Pre-Launch Radiometric Performance Characterization of the Advanced Technology Microwave Sounder on the Joint Polar Satellite System-1 Satellite

NASA Technical Reports Server (NTRS)

Smith, Craig K.; Kim, Edward; Leslie, R. Vincent; Lyu, Joseph; McCormick, Lisa M.; Anderson, Kent

2017-01-01

The Advanced Technology Microwave Sounder (ATMS) is a space-based, cross-track radiometer for operational atmospheric temperature and humidity sounding, utilizing 22 channels over a frequency range from 23 to 183 gigahertz. The ATMS for the Joint Polar Satellite System-1 has undergone two rounds of re-work in 2014-2015 and 2016, following performance issues discovered during and following thermal vacuum chamber (TVAC) testing at the instrument and observatory level. Final shelf-level testing, including measurement of pass band characteristics and spectral response functions, was completed in December 2016. Final instrument-level TVAC testing and calibration occurred during February 2017. Here we will describe the instrument-level TVAC calibration process, and illustrate with results from the final TVAC calibration effort.

Concentration polarization of hyaluronan on the surface of the synovial lining of infused joints

PubMed Central

Lu, Y; Levick, JR; Wang, W

2004-01-01

Hyaluronan (HA) in joints conserves the lubricating synovial fluid by making trans-synovial fluid escape almost insensitive to pressure elevation (e.g. effusions, joint flexion). This phenomenon, ‘outflow buffering’, was discovered during HA infusion into the rabbit knee joint cavity. It was also found that HA is partially reflected by the joint lining (molecular sieving), and that the reflected fraction R decreases as trans-synovial filtration rate Q is increased. It was postulated therefore that outflow buffering is mediated by HA reflection. Reflection creates a HA concentration polarization layer, the osmotic pressure of which opposes fluid loss. A steady-state, cross-flow ultrafiltration model was previously used to explain the outflow buffering and negative R-vs.-Q relation. However, the steady-state, cross-perfusion assumptions restricted the model's applicability for an infused, dead-end cavity or a non-infused joint during cyclical motion. We therefore developed a new, non-steady-state model which describes the time course of dead-end, partial HA ultrafiltration. The model describes the progressive build-up of a HA concentration polarization layer at the synovial surface over time. Using experimental parameter values, the model successfully accounts for the observed negative R-vs.-Q relation and shows that the HA reflected fraction (R) also depends on HA diffusivity, membrane area expansion and the synovial HA reflection coefficient. The non-steady-state model thus explains existing experimental work, and it is a key stage in understanding synovial fluid turnover in intact, moving, human joints or osteoarthritic joints treated by HA injections. PMID:15579541

Joint Science Education Project: Learning about polar science in Greenland

NASA Astrophysics Data System (ADS)

Foshee Reed, Lynn

2014-05-01

The Joint Science Education Project (JSEP) is a successful summer science and culture opportunity in which students and teachers from the United States, Denmark, and Greenland come together to learn about the research conducted in Greenland and the logistics involved in supporting the research. They conduct experiments first-hand and participate in inquiry-based educational activities alongside scientists and graduate students at a variety of locations in and around Kangerlussuaq, Greenland, and on the top of the ice sheet at Summit Station. The Joint Committee, a high-level forum involving the Greenlandic, Danish and U.S. governments, established the Joint Science Education Project in 2007, as a collaborative diplomatic effort during the International Polar Year to: • Educate and inspire the next generation of polar scientists; • Build strong networks of students and teachers among the three countries; and • Provide an opportunity to practice language and communication skills Since its inception, JSEP has had 82 student and 22 teacher participants and has involved numerous scientists and field researchers. The JSEP format has evolved over the years into its current state, which consists of two field-based subprograms on site in Greenland: the Greenland-led Kangerlussuaq Science Field School and the U.S.-led Arctic Science Education Week. All travel, transportation, accommodations, and meals are provided to the participants at no cost. During the 2013 Kangerlussuaq Science Field School, students and teachers gathered data in a biodiversity study, created and set geo- and EarthCaches, calculated glacial discharge at a melt-water stream and river, examined microbes and tested for chemical differences in a variety of lakes, measured ablation at the edge of the Greenland Ice Sheet, and learned about fossils, plants, animals, minerals and rocks of Greenland. In addition, the students planned and led cultural nights, sharing food, games, stories, and traditions of

Three-dimensional polarization algebra for all polarization sensitive optical systems.

PubMed

Li, Yahong; Fu, Yuegang; Liu, Zhiying; Zhou, Jianhong; Bryanston-Cross, P J; Li, Yan; He, Wenjun

2018-05-28

Using three-dimensional (3D) coherency vector (9 × 1), we develop a new 3D polarization algebra to calculate the polarization properties of all polarization sensitive optical systems, especially when the incident optical field is partially polarized or un-polarized. The polarization properties of a high numerical aperture (NA) microscope objective (NA = 1.25 immersed in oil) are analyzed based on the proposed 3D polarization algebra. Correspondingly, the polarization simulation of this high NA optical system is performed by the commercial software VirtualLAB Fusion. By comparing the theoretical calculations with polarization simulations, a perfect matching relation is obtained, which demonstrates that this 3D polarization algebra is valid to quantify the 3D polarization properties for all polarization sensitive optical systems.

Pre-Launch Characterization of the Advanced Technology Microwave Sounder (ATMS) on the Joint Polar Satellite System-1 Satellite (JPSS-1)

NASA Astrophysics Data System (ADS)

Kim, Edward; Leslie, Vince; Lyu, Joseph; Smith, Craig; McCormick, Lisa; Anderson, Kent

2016-04-01

The Advanced Technology Microwave Sounder (ATMS) is the newest generation of microwave sounder in the international fleet of polar-orbiting weather satellites, replacing the Advanced Microwave Sounding Unit (AMSU) which first entered service in 1998. The first ATMS was launched aboard the Suomi NPP (S-NPP) satellite in late 2011. The second ATMS is manifested on the Joint Polar Satellite System-1 Satellite (JPSS-1). ATMS provides 22 channels of temperature and humidity sounding observations over a frequency range from 23 to 183 GHz. These microwave soundings provide the highest impact data ingested by operational Numerical Weather Prediction (NWP) models, and are the most critical of the polar-orbiting satellite observations, particularly because microwave sensing can penetrate clouds. This paper will present performance characterizations from pre-launch calibration measurements of the JPSS-1 ATMS just completed in December, 2015. The measurements were conducted in a thermal vacuum chamber with blackbody targets simulating cold space, ambient, and a variable Earth scene. They represent the best opportunity for calibration characterization of the instrument since the environment can be carefully controlled. We will present characterizations of the sensitivity (NEDT), accuracy, nonlinearity, noise spectral characteristics, gain stability, repeatability, and inter-channel correlation. An estimate of expected "striping" will be presented, and a discussion of reflector emissivity effects will also be provided. Comparisons will be made with the S-NPP flight unit. Finally, we will describe planned on-orbit characterizations - such as pitch and roll maneuvers - that will further improve both the measurement quality and the understanding of various error contributions.

Probabilistic joint inversion of waveforms and polarity data for double-couple focal mechanisms of local earthquakes

NASA Astrophysics Data System (ADS)

Wéber, Zoltán

2018-06-01

Estimating the mechanisms of small (M < 4) earthquakes is quite challenging. A common scenario is that neither the available polarity data alone nor the well predictable near-station seismograms alone are sufficient to obtain reliable focal mechanism solutions for weak events. To handle this situation we introduce here a new method that jointly inverts waveforms and polarity data following a probabilistic approach. The procedure called joint waveform and polarity (JOWAPO) inversion maps the posterior probability density of the model parameters and estimates the maximum likelihood double-couple mechanism, the optimal source depth and the scalar seismic moment of the investigated event. The uncertainties of the solution are described by confidence regions. We have validated the method on two earthquakes for which well-determined focal mechanisms are available. The validation tests show that including waveforms in the inversion considerably reduces the uncertainties of the usually poorly constrained polarity solutions. The JOWAPO method performs best when it applies waveforms from at least two seismic stations. If the number of the polarity data is large enough, even single-station JOWAPO inversion can produce usable solutions. When only a few polarities are available, however, single-station inversion may result in biased mechanisms. In this case some caution must be taken when interpreting the results. We have successfully applied the JOWAPO method to an earthquake in North Hungary, whose mechanism could not be estimated by long-period waveform inversion. Using 17 P-wave polarities and waveforms at two nearby stations, the JOWAPO method produced a well-constrained focal mechanism. The solution is very similar to those obtained previously for four other events that occurred in the same earthquake sequence. The analysed event has a strike-slip mechanism with a P axis oriented approximately along an NE-SW direction.

Polarity effect of electromigration on mechanical properties of lead-free solder joints

NASA Astrophysics Data System (ADS)

Ren, Fei

flip chip solder joints induced by electromigration is observed, in which the fracture position migrates from the middle to the cathode interface of the joint with increasing current density and time. The transition is explained by the polarity effect of electromigration, particular due to the accumulation of vacancies at the cathode interface.

Joint compensation scheme of polarization crosstalk, intersymbol interference, frequency offset, and phase noise based on cascaded Kalman filter

NASA Astrophysics Data System (ADS)

Zhang, Qun; Yang, Yanfu; Xiang, Qian; Zhou, Zhongqing; Yao, Yong

2018-02-01

A joint compensation scheme based on cascaded Kalman filter is proposed, which can implement polarization tracking, channel equalization, frequency offset, and phase noise compensation simultaneously. The experimental results show that the proposed algorithm can not only compensate multiple channel impairments simultaneously but also improve the polarization tracking capacity and accelerate the convergence speed. The scheme has up to eight times faster convergence speed compared with radius-directed equalizer (RDE) + Max-FFT (maximum fast Fourier transform) + BPS (blind phase search) and can track up polarization rotation 60 times and 15 times faster than that of RDE + Max-FFT + BPS and CMMA (cascaded multimodulus algorithm) + Max-FFT + BPS, respectively.

The EUMETSAT Polar System - Second Generation (EPS-SG) micro-wave imaging (MWI) mission

NASA Astrophysics Data System (ADS)

Bojkov, B. R.; Accadia, C.; Klaes, D.; Canestri, A.; Cohen, M.

2017-12-01

The EUMETSAT Polar System (EPS) will be followed by a second generation system called EPS-SG. This new family of missions will contribute to the Joint Polar System being jointly set up with NOAA in the timeframe 2020-2040. These satellites will fly, like Metop (EPS), in a sun synchronous, low earth orbit at 830 km altitude and 09:30 local time descending node, providing observations over the full globe with revisit times of 12 hours. EPS-SG consists of two different satellites configurations, the EPS-SGa series dedicated to IR and MW sounding, and the EPS-SGb series dedicated to microwave imaging and scatterometry. The EPS-SG family will consist of three successive launches of each satellite-type. The Microwave Imager (MWI) will be hosted on Metop-SGb series of satellites, with the primary objective of supporting Numerical Weather Prediction (NWP) at regional and global scales. Other applications will be observation of surface parameters such as sea ice concentration and hydrology applications. The 18 MWI instrument frequencies range from 18.7 GHz to 183 GHz. All MWI channels up to 89 GHz will measure V- and H polarizations. The MWI was also designed to provide continuity of measurements for select heritage microwave imager channels (e.g. SSM/I, AMSR-E). The additional sounding channels such as the 50-55 and 118 GHz bands will provide additional cloud and precipitation information over sea and land. This combination of channels was successfully tested on the NPOESS Aircraft Sounder Testbed - Microwave Sounder (NAST-M) airborne radiometer, and it is the first time that will be implemented in a conical scanning configuration in a single instrument. An overview of the EPS-SG programme and the MWI instrument will be presented.

Polarization rotation in meteor burst communication systems

NASA Astrophysics Data System (ADS)

Cannon, P. S.

1986-06-01

Theoretical modeling of several meteor burst communication (MBC) paths indicates that polarization rotation losses are significant for a linearly polarized system operating near 40 MHz. Losses for a hybrid system with physical installation problems, consisting of linearly polarized transmitting and circularly polarized receiving antennas, were found to be less. Both ionospheric Faraday rotation polarization changes, and underdense meteor trail scattering wave polarization rotation, are considered. These losses are found to cause a 15-70 percent data throughput reduction of the value predicted for the situation without polarization rotation, in the two 40-MHz linearly polarized links considered for noon summer solstice conditions during high solar sunspot number periods. Qualitative experimental confirmation is provided through a cross polarization approach.

Rheumatoid arthritis-affected temporomandibular joint pain analgesia by linear polarized near infrared irradiation.

PubMed

Yokoyama, K; Oku, T

1999-07-01

To describe a new short-term treatment for pain in rheumatoid arthritis (RA)-affected temporomandibular joint (TMJ). We investigated four female patients (age 42.8+/-26.0 yr) with chronic rheumatoid arthritis affecting a single TMJ. Patients had received antirheumatic drugs such as sodium aurothiomalate, and as a result showed no symptoms in other body joints. Linear polarized near infrared radiation using Super Lizer was applied weekly with and/or without jaw movement to the unilateral skin areas overlying the mandibular fossa, anterior articular tubercle, masseter muscle and posterior margin of the ramus of the mandible. The duration of irradiation to each point was two seconds on and ten seconds off per cycle and the intensity at each point was approximately 138 J x cm(-2) at a wavelength of 830 nm. Interincisal distance was measured with maximal mouth opening in the absence and presence of pain before and after each treatment. Additionally, subjective TMJ pain scores assessed using a visual analog scale were performed for painful maximal mouth opening before and after each irradiation. TMJ pain disappeared after only four treatments. Moreover, painless maximal mouth opening without pain after irradiation in three patients was on average improved to 5.3+/-2.1 mm. However, one case was observed where the opening length prior to irradiation did not improve, despite the fact that the RA-affected TMJ pain had disappeared. Application of linear polarized near infrared irradiation to patients with RA-affected TMJ pain is an effective and non-invasive short-term treatment.

Students' Challenges with Polar Functions: Covariational Reasoning and Plotting in the Polar Coordinate System

ERIC Educational Resources Information Center

Habre, Samer

2017-01-01

Covariational reasoning has been the focus of many studies but only a few looked into this reasoning in the polar coordinate system. In fact, research on student's familiarity with polar coordinates and graphing in the polar coordinate system is scarce. This paper examines the challenges that students face when plotting polar curves using the…

Streamlining On-Demand Access to Joint Polar Satellite System (JPSS) Data Products for Weather Forecasting

NASA Astrophysics Data System (ADS)

Evans, J. D.; Tislin, D.

2017-12-01

Observations from the Joint Polar Satellite System (JPSS) support National Weather Service (NWS) forecasters, whose Advanced Weather Interactive Processing System (AWIPS) Data Delivery (DD) will access JPSS data products on demand from the National Environmental Satellite, Data, and Information Service (NESDIS) Product Distribution and Access (PDA) service. Based on the Open Geospatial Consortium (OGC) Web Coverage Service, this on-demand service promises broad interoperability and frugal use of data networks by serving only the data that a user needs. But the volume, velocity, and variety of JPSS data products impose several challenges to such a service. It must be efficient to handle large volumes of complex, frequently updated data, and to fulfill many concurrent requests. It must offer flexible data handling and delivery, to work with a diverse and changing collection of data, and to tailor its outputs into products that users need, with minimal coordination between provider and user communities. It must support 24x7 operation, with no pauses in incoming data or user demand; and it must scale to rapid changes in data volume, variety, and demand as new satellites launch, more products come online, and users rely increasingly on the service. We are addressing these challenges in order to build an efficient and effective on-demand JPSS data service. For example, on-demand subsetting by many users at once may overload a server's processing capacity or its disk bandwidth - unless alleviated by spatial indexing, geolocation transforms, or pre-tiling and caching. Filtering by variable (/ band / layer) may also alleviate network loads, and provide fine-grained variable selection; to that end we are investigating how best to provide random access into the variety of spatiotemporal JPSS data products. Finally, producing tailored products (derivatives, aggregations) can boost flexibility for end users; but some tailoring operations may impose significant server loads

Properties of a certain stochastic dynamical system, channel polarization, and polar codes

NASA Astrophysics Data System (ADS)

Tanaka, Toshiyuki

2010-06-01

A new family of codes, called polar codes, has recently been proposed by Arikan. Polar codes are of theoretical importance because they are provably capacity achieving with low-complexity encoding and decoding. We first discuss basic properties of a certain stochastic dynamical system, on the basis of which properties of channel polarization and polar codes are reviewed, with emphasis on our recent results.

Dental and Temporomandibular Joint Pathology of the Polar Bear (Ursus maritimus).

PubMed

Winer, J N; Arzi, B; Leale, D M; Kass, P H; Verstraete, F J M

2016-01-01

Museum specimens (maxillae and/or mandibles) from 317 polar bears (Ursus maritimus) were examined macroscopically according to predefined criteria and 249 specimens were included in this study. The specimens were acquired between 1906 and 2011. There were 126 specimens (50.6%) from male animals, 93 (37.3%) from female animals and 30 (12.1%) from animals of unknown sex. The ages of the animals ranged from neonate to adult, with 125 adults (50.2%) and 124 young adults (49.8%) included and neonates/juveniles excluded from the study. The number of teeth available for examination was 7,638 (73.5%); 12.3% of teeth were absent artefactually, 0.8% were deemed absent due to acquired tooth loss and 13.4% were absent congenitally. With respect to tooth morphology, 20 teeth (0.26% of available teeth) in 18 specimens (7.2% of available specimens) were small vestigial structures with crowns that were flush with the level of surrounding alveolar bone. One supernumerary tooth and one tooth with enamel hypoplasia were encountered. Persistent deciduous teeth and teeth with an aberrant number of roots were not found. Relatively few teeth (3.7%) displayed attrition/abrasion, 90% of which were the maxillary and mandibular incisor teeth, in 41 polar bears (16.5%). Nearly twice as many adult specimens exhibited attrition/abrasion as those from young adults; significantly more males were affected than females. Dental fractures were noted in 52 polar bears, affecting 20.9% of specimens and 1.3% of the total number of teeth present. More adult polar bears had dental fractures than young adults. There were 21 specimens (8.4%) that displayed overt periapical disease, affecting a total of 24 dental alveoli (0.23%). Some degree of periodontitis was seen in 199 specimens (79.9%); however, only 12.6% of dental alveoli had bony changes indicative of periodontitis. Lesions consistent with temporomandibular joint osteoarthritis (TMJ-OA) were found in 23 specimens (9.2%). TMJ-OA was significantly

Students' challenges with polar functions: covariational reasoning and plotting in the polar coordinate system

NASA Astrophysics Data System (ADS)

Habre, Samer

2017-01-01

Covariational reasoning has been the focus of many studies but only a few looked into this reasoning in the polar coordinate system. In fact, research on student's familiarity with polar coordinates and graphing in the polar coordinate system is scarce. This paper examines the challenges that students face when plotting polar curves using the corresponding plot in the Cartesian plane. In particular, it examines how students coordinate the covariation in the polar coordinate system with the covariation in the Cartesian one. The research, which was conducted in a sophomore level Calculus class at an American university operating in Lebanon, investigates in addition the challenges when students synchronize the reasoning between the two coordinate systems. For this, the mental actions that students engage in when performing covariational tasks are examined. Results show that coordinating the value of one polar variable with changes in the other was well achieved. Coordinating the direction of change of one variable with changes in the other variable was more challenging for students especially when the radial distance r is negative.

Joint carrier phase and frequency-offset estimation with parallel implementation for dual-polarization coherent receiver.

PubMed

Lu, Jianing; Li, Xiang; Fu, Songnian; Luo, Ming; Xiang, Meng; Zhou, Huibin; Tang, Ming; Liu, Deming

2017-03-06

We present dual-polarization complex-weighted, decision-aided, maximum-likelihood algorithm with superscalar parallelization (SSP-DP-CW-DA-ML) for joint carrier phase and frequency-offset estimation (FOE) in coherent optical receivers. By pre-compensation of the phase offset between signals in dual polarizations, the performance can be substantially improved. Meanwhile, with the help of modified SSP-based parallel implementation, the acquisition time of FO and the required number of training symbols are reduced by transferring the complex weights of the filters between adjacent buffers, where differential coding/decoding is not required. Simulation results show that the laser linewidth tolerance of our proposed algorithm is comparable to traditional blind phase search (BPS), while a complete FOE range of ± symbol rate/2 can be achieved. Finally, performance of our proposed algorithm is experimentally verified under the scenario of back-to-back (B2B) transmission using 10 Gbaud DP-16/32-QAM formats.

Polarization-Analyzing CMOS Image Sensor With Monolithically Embedded Polarizer for Microchemistry Systems.

PubMed

Tokuda, T; Yamada, H; Sasagawa, K; Ohta, J

2009-10-01

This paper proposes and demonstrates a polarization-analyzing CMOS sensor based on image sensor architecture. The sensor was designed targeting applications for chiral analysis in a microchemistry system. The sensor features a monolithically embedded polarizer. Embedded polarizers with different angles were implemented to realize a real-time absolute measurement of the incident polarization angle. Although the pixel-level performance was confirmed to be limited, estimation schemes based on the variation of the polarizer angle provided a promising performance for real-time polarization measurements. An estimation scheme using 180 pixels in a 1deg step provided an estimation accuracy of 0.04deg. Polarimetric measurements of chiral solutions were also successfully performed to demonstrate the applicability of the sensor to optical chiral analysis.

Evaluation of pipe-type cable joint restraint systems

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

Silver, D.A.; Seman, G.W.

1990-03-01

the purpose of this project was to evaluate two systems for restraining the movement of 345kV high-pressure oil-filled (HPOF) cable joints during load cycling. Problems with joints and adjacent cables due to thermomechanical bending (TMB) experienced by the Consolidated Edison Company of New York and Public Service Electric Gas Company of New Jersey are reviewed. Some approaches to reducing or preventing TMB induced damage to HPOF pipe type cable joints are discussed. The design and operation of a special test apparatus for simulating TMB effects under laboratory conditions is described. One of the two joint restraint systems evaluated under thismore » project was developed by PSE G and employed wedging devices, which could be retrofitted into existing installations, that limited the longitudinal movement of the joints during load cycling. The other system developed by Pirelli Cable Corporation applied the restraining force to the cylindrical portion of the hand applied joint insulation by means of support spiders and steel rods attached to the reducer faces. The test results show that the PSE G restraint system can effectively limit joint longitudinal movement while causing a minimal amount of mechanical disturbance to the joint stress cones. The test results obtained with the PCC system are inconclusive and indicate that further refinement and testing are required to demonstrate the effectiveness of this promising joint restraint system.« less

The EUMETSAT Polar System-Second Generation (EPS-SG) micro-wave and sub-millimetre wave imaging missions

NASA Astrophysics Data System (ADS)

Accadia, Christophe; Schlüssel, Peter; Phillips, Pepe L.; Wilson, J. Julian W.

2013-10-01

The EUMETSAT Polar System (EPS) will be followed by a second generation system, EPS-SG, in the 2020-2040 timeframe and contribute to the Joint Polar System being jointly set up with NOAA. Among the various missions which are part of EPS-SG, there are the Microwave Imager (MWI) and the Ice Cloud Imager (ICI). The MWI frequencies are from 18 GHz up to 183 GHz. All MWI channels up to 89 GHz measure both V and H polarisations. The primary objective of the MWI mission is to support Numerical Weather Prediction at regional and global scales. The MWI will not only provide continuity of measurements for some heritage microwave imager channels (e.g. SSM/I, AMSR-E) but will also include additional channels such as the 50-55 / 118 GHz bands. The combined use of these channels will provide more information on cloud and precipitation over sea and land. The ICI will provide measurements over the sub-millimetre spectral range contributing to an innovative characterisation of clouds over the whole globe. The ICI has channels at 183 GHz, 325 GHz and 448 GHz with single V polarisation and two channels at 243 GHz and 664 GHz with both V and H polarisation. The ICI's primary objectives are to support climate monitoring and validation of ice cloud models and the parameterisation of ice clouds in weather and climate models through the provision of ice cloud products.

A polarization system for persistent chemical detection

NASA Astrophysics Data System (ADS)

Craven-Jones, Julia; Appelhans, Leah; Couphos, Eric; Embree, Todd; Finnegan, Patrick; Goldstein, Dennis; Karelitz, David; LaCasse, Charles; Luk, Ting S.; Mahamat, Adoum; Massey, Lee; Tanbakuchi, Anthony; Washburn, Cody; Vigil, Steven

2015-09-01

We report on the development of a prototype polarization tag based system for detecting chemical vapors. The system primarily consists of two components, a chemically sensitive tag that experiences a change in its optical polarization properties when exposed to a specific chemical of interest, and an optical imaging polarimeter that is used to measure the polarization properties of the tags. Although the system concept could be extended to other chemicals, for the initial system prototype presented here the tags were developed to be sensitive to hydrogen fluoride (HF) vapors. HF is used in many industrial processes but is highly toxic and thus monitoring for its presence and concentration is often of interest for personnel and environmental safety. The tags are periodic multilayer structures that are produced using standard photolithographic processes. The polarimetric imager has been designed to measure the degree of linear polarization reflected from the tags in the short wave infrared. By monitoring the change in the reflected polarization signature from the tags, the polarimeter can be used to determine if the tag was exposed to HF gas. In this paper, a review of the system development effort and preliminary test results are presented and discussed, as well as our plan for future work.

Joint Online Thesis and Research System (JOTARS)

DTIC Science & Technology

2006-09-01

NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited JOINT ONLINE ...September 2006 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE: Joint Online Thesis and Research System (JOTARS) 6. AUTHOR...prototype website is the Joint Online Thesis and Research System (JOTARS). The specific functional objectives of JOTARS are to establish standard

[Research on Spectral Polarization Imaging System Based on Static Modulation].

PubMed

Zhao, Hai-bo; Li, Huan; Lin, Xu-ling; Wang, Zheng

2015-04-01

The main disadvantages of traditional spectral polarization imaging system are: complex structure, with moving parts, low throughput. A novel method of spectral polarization imaging system is discussed, which is based on static polarization intensity modulation combined with Savart polariscope interference imaging. The imaging system can obtain real-time information of spectral and four Stokes polarization messages. Compared with the conventional methods, the advantages of the imaging system are compactness, low mass and no moving parts, no electrical control, no slit and big throughput. The system structure and the basic theory are introduced. The experimental system is established in the laboratory. The experimental system consists of reimaging optics, polarization intensity module, interference imaging module, and CCD data collecting and processing module. The spectral range is visible and near-infrared (480-950 nm). The white board and the plane toy are imaged by using the experimental system. The ability of obtaining spectral polarization imaging information is verified. The calibration system of static polarization modulation is set up. The statistical error of polarization degree detection is less than 5%. The validity and feasibility of the basic principle is proved by the experimental result. The spectral polarization data captured by the system can be applied to object identification, object classification and remote sensing detection.

National Polar-orbiting Operational Environmental Satellite System (NPOESS) Design and Architecture

NASA Astrophysics Data System (ADS)

Hinnant, F.

2008-12-01

The National Oceanic and Atmospheric Administration (NOAA), Department of Defense (DoD), and National Aeronautics and Space Administration (NASA) are jointly acquiring the next-generation weather and environmental satellite system - the National Polar-orbiting Operational Environmental Satellite System (NPOESS). NPOESS will replace the current Polar-orbiting Operational Environmental Satellites (POES) managed by NOAA and the Defense Meteorological Satellite Program (DMSP) managed by the DoD and will provide continuity for the NASA Earth Observing System (EOS) with the launch of the NPOESS Preparatory Project (NPP). This poster will provide an overview of the NPOESS architecture, which includes four segments. The space segment includes satellites in two orbits that carry a suite of sensors to collect meteorological, oceanographic, climatological, and solar-geophysical observations of the Earth, atmosphere, and near-Earth space environment. The NPOESS design allows centralized mission management and delivers high quality environmental products to military, civil and scientific users through a Command, Control, and Communication Segment (C3S). The data processing for NPOESS is accomplished through an Interface Data Processing Segment (IDPS)/Field Terminal Segment (FTS) that processes NPOESS satellite data to provide environmental data products to NOAA and DoD processing centers operated by the United States government as well as to remote terminal users. The Launch Support Segment completes the four segments that make up NPOESS that will enhance the connectivity between research and operations and provide critical operational and scientific environmental measurements to military, civil, and scientific users until 2026.

Effect of linear polarized near-infrared light irradiation on flexibility of shoulder and ankle joints.

PubMed

Demura, S; Yamaji, S; Ikemoto, Y

2002-12-01

There is a possibility that heat stimulus by linear polarized near-infrared light irradiation (PL: Super Lizer HA-30, Tokyo Medical Laboratory) improves the range of joint motion, because the flexibility of soft-part tissues, such as a muscle or a tendon, is improved by increasing the muscle temperature. The purpose of this study was to examine the influence of PL-irradiation on the ranges of shoulder and ankle motions. 30 healthy young adults (15 males: mean+/-SD, age 19.1+/-0.8 yrs, height 173.3+/-4.6 cm, body mass 68.5+/-8.0 kg and 15 females: mean+/-SD, age 19.2+/-0.7 yrs, height 162.3+/-4.5 cm, body mass 58.1+/-6.6 kg) participated in the experiment under PL-irradiation and no-irradiation (placebo) conditions. the angles of shoulder and ankle joint motions were measured twice, before and after the PL- and placebo-irradiations. The angle of a motion was defined as the angle connecting 3 points at linearity as follows: for the shoulder, the greater trochanter, acromion, and caput ulnare, and for the ankle, the knee joint, fassa of lateral malleolus and metacarpal bone. Each angle was measured when a subject extended or flexed maximally without support. The trial-to-trial reliability of each range of joint motion was very high. All parameters in PL-irradiation were significantly larger in postirradiation than pre-irradiation, and the value of postirradiation in PL-irradiation was significantly greater than that for placebo. The ranges of shoulder and ankle motions in placebo-irradiation were also significantly greater in postirradiation than pre-irradiation. Moreover, the change rate for each range of joint motion between pre- and postirradiations was significantly greater in PL-irradiation in both joints. In PL-irradiation, most subject's motions were greater in postirradiation than pre-irradiation, but not in the placebo-irradiation. The effect of PL-irradiation tended to be greater on subjects with a small range of a joint motion. It is considered from the

UAH mathematical model of the variable polarity plasma ARC welding system calculation

NASA Technical Reports Server (NTRS)

Hung, R. J.

1994-01-01

Significant advantages of Variable Polarity Plasma Arc (VPPA) welding process include faster welding, fewer repairs, less joint preparation, reduced weldment distortion, and absence of porosity. A mathematical model is presented to analyze the VPPA welding process. Results of the mathematical model were compared with the experimental observation accomplished by the GDI team.

Fiber-based polarization-sensitive OCT of the human retina with correction of system polarization distortions

PubMed Central

Braaf, Boy; Vermeer, Koenraad A.; de Groot, Mattijs; Vienola, Kari V.; de Boer, Johannes F.

2014-01-01

In polarization-sensitive optical coherence tomography (PS-OCT) the use of single-mode fibers causes unpredictable polarization distortions which can result in increased noise levels and erroneous changes in calculated polarization parameters. In the current paper this problem is addressed by a new Jones matrix analysis method that measures and corrects system polarization distortions as a function of wavenumber by spectral analysis of the sample surface polarization state and deeper located birefringent tissue structures. This method was implemented on a passive-component depth-multiplexed swept-source PS-OCT system at 1040 nm which was theoretically modeled using Jones matrix calculus. High-resolution B-scan images are presented of the double-pass phase retardation, diattenuation, and relative optic axis orientation to show the benefits of the new analysis method for in vivo imaging of the human retina. The correction of system polarization distortions yielded reduced phase retardation noise, and better estimates of the diattenuation and the relative optic axis orientation in weakly birefringent tissues. The clinical potential of the system is shown by en face visualization of the phase retardation and optic axis orientation of the retinal nerve fiber layer in a healthy volunteer and a glaucoma patient with nerve fiber loss. PMID:25136498

Determination of characteristics of degenerative joint disease using optical coherence tomography and polarization sensitive optical coherence tomography.

PubMed

Xie, Tuqiang; Guo, Shuguang; Zhang, Jun; Chen, Zhongping; Peavy, George M

2006-10-01

Previous studies have demonstrated that optical coherence tomography (OCT) could be used to delineate alterations in the microstructure of cartilage, and have suggested that changes in the polarization state of light as detected by OCT could provide information on the birefringence properties of articular cartilage as influenced by disease. In this study we have used both OCT and polarization sensitive optical coherence tomography (PS-OCT) technologies to evaluate normal and abnormal bovine articular cartilage according to established structural, organizational, and birefringent characteristics of degenerative joint disease (DJD) in order to determine if this technology can be used to differentiate various stages of DJD as a minimally invasive imaging tool. Fresh bovine femoral-tibial joints were obtained from an abattoir, and 45 cartilage specimens were harvested from 8 tibial plateaus. Whole ex vivo specimens of normal and degenerative articular cartilage were imaged by both OCT and PS-OCT, then fixed and processed for histological evaluation. OCT/PS-OCT images and corresponding histology sections of each specimen were scored according to a modified Mankin structural grading scale and compared. OCT and PS-OCT imaging allowed structural evaluation of intact articular cartilage along a 6 mm surface length to a depth of 2 mm with a transverse resolution of 12 microm and an axial resolution of 10 microm. The OCT and PS-OCT images demonstrated characteristic alterations in the structure of articular cartilage with a high correlation to histological evaluation (kappa = 0.776). The OCT images were able to demonstrate early to advanced structural changes of articular cartilage while the optical phase retardation images obtained by PS-OCT imaging were able to discriminate areas where disorganization of the cartilage matrix was present, however, these characteristics are much different than those reported where OCT images alone were used to characterize tissue

Minimally invasive arthrodesis for chronic sacroiliac joint dysfunction using the SImmetry SI Joint Fusion system.

PubMed

Miller, Larry E; Block, Jon E

2014-01-01

Chronic sacroiliac (SI) joint-related low back pain (LBP) is a common, yet under-diagnosed and undertreated condition due to difficulties in accurate diagnosis and highly variable treatment practices. In patients with debilitating SI-related LBP for at least 6 months duration who have failed conservative management, arthrodesis is a viable option. The SImmetry(®) SI Joint Fusion System is a novel therapy for SI joint fusion, not just fixation, which utilizes a minimally invasive surgical approach, instrumented fixation for immediate stability, and joint preparation with bone grafting for a secure construct in the long term. The purpose of this report is to describe the minimally invasive SI Joint Fusion System, including patient selection criteria, implant characteristics, surgical technique, postoperative recovery, and biomechanical testing results. Advantages and limitations of this system will be discussed.

Minimally invasive arthrodesis for chronic sacroiliac joint dysfunction using the SImmetry SI Joint Fusion system

PubMed Central

Miller, Larry E; Block, Jon E

2014-01-01

Chronic sacroiliac (SI) joint-related low back pain (LBP) is a common, yet under-diagnosed and undertreated condition due to difficulties in accurate diagnosis and highly variable treatment practices. In patients with debilitating SI-related LBP for at least 6 months duration who have failed conservative management, arthrodesis is a viable option. The SImmetry® SI Joint Fusion System is a novel therapy for SI joint fusion, not just fixation, which utilizes a minimally invasive surgical approach, instrumented fixation for immediate stability, and joint preparation with bone grafting for a secure construct in the long term. The purpose of this report is to describe the minimally invasive SI Joint Fusion System, including patient selection criteria, implant characteristics, surgical technique, postoperative recovery, and biomechanical testing results. Advantages and limitations of this system will be discussed. PMID:24851059

Performance of wireless optical communication systems under polarization effects over atmospheric turbulence

NASA Astrophysics Data System (ADS)

Zhang, Jiankun; Li, Ziyang; Dang, Anhong

2018-06-01

It has been recntly shown that polarization state of propagation beam would suffer from polarization fluctuations due to the detrimental effects of atmospheric turbulence. This paper studies the performance of wireless optical communication (WOC) systems in the presence of polarization effect of atmosphere. We categorize the atmospheric polarization effect into polarization rotation, polarization-dependent power loss, and phase shift effect, with each effect described and modeled with the help of polarization-coherence theory and the extended Huygens-Fresnelprinciple. The channel matrices are derived to measure the cross-polarization interference of the system. Signal-to-noise ratio and bit error rate for polarization multiplexing system and polarization modulation system are obtained to assess the viability using the approach of M turbulence model. Monte Carlo simulation results show the performance of polarization based WOC systems to be degraded by atmospheric polarization effect, which could be evaluated precisely using the proposed model with given turbulent strengths.

Thermal Protection System with Staggered Joints

NASA Technical Reports Server (NTRS)

Simon, Xavier D. (Inventor); Robinson, Michael J. (Inventor); Andrews, Thomas L. (Inventor)

2014-01-01

The thermal protection system disclosed herein is suitable for use with a spacecraft such as a reentry module or vehicle, where the spacecraft has a convex surface to be protected. An embodiment of the thermal protection system includes a plurality of heat resistant panels, each having an outer surface configured for exposure to atmosphere, an inner surface opposite the outer surface and configured for attachment to the convex surface of the spacecraft, and a joint edge defined between the outer surface and the inner surface. The joint edges of adjacent ones of the heat resistant panels are configured to mate with each other to form staggered joints that run between the peak of the convex surface and the base section of the convex surface.

QM-8 field joint protection system, volume 7

NASA Technical Reports Server (NTRS)

Hale, Elgie

1989-01-01

The pre-launch functioning data of the Field Joint Protection System (JPS) used on QM-8 are presented. Also included is the post fire condition of the JPS components following the test firing of the motor. The JPS components are: field joint heaters; field joint sensors; field joint moisture seal; moisture seal kevlar retaining straps; field joint external extruded cork insulation; vent valve; power cables; and igniter heater.

A dual polarized antenna system using a meanderline polarizer

NASA Technical Reports Server (NTRS)

Burger, H. A.

1978-01-01

Certain applications of synthetic aperture radars require transmitting on one linear polarization and receiving on two orthogonal linear polarizations for adequate characterization of the surface. To meet the current need at minimum cost, it was desirable to use two identical horizontally polarized shaped beam antennas and to change the polarization of one of them by a polarization conversion plate. The plate was realized as a four-layer meanderline polarizer designed to convert horizontal polarization to vertical.

Modeling joint restoration strategies for interdependent infrastructure systems

PubMed Central

Simonovic, Slobodan P.

2018-01-01

Life in the modern world depends on multiple critical services provided by infrastructure systems which are interdependent at multiple levels. To effectively respond to infrastructure failures, this paper proposes a model for developing optimal joint restoration strategy for interdependent infrastructure systems following a disruptive event. First, models for (i) describing structure of interdependent infrastructure system and (ii) their interaction process, are presented. Both models are considering the failure types, infrastructure operating rules and interdependencies among systems. Second, an optimization model for determining an optimal joint restoration strategy at infrastructure component level by minimizing the economic loss from the infrastructure failures, is proposed. The utility of the model is illustrated using a case study of electric-water systems. Results show that a small number of failed infrastructure components can trigger high level failures in interdependent systems; the optimal joint restoration strategy varies with failure occurrence time. The proposed models can help decision makers to understand the mechanisms of infrastructure interactions and search for optimal joint restoration strategy, which can significantly enhance safety of infrastructure systems. PMID:29649300

Modeling joint restoration strategies for interdependent infrastructure systems.

PubMed

Zhang, Chao; Kong, Jingjing; Simonovic, Slobodan P

2018-01-01

Life in the modern world depends on multiple critical services provided by infrastructure systems which are interdependent at multiple levels. To effectively respond to infrastructure failures, this paper proposes a model for developing optimal joint restoration strategy for interdependent infrastructure systems following a disruptive event. First, models for (i) describing structure of interdependent infrastructure system and (ii) their interaction process, are presented. Both models are considering the failure types, infrastructure operating rules and interdependencies among systems. Second, an optimization model for determining an optimal joint restoration strategy at infrastructure component level by minimizing the economic loss from the infrastructure failures, is proposed. The utility of the model is illustrated using a case study of electric-water systems. Results show that a small number of failed infrastructure components can trigger high level failures in interdependent systems; the optimal joint restoration strategy varies with failure occurrence time. The proposed models can help decision makers to understand the mechanisms of infrastructure interactions and search for optimal joint restoration strategy, which can significantly enhance safety of infrastructure systems.

A Novel Attitude Determination System Aided by Polarization Sensor

PubMed Central

Zhi, Wei; Chu, Jinkui; Li, Jinshan; Wang, Yinlong

2018-01-01

This paper aims to develop a novel attitude determination system aided by polarization sensor. An improved heading angle function is derived using the perpendicular relationship between directions of E-vector of linearly polarized light and solar vector in the atmospheric polarization distribution model. The Extended Kalman filter (EKF) with quaternion differential equation as a dynamic model is applied to fuse the data from sensors. The covariance functions of filter process and measurement noises are deduced in detail. The indoor and outdoor tests are conducted to verify the validity and feasibility of proposed attitude determination system. The test results showed that polarization sensor is not affected by magnetic field, thus the proposed system can work properly in environments containing the magnetic interference. The results also showed that proposed system has higher measurement accuracy than common attitude determination system and can provide precise parameters for Unmanned Aerial Vehicle (UAV) flight control. The main contribution of this paper is implementation of the EKF for incorporating the self-developed polarization sensor into the conventional attitude determination system. The real-world experiment with the quad-rotor proved that proposed system can work in a magnetic interference environment and provide sufficient accuracy in attitude determination for autonomous navigation of vehicle. PMID:29315256

Mechanical end joint system for structural column elements

NASA Technical Reports Server (NTRS)

Bush, H. G.; Wallsom, R. E. (Inventor)

1982-01-01

A mechanical end joint system, useful for the transverse connection of strut elements to a common node, comprises a node joint half with a semicircular tongue and groove, and a strut joint half with a semicircular tongue and groove. The two joint halves are engaged transversely and the connection is made secure by the inherent physical property characteristics of locking latches and/or by a spring-actioned shaft. A quick release mechanism provides rapid disengagement of the joint halves.

Evaluation of longitudinal joint tie bar system.

DOT National Transportation Integrated Search

2011-09-01

"An adequate longitudinal joint tie bar system is essential in the overall performance of concrete pavement. Excessive : longitudinal joint openings are believed to be caused by either inadequate tie bar size or spacing or improper tie bar : installa...

Elevated sacroilac joint uptake ratios in systemic lupus erythematosus

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

De Smet, A.A.; Mahmood, T.; Robinson, R.G.

1984-08-01

Sacroiliac joint radiographs and radionuclide sacroiliac joint uptake ratios were obtained on 14 patients with active systemic lupus erythematosus. Elevated joint ratios were found unilaterally in two patients and bilaterally in seven patients when their lupus was active. In patients whose disease became quiescent, the uptake ratios returned to normal. Two patients had persistently elevated ratios with continued clinical and laboratory evidence of active lupus. Mild sacroiliac joint sclerosis and erosions were detected on pelvic radiographs in these same two patients. Elevated quantitative sacroiliac joint uptake ratios may occur as a manifestation of active systemic lupus erythematosus.

Design of polarization imaging system based on CIS and FPGA

NASA Astrophysics Data System (ADS)

Zeng, Yan-an; Liu, Li-gang; Yang, Kun-tao; Chang, Da-ding

2008-02-01

As polarization is an important characteristic of light, polarization image detecting is a new image detecting technology of combining polarimetric and image processing technology. Contrasting traditional image detecting in ray radiation, polarization image detecting could acquire a lot of very important information which traditional image detecting couldn't. Polarization image detecting will be widely used in civilian field and military field. As polarization image detecting could resolve some problem which couldn't be resolved by traditional image detecting, it has been researched widely around the world. The paper introduces polarization image detecting in physical theory at first, then especially introduces image collecting and polarization image process based on CIS (CMOS image sensor) and FPGA. There are two parts including hardware and software for polarization imaging system. The part of hardware include drive module of CMOS image sensor, VGA display module, SRAM access module and the real-time image data collecting system based on FPGA. The circuit diagram and PCB was designed. Stokes vector and polarization angle computing method are analyzed in the part of software. The float multiply of Stokes vector is optimized into just shift and addition operation. The result of the experiment shows that real time image collecting system could collect and display image data from CMOS image sensor in real-time.

Wavelet analysis of polarization maps of polycrystalline biological fluids networks

NASA Astrophysics Data System (ADS)

Ushenko, Y. A.

2011-12-01

The optical model of human joints synovial fluid is proposed. The statistic (statistic moments), correlation (autocorrelation function) and self-similar (Log-Log dependencies of power spectrum) structure of polarization two-dimensional distributions (polarization maps) of synovial fluid has been analyzed. It has been shown that differentiation of polarization maps of joint synovial fluid with different physiological state samples is expected of scale-discriminative analysis. To mark out of small-scale domain structure of synovial fluid polarization maps, the wavelet analysis has been used. The set of parameters, which characterize statistic, correlation and self-similar structure of wavelet coefficients' distributions of different scales of polarization domains for diagnostics and differentiation of polycrystalline network transformation connected with the pathological processes, has been determined.

Dynamic analysis of clamp band joint system subjected to axial vibration

NASA Astrophysics Data System (ADS)

Qin, Z. Y.; Yan, S. Z.; Chu, F. L.

2010-10-01

Clamp band joints are commonly used for connecting circular components together in industry. Some of the systems jointed by clamp band are subjected to dynamic load. However, very little research on the dynamic characteristics for this kind of joint can be found in the literature. In this paper, a dynamic model for clamp band joint system is developed. Contact and frictional slip between the components are accommodated in this model. Nonlinear finite element analysis is conducted to identify the model parameters. Then static experiments are carried out on a scaled model of the clamp band joint to validate the joint model. Finally, the model is adopted to study the dynamic characteristics of the clamp band joint system subjected to axial harmonic excitation and the effects of the wedge angle of the clamp band joint and the preload on the response. The model proposed in this paper can represent the nonlinearity of the clamp band joint and be used conveniently to investigate the effects of the structural and loading parameters on the dynamic characteristics of this type of joint system.

Polar Textures

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site] Context image for PIA03638 Polar Textures

This image illustrates the variety of textures that appear in the south polar region during late summer.

Image information: VIS instrument. Latitude 80.5S, Longitude 57.9E. 17 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Atmospheric aerosol measurements by employing a polarization scheimpflug lidar system

NASA Astrophysics Data System (ADS)

Mei, Liang; Guan, Peng; Yang, Yang

2018-04-01

A polarization Scheimpflug lidar system based on the Scheimpflug principle has been developed by employing a compact 808-nm multimode highpower laser diode and two highly integrated CMOS sensors in Dalian University of Technology (DLUT), Dalian, China. The parallel and orthogonal polarized backscattering signal are recorded by two 45 degree tilted image sensors, respectively. Atmospheric particle measurements were carried out by employing the polarization Scheimpflug lidar system.

Integrated High-Speed Torque Control System for a Robotic Joint

NASA Technical Reports Server (NTRS)

Davis, Donald R. (Inventor); Radford, Nicolaus A. (Inventor); Permenter, Frank Noble (Inventor); Valvo, Michael C. (Inventor); Askew, R. Scott (Inventor)

2013-01-01

A control system for achieving high-speed torque for a joint of a robot includes a printed circuit board assembly (PCBA) having a collocated joint processor and high-speed communication bus. The PCBA may also include a power inverter module (PIM) and local sensor conditioning electronics (SCE) for processing sensor data from one or more motor position sensors. Torque control of a motor of the joint is provided via the PCBA as a high-speed torque loop. Each joint processor may be embedded within or collocated with the robotic joint being controlled. Collocation of the joint processor, PIM, and high-speed bus may increase noise immunity of the control system, and the localized processing of sensor data from the joint motor at the joint level may minimize bus cabling to and from each control node. The joint processor may include a field programmable gate array (FPGA).

Observation of non-classical correlations in sequential measurements of photon polarization

NASA Astrophysics Data System (ADS)

Suzuki, Yutaro; Iinuma, Masataka; Hofmann, Holger F.

2016-10-01

A sequential measurement of two non-commuting quantum observables results in a joint probability distribution for all output combinations that can be explained in terms of an initial joint quasi-probability of the non-commuting observables, modified by the resolution errors and back-action of the initial measurement. Here, we show that the error statistics of a sequential measurement of photon polarization performed at different measurement strengths can be described consistently by an imaginary correlation between the statistics of resolution and back-action. The experimental setup was designed to realize variable strength measurements with well-controlled imaginary correlation between the statistical errors caused by the initial measurement of diagonal polarizations, followed by a precise measurement of the horizontal/vertical polarization. We perform the experimental characterization of an elliptically polarized input state and show that the same complex joint probability distribution is obtained at any measurement strength.

Noninvasive biosignal detection radar system using circular polarization.

PubMed

Lee, Jee-Hoon; Hwang, Jung Man; Choi, Dong Hyuk; Park, Seong-Ook

2009-05-01

This paper proposes an integrated hypersensitive Doppler radar system through a circular polarization characteristic. Through the idea of a reverse sense of rotation when the reflecting surface is perfectly conducting, it is shown that the detecting property of the system can be effectively improved by using antennas that have a reverse polarization. This bistatic radar system can be used in noninvasively sensing biosignals such as respiration and heart rates with the periodic movement of skin and muscle near the heart. The operating frequency of the system is in the X-band and the radar size is 95 x50 x13 mm(3).

Polarization variations in installed fibers and their influence on quantum key distribution systems.

PubMed

Ding, Yu-Yang; Chen, Hua; Wang, Shuang; He, De-Yong; Yin, Zhen-Qiang; Chen, Wei; Zhou, Zheng; Guo, Guang-Can; Han, Zheng-Fu

2017-10-30

Polarization variations in the installed fibers are complex and volatile, and would severely affect the performances of polarization-sensitive quantum key distribution (QKD) systems. Based on the recorded data about polarization variations of different installed fibers, we establish an analytical methodology to quantitatively evaluate the influence of polarization variations on polarization-sensitive QKD systems. Using the increased quantum bit error rate induced by polarization variations as a key criteria, we propose two parameters - polarization drift time and required tracking speed - to characterize polarization variations. For field buried and aerial fibers with different length, we quantitatively evaluate the influence of polarization variations, and also provide requirements and suggestions for polarization basis alignment modules of QKD systems deployed in different kind of fibers.

Data Management Considerations for the International Polar Year

NASA Astrophysics Data System (ADS)

Parsons, M. A.; Weaver, R. L.; Duerr, R.; Barry, R. G.

2004-12-01

The legacy of the International Geophysical Year and past International Polar Years is in the scientific data collected. The upcoming IPY will result in an unprecedented collection of geophysical and social science data from the polar regions. To realize the full scientific and interdisciplinary utility of these data it is essential to consider the design of data management systems early in the expirimental planning process. This paper will present an array of high level data management considerations for the IPY including cross-disciplinary data access, essential documentation, system guidance, and long-term data archiving. Specific recommendations from relevant international organizations such as the Joint Committee on Antarctic Data Management and the WCRP Climate and Cryosphere Programme will be considered. The potential role of the Electronic Geophysical Year and other International Years will also be discussed.

Polarized radiance distribution measurements of skylight. I. System description and characterization.

PubMed

Voss, K J; Liu, Y

1997-08-20

A new system to measure the natural skylight polarized radiance distribution has been developed. The system is based on a fish-eye lens, CCD camera system, and filter changer. With this system sequences of images can be combined to determine the linear polarization components of the incident light field. Calibration steps to determine the system 's polarization characteristics are described. Comparisons of the radiance measurements of this system and a simple pointing radiometer were made in the field and agreed within 10 % for measurements at 560 and 670 nm and 25 % at 860 nm. Polarization tests were done in the laboratory. The accuracy of the intensity measurements is estimated to be 10 %, while the accuracy of measurements of elements of the Mueller matrix are estimated to be 2 %.

Drill/borescope System for the Mars Polar Pathfinder

NASA Technical Reports Server (NTRS)

Paige, D. A.; Wood, S. E.; Vasavada, A. R.

1993-01-01

The primary goals of the Mars Polar Pathfinder (MPP) Discovery Mission are to characterize the composition and structure of Mars' north polar ice cap, and to determine whether a climate record may be preserved in layers of ice and dust. The MPP would land as close as possible to the geographic north pole of Mars and use a set of instruments similar to those used by glaciologists to study polar ice caps on Earth: a radar sounder, a drill/borescope system, and a thermal probe. The drill/borescope system will drill approximately 50 cm into the surface and image the sides of the hole at 10 micron resolution for compositional and stratigraphic analysis. Several uncertainties have guided the development of this instrument, and they are discussed.

Polarity management: the key challenge for integrated health systems.

PubMed

Burns, L R

1999-01-01

Integrated health systems are confronted with numerous dilemmas that must be managed. Many of these dilemmas are an inherent part of the system's structure, given that multiple competing hospitals, medical groups, and (sometimes) health plans are often under one organizational roof. This article presents an analysis of these dilemmas--referred to in the management literature as polarities--as they are found in six integrated health systems in Illinois. The nine polarities that must be managed include (1) hospital systems that want to be organizations of physicians; (2) system expansion by growing the physician component; (3) system centralization and physician decentralization; (4) centripetal and centrifugal forces involving physicians; (5) system objectives and physician interests; (6) system centralization and hospital decentralization; (7) primary care physicians and specialists; (8) physician autonomy via collectivization; and (9) vertical and virtual integration. The article identifies some of the solutions to the polarities that have been enacted by systems. In general, executives and physicians in integrated health systems must attend to the processes of integration as much as or more than the structures of integration.

Cross-Polarization Optical Coherence Tomography with Active Maintenance of the Circular Polarization of a Sounding Wave in a Common Path System

NASA Astrophysics Data System (ADS)

Gelikonov, V. M.; Romashov, V. N.; Shabanov, D. V.; Ksenofontov, S. Yu.; Terpelov, D. A.; Shilyagin, P. A.; Gelikonov, G. V.; Vitkin, I. A.

2018-05-01

We consider a cross-polarization optical coherence tomography system with a common path for the sounding and reference waves and active maintenance of the circular polarization of a sounding wave. The system is based on the formation of birefringent characteristics of the total optical path, which are equivalent to a quarter-wave plate with a 45° orientation of its optical axes with respect to the linearly polarized reference wave. Conditions under which any light-polarization state can be obtained using a two-element phase controller are obtained. The dependence of the local cross-scattering coefficient of light in a model medium and biological tissue on the sounding-wave polarization state is demonstrated. The necessity of active maintenance of the circular polarization of a sounding wave in this common path system (including a flexible probe) is shown to realize uniform optimal conditions for cross-polarization studies of biological tissue.

Designation of a polarization-converting system and its enhancement of double-frequency efficiency

NASA Astrophysics Data System (ADS)

Wang, Peng; Li, Xiao; Shang, YaPing; Xu, XiaoJun

2015-08-01

A polarization-converting system is designed by using axicons and wave plate transforming naturally polarized laser to linearly polarized laser at real time to resolve difficulties of generating high-power linearly polarized laser. The energy conversion efficiency reaches 96.9% with an enhancement of extinction ratio from 29.7% to 98%. The system also keeps excellent far field divergence. In the one-way SHG experiment the double frequency efficiency reached 4.32% using the generated linearly polarized laser, much higher than that of the naturally polarized laser but lower than that of the linearly polarized laser from PBS. And the phenomenon of the SHG experiment satisfies the principle of phase matching. The experiment proves that this polarization-converting system will not affect laser structure which controls easily and needs no feedback and controlling system with stable and reliable properties at the same time. It can absolutely be applied to the polarization-conversion of high power laser and enhance the SHG efficiency and the energy efficiency.

Research on the system scheme and experiment for the active laser polarization imaging

NASA Astrophysics Data System (ADS)

Fu, Qiang; Duan, Jin; Zhao, Rui; Li, Zheng; Zhang, Su; Zhan, Juntong; Zhu, Yong; Jiang, Hui-Lin

2015-10-01

The polarization imaging detection technology increased the polarization information on the basis of the intensity imaging, which is extensive application in the military and civil and other fields. The research present and development trend of polarization imaging detection technology was introduce, the system scheme of the active polarization imaging detection was put forward, and the key technologies such as the polarization information detection, optical system design, polarization radiation calibration and image fusion approach was analyzed. On this basis, detection system by existing equipment of laboratory was set up, and on the different materials such as wood, metal, plastic and goal was detected by polarization imaging to realize the active polarization imaging detection. The results show that image contrast of the metal and man-made objects is higher, the polarization effect is better, which provided the basis on the better performance of the polarization imaging instruments.

Mechanical end joint system for connecting structural column elements

NASA Technical Reports Server (NTRS)

Bush, Harold G. (Inventor); Mikulas, Martin M., Jr. (Inventor); Wallsom, Richard E. (Inventor)

1990-01-01

A mechanical end joint system is presented that eliminates the possibility of free movements between the joint halves during loading or vibration. Both node joint body (NJB) and column end joint body (CEJB) have cylindrical engaging ends. Each of these ends has an integral semicircular tongue and groove. The two joint halves are engaged transversely - the tongue of the NJB mating with the groove of the CEJB and vice versa. The joint system employs a spring loaded internal latch mechanism housed in the CEJB. During mating, this mechanism is pushed away from the NJB and enters the NJB when mating is completed. In order to lock the joint and add a preload across the tongue and groove faces, an operating ring collar is rotated through 45 deg causing an internal mechanism to compress a Belleville washer preload mechanism. This causes an equal and opposite force to be exerted on the latch bolt and the latch plunger. This force presses the two joint halves tightly together. In order to prevent inadvertent disassembly, a secondary lock is also engaged when the joint is closed. Plungers are carried in the operating ring collar. When the joint is closed, the plungers fall into tracks on the CEJB, which allows the joint to be opened only when the operating ring collar and plungers are pushed directly away from the joining end. One application of this invention is the rapid assembly and disassembly of diverse skeletal framework structures which is extremely important in many projects involving the exploration of space.

Polarized object detection in crabs: a two-channel system.

PubMed

Basnak, Melanie Ailín; Pérez-Schuster, Verónica; Hermitte, Gabriela; Berón de Astrada, Martín

2018-05-25

Many animal species take advantage of polarization vision for vital tasks such as orientation, communication and contrast enhancement. Previous studies have suggested that decapod crustaceans use a two-channel polarization system for contrast enhancement. Here, we characterize the polarization contrast sensitivity in a grapsid crab . We estimated the polarization contrast sensitivity of the animals by quantifying both their escape response and changes in heart rate when presented with polarized motion stimuli. The motion stimulus consisted of an expanding disk with an 82 deg polarization difference between the object and the background. More than 90% of animals responded by freezing or trying to avoid the polarized stimulus. In addition, we co-rotated the electric vector (e-vector) orientation of the light from the object and background by increments of 30 deg and found that the animals' escape response varied periodically with a 90 deg period. Maximum escape responses were obtained for object and background e-vectors near the vertical and horizontal orientations. Changes in cardiac response showed parallel results but also a minimum response when e-vectors of object and background were shifted by 45 deg with respect to the maxima. These results are consistent with an orthogonal receptor arrangement for the detection of polarized light, in which two channels are aligned with the vertical and horizontal orientations. It has been hypothesized that animals with object-based polarization vision rely on a two-channel detection system analogous to that of color processing in dichromats. Our results, obtained by systematically varying the e-vectors of object and background, provide strong empirical support for this theoretical model of polarized object detection. © 2018. Published by The Company of Biologists Ltd.

Low loss fusion splicing polarization-maintaining photonic crystal fiber and conventional polarization-maintaining fiber

NASA Astrophysics Data System (ADS)

Zuoming, Sun; Ningfang, Song; Jing, Jin; Jingming, Song; Pan, Ma

2012-12-01

An efficient and simple method of fusion splicing of a Polarization-Maintaining Photonic Crystal Fiber (PM-PCF) and a conventional Polarization-Maintaining Fiber (PMF) with a low loss of 0.65 dB in experiment is reported. The minimum bending diameter of the joint can reach 2 cm. Theoretical calculation of the splicing loss based on mode field diameters (MFDs) mismatch of the two kinds of fibers is given. All parameters affected the splicing loss were studied.

Spin polarization of two-dimensional electron system in parabolic potential

NASA Astrophysics Data System (ADS)

Miyake, Takashi; Totsuji, Chieko; Nakanishi, Kenta; Tsuruta, Kenji; Totsuji, Hiroo

2008-09-01

We analyze the ground state of the two-dimensional quantum system of electrons confined in a parabolic potential with the system size around 100 at 0 K. We map the system onto a classical system on the basis of the classical-map hypernetted-chain (CHNC) method which has been proven to work in the integral-equation-based analyses of uniform systems and apply classical Monte Carlo and molecular dynamics simulations. We find that, when we decrease the strength of confinement keeping the number of confined electrons fixed, the energy of the spin-polarized state with somewhat lower average density becomes smaller than that of the spin-unpolarized state with somewhat higher average density. This system thus undergoes the transition from the spin-unpolarized state to the spin polarized state and the corresponding critical value of r estimated from the average density is as low as r∼0.4 which is much smaller than the r value for the Wigner lattice formation. When we compare the energies of spin-unpolarized and spin-polarized states for given average density, our data give the critical r value for the transition between unpolarized and polarized states around 10 which is close to but still smaller than the known possibility of polarization at r∼27. The advantage of our method is a direct applicability to geometrically complex systems which are difficult to analyze by integral equations and this is an example.

VIIRS-J1 Polarization Narrative

NASA Technical Reports Server (NTRS)

Waluschka, Eugene; McCorkel, Joel; McIntire, Jeff; Moyer, David; McAndrew, Brendan; Brown, Steven W.; Lykke, Keith; Butler, James; Meister, Gerhard; Thome, Kurtis J.

2015-01-01

The VIS/NIR bands polarization sensitivity of Joint Polar Satellite Sensor 1 (JPSS1) Visible/Infrared Imaging Radiometer Suite (VIIRS) instrument was measured using a broadband source. While polarization sensitivity for bands M5-M7, I1, and I2 was less than 2.5%, the maximum polarization sensitivity for bands M1, M2, M3, and M4 was measured to be 6.4%, 4.4%, 3.1%, and 4.3%, respectively with a polarization characterization uncertainty of less than 0.3%. A detailed polarization model indicated that the large polarization sensitivity observed in the M1 to M4 bands was mainly due to the large polarization sensitivity introduced at the leading and trailing edges of the newly manufactured VISNIR bandpass focal plane filters installed in front of the VISNIR detectors. This was confirmed by polarization measurements of bands M1 and M4 bands using monochromatic light. Discussed are the activities leading up to and including the instruments two polarization tests, some discussion of the polarization model and the model results, the role of the focal plane filters, the polarization testing of the Aft-Optics-Assembly, the testing of the polarizers at Goddard and NIST and the use of NIST's T-SIRCUS for polarization testing and associated analyses and results.

State preparation and detector effects in quantum measurements of rotation with circular polarization-entangled photons and photon counting

NASA Astrophysics Data System (ADS)

Cen, Longzhu; Zhang, Zijing; Zhang, Jiandong; Li, Shuo; Sun, Yifei; Yan, Linyu; Zhao, Yuan; Wang, Feng

2017-11-01

Circular polarization-entangled photons can be used to obtain an enhancement of the precision in a rotation measurement. In this paper, the method of entanglement transformation is used to produce NOON states in circular polarization from a readily generated linear polarization-entangled photon source. Detection of N -fold coincidences serves as the postselection and N -fold superoscillating fringes are obtained simultaneously. A parity strategy and conditional probabilistic statistics contribute to a better fringe, saturating the angle sensitivity to the Heisenberg limit. The impact of imperfect state preparation and detection is discussed both separately and jointly. For the separated case, the influence of each system imperfection is pronounced. For the joint case, the feasibility region for surpassing the standard quantum limit is given. Our work pushes the state preparation of circular polarization-entangled photons to the same level as that in the case of linear polarization. It is also confirmed that entanglement can be transformed into different frames for specific applications, serving as a useful scheme for using entangled sources.

North Polar Cap

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site]

This week we will be looking at five examples of laminar wind flow on the north polar cap. On Earth, gravity-driven south polar cap winds are termed 'catabatic' winds. Catabatic winds begin over the smooth expanse of the cap interior due to temperature differences between the atmosphere and the surface. Once begun, the winds sweep outward along the surface of the polar cap toward the sea. As the polar surface slopes down toward sealevel, the wind speeds increase. Catabatic wind speeds in the Antartic can reach several hundreds of miles per hour.

In the images of the Martian north polar cap we can see these same type of winds. Notice the streamers of dust moving downslope over the darker trough sides, these streamers show the laminar flow regime coming off the cap. Within the trough we see turbulent clouds of dust, kicked up at the trough base as the winds slow down and enter a chaotic flow regime.

The horizontal lines in these images are due to framelet overlap and lighting conditions over the bright polar cap.

Image information: VIS instrument. Latitude 86.5, Longitude 64.5 East (295.5 West). 40 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation

North Polar Cap

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site]

This week we will be looking at five examples of laminar wind flow on the north polar cap. On Earth, gravity-driven south polar cap winds are termed 'catabatic' winds. Catabatic winds begin over the smooth expanse of the cap interior due to temperature differences between the atmosphere and the surface. Once begun, the winds sweep outward along the surface of the polar cap toward the sea. As the polar surface slopes down toward sealevel, the wind speeds increase. Catabatic wind speeds in the Antartic can reach several hundreds of miles per hour.

In the images of the Martian north polar cap we can see these same type of winds. Notice the streamers of dust moving downslope over the darker trough sides, these streamers show the laminar flow regime coming off the cap. Within the trough we see turbulent clouds of dust, kicked up at the trough base as the winds slow down and enter a chaotic flow regime.

The horizontal lines in these images are due to framelet overlap and lighting conditions over the bright polar cap.

Image information:VIS instrument. Latitude 86.5, longitude 57.4 East (302.6 West). 40 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is

North Polar Cap

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site]

This week we will be looking at five examples of laminar wind flow on the north polar cap. On Earth, gravity-driven south polar cap winds are termed 'catabatic' winds. Catabatic winds begin over the smooth expanse of the cap interior due to temperature differences between the atmosphere and the surface. Once begun, the winds sweep outward along the surface of the polar cap toward the sea. As the polar surface slopes down toward sealevel, the wind speeds increase. Catabatic wind speeds in the Antartic can reach several hundreds of miles per hour.

In the images of the Martian north polar cap we can see these same type of winds. Notice the streamers of dust moving downslope over the darker trough sides, these streamers show the laminar flow regime coming off the cap. Within the trough we see turbulent clouds of dust, kicked up at the trough base as the winds slow down and enter a chaotic flow regime.

The horizontal lines in these images are due to framelet overlap and lighting conditions over the bright polar cap.

Image information: VIS instrument. Latitude 84.3, Longitude 314.4 East (45.6 West). 40 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation

North Polar Cap

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site]

This week we will be looking at five examples of laminar wind flow on the north polar cap. On Earth, gravity-driven south polar cap winds are termed 'catabatic' winds. Catabatic winds begin over the smooth expanse of the cap interior due to temperature differences between the atmosphere and the surface. Once begun, the winds sweep outward along the surface of the polar cap toward the sea. As the polar surface slopes down toward sealevel, the wind speeds increase. Catabatic wind speeds in the Antartic can reach several hundreds of miles per hour.

In the images of the Martian north polar cap we can see these same type of winds. Notice the streamers of dust moving downslope over the darker trough sides, these streamers show the laminar flow regime coming off the cap. Within the trough we see turbulent clouds of dust, kicked up at the trough base as the winds slow down and enter a chaotic flow regime.

The horizontal lines in these images are due to framelet overlap and lighting conditions over the bright polar cap.

Image information: VIS instrument. Latitude 84.2, Longitude 57.4 East (302.6 West). 40 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation

Study of the Polarization Strategy for Electron Cyclotron Heating Systems on HL-2M

NASA Astrophysics Data System (ADS)

Zhang, F.; Huang, M.; Xia, D. H.; Song, S. D.; Wang, J. Q.; Huang, B.; Wang, H.

2016-06-01

As important components integrated in transmission lines of electron cyclotron heating systems, polarizers are mainly used to obtain the desired polarization for highly efficient coupling between electron cyclotron waves and plasma. The polarization strategy for 105-GHz electron cyclotron heating systems of HL-2M tokamak is studied in this paper. Considering the polarizers need high efficiency, stability, and low loss to realize any polarization states, two sinusoidal-grooved polarizers, which include a linear polarizer and an elliptical polarizer, are designed with the coordinate transformation method. The parameters, the period p and the depth d, of two sinusoidal-grooved polarizers are optimized by a phase difference analysis method to achieve an almost arbitrary polarization. Finally, the optimized polarizers are manufactured and their polarization characteristics are tested with a low-power test platform. The experimental results agree well with the numerical calculations, indicating that the designed polarizers can meet the polarization requirements of the electron cyclotron heating systems of HL-2M tokamak.

Global positioning method based on polarized light compass system

NASA Astrophysics Data System (ADS)

Liu, Jun; Yang, Jiangtao; Wang, Yubo; Tang, Jun; Shen, Chong

2018-05-01

This paper presents a global positioning method based on a polarized light compass system. A main limitation of polarization positioning is the environment such as weak and locally destroyed polarization environments, and the solution to the positioning problem is given in this paper which is polarization image de-noising and segmentation. Therefore, the pulse coupled neural network is employed for enhancing positioning performance. The prominent advantages of the present positioning technique are as follows: (i) compared to the existing position method based on polarized light, better sun tracking accuracy can be achieved and (ii) the robustness and accuracy of positioning under weak and locally destroyed polarization environments, such as cloudy or building shielding, are improved significantly. Finally, some field experiments are given to demonstrate the effectiveness and applicability of the proposed global positioning technique. The experiments have shown that our proposed method outperforms the conventional polarization positioning method, the real time longitude and latitude with accuracy up to 0.0461° and 0.0911°, respectively.

46 CFR 154.506 - Mechanical expansion joint: Limits in a piping system.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Mechanical expansion joint: Limits in a piping system..., Construction and Equipment Cargo and Process Piping Systems § 154.506 Mechanical expansion joint: Limits in a piping system. Mechanical expansion joints in a piping system outside of a cargo tank: (a) May be...

46 CFR 154.506 - Mechanical expansion joint: Limits in a piping system.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Mechanical expansion joint: Limits in a piping system..., Construction and Equipment Cargo and Process Piping Systems § 154.506 Mechanical expansion joint: Limits in a piping system. Mechanical expansion joints in a piping system outside of a cargo tank: (a) May be...

46 CFR 154.506 - Mechanical expansion joint: Limits in a piping system.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Mechanical expansion joint: Limits in a piping system..., Construction and Equipment Cargo and Process Piping Systems § 154.506 Mechanical expansion joint: Limits in a piping system. Mechanical expansion joints in a piping system outside of a cargo tank: (a) May be...

46 CFR 154.506 - Mechanical expansion joint: Limits in a piping system.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Mechanical expansion joint: Limits in a piping system..., Construction and Equipment Cargo and Process Piping Systems § 154.506 Mechanical expansion joint: Limits in a piping system. Mechanical expansion joints in a piping system outside of a cargo tank: (a) May be...

46 CFR 154.506 - Mechanical expansion joint: Limits in a piping system.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Mechanical expansion joint: Limits in a piping system..., Construction and Equipment Cargo and Process Piping Systems § 154.506 Mechanical expansion joint: Limits in a piping system. Mechanical expansion joints in a piping system outside of a cargo tank: (a) May be...

Airborne and Maritime/Fixed Station Joint Tactical Radio System (AMF JTRS)

DTIC Science & Technology

2015-12-01

Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-421 Airborne & Maritime/Fixed Station Joint Tactical Radio System (AMF JTRS) As of FY 2017...Information Program Name Airborne & Maritime/Fixed Station Joint Tactical Radio System (AMF JTRS) DoD Component Army Responsible Office References SAR...UNCLASSIFIED 5 Mission and Description Airborne & Maritime/Fixed Station Joint Tactical Radio System (AMF JTRS) products are software programmable

NCTR using a polarization-agile coherent radar system

NASA Astrophysics Data System (ADS)

Walton, E. K.; Moffatt, D. L.; Garber, F. D.; Kamis, A.; Lai, C. Y.

1986-01-01

This report describes the results of the first year of a research project performed by the Ohio State University ElectroScience Laboratory (OSU/ESL) for the Naval Weapons Center (NWC). The goal of this project is to explore the use of the polarization properties of the signal scattered from a radar target for the purpose of radar target identification. Various radar target identification algorithms were applied to the case of a full polarization coherent radar system, and were tested using a specific data base and noise model. The data base used to test the performance of the radar target identification algorithms developed here is a unique set of measurements made on scale models of aircraft. Measurements were made using the OSU/ESL Compact Radar Measurement Range. The range was operated in a broad-band (1-12 GHZ) mode and the full polarization matrix was measured. Calibrated values (amplitude and phase) of the RCS for the three polarization states were thus available. The polarization states are listed below.

High performance and cost effective CO-OFDM system aided by polar code.

PubMed

Liu, Ling; Xiao, Shilin; Fang, Jiafei; Zhang, Lu; Zhang, Yunhao; Bi, Meihua; Hu, Weisheng

2017-02-06

A novel polar coded coherent optical orthogonal frequency division multiplexing (CO-OFDM) system is proposed and demonstrated through experiment for the first time. The principle of a polar coded CO-OFDM signal is illustrated theoretically and the suitable polar decoding method is discussed. Results show that the polar coded CO-OFDM signal achieves a net coding gain (NCG) of more than 10 dB at bit error rate (BER) of 10^-3 over 25-Gb/s 480-km transmission in comparison with conventional CO-OFDM. Also, compared to the 25-Gb/s low-density parity-check (LDPC) coded CO-OFDM 160-km system, the polar code provides a NCG of 0.88 dB @BER = 10^-3. Moreover, the polar code can relieve the laser linewidth requirement massively to get a more cost-effective CO-OFDM system.

Ultrasonic scanning system for in-place inspection of brazed tube joints

NASA Technical Reports Server (NTRS)

Haynes, J. L.; Wages, C. G.; Haralson, H. S. (Inventor)

1973-01-01

A miniaturized ultrasonic scanning system for nondestructive in-place, non-immersion testing of brazed joints in stainless-steel tubing is described. The system is capable of scanning brazed tube joints, with limited clearance access, in 1/4 through 5/8 inch union, tee, elbow and cross configurations. The system has the capability to detect defective conditions now associated with material density changes in addition to those which are depended upon density variations. The system includes a miniaturized scanning head assembly that fits around a tube joint and rotates the transducer around and down the joint in a continuous spiral motion. The C-scan recorder is similar in principle to conventional models except that it was specially designed to track the continuous spiral scan of the tube joint. The scanner and recorder can be operated with most commercially available ultrasonic flaw detectors.

Joint design of QC-LDPC codes for coded cooperation system with joint iterative decoding

NASA Astrophysics Data System (ADS)

Zhang, Shunwai; Yang, Fengfan; Tang, Lei; Ejaz, Saqib; Luo, Lin; Maharaj, B. T.

2016-03-01

In this paper, we investigate joint design of quasi-cyclic low-density-parity-check (QC-LDPC) codes for coded cooperation system with joint iterative decoding in the destination. First, QC-LDPC codes based on the base matrix and exponent matrix are introduced, and then we describe two types of girth-4 cycles in QC-LDPC codes employed by the source and relay. In the equivalent parity-check matrix corresponding to the jointly designed QC-LDPC codes employed by the source and relay, all girth-4 cycles including both type I and type II are cancelled. Theoretical analysis and numerical simulations show that the jointly designed QC-LDPC coded cooperation well combines cooperation gain and channel coding gain, and outperforms the coded non-cooperation under the same conditions. Furthermore, the bit error rate performance of the coded cooperation employing jointly designed QC-LDPC codes is better than those of random LDPC codes and separately designed QC-LDPC codes over AWGN channels.

On Mass Polarization Effect in Three-Body Nuclear Systems

NASA Astrophysics Data System (ADS)

Filikhin, I.; Kezerashvili, R. Ya.; Suslov, V. M.; Vlahovic, B.

2018-05-01

The mass polarization effect is considered for different three-body nuclear AAB systems having a strongly bound AB and unbound AA subsystems. We employ the Faddeev equations for calculations and the Schrödinger equation for analysis of the contribution of the mass polarization term of the kinetic-energy operator. For a three-boson system the mass polarization effect is determined by the difference of the doubled binding energy of the AB subsystem 2E2 and the three-body binding energy E3(V_{AA}=0) when the interaction between the identical particles is omitted. In this case: | E3(V_{AA}=0)| >2| E2| . In the case of a system complicated by isospins(spins), such as the kaonic clusters K-K-p and ppK-, a similar evaluation is impossible. For these systems it is found that | E3(V_{AA}=0)| <2| E2| . A model with an AB potential averaged over spin(isospin) variables transforms the latter case to the first one. The mass polarization effect calculated within this model is essential for the kaonic clusters. In addition we have obtained the relation |E_3|≤|2E_2| for the binding energy of the kaonic clusters.

Disseminated Museum Displays and Participation of Students from Underrepresented Populations in Polar Research: Education and Outreach for Joint Projects in GPS and Seismology Solid Earth Science Community

NASA Astrophysics Data System (ADS)

Eriksson, S. C.; Wilson, T. J.; Anandakrishnan, S.; Aster, R. C.; Johns, B.; Anderson, K.; Taber, J.

2006-12-01

Two Antarctic projects developed by solid earth scientists in the GPS and seismology communities have rich education and outreach activities focused on disseminating information gleaned from this research and on including students from underrepresented groups. Members of the UNAVCO and IRIS research consortia along with international partners from Australia, Canada, Chile, Germany, Italy, New Zealand and the U.K. aim to deploy an ambitious GPS/seismic network to observe the Antarctic glaciological and geologic system using a multidisciplinary and internationally coordinated approach. The second project supports this network. UNAVCO and IRIS are designing and building a reliable power and communication system for autonomous polar station operation which use the latest power and communication technologies for ease of deployment and reliable multi-year operation in severe polar environments. This project will disseminate research results through an IPY/POLENET web-based museum style display based on the next-generation "Museum Lite" capability primarily supported by IRIS. "Museum Lite" uses a standard PC, touch-screen monitor, and standard Internet browsers to exploit the scalability and access of the Internet and to provide customizable content in an interactive setting. The unit is suitable for research departments, public schools, and an assortment of public venues, and can provide wide access to real-time geophysical data, ongoing research, and general information. The POLENET group will work with members of the two consortia to provide content about the project and polar science in general. One unit is to be installed at Barrow's Ilisagvit College through the Barrow Arctic Science Consortium, one at McMurdo Station in Antarctica, and two at other sites to be determined (likely in New Zealand/Australia and in the U.S.). In January, 2006, Museum Lite exhibit was installed at the Amundsen-Scott South Pole Station. Evaluation of this prototype is underway. These

Active polarization imaging system based on optical heterodyne balanced receiver

NASA Astrophysics Data System (ADS)

Xu, Qian; Sun, Jianfeng; Lu, Zhiyong; Zhou, Yu; Luan, Zhu; Hou, Peipei; Liu, liren

2017-08-01

Active polarization imaging technology has recently become the hot research field all over the world, which has great potential application value in the military and civil area. By introducing active light source, the Mueller matrix of the target can be calculated according to the incident light and the emitted or reflected light. Compared with conventional direct detection technology, optical heterodyne detection technology have higher receiving sensitivities, which can obtain the whole amplitude, frequency and phase information of the signal light. In this paper, an active polarization imaging system will be designed. Based on optical heterodyne balanced receiver, the system can acquire the horizontal and vertical polarization of reflected optical field simultaneously, which contain the polarization characteristic of the target. Besides, signal to noise ratio and imaging distance can be greatly improved.

Hierarchical spin-orbital polarization of a giant Rashba system

PubMed Central

Bawden, Lewis; Riley, Jonathan M.; Kim, Choong H.; Sankar, Raman; Monkman, Eric J.; Shai, Daniel E.; Wei, Haofei I.; Lochocki, Edward B.; Wells, Justin W.; Meevasana, Worawat; Kim, Timur K.; Hoesch, Moritz; Ohtsubo, Yoshiyuki; Le Fèvre, Patrick; Fennie, Craig J.; Shen, Kyle M.; Chou, Fangcheng; King, Phil D. C.

2015-01-01

The Rashba effect is one of the most striking manifestations of spin-orbit coupling in solids and provides a cornerstone for the burgeoning field of semiconductor spintronics. It is typically assumed to manifest as a momentum-dependent splitting of a single initially spin-degenerate band into two branches with opposite spin polarization. Combining polarization-dependent and resonant angle-resolved photoemission measurements with density functional theory calculations, we show that the two “spin-split” branches of the model giant Rashba system BiTeI additionally develop disparate orbital textures, each of which is coupled to a distinct spin configuration. This necessitates a reinterpretation of spin splitting in Rashba-like systems and opens new possibilities for controlling spin polarization through the orbital sector. PMID:26601268

Hierarchical spin-orbital polarization of a giant Rashba system.

PubMed

Bawden, Lewis; Riley, Jonathan M; Kim, Choong H; Sankar, Raman; Monkman, Eric J; Shai, Daniel E; Wei, Haofei I; Lochocki, Edward B; Wells, Justin W; Meevasana, Worawat; Kim, Timur K; Hoesch, Moritz; Ohtsubo, Yoshiyuki; Le Fèvre, Patrick; Fennie, Craig J; Shen, Kyle M; Chou, Fangcheng; King, Phil D C

2015-09-01

The Rashba effect is one of the most striking manifestations of spin-orbit coupling in solids and provides a cornerstone for the burgeoning field of semiconductor spintronics. It is typically assumed to manifest as a momentum-dependent splitting of a single initially spin-degenerate band into two branches with opposite spin polarization. Combining polarization-dependent and resonant angle-resolved photoemission measurements with density functional theory calculations, we show that the two "spin-split" branches of the model giant Rashba system BiTeI additionally develop disparate orbital textures, each of which is coupled to a distinct spin configuration. This necessitates a reinterpretation of spin splitting in Rashba-like systems and opens new possibilities for controlling spin polarization through the orbital sector.

Colorado River Sewer System Joint Venture to Upgrade Wastewater System

EPA Pesticide Factsheets

SAN FRANCISCO -Today, the Colorado River Sewer System Joint Venture, located in Parker, Ariz. entered into an agreement with the EPA to upgrade their wastewater treatment system to meet stringent water quality standards. The cost of the upgrade is ap

Virtual Passive Controller for Robot Systems Using Joint Torque Sensors

NASA Technical Reports Server (NTRS)

Aldridge, Hal A.; Juang, Jer-Nan

1997-01-01

This paper presents a control method based on virtual passive dynamic control that will stabilize a robot manipulator using joint torque sensors and a simple joint model. The method does not require joint position or velocity feedback for stabilization. The proposed control method is stable in the sense of Lyaponov. The control method was implemented on several joints of a laboratory robot. The controller showed good stability robustness to system parameter error and to the exclusion of nonlinear dynamic effects on the joints. The controller enhanced position tracking performance and, in the absence of position control, dissipated joint energy.

Automated Variable-Polarity Plasma-Arc Welding

NASA Technical Reports Server (NTRS)

Numes, A. C., Jr.; Bayless, E. O., Jr.; Jones, S. C., III; Munafo, P.; Munafo, A.; Biddle, A.; Wilson, W.

1984-01-01

Variable-polarity plasma-arc methods produces better welds at lower cost than gas-shielded tungsten-arc welding in assemblies. Weld porosity very low and costs of joint preparation, depeaking, inspection, and weld repair minimized.

Polar Layers

NASA Technical Reports Server (NTRS)

2006-01-01

[figure removed for brevity, see original site] Context image for PIA02153 Polar Layers

This image of the south polar region shows layered material. It is not known if the layers are formed yearly or if they form over the period of 10s to 100s of years or more.

Image information: VIS instrument. Latitude -80.3N, Longitude 296.2E. 17 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Analysis of Tyman green detection system based on polarization interference

NASA Astrophysics Data System (ADS)

Huang, Yaolin; Wang, Min; Shao, Xiaoping; Kou, Yuanfeng

2018-02-01

The optical surface deviation of the lens can directly affect the quality of the optical system.In order to effectively and accurately detect the surface shape, an optical surface on-line detection system based on polarization interference technology is designed and developed. The system is based on Tyman-Green interference optical path, join the polarization interference measuring technology. Based on the theoretical derivation of the optical path and the ZEMAX software simulation, the experimental optical path is constructed. The parallel light is used to detect the concave lens. The parallel light is used as the light source, the size of the polarization splitting prism, detection radius of curvature, the relations between and among the size of the lens aperture, a detection range is given.

FE analysis of SMA-based bio-inspired bone-joint system

NASA Astrophysics Data System (ADS)

Yang, S.; Seelecke, S.

2009-10-01

This paper presents the finite element (FE) analysis of a bio-inspired bone-joint system. Motivated by the BATMAV project, which aims at the development of a micro-air-vehicle platform that implements bat-like flapping flight capabilities, we study the actuation of a typical elbow joint, using shape memory alloy (SMA) in a dual manner. Micro-scale martensitic SMA wires are used as 'metal muscles' to actuate a system of humerus, elbow joint and radius, in concert with austenitic wires, which operate as flexible joints due to their superelastic character. For the FE analysis, the humerus and radius are modeled as standard elastic beams, while the elbow joint and muscle wires use the Achenbach-Muller-Seelecke SMA model as beams and cable elements, respectively. The particular focus of the paper is on the implementation of the above SMA model in COMSOL.

Experimental demonstration of polarization encoding quantum key distribution system based on intrinsically stable polarization-modulated units.

PubMed

Wang, Jindong; Qin, Xiaojuan; Jiang, Yinzhu; Wang, Xiaojing; Chen, Liwei; Zhao, Feng; Wei, Zhengjun; Zhang, Zhiming

2016-04-18

A proof-of-principle demonstration of a one-way polarization encoding quantum key distribution (QKD) system is demonstrated. This approach can automatically compensate for birefringence and phase drift. This is achieved by constructing intrinsically stable polarization-modulated units (PMUs) to perform the encoding and decoding, which can be used with four-state protocol, six-state protocol, and the measurement-device-independent (MDI) scheme. A polarization extinction ratio of about 30 dB was maintained for several hours over a 50 km optical fiber without any adjustments to our setup, which evidences its potential for use in practical applications.

Monochromatic Measurements of the JPSS-1 VIIRS Polarization Sensitivity

NASA Technical Reports Server (NTRS)

McIntire, Jeff; Moyer, David; Brown, Steven W.; Lykke, Keith R.; Waluschka, Eugene; Oudrari, Hassan; Xiong, Xiaoxiong

2016-01-01

Polarization sensitivity is a critical property that must be characterized for spaceborne remote sensing instruments designed to measure reflected solar radiation. Broadband testing of the first Joint Polar-orbiting Satellite System (JPSS-1) Visible Infrared Imaging Radiometer Suite (VIIRS) showed unexpectedly large polarization sensitivities for the bluest bands on VIIRS (centered between 400 and 600 nm). Subsequent ray trace modeling indicated that large diattenuation on the edges of the bandpass for these spectral bands was the driver behind these large sensitivities. Additional testing using the National Institute of Standards and Technologies Traveling Spectral Irradiance and Radiance Responsivity Calibrations Using Uniform Sources was added to the test program to verify and enhance the model. The testing was limited in scope to two spectral bands at two scan angles; nonetheless, this additional testing provided valuable insight into the polarization sensitivity. Analysis has shown that the derived diattenuation agreed with the broadband measurements to within an absolute difference of about0.4 and that the ray trace model reproduced the general features of the measured data. Additionally, by deriving the spectral responsivity, the linear diattenuation is shown to be explicitly dependent on the changes in bandwidth with polarization state.

Insect remote sensing using a polarization sensitive cw lidar system in chinese rice fields

NASA Astrophysics Data System (ADS)

Zhu, Shiming; Malmqvist, Elin; Li, Yiyun; Jansson, Samuel; Li, Wansha; Duan, Zheng; Fu, Wei; Svanberg, Katarina; Bood, Joakim; Feng, Hongqiang; Åkesson, Susanne; Song, Ziwei; Zhang, Baoxin; Zhao, Guangyu; Li, Dunsong; Brydegaard, Mikkel; Svanberg, Sune

2018-04-01

A joint Chinese-Swedish field campaign of Scheimpflug continuous-wave lidar monitoring of rice-field flying pest insects was pursued in very hot July weather conditions close to Guangzhou, China. The occurrence of insects, birds and bats with almost 200 hours of round-the-clock polarization-sensitive recordings was studied. Wing-beat frequency recordings and depolarization properties were used for target classification. Influence of weather conditions on the flying fauna was also investigated.

Field joint environmental protection system vibration/pressurization qualification

NASA Technical Reports Server (NTRS)

Cook, M.

1989-01-01

The procedures used and results obtained from vibration testing the redesigned solid rocket motor (RSRM) field joint environmental protection system (FJEPS), hereafter referred to as the joint protection system (JPS) are documented. The major purposes were to certify that the flight-designed JPS will withstand the dynamic environmental conditions of the redesigned solid rocket booster, and to certify that the cartridge check valve (vent valve) will relieve pressure build-up under the JPS during the initial 120 sec of flight. Also, an evaluation of the extruded cork insulation bonding was performed after the vibration testing.

Analysis methods for polarization state and energy transmission of rays propagating in optical systems

NASA Astrophysics Data System (ADS)

Liu, Chao; Liu, Qiangsheng; Cen, Zhaofeng; Li, Xiaotong

2010-11-01

Polarization state of only completely polarized light can be analyzed by some software, ZEMAX for example. Based on principles of geometrical optics, novel descriptions of the light with different polarization state are provided in this paper. Differential calculus is well used for saving the polarization state and amplitudes of sampling rays when ray tracing. The polarization state changes are analyzed in terms of several typical circumstances, such as Brewster incidence, total reflection. Natural light and partially polarized light are discussed as an important aspect. Further more, a computing method including composition and decomposition of sampling rays at each surface is also set up to analyze the energy transmission of the rays for optical systems. Adopting these analysis methods mentioned, not only the polarization state changes of the incident rays can be obtained, but also the energy distributions can be calculated. Since the energy distributions are obtained, the surface with the most energy loss will be found in the optical system. The energy value and polarization state of light reaching the image surface will also be available. These analysis methods are very helpful for designing or analyzing optical systems, such as analyzing the energy of stray light in high power optical systems, researching the influences of optical surfaces to rays' polarization state in polarization imaging systems and so on.

VIIRS/J1 polarization narrative

NASA Astrophysics Data System (ADS)

Waluschka, Eugene; McCorkel, Joel; McIntire, Jeff; Moyer, David; McAndrew, Brendan; Brown, Steven W.; Lykke, Keith R.; Young, James B.; Fest, Eric; Butler, James; Wang, Tung R.; Monroy, Eslim O.; Turpie, Kevin; Meister, Gerhard; Thome, Kurtis J.

2015-09-01

The polarization sensitivity of the Visible/NearIR (VISNIR) bands in the Joint Polar Satellite Sensor 1 (J1) Visible Infrared Imaging Radiometer Suite (VIIRS) instrument was measured using a broadband source. While polarization sensitivity for bands M5-M7, I1, and I2 was less than 2.5 %, the maximum polarization sensitivity for bands M1, M2, M3, and M4 was measured to be 6.4 %, 4.4 %, 3.1 %, and 4.3 %, respectively with a polarization characterization uncertainty of less than 0.38%. A detailed polarization model indicated that the large polarization sensitivity observed in the M1 to M4 bands is mainly due to the large polarization sensitivity introduced at the leading and trailing edges of the newly manufactured VISNIR bandpass focal plane filters installed in front of the VISNIR detectors. This was confirmed by polarization measurements of bands M1 and M4 bands using monochromatic light. Discussed are the activities leading up to and including the two polarization tests, some discussion of the polarization model and the model results, the role of the focal plane filters, the polarization testing of the Aft-Optics-Assembly, the testing of the polarizers at the National Aeronautics and Space Administration's (NASA) Goddard center and at the National Institute of Science and Technology (NIST) facility and the use of NIST's Traveling Spectral Irradiance and Radiance responsivity Calibrations using Uniform Sources (T-SIRCUS) for polarization testing and associated analyses and results.

A Thumb Carpometacarpal Joint Coordinate System Based on Articular Surface Geometry

PubMed Central

Halilaj, Eni; Rainbow, Michael J.; Got, Christopher; Moore, Douglas C.; Crisco, Joseph J.

2013-01-01

The thumb carpometacarpal (CMC) joint is a saddle-shaped articulation whose in vivo kinematics can be explored more accurately with computed tomography (CT) imaging methods than with previously used skin-based marker systems. These CT-based methods permit a detailed analysis of the morphology of the joint, and thus the prominent saddle-shaped geometry can be used to define a coordinate system that is inherently aligned with the primary directions of motion at the joint. The purpose of this study was to develop a CMC joint coordinate systems that is based on the computed principal directions of curvature on the trapezium and the first metacarpal. We evaluated the new coordinate system using bone surface models segmented from the CT scans of twenty-four healthy subjects. An analysis of sensitivity to the manual selection of articular surfaces resulted in mean orientation differences of 0.7±0.7° and mean location differences of 0.2±0.1mm. Inter-subject variability, which mostly emanates from anatomical differences, was evaluated with whole bone registration and resulted in mean orientation differences of 3.1±2.7° and mean location differences of 0.9±0.5mm. The proposed joint coordinate system addresses concerns of repeatability associated with bony landmark identification and provides a robust platform for describing the complex kinematics of the CMC joint. PMID:23357698

Calibration system with cryogenically-cooled loads for cosmic microwave background polarization detectors.

PubMed

Hasegawa, M; Tajima, O; Chinone, Y; Hazumi, M; Ishidoshiro, K; Nagai, M

2011-05-01

We present a novel system to calibrate millimeter-wave polarimeters for cosmic microwave background (CMB) polarization measurements. This technique is an extension of the conventional metal mirror rotation approach, however, it employs cryogenically-cooled blackbody absorbers. The primary advantage of this system is that it can generate a slightly polarized signal (∼100 mK) in the laboratory; this is at a similar level to that measured by ground-based CMB polarization experiments observing a ∼10 K sky. It is important to reproduce the observing condition in the laboratory for reliable characterization of polarimeters before deployment. In this paper, we present the design and principle of the system and demonstrate its use with a coherent-type polarimeter used for an actual CMB polarization experiment. This technique can also be applied to incoherent-type polarimeters and it is very promising for the next-generation CMB polarization experiments.

A photoacoustic tomography and ultrasound combined system for proximal interphalangeal joint imaging

NASA Astrophysics Data System (ADS)

Xu, Guan; Rajian, Justin R.; Girish, Gandikota; Wang, Xueding

2013-03-01

A photoacoustic (PA) and ultrasound (US) dual modality system for imaging human peripheral joints is introduced. The system utilizes a commercial US unit for both US control imaging and PA signal acquisition. Preliminary in vivo evaluation of the system on normal volunteers revealed that this system can recover both the structural and functional information of intra- and extra-articular tissues. Presenting both morphological and pathological information in joint, this system holds promise for diagnosis and characterization of inflammatory joint diseases such as rheumatoid arthritis.

Out of the blue: the evolution of horizontally polarized signals in Haptosquilla (Crustacea, Stomatopoda, Protosquillidae).

PubMed

How, Martin J; Porter, Megan L; Radford, Andrew N; Feller, Kathryn D; Temple, Shelby E; Caldwell, Roy L; Marshall, N Justin; Cronin, Thomas W; Roberts, Nicholas W

2014-10-01

The polarization of light provides information that is used by many animals for a number of different visually guided behaviours. Several marine species, such as stomatopod crustaceans and cephalopod molluscs, communicate using visual signals that contain polarized information, content that is often part of a more complex multi-dimensional visual signal. In this work, we investigate the evolution of polarized signals in species of Haptosquilla, a widespread genus of stomatopod, as well as related protosquillids. We present evidence for a pre-existing bias towards horizontally polarized signal content and demonstrate that the properties of the polarization vision system in these animals increase the signal-to-noise ratio of the signal. Combining these results with the increase in efficacy that polarization provides over intensity and hue in a shallow marine environment, we propose a joint framework for the evolution of the polarized form of these complex signals based on both efficacy-driven (proximate) and content-driven (ultimate) selection pressures. © 2014. Published by The Company of Biologists Ltd.

Analysis of the infrared detection system operating range based on polarization degree

NASA Astrophysics Data System (ADS)

Jiang, Kai; Liu, Wen; Liu, Kai; Duan, Jing; Yan, Pei-pei; Shan, Qiu-sha

2018-02-01

Infrared polarization detection technology has unique advantages in the field of target detection and identification because of using the polarization information of radiation. The mechanism of infrared polarization is introduced. Comparing with traditional infrared detection distance model, infrared detection operating range and Signal to Noise Ratio (SNR) model is built according to the polarization degree and noise. The influence of polarization degree on the SNR of infrared system is analyzed. At last, the basic condition of polarization detection SNR better than traditional infrared detection SNR is obtained.

Recycling, clustering, and endocytosis jointly maintain PIN auxin carrier polarity at the plasma membrane

PubMed Central

Kleine-Vehn, Jürgen; Wabnik, Krzysztof; Martinière, Alexandre; Łangowski, Łukasz; Willig, Katrin; Naramoto, Satoshi; Leitner, Johannes; Tanaka, Hirokazu; Jakobs, Stefan; Robert, Stéphanie; Luschnig, Christian; Govaerts, Willy; W Hell, Stefan; Runions, John; Friml, Jiří

2011-01-01

Cell polarity reflected by asymmetric distribution of proteins at the plasma membrane is a fundamental feature of unicellular and multicellular organisms. It remains conceptually unclear how cell polarity is kept in cell wall-encapsulated plant cells. We have used super-resolution and semi-quantitative live-cell imaging in combination with pharmacological, genetic, and computational approaches to reveal insights into the mechanism of cell polarity maintenance in Arabidopsis thaliana. We show that polar-competent PIN transporters for the phytohormone auxin are delivered to the center of polar domains by super-polar recycling. Within the plasma membrane, PINs are recruited into non-mobile membrane clusters and their lateral diffusion is dramatically reduced, which ensures longer polar retention. At the circumventing edges of the polar domain, spatially defined internalization of escaped cargos occurs by clathrin-dependent endocytosis. Computer simulations confirm that the combination of these processes provides a robust mechanism for polarity maintenance in plant cells. Moreover, our study suggests that the regulation of lateral diffusion and spatially defined endocytosis, but not super-polar exocytosis have primary importance for PIN polarity maintenance. PMID:22027551

Real-time Imaging Orientation Determination System to Verify Imaging Polarization Navigation Algorithm

PubMed Central

Lu, Hao; Zhao, Kaichun; Wang, Xiaochu; You, Zheng; Huang, Kaoli

2016-01-01

Bio-inspired imaging polarization navigation which can provide navigation information and is capable of sensing polarization information has advantages of high-precision and anti-interference over polarization navigation sensors that use photodiodes. Although all types of imaging polarimeters exist, they may not qualify for the research on the imaging polarization navigation algorithm. To verify the algorithm, a real-time imaging orientation determination system was designed and implemented. Essential calibration procedures for the type of system that contained camera parameter calibration and the inconsistency of complementary metal oxide semiconductor calibration were discussed, designed, and implemented. Calibration results were used to undistort and rectify the multi-camera system. An orientation determination experiment was conducted. The results indicated that the system could acquire and compute the polarized skylight images throughout the calibrations and resolve orientation by the algorithm to verify in real-time. An orientation determination algorithm based on image processing was tested on the system. The performance and properties of the algorithm were evaluated. The rate of the algorithm was over 1 Hz, the error was over 0.313°, and the population standard deviation was 0.148° without any data filter. PMID:26805851

Electron spin polarization by isospin ordering in correlated two-layer quantum Hall systems.

PubMed

Tiemann, L; Wegscheider, W; Hauser, M

2015-05-01

Enhancement of the electron spin polarization in a correlated two-layer, two-dimensional electron system at a total Landau level filling factor of 1 is reported. Using resistively detected nuclear magnetic resonance, we demonstrate that the electron spin polarization of two closely spaced two-dimensional electron systems becomes maximized when interlayer Coulomb correlations establish spontaneous isospin ferromagnetic order. This correlation-driven polarization dominates over the spin polarizations of competing single-layer fractional quantum Hall states under electron density imbalances.

Effect of cross-phase-modulation-induced polarization scattering on optical polarization mode dispersion compensation in wavelength-division-multiplexed systems

NASA Astrophysics Data System (ADS)

Xie, Chongjin; Möller, Lothar; Kilper, Daniel C.; Mollenauer, Linn F.

2003-12-01

Interchannel cross-phase-modulation-induced polarization scattering (XPMIPS) and its effect on the performance of optical polarization mode dispersion (PMD) compensation in wavelength-division-multiplexed (WDM) systems are studied. The level of XPMIPS in long-haul WDM transmission systems is theoretically quantified, and its effect on optical PMD compensation is evaluated with numerical simulations. We show that in 10-Gbit/s ultra-long-haul dense WDM systems XPMIPS could reduce the PMD compensation efficiency by 50%, whereas for 40-Gbit/s systems the effect of XPMIPS is smaller.

Photonic Choke-Joints for Dual Polarization Waveguides

NASA Technical Reports Server (NTRS)

Wollack, Edward J. (Inventor); U-Yen, Kongpop (Inventor); Chuss, David T. (Inventor)

2014-01-01

A waveguide structure for a dual polarization waveguide includes a first flange member, a second flange member, and a waveguide member disposed in each of the first flange member and second flange member. The first flange member and the second flange member are configured to be coupled together in a spaced-apart relationship separated by a gap. The first flange member has a substantially smooth surface, and the second flange member has an array of two-dimensional pillar structures formed therein.

Biomedical Polar Research Workshop Minutes

NASA Technical Reports Server (NTRS)

1990-01-01

This workshop was conducted to provide a background of NASA and National Science Foundation goals, an overview of previous and current biomedical research, and a discussion about areas of potential future joint activities. The objectives of the joint research were: (1) to develop an understanding of the physiological, psychological, and behavioral alterations and adaptations to extreme environments of the polar regions; (2) to ensure the health, well-being, and performance of humans in these environments; and (3) to promote the application of biomedical research to improve the quality of life in all environments.

Neural joint control for Space Shuttle Remote Manipulator System

NASA Technical Reports Server (NTRS)

Atkins, Mark A.; Cox, Chadwick J.; Lothers, Michael D.; Pap, Robert M.; Thomas, Charles R.

1992-01-01

Neural networks are being used to control a robot arm in a telerobotic operation. The concept uses neural networks for both joint and inverse kinematics in a robotic control application. An upper level neural network is trained to learn inverse kinematic mappings. The output, a trajectory, is then fed to the Decentralized Adaptive Joint Controllers. This neural network implementation has shown that the controlled arm recovers from unexpected payload changes while following the reference trajectory. The neural network-based decentralized joint controller is faster, more robust and efficient than conventional approaches. Implementations of this architecture are discussed that would relax assumptions about dynamics, obstacles, and heavy loads. This system is being developed to use with the Space Shuttle Remote Manipulator System.

Polarization-based index of refraction and reflection angle estimation for remote sensing applications.

PubMed

Thilak, Vimal; Voelz, David G; Creusere, Charles D

2007-10-20

A passive-polarization-based imaging system records the polarization state of light reflected by objects that are illuminated with an unpolarized and generally uncontrolled source. Such systems can be useful in many remote sensing applications including target detection, object segmentation, and material classification. We present a method to jointly estimate the complex index of refraction and the reflection angle (reflected zenith angle) of a target from multiple measurements collected by a passive polarimeter. An expression for the degree of polarization is derived from the microfacet polarimetric bidirectional reflectance model for the case of scattering in the plane of incidence. Using this expression, we develop a nonlinear least-squares estimation algorithm for extracting an apparent index of refraction and the reflection angle from a set of polarization measurements collected from multiple source positions. Computer simulation results show that the estimation accuracy generally improves with an increasing number of source position measurements. Laboratory results indicate that the proposed method is effective for recovering the reflection angle and that the estimated index of refraction provides a feature vector that is robust to the reflection angle.

Polarization-based index of refraction and reflection angle estimation for remote sensing applications

NASA Astrophysics Data System (ADS)

Thilak, Vimal; Voelz, David G.; Creusere, Charles D.

2007-10-01

A passive-polarization-based imaging system records the polarization state of light reflected by objects that are illuminated with an unpolarized and generally uncontrolled source. Such systems can be useful in many remote sensing applications including target detection, object segmentation, and material classification. We present a method to jointly estimate the complex index of refraction and the reflection angle (reflected zenith angle) of a target from multiple measurements collected by a passive polarimeter. An expression for the degree of polarization is derived from the microfacet polarimetric bidirectional reflectance model for the case of scattering in the plane of incidence. Using this expression, we develop a nonlinear least-squares estimation algorithm for extracting an apparent index of refraction and the reflection angle from a set of polarization measurements collected from multiple source positions. Computer simulation results show that the estimation accuracy generally improves with an increasing number of source position measurements. Laboratory results indicate that the proposed method is effective for recovering the reflection angle and that the estimated index of refraction provides a feature vector that is robust to the reflection angle.

Design considerations for bridge deck joint-sealing systems : summary report.

DOT National Transportation Integrated Search

1992-07-01

This is a report summary which summarizes a three year research effort related to the study of bridge deck expansion joint movements. Bridge deck expansion joint systems often develop serious problems requiring extensive and expensive maintenance. Th...

Measured Polarized Spectral Responsivity of JPSS J1 VIIRS Using the NIST T-SIRCUS

NASA Technical Reports Server (NTRS)

McIntire, Jeff; Young, James B.; Moyer, David; Waluschka, Eugene; Xiong, Xiaoxiong

2015-01-01

Recent pre-launch measurements performed on the Joint Polar Satellite System (JPSS) J1 Visible Infrared Imaging Radiometer Suite (VIIRS) using the National Institute of Standards and Technology (NIST) Traveling Spectral Irradiance and Radiance Responsivity Calibrations Using Uniform Sources (T-SIRCUS) monochromatic source have provided wavelength dependent polarization sensitivity for select spectral bands and viewing conditions. Measurements were made at a number of input linear polarization states (twelve in total) and initially at thirteen wavelengths across the bandpass (later expanded to seventeen for some cases). Using the source radiance information collected by an external monitor, a spectral responsivity function was constructed for each input linear polarization state. Additionally, an unpolarized spectral responsivity function was derived from these polarized measurements. An investigation of how the centroid, bandwidth, and detector responsivity vary with polarization state was weighted by two model input spectra to simulate both ground measurements as well as expected on-orbit conditions. These measurements will enhance our understanding of VIIRS polarization sensitivity, improve the design for future flight models, and provide valuable data to enhance product quality in the post-launch phase.

Calibration of polarimetric radar systems with good polarization isolation

NASA Technical Reports Server (NTRS)

Sarabandi, Kamal; Ulaby, Fawwaz T.; Tassoudji, M. Ali

1990-01-01

A practical technique is proposed for calibrating single-antenna polarimetric radar systems using a metal sphere plus any second target with a strong cross-polarized radar cross section. This technique assumes perfect isolation between antenna ports. It is shown that all magnitudes and phases (relative to one of the like-polarized linear polarization configurations) of the radar transfer function can be calibrated without knowledge of the scattering matrix of the second target. Comparison of the values measured (using this calibration technique) for a tilted cylinder at X-band with theoretical values shows agreement within + or - 0.3 dB in magnitude and + or - 5 degrees in phase. The radar overall cross-polarization isolation was 25 dB. The technique is particularly useful for calibrating a radar under field conditions, because it does not require the careful alignment of calibration targets.

Multi-Polarization Reconfigurable Antenna for Wireless Biomedical System.

PubMed

Wong, Hang; Lin, Wei; Huitema, Laure; Arnaud, Eric

2017-06-01

This paper presents a multi-polarization reconfigurable antenna with four dipole radiators for biomedical applications in body-centric wireless communication system (BWCS). The proposed multi-dipole antenna with switchable 0°, +45°, 90° and -45° linear polarizations is able to overcome the polarization mismatching and multi-path distortion in complex wireless channels as in BWCS. To realize this reconfigurable feature for the first time among all the reported antenna designs, we assembled four dipoles together with 45° rotated sequential arrangements. These dipoles are excited by the same feeding source provided by a ground tapered Balun. A metallic reflector is placed below the dipoles to generate a broadside radiation. By introducing eight PIN diodes as RF switches between the excitation source and the four dipoles, we can control a specific dipole to operate. As the results, 0°, +45°, 90° and -45° linear polarizations can be switched correspondingly to different operating dipoles. Experimental results agree with the simulation and show that the proposed antenna well works in all polarization modes with desirable electrical characteristics. The antenna has a wide impedance bandwidth of 34% from 2.2 to 3.1 GHz (for the reflection coefficient ≤ -10 dB) and exhibits a stable cardioid-shaped radiation pattern across the operating bandwidth with a peak gain of 5.2 dBi. To validate the effectiveness of the multi-dipole antenna for biomedical applications, we also designed a meandered PIFA as the implantable antenna. Finally, the communication link measurement shows that our proposed antenna is able to minimize the polarization mismatching and maintains the optimal communication link thanks to its polarization reconfigurability.

Preloaded joint analysis methodology for space flight systems

NASA Technical Reports Server (NTRS)

Chambers, Jeffrey A.

1995-01-01

This report contains a compilation of some of the most basic equations governing simple preloaded joint systems and discusses the more common modes of failure associated with such hardware. It is intended to provide the mechanical designer with the tools necessary for designing a basic bolted joint. Although the information presented is intended to aid in the engineering of space flight structures, the fundamentals are equally applicable to other forms of mechanical design.

Switchable thulium-doped fiber laser from polarization rotation vector to scalar soliton

NASA Astrophysics Data System (ADS)

Wu, Zhichao; Fu, Songnian; Jiang, Kai; Song, Jue; Li, Huizi; Tang, Ming; Shum, Ping; Liu, Deming

2016-10-01

We experimentally demonstrate switchable temporal soliton generation from a thulium-doped fiber laser (TDFL), using carbon nanotubes as the mode-locker. With the help of residual polarization dependent loss of a wavelength division multiplexer, a weak nonlinear polarization rotation (NPR) effect can be achieved within the laser cavity, which may provide joint contribution for passive mode-locking operation. By finely adjusting the polarization to alter the strength of NPR-based saturable absorption, the TDFL either approaches the operation regime of scalar soliton with strong NPR effect, or generates polarization rotation locked vector soliton (PRLVS) with weak NPR effect. The scalar solitons and PRLVSs possess 3-dB optical spectrum bandwidth of 2.2 nm and 2 nm, pulse-width of 1.8 ps and 2 ps, respectively. Moreover, the PRLVSs demonstrate a typical energy exchange between two polarized components on optical spectra and a period-doubling feature in time domain. Such operation principle can also be used in 1550 nm band fiber lasers and other nonlinear systems.

Switchable thulium-doped fiber laser from polarization rotation vector to scalar soliton

PubMed Central

Wu, Zhichao; Fu, Songnian; Jiang, Kai; Song, Jue; Li, Huizi; Tang, Ming; Shum, Ping; Liu, Deming

2016-01-01

We experimentally demonstrate switchable temporal soliton generation from a thulium-doped fiber laser (TDFL), using carbon nanotubes as the mode-locker. With the help of residual polarization dependent loss of a wavelength division multiplexer, a weak nonlinear polarization rotation (NPR) effect can be achieved within the laser cavity, which may provide joint contribution for passive mode-locking operation. By finely adjusting the polarization to alter the strength of NPR-based saturable absorption, the TDFL either approaches the operation regime of scalar soliton with strong NPR effect, or generates polarization rotation locked vector soliton (PRLVS) with weak NPR effect. The scalar solitons and PRLVSs possess 3-dB optical spectrum bandwidth of 2.2 nm and 2 nm, pulse-width of 1.8 ps and 2 ps, respectively. Moreover, the PRLVSs demonstrate a typical energy exchange between two polarized components on optical spectra and a period-doubling feature in time domain. Such operation principle can also be used in 1550 nm band fiber lasers and other nonlinear systems. PMID:27708427

Switchable thulium-doped fiber laser from polarization rotation vector to scalar soliton.

PubMed

Wu, Zhichao; Fu, Songnian; Jiang, Kai; Song, Jue; Li, Huizi; Tang, Ming; Shum, Ping; Liu, Deming

2016-10-06

We experimentally demonstrate switchable temporal soliton generation from a thulium-doped fiber laser (TDFL), using carbon nanotubes as the mode-locker. With the help of residual polarization dependent loss of a wavelength division multiplexer, a weak nonlinear polarization rotation (NPR) effect can be achieved within the laser cavity, which may provide joint contribution for passive mode-locking operation. By finely adjusting the polarization to alter the strength of NPR-based saturable absorption, the TDFL either approaches the operation regime of scalar soliton with strong NPR effect, or generates polarization rotation locked vector soliton (PRLVS) with weak NPR effect. The scalar solitons and PRLVSs possess 3-dB optical spectrum bandwidth of 2.2 nm and 2 nm, pulse-width of 1.8 ps and 2 ps, respectively. Moreover, the PRLVSs demonstrate a typical energy exchange between two polarized components on optical spectra and a period-doubling feature in time domain. Such operation principle can also be used in 1550 nm band fiber lasers and other nonlinear systems.

Joint Space Operations Center (JSpOC) Mission System Increment 3 (JMS Inc 3)

DTIC Science & Technology

2016-03-01

2016 Major Automated Information System Annual Report Joint Space Operations Center (JSpOC) Mission System Increment 3 (JMS Inc 3) Defense...1725 DSN Phone: DSN Fax: Date Assigned: May 16, 2014 Program Information Program Name Joint Space Operations Center (JSpOC) Mission System...approved program baseline; therefore, no Original Estimate has been established. JMS Inc 3 2016 MAR UNCLASSIFIED 4 Program Description The Joint Space

Antenna feed system for receiving circular polarization and transmitting linear polarization

NASA Technical Reports Server (NTRS)

Seidel, B. L.; Bathker, D. A. (Inventor)

1979-01-01

An invention is described which provides for receiving a circularly polarized signal from an antenna feed connected to orthogonally spaced antenna elements. It also provides for transmitting a linearly polarized signal through the same feed without switches, and without suffering a 3 dB polarization mismatch loss, using an arrangement of hybrid junctions. The arrangement is comprised of two dividing hybrid junctions, each connected to a different pair of antenna elements and a summing hybrid junction. In one version, a receiver is connected to the summing hybrid junction directly. A diplexer is used to connect a transmitter to only one pair of antenna elements. In another version, designated left and right circularly polarized (LCP and RCP) transmitters are connected to the summing hybrid junction by separate diplexers, and separate LCP and RCP sensitive receivers are connected to the diplexers in order to transmit linearly polarized signals using all four antenna elements while receiving circularly polarized signals as before. An orthomode junction and horn antenna may replace the two dividing hybrid junctions and antenna feed.

Enhancing the performance of coherent OTDR systems with polarization diversity complementary codes.

PubMed

Dorize, Christian; Awwad, Elie

2018-05-14

Monitoring the optical phase change in a fiber enables a wide range of applications where fast phase variations are induced by acoustic signals or by vibrations in general. However, the quality of the estimated fiber response strongly depends on the method used to modulate the light sent to the fiber and capture the variations of the optical field. In this paper, we show that distributed optical fiber sensing systems can advantageously exploit techniques from the telecommunication domain, as those used in coherent optical transmission, to enhance their performance in detecting mechanical events, while jointly offering a simpler setup than widespread pulse-cloning or spectral-sweep based schemes with acousto-optic modulators. We periodically capture an overall fiber Jones matrix estimate thanks to a novel probing technique using two mutually orthogonal complementary (Golay) pairs of binary sequences applied simultaneously in phase and quadrature on two orthogonal polarization states. A perfect channel response estimation of the sensor array is achieved, subject to conditions detailed in the paper, thus enhancing the sensitivity and bandwidth of coherent ϕ-OTDR systems. High sensitivity, linear response, and bandwidth coverage up to 18 kHz are demonstrated with a sensor array composed of 10 fiber Bragg gratings (FBGs).

Enhancing the performance of coherent OTDR systems with polarization diversity complementary codes

NASA Astrophysics Data System (ADS)

Dorize, Christian; Awwad, Elie

2018-05-01

Monitoring the optical phase change in a fiber enables a wide range of applications where fast phase variations are induced by acoustic signals or vibrations in general. However, the quality of the estimated fiber response strongly depends on the method used to modulate the light sent to the fiber and capture the variations of the optical field. In this paper, we show that distributed optical fiber sensing systems can advantageously exploit techniques from the telecommunication domain, as those used in coherent optical transmission, to enhance their performance in detecting mechanical events, while jointly offering a simpler setup than widespread pulse-cloning or spectral-sweep based schemes with acousto-optic modulators. We periodically capture an overall fiber Jones matrix estimate thanks to a novel probing technique using two mutually orthogonal complementary (Golay) pairs of binary sequences applied simultaneously in phase and quadrature on two orthogonal polarization states. A perfect channel response estimation of the sensor array is achieved, subject to conditions detailed in the paper, thus enhancing the sensitivity and bandwidth of coherent phase-OTDR systems. High sensitivity, linear response, and bandwidth coverage up to 18 kHz are demonstrated with a sensor array composed of 10 fiber Bragg gratings (FBGs).

The effects of load on system and lower-body joint kinetics during jump squats.

PubMed

Moir, Gavin L; Gollie, Jared M; Davis, Shala E; Guers, John J; Witmer, Chad A

2012-11-01

To investigate the effects of different loads on system and lower-body kinetics during jump squats, 12 resistance-trained men performed jumps under different loading conditions: 0%, 12%, 27%, 42%, 56%, 71%, and 85% of 1-repetition maximum (1-RM). System power output was calculated as the product of the vertical component of the ground reaction force and the vertical velocity of the bar during its ascent. Joint power output was calculated during bar ascent for the hip, knee, and ankle joints, and was also summed across the joints. System power output and joint power at knee and ankle joints were maximized at 0% 1-RM (p < 0.001) and followed the linear trends (p < 0.001) caused by power output decreasing as the load increased. Power output at the hip was maximized at 42% 1-RM (p = 0.016) and followed a quadratic trend (p = 0.030). Summed joint power could be predicted from system power (p < 0.05), while system power could predict power at the knee and ankle joints under some of the loading conditions. Power at the hip could not be predicted from system power. System power during loaded jumps reflects the power at the knee and ankle, while power at the hip does not correspond to system power.

[Development of polyaxial locking plate screw system of sacroiliac joint].

PubMed

Fan, Weijie; Xie, Xuesong; Zhou, Shuping; Zhang, Yonghu

2014-09-01

To develop an instrument for sacroiliac joint fixation with less injury and less complications. Firstly, 18 adult pelvic specimens (8 males and 10 females) were used to measure the anatomical data related to the locking plates and locking screws on the sacrum and ilium, and the polyaxial locking plate screw system of the sacroiliac joint was designed according to the anatomic data. This system was made of medical titanium alloy. Then 4 adult male plevic specimens were harvested and the experiment was divided into 3 groups: group A (normal pelvic), group B (the dislocated sacroiliac joint fixed with sacroiliac screws), and group C (the dislocated sacroiliac joint fixed with polyaxial locking plate screw system). The vertical displacement of sacroiliac joint under the condition of 0-700 N vertical load and the horizontal displacement on angle under the condition of 0-12 N·m torsional load were compared among the 3 groups by using the biological material test system. Finally, the simulated application test was performed on 1 adult male cadaveric specimen to observe soft tissue injury and the position of the locking plate and screw by X-ray films. According to the anatomic data of the sacrum and ilium, the polyaxial locking plate screw system of the sacroiliac joint was designed. The biomechanical results showed that the vertical displacement of the sacroiliac joint under the condition of 0-700 N vertical load in group A was significantly bigger than that in group B and group C (P < 0.05), but there was no significant difference between group B and group C (P > 0.05). The horizontal displacement on angle under the condition of 0-12 N·m torsional load in group A was significantly less than that in group B and group C (P < 0.05). The horizontal displacement on angle under the condition of 0-6 N·m torsional load in group B was bigger than that in group C, and the horizontal displacement on angle under the condition of 6-12 N·m torsional load in group B was less than

Ground System Extensibility Considerations

NASA Astrophysics Data System (ADS)

Miller, S. W.; Greene, E.

2017-12-01

The National Oceanic and Atmospheric Administration (NOAA) and National Aeronautics and Space Administration (NASA) are jointly acquiring the next-generation civilian weather and environmental satellite system: the Joint Polar Satellite System (JPSS). The Joint Polar Satellite System will replace the afternoon orbit component and ground processing system of the current Polar-orbiting Operational Environmental Satellites (POES) managed by NOAA. The JPSS satellites will carry a suite of sensors designed to collect meteorological, oceanographic, climatological and geophysical observations of the Earth. The ground processing system for JPSS is known as the JPSS Common Ground System (JPSS CGS). Developed and maintained by Raytheon Intelligence, Information and Services (IIS), the CGS is a multi-mission enterprise system serving NOAA, NASA and their national and international partners, such as NASA's Earth Observation System (EOS), NOAA's current POES, the Japan Aerospace Exploration Agency's (JAXA) Global Change Observation Mission - Water (GCOM-W1), and DoD's Defense Meteorological Satellite Program (DMSP). The CGS provides a wide range of support to a number of national and international missions, including command and control, mission management, data acquisition and routing, and environmental data processing and distribution. The current suite of CGS-supported missions has demonstrated the value of interagency and international partnerships to address global observation needs. With its established infrastructure and existing suite of missions, the CGS is extensible to a wider array of potential new missions. This paper will describe how the inherent scalability and extensibility of the CGS enables the addition of these new missions, with an eye on global enterprise needs in the 2020's and beyond.

Polarization effects on hard target calibration of lidar systems

NASA Technical Reports Server (NTRS)

Kavaya, Michael J.

1987-01-01

The theory of hard target calibration of lidar backscatter data, including laboratory measurements of the pertinent target reflectance parameters, is extended to include the effects of polarization of the transmitted and received laser radiation. The bidirectional reflectance-distribution function model of reflectance is expanded to a 4 x 4 matrix allowing Mueller matrix and Stokes vector calculus to be employed. Target reflectance parameters for calibration of lidar backscatter data are derived for various lidar system polarization configurations from integrating sphere and monostatic reflectometer measurements. It is found that correct modeling of polarization effects is mandatory for accurate calibration of hard target reflectance parameters and, therefore, for accurate calibration of lidar backscatter data.

Joint digital signal processing for superchannel coherent optical communication systems.

PubMed

Liu, Cheng; Pan, Jie; Detwiler, Thomas; Stark, Andrew; Hsueh, Yu-Ting; Chang, Gee-Kung; Ralph, Stephen E

2013-04-08

Ultra-high-speed optical communication systems which can support ≥ 1Tb/s per channel transmission will soon be required to meet the increasing capacity demand. However, 1Tb/s over a single carrier requires either or both a high-level modulation format (i.e. 1024QAM) and a high baud rate. Alternatively, grouping a number of tightly spaced "sub-carriers" to form a terabit superchannel increases channel capacity while minimizing the need for high-level modulation formats and high baud rate, which may allow existing formats, baud rate and components to be exploited. In ideal Nyquist-WDM superchannel systems, optical subcarriers with rectangular spectra are tightly packed at a channel spacing equal to the baud rate, thus achieving the Nyquist bandwidth limit. However, in practical Nyquist-WDM systems, precise electrical or optical control of channel spectra is required to avoid strong inter-channel interference (ICI). Here, we propose and demonstrate a new "super receiver" architecture for practical Nyquist-WDM systems, which jointly detects and demodulates multiple channels simultaneously and mitigates the penalties associated with the limitations of generating ideal Nyquist-WDM spectra. Our receiver-side solution relaxes the filter requirements imposed on the transmitter. Two joint DSP algorithms are developed for linear ICI cancellation and joint carrier-phase recovery. Improved system performance is observed with both experimental and simulation data. Performance analysis under different system configurations is conducted to demonstrate the feasibility and robustness of the proposed joint DSP algorithms.

System Wide Joint Position Sensor Fault Tolerance in Robot Systems Using Cartesian Accelerometers

NASA Technical Reports Server (NTRS)

Aldridge, Hal A.; Juang, Jer-Nan

1997-01-01

Joint position sensors are necessary for most robot control systems. A single position sensor failure in a normal robot system can greatly degrade performance. This paper presents a method to obtain position information from Cartesian accelerometers without integration. Depending on the number and location of the accelerometers. the proposed system can tolerate the loss of multiple position sensors. A solution technique suitable for real-time implementation is presented. Simulations were conducted using 5 triaxial accelerometers to recover from the loss of up to 4 joint position sensors on a 7 degree of freedom robot moving in general three dimensional space. The simulations show good estimation performance using non-ideal accelerometer measurements.

Cotton-type and joint invariants for linear elliptic systems.

PubMed

Aslam, A; Mahomed, F M

2013-01-01

Cotton-type invariants for a subclass of a system of two linear elliptic equations, obtainable from a complex base linear elliptic equation, are derived both by spliting of the corresponding complex Cotton invariants of the base complex equation and from the Laplace-type invariants of the system of linear hyperbolic equations equivalent to the system of linear elliptic equations via linear complex transformations of the independent variables. It is shown that Cotton-type invariants derived from these two approaches are identical. Furthermore, Cotton-type and joint invariants for a general system of two linear elliptic equations are also obtained from the Laplace-type and joint invariants for a system of two linear hyperbolic equations equivalent to the system of linear elliptic equations by complex changes of the independent variables. Examples are presented to illustrate the results.

Cotton-Type and Joint Invariants for Linear Elliptic Systems

PubMed Central

Aslam, A.; Mahomed, F. M.

2013-01-01

Cotton-type invariants for a subclass of a system of two linear elliptic equations, obtainable from a complex base linear elliptic equation, are derived both by spliting of the corresponding complex Cotton invariants of the base complex equation and from the Laplace-type invariants of the system of linear hyperbolic equations equivalent to the system of linear elliptic equations via linear complex transformations of the independent variables. It is shown that Cotton-type invariants derived from these two approaches are identical. Furthermore, Cotton-type and joint invariants for a general system of two linear elliptic equations are also obtained from the Laplace-type and joint invariants for a system of two linear hyperbolic equations equivalent to the system of linear elliptic equations by complex changes of the independent variables. Examples are presented to illustrate the results. PMID:24453871

Experimental determination of spin-dependent electron density by joint refinement of X-ray and polarized neutron diffraction data.

PubMed

Deutsch, Maxime; Claiser, Nicolas; Pillet, Sébastien; Chumakov, Yurii; Becker, Pierre; Gillet, Jean Michel; Gillon, Béatrice; Lecomte, Claude; Souhassou, Mohamed

2012-11-01

New crystallographic tools were developed to access a more precise description of the spin-dependent electron density of magnetic crystals. The method combines experimental information coming from high-resolution X-ray diffraction (XRD) and polarized neutron diffraction (PND) in a unified model. A new algorithm that allows for a simultaneous refinement of the charge- and spin-density parameters against XRD and PND data is described. The resulting software MOLLYNX is based on the well known Hansen-Coppens multipolar model, and makes it possible to differentiate the electron spins. This algorithm is validated and demonstrated with a molecular crystal formed by a bimetallic chain, MnCu(pba)(H(2)O)(3)·2H(2)O, for which XRD and PND data are available. The joint refinement provides a more detailed description of the spin density than the refinement from PND data alone.

A joint equalization algorithm in high speed communication systems

NASA Astrophysics Data System (ADS)

Hao, Xin; Lin, Changxing; Wang, Zhaohui; Cheng, Binbin; Deng, Xianjin

2018-02-01

This paper presents a joint equalization algorithm in high speed communication systems. This algorithm takes the advantages of traditional equalization algorithms to use pre-equalization and post-equalization. The pre-equalization algorithm takes the advantage of CMA algorithm, which is not sensitive to the frequency offset. Pre-equalization is located before the carrier recovery loop in order to make the carrier recovery loop a better performance and overcome most of the frequency offset. The post-equalization takes the advantage of MMA algorithm in order to overcome the residual frequency offset. This paper analyzes the advantages and disadvantages of several equalization algorithms in the first place, and then simulates the proposed joint equalization algorithm in Matlab platform. The simulation results shows the constellation diagrams and the bit error rate curve, both these results show that the proposed joint equalization algorithm is better than the traditional algorithms. The residual frequency offset is shown directly in the constellation diagrams. When SNR is 14dB， the bit error rate of the simulated system with the proposed joint equalization algorithm is 103 times better than CMA algorithm, 77 times better than MMA equalization, and 9 times better than CMA-MMA equalization.

Background for Joint Systems Aspects of AIR 6000

DTIC Science & Technology

2000-04-01

Checkland’s Soft Systems Methodology [7, 8,9]. The analytical techniques that are proposed for joint systems work are based on calculating probability...Supporting Global Interests 21 DSTO-CR-0155 SLMP Structural Life Management Plan SOW Stand-Off Weapon SSM Soft Systems Methodology UAV Uninhabited Aerial... Systems Methodology in Action, John Wiley & Sons, Chichester, 1990. [101 Pearl, Judea, Probabilistic Reasoning in Intelligent Systems: Networks of Plausible

Polarized hyperspectral imaging system for in vivo detection of vulvar lichen sclerosis

NASA Astrophysics Data System (ADS)

Qu, Yingjie; Ren, Wenqi; Liu, Songde; Liu, Peng; Xie, Lan; Zhang, Xiaoyuan; Zhang, Shiwu; Chang, Shufang; Xu, Ronald

2016-03-01

Vulvar lichen sclerosis (VLS) is a chronic, inflammatory and mucocutaneous disease of extragenital skin, which often goes undetected for years. The underlying causes are associated with the decrease of VEGF that reduces the blood oxygenation of vulva and the structural changes in the collagen fibrils, which can lead to scarring of the affected area. However, few methods are available for quantitative detection of VLS. Clinician's examinations are subjective and may lead to misdiagnosis. Spectroscopy is a potentially effective method for noninvasive detection of VLS. In this paper, we developed a polarized, hyperspectral imaging system for quantitative assessment. The system utilized a hyperspectral camera to collect the reflectance images of the entire vulva under Xenon lamp illumination with and without a polarizer in front of the fiber. One image (Ipar) acquired with the AOTF parallel to the polarization of illumination and the other image (Iper) acquired with the AOTF perpendicular to the illumination. This paper compares polarized images of VLS in a pilot clinical study. The collected reflectance data under Xenon lamp illumination without a polarizer are calibrated and the hyperspectral signals are extracted. An IRB approved clinical trial was carried out to evaluate the clinical utility for VLS detection. Our pilot study has demonstrated the technical potential of using this polarized hyperspectral imaging system for in vivo detection of vulvar lichen sclerosis.

Active imaging with the aids of polarization retrieve in turbid media system

NASA Astrophysics Data System (ADS)

Tao, Qiangqiang; Sun, Yongxuan; Shen, Fei; Xu, Qiang; Gao, Jun; Guo, Zhongyi

2016-01-01

We propose a novel active imaging based on the polarization retrieve (PR) method in turbid media system. In our simulations, the Monte Carlo (MC) algorithm has been used to investigate the scattering process between the incident photons and the scattering particles, and the visually concordant object but with different polarization characteristics in different regions, has been selected as the original target that is placed in the turbid media. Under linearly and circularly polarized illuminations, the simulation results demonstrate that the corresponding polarization properties can provide additional information for the imaging, and the contrast of the polarization image can also be enhanced greatly compared to the simplex intensity image in the turbid media. Besides, the polarization image adjusted by the PR method can further enhance the visibility and contrast. In addition, by PR imaging method, with the increasing particles' size in Mie's scale, the visibility can be enhanced, because of the increased forward scattering effect. In general, in the same circumstance, the circular polarization images can offer a better contrast and visibility than that of linear ones. The results indicate that the PR imaging method is more applicable to the scattering media system with relatively larger particles such as aerosols, heavy fog, cumulus, and seawater, as well as to biological tissues and blood media.

Polarization-dependent plasmonic photocurrents in two-dimensional electron systems

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

Popov, V. V., E-mail: popov-slava@yahoo.co.uk; Saratov State University, Saratov 410012; Saratov Scientific Center of the Russian Academy of Sciences, Saratov 410028

2016-06-27

Plasmonic polarization dependent photocurrents in a homogeneous two-dimensional electron system are studied. Those effects are completely different from the photon drag and electronic photogalvanic effects as well as from the plasmonic ratchet effect in a density modulated two-dimensional electron system. Linear and helicity-dependent contributions to the photocurrent are found. The linear contribution can be interpreted as caused by the longitudinal and transverse plasmon drag effect. The helicity-dependent contribution originates from the non-linear electron convection and changes its sign with reversing the plasmonic field helicity. It is shown that the helicity-dependent component of the photocurrent can exceed the linear one bymore » several orders of magnitude in high-mobility two-dimensional electron systems. The results open possibilities for all-electronic detection of the radiation polarization states by exciting the plasmonic photocurrents in two-dimensional electron systems.« less

The multi-spectral line-polarization MSE system on Alcator C-Mod

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

Mumgaard, R. T., E-mail: mumgaard@psfc.mit.edu; Khoury, M.; Scott, S. D.

A multi-spectral line-polarization motional Stark effect (MSE-MSLP) diagnostic has been developed for the Alcator C-Mod tokamak wherein the Stokes vector is measured in multiple wavelength bands simultaneously on the same sightline to enable better polarized background subtraction. A ten-sightline, four wavelength MSE-MSLP detector system was designed, constructed, and qualified. This system consists of a high-throughput polychromator for each sightline designed to provide large étendue and precise spectral filtering in a cost-effective manner. Each polychromator utilizes four narrow bandpass interference filters and four custom large diameter avalanche photodiode detectors. Two filters collect light to the red and blue of the MSEmore » emission spectrum while the remaining two filters collect the beam pi and sigma emission generated at the same viewing volume. The filter wavelengths are temperature tuned using custom ovens in an automated manner. All system functions are remote controllable and the system can be easily retrofitted to existing single-wavelength line-polarization MSE systems.« less

The multi-spectral line-polarization MSE system on Alcator C-Mod

DOE PAGES

Mumgaard, R. T.; Scott, S. D.; Khoury, M.

2016-08-17

A multi-spectral line-polarization motional Stark effect (MSE-MSLP) diagnostic has been developed for the Alcator C-Mod tokamak wherein the Stokes vector is measured in multiple wavelength bands simultaneously on the same sightline to enable better polarized background subtraction. A ten-sightline, four wavelength MSE-MSLP detector system was designed, constructed, and qualified. This system consists of a high-throughput polychromator for each sightline designed to provide large étendue and precise spectral filtering in a cost-effective manner. Each polychromator utilizes four narrow bandpass interference filters and four custom large diameter avalanche photodiode detectors. Two filters collect light to the red and blue of the MSEmore » emission spectrum while the remaining two filters collect the beam pi and sigma emission generated at the same viewing volume. The filter wavelengths are temperature tuned using custom ovens in an automated manner. Furthermore, all system functions are remote controllable and the system can be easily retrofitted to existing single-wavelength line-polarization MSE systems.« less

Systems engineering in a joint program environment: the joint helmet-mounted cueing system

NASA Astrophysics Data System (ADS)

Wilkins, Donald F.

1999-07-01

The Joint Helmet Mounted Cueing System (JHMCS) is a design program involving two airframe companies (Boeing and Lockheed Martin), two services (USAF and USN) and four aircraft platforms: the F-22, the F-16, the F/A-18 and the F-15. Developing equipment requirements for the combined operational and environmental needs of these diverse communities is a significant challenge. In addition, the team is geographically dispersed which presented challenges in communication and coordination. This paper details the lessons learned in producing a cost-effective design within a short development schedule and makes recommendations for future development programs.

Distributed vibration fiber sensing system based on Polarization Diversity Receiver

NASA Astrophysics Data System (ADS)

Zhang, Junan; Jiang, Peng; Hu, Zhengliang; Hu, Yongming

2016-10-01

In this paper, we propose a distributed vibration fiber sensing system based on Polarization Diversity Receiver(PDR). We use Acoustic Optical Modulator(AOM) to generate pulse light and an unbalanced M-Z interferometer to generate two pulse light with a certain time delay in the same period. As the pulse lights propagating in fibers, the Backward Rayleigh scattering lights will interfere with each other. The vibration on the fiber will change the length and refractive index of fiber which results in the change of the phase of the interference signal. Hence, one arm of the M-Z interferometer is modulated by a sinusoidal phase-generated carrier(PGC) signal, and PGC demodulation algorithm has been used to acquire phase information from the Backward Rayleigh scattering lights. In order to overcome the influence of polarization-induced fading and enhance Signal Noise Ratio(SNR), we set a PDR before the photo detector. The Polarization Diversity Receiver segregates the interfere light into two lights with orthogonal states of polarization. Hence, there is always one channel has a better interfere light signal. The experiments are presented to verify the effectiveness of the distributed vibration fiber sensing system proposed.

Analysis of JPSS J1 VIIRS Polarization Sensitivity Using the NIST T-SIRCUS

NASA Technical Reports Server (NTRS)

McIntire, Jeffrey W.; Young, James B.; Moyer, David; Waluschka, Eugene; Oudrari, Hassan; Xiong, Xiaoxiong

2015-01-01

The polarization sensitivity of the Joint Polar Satellite System (JPSS) J1 Visible Infrared Imaging Radiometer Suite (VIIRS) measured pre-launch using a broadband source was observed to be larger than expected for many reflective bands. Ray trace modeling predicted that the observed polarization sensitivity was the result of larger diattenuation at the edges of the focal plane filter spectral bandpass. Additional ground measurements were performed using a monochromatic source (the NIST T-SIRCUS) to input linearly polarized light at a number of wavelengths across the bandpass of two VIIRS spectral bands and two scan angles. This work describes the data processing, analysis, and results derived from the T-SIRCUS measurements, comparing them with broadband measurements. Results have shown that the observed degree of linear polarization, when weighted by the sensor's spectral response function, is generally larger on the edges and smaller in the center of the spectral bandpass, as predicted. However, phase angle changes in the center of the bandpass differ between model and measurement. Integration of the monochromatic polarization sensitivity over wavelength produced results consistent with the broadband source measurements, for all cases considered.

Study on the measurement system of the target polarization characteristics and test

NASA Astrophysics Data System (ADS)

Fu, Qiang; Zhu, Yong; Zhang, Su; Duan, Jin; Yang, Di; Zhan, Juntong; Wang, Xiaoman; Jiang, Hui-Lin

2015-10-01

The polarization imaging detection technology increased the polarization information on the basis of the intensity imaging, which is extensive application in the military and civil and other fields, the research on the polarization characteristics of target is particularly important. The research of the polarization reflection model was introduced in this paper, which describes the scattering vector light energy distribution in reflecting hemisphere polarization characteristics, the target polarization characteristics test system solutions was put forward, by the irradiation light source, measuring turntable and camera, etc, which illuminate light source shall direct light source, with laser light sources and xenon lamp light source, light source can be replaced according to the test need; Hemispherical structure is used in measuring circumarotate placed near its base material sample, equipped with azimuth and pitching rotation mechanism, the manual in order to adjust the azimuth Angle and high Angle observation; Measuring camera pump works, through the different in the way of motor control polaroid polarization test, to ensure the accuracy of measurement and imaging resolution. The test platform has set up by existing laboratory equipment, the laser is 532 nm, line polaroid camera, at the same time also set the sending and receiving optical system. According to the different materials such as wood, metal, plastic, azimuth Angle and zenith Angle in different observation conditions, measurement of target in the polarization scattering properties of different exposure conditions, implementation of hemisphere space pBRDF measurement.

Optimised robot-based system for the exploration of elastic joint properties.

PubMed

Frey, M; Burgkart, R; Regenfelder, F; Riener, R

2004-09-01

Numerous publications provide measured biomechanical data relating to synovial joints. However, in general, they do not reflect the non-linear elastic joint properties in detail or do not consider all degrees of freedom (DOF), or the quantity of data is sparse. To perform more comprehensive, extended measurements of elastic joint properties, an optimised robot-based approach was developed. The basis was an industrial, high-precision robot that was capable of applying loads to the joint and measuring the joint displacement in 6 DOF. The system was equipped with novel, custom-made control hardware. In contrast to the commonly used sampling rates that are below 100 Hz, a rate of 4 kHz was realised for each DOF. This made it possible to implement advanced, highly dynamic, quasi-continuous closed-loop controllers. Thus oscillations of the robot were avoided, and measurements were speeded up. The stiffness of the entire system was greater than 44 kNm(-1) and 22 Nm deg(-1), and the maximum difference between two successive measurements was less than 0.5 deg. A sophisticated CT-based referencing routine facilitated the matching of kinematic data with the individual anatomy of the tested joint. The detailed detection of the elastic varus-valgus properties of a human knee joint is described, and the need for high spatial resolution is demonstrated.

Flight set 360L007 (STS-33R) field joint protection system, thermal protection system, and systems tunnel components, volume 7

NASA Technical Reports Server (NTRS)

1990-01-01

The performance of the thermal protection system, field joint protection system, and systems tunnel components of flight set 360L007 is presented as evaluated by postflight hardware inspection. The condition of both motors was similar to previous flights. Four aft edge strikes were noted on the ground environment instrumentation thermal protection system. The hits all left a clean substrate, indicating that the damage was caused by nozzle severance debris and/or water impact. No National Space Transportation System debris criteria for missing thermal protection system were violated. Two problem reports were written against the field joint protection system. The first concerned two cracks in the K5NA closeout over the trunnion/vent valve location on the left-hand aft field joint. A similar condition was observed on Flight 5 (360H005). The second problem report referred to a number of small surface cracks between two impact marks on the left-hand forward field joint. Neither area exhibited loose material or any abnormal heat effects, and they have no impact on flight safety.

Dynamic modeling and optimal joint torque coordination of advanced robotic systems

NASA Astrophysics Data System (ADS)

Kang, Hee-Jun

The development is documented of an efficient dynamic modeling algorithm and the subsequent optimal joint input load coordination of advanced robotic systems for industrial application. A closed-form dynamic modeling algorithm for the general closed-chain robotic linkage systems is presented. The algorithm is based on the transfer of system dependence from a set of open chain Lagrangian coordinates to any desired system generalized coordinate set of the closed-chain. Three different techniques for evaluation of the kinematic closed chain constraints allow the representation of the dynamic modeling parameters in terms of system generalized coordinates and have no restriction with regard to kinematic redundancy. The total computational requirement of the closed-chain system model is largely dependent on the computation required for the dynamic model of an open kinematic chain. In order to improve computational efficiency, modification of an existing open-chain KIC based dynamic formulation is made by the introduction of the generalized augmented body concept. This algorithm allows a 44 pct. computational saving over the current optimized one (O(N4), 5995 when N = 6). As means of resolving redundancies in advanced robotic systems, local joint torque optimization is applied for effectively using actuator power while avoiding joint torque limits. The stability problem in local joint torque optimization schemes is eliminated by using fictitious dissipating forces which act in the necessary null space. The performance index representing the global torque norm is shown to be satisfactory. In addition, the resulting joint motion trajectory becomes conservative, after a transient stage, for repetitive cyclic end-effector trajectories. The effectiveness of the null space damping method is shown. The modular robot, which is built of well defined structural modules from a finite-size inventory and is controlled by one general computer system, is another class of evolving

2011 Joint Science Education Project: Research Experience in Polar Science

NASA Astrophysics Data System (ADS)

Wilkening, J.; Ader, V.

2011-12-01

The Joint Science Education Project (JSEP), sponsored by the National Science Foundation, is a two-part program that brings together students and teachers from the United States, Greenland, and Denmark, for a unique cross-cultural, first-hand experience of the realities of polar science field research in Greenland. During JSEP, students experienced research being conducted on and near the Greenland ice sheet by attending researcher presentations, visiting NSF-funded field sites (including Summit and NEEM field stations, both located on the Greenland ice sheet), and designing and conducting research projects in international teams. The results of two of these projects will be highlighted. The atmospheric project investigated the differences in CO2, UVA, UVB, temperature, and albedo in different Arctic microenvironments, while also examining the interaction between the atmosphere and water present in the given environments. It was found that the carbon dioxide levels varied: glacial environments having the lowest levels, with an average concentration of 272.500 ppm, and non-vegetated, terrestrial environments having the highest, with an average concentration of 395.143 ppm. Following up on these results, it is planned to further investigate the interaction of the water and atmosphere, including water's role in the uptake of carbon dioxide. The ecology project investigated the occurrence of unusual large blooms of Nostoc cyanobacteria in Kangerlussuaq area lakes. The water chemistry of the lakes which contained the cyanobacteria and the lakes that did not were compared. The only noticeable difference was of the lakes' acidity, lakes containing the blooms had an average pH value of 8.58, whereas lakes without the blooms had an average pH value of 6.60. Further investigation of these results is needed to determine whether or not this was a cause or effect of the cyanobacteria blooms. As a next step, it is planned to attempt to grow the blooms to monitor their effects on

Selection of optimal multispectral imaging system parameters for small joint arthritis detection

NASA Astrophysics Data System (ADS)

Dolenec, Rok; Laistler, Elmar; Stergar, Jost; Milanic, Matija

2018-02-01

Early detection and treatment of arthritis is essential for a successful outcome of the treatment, but it has proven to be very challenging with existing diagnostic methods. Novel methods based on the optical imaging of the affected joints are becoming an attractive alternative. A non-contact multispectral imaging (MSI) system for imaging of small joints of human hands and feet is being developed. In this work, a numerical simulation of the MSI system is presented. The purpose of the simulation is to determine the optimal design parameters. Inflamed and unaffected human joint models were constructed with a realistic geometry and tissue distributions, based on a MRI scan of a human finger with a spatial resolution of 0.2 mm. The light transport simulation is based on a weighted-photon 3D Monte Carlo method utilizing CUDA GPU acceleration. An uniform illumination of the finger within the 400-1100 nm spectral range was simulated and the photons exiting the joint were recorded using different acceptance angles. From the obtained reflectance and transmittance images the spectral and spatial features most indicative of inflammation were identified. Optimal acceptance angle and spectral bands were determined. This study demonstrates that proper selection of MSI system parameters critically affects ability of a MSI system to discriminate the unaffected and inflamed joints. The presented system design optimization approach could be applied to other pathologies.

2000 Worldwide Joint Lessons Learned Conference. Forging a Future Joint Lessons Learned System. (Joint Center for Lessons Learned Special Bulletin. Volume 3, Special Issue 1, January 2001)

DTIC Science & Technology

2001-01-01

Management System (JTIMS) followed, and generated spirited discussion regarding the respective roles of JTIMS and the JLLP. The discussion concluded...waiting for the Director, Joint Staff�s signature and should be in official distribution by January 2001. An update on the Joint Training Information

The control system of the polarized internal target of ANKE at COSY

NASA Astrophysics Data System (ADS)

Kleines, H.; Sarkadi, J.; Zwoll, K.; Engels, R.; Grigoryev, K.; Mikirtychyants, M.; Nekipelov, M.; Rathmann, F.; Seyfarth, H.; Kravtsov, P.; Vasilyev, A.

2006-05-01

The polarized internal target for the ANKE experiment at the Cooler Synchrotron COSY of the Forschungszentrum Jülich utilizes a polarized atomic beam source to feed a storage cell with polarized hydrogen or deuterium atoms. The nuclear polarization is measured with a Lamb-shift polarimeter. For common control of the two systems, industrial equipment was selected providing reliable, long-term support and remote control of the target as well as measurement and optimization of its operating parameters. The interlock system has been implemented on the basis of SIEMENS SIMATIC S7-300 family of programmable logic controllers. In order to unify the interfacing to the control computer, all front-end equipment is connected via the PROFIBUS DP fieldbus. The process control software was implemented using the Windows-based WinCC toolkit from SIEMENS. The variety of components, to be controlled, and the logical structure of the control and interlock system are described. Finally, a number of applications derived from the present development to other, new installations are briefly mentioned.

A Systems Biology Approach to Synovial Joint Lubrication in Health, Injury, and Disease

PubMed Central

Hui, Alexander Y.; McCarty, William J.; Masuda, Koichi; Firestein, Gary S.; Sah, Robert L.

2013-01-01

The synovial joint contains synovial fluid (SF) within a cavity bounded by articular cartilage and synovium. SF is a viscous fluid that has lubrication, metabolic, and regulatory functions within synovial joints. SF contains lubricant molecules, including proteoglycan-4 and hyaluronan. SF is an ultrafiltrate of plasma with secreted contributions from cell populations lining and within the synovial joint space, including chondrocytes and synoviocytes. Maintenance of normal SF lubricant composition and function are important for joint homeostasis. In osteoarthritis, rheumatoid arthritis, and joint injury, changes in lubricant composition and function accompany alterations in the cytokine and growth factor environment and increased fluid and molecular transport through joint tissues. Thus, understanding the synovial joint lubrication system requires a multi-faceted study of the various parts of the synovial joint and their interactions. Systems biology approaches at multiple scales are being used to describe the molecular, cellular, and tissue components and their interactions that comprise the functioning synovial joint. Analyses of the transcriptome and proteome of SF, cartilage, and synovium suggest that particular molecules and pathways play important roles in joint homeostasis and disease. Such information may be integrated with physicochemical tissue descriptions to construct integrative models of the synovial joint that ultimately may explain maintenance of health, recovery from injury, or development and progression of arthritis. PMID:21826801

Flight Set 360L006 STS-34 field joint protection system, thermal protection system, and systems tunnel components, volume 4

NASA Technical Reports Server (NTRS)

Wilkinson, J. P.

1990-01-01

The performance of the thermal protection system, field joint protection system, and systems tunnel components of Flight Set 360L006, are documented, as evaluated by postflight hardware inspection. The condition of both motors was similar to previous flights. Sixteen aft edge hits were noted on the ground environment instrumentation thermal protection system. Each hit left a clean substrate, indicating that the damage was caused by nozzle severance debris and/or water impact. No National Space and Transporation System debris criteria for missing thermal protection system were violated. One 5.0 by 1.0 in. unbond was observed on the left hand center field joint K5NA closeout and was elevated to an in-flight anomaly (STS-34-M-4) by the NASA Ice/Debris team. Aft edge damage to the K5NA and an associated black streak indicate that burning debris from the nozzle severance system was the likely cause of the damage. Minor divots caused by debris were seen on previous flights, but this is the first occurrence of a K5NA unbond. Since the unbond occurred after booster separation there is no impact on flight safety and no corrective actions was taken. The right hand center field joint primary heater failed the dielectric withstanding voltage test after joint closeout. The heater was then disabled by opening the circuit breaker, and the redundant heater was used. The redundant heater performed nominally during the launch countdown. A similar condition occurred on Flight 4 when a secondary joint heater failed the dielectric withstanding voltage test.

Polarized Solid State Target

NASA Astrophysics Data System (ADS)

Dutz, Hartmut; Goertz, Stefan; Meyer, Werner

2017-01-01

The polarized solid state target is an indispensable experimental tool to study single and double polarization observables at low intensity particle beams like tagged photons. It was one of the major components of the Crystal-Barrel experiment at ELSA. Besides the operation of the 'CB frozen spin target' within the experimental program of the Crystal-Barrel collaboration both collaborative groups of the D1 project, the polarized target group of the Ruhr Universität Bochum and the Bonn polarized target group, have made significant developments in the field of polarized targets within the CRC16. The Bonn polarized target group has focused its work on the development of technically challenging polarized solid target systems towards the so called '4π continuous mode polarized target' to operate them in combination with 4π-particle detection systems. In parallel, the Bochum group has developed various highly polarized deuterated target materials and high precision NMR-systems, in the meantime used for polarization experiments at CERN, JLAB and MAMI, too.

Theoretical and experimental studies of polarization fluctuations over atmospheric turbulent channels for wireless optical communication systems.

PubMed

Zhang, Jiankun; Ding, Shengli; Zhai, Huili; Dang, Anhong

2014-12-29

In wireless optical communications (WOC), polarization multiplexing systems and coherent polarization systems have excellent performance and wide applications, while its state of polarization affected by atmospheric turbulence is not clearly understood. This paper focuses on the polarization fluctuations caused by atmospheric turbulence in a WOC link. Firstly, the relationship between the polarization fluctuations and the index of refraction structure parameter is introduced and the distribution of received polarization angle is obtained through theoretical derivations. Then, turbulent conditions are adjusted and measured elaborately in a wide range of scintillation indexes (SI). As a result, the root-mean-square (RMS) variation and probability distribution function (PDF) of polarization angle conforms closely to that of theoretical model.

How weak values emerge in joint measurements on cloned quantum systems.

PubMed

Hofmann, Holger F

2012-07-13

A statistical analysis of optimal universal cloning shows that it is possible to identify an ideal (but nonpositive) copying process that faithfully maps all properties of the original Hilbert space onto two separate quantum systems, resulting in perfect correlations for all observables. The joint probabilities for noncommuting measurements on separate clones then correspond to the real parts of the complex joint probabilities observed in weak measurements on a single system, where the measurements on the two clones replace the corresponding sequence of weak measurement and postselection. The imaginary parts of weak measurement statics can be obtained by replacing the cloning process with a partial swap operation. A controlled-swap operation combines both processes, making the complete weak measurement statistics accessible as a well-defined contribution to the joint probabilities of fully resolved projective measurements on the two output systems.

Modified Denavit-Hartenberg parameters for better location of joint axis systems in robot arms

NASA Technical Reports Server (NTRS)

Barker, L. K.

1986-01-01

The Denavit-Hartenberg parameters define the relative location of successive joint axis systems in a robot arm. A recent justifiable criticism is that one of these parameters becomes extremely large when two successive joints have near-parallel rotational axes. Geometrically, this parameter then locates a joint axis system at an excessive distance from the robot arm and, computationally, leads to an ill-conditioned transformation matrix. In this paper, a simple modification (which results from constraining a transverse vector between successive joint rotational axes to be normal to one of the rotational axes, instead of both) overcomes this criticism and favorably locates the joint axis system. An example is given for near-parallel rotational axes of the elbow and shoulder joints in a robot arm. The regular and modified parameters are extracted by an algebraic method with simulated measurement data. Unlike the modified parameters, extracted values of the regular parameters are very sensitive to measurement accuracy.

The National Polar-orbiting Operational Environmental Satellite System

NASA Astrophysics Data System (ADS)

Bloom, H.

The tri-agency Integrated Program Office (IPO) is responsible for managing the development of the National Polar-orbiting Operational Environmental Satellite System (NPOESS). NPOESS will replace the current military and civilian operational polar-orbiting ``weather'' satellites. The Northrop Grumman Space Technology - Raytheon team was competitively selected in 2002 as the Acquisition and Operations contractor team to develop, integrate, deploy, and operate NPOESS satellites to meet the tri-agency user requirements for NPOESS over the 10-year (2009-2018) operational life of the program. Beginning in 2009, NPOESS spacecraft will be launched into three orbital planes to provide significantly improved operational capabilities and benefits to satisfy critical civil and national security requirements for space-based, remotely sensed environmental data. With the development of NPOESS, we are evolving operational ``weather'' satellites into integrated environmental observing systems by expanding our capabilities to observe, assess, and predict the total Earth system - atmosphere, ocean, land, and the space environment. In recent years, the operational weather forecasting and climate science communities have levied more rigorous requirements on space-based observations of the Earth's system that have significantly increased demands on performance of the instruments, spacecraft, and ground systems required to deliver NPOESS data, products, and information to end users. The ``end-to-end'' system consists of: the spacecraft; instruments and sensors on the spacecraft; launch support capabilities; the command, control, communications, and data routing infrastructure; and data processing hardware and software. NPOESS will observe significantly more phenomena simultaneously from space than its operational predecessors. NPOESS is expected to deliver large volumes of more accurate measurements at higher spatial (horizontal and vertical) and temporal resolution at much higher data

A polarization sensitive hyperspectral imaging system for detection of differences in tissue properties

NASA Astrophysics Data System (ADS)

Peller, Joseph A.; Ceja, Nancy K.; Wawak, Amanda J.; Trammell, Susan R.

2018-02-01

Polarized light imaging and optical spectroscopy can be used to distinguish between healthy and diseased tissue. In this study, the design and testing of a single-pixel hyperspectral imaging system that uses differences in the polarization of light reflected from tissue to differentiate between healthy and thermally damaged tissue is discussed. Thermal lesions were created in porcine skin (n = 8) samples using an IR laser. The damaged regions were clearly visible in the polarized light hyperspectral images. Reflectance hyperspectral and white light imaging was also obtained for all tissue samples. Sizes of the thermally damaged regions as measured via polarized light hyperspectral imaging are compared to sizes of these regions as measured in the reflectance hyperspectral images and white light images. Good agreement between the sizes measured by all three imaging modalities was found. Hyperspectral polarized light imaging can differentiate between healthy and damaged tissue. Possible applications of this imaging system include determination of tumor margins during cancer surgery or pre-surgical biopsy.

Analysis on Sealing Reliability of Bolted Joint Ball Head Component of Satellite Propulsion System

NASA Astrophysics Data System (ADS)

Guo, Tao; Fan, Yougao; Gao, Feng; Gu, Shixin; Wang, Wei

2018-01-01

Propulsion system is one of the important subsystems of satellite, and its performance directly affects the service life, attitude control and reliability of the satellite. The Paper analyzes the sealing principle of bolted joint ball head component of satellite propulsion system and discuss from the compatibility of hydrazine anhydrous and bolted joint ball head component, influence of ground environment on the sealing performance of bolted joint ball heads, and material failure caused by environment, showing that the sealing reliability of bolted joint ball head component is good and the influence of above three aspects on sealing of bolted joint ball head component can be ignored.

Polar Satcom System and Related Method

NASA Technical Reports Server (NTRS)

Mitchell, James P. (Inventor)

2016-01-01

A system and method for communication relay via a repeater platform satellite vehicle to a near surface station in the Polar Region is disclosed. A preferred embodiment receives a plurality of positioning and content data from a plurality of constellations of Geosynchronous Equatorial Orbit (GEO) Satellite Vehicles (SAT). Additionally, the system receives a plurality of position, time and altitude data from constellations of available repeater platform (RP) SATs. The system receives a request for content from a near surface station located in an area lacking adequate line-of-sight to the GEO based signal. The system aligns antenna elements onboard the desired RP SATs to amplify and relay the GEO based signal toward the near surface station and vice versa. Additionally, the system commands directional antenna elements onboard the station to send and receive the relayed signal making the GEO based content available to the near surface station.

Extrinsic polarization-controlled optical anisotropy in plasmon-black phosphorus coupled system

NASA Astrophysics Data System (ADS)

Liu, Zizhuo; Wells, Spencer A.; Butun, Serkan; Palacios, Edgar; Hersam, Mark C.; Aydin, Koray

2018-07-01

Two-dimensional black phosphorus (BP) has drawn extensive research interest due to its promising anisotropic photonic and electronic properties. Here, we study anisotropic optical absorption and photoresponse of exfoliated BP flakes at visible frequencies. We enhance this intrinsic optical anisotropy in BP flakes by coupling plasmonic rectangular nanopatch arrays that support localized surface plasmon resonances. In particular, by combining extrinsic anisotropic plasmonic nanostructures lithographically aligned with intrinsically anisotropic BP flakes, we demonstrate for the first time a combined anisotropic plasmonic-semiconductor coupling that provides significant control over the polarization-dependent optical properties of the plasmon-BP hybrid material system, enhancing polarization-sensitive responses to a larger degree. This hybrid material system not only unveils the plasmon-enhanced mechanisms in BP, but also provides novel controllable functionalities in optoelectronic device applications involving polarization-sensitive optical and electrical responses.

Extrinsic polarization-controlled optical anisotropy in plasmon-black phosphorus coupled system.

PubMed

Liu, Zizhuo; Wells, Spencer A; Butun, Serkan; Palacios, Edgar; Hersam, Mark C; Aydin, Koray

2018-07-13

Two-dimensional black phosphorus (BP) has drawn extensive research interest due to its promising anisotropic photonic and electronic properties. Here, we study anisotropic optical absorption and photoresponse of exfoliated BP flakes at visible frequencies. We enhance this intrinsic optical anisotropy in BP flakes by coupling plasmonic rectangular nanopatch arrays that support localized surface plasmon resonances. In particular, by combining extrinsic anisotropic plasmonic nanostructures lithographically aligned with intrinsically anisotropic BP flakes, we demonstrate for the first time a combined anisotropic plasmonic-semiconductor coupling that provides significant control over the polarization-dependent optical properties of the plasmon-BP hybrid material system, enhancing polarization-sensitive responses to a larger degree. This hybrid material system not only unveils the plasmon-enhanced mechanisms in BP, but also provides novel controllable functionalities in optoelectronic device applications involving polarization-sensitive optical and electrical responses.

Flight Set 360L002 (STS-27) field joint protection system, volume 7

NASA Technical Reports Server (NTRS)

Hale, Elgie

1989-01-01

This report contains the pre-launch functioning data of the Field Joint Protection System (JPS) used on STS-27. Also included is the post flight condition of the JPS components following the launch and recovery of the two redesigned solid rocket motors (RSRM) boosters. The JPS components are: (1) field joint heaters; (2) field joint sensors; (3) field joint moisture seal; (4) moisture seal Kevlar retaining straps; (5) field joint external insulation; (6) vent valve; (7) power cables; and (8) igniter heater.

A non-imaging polarized terahertz passive system for detecting and identifying concealed explosives

NASA Astrophysics Data System (ADS)

Karam, Mostafa A.; Meyer, Doug

2011-06-01

Existing terahertz THz systems for detecting concealed explosives are not capable of identifying explosive type which leads to higher false alarm rates. Moreover, some of those systems are imaging systems that invade personal privacy, and require more processing and computational resources. Other systems have no polarization preference which makes them incapable of capturing the geometric features of an explosive. In this study a non-imaging polarized THz passive system for detecting and identifying concealed explosives overcoming the forgoing shortcomings is developed. The system employs a polarized passive THz sensor in acquiring emitted data from a scene that may have concealed explosives. The acquired data are decomposed into their natural resonance frequencies, and the number of those frequencies is used as criteria in detecting the explosive presence. If the presence of an explosive is confirmed, a set of physically based retrieval algorithms is used in extracting the explosive dielectric constant/refractive index value from natural resonance frequencies and amplitudes of associated signals. Comparing the refractive index value against a database of refractive indexes of known explosives identifies the explosive type. As an application, a system having a dual polarized radiometer operating within the frequency band of 0.62- 0.82 THz is presented and used in detecting and identifying person borne C-4 explosive concealed under a cotton garment. The system showed higher efficiencies in detecting and identifying the explosive.

Constraint on the primordial gravitational waves from the joint analysis of BICEP2 and Planck HFI 353 GHz dust polarization data

NASA Astrophysics Data System (ADS)

Cheng, Cheng; Huang, Qing-Guo; Wang, Sai

2014-12-01

We make a joint analysis of BICEP2 and recently released Planck HFI 353 GHz dust polarization data, and find that there is no evidence for the primordial gravitational waves and the bound on the tensor-to-scalar ratio becomes r < 0.083 at 95% confidence level in the base ΛCDM + tensor model. Extending to the model with running of scalar spectral index, the bound is a little bit relaxed to r < 0.116 at 95% confidence level. Our results imply that the inflation model with a single monomial potential is marginally disfavored at around 95% confidence level. Especially, the m2phi2/2 inflation model is disfavored at more than 2σ level. However, the Starobinsky inflation model gives a nice fit.

Italian polar data center for capacity building associated with the IHY

NASA Astrophysics Data System (ADS)

Damiani, A.; Bendetti, E.; Storini, M.; Rafanelli, C.

The International Heliophysical Year IHY offers a good opportunity to develop and coordinate studies on the Sun-Earth system by using a large variety of simultaneous data obtained by satellite spacecraft and ground based instruments Among these data we recall the ones coming from solar and interplanetary medium observations auroral neutron monitor geomagnetic field ionospheric meteorological and other atmospheric observatories In this context an Information System for the Italian Research in Antarctica SIRIA has started during 2003 aiming to collect information on the scientific research projects funded by the National Antarctic Research Program PNRA of Italy since its birth 1985 It belongs to the Joint Committee on Antarctic Data Management JCADM of SCAR Scientific Committee on Antarctic Research as the Italian Antarctic Data Center SIRIA being the Italian Polar Database gathers also information on research activities conducted in North Pole regions This Information System can be a relevant resource for capacity building associated with the IHY particularly for people involved in interdisciplinary researches We describe the present status of the Italian Polar Data Center and its potential use

Monstrous Ice Cloud System in Titan's Present South Polar Stratosphere

NASA Astrophysics Data System (ADS)

Anderson, Carrie; Samuelson, Robert; McLain, Jason; Achterberg, Richard; Flasar, F. Michael; Milam, Stefanie

2015-11-01

During southern autumn when sunlight was still available, Cassini's Imaging Science Subsystem discovered a cloud around 300 km near Titan's south pole (West, R. A. et al., AAS/DPS Abstracts, 45, #305.03, 2013); the cloud was later determined by Cassini's Visible and InfraRed Mapping Spectrometer to contain HCN ice (de Kok et al., Nature, 514, pp 65-67, 2014). This cloud has proven to be only the tip of an extensive ice cloud system contained in Titan's south polar stratosphere, as seen through the night-vision goggles of Cassini's Composite InfraRed Spectrometer (CIRS). As the sun sets and the gloom of southern winter approaches, evidence is beginning to accumulate from CIRS far-IR spectra that a massive system of nitrile ice clouds is developing in Titan's south polar stratosphere. Even during the depths of northern winter, nothing like the strength of this southern system was evident in corresponding north polar regions.From the long slant paths that are available from limb-viewing CIRS far-IR spectra, we have the first definitive detection of the ν6 band of cyanoacetylene (HC3N) ice in Titan’s south polar stratosphere. In addition, we also see a strong blend of nitrile ice lattice vibration features around 160 cm-1. From these data we are able to derive ice abundances. The most prominent (and still chemically unidentified) ice emission feature, the Haystack, (at 220 cm-1) is also observed. We establish the vertical distributions of the ice cloud systems associated with both the 160 cm-1 feature and the Haystack. The ultimate aim is to refine the physical and possibly the chemical relationships between the two. Transmittance thin film spectra of nitrile ice mixtures obtained in our Spectroscopy for Planetary ICes Environments (SPICE) laboratory are used to support these analyses.

Sedimentology of polar carbonate systems

NASA Astrophysics Data System (ADS)

Frank, T. D.; James, N. P.

2013-12-01

The key attributes, processes, and products associated with carbonate accumulation and diagenesis at tropical and temperate latitudes are well known. Comparatively little work has concentrated on carbonate deposition at the coldest end of the depositional spectrum, the polar shelves. Such deposits are not abundant, but they have the potential to provide unique insights into paleoceanographic and paleoclimatic conditions in regions of the planet that are arguably the most sensitive to global change. We examined skeletal assemblages, facies, stratigraphy, petrography, geochemistry, and diagenesis of Quaternary deposits from the Ross Sea, Antarctica and Permian counterparts from Gondwana (now eastern Australia). These modern and ancient polar carbonate factories possess several unique characteristics that set them apart from better-known systems of the temperate and tropical latitudes. All production is biogenic and there are no significant calcareous phototrophs. Carbonate communities are not capable of building rigid frameworks, and thus their deposits are prone to winnowing and reworking by waves and bottom currents. The seawater, although frigid, is isothermal, and thus deep-water benthic communities can exist near the surface. Carbonate saturation, which is at or below solubility for both aragonite and high-Mg calcite, plays a key role in determining the dominant mineralogy of benthos as well as the preservation potential of skeletal debris. As many taxa precipitate low-Mg calcite in isotopic equilibrium, deposits have potential to provide geochemical proxy information for use in paleoceanographic and paleoclimatic reconstructions. More than any other type of carbonate system, the slow biogenic carbonate production and accumulation in cold waters is achieved firstly by arresting siliciclastic sedimentation and secondly by increasing nutrient availability. Thus, carbonate deposition may occur during the coldest of times, such as during glacial advance when

Image-Guided Surgical Robotic System for Percutaneous Reduction of Joint Fractures.

PubMed

Dagnino, Giulio; Georgilas, Ioannis; Morad, Samir; Gibbons, Peter; Tarassoli, Payam; Atkins, Roger; Dogramadzi, Sanja

2017-11-01

Complex joint fractures often require an open surgical procedure, which is associated with extensive soft tissue damages and longer hospitalization and rehabilitation time. Percutaneous techniques can potentially mitigate these risks but their application to joint fractures is limited by the current sub-optimal 2D intra-operative imaging (fluoroscopy) and by the high forces involved in the fragment manipulation (due to the presence of soft tissue, e.g., muscles) which might result in fracture malreduction. Integration of robotic assistance and 3D image guidance can potentially overcome these issues. The authors propose an image-guided surgical robotic system for the percutaneous treatment of knee joint fractures, i.e., the robot-assisted fracture surgery (RAFS) system. It allows simultaneous manipulation of two bone fragments, safer robot-bone fixation system, and a traction performing robotic manipulator. This system has led to a novel clinical workflow and has been tested both in laboratory and in clinically relevant cadaveric trials. The RAFS system was tested on 9 cadaver specimens and was able to reduce 7 out of 9 distal femur fractures (T- and Y-shape 33-C1) with acceptable accuracy (≈1 mm, ≈5°), demonstrating its applicability to fix knee joint fractures. This study paved the way to develop novel technologies for percutaneous treatment of complex fractures including hip, ankle, and shoulder, thus representing a step toward minimally-invasive fracture surgeries.

Polarization digital holographic microscopy using low-cost liquid crystal polarization rotators

NASA Astrophysics Data System (ADS)

Dovhaliuk, Rostyslav Yu

2018-02-01

Polarization imaging methods are actively used to study anisotropic objects. A number of methods and systems, such as imaging polarimeters, were proposed to measure the state of polarization of light that passed through the object. Digital holographic and interferometric approaches can be used to quantitatively measure both amplitude and phase of a wavefront. Using polarization modulation optics, the measurement capabilities of such interference-based systems can be extended to measure polarization-dependent parameters, such as phase retardation. Different kinds of polarization rotators can be used to alternate the polarization of a reference beam. Liquid crystals are used in a rapidly increasing number of different optoelectronic devices. Twisted nematic liquid crystals are widely used as amplitude modulators in electronic displays and light valves or shutter glass. Such devices are of particular interest for polarization imaging, as they can be used as polarization rotators, and due to large-scale manufacturing have relatively low cost. A simple Mach-Zehnder polarized holographic setup that uses modified shutter glass as a polarization rotator is demonstrated. The suggested approach is experimentally validated by measuring retardation of quarter-wave film.

The dynamic quiet solar corona: 4 days of joint observing with MDI and EIT

NASA Technical Reports Server (NTRS)

Schrijver, C. J.; Shine, R. A.; Hurlburt, N. E.; Tarbell, T. D.; Lemen, J. R.

1997-01-01

The analysis of a sequence of joint extreme ultraviolet imaging telescope (EIT) Fe XII and Michelson Doppler imager (MDI) magnetogram observations of the quiet sun near disk center is presented. It was found that: all the emerging flux above the threshold of approximately 10(sup 17) Mx is associated with enhanced coronal emissions; loop systems between the polarities in ephemeral regions remain visible up to separations of 10000 up to 30000 km; brightenings between approaching opposite polarity network concentrations form when the concentrations are between 5000 and 25000 km apart, and that faint connections up to 40000 km in length form as sets of concentrations of the same polarity coagulate. The coronal emission over patches of the quiet sun depends on the total flux in connected concentrations, on their distance and on the positions and strengths of neighboring concentrations.

Induced polarization imaging of volcanoes

NASA Astrophysics Data System (ADS)

Revil, Andre; Soueid Ahmed, Abdellahi

2017-04-01

The first part of the presentation is related to the petrophysics of induced polarization of volcanic rocks. We described induced polarization of these rocks using a dynamic Stern layer model describing the polarization of the electrical double layer around the mineral grains. This model shows that the normalized chargeability and quadrature conductivity of volcanic rocks is sensitive to the cation exchange capacity (CEC) of these materials and therefore to their alteration. In the second part pf the presentation, we use a geostatistical inversion framework to image chargeability in 2.5D or in 3D. This new framework is benchmarked using synthetic data and data from various volcanoes (Kilaua, Furnas, Yellowstone). We show that chargeability tomography is very complementary to the now classical electrical resistivity tomography in order to image volcanic structures and to separate the conduction in the bulk pore network from interfacial effects such as surface conductivity. This approach appears to be promising as a first step toward joint inversion with seismic and gravity data.

Field joint protection system rain qualification test report

NASA Technical Reports Server (NTRS)

Cook, M.

1989-01-01

This report documents the procedures, performance, and results obtained from the Field Joint Protection System (FJPS) rain test. This test was performed to validate that the flight configuration FJPS prevents the accumulation of moisture in the redesigned solid rocket motor (RSRM) field joints when subjected to simulated prelaunch natural rain environments. The FJPS test article was exposed to rain simulation for approximately 50 minutes. During the test, water entered through the open upper end of the systems tunnel and was funneled down between the tunnel and case. A sealant void at the moisture seal butt splice allowed this water to flow underneath the FJPS. The most likely cause of voids was improper bondline preparation, particularly on the moisture seal surface. In total, water penetrated underneath approximately 60 percent of the FJPS circumference. Because the test article was substantially different from flight configuration (no systems tunnel closeout), results of this test will not affect current flight motors. Due to the omission of systems tunnel covers and systems tunnel floor plate closeout, the test assembly was not representative of flight hardware and resulted in a gross overtest. It is therefore recommended that the test be declared void. It is also recommended that the test be repeated with a complete closeout of the systems tunnel, sealed systems tunnel ends, and improved adhesive bondline preparation.

Distributed computer system enhances productivity for SRB joint optimization

NASA Technical Reports Server (NTRS)

Rogers, James L., Jr.; Young, Katherine C.; Barthelemy, Jean-Francois M.

1987-01-01

Initial calculations of a redesign of the solid rocket booster joint that failed during the shuttle tragedy showed that the design had a weight penalty associated with it. Optimization techniques were to be applied to determine if there was any way to reduce the weight while keeping the joint opening closed and limiting the stresses. To allow engineers to examine as many alternatives as possible, a system was developed consisting of existing software that coupled structural analysis with optimization which would execute on a network of computer workstations. To increase turnaround, this system took advantage of the parallelism offered by the finite difference technique of computing gradients to allow several workstations to contribute to the solution of the problem simultaneously. The resulting system reduced the amount of time to complete one optimization cycle from two hours to one-half hour with a potential of reducing it to 15 minutes. The current distributed system, which contains numerous extensions, requires one hour turnaround per optimization cycle. This would take four hours for the sequential system.

Double-button Fixation System for Management of Acute Acromioclavicular Joint Dislocation

PubMed Central

Torkaman, Ali; Bagherifard, Abolfazl; Mokhatri, Tahmineh; Haghighi, Mohammad Hossein Shabanpour; Monshizadeh, Siamak; Taraz, Hamid; Hasanvand, Amin

2016-01-01

Background: Surgical treatments for acromioclavicular (AC) joint dislocation present with some complications. The present study was designed to evaluate the double-button fixation system in the management of acute acromioclavicular joint dislocation. Methods: This cross sectional study, done between February 2011 to June 2014, consisted of 28 patients who underwent surgical management by the double-button fixation system for acute AC joint dislocation. Age, sex, injury mechanism, dominant hand, side with injury, length of follow up, time before surgery, shoulder and hand (DASH), constant and visual analogue scale (VAS) scores, and all complications of the cases during the follow up were recorded. Results: The mean age of patients was 33.23±6.7 years. Twenty four patients (85.71%) were male and four (14.28%) were female. The significant differences were observed between pre-operation VAS, constant shoulder scores and post-operation measurements. There were not any significant differences between right and left coracoclavicular, but two cases of heterotrophic ossifications were recorded. The mean follow-up time was 16.17±4.38 months. Conclusion: According to the results, the double-button fixation system for management of acute acromioclavicular joint dislocation has suitable results and minimal damage to the soft tissues surrounding the coracoclavicular ligaments. PMID:26894217

Space nuclear system expansion joints

NASA Technical Reports Server (NTRS)

Whitaker, W. D.; Shimazki, T. T.

1973-01-01

The engineering, design, and fabrication status of the expansion joint unit (EJU) to be employed in the NaK primary coolant piping loop of the 5-kwe Reactor thermoelectric system are described. Four EJU's are needed in the NaK primary coolant piping loop. The four EJU's which will be identical, utilize bellows as the flexing member, are hermetically sealed, and provide double containment. The bellows are of a nested-formed design, and are to be constructed of 1-ply thickness of 0.010-in. Inconel 718. The EJU's provide a minimum piping load margin of safety of +0.22.

Design of an unmanned Martian polar exploration system

NASA Technical Reports Server (NTRS)

Baldwin, Curt; Chitwood, Denny; Demann, Brian; Ducheny, Jordan; Hampton, Richard; Kuhns, Jesse; Mercer, Amy; Newman, Shawn; Patrick, Chris; Polakowski, Tony

1994-01-01

The design of an unmanned Martian polar exploration system is presented. The system elements include subsystems for transportation of material from earth to Mars, study of the Martian north pole, power generation, and communications. Early next century, three Atlas 2AS launch vehicles will be used to insert three Earth-Mars transfer vehicles, or buses, into a low-energy transfer orbit. Capture at Mars will be accomplished by aerobraking into a circular orbit. Each bus contains four landers and a communications satellite. Six of the twelve total landers will be deployed at 60 deg intervals along 80 deg N, and the remaining six landers at 5 deg intervals along 30 deg E from 65 deg N to 90 deg N by a combination of retrorockets and parachutes. The three communications satellites will be deployed at altitudes of 500 km in circular polar orbits that are 120 deg out of phase. These placements maximize the polar coverage of the science and communications subsystems. Each lander contains scientific equipment, two microrovers, power supplies, communications equipment, and a science computer. The lander scientific equipment includes a microweather station, seismometer, thermal probe, x-ray spectrometer, camera, and sounding rockets. One rover, designed for short-range (less than 2 km) excursions from the lander, includes a mass spectrometer for mineral analysis, an auger/borescope system for depth profiling, a deployable thermal probe, and charge coupled device cameras for terrain visualization/navigation. The second rover, designed for longer-range (2-5 km) excursions from the lander, includes radar sounding/mapping equipment, a seismometer, and laser ranging devices. Power for all subsystems is supplied by a combination of solar cells, Ni-H batteries, and radioisotope thermoelectric generators. Communications are sequenced from rovers, sounding rockets, and remote sensors to the lander, then to the satellites, through the Deep Space Network to and from earth.

Plasma Irregularities on the Leading and Trailing Edges of Polar Cap Patches

NASA Astrophysics Data System (ADS)

Lamarche, L. J.; Varney, R. H.; Gillies, R.; Chartier, A.; Mitchell, C. N.

2017-12-01

Plasma irregularities in the polar cap have often been attributed to the gradient drift instability (GDI). Traditional fluid theories of GDI predicts irregularity growth only on the trailing edge of polar patches, where the plasma density gradient is parallel to the plasma drift velocity, however many observations show irregularities also form on the leading edge of patches. We consider decameter-scale irregularities detected by polar-latitude SuperDARN (Super Dual Auroral Radar Network) radars with any relationship between the background density gradients and drift velocity. Global electron density from the Multi-Instrument Data Analysis System (MIDAS), a GPS tomography routine, is used to provide context for where irregularities are observed relative to polar patches and finer-scale background density gradients are found from 3D imaging from both the North and Canada faces of the Resolute Bay Incoherent Scatter Radars (RISR-N and RISR-C) jointly. Shear-based instabilities are considered as mechanisms by which plasma irregularities could form on the leading edge of patches. Theoretical predictions of instability growth from both GDI and shear instabilities are compared with irregularity observations for the October 13, 2016 storm.

Design and research on the two-joint mating system of underwater vehicle

NASA Astrophysics Data System (ADS)

Zhang, Zhong-lin; Wang, Li-quan

2013-03-01

In the 21st century, people have come to the era of ocean science and ocean economy. With the development of ocean science and technology and the thorough research on the ocean, underwater mating technique has been widely used in such fields as sunk ship salvage, deep ocean workstation, submarine lifesaving aid and military affairs. In this paper, researches are made home and abroad on mating technology. Two-joint mating system of underwater vehicle is designed including plane system, three-dimensional assembly system and control system in order to increase the capacity of adapting platform obliquity and adopting rotational skirt scheme. It is clear that the system fits the working space of underwater vehicle passageway and there is no interference phenomenon in assembly design. The finite element model of the system shell and the pressurization of the joint are established. The results of the finite element computing and the pressing test are accordant, and thus it can testify that the shell material meet the need of intension and joint pressurization is reliable. Modeling of the control system is accomplished, and simulation and analysis are made, which can provide directions for the controller design of mating system of underwater vehicles.

Constraint on the primordial gravitational waves from the joint analysis of BICEP2 and Planck HFI 353 GHz dust polarization data

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

Cheng, Cheng; Huang, Qing-Guo; Wang, Sai, E-mail: chcheng@itp.ac.cn, E-mail: huangqg@itp.ac.cn, E-mail: wangsai@itp.ac.cn

2014-12-01

We make a joint analysis of BICEP2 and recently released Planck HFI 353 GHz dust polarization data, and find that there is no evidence for the primordial gravitational waves and the bound on the tensor-to-scalar ratio becomes r < 0.083 at 95% confidence level in the base ΛCDM + tensor model. Extending to the model with running of scalar spectral index, the bound is a little bit relaxed to r < 0.116 at 95% confidence level. Our results imply that the inflation model with a single monomial potential is marginally disfavored at around 95% confidence level. Especially, the m{sup 2}φ{supmore » 2}/2 inflation model is disfavored at more than 2σ level. However, the Starobinsky inflation model gives a nice fit.« less

A head-mounted compressive three-dimensional display system with polarization-dependent focus switching

NASA Astrophysics Data System (ADS)

Lee, Chang-Kun; Moon, Seokil; Lee, Byounghyo; Jeong, Youngmo; Lee, Byoungho

2016-10-01

A head-mounted compressive three-dimensional (3D) display system is proposed by combining polarization beam splitter (PBS), fast switching polarization rotator and micro display with high pixel density. According to the polarization state of the image controlled by polarization rotator, optical path of image in the PBS can be divided into transmitted and reflected components. Since optical paths of each image are spatially separated, it is possible to independently focus both images at different depth positions. Transmitted p-polarized and reflected s-polarized images can be focused by convex lens and mirror, respectively. When the focal lengths of the convex lens and mirror are properly determined, two image planes can be located in intended positions. The geometrical relationship is easily modulated by replacement of the components. The fast switching of polarization realizes the real-time operation of multi-focal image planes with a single display panel. Since it is possible to conserve the device characteristic of single panel, the high image quality, reliability and uniformity can be retained. For generating 3D images, layer images for compressive light field display between two image planes are calculated. Since the display panel with high pixel density is adopted, high quality 3D images are reconstructed. In addition, image degradation by diffraction between physically stacked display panels can be mitigated. Simple optical configuration of the proposed system is implemented and the feasibility of the proposed method is verified through experiments.

Flight set 360T004 (STS-30) field joint protection system, volume 7

NASA Technical Reports Server (NTRS)

Hale, Elgie

1989-01-01

The Redesigned Solid Rocket Motors (RSRM) of the Space Transportation System have three field joints that are protected by the Joint Protection Systems (JPS). The igniter heater was mounted on the igniter flange. This report documents the performance of the JPS and igniter heaters on the pad and the post-flight condition of the JPS components. All observations that were written up as Squawks and/or Problem Reports are also discussed. The primary heaters performed satisfactorily and maintained the field joint temperatures within the required temperature range. A secondary heater failed Dielectric Withstanding Voltage (DWV) test during the joint closeout prior to launch. This heater was not used, however, since the primary heater functioned properly. Post-test inspection revealed that pin A of the heater power cable was shorted to the connector shell. Design changes have been implemented to resolve the heater power cable problem. All field joint assemblies met all of the performance requirements.

Development of High Temperature Dissimilar Joint Technology for Fission Surface Power Systems

NASA Technical Reports Server (NTRS)

Locci, Ivan E.; Bowman, Cheryl L.; Gabb, Timothy P.

2009-01-01

NASA is developing fission surface power (FSP) system technology as a potential option for use on the surface of the moon or Mars. The goal is to design a robust system that takes full advantage of existing materials data bases. One of the key components of the power conversion system is the hot-side Heat Exchanger (HX). One possible design for this heat exchanger requires a joint of the dissimilar metals 316L stainless steel and Inconel 718, which must sustain extended operation at high temperatures. This study compares two joining techniques, brazing and diffusion bonding, in the context of forming the requisite stainless steel to superalloy joint. The microstructures produced by brazing and diffusion bonding, the effect of brazing cycle on the mechanical tensile properties of the alloys, and the strength of several brazed joints will be discussed.

USGS Polar Temperature Logging System, Description and Measurement Uncertainties

USGS Publications Warehouse

Clow, Gary D.

2008-01-01

This paper provides an updated technical description of the USGS Polar Temperature Logging System (PTLS) and a complete assessment of the measurement uncertainties. This measurement system is used to acquire subsurface temperature data for climate-change detection in the polar regions and for reconstructing past climate changes using the 'borehole paleothermometry' inverse method. Specifically designed for polar conditions, the PTLS can measure temperatures as low as -60 degrees Celsius with a sensitivity ranging from 0.02 to 0.19 millikelvin (mK). A modular design allows the PTLS to reach depths as great as 4.5 kilometers with a skid-mounted winch unit or 650 meters with a small helicopter-transportable unit. The standard uncertainty (uT) of the ITS-90 temperature measurements obtained with the current PTLS range from 3.0 mK at -60 degrees Celsius to 3.3 mK at 0 degrees Celsius. Relative temperature measurements used for borehole paleothermometry have a standard uncertainty (urT) whose upper limit ranges from 1.6 mK at -60 degrees Celsius to 2.0 mK at 0 degrees Celsius. The uncertainty of a temperature sensor's depth during a log depends on specific borehole conditions and the temperature near the winch and thus must be treated on a case-by-case basis. However, recent experience indicates that when logging conditions are favorable, the 4.5-kilometer system is capable of producing depths with a standard uncertainty (uZ) on the order of 200-250 parts per million.

Analysis of polyethylene terephthalate PET plastic bottle jointing system using finite element method (FEM)

NASA Astrophysics Data System (ADS)

Zaidi, N. A.; Rosli, Muhamad Farizuan; Effendi, M. S. M.; Abdullah, Mohamad Hariri

2017-09-01

For almost all injection molding applications of Polyethylene Terephthalate (PET) plastic was analyzed the strength, durability and stiffness of properties by using Finite Element Method (FEM) for jointing system of wood furniture. The FEM was utilized for analyzing the PET jointing system for Oak and Pine as wood based material of furniture. The difference pattern design of PET as wood jointing furniture gives the difference value of strength furniture itself. The results show the wood specimen with grooves and eclipse pattern design PET jointing give lower global estimated error is 28.90%, compare to the rectangular and non-grooves wood specimen of global estimated error is 63.21%.

Fiber-FSO/wireless convergent systems based on dual-polarization and one optical sideband transmission schemes

NASA Astrophysics Data System (ADS)

Huang, Xu-Hong; Lu, Hai-Han; Li, Chung-Yi; Wang, Yun-Chieh; Chang, Jen-Chieh; Jheng, Yu-Bo; Tsai, Wen-Shing

2018-06-01

A bidirectional fiber-free-space optical (FSO)/wireless convergent system that uses dual-polarization and one optical sideband transmission schemes for hybrid vestigial sideband (VSB)–four-level pulse amplitude modulation (PAM4)/millimeter-wave signal transmission is proposed and demonstrated. Using a dual-polarization scheme, one optical sideband that is modulated by a 56 Gb s‑1 VSB–PAM4 signal (x-polarization) and another optical sideband that is modulated by a 10 Gbps data stream (y-polarization) are separated and polarized orthogonally. One optical sideband modulated by a 10 Gbps data stream (y-polarization) is delivered to efficaciously suppress the dispersion-induced limitation due to a span of 40 km single-mode fiber (SMF) and the distortion due to the beating among multiple sidebands. The proposed bidirectional fiber-FSO/wireless convergent system is a prominent one for providing broadband integrated services, such as the Internet, telecommunication, and 5G mobile networks.

Theory and analysis of a large field polarization imaging system with obliquely incident light.

PubMed

Lu, Xiaotian; Jin, Weiqi; Li, Li; Wang, Xia; Qiu, Su; Liu, Jing

2018-02-05

Polarization imaging technology provides information about not only the irradiance of a target but also the polarization degree and angle of polarization, which indicates extensive application potential. However, polarization imaging theory is based on paraxial optics. When a beam of obliquely incident light passes an analyser, the direction of light propagation is not perpendicular to the surface of the analyser and the applicability of the traditional paraxial optical polarization imaging theory is challenged. This paper investigates a theoretical model of a polarization imaging system with obliquely incident light and establishes a polarization imaging transmission model with a large field of obliquely incident light. In an imaging experiment with an integrating sphere light source and rotatable polarizer, the polarization imaging transmission model is verified and analysed for two cases of natural light and linearly polarized light incidence. Although the results indicate that the theoretical model is consistent with the experimental results, the theoretical model distinctly differs from the traditional paraxial approximation model. The results prove the accuracy and necessity of the theoretical model and the theoretical guiding significance for theoretical and systematic research of large field polarization imaging.

Polarization-based compensation of astigmatism.

PubMed

Chowdhury, Dola Roy; Bhattacharya, Kallol; Chakraborty, Ajay K; Ghosh, Raja

2004-02-01

One approach to aberration compensation of an imaging system is to introduce a suitable phase mask at the aperture plane of an imaging system. We utilize this principle for the compensation of astigmatism. A suitable polarization mask used on the aperture plane together with a polarizer-retarder combination at the input of the imaging system provides the compensating polarization-induced phase steps at different quadrants of the apertures masked by different polarizers. The aberrant phase can be considerably compensated by the proper choice of a polarization mask and suitable selection of the polarization parameters involved. The results presented here bear out our theoretical expectation.

North Polar Erg

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site]

Our topic for the weeks of April 4 and April 11 is dunes on Mars. We will look at the north polar sand sea and at isolated dune fields at lower latitudes. Sand seas on Earth are often called 'ergs,' an Arabic name for dune field. A sand sea differs from a dune field in two ways: 1) a sand sea has a large regional extent, and 2) the individual dunes are large in size and complex in form.

This VIS image was taken at 81 degrees North latitude during Northern spring. This region of the north polar erg is dominated by a different form of dunes than yesterday's image.

Image information: VIS instrument. Latitude 81.4, Longitude 121.9 East (238.1 West). 19 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Students on Ice: International Polar Year Expeditions

NASA Astrophysics Data System (ADS)

Green, G.

2006-12-01

The Students on Ice program has been introducing and connecting the next generation of Polar researchers and scientists to the Arctic and Antarctic Regions since 1999. To date, approximately 600 international high school and university students have participated on these powerful and award-winning educational expeditions. Traveling through the Antarctic and Arctic on ice-class vessels, the students connect with an international educational team, consisting of Polar scientists, educators, researchers and lecturers, and gain valuable first hand information through a variety of different educational formats. Students participate in lectures, seminars, group discussions, `hands-on' science experiments, and experience once-in-a-lifetime opportunities to view rare wildlife, and to visit remote locations of historic, cultural, and scientific significance. In celebration of the upcoming International Polar Years (IPY), Students on Ice is launching nine unique IPY youth expeditions between 2007 and 2009. Intended for high school students, university students, and interested educators, these expeditions are officially endorsed by the International Polar Year Joint Committee. The goals of the SOI-IPY youth expeditions, include raising awareness and understanding about Polar and environmental issues, development of Polar curriculum and resources, inspiring the next generation of scientists and researchers, and promoting the IPY to millions of youth around through outreach, media and partnership activities.

Evaluation of Asphalt Bridge Deck Joint Systems.

DOT National Transportation Integrated Search

2009-12-01

Asphaltic Plug Joint is an expansion joint that is used for new and rehabilitated bridges. It provides a smooth and watertight surface free of debris; and offers simple, easy and staged construction. Asphaltic plug joint can be repaired segmentally a...

14 CFR 23.693 - Joints.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Systems § 23.693 Joints. Control system joints (in push-pull systems) that are subject to angular motion... factor may be reduced to 2.0 for joints in cable control systems. For ball or roller bearings, the...

Graphing Polar Curves

ERIC Educational Resources Information Center

Lawes, Jonathan F.

2013-01-01

Graphing polar curves typically involves a combination of three traditional techniques, all of which can be time-consuming and tedious. However, an alternative method--graphing the polar function on a rectangular plane--simplifies graphing, increases student understanding of the polar coordinate system, and reinforces graphing techniques learned…

Fully automated system for the quantification of human osteoarthritic knee joint effusion volume using magnetic resonance imaging.

PubMed

Li, Wei; Abram, François; Pelletier, Jean-Pierre; Raynauld, Jean-Pierre; Dorais, Marc; d'Anjou, Marc-André; Martel-Pelletier, Johanne

2010-01-01

Joint effusion is frequently associated with osteoarthritis (OA) flare-up and is an important marker of therapeutic response. This study aimed at developing and validating a fully automated system based on magnetic resonance imaging (MRI) for the quantification of joint effusion volume in knee OA patients. MRI examinations consisted of two axial sequences: a T2-weighted true fast imaging with steady-state precession and a T1-weighted gradient echo. An automated joint effusion volume quantification system using MRI was developed and validated (a) with calibrated phantoms (cylinder and sphere) and effusion from knee OA patients; (b) with assessment by manual quantification; and (c) by direct aspiration. Twenty-five knee OA patients with joint effusion were included in the study. The automated joint effusion volume quantification was developed as a four stage sequencing process: bone segmentation, filtering of unrelated structures, segmentation of joint effusion, and subvoxel volume calculation. Validation experiments revealed excellent coefficients of variation with the calibrated cylinder (1.4%) and sphere (0.8%) phantoms. Comparison of the OA knee joint effusion volume assessed by the developed automated system and by manual quantification was also excellent (r = 0.98; P < 0.0001), as was the comparison with direct aspiration (r = 0.88; P = 0.0008). The newly developed fully automated MRI-based system provided precise quantification of OA knee joint effusion volume with excellent correlation with data from phantoms, a manual system, and joint aspiration. Such an automated system will be instrumental in improving the reproducibility/reliability of the evaluation of this marker in clinical application.

Improved decryption quality and security of a joint transform correlator-based encryption system

NASA Astrophysics Data System (ADS)

Vilardy, Juan M.; Millán, María S.; Pérez-Cabré, Elisabet

2013-02-01

Some image encryption systems based on modified double random phase encoding and joint transform correlator architecture produce low quality decrypted images and are vulnerable to a variety of attacks. In this work, we analyse the algorithm of some reported methods that optically implement the double random phase encryption in a joint transform correlator. We show that it is possible to significantly improve the quality of the decrypted image by introducing a simple nonlinear operation in the encrypted function that contains the joint power spectrum. This nonlinearity also makes the system more resistant to chosen-plaintext attacks. We additionally explore the system resistance against this type of attack when a variety of probability density functions are used to generate the two random phase masks of the encryption-decryption process. Numerical results are presented and discussed.

New generation high performance in situ polarized 3He system for time-of-flight beam at spallation sources.

PubMed

Jiang, C Y; Tong, X; Brown, D R; Glavic, A; Ambaye, H; Goyette, R; Hoffmann, M; Parizzi, A A; Robertson, L; Lauter, V

2017-02-01

Modern spallation neutron sources generate high intensity neutron beams with a broad wavelength band applied to exploring new nano- and meso-scale materials from a few atomic monolayers thick to complicated prototype device-like systems with multiple buried interfaces. The availability of high performance neutron polarizers and analyzers in neutron scattering experiments is vital for understanding magnetism in systems with novel functionalities. We report the development of a new generation of the in situ polarized 3 He neutron polarization analyzer for the Magnetism Reflectometer at the Spallation Neutron Source at Oak Ridge National Laboratory. With a new optical layout and laser system, the 3 He polarization reached and maintained 84% as compared to 76% in the first-generation system. The polarization improvement allows achieving the transmission function varying from 50% to 15% for the polarized neutron beam with the wavelength band of 2-9 Angstroms. This achievement brings a new class of experiments with optimal performance in sensitivity to very small magnetic moments in nano systems and opens up the horizon for its applications.

Suomi NPP Ground System Performance

NASA Astrophysics Data System (ADS)

Grant, K. D.; Bergeron, C.

2013-12-01

The National Oceanic and Atmospheric Administration (NOAA) and National Aeronautics and Space Administration (NASA) are jointly acquiring the next-generation civilian weather and environmental satellite system: the Joint Polar Satellite System (JPSS). JPSS will replace the afternoon orbit component and ground processing system of the current Polar-orbiting Operational Environmental Satellites (POES) managed by NOAA. The JPSS satellites will carry a suite of sensors designed to collect meteorological, oceanographic, climatological and geophysical observations of the Earth. The first satellite in the JPSS constellation, known as the Suomi National Polar-orbiting Partnership (Suomi NPP) satellite, was launched on 28 October 2011, and is currently undergoing product calibration and validation activities. As products reach a beta level of maturity, they are made available to the community through NOAA's Comprehensive Large Array-data Stewardship System (CLASS). CGS's data processing capability processes the satellite data from the Joint Polar Satellite System satellites to provide environmental data products (including Sensor Data Records (SDRs) and Environmental Data Records (EDRs)) to NOAA and Department of Defense (DoD) processing centers operated by the United States government. CGS is currently processing and delivering SDRs and EDRs for Suomi NPP and will continue through the lifetime of the Joint Polar Satellite System programs. Following the launch and sensor activation phase of the Suomi NPP mission, full volume data traffic is now flowing from the satellite through CGS's C3, data processing, and data delivery systems. Ground system performance is critical for this operational system. As part of early system checkout, Raytheon measured all aspects of data acquisition, routing, processing, and delivery to ensure operational performance requirements are met, and will continue to be met throughout the mission. Raytheon developed a tool to measure, categorize, and

Analysis of postmarket complaints database for the iFuse SI Joint Fusion System®: a minimally invasive treatment for degenerative sacroiliitis and sacroiliac joint disruption

PubMed Central

Miller, Larry E; Reckling, W Carlton; Block, Jon E

2013-01-01

Background The sacroiliac joint is a common but under-recognized source of low back and gluteal pain. Patients with degenerative sacroiliitis or sacroiliac joint disruption resistant to nonsurgical treatments may undergo open surgery with sacroiliac joint arthrodesis, although outcomes are mixed and risks are significant. Minimally invasive sacroiliac joint arthrodesis was developed to minimize the risk of iatrogenic injury and to improve patient outcomes compared with open surgery. Methods Between April 2009 and January 2013, 5319 patients were treated with the iFuse SI Joint Fusion System® for conditions including sacroiliac joint disruption and degenerative sacroiliitis. A database was prospectively developed to record all complaints reported to the manufacturer in patients treated with the iFuse device. Complaints were collected through spontaneous reporting mechanisms in support of ongoing mandatory postmarket surveillance efforts. Results Complaints were reported in 204 (3.8%) patients treated with the iFuse system. Pain was the most commonly reported clinical complaint (n = 119, 2.2%), with nerve impingement (n = 48, 0.9%) and recurrent sacroiliac joint pain (n = 43, 0.8%) most frequently cited. All other clinical complaints were rare (≤0.2%). Ninety-six revision surgeries were performed in 94 (1.8%) patients at a median follow-up of four (range 0–30) months. Revisions were typically performed in the early postoperative period for treatment of a symptomatic malpositioned implant (n = 46, 0.9%) or to correct an improperly sized implant in an asymptomatic patient (n = 10, 0.2%). Revisions in the late postoperative period were performed to treat symptom recurrence (n = 34, 0.6%) or for continued pain of undetermined etiology (n = 6, 0.1%). Conclusion Analysis of a postmarket product complaints database demonstrates an overall low risk of complaints with the iFuse SI Joint Fusion System in patients with degenerative sacroiliitis or sacroiliac joint

Analysis of postmarket complaints database for the iFuse SI Joint Fusion System®: a minimally invasive treatment for degenerative sacroiliitis and sacroiliac joint disruption.

PubMed

Miller, Larry E; Reckling, W Carlton; Block, Jon E

2013-01-01

The sacroiliac joint is a common but under-recognized source of low back and gluteal pain. Patients with degenerative sacroiliitis or sacroiliac joint disruption resistant to nonsurgical treatments may undergo open surgery with sacroiliac joint arthrodesis, although outcomes are mixed and risks are significant. Minimally invasive sacroiliac joint arthrodesis was developed to minimize the risk of iatrogenic injury and to improve patient outcomes compared with open surgery. Between April 2009 and January 2013, 5319 patients were treated with the iFuse SI Joint Fusion System® for conditions including sacroiliac joint disruption and degenerative sacroiliitis. A database was prospectively developed to record all complaints reported to the manufacturer in patients treated with the iFuse device. Complaints were collected through spontaneous reporting mechanisms in support of ongoing mandatory postmarket surveillance efforts. Complaints were reported in 204 (3.8%) patients treated with the iFuse system. Pain was the most commonly reported clinical complaint (n = 119, 2.2%), with nerve impingement (n = 48, 0.9%) and recurrent sacroiliac joint pain (n = 43, 0.8%) most frequently cited. All other clinical complaints were rare (≤0.2%). Ninety-six revision surgeries were performed in 94 (1.8%) patients at a median follow-up of four (range 0-30) months. Revisions were typically performed in the early postoperative period for treatment of a symptomatic malpositioned implant (n = 46, 0.9%) or to correct an improperly sized implant in an asymptomatic patient (n = 10, 0.2%). Revisions in the late postoperative period were performed to treat symptom recurrence (n = 34, 0.6%) or for continued pain of undetermined etiology (n = 6, 0.1%). Analysis of a postmarket product complaints database demonstrates an overall low risk of complaints with the iFuse SI Joint Fusion System in patients with degenerative sacroiliitis or sacroiliac joint disruption.

Bidirectional fiber-IVLLC and fiber-wireless convergence system with two orthogonally polarized optical sidebands.

PubMed

Lu, Hai-Han; Wu, Hsiao-Wen; Li, Chung-Yi; Ho, Chun-Ming; Yang, Zih-Yi; Cheng, Ming-Te; Lu, Chang-Kai

2017-05-01

A bidirectional fiber-invisible laser light communication (IVLLC) and fiber-wireless convergence system with two orthogonally polarized optical sidebands for hybrid cable television (CATV)/millimeter-wave (MMW)/baseband (BB) signal transmission is proposed and experimentally demonstrated. Two optical sidebands generated by a 60-GHz MMW signal are orthogonally polarized and separated into different polarizations. These orthogonally polarized optical sidebands are delivered over a 40-km single-mode fiber (SMF) transport to effectually reduce the fiber dispersion induced by a 40-km SMF transmission and the distortion caused by the parallel polarized optical sidebands. To the best of our knowledge, this work is the first to adopt two orthogonally polarized optical sidebands in a bidirectional fiber-IVLLC and fiber-wireless convergence system to reduce fiber dispersion and distortion effectually. Good carrier-to-noise ratio, composite second order, composite triple beat, and bit error rate (BER) are achieved for downlink transmission at a 40-km SMF operation and a 100-m free-space optical (FSO) link/3-m RF wireless transmission. For up-link transmission, good BER performance is acquired over a 40-km SMF transport and a 100-m FSO link. The approach presented in this work signifies the advancements in the convergence of SMF-based backbone and optical/RF wireless-based feeder.

A Review of Natural Joint Systems and Numerical Investigation of Bio-Inspired GFRP-to-Steel Joints

PubMed Central

Avgoulas, Evangelos I.; Sutcliffe, Michael P. F.

2016-01-01

There are a great variety of joint types used in nature which can inspire engineering joints. In order to design such biomimetic joints, it is at first important to understand how biological joints work. A comprehensive literature review, considering natural joints from a mechanical point of view, was undertaken. This was used to develop a taxonomy based on the different methods/functions that nature successfully uses to attach dissimilar tissues. One of the key methods that nature uses to join dissimilar materials is a transitional zone of stiffness at the insertion site. This method was used to propose bio-inspired solutions with a transitional zone of stiffness at the joint site for several glass fibre reinforced plastic (GFRP) to steel adhesively bonded joint configurations. The transition zone was used to reduce the material stiffness mismatch of the joint parts. A numerical finite element model was used to identify the optimum variation in material stiffness that minimises potential failure of the joint. The best bio-inspired joints showed a 118% increase of joint strength compared to the standard joints. PMID:28773688

A Review of Natural Joint Systems and Numerical Investigation of Bio-Inspired GFRP-to-Steel Joints.

PubMed

Avgoulas, Evangelos I; Sutcliffe, Michael P F

2016-07-12

There are a great variety of joint types used in nature which can inspire engineering joints. In order to design such biomimetic joints, it is at first important to understand how biological joints work. A comprehensive literature review, considering natural joints from a mechanical point of view, was undertaken. This was used to develop a taxonomy based on the different methods/functions that nature successfully uses to attach dissimilar tissues. One of the key methods that nature uses to join dissimilar materials is a transitional zone of stiffness at the insertion site. This method was used to propose bio-inspired solutions with a transitional zone of stiffness at the joint site for several glass fibre reinforced plastic (GFRP) to steel adhesively bonded joint configurations. The transition zone was used to reduce the material stiffness mismatch of the joint parts. A numerical finite element model was used to identify the optimum variation in material stiffness that minimises potential failure of the joint. The best bio-inspired joints showed a 118% increase of joint strength compared to the standard joints.

Update of the Polar SWIFT model for polar stratospheric ozone loss (Polar SWIFT version 2)

NASA Astrophysics Data System (ADS)

Wohltmann, Ingo; Lehmann, Ralph; Rex, Markus

2017-07-01

The Polar SWIFT model is a fast scheme for calculating the chemistry of stratospheric ozone depletion in polar winter. It is intended for use in global climate models (GCMs) and Earth system models (ESMs) to enable the simulation of mutual interactions between the ozone layer and climate. To date, climate models often use prescribed ozone fields, since a full stratospheric chemistry scheme is computationally very expensive. Polar SWIFT is based on a set of coupled differential equations, which simulate the polar vortex-averaged mixing ratios of the key species involved in polar ozone depletion on a given vertical level. These species are O3, chemically active chlorine (ClOx), HCl, ClONO2 and HNO3. The only external input parameters that drive the model are the fraction of the polar vortex in sunlight and the fraction of the polar vortex below the temperatures necessary for the formation of polar stratospheric clouds. Here, we present an update of the Polar SWIFT model introducing several improvements over the original model formulation. In particular, the model is now trained on vortex-averaged reaction rates of the ATLAS Chemistry and Transport Model, which enables a detailed look at individual processes and an independent validation of the different parameterizations contained in the differential equations. The training of the original Polar SWIFT model was based on fitting complete model runs to satellite observations and did not allow for this. A revised formulation of the system of differential equations is developed, which closely fits vortex-averaged reaction rates from ATLAS that represent the main chemical processes influencing ozone. In addition, a parameterization for the HNO3 change by denitrification is included. The rates of change of the concentrations of the chemical species of the Polar SWIFT model are purely chemical rates of change in the new version, whereas in the original Polar SWIFT model, they included a transport effect caused by the

Sacroiliac joint involvement in systemic sclerosis.

PubMed

Arslan Tas, Didem; Yıldız, Fatih; Sakallı, Hakan; Kelle, Bayram; Ballı, Tuğsan; Erken, Eren

2015-01-01

One of the major problems for systemic sclerosis (SSc) patients is suggested to be articular involvement. Mostly involved joints in SSc were reported as wrist, carpometacarpal-interphalangeal, foot, knee, hip and shoulder; however, there has been little knowledge on the sacroiliac joint. Our aim was to evaluate sacroiliac joint involvement in SSc. Fifty-seven SSc patients, 54 rheumatoid arthritis patients and 64 healthy subjects were included. Anteroposterior pelvic radiographs were obtained and graded twice by three blinded rheumatologists. One competent radiologist has re-evaluated the X-ray results. The ASAS (Assessment of Spondylo Arthritis International Society) scoring method was applied for grading sacroiliac involvement. Inflammatory back pain was also evaluated. Other clinical and laboratory data were collected as proposed by the European Study Group. In the SSc group sacroiliitis was found in 13 patients (23%) and was significantly different from RA patients (two patients, 4%), P = 0.003; and the healthy control group (one participant, 2%), P < 0.001. The frequency of inflammatory back pain in SSc patients with sacroiliitis (8/13 patients, 62%) was significantly higher in SSc patients without sacroiliitis (4/44 patients, 9%), P < 0.001. The SSc patients with sacroiliitis and with inflammatory back pain (8/57 patients, 14%) were regarded as axial spondyloarthritis overlap. Male gender, diffuse subtype, inflammatory back pain and high C-reactive protein levels (odds ratio: 1.069, 1.059, 1.059 and 3.698, respectively) were found to be the significant risk factors for sacroiliitis. We suggest that, sacroiliitis may be a concern to be considered in SSc practice. © 2014 Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd.

Automated Welding System

NASA Technical Reports Server (NTRS)

Bayless, E. O.; Lawless, K. G.; Kurgan, C.; Nunes, A. C.; Graham, B. F.; Hoffman, D.; Jones, C. S.; Shepard, R.

1993-01-01

Fully automated variable-polarity plasma arc VPPA welding system developed at Marshall Space Flight Center. System eliminates defects caused by human error. Integrates many sensors with mathematical model of the weld and computer-controlled welding equipment. Sensors provide real-time information on geometry of weld bead, location of weld joint, and wire-feed entry. Mathematical model relates geometry of weld to critical parameters of welding process.

Integrin-linked kinase interactions with ELMO2 modulate cell polarity.

PubMed

Ho, Ernest; Irvine, Tames; Vilk, Gregory J A; Lajoie, Gilles; Ravichandran, Kodi S; D'Souza, Sudhir J A; Dagnino, Lina

2009-07-01

Cell polarization is a key prerequisite for directed migration during development, tissue regeneration, and metastasis. Integrin-linked kinase (ILK) is a scaffold protein essential for cell polarization, but very little is known about the precise mechanisms whereby ILK modulates polarization in normal epithelia. Elucidating these mechanisms is essential to understand tissue morphogenesis, transformation, and repair. Here we identify a novel ILK protein complex that includes Engulfment and Cell Motility 2 (ELMO2). We also demonstrate the presence of RhoG in ILK-ELMO2 complexes, and the localization of this multiprotein species specifically to the leading lamellipodia of polarized cells. Significantly, the ability of RhoG to bind ELMO is crucial for ILK induction of cell polarization, and the joint expression of ILK and ELMO2 synergistically promotes the induction of front-rear polarity and haptotactic migration. This places RhoG-ELMO2-ILK complexes in a key position for the development of cell polarity and forward movement. Although ILK is a component of many diverse multiprotein species that may contribute to cell polarization, expression of dominant-negative ELMO2 mutants is sufficient to abolish the ability of ILK to promote cell polarization. Thus, its interaction with ELMO2 and RhoG is essential for the ability of ILK to induce front-rear cell polarity.

The significance of direct sunlight and polarized skylight in the ant's celestial system of navigation.

PubMed

Wehner, Rüdiger; Müller, Martin

2006-08-15

As textbook knowledge has it, bees and ants use polarized skylight as a backup cue whenever the main compass cue, the sun, is obscured by clouds. Here we show, by employing a unique experimental paradigm, that the celestial compass system of desert ants, Cataglyphis, relies predominantly on polarized skylight. If ants experience only parts of the polarization pattern during training but the full pattern in a subsequent test situation, they systematically deviate from their true homeward courses, with the systematics depending on what parts of the skylight patterns have been presented during training. This "signature" of the polarization compass remains unaltered, even if the ants can simultaneously experience the sun, which, if presented alone, enables the ants to select their true homeward courses. Information provided by direct sunlight and polarized skylight is picked up by different parts of the ant's compound eyes and is channeled into two rather separate systems of navigation.

Polar Layers in False Color

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site]

The theme for the weeks of 1/17 and 1/24 is the north polar region of Mars as seen in false color THEMIS images. Ice/frost will typically appear as bright blue in color; dust mantled ice will appear in tones of red/orange.

This image again illustrates the oranger/bluer nature of the polar layers.

Image information: VIS instrument. Latitude 80.6, Longitude 70.2 East (289.8 West). 40 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

The Joint Lessons Learned System and Interoperability

DTIC Science & Technology

1989-06-02

Learned: 1988-1989 As mentioned in the introduction to this chaoter, the Organizacion of the JcinC Chiefs cf Staff .OJCS) ueren significant transformatioi...Organization and Functions Manual . Washington, D.C.: HQDA, Office of the Deputy Chief 0f Staff for Operations and Plans, June 1984. ’..S. Army. Concept...U.S. Department of Defense. Joint Universal Lessons Learned System (JULLS) User’s Manual . Orlando, Florida: University of Central Florida, Institute

Magnetization of a quantum spin system induced by a linear polarized laser

NASA Astrophysics Data System (ADS)

Zvyagin, A. A.

2015-08-01

It is shown that a linear polarized laser can cause magnetization of a spin system with magnetic anisotropy, the distinguished axis of which is perpendicular to the polarization of the laser field. In the dynamical regime the magnetization oscillates around the nonzero value determined by the parameters of the system. Oscillations have the frequency of the laser field, modulated by the lower Rabi-like frequencies. In the steady-state regime, for a large time scale greater than the characteristic relaxation time, the Rabi-like oscillations are damped, and the magnetization oscillates with the frequency of the laser field around the value which is determined by the relaxation rate also. Analytic results are presented for the spin-1/2 chain. The most direct manifestation of such a behavior can be observed in spin-1/2 Ising chain materials if the linear polarization of the laser field is chosen to be perpendicular to the Ising axis.

Fully automated system for the quantification of human osteoarthritic knee joint effusion volume using magnetic resonance imaging

PubMed Central

2010-01-01

Introduction Joint effusion is frequently associated with osteoarthritis (OA) flare-up and is an important marker of therapeutic response. This study aimed at developing and validating a fully automated system based on magnetic resonance imaging (MRI) for the quantification of joint effusion volume in knee OA patients. Methods MRI examinations consisted of two axial sequences: a T2-weighted true fast imaging with steady-state precession and a T1-weighted gradient echo. An automated joint effusion volume quantification system using MRI was developed and validated (a) with calibrated phantoms (cylinder and sphere) and effusion from knee OA patients; (b) with assessment by manual quantification; and (c) by direct aspiration. Twenty-five knee OA patients with joint effusion were included in the study. Results The automated joint effusion volume quantification was developed as a four stage sequencing process: bone segmentation, filtering of unrelated structures, segmentation of joint effusion, and subvoxel volume calculation. Validation experiments revealed excellent coefficients of variation with the calibrated cylinder (1.4%) and sphere (0.8%) phantoms. Comparison of the OA knee joint effusion volume assessed by the developed automated system and by manual quantification was also excellent (r = 0.98; P < 0.0001), as was the comparison with direct aspiration (r = 0.88; P = 0.0008). Conclusions The newly developed fully automated MRI-based system provided precise quantification of OA knee joint effusion volume with excellent correlation with data from phantoms, a manual system, and joint aspiration. Such an automated system will be instrumental in improving the reproducibility/reliability of the evaluation of this marker in clinical application. PMID:20846392

Epi-illumination optical design for fluorescence polarization measurements in flow systems.

PubMed Central

Eisert, W G; Beisker, W

1980-01-01

An epi-illumination design for fluorescence polarization measurements is introduced in flow cytometry with the optical axis orthogonally aligned to the cell stream. Various optical components and designs are discussed with respect to their influence on polarization measurements. Using the epi-configuration, paired measurements with the direction of polarization of the exciting light changed orthogonally are proposed for the compensation of system anisotropies and electronic mismatch. Large aperture corrections are employed for the excitation as well as for the emission pathway. Additional parameters such as fluorescence at 90 degrees, multiangle light scattering, and high precision cell-sizing by internally calibrated time of the flight measurements, as described previously, remain available with the design proposed here. Fluorescent latex microspheres, stained intracellular DNA, and algae have been used to test performance. PMID:7023562

Spectral and Polarization Sensitivity of the Dipteran Visual System

PubMed Central

McCann, Gilbert D.; Arnett, David W.

1972-01-01

Spectral and polarization sensitivity measurements were made at several levels (retina, first and third optic ganglion, cervical connective, behavior) of the dipteran visual nervous system. At all levels, it was possible to reveal contributions from the retinular cell subsystem cells 1 to 6 or the retinular cell subsystem cells 7 and 8 or both. Only retinular cells 1 to 6 were directly studied, and all possessed the same spectral sensitivity characterized by two approximately equal sensitivity peaks at 350 and 480 nm. All units of both the sustaining and on-off variety in the first optic ganglion exhibited the same spectral sensitivity as that of retinular cells 1 to 6. It was possible to demonstrate for motion detection and optomotor responses two different spectral sensitivities depending upon the spatial wavelength of the stimulus. For long spatial wavelengths, the spectral sensitivity agreed with retinular cells 1 to 6; however, the spectral sensitivity at short spatial wavelengths was characterized by a single peak at 465 nm reflecting contributions from the (7, 8) subsystem. Although the two subsystems exhibited different spectral sensitivities, the difference was small and no indication of color discrimination mechanisms was observed. Although all retinular cells 1 to 6 exhibited a preferred polarization plane, sustaining and on-off units did not. Likewise, motion detection and optomotor responses were insensitive to the polarization plane for long spatial wavelength stimuli; however, sensitivity to select polarization planes was observed for short spatial wavelengths. PMID:5027759

Double density dynamics: realizing a joint distribution of a physical system and a parameter system

NASA Astrophysics Data System (ADS)

Fukuda, Ikuo; Moritsugu, Kei

2015-11-01

To perform a variety of types of molecular dynamics simulations, we created a deterministic method termed ‘double density dynamics’ (DDD), which realizes an arbitrary distribution for both physical variables and their associated parameters simultaneously. Specifically, we constructed an ordinary differential equation that has an invariant density relating to a joint distribution of the physical system and the parameter system. A generalized density function leads to a physical system that develops under nonequilibrium environment-describing superstatistics. The joint distribution density of the physical system and the parameter system appears as the Radon-Nikodym derivative of a distribution that is created by a scaled long-time average, generated from the flow of the differential equation under an ergodic assumption. The general mathematical framework is fully discussed to address the theoretical possibility of our method, and a numerical example representing a 1D harmonic oscillator is provided to validate the method being applied to the temperature parameters.

Linear polarization of a group of symbiotic systems

NASA Astrophysics Data System (ADS)

Brandi, E.; García, L. G.; Piirola, V.; Scaltriti, F.; Quiroga, C.

2000-08-01

We report linear polarization measurements of a set of symbiotic stars, made at several epochs during the period 1994-1998. Evidence of intrinsic polarization is looked for from the wavelength dependence of the polarization degree and position angle in UBVRI bands. The results have also been analysed to search for temporal variability of polarization. Several objects have shown a polarization spectrum different from that produced by interstellar dust grains and/or polarimetric variations on time scales as short as several days or months, indicating the presence of polarization component of circumstellar origin. Based on observations taken at Complejo Astronómico El Leoncito (CASLEO), operated under an agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina, the Secretaría de Ciencia y Tecnología de la Nación and the National Universities of La Plata, Córdoba and San Juan.

Conservation of Planar Polarity Pathway Function Across the Animal Kingdom.

PubMed

Hale, Rosalind; Strutt, David

2015-01-01

Planar polarity is a well-studied phenomenon resulting in the directional coordination of cells in the plane of a tissue. In invertebrates and vertebrates, planar polarity is established and maintained by the largely independent core and Fat/Dachsous/Four-jointed (Ft-Ds-Fj) pathways. Loss of function of these pathways can result in a wide range of developmental or cellular defects, including failure of gastrulation and problems with placement and function of cilia. This review discusses the conservation of these pathways across the animal kingdom. The lack of vital core pathway components in basal metazoans suggests that the core planar polarity pathway evolved shortly after, but not necessarily alongside, the emergence of multicellularity.

14 CFR 23.693 - Joints.

Code of Federal Regulations, 2011 CFR

2011-01-01

... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.693 Joints. Control system joints (in push-pull systems) that are subject to angular motion... factor may be reduced to 2.0 for joints in cable control systems. For ball or roller bearings, the...

14 CFR 23.693 - Joints.

Code of Federal Regulations, 2010 CFR

2010-01-01

... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.693 Joints. Control system joints (in push-pull systems) that are subject to angular motion... factor may be reduced to 2.0 for joints in cable control systems. For ball or roller bearings, the...

14 CFR 23.693 - Joints.

Code of Federal Regulations, 2012 CFR

2012-01-01

... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.693 Joints. Control system joints (in push-pull systems) that are subject to angular motion... factor may be reduced to 2.0 for joints in cable control systems. For ball or roller bearings, the...

14 CFR 23.693 - Joints.

Code of Federal Regulations, 2014 CFR

2014-01-01

... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.693 Joints. Control system joints (in push-pull systems) that are subject to angular motion... factor may be reduced to 2.0 for joints in cable control systems. For ball or roller bearings, the...

Analysis of Polarizing Optical Systems for Digital Optical Computing with Symmetric Self Electrooptic Devices

DTIC Science & Technology

1991-03-31

I AD-A232 768 I Annual Report Analysis of Polarizing Optical Systems for Digital Optical Computing with I ’ Symmetric Self Electrooptic Devices I To...TTU AND SuSiIU S. PUNDIN mUMBERS Polarizing Optical Systems for Digital Optical Computing with Symmetric Self Electrooptic Devices AFOSR-89-0542 C...UTION COO$ UNLIMITED 13. ABSTRACT (MAxnum00woUw Two architectural approaches have dominated the field of optical computing . The first appAch uses

Joint Symbol Timing and CFO Estimation for OFDM/OQAM Systems in Multipath Channels

NASA Astrophysics Data System (ADS)

Fusco, Tilde; Petrella, Angelo; Tanda, Mario

2009-12-01

The problem of data-aided synchronization for orthogonal frequency division multiplexing (OFDM) systems based on offset quadrature amplitude modulation (OQAM) in multipath channels is considered. In particular, the joint maximum-likelihood (ML) estimator for carrier-frequency offset (CFO), amplitudes, phases, and delays, exploiting a short known preamble, is derived. The ML estimators for phases and amplitudes are in closed form. Moreover, under the assumption that the CFO is sufficiently small, a closed form approximate ML (AML) CFO estimator is obtained. By exploiting the obtained closed form solutions a cost function whose peaks provide an estimate of the delays is derived. In particular, the symbol timing (i.e., the delay of the first multipath component) is obtained by considering the smallest estimated delay. The performance of the proposed joint AML estimator is assessed via computer simulations and compared with that achieved by the joint AML estimator designed for AWGN channel and that achieved by a previously derived joint estimator for OFDM systems.

Latency features of SafetyNet ground systems architecture for the National Polar-orbiting Operational Environmental Satellite System (NPOESS)

NASA Astrophysics Data System (ADS)

Duda, James L.; Mulligan, Joseph; Valenti, James; Wenkel, Michael

2005-01-01

A key feature of the National Polar-orbiting Operational Environmental Satellite System (NPOESS) is the Northrop Grumman Space Technology patent-pending innovative data routing and retrieval architecture called SafetyNetTM. The SafetyNetTM ground system architecture for the National Polar-orbiting Operational Environmental Satellite System (NPOESS), combined with the Interface Data Processing Segment (IDPS), will together provide low data latency and high data availability to its customers. The NPOESS will cut the time between observation and delivery by a factor of four when compared with today's space-based weather systems, the Defense Meteorological Satellite Program (DMSP) and NOAA's Polar-orbiting Operational Environmental Satellites (POES). SafetyNetTM will be a key element of the NPOESS architecture, delivering near real-time data over commercial telecommunications networks. Scattered around the globe, the 15 unmanned ground receptors are linked by fiber-optic systems to four central data processing centers in the U. S. known as Weather Centrals. The National Environmental Satellite, Data and Information Service; Air Force Weather Agency; Fleet Numerical Meteorology and Oceanography Center, and the Naval Oceanographic Office operate the Centrals. In addition, this ground system architecture will have unused capacity attendant with an infrastructure that can accommodate additional users.

A polarization-division multiplexing SSB-OFDM system with beat interference cancellation receivers

NASA Astrophysics Data System (ADS)

Yang, Peiling; Ma, Jianxin; Zhang, Junyi

2018-06-01

In this paper, we have proposed a polarization-division multiplexing (PDM) single-sideband optical orthogonal frequency division multiplexing (SSB-OOFDM) scheme with signal-signal beat interference cancellation receivers with balanced detection (ICRBD). This system can double channel capacity and improve spectrum efficiency (SE) with the reduced guard band (GB) due to the PDM. Multiple input multiple output (MIMO) technique is used to solve polarization mode dispersion (PMD) associated with channel estimation and equalization. By simulation, we demonstrate the efficacy of the proposed technique for a 2 ×40 Gbit/s 16-QAM SSB-PDM-OOFDM system according to the error vector magnitude (EVM) and the constellation diagrams.

Program of polarization studies and capabilities of accelerating polarized proton and light nuclear beams at the nuclotron of the joint institute for nuclear research

NASA Astrophysics Data System (ADS)

Vokal, S.; Kovalenko, A. D.; Kondratenko, A. M.; Kondratenko, M. A.; Mikhailov, V. A.; Filatov, Yu. N.; Shimanskii, S. S.

2009-01-01

A program of polarization studies is presented; this program can enhance our understanding of the constituents from which the spin of hadrons and lightest nuclei is constructed. Beams of polarized lightest nuclei at Nuclotron are required to complete this program. Calculations of linear resonance strengths at Nuclotron, which may result in depolarization effects, are presented. The application of a new method for conserving particle beam polarization at crossing these resonances at Nuclotron is discussed.

A Rising Tide for Polar Science: Efforts of the U.S. National Committee for the International Polar Year

NASA Astrophysics Data System (ADS)

Albert, M. R.

2003-12-01

The polar regions, fascinating yet distant and cold places, hold the keys to our changing world. While the upcoming IPY is the 50th anniversary of the International Geophysical Year and the 125th anniversary of the first International Polar Year, it also falls at a crucial time in rapid changes in environmental and social systems that may affect all peoples of the Earth. Further warming of the Arctic, changing ecosystems and opening pathways for ocean travel, impact not only the people there but also the shipping, economics, and strategic considerations of distant nations. Yet potential further warming of the Arctic may be understood by clues in the Antarctic ice. How are the polar regions changing, and how swiftly may those changes affect the entire Earth? This is but one question emerging from community discussions of the science of the upcoming IPY. Our emerging ability to investigate previously unexplored areas is increasing our understanding of the wide world we live in, through interdisciplinary studies and tools for connections. Autonomous vehicles, genomics, and remote sensing technologies are just a few of the emerging areas that may provide new tools for investigating previously inaccessible realms. At the same time, tools such as the internet are making the world smaller, enabling instant communications between the peoples of the world. Joint international investigations enhance our ability to understand one another as well as our ability to understand our world and our universe. Rapid communications and international involvement can revolutionize the way we educate young scientists and our future leaders in a complex and changing world. Involving and educating people - young scientists, college students, school children, and the public - will be included as hallmarks of the IPY. The people are here. New tools are emerging. The ideas, or scientific goals, of the IPY are being crafted jointly through broad involvement of the scientific community, through

Lunar true polar wander inferred from polar hydrogen.

PubMed

Siegler, M A; Miller, R S; Keane, J T; Laneuville, M; Paige, D A; Matsuyama, I; Lawrence, D J; Crotts, A; Poston, M J

2016-03-24

The earliest dynamic and thermal history of the Moon is not well understood. The hydrogen content of deposits near the lunar poles may yield insight into this history, because these deposits (which are probably composed of water ice) survive only if they remain in permanent shadow. If the orientation of the Moon has changed, then the locations of the shadowed regions will also have changed. The polar hydrogen deposits have been mapped by orbiting neutron spectrometers, and their observed spatial distribution does not match the expected distribution of water ice inferred from present-day lunar temperatures. This finding is in contrast to the distribution of volatiles observed in similar thermal environments at Mercury's poles. Here we show that polar hydrogen preserves evidence that the spin axis of the Moon has shifted: the hydrogen deposits are antipodal and displaced equally from each pole along opposite longitudes. From the direction and magnitude of the inferred reorientation, and from analysis of the moments of inertia of the Moon, we hypothesize that this change in the spin axis, known as true polar wander, was caused by a low-density thermal anomaly beneath the Procellarum region. Radiogenic heating within this region resulted in the bulk of lunar mare volcanism and altered the density structure of the Moon, changing its moments of inertia. This resulted in true polar wander consistent with the observed remnant polar hydrogen. This thermal anomaly still exists and, in part, controls the current orientation of the Moon. The Procellarum region was most geologically active early in lunar history, which implies that polar wander initiated billions of years ago and that a large portion of the measured polar hydrogen is ancient, recording early delivery of water to the inner Solar System. Our hypothesis provides an explanation for the antipodal distribution of lunar polar hydrogen, and connects polar volatiles to the geologic and geophysical evolution of the Moon

Wearable Vector Electrical Bioimpedance System to Assess Knee Joint Health

PubMed Central

Hersek, Sinan; Töreyin, Hakan; Teague, Caitlin N.; Millard-Stafford, Mindy L.; Jeong, Hyeon-Ki; Bavare, Miheer M.; Wolkoff, Paul; Sawka, Michael N.; Inan, Omer T.

2017-01-01

Objective We designed and validated a portable electrical bioimpedance (EBI) system to quantify knee joint health. Methods Five separate experiments were performed to demonstrate the: (1) ability of the EBI system to assess knee injury and recovery; (2) inter-day variability of knee EBI measurements; (3) sensitivity of the system to small changes in interstitial fluid volume; (4) reducing the error of EBI measurements using acceleration signals; (5) use of the system with dry electrodes integrated to a wearable knee wrap. Results (1) The absolute difference in resistance (R) and reactance (X) from the left to the right knee was able to distinguish injured and healthy knees (p<0.05); the absolute difference in R decreased significantly (p<0.05) in injured subjects following rehabilitation. (2) The average inter-day variability (standard deviation) of the absolute difference in knee R was 2.5Ω, and for X was, 1.2 Ω. (3) Local heating/cooling resulted in a significant decrease/increase in knee R (p<0.01). (4) The proposed subject position detection algorithm achieved 97.4% leave-one subject out cross-validated accuracy and 98.2% precision in detecting when the subject is in the correct position to take measurements. (5) Linear regression between the knee R and X measured using the wet electrodes and the designed wearable knee wrap were highly correlated (r2 = 0.8 and 0.9, respectively). Conclusion This work demonstrates the use of wearable EBI measurements in monitoring knee joint health. Significance The proposed wearable system has the potential for assessing knee joint health outside the clinic/lab and help guide rehabilitation. PMID:28026745

Wearable Vector Electrical Bioimpedance System to Assess Knee Joint Health.

PubMed

Hersek, Sinan; Toreyin, Hakan; Teague, Caitlin N; Millard-Stafford, Mindy L; Jeong, Hyeon-Ki; Bavare, Miheer M; Wolkoff, Paul; Sawka, Michael N; Inan, Omer T

2017-10-01

We designed and validated a portable electrical bioimpedance (EBI) system to quantify knee joint health. Five separate experiments were performed to demonstrate the: 1) ability of the EBI system to assess knee injury and recovery; 2) interday variability of knee EBI measurements; 3) sensitivity of the system to small changes in interstitial fluid volume; 4) reducing the error of EBI measurements using acceleration signals; and 5) use of the system with dry electrodes integrated to a wearable knee wrap. 1) The absolute difference in resistance ( R) and reactance (X) from the left to the right knee was able to distinguish injured and healthy knees (p < 0.05); the absolute difference in R decreased significantly (p < 0.05) in injured subjects following rehabilitation. 2) The average interday variability (standard deviation) of the absolute difference in knee R was 2.5 Ω and for X was 1.2 Ω. 3) Local heating/cooling resulted in a significant decrease/increase in knee R (p < 0.01). 4) The proposed subject position detection algorithm achieved 97.4% leave-one subject out cross-validated accuracy and 98.2% precision in detecting when the subject is in the correct position to take measurements. 5) Linear regression between the knee R and X measured using the wet electrodes and the designed wearable knee wrap were highly correlated ( R 2 = 0.8 and 0.9, respectively). This study demonstrates the use of wearable EBI measurements in monitoring knee joint health. The proposed wearable system has the potential for assessing knee joint health outside the clinic/lab and help guide rehabilitation.

An evaluation of bridge deck joint sealing systems in Virginia.

DOT National Transportation Integrated Search

2003-01-01

The design and fabrication of bridge expansion joint (or movement) systems comprise a rapidly evolving industry. New designs are constantly being presented for trial, often on a piecemeal basis. Occasionally, failures of products occur without suffic...

Luminescent systems based on the isolation of conjugated PI systems and edge charge compensation with polar molecules on a charged nanostructured surface

DOEpatents

Ivanov, Ilia N.; Puretzky, Alexander A.; Zhao, Bin; Geohegan, David B.; Styers-Barnett, David J.; Hu, Hui

2014-07-15

A photoluminescent or electroluminescent system and method of making a non-luminescent nanostructured material into such a luminescent system is presented. The method of preparing the luminescent system, generally, comprises the steps of modifying the surface of a nanostructured material to create isolated regions to act as luminescent centers and to create a charge imbalance on the surface; applying more than one polar molecule to the charged surface of the nanostructured material; and orienting the polar molecules to compensate for the charge imbalance on the surface of the nanostructured material. The compensation of the surface charge imbalance by the polar molecules allows the isolated regions to exhibit luminescence.

New constraints on cosmic polarization rotation from B-mode polarization in the cosmic microwave background

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

Alighieri, Sperello di Serego; Ni, Wei-Tou; Pan, Wei-Ping, E-mail: sperello@arcetri.astro.it, E-mail: weitou@gmail.com, E-mail: d9722518@oz.nthu.edu.tw

2014-09-01

SPTpol, POLARBEAR, and BICEP2 have recently measured the cosmic microwave background (CMB) B-mode polarization in various sky regions of several tens of square degrees and obtained BB power spectra in the multipole range 20-3000, detecting the components due to gravitational lensing and to inflationary gravitational waves. We analyze jointly the results of these three experiments and propose modifications to their analyses of the spectra to include in the model, in addition to the gravitational lensing and the inflationary gravitational wave components, and also the effects induced by the cosmic polarization rotation (CPR), if it exists within current upper limits. Althoughmore » in principle our analysis would also lead to new constraints on CPR, in practice these can only be given on its fluctuations (δα{sup 2}), since constraints on its mean angle are inhibited by the derotation which is applied by current CMB polarization experiments, in order to cope with the insufficient calibration of the polarization angle. The combined data fits from all three experiments (with 29% CPR-SPTpol correlation, depending on the theoretical model) gives the constraint (δα{sup 2}){sup 1/2} < 27.3 mrad (1.°56), with r = 0.194 ± 0.033. These results show that the present data are consistent with no CPR detection and the constraint on CPR fluctuation is about 1.°5. This method of constraining the CPR is new, is complementary to previous tests, which use the radio and optical/UV polarization of radio galaxies and the CMB E-mode polarization, and adds a new constraint for the sky areas observed by SPTpol, POLARBEAR, and BICEP2.« less

Polar Flagellar Motility of the Vibrionaceae

PubMed Central

McCarter, Linda L.

2001-01-01

Polar flagella of Vibrio species can rotate at speeds as high as 100,000 rpm and effectively propel the bacteria in liquid as fast as 60 μm/s. The sodium motive force powers rotation of the filament, which acts as a propeller. The filament is complex, composed of multiple subunits, and sheathed by an extension of the cell outer membrane. The regulatory circuitry controlling expression of the polar flagellar genes of members of the Vibrionaceae is different from the peritrichous system of enteric bacteria or the polar system of Caulobacter crescentus. The scheme of gene control is also pertinent to other members of the gamma purple bacteria, in particular to Pseudomonas species. This review uses the framework of the polar flagellar system of Vibrio parahaemolyticus to provide a synthesis of what is known about polar motility systems of the Vibrionaceae. In addition to its propulsive role, the single polar flagellum of V. parahaemolyticus is believed to act as a tactile sensor controlling surface-induced gene expression. Under conditions that impede rotation of the polar flagellum, an alternate, lateral flagellar motility system is induced that enables movement through viscous environments and over surfaces. Although the dual flagellar systems possess no shared structural components and although distinct type III secretion systems direct the simultaneous placement and assembly of polar and lateral organelles, movement is coordinated by shared chemotaxis machinery. PMID:11528005

Integrin-linked Kinase Interactions with ELMO2 Modulate Cell Polarity

PubMed Central

Ho, Ernest; Irvine, Tames; Vilk, Gregory J.A.; Lajoie, Gilles; Ravichandran, Kodi S.; D'Souza, Sudhir J.A.

2009-01-01

Cell polarization is a key prerequisite for directed migration during development, tissue regeneration, and metastasis. Integrin-linked kinase (ILK) is a scaffold protein essential for cell polarization, but very little is known about the precise mechanisms whereby ILK modulates polarization in normal epithelia. Elucidating these mechanisms is essential to understand tissue morphogenesis, transformation, and repair. Here we identify a novel ILK protein complex that includes Engulfment and Cell Motility 2 (ELMO2). We also demonstrate the presence of RhoG in ILK–ELMO2 complexes, and the localization of this multiprotein species specifically to the leading lamellipodia of polarized cells. Significantly, the ability of RhoG to bind ELMO is crucial for ILK induction of cell polarization, and the joint expression of ILK and ELMO2 synergistically promotes the induction of front-rear polarity and haptotactic migration. This places RhoG–ELMO2–ILK complexes in a key position for the development of cell polarity and forward movement. Although ILK is a component of many diverse multiprotein species that may contribute to cell polarization, expression of dominant-negative ELMO2 mutants is sufficient to abolish the ability of ILK to promote cell polarization. Thus, its interaction with ELMO2 and RhoG is essential for the ability of ILK to induce front-rear cell polarity. PMID:19439446

[The polarization characteristics distribution and correction method of the polarization coupling error in ocean remote sensing system].

PubMed

Gao, Jun; Wang, Shu-Peng; Gu, Xing-Fa; Yu, Tao; Fang, Li

2012-06-01

With the development of the quantitative researches using ocean color remote sensing data sets, study on reducing the uncertainty of the response of the ocean color remote sensors to the polarization characteristics of the target has been attracting more and more attention recently. Taking MODIS as an example, the polarization distribution in the whole field of view was analyzed. For the atmosphere path radiance and the apparent radiance considering the coupling between ocean surface and atmosphere, the polarization distribution has a strong relation with the imaging geometry. Compared to the contribution of the polarization from the rough sea surface, the contribution from the atmosphere is dominated. Based on the polarization characteristics in the field of view, the influence of the polarization coupling error on the quality of the satellite data was studied with the assumption of different polarization sensitivities. It was found that errors due to polarization sensitivity in the field of view are lower than water leaving radiance only when the polarization sensitivity is less than 2%. And in this case it can meet the need of the retrieval of water leaving radiative products. The method of the compensation for the polarization coupling error due to the atmosphere is proposed, which proved to be effective to improve the utilization of satellite data and the accuracy of measured radiance by remote sensor.

On the Statistical Analysis of X-ray Polarization Measurements

NASA Technical Reports Server (NTRS)

Strohmayer, T. E.; Kallman, T. R.

2013-01-01

In many polarimetry applications, including observations in the X-ray band, the measurement of a polarization signal can be reduced to the detection and quantification of a deviation from uniformity of a distribution of measured angles of the form alpha plus beta cosine (exp 2)(phi - phi(sub 0) (0 (is) less than phi is less than pi). We explore the statistics of such polarization measurements using both Monte Carlo simulations as well as analytic calculations based on the appropriate probability distributions. We derive relations for the number of counts required to reach a given detection level (parameterized by beta the "number of sigma's" of the measurement) appropriate for measuring the modulation amplitude alpha by itself (single interesting parameter case) or jointly with the position angle phi (two interesting parameters case). We show that for the former case when the intrinsic amplitude is equal to the well known minimum detectable polarization (MDP) it is, on average, detected at the 3sigma level. For the latter case, when one requires a joint measurement at the same confidence level, then more counts are needed, by a factor of approximately equal to 2.2, than that required to achieve the MDP level. We find that the position angle uncertainty at 1sigma confidence is well described by the relation sigma(sub pi) equals 28.5(degrees) divided by beta.

Endoscopic spectral-domain polarization-sensitive optical coherence tomography system

NASA Astrophysics Data System (ADS)

Wang, Yi; Chen, Xiaodong; Hu, Zhiqiang; Li, Qiao; Yu, Daoyin

2008-02-01

In this paper, we introduced a fiber-based endoscopic Spectral-domain Polarization-sensitive OCT (SD-PS-OCT) experimental scheme for detecting the internal organ disease, which is based on low-coherence interferometer and two spectrometers. The SD-PS-OCT has the advantages of both Spectral-domain OCT (SD-OCT) and Polarization-sensitive OCT (PS-OCT). It is able to get the real-time image of reflectivity and birefringence distribution of tissue at the same time. The usage of SD-PS-OCT in endoscopic diagnosing system provides it the possibility to detect the internal organ disease. Since SD-PS-OCT can image the pathological changes of biological tissue below surface (1-3mm) with high resolution (1-15μm), it is able to help diagnosing early diseases of internal organs, which makes it a biomedical technology with bright future.

The significance of direct sunlight and polarized skylight in the ant’s celestial system of navigation

PubMed Central

Wehner, Rüdiger; Müller, Martin

2006-01-01

As textbook knowledge has it, bees and ants use polarized skylight as a backup cue whenever the main compass cue, the sun, is obscured by clouds. Here we show, by employing a unique experimental paradigm, that the celestial compass system of desert ants, Cataglyphis, relies predominantly on polarized skylight. If ants experience only parts of the polarization pattern during training but the full pattern in a subsequent test situation, they systematically deviate from their true homeward courses, with the systematics depending on what parts of the skylight patterns have been presented during training. This “signature” of the polarization compass remains unaltered, even if the ants can simultaneously experience the sun, which, if presented alone, enables the ants to select their true homeward courses. Information provided by direct sunlight and polarized skylight is picked up by different parts of the ant’s compound eyes and is channeled into two rather separate systems of navigation. PMID:16888039

Planar Cell Polarity Pathway – Coordinating morphogenetic cell behaviors with embryonic polarity

PubMed Central

Gray, Ryan S.; Roszko, Isabelle; Solnica-Krezel, Lilianna

2011-01-01

Planar cell polarization entails establishment of cellular asymmetries within the tissue plane. An evolutionarily conserved Planar Cell Polarity (PCP) signaling system employs intra- and intercellular feedback interactions between its core components, including Frizzled, Van Gogh, Flamingo, Prickle and Dishevelled, to establish their characteristic asymmetric intracellular distributions and coordinate planar polarity of cell populations. By translating global patterning information into asymmetries of cell membranes and intracellular organelles, PCP signaling coordinates morphogenetic behaviors of individual cells and cell populations with the embryonic polarity. In vertebrates, by polarizing cilia in the node/Kupffer’s vesicle, PCP signaling links the anteroposterior to left-right embryonic polarity. PMID:21763613

Calibration of a system to collect visible-light polarization data for classification of geosynchronous satellites

NASA Astrophysics Data System (ADS)

Speicher, Andy; Matin, Mohammad; Tippets, Roger; Chun, Francis

2014-09-01

In order to protect critical military and commercial space assets, the United States Space Surveillance Network must have the ability to positively identify and characterize all space objects. Unfortunately, positive identification and characterization of space objects is a manual and labor intensive process today since even large telescopes cannot provide resolved images of most space objects. The objective of this study was to calibrate a system to exploit the optical signature of unresolved geosynchronous satellite images by collecting polarization data in the visible wavelengths for the purpose of revealing discriminating features. These features may lead to positive identification or classification of each satellite. The system was calibrated with an algorithm and process that takes raw observation data from a two-channel polarimeter and converts it to Stokes parameters S0 and S1. This instrumentation is a new asset for the United States Air Force Academy (USAFA) Department of Physics and consists of one 20-inch Ritchey-Chretien telescope and a dual focal plane system fed with a polarizing beam splitter. This study calibrated the system and collected preliminary polarization data on five geosynchronous satellites to validate performance. Preliminary data revealed that each of the five satellites had a different polarization signature that could potentially lead to identification in future studies.

Effect of joint mechanism on vehicle redirectional capability of water-filled road safety barrier systems.

PubMed

Thiyahuddin, M I; Thambiratnam, D P; Gu, Y T

2014-10-01

Portable water-filled barriers (PWFBs) are roadside appurtenances that prevent vehicles from penetrating into temporary construction zones on roadways. PWFBs are required to satisfy the strict regulations for vehicle re-direction in tests. However, many of the current PWFBs fail to re-direct the vehicle at high speeds due to the inability of the joints to provide appropriate stiffness. The joint mechanism hence plays a crucial role in the performance of a PWFB system at high speed impacts. This paper investigates the desired features of the joint mechanism in a PWFB system that can re-direct vehicles at high speeds, while limiting the lateral displacement to acceptable limits. A rectangular "wall" representative of a 30m long barrier system was modeled and a novel method of joining adjacent road barriers was introduced through appropriate pin-joint connections. The impact response of the barrier "wall" and the vehicle was obtained and the results show that a rotational stiffness of 3000kNm/rad at the joints seems to provide the desired features of the PWFB system to re-direct impacting vehicles and restrict the lateral deflection. These research findings will be useful to safety engineers and road barrier designers in developing a new generation of PWFBs for increased road safety. Copyright © 2014 Elsevier Ltd. All rights reserved.

Strength Variation of Parachute Joints

NASA Technical Reports Server (NTRS)

Mollmann, Catherine

2017-01-01

A parachute joint is defined as a location where a component is sewn or connected to another component. During the design and developmental phase of a parachute system, the joints for each structural component are isolated and tested through a process called seam and joint testing. The objective of seam and joint testing is to determine the degradation on a single component due to interaction with other components; this data is then used when calculating the margin of safety for that component. During the engineering developmental phase of CPAS (Capsule Parachute Assembly System), the parachute system for the NASA Orion Crew Module, testing was completed for every joint of the six subsystems: the four parachutes (main, drogue, pilot, and FBCP [forward bay cover parachute]), the retention release bridle, and the retention panels. The number of joint tests for these subsystems totaled 92, which provides a plethora of data and results for further analysis. In this paper, the data and results of these seam and joint tests are examined to determine the effects, if any, of different operators and sewing machines on the strength of parachute joints. Other variables are also studied to determine their effect on joint strength, such as joint complexity, joint strength magnitude, material type, and material construction. Findings reveal that an optimally-run seam and joint test program could result in an increased understanding of the structure of the parachute; this should lead to a parachute built with optimal components, potentially saving system weight and volume.

Joint involvement in systemic lupus erythematosus: From pathogenesis to clinical assessment.

PubMed

Ceccarelli, Fulvia; Perricone, Carlo; Cipriano, Enrica; Massaro, Laura; Natalucci, Francesco; Capalbo, Giuseppe; Leccese, Ilaria; Bogdanos, Dimitrios; Spinelli, Francesca Romana; Alessandri, Cristiano; Valesini, Guido; Conti, Fabrizio

2017-08-01

In the present review, the different phenotypes, clinimetric and imaging tools able to assess joint involvement in patients affected by Systemic Lupus Erythematosus (SLE) have been described and summarized. Furthermore, the current knowledge about the pathogenic mechanism and the potential biomarkers of this feature is reported. A literature search was done in PubMed, accessed via the National Library of Medicine PubMed interface (http://www.ncbi.nlm.nih.gov/pubmed). Firstly, PubMed was searched using the term "systemic lupus erythematosus" OR "lupus" in combination with (AND) "joint" OR "articular".Secondly, the same PubMed research was combined with other terms, such as "pathogenesis" OR "genetic" OR "antibodies" OR "biomarkers" OR "cytokines" OR "imaging" OR "ultrasonography" OR "magnetic resonance" OR "clinimetry". After a stringent selection, we evaluated in the present review 13 papers concerning clinical phenotypes of SLE joint involvement, 14 concerning clinimetric assessment, 20 concerning imaging, and finally, 28 concerning pathogenesis and biomarkers. Further relevant data were obtained from the reference lists of articles returned using these search terms and from authors own experience and knowledge of the literature. Despite the prevalence and severity of SLE joint involvement, more awareness and a deeper evaluation of the clinical heterogeneity of this manifestation are mandatory. Moreover, longitudinal studies are needed to assess the progression of this manifestation and to provide standard definitions and examination/recording protocols. Copyright © 2017 Elsevier Inc. All rights reserved.

Modification of the Grood and Suntay Joint Coordinate System equations for knee joint flexion.

PubMed

Dabirrahmani, Danè; Hogg, Michael

2017-01-01

Since its introduction, the Grood and Suntay Joint Coordinate System (JCS) has been embraced by the International Society of Biomechanics (ISB) and been widely used for biomechanical reporting. There is, however, a limitation in its ability to provide correct flexion values over a wide range of clinically relevant flexion angles. This technical note addresses the limitation of the JCS equations and introduces a new set of equations to overcome this problem. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

Static analysis of large-scale multibody system using joint coordinates and spatial algebra operator.

PubMed

Omar, Mohamed A

2014-01-01

Initial transient oscillations inhibited in the dynamic simulations responses of multibody systems can lead to inaccurate results, unrealistic load prediction, or simulation failure. These transients could result from incompatible initial conditions, initial constraints violation, and inadequate kinematic assembly. Performing static equilibrium analysis before the dynamic simulation can eliminate these transients and lead to stable simulation. Most exiting multibody formulations determine the static equilibrium position by minimizing the system potential energy. This paper presents a new general purpose approach for solving the static equilibrium in large-scale articulated multibody. The proposed approach introduces an energy drainage mechanism based on Baumgarte constraint stabilization approach to determine the static equilibrium position. The spatial algebra operator is used to express the kinematic and dynamic equations of the closed-loop multibody system. The proposed multibody system formulation utilizes the joint coordinates and modal elastic coordinates as the system generalized coordinates. The recursive nonlinear equations of motion are formulated using the Cartesian coordinates and the joint coordinates to form an augmented set of differential algebraic equations. Then system connectivity matrix is derived from the system topological relations and used to project the Cartesian quantities into the joint subspace leading to minimum set of differential equations.

Welding technology transfer task/laser based weld joint tracking system for compressor girth welds

NASA Technical Reports Server (NTRS)

Looney, Alan

1991-01-01

Sensors to control and monitor welding operations are currently being developed at Marshall Space Flight Center. The laser based weld bead profiler/torch rotation sensor was modified to provide a weld joint tracking system for compressor girth welds. The tracking system features a precision laser based vision sensor, automated two-axis machine motion, and an industrial PC controller. The system benefits are elimination of weld repairs caused by joint tracking errors which reduces manufacturing costs and increases production output, simplification of tooling, and free costly manufacturing floor space.

An X-Ray Survey for Polar CAP Qpos in AM Herculis Systems

NASA Astrophysics Data System (ADS)

Wood, Kent

Five AM Herculis binary systems show an optical QPO that is known to be associated with magentically channeled polar cap accretion. Hard X-ray QPOs are predicted by the time-depndent hydrodynamic models. We propose to search selected AM Her systems for polar cap X-ray QPOs using the XTE PCA. Because of its large collecting area, the PCA is the only instrument that can do this job. No other accreting objects provide comparable high-quality observational diagnostics on the accretion flow. The detailed understanding of flow geometry, shock heating, ion-electron energy exchange, accretion column structure, and emission and radiative transfer mechanisms that go to make up the picture of AM Her accretion needs to be tested against X-ray timing information.

North Polar Water Ice by Weight

NASA Technical Reports Server (NTRS)

2003-01-01

December 8, 2003

This map shows the percent of water by weight in near-surface materials of Mars' north polar region. It is derived from the gamma ray spectrometer component of the gamma ray spectrometer suite of instruments on NASA's Mars Odyssey spacecraft.

Significant concentrations of water (greater than 20 percent) are poleward of 55 degrees north latitude. The highest concentration, greater than 50 percent, is between 75 degrees north and the pole. Another area with a high concentration of water by weight is in the north polar plains between longitudes minus 105 degrees and minus 140 degrees, and between latitudes 60 degrees and 75 degrees.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the 2001 Mars Odyssey mission for the NASA Office of Space Science in Washington. Investigators at Arizona State University in Tempe, the University of Arizona in Tucson and NASA's Johnson Space Center, Houston, operate the science instruments. The gamma-ray spectrometer was provided by the University of Arizona in collaboration with the Russian Aviation and Space Agency, which provided the high-energy neutron detector, and the Los Alamos National Laboratories, New Mexico, which provided the neutron spectrometer. Lockheed Martin Space Systems, Denver, is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL.

Polar Wind Measurements with TIDE/PSI and HYDRA on the Polar Spacecraft

NASA Technical Reports Server (NTRS)

Su, Y. J.; Horwitz, J. L.; Moore, Thomas E.; Giles, Barbara L.; Chandler, Michael O.; Craven, Paul D.; Chang, S.-W.; Scudder, J.

1998-01-01

The Thermal Ion Dynamics Experiment (TIDE) on the POLAR spacecraft has allowed sampling of the three-dimensional ion distributions with excellent energy, angular, and mass resolution. The companion Plasma Source Instrument, when operated, allows sufficient diminution of the electric potential to observe the polar wind at very high altitudes. In this presentation, we will describe the results of polar wind characteristics H+, He+, and 0+ as observed by TIDE at 5000 km and 8 RE altitudes. The relationship of the polar wind parameters with the solar zenith angle and with the day-night distance in the Solar Magnetic coordinate system will also be presented. We will compare these measurements with recent simulations of the photoelectron-driven polar wind using a couple fluid-semikinetic model. In addition, we will compare these polar wind observations with low-energy electrons sampled by the HYDRA experiment on POLAR to examine possible effects of the polar rain and photoelectrons and hopefully explain the large ion outflow velocity variations at POLAR apogee.

North Polar Erg

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site]

Our topic for the weeks of April 4 and April 11 is dunes on Mars. We will look at the north polar sand sea and at isolated dune fields at lower latitudes. Sand seas on Earth are often called 'ergs,' an Arabic name for dune field. A sand sea differs from a dune field in two ways: 1) a sand sea has a large regional extent, and 2) the individual dunes are large in size and complex in form.

This VIS image was taken at 82 degrees North latitude during Northern spring. As with yesterday's image, the dunes are still partially frost covered. This region is part of the north polar erg (sand sea), note the complexity and regional coverage of the dunes.

Image information: VIS instrument. Latitude 81.2, Longitude 118.2 East (241.8 West). 19 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

In situ polarized 3He system for the Magnetism Reflectometer at the Spallation Neutron Source.

PubMed

Tong, X; Jiang, C Y; Lauter, V; Ambaye, H; Brown, D; Crow, L; Gentile, T R; Goyette, R; Lee, W T; Parizzi, A; Robertson, J L

2012-07-01

We report on the in situ polarized (3)He neutron polarization analyzer developed for the time-of-flight Magnetism Reflectometer at the Spallation Neutron Source at Oak Ridge National Laboratory. Using the spin exchange optical pumping method, we achieved a (3)He polarization of 76% ± 1% and maintained it for the entire three-day duration of the test experiment. Based on transmission measurements with unpolarized neutrons, we show that the average analyzing efficiency of the (3)He system is 98% for the neutron wavelength band of 2-5 Å. Using a highly polarized incident neutron beam produced by a supermirror bender polarizer, we obtained a flipping ratio of >100 with a transmission of 25% for polarized neutrons, averaged over the wavelength band of 2-5 Å. After the cell was depolarized for transmission measurements, it was reproducibly polarized and this performance was maintained for three weeks. A high quality polarization analysis experiment was performed on a reference sample of Fe/Cr multilayer with strong spin-flip off-specular scattering. Using a combination of the position sensitive detector, time-of-flight method, and the excellent parameters of the (3)He cell, the polarization analysis of the two-dimensional maps of reflected, refracted, and off-specular scattered intensity above and below the horizon were obtained, simultaneously.

A new measurement of electron transverse polarization in polarized nuclear β-decay

NASA Astrophysics Data System (ADS)

Kawamura, H.; Akiyama, T.; Hata, M.; Hirayama, Y.; Ikeda, M.; Ikeda, Y.; Ishii, T.; Kameda, D.; Mitsuoka, S.; Miyatake, H.; Nagae, D.; Nakaya, Y.; Ninomiya, K.; Nitta, M.; Ogawa, N.; Onishi, J.; Seitaibashi, E.; Tanaka, S.; Tanuma, R.; Totsuka, Y.; Toyoda, T.; Watanabe, Y. X.; Murata, J.

2017-03-01

The Mott polarimetry for T-violation (MTV) experiment tests time-reversal symmetry in polarized nuclear β-decay by measuring an electron’s transverse polarization as a form of angular asymmetry in Mott scattering using a thin metal foil. A Mott scattering analyzer system developed using a tracking detector to measure scattering angles offers better event selectivity than conventional counter experiments. In this paper, we describe a pilot experiment conducted at KEK-TRIAC using a prototype system with a polarized 8Li beam. The experiment confirmed the sound performance of our Mott analyzer system to measure T-violating triple correlation (R correlation), and therefore recommends its use in higher-precision experiments at the TRIUMF-ISAC.

Wide-field imaging of birefringent synovial fluid crystals using lens-free polarized microscopy for gout diagnosis

NASA Astrophysics Data System (ADS)

Zhang, Yibo; Lee, Seung Yoon Celine; Zhang, Yun; Furst, Daniel; Fitzgerald, John; Ozcan, Aydogan

2016-06-01

Gout is a form of crystal arthropathy where monosodium urate (MSU) crystals deposit and elicit inflammation in a joint. Diagnosis of gout relies on identification of MSU crystals under a compensated polarized light microscope (CPLM) in synovial fluid aspirated from the patient’s joint. The detection of MSU crystals by optical microscopy is enhanced by their birefringent properties. However, CPLM partially suffers from the high-cost and bulkiness of conventional lens-based microscopy, and its relatively small field-of-view (FOV) limits the efficiency and accuracy of gout diagnosis. Here we present a lens-free polarized microscope which adopts a novel differential and angle-mismatched polarizing optical design achieving wide-field and high-resolution holographic imaging of birefringent objects with a color contrast similar to that of a standard CPLM. The performance of this computational polarization microscope is validated by imaging MSU crystals made from a gout patient’s tophus and steroid crystals used as negative control. This lens-free polarized microscope, with its wide FOV (>20 mm2), cost-effectiveness and field-portability, can significantly improve the efficiency and accuracy of gout diagnosis, reduce costs, and can be deployed even at the point-of-care and in resource-limited clinical settings.

Wide-field imaging of birefringent synovial fluid crystals using lens-free polarized microscopy for gout diagnosis

PubMed Central

Zhang, Yibo; Lee, Seung Yoon Celine; Zhang, Yun; Furst, Daniel; Fitzgerald, John; Ozcan, Aydogan

2016-01-01

Gout is a form of crystal arthropathy where monosodium urate (MSU) crystals deposit and elicit inflammation in a joint. Diagnosis of gout relies on identification of MSU crystals under a compensated polarized light microscope (CPLM) in synovial fluid aspirated from the patient’s joint. The detection of MSU crystals by optical microscopy is enhanced by their birefringent properties. However, CPLM partially suffers from the high-cost and bulkiness of conventional lens-based microscopy, and its relatively small field-of-view (FOV) limits the efficiency and accuracy of gout diagnosis. Here we present a lens-free polarized microscope which adopts a novel differential and angle-mismatched polarizing optical design achieving wide-field and high-resolution holographic imaging of birefringent objects with a color contrast similar to that of a standard CPLM. The performance of this computational polarization microscope is validated by imaging MSU crystals made from a gout patient’s tophus and steroid crystals used as negative control. This lens-free polarized microscope, with its wide FOV (>20 mm2), cost-effectiveness and field-portability, can significantly improve the efficiency and accuracy of gout diagnosis, reduce costs, and can be deployed even at the point-of-care and in resource-limited clinical settings. PMID:27356625

Compact rf polarizer and its application to pulse compression systems

DOE PAGES

Franzi, Matthew; Wang, Juwen; Dolgashev, Valery; ...

2016-06-01

We present a novel method of reducing the footprint and increasing the efficiency of the modern multi-MW rf pulse compressor. This system utilizes a high power rf polarizer to couple two circular waveguide modes in quadrature to a single resonant cavity in order to replicate the response of a traditional two cavity configuration using a 4-port hybrid. The 11.424 GHz, high-Q, spherical cavity has a 5.875 cm radius and is fed by the circularly polarized signal to simultaneously excite the degenerate TE 114 modes. The overcoupled spherical cavity has a Q 0 of 9.4×10 4 and coupling factor (β) ofmore » 7.69 thus providing a loaded quality factor Q L of 1.06×10 4 with a fill time of 150 ns. Cold tests of the polarizer demonstrated good agreement with the numerical design, showing transmission of -0.05 dB and reflection back to the input rectangular WR 90 waveguide less than -40 dB over a 100 MHz bandwidth. This novel rf pulse compressor was tested at SLAC using XL-4 Klystron that provided rf power up to 32 MW and generated peak output power of 205 MW and an average of 135 MW over the discharged signal. A general network analysis of the polarizer is discussed as well as the design and high power test of the rf pulse compressor.« less

Self-organization of the climate system: Synchronized polar and oceanic teleconnections

NASA Astrophysics Data System (ADS)

Reischmann, Elizabeth Piccard

Synchronization is a widespread phenomenon in nonlinear, physical systems. It describes the phenomena of two or more weakly interacting, nonlinear oscillators adjust their natural frequencies until they come into phase and frequency lock. This behavior has been observed in biological, chemical and electronic systems, including neurons, fireflies, and computers, but has not been widely studied in climate. This thesis presents a study of several major examples of synchronized climatic systems, starting with ice age timings seemingly caused by the global climate's gradual synchronization to the Earth's 413kyr orbital eccentricity band, which may be responsible for the shift of ice age timings and amplitudes at the Mid-Pleistocene transition. The focus of the thesis, however, is centered the second major example of stable synchronization in the climate system: the continuous, 90 degree phase relationship of the polar climate signals for the entirety of the available ice record. The existence of a relationship between polar climates has been widely observed since ice core proxies became available in both Greenland and Antarctica. However, my work focuses on refining this phase relationship, utilizing it's linear nature to apply deconvolution and establish an energy transfer function. This transfer function shows a distinctly singular frequency, suggesting that climate signal is predominately communicated north to south with a period of 1.6kyrs. This narrows down possible mechanisms of polar connection dramatically, and is further investigated via a collection of intermediate proxy datasets and a set of more contemporary, synchronized, sea surface temperature dipoles. While the former fails to show any strong indication of the nature of the polar signal due in part to the overwhelming uncertainties present on the centennial and millennial scales, the latter demonstrates a large set of synchronized climate oscillations exist, communicate in a variety of networks, and have

The National Polar-orbiting Operational Environmental Satellite System

NASA Astrophysics Data System (ADS)

Hoffman, C. W.; Mango, S.; Schneider, S.; Duda, J.; Haas, J.; Bloom, H.

2005-12-01

Over the last decade, the tri-agency Integrated Program Office (IPO), comprised of the National Oceanic and Atmospheric Administration (NOAA), the Department of Defense (DoD), and the National Aeronautics and Space Administration (NASA), has been managing the development of the National Polar-orbiting Operational Environmental Satellite System (NPOESS). Once operational later this decade, NPOESS will replace NOAA's Polar-orbiting Operational Environmental Satellites (POES) and DoD's Defense Meteorological Satellite Program (DMSP) systems. The IPO, through its Acquisition and Operations contractor, Northrop Grumman, will launch NPOESS spacecraft into three orbital planes to provide a single, national system capable of satisfying both civil and national security requirements for space-based, remotely sensed environmental data. With the development of NPOESS, we are evolving the existing 'weather' satellites into integrated environmental observing systems by expanding our capabilities to observe, assess, and predict the total Earth system - ocean, atmosphere, land, and the space environment. NPOESS will transform today's short-term, space-based ocean research missions into a sustained, operational ocean remote sensing observation program. Ocean measurements comprise one-fourth of the 55 user-validated requirements for geophysical measurements that will be made by NPOESS sensors. In 1997, the IPO initiated a robust sensor risk reduction effort for early development of the critical sensor suites and algorithms necessary to support NPOESS. In 2001, preliminary design efforts were completed for the last of five critical imaging/sounding instruments for NPOESS. Ocean requirements have directly and substantially 'driven' the design of three NPOESS sensors: the Visible/Infrared Imager Radiometer Suite (VIIRS); the Conical-scanning Microwave Imager/Sounder (CMIS); and the Altimeter. With these instruments, NPOESS will deliver higher resolution (spatial and temporal) and more

Double ionization of neon in elliptically polarized femtosecond laser fields

NASA Astrophysics Data System (ADS)

Kang, HuiPeng; Henrichs, Kevin; Wang, YanLan; Hao, XiaoLei; Eckart, Sebastian; Kunitski, Maksim; Schöffler, Markus; Jahnke, Till; Liu, XiaoJun; Dörner, Reinhard

2018-06-01

We present a joint experimental and theoretical investigation of the correlated electron momentum spectra from strong-field double ionization of neon induced by elliptically polarized laser pulses. A significant asymmetry of the electron momentum distributions along the major polarization axis is reported. This asymmetry depends sensitively on the laser ellipticity. Using a three-dimensional semiclassical model, we attribute this asymmetry pattern to the ellipticity-dependent probability distributions of recollision time. Our work demonstrates that, by simply varying the ellipticity, the correlated electron emission can be two-dimensionally controlled and the recolliding electron trajectories can be steered on a subcycle time scale.

Full-subcarriers Polar-OFDM for optical spectrum-efficient transmission exploiting Polarization Multiplexing

NASA Astrophysics Data System (ADS)

Guo, Lei; Liu, Yejun; Zhou, Yufang; Wei, Xuetao; Liu, Yuying

2018-07-01

The exponential growth of the demand for broadband services has imposed great challenges on the design of spectrum-efficient optical transmission system in Passive Optical Network (PON). Recently, an innovative Orthogonal Frequency Division Multiplexing (OFDM) scheme, called Polar-OFDM (P-OFDM), has emerged as a promising solution to boost the spectral efficiency of optical transmission in PON. However, the traditional P-OFDM does not yet perform best in spectral efficiency as it only uses half of the total subcarriers. In this paper, we verify a promising complementation between Polarization Multiplexing (POLMUX) and P-OFDM aiming at higher spectral efficiency. We then propose the full-subcarriers P-OFDM by loading data on the even-indexed subcarriers of X polarization and the odd-indexed subcarriers of Y polarization, respectively. Thus, all of the subcarriers will be utilized for effective data transmission, which can double the spectral efficiency. More importantly, because the subcarriers are interlaced on different polarizations, the cross-polarization interference can be significantly mitigated, which enables the independent channel estimation and equalization at the receiver to recover the data carried on each polarization. Our evaluation results demonstrate that the proposed system realizes the double spectral efficiency of the traditional P-OFDM with reasonable Bit Error Rate (BER) performance loss.

Implementing and testing a fiber-optic polarization-based intrusion detection system

NASA Astrophysics Data System (ADS)

Hajj, Rasha El; MacDonald, Gregory; Verma, Pramode; Huck, Robert

2015-09-01

We describe a layer-1-based intrusion detection system for fiber-optic-based networks. Layer-1-based intrusion detection represents a significant elevation in security as it prohibits an adversary from obtaining information in the first place (no cryptanalysis is possible). We describe the experimental setup of the intrusion detection system, which is based on monitoring the behavior of certain attributes of light both in unperturbed and perturbed optical fiber links. The system was tested with optical fiber links of various lengths and types, under different environmental conditions, and under changes in fiber geometry similar to what is experienced during tapping activity. Comparison of the results for perturbed and unperturbed links has shown that the state of polarization is more sensitive to intrusion activity than the degree of polarization or power of the received light. The testing was conducted in a simulated telecommunication network environment that included both underground and aerial links. The links were monitored for intrusion activity. Attempts to tap the link were easily detected with no apparent degradation in the visual quality of the real-time surveillance video.

Investigation of laser polarized xenon magnetic resonance

NASA Technical Reports Server (NTRS)

Walsworth, Ronald L.

1998-01-01

Ground-based investigations of a new biomedical diagnostic technology: nuclear magnetic resonance of laser polarized noble gas are addressed. The specific research tasks discussed are: (1) Development of a large-scale noble gas polarization system; (2) biomedical investigations using laser polarized noble gas in conventional (high magnetic field) NMR systems; and (3) the development and application of a low magnetic field system for laser polarized noble gas NMR.

An intelligent system with EMG-based joint angle estimation for telemanipulation.

PubMed

Suryanarayanan, S; Reddy, N P; Gupta, V

1996-01-01

Bio-control of telemanipulators is being researched as an alternate control strategy. This study investigates the use of surface EMG from the biceps to predict joint angle during flexion of the arm that can be used to control an anthropomorphic telemanipulator. An intelligent system based on neural networks and fuzzy logic has been developed to use the processed surface EMG signal and predict the joint angle. The system has been tested on various angles of flexion-extension of the arm and at several speeds of flexion-extension. Preliminary results show the RMS error between the predicted angle and the actual angle to be less than 3% during training and less than 15% during testing. The technique of direct bio-control using EMG has the potential as an interface for telemanipulation applications.

Polarized millijoule fiber laser system with high beam quality and pulse shaping ability

NASA Astrophysics Data System (ADS)

Zhang, Rui; Tian, Xiaocheng; Xu, Dangpeng; Zhou, Dandan; Zong, Zhaoyu; Li, Hongxun; Fan, Mengqiu; Huang, Zhihua; Zhu, Na; Su, Jingqin; Zhu, Qihua; Jing, Feng

2017-05-01

The coherent amplification network (CAN) aims at developing a laser system based on the coherent combination of multiple laser beams, which are produced through a network of high beam quality optical fiber amplifiers. The scalability of the CAN laser facilitates the development of many novel applications, such as fiber-based acceleration, orbital debris removal and inertial confinement fusion energy. According to the requirements of CAN and the front end of high-power laser facilities, a millijoule polarized fiber laser system was studied in this paper. Using polarization maintaining Ytterbium-fiber laser system as the seed, and 10-μm core Yb-doped fiber amplifier as the first power amplifier and 40-μm core polarizing (PZ) photonic crystal fiber (PCF) as the second power amplifier, the all-fiber laser system outputs 1.06-mJ energy at 10 ns and diffraction limited mode quality. Using 85-μm rod-type PCF as the third power amplifiers, 2.5-mJ energy at 10-ns pulse width was obtained with better than 500:1 peak-to-foot pulse shaping ability and fundamental mode beam quality. The energy fluctuation of the system is 1.3% rms with 1-mJ output in one hour. When using phase-modulated pulse as the seed, the frequency modulation to amplitude modulation (FM-to-AM) conversion ratio of the system is better than 5%. This fiber laser system has the advantages of high beam quality, high beam shaping ability, good stability, small volume and free of maintenance, which can be used in many applications.

Final Environmental Assessment: Solar Panel Systems at Joint Base McGuire-Dix-Lakehurst New Jersey

DTIC Science & Technology

2012-03-01

FINAL ENVIRONMENTAL ASSESSMENT Solar Panel Systems at Joint Base McGuire-Dix-Lakehurst, New Jersey MARCH 2012...Final Environmental Assessment : Solar Panel Systems at Joint Base McGuire-Dix-Lakehurst New Jersey 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Purpose Finding of No Significant Impact (FONSI) Environmental Assessment (EA

Airborne antenna polarization study for the microwave landing system

NASA Technical Reports Server (NTRS)

Gilreath, M. C.

1976-01-01

The feasibility of the microwave landing system (MLS) airborne antenna pattern coverage requirements are investigated for a large commercial aircraft using a single omnidirectional antenna. Omnidirectional antennas having vertical and horizontal polarizations were evaluated at several different station locations on a one-eleventh scale model Boeing 737 aircraft. The results obtained during this experimental program are presented which include principal plane antenna patterns and complete volumetric coverage plots.

Microwave Polarized Signatures Generated within Cloud Systems: SSM/I Observations Interpreted with Radiative Transfer Simulations

NASA Technical Reports Server (NTRS)

Prigent, Catherine; Pardo, Juan R.; Mishchenko, Michael I.; Rossow, Willaim B.; Hansen, James E. (Technical Monitor)

2001-01-01

Special Sensor Microwave /Imager (SSM/I) observations in cloud systems are studied over the tropics. Over optically thick cloud systems, presence of polarized signatures at 37 and 85 GHz is evidenced and analyzed with the help of cloud top temperature and optical thickness extracted from visible and IR satellite observations. Scattering signatures at 85 GHz (TbV(85) less than or = 250 K) are associated with polarization differences greater than or = 6 K, approx. 50%, of the time over ocean and approx. 40% over land. In addition. over thick clouds the polarization difference at 37 GHz is rarely negligible. The polarization differences at 37 and 85 GHz do not stem from the surface but are generated in regions of relatively homogeneous clouds having high liquid water content. To interpret the observations, a radiative transfer model that includes the scattering by non-spherical particles is developed. based on the T-matrix approach and using the doubling and adding method. In addition to handling randomly and perfectly oriented particles, this model can also simulate the effect of partial orientation of the hydrometeors. Microwave brightness temperatures are simulated at SSM/I frequencies and are compared with the observations. Polarization differences of approx. 2 K can be simulated at 37 GHz over a rain layer, even using spherical drops. The polarization difference is larger for oriented non-spherical particles. The 85 GHz simulations are very sensitive to the ice phase of the cloud. Simulations with spherical particles or with randomly oriented non-spherical ice particles cannot replicate the observed polarization differences. However, with partially oriented non-spherical particles, the observed polarized signatures at 85 GHz are explained, and the sensitivity of the scattering characteristics to the particle size, asphericity, and orientation is analyzed. Implications on rain and ice retrievals are discussed.

Complete polarization characterization of single plasmonic nanoparticle enabled by a novel Dark-field Mueller matrix spectroscopy system

PubMed Central

Chandel, Shubham; Soni, Jalpa; Ray, Subir kumar; Das, Anwesh; Ghosh, Anirudha; Raj, Satyabrata; Ghosh, Nirmalya

2016-01-01

Information on the polarization properties of scattered light from plasmonic systems are of paramount importance due to fundamental interest and potential applications. However, such studies are severely compromised due to the experimental difficulties in recording full polarization response of plasmonic nanostructures. Here, we report on a novel Mueller matrix spectroscopic system capable of acquiring complete polarization information from single isolated plasmonic nanoparticle/nanostructure. The outstanding issues pertaining to reliable measurements of full 4 × 4 spectroscopic scattering Mueller matrices from single nanoparticle/nanostructures are overcome by integrating an efficient Mueller matrix measurement scheme and a robust eigenvalue calibration method with a dark-field microscopic spectroscopy arrangement. Feasibility of quantitative Mueller matrix polarimetry and its potential utility is illustrated on a simple plasmonic system, that of gold nanorods. The demonstrated ability to record full polarization information over a broad wavelength range and to quantify the intrinsic plasmon polarimetry characteristics via Mueller matrix inverse analysis should lead to a novel route towards quantitative understanding, analysis/interpretation of a number of intricate plasmonic effects and may also prove useful towards development of polarization-controlled novel sensing schemes. PMID:27212687

Modelling dust polarization observations of molecular clouds through MHD simulations

NASA Astrophysics Data System (ADS)

King, Patrick K.; Fissel, Laura M.; Chen, Che-Yu; Li, Zhi-Yun

2018-03-01

The BLASTPol observations of Vela C have provided the most detailed characterization of the polarization fraction p and dispersion in polarization angles S for a molecular cloud. We compare the observed distributions of p and S with those obtained in synthetic observations of simulations of molecular clouds, assuming homogeneous grain alignment. We find that the orientation of the mean magnetic field relative to the observer has a significant effect on the p and S distributions. These distributions for Vela C are most consistent with synthetic observations where the mean magnetic field is close to the line of sight. Our results point to apparent magnetic disorder in the Vela C molecular cloud, although it can be due to either an inclination effect (i.e. observing close to the mean field direction) or significant field tangling from strong turbulence/low magnetization. The joint correlations of p with column density and of S with column density for the synthetic observations generally agree poorly with the Vela C joint correlations, suggesting that understanding these correlations requires a more sophisticated treatment of grain alignment physics.

Static Analysis of Large-Scale Multibody System Using Joint Coordinates and Spatial Algebra Operator

PubMed Central

Omar, Mohamed A.

2014-01-01

Initial transient oscillations inhibited in the dynamic simulations responses of multibody systems can lead to inaccurate results, unrealistic load prediction, or simulation failure. These transients could result from incompatible initial conditions, initial constraints violation, and inadequate kinematic assembly. Performing static equilibrium analysis before the dynamic simulation can eliminate these transients and lead to stable simulation. Most exiting multibody formulations determine the static equilibrium position by minimizing the system potential energy. This paper presents a new general purpose approach for solving the static equilibrium in large-scale articulated multibody. The proposed approach introduces an energy drainage mechanism based on Baumgarte constraint stabilization approach to determine the static equilibrium position. The spatial algebra operator is used to express the kinematic and dynamic equations of the closed-loop multibody system. The proposed multibody system formulation utilizes the joint coordinates and modal elastic coordinates as the system generalized coordinates. The recursive nonlinear equations of motion are formulated using the Cartesian coordinates and the joint coordinates to form an augmented set of differential algebraic equations. Then system connectivity matrix is derived from the system topological relations and used to project the Cartesian quantities into the joint subspace leading to minimum set of differential equations. PMID:25045732

Full Scale RC Beam-Column Joints Strengthened with Steel Reinforced Polymer Systems

NASA Astrophysics Data System (ADS)

De Vita, Alessandro; Napoli, Annalisa; Realfonzo, Roberto

2017-07-01

This paper presents the results of an experimental campaign performed at the Laboratory of Materials and Structural Testing of the University of Salerno (Italy) in order to investigate the seismic performance of RC beam-column joints strengthened with Steel Reinforced Polymer (SRP) systems. With the aim to represent typical façade frames’ beam-column subassemblies found in existing RC buildings, specimens were provided with two short beam stubs orthogonal to the main beam and were designed with inadequate seismic details. Five members were strengthened by using two different SRP layouts while the remaining ones were used as benchmarks. Once damaged, two specimens were also repaired, retrofitted with SRP and subjected to cyclic test again. The results of cyclic tests performed on SRP strengthened joints are examined through a comparison with the outcomes of the previous experimental program including companion specimens not provided with transverse beam stubs and strengthened by Carbon Fiber Reinforced Polymer (CFRP) systems. In particular, both qualitative and quantitative considerations about the influence of the confining effect provided by the secondary beams on the joint response, the suitability of all the adopted strengthening solutions (SRP/CFRP systems), the performances and the failure modes experienced in the several cases studied are provided.

Space Station Freedom electrical power system hardware commonality with the United States Polar Platform

NASA Technical Reports Server (NTRS)

Rieker, Lorra L.; Haraburda, Francis M.

1989-01-01

Information is presented on how the concept of commonality is being implemented with respect to electric power system hardware for the Space Station Freedom and the U.S. Polar Platform. Included is a historical account of the candidate common items which have the potential to serve the same power system functions on both Freedom and the Polar Platform. The Space Station program and objectives are described, focusing on the test and development responsibilities. The program definition and preliminary design phase and the design and development phase are discussed. The goal of this work is to reduce the program cost.

Internally supported flexible duct joint. [device for conducting fluids in high pressure systems

NASA Technical Reports Server (NTRS)

Kuhn, R. F., Jr. (Inventor)

1975-01-01

An internally supported, flexible duct joint for use in conducting fluids under relatively high pressures in systems where relatively large deflection angles must be accommodated is presented. The joint includes a flexible tubular bellows and an elongated base disposed within the bellows. The base is connected through radiating struts to the bellows near mid-portion and to each of the opposite end portions of the bellows through a pivotal connecting body. A motion-controlling linkage is provided for linking the connecting bodies, whereby angular displacement of the joint is controlled and uniformity in the instantaneous bend radius of the duct is achieved as deflection is imposed.

Degenerative joint disease: multiple joint involvement in young and mature dogs.

PubMed

Olsewski, J M; Lust, G; Rendano, V T; Summers, B A

1983-07-01

Radiologic, pathologic, and ancillary methods were used to determine the occurrence of degenerative joint disease involving multiple joints of immature and adult dogs. Animals were selected for the development of hip joint dysplasia and chronic degenerative joint disease. Of disease-prone dogs, 82% (45 of 55 dogs) had radiologic changes, indicative of hip dysplasia, by 1 year of age. At necropsy, more abnormal joints were identified than by radiographic examination. Among 92 dogs between 3 to 11 months of age that had joint abnormalities, 71% had hip joint involvement; 38%, shoulder joint involvement; 22%, stifle joint involvement; and 40% had multiple joint involvement. Polyarthritis was asymptomatic and unexpected. Radiographic examination of older dogs also revealed evidence of degenerative joint disease in many joints. Multiple joint involvement was substantiated at necropsy of young and mature dogs. A similar pattern of polyarticular osteoarthritis was revealed in a survey (computer search) of necropsy reports from medical case records of 100 adult and elderly dogs. Usually, the joint disease was an incidental observation, unrelated to the clinical disease or to the cause of death. The frequent occurrence of degenerative changes in several joints of dogs aged 6 months to 17 years indicated that osteoarthritis may be progressive in these joints and raises the possibility that systemic factors are involved in the disease process.

Development Requirements for Spacesuit Elbow Joint

NASA Technical Reports Server (NTRS)

Peters, Benjamin

2017-01-01

Functional Requirements for spacesuit elbow joint:1) The system is a conformal, single-axis spacesuit pressurized joint that encloses the elbow joint of the suited user and uses a defined interface to connect to the suit systems on either side of the joint.2) The system shall be designed to bear the loads incurred from the internal pressure of the system, as well as the expected loads induced by the user while enabling the user move the joint through the required range of motion. The joint torque of the system experienced by the user shall remain at or below the required specification for the entire range of motion.3) The design shall be constructed, at a minimum, as a two-layer system. The internal, air-tight layer shall be referred to as the bladder, and the layer on the unpressurized side of the bladder shall be referred to as the restraint. The design of the system may include additional features or layers, such as axial webbing, to meet the overall requirements of the design.

Expansion joint for guideway for magnetic levitation transportation system

DOEpatents

Rossing, Thomas D.

1993-01-01

An expansion joint that allows a guideway of a magnetic levitation transportation system to expand and contract while minimizing transients occurring in the magnetic lift and drag forces acting on a magnetic levitation vehicle traveling over the joint includes an upper cut or recess extending downwardly from the upper surface of the guideway and a non-intersecting lower cut or recess that extends upwardly from the lower surface of the guideway. The sidewalls of the cuts can be parallel to each other and the vertical axis of the guideway; the depth of the lower cut can be greater than the depth of the upper cut; and the overall combined lengths of the cuts can be greater than the thickness of the guideway from the upper to lower surface so that the cuts will overlap, but be spaced apart from each other. The distance between the cuts can be determined on the basis of the force transients and the mechanical behavior of the guideway. A second pair of similarly configured upper and lower cuts may be disposed in the guideway; the expansion joint may consist of two upper cuts and one lower cut; or the cuts may have non-parallel, diverging sidewalls so that the cuts have a substantially dove-tail shape.

Expansion joint for guideway for magnetic levitation transportation system

DOEpatents

Rossing, T.D.

1993-02-09

An expansion joint that allows a guideway of a magnetic levitation transportation system to expand and contract while minimizing transients occurring in the magnetic lift and drag forces acting on a magnetic levitation vehicle traveling over the joint includes an upper cut or recess extending downwardly from the upper surface of the guideway and a non-intersecting lower cut or recess that extends upwardly from the lower surface of the guideway. The side walls of the cuts can be parallel to each other and the vertical axis of the guideway; the depth of the lower cut can be greater than the depth of the upper cut; and the overall combined lengths of the cuts can be greater than the thickness of the guideway from the upper to lower surface so that the cuts will overlap, but be spaced apart from each other. The distance between the cuts can be determined on the basis of the force transients and the mechanical behavior of the guideway. A second pair of similarly configured upper and lower cuts may be disposed in the guideway; the expansion joint may consist of two upper cuts and one lower cut; or the cuts may have non-parallel, diverging side walls so that the cuts have a substantially dove-tail shape.

Joint Instability and Osteoarthritis

PubMed Central

Blalock, Darryl; Miller, Andrew; Tilley, Michael; Wang, Jinxi

2015-01-01

Joint instability creates a clinical and economic burden in the health care system. Injuries and disorders that directly damage the joint structure or lead to joint instability are highly associated with osteoarthritis (OA). Thus, understanding the physiology of joint stability and the mechanisms of joint instability-induced OA is of clinical significance. The first section of this review discusses the structure and function of major joint tissues, including periarticular muscles, which play a significant role in joint stability. Because the knee, ankle, and shoulder joints demonstrate a high incidence of ligament injury and joint instability, the second section summarizes the mechanisms of ligament injury-associated joint instability of these joints. The final section highlights the recent advances in the understanding of the mechanical and biological mechanisms of joint instability-induced OA. These advances may lead to new opportunities for clinical intervention in the prevention and early treatment of OA. PMID:25741184

Joint instability and osteoarthritis.

PubMed

Blalock, Darryl; Miller, Andrew; Tilley, Michael; Wang, Jinxi

2015-01-01

Joint instability creates a clinical and economic burden in the health care system. Injuries and disorders that directly damage the joint structure or lead to joint instability are highly associated with osteoarthritis (OA). Thus, understanding the physiology of joint stability and the mechanisms of joint instability-induced OA is of clinical significance. The first section of this review discusses the structure and function of major joint tissues, including periarticular muscles, which play a significant role in joint stability. Because the knee, ankle, and shoulder joints demonstrate a high incidence of ligament injury and joint instability, the second section summarizes the mechanisms of ligament injury-associated joint instability of these joints. The final section highlights the recent advances in the understanding of the mechanical and biological mechanisms of joint instability-induced OA. These advances may lead to new opportunities for clinical intervention in the prevention and early treatment of OA.

Derivation of global vegetation biophysical parameters from EUMETSAT Polar System

NASA Astrophysics Data System (ADS)

García-Haro, Francisco Javier; Campos-Taberner, Manuel; Muñoz-Marí, Jordi; Laparra, Valero; Camacho, Fernando; Sánchez-Zapero, Jorge; Camps-Valls, Gustau

2018-05-01

This paper presents the algorithm developed in LSA-SAF (Satellite Application Facility for Land Surface Analysis) for the derivation of global vegetation parameters from the AVHRR (Advanced Very High Resolution Radiometer) sensor on board MetOp (Meteorological-Operational) satellites forming the EUMETSAT (European Organization for the Exploitation of Meteorological Satellites) Polar System (EPS). The suite of LSA-SAF EPS vegetation products includes the leaf area index (LAI), the fractional vegetation cover (FVC), and the fraction of absorbed photosynthetically active radiation (FAPAR). LAI, FAPAR, and FVC characterize the structure and the functioning of vegetation and are key parameters for a wide range of land-biosphere applications. The algorithm is based on a hybrid approach that blends the generalization capabilities offered by physical radiative transfer models with the accuracy and computational efficiency of machine learning methods. One major feature is the implementation of multi-output retrieval methods able to jointly and more consistently estimate all the biophysical parameters at the same time. We propose a multi-output Gaussian process regression (GPRmulti), which outperforms other considered methods over PROSAIL (coupling of PROSPECT and SAIL (Scattering by Arbitrary Inclined Leaves) radiative transfer models) EPS simulations. The global EPS products include uncertainty estimates taking into account the uncertainty captured by the retrieval method and input errors propagation. A sensitivity analysis is performed to assess several sources of uncertainties in retrievals and maximize the positive impact of modeling the noise in training simulations. The paper discusses initial validation studies and provides details about the characteristics and overall quality of the products, which can be of interest to assist the successful use of the data by a broad user's community. The consistent generation and distribution of the EPS vegetation products will

Coherent UDWDM PON with joint subcarrier reception at OLT.

PubMed

Kottke, Christoph; Fischer, Johannes Karl; Elschner, Robert; Frey, Felix; Hilt, Jonas; Schubert, Colja; Schmidt, Daniel; Wu, Zifeng; Lankl, Berthold

2014-07-14

In this contribution, we report on the experimental investigation of an ultra-dense wavelength-division multiplexing (UDWDM) upstream link with up to 700 × 2.488 Gb/s polarization-division multiplexing differential quadrature phase-shift keying parallel upstream user channels transmitted over 80 km of standard single-mode fiber. We discuss challenges of the digital signal processing in the optical line terminal arising from the joint reception of several upstream user channels. We present solutions for resource and cost-efficient realization of the required channel separation, matched filtering, down-conversion and decimation as well as realization of the clock recovery and polarization demultiplexing for each individual channel.

Real-time polarization imaging algorithm for camera-based polarization navigation sensors.

PubMed

Lu, Hao; Zhao, Kaichun; You, Zheng; Huang, Kaoli

2017-04-10

Biologically inspired polarization navigation is a promising approach due to its autonomous nature, high precision, and robustness. Many researchers have built point source-based and camera-based polarization navigation prototypes in recent years. Camera-based prototypes can benefit from their high spatial resolution but incur a heavy computation load. The pattern recognition algorithm in most polarization imaging algorithms involves several nonlinear calculations that impose a significant computation burden. In this paper, the polarization imaging and pattern recognition algorithms are optimized through reduction to several linear calculations by exploiting the orthogonality of the Stokes parameters without affecting precision according to the features of the solar meridian and the patterns of the polarized skylight. The algorithm contains a pattern recognition algorithm with a Hough transform as well as orientation measurement algorithms. The algorithm was loaded and run on a digital signal processing system to test its computational complexity. The test showed that the running time decreased to several tens of milliseconds from several thousand milliseconds. Through simulations and experiments, it was found that the algorithm can measure orientation without reducing precision. It can hence satisfy the practical demands of low computational load and high precision for use in embedded systems.

Polarization feedback laser stabilization

DOEpatents

Esherick, Peter; Owyoung, Adelbert

1988-01-01

A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other.

Musculoskeletal system of the neck of the polar bear (Ursus maritimus) and the Malayan bear (Helarctos malayanus).

PubMed

Endo, H; Kakegawa, Y; Taru, H; Sasaki, M; Hayashi, Y; Yamamoto, M; Arishima, K

2001-01-01

The gross anatomical study was undertaken in the musculoskeletal system of the neck of the polar bear, and the findings were compared with those of the Malayan bear. The Musculus splenius and the M. trapezius were well-developed in the polar bear. The long neck of the polar bear consisted mainly of the M. splenius with the M. biventer cervicis and the M. complexus lying tightly underneath. The cervical vertebrae possessed huge ventral tubercle in the ventral part of the transverse process in the polar bear. These morphological characteristics suggest that the polar bear may rotate and bend the skull and the long cervical vertebrae. We postulate that the polar bear has evolved the high-mobility long neck to adapt for swimming. Unlike the polar bear, the Malayan bear has not specialized in the neck structure.

Nervous system excitability and joint stiffness following short-term dynamic ankle immobilization.

PubMed

Stirling, Alyssa M; McBride, Jeffrey M; Merritt, Edward K; Needle, Alan R

2018-01-01

Joint immobilization has been demonstrated to modify neural excitability in subsets of healthy populations, leading to disinhibition of cortical and reflexive pathways. However, these findings may have limited clinical application as most models have investigated casting and rigid immobilization, while many musculoskeletal injuries often utilize dynamic immobilization devices such as boot immobilizers and pneumatic splints that allow for modified ambulation. We therefore aimed to determine the short-term effects of ambulation in ankle immobilization devices on nervous system excitability and stiffness in able-bodied individuals. A repeated-measures design was implemented where 12 healthy individuals were tested for cortical excitability to the ankle musculature using transcranial magnetic stimulation, reflexive excitability using the Hoffmann reflex, and ankle joint stiffness using arthrometry before and after 30min of ambulation with a boot immobilizer, pneumatic leg splint, or barefoot. Motor evoked potential (MEP), cortical silent period (CSP), H max to M max ratio, and ankle joint displacement were extracted as dependent variables. Results indicated that despite the novel motor demands of walking in immobilization devices, no significant changes in cortical excitability (F≥0.335, P≥0.169), reflexive excitability (F≥0.027, P≥0.083), or joint stiffness (F≥0.558, P≥0.169) occurred. These findings indicate that short-term ambulation in dynamic immobilization devices does not modify neural excitability despite forced constraints on the sensorimotor system. We may therefore conclude that modifications to neural excitability in previous immobilization models are mediated by long-term nervous system plasticity rather than acute mechanisms, and there appear to be no robust changes in corticomotor or spinal excitability acutely posed by ambulation with immobilization devices. Copyright © 2017 Elsevier B.V. All rights reserved.

Variable polarity plasma arc welding on the Space Shuttle external tank

NASA Technical Reports Server (NTRS)

Nunes, A. C., Jr.; Bayless, E. O., Jr.; Jones, C. S., III; Munafo, P. M.; Biddle, A. P.; Wilson, W. A.

1984-01-01

Variable polarity plasma arc (VPPA) techniques used at NASA's Marshall Space Flight Center for the fabrication of the Space Shuttle External Tank are presentedd. The high plasma arc jet velocities of 300-2000 m/s are produced by heating the plasma gas as it passes through a constraining orifice, with the plasma arc torch becoming a miniature jet engine. As compared to the GTA jet, the VPPA has the following advantages: (1) less sensitive to contamination, (2) a more symmetrical fusion zone, and (3) greater joint penetration. The VPPA welding system is computerized, operating with a microprocessor, to set welding variables in accordance with set points inputs, including the manipulator and wire feeder, as well as torch control and power supply. Some other VPPA welding technique advantages are: reduction in weld repair costs by elimination of porosity; reduction of joint preparation costs through elimination of the need to scrape or file faying surfaces; reduction in depeaking costs; eventual reduction of the 100 percent-X-ray inspection requirements. The paper includes a series of schematic and block diagrams.

An in vitro test system for compounds that modulate human inflammatory macrophage polarization.

PubMed

Shiratori, Hiromi; Feinweber, Carmen; Luckhardt, Sonja; Wallner, Nadja; Geisslinger, Gerd; Weigert, Andreas; Parnham, Michael J

2018-06-16

Macrophages undergo activation by pathophysiological stimuli to pro-inflammatory and bactericidal, or wound-healing and anti-inflammatory phenotypes, termed M1 or M2, respectively. Dysregulation of the M1-M2 balance is often associated with inflammatory diseases. Therefore, mechanisms of macrophage polarization may reveal new drug targets. We profiled six compounds with claimed modulatory effects on macrophage polarization using peripheral blood monocyte-derived macrophages. Based on the distinct mRNA or protein expression in macrophages stimulated either with M1 [lipopolysaccharide (LPS) + interferon-γ, IFNγ] or M2 interleukin-4 (IL-4) stimuli, we selected a combination of M1 (IL1β, tumor necrosis factor-α,TNFα, CC chemokine receptor 7, CCR7 and CD80) and M2 (chemokine (C-C motif) ligand 22, CCL22, CD200R and mannose receptor C type 1, MRC1) markers to monitor drug effects on "M1 polarization" or cells "pre-polarized to M1". Azithromycin (25-50μM), tofacitinib (2.5-5μM), hydroxychloroquine (40µg/ml) and pioglitazone (15-60μM) exhibit an anti-inflammatory profile because they downregulated M1 markers and upregulated some M2 markers when given both before and after M1 polarization. Lovastatin given before M1 polarization downregulated M1 marker genes but enhanced the M1 phenotype in macrophages pre-polarized with LPS and IFNγ. Methotrexate (1.25-5μM) did not modulate macrophage polarization. We have, thus, established a test system suitable to identify novel compounds or repurposed drugs that modulate inflammatory macrophage plasticity. Compounds with potential to reduce expression of molecules involved in inflammatory T cell activation (IL-1β, TNFα, CD80), while enhancing production of a major chemokine involved in recruitment of Tregs (CCL22) may be of interest for treating chronic inflammatory diseases. Copyright © 2018. Published by Elsevier B.V.

Joint Aspiration (Arthrocentesis)

MedlinePlus

... arthritis, or JRA), systemic lupus erythematosus (SLE), and Lyme disease. Joint aspiration is diagnostic but it also can ... topic for: Parents Kids Teens Evaluate Your Child's Lyme Disease Risk Living With Lupus Bones, Muscles, and Joints ...

Joint Technical Architecture for Robotic Systems (JTARS)-Final Report

NASA Technical Reports Server (NTRS)

Bradley, Arthur T.; Holloway, Sidney E., III

2006-01-01

This document represents the final report for the Joint Technical Architecture for Robotic Systems (JTARS) project, funded by the Office of Exploration as part of the Intramural Call for Proposals of 2005. The project was prematurely terminated, without review, as part of an agency-wide realignment towards the development of a Crew Exploration Vehicle (CEV) and meeting the near-term goals of lunar exploration.

A new three-dimensional, print-on-demand temporomandibular prosthetic total joint replacement system: Preliminary outcomes.

PubMed

Dimitroulis, George; Austin, Stephen; Sin Lee, Peter Vee; Ackland, David

2018-05-16

The aim of this study is to present the preliminary clinical data on the OMX Temporomandibular Joint (TMJ) Prosthetic total joint replacement system. A prospective, cohort, clinical study was undertaken of consecutive adult patients with Category 5 end-stage joint disease who were implanted with the OMX TMJ prosthesis between May 2015 and April 2017. A total of 50 devices were implanted in 38 patients, with 12 patients receiving bilateral prosthetic joints. There were 31 females and 7 males in this cohort, who ranged in age from 20 to 66 years, with a mean of 43.8 years (±14.0 years). Ten of the 50 prosthetic joints (20%) were fully customized, while the remaining were patient matched using virtual planning software. Based on a mean follow-up period of 15.3 months (range 12-24 months) following the TMJ total joint replacement, preliminary results suggest the OMX TMJ prosthesis has made a positive impact on clinical outcomes, with a mean 74.4% reduction in joint pain levels and significant improvements (p < 0.05) in jaw function as measured by the visual analogue scales for mouth opening (30.8%), diet (77.1%), and function (59.2%). No device failures were reported during the study period. This study suggests that the print-on-demand OMX TMJ prosthesis, designed for rapid delivery of both patient-matched and fully customize devices, represents a safe, reliable and versatile implantable joint replacement system for the treatment of category 5 end-stage TMJ disease. Copyright © 2018 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Sliding mode control for a two-joint coupling nonlinear system based on extended state observer.

PubMed

Zhao, Ling; Cheng, Haiyan; Wang, Tao

2018-02-01

A two-joint coupling nonlinear system driven by pneumatic artificial muscles is introduced in this paper. A sliding mode controller with extended state observer is proposed to cope with nonlinearities and disturbances for the two-joint coupling nonlinear system. In addition, convergence of the extended state observer is presented and stability analysis of the closed-loop system is also demonstrated with the sliding mode controller. Lastly, some experiments are carried out to show the reality effectiveness of the proposed method. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Polarization feedback laser stabilization

DOEpatents

Esherick, P.; Owyoung, A.

1987-09-28

A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other. 4 figs.

Hydrogen effects in duplex stainless steel welded joints - electrochemical studies

NASA Astrophysics Data System (ADS)

Michalska, J.; Łabanowski, J.; Ćwiek, J.

2012-05-01

In this work results on the influence of hydrogen on passivity and corrosion resistance of 2205 duplex stainless steel (DSS) welded joints are described. The results were discussed by taking into account three different areas on the welded joint: weld metal (WM), heat-affected zone (HAZ) and parent metal. The corrosion resistance was qualified with the polarization curves registered in a synthetic sea water. The conclusion is that, hydrogen may seriously deteriorate the passive film stability and corrosion resistance to pitting of 2205 DSS welded joints. The presence of hydrogen in passive films increases corrosion current density and decreases the potential of the film breakdown. It was also found that degree of susceptibility to hydrogen degradation was dependent on the hydrogen charging conditions. WM region has been revealed as the most sensitive to hydrogen action.

Joint Precision Approach and Landing System Increment 1A (JPALS Inc 1A)

DTIC Science & Technology

2015-12-01

Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-238 Joint Precision Approach and Landing System Increment 1A (JPALS Inc 1A) As of FY 2017...President’s Budget Defense Acquisition Management Information Retrieval (DAMIR) March 10, 2016 11:30:56 UNCLASSIFIED JPALS Inc 1A December 2015 SAR...Fiscal Year FYDP - Future Years Defense Program ICE - Independent Cost Estimate IOC - Initial Operational Capability Inc - Increment JROC - Joint

A new technique for repair of a dislocated sternoclavicular joint using a sternal tension cable system.

PubMed

Janson, Jacques T; Rossouw, Gawie J

2013-02-01

An unstable anterior or posterior sternoclavicular joint dislocation can cause severe morbidity with poor shoulder movement and strength. These dislocations need to be repaired, which can be challenging. Many different procedures have been described to obtain a stable joint fixation with varying results. We report a new technique for repairing a sternoclavicular joint dislocation by using a figure-of-eight sternal cable system. This procedure is relatively simple and reproducible to create a stable and functional sternoclavicular joint. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Social-Cultural-Historical Contradictions in an L2 Listening Lesson: A Joint Activity System Analysis

ERIC Educational Resources Information Center

Cross, Jeremy

2011-01-01

Informed and inspired by neo-Vygotskian theory, this article outlines a study exploiting a contemporary conceptualization of Wells's (2002) joint activity system model as an exploratory framework for examining and depicting the social-cultural-historical contradictions in second-language (L2) learners' joint activity. The participants were a pair…

Space Station Freedom electrical power system hardware commonality with the United States Polar Platform

NASA Technical Reports Server (NTRS)

Rieker, Lorra L.; Haraburda, Francis M.

1989-01-01

The National Aeronautics and Space Administration has adopted the policy to achieve the maximum practical level of commonality for the Space Station Freedom program in order to significantly reduce life cycle costs. Commonality means using identical or similar hardware/software for meeting common sets of functionally similar requirements. Information on how the concept of commonality is being implemented with respect to electric power system hardware for the Space Station Freedom and the U.S. Polar Platform is presented. Included is a historical account of the candidate common items which have the potential to serve the same power system functions on both Freedom and the Polar Platform.

Electronic polarization-division demultiplexing based on digital signal processing in intensity-modulation direct-detection optical communication systems.

PubMed

Kikuchi, Kazuro

2014-01-27

We propose a novel configuration of optical receivers for intensity-modulation direct-detection (IM · DD) systems, which can cope with dual-polarization (DP) optical signals electrically. Using a Stokes analyzer and a newly-developed digital signal-processing (DSP) algorithm, we can achieve polarization tracking and demultiplexing in the digital domain after direct detection. Simulation results show that the power penalty stemming from digital polarization manipulations is negligibly small.

Polarized-interferometer feasibility study

NASA Technical Reports Server (NTRS)

Raab, F. H.

1983-01-01

The feasibility of using a polarized-interferometer system as a rendezvous and docking sensor for two cooperating spacecraft was studied. The polarized interferometer is a radio frequency system for long range, real time determination of relative position and attitude. Range is determined by round trip signal timing. Direction is determined by radio interferometry. Relative roll is determined from signal polarization. Each spacecraft is equipped with a transponder and an antenna array. The antenna arrays consist of four crossed dipoles that can transmit or receive either circularly or linearly polarized signals. The active spacecraft is equipped with a sophisticated transponder and makes all measurements. The transponder on the passive spacecraft is a relatively simple repeater. An initialization algorithm is developed to estimate position and attitude without any a priori information. A tracking algorithm based upon minimum variance linear estimators is also developed. Techniques to simplify the transponder on the passive spacecraft are investigated and a suitable configuration is determined. A multiple carrier CW signal format is selected. The dependence of range accuracy and ambiguity resolution error probability are derived and used to design a candidate system. The validity of the design and the feasibility of the polarized interferometer concept are verified by simulation.

JANNAF 35th Combustion Subcommittee and 17th Propulsion Systems Hazards Subcommittee Meeting: Joint Sessions

NASA Technical Reports Server (NTRS)

Fry, Ronald S. (Editor); Gannaway, Mary T. (Editor); Rognan, Melanie (Editor)

1998-01-01

This publication is a compilation of 15 unclassified/unlimited technical papers presented at the 1998 meeting of the Joint Army-Navy-NASA-Air Force (JANNAF) Combustion Subcommittee (CS) and Propulsion Systems Hazards Subcommittee (PSHS) held jointly with the Airbreathing Propulsion Subcommittee (APS). The meeting was held on 7 - 11 December 1 998 at Raytheon Systems Company and the Marriott Hotel, Tucson, AZ. Topics covered include advanced ingredients and reaction kinetics in solid propellants and experimental diagnostic techniques.

Sensitivity of VIIRS Polarization Measurements

NASA Technical Reports Server (NTRS)

Waluschka, Eugene

2010-01-01

The design of an optical system typically involves a sensitivity analysis where the various lens parameters, such as lens spacing and curvatures, to name two parameters, are (slightly) varied to see what, if any, effect this has on the performance and to establish manufacturing tolerances. A sinular analysis was performed for the VIIRS instruments polarization measurements to see how real world departures from perfectly linearly polarized light entering VIIRS effects the polarization measurement. The methodology and a few of the results of this polarization sensitivity analysis are presented and applied to the construction of a single polarizer which will cover the VIIRS VIS/NIR spectral range. Keywords: VIIRS, polarization, ray, trace; polarizers, Bolder Vision, MOXTEK

Stokes image reconstruction for two-color microgrid polarization imaging systems.

PubMed

Lemaster, Daniel A

2011-07-18

The Air Force Research Laboratory has developed a new microgrid polarization imaging system capable of simultaneously reconstructing linear Stokes parameter images in two colors on a single focal plane array. In this paper, an effective method for extracting Stokes images is presented for this type of camera system. It is also shown that correlations between the color bands can be exploited to significantly increase overall spatial resolution. Test data is used to show the advantages of this approach over bilinear interpolation. The bounds (in terms of available reconstruction bandwidth) on image resolution are also provided.

Cooperative Adaptive Output Regulation for Second-Order Nonlinear Multiagent Systems With Jointly Connected Switching Networks.

PubMed

Liu, Wei; Huang, Jie

2018-03-01

This paper studies the cooperative global robust output regulation problem for a class of heterogeneous second-order nonlinear uncertain multiagent systems with jointly connected switching networks. The main contributions consist of the following three aspects. First, we generalize the result of the adaptive distributed observer from undirected jointly connected switching networks to directed jointly connected switching networks. Second, by performing a new coordinate and input transformation, we convert our problem into the cooperative global robust stabilization problem of a more complex augmented system via the distributed internal model principle. Third, we solve the stabilization problem by a distributed state feedback control law. Our result is illustrated by the leader-following consensus problem for a group of Van der Pol oscillators.

North Polar Cap

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site]

This image shows clouds and one of the many storm fronts common in the north polar region during spring and early summer. Note the linear nature of the clouds towards the top of the image, and the appearance of a large crater barely visible beneath the cloud cover.

Image information: VIS instrument. Latitude 86.5, Longitude 64.5 East (295.5 West). 40 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Imaging skeletal muscle with linearly polarized light

NASA Astrophysics Data System (ADS)

Li, X.; Ranasinghesagara, J.; Yao, G.

2008-04-01

We developed a polarization sensitive imaging system that can acquire reflectance images in turbid samples using incident light of different polarization states. Using this system, we studied polarization imaging on bovine sternomandibularis muscle strips using light of two orthogonal linearly polarized states. We found the obtained polarization sensitive reflectance images had interesting patterns depending on the polarization states. In addition, we computed four elements of the Mueller matrix from the acquired images. As a comparison, we also obtained polarization images of a 20% Intralipid"R" solution and compared the results with those from muscle samples. We found that the polarization imaging patterns from Intralipid solution can be described with a model based on single-scattering approximation. However, the polarization images in muscle had distinct patterns and can not be explained by this simple model. These results implied that the unique structural properties of skeletal muscle play important roles in modulating the propagation of polarized light.

MultiFocus Polarization Microscope (MF-PolScope) for 3D polarization imaging of up to 25 focal planes simultaneously

PubMed Central

Abrahamsson, Sara; McQuilken, Molly; Mehta, Shalin B.; Verma, Amitabh; Larsch, Johannes; Ilic, Rob; Heintzmann, Rainer; Bargmann, Cornelia I.; Gladfelter, Amy S.; Oldenbourg, Rudolf

2015-01-01

We have developed an imaging system for 3D time-lapse polarization microscopy of living biological samples. Polarization imaging reveals the position, alignment and orientation of submicroscopic features in label-free as well as fluorescently labeled specimens. Optical anisotropies are calculated from a series of images where the sample is illuminated by light of different polarization states. Due to the number of images necessary to collect both multiple polarization states and multiple focal planes, 3D polarization imaging is most often prohibitively slow. Our MF-PolScope system employs multifocus optics to form an instantaneous 3D image of up to 25 simultaneous focal-planes. We describe this optical system and show examples of 3D multi-focus polarization imaging of biological samples, including a protein assembly study in budding yeast cells. PMID:25837112

A portable liquid crystal-based polarized light system for the detection of organophosphorus nerve gas.

PubMed

He, Feng Jie; Liu, Hui Long; Chen, Long Cong; Xiong, Xing Liang

2018-03-01

Liquid crystal (LC)-based sensors have the advantageous properties of being fast, sensitive, and label-free, the results of which can be accessed directly only through the naked eye. However, the inherent disadvantages possessed by LC sensors, such as relying heavily on polarizing microscopes and the difficulty to quantify, have limited the possibility of field applications. Herein, we have addressed these issues by constructing a portable polarized detection system with constant temperature control. This system is mainly composed of four parts: the LC cell, the optics unit, the automatic temperature control unit, and the image processing unit. The LC cell was based on the ordering transitions of LCs in the presence of analytes. The optics unit based on the imaging principle of LCs was designed to substitute the polarizing microscope for the real-time observation. The image processing unit is expected to quantify the concentration of analytes. The results have shown that the presented system can detect dimethyl methyl phosphonate (a stimulant for organophosphorus nerve gas) within 25 s, and the limit of detection is about 10 ppb. In all, our portable system has potential in field applications.

A portable liquid crystal-based polarized light system for the detection of organophosphorus nerve gas

NASA Astrophysics Data System (ADS)

He, Feng Jie; Liu, Hui Long; Chen, Long Cong; Xiong, Xing Liang

2018-03-01

Liquid crystal (LC)-based sensors have the advantageous properties of being fast, sensitive, and label-free, the results of which can be accessed directly only through the naked eye. However, the inherent disadvantages possessed by LC sensors, such as relying heavily on polarizing microscopes and the difficulty to quantify, have limited the possibility of field applications. Herein, we have addressed these issues by constructing a portable polarized detection system with constant temperature control. This system is mainly composed of four parts: the LC cell, the optics unit, the automatic temperature control unit, and the image processing unit. The LC cell was based on the ordering transitions of LCs in the presence of analytes. The optics unit based on the imaging principle of LCs was designed to substitute the polarizing microscope for the real-time observation. The image processing unit is expected to quantify the concentration of analytes. The results have shown that the presented system can detect dimethyl methyl phosphonate (a stimulant for organophosphorus nerve gas) within 25 s, and the limit of detection is about 10 ppb. In all, our portable system has potential in field applications.

Polarization characteristics of an altazimuth sky scanner

NASA Technical Reports Server (NTRS)

Garrison, L. M.; Blaszczak, Z.; Green, A. E. S.

1980-01-01

A theoretical description of the polarization characteristics of an altazimuth sky scanner optical system based on Mueller-Stokes calculus is presented. This computer-driven optical system was designed to perform laboratory studies of skylight and of celestial objects during day or night, and has no space limitations; however, the two parallel 45 deg tilt mirrors introduce some intrinsic polarization. Therefore, proper data interpretation requires a theoretical understanding of the polarization features of the instrument and accurate experimental determination of the Mueller-Stokes matrix elements describing the polarizing and depolarizing action of the system.

Oxygen Abundances in the Rings of Polar-Ring Galaxies

NASA Astrophysics Data System (ADS)

Radtke, I. R.; Eskridge, P. B.; Pogge, R. W.

2003-05-01

Polar ring galaxies (PRGs) are typically early-type (S0 or E) galaxies surrounded by rings of gas, dust, and stars orbiting nearly perpendicular to the principle plane of the host galaxy (Whitmore et al. 1990 AJ 100 1489). Given that PRGs have two separate, perpendicular axes of rotation, it is clear on dynamical grounds that PRGs are the products of merger events between two galaxies, but are observed in a state where two distinct kinematic and morphological structures are still apparent. As such, they present a unique opportunity to study merger events in systems where the debris is not confused with material from the host. Our understanding of the relative importance of polar ring systems in the overall process of galaxy evolution is confounded by our lack of knowledge regarding the typical lifetimes and evolutionary histories of polar rings. A crucial factor for understanding the formation and evolution of PRGs is information regarding the elemental abundances of the ring material. Polar rings are typically rich in {\\protectH 2} regions. Optical spectroscopy of these {\\protectH 2} regions can tell us their density, temperature, and oxygen abundance. Our earlier work (Eskridge & Pogge 1997 ApJ 486 259) revealed roughly Solar oxygen abundances for {\\protectH 2} regions in the polar ring of NGC 2685. We have extended this project, and now have spectra for six PRGs. Analysis of the data for II Zw 73 and UGC 7576 reveal the polar rings of these galaxies to have {\\protectH 2} region oxygen abundances in the range 0.3 to 0.6 Solar, substantially less than found for NGC 2685. Abundances in this range are much easier to explain with conventional models of chemical enrichment and polar ring formation. We shall present results for our full sample. Taken as a whole, this sample will provide a clear foundation for the typical chemical enrichment patterns in polar rings, and thus provide a clearer understanding of the formation and evolution of these curious objects. We

Investigations of Polarization Dependent Loss in Polarization Modulated Analog Optical Links

DTIC Science & Technology

2015-12-29

including theory. The general system is discussed as well as the details for measuring and calculating polarization dependent loss in the system. A...modulation link setup…………………………………………………. 5 2.3 PDL Measurement Routine…………………………………………………………. 6 3 MISALIGNING THE MODULATION ARC...nonlinearities due to polarization distortion loss (PDL). A method for measuring PDL within the system is detailed. A number of experiments are performed

PolarHub: A Global Hub for Polar Data Discovery

NASA Astrophysics Data System (ADS)

Li, W.

2014-12-01

This paper reports the outcome of a NSF project in developing a large-scale web crawler PolarHub to discover automatically the distributed polar dataset in the format of OGC web services (OWS) in the cyberspace. PolarHub is a machine robot; its goal is to visit as many webpages as possible to find those containing information about polar OWS, extract this information and store it into the backend data repository. This is a very challenging task given huge data volume of webpages on the Web. Three unique features was introduced in PolarHub to make it distinctive from earlier crawler solutions: (1) a multi-task, multi-user, multi-thread support to the crawling tasks; (2) an extensive use of thread pool and Data Access Object (DAO) design patterns to separate persistent data storage and business logic to achieve high extendibility of the crawler tool; (3) a pattern-matching based customizable crawling algorithm to support discovery of multi-type geospatial web services; and (4) a universal and portable client-server communication mechanism combining a server-push and client pull strategies for enhanced asynchronous processing. A series of experiments were conducted to identify the impact of crawling parameters to the overall system performance. The geographical distribution pattern of all PolarHub identified services is also demonstrated. We expect this work to make a major contribution to the field of geospatial information retrieval and geospatial interoperability, to bridge the gap between data provider and data consumer, and to accelerate polar science by enhancing the accessibility and reusability of adequate polar data.

Joint Precision Approach and Landing System Nunn-McCurdy Breach Root Cause Analysis and Portfolio Assessment Metrics for DoD Weapons Systems. Volume 8

DTIC Science & Technology

2015-01-01

system that would help in adverse weather conditions. U.S. operations in Bosnia, which were run from a relatively austere airfield with limited air... operations beginning in 2013 (CVN21, Joint Strike Fighter, Joint Unmanned Combat Air System ). cAccording to multiple FAA ofcial planning documents...Positioning System Next Generation Operational Control System HMS Handheld, Manpack and Small Form Fit HUD Head up Display IAMD Integrated Air and

Dual-polarized light-field imaging micro-system via a liquid-crystal microlens array for direct three-dimensional observation.

PubMed

Xin, Zhaowei; Wei, Dong; Xie, Xingwang; Chen, Mingce; Zhang, Xinyu; Liao, Jing; Wang, Haiwei; Xie, Changsheng

2018-02-19

Light-field imaging is a crucial and straightforward way of measuring and analyzing surrounding light worlds. In this paper, a dual-polarized light-field imaging micro-system based on a twisted nematic liquid-crystal microlens array (TN-LCMLA) for direct three-dimensional (3D) observation is fabricated and demonstrated. The prototyped camera has been constructed by integrating a TN-LCMLA with a common CMOS sensor array. By switching the working state of the TN-LCMLA, two orthogonally polarized light-field images can be remapped through the functioned imaging sensors. The imaging micro-system in conjunction with the electric-optical microstructure can be used to perform polarization and light-field imaging, simultaneously. Compared with conventional plenoptic cameras using liquid-crystal microlens array, the polarization-independent light-field images with a high image quality can be obtained in the arbitrary polarization state selected. We experimentally demonstrate characters including a relatively wide operation range in the manipulation of incident beams and the multiple imaging modes, such as conventional two-dimensional imaging, light-field imaging, and polarization imaging. Considering the obvious features of the TN-LCMLA, such as very low power consumption, providing multiple imaging modes mentioned, simple and low-cost manufacturing, the imaging micro-system integrated with this kind of liquid-crystal microstructure driven electrically presents the potential capability of directly observing a 3D object in typical scattering media.

Polarization Control with Piezoelectric and LiNbO3 Transducers

NASA Astrophysics Data System (ADS)

Bradley, E.; Miles, E.; Loginov, B.; Vu, N.

Several Polarization control transducers have appeared on the market, and now automated, endless polarization control systems using these transducers are becoming available. Unfortunately it is not entirely clear what benchmark performance tests a polarization control system must pass, and the polarization disturbances a system must handle are open to some debate. We present quantitative measurements of realistic polarization disturbances and two benchmark tests we have successfully used to evaluate the performance of an automated, endless polarization control system. We use these tests to compare the performance of a system using piezoelectric transducers to that of a system using LiNbO3 transducers.

In vitro systems for the study of microtubule-based cell polarity in fission yeast.

PubMed

Taberner, Núria; Lof, Andries; Roth, Sophie; Lamers, Dimitry; Zeijlemaker, Hans; Dogterom, Marileen

2015-01-01

Establishment of cell polarity is essential for processes such as growth and division. In fission yeast, as well as other species, polarity factors travel at the ends of microtubules to cortical sites where they associate with the membrane and subsequently maintain a polarized activity pattern despite their ability to diffuse in the membrane. In this chapter we present methods to establish an in vitro system that captures the essential features of this process. This bottom-up approach allows us to identify the minimal molecular requirements for microtubule-based cell polarity. We employ microfabrication techniques combined with surface functionalization to create rigid chambers with affinity for proteins, as well as microfluidic techniques to create and shape emulsion droplets with functionalized lipid boundaries. Preliminary results are shown demonstrating that a properly organized microtubule cytoskeleton can be confined to these confined spaces, and proteins traveling at the ends of growing microtubules can be delivered to their boundaries. Copyright © 2015 Elsevier Inc. All rights reserved.

Study on the polarization scrambling time for ultra-high-speed optical fiber communication systems

NASA Astrophysics Data System (ADS)

Jia, Nan; Li, Tangjun; Zhong, Kangping; Gong, Taorong; Lu, Dan; Chen, Ming; Wang, Chen

2009-11-01

A 160Gbit/s optical time-division-multiplexing (OTDM) transmission system with polarization Scrambler is demonstrated experimentally. The Scrambler based on the structure of the all-fiber dynamic polarization controller (PolaRITE II by General Photonics Co.). The polarization controller is controlled accurately the peak scrambling frequencies and the corresponding half-wave voltages by home-made a singlechip circuit. Both theory and experience show that the rate of scrambler is related to the spectrum width, spectral distribution, modulation rate and so on. The rate of Scramble for broadband light would be much slower compare with narrowband light to carrying out depolarization. In the same width of spectrum, light with abundant spectrum would need a slower rate. The relationship between the Rate of Scrambler and the Character of different Lasers will be discussed by using Stokes parameters and Mueller matrix. And the experiments performed to verify the results of theoretical analysis results. The Scrambler can reduce Intersymbol Interference, Polarization Mode Dispersion (PMD) and Polarization Dependent Loss (PDL) that have are validated experimentally. Based on the Scrambler, the 160-Gb/s OTDM transmissions are successfully demonstrated.

Power and polarization dependences of ultra-narrow electromagnetically induced absorption (EIA) spectra of 85 Rb atoms in degenerate two-level system

NASA Astrophysics Data System (ADS)

Qureshi, Muhammad Mohsin; Rehman, Hafeez Ur; Noh, Heung-Ryoul; Kim, Jin-Tae

2016-05-01

We have investigated ultra-narrow EIA spectral features with respect to variations of polarizations and powers of pump laser beam in a degenerate two-level system of the transition of 85 Rb D2 transition line. Polarizations of the probe laser beam in two separate experiments were fixed at right circular and horizontal linear polarizations, respectively while the polarizations of the pump lasers were varied from initial polarizations same as the probe laser beams to orthogonal to probe polarizations. One homemade laser combined with AOMs was used to the pump and probe laser beams instead of two different lasers to overcome broad linewidths of the homemade lasers. Theoretically, probe absorption coefficients have been calculated from optical Bloch equations of the degenerate two level system prepared by a pump laser beam. In the case of the circular polarization, EIA signal was obtained as expected theoretically although both pump and probe beams have same polarization. The EIA signal become smaller as power increases and polarizations of the pump and probe beams were same. When the polarization of the pump beam was linear polarization, maximum EIA signal was obtained theoretically and experimentally. Experimental EIA spectral shapes with respect to variations of the pump beam polarization shows similar trends as the theoretical results.

Determination of Parachute Joint Factors using Seam and Joint Testing

NASA Technical Reports Server (NTRS)

Mollmann, Catherine

2015-01-01

This paper details the methodology for determining the joint factor for all parachute components. This method has been successfully implemented on the Capsule Parachute Assembly System (CPAS) for the NASA Orion crew module for use in determining the margin of safety for each component under peak loads. Also discussed are concepts behind the joint factor and what drives the loss of material strength at joints. The joint factor is defined as a "loss in joint strength...relative to the basic material strength" that occurs when "textiles are connected to each other or to metals." During the CPAS engineering development phase, a conservative joint factor of 0.80 was assumed for each parachute component. In order to refine this factor and eliminate excess conservatism, a seam and joint testing program was implemented as part of the structural validation. This method split each of the parachute structural joints into discrete tensile tests designed to duplicate the loading of each joint. Breaking strength data collected from destructive pull testing was then used to calculate the joint factor in the form of an efficiency. Joint efficiency is the percentage of the base material strength that remains after degradation due to sewing or interaction with other components; it is used interchangeably with joint factor in this paper. Parachute materials vary in type-mainly cord, tape, webbing, and cloth -which require different test fixtures and joint sample construction methods. This paper defines guidelines for designing and testing samples based on materials and test goals. Using the test methodology and analysis approach detailed in this paper, the minimum joint factor for each parachute component can be formulated. The joint factors can then be used to calculate the design factor and margin of safety for that component, a critical part of the design verification process.

Polarization-sensitive optical coherence tomography using continuous polarization modulation with arbitrary phase modulation amplitude

NASA Astrophysics Data System (ADS)

Lu, Zenghai; Kasaragod, Deepa K.; Matcher, Stephen J.

2012-03-01

We demonstrate theoretically and experimentally that the phase retardance and relative optic-axis orientation of a sample can be calculated without prior knowledge of the actual value of the phase modulation amplitude when using a polarization-sensitive optical coherence tomography system based on continuous polarization modulation (CPM-PS-OCT). We also demonstrate that the sample Jones matrix can be calculated at any values of the phase modulation amplitude in a reasonable range depending on the system effective signal-to-noise ratio. This has fundamental importance for the development of clinical systems by simplifying the polarization modulator drive instrumentation and eliminating its calibration procedure. This was validated on measurements of a three-quarter waveplate and an equine tendon sample by a fiber-based swept-source CPM-PS-OCT system.

High Temperature Stability of Dissimilar Metal Joints in Fission Surface Power Systems

NASA Technical Reports Server (NTRS)

Locci, Ivan E.; Nesbitt, James A.; Ritzert, Frank J.; Bowman, Cheryl L.

2007-01-01

Future generations of power systems for spacecraft and lunar surface systems will likely require a strong dependence on nuclear power. The design of a space nuclear power plant involves integrating together major subsystems with varying materia1 requirements. Refractory alloys are repeatedly considered for major structural components in space power reactor designs because refractory alloys retain their strength at higher temperatures than other classes of metals. The relatively higher mass and lower ductility of the refractory alloys make them less attractive for lower temperature subsystems in the power plant such as the power conversion system. The power conversion system would consist more likely of intermediate temperature Ni-based superalloys. One of many unanswered questions about the use of refractory alloys in a space power plant is how to transition from the use of the structural refractory alloy to more traditional structural alloys. Because deleterious phases can form when complex alloys are joined and operated at elevated temperatures, dissimilar material diffusion analyses of refractory alloys and superalloys are needed to inform designers about options of joint temperature and operational lifetime. Combinations of four superalloys and six refractory alloys were bonded and annealed at 1150 K and 1300 K to examine diffusional interactions in this study. Joints formed through hot pressing and hot isostatic pressing were compared. Results on newer alloys compared favorably to historical data. Diffusional stability is promising for some combinations of Mo-Re alloys and superalloys at 1150 K, but it appears that lower joint temperatures would be required for other refractory alloy couples.

Circular polarization survey of intermediate polars I. Northern targets in the range 17 h < RA < 23 h

NASA Astrophysics Data System (ADS)

Butters, O. W.; Katajainen, S.; Norton, A. J.; Lehto, H. J.; Piirola, V.

2009-03-01

Context: The origin, evolution, and ultimate fate of magnetic cataclysmic variables are poorly understood. It is largely the nature of the magnetic fields in these systems that leads to this poor understanding. Fundamental properties, such as the field strength and the axis alignment, are unknown in a majority of these systems. Aims: We undertake to put all the previous circular polarization measurements into context and systematically survey intermediate polars for signs of circular polarization, hence to get an indication of their true magnetic field strengths and try to understand the evolution of magnetic cataclysmic variables. Methods: We used the TurPol instrument at the Nordic Optical Telescope to obtain simultaneous UBVRI photo-polarimetric observations of a set of intermediate polars, during the epoch 2006 July 31-August 2. Results: Of this set of eight systems two (1RXS J213344.1+510725 and 1RXS J173021.5-055933) were found to show significant levels of circular polarization, varying with spin phase. Five others (V2306 Cyg, AO Psc, DQ Her, FO Aqr, and V1223 Sgr) show some evidence for circular polarization and variation of this with spin phase, whilst AE Aqr shows little evidence for polarized emission. We also report the first simultaneous UBVRI photometry of the newly identified intermediate polar 1RXS J173021.5-055933. Conclusions: Circular polarization may be ubiquitous in intermediate polars, albeit at a low level of one or two percent or less. It is stronger at longer wavelengths in the visible spectrum. Our results lend further support to the possible link between the presence of soft X-ray components and the detectability of circular polarization in intermediate polars. Based on observations obtained at the Nordic Optical Telescope at the Roque de los Muchachos Observatory in La Palma.

A joint encryption/watermarking system for verifying the reliability of medical images.

PubMed

Bouslimi, Dalel; Coatrieux, Gouenou; Cozic, Michel; Roux, Christian

2012-09-01

In this paper, we propose a joint encryption/water-marking system for the purpose of protecting medical images. This system is based on an approach which combines a substitutive watermarking algorithm, the quantization index modulation, with an encryption algorithm: a stream cipher algorithm (e.g., the RC4) or a block cipher algorithm (e.g., the AES in cipher block chaining (CBC) mode of operation). Our objective is to give access to the outcomes of the image integrity and of its origin even though the image is stored encrypted. If watermarking and encryption are conducted jointly at the protection stage, watermark extraction and decryption can be applied independently. The security analysis of our scheme and experimental results achieved on 8-bit depth ultrasound images as well as on 16-bit encoded positron emission tomography images demonstrate the capability of our system to securely make available security attributes in both spatial and encrypted domains while minimizing image distortion. Furthermore, by making use of the AES block cipher in CBC mode, the proposed system is compliant with or transparent to the DICOM standard.

Cost-Effective Mobile-Based Healthcare System for Managing Total Joint Arthroplasty Follow-Up.

PubMed

Bitsaki, Marina; Koutras, George; Heep, Hansjoerg; Koutras, Christos

2017-01-01

Long-term follow-up care after total joint arthroplasty is essential to evaluate hip and knee arthroplasty outcomes, to provide information to physicians and improve arthroplasty performance, and to improve patients' health condition. In this paper, we aim to improve the communication between arthroplasty patients and physicians and to reduce the cost of follow-up controls based on mobile application technologies and cloud computing. We propose a mobile-based healthcare system that provides cost-effective follow-up controls for primary arthroplasty patients through questions about symptoms in the replaced joint, questionnaires (WOMAC and SF-36v2) and the radiological examination of knee or hip joint. We also perform a cost analysis for a set of 423 patients that were treated in the University Clinic for Orthopedics in Essen-Werden. The estimation of healthcare costs shows significant cost savings (a reduction of 63.67% for readmission rate 5%) in both the University Clinic for Orthopedics in Essen-Werden and the state of North Rhine-Westphalia when the mobile-based healthcare system is applied. We propose a mHealth system to reduce the cost of follow-up assessments of arthroplasty patients through evaluation of diagnosis, self-monitoring, and regular review of their health status.

Towards an Analytical Framework for Understanding the Development of a Quality Assurance System in an International Joint Programme

ERIC Educational Resources Information Center

Zheng, Gaoming; Cai, Yuzhuo; Ma, Shaozhuang

2017-01-01

This paper intends to construct an analytical framework for understanding quality assurance in international joint programmes and to test it in a case analysis of a European--Chinese joint doctoral degree programme. The development of a quality assurance system for an international joint programme is understood as an institutionalization process…

Introduction to the special issue on the joint meeting of the 19th IEEE International Symposium on the Applications of Ferroelectrics and the 10th European Conference on the Applications of Polar Dielectrics.

PubMed

Tsurumi, Takaaki

2011-09-01

The joint meeting of the 19th IEEE International Symposium on the Applications of Ferroelectrics and the 10th European Conference on the Applications of Polar Dielectrics took place in Edinburgh from August 9-12, 2010. The conference was attended by 390 delegates from more than 40 different countries. There were 4 plenary speakers, 56 invited speakers, and a further 222 contributed oral presentations in 7 parallel session. In addition there were 215 poster presentations. Key topics addressed at the conference included piezoelectric materials, leadfree piezoelectrics, and multiferroics.

Folded optics with birefringent reflective polarizers

NASA Astrophysics Data System (ADS)

Wong, Timothy L.; Yun, Zhisheng; Ambur, Gregg; Etter, Jo

2017-06-01

Polymeric, birefringent reflective polarizers have been used to produce compact, mid-field-of-view eyepieces and wide field-of-view optics for virtual reality (VR) head-mounted displays using the "pancake" lens configuration. Multiple configurations for pancake lens systems are discussed as are their advantages and disadvantages relative to refractive systems. Polarization control is an important consideration and the polarizing effects of different components are discussed. Designs for mid-FOV and wide FOV are presented and additional benefits of using folded optics for virtual reality systems are explored.

Sky light polarization detection with linear polarizer triplet in light field camera inspired by insect vision.

PubMed

Zhang, Wenjing; Cao, Yu; Zhang, Xuanzhe; Liu, Zejin

2015-10-20

Stable information of a sky light polarization pattern can be used for navigation with various advantages such as better performance of anti-interference, no "error cumulative effect," and so on. But the existing method of sky light polarization measurement is weak in real-time performance or with a complex system. Inspired by the navigational capability of a Cataglyphis with its compound eyes, we introduce a new approach to acquire the all-sky image under different polarization directions with one camera and without a rotating polarizer, so as to detect the polarization pattern across the full sky in a single snapshot. Our system is based on a handheld light field camera with a wide-angle lens and a triplet linear polarizer placed over its aperture stop. Experimental results agree with the theoretical predictions. Not only real-time detection but simple and costless architecture demonstrates the superiority of the approach proposed in this paper.

Theoretical explanation of the polarization-converting system achieved by beam shaping and combination technique and its performance under high power conditions

NASA Astrophysics Data System (ADS)

Wang, Peng; Li, Xiao; Shang, YaPing; Xu, XiaoJun

2015-10-01

The fiber laser has very obvious advantages and broad applications in remote welding, 3D cutting and national defense compared with the traditional solid laser. But influenced by heat effect of gain medium, nonlinear effect, stress birefringence effect and other negative factors, it's very difficult to get high power linearly polarized laser just using a single laser. For these limitations a polarization-converting system is designed using beam shaping and combination technique which is able to transform naturally polarized laser to linearly polarized laser at real time to resolve difficulties of generating high-power linearly polarized laser from fiber lasers in this paper. The principle of the Gaussian beam changing into the hollow beam passing through two axicons and the combination of the Gaussian beam and the hollow beam is discussed. In the experimental verification the energy conversion efficiency reached 93.1% with a remarkable enhancement of the extinction ratio from 3% to 98% benefited from the high conversion efficiency of axicons and the system worked fine under high power conditions. The system also kept excellent far field divergence. The experiment phenomenon also agreed with the simulation quite well. The experiment proves that this polarization-converting system will not affect laser structure which controls easily and needs no feedback and controlling system with stable and reliable properties at the same time. It can absolutely be applied to the polarization-conversion of high power laser.

Development and Applications of a Self-Contained, Non-Invasive EVA Joint Angle and Muscle Fatigue Sensor System

NASA Technical Reports Server (NTRS)

Ranniger, C. U.; Sorenson, E. A.; Akin, D. L.

1995-01-01

The University of Maryland Space Systems Laboratory, as a participant in NASA's INSTEP program, is developing a non-invasive, self-contained sensor system which can provide quantitative measurements of joint angles and muscle fatigue in the hand and forearm. The goal of this project is to develop a system with which hand/forearm motion and fatigue metrics can be determined in various terrestrial and zero-G work environments. A preliminary study of the prototype sensor systems and data reduction techniques for the fatigue measurement system are presented. The sensor systems evaluated include fiberoptics, used to measure joint angle, surface electrodes, which measure the electrical signals created in muscle as it contracts; microphones, which measure the noise made by contracting muscle; and accelerometers, which measure the lateral muscle acceleration during contraction. The prototype sensor systems were used to monitor joint motion of the metacarpophalangeal joint and muscle fatigue in flexor digitorum superficialis and flexor carpi ulnaris in subjects performing gripping tasks. Subjects were asked to sustain a 60-second constant-contraction (isometric) exercise and subsequently to perform a repetitive handgripping task to failure. Comparison of the electrical and mechanical signals of the muscles during the different tasks will be used to evaluate the applicability of muscle signal measurement techniques developed for isometric contraction tasks to fatigue prediction in quasi-dynamic exercises. Potential data reduction schemes are presented.

Advancing Environmental Prediction Capabilities for the Polar Regions and Beyond during The Year of Polar Prediction

NASA Astrophysics Data System (ADS)

Werner, Kirstin; Goessling, Helge; Hoke, Winfried; Kirchhoff, Katharina; Jung, Thomas

2017-04-01

Environmental changes in polar regions open up new opportunities for economic and societal operations such as vessel traffic related to scientific, fishery and tourism activities, and in the case of the Arctic also enhanced resource development. The availability of current and accurate weather and environmental information and forecasts will therefore play an increasingly important role in aiding risk reduction and safety management around the poles. The Year of Polar Prediction (YOPP) has been established by the World Meteorological Organization's World Weather Research Programme as the key activity of the ten-year Polar Prediction Project (PPP; see more on www.polarprediction.net). YOPP is an internationally coordinated initiative to significantly advance our environmental prediction capabilities for the polar regions and beyond, supporting improved weather and climate services. Scheduled to take place from mid-2017 to mid-2019, the YOPP core phase covers an extended period of intensive observing, modelling, prediction, verification, user-engagement and education activities in the Arctic and Antarctic, on a wide range of time scales from hours to seasons. The Year of Polar Prediction will entail periods of enhanced observational and modelling campaigns in both polar regions. With the purpose to close the gaps in the conventional polar observing systems in regions where the observation network is sparse, routine observations will be enhanced during Special Observing Periods for an extended period of time (several weeks) during YOPP. This will allow carrying out subsequent forecasting system experiments aimed at optimizing observing systems in the polar regions and providing insight into the impact of better polar observations on forecast skills in lower latitudes. With various activities and the involvement of a wide range of stakeholders, YOPP will contribute to the knowledge base needed to managing the opportunities and risks that come with polar climate change.

Assessment of the Accounting and Joint Accounting/Computer Information Systems Programs.

ERIC Educational Resources Information Center

Appiah, John; Cernigliaro, James; Davis, Jeffrey; Gordon, Millicent; Richards, Yves; Santamaria, Fernando; Siegel, Annette; Lytle, Namy; Wharton, Patrick

This document presents City University of New York LaGuardia Community College's Department of Accounting and Managerial Studies assessment of its accounting and joint accounting/computer information systems programs report, and includes the following items: (1) description of the mission and goals of the Department of Accounting and Managerial…

Beyond the Joint: The Role of Central Nervous System Reorganizations in Chronic Musculoskeletal Disorders.

PubMed

Roy, Jean-Sébastien; Bouyer, Laurent J; Langevin, Pierre; Mercier, Catherine

2017-11-01

To a large extent, management of musculoskeletal disorders has traditionally focused on structural dysfunctions found within the musculoskeletal system, mainly around the affected joint. While a structural-dysfunction approach may be effective for musculoskeletal conditions in some populations, especially in acute presentations, its effectiveness remains limited in patients with recurrent or chronic musculoskeletal pain. Numerous studies have shown that the human central nervous system can undergo plastic reorganizations following musculoskeletal disorders; however, they can be maladaptive and contribute to altered joint control and chronic pain. In this Viewpoint, the authors argue that to improve rehabilitation outcomes in patients with chronic musculoskeletal pain, a global view of the disorder that incorporates both central (neural) and peripheral (joint-level) changes is needed. The authors also discuss the challenge of evaluating and rehabilitating central changes and the need for large, high-level studies to evaluate approaches incorporating central and peripheral changes and emerging therapies. J Orthop Sports Phys Ther 2017;47(11):817-821. doi:10.2519/jospt.2017.0608.

75 FR 6250 - ITS Joint Program Office; Intelligent Transportation Systems Program Advisory Committee; Notice...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-08

... DEPARTMENT OF TRANSPORTATION ITS Joint Program Office; Intelligent Transportation Systems Program... the Intelligent Transportation Systems (ITS) Program Advisory Committee (ITSPAC). The Web conference... Transportation on all matters relating to the study, development, and implementation of intelligent...

Shaping future Naval warfare with unmanned systems, the impact across the fleet, and joint considerations

NASA Astrophysics Data System (ADS)

Hudson, E. C.; Johnson, Gordon; Summey, Delbert C.; Portmann, Helmut H., Jr.

2004-09-01

This paper discusses a comprehensive vision for unmanned systems that will shape the future of Naval Warfare within a larger Joint Force concept, and examines the broad impact that can be anticipated across the Fleet. The vision has been articulated from a Naval perspective in NAVSEA technical report CSS/TR-01/09, Shaping the Future of Naval Warfare with Unmanned Systems, and from a Joint perspective in USJFCOM Rapid Assessment Process (RAP) Report #03-10 (Unmanned Effects (UFX): Taking the Human Out of the Loop). Here, the authors build on this foundation by reviewing the major findings and laying out the roadmap for achieving the vision and truly transforming how we fight wars. The focus is on broad impact across the Fleet - but the implications reach across all Joint forces. The term "Unmanned System" means different things to different people. Most think of vehicles that are remotely teleoperated that perform tasks under remote human control. Actually, unmanned systems are stand-alone systems that can execute missions and tasks without direct physical manned presence under varying levels of human control - from teleoperation to full autonomy. It is important to note that an unmanned system comprises a lot more than just a vehicle - it includes payloads, command and control, and communications and information processing.

Development of polarization-controlled multi-pass Thomson scattering system in the GAMMA 10 tandem mirror

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

Yoshikawa, M.; Morimoto, M.; Shima, Y.

2012-10-15

In the GAMMA 10 tandem mirror, the typical electron density is comparable to that of the peripheral plasma of torus-type fusion devices. Therefore, an effective method to increase Thomson scattering (TS) signals is required in order to improve signal quality. In GAMMA 10, the yttrium-aluminum-garnet (YAG)-TS system comprises a laser, incident optics, light collection optics, signal detection electronics, and a data recording system. We have been developing a multi-pass TS method for a polarization-based system based on the GAMMA 10 YAG TS. To evaluate the effectiveness of the polarization-based configuration, the multi-pass system was installed in the GAMMA 10 YAG-TSmore » system, which is capable of double-pass scattering. We carried out a Rayleigh scattering experiment and applied this double-pass scattering system to the GAMMA 10 plasma. The integrated scattering signal was made about twice as large by the double-pass system.« less

A clamping force measurement system for monitoring the condition of bolted joints on railway track joints and points

NASA Astrophysics Data System (ADS)

Tesfa, B.; Horler, G.; Thobiani, F. Al; Gu, F.; Ball, A. D.

2012-05-01

Many industrial structures associated with railway infrastructures rely on a large number of bolted joint connections to ensure safe and reliable operation of the track and trackside furniture. Significant sums of money are spent annually to repair the damage caused by bolt failures and to maintain the integrity of bolted structures. In the UK, Network Rail (the organization responsible for rail network maintenance and safety) conducts corrective and preventive maintenance manually on 26,000 sets of points (each having approximately 30 bolted joints per set), in order to ensure operational success and safety for the travelling public. Such manual maintenance is costly, disruptive, unreliable and prone to human error. The aim of this work is to provide a means of automatically measuring the clamping force of each individual bolted joint, by means of an instrumented washer. This paper describes the development of a sensor means to be used in the washer, which satisfies the following criteria. Sense changes in the clamping force of the joint and report this fact. Provide compatibility with the large dynamic range of clamping force. Satisfy the limitations in terms of physical size. Provide the means to electronically interface with the washer. Provide a means of powering the washer in situ. Provide a solution at an acceptable cost. Specifically the paper focuses on requirements 1, 2 and 3 and presents the results that support further development of the proposed design and the realization of a pre-prototype system. In the paper, various options for the force sensing element (strain gage, capacitor, piezo-resistive) have been compared, using design optimization techniques. As a result of the evaluation, piezo-resistive sensors in concert with a proprietary force attenuation method, have been found to offer the best performance and cost trade-off The performance of the novel clamping force sensor has been evaluated experimentally and the results show that a smart washer

Use of polarization to improve signal to clutter ratio in an outdoor active imaging system

NASA Astrophysics Data System (ADS)

Fontoura, Patrick F.; Giles, Michael K.; Padilla, Denise D.

2005-08-01

This paper describes the methodology and presents the results of the design of a polarization-sensitive system used to increase the signal-to-clutter ratio in a robust outdoor structured lighting sensor that uses standard CCD camera technology. This lighting sensor is intended to be used on an autonomous vehicle, looking down to the ground and horizontal to obstacles in an 8 foot range. The kinds of surfaces to be imaged are natural and man-made, such as asphalt, concrete, dirt and grass. The main problem for an outdoor eye-safe laser imaging system is that the reflected energy from background clutter tends to be brighter than the reflected laser energy. A narrow-band optical filter does not reduce significantly the background clutter in bright sunlight, and problems also occur when the surface is highly absorptive, like asphalt. Therefore, most of applications are limited to indoor and controlled outdoor conditions. A series of measurements was made for each of the materials studied in order to find the best configuration for the polarizing system and also to find out the potential improvement in the signal-to-clutter ratio (STC). This process was divided into three parts: characterization of the reflected sunlight, characterization of the reflected laser light, and measurement of the improvement in the STC. The results show that by using polarization properties it is possible to design an optical system that is able to increase the signal-to-clutter ratio from approximately 30% to 100% in the imaging system, depending on the kind of surface and on the incidence angle of the sunlight. The technique was also analyzed for indoor use, with the background clutter being the room illumination. For this specific case, polarization did not improve the signal-to-clutter ratio.

Reduced-rank technique for joint channel estimation in TD-SCDMA systems

NASA Astrophysics Data System (ADS)

Kamil Marzook, Ali; Ismail, Alyani; Mohd Ali, Borhanuddin; Sali, Adawati; Khatun, Sabira

2013-02-01

In time division-synchronous code division multiple access systems, increasing the system capacity by exploiting the inserting of the largest number of users in one time slot (TS) requires adding more estimation processes to estimate the joint channel matrix for the whole system. The increase in the number of channel parameters due the increase in the number of users in one TS directly affects the precision of the estimator's performance. This article presents a novel channel estimation with low complexity, which relies on reducing the rank order of the total channel matrix H. The proposed method exploits the rank deficiency of H to reduce the number of parameters that characterise this matrix. The adopted reduced-rank technique is based on truncated singular value decomposition algorithm. The algorithms for reduced-rank joint channel estimation (JCE) are derived and compared against traditional full-rank JCEs: least squares (LS) or Steiner and enhanced (LS or MMSE) algorithms. Simulation results of the normalised mean square error showed the superiority of reduced-rank estimators. In addition, the channel impulse responses founded by reduced-rank estimator for all active users offers considerable performance improvement over the conventional estimator along the channel window length.

Quantum and classical noise in practical quantum-cryptography systems based on polarization-entangled photons

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

Castelletto, S.; Degiovanni, I.P.; Rastello, M.L.

2003-02-01

Quantum-cryptography key distribution (QCKD) experiments have been recently reported using polarization-entangled photons. However, in any practical realization, quantum systems suffer from either unwanted or induced interactions with the environment and the quantum measurement system, showing up as quantum and, ultimately, statistical noise. In this paper, we investigate how an ideal polarization entanglement in spontaneous parametric down-conversion (SPDC) suffers quantum noise in its practical implementation as a secure quantum system, yielding errors in the transmitted bit sequence. Since all SPDC-based QCKD schemes rely on the measurement of coincidence to assert the bit transmission between the two parties, we bundle up themore » overall quantum and statistical noise in an exhaustive model to calculate the accidental coincidences. This model predicts the quantum-bit error rate and the sifted key and allows comparisons between different security criteria of the hitherto proposed QCKD protocols, resulting in an objective assessment of performances and advantages of different systems.« less

Creating Two-Dimensional Electron Gas in Polar/Polar Perovskite Oxide Heterostructures: First-Principles Characterization of LaAlO3/A(+)B(5+)O3.

PubMed

Wang, Yaqin; Tang, Wu; Cheng, Jianli; Behtash, Maziar; Yang, Kesong

2016-06-01

By using first-principles electronic structure calculations, we explored the possibility of producing two-dimensional electron gas (2DEG) at the polar/polar (LaO)(+)/(BO2)(+) interface in the LaAlO3/A(+)B(5+)O3 (A = Na and K, B = Nb and Ta) heterostructures (HS). Unlike the prototype polar/nonpolar LaAlO3/SrTiO3 HS system where there exists a least film thickness of four LaAlO3 unit cells to have an insulator-to-metal transition, we found that the polar/polar LaAlO3/A(+)B(5+)O3 HS systems are intrinsically conducting at their interfaces without an insulator-to-metal transition. The interfacial charge carrier densities of these polar/polar HS systems are on the order of 10(14) cm(-2), much larger than that of the LaAlO3/SrTiO3 system. This is mainly attributed to two donor layers, i.e., (LaO)(+) and (BO2)(+) (B = Nb and Ta), in the polar/polar LaAlO3/A(+)B(5+)O3 systems, while only one (LaO)(+) donor layer in the polar/nonpolar LaAlO3/SrTiO3 system. In addition, it is expected that, due to less localized Nb 4d and Ta 5d orbitals with respect to Ti 3d orbitals, these LaAlO3/A(+)B(5+)O3 HS systems can exhibit potentially higher electron mobility because of their smaller electron effective mass than that in the LaAlO3/SrTiO3 system. Our results demonstrate that the electronic reconstruction at the polar/polar interface could be an alternative way to produce superior 2DEG in the perovskite-oxide-based HS systems.

Fiber-based polarization-sensitive Mueller matrix optical coherence tomography with continuous source polarization modulation.

PubMed

Jiao, Shuliang; Todorović, Milos; Stoica, George; Wang, Lihong V

2005-09-10

We report on a new configuration of fiber-based polarization-sensitive Mueller matrix optical coherence tomography that permits the acquisition of the round-trip Jones matrix of a biological sample using only one light source and a single depth scan. In this new configuration, a polarization modulator is used in the source arm to continuously modulate the incident polarization state for both the reference and the sample arms. The Jones matrix of the sample can be calculated from the two frequency terms in the two detection channels. The first term is modulated by the carrier frequency, which is determined by the longitudinal scanning mechanism, whereas the other term is modulated by the beat frequency between the carrier frequency and the second harmonic of the modulation frequency of the polarization modulator. One important feature of this system is that, for the first time to our knowledge, the Jones matrix of the sample can be calculated with a single detection channel and a single measurement when diattenuation is negligible. The system was successfully tested by imaging both standard polarization elements and biological samples.

A Model for a Single Unmanned Aircraft Systems (UAS) Program Office Managing Joint ISR Capabilities

DTIC Science & Technology

2017-10-01

reduction in manning from the multiple program office structure to the new single program management model. Additional information regarding this...OFFICE MANAGING JOINT ISR CAPABILITIES by Angela E. Burris A Research Report Submitted to the Faculty In Partial Fulfillment of...research paper is to answer how a single management office could provide greater agility for unmanned aircraft systems (UAS); supporting Joint concepts

Polarization tracking system for free-space optical communication, including quantum communication

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

Nordholt, Jane Elizabeth; Newell, Raymond Thorson; Peterson, Charles Glen

Quantum communication transmitters include beacon lasers that transmit a beacon optical signal in a predetermined state of polarization such as one of the states of polarization of a quantum communication basis. Changes in the beacon polarization are detected at a receiver, and a retarder is adjusted so that the states of polarization in a received quantum communication optical signal are matched to basis polarizations. The beacon and QC signals can be at different wavelengths so that the beacon does not interfere with detection and decoding of the QC optical signal.

Joint image encryption and compression scheme based on a new hyperchaotic system and curvelet transform

NASA Astrophysics Data System (ADS)

Zhang, Miao; Tong, Xiaojun

2017-07-01

This paper proposes a joint image encryption and compression scheme based on a new hyperchaotic system and curvelet transform. A new five-dimensional hyperchaotic system based on the Rabinovich system is presented. By means of the proposed hyperchaotic system, a new pseudorandom key stream generator is constructed. The algorithm adopts diffusion and confusion structure to perform encryption, which is based on the key stream generator and the proposed hyperchaotic system. The key sequence used for image encryption is relation to plain text. By means of the second generation curvelet transform, run-length coding, and Huffman coding, the image data are compressed. The joint operation of compression and encryption in a single process is performed. The security test results indicate the proposed methods have high security and good compression effect.

An all-reflective polarization rotator

NASA Astrophysics Data System (ADS)

Bohus, J.; Budai, Judit; Kalashnikov, M.; Osvay, K.

2017-05-01

The conceptual design and proof of principle experimental results of a polarization rotator based on mirrors are presented. The device is suitable for any-angle, online rotation of the plane of polarization of high peak intensity ultrashort laser pulses. Controllable rotation of the polarization vector of short laser pulses with a broad bandwidth requires achromatic retarding plates which have a limited scalability and the substantial plate thickness can lead to pulse broadening and inaccurate polarization rotation. Polarization rotators based on reflective optical elements are preferable alternatives to wave plates especially when used in high average power or high peak intensity ultra-short laser systems. The control of the polarization state is desirable in many laser-matter interaction experiments e.g., high harmonic and attosecond pulse generation, electron, proton and ion acceleration, electron-positron pair creating, vacuum nonlinear polarization effect. The device can also serve as a beam attenuator, in combination with a linear polarizer.

Manipulation of polarization anisotropy in bare InAs and InAs/GaSb core-shell nanowires

NASA Astrophysics Data System (ADS)

Patra, Atanu; Roy, Anushree; Gomes, Umesh Prasad; Zannier, Valentina; Ercolani, Daniele; Sorba, Lucia

2018-04-01

In this article, we compare the excitation wavelength dependence of the polarization anisotropy (ρ) of an internal field induced Raman scattering signal in individual bare InAs and InAs/GaSb core-shell nanowires. The measured value of ρ of the Raman scattering intensity for InAs/GaSb core-shell nanowires has a minimum at ˜500 nm, while for the bare InAs nanowire, the value of ρ monotonically increases over the same range of wavelengths. We have modeled the scattering intensities of both systems by considering the joint role of Raman tensor components and confinement of electromagnetic radiation inside the nanowire at two orthogonal polarization configurations of the electromagnetic radiation. The theoretical results allow us to understand that the observed behavior of ρ is related to the nanowire geometry and to the difference in the wavelength dependence of the dielectric constants of InAs and GaSb. This work shows the possibility of manipulating the polarization anisotropy by selecting suitable diameters and materials for the core and the shell of the nanowire. We also report a six-fold increase in Raman scattering intensity due to the GaSb shell on InAs nanowires.

Nonlinear optical cryptosystem based on joint Fresnel transform correlator under vector wave illumination

NASA Astrophysics Data System (ADS)

Xueju, Shen; Chao, Lin; Xiao, Zou; Jianjun, Cai

2015-05-01

We present a nonlinear optical cryptosystem with multi-dimensional keys including phase, polarization and diffraction distance. To make full use of the degrees of freedom that optical processing offers, an elaborately designed vector wave with both a space-variant phase and locally linear polarization is generated with a common-path interferometer for illumination. The joint transform correlator in the Fresnel domain, implemented with a double optical wedge, is utilized as the encryption framework which provides an additional key known as the Fresnel diffraction distance. Two nonlinear operations imposed on the recorded joint Fresnel power distribution (JFPD) by a charge coupled device (CCD) are adopted. The first one is the division of power distribution of the reference window random function which is previously proposed by researchers and can improve the quality of the decrypted image. The second one is the recording of a hybrid JFPD using a micro-polarizers array with orthogonal and random transmissive axes attached to the CCD. Then the hybrid JFPD is further scrambled by substituting random noise for partial power distribution. The two nonlinear operations break the linearity of this cryptosystem and provide ultra security. We verify our proposal using a quick response code for noise-free recovery.

Polar transport in plants mediated by membrane transporters: focus on mechanisms of polar auxin transport.

PubMed

Naramoto, Satoshi

2017-12-01

Directional cell-to-cell transport of functional molecules, called polar transport, enables plants to sense and respond to developmental and environmental signals. Transporters that localize to plasma membranes (PMs) in a polar manner are key components of these systems. PIN-FORMED (PIN) auxin efflux carriers, which are the most studied polar-localized PM proteins, are implicated in the polar transport of auxin that in turn regulates plant development and tropic growth. In this review, the regulatory mechanisms underlying polar localization of PINs, control of auxin efflux activity, and PIN abundance at PMs are considered. Up to date information on polar-localized nutrient transporters that regulate directional nutrient movement from soil into the root vasculature is also discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

A ROF transport system using phase & polarization modulation based on OFDM technique

NASA Astrophysics Data System (ADS)

Mallick, Khaleda; Patra, Ardhendu Sekhar

2018-05-01

A radio-over-fiber (ROF) transport system using phase and polarization modulator based on orthogonal frequency division multiplexing (OFDM) technique has been proposed and demonstrated, to transmit 2.5 Gbps at 7.5 GHz over 40 km single mode fiber (SMF). The transmission performance is observed by proper bit error rate and clear eye diagram. Our proposed system become a prominent alternative, as it has advantages of communication link for greater bandwidth and data rates.

Kinetic Framework for the Magnetosphere-Ionosphere-Plasmasphere-Polar Wind System: Modeling Ion Outflow

NASA Astrophysics Data System (ADS)

Schunk, R. W.; Barakat, A. R.; Eccles, V.; Karimabadi, H.; Omelchenko, Y.; Khazanov, G. V.; Glocer, A.; Kistler, L. M.

2014-12-01

A Kinetic Framework for the Magnetosphere-Ionosphere-Plasmasphere-Polar Wind System is being developed in order to provide a rigorous approach to modeling the interaction of hot and cold particle interactions. The framework will include ion and electron kinetic species in the ionosphere, plasmasphere and polar wind, and kinetic ion, super-thermal electron and fluid electron species in the magnetosphere. The framework is ideally suited to modeling ion outflow from the ionosphere and plasmasphere, where a wide range for fluid and kinetic processes are important. These include escaping ion interactions with (1) photoelectrons, (2) cusp/auroral waves, double layers, and field-aligned currents, (3) double layers in the polar cap due to the interaction of cold ionospheric and hot magnetospheric electrons, (4) counter-streaming ions, and (5) electromagnetic wave turbulence. The kinetic ion interactions are particularly strong during geomagnetic storms and substorms. The presentation will provide a brief description of the models involved and discuss the effect that kinetic processes have on the ion outflow.

Optical detection dental disease using polarized light

DOEpatents

Everett, Matthew J.; Colston, Jr., Billy W.; Sathyam, Ujwal S.; Da Silva, Luiz B.; Fried, Daniel

2003-01-01

A polarization sensitive optical imaging system is used to detect changes in polarization in dental tissues to aid the diagnosis of dental disease such as caries. The degree of depolarization is measured by illuminating the dental tissue with polarized light and measuring the polarization state of the backscattered light. The polarization state of this reflected light is analyzed using optical polarimetric imaging techniques. A hand-held fiber optic dental probe is used in vivo to direct the incident beam to the dental tissue and collect the reflected light. To provide depth-resolved characterization of the dental tissue, the polarization diagnostics may be incorporated into optical coherence domain reflectometry and optical coherence tomography (OCDR/OCT) systems, which enables identification of subsurface depolarization sites associated with demineralization of enamel or bone.

Development of a cross-polarization scattering system for the measurement of internal magnetic fluctuations in the DIII-D tokamak

DOE PAGES

Rhodes, Terry L.; Peebles, William A.; Crocker, Neal A.; ...

2014-08-05

The design and performance of a new cross-polarization scattering (CPS) system for the localized measurement of internal magnetic fluctuations is presented. CPS is a process whereby magnetic fluctuations scatter incident electromagnetic radiation into a perpendicular polarization which is subsequently detected. A new CPS design that incorporates a unique scattering geometry was laboratory tested, optimized, and installed on the DIII-D tokamak. Plasma tests of signal-to-noise, polarization purity, and frequency response indicate proper functioning of the system. Lastly, CPS data show interesting features related to internal MHD perturbations known as sawteeth that are not observed on density fluctuations.

Joint Inversion of Source Location and Source Mechanism of Induced Microseismics

NASA Astrophysics Data System (ADS)

Liang, C.

2014-12-01

Seismic source mechanism is a useful property to indicate the source physics and stress and strain distribution in regional, local and micro scales. In this study we jointly invert source mechanisms and locations for microseismics induced in fluid fracturing treatment in the oil and gas industry. For the events that are big enough to see waveforms, there are quite a few techniques can be applied to invert the source mechanism including waveform inversion, first polarity inversion and many other methods and variants based on these methods. However, for events that are too small to identify in seismic traces such as the microseismics induced by the fluid fracturing in the Oil and Gas industry, a source scanning algorithms (SSA for short) with waveform stacking are usually applied. At the same time, a joint inversion of location and source mechanism are possible but at a cost of high computation budget. The algorithm is thereby called Source Location and Mechanism Scanning Algorithm, SLMSA for short. In this case, for given velocity structure, all possible combinations of source locations (X,Y and Z) and source mechanism (Strike, Dip and Rake) are used to compute travel-times and polarities of waveforms. Correcting Normal moveout times and polarities, and stacking all waveforms, the (X, Y, Z , strike, dip, rake) combination that gives the strongest stacking waveform is identified as the solution. To solve the problem of high computation problem, CPU-GPU programing is applied. Numerical datasets are used to test the algorithm. The SLMSA has also been applied to a fluid fracturing datasets and reveal several advantages against the location only method: (1) for shear sources, the source only program can hardly locate them because of the canceling out of positive and negative polarized traces, but the SLMSA method can successfully pick up those events; (2) microseismic locations alone may not be enough to indicate the directionality of micro-fractures. The statistics of

Process for preparing organoclays for aqueous and polar-organic systems

DOEpatents

Chaiko, David J.

2001-01-01

A process for preparing organoclays as thixotropic agents to control the rheology of water-based paints and other aqueous and polar-organic systems. The process relates to treating low-grade clay ores to achieve highly purified organoclays and/or to incorporate surface modifying agents onto the clay by adsorption and/or to produce highly dispersed organoclays without excessive grinding or high shear dispersion. The process involves the treatment of impure, or run-of-mine, clay using an aqueous biphasic extraction system to produce a highly dispersed clay, free of mineral impurities and with modified surface properties brought about by adsorption of the water-soluble polymers used in generating the aqueous biphasic extraction system. This invention purifies the clay to greater than 95%.

Discrimination of portraits using a hybrid parallel joint transform correlator system

NASA Astrophysics Data System (ADS)

Inaba, Rieko; Hashimoto, Asako; Kodate, Kashiko

1999-05-01

A hybrid parallel joint transform correlation system is demonstrated through the introduction of a five-channel binary zone plate array and is applied to the discrimination of portraits for a presumed criminal investigation. In order to improve performance, we adopt pe-processing of images with white area of 20%. Furthermore, we discuss the robustness.

Space Station alpha joint bearing

NASA Technical Reports Server (NTRS)

Everman, Michael R.; Jones, P. Alan; Spencer, Porter A.

1987-01-01

Perhaps the most critical structural system aboard the Space Station is the Solar Alpha Rotary Joint which helps align the power generation system with the sun. The joint must provide structural support and controlled rotation to the outboard transverse booms as well as power and data transfer across the joint. The Solar Alpha Rotary Joint is composed of two transition sections and an integral, large diameter bearing. Alpha joint bearing design presents a particularly interesting problem because of its large size and need for high reliability, stiffness, and on orbit maintability. The discrete roller bearing developed is a novel refinement to cam follower technology. It offers thermal compensation and ease of on-orbit maintenance that are not found in conventional rolling element bearings. How the bearing design evolved is summarized. Driving requirements are reviewed, alternative concepts assessed, and the selected design is described.

The effect of brazing parameters on corrosion behavior of brazed aluminum joints

NASA Astrophysics Data System (ADS)

Ghasimakbari, Farzam; Hadian, Ali Mohammad; Ershadrad, Soheil; Omidazad, Amir Mansour

2018-01-01

Fluid transmission pipes made of aluminum are widely used in petrochemical industries. For many applications, they have to be brazed to each other. The brazed joints, in many cases, are encountered with corrosive medias. This paper reports a part of a work to investigate the corrosion behavior of brazed AA6061 using AA4047 as filler metal with and without the use of flux under different brazing atmospheres. The samples brazed under air, vacuum, argon, and hydrogen atmospheres. The interfacial area of the joints was examined to ensure being free of any defects. The sides of each test piece were covered with an insulator and the surface of the joint was encountered to polarization test. The results revealed a significant difference of corrosion resistance. The samples that brazed under argon and hydrogen atmospheres had better corrosion resistance than other samples. The microstructure of the corroded joints revealed that the presence of defects, impurities due to use of flux and depth of filter metal penetration in base metal are crucial variables on the corrosion resistance of the joints.

Enhanced Compton Backscattering in a Periodic Mirror System for Polarized Positron Beam Generation

NASA Astrophysics Data System (ADS)

Miyahara, Yoshikazu

2002-05-01

By colliding a circularly polarized high power laser beam with a high-energy electron beam, intense circularly polarized γ-rays can be generated, which in turn can be used to produce a longitudinally polarized positron beam for a linear collider. In the present paper, an optical mirror system with periodic focal points is considered to generate intense polarized γ-rays. A CO2 laser beam propagates back and forth in a series of holed mirrors in a straight line. The diffraction loss through the holes is negligibly small, so that the laser beam can be used repeatedly for the collision. The beam size is reduced to 22 μm at a minimum and kept the same in 20 unit cells, ten of which are combined in series. A 5.8 GeV electron beam is focused to 30 μm at a minimum in a series of triplets of permanent quadrupole magnets to generate γ-rays of 60 MeV at a maximum. A γ-ray yield required for a positron beam in a linear collider can be obtained by 10 laser sources with a power of 3.1 kW each, which is considerably lower than the total power assumed in a previous proposal.

Proposal for research and education: joint lectures and practicals on central nervous system anatomy and physiology.

PubMed

Kageyama, Ikuo; Yoshimura, Ken; Satoh, Yoshihide; Nanayakkara, Chinthani D; Pallegama, Ranjith W; Iwasaki, Shin-Ichi

2016-07-01

We coordinated anatomy and physiology lectures and practicals to facilitate an integrated understanding of morphology and function in a basic medical science program for dental students and to reduce the time spent on basic science education. This method is a means to provide the essential information and skills in less time. The overall impression was that the practice of joint central nervous system lectures and practicals was an efficient method for students, which suggests that joint lectures might also be useful for clinical subjects. About two-thirds of students felt that the joint anatomy and physiology lecture on the central nervous system was useful and necessary in understanding the relationship between morphology and function, at least for this subject. One-third of students were neutral on the effectiveness of this method. However, the survey results suggest that improvements are needed in the method and timing of joint lectures and practicals. The present teaching approach can be further improved by conducting combined lectures in which the form and function of anatomic structures are presented by the relevant departments during the same lecture. Finally, joint lecturers and practicals offer an opportunity to increase student understanding of the importance of new research findings by the present authors and other researchers.

Quantifying climate feedbacks in polar regions.

PubMed

Goosse, Hugues; Kay, Jennifer E; Armour, Kyle C; Bodas-Salcedo, Alejandro; Chepfer, Helene; Docquier, David; Jonko, Alexandra; Kushner, Paul J; Lecomte, Olivier; Massonnet, François; Park, Hyo-Seok; Pithan, Felix; Svensson, Gunilla; Vancoppenolle, Martin

2018-05-15

The concept of feedback is key in assessing whether a perturbation to a system is amplified or damped by mechanisms internal to the system. In polar regions, climate dynamics are controlled by both radiative and non-radiative interactions between the atmosphere, ocean, sea ice, ice sheets and land surfaces. Precisely quantifying polar feedbacks is required for a process-oriented evaluation of climate models, a clear understanding of the processes responsible for polar climate changes, and a reduction in uncertainty associated with model projections. This quantification can be performed using a simple and consistent approach that is valid for a wide range of feedbacks, offering the opportunity for more systematic feedback analyses and a better understanding of polar climate changes.

Diagnostic efficiency of Mueller-matrix polarization reconstruction system of the phase structure of liver tissue

NASA Astrophysics Data System (ADS)

Zabolotna, Natalia I.; Pavlov, Sergii V.; Radchenko, Kostiantyn O.; Stasenko, Vladyslav A.; Wójcik, Waldemar; Kussambayeva, Nazym

2015-12-01

The application field of using the Mueller-matrix polarizing reconstruction system of phase structure of biological layer for optical-anisotropic parameters differentiation of histological sections of healthy and rat's liver with hepatitis were investigated. Comparison of system informativity with known systems on indexes of sensitivity, specificity and balanced accuracy were performed.

Seeing the Night in a New Light—VIIRS Day/Night Band Capabilities and Prospects for a Joint Suomi/JPSS-1 Observing System

NASA Astrophysics Data System (ADS)

Solbrig, J. E.; Miller, S. D.; Straka, W. C.; Seaman, C.; Combs, C.; Heidinger, A.; Walther, A.

2017-12-01

The Day/Night Band (DNB), a special sensor on board the Visible/Infrared Imaging Radiometer Suite (VIIRS) devoted to low-light visible imaging, has representated a kind of `disruptive technology' in terms of how we observe the nocturnal environment. Since its debut on the Suomi National Polar-orbiting Partnership (NPP), launched in Fall 2011, the DNB has solidified its claim to fame as the most novel addition to the National Oceanic and Atmospheric Administration's future polar-oribitng program, represented by the Joint Polar Satellite System (JPSS). The first member of which (JPSS-1) is scheduled to launch in Fall of 2017, joining Suomi in its 1330 local time ascending node orbit. JPSS-1 will be displaced by ½ orbit ahead of Suomi, providing roughly 50 min between overpasses. Importantly, JPSS-1 will provide a second DNB observation, enabling the first time-resolved measurements of low-light visible at low and mid-latitudes from this new sensor technology. The DNB provides unprecedented capability to leverage light emissions from natural and artificial nocturnal sources, ranging from moonlight and city lights, ships, fires, lightning flashes, and even atmospheric nightglow. The calibrated DNB observations enable use of moonlight in similar way to daytime visible, allowing for quantitative description of cloud and aerosol optical properties. This presentation updates the community on DNB-related research initiatives. Statistics based on a multi-year collection of data at Salar de Uyuni, Bolivia and White Sands, New Mexico lend confidence to the performance of a lunar irradiance model used to enable nighttime optical property retrievals. Selected examples of notable events, including the devastating Portugal wildfires, emergence of the massive rift in the Larsen C ice shelf, and examples from the growing compilation of atmospheric gravity waves in nightglow, will also be highlighted.

Alloplastic temporomandibular joint replacement systems: a systematic review of their history.

PubMed

De Meurechy, N; Mommaerts, M Y

2018-06-01

This systematic review provides an overview of the historical evolution of the prosthetic temporomandibular joint and addresses the challenges and complications faced by engineers and surgeons, in an effort to shed light on why only a few systems remain available. A better understanding of the history of temporomandibular joint prostheses might also provide insights into the origin of the negative public opinion of the prosthesis, which is based on outdated information. A computerized search using the PubMed Central, ScienceDirect, Wiley Online, Ovid, and Cochrane Library databases was performed following the PRISMA guidelines. Out of 7122 articles identified, 41 met the inclusion criteria for this systematic review. Although several historical reviews have been published previously, none has covered such an extensive time period or has described all designs. Furthermore, besides providing a historical overview, this review discusses the rationale behind the evolution in design and biomaterials, which have largely contributed to the outcomes of the prosthetic systems. Copyright © 2018 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Calibration of the degree of linear polarization measurements of the polarized Sun-sky radiometer based on the POLBOX system.

PubMed

Li, Zhengqiang; Li, Kaitao; Li, Li; Xu, Hua; Xie, Yisong; Ma, Yan; Li, Donghui; Goloub, Philippe; Yuan, Yinlin; Zheng, Xiaobing

2018-02-10

Polarization observation of sky radiation is the frontier approach to improve the remote sensing of atmospheric components, e.g., aerosol and clouds. The polarization calibration of the ground-based Sun-sky radiometer is the basis for obtaining accurate degree of linear polarization (DOLP) measurement. In this paper, a DOLP calibration method based on a laboratory polarized light source (POLBOX) is introduced in detail. Combined with the CE318-DP Sun-sky polarized radiometer, a calibration scheme for DOLP measurement is established for the spectral range of 440-1640 nm. Based on the calibration results of the Sun-sky radiometer observation network, the polarization calibration coefficient and the DOLP calibration residual are analyzed statistically. The results show that the DOLP residual of the calibration scheme is about 0.0012, and thus it can be estimated that the final DOLP calibration accuracy of this method is about 0.005. Finally, it is verified that the accuracy of the calibration results is in accordance with the expected results by comparing the simulated DOLP with the vector radiative transfer calculations.

Dichotomous versus semi-quantitative scoring of ultrasound joint inflammation in rheumatoid arthritis using novel individualized joint selection methods.

PubMed

Tan, York Kiat; Allen, John C; Lye, Weng Kit; Conaghan, Philip G; Chew, Li-Ching; Thumboo, Julian

2017-05-01

The aim of the study is to compare the responsiveness of two joint inflammation scoring systems (dichotomous scoring (DS) versus semi-quantitative scoring (SQS)) using novel individualized ultrasound joint selection methods and existing ultrasound joint selection methods. Responsiveness measured by the standardized response means (SRMs) using the DS and the SQS system (for both the novel and existing ultrasound joint selection methods) was derived using the baseline and the 3-month total inflammatory scores from 20 rheumatoid arthritis patients. The relative SRM gain ratios (SRM-Gains) for both scoring system (DS and SQS) comparing the novel to the existing methods were computed. Both scoring systems (DS and SQS) demonstrated substantial SRM-Gains (ranged from 3.31 to 5.67 for the DS system and ranged from 1.82 to 3.26 for the SQS system). The SRMs using the novel methods ranged from 0.94 to 1.36 for the DS system and ranged from 0.89 to 1.11 for the SQS system. The SRMs using the existing methods ranged from 0.24 to 0.32 for the DS system and ranged from 0.34 to 0.49 for the SQS system. The DS system appears to achieve high responsiveness comparable to SQS for the novel individualized ultrasound joint selection methods.

Scaling of the polarization amplitude in quantum many-body systems in one dimension

NASA Astrophysics Data System (ADS)

Kobayashi, Ryohei; Nakagawa, Yuya O.; Fukusumi, Yoshiki; Oshikawa, Masaki

2018-04-01

Resta proposed a definition of the electric polarization in one-dimensional systems in terms of the ground-state expectation value of the large gauge transformation operator. Vanishing of the expectation value in the thermodynamic limit implies that the system is a conductor. We study Resta's polarization amplitude (expectation value) in the S =1 /2 XXZ chain and its several generalizations, in the gapless conducting Tomonaga-Luttinger liquid phase. We obtain an analytical expression in the lowest-order perturbation theory about the free fermion point (XY chain) and an exact result for the Haldane-Shastry model with long-range interactions. We also obtain numerical results, mostly using the exact diagonalization method. We find that the amplitude exhibits a power-law scaling in the system size (chain length) and vanishes in the thermodynamic limit. On the other hand, the exponent depends on the model even when the low-energy limit is described by the Tomonaga-Luttinger liquid with the same Luttinger parameter. We find that a change in the exponent occurs when the Umklapp term(s) are eliminated, suggesting the importance of the Umklapp terms.

Wireless wearable range-of-motion sensor system for upper and lower extremity joints: a validation study.

PubMed

Kumar, Yogaprakash; Yen, Shih-Cheng; Tay, Arthur; Lee, Wangwei; Gao, Fan; Zhao, Ziyi; Li, Jingze; Hon, Benjamin; Tian-Ma Xu, Tim; Cheong, Angela; Koh, Karen; Ng, Yee-Sien; Chew, Effie; Koh, Gerald

2015-02-01

Range-of-motion (ROM) assessment is a critical assessment tool during the rehabilitation process. The conventional approach uses the goniometer which remains the most reliable instrument but it is usually time-consuming and subject to both intra- and inter-therapist measurement errors. An automated wireless wearable sensor system for the measurement of ROM has previously been developed by the current authors. Presented is the correlation and accuracy of the automated wireless wearable sensor system against a goniometer in measuring ROM in the major joints of upper (UEs) and lower extremities (LEs) in 19 healthy subjects and 20 newly disabled inpatients through intra (same) subject comparison of ROM assessments between the sensor system against goniometer measurements by physical therapists. In healthy subjects, ROM measurements using the new sensor system were highly correlated with goniometry, with 95% of differences < 20° and 10° for most movements in major joints of UE and LE, respectively. Among inpatients undergoing rehabilitation, ROM measurements using the new sensor system were also highly correlated with goniometry, with 95% of the differences being < 20° and 25° for most movements in the major joints of UE and LE, respectively.

Correlation between muscle structure and filter characteristics of the muscle-joint system in three orthopteran insect species

PubMed

BÄSsler; BÜSchges; Meditz; BÄSsler

1996-01-01

In orthopteran insects, neural networks for joint control exhibit different characteristics due to behavioural specializations. We investigated whether these differences are generated purely by the neuronal networks, or whether characteristics of the muscles or joint architecture (muscle­joint system) are also involved in these behavioural specializations. We compared the properties of the muscle system moving the femur­tibia joint of the middle and hindleg of three species, Carausius morosus, Cuniculina impigra and Locusta migratoria. Four aspects were analysed for the tibial extensor muscle: (i) the frequency-dependence of motoneuronal activity in response to sinusoidal stimulation of the femoral chordotonal organ (fCO), (ii) the muscle structure, (iii) the innervation pattern of the muscle and (iv) the histochemical properties of the muscle fibres. These aspects were compared with the filter characteristics of the open-loop femur­tibia control system and of the muscle­joint system involved. Whereas in both phasmid species (Carausius morosus and Cuniculina impigra) the motoneuronal activity steadily increases with sinusoidal stimulation of the fCO in the frequency range 0.01­5 Hz, in Locusta migratoria there is a decrease in motoneuronal activity between 0.01 and 0.3 Hz. The muscle structure is basically similar in all three species, as the number of singly innervated muscle fibres (supplied by the fast extensor tibiae motor neurone, FETi) decreases from proximal to distal. The number of triply innervated fibres supplied by the FETi, the slow extensor tibiae (SETi) and the common inhibitor 1 (CI1) is maximal in the middle of the muscle, and the number of dually innervated fibres (supplied by SETi, CI1) increases from proximal to distal. Differences between the locust and the two phasmid species exist in the distal portion of the muscle. The phasmid extensor tibiae muscle contains a morphologically distinct bundle of muscle fibres, not present

Exciplex fluorescence emission from simple organic intramolecular constructs in non-polar and highly polar media as model systems for DNA-assembled exciplex detectors.

PubMed

Bichenkova, Elena V; Sardarian, Ali R; Wilton, Amanda N; Bonnet, Pascal; Bryce, Richard A; Douglas, Kenneth T

2006-01-21

Organic intramolecular exciplexes, N-(4-dimethylaminobenzyl)-N-(1-pyrenemethyl)amine (1) and N'-4-dimethylaminonaphthyl-N-(1-pyrenemethyl)amine (2), were used as model systems to reveal major factors affecting their exciplex fluorescence, and thus lay the basis for developing emissive target-assembled exciplexes for DNA-mounted systems in solution. These models with an aromatic pyrenyl hydrocarbon moiety as an electron acceptor appropriately connected to an aromatic dimethylamino electron donor component (N,N-dimethylaminophenyl or N,N-dimethylaminonaphthyl) showed strong intramolecular exciplex emission in both non-polar and highly polar solvents. The effect of dielectric constant on the maximum wavelength for exciplex emission was studied, and emission was observed for 1 and 2 over the full range of solvent from non-polar hydrocarbons up to N-methylformamide with a dielectric constant of 182. Quantum yields were determined for these intramolecular exciplexes in a range of solvents relative to that for Hoechst 33,258. Conformational analysis of 1 was performed both computationally and via qualitative 2D NMR using (1)H-NOESY experiments. The results obtained indicated the contribution of pre-folded conformation(s) to the ground state of 1 conducive to exciplex emission. This research provides the initial background for design of self-assembled, DNA-mounted exciplexes and underpins further development of exciplex-based hybridisation bioassays.

Depth-encoded all-fiber swept source polarization sensitive OCT

PubMed Central

Wang, Zhao; Lee, Hsiang-Chieh; Ahsen, Osman Oguz; Lee, ByungKun; Choi, WooJhon; Potsaid, Benjamin; Liu, Jonathan; Jayaraman, Vijaysekhar; Cable, Alex; Kraus, Martin F.; Liang, Kaicheng; Hornegger, Joachim; Fujimoto, James G.

2014-01-01

Polarization sensitive optical coherence tomography (PS-OCT) is a functional extension of conventional OCT and can assess depth-resolved tissue birefringence in addition to intensity. Most existing PS-OCT systems are relatively complex and their clinical translation remains difficult. We present a simple and robust all-fiber PS-OCT system based on swept source technology and polarization depth-encoding. Polarization multiplexing was achieved using a polarization maintaining fiber. Polarization sensitive signals were detected using fiber based polarization beam splitters and polarization controllers were used to remove the polarization ambiguity. A simplified post-processing algorithm was proposed for speckle noise reduction relaxing the demand for phase stability. We demonstrated systems design for both ophthalmic and catheter-based PS-OCT. For ophthalmic imaging, we used an optical clock frequency doubling method to extend the imaging range of a commercially available short cavity light source to improve polarization depth-encoding. For catheter based imaging, we demonstrated 200 kHz PS-OCT imaging using a MEMS-tunable vertical cavity surface emitting laser (VCSEL) and a high speed micromotor imaging catheter. The system was demonstrated in human retina, finger and lip imaging, as well as ex vivo swine esophagus and cardiovascular imaging. The all-fiber PS-OCT is easier to implement and maintain compared to previous PS-OCT systems and can be more easily translated to clinical applications due to its robust design. PMID:25401008

Optimum design of Geodesic dome’s jointing system

NASA Astrophysics Data System (ADS)

Tran, Huy. T.

2018-04-01

This study attempts to create a new design for joint connector of Geodesic dome. A new type of joint connector design is proposed for flexible rotating connection; comparing it to another, this design is cheaper and workable. After calculating the bearing capacity of the sample according to EC3 and Vietnam standard TCVN 5575-2012, FEM model of the design sample is carried out in many specific situation to consider the stress distribution, the deformation, the local destruction… in the connector. The analytical results and the FE data are consistent. The FE analysis also points out the behavior of some details that simple calculation cannot show. Hence, we can choose the optimum design of joint connector.

THE KEY ROLE OF SOLAR DYNAMICS IN THE CHROMOSPHERIC HANLE POLARIZATION

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

Carlin, E. S.; Bianda, M., E-mail: escarlin@irsol.ch

The quantum theory of polarized light allows one to model scattering in the solar atmosphere for inferring its properties. This powerful approach has revealed two key long-standing problems in solar physics: the puzzling dilemmas between theory and observations in several anomalously polarized spectral lines and the need for inferring the ubiquitous weak chromospheric magnetic fields, which requires discriminating the Hanle effect in dynamic optically thick plasmas. However, the ever-present dynamics, i.e., the temporal evolution of heatings and macroscopic motions, has been widely disregarded when modeling and interpreting the scattering polarization. This has hindered a consistent theoretical solution to the puzzlemore » while falsifying the Hanle diagnosis. Here, we show that the dynamical evolution is a keystone for solving both problems because its systematic impact allows an explanation of the observations from “anomalous” instantaneous polarization signals. Evolution accounted for, we reproduce amplitudes and (spectral and spatial) shapes of the Ca i 4227 Å polarization at solar disk center, identifying a restrictive arrangement of magnetic fields, kinematics, heatings, and spatio-temporal resolution. We find that the joint action of dynamics, Hanle effect, and low temporal resolutions mimics Zeeman linear polarization profiles, the true weak-field Zeeman signals being negligible. Our results allow reinterpretation of many polarization signals of the solar spectra and support time-dependent scattering polarization as a powerful tool for deciphering the spatio-temporal distribution of chromospheric heatings and fields. This approach may be a key aid in developing the Hanle diagnosis for the solar atmosphere.« less

Polarization-sensitive optical coherence tomography measurements with different phase modulation amplitude when using continuous polarization modulation

NASA Astrophysics Data System (ADS)

Lu, Zenghai; Kasaragod, Deepa K.; Matcher, Stephen J.

2012-01-01

We demonstrate theoretically and experimentally that the phase retardance and relative optic-axis orientation of a sample can be calculated without prior knowledge of the actual value of the phase modulation amplitude when using a polarization-sensitive optical coherence tomography system based on continuous polarization modulation (CPM-PS-OCT). We also demonstrate that the sample Jones matrix can be calculated at any values of the phase modulation amplitude in a reasonable range depending on the system effective signal-to-noise ratio. This has fundamental importance for the development of clinical systems by simplifying the polarization modulator drive instrumentation and eliminating its calibration procedure. This was validated on measurements of a three-quarter waveplate and an equine tendon sample by a fiber-based swept-source CPM-PS-OCT system.

Using NASA's Reference Architecture: Comparing Polar and Geostationary Data Processing Systems

NASA Technical Reports Server (NTRS)

Ullman, Richard; Burnett, Michael

2013-01-01

The JPSS and GOES-R programs are housed at NASA GSFC and jointly implemented by NASA and NOAA to NOAA requirements. NASA's role in the JPSS Ground System is to develop and deploy the system according to NOAA requirements. NASA's role in the GOES-R ground segment is to provide Systems Engineering expertise and oversight for NOAA's development and deployment of the system. NASA's Earth Science Data Systems Reference Architecture is a document developed by NASA's Earth Science Data Systems Standards Process Group that describes a NASA Earth Observing Mission Ground system as a generic abstraction. The authors work within the respective ground segment projects and are also separately contributors to the Reference Architecture document. Opinions expressed are the author's only and are not NOAA, NASA or the Ground Projects' official positions.