may exhibit malfunctions due to such measurement errors. This paper presents a more accurate method for current measurement based on a circular magnetic field sensing array. The proposed measurement approach utilizes multiple hall sensors that are evenly distributed on a circle. The average value of all hall sensors is regarded as the final measurement. The calculation model is established in the case of magnetic field interference of the parallel wire, and the simulation results show that the error decreases significantly when the number of hall sensors n is greater than 8. The measurement error is less than 0.06% when the wire spacing is greater than 2.5 times the radius of the sensor array. A simulation study on the off-center primary conductor is conducted, and a kind of hall sensor compensation method is adopted to improve the accuracy. The simulation and test results indicate that the measurement error of the system is less than 0.1%. PMID:29734742

Study of Current Measurement Method Based on Circular Magnetic Field Sensing Array.

PubMed

Li, Zhenhua; Zhang, Siqiu; Wu, Zhengtian; Abu-Siada, Ahmed; Tao, Yuan

2018-05-05

Classic core-based instrument transformers are more prone to magnetic saturation. This affects the measurement accuracy of such transformers and limits their applications in measuring large direct current (DC). Moreover, protection and control systems may exhibit malfunctions due to such measurement errors. This paper presents a more accurate method for current measurement based on a circular magnetic field sensing array. The proposed measurement approach utilizes multiple hall sensors that are evenly distributed on a circle. The average value of all hall sensors is regarded as the final measurement. The calculation model is established in the case of magnetic field interference of the parallel wire, and the simulation results show that the error decreases significantly when the number of hall sensors n is greater than 8. The measurement error is less than 0.06% when the wire spacing is greater than 2.5 times the radius of the sensor array. A simulation study on the off-center primary conductor is conducted, and a kind of hall sensor compensation method is adopted to improve the accuracy. The simulation and test results indicate that the measurement error of the system is less than 0.1%.

Ground-to-air flow visualization using Solar Calcium-K line Background-Oriented Schlieren

NASA Astrophysics Data System (ADS)

Hill, Michael A.; Haering, Edward A.

2017-01-01

The Calcium-K Eclipse Background-Oriented Schlieren experiment was performed as a proof of concept test to evaluate the effectiveness of using the solar disk as a background to perform the Background-Oriented Schlieren (BOS) method of flow visualization. A ground-based imaging system was equipped with a Calcium-K line optical etalon filter to enable the use of the chromosphere of the sun as the irregular background to be used for BOS. A US Air Force T-38 aircraft performed three supersonic runs which eclipsed the sun as viewed from the imaging system. The images were successfully post-processed using optical flow methods to qualitatively reveal the density gradients in the flow around the aircraft.

Nodal Analysis Optimization Based on the Use of Virtual Current Sources: A Powerful New Pedagogical Method

ERIC Educational Resources Information Center

Chatzarakis, G. E.

2009-01-01

This paper presents a new pedagogical method for nodal analysis optimization based on the use of virtual current sources, applicable to any linear electric circuit (LEC), regardless of its complexity. The proposed method leads to straightforward solutions, mostly arrived at by inspection. Furthermore, the method is easily adapted to computer…

Evaluation and comparison of 50 Hz current threshold of electrocutaneous sensations using different methods

PubMed Central

Lindenblatt, G.; Silny, J.

2006-01-01

Leakage currents, tiny currents flowing from an everyday-life appliance through the body to the ground, can cause a non-adequate perception (called electrocutaneous sensation, ECS) or even pain and should be avoided. Safety standards for low-frequency range are based on experimental results of current thresholds of electrocutaneous sensations, which however show a wide range between about 50 μA (rms) and 1000 μA (rms). In order to be able to explain these differences, the perception threshold was measured repeatedly in experiments with test persons under identical experimental setup, but by means of different methods (measuring strategies), namely: direct adjustment, classical threshold as amperage of 50% perception probability, and confidence rating procedure of signal detection theory. The current is injected using a 1 cm2 electrode at the highly touch sensitive part of the index fingertip. These investigations show for the first time that the threshold of electrocutaneous sensations is influenced both by adaptation to the non-adequate stimulus and individual, emotional factors. Therefore, classical methods, on which the majority of the safety investigations are based, cannot be used to determine a leakage current threshold. The confidence rating procedure of the modern signal detection theory yields a value of 179.5 μA (rms) at 50 Hz power supply net frequency as the lower end of the 95% confidence range considering the variance in the investigated group. This value is expected to be free of adaptation influences, and is distinctly lower than the European limits and supports the stricter regulations of Canada and USA. PMID:17111461

An improved current potential method for fast computation of stellarator coil shapes

NASA Astrophysics Data System (ADS)

Landreman, Matt

2017-04-01

Several fast methods for computing stellarator coil shapes are compared, including the classical NESCOIL procedure (Merkel 1987 Nucl. Fusion 27 867), its generalization using truncated singular value decomposition, and a Tikhonov regularization approach we call REGCOIL in which the squared current density is included in the objective function. Considering W7-X and NCSX geometries, and for any desired level of regularization, we find the REGCOIL approach simultaneously achieves lower surface-averaged and maximum values of both current density (on the coil winding surface) and normal magnetic field (on the desired plasma surface). This approach therefore can simultaneously improve the free-boundary reconstruction of the target plasma shape while substantially increasing the minimum distances between coils, preventing collisions between coils while improving access for ports and maintenance. The REGCOIL method also allows finer control over the level of regularization, it preserves convexity to ensure the local optimum found is the global optimum, and it eliminates two pathologies of NESCOIL: the resulting coil shapes become independent of the arbitrary choice of angles used to parameterize the coil surface, and the resulting coil shapes converge rather than diverge as Fourier resolution is increased. We therefore contend that REGCOIL should be used instead of NESCOIL for applications in which a fast and robust method for coil calculation is needed, such as when targeting coil complexity in fixed-boundary plasma optimization, or for scoping new stellarator geometries.

Improvements in Technique of NMR Imaging and NMR Diffusion Measurements in the Presence of Background Gradients.

NASA Astrophysics Data System (ADS)

Lian, Jianyu

In this work, modification of the cosine current distribution rf coil, PCOS, has been introduced and tested. The coil produces a very homogeneous rf magnetic field, and it is inexpensive to build and easy to tune for multiple resonance frequency. The geometrical parameters of the coil are optimized to produce the most homogeneous rf field over a large volume. To avoid rf field distortion when the coil length is comparable to a quarter wavelength, a parallel PCOS coil is proposed and discussed. For testing rf coils and correcting B _1 in NMR experiments, a simple, rugged and accurate NMR rf field mapping technique has been developed. The method has been tested and used in 1D, 2D, 3D and in vivo rf mapping experiments. The method has been proven to be very useful in the design of rf coils. To preserve the linear relation between rf output applied on an rf coil and modulating input for an rf modulating -amplifying system of NMR imaging spectrometer, a quadrature feedback loop is employed in an rf modulator with two orthogonal rf channels to correct the amplitude and phase non-linearities caused by the rf components in the rf system. The modulator is very linear over a large range and it can generate an arbitrary rf shape. A diffusion imaging sequence has been developed for measuring and imaging diffusion in the presence of background gradients. Cross terms between the diffusion sensitizing gradients and background gradients or imaging gradients can complicate diffusion measurement and make the interpretation of NMR diffusion data ambiguous, but these have been eliminated in this method. Further, the background gradients has been measured and imaged. A dipole random distribution model has been established to study background magnetic fields Delta B and background magnetic gradients G_0 produced by small particles in a sample when it is in a B_0 field. From this model, the minimum distance that a spin can approach a particle can be determined by measuring

Bivariate quadratic method in quantifying the differential capacitance and energy capacity of supercapacitors under high current operation

NASA Astrophysics Data System (ADS)

Goh, Chin-Teng; Cruden, Andrew

2014-11-01

Capacitance and resistance are the fundamental electrical parameters used to evaluate the electrical characteristics of a supercapacitor, namely the dynamic voltage response, energy capacity, state of charge and health condition. In the British Standards EN62391 and EN62576, the constant capacitance method can be further improved with a differential capacitance that more accurately describes the dynamic voltage response of supercapacitors. This paper presents a novel bivariate quadratic based method to model the dynamic voltage response of supercapacitors under high current charge-discharge cycling, and to enable the derivation of the differential capacitance and energy capacity directly from terminal measurements, i.e. voltage and current, rather than from multiple pulsed-current or excitation signal tests across different bias levels. The estimation results the author achieves are in close agreement with experimental measurements, within a relative error of 0.2%, at various high current levels (25-200 A), more accurate than the constant capacitance method (4-7%). The archival value of this paper is the introduction of an improved quantification method for the electrical characteristics of supercapacitors, and the disclosure of the distinct properties of supercapacitors: the nonlinear capacitance-voltage characteristic, capacitance variation between charging and discharging, and distribution of energy capacity across the operating voltage window.

Measurements of SWIR backgrounds using the swux unit of measure

NASA Astrophysics Data System (ADS)

Richards, A.; Hübner, M.; Vollmer, M.

2018-04-01

The SWIR waveband between 0.8μm-1.8μm is getting increasingly exploited by imaging systems in a variety of different applications, including persistent imaging for security and surveillance of high-value assets, handheld tactical imagers, range-gated imaging systems and imaging LADAR for driverless vehicles. The vast majority of these applications utilize lattice-matched InGaAs detectors in their imaging sensors, and these sensors are rapidly falling in price, leading to their widening adoption. As these sensors are used in novel applications and locations, it is important that ambient SWIR backgrounds be understood and characterized for a variety of different field conditions, primarily for the purposes of system performance modeling of SNR and range metrics. SWIR irradiance backgrounds do not consistently track visible-light illumination at all. There is currently little of this type of information in the open literature, particularly measurements of SWIR backgrounds in urban areas, natural areas, or indoors. This paper presents field measurements done with an InGaAs detector calibrated in the swux unit of InGaAs-band-specific irradiance proposed by two of the authors in 2017. Simultaneous measurements of illuminance levels (in lux) at these sites are presented, as well as visible and InGaAs camera images of the scenery at some of these measurement sites. The swux and lux measurement hardware is described, along with the methods used to calibrate it. Finally, the swux levels during the partial and total phases of the total solar eclipse of 2017 are presented, along with curves fitted to the data from a theoretical model, based on obscuration of the sun by the moon. The apparent differences between photometric and swux measurements will be discussed.

The EOS land validation core sites: background information and current status

USGS Publications Warehouse

Morisette, J.; Privette, J.L.; Justice, C.; Olson, D.; Dwyer, John L.; Davis, P.; Starr, D.; Wickland, D.

1999-01-01

The EOS Land Validation Core Sites1 will provide the user community with timely ground, aircraft, and satellite data for EOS science and validation investigations. The sites, currently 24 distributed worldwide, represent a consensus among the instrument teams and validation investigators and represent a range of global biome types (see Figure 1 and Table 1; Privette et al., 1999; Justice et al., 1998). The sites typically have a history of in situ and remote observations and can expect continued monitoring and land cover research activities. In many cases, a Core Site will have a tower equipped with above-canopy instrumentation for nearcontinuous sampling of landscape radiometric, energy and CO2 flux, meteorological variables, and atmospheric aerosol and water vapor data. These will be complemented by intensive field measurement campaigns. The data collected at these sites will provide an important resource for the broader science community. These sites can also provide a foundation for a validation network supported and used by all international space agencies.

An improved algorithm of laser spot center detection in strong noise background

NASA Astrophysics Data System (ADS)

Zhang, Le; Wang, Qianqian; Cui, Xutai; Zhao, Yu; Peng, Zhong

2018-01-01

Laser spot center detection is demanded in many applications. The common algorithms for laser spot center detection such as centroid and Hough transform method have poor anti-interference ability and low detection accuracy in the condition of strong background noise. In this paper, firstly, the median filtering was used to remove the noise while preserving the edge details of the image. Secondly, the binarization of the laser facula image was carried out to extract target image from background. Then the morphological filtering was performed to eliminate the noise points inside and outside the spot. At last, the edge of pretreated facula image was extracted and the laser spot center was obtained by using the circle fitting method. In the foundation of the circle fitting algorithm, the improved algorithm added median filtering, morphological filtering and other processing methods. This method could effectively filter background noise through theoretical analysis and experimental verification, which enhanced the anti-interference ability of laser spot center detection and also improved the detection accuracy.

Impingement-Current-Erosion Characteristics of Accelerator Grids on Two-Grid Ion Thrusters

NASA Technical Reports Server (NTRS)

Barker, Timothy

1996-01-01

Accelerator grid sputter erosion resulting from charge-exchange-ion impingement is considered to be a primary cause of failure for electrostatic ion thrusters. An experimental method was developed and implemented to measure erosion characteristics of ion-thruster accel-grids for two-grid systems as a function of beam current, accel-grid potential, and facility background pressure. Intricate accelerator grid erosion patterns, that are typically produced in a short time (a few hours), are shown. Accelerator grid volumetric and depth-erosion rates are calculated from these erosion patterns and reported for each of the parameters investigated. A simple theoretical volumetric erosion model yields results that are compared to experimental findings. Results from the model and experiments agree to within 10%, thereby verifying the testing technique. In general, the local distribution of erosion is concentrated in pits between three adjacent holes and trenches that join pits. The shapes of the pits and trenches are shown to be dependent upon operating conditions. Increases in beam current and the accel-grid voltage magnitude lead to deeper pits and trenches. Competing effects cause complex changes in depth-erosion rates as background pressure is increased. Shape factors that describe pits and trenches (i.e. ratio of the average erosion width to the maximum possible width) are also affected in relatively complex ways by changes in beam current, ac tel-grid voltage magnitude, and background pressure. In all cases, however, gross volumetric erosion rates agree with theoretical predictions.

Interactive QR code beautification with full background image embedding

NASA Astrophysics Data System (ADS)

Lin, Lijian; Wu, Song; Liu, Sijiang; Jiang, Bo

2017-06-01

QR (Quick Response) code is a kind of two dimensional barcode that was first developed in automotive industry. Nowadays, QR code has been widely used in commercial applications like product promotion, mobile payment, product information management, etc. Traditional QR codes in accordance with the international standard are reliable and fast to decode, but are lack of aesthetic appearance to demonstrate visual information to customers. In this work, we present a novel interactive method to generate aesthetic QR code. By given information to be encoded and an image to be decorated as full QR code background, our method accepts interactive user's strokes as hints to remove undesired parts of QR code modules based on the support of QR code error correction mechanism and background color thresholds. Compared to previous approaches, our method follows the intention of the QR code designer, thus can achieve more user pleasant result, while keeping high machine readability.

Optimal background matching camouflage.

PubMed

Michalis, Constantine; Scott-Samuel, Nicholas E; Gibson, David P; Cuthill, Innes C

2017-07-12

Background matching is the most familiar and widespread camouflage strategy: avoiding detection by having a similar colour and pattern to the background. Optimizing background matching is straightforward in a homogeneous environment, or when the habitat has very distinct sub-types and there is divergent selection leading to polymorphism. However, most backgrounds have continuous variation in colour and texture, so what is the best solution? Not all samples of the background are likely to be equally inconspicuous, and laboratory experiments on birds and humans support this view. Theory suggests that the most probable background sample (in the statistical sense), at the size of the prey, would, on average, be the most cryptic. We present an analysis, based on realistic assumptions about low-level vision, that estimates the distribution of background colours and visual textures, and predicts the best camouflage. We present data from a field experiment that tests and supports our predictions, using artificial moth-like targets under bird predation. Additionally, we present analogous data for humans, under tightly controlled viewing conditions, searching for targets on a computer screen. These data show that, in the absence of predator learning, the best single camouflage pattern for heterogeneous backgrounds is the most probable sample. © 2017 The Authors.

Universal 'imaginary closed circuit method' and formula for determination of direction of induced emf/current

NASA Astrophysics Data System (ADS)

Balaram Atram, Dattatraya

2011-01-01

Fleming's right-hand rule and the right-flat-hand rule are generally applied for determining the direction of flow of induced emf/current in straight conductors. The right-hand-fingers rule is applied for coils only. The right-hand-thumb rule can be applied for either straight conductors or coils. Different rules have to be applied for different situations. Also, a formula for determining the direction of induced emf/current does not exist on the basis of these rules. In this article, based on Faraday's law of electromagnetic induction and Lenz's law, an 'imaginary closed circuit method' and a formula for determination of direction of induced emf/current has been proposed. The method is universal in the sense that it is applicable for conductors of any shape, for any kind of relative motion of the conductor with respect to the magnetic flux, and moreover it is applicable for the case of varying magnetic flux.

A Method to Simultaneously Detect the Current Sensor Fault and Estimate the State of Energy for Batteries in Electric Vehicles.

PubMed

Xu, Jun; Wang, Jing; Li, Shiying; Cao, Binggang

2016-08-19

Recently, State of energy (SOE) has become one of the most fundamental parameters for battery management systems in electric vehicles. However, current information is critical in SOE estimation and current sensor is usually utilized to obtain the latest current information. However, if the current sensor fails, the SOE estimation may be confronted with large error. Therefore, this paper attempts to make the following contributions: Current sensor fault detection and SOE estimation method is realized simultaneously. Through using the proportional integral observer (PIO) based method, the current sensor fault could be accurately estimated. By taking advantage of the accurate estimated current sensor fault, the influence caused by the current sensor fault can be eliminated and compensated. As a result, the results of the SOE estimation will be influenced little by the fault. In addition, the simulation and experimental workbench is established to verify the proposed method. The results indicate that the current sensor fault can be estimated accurately. Simultaneously, the SOE can also be estimated accurately and the estimation error is influenced little by the fault. The maximum SOE estimation error is less than 2%, even though the large current error caused by the current sensor fault still exists.

Inrush Current Suppression Circuit and Method for Controlling When a Load May Be Fully Energized

NASA Technical Reports Server (NTRS)

Schwerman, Paul (Inventor)

2017-01-01

A circuit and method for controlling when a load may be fully energized includes directing electrical current through a current limiting resistor that has a first terminal connected to a source terminal of a field effect transistor (FET), and a second terminal connected to a drain terminal of the FET. The gate voltage magnitude on a gate terminal of the FET is varied, whereby current flow through the FET is increased while current flow through the current limiting resistor is simultaneously decreased. A determination is made as to when the gate voltage magnitude on the gate terminal is equal to or exceeds a predetermined reference voltage magnitude, and the load is enabled to be fully energized when the gate voltage magnitude is equal to or exceeds the predetermined reference voltage magnitude.

Dips in the diffuse supernova neutrino background

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

Farzan, Yasaman; Palomares-Ruiz, Sergio, E-mail: yasaman@theory.ipm.ac.ir, E-mail: Sergio.Palomares.Ruiz@ific.uv.es

2014-06-01

Scalar (fermion) dark matter with mass in the MeV range coupled to ordinary neutrinos and another fermion (scalar) is motivated by scenarios that establish a link between radiatively generated neutrino masses and the dark matter relic density. With such a coupling, cosmic supernova neutrinos, on their way to us, could resonantly interact with the background dark matter particles, giving rise to a dip in their redshift-integrated spectra. Current and future neutrino detectors, such as Super-Kamiokande, LENA and Hyper-Kamiokande, could be able to detect this distortion.

Low-background detector arrays for infrared astronomy

NASA Technical Reports Server (NTRS)

Mccreight, C. R.; Estrada, J. A.; Goebel, J. H.; Mckelvey, M. E.; Mckibbin, D. D.; Mcmurray, R. E., Jr.; Weber, T. T.

1989-01-01

The status of a program which develops and characterizes integrated infrared (IR) detector array technology for space astronomical applications is described. The devices under development include intrinsic, extrinsic silicon, and extrinsic germanium detectors, coupled to silicon readout electronics. Low-background laboratory test results include measurements of responsivity, noise, dark current, temporal response, and the effects of gamma-radiation. In addition, successful astronomical imagery has been obtained on some arrays from this program. These two aspects of the development combine to demonstrate the strong potential for integrated array technology for IR space astronomy.

Probing Inflation via Cosmic Microwave Background Polarimetry

NASA Technical Reports Server (NTRS)

Chuss, David T.

2008-01-01

The Cosmic Microwave Background (CMB) has been a rich source of information about the early Universe. Detailed measurements of its spectrum and spatial distribution have helped solidify the Standard Model of Cosmology. However, many questions still remain. Standard Cosmology does not explain why the early Universe is geometrically flat, expanding, homogenous across the horizon, and riddled with a small anisotropy that provides the seed for structure formation. Inflation has been proposed as a mechanism that naturally solves these problems. In addition to solving these problems, inflation is expected to produce a spectrum of gravitational waves that will create a particular polarization pattern on the CMB. Detection of this polarized signal is a key test of inflation and will give a direct measurement of the energy scale at which inflation takes place. This polarized signature of inflation is expected to be -9 orders of magnitude below the 2.7 K monopole level of the CMB. This measurement will require good control of systematic errors, an array of many detectors having the requisite sensitivity, and a reliable method for removing polarized foregrounds, and nearly complete sky coverage. Ultimately, this measurement is likely to require a space mission. To this effect, technology and mission concept development are currently underway.

Home and Health in the Third Age — Methodological Background and Descriptive Findings

PubMed Central

Kylén, Maya; Ekström, Henrik; Haak, Maria; Elmståhl, Sölve; Iwarsson, Susanne

2014-01-01

Background: The understanding of the complex relationship between the home environment, well-being and daily functioning in the third age is currently weak. The aim of this paper is to present the methodological background of the Home and Health in the Third Age Study, and describe a sample of men and women in relation to their home and health situation. Methods and Design: The study sample included 371 people aged 67–70, living in ordinary housing in the south of Sweden. Structured interviews and observations were conducted to collect data about objective and perceived aspects of home and health. Results: The majority of the participants were in good health and had few functional limitations. Women had more functional limitations and reported more symptoms than men. Environmental barriers were found in every home investigated; the most were found in the kitchen and hygiene area. Environmental barriers were more common in multi-family than in one-family dwellings. Discussion: This study will increase our knowledge on home and health dynamics among people in the third age. The results have potential to contribute to societal planning related to housing provision, home care and social services for senior citizens. PMID:25019267

Amplification due to two-stream instability of self-electric and magnetic fields of an ion beam propagating in background plasma

NASA Astrophysics Data System (ADS)

Tokluoglu, Erinc K.; Kaganovich, Igor D.; Carlsson, Johan A.; Hara, Kentaro; Startsev, Edward A.

2018-05-01

Propagation of charged particle beams in background plasma as a method of space charge neutralization has been shown to achieve a high degree of charge and current neutralization and therefore enables nearly ballistic propagation and focusing of charged particle beams. Correspondingly, the use of plasmas for propagation of charged particle beams has important applications for transport and focusing of intense particle beams in inertial fusion and high energy density laboratory plasma physics. However, the streaming of beam ions through a background plasma can lead to the development of two-stream instability between the beam ions and the plasma electrons. The beam electric and magnetic fields enhanced by the two-stream instability can lead to defocusing of the ion beam. Using particle-in-cell simulations, we study the scaling of the instability-driven self-electromagnetic fields and consequent defocusing forces with the background plasma density and beam ion mass. We identify plasma parameters where the defocusing forces can be reduced.

Obtaining source current density related to irregularly structured electromagnetic target field inside human body using hybrid inverse/FDTD method.

PubMed

Han, Jijun; Yang, Deqiang; Sun, Houjun; Xin, Sherman Xuegang

2017-01-01

Inverse method is inherently suitable for calculating the distribution of source current density related with an irregularly structured electromagnetic target field. However, the present form of inverse method cannot calculate complex field-tissue interactions. A novel hybrid inverse/finite-difference time domain (FDTD) method that can calculate the complex field-tissue interactions for the inverse design of source current density related with an irregularly structured electromagnetic target field is proposed. A Huygens' equivalent surface is established as a bridge to combine the inverse and FDTD method. Distribution of the radiofrequency (RF) magnetic field on the Huygens' equivalent surface is obtained using the FDTD method by considering the complex field-tissue interactions within the human body model. The obtained magnetic field distributed on the Huygens' equivalent surface is regarded as the next target. The current density on the designated source surface is derived using the inverse method. The homogeneity of target magnetic field and specific energy absorption rate are calculated to verify the proposed method.

[Nutritional status of adults with cystic fibrosis - current methods of assessment].

PubMed

Szabla, Anna; Skorupa, Wojciech; Milewska, Magdalena; Weker, Halina

2015-11-01

Cystic fibrosis (CF) is one of the most frequent monogenic disease in the Caucasian population, inherited in an autosomal recessive pattern. This is a multiple organ disease and its main manifestations include pulmonary and gastrointestinal dysfunction. The exocrine pancreatic deficiency results in impaired digestion and absorption what may lead to malnutrition and vitamins and minerals deficiencies. The life expectancy of cystic fibrosis patients has been increasing over the past years, so there is a need to verify usefulness of existing or create new methods of nutritional status assessment. The aim of this paper was presentation current data on the methods of assessment and monitoring of nutritional status. Particular attention has been paid to appropriate nutritional support in prevention and treatment of malnutrition patients with cystic fibrosis. On the basis of recent literature we can conclude that the advanced nutritional status assessment is recommended in patient with CF by using anthropometrical methods, body composition analysis and biochemical data. Good nutritional status is connected with pulmonary functions, quality and life length. © 2015 MEDPRESS.

Neuronal current detection with low-field magnetic resonance: simulations and methods.

PubMed

Cassará, Antonino Mario; Maraviglia, Bruno; Hartwig, Stefan; Trahms, Lutz; Burghoff, Martin

2009-10-01

The noninvasive detection of neuronal currents in active brain networks [or direct neuronal imaging (DNI)] by means of nuclear magnetic resonance (NMR) remains a scientific challenge. Many different attempts using NMR scanners with magnetic fields >1 T (high-field NMR) have been made in the past years to detect phase shifts or magnitude changes in the NMR signals. However, the many physiological (i.e., the contemporarily BOLD effect, the weakness of the neuronal-induced magnetic field, etc.) and technical limitations (e.g., the spatial resolution) in observing the weak signals have led to some contradicting results. In contrast, only a few attempts have been made using low-field NMR techniques. As such, this paper was aimed at reviewing two recent developments in this front. The detection schemes discussed in this manuscript, the resonant mechanism (RM) and the DC method, are specific to NMR instrumentations with main fields below the earth magnetic field (50 microT), while some even below a few microteslas (ULF-NMR). However, the experimental validation for both techniques, with differentiating sensitivity to the various neuronal activities at specific temporal and spatial resolutions, is still in progress and requires carefully designed magnetic field sensor technology. Additional care should be taken to ensure a stringent magnetic shield from the ambient magnetic field fluctuations. In this review, we discuss the characteristics and prospect of these two methods in detecting neuronal currents, along with the technical requirements on the instrumentation.

A quantitative comparison of two methods to correct eddy current-induced distortions in DT-MRI.

PubMed

Muñoz Maniega, Susana; Bastin, Mark E; Armitage, Paul A

2007-04-01

Eddy current-induced geometric distortions of single-shot, diffusion-weighted, echo-planar (DW-EP) images are a major confounding factor to the accurate determination of water diffusion parameters in diffusion tensor MRI (DT-MRI). Previously, it has been suggested that these geometric distortions can be removed from brain DW-EP images using affine transformations determined from phantom calibration experiments using iterative cross-correlation (ICC). Since this approach was first described, a number of image-based registration methods have become available that can also correct eddy current-induced distortions in DW-EP images. However, as yet no study has investigated whether separate eddy current calibration or image-based registration provides the most accurate way of removing these artefacts from DT-MRI data. Here we compare how ICC phantom calibration and affine FLIRT (http://www.fmrib.ox.ac.uk), a popular image-based multi-modal registration method that can correct both eddy current-induced distortions and bulk subject motion, perform when registering DW-EP images acquired with different slice thicknesses (2.8 and 5 mm) and b-values (1000 and 3000 s/mm(2)). With the use of consistency testing, it was found that ICC was a more robust algorithm for correcting eddy current-induced distortions than affine FLIRT, especially at high b-value and small slice thickness. In addition, principal component analysis demonstrated that the combination of ICC phantom calibration (to remove eddy current-induced distortions) with rigid body FLIRT (to remove bulk subject motion) provided a more accurate registration of DT-MRI data than that achieved by affine FLIRT.

Development of criteria used to establish a background environmental monitoring station

DOE PAGES

Fritz, Brad G.; Barnett, J. Matthew; Snyder, Sandra F.; ...

2015-03-02

It is generally considered necessary to measure concentrations of contaminants-of-concern at a background location when conducting atmospheric environmental surveillance. This is because it is recognized that measurements of background concentrations can enhance interpretation of environmental monitoring data. Despite the recognized need for background measurements, there is little published guidance available that describes how to identify an appropriate atmospheric background monitoring location. This paper develops generic criteria that can guide the decision making process for identifying suitable locations for background atmospheric monitoring station. Detailed methods for evaluating some of these criteria are also provided and a case study for establishment ofmore » an atmospheric background surveillance station as part of an environmental surveillance program is described. While the case study focuses on monitoring for radionuclides, the approach is equally valid for any airborne constituent being monitored. The case study shows that implementation of the developed criteria can result in a good, defensible choice for a background atmospheric monitoring location.« less

Background sources at PEP

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

Lynch, H.; Schwitters, R.F.; Toner, W.T.

Important sources of background for PEP experiments are studied. Background particles originate from high-energy electrons and positrons which have been lost from stable orbits, ..gamma..-rays emitted by the primary beams through bremsstrahlung in the residual gas, and synchrotron radiation x-rays. The effect of these processes on the beam lifetime are calculated and estimates of background rates at the interaction region are given. Recommendations for the PEP design, aimed at minimizing background are presented. 7 figs., 4 tabs.

Assessment of ambient background concentrations of elements in soil using combined survey and open-source data.

PubMed

Mikkonen, Hannah G; Clarke, Bradley O; Dasika, Raghava; Wallis, Christian J; Reichman, Suzie M

2017-02-15

Understanding ambient background concentrations in soil, at a local scale, is an essential part of environmental risk assessment. Where high resolution geochemical soil surveys have not been undertaken, soil data from alternative sources, such as environmental site assessment reports, can be used to support an understanding of ambient background conditions. Concentrations of metals/metalloids (As, Mn, Ni, Pb and Zn) were extracted from open-source environmental site assessment reports, for soils derived from the Newer Volcanics basalt, of Melbourne, Victoria, Australia. A manual screening method was applied to remove samples that were indicated to be contaminated by point sources and hence not representative of ambient background conditions. The manual screening approach was validated by comparison to data from a targeted background soil survey. Statistical methods for exclusion of contaminated samples from background soil datasets were compared to the manual screening method. The statistical methods tested included the Median plus Two Median Absolute Deviations, the upper whisker of a normal and log transformed Tukey boxplot, the point of inflection on a cumulative frequency plot and the 95th percentile. We have demonstrated that where anomalous sample results cannot be screened using site information, the Median plus Two Median Absolute Deviations is a conservative method for derivation of ambient background upper concentration limits (i.e. expected maximums). The upper whisker of a boxplot and the point of inflection on a cumulative frequency plot, were also considered adequate methods for deriving ambient background upper concentration limits, where the percentage of contaminated samples is <25%. Median ambient background concentrations of metals/metalloids in the Newer Volcanic soils of Melbourne were comparable to ambient background concentrations in Europe and the United States, except for Ni, which was naturally enriched in the basalt-derived soils of

Evaluation of counting methods for oceanic radium-228

NASA Astrophysics Data System (ADS)

Orr, James C.

1988-07-01

Measurement of open ocean 228Ra is difficult, typically requiring at least 200 L of seawater. The burden of collecting and processing these large-volume samples severely limits the widespread use of this promising tracer. To use smaller-volume samples, a more sensitive means of analysis is required. To seek out new and improved counting method(s), conventional 228Ra counting methods have been compared with some promising techniques which are currently used for other radionuclides. Of the conventional methods, α spectrometry possesses the highest efficiency (3-9%) and lowest background (0.0015 cpm), but it suffers from the need for complex chemical processing after sampling and the need to allow about 1 year for adequate ingrowth of 228Th granddaughter. The other two conventional counting methods measure the short-lived 228Ac daughter while it remains supported by 228Ra, thereby avoiding the complex sample processing and the long delay before counting. The first of these, high-resolution γ spectrometry, offers the simplest processing and an efficiency (4.8%) comparable to α spectrometry; yet its high background (0.16 cpm) and substantial equipment cost (˜30,000) limit its widespread use. The second no-wait method, β-γ coincidence spectrometry, also offers comparable efficiency (5.3%), but it possesses both lower background (0.0054 cpm) and lower initial cost (˜12,000). Three new (i.e., untried for 228Ra) techniques all seem to promise about a fivefold increase in efficiency over conventional methods. By employing liquid scintillation methods, both α spectrometry and β-γ coincidence spectrometry can improve their counter efficiency while retaining low background. The third new 228Ra counting method could be adapted from a technique which measures 224Ra by 220Rn emanation. After allowing for ingrowth and then counting for the 224Ra great-granddaughter, 228Ra could be back calculated, thereby yielding a method with high efficiency, where no sample processing

Reducing DRIFT backgrounds with a submicron aluminized-mylar cathode

NASA Astrophysics Data System (ADS)

Battat, J. B. R.; Daw, E.; Dorofeev, A.; Ezeribe, A. C.; Fox, J. R.; Gauvreau, J.-L.; Gold, M.; Harmon, L.; Harton, J.; Lafler, R.; Landers, J.; Lauer, R. J.; Lee, E. R.; Loomba, D.; Lumnah, A.; Matthews, J.; Miller, E. H.; Mouton, F.; Murphy, A. St. J.; Paling, S. M.; Phan, N.; Sadler, S. W.; Scarff, A.; Schuckman, F. G.; Snowden-Ifft, D.; Spooner, N. J. C.; Walker, D.

2015-09-01

Background events in the DRIFT-IId dark matter detector, mimicking potential WIMP signals, are predominantly caused by alpha decays on the central cathode in which the alpha particle is completely or partially absorbed by the cathode material. We installed a 0.9 μm thick aluminized-mylar cathode as a way to reduce the probability of producing these backgrounds. We study three generations of cathode (wire, thin-film, and radiologically clean thin-film) with a focus on the ratio of background events to alpha decays. Two independent methods of measuring the absolute alpha decay rate are used to ensure an accurate result, and agree to within 10%. Using alpha range spectroscopy, we measure the radiologically cleanest cathode version to have a contamination of 3.3±0.1 ppt 234U and 73±2 ppb 238U. This cathode reduces the probability of producing an RPR from an alpha decay by a factor of 70±20 compared to the original stainless steel wire cathode. First results are presented from a texturized version of the cathode, intended to be even more transparent to alpha particles. These efforts, along with other background reduction measures, have resulted in a drop in the observed background rate from 500/day to 1/day. With the recent implementation of full-volume fiducialization, these remaining background events are identified, allowing for background-free operation.

Current measurement apparatus

DOEpatents

Umans, Stephen D.

2008-11-11

Apparatus and methods are provided for a system for measurement of a current in a conductor such that the conductor current may be momentarily directed to a current measurement element in order to maintain proper current without significantly increasing an amount of power dissipation attributable to the current measurement element or adding resistance to assist in current measurement. The apparatus and methods described herein are useful in superconducting circuits where it is necessary to monitor current carried by the superconducting elements while minimizing the effects of power dissipation attributable to the current measurement element.

The value of value of information: best informing research design and prioritization using current methods.

PubMed

Eckermann, Simon; Karnon, Jon; Willan, Andrew R

2010-01-01

Value of information (VOI) methods have been proposed as a systematic approach to inform optimal research design and prioritization. Four related questions arise that VOI methods could address. (i) Is further research for a health technology assessment (HTA) potentially worthwhile? (ii) Is the cost of a given research design less than its expected value? (iii) What is the optimal research design for an HTA? (iv) How can research funding be best prioritized across alternative HTAs? Following Occam's razor, we consider the usefulness of VOI methods in informing questions 1-4 relative to their simplicity of use. Expected value of perfect information (EVPI) with current information, while simple to calculate, is shown to provide neither a necessary nor a sufficient condition to address question 1, given that what EVPI needs to exceed varies with the cost of research design, which can vary from very large down to negligible. Hence, for any given HTA, EVPI does not discriminate, as it can be large and further research not worthwhile or small and further research worthwhile. In contrast, each of questions 1-4 are shown to be fully addressed (necessary and sufficient) where VOI methods are applied to maximize expected value of sample information (EVSI) minus expected costs across designs. In comparing complexity in use of VOI methods, applying the central limit theorem (CLT) simplifies analysis to enable easy estimation of EVSI and optimal overall research design, and has been shown to outperform bootstrapping, particularly with small samples. Consequently, VOI methods applying the CLT to inform optimal overall research design satisfy Occam's razor in both improving decision making and reducing complexity. Furthermore, they enable consideration of relevant decision contexts, including option value and opportunity cost of delay, time, imperfect implementation and optimal design across jurisdictions. More complex VOI methods such as bootstrapping of the expected value of

Method for technology-delivered healthcare measures.

PubMed

Kramer-Jackman, Kelli Lee; Popkess-Vawter, Sue

2011-12-01

Current healthcare literature lacks development and evaluation methods for research and practice measures administered by technology. Researchers with varying levels of informatics experience are developing technology-delivered measures because of the numerous advantages they offer. Hasty development of technology-delivered measures can present issues that negatively influence administration and psychometric properties. The Method for Technology-delivered Healthcare Measures is designed to systematically guide the development and evaluation of technology-delivered measures. The five-step Method for Technology-delivered Healthcare Measures includes establishment of content, e-Health literacy, technology delivery, expert usability, and participant usability. Background information and Method for Technology-delivered Healthcare Measures steps are detailed.

Spin Currents and Ferromagnetic Resonance in Magnetic Thin Films

NASA Astrophysics Data System (ADS)

Ellsworth, David

Spin currents represent a new and exciting phenomenon. There is both a wealth of new physics to be discovered and understood, and many appealing devices which may result from this area of research. To fully realize the potential of this discipline it is necessary to develop new methods for realizing spin currents and explore new materials which may be suitable for spin current applications. Spin currents are an inherently dynamic phenomenon involving the transfer of angular momentum within and between different thin films. In order to understand and optimize such devices the dynamics of magnetization must be determined. This dissertation reports on novel approaches for spin current generation utilizing the magnetic insulators yttrium iron garnet (YIG) and M-type barium hexagonal ferrite (BaM). First, the light-induced spin Seebeck effect is reported for the first time in YIG. Additionally, the first measurement of the spin Seebeck effect without an external magnetic field is demonstrated. To accomplish this the self-biased BaM thin films are utilized. Second, a new method for the generation of spin currents is presented: the photo-spin-voltaic effect. In this new phenomenon, a spin current may be generated by photons in a non-magnetic metal that is in close proximity to a magnetic insulator. On exposure to light, there occurs a light induced, spin-dependent excitation of electrons in a few platinum layers near the metal/magnetic insulator interface. This excitation gives rise to a pure spin current which flows in the metal. This new effect is explored in detail and extensive measurements are carried out to confirm the photonic origin of the photo-spin-voltaic effect and exclude competing effects. In addition to the spin current measurements, magnetization dynamics were probed in thin films using ferromagnetic resonance (FMR). In order to determine the optimal material configuration for magnetic recording write heads, FMR measurements were used to perform damping

A Method to Simultaneously Detect the Current Sensor Fault and Estimate the State of Energy for Batteries in Electric Vehicles

PubMed Central

Xu, Jun; Wang, Jing; Li, Shiying; Cao, Binggang

2016-01-01

Recently, State of energy (SOE) has become one of the most fundamental parameters for battery management systems in electric vehicles. However, current information is critical in SOE estimation and current sensor is usually utilized to obtain the latest current information. However, if the current sensor fails, the SOE estimation may be confronted with large error. Therefore, this paper attempts to make the following contributions: Current sensor fault detection and SOE estimation method is realized simultaneously. Through using the proportional integral observer (PIO) based method, the current sensor fault could be accurately estimated. By taking advantage of the accurate estimated current sensor fault, the influence caused by the current sensor fault can be eliminated and compensated. As a result, the results of the SOE estimation will be influenced little by the fault. In addition, the simulation and experimental workbench is established to verify the proposed method. The results indicate that the current sensor fault can be estimated accurately. Simultaneously, the SOE can also be estimated accurately and the estimation error is influenced little by the fault. The maximum SOE estimation error is less than 2%, even though the large current error caused by the current sensor fault still exists. PMID:27548183

A systematic analysis of the XMM-Newton background: III. Impact of the magnetospheric environment

NASA Astrophysics Data System (ADS)

Ghizzardi, Simona; Marelli, Martino; Salvetti, David; Gastaldello, Fabio; Molendi, Silvano; De Luca, Andrea; Moretti, Alberto; Rossetti, Mariachiara; Tiengo, Andrea

2017-12-01

A detailed characterization of the particle induced background is fundamental for many of the scientific objectives of the Athena X-ray telescope, thus an adequate knowledge of the background that will be encountered by Athena is desirable. Current X-ray telescopes have shown that the intensity of the particle induced background can be highly variable. Different regions of the magnetosphere can have very different environmental conditions, which can, in principle, differently affect the particle induced background detected by the instruments. We present results concerning the influence of the magnetospheric environment on the background detected by EPIC instrument onboard XMM-Newton through the estimate of the variation of the in-Field-of-View background excess along the XMM-Newton orbit. An important contribution to the XMM background, which may affect the Athena background as well, comes from soft proton flares. Along with the flaring component a low-intensity component is also present. We find that both show modest variations in the different magnetozones and that the soft proton component shows a strong trend with the distance from Earth.

Current Methods in the Molecular Typing of Mycobacterium tuberculosis and Other Mycobacteria

PubMed Central

van Ingen, Jakko; Dziadek, Jarosław; Mazur, Paweł K.; Bielecki, Jacek

2014-01-01

In the epidemiology of tuberculosis (TB) and nontuberculous mycobacterial (NTM) diseases, as in all infectious diseases, the key issue is to define the source of infection and to disclose its routes of transmission and dissemination in the environment. For this to be accomplished, the ability of discerning and tracking individual Mycobacterium strains is of critical importance. Molecular typing methods have greatly improved our understanding of the biology of mycobacteria and provide powerful tools to combat the diseases caused by these pathogens. The utility of various typing methods depends on the Mycobacterium species under investigation as well as on the research question. For tuberculosis, different methods have different roles in phylogenetic analyses and person-to-person transmission studies. In NTM diseases, most investigations involve the search for environmental sources or phylogenetic relationships. Here, too, the type of setting determines which methodology is most suitable. Within this review, we summarize currently available molecular methods for strain typing of M. tuberculosis and some NTM species, most commonly associated with human disease. For the various methods, technical practicalities as well as discriminatory power and accomplishments are reviewed. PMID:24527454

Inverse current source density method in two dimensions: inferring neural activation from multielectrode recordings.

PubMed

Łęski, Szymon; Pettersen, Klas H; Tunstall, Beth; Einevoll, Gaute T; Gigg, John; Wójcik, Daniel K

2011-12-01

The recent development of large multielectrode recording arrays has made it affordable for an increasing number of laboratories to record from multiple brain regions simultaneously. The development of analytical tools for array data, however, lags behind these technological advances in hardware. In this paper, we present a method based on forward modeling for estimating current source density from electrophysiological signals recorded on a two-dimensional grid using multi-electrode rectangular arrays. This new method, which we call two-dimensional inverse Current Source Density (iCSD 2D), is based upon and extends our previous one- and three-dimensional techniques. We test several variants of our method, both on surrogate data generated from a collection of Gaussian sources, and on model data from a population of layer 5 neocortical pyramidal neurons. We also apply the method to experimental data from the rat subiculum. The main advantages of the proposed method are the explicit specification of its assumptions, the possibility to include system-specific information as it becomes available, the ability to estimate CSD at the grid boundaries, and lower reconstruction errors when compared to the traditional approach. These features make iCSD 2D a substantial improvement over the approaches used so far and a powerful new tool for the analysis of multielectrode array data. We also provide a free GUI-based MATLAB toolbox to analyze and visualize our test data as well as user datasets.

Decoding of Ankle Flexion and Extension from Cortical Current Sources Estimated from Non-invasive Brain Activity Recording Methods.

PubMed

Mejia Tobar, Alejandra; Hyoudou, Rikiya; Kita, Kahori; Nakamura, Tatsuhiro; Kambara, Hiroyuki; Ogata, Yousuke; Hanakawa, Takashi; Koike, Yasuharu; Yoshimura, Natsue

2017-01-01

The classification of ankle movements from non-invasive brain recordings can be applied to a brain-computer interface (BCI) to control exoskeletons, prosthesis, and functional electrical stimulators for the benefit of patients with walking impairments. In this research, ankle flexion and extension tasks at two force levels in both legs, were classified from cortical current sources estimated by a hierarchical variational Bayesian method, using electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) recordings. The hierarchical prior for the current source estimation from EEG was obtained from activated brain areas and their intensities from an fMRI group (second-level) analysis. The fMRI group analysis was performed on regions of interest defined over the primary motor cortex, the supplementary motor area, and the somatosensory area, which are well-known to contribute to movement control. A sparse logistic regression method was applied for a nine-class classification (eight active tasks and a resting control task) obtaining a mean accuracy of 65.64% for time series of current sources, estimated from the EEG and the fMRI signals using a variational Bayesian method, and a mean accuracy of 22.19% for the classification of the pre-processed of EEG sensor signals, with a chance level of 11.11%. The higher classification accuracy of current sources, when compared to EEG classification accuracy, was attributed to the high number of sources and the different signal patterns obtained in the same vertex for different motor tasks. Since the inverse filter estimation for current sources can be done offline with the present method, the present method is applicable to real-time BCIs. Finally, due to the highly enhanced spatial distribution of current sources over the brain cortex, this method has the potential to identify activation patterns to design BCIs for the control of an affected limb in patients with stroke, or BCIs from motor imagery in patients

Background Selection in Partially Selfing Populations

PubMed Central

Roze, Denis

2016-01-01

Self-fertilizing species often present lower levels of neutral polymorphism than their outcrossing relatives. Indeed, selfing automatically increases the rate of coalescence per generation, but also enhances the effects of background selection and genetic hitchhiking by reducing the efficiency of recombination. Approximations for the effect of background selection in partially selfing populations have been derived previously, assuming tight linkage between deleterious alleles and neutral loci. However, loosely linked deleterious mutations may have important effects on neutral diversity in highly selfing populations. In this article, I use a general method based on multilocus population genetics theory to express the effect of a deleterious allele on diversity at a linked neutral locus in terms of moments of genetic associations between loci. Expressions for these genetic moments at equilibrium are then computed for arbitrary rates of selfing and recombination. An extrapolation of the results to the case where deleterious alleles segregate at multiple loci is checked using individual-based simulations. At high selfing rates, the tight linkage approximation underestimates the effect of background selection in genomes with moderate to high map length; however, another simple approximation can be obtained for this situation and provides accurate predictions as long as the deleterious mutation rate is not too high. PMID:27075726

Cosmic microwave background power asymmetry from non-Gaussian modulation.

PubMed

Schmidt, Fabian; Hui, Lam

2013-01-04

Non-Gaussianity in the inflationary perturbations can couple observable scales to modes of much longer wavelength (even superhorizon), leaving as a signature a large-angle modulation of the observed cosmic microwave background power spectrum. This provides an alternative origin for a power asymmetry that is otherwise often ascribed to a breaking of statistical isotropy. The non-Gaussian modulation effect can be significant even for typical ~10(-5) perturbations while respecting current constraints on non-Gaussianity if the squeezed limit of the bispectrum is sufficiently infrared divergent. Just such a strongly infrared-divergent bispectrum has been claimed for inflation models with a non-Bunch-Davies initial state, for instance. Upper limits on the observed cosmic microwave background power asymmetry place stringent constraints on the duration of inflation in such models.

Extending the Li&Ma method to include PSF information

NASA Astrophysics Data System (ADS)

Nievas-Rosillo, M.; Contreras, J. L.

2016-02-01

The so called Li&Ma formula is still the most frequently used method for estimating the significance of observations carried out by Imaging Atmospheric Cherenkov Telescopes. In this work a straightforward extension of the method for point sources that profits from the good imaging capabilities of current instruments is proposed. It is based on a likelihood ratio under the assumption of a well-known PSF and a smooth background. Its performance is tested with Monte Carlo simulations based on real observations and its sensitivity is compared to standard methods which do not incorporate PSF information. The gain of significance that can be attributed to the inclusion of the PSF is around 10% and can be boosted if a background model is assumed or a finer binning is used.

Current methods and attitudes of women towards contraception in Europe and America.

PubMed

Johnson, Sarah; Pion, Christine; Jennings, Victoria

2013-02-05

The choice of available contraceptive methods has increased in recent years; however, recent data on women's awareness of methods and reasons for their method choice, or reasons for changing methods, is limited. The aim of this study was to examine the use and awareness of contraceptive methods in the USA, UK, Germany, Italy and Spain. Quantitative survey of heterosexual women aged 25-44 years (n=2544), with no known infertility. Questions related to knowledge and use of contraceptive methods, reasons for choice and for changing methods, and sources of advice. There was generally good awareness of most forms of contraception in all five countries. Awareness and current usage was greatest for the contraceptive pill (awareness >98%, usage varied from 35% [Spain] to 63% [Germany]); and male condom (awareness >95%, usage varied from 20% [Germany] to 47% [Spain]); awareness of other methods varied between countries. Doctors have the greatest influence on women's choice of contraceptive method (>50% for all countries), and are most likely to suggest the contraceptive pill or male condom.Women's contraceptive needs change; 4-36% of contraceptive pill users were likely to change their method within 12 months. For previous contraceptive pill users (n=377), most common reason for change was concern about side effects (from 26% [Italy] to 10% [UK]); however, awareness of many non-hormonal contraceptive methods was low. Women aged 25-44 are aware of a wide variety of contraceptive methods, but knowledge and usage of the contraceptive pill and condoms predominates. Changing contraception method is frequent, occurring for a variety of reasons, including change in life circumstances and, for pill users, concerns about side effects.

Autonomous Method and System for Minimizing the Magnitude of Plasma Discharge Current Oscillations in a Hall Effect Plasma Device

NASA Technical Reports Server (NTRS)

Hruby, Vladimir (Inventor); Demmons, Nathaniel (Inventor); Ehrbar, Eric (Inventor); Pote, Bruce (Inventor); Rosenblad, Nathan (Inventor)

2014-01-01

An autonomous method for minimizing the magnitude of plasma discharge current oscillations in a Hall effect plasma device includes iteratively measuring plasma discharge current oscillations of the plasma device and iteratively adjusting the magnet current delivered to the plasma device in response to measured plasma discharge current oscillations to reduce the magnitude of the plasma discharge current oscillations.

New window into stochastic gravitational wave background.

PubMed

Rotti, Aditya; Souradeep, Tarun

2012-11-30

A stochastic gravitational wave background (SGWB) would gravitationally lens the cosmic microwave background (CMB) photons. We correct the results provided in existing literature for modifications to the CMB polarization power spectra due to lensing by gravitational waves. Weak lensing by gravitational waves distorts all four CMB power spectra; however, its effect is most striking in the mixing of power between the E mode and B mode of CMB polarization. This suggests the possibility of using measurements of the CMB angular power spectra to constrain the energy density (Ω(GW)) of the SGWB. Using current data sets (QUAD, WMAP, and ACT), we find that the most stringent constraints on the present Ω(GW) come from measurements of the angular power spectra of CMB temperature anisotropies. In the near future, more stringent bounds on Ω(GW) can be expected with improved upper limits on the B modes of CMB polarization. Any detection of B modes of CMB polarization above the expected signal from large scale structure lensing could be a signal for a SGWB.

Possibilities of Processing Archival Photogrammetric Images Captured by Rollei 6006 Metric Camera Using Current Method

NASA Astrophysics Data System (ADS)

Dlesk, A.; Raeva, P.; Vach, K.

2018-05-01

Processing of analog photogrammetric negatives using current methods brings new challenges and possibilities, for example, creation of a 3D model from archival images which enables the comparison of historical state and current state of cultural heritage objects. The main purpose of this paper is to present possibilities of processing archival analog images captured by photogrammetric camera Rollei 6006 metric. In 1994, the Czech company EuroGV s.r.o. carried out photogrammetric measurements of former limestone quarry the Great America located in the Central Bohemian Region in the Czech Republic. All the negatives of photogrammetric images, complete documentation, coordinates of geodetically measured ground control points, calibration reports and external orientation of images calculated in the Combined Adjustment Program are preserved and were available for the current processing. Negatives of images were scanned and processed using structure from motion method (SfM). The result of the research is a statement of what accuracy is possible to expect from the proposed methodology using Rollei metric images originally obtained for terrestrial intersection photogrammetry while adhering to the proposed methodology.

Can currently available non-animal methods detect pre and pro-haptens relevant for skin sensitization?

PubMed

Patlewicz, Grace; Casati, Silvia; Basketter, David A; Asturiol, David; Roberts, David W; Lepoittevin, Jean-Pierre; Worth, Andrew P; Aschberger, Karin

2016-12-01

Predictive testing to characterize substances for their skin sensitization potential has historically been based on animal tests such as the Local Lymph Node Assay (LLNA). In recent years, regulations in the cosmetics and chemicals sectors have provided strong impetus to develop non-animal alternatives. Three test methods have undergone OECD validation: the direct peptide reactivity assay (DPRA), the KeratinoSens™ and the human Cell Line Activation Test (h-CLAT). Whilst these methods perform relatively well in predicting LLNA results, a concern raised is their ability to predict chemicals that need activation to be sensitizing (pre- or pro-haptens). This current study reviewed an EURL ECVAM dataset of 127 substances for which information was available in the LLNA and three non-animal test methods. Twenty eight of the sensitizers needed to be activated, with the majority being pre-haptens. These were correctly identified by 1 or more of the test methods. Six substances were categorized exclusively as pro-haptens, but were correctly identified by at least one of the cell-based assays. The analysis here showed that skin metabolism was not likely to be a major consideration for assessing sensitization potential and that sensitizers requiring activation could be identified correctly using one or more of the current non-animal methods. Published by Elsevier Inc.

Experiments on the Expansion of a Dense Plasma into a Background Magnetoplasma

NASA Astrophysics Data System (ADS)

Gekelman, Walter; Vanzeeland, Mike; Vincena, Steve; Pribyl, Pat

2003-10-01

There are many situations, which occur in space (coronal mass ejections, or are man-made (upper atmospheric detonations) as well as the initial stages of a supernovae, in which a dense plasma expands into a background magnetized plasma, that can support Alfvèn waves. The upgraded LArge Plasma Device (LAPD) is a machine, at UCLA, in which Alfvèn wave propagation in homogeneous and inhomogeneous plasmas has been studied. We describe a series of experiments,which involve the expansion of a dense (initially, n_laser-plasma/n_0≫1) laser-produced plasma into an ambient highly magnetized background plasma capable of supporting Alfvèn waves will be presented. The 150 MW laser is pulsed at the same 1 Hz repetition rate as the plasma in a highly reproducible experiment. The interaction results in the production of intense shear Alfvèn waves, as well as large density perturbations. The waves propagate away from the target and are observed to become plasma column resonances. In the initial phase the background magnetic field is expelled from a plasma bubble. Currents in the main body of the plasma are generated to neutralize the positively charged bubble. The current system which results, becomes that of a spectrum of shear Alfvèn waves. Spatial patterns of the wave magnetic fields waves are measured at over 10^4 locations. As the dense plasma expands across the magnetic field it seeds the column with shear waves. Most of the Alfvèn wave energy is in shear waves, which become field line resonances after a machine transit time. The interplay between waves, currents, inductive electric fields and space charge is analyzed in great detail. Dramatic movies of the measured wave fields and their associated currents will be presented. Work supported by ONR, and DOE /NSF.

30 CFR 77.701-1 - Approved methods of grounding of equipment receiving power from ungrounded alternating current...

Code of Federal Regulations, 2013 CFR

2013-07-01

... receiving power from ungrounded alternating current power systems. 77.701-1 Section 77.701-1 Mineral... power systems. For purposes of grounding metallic frames, casings and other enclosures of equipment receiving power from ungrounded alternating current power systems, the following methods of grounding will...

30 CFR 77.701-1 - Approved methods of grounding of equipment receiving power from ungrounded alternating current...

Code of Federal Regulations, 2012 CFR

2012-07-01

... receiving power from ungrounded alternating current power systems. 77.701-1 Section 77.701-1 Mineral... power systems. For purposes of grounding metallic frames, casings and other enclosures of equipment receiving power from ungrounded alternating current power systems, the following methods of grounding will...

30 CFR 77.701-1 - Approved methods of grounding of equipment receiving power from ungrounded alternating current...

Code of Federal Regulations, 2014 CFR

2014-07-01

... receiving power from ungrounded alternating current power systems. 77.701-1 Section 77.701-1 Mineral... power systems. For purposes of grounding metallic frames, casings and other enclosures of equipment receiving power from ungrounded alternating current power systems, the following methods of grounding will...

Conceptual knowledge representation: A cross-section of current research.

PubMed

Rogers, Timothy T; Wolmetz, Michael

2016-01-01

How is conceptual knowledge encoded in the brain? This special issue of Cognitive Neuropsychology takes stock of current efforts to answer this question through a variety of methods and perspectives. Across this work, three questions recur, each fundamental to knowledge representation in the mind and brain. First, what are the elements of conceptual representation? Second, to what extent are conceptual representations embodied in sensory and motor systems? Third, how are conceptual representations shaped by context, especially linguistic context? In this introductory article we provide relevant background on these themes and introduce how they are addressed by our contributing authors.

Method for reducing peak phase current and decreasing staring time for an internal combustion engine having an induction machine

DOEpatents

Amey, David L.; Degner, Michael W.

2002-01-01

A method for reducing the starting time and reducing the peak phase currents for an internal combustion engine that is started using an induction machine starter/alternator. The starting time is reduced by pre-fluxing the induction machine and the peak phase currents are reduced by reducing the flux current command after a predetermined period of time has elapsed and concurrent to the application of the torque current command. The method of the present invention also provides a strategy for anticipating the start command for an internal combustion engine and determines a start strategy based on the start command and the operating state of the internal combustion engine.

The location and recognition of anti-counterfeiting code image with complex background

NASA Astrophysics Data System (ADS)

Ni, Jing; Liu, Quan; Lou, Ping; Han, Ping

2017-07-01

The order of cigarette market is a key issue in the tobacco business system. The anti-counterfeiting code, as a kind of effective anti-counterfeiting technology, can identify counterfeit goods, and effectively maintain the normal order of market and consumers' rights and interests. There are complex backgrounds, light interference and other problems in the anti-counterfeiting code images obtained by the tobacco recognizer. To solve these problems, the paper proposes a locating method based on Susan operator, combined with sliding window and line scanning,. In order to reduce the interference of background and noise, we extract the red component of the image and convert the color image into gray image. For the confusing characters, recognition results correction based on the template matching method has been adopted to improve the recognition rate. In this method, the anti-counterfeiting code can be located and recognized correctly in the image with complex background. The experiment results show the effectiveness and feasibility of the approach.

How Long Is the Shadow? The Relationships of Family Background to Selected Adult Outcomes: Results from PIAAC

ERIC Educational Resources Information Center

Braun, Henry

2018-01-01

Background: Ongoing interest in the relationships between family background and adult outcomes is motivated by concerns regarding the intergenerational transmission of advantage/disadvantage. Currently all countries are far from achieving the ideal that all individuals, irrespective of their starting points or their demographic characteristics,…

Functionally graded polymeric materials: A brif review of current fabrication methods and introduction of a novel fabrication method.

PubMed

Almasi, Davood; Sadeghi, Maliheh; Lau, Woei Jye; Roozbahani, Fatemeh; Iqbal, Nida

2016-07-01

The present work reviews the current fabrication methods of the functionally graded polymeric material (FGPM) and introduces a novel fabrication method that is versatile in applications as compared to those of existing used methods. For the first time electrophoresis was used to control the distribution of the tetracycline hydrochloride (TC) in a film made of polylactic acid (PLA), aiming to induce antimicrobial effect on the film prepared. The elemental analysis on the film surface showed that by employing electrophoresis force, higher amount of TC was detected near the top surface of the film. Results also showed that the FGPM samples with higher percentage of the TC on the film surface were highly effective to minimize the growth of Escherichia coli. These findings are useful and important to improve dispersion quality of the particles in the composite material and further enhance its antibacterial property. Copyright © 2016 Elsevier B.V. All rights reserved.

Gas leak detection in infrared video with background modeling

NASA Astrophysics Data System (ADS)

Zeng, Xiaoxia; Huang, Likun

2018-03-01

Background modeling plays an important role in the task of gas detection based on infrared video. VIBE algorithm is a widely used background modeling algorithm in recent years. However, the processing speed of the VIBE algorithm sometimes cannot meet the requirements of some real time detection applications. Therefore, based on the traditional VIBE algorithm, we propose a fast prospect model and optimize the results by combining the connected domain algorithm and the nine-spaces algorithm in the following processing steps. Experiments show the effectiveness of the proposed method.

Nonrelativistic trace and diffeomorphism anomalies in particle number background

NASA Astrophysics Data System (ADS)

Auzzi, Roberto; Baiguera, Stefano; Nardelli, Giuseppe

2018-04-01

Using the heat kernel method, we compute nonrelativistic trace anomalies for Schrödinger theories in flat spacetime, with a generic background gauge field for the particle number symmetry, both for a free scalar and a free fermion. The result is genuinely nonrelativistic, and it has no counterpart in the relativistic case. Contrary to naive expectations, the anomaly is not gauge invariant; this is similar to the nongauge covariance of the non-Abelian relativistic anomaly. We also show that, in the same background, the gravitational anomaly for a nonrelativistic scalar vanishes.

Innovative real-time and non-destructive method of beam profile measurement under large beam current irradiation for BNCT

NASA Astrophysics Data System (ADS)

Takada, M.; Kamada, S.; Suda, M.; Fujii, R.; Nakamura, M.; Hoshi, M.; Sato, H.; Endo, S.; Hamano, T.; Arai, S.; Higashimata, A.

2012-10-01

We developed a real-time and non-destructive method of beam profile measurement on a target under large beam current irradiation, and without any complex radiation detectors or electrical circuits. We measured the beam profiles on a target by observing the target temperature using an infrared-radiation thermometer camera. The target temperatures were increased and decreased quickly by starting and stopping the beam irradiation within 1 s in response speed. Our method could trace beam movements rapidly. The beam size and position were calibrated by measuring O-ring heat on the target. Our method has the potential to measure beam profiles at beam current over 1 mA for proton and deuteron with the energy around 3 MeV and allows accelerator operators to adjust the beam location during beam irradiation experiments without decreasing the beam current.

Backgrounds in Language.

ERIC Educational Resources Information Center

Maxwell, John C.; Long, Barbara K.

"Backgrounds in Language," a field-tested inservice course designed for use by groups of 15 or 25 language arts teachers, provides the subject matter background teachers need to make informed decisions about what curriculum materials to use in what way, at what time, and with which students. The course is comprised of eight 2-hour sessions,…

Background Adjusted Alignment-Free Dissimilarity Measures Improve the Detection of Horizontal Gene Transfer.

PubMed

Tang, Kujin; Lu, Yang Young; Sun, Fengzhu

2018-01-01

Horizontal gene transfer (HGT) plays an important role in the evolution of microbial organisms including bacteria. Alignment-free methods based on single genome compositional information have been used to detect HGT. Currently, Manhattan and Euclidean distances based on tetranucleotide frequencies are the most commonly used alignment-free dissimilarity measures to detect HGT. By testing on simulated bacterial sequences and real data sets with known horizontal transferred genomic regions, we found that more advanced alignment-free dissimilarity measures such as CVTree and [Formula: see text] that take into account the background Markov sequences can solve HGT detection problems with significantly improved performance. We also studied the influence of different factors such as evolutionary distance between host and donor sequences, size of sliding window, and host genome composition on the performances of alignment-free methods to detect HGT. Our study showed that alignment-free methods can predict HGT accurately when host and donor genomes are in different order levels. Among all methods, CVTree with word length of 3, [Formula: see text] with word length 3, Markov order 1 and [Formula: see text] with word length 4, Markov order 1 outperform others in terms of their highest F 1 -score and their robustness under the influence of different factors.

Isotropy-violation diagnostics for B-mode polarization foregrounds to the Cosmic Microwave Background

NASA Astrophysics Data System (ADS)

Rotti, Aditya; Huffenberger, Kevin

2016-09-01

Isotropy-violation statistics can highlight polarized galactic foregrounds that contaminate primordial B-modes in the Cosmic Microwave Background (CMB). We propose a particular isotropy-violation test and apply it to polarized Planck 353 GHz data, constructing a map that indicates B-mode foreground dust power over the sky. We build our main isotropy test in harmonic space via the bipolar spherical harmonic basis, and our method helps us to identify the least-contaminated directions. By this measure, there are regions of low foreground in and around the BICEP field, near the South Galactic Pole, and in the Northern Galactic Hemisphere. There is also a possible foreground feature in the BICEP field. We compare our results to those based on the local power spectrum, which is computed on discs using a version of the method of Planck Int. XXX (2016). The discs method is closely related to our isotropy-violation diagnostic. We pay special care to the treatment of noise, including chance correlations with the foregrounds. Currently we use our isotropy tool to assess the cleanest portions of the sky, but in the future such methods will allow isotropy-based null tests for foreground contamination in maps purported to measure primordial B-modes, particularly in cases of limited frequency coverage.

Probing the Intergalactic Magnetic Field with the Anisotropy of the Extragalactic Gamma-ray Background

NASA Technical Reports Server (NTRS)

Venters, T. M.; Pavlidou, V.

2013-01-01

The intergalactic magnetic field (IGMF) may leave an imprint on the angular anisotropy of the extragalactic gamma-ray background through its effect on electromagnetic cascades triggered by interactions between very high energy photons and the extragalactic background light. A strong IGMF will deflect secondary particles produced in these cascades and will thus tend to isotropize lower energy cascade photons, thereby inducing a modulation in the anisotropy energy spectrum of the gamma-ray background. Here we present a simple, proof-of-concept calculation of the magnitude of this effect and demonstrate that current Fermi data already seem to prefer nonnegligible IGMF values. The anisotropy energy spectrum of the Fermi gamma-ray background could thus be used as a probe of the IGMF strength.

Chandra ACIS-I particle background: an analytical model

NASA Astrophysics Data System (ADS)

Bartalucci, I.; Mazzotta, P.; Bourdin, H.; Vikhlinin, A.

2014-06-01

Aims: Imaging and spectroscopy of X-ray extended sources require a proper characterisation of a spatially unresolved background signal. This background includes sky and instrumental components, each of which are characterised by its proper spatial and spectral behaviour. While the X-ray sky background has been extensively studied in previous work, here we analyse and model the instrumental background of the ACIS-I detector on board the Chandra X-ray observatory in very faint mode. Methods: Caused by interaction of highly energetic particles with the detector, the ACIS-I instrumental background is spectrally characterised by the superimposition of several fluorescence emission lines onto a continuum. To isolate its flux from any sky component, we fitted an analytical model of the continuum to observations performed in very faint mode with the detector in the stowed position shielded from the sky, and gathered over the eight-year period starting in 2001. The remaining emission lines were fitted to blank-sky observations of the same period. We found 11 emission lines. Analysing the spatial variation of the amplitude, energy and width of these lines has further allowed us to infer that three lines of these are presumably due to an energy correction artefact produced in the frame store. Results: We provide an analytical model that predicts the instrumental background with a precision of 2% in the continuum and 5% in the lines. We use this model to measure the flux of the unresolved cosmic X-ray background in the Chandra deep field south. We obtain a flux of 10.2+0.5-0.4 × 10-13 erg cm-2 deg-2 s-1 for the [1-2] keV band and (3.8 ± 0.2) × 10-12 erg cm-2 deg-2 s-1 for the [2-8] keV band.

Analytical evaluation of current starch methods used in the international sugar industry: Part I.

PubMed

Cole, Marsha; Eggleston, Gillian; Triplett, Alexa

2017-08-01

Several analytical starch methods exist in the international sugar industry to mitigate starch-related processing challenges and assess the quality of traded end-products. These methods use iodometric chemistry, mostly potato starch standards, and utilize similar solubilization strategies, but had not been comprehensively compared. In this study, industrial starch methods were compared to the USDA Starch Research method using simulated raw sugars. Type of starch standard, solubilization approach, iodometric reagents, and wavelength detection affected total starch determination in simulated raw sugars. Simulated sugars containing potato starch were more accurately detected by the industrial methods, whereas those containing corn starch, a better model for sugarcane starch, were only accurately measured by the USDA Starch Research method. Use of a potato starch standard curve over-estimated starch concentrations. Among the variables studied, starch standard, solubilization approach, and wavelength detection affected the sensitivity, accuracy/precision, and limited the detection/quantification of the current industry starch methods the most. Published by Elsevier Ltd.

Background canceling surface alpha detector

DOEpatents

MacArthur, D.W.; Allander, K.S.; Bounds, J.A.

1996-06-11

A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone. 5 figs.

Background canceling surface alpha detector

DOEpatents

MacArthur, Duncan W.; Allander, Krag S.; Bounds, John A.

1996-01-01

A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone.

Improving Factor Score Estimation Through the Use of Observed Background Characteristics

PubMed Central

Curran, Patrick J.; Cole, Veronica; Bauer, Daniel J.; Hussong, Andrea M.; Gottfredson, Nisha

2016-01-01

A challenge facing nearly all studies in the psychological sciences is how to best combine multiple items into a valid and reliable score to be used in subsequent modelling. The most ubiquitous method is to compute a mean of items, but more contemporary approaches use various forms of latent score estimation. Regardless of approach, outside of large-scale testing applications, scoring models rarely include background characteristics to improve score quality. The current paper used a Monte Carlo simulation design to study score quality for different psychometric models that did and did not include covariates across levels of sample size, number of items, and degree of measurement invariance. The inclusion of covariates improved score quality for nearly all design factors, and in no case did the covariates degrade score quality relative to not considering the influences at all. Results suggest that the inclusion of observed covariates can improve factor score estimation. PMID:28757790

Mitigation strategies against radiation-induced background for space astronomy missions

NASA Astrophysics Data System (ADS)

Davis, C. S. W.; Hall, D.; Keelan, J.; O'Farrell, J.; Leese, M.; Holland, A.

2018-01-01

The Advanced Telescope for High ENergy Astrophysics (ATHENA) mission is a major upcoming space-based X-ray observatory due to be launched in 2028 by ESA, with the purpose of mapping the early universe and observing black holes. Background radiation is expected to constitute a large fraction of the total system noise in the Wide Field Imager (WFI) instrument on ATHENA, and designing an effective system to reduce the background radiation impacting the WFI will be crucial for maximising its sensitivity. Significant background sources are expected to include high energy protons, X-ray fluorescence lines, 'knock-on' electrons and Compton electrons. Due to the variety of the different background sources, multiple shielding methods may be required to achieve maximum sensitivity in the WFI. These techniques may also be of great interest for use in future space-based X-ray experiments. Simulations have been developed to model the effect of a graded-Z shield on the X-ray fluorescence background. In addition the effect of a 90nm optical blocking filter on the secondary electron background has been investigated and shown to modify the requirements of any secondary electron shielding that is to be used.

A Projection Quality-Driven Tube Current Modulation Method in Cone-Beam CT for IGRT: Proof of Concept.

PubMed

Men, Kuo; Dai, Jianrong

2017-12-01

To develop a projection quality-driven tube current modulation method in cone-beam computed tomography for image-guided radiotherapy based on the prior attenuation information obtained by the planning computed tomography and then evaluate its effect on a reduction in the imaging dose. The QCKV-1 phantom with different thicknesses (0-400 mm) of solid water upon it was used to simulate different attenuation (μ). Projections were acquired with a series of tube current-exposure time product (mAs) settings, and a 2-dimensional contrast to noise ratio was analyzed for each projection to create a lookup table of mAs versus 2-dimensional contrast to noise ratio, μ. Before a patient underwent computed tomography, the maximum attenuation [Formula: see text] within the 95% range of each projection angle (θ) was estimated according to the planning computed tomography images. Then, a desired 2-dimensional contrast to noise ratio value was selected, and the mAs setting at θ was calculated with the lookup table of mAs versus 2-dimensional contrast to noise ratio,[Formula: see text]. Three-dimensional cone-beam computed tomography images were reconstructed using the projections acquired with the selected mAs. The imaging dose was evaluated with a polymethyl methacrylate dosimetry phantom in terms of volume computed tomography dose index. Image quality was analyzed using a Catphan 503 phantom with an oval body annulus and a pelvis phantom. For the Catphan 503 phantom, the cone-beam computed tomography image obtained by the projection quality-driven tube current modulation method had a similar quality to that of conventional cone-beam computed tomography . However, the proposed method could reduce the imaging dose by 16% to 33% to achieve an equivalent contrast to noise ratio value. For the pelvis phantom, the structural similarity index was 0.992 with a dose reduction of 39.7% for the projection quality-driven tube current modulation method. The proposed method could reduce the

Substance consumption in adolescents with and without an immigration background: a representative study-What part of an immigration background is protective against binge drinking?

PubMed

Donath, Carolin; Baier, Dirk; Graessel, Elmar; Hillemacher, Thomas

2016-11-14

Representative data indicate that adolescents with an immigration background show less harmful patterns of consumption, for example, they practice binge drinking less often. It remains to be shown whether this also applies to substances such as tobacco and cannabis and if the "healthier" patterns of consumption are permanent or if they gradually disappear as the level of integration increases. Using representative data, the current study was designed to a) present the epidemiology of the consumption of alcohol, tobacco, and cannabis of adolescents with and without an immigration background in 2013 and b) to analyze which immigration-specific variables predict problematic alcohol consumption in adolescents with an immigration background. A representative, written survey was administered to 9512 students in the 9th grade from Lower Saxony, Germany in 2013 by the "Kriminologisches Forschungsinstitut Niedersachsen (KfN)." Data were collected from 1763 adolescents with an immigration background regarding their cultural, structural, social, and identificative integration. These variables were introduced as predictors in a multiple logistic regression analysis with binge drinking during the last 30 days as the dependent variable. Compared with German adolescents without an immigration background, significantly fewer adolescents with an immigration background had already tried alcohol, but they were significantly more likely to report experience with cigarettes and cannabis. In the group of adolescents with an immigration background, the percentage of binge drinkers fluctuated by country of origin (p < .001). In the regression model, binge drinking was associated with a lower targeted school leaving certificate (p < .001), not living on social welfare (p = .038), and the strong assimilation (p = .015) of the adolescent. Binge drinking was negatively associated with attitudes that favored segregation (p < .001) and a stronger attachment of the parents

Toward real-time quantification of fluorescence molecular probes using target/background ratio for guiding biopsy and endoscopic therapy of esophageal neoplasia.

PubMed

Jiang, Yang; Gong, Yuanzheng; Rubenstein, Joel H; Wang, Thomas D; Seibel, Eric J

2017-04-01

Multimodal endoscopy using fluorescence molecular probes is a promising method of surveying the entire esophagus to detect cancer progression. Using the fluorescence ratio of a target compared to a surrounding background, a quantitative value is diagnostic for progression from Barrett's esophagus to high-grade dysplasia (HGD) and esophageal adenocarcinoma (EAC). However, current quantification of fluorescent images is done only after the endoscopic procedure. We developed a Chan-Vese-based algorithm to segment fluorescence targets, and subsequent morphological operations to generate background, thus calculating target/background (T/B) ratios, potentially to provide real-time guidance for biopsy and endoscopic therapy. With an initial processing speed of 2 fps and by calculating the T/B ratio for each frame, our method provides quasireal-time quantification of the molecular probe labeling to the endoscopist. Furthermore, an automatic computer-aided diagnosis algorithm can be applied to the recorded endoscopic video, and the overall T/B ratio is calculated for each patient. The receiver operating characteristic curve was employed to determine the threshold for classification of HGD/EAC using leave-one-out cross-validation. With 92% sensitivity and 75% specificity to classify HGD/EAC, our automatic algorithm shows promising results for a surveillance procedure to help manage esophageal cancer and other cancers inspected by endoscopy.

Method and composition for improving flux pinning and critical current in superconductors

DOEpatents

Morris, Donald E.

1995-01-01

Superconducting materials and methods of forming superconducting materials are disclosed. Highly oxidized superconductors are heated at a relatively high temperature so as to release oxygen, which migrates out of the material, and form a non-superconducting phase which does not diffuse out of grains of the material. The material is then reoxidized at a lower temperature, leaving the non-superconducting inclusions inside a superconducting phase. The non-superconducting inclusions act as pinning centers in the superconductor, increasing the critical current thereof.

Method and composition for improving flux pinning and critical current in superconductors

DOEpatents

Morris, D.E.

1995-07-04

Superconducting materials and methods of forming superconducting materials are disclosed. Highly oxidized superconductors are heated at a relatively high temperature so as to release oxygen, which migrates out of the material, and form a non-superconducting phase which does not diffuse out of grains of the material. The material is then reoxidized at a lower temperature, leaving the non-superconducting inclusions inside a superconducting phase. The non-superconducting inclusions act as pinning centers in the superconductor, increasing the critical current thereof. 14 figs.

Non-contact current and voltage sensing method using a clamshell housing and a ferrite cylinder

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

Carpenter, Gary D.; El-Essawy, Wael; Ferreira, Alexandre Peixoto

2016-04-26

A method of measurement using a detachable current and voltage sensor provides an isolated and convenient technique for to measuring current passing through a conductor such as an AC branch circuit wire, as well as providing an indication of an electrostatic potential on the wire, which can be used to indicate the phase of the voltage on the wire, and optionally a magnitude of the voltage. The device includes a housing that contains the current and voltage sensors, which may be a ferrite cylinder with a hall effect sensor disposed in a gap along the circumference to measure current, ormore » alternative a winding provided through the cylinder along its axis and a capacitive plate or wire disposed adjacent to, or within, the ferrite cylinder to provide the indication of the voltage.« less

Calculation of background effects on the VESUVIO eV neutron spectrometer

NASA Astrophysics Data System (ADS)

Mayers, J.