Science.gov

Sample records for dual axis radiographic

  1. Status of the Dual-Axis Radiographic Hydrodynamics Test Facility

    SciTech Connect

    Burns, M.J.; Allison, P.W.; Carlson, R.L.; Downing, J.N.; Moir, D.C.; Shurter, R.P.

    1996-09-01

    The Dual-Axis Radiographic Hydrodynamics Test (DARHT) Facility will employ two electron linear induction accelerators to produce intense, bremsstrahlung x-ray pulses for flash radiography with sub-millimeter spatial resolution of very dense (attentuations>10{sup 5}), dynamic objects. We will produce an intense x-ray pulse using a 19.75-MeV, 3.5-4 kA, 60-ns flattop electron beam focused on a tungsten target. A 3.75-MeV injector with either a cold velvet cathode or a laser-driven photocathode will produce a beam to be accelerated through a series of 64 ferrite-loaded induction cells with solenoid focusing. Accelerator technology demonstrations have been underway for several years at the DARHT Integrated Test Stand and results including beam energy, emittance, and beam breakup measurements are discussed.

  2. Status of the Dual Axis Radiographic Hydrodynamics Test (DARHT) Facility

    NASA Astrophysics Data System (ADS)

    Burns, Michael J.; Caporaso, George J.; Carlsten, Bruce E.; Chen, Yu-Jiuan; Chow, Ken P.; Cook, Edward G.; Davis, Harold A.; Ekdahl, Carl A.; Fawley, William M.; Fortgang, Clifford M.; Hughes, Thomas P.; McCuistian, B. R. Trent; Nielsen, Kurt E.; Rutkowski, Henry L.; Sampayan, Steve; Waldron, Will L.; Watson, James A.; Westenskow, Glenn A.; Yu, Simon S.

    2002-12-01

    The Dual-Axis Radiographic Hydrodynamics Test (DARHT) facility will employ two perpendicular electron Linear Induction Accelerators to produce intense, bremsstrahlung x-ray pulses for flash radiography. We intend to produce measurements containing three-dimensional information with sub-millimeter spatial resolution of the interior features of very dense, explosively-driven objects. The facility will be completed in two phases with the first phase having become operational in July 1999 utilizing a single-pulse, 20-MeV, 2-kA, 60-ns accelerator, a high-resolution electro-optical x-ray imaging system, and other hydrodynamics testing systems. We will briefly describe this machine. The first electron beams will be generated in the second phase of DARHT this year. The second DARHT accelerator consists of a 18.4-MeV, 2-kA, 2-microsecond pulse-width accelerator. Four short electron micropulses of variable pulse-width and spacing will be chopped out of the original, long accelerator pulse for producing time-resolved x-ray images. The second phase also features an extended, high-resolution electro-optical x-ray system with a framing speed of about 2-MHz. We will discuss this accelerator by summarizing the overall design of the long-pulse injector and accelerator. We will also discuss the fast kicker used to separate the long-pulse beam into short bursts suitable for radiography.

  3. Transverse beam motion on the second axis of the dual axis radiographic hydrodynamic test facility

    SciTech Connect

    Caporaso, G J; Chen, Y J; Fawley, W M; Paul, A C

    1999-03-23

    The accelerator on the second-axis of the Dual-Axis Radiographic Hydrodynamic Test (DARHT-II) facility will generate a 20 MeV, 2-4 kA, 2 µs long electron beam with an energy variation {<=} ± 0.5%. Four short current pulses with various lengths will be selected out of this 2 µs long current pulse and delivered to an x-ray converter target. The DARHT-II radiographic resolution requires these electron pulses to be focused to sub-millimeter spots on Bremsstrahlung targets with peak-to-peak transverse beam motion less than a few hundred microns. We have modeled the transverse beam motion, including the beam breakup instability, corkscrew motion, transverse resistive wall instability and beam induced transverse deflection in the kicker system, from the DARHT-II injector exit to the x-ray converter target. Simulations show that the transverse motion at the x-ray converters satisfies the DARHT-II radiographic requirements.

  4. Dual Axis Radiographic Hydrodynamic Test Facility mitigation action plan. Annual report for 1998

    SciTech Connect

    Haagenstad, T.

    1999-01-15

    This Mitigation Action Plan Annual Report (MAPAR) has been prepared as part of implementing the Dual Axis Radiographic Hydrodynamic Test Facility (DARHT) Mitigation Action Plan (MAP) to protect workers, soils, water, and biotic and cultural resources in and around the facility.

  5. The dual axis radiographic hydrodynamic test (DARHT) facility personnel safety system (PSS) control system

    SciTech Connect

    Jacquez, Edward B

    2008-01-01

    The mission of the Dual Axis Radiograph Hydrodynamic Test (DARHT) Facility is to conduct experiments on dynamic events of extremely dense materials. The PSS control system is designed specifically to prevent personnel from becoming exposed to radiation and explosive hazards during machine operations and/or the firing site operation. This paper will outline the Radiation Safety System (RSS) and the High Explosive Safety System (HESS) which are computer-controlled sets of positive interlocks, warning devices, and other exclusion mechanisms that together form the PSS.

  6. Dual axis radiographic hydrodynamic test facility. Final environmental impact statement, Volume 2: Public comments and responses

    SciTech Connect

    1995-08-01

    On May 12, 1995, the U.S. Department of Energy (DOE) issued the draft Dual Axis Radiographic Hydrodynamic Test Facility Environmental Impact Statement (DARHT EIS) for review by the State of New Mexico, Indian Tribes, local governments, other Federal agencies, and the general public. DOE invited comments on the accuracy and adequacy of the draft EIS and any other matters pertaining to their environmental reviews. The formal comment period ran for 45 days, to June 26, 1995, although DOE indicated that late comments would be considered to the extent possible. As part of the public comment process, DOE held two public hearings in Los Alamos and Santa Fe, New Mexico, on May 31 and June 1, 1995. In addition, DOE made the draft classified supplement to the DARHT EIS available for review by appropriately cleared individuals with a need to know the classified information. Reviewers of the classified material included the State of New Mexico, the U.S. Environmental Protection Agency, the Department of Defense, and certain Indian Tribes. Volume 2 of the final DARHT EIS contains three chapters. Chapter 1 includes a collective summary of the comments received and DOE`s response. Chapter 2 contains the full text of the public comments on the draft DARHT EIS received by DOE. Chapter 3 contains DOE`s responses to the public comments and an indication as to how the comments were considered in the final EIS.

  7. DARHT operations and maintenance manual. [Dual Axis Radiographic Hydrodynamic Test (DARHT)

    SciTech Connect

    Not Available

    1991-12-01

    The Dual Axis Radiographic Hydrodynamic Test (DARHT) injector system was designed, constructed and tested in the dummy load configuration at Pulse Sciences, Inc. (PSI), San Leandro, CA for Los Alamos National Laboratories (LANL) during the period from September 1989 through December 1990. The injector was installed and its operation was demonstrated in the dummy load configuration at LANL from January 1991 through April 1991. Testing of the system configuration into a diode load began in June 1991. Cross-sectional views of the injector in both the dummy load and system configurations are shown. The injector is designed to produce a 4 MV, flat-top ([plus minus] 1%), 65 nsec (99--99%) acceleration pulse into a 150 ohm load with a command fire jitter of less than 3 nsec (3[sigma]). The load consists of an adjustable sodium thiosulfate solution resistor located at the vacuum tube interface in parallel with an [approximately]1 k[Omega] electron beam diode. This manual describes the injector and its ancillary systems and gives operating, maintenance and assembly instructions for the system in the dummy load configuration.

  8. Induction cell breakdown experiments for the Dual-Axis Radiographic Hydrotest (DARHT) Facility

    SciTech Connect

    Earley, L.M.; Barnes, G.A.; Eversole, S.A.; Kauppila, T.J.; Keel, G.; Liska, D.J.; Moir, D.C.; Parsons, W.M.; Rader, D.C.

    1991-01-01

    Linear induction cells for the Dual-Axis Radiographic Hydrotest (DARHT) Facility have been tested to determine their high-voltage breakdown characteristics. A variety of full scale insulators were tested both in actual cells and in fixtures simulating induction cells. All insulators were constructed using cross-linked polystyrene (Rexolite). High-voltage pulses up to 550 kV were applied to the insulators using both a 60-ns pulse Blumlein and a 200-ns pulse cable Marx. Two different vacuum gaps were used in these tests, 1.46 and 1.91 cm. The tests were performed at various vacuum levels ranging from 1 {times} 10{sup {minus}6} to 5 {times} 10{sup {minus}8} torr. Breakdown tests of the insulators were also performed with an electron beam generated in the vacuum gap through the use of a velvet emitter. The gap voltage and current were measured using calibrated E-dot and B-dot probes. 15 refs., 7 figs.

  9. Dual Axis Radiographic Hydrodynamic Test Facility mitigation action plan. Annual report for 1997

    SciTech Connect

    Haagenstad, H.T.

    1998-01-15

    This Mitigation Action Plan Annual Report (MAPAR) has been prepared by the US Department of Energy (DOE) as part of implementing the Dual Axis Radiographic Hydrodynamic Test Facility (DARHT) Mitigation Action Plan (MAP). This MAPAR provides a status on specific DARHT facility design- and construction-related mitigation actions that have been initiated in order to fulfill DOE`s commitments under the DARHT MAP. The functions of the DARHT MAP are to (1) document potentially adverse environmental impacts of the Phased Containment Option delineated in the Final EIS, (2) identify commitments made in the Final EIS and ROD to mitigate those potential impacts, and (3) establish Action Plans to carry out each commitment (DOE 1996). The DARHT MAP is divided into eight sections. Sections 1--5 provide background information regarding the NEPA review of the DARHT project and an introduction to the associated MAP. Section 6 references the Mitigation Action Summary Table which summaries the potential impacts and mitigation measures; indicates whether the mitigation is design-, construction-, or operational-related; the organization responsible for the mitigation measure; and the projected or actual completion data for each mitigation measure. Sections 7 and 8 discuss the Mitigation Action Plan Annual Report and Tracking System commitment and the Potential Impacts, Commitments, and Action Plans respectively. Under Section 8, potential impacts are categorized into five areas of concern: General Environment, including impacts to air and water; Soils, especially impacts affecting soil loss and contamination; Biotic Resources, especially impacts affecting threatened and endangered species; Cultural/Paleontological Resources, especially impacts affecting the archeological site known as Nake`muu; and Human Health and Safety, especially impacts pertaining to noise and radiation. Each potential impact includes a brief statement of the nature of the impact and its cause(s). The commitment

  10. Radionuclides in Small Mammals Collected at the Dual-Axis Radiographic Hydrodynamic Test (DARHT) Facility during 2001-- 2003

    SciTech Connect

    P.R. Fresquez

    2005-01-20

    Rodents are effective indicators of environmental contamination and the Dual-Axis Radiographic Hydrodynamic Test (DARHT) Facility Mitigation Action Plan specifies the (radionuclide) comparison of small mammals to baseline levels to determine if there are any impacts as a result of operations. Consequently, samples of (whole body) field mice (Peromyscus spp.) were collected from within the grounds of the DARHT facility at Los Alamos National Laboratory, Technical Area 15, from 2001 through 2003. Samples were analyzed for {sup 3}H, {sup 137}Cs, {sup 90}Sr, {sup 241}Am, {sup 238}Pu, {sup 239,240}Pu, {sup 234}U, {sup 235}U, and {sup 238}U. Results, which represent three years since the start of operations in 2000, were compared with baseline statistical reference level (BSRL) data established over a four-year-long preoperational period. Most radionuclides in mice were either at nondetectable levels or within BSRLs. The few radionuclides that were above BSRLs included U isotopes; and the ratios of some samples indicated depleted U sources. Although the amounts of U in some samples were just above BSRLs, and since depleted U is less soluble and less toxic (chemical and radioactive) than naturally occurring U, the very small levels in the mice collected around the DARHT facility grounds are unlikely to pose a threat to predators that feed upon them.

  11. Concentrations of Radionuclides and Trace Elements in Environmantal Media arond te Dual-Axis Radiographic Hydrodynamic Test Facilit at Los Alamos National Laboratory during 2005

    SciTech Connect

    G.J.Gonzales; P.R. Fresquez; C.D.Hathcock; D.C. Keller

    2006-05-15

    The Mitigation Action Plan (MAP) for the Dual-Axis Radiographic Hydrodynamic Test (DARHT) facility at Los Alamos National Laboratory requires that samples of biotic and abiotic media be collected after operations began to determine if there are any human health or environmental impacts. The DARHT facility is the Laboratory's principal explosive test facility. To this end, samples of soil and sediment, vegetation, bees, and birds were collected around the facility in 2005 and analyzed for concentrations of {sup 3}H, {sup 137}Cs, {sup 90}Sr, {sup 238}Pu, {sup 239,240}Pu, {sup 241}Am, {sup 234}U, {sup 235}U, {sup 238}U, Ag, As, Ba, Be, Cd, Cr, Cu, Hg, Ni, Pb, Sb, Se, and Tl. Bird populations have also been monitored. Contaminant results, which represent up to six sample years since the start of operations, were compared with (1) baseline statistical reference levels (BSRLs) established over a four-year preoperational period before DARHT facility operations, (2) screening levels (SLs), and (3) regulatory standards. Most radionuclides and trace elements were below BSRLs and those few samples that contained radionuclides and trace elements above BSRLs were below SLs. Concentrations of radionuclides and nonradionuclides in biotic and abiotic media around the DARHT facility do not pose a significant human health hazard. The total number of birds captured and number of species represented were similar in 2003 and 2004, but both of these parameters increased substantially in 2005. Periodic interruption of the scope and schedule identified in the MAP generally should have no impact on meeting the intent of the MAP. The risk of not sampling one of the five media in any given year is that if a significant impact to contaminant levels were to occur there would exist a less complete understanding of the extent of the change to the baseline for these media and to the ecosystem as a whole. Since the MAP is a requirement that was established under the regulatory framework of the

  12. Shot H3837: Darht's first dual-axis explosive experiment

    NASA Astrophysics Data System (ADS)

    Harsh, James F.; Hull, Lawrence; Mendez, Jacob; McNeil, Wendy Vogan

    2012-03-01

    Test H3837 was the first explosive shot performed in front of both flash x-ray axes at the Los Alamos Dual Axis Radiographic Hydrodynamic Test (DARHT) facility. Executed in November 2009, the shot was an explosively-driven metal flyer plate in a series of experiments designed to explore equation-of-state properties of shocked materials. Imaging the initial shock wave traveling through the flyer plate, DARHT Axis II captured the range of motion from the shock front emergence in the flyer to breakout at the free surface; the Axis I pulse provided a perpendicular perspective of the shot at a time coinciding with the third pulse of Axis II.

  13. Shot H3837: Darht's First Dual-Axis Explosive Experiment

    NASA Astrophysics Data System (ADS)

    Mendez, Jacob; McNeil, Wendy Vogan; Harsh, James; Hull, Lawrence

    2011-06-01

    Test H3837 was the first explosive shot performed in front of both flash x-ray axes at the Los Alamos Dual Axis Radiographic HydroTest (DARHT) facility. Executed in November 2009, the shot was an explosively-driven metal flyer plate in a series of experiments designed to explore equation-of-state properties of shocked materials. Imaging the initial shock wave traveling through the flyer plate, DARHT Axis II captured the range of motion from the shock front emergence in the flyer to breakout at the free surface; the Axis I pulse provided a perpendicular perspective of the shot at a time coinciding with the third pulse of Axis II. Since the days of the Manhattan Project, penetrating radiography with multiple frames from different viewing angles has remained a high-profile goal at the Laboratory. H3837 is merely the beginning of a bright future for two-axis penetrating radiography.

  14. Dual Axis Light Sensor for Tracking Sun

    NASA Astrophysics Data System (ADS)

    Shibata, Miki; Tambo, Toyokazu

    We have developed convenient light sensors to control a platform of solar cell panel. Dual axis light sensor in the present paper has structure of 5 PD (photodiode) light sensor which is composed of 5 photodiodes attached on a frustum of pyramid(1). Light source can be captured in front of the sensor by rotating the X and Y axis as decreasing the output deviation between two pairs of outside photodiodes. We here report the mechanism of sun tacking using the dual axis 5 PD light sensor and the fundamental results performed in the dark room.

  15. Micromachined dual input axis rate gyroscope

    NASA Astrophysics Data System (ADS)

    Juneau, Thor Nelson

    The need for inexpensive yet reliable angular rate sensors in fields ranging from automotive to consumer electronics has motivated prolific micromachined rate gyroscope research. The vast majority of research has focused on single input axis rate gyroscopes based upon either translational resonance, such as tuning forks, or structural mode resonance, such as vibrating rings. However, this work presents a novel, contrasting approach based on angular resonance of a rotating rigid rotor suspended by torsional springs. The inherent symmetry of the circular design allows angular rate measurement about two axes simultaneously, hence the name micromachined dual-axis rate gyroscope. The underlying theory of operation, mechanical structure design optimization, electrical interface circuitry, and signal processing are described in detail. Several operational versions were fabricated using two different fully integrated surface micromachining processes as proof of concept. The heart of the dual-axis rate gyroscope is a ˜2 mum thick polysilicon disk or rotor suspended above the substrate by a four beam suspension. When this rotor in driven into angular oscillation about the axis perpendicular to the substrate, a rotation rate about the two axes parallel to the substrate invokes an out of plane rotor tilting motion due to Coriolis acceleration. This tilting motion is capacitively measured and on board integrated signal processing provides two output voltages proportional to angular rate input about the two axes parallel to the substrate. The design process begins with the derivation of gyroscopic dynamics. The equations suggest that tuning sense mode frequencies to the drive oscillation frequency can vastly increase mechanical sensitivity. Hence the supporting four beam suspension is designed such that electrostatic tuning can match modes despite process variations. The electrostatic tuning range is limited only by rotor collapse to the substrate when tuning-voltage induced

  16. Static-stress analysis of dual-axis confinement vessel

    NASA Astrophysics Data System (ADS)

    Bultman, D. H.

    1992-11-01

    This study evaluates the static-pressure containment capability of a 6-ft-diameter, spherical vessel, made of HSLA-100 steel, to be used for high-explosive (HE) containment. The confinement vessel is designed for use with the Dual-Axis Radiographic Hydrotest Facility (DARHT) being developed at Los Alamos National Laboratory. Two sets of openings in the vessel are covered with x-ray transparent covers to allow radiographic imaging of an explosion as it occurs inside the vessel. The confinement vessel is analyzed as a pressure vessel based on the ASME Boiler and Pressure Vessel Code, Section 8, Division 1, and the Welding Research Council Bulletin, WRC-107. Combined stresses resulting from internal pressure and external loads on nozzles are calculated and compared with the allowable stresses for HSLA-100 steel. Results confirm that the shell and nozzles of the confinement vessel are adequately designed to safely contain the maximum residual pressure of 1675 psi that would result from an HE charge of 24.2 kg detonated in a vacuum. Shell stresses at the shell-to-nozzle interface, produced from external loads on the nozzles, were less than 400 psi. The maximum combined stress resulting from the internal pressure plus external loads was 16,070 psi, which is less than half the allowable stress of 42,375 psi for HSLA-100 steel.

  17. Force-balanced dual-axis microgyroscope

    NASA Astrophysics Data System (ADS)

    An, Seungdo; Oh, Yong-Soo; Lee, Byeungleul; Park, Kyu-Yeon; Go, Youn-il; Kim, Jeong-gon; Song, Ci M.; Lee, Seungseob

    1997-11-01

    The surface micromachining process realized the dual-axis microgyroscope. The 7.5 micrometers -thick polysilicon layer deposited by LPCVD is used for the vibrating structure. In this research, we present a new structure with high angular inertia momentum and compact size. In particular, this structure can utilize a simple force-balancing torsional torque which does not need another top electrode layer to reduce the intrinsic non-linearity of a capacitive-type sensor. The gyroscope is tested in a high vacuum chamber for a high Q-factor. The sensing mode is separated 2 percent from the driving mode by applying the inter-plate DC tuning bias. The experiment resulted in a nose equivalent signal of 0.1 deg/sec.

  18. Dual Axis Target Mapping and Automated Sequential Acquisition of Dual Axis EM Tomographic Data

    PubMed Central

    Zheng, Shawn Q.; Matsuda, Atsushi; Braunfeld, Michael B.; Sedat, John W.; Agard, David A.

    2009-01-01

    Dual-axis electron microscopic tomography minimizes the missing wedge-induced resolution loss by taking two complementary tilt data sets of the same target along two orthogonal axes. The potential of this powerful approach has been hampered by the practical challenges inherent in finding the original targets that are dramatically displaced due to non-eucentric specimen rotation. Not only is the manual search for the original targets time consuming and tedious but the added dose during manual searching is uncontrollable. We have developed a hierarchical alignment scheme that allows tomographic data to be collected from an arbitrary number of target sites in one grid orientation and then to find and collect orthogonal data sets with little or no user intervention. Inspired by the successful multi-scale mapping in Leginon, our alignment is performed in three levels to gradually pinpoint the original targets. At the lowest level the grid lattice is used to determine the rotation angle and translational shift resulting from specimen rotation via auto- and cross-correlative analysis of a pair of atlas maps constructed before and after specimen rotation. The target locations are further refined at the next level using a pair of smaller atlas maps. The final refinement of target positions is done by aligning the target contained image tiles. Given the batch processing nature of this hierarchical alignment, multiple targets are initially selected in a group and then sequentially acquired. Upon completion of the data collection on all the targets along the first axis and after specimen rotation, the hierarchical alignment is performed to relocate the original targets. The data collection is then resumed on these targets for the second axis. Therefore, only one specimen rotation is needed for collecting multiple dual-axis tomographic data sets. The experiment of acquiring 20S Proteasomes dual-axis tomographic data sets in vitreous ice at 86000x CCD magnification on our FEI

  19. Static-stress analysis of dual-axis safety vessel

    NASA Astrophysics Data System (ADS)

    Bultman, D. H.

    1992-11-01

    An 8 ft diameter safety vessel, made of HSLA-100 steel, is evaluated to determine its ability to contain the quasi-static residual pressure from a high explosive (HE) blast. The safety vessel is designed for use with the Dual-Axis Radiographic Hydrotest (DARHT) facility being developed at Los Alamos National Laboratory. A smaller confinement vessel fits inside the safety vessel and contains the actual explosion, and the safety vessel functions as a second layer of containment in the unlikely case of a confinement vessel leak. The safety vessel is analyzed as a pressure vessel based on the ASME Boiler and Pressure Vessel Code, Section 8, Division 1, and the Welding Research Council Bulletin, WRC107. Combined stresses that result from internal pressure and external loads on nozzles are calculated and compared to the allowable stresses for HSLA-100 steel. Results confirm that the shell and nozzle components are adequately designed for a static pressure of 830 psi, plus the maximum expected external loads. Shell stresses at the 'shell to nozzle' interface, produced from external loads on the nozzles, were less than 700 psi. The maximum combined stress resulting from the internal pressure plus external loads was 17,384 psi, which is significantly less than the allowable stress of 42,375 psi for HSLA-100 steel.

  20. Human performance evaluation in dual-axis critical task tracking

    NASA Technical Reports Server (NTRS)

    Ritchie, M. L.; Nataraj, N. S.

    1975-01-01

    A dual axis tracking using a multiloop critical task was set up to evaluate human performance. The effects of control stick variation and display formats are evaluated. A secondary loading was used to measure the degradation in tracking performance.

  1. Development of a dual-axis optoelectronic precision level

    NASA Astrophysics Data System (ADS)

    Fan, Kuang-Chao; Wang, Tsung-Han; Lin, Sheng-Yi; Liu, Yen-Chih

    2011-12-01

    This paper presents the design principle and applications of a innovative dual-axis optoelectronic level. A commercially available DVD pickup head is adopted as the angle sensor in association with the double-layer pendulum mechanism for dual-axis swings. A mass-damping system is analyzed to model the mechanical dynamics. Measured angles of both axes are processed by a microprocessor and displayed on a LCD or exported to an external PC. Compared with a triple-beam laser angular interferometer, the error of the dual-axis optoelectronic level is better than +/-0.5 arc-seconds in the measuring range of +/-20 arc-seconds, and the settling time is within 0.5 sec. Two experimental results show the consistency with a Renishaw interfereometer and its practical use in industry.

  2. Dual-axis hole-drilling ESPI residual stress measurements

    SciTech Connect

    Steinzig, Michael; Schajer, Gary

    2008-01-01

    A novel dual-axis ESPI hole-drilling residual stress measurement method is presented. The method enables the evaluation of all the in-plane normal stress components with similar response to measurement errors, significantly lower than with single-axis measurements. A numerical method is described that takes advantage of, and compactly handles, the additional optical data that are available from the second measurement axis. Experimental tests were conducted on a calibrated specimen to demonstrate the proposed method, and the results supported theoretical expectations.

  3. DARHT status and preparations for dual-axis hydrotesting (u)

    SciTech Connect

    Bowman, David W

    2010-01-01

    The status of the DARHT facility, including a history of events that have taken place since the end of the DARHT Second Axis Refurbishment Project, is discussed. Technical and operational enhancements that have been made will be addressed, and recent technical challenges, such as the RF noise in the kicker region, are discussed. Historical data on reliability of the second axis is discussed, as well as operational changes made to enhance reliability. In addition, the path forward for integrating the second axis into overall DARHT operations in preparation for a hydrotest is addressed. Timing integration tests are accompanied by a series of tests to evaluate neutron contamination and cross-axis scatter, with attempts being made to provide adequate shielding to minimize the effects of neutrons and cross-beam scatter. The discussion includes results of the testing performed to-date, and concludes with a discussion of the path forward for dual-axis hydrotesting at DARHT.

  4. Dual axis operation of a micromachined rate gyroscope

    SciTech Connect

    Juneau, T.; Pisano, A.P.; Smith, J.

    1997-04-01

    Since micromachining technology has raised the prospect of fabricating high performance sensors without the associated high cost and large size, many researchers have investigated micromachined rate gyroscopes. The vast majority of research has focused on single input axis rate gyroscopes, but this paper presents work on a dual input axis micromachined rate gyroscope. The key to successful simultaneous dual axis operation is the quad symmetry of the circular oscillating rotor design. Untuned gyroscopes with mismatched modes yielded random walk as low as 10{degrees}/{radical}hour with cross sensitivity ranging from 6% to 16%. Mode frequency matching via electrostatic tuning allowed performance better than 2{degrees}/{radical}hour, but at the expense of excessive cross sensitivity.

  5. Validation of neck axis distance as a radiographic measure for acetabular anteversion

    PubMed Central

    Nitschke, Ashley; Petersen, Brian; Lambert, Jeffery R.; Glueck, Deborah H.; Jesse, Mary Kristen; Strickland, Colin; Mei-Dan, Omer

    2016-01-01

    Excessive acetabular anteversion is an important treatment consideration in hip preservation surgery. There is currently no reliable quantitative method for determining acetabular anteversion utilizing radiographs alone. The three main purposes of this study were to: (i) define and validate the neck axis distance (NAD) as a new visual and reproducible semi-quantitative radiographic parameter used to measure acetabular anteversion; (ii) determine the degree of correlation between NAD and computed tomography (CT)-measured acetabular anteversion; (iii) establish a sensitive and specific threshold value for NAD to identify excessive acetabular anteversion. This retrospective cohort study included all patients presenting to a single institution over a 14-month period who had undergone a dedicated musculoskeletal CT pelvis along with a standardized anteroposterior (AP) pelvis radiograph. Trained observers measured the NAD on the AP pelvis radiograph and equatorial acetabular anteversion on CT for all hips. Mixed model analysis was used to find prediction equations, and ROC analysis was used to evaluate the diagnostic accuracy of NAD. NAD is a valid semi-quantitative predictor of acetabular anteversion and strongly correlates with CT-measured equatorial acetabular anteversion (P  <  0.0001). A NAD measurement of greater than 14 mm predicts excessive acetabular anteversion with 76% sensitivity and 78% specificity. NAD is an accurate radiographic predictor of acetabular anteversion, which may be readily used as an effective screening tool during the evaluation of patients with hip pain. PMID:27026824

  6. Dual-axis MEMS force sensors for gecko adhesion studies

    NASA Astrophysics Data System (ADS)

    Hill, Ginel Corina

    Dual-axis piezoresistive microelectromechanical systems (MEMS) force sensors were used to investigate the effects of orientation angle on the adhesion of gecko hairs, called setae. These hairs are part of a fantastic, robust dry adhesive. Their adhesion is highly angle-dependent, with both the "pitch" and "roll" orientation angles playing a role. This anisotropy in adhesion properties is critical for locomotion, as it enables detachment of the gecko's foot with limited pull-off force. Many synthetic mimics of the gecko adhesive are isotropic. This work on the anisotropy of natural setae will inform future work on synthetic dry adhesives. A dual-axis microscale force sensor was needed to study single seta adhesive forces, which are stronger parallel to a substrate than perpendicular. Piezoresistive silicon cantilevers that separately detect lateral and normal forces applied at the tip were used. The fabrication process and rigorous characterization of new devices are reported. A novel calibration method was developed that uses resonant frequency measurements in concert with finite element models to correct for the expected variability of critical dimensions. These corrected models were used to predict the stiffnesses of each cantilever, and thus improve the accuracy of force measurements made with these sensors. This calibration technique was also validated by direct measurement of the dual-axis cantilever stiffnesses using a reference cantilever. The adhesion force of a single gecko seta is dramatically enhanced by proper orientation. The dual-axis cantilevers were used to measure two components of force between a substrate and a Gekko gecko seta. Lateral adhesion was highest with the stalk oriented parallel to the surface at 0° pitch. Adhesion decreased smoothly as the pitch angle of the stalk was increased, until detachment or no adhesion occurred at approximately 30°. To display enhanced adhesion, the splayed tuft at the end of the seta needed to be only

  7. A procedure for denoising dual-axis swallowing accelerometry signals.

    PubMed

    Sejdić, Ervin; Steele, Catriona M; Chau, Tom

    2010-01-01

    Dual-axis swallowing accelerometry is an emerging tool for the assessment of dysphagia (swallowing difficulties). These signals however can be very noisy as a result of physiological and motion artifacts. In this note, we propose a novel scheme for denoising those signals, i.e. a computationally efficient search for the optimal denoising threshold within a reduced wavelet subspace. To determine a viable subspace, the algorithm relies on the minimum value of the estimated upper bound for the reconstruction error. A numerical analysis of the proposed scheme using synthetic test signals demonstrated that the proposed scheme is computationally more efficient than minimum noiseless description length (MNDL)-based denoising. It also yields smaller reconstruction errors than MNDL, SURE and Donoho denoising methods. When applied to dual-axis swallowing accelerometry signals, the proposed scheme exhibits improved performance for dry, wet and wet chin tuck swallows. These results are important for the further development of medical devices based on dual-axis swallowing accelerometry signals. PMID:19940343

  8. Scaling analysis of baseline dual-axis cervical accelerometry signals.

    PubMed

    Sejdić, Ervin; Steele, Catriona M; Chau, Tom

    2011-09-01

    Dual-axis cervical accelerometry is an emerging approach for the assessment of swallowing difficulties. However, the baseline signals, i.e., vibration signals with only quiet breathing or apnea but without swallowing, are not well understood. In particular, to comprehend the contaminant effects of head motion on cervical accelerometry, we need to study the scaling behavior of these baseline signals. Dual-axis accelerometry data were collected from 50 healthy adult participants under conditions of quiet breathing, apnea and selected head motions, all in the absence of swallowing. The denoised cervical vibrations were subjected to detrended fluctuation analysis with empirically determined first-order detrending. Strong persistence was identified in cervical vibration signals in both anterior-posterior (A-P) and superior-inferior (S-I) directions, under all the above experimental conditions. Vibrations in the A-P axes exhibited stronger correlations than those in the S-I axes, possibly as a result of axis-specific effects of vasomotion. In both axes, stronger correlations were found in the presence of head motion than without, suggesting that head movement significantly impacts baseline cervical accelerometry. No gender or age effects were found on statistical persistence of either vibration axes. Future developments of cervical accelerometry-based medical devices should actively mitigate the effects of head movement. PMID:20708292

  9. A dual-axis approach to understanding neuroendocrine development

    PubMed Central

    Shirtcliff, Elizabeth A; Dismukes, Andrew R.; Marceau, Kristine P.; Ruttle, Paula; Simmons, Julian; Han, Georges

    2015-01-01

    This paper on ‘a dual-axis approach to understanding neuroendocrine development’ sets out to introduce a series of paper about a novel perspective regarding stress and sex hormones, or what the authors within this special issue term ‘coupling’ of hypothalamic-pituitary-adrenal and –gonadal axes. This view postulates that these axes do not necessarily operate in opposition, but can operate together as evidenced empirically as a positive within-person association between stress hormones like cortisol or sex hormones like testosterone. A wealth of papers within the special issue demonstrate positive coupling across acute, diurnal, basal, and longitudinal timeframes and across several different types of contexts. Reviews were meant to challenge whether this was physiologically plausible. Consistently, sophisticated statistical models were utilized in order to show a template for how to model positive coupling and to ensure that coupling was a within-person phenomenon. We cautiously considered positive coupling until the consistency of observing positive coupling was robust enough for us to consider challenging the prevailing oppositional view of these axes. We do so to acknowledge that there are contexts, moments and stages in which the function of these axes should work together: for example when contexts are both stressful and challenging or at developmental stages (like adolescence) in which the youth must grow up despite the storm and stress of youth. We hope that by putting forward a functional dual-axis approach, the field will be able to consider when and how a dual-axis approach is useful. PMID:26220016

  10. AXIS: an instrument for imaging Compton radiographs using the Advanced Radiography Capability on the NIF.

    PubMed

    Hall, G N; Izumi, N; Tommasini, R; Carpenter, A C; Palmer, N E; Zacharias, R; Felker, B; Holder, J P; Allen, F V; Bell, P M; Bradley, D; Montesanti, R; Landen, O L

    2014-11-01

    Compton radiography is an important diagnostic for Inertial Confinement Fusion (ICF), as it provides a means to measure the density and asymmetries of the DT fuel in an ICF capsule near the time of peak compression. The AXIS instrument (ARC (Advanced Radiography Capability) X-ray Imaging System) is a gated detector in development for the National Ignition Facility (NIF), and will initially be capable of recording two Compton radiographs during a single NIF shot. The principal reason for the development of AXIS is the requirement for significantly improved detection quantum efficiency (DQE) at high x-ray energies. AXIS will be the detector for Compton radiography driven by the ARC laser, which will be used to produce Bremsstrahlung X-ray backlighter sources over the range of 50 keV-200 keV for this purpose. It is expected that AXIS will be capable of recording these high-energy x-rays with a DQE several times greater than other X-ray cameras at NIF, as well as providing a much larger field of view of the imploded capsule. AXIS will therefore provide an image with larger signal-to-noise that will allow the density and distribution of the compressed DT fuel to be measured with significantly greater accuracy as ICF experiments are tuned for ignition. PMID:25430200

  11. AXIS: An instrument for imaging Compton radiographs using the Advanced Radiography Capability on the NIF

    SciTech Connect

    Hall, G. N. Izumi, N.; Tommasini, R.; Carpenter, A. C.; Palmer, N. E.; Zacharias, R.; Felker, B.; Holder, J. P.; Allen, F. V.; Bell, P. M.; Bradley, D.; Montesanti, R.; Landen, O. L.

    2014-11-15

    Compton radiography is an important diagnostic for Inertial Confinement Fusion (ICF), as it provides a means to measure the density and asymmetries of the DT fuel in an ICF capsule near the time of peak compression. The AXIS instrument (ARC (Advanced Radiography Capability) X-ray Imaging System) is a gated detector in development for the National Ignition Facility (NIF), and will initially be capable of recording two Compton radiographs during a single NIF shot. The principal reason for the development of AXIS is the requirement for significantly improved detection quantum efficiency (DQE) at high x-ray energies. AXIS will be the detector for Compton radiography driven by the ARC laser, which will be used to produce Bremsstrahlung X-ray backlighter sources over the range of 50 keV–200 keV for this purpose. It is expected that AXIS will be capable of recording these high-energy x-rays with a DQE several times greater than other X-ray cameras at NIF, as well as providing a much larger field of view of the imploded capsule. AXIS will therefore provide an image with larger signal-to-noise that will allow the density and distribution of the compressed DT fuel to be measured with significantly greater accuracy as ICF experiments are tuned for ignition.

  12. Thermal performance of microinverters on dual-axis trackers

    NASA Astrophysics Data System (ADS)

    Hossain, Mohammad A.; Peshek, Timothy J.; Xu, Yifan; Ji, Liang; Sun, Jiayang; Abramson, Alexis; French, Roger H.

    2014-10-01

    Time-series insolation, environmental, thermal and power data were analyzed in a statistical analytical approach to identify the thermal performance of microinverters on dual-axis trackers under real-world operating conditions. This study analyzed 24 microinverters connected to 8 different brands of photovoltaic (PV) modules from July through October 2013 at the Solar Durability and Lifetime Extension (SDLE) SunFarm at Case Western Reserve University. Exploratory data analysis shows that the microinverter's temperature is strongly correlated with ambient temperature and PV module temperature, and moderately correlated with irradiance and AC power. Noontime data analysis reveals the variations of thermal behavior across different brands of PV module. Hierarchical clustering using the Euclidean distance measure principle was applied to noontime microinverter temperature data to group the similarly behaved microinverters. A multiple regression predictive model has been developed based on ambient temperature, PV module temperature, irradiance and AC power data to predict the microinverters temperature connected with different brands PV modules on dual-axis trackers.

  13. Radiographer.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Center on Education and Training for Employment.

    This document, which is designed for use in developing a tech prep competency profile for the occupation of radiographer, lists technical competencies and competency builders for 18 units pertinent to the health technologies cluster in general as well as those specific to the occupation of radiographer. The following skill areas are covered in the…

  14. Canine hip dysplasia radiographic screening. Prevalence of rotation of the pelvis along its length axis in 7,012 conventional hip extended radiographs.

    PubMed

    Genevois, J-P; Cachon, T; Fau, D; Carozzo, C; Viguier, E; Collard, F; Remy, D

    2007-01-01

    The prevalence of rotation of the pelvis along its length axis was noted, as was the number of rotations towards the right or left hand side of the dog, on 7,012 conventional hip extended radiographs, which were sent for official screening. 29.8% of the radiographs showed a rotation the pelvis. The rotation was statistically more frequent towards the left hand side of the dog. The number of rejected radiographs for too important pelvis rotation was only 5.2%. The consequences of the pelvis rotation on the Norberg-Olsson angle, on the dorsal femoral head coverage, and in the aspect of cranial acetabular edge have to be taken into account when scoring the dog for hip dysplasia. PMID:18038007

  15. Downstream Transport System for the Second Axis of the Dual-Axis Radiographic Hydrodynamic Test Facility

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Jiuan; Bertolini, Lou; Caporaso, George J.; Ho, Darwin D.-M.; McCarrick, James F.; Paul, Arthur C.; Pincosy, Philip A.; Poole, Brian R.; Wang, Li-Fang; Westenskow, Glen A.

    2002-12-01

    This paper presents physics design of the DARHT-II downstream system, which consists of a diagnostic beam stop, a novel, fast, high-precision kicker system and the x-ray converter target assembly. The beamline configuration and its beam parameter acceptance, the transverse resistive wall instability modeling, the ion hose instability in the presence of the background gas, and the simulations of beam spill are discussed. We also present the target converter assembly's configuration, and the simulated x-ray spot sizes and doses based on the radiation hydrodynamics code LASNEX and the Monte Carlo radiation transport code MCNP.

  16. Final Focusing System for the Second Axis of the Dual-Axis Radiographic Hydrodynamic Test Facility

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Jiuan; McCarrick, James F.; Paul, Arthur C.; Westenskow, Glen A.

    2002-12-01

    The DARHT-II final focusing system consists of a solenoid and a foil, which is used to confine backstreaming ions. The separation between the converter target and the foil needs to be small to minimize the ion focusing effects. The beam spot size on the foil has to be large enough to ensure survivability of the foil while it is being struck by four high current pulses over 2 microsecond period. We have investigated several final focusing lens and focusing schemes. The simulation results of the beam spot size on the target are presented.

  17. A dual-axis approach to understanding neuroendocrine development.

    PubMed

    Shirtcliff, Elizabeth A; Dismukes, Andrew R; Marceau, Kristine; Ruttle, Paula L; Simmons, Julian G; Han, Georges

    2015-09-01

    This introduction sets out to present a series of paper about a novel perspective regarding stress and sex hormones, or what the authors within this special issue term "coupling" of hypothalamic-pituitary-adrenal and--gonadal axes. This view postulates that these axes do not necessarily operate in opposition, but can operate together as evidenced empirically as a positive within-person association between stress hormones like cortisol or sex hormones like testosterone. A wealth of papers within the special issue demonstrate positive coupling across acute, diurnal, basal, and longitudinal timeframes and across several different types of contexts. Reviews were meant to challenge whether this was physiologically plausible. Consistently, sophisticated statistical models were utilized in order to show a template for how to model positive coupling and to ensure that coupling was a within-person phenomenon. We cautiously considered positive coupling until the consistency of observing coupling was robust enough for us to consider challenging the prevailing oppositional view of these axes. We do so to acknowledge that there are contexts, moments and stages in which the function of these axes should work together: for example when contexts are both stressful and challenging or at developmental stages (like adolescence) in which the youth must grow up despite the storm and stress of youth. We hope that by putting forward a functional dual-axis approach, the field will be able to consider when and how these axes work together. PMID:26220016

  18. Measuring x-ray spectra of flash radiographic sources

    SciTech Connect

    Gehring, Amanda Elizabeth; Espy, Michelle A.; Haines, Todd Joseph; Mendez, Jacob; Moir, David C.; Sedillo, Robert; Shurter, Roger P.; Volegov, Petr Lvovich; Webb, Timothy J

    2015-11-02

    The x-ray spectra of flash radiographic sources is difficult to measure. The sources measured were Radiographic Integrated Test Stand-6 (370 rad at 1 m; 50 ns pulse) and Dual Axis Radiographic Hydrodynamic Test Facility (DARHT) (550 rad at 1 m; 50 ns pulse). Features of the Compton spectrometer are described, and spectra are shown. Additional slides present data on instrumental calibration.

  19. Dual axis translation apparatus and system for translating an optical beam and related method

    DOEpatents

    Cassidy, Kelly

    1991-01-01

    A dual axis translation device and system in accordance with this invention, for translating an optical beam along both an x-axis and a y-axis which are perpendicular to one another, has a beam directing means acting on said optical beam for directing the beam along a particular path transverse to said x and y axes. An arrangement supporting said beam directing means for movement in the x and y direction within a given plane is provided. The arrangement includes a first means for translating said beam directing means along the x-axis in said given plane in order to translate the beam along said x-axis. The arrangement comprises a second means for translating said beam directing means along the y-axis in said given plane in order to translate the beam along said y-axis.

  20. Modeling of magnetic Barkhausen noise in single and dual easy axis systems in steel

    NASA Astrophysics Data System (ADS)

    Krause, Thomas W.; Mandal, Kalyan; Atherton, David L.

    1999-04-01

    Angular dependent magnetic Barkhausen noise (MBN) signals measured on plate steel, and on the inside and outside surfaces of sections of seam welded and spiral welded 2% Mn steel pipe are modeled by considering a system of dipole moments. The relative orientation of dipole moments is fixed within the material, but their magnitude grows in the presence of an applied field. Growth of the moments is proportional to the magnetic field projected along a particular moment axis. A single easy axis material consists of an isotropically aligned population of moments, giving the background, upon which is superimposed a population of moments with relative orientations that result in a net moment within the sample. A dual easy axis system is proposed to consist of: (i) a second population of moments with orientations resulting in a net moment with orientation different from that of the first and (ii) interactions, possibly quadrupolar in nature, that occur between the individual moments of each population. The model is used to explain differences in the angular-dependent MBN signal between the seam welded pipe, with a single easy axis, and the spiral welded pipe, with a dual easy axis. The source of the dual easy axis system in the spiral welded pipe, which is different on the two pipe surfaces, is considered in terms of the asymmetric manufacturing processes, relative to the pipe axis, applied during its production.

  1. Analytical Modeling of Squeeze Film Damping in Dual Axis Torsion Microactuators

    NASA Astrophysics Data System (ADS)

    Moeenfard, Hamid

    2015-10-01

    In this paper, problem of squeeze film damping in dual axis torsion microactuators is modeled and closed form expressions are provided for damping torques around tilting axes of the actuator. The Reynolds equation which governs the pressure distribution underneath the actuator is linearized. The resulting equation is then solved analytically. The obtained pressure distribution is used to calculate the normalized damping torques around tilting axes of the actuator. Dependence of the damping torques on the design parameters of the dual axis torsion actuator is studied. It is observed that with proper selection of the actuator's aspect ratio, damping torque along one of the tilting directions can be eliminated. It is shown that when the tilting angles of the actuator are small, squeeze film damping would act like a linear viscous damping. The results of this paper can be used for accurate dynamical modeling and control of torsion dual axis microactuators.

  2. Optimal Spacing of Dual-axis Trackers for Concentrating Photovoltaic Systems

    NASA Astrophysics Data System (ADS)

    Kim, Yong Sin; Winston, Roland

    2011-12-01

    The levelized cost of energy (LCOE) is widely used to compare the cost of energy generation across technologies. In a utility-scale concentrating photovoltaic (CPV) system, the spacing of dual-axis trackers must be balanced with total energy harvested from modules to minimize LCOE. In this paper, a spacing method of dual-axis trackers in a CPV system is presented. Based on the definition of LCOE, a cost function is defined and optimized in terms of spacing related parameters. Various methods to estimate hourly direct normal irradiance (DNI) are investigated and m-by-n tracker array configurations to minimize the cost function are discussed.

  3. A laboratory simulation of a single-axis dual-level precision pointing system

    NASA Technical Reports Server (NTRS)

    Bullock, G. F.; Morrell, F. R.; Romanczyk, K. C.

    1973-01-01

    The laboratory simulation of a scaled single-axis dual-level control system for a large space telescope is demonstrated. The dual-level control system consists of a coarse-body-pointing system and a fine-pointing system, which uses an image motion compensator, an image dissector tube, and digital electronics. The results of the simulation indicate that the dual-level system can be used to provide tracking capability within one-tenth of a diffraction-limited image diameter of a 3-meter f/100 telescope for stars up to a +12.3 visual magnitude.

  4. A comparison of radiographic anatomic axis knee alignment measurements and cross-sectional associations with knee osteoarthritis

    PubMed Central

    Goulston, L.M.; Sanchez-Santos, M.T.; D'Angelo, S.; Leyland, K.M.; Hart, D.J.; Spector, T.D.; Cooper, C.; Dennison, E.M.; Hunter, D.; Arden, N.K.

    2016-01-01

    Summary Objective Malalignment is associated with knee osteoarthritis (KOA), however, the optimal anatomic axis (AA) knee alignment measurement on a standard limb radiograph (SLR) is unknown. This study compares one-point (1P) and two-point (2P) AA methods using three knee joint centre locations and examines cross-sectional associations with symptomatic radiographic knee osteoarthritis (SRKOA), radiographic knee osteoarthritis (RKOA) and knee pain. Methods AA alignment was measured six different ways using the KneeMorf software on 1058 SLRs from 584 women in the Chingford Study. Cross-sectional associations with principal outcome SRKOA combined with greatest reproducibility determined the optimal 1P and 2P AA method. Appropriate varus/neutral/valgus alignment categories were established using logistic regression with generalised estimating equation models fitted with restricted cubic spline function. Results The tibial plateau centre displayed greatest reproducibility and associations with SRKOA. As mean 1P and 2P values differed by >2°, new alignment categories were generated for 1P: varus <178°, neutral 178–182°, valgus >182° and for 2P methods: varus <180°, neutral 180–185°, valgus >185°. Varus vs neutral alignment was associated with a near 2-fold increase in SRKOA and RKOA, and valgus vs neutral for RKOA using 2P method. Nonsignificant associations were seen for 1P method for SRKOA, RKOA and knee pain. Conclusions AA alignment was associated with SRKOA and the tibial plateau centre had the strongest association. Differences in AA alignment when 1P vs 2P methods were compared indicated bespoke alignment categories were necessary. Further replication and validation with mechanical axis alignment comparison is required. PMID:26700504

  5. Dual-axis resonance testing of wind turbine blades

    DOEpatents

    Hughes, Scott; Musial, Walter; White, Darris

    2014-01-07

    An apparatus (100) for fatigue testing test articles (104) including wind turbine blades. The apparatus (100) includes a test stand (110) that rigidly supports an end (106) of the test article (104). An actuator assembly (120) is attached to the test article (104) and is adapted for substantially concurrently imparting first and second forcing functions in first and second directions on the test article (104), with the first and second directions being perpendicular to a longitudinal axis. A controller (130) transmits first and second sets of displacement signals (160, 164) to the actuator assembly (120) at two resonant frequencies of the test system (104). The displacement signals (160, 164) initiate the actuator assembly (120) to impart the forcing loads to concurrently oscillate the test article (104) in the first and second directions. With turbine blades, the blades (104) are resonant tested concurrently for fatigue in the flapwise and edgewise directions.

  6. Feasibility Study of Dual Energy Radiographic Imaging for Target Localization in Radiotherapy for Lung Tumors

    PubMed Central

    Huo, Jie; Zhu, Xianfeng; Dong, Yang; Yuan, Zhiyong; Wang, Ping; Wang, Xuemin; Wang, Gang; Hu, Xin-Hua; Feng, Yuanming

    2014-01-01

    Purpose Dual-energy (DE) radiographic imaging improves tissue discrimination by separating soft from hard tissues in the acquired images. This study was to establish a mathematic model of DE imaging based on intrinsic properties of tissues and quantitatively evaluate the feasibility of applying the DE imaging technique to tumor localization in radiotherapy. Methods We investigated the dependence of DE image quality on the radiological equivalent path length (EPL) of tissues with two phantoms using a stereoscopic x-ray imaging unit. 10 lung cancer patients who underwent radiotherapy each with gold markers implanted in the tumor were enrolled in the study approved by the hospital's Ethics Committee. The displacements of the centroids of the delineated gross tumor volumes (GTVs) in the digitally reconstructed radiograph (DRR) and in the bone-canceled DE image were compared with the averaged displacements of the centroids of gold markers to evaluate the feasibility of using DE imaging for tumor localization. Results The results of the phantom study indicated that the contrast-to-noise ratio (CNR) was linearly dependent on the difference of EPL and a mathematical model was established. The objects and backgrounds corresponding to ΔEPL less than 0.08 are visually indistinguishable in the bone-canceled DE image. The analysis of patient data showed that the tumor contrast in the bone-canceled images was improved significantly as compared with that in the original radiographic images and the accuracy of tumor localization using the DE imaging technique was comparable with that of using fiducial makers. Conclusion It is feasible to apply the technique for tumor localization in radiotherapy. PMID:25268643

  7. Lightweight dual-axis tracker designs for dish-based HCPV

    NASA Astrophysics Data System (ADS)

    Angel, Roger; Cuerden, Brian; Whiteside, Andy

    2014-09-01

    Dish-based HCPV holds the promise of solar electricity at lower cost than for flat panel PV, provided that the dual-axis tracker cost can be minimized. Here we outline first and second generation lightweight tracker designs that include supports for a rectangular array of square dish mirrors and receivers located at their foci.

  8. Sensorless and Power-Optimized Sun Tracking for CPV Applications Using Dual-Axis Trackers

    NASA Astrophysics Data System (ADS)

    Stalter, Olivier; Burger, Bruno

    2010-10-01

    Tracking mismatches can cause severe power drops and energy losses in a CPV system. Also, classical open-loop and closed-loop position controllers do not take the generator's output power into account. Therefore, a new sensorless and power-optimized dual-axis CPV tracking controller has been developed and is presented here.

  9. Handheld multispectral dual-axis confocal microscope for cervical cancer screening

    NASA Astrophysics Data System (ADS)

    Sarapukdee, Pongsak; Rattanavarin, Santi; Jarujareet, Ungkarn; Khemthongcharoen, Numfon; Jolivot, Romuald; Jung, Il Woong; López, Daniel; Mandella, Michael J.; Piyawattanametha, Wibool

    2013-03-01

    Our work demonstrates a MEMS based handheld dual-axis confocal microscope for cervical cancer screening. Imaging demonstration is performed with plant and animal tissue biopsies. The data is collected and displayed in real time with 2-5 Hz frame rates.

  10. Comparison of the apparent masses and cross-axis apparent masses of seated humans exposed to single- and dual-axis whole-body vibration

    NASA Astrophysics Data System (ADS)

    Mansfield, Neil J.; Maeda, Setsuo

    2006-12-01

    Humans are exposed to whole-body vibration in many types of environment. In almost all cases, the vibration to which the human is exposed comprises multi-axis vibration, such that vibration occurs in all directions simultaneously. Despite the complex nature of vibration to which humans are exposed in the workplace, almost all laboratory studies investigating the biomechanical response of the person have been completed using single-axis simulators. This paper presents a study whereby 15 male subjects were exposed to single-axis whole-body vibration in the x-, y- and z-directions and dual-axis vibration in the xy-, xz-, and yz-directions using a 6 degree-of-freedom vibration simulator. All vibration magnitudes were 0.4 ms -2 rms in each axis. Acceleration and force was measured in the x-, y-, and z-direction during all trials. Subjects sat in two postures ('back-on' and 'back-off') on a flat rigid seat. Apparent masses measured using single-axis and dual-axis vibration stimuli showed comparable results; similarly, cross-axis apparent masses (i.e. the ratio of the force in one direction to the acceleration in another direction) were almost identical for the single- and dual-axis vibration stimuli. All results were in agreement with data previously published using single-axis vibration. In most cases, the peaks in the apparent mass and the cross-axis apparent mass occurred at a slightly lower frequency for the dual-axis vibration than for the single-axis vibration. It is hypothesised that this change is due to a nonlinear effect, analogous to that which occurs with increasing vibration magnitude for single-axis vibration.

  11. Off-axis point spread function reconstruction from a dual deformable mirror adaptive optics system

    NASA Astrophysics Data System (ADS)

    Keskin, O.; Conan, R.; Bradley, C.; Blain, C.

    2008-07-01

    In AO applications, PSF reconstruction is used in calibrating image analysis techniques for astrometry, and in the deconvolution of images to enhance their contrast. The partial correction provided by the AO system is due to the finite sampling of the wavefront sensor, the DM (limited number of freedoms on the DM, i.e., the number of actuators) and the finite bandwidth of the control system. Furthermore, the correction provided by an AO system degrades across the field of view, depending on the angular separation between the guide star and the target object (anisoplanatism). In this paper, an end to end numerical model of an off-axis dual DM AO system has been implemented to accommodate for the anisoplanatic errors that degrade the performance of AO systems at greater angular distances from the guide star. An improved off-axis PSF reconstruction methodology has been developed and numerically evaluated for the dual DM (Woofer/Tweeter) off-axis AO architecture.

  12. Design of a dual-axis optoelectronic level for precision angle measurements

    NASA Astrophysics Data System (ADS)

    Fan, Kuang-Chao; Wang, Tsung-Han; Lin, Sheng-Yi; Liu, Yen-Chih

    2011-05-01

    The accuracy of machine tools is mainly determined by angular errors during linear motion according to the well-known Abbe principle. Precision angle measurement is important to precision machines. This paper presents the theory and experiments of a new dual-axis optoelectronic level with low cost and high precision. The system adopts a commercial DVD pickup head as the angle sensor in association with the double-layer pendulum mechanism for two-axis swings, respectively. In data processing with a microprocessor, the measured angles of both axes can be displayed on an LCD or exported to an external PC. Calibrated by a triple-beam laser angular interferometer, the error of the dual-axis optoelectronic level is better than ±0.7 arcsec in the measuring range of ±30 arcsec, and the settling time is within 0.5 s. Experiments show the applicability to the inspection of precision machines.

  13. Evaluation of the prototype dual-axis wall attitude measurement sensor

    NASA Technical Reports Server (NTRS)

    Wong, Douglas T.

    1994-01-01

    A prototype dual-axis electrolytic tilt sensor package for angular position measurements was built and evaluated in a laboratory environment. The objective was to investigate the use of this package for making wind tunnel wall attitude measurements for the National Transonic Facility (NTF) at NASA Langley Research Center (LaRC). The instrumentation may replace an existing, more costly, and less rugged servo accelerometer package (angle-of-attack package) currently in use. The dual-axis electrolytic tilt sensor package contains two commercial electrolytic tilt sensors thermally insulated with NTF foam, all housed within a stainless steel package. The package is actively heated and maintained at 160 F using foil heating elements. The laboratory evaluation consisted of a series of tests to characterize the linearity, repeatability, cross-axis interaction, lead wire effect, step response, thermal time constant, and rectification errors. Tests revealed that the total RMS errors for the x-axis sensor is 0.084 degree, and 0.182 degree for the y-axis sensor. The RMS errors are greater than the 0.01 degree specification required for NTF wall attitude measurements. It is therefore not a viable replacement for the angle-of-attack package in the NTF application. However, with some physical modifications, it can be used as an inexpensive 5-degree range dual-axis inclinometer with overall accuracy approaching 0.01 degree under less harsh environments. Also, the data obtained from the tests can be valuable for wind tunnel applications of most types of electrolytic tilt sensors.

  14. Sheet-scanned dual-axis confocal (SS-DAC) microscopy using Richardson-Lucy deconvolution

    PubMed Central

    Wang, Danni; Meza, Daphne; Wang, Yu; Gao, Liang; Liu, Jonathan T.C.

    2015-01-01

    We have previously developed a line-scanned dual-axis confocal (LS-DAC) microscope with subcellular resolution suitable for high-frame-rate diagnostic imaging at shallow depths. Due to the loss of confocality along one dimension, the contrast (signal-to-background ratio) of a LS-DAC microscope is deteriorated compared to a point-scanned DAC microscope. However, by using a sCMOS camera for detection, a short oblique light-sheet is imaged at each scanned position. Therefore, by scanning the light sheet in only one dimension, a thin 3D volume is imaged. Both sequential two-dimensional deconvolution and three-dimensional deconvolution are performed on the thin image volume to improve the resolution and contrast of one en face confocal image section at the center of the volume, a technique we call sheet-scanned dual-axis confocal (SS-DAC) microscopy. PMID:26466290

  15. Sheet-scanned dual-axis confocal microscopy using Richardson-Lucy deconvolution.

    PubMed

    Wang, D; Meza, D; Wang, Y; Gao, L; Liu, J T C

    2014-09-15

    We have previously developed a line-scanned dual-axis confocal (LS-DAC) microscope with subcellular resolution suitable for high-frame-rate diagnostic imaging at shallow depths. Due to the loss of confocality along one dimension, the contrast (signal-to-background ratio) of a LS-DAC microscope is deteriorated compared to a point-scanned DAC microscope. However, by using a sCMOS camera for detection, a short oblique light-sheet is imaged at each scanned position. Therefore, by scanning the light sheet in only one dimension, a thin 3D volume is imaged. Both sequential two-dimensional deconvolution and three-dimensional deconvolution are performed on the thin image volume to improve the resolution and contrast of one en face confocal image section at the center of the volume, a technique we call sheet-scanned dual-axis confocal (SS-DAC) microscopy. PMID:26466290

  16. Tracking formulas and strategies for a receiver oriented dual-axis tracking toroidal heliostat

    SciTech Connect

    Guo, Minghuan; Wang, Zhifeng; Liang, Wenfeng; Zhang, Xiliang; Zang, Chuncheng; Lu, Zhenwu; Wei, Xiudong

    2010-06-15

    A 4 m x 4 m toroidal heliostat with receiver oriented dual-axis tracking, also called spinning-elevation tracking, was developed as an auxiliary heat source for a hydrogen production system. A series of spinning-elevation tracking formulas have been derived for this heliostat. This included basic tracking formulas, a formula for the elevation angle for heliostat with a mirror-pivot offset, and a more general formula for the biased elevation angle. This paper presents the new tracking formulas in detail and analyzes the accuracy of applying a simplifying approximation. The numerical results show these receiver oriented dual-axis tracking formula approximations are accurate to within 2.5 x 10{sup -6} m in image plane. Some practical tracking strategies are discussed briefly. Solar images from the toroidal heliostat at selected times are also presented. (author)

  17. Sun-Relative Pointing for Dual-Axis Solar Trackers Employing Azimuth and Elevation Rotations

    SciTech Connect

    Riley, Daniel; Hansen, Clifford W.

    2014-12-30

    Dual axis trackers employing azimuth and elevation rotations are common in the field of photovoltaic (PV) energy generation. Accurate sun-tracking algorithms are widely available. However, a steering algorithm has not been available to accurately point the tracker away from the sun such that a vector projection of the sun beam onto the tracker face falls along a desired path relative to the tracker face. We have developed an algorithm which produces the appropriate azimuth and elevation angles for a dual axis tracker when given the sun position, desired angle of incidence, and the desired projection of the sun beam onto the tracker face. Development of this algorithm was inspired by the need to accurately steer a tracker to desired sun-relative positions in order to better characterize the electro-optical properties of PV and CPV modules.

  18. Sun-Relative Pointing for Dual-Axis Solar Trackers Employing Azimuth and Elevation Rotations

    DOE PAGESBeta

    Riley, Daniel; Hansen, Clifford W.

    2014-12-30

    Dual axis trackers employing azimuth and elevation rotations are common in the field of photovoltaic (PV) energy generation. Accurate sun-tracking algorithms are widely available. However, a steering algorithm has not been available to accurately point the tracker away from the sun such that a vector projection of the sun beam onto the tracker face falls along a desired path relative to the tracker face. We have developed an algorithm which produces the appropriate azimuth and elevation angles for a dual axis tracker when given the sun position, desired angle of incidence, and the desired projection of the sun beam ontomore » the tracker face. Development of this algorithm was inspired by the need to accurately steer a tracker to desired sun-relative positions in order to better characterize the electro-optical properties of PV and CPV modules.« less

  19. Confocal fluorescence microscope with dual-axis architecture and biaxial postobjective scanning

    PubMed Central

    Wang, Thomas D.; Contag, Christopher H.; Mandella, Michael J.; Chan, Ning Y.; Kino, Gordon S.

    2007-01-01

    We present a novel confocal microscope that has dual-axis architecture and biaxial postobjective scanning for the collection of fluorescence images from biological specimens. This design uses two low-numerical-aperture lenses to achieve high axial resolution and long working distance, and the scanning mirror located distal to the lenses rotates along the orthogonal axes to produce arc-surface images over a large field of view (FOV). With fiber optic coupling, this microscope can potentially be scaled down to millimeter dimensions via microelectromechanical systems (MEMS) technology. We demonstrate a benchtop prototype with a spatial resolution ≤4.4 μm that collects fluorescence images with a high SNR and a good contrast ratio from specimens expressing GFP. Furthermore, the scanning mechanism produces only small differences in aberrations over the image FOV. These results demonstrate proof of concept of the dual-axis confocal architecture for in vivo molecular and cellular imaging. PMID:15250760

  20. Stochastic dual-plane on-axis digital holographic imaging on irregular surfaces.

    PubMed

    Wang, Fengpeng; Wang, Dayong; Rong, Lu; Wang, Yunxin; Zhao, Jie

    2016-05-10

    An imaging method based on dual-plane on-axis digital holography is proposed for the situation in which an object is on the irregular surface of a transparent medium. Light propagation of the object on the uneven surface of the medium is analyzed and simulated. The diffracted pattern of the object is deformed or destroyed by the refracted light of the medium. Dual-plane on-axis digital holography is used to eliminate the twin image. In order to retrieve the information lost in the reconstructed image due to destructive interference, the object is illuminated by a stochastic beam that is a speckle wave produced by a ground glass. Simulated and experimental results are presented, to demonstrate that the proposed method can be used for imaging on the irregular surface of a transparent medium. PMID:27168284

  1. Mechanical design and force calibration of dual-axis micromechanical probe for friction force microscopy

    NASA Astrophysics Data System (ADS)

    Fukuzawa, Kenji; Terada, Satoshi; Shikida, Mitsuhiro; Amakawa, Hiroaki; Zhang, Hedong; Mitsuya, Yasunaga

    2007-02-01

    A dual-axis micromechanical probe that combines a double cantilever and torsion beams is presented. This probe can reduce the mechanical cross-talk between the lateral and vertical force detections. In addition, dual-axis forces can be detected by measuring the dual-axis displacement of the probe end using the optical lever-based method used in conventional friction force microscopes (FFMs). In this paper, the mechanical design of the probe, the details of the fabrication method, FFM performance, and calibration of the friction force are discussed. The mechanical design and the microfabrication method for probes that can provide a force resolution of the order of 1nN without mechanical cross-talk are presented. Calibration of the lateral force signal is possible by using the relationship between the lateral force and the piezodisplacement at the onset of the probe scanning. The micromechanical probe enables simultaneous and independent detection of atomic and friction forces. This leads to accurate investigation of nanotribological phenomena and visualization of the distribution of the friction properties, which helps the identification of the material properties.

  2. Mechanical design and force calibration of dual-axis micromechanical probe for friction force microscopy

    SciTech Connect

    Fukuzawa, Kenji; Terada, Satoshi; Shikida, Mitsuhiro; Amakawa, Hiroaki; Zhang, Hedong; Mitsuya, Yasunaga

    2007-02-01

    A dual-axis micromechanical probe that combines a double cantilever and torsion beams is presented. This probe can reduce the mechanical cross-talk between the lateral and vertical force detections. In addition, dual-axis forces can be detected by measuring the dual-axis displacement of the probe end using the optical lever-based method used in conventional friction force microscopes (FFMs). In this paper, the mechanical design of the probe, the details of the fabrication method, FFM performance, and calibration of the friction force are discussed. The mechanical design and the microfabrication method for probes that can provide a force resolution of the order of 1 nN without mechanical cross-talk are presented. Calibration of the lateral force signal is possible by using the relationship between the lateral force and the piezodisplacement at the onset of the probe scanning. The micromechanical probe enables simultaneous and independent detection of atomic and friction forces. This leads to accurate investigation of nanotribological phenomena and visualization of the distribution of the friction properties, which helps the identification of the material properties.

  3. Measurement errors induced by axis tilt of biplates in dual-rotating compensator Mueller matrix ellipsometers

    NASA Astrophysics Data System (ADS)

    Gu, Honggang; Zhang, Chuanwei; Jiang, Hao; Chen, Xiuguo; Li, Weiqi; Liu, Shiyuan

    2015-06-01

    Dual-rotating compensator Mueller matrix ellipsometer (DRC-MME) has been designed and applied as a powerful tool for the characterization of thin films and nanostructures. The compensators are indispensable optical components and their performances affect the precision and accuracy of DRC-MME significantly. Biplates made of birefringent crystals are commonly used compensators in the DRC-MME, and their optical axes invariably have tilt errors due to imperfect fabrication and improper installation in practice. The axis tilt error between the rotation axis and the light beam will lead to a continuous vibration in the retardance of the rotating biplate, which further results in significant measurement errors in the Mueller matrix. In this paper, we propose a simple but valid formula for the retardance calculation under arbitrary tilt angle and azimuth angle to analyze the axis tilt errors in biplates. We further study the relations between the measurement errors in the Mueller matrix and the biplate axis tilt through simulations and experiments. We find that the axis tilt errors mainly affect the cross-talk from linear polarization to circular polarization and vice versa. In addition, the measurement errors in Mueller matrix increase acceleratively with the axis tilt errors in biplates, and the optimal retardance for reducing these errors is about 80°. This work can be expected to provide some guidences for the selection, installation and commissioning of the biplate compensator in DRC-MME design.

  4. Shielding design of electron beam stop for Dual-Axis Radiographic Hydrotest Facility (DARHT)

    SciTech Connect

    Brown, T.H.

    1996-03-01

    An electron beam stop was designed to allow workers to be present in the experimental area while the accelerators are producing electron beam pulses. The beam stop is composed of a graphite region to stop the electron pulses and a surrounding tungsten region to attenuate photons produced by electron transport in the graphite. Radiation-transport dose calculations were performed to set the dimensions of the graphite and tungsten regions. To reduce calculational effort, electron transport in the graphite was calculated separately from photon dose transport to worker locations. The source for photon dose transport was generated by tallying photons emerging from the graphite during electron transport.

  5. Photoneutron production in electron beam stop for dual-axis radiographic hydrotest facility (DARHT)

    SciTech Connect

    Chadwick, M.B.; Brown, T.H.; Little, R.C.

    1998-03-01

    A beam stop design for an electron linear accelerator was analyzed from the perspective of photoneutron production and subsequent dose. Sophisticated nuclear data modeling codes were used to generate the photoneutron production cross sections and spectra that were then used in MCNP transport calculations. The resulting neutron dose exceeded limits for workers present in the experimental area while the accelerators are producing electron beam pulses. Therefore, the beam stop was redesigned to limit doses to acceptable values, consistent with the ALARA philosophy.

  6. A dual-axis tilt acquisition geometry for digital musculoskeletal tomosynthesis

    NASA Astrophysics Data System (ADS)

    Levakhina, Yulia M.; Duschka, Robert L.; Vogt, Florian M.; Barkhausen, Joerg; Buzug, Thorsten M.

    2013-07-01

    Digital tomosynthesis (DT) is a limited angle tomographic x-ray technique. It is an attractive low-dose alternative to computed tomography (CT) in many imaging applications. However, the DT dataset is incomplete, which leads to out-of-focus artifacts and limited axial resolution. In this paper, a novel dual-axis tilt acquisition geometry is proposed and evaluated. This geometry solves some issues in tomosynthesis with the traditional scanning geometry by scanning the object with a set of perpendicular arcs. In this geometry the acquisition in the additional perpendicular direction is done using a tiltable object supporting platform. The proposed geometry allows for capturing more singularities of the Radon transform, filling the Fourier space with more data and better approximating the Tuy-Smith conditions. In order to evaluate the proposed system, several studies have been carried out. To validate the simulation setup the performance of the traditional scanning geometry has been simulated and compared to known results from the literature. It has also been shown that the possible improvement of the image quality in the traditional geometry is limited. These limitations can be partially overcome by using the proposed dual-axis tilt geometry. The novel geometry is superior and with the same number of projections better reconstructed images can be obtained. All studies have been made using a software tomosynthesis simulator. A micro-CT reconstruction of a bone has been used as a software phantom. Simultaneous algebraic reconstruction has been used to reconstruct simulated projections. As a conclusion, acquiring data outside the standard arc allows for improving performance of musculoskeletal tomosynthesis. With the proposed dual-axis acquisition geometry a performance gain is achieved without an increase in dose and major modifications to the instrumentation of existing tomosynthesis devices.

  7. A dual-axis tilt acquisition geometry for digital musculoskeletal tomosynthesis.

    PubMed

    Levakhina, Yulia M; Duschka, Robert L; Vogt, Florian M; Barkhausen, Joerg; Buzug, Thorsten M

    2013-07-21

    Digital tomosynthesis (DT) is a limited angle tomographic x-ray technique. It is an attractive low-dose alternative to computed tomography (CT) in many imaging applications. However, the DT dataset is incomplete, which leads to out-of-focus artifacts and limited axial resolution. In this paper, a novel dual-axis tilt acquisition geometry is proposed and evaluated. This geometry solves some issues in tomosynthesis with the traditional scanning geometry by scanning the object with a set of perpendicular arcs. In this geometry the acquisition in the additional perpendicular direction is done using a tiltable object supporting platform. The proposed geometry allows for capturing more singularities of the Radon transform, filling the Fourier space with more data and better approximating the Tuy-Smith conditions. In order to evaluate the proposed system, several studies have been carried out. To validate the simulation setup the performance of the traditional scanning geometry has been simulated and compared to known results from the literature. It has also been shown that the possible improvement of the image quality in the traditional geometry is limited. These limitations can be partially overcome by using the proposed dual-axis tilt geometry. The novel geometry is superior and with the same number of projections better reconstructed images can be obtained. All studies have been made using a software tomosynthesis simulator. A micro-CT reconstruction of a bone has been used as a software phantom. Simultaneous algebraic reconstruction has been used to reconstruct simulated projections. As a conclusion, acquiring data outside the standard arc allows for improving performance of musculoskeletal tomosynthesis. With the proposed dual-axis acquisition geometry a performance gain is achieved without an increase in dose and major modifications to the instrumentation of existing tomosynthesis devices. PMID:23787371

  8. Dual-axis high-data-rate atom interferometer via cold ensemble exchange

    SciTech Connect

    Rakholia, Akash V.; McGuinness, Hayden J.; Biedermann, Grant W.

    2014-11-24

    We demonstrate a dual-axis accelerometer and gyroscope atom interferometer, which can form the building blocks of a six-axis inertial measurement unit. By recapturing the atoms after the interferometer sequence, we maintain a large atom number at high data rates of 50 to 100 measurements per second. Two cold ensembles are formed in trap zones located a few centimeters apart and are launched toward one another. During their ballistic trajectory, they are interrogated with a stimulated Raman sequence, detected, and recaptured in the opposing trap zone. As a result, we achieve sensitivities at μg/ √Hz and μrad/s/ √Hz levels, making this a compelling prospect for expanding the use of atom interferometer inertial sensors beyond benign laboratory environments.

  9. Dual-axis high-data-rate atom interferometer via cold ensemble exchange

    DOE PAGESBeta

    Rakholia, Akash V.; McGuinness, Hayden J.; Biedermann, Grant W.

    2014-11-24

    We demonstrate a dual-axis accelerometer and gyroscope atom interferometer, which can form the building blocks of a six-axis inertial measurement unit. By recapturing the atoms after the interferometer sequence, we maintain a large atom number at high data rates of 50 to 100 measurements per second. Two cold ensembles are formed in trap zones located a few centimeters apart and are launched toward one another. During their ballistic trajectory, they are interrogated with a stimulated Raman sequence, detected, and recaptured in the opposing trap zone. As a result, we achieve sensitivities at μg/ √Hz and μrad/s/ √Hz levels, making thismore » a compelling prospect for expanding the use of atom interferometer inertial sensors beyond benign laboratory environments.« less

  10. Off-Line Programming System of Multi-Axis Platform for Dual Beam Laser Welding

    NASA Astrophysics Data System (ADS)

    Yang, Jian-Zhong; Zhang, Yan; Chen, Ji-Hong; Wang, Wei-Qiang; Liu, Yi

    The multi-axis platform of dual beam laser welding (DBLW) can guarantee a good synchronism on double sides, adaptation and precision, thus it can be widely applied. On this platform, this paper studies critical technology of off-line programming of DBLW. It presents a U-oriented on double sides trajectory planning method based on the traditional method derived from single beam laser welding. Then a calibration strategy of structural parameters is rendered and G codes are produced by a postprocessor. At last the researchers develops the off-line programming system on CAM platforms and a simulation conducted proves the system satisfying the need.

  11. A lightweight high performance dual-axis gimbal for space applications

    SciTech Connect

    Pines, D.J.; Hakala, D.B.; Malueg, R.

    1995-05-05

    This paper describes the design, development and performance of a lightweight precision gimbal with dual-axis slew capability to be used in a closed-loop optical tracking system at Lawrence Livermore National Laboratory-LLNL. The motivation for the development of this gimbal originates from the need to acquire and accurately localize warm objects (T{approximately}500 K) in a cluttered background. The design of the gimbal is centered around meeting the following performance requirements: pointing accuracy with control < 35 {mu}rad-(1-{omega}); slew capability > 0.2 rad/sec; mechanical weight < 5 kg. These performance requirements are derived by attempting to track a single target from multiple satellites in low Earth orbit using a mid-wave infrared camera. Key components in the gimbal hardware that are essential to meeting the performance objectives include a nickel plated beryllium mirro, an accurate lightweight capacitive pickoff device for angular measurement about the elevation axis, a 16-bit coarse/fine resolver for angular measurement about the azimuth axis, a toroidally wound motor with low hysteresis for providing torque about the azimuth axis, and the selection of beryllium parts to insure high stiffness to weight ratios and more efficient thermal conductivity. Each of these elements are discussed in detail to illustrate the design trades performed to meet the tracking and slewing requirements demanded. Preliminary experimental results are also given for various commanded tracking maneuvers.

  12. Radiographic anatomy of the rabbit skull with particular reference to the tympanic bulla and temporomandibular joint: Part 1: Lateral and long axis rotational angles.

    PubMed

    King, A M; Cranfield, F; Hall, J; Hammond, G; Sullivan, M

    2010-11-01

    Radiography is frequently used to investigate otitis media and dental disease in rabbits, although there are few detailed reports regarding the radiographic anatomy of the rabbit skull. The aim of this study was to document rabbit skull radiographic anatomy, with particular reference to the tympanic bulla (TB) and temporomandibular joint (TMJ), and to identify views that allowed optimal assessment of these areas. Equipment was used that allowed repeatable positioning of skulls at known rotational angles in lateral (lateral to rostrocaudal) and long axis (lateral to ventrodorsal) directions. The views were repeated with lead markers attached to anatomical features and cadaver heads. The TB could be best examined between 30° and 60° in both planes. The TMJ was best visualised between 70° and 90° in a lateral direction, particularly along a true rostrocaudal plane, but could not be imaged well at any of the long axis rotational angles. Similar images were obtained using cadavers. PMID:19853482

  13. Biodynamic response of the seated human body to single-axis and dual-axis vibration: effect of backrest and non-linearity.

    PubMed

    Qiu, Yi; Griffin, Michael J

    2012-01-01

    The biodynamic responses to the human body give an understanding of why human responses to vibration (changes in health, comfort, and performance) vary with the frequency and direction of vibration. Studies have shown that biodynamic responses also vary with the magnitude of vibration and that the backrests of seats influence the transmission of vibration to the seated human body. There has been little study of the nonlinearity in the biodynamic responses of the body to dual-axis excitation and no study of the influence of backrests during dual-axis excitation. This study investigated the apparent mass and cross-axis apparent mass of the human body exposed to random vibration (0.2 to 20 Hz) in all 15 possible combinations of four magnitudes (0, 0.25, 0.5 and 1.0 ms(-2) r.m.s.) of fore-and-aft vibration and the same four magnitudes of vertical vibration. Nonlinearity was evident, with the body softening with increasing magnitude of vibration when using a fixed magnitude of vibration in one direction and varying the magnitude of vibration in the other direction. The fore-and-aft apparent mass on the seat was greater without a backrest at the lower frequencies but greater with a backrest at the higher frequencies. The vertical apparent mass on the seat was decreased by the backrest at low frequencies. Cross-axis coupling was evident, with excitation in one axis producing a response in the other axis. It is concluded that the nonlinearity of the body evident during single-axis and multi-axis vibration, and the influence of backrests, should be taken into account when determining frequency weightings for predicting human responses to vibration and when optimising the dynamics of seating to minimise exposure to vibration. PMID:22146145

  14. Vocalization removal for improved automatic segmentation of dual-axis swallowing accelerometry signals.

    PubMed

    Sejdić, Ervin; Falk, Tiago H; Steele, Catriona M; Chau, Tom

    2010-07-01

    Automatic segmentation of dual-axis swallowing accelerometry signals can be severely affected by strong vocalizations. In this paper, a method based on periodicity detection is proposed to detect and remove such vocalizations. Periodic signal components are detected using conventional speech processing techniques and information from both axes are combined to improve vocalization detection accuracy. Experiments with 408 healthy subjects performing dry, wet, and wet chin tuck swallows show that the proposed method attains an average 95.3% sensitivity and 96.3% specificity. When applied in conjunction with an automatic segmentation algorithm, it is observed that segmentation accuracy improves by approximately 55%. These results encourage further development of medical devices for the detection of swallowing difficulties. PMID:20483652

  15. A Three-Axis Force Sensor for Dual Finger Haptic Interfaces

    PubMed Central

    Fontana, Marco; Marcheschi, Simone; Salsedo, Fabio; Bergamasco, Massimo

    2012-01-01

    In this work we present the design process, the characterization and testing of a novel three-axis mechanical force sensor. This sensor is optimized for use in closed-loop force control of haptic devices with three degrees of freedom. In particular the sensor has been conceived for integration with a dual finger haptic interface that aims at simulating forces that occur during grasping and surface exploration. The sensing spring structure has been purposely designed in order to match force and layout specifications for the application. In this paper the design of the sensor is presented, starting from an analytic model that describes the characteristic matrix of the sensor. A procedure for designing an optimal overload protection mechanism is proposed. In the last part of the paper the authors describe the experimental characterization and the integrated test on a haptic hand exoskeleton showing the improvements in the controller performances provided by the inclusion of the force sensor. PMID:23202012

  16. A dual-loop model of the human controller in single-axis tracking tasks

    NASA Technical Reports Server (NTRS)

    Hess, R. A.

    1977-01-01

    A dual loop model of the human controller in single axis compensatory tracking tasks is introduced. This model possesses an inner-loop closure which involves feeding back that portion of the controlled element output rate which is due to control activity. The sensory inputs to the human controller are assumed to be system error and control force. The former is assumed to be sensed via visual, aural, or tactile displays while the latter is assumed to be sensed in kinesthetic fashion. A nonlinear form of the model is briefly discussed. This model is then linearized and parameterized. A set of general adaptive characteristics for the parameterized model is hypothesized. These characteristics describe the manner in which the parameters in the linearized model will vary with such things as display quality. It is demonstrated that the parameterized model can produce controller describing functions which closely approximate those measured in laboratory tracking tasks for a wide variety of controlled elements.

  17. Attitude Heading Reference System Using MEMS Inertial Sensors with Dual-Axis Rotation

    PubMed Central

    Kang, Li; Ye, Lingyun; Song, Kaichen; Zhou, Yang

    2014-01-01

    This paper proposes a low cost and small size attitude and heading reference system based on MEMS inertial sensors. A dual-axis rotation structure with a proper rotary scheme according to the design principles is applied in the system to compensate for the attitude and heading drift caused by the large gyroscope biases. An optimization algorithm is applied to compensate for the installation angle error between the body frame and the rotation table's frame. Simulations and experiments are carried out to evaluate the performance of the AHRS. The results show that the proper rotation could significantly reduce the attitude and heading drifts. Moreover, the new AHRS is not affected by magnetic interference. After the rotation, the attitude and heading are almost just oscillating in a range. The attitude error is about 3° and the heading error is less than 3° which are at least 5 times better than the non-rotation condition. PMID:25268911

  18. Investigating gecko setae adhesion using a dual-axis MEMS force sensor

    NASA Astrophysics Data System (ADS)

    Hill, Ginel; Soto, Daniel; Peattie, Anne; Full, Robert; Kenny, Thomas

    2007-03-01

    A dual-axis piezoresistive MEMS force sensor was used to investigate the role of orientation angle on the adhesion of gecko hairs, called setae. Made of keratin with nanoscale features, gecko setae are a spectacular, robust dry adhesive with anisotropic adhesion properties. A wealth of recent research has been devoted to synthetic mimicry of the gecko seta. However, most synthetics do not yet display anisotropic adhesion, which is critical for controllable attachment and release. Previous research using a wire gauge tested the role of the pitch angle between the stalk of natural setae and the substrate and found a dramatic cutoff angle of 30^o, above which setae detach from the substrate [1]. The present work details the effect of the ``roll'' angle on natural setae adhesion. [1] K. Autumn, et al. Nature, 405: 681 (2000).

  19. DARHT AXIS II Beam Position Monitors

    SciTech Connect

    Johnson, Jeff; Ekdahl, Carl; Broste, William

    2004-11-10

    One of Los Alamos National Laboratory's (LANL's) primary responsibilities for national security is to certify the readiness of our nation's nuclear stockpile. Since the end of underground testing in 1994, LANL has used non-nuclear experiments and computational models to certify our stockpile. The Dual Axis Radiographic Hydrodynamic Test (DARHT) Facility is the next tool scientists will utilize for stockpile certification. DARHT will soon be capable of producing a three dimensional, time resolved radiographic image of a nuclear weapon pit during implosion. Data from these radiographic images will be used to validate the computational models used to study nuclear weapons. The first axis of DARHT with its single-pulse capability has been in use for about 2 years. Data returned from DARHT's First axis has been exceptional, producing the highest resolution radiographic image ever for a pit test.

  20. DARHT AXIS II Beam Position Monitors

    NASA Astrophysics Data System (ADS)

    Johnson, Jeff; Ekdahl, Carl; Broste, William

    2004-11-01

    One of Los Alamos National Laboratory's (LANL's) primary responsibilities for national security is to certify the readiness of our nation's nuclear stockpile. Since the end of underground testing in 1994, LANL has used non-nuclear experiments and computational models to certify our stockpile. The Dual Axis Radiographic Hydrodynamic Test (DARHT) Facility is the next tool scientists will utilize for stockpile certification. DARHT will soon be capable of producing a three dimensional, time resolved radiographic image of a nuclear weapon pit during implosion. Data from these radiographic images will be used to validate the computational models used to study nuclear weapons. The first axis of DARHT with its single-pulse capability has been in use for about 2 years. Data returned from DARHT's First axis has been exceptional, producing the highest resolution radiographic image ever for a pit test.

  1. Development of a MEMS dual-axis differential capacitance floating element shear stress sensor

    SciTech Connect

    Barnard, Casey; Griffin, Benjamin

    2015-09-01

    A single-axis MEMS wall shear stress sensor with differential capacitive transduction method is produced. Using a synchronous modulation and demodulation interface circuit, the system is capable of making real time measurements of both mean and fluctuating wall shear stress. A sensitivity of 3.44 mV/Pa is achieved, with linearity in response demonstrated up to testing limit of 2 Pa. Minimum detectable signals of 340 μPa at 100 Hz and 120 μPa at 1 kHz are indicated, with a resonance of 3.5 kHz. Multiple full scale wind tunnel tests are performed, producing spectral measurements of turbulent boundary layers in wind speeds ranging up to 0.5 Ma (18 Pa of mean wall shear stress). The compact packaging allows for minimally invasive installation, and has proven relatively robust over multiple testing events. Temperature sensitivity, likely due to poor CTE matching of packaged materials, is an ongoing concern being addressed. These successes are being directly leveraged into a development plan for a dual-axis wall shear stress sensor, capable of producing true vector estimates at the wall.

  2. Method of moments analysis of displaced-axis dual reflector antennas

    NASA Astrophysics Data System (ADS)

    Vered, Nissan

    1992-03-01

    Small symmetric dual reflector antennas suffer from low efficiency due to subreflector blockage of the main reflector and subreflector scattering. These can be reduced by slicing the main dish and translating its rotational axis, along with modifying the subreflector geometry. This type of design is usually applied to low-frequency reflectors, but high-frequency analysis techniques are used. Consequently the agreement between measured and computed data is not good as it would be for rigorous solution such as the method of moments. This thesis modifies an existing method of moments computer code to handle the displaced axis geometry, and computes the radiation pattern and the efficiency of this antenna as a function of geometrical and electrical design parameters. Optimum configurations are identified for several feed types. The paraboloidal antenna with a feed at the focus does not allow much control of the power distribution over the aperture surface, except for what can be accomplished by changing the focal length and feed pattern.

  3. Problems Encountered During the Recertification of the GLORY Solar Array Dual Axis Gimbal Drive Actuators

    NASA Technical Reports Server (NTRS)

    Saltzman, Marc; Schepis, Jospeh P.; Bruckner, Michael J.

    2009-01-01

    The Glory observatory is the current incarnation of the Vegetation Canopy Lidar (VCL) mission spacecraft bus. The VCL spacecraft bus, having been cancelled for programmatic reasons in 2000, was nearly integrated when it was put into storage for possible future use. The Glory mission was a suitable candidate for using this spacecraft and in 2006 an effort to recertify the two axis solar array gimbal drive after its extended storage was begun. What was expected to be a simple performance validation of the two dual axis gimbal stepper motors became a serious test, diagnosis and repair task once questions arose on the flight worthiness of the hardware. A significant test program logic flow was developed which identified decisions that could be made based on the results of individual recertification tests. Without disassembling the bi-axial gimbals, beginning with stepper motor threshold voltage measurements and relating these to powered drive torque measurements, both performed at the spacecraft integrator s facility, a confusing picture of the health of the actuators came to light. Tests at the gimbal assembly level and tests of the disassembled actuators were performed by the manufacturer to validate our results and torque discrepancies were noted. Further disassembly to the component level of the actuator revealed the source of the torque loss.

  4. Dual-waveband MWIR/visible three-axis stabilized sensor suite for submarine optronics masts

    NASA Astrophysics Data System (ADS)

    Armstrong, George R.

    1998-10-01

    A dual-band MWIR/Visible Electro-Optic sensor suite has been developed for use in the CM010 family of Optronics Masts, currently being evolved by Pilkington Optronics for the Royal Navy's new Astute Class submarines. The sensor suite features a medium wave IR thermal imaging camera and a broadcast standard color TV camera, both of which view the scene through a common sapphire pressure window. Three-axis stabilization is provided for both sensors, in which pitch and yaw are controlled by a common line-of-sight prism behind the sensor window, while control of roll about the line of sight is achieved by individual optical derotators within the TI and visible band optics. Precision stabilized control is provided in both the MWIR and visible optical chains. The MWIR sensor consists of a diagonally-microscanned 320 X 240 focal plane, the microscan beam deflection being carried out by the TI piezo mirror. The visible sensor, designed for daylight use, consists of three 1024 X 1024 pixel frame transfer CCD focal planes, which in conjunction with variable neutral density filters yield excellent performance over a 103 dynamic range of daylight scene illuminance. Both optical systems provide Fields of View of 3, 6 and 24 degrees, and a Field of Regard covering from -15 degrees in depression to +60 degrees in elevation. Field of view switching is carried out by dual-band afocal optics situated in the common optical path. A 'Quick Look Round' mode allows both sensors to capture imagery through a full 360 degree azimuth sweep for subsequent analysis, with minimal mast exposure time.

  5. Calcification content quantification by dual-energy x-ray absorptiometry with a 2D digital radiographic detector

    NASA Astrophysics Data System (ADS)

    Dinten, Jean M.; Robert-Coutant, Christine; Darboux, Michel; Gonon, Georges; Bordy, Thomas

    2003-06-01

    In a previous paper (SPIE Medical Imaging 2001), a dual energy method for bone densitometry using a 2D digital radiographic detector has been presented. In this paper, calcium content quantification performance of the approach is precised. The main challenge is to achieve quantification using scatter-corrected dual energy acquisitions. Therefore a scatter estimation approach, based on an expression of scatter as a functional of the primary flux, has been developed. This expression is derived from the Klein and Nishina equation and includes tabulated scatter level values. The calcium quantification performances are validated on two configurations. A first one is issued from criteria developed by the French "Groupe de Recherche et d'Information sur les Osteoporoses." It is based on the use of a phantom made of five 3mm thick PVC sheets in the form of five steps, representing five different bone mineral density values, included in a lucite container filled with water. Additional lucite plates can be put over the phantom. This phantom has been used for evaluation of quantification robustness versus patient thickness and composition variations, and for accuracy evaluation. The second configuration, composed of small calcified objects (representative of lung nodules), is used for evaluating capacities to differentiate calcified from non calcified nodules and to test calcium content quantification performance.

  6. Construction of a dual axis force reflection stick and test station

    NASA Astrophysics Data System (ADS)

    Repperger, Daniel E.; Scarborough, Eric L.; Chelette, Tamara L.

    1991-11-01

    This report describes the construction of a dual axis force reflecting stick controller and test station which was constructed through the use of basic research funds (ILIR monies). The prototype described in this report is powered only by electric motors and used the latest technology in computers. This was an advancement over a previous prototype which involved pneumatic devices and was very large, bulky, and awkward to use. An experiment was conducted with 5 subjects as described herein to test the overall system for its use in experimental design. The motivation for developing such a small test station for the use of force reflection in stick controllers is because with this new compact and portable system, many new applications now appear for this technology. The system described herein minimizes both weight and electric power requirements to produce the same force reflection. By upgrading the technology in the components used in this test station, wider use of force reflection is now available for a host of new applications.

  7. High mobility, dual layer, c-axis aligned crystalline/amorphous IGZO thin film transistor

    NASA Astrophysics Data System (ADS)

    Chung, Chen-Yang; Zhu, Bin; Greene, Raymond G.; Thompson, Michael O.; Ast, Dieter G.

    2015-11-01

    We demonstrate a dual layer IGZO thin film transistor (TFT) consisting of a 310 °C deposited c-axis aligned crystal (CAAC) 20 nm thick channel layer capped by a second, 30 nm thick, 260 °C deposited amorphous IGZO layer. The TFT exhibits a saturation field-effect mobility of ˜20 cm2/V s, exceeding the mobility of 50 nm thick single layer reference TFTs fabricated with either material. The deposition temperature of the second layer influences the mobility of the underlying transport layer. When the cap layer is deposited at room temperature (RT), the mobility in the 310 °C deposited CAAC layer is initially low (6.7 cm2/V s), but rises continuously with time over 58 days to 20.5 cm2/V s, i.e., to the same value as when the second layer is deposited at 260 °C. This observation indicates that the two layers equilibrate at RT with a time constant on the order of 5 × 106 s. An analysis based on diffusive transport indicates that the room temperature diffusivity must be of the order of 1 × 10-18 cm2 s-1 with an activation enthalpy EA < 0.2 eV for the mobility limiting species. The findings are consistent with a hypothesis that the amorphous layer deposited on top of the CAAC has a higher solubility for impurities and/or structural defects than the underlying nanocrystalline transport layer, and that the equilibration of the mobility limiting species is rate limited by hydrogen diffusion, whose known diffusivity fits these estimates.

  8. A feasibility study of stationary and dual-axis tracking grid-connected photovoltaic systems in the Upper Midwest

    NASA Astrophysics Data System (ADS)

    Warren, Ryan Duwain

    Three primary objectives were defined for this work. The first objective was to determine, assess, and compare the performance, heat transfer characteristics, economics, and feasibility of real-world stationary and dual-axis tracking grid-connected photovoltaic (PV) systems in the Upper Midwest. This objective was achieved by installing two grid-connected PV systems with different mounting schemes in central Iowa, implementing extensive data acquisition systems, monitoring operation of the PV systems for one full year, and performing detailed experimental performance and economic studies. The two PV systems that were installed, monitored, and analyzed included a 4.59 kWp roof-mounted stationary system oriented for maximum annual energy production, and a 1.02 kWp pole-mounted actively controlled dual-axis tracking system. The second objective was to demonstrate the actual use and performance of real-world stationary and dual-axis tracking grid-connected PV systems used for building energy generation applications. This objective was achieved by offering the installed PV systems to the public for demonstration purposes and through the development of three computer-based tools: a software interface that has the ability to display real-time and historical performance and meteorological data of both systems side-by-side, a software interface that shows real-time and historical video and photographs of each system, and a calculator that can predict performance and economics of stationary and dual-axis tracking grid-connected PV systems at various locations in the United States. The final objective was to disseminate this work to social, professional, scientific, and academic communities in a way that is applicable, objective, accurate, accessible, and comprehensible. This final objective will be addressed by publishing the results of this work and making the computer-based tools available on a public website (www.energy.iastate.edu/Renewable/solar). Detailed experimental

  9. Generalized DQE analysis of radiographic and dual-energy imaging using flat-panel detectors

    SciTech Connect

    Richard, S.; Siewerdsen, J.H.; Jaffray, D.A.; Moseley, D.J.; Bakhtiar, B.

    2005-05-01

    Analysis of detective quantum efficiency (DQE) is an important component of the investigation of imaging performance for flat-panel detectors (FPDs). Conventional descriptions of DQE are limited, however, in that they take no account of anatomical noise (i.e., image fluctuations caused by overlying anatomy), even though such noise can be the most significant limitation to detectability, often outweighing quantum or electronic noise. We incorporate anatomical noise in experimental and theoretical descriptions of the 'generalized DQE' by including a spatial-frequency-dependent noise-power term, S{sub B}, corresponding to background anatomical fluctuations. Cascaded systems analysis (CSA) of the generalized DQE reveals tradeoffs between anatomical noise and the factors that govern quantum noise. We extend such analysis to dual-energy (DE) imaging, in which the overlying anatomical structure is selectively removed in image reconstructions by combining projections acquired at low and high kVp. The effectiveness of DE imaging in removing anatomical noise is quantified by measurement of S{sub B} in an anthropomorphic phantom. Combining the generalized DQE with an idealized task function to yield the detectability index, we show that anatomical noise dramatically influences task-based performance, system design, and optimization. For the case of radiography, the analysis resolves a fundamental and illustrative quandary: The effect of kVp on imaging performance, which is poorly described by conventional DQE analysis but is clarified by consideration of the generalized DQE. For the case of DE imaging, extension of a generalized CSA methodology reveals a potentially powerful guide to system optimization through the optimal selection of the tissue cancellation parameter. Generalized task-based analysis for DE imaging shows an improvement in the detectability index by more than a factor of 2 compared to conventional radiography for idealized detection tasks.

  10. Vertical and dual-axis vibration of the seated human body: Nonlinearity, cross-axis coupling, and associations between resonances in transmissibility and apparent mass

    NASA Astrophysics Data System (ADS)

    Zheng, Guangtai; Qiu, Yi; Griffin, Michael J.

    2012-12-01

    The vertical apparent mass of the human body exhibits nonlinearity, with the principal resonance frequency reducing as the vibration magnitude increases. Measures of the transmission of vibration to the spine and the pelvis have suggested complex modes are responsible for the dominant resonance during vertical excitation, but the modes present with dual-axis excitation have not been investigated. This study was designed to examine how the apparent mass and transmissibility of the human body depend on the magnitude of vertical excitation and the addition of fore-and-aft excitation, and the relation between the apparent mass and the transmissibility of the body. The movement of the body (over the first, fifth and twelfth thoracic vertebrae, the third lumbar vertebra, and the pelvis) in the fore-and-aft and vertical directions (and in pitch at the pelvis) was measured in 12 male subjects sitting with their hands on their laps during random vertical vibration excitation (over the range 0.25-20 Hz) at three vibration magnitudes (0.25, 0.5 and 1.0 m s-2 rms). At the highest magnitude of vertical excitation (1.0 m s-2 rms) the effect of adding fore-aft vibration (at 0.25, 0.5, and 1.0 m s-2 rms) was investigated. The forces in the vertical and fore-and-aft directions on the seat surface were also measured so as to calculate apparent masses. Resonances in the apparent mass and transmissibility to the spine and pelvis in the fore-and-aft and vertical directions, and pitch transmissibility to the pelvis, shifted to lower frequencies as the magnitude of vertical excitation increased and as the magnitude of the additional fore-and-aft excitation increased. The nonlinear resonant behaviour of the apparent mass and transmissibility during dual-axis vibration excitation suggests coupling between the principal mode associated with vertical excitation and the cross-axis influence of fore-and-aft excitation. The transmissibility measures are consistent with complex modes

  11. A novel path generation method of onsite 5-axis surface inspection using the dual-cubic NURBS representation

    NASA Astrophysics Data System (ADS)

    Li, Wen-long; Wang, Gang; Zhang, Gang; Pang, Chang-tao; Yin, Zhou-pin

    2016-09-01

    Onsite surface inspection with a touch probe or a laser scanner is a promising technique for efficiently evaluating surface profile error. The existing work of 5-axis inspection path generation bears a serious drawback, however, as there is a drastic orientation change of the inspection axis. Such a sudden change may exceed the stringent physical limit on the speed and acceleration of the rotary motions of the machine tool. In this paper, we propose a novel path generation method for onsite 5-axis surface inspection. The accessibility cones are defined and used to generate alternative interference-free inspection directions. Then, the control points are optimally calculated to obtain the dual-cubic non-Uniform rational B-splines (NURBS) curves, which respectively determine the path points and the axis vectors in an inspection path. The generated inspection path is smooth and non-interference, which deals with the ‘mutation and shake’ problems and guarantees a stable speed and acceleration of machine tool rotary motions. Its feasibility and validity is verified by the onsite inspection experiments of impeller blade.

  12. Miniature in vivo MEMS-based line-scanned dual-axis confocal microscope for point-of-care pathology

    PubMed Central

    Yin, C.; Glaser, A.K.; Leigh, S. Y.; Chen, Y.; Wei, L.; Pillai, P. C. S.; Rosenberg, M. C.; Abeytunge, S.; Peterson, G.; Glazowski, C.; Sanai, N.; Mandella, M. J.; Rajadhyaksha, M.; Liu, J. T. C.

    2016-01-01

    There is a need for miniature optical-sectioning microscopes to enable in vivo interrogation of tissues as a real-time and noninvasive alternative to gold-standard histopathology. Such devices could have a transformative impact for the early detection of cancer as well as for guiding tumor-resection procedures. Miniature confocal microscopes have been developed by various researchers and corporations to enable optical sectioning of highly scattering tissues, all of which have necessitated various trade-offs in size, speed, depth selectivity, field of view, resolution, image contrast, and sensitivity. In this study, a miniature line-scanned (LS) dual-axis confocal (DAC) microscope, with a 12-mm diameter distal tip, has been developed for clinical point-of-care pathology. The dual-axis architecture has demonstrated an advantage over the conventional single-axis confocal configuration for reducing background noise from out-of-focus and multiply scattered light. The use of line scanning enables fast frame rates (16 frames/sec is demonstrated here, but faster rates are possible), which mitigates motion artifacts of a hand-held device during clinical use. We have developed a method to actively align the illumination and collection beams in a DAC microscope through the use of a pair of rotatable alignment mirrors. Incorporation of a custom objective lens, with a small form factor for in vivo clinical use, enables our device to achieve an optical-sectioning thickness and lateral resolution of 2.0 and 1.1 microns respectively. Validation measurements with reflective targets, as well as in vivo and ex vivo images of tissues, demonstrate the clinical potential of this high-speed optical-sectioning microscopy device. PMID:26977337

  13. Dual-core photonic crystal fiber Doppler velocimeter for small horizontal axis wind turbine blade rotational speed measurement

    NASA Astrophysics Data System (ADS)

    Huang, Xue-Feng; Li, Sheng-Ji; Wang, Wei-Chih

    2014-03-01

    The blades are crucial components of a wind turbine, and its steady and reliable operation is directly related to the power output. Thus, condition monitoring and fault diagnosis of the wind turbine blades is highly beneficial to the operational cost. This paper presents a study of small horizontal axis wind turbine blade rotational speed measurement by laser Doppler velocimeter based on dual-core photonic crystal fiber (DC-PCF). The theory on the DC-PCF Doppler velocimeter is presented, and the measurement system is designed and tested. Experimental results show that the DC-PCF Doppler velocimeter has been proved to work successfully. The uncertainty of the rotational speed is about 0 ~ 4 rpm. The accuracy can meet the requirements for monitoring the rotational operation of the wind turbine.

  14. Dynamic characterization and modelling of a dual-axis beam steering device for performance understanding, optimization and control design

    NASA Astrophysics Data System (ADS)

    Berglund, Martin; Palmer, Kristoffer; Lotfi, Sara; Kratz, Henrik; Thornell, Greger

    2013-04-01

    This paper presents a lumped thermal model of a dual-axis laser micromirror device for beam steering in a free-space optical (FSO) communication system, designed for fractionated spacecraft. An FSO communication system provides several advantages, such as larger bandwidth, smaller size and weight of the communication payload and less power consumption. A dual-axis mirror device is designed and realized using microelectromechanical systems technology. The fabrication is based on a double-sided, bulk micromachining process, where the mirror actuates thermally by joints consisting of v-grooves filled with the SU-8 polymer. The size of the device, consisting of a mirror, which is deflectable versus its frame in one direction, and through deflection of the frame in the other, is 15.4 × 10.4 × 0.3 mm3. In order to further characterize and understand the micromirror device, a Simulink state-space model of the actuator is set up using thermal and mechanical properties from a realized actuator. A deviation of less than 2% between the modelled and measured devices was obtained in an actuating temperature range of 20-200 °C. The model of the physical device was examined by evaluating its performance in vacuum, and by changing physical parameters, such as thickness and material composition. By this, design parameters were evaluated for performance gain and usability. For example, the crosstalk between the two actuators deflecting the mirror along its two axes in atmospheric pressure is projected to go down from 97% to 6% when changing the frame material from silicon to silicon dioxide. A feedback control system was also designed around the model in order to examine the possibility to make a robust control system for the physical device. In conclusion, the model of the actuator presented in this paper can be used for further understanding and development of the actuator system.

  15. Small animal bone density and morphometry analysis with a dual energy x-ray absorptiometry bone densitometer using a 2D digital radiographic detector

    NASA Astrophysics Data System (ADS)

    Boudousq, V.; Bordy, T.; Gonon, G.; Dinten, J. M.

    2005-04-01

    The LEXXOS (DMS, Montpellier, France) is the first axial and total body cone beam bone densitometer using a 2D digital radiographic detector. Technical principles and performances for BMD measurements have been presented in previous papers. Bone densitometers are also used on small animals for drug development. In this paper, we show how the LEXXOS system can be adapted to small animals examinations, and its performances are evaluated. At first, in order to take advantage of the whole area of the digital flat panel X-ray detector, the geometrical configuration has been adapted. Secondly, as small animals present low BMD, a specific dual energy calibration has been defined. This adapted system has then been evaluated on two sets of mice: six reference mice and six ovariectomized mice. Each month, these two populations have been examined and the total body BMD has been measured. This evaluation has shown that the right order of BMD magnitude has been obtained and, as expected, BMD increases on the two sets until age of puberty and after this period, decreases significantly for the ovariectomized set. Moreover, the bone image obtained by dual energy processing on LEXXOS presents a radiographic image quality providing with useful complementary information on bone morphometry and architecture.

  16. Qualification of a High Accuracy Dual-Axis Antenna Deployment and Trimming Mechanism

    NASA Technical Reports Server (NTRS)

    Gossant, Alain; Morichon, Francois

    2010-01-01

    The Antenna Deployment and Trimming Mechanism Mark 2 (ADTM Mk2) has been developed to answer today's need for a generic antenna deployment and high accuracy pointing mechanism, allowing RF sensing applications and easier dual deployments configurations. This paper presents the design and evolution from its predecessor, the experience of the design team from kick off to qualification and batch manufacture, as well as some lessons learned from ramping up "mass-production" capabilities while implementing customer driven changes. Astrium has manufactured and flown ADTM units for the past 20 years, from an initial deployment-only mechanism developed for the Orion program to today's Eurostar E3000 ADTM family. The Antenna ADTM Mk2 is an evolution of the original ADTM Mk1. Although it uses Mk1 building blocks to minimize risks associated with the development of a new product, it incorporates major evolutions and is the new baseline for Astrium latest generation of Eurostar E3000 telecom satellites.

  17. First faint dual-field off-axis observations in optical long baseline interferometry

    SciTech Connect

    Woillez, J.; Wizinowich, P.; Ragland, S.; Akeson, R.; Millan-Gabet, R.; Colavita, M.; Eisner, J.; Monnier, J. D.; Pott, J.-U.

    2014-03-10

    Ground-based long baseline interferometers have long been limited in sensitivity in part by the short integration periods imposed by atmospheric turbulence. The first observation fainter than this limit was performed on 2011 January 22 when the Keck Interferometer observed a K = 11.5 target, about 1 mag fainter than its K = 10.3 atmospherically imposed limit; the currently demonstrated limit is K = 12.5. These observations were made possible by the Dual-Field Phase-Referencing (DFPR) instrument, part of the NSF-funded ASTrometry and phase-Referenced Astronomy project; integration times longer than the turbulence time scale are made possible by its ability to simultaneously measure the real-time effects of the atmosphere on a nearby bright guide star and correct for it on the faint target. We present the implementation of DFPR on the Keck Interferometer. Then, we detail its on-sky performance focusing on the accuracy of the turbulence correction and the resulting fringe contrast stability.

  18. A dual-axis pointing mirror with moving-magnet actuation

    NASA Astrophysics Data System (ADS)

    Ataman, Çağlar; Lani, Sébastien; Noell, Wilfried; de Rooij, Nico

    2013-02-01

    A large-aperture and large-angle MEMS-based 2D pointing mirror is presented. The device is electromagnetically actuated by a moving-magnet/stationary-coil pair and potentially suited for high power laser beam shaping and beam pointing applications, such as LIDAR. The 4×4 mm2 mirror, the radially symmetric compliant membrane, and the off-the-shelf permanent magnet are manually assembled, with the planar coil kept at a well-defined vertical distance from the permanent magnet by simple alignment pins. The mirror and the compliant membrane structures are separately microfabricated on bulk silicon and SOI wafers, respectively. The hybrid integration of microfabricated and off-the-shelf components enable low-risk/high-yield fabrication, while limiting the throughput. The device features minimum inter-axis cross coupling and good linearity and is highly immune to alignment and assembly imperfections, thanks to the robust actuation principle. All the components including the bi-axial electromagnetic actuator provide a device footprint as small as the top mirror, allowing the design to be used in compact and high-fill-factor mirror arrays. With a drive coil of 400 mA and 5.12 W drive power, the total uniaxial dc rotation exceeds ±16° (optical) for both axes with good decoupling. At maximum measured angle (biaxial 10° (mechanical)), a position stability better than 0.05° over 7 h, and a position repeatability of 0.04° over 5000 switching cycles is reported. Thermally, the simulated mirror temperature increases to 64 K above the heat sink temperature with a thermal in-flux of 1 kW m-2, under absolute vacuum.

  19. Gabor-domain optical coherence microscopy with integrated dual-axis MEMS scanner for fast 3D imaging and metrology

    NASA Astrophysics Data System (ADS)

    Canavesi, Cristina; Cogliati, Andrea; Hayes, Adam; Santhanam, Anand P.; Tankam, Patrice; Rolland, Jannick P.

    2015-10-01

    Fast, robust, nondestructive 3D imaging is needed for characterization of microscopic structures in industrial and clinical applications. A custom micro-electromechanical system (MEMS)-based 2D scanner system was developed to achieve 55 kHz A-scan acquisition in a Gabor-domain optical coherence microscopy (GD-OCM) instrument with a novel multilevel GPU architecture for high-speed imaging. GD-OCM yields high-definition volumetric imaging with dynamic depth of focusing through a bio-inspired liquid lens-based microscope design, which has no moving parts and is suitable for use in a manufacturing setting or in a medical environment. A dual-axis MEMS mirror was chosen to replace two single-axis galvanometer mirrors; as a result, the astigmatism caused by the mismatch between the optical pupil and the scanning location was eliminated and a 12x reduction in volume of the scanning system was achieved. Imaging at an invariant resolution of 2 μm was demonstrated throughout a volume of 1 × 1 × 0.6 mm3, acquired in less than 2 minutes. The MEMS-based scanner resulted in improved image quality, increased robustness and lighter weight of the system - all factors that are critical for on-field deployment. A custom integrated feedback system consisting of a laser diode and a position-sensing detector was developed to investigate the impact of the resonant frequency of the MEMS and the driving signal of the scanner on the movement of the mirror. Results on the metrology of manufactured materials and characterization of tissue samples with GD-OCM are presented.

  20. High precision dual-axis tracking solar wireless charging system based on the four quadrant photoelectric sensor

    NASA Astrophysics Data System (ADS)

    Liu, Zhilong; Wang, Biao; Tong, Weichao

    2015-08-01

    This paper designs a solar automatic tracking wireless charging system based on the four quadrant photoelectric sensor. The system track the sun's rays automatically in real time to received the maximum energy and wireless charging to the load through electromagnetic coupling. Four quadrant photoelectric sensor responsive to the solar spectrum, the system could get the current azimuth and elevation angle of the light by calculating the solar energy incident on the sensor profile. System driver the solar panels by the biaxial movement mechanism to rotate and tilt movement until the battery plate and light perpendicular to each other. Maximize the use of solar energy, and does not require external power supply to achieve energy self-sufficiency. Solar energy can be collected for portable devices and load wireless charging by close electromagnetic field coupling. Experimental data show that: Four quadrant photoelectric sensor more sensitive to light angle measurement. when track positioning solar light, Azimuth deviation is less than 0.8°, Elevation angle deviation is less than 0.6°. Use efficiency of a conventional solar cell is only 10% -20%.The system uses a Four quadrant dual-axis tracking to raise the utilization rate of 25% -35%.Wireless charging electromagnetic coupling efficiency reached 60%.

  1. Video-rate in vivo fluorescence imaging with a line-scanned dual-axis confocal microscope

    NASA Astrophysics Data System (ADS)

    Chen, Ye; Wang, Danni; Khan, Altaz; Wang, Yu; Borwege, Sabine; Sanai, Nader; Liu, Jonathan T. C.

    2015-10-01

    Video-rate optical-sectioning microscopy of living organisms would allow for the investigation of dynamic biological processes and would also reduce motion artifacts, especially for in vivo imaging applications. Previous feasibility studies, with a slow stage-scanned line-scanned dual-axis confocal (LS-DAC) microscope, have demonstrated that LS-DAC microscopy is capable of imaging tissues with subcellular resolution and high contrast at moderate depths of up to several hundred microns. However, the sensitivity and performance of a video-rate LS-DAC imaging system, with low-numerical aperture optics, have yet to be demonstrated. Here, we report on the construction and validation of a video-rate LS-DAC system that possesses sufficient sensitivity to visualize fluorescent contrast agents that are topically applied or systemically delivered in animal and human tissues. We present images of murine oral mucosa that are topically stained with methylene blue, and images of protoporphyrin IX-expressing brain tumor from glioma patients that have been administered 5-aminolevulinic acid prior to surgery. In addition, we demonstrate in vivo fluorescence imaging of red blood cells trafficking within the capillaries of a mouse ear, at frame rates of up to 30 fps. These results can serve as a benchmark for miniature in vivo microscopy devices under development.

  2. Calibration for medium resolution off-axis electron holography using a flexible dual-lens imaging system in a JEOL ARM 200F microscope

    PubMed Central

    Cantu-Valle, J.; Ruiz-Zepeda, F.; Mendoza-Santoyo, F.; José-Yacaman, M.; Ponce, A.

    2014-01-01

    In this work the calibration of a medium resolution off-axis electron holography using a dual-lens imaging system in a JEOL ARM 200F is shown. The objective dual-lens configuration allows adjusting the field of view from 35 nm to 2.5 μm. Subsequently, the parameters used in phase shift reconstruction were calibrated considering biprism voltage versus fringe spacing (σ) and versus fringe width (W). The reliability of the transmission electron microscope performance using these parameters was achieved using gold nanoparticles of known size and adjusting the excitation voltage of the lenses. PMID:25016585

  3. Coordination of the cortisol and testosterone responses: A dual axis approach to understanding the response to social status threats.

    PubMed

    Turan, Bulent; Tackett, Jennifer L; Lechtreck, Maria T; Browning, Wesley R

    2015-12-01

    facilitate performance. These findings have implications for developing a dual axis understanding of physiological responses during social threats and competition and their function. PMID:26254769

  4. Design and implementation of a Sun tracker with a dual-axis single motor for an optical sensor-based photovoltaic system.

    PubMed

    Wang, Jing-Min; Lu, Chia-Liang

    2013-01-01

    The dual threats of energy depletion and global warming place the development of methods for harnessing renewable energy resources at the center of public interest. Solar energy is one of the most promising renewable energy resources. Sun trackers can substantially improve the electricity production of a photovoltaic (PV) system. This paper proposes a novel design of a dual-axis solar tracking PV system which utilizes the feedback control theory along with a four-quadrant light dependent resistor (LDR) sensor and simple electronic circuits to provide robust system performance. The proposed system uses a unique dual-axis AC motor and a stand-alone PV inverter to accomplish solar tracking. The control implementation is a technical innovation that is a simple and effective design. In addition, a scaled-down laboratory prototype is constructed to verify the feasibility of the scheme. The effectiveness of the Sun tracker is confirmed experimentally. To conclude, the results of this study may serve as valuable references for future solar energy applications. PMID:23467030

  5. Design and Implementation of a Sun Tracker with a Dual-Axis Single Motor for an Optical Sensor-Based Photovoltaic System

    PubMed Central

    Wang, Jing-Min; Lu, Chia-Liang

    2013-01-01

    The dual threats of energy depletion and global warming place the development of methods for harnessing renewable energy resources at the center of public interest. Solar energy is one of the most promising renewable energy resources. Sun trackers can substantially improve the electricity production of a photovoltaic (PV) system. This paper proposes a novel design of a dual-axis solar tracking PV system which utilizes the feedback control theory along with a four-quadrant light dependent resistor (LDR) sensor and simple electronic circuits to provide robust system performance. The proposed system uses a unique dual-axis AC motor and a stand-alone PV inverter to accomplish solar tracking. The control implementation is a technical innovation that is a simple and effective design. In addition, a scaled-down laboratory prototype is constructed to verify the feasibility of the scheme. The effectiveness of the Sun tracker is confirmed experimentally. To conclude, the results of this study may serve as valuable references for future solar energy applications. PMID:23467030

  6. Dual-rate-loop control based on disturbance observer of angular acceleration for a three-axis aerial inertially stabilized platform.

    PubMed

    Zhou, Xiangyang; Jia, Yuan; Zhao, Qiang; Cai, Tongtong

    2016-07-01

    This paper presents a dual-rate-loop control method based on disturbance observer (DOB) of angular acceleration for a three-axis ISP for aerial remote sensing applications, by which the control accuracy and stabilization of ISP are improved obviously. In stabilization loop of ISP, a dual-rate-loop strategy is designed through constituting inner rate loop and the outer rate loop, by which the capability of disturbance rejection is advanced. Further, a DOB-based on angular acceleration is proposed to attenuate the influences of the main disturbances on stabilization accuracy. Particularly, an information fusion method is suggested to obtain accurate angular acceleration in DOB design, which is the key for the disturbance compensation. The proposed methods are theoretically analyzed and experimentally validated to illustrate the effectiveness. PMID:27016450

  7. Thickness-controlled synthesis of vertically aligned c-axis oriented ZnO nanorod arrays: Effect of growth time via novel dual sonication sol-gel process

    NASA Astrophysics Data System (ADS)

    Firdaus Malek, Mohd; Hafiz Mamat, Mohamad; Soga, Tetsuo; Rahman, Saadah Abdul; Abu Bakar, Suriani; Syakirin Ismail, Ahmad; Mohamed, Ruziana; Alrokayan, Salman A. H.; Khan, Haseeb A.; Rusop Mahmood, Mohamad

    2016-01-01

    Zinc-oxide (ZnO) nanorod arrays were successfully prepared by using dual sonication sol-gel process. Field emission scanning electron microscopy revealed that the nanorods exhibited a hexagonal structure with a flat-end facet. The nanorods displayed similar surface morphologies and grew uniformly on the seed layer substrate, with the average diameter slightly increasing to the range of 65 to 80 nm after being immersed for varying growth times. Interestingly, thickness measurements indicated that the thicknesses of the samples increased as the growth time was extended. In addition, the X-ray diffraction spectra indicated that the prepared ZnO nanorods with a hexagonal wurtzite structure grew preferentially along the c-axis. Therefore, we can conclude that the diameter, length, and orientation of the ZnO nanorod arrays along the c-axis are controllable by adjusting the growth time, motivating us to further explore the growth mechanisms of ZnO nanorods.

  8. Micromirror-scanned dual-axis confocal microscope utilizing a gradient-index relay lens for image guidance during brain surgery

    PubMed Central

    Liu, Jonathan T.C.; Mandella, Michael J.; Loewke, Nathan O.; Haeberle, Henry; Ra, Hyejun; Piyawattanametha, Wibool; Solgaard, Olav; Kino, Gordon S.; Contag, Christopher H.

    2010-01-01

    A fluorescence confocal microscope incorporating a 1.8-mm-diam gradient-index relay lens is developed for in vivo histological guidance during resection of brain tumors. The microscope utilizes a dual-axis confocal architecture to efficiently reject out-of-focus light for high-contrast optical sectioning. A biaxial microelectromechanical system (MEMS) scanning mirror is actuated at resonance along each axis to achieve a large field of view with low-voltage waveforms. The unstable Lissajous scan, which results from actuating the orthogonal axes of the MEMS mirror at highly disparate resonance frequencies, is optimized to fully sample 500×500 pixels at two frames per second. Optically sectioned fluorescence images of brain tissues are obtained in living mice to demonstrate the utility of this microscope for image-guided resections. PMID:20459274

  9. P-23 Highlights 6/10/12: Cygnus Dual Beam Radiographic Facility Refurbishment completed at U1A tunnel in Nevada NNSS meeting Level 2 milestone

    SciTech Connect

    Deyoung, Anemarie; Smith, John R.

    2012-05-03

    A moratorium was placed on U.S. underground nuclear testing in 1992. In response, the Stockpile Stewardship Program was created to maintain readiness of the existing nuclear inventory through several efforts such as computer modeling, material analysis, and subcritical nuclear experiments (SCEs). As in the underground test era, the Nevada National Security Site (NNSS), formerly the Nevada Test Site, provides a safe and secure environment for SCEs by the nature of its isolated and secure facilities. A major tool for SCE diagnosis installed in the 05 drift laboratory is a high energy x-ray source used for time resolved imaging. This tool consists of two identical sources (Cygnus 1 and Cygnus 2) and is called the Cygnus Dual Beam Radiographic Facility (Figs. 2-6). Each Cygnus machine has 5 major elements: Marx Generator, Pulse Forming Line (PFL), Coaxial Transmission Line (CTL), 3-cell Inductive Voltage Adder (IVA), and Rod Pinch Diode. Each machine is independently triggered and may be fired in separate tests (staggered mode), or in a single test where there is submicrosecond separation between the pulses (dual mode). Cygnus must operate as a single shot machine since on each pulse the diode electrodes are destroyed. The diode is vented to atmosphere, cleaned, and new electrodes are inserted for each shot. There is normally two shots per day on each machine. Since its installation in 2003, Cygnus has participated in: 4 Subcritical Experiments (Armando, Bacchus, Barolo A, and Barolo B), a 12 shot plutonium physics series (Thermos), and 2 plutonium step wedge calibration series (2005, 2011), resulting in well over 1000 shots. Currently the Facility is in preparation for 2 SCEs scheduled for this calendar year - Castor and Pollux. Cygnus has performed well during 8 years of operations at NNSS. Many improvements in operations and performance have been implemented during this time. Throughout its service at U1a, major maintenance and replacement of many hardware items

  10. Single-shot dual-wavelength phase reconstruction in off-axis digital holography with polarization-multiplexing transmission.

    PubMed

    Wang, Zhe; Jiang, Zhuqing; Chen, Yifei

    2016-08-01

    A new system for single-shot dual-wavelength digital holographic microscopy with polarization-multiplexing path-shared transmission is presented. The key feature of the optical configuration is that the interference waves of two wavelengths having orthogonal polarization can transmit in the same interferometer paths at the same time, and two polarizers orthogonal to each other are placed in front of the CCD to realize single-shot recording of two holograms. The correlative filtering algorithm of the spatial-frequency spectrum for dual-wavelength digital holograms is reliable and efficient in the dual-wavelength path-shared configuration. The phase reconstruction in dual-wavelength digital holographic imaging is achieved by using this filtering algorithm. The experiment results of phase reconstruction of a groove grating demonstrate the reliability and validity of this optical configuration and the correlative filtering algorithm. This polarization-multiplexing configuration for dual-wavelength digital holography is compact and has more flexibility for the replacement of different-wavelength lasers. PMID:27505390

  11. Determination of the surface morphology of gold-decahedra nanoparticles using an off-axis electron holography dual-lens imaging system

    PubMed Central

    Cantu-Valle, J.; Ruiz-Zepeda, F.; Voelkl, E.; Kawasaki, M.; Santiago, U.; José-Yacaman, M.; Ponce, A.

    2014-01-01

    The purpose of this paper is to show surface irregularities in gold decahedra nanoparticles extracted by using off-axis electron holography in a JEOL ARM 200F microscope. Electron holography has been used in a dual-lens system within the objective lenses: main objective lens and objective minilens. Parameters such as biprism voltage, fringe spacing (σ), fringe width (W) and optimum fringe contrast have been calibrated. The reliability of the transmission electron microscope performance with these parameters was carried out through a plug-in in the Digital-Micrograph software, which considers the mean inner potential within the particle leading a precise determination of the morphological surface of decahedral nanoparticles obtained from the reconstructed unwrapped phase and image processing. We have also shown that electron holography has the capability to extract information from nanoparticle shape that is currently impossible to obtain with any other electron microscopy technique. PMID:24055122

  12. Nonlinear dual-axis biodynamic response of the semi-supine human body during longitudinal horizontal whole-body vibration

    NASA Astrophysics Data System (ADS)

    Huang, Ya; Griffin, Michael J.

    2008-04-01

    The resonance frequencies in frequency response functions of the human body (e.g. apparent mass and transmissibility) decrease with increasing vibration magnitude. This nonlinear biodynamic response is found with various sitting and standing postures requiring postural control. The present study measured the apparent mass of the body in a relaxed semi-supine posture with two types of longitudinal horizontal vibration (in the z-axis of the semi-supine body): (i) continuous random excitation (0.25-20 Hz) at five magnitudes (0.125, 0.25, 0.5, 0.75 and 1.0 ms -2 rms); (ii) intermittent random excitation (0.25-20 Hz) alternately at 0.25 and 1.0 ms -2 rms. With continuous random vibration, the dominant primary resonance frequency in the median normalised apparent mass decreased from 3.7 to 2.4 Hz as the vibration magnitude increased from 0.125 to 1.0 ms -2 rms. A nonlinear response was apparent in both the horizontal ( z-axis) apparent mass and the vertical ( x-axis) cross-axis apparent mass. With intermittent random vibration, as the vibration magnitude increased from 0.25 to 1.0 ms -2 rms, the median resonance frequency of the apparent mass decreased from 3.2 to 2.5 Hz whereas, with continuous random vibration over the same range of magnitudes, the resonance frequency decreased from 3.4 to 2.4 Hz. The median change in the resonance frequency (between 0.25 and 1.0 ms -2 rms) was 0.6 Hz with the intermittent random vibration and 0.9 Hz with the continuous random vibration. With intermittent vibration, the resonance frequency was higher at the high magnitude and lower at the low magnitude than with continuous vibration at the same magnitudes. The responses were consistent with passive thixotropy being a primary cause of nonlinear biodynamic responses to whole-body vibration, although reflex activity of the muscles may also have an influence.

  13. Nonlinear dual-axis biodynamic response of the semi-supine human body during vertical whole-body vibration

    NASA Astrophysics Data System (ADS)

    Huang, Ya; Griffin, Michael J.

    2008-04-01

    Nonlinear biodynamic responses are evident in many studies of the apparent masses of sitting and standing subjects in static postures that require muscle activity for postural control. In the present study, 12 male subjects adopted a relaxed semi-supine posture assumed to involve less muscle activity than during static sitting and standing. The supine subjects were exposed to two types of vertical vibration (in the x-axis of the semi-supine body): (i) continuous random vibration (0.25-20 Hz) at five magnitudes (0.125, 0.25, 0.5, 0.75, and 1.0 m s -2 rms); (ii) intermittent random vibration (0.25-20 Hz) alternately at 0.25 and 1.0 m s -2 rms. With continuous random vibration, the dominant primary resonance frequency in the median normalised apparent mass decreased from 10.35 to 7.32 Hz as the vibration magnitude increased from 0.125 to 1.0 m s -2 rms. This nonlinear response was apparent in both the vertical ( x-axis) apparent mass and in the horizontal ( z-axis) cross-axis apparent mass. As the vibration magnitude increased from 0.25 to 1.0 m s -2 rms, the median resonance frequency of the apparent mass with intermittent random vibration decreased from 9.28 to 8.06 Hz whereas, over the same range of magnitudes with continuous random vibration, the resonance frequency decreased from 9.62 to 7.81 Hz. The median change in the resonance frequency (between 0.25 and 1.0 m s -2 rms) was 1.37 Hz with the intermittent random vibration and 1.71 with the continuous random vibration. With the intermittent vibration, the resonance frequency was higher at the high magnitude and lower at the low magnitude than with continuous vibration of the same magnitudes. The response was typical of thixotropy that may be a primary cause of the nonlinear biodynamic responses to whole-body vibration.

  14. Physics design of the DARHT 2nd axis accelerator cell

    SciTech Connect

    Chen, Y J; Houck, T L; Reginato, L J; Shang, C C; Yu, S S

    1999-08-19

    The next generation of radiographic machines based on induction accelerators require very high brightness electron beams to realize the desired x-ray spot size and intensity. This high brightness must be maintained throughout the beam transport, from source to x-ray converter target. The accelerator for the second-axis of the Dual Axis Radiographic Hydrodynamic Test (DARHT) facility is being designed to accelerate a 4-kA, 2-{micro}s pulse of electrons to 20 MeV. After acceleration, the 2-{micro}s pulse will be chopped into a train of four 50-ns pulses with variable temporal spacing by rapidly deflecting the beam between a beam stop and the final transport section. The short beam pulses will be focused onto an x-ray converter target generating four radiographic pulses within the 2-{micro}s window. Beam instability due to interaction with the accelerator cells can very adversely effect the beam brightness and radiographic pulse quality. This paper describes the various issues considered in the design of the accelerator cell with emphasis on transverse impedance and minimizing beam instabilities.

  15. Evaluation of dynamic target options for dual axis radiography hydrotest facility II (DARHT II) and advanced hydrotest facility (AHF) programs

    SciTech Connect

    Krogh, M; Neurath, R; Sampayan, S; Sanders, D

    1999-03-01

    Initial results indicate that electron beams hitting targets used to generate x-rays during multipulse operation in advanced radiography facilities will generate plasma plumes which will disturb the electron beam during subsequent pulses. This, in turn, degrades the x-ray spot quality generated by the subsequent pulses. If this concern is substantiated, new facilities such as the Dual Axia Radiography Hydrotest Facility (DARHT II) and the Advanced Hydrotest Facility (AHF) will need a provision for mitigating this effect. one such provision involves moving the target with sufficient velocity that any plasmas formed are carried adequately far from the electron beam that they do not disturb it. They report the various approaches which have been considered and present data showing the maximum target rates which can be achieved with each approach.

  16. Characterization of a self-calibrating, high-precision, stacked-stage, vertical dual-axis goniometer

    NASA Astrophysics Data System (ADS)

    Mendenhall, Marcus H.; Henins, Albert; Windover, Donald; Cline, James P.

    2016-06-01

    We present details on the alignment and calibration of a goniometer assembly consisting two stacked, optically encoded, vertical axis rotation stages. A technique for its calibration is presented that utilizes a stable, uncalibrated, third stage to position a mirror in conjunction with a nulling autocollimator. Such a system provides a self-calibrating set of angular stages with absolute accuracy of  ±0.1 s of plane angle (k  =  2 expanded uncertainty) around the full circle, suitable for laboratory application. This calibration technique permits in situ, absolute angular calibration of an operational goniometer assembly that is requisite for fully traceable angle measurement, as the installation of the encoder is known to change its performance from the angular calibration data provided by the manufacturer.

  17. Characterization of a self-calibrating, high-precision, stacked-stage, vertical dual-axis goniometer

    PubMed Central

    Mendenhall, Marcus H.; Henins, Albert; Windover, Donald; Cline, James P.

    2016-01-01

    We present details on the alignment and calibration of a goniometer assembly consisting two stacked, optically encoded, vertical axis rotation stages. A technique for its calibration is presented that utilizes a stable, uncalibrated, third stage to position a mirror in conjunction with a nulling autocollimator. Such a system provides a self-calibrating set of angular stages with absolute accuracy of ±0.1 second of plane angle (k=2 expanded uncertainty) around the full circle, suitable for laboratory application. This calibration technique permits in situ, absolute angular calibration of an operational goniometer assembly that is requisite for fully traceable angle measurement, as the installation of the encoder is known to change its performance from the angular calibration data provided by the manufacturer. PMID:27330224

  18. Dual elimination of the glucagon and GLP-1 receptors in mice reveals plasticity in the incretin axis.

    PubMed

    Ali, Safina; Lamont, Benjamin J; Charron, Maureen J; Drucker, Daniel J

    2011-05-01

    Disordered glucagon secretion contributes to the symptoms of diabetes, and reduced glucagon action is known to improve glucose homeostasis. In mice, genetic deletion of the glucagon receptor (Gcgr) results in increased levels of the insulinotropic hormone glucagon-like peptide 1 (GLP-1), which may contribute to the alterations in glucose homeostasis observed in Gcgr-/- mice. Here, we assessed the contribution of GLP-1 receptor (GLP-1R) signaling to the phenotype of Gcgr-/- mice by generating Gcgr-/-Glp1r-/- mice. Although insulin sensitivity was similar in all genotypes, fasting glucose was increased in Gcgr-/-Glp1r-/- mice. Elimination of the Glp1r normalized gastric emptying and impaired intraperitoneal glucose tolerance in Gcgr-/- mice. Unexpectedly, deletion of Glp1r in Gcgr-/- mice did not alter the improved oral glucose tolerance and increased insulin secretion characteristic of that genotype. Although Gcgr-/-Glp1r-/- islets exhibited increased sensitivity to the incretin glucose-dependent insulinotropic polypeptide (GIP), mice lacking both Glp1r and the GIP receptor (Gipr) maintained preservation of the enteroinsular axis following reduction of Gcgr signaling. Moreover, Gcgr-/-Glp1r-/- islets expressed increased levels of the cholecystokinin A receptor (Cckar) and G protein-coupled receptor 119 (Gpr119) mRNA transcripts, and Gcgr-/-Glp1r-/- mice exhibited increased sensitivity to exogenous CCK and the GPR119 agonist AR231453. Our data reveal extensive functional plasticity in the enteroinsular axis via induction of compensatory mechanisms that control nutrient-dependent regulation of insulin secretion. PMID:21540554

  19. Assessing delivery and quantifying efficacy of small interfering ribonucleic acid therapeutics in the skin using a dual-axis confocal microscope

    NASA Astrophysics Data System (ADS)

    Ra, Hyejun; Gonzalez-Gonzalez, Emilio; Smith, Bryan R.; Gambhir, Sanjiv S.; Kino, Gordon S.; Solgaard, Olav; Kaspar, Roger L.; Contag, Christopher H.

    2010-05-01

    Transgenic reporter mice and advances in imaging instrumentation are enabling real-time visualization of cellular mechanisms in living subjects and accelerating the development of novel therapies. Innovative confocal microscope designs are improving their utility for microscopic imaging of fluorescent reporters in living animals. We develop dual-axis confocal (DAC) microscopes for such in vivo studies and create mouse models where fluorescent proteins are expressed in the skin for the purpose of advancing skin therapeutics and transdermal delivery tools. Three-dimensional image volumes, through the different skin compartments of the epidermis and dermis, can be acquired in several seconds with the DAC microscope in living mice, and are comparable to histologic analyses of reporter protein expression patterns in skin sections. Intravital imaging with the DAC microscope further enables visualization of green fluorescent protein (GFP) reporter gene expression in the skin over time, and quantification of transdermal delivery of small interfering RNA (siRNA) and therapeutic efficacy. Visualization of transdermal delivery of nucleic acids will play an important role in the development of innovative strategies for treating skin pathologies.

  20. DARHT Axis-I Diode Simulations II: Geometrical Scaling

    SciTech Connect

    Ekdahl, Carl A. Jr.

    2012-06-14

    Flash radiography of large hydrodynamic experiments driven by high explosives is a venerable diagnostic technique in use at many laboratories. Many of the largest hydrodynamic experiments study mockups of nuclear weapons, and are often called hydrotests for short. The dual-axis radiography for hydrodynamic testing (DARHT) facility uses two electron linear-induction accelerators (LIA) to produce the radiographic source spots for perpendicular views of a hydrotest. The first of these LIAs produces a single pulse, with a fixed {approx}60-ns pulsewidth. The second axis LIA produces as many as four pulses within 1.6-{micro}s, with variable pulsewidths and separation. There are a wide variety of hydrotest geometries, each with a unique radiographic requirement, so there is a need to adjust the radiographic dose for the best images. This can be accomplished on the second axis by simply adjusting the pulsewidths, but is more problematic on the first axis. Changing the beam energy or introducing radiation attenuation also changes the spectrum, which is undesirable. Moreover, using radiation attenuation introduces significant blur, increasing the effective spot size. The dose can also be adjusted by changing the beam kinetic energy. This is a very sensitive method, because the dose scales as the {approx}2.8 power of the energy, but it would require retuning the accelerator. This leaves manipulating the beam current as the best means for adjusting the dose, and one way to do this is to change the size of the cathode. This method has been proposed, and is being tested. This article describes simulations undertaken to develop scaling laws for use as design tools in changing the Axis-1 beam current by changing the cathode size.

  1. [Surgical treatment of a displaced femoral head fracture with a cement-free dual-headed prosthesis using a minimally invasive approach. Clinical and radiographic outcome].

    PubMed

    Wick, M; Muhr, G; Rincon, R; Lester, D

    2005-03-01

    One hundred patients treated with a cementless bipolar prosthesis for a displaced subcapital hip fracture were prospectively evaluated for clinical and radiographic outcome. All patients were operated via a minimally invasive approach; in every case we implanted a Zweymuller stem. There were 77 women and 33 men with a mean age of 80 years (29-98 years). The mean duration of the operation was 29 min (20-95 min). Full weight bearing on crutches was allowed 1 day after the operation. The mean follow-up was 2.5 years (6 months to 7 years). Two years after the operation there were 40% of the remaining 65 patients who scored between 90 and 100 on the Harris hip score, 23% between 80 and 89, 20% between 70 and 79, and 17% below 70. No patient complained about thigh pain and up to now there has been no need for femoral revision due to loosening. There was no infection or nerve lesion. In three patients there was a luxation of the prosthesis which could be reduced by closed means. Radiographs from 81 patients showed stress shielding in 97.5% mainly in Gruen zones 1 and 7. Radiolucent lines in two or more Gruen zones were found in two patients. These findings suggest that the noncemented, pressfit, grit-blasted bipolar prosthesis demonstrated similar stability and radiographic results to cemented bipolar prostheses. Stress shielding was common but did not influence longevity of the implant. We did not find any signs of protrusion. Especially in older patients with a history of cardiac disease, the noncemented bipolar prosthesis is a rational alternative to avoid intra- and postoperative complications despite the higher costs for the implant. The minimally invasive approach helps to reduce operation time and intraoperative blood loss. PMID:15778832

  2. Dual-Axis Rotational Angiography is Safe and Feasible to Detect Coronary Allograft Vasculopathy in Pediatric Heart Transplant Patients: A Single-Center Experience.

    PubMed

    Rios, Rodrigo; Loomba, Rohit S; Foerster, Susan R; Pelech, Andrew N; Gudausky, Todd M

    2016-04-01

    Coronary allograft vasculopathy (CAV) is the leading cause of graft failure in pediatric heart transplant recipients, also adding to mortality in this patient population. Coronary angiography is routinely performed to screen for CAV, with conventional single-plane or bi-plane angiography being utilized. Dual-axis rotational coronary angiography (RA) has been described, mostly in the adult population, and may offer reduction in radiation dose and contrast volume. Experience with this in the pediatric population is limited. This study describes a single-institution experience with RA for screening for CAV in pediatric patients. The catheterization database at our institution was used to identify pediatric heart transplant recipients having undergone RA to screen for CAV. Procedural data including radiation dose, fluoroscopy time, contrast volume, and procedure time were collected for each catheterization. The number of instances in which RA was not successful, ECG changes were present, and CAV was detected were also collected for each catheterization. A total of 97 patients underwent 345 catheterizations utilizing RA. Median radiation dose-area product per kilogram was found to be 341.7 (mGy cm(2)/kg), total air kerma was 126.8 (mGy), procedure time was 69 min, fluoroscopy time was 9.9 min, and contrast volume was 13 ml. A total of 17 (2 %) coronary artery injections out of 690 could not be successfully imaged using RA. A total of 14 patients had CAV noted at any point, 10 of whom had progressive CAV. Electrocardiographic changes were documented in a total of 10 (3 %) RA catheterizations. Procedural characteristics did not differ between serial catheterizations. RA is safe and feasible for CAV screening in pediatric heart transplant recipients while offering coronary imaging in multiple planes compared to conventional angiography. PMID:26846123

  3. Dual-axis beam correction for an array of single-mode diode laser emitters using a laser-written custom phase-plate.

    PubMed

    Trela, Natalia; Baker, Howard J; Wendland, Jozef J; Hall, Denis R

    2009-12-21

    A single optical component for a diode laser bar combines fast-axis smile and lens error correction with slow-axis collimation. Produced by laser-machining/polishing, it provides 0.9 mm focal length, 200 microm pitch slow-axis collimation on the same surface that corrects fast-axis errors. Custom fabrication enables fill-factor optimization for the 49 single-mode beams and gives parallel collimation with rms pointing errors of 3% and 6% of the far-field divergence for the fast- and slow-axis array respectively. Sub-micron pitch mismatch between the slow-axis lens and emitter arrays, and beam pointing changes by thermal expansion of the laser bar are detected. PMID:20052066

  4. Off-axis electron holography with a dual-lens imaging system and its usefulness in 2-D potential mapping of semiconductor devices.

    PubMed

    Wang, Y Y; Kawasaki, M; Bruley, J; Gribelyuk, M; Domenicucci, A; Gaudiello, J

    2004-11-01

    A variable magnification electron holography, applicable for two-dimensional (2-D) potential mapping of semiconductor devices, employing a dual-lens imaging system is described. Imaging operation consists of a virtual image formed by the objective lens (OL) and a real image formed in a fixed imaging plane by the objective minilens. Wide variations in field of view (100-900 nm) and fringe spacing (0.7-6 nm) were obtained using a fixed biprism voltage by varying the total magnification of the dual OL system. The dual-lens system allows fringe width and spacing relative to the object to be varied roughly independently from the fringe contrast, resulting in enhanced resolution and sensitivity. The achievable fringe width and spacing cover the targets needed for devices in the semiconductor technology road map from the 350 to 45 nm node. Two-D potential maps for CMOS devices with 220 and 70 nm gate lengths were obtained. PMID:15450653

  5. Radiographic scale grid for supervoltage radiographs.

    PubMed

    Wong, J T

    1975-01-01

    This paper deals with the construction and practical application of a radiographic scale grid incorporated into high energy radiation therapy machines in making port radiographs. The gadet is designed especially for the numerous small radiation therapy departments in community hospitals and private practices that do not have the sophistication provided by a simulator. PMID:812144

  6. Installation for producing radiographic layer images

    SciTech Connect

    Kinanen, I.

    1984-11-06

    The purpose of the invention is to create a mechanically uncomplicated installation for producing radiographic layer images, making it possible to use small radiation dosages and, however, to collect sufficiently information on the object by one exposure, whereby separation of the superimposed layers from each other in a desired way for visualization can be accomplished by means of tomosynthesis. The installation includes radiation generating means collimating means for confining the radiation and focusing it on an object to be radiographed, e.g. a patient, means for detecting the radiation passed through the object and means for storing and processing the information contained in said detection. Said collimating means comprise a collimation unit including at least two separate, narrow, contiguous, substantially parallel collimating slots for producing narrow, fan-shaped beams, said slots being arranged preferably in alignment with the longitudinal axis of the object to be radiographed. The installation also includes means for displacing said collimating slots and the object to be radiographed in relation to each other at least substantially in alignment with the normal of said collimating slots, those parts of the object selected to be radiographed being arranged to be exposed to radiation by said narrow fan-shaped beams from a number of different directions. The information obtained from the object to be radiographed is stored preferably in digital form and processed for visualization.

  7. Visual simulation of radiographs

    SciTech Connect

    Laguna, G.

    1985-01-18

    A method for computer simulation of radiographs has been added to the LLNL version of the solid modeler TIPS-1 (Technical Information Processing System-1). This new tool will enable an engineer to compare an actual radiograph of a solid to its computer-generated counterpart. The appearance of discrepancies between the two can be an indication of flaws in the solid object. Simulated radiographs can also be used to preview the placement of x-ray sources to focus on areas of concern before actual radiographs are made.

  8. RETOUCHING OF RADIOGRAPHS.

    PubMed

    IRVINE, R F

    1964-06-13

    Underexposed or underdeveloped radiographs which could have been used for teaching or publication were treated prior to photographing with a technique similar to that used for photographic negative retouching. This method enables these radiographs to be used for diagnostic demonstration, where before they would have been condemned as unsuitable for reproduction. The method is simple and requires very little experience or equipment. PMID:14156836

  9. Are dental radiographs safe?

    PubMed

    Abbott, P

    2000-09-01

    Dental patients are often aware that radiation has the potential to harm them but they do not usually understand how or why and what potential harmful effects may arise from dental radiographs. The potential for undesirable effects must be balanced against the benefits obtained from radiographs. Dentists should address the concerns of patients who question the need for radiographs and allow them to make an informed decision. Data are available that relate radiation exposure levels from medical and dental radiographs to normal background exposure levels and allow comparisons with everyday risks in life. Recognized radiation authorities publish guidelines to help dentists with their use of radiographs, although, due to the time lag associated with testing and the publication of results, some of the published data may not always be entirely relevant to currently used X-ray machines and techniques. Dentists also have professional obligations not only to limit the use of radiographs to potentially beneficial situations but also to take good quality diagnostic radiographs, to limit the doses used, to use good radiation safety measures and to use modern equipment to achieve the best possible films. Radiographs must then be properly developed and viewed under appropriate conditions to gain the maximum possible diagnostic information from each exposure. PMID:11062940

  10. Tuning the DARHT Axis-II linear induction accelerator focusing

    SciTech Connect

    Ekdahl, Carl A.

    2012-04-24

    Flash radiography of large hydrodynamic experiments driven by high explosives is a well-known diagnostic technique in use at many laboratories, and the Dual-Axis Radiography for Hydrodynamic Testing (DARHT) facility at Los Alamos produces flash radiographs of large hydrodynamic experiments. Two linear induction accelerators (LIAs) make the bremsstrahlung radiographic source spots for orthogonal views of each test. The 2-kA, 20-MeV Axis-I LIA creates a single 60-ns radiography pulse. The 1.7-kA, 16.5-MeV Axis-II LIA creates up to four radiography pulses by kicking them out of a longer pulse that has a 1.6-{mu}s flattop. The Axis-II injector, LIA, kicker, and downstream transport (DST) to the bremsstrahlung converter are described. Adjusting the magnetic focusing and steering elements to optimize the electron-beam transport through an LIA is often called 'tuning.' As in all high-current LIAs, the focusing field is designed to be as close to that of the ideal continuous solenoid as physically possible. In ideal continuous solenoidal transport a smoothly varying beam size can easily be found for which radial forces balance, and the beam is said to be 'matched' to the focusing field. A 'mismatched' beam exhibits unwanted oscillations in size, which are a source of free energy that contributes to emittance growth. This is undesirable, because in the absence of beam-target effects, the radiographic spot size is proportional to the emittance. Tuning the Axis-II LIA is done in two steps. First, the solenoidal focusing elements are set to values designed to provide a matched beam with little or no envelope oscillations, and little or no beam-breakup (BBU) instability growth. Then, steering elements are adjusted to minimize the motion of the centroid of a well-centered beam at the LIA exit. This article only describes the design of the tune for the focusing solenoids. The DARHT Axis-II LIA was required to be re-tuned after installing an accelerator cell to replace a failed

  11. The metabolic, stress axis, and hematology response of zilpaterol hydrochloride supplemented beef heifers when exposed to a dual corticotropin-releasing hormone and vasopressin challenge.

    PubMed

    Buntyn, J O; Burdick Sanchez, N C; Schmidt, T B; Erickson, G E; Sieren, S E; Jones, S J; Carroll, J A

    2016-07-01

    The objective of this study was to determine the metabolic, stress, and hematology response of beef heifers supplemented with zilpaterol hydrochloride (ZH) when exposed to an endocrine stress challenge. Heifers ( = 20; 556 ± 7 kg BW) were randomized into 2 treatment groups: 1) control (CON), no ZH supplementation, and 2) zilpaterol (ZIL), supplemented with ZH at 8.33 mg/kg (DM basis). The ZIL group was supplemented ZH for 20 d, with a 3-d withdrawal period. On d 24, heifers received an intravenous bolus of corticotropin-releasing hormone (CRH; 0.3 µg/kg BW) and arginine vasopressin (VP; 1.0 µg/kg BW) to activate the stress axis. Blood samples were collected at 30-min intervals for serum and 60-min intervals for plasma and whole blood, from -2 to 8 h relative to the challenge at 0 h (1000 h). Samples were analyzed for glucose, insulin, NEFA, blood urea nitrogen (BUN), cortisol, epinephrine, norepinephrine, and complete blood cell counts. Following the challenge, cattle were harvested over a 3-d period. Liver, LM, and biceps femoris (BF) samples were collected and analyzed for glucose, lactate, and glycolytic potential (GP). There was a treatment ( ≤ 0.001) effect for vaginal temperature (VT), with ZIL having a 0.1°C decrease in VT when compared with CON. A treatment × time effect ( = 0.002) was observed for NEFA. A treatment effect was observed for BUN; ZIL had decreased BUN concentrations compared with CON ( < 0.001) prior to the challenge; however, no treatment × time effect was observed. There was also a treatment effect for cortisol ( ≤ 0.01) and epinephrine ( = 0.003); ZIL had decreased cortisol and epinephrine during the CRH/VP challenge when compared with CON. There was a time effect for total white blood cells, lymphocytes, and monocytes; each variable increased ( ≤ 0.01) 2 h postchallenge. Additionally, neutrophil counts decreased ( ≤ 0.01) in response to CRH/VP challenge in both treatment groups. Glucose concentrations within the LM were

  12. RF generation in the DARHT Axis-II beam dump

    SciTech Connect

    Ekdahl, Carl A. Jr.

    2012-05-03

    We have occasionally observed radio-frequency (RF) electromagnetic signals in the downstream transport (DST) of the second axis linear induction accelerator (LIA) at the dual-axis radiographic hydrodynamic testing (DARHT) facility. We have identified and eliminated some of the sources by eliminating the offending cavities. However, we still observe strong RF in the range 1 GHz t0 2 GHz occurring late in the {approx}2-{micro}s pulse that can be excited or prevented by varying the downstream tune. The narrow frequency width (<0.5%) and near exponential growth at the dominant frequency is indicative of a beam-cavity interaction, and electro-magnetic simulations of cavity structure show a spectrum rich in resonances in the observed frequency range. However, the source of beam produced RF in the cavity resonance frequency range has not been identified, and it has been the subject of much speculation, ranging from beam-plasma or beam-ion instabilities to unstable cavity coupling.

  13. Beam breakup calculations for the second axis of DARHT

    SciTech Connect

    Fawley, William M.; Chen, Y.-J.; Houck, T.L.

    1999-08-20

    The accelerator for the second axis of the Dual Axis Radiographic Hydrodynamic Test (DARHT) facility will produce a 4-kA, 20-MeV, 2-{micro}s output electron beam with a design goal of less than 1000 {pi} mm-mrad normalized transverse emittance and less than 0.5-mm beam centroid motion. In order to meet this goal, the beam transport must have excellent optics and the beam breakup instability (BBU) must be limited in growth. Using a number of simulation codes such as AMOS and BREAKUP, we have modeled the transverse impedances of the DARHT-II accelerator cells and the electron beam response to different transverse excitations such as injector RF noise, magnetic dipole fields arising from the 90-degree bend between the cathode stalk and insulator column, and downstream solenoid alignment errors. The very low Q ({approx}2) predicted for the most important TM dipole modes has prompted us to extend the BREAKUP code to be able to use the dipole wakefields calculated by AMOS in addition to the most usual discrete frequency BBU mode model. We present results for the predicted BBU growth and the empirical sensitivity to various machine parameters.

  14. Radiographic Assessment for Back Pain

    MedlinePlus

    Radiographic Assessment for Back Pain What are Radiographic Assessments? When Should I get an X-ray for Low Back Pain? Other Reasons for Having an X-ray What ... What are Radiographic Assessments? Radiographic assessments for low back pain involve the use of X-rays to determine ...

  15. The mechanical design for the second axis beam transport line for the DARHT facility

    SciTech Connect

    Bertolini, L R; Alford, O J; Paul, A C; Shang, C C; Westenkow, G A

    1999-03-23

    This paper describes the mechanical design of the downstream beam transport line for the second axis of the Dual Axis Radiographic Hydrodynamic Test (DARHT II) facility. The DARHT II project is a collaboration between LANL, LBNL, and LLNL. DARHT II is a 20-MeV, 2000-Amperes, 2-µsec pulse length linear induction accelerator designed to generate short bursts of x-rays for the purpose of radiographing dense objects. The downstream beam transport line is an 18-meter long region extending from the end of the accelerator to the bremsstrahlung target. Within this proposed transport line there are 17 conventional solenoid, quadrupole and dipole magnets; as well as several specialty magnets, which transport and focus the beam to the target and beam dumps. There is a high power beam dump, which is designed to absorb the 80-kJ of beam energy during accelerator start-up and operation. The beamline vacuum chamber has an 8-cm diameter aperture and operates at an average pressure of 10-7 Torr.

  16. Weld radiograph enigmas

    NASA Technical Reports Server (NTRS)

    Jemian, Wartan A.

    1986-01-01

    Weld radiograph enigmas are features observed on X-ray radiographs of welds. Some of these features resemble indications of weld defects, although their origin is different. Since they are not understood, they are a source of concern. There is a need to identify their causes and especially to measure their effect on weld mechanical properties. A method is proposed whereby the enigmas can be evaluated and rated, in relation to the full spectrum of weld radiograph indications. Thie method involves a signature and a magnitude that can be used as a quantitive parameter. The signature is generated as the diference between the microdensitometer trace across the radiograph and the computed film intensity derived from a thickness scan along the corresponding region of the sample. The magnitude is the measured difference in intensity between the peak and base line values of the signature. The procedure is demonstated by comparing traces across radiographs of a weld sample before and after the introduction of a hole and by a system based on a MacIntosh mouse used for surface profiling.

  17. Diode magnetic-field influence on radiographic spot size

    SciTech Connect

    Ekdahl, Carl A. Jr.

    2012-09-04

    Flash radiography of hydrodynamic experiments driven by high explosives is a well-known diagnostic technique in use at many laboratories. The Dual-Axis Radiography for Hydrodynamic Testing (DARHT) facility at Los Alamos was developed for flash radiography of large hydrodynamic experiments. Two linear induction accelerators (LIAs) produce the bremsstrahlung radiographic source spots for orthogonal views of each experiment ('hydrotest'). The 2-kA, 20-MeV Axis-I LIA creates a single 60-ns radiography pulse. For time resolution of the hydrotest dynamics, the 1.7-kA, 16.5-MeV Axis-II LIA creates up to four radiography pulses by slicing them out of a longer pulse that has a 1.6-{micro}s flattop. Both axes now routinely produce radiographic source spot sizes having full-width at half-maximum (FWHM) less than 1 mm. To further improve on the radiographic resolution, one must consider the major factors influencing the spot size: (1) Beam convergence at the final focus; (2) Beam emittance; (3) Beam canonical angular momentum; (4) Beam-motion blur; and (5) Beam-target interactions. Beam emittance growth and motion in the accelerators have been addressed by careful tuning. Defocusing by beam-target interactions has been minimized through tuning of the final focus solenoid for optimum convergence and other means. Finally, the beam canonical angular momentum is minimized by using a 'shielded source' of electrons. An ideal shielded source creates the beam in a region where the axial magnetic field is zero, thus the canonical momentum zero, since the beam is born with no mechanical angular momentum. It then follows from Busch's conservation theorem that the canonical angular momentum is minimized at the target, at least in principal. In the DARHT accelerators, the axial magnetic field at the cathode is minmized by using a 'bucking coil' solenoid with reverse polarity to cancel out whatever solenoidal beam transport field exists there. This is imperfect in practice, because of

  18. Advanced radiographic imaging techniques.

    NASA Technical Reports Server (NTRS)

    Beal, J. B.; Brown, R. L.

    1973-01-01

    Examination of the nature and operational constraints of conventional X-radiographic and neutron imaging methods, providing a foundation for a discussion of advanced radiographic imaging systems. Two types of solid-state image amplifiers designed to image X rays are described. Operational theory, panel construction, and performance characteristics are discussed. A closed-circuit television system for imaging neutrons is then described and the system design, operational theory, and performance characteristics are outlined. Emphasis is placed on a description of the advantages of these imaging systems over conventional methods.

  19. Radiographic intensifying screen

    SciTech Connect

    Ochiai, T.

    1985-02-26

    A radiographic intensifying screen comprising a substrate and a fluorescent layer provided thereon and consisting essentially of a binder and a radioluminescent phosphor dispersed therein. The binder comprises linear polyester resin or linear polyester resin crosslinked with a crosslinking agent. The screen exhibits improved physical properties.

  20. Neutron radiographic viewing system

    NASA Technical Reports Server (NTRS)

    Leysath, W.; Brown, R. L.

    1972-01-01

    Neutron radiographic viewing system consisting of camera head and control processor is developed for use in nondestructive testing applications. Camera head consists of neutron-sensitive image intensifier system, power supply, and SEC vidicon camera head. Both systems, with their optics, are housed on test mount.

  1. Approach to Pediatric Chest Radiograph.

    PubMed

    Jana, Manisha; Bhalla, Ashu Seith; Gupta, Arun Kumar

    2016-06-01

    Chest radiograph remains the first line imaging modality even today, especially in ICU settings. Hence proper interpretation of chest radiographs is crucial, which can be achieved by adopting a systematic approach and proper description and identification of abnormalities. In this review, the authors describe a short and comprehensive way of interpreting the pediatric chest radiograph. PMID:26983619

  2. ELECTRO-OPTIC BEAM POSITION AND PULSED POWER MONITORS FOR THE SECOND AXIS OF DARHT.

    SciTech Connect

    M. BRUBAKER; C. EKDAHL; C. YAKYMYSHYN

    2001-05-01

    The second axis of the Dual Axis Radiographic Hydro-Test (DARHT) facility utilizes a long pulse electron beam having a duration in excess of two microseconds. This time scale poses problems for many conventional diagnostics that rely upon electrical cables to transmit signals between the accelerator and recording equipment. Recognizing that transit time isolation is not readily achieved for the long pulse regime, difficulties resulting from ground loops are anticipated. An electro-optic (EO) voltage sensor technology has been developed to address this issue. The EO sensor exploits the Pockels effect in Bi{sub 4}Ge{sub 3}O{sub 12} (BGO) to provide linear modulation of laser light in response to the voltage induced on a pickup electrode. Fiber coupling between the light source, Pockels cell and receiver ensures complete galvanic isolation with improved cost and performance as compared to conventional sensors fitted with fiber optic links. Furthermore, the EO approach requires that only the passive sensor element be located near the accelerator while the light source and receiver can be installed in remote locations. This paper describes the design and development of EO sensors for electron beam and pulsed power monitoring on the second axis of DARHT. Typical calibration and testing data for the sensors is also presented.

  3. Large Format Radiographic Imaging

    SciTech Connect

    J. S. Rohrer; Lacey Stewart; M. D. Wilke; N. S. King; S. A Baker; Wilfred Lewis

    1999-08-01

    Radiographic imaging continues to be a key diagnostic in many areas at Los Alamos National Laboratory (LANL). Radiographic recording systems have taken on many form, from high repetition-rate, gated systems to film recording and storage phosphors. Some systems are designed for synchronization to an accelerator while others may be single shot or may record a frame sequence in a dynamic radiography experiment. While film recording remains a reliable standby in the radiographic community, there is growing interest in investigating electronic recording for many applications. The advantages of real time access to remote data acquisition are highly attractive. Cooled CCD camera systems are capable of providing greater sensitivity with improved signal-to-noise ratio. This paper begins with a review of performance characteristics of the Bechtel Nevada large format imaging system, a gated system capable of viewing scintillators up to 300 mm in diameter. We then examine configuration alternatives in lens coupled and fiber optically coupled electro-optical recording systems. Areas of investigation include tradeoffs between fiber optic and lens coupling, methods of image magnification, and spectral matching from scintillator to CCD camera. Key performance features discussed include field of view, resolution, sensitivity, dynamic range, and system noise characteristics.

  4. Colonic interposition: radiographic evaluation.

    PubMed

    Agha, F P; Orringer, M B

    1984-04-01

    This report reviews the clinical and radiographic features of 40 patients who underwent visceral esophageal substitution with colon for benign or malignant lesions of the esophagus. The incidence and radiographic identification of complications are discussed. All patients were routinely examined with barium esophagrams on postoperative day 10. If an anastomotic leak was suspected clinically before this time, studies were performed using water-soluble iodinated contrast material. Follow-up barium esophagrams were obtained 1-96 months after operation (average, 60 months) in 24 patients. Eight patients (21%) demonstrated asymptomatic "jejunization" of the colonic mucosa with no attributable clinical manifestations; this finding resolved in 1-3 months, without sequelae, and has not been reported before. The spectrum of ischemic changes in the colonic segment included mucosal edema, spasm, ulceration, loss of haustration, and frank necrosis. Radiographically detectable early postoperative complications included anastomotic leak in six (three pharyngocolic, three cervical esophagocolic) and aspiration of barium into the tracheobronchial tree due to incoordinated swallowing in eight. Late postoperative complications included anastomotic narrowing (12) malfunctioning of the colon due to impaired emptying (five), recurrent aspiration pneumonia (three), small bowel obstruction (three), transhiatal herniation of small bowel through the diaphragmatic hiatus (one), and reflux into the retained bypassed esophagus (one). PMID:6608225

  5. Radiographic quality control devices.

    PubMed

    2000-04-01

    In this study, we evaluate eight radiographic quality control (QC) devices, which noninvasively measure the output from a variety of diagnostic x-ray production systems. When used as part of a quality assurance (QA) program, radiographic QC devices help ensure that x-ray equipment is working within acceptable limits. This in turn helps ensure that high-quality images are achieved with appropriate radiation doses and that resources are used efficiently (for example, by minimizing the number of repeat exposures required). Our testing focused on the physical performance, ease of use, and service and maintenance characteristics that affect the use of these devices for periodic, routine measurements of x-ray system parameters. We found that all the evaluated models satisfactorily measure all the parameters normally needed for a QA program. However, we did identify a number of differences among the models--particularly in the range of exposure levels that can be effectively measured and the ease of use. Three models perform well for a variety of applications and are very easy to use; we rate them Preferred. Three additional models have minor limitations but otherwise perform well; we rate them Acceptable. We recommend against purchasing two models because, although each performs acceptably for most applications, neither model can measure low levels of radiation. This Evaluation covers devices designed to measure the output of x-ray tubes noninvasively. These devices, called radiographic quality control (QC) devices, or QC meters, are typically used by medical physicists, x-ray engineers, biomedical engineers, and suitably trained radiographic technologists to make QC measurements. We focus on the use of these devices as part of an overall quality assurance (QA) program. We have not evaluated their use for other applications, such as acceptance testing. To be included in this study, a device must be able to measure the exposure- and kVp-related characteristics of most x

  6. Radiographic solution contamination.

    PubMed

    Hardman, P K; Tilmon, M F; Taylor, T S

    1987-06-01

    Contamination of processor solutions adversely affects the image quality of radiographic films. The purpose of this study was to determine the amount of developer or fixer contaminant that was necessary to produce a significant densitometric change in the base plus fog, speed, or contrast optical density readings for panoramic film. Significant differences in base plus fog (after 16 mL of fixer contaminant was added to developer), speed index (after 4 mL), and contrast index (after 8 mL) were observed in comparison with control values. PMID:3473399

  7. Contamination of dental radiographic solutions.

    PubMed

    Tamburus, J R; Pardini, L C; Watanabe, P C

    1995-01-01

    Thirteen groups of periapical radiographic films were evaluated to determine and compare within and between groups the effects of contamination of the fixer solution with developing solution during radiographic processing. An aluminum penetrometer was used as the radiographic object to produce different optical densities. The images were compared using radiographic density and contrast as parameters. There were significant differences between the control groups and the groups processed with a contaminated fixer solution. No statistically significant differences were observed in the intragroup comparisons. PMID:8688649

  8. Computer enhancement of radiographs

    NASA Technical Reports Server (NTRS)

    Dekaney, A.; Keane, J.; Desautels, J.

    1973-01-01

    Examination of three relevant noise processes and the image degradation associated with Marshall Space Flight Center's (MSFC) X-ray/scanning system was conducted for application to computer enhancement of radiographs using MSFC's digital filtering techniques. Graininess of type M, R single coat and R double coat X-ray films was quantified as a function of density level using root-mean-square (RMS) granularity. Quantum mottle (including film grain) was quantified as a function of the above film types, exposure level, specimen material and thickness, and film density using RMS granularity and power spectral density (PSD). For various neutral-density levels the scanning device used in digital conversion of radiographs was examined for noise characteristics which were quantified by RMS granularity and PSD. Image degradation of the entire pre-enhancement system (MG-150 X-ray device; film; and optronics scanner) was measured using edge targets to generate modulation transfer functions (MTF). The four parameters were examined as a function of scanning aperture sizes of approximately 12.5 25 and 50 microns.

  9. 10 CFR 34.46 - Supervision of radiographers' assistants.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Radiation Safety Requirements § 34.46 Supervision of radiographers' assistants. Whenever a radiographer's assistant uses radiographic exposure devices,...

  10. 10 CFR 34.46 - Supervision of radiographers' assistants.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Radiation Safety Requirements § 34.46 Supervision of radiographers' assistants. Whenever a radiographer's assistant uses radiographic exposure devices,...

  11. 10 CFR 34.46 - Supervision of radiographers' assistants.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Radiation Safety Requirements § 34.46 Supervision of radiographers' assistants. Whenever a radiographer's assistant uses radiographic exposure devices,...

  12. [Panoramic radiographs in dental diagnostics].

    PubMed

    van der Stelt, P F

    2016-04-01

    Panoramic radiographs are frequently used in dental practice in addition to bitewing radiographs and periapical radiographs. The way a panoramic photograph is created is different from that of a projection image, such as bitewing and periapical radiographs. As a result, the sharpness of detail is much less, and overlap of structures occurs in different areas of the image. Consequently the diagnostic utility is limited to the recognition of anomalies for which small details play a lesser role. The advantage of a panoramic radiograph is that structures over a large area are shown in their relative location. Because of the lower resolution and the higher dose of radiation to the patient compared with a series of intraoral images, the panoramic radiograph is not indicated during a periodic check-up. If clinical inspection indicates a need for it and as a supplement to an intraoral radiograph, a panoramic radiograph can, however, be appropriate in cases of abnormalities that extend over a larger area, such as tumours and developmental disorders. PMID:27073808

  13. Proposed inductive voltage adder based accelerator concepts for the second axis of DARHT

    SciTech Connect

    Smith, D.L.; Johnson, D.L.; Boyes, J.D.

    1997-06-01

    As participants in the Technology Options Study for the second axis of the Dual Axis Radiographic HydroTest (DARHT) facility located at Los Alamos National Laboratories, the authors have considered several accelerator concepts based on the Inductive Voltage Adder (IVA) technology that is being used successfully at Sandia on the SABRE and HERMES-III facilities. The challenging accelerator design requirements for the IVA approach include: {ge}12-MeV beam energy; {approximately}60-ns electrical pulse width; {le}40-kA electron beam current; {approximately}1-mm diameter e-beam; four pulses on the same axis or as close as possible to that axis; and an architecture that fits within the existing building envelope. To satisfy these requirements the IVA concepts take a modular approach. The basic idea is built upon a conservative design for eight ferromagnetically isolated 2-MV cavities that are driven by two 3 to 4-{Omega} water dielectric pulse forming lines (PFLs) synchronized with laser triggered gas switches. The 100-{Omega} vacuum magnetically insulated transmission line (MITL) would taper to a needle cathode that produces the electron beam(s). After considering many concepts the authors narrowed their study to the following options: (A) Four independent single pulse drivers powering four single pulse diodes; (B) Four series adders with interleaved cavities feeding a common MITL and diode; (C) Four stages of series PFLs, isolated from each other by triggered spark gap switches, with single-point feeds to a common adder, MITL, and diode; and (D) Isolated PFLs with multiple-feeds to a common adder using spark gap switches in combination with saturable magnetic cores to isolate the non-energized lines. The authors will discuss these options in greater detail identifying the challenges and risks associated with each.

  14. BBU and Corkscrew Growth Predictions for the DARHT Second Axis Accelerator

    SciTech Connect

    Chen, Y J; Fawley, W M

    2001-06-12

    The second axis accelerator of the Dual Axis Radiographic Hydrodynamic Test (DARHT-II) facility will produce a 2-kA, 20-MeV, 2-{micro}s output electron beam with a design goal of less than 1000 {pi} mm-mrad normalized transverse emittance. In order to meet this goal, both the beam breakup instability (BBU) and transverse ''corkscrew'' motion (due to chromatic phase advance) must be limited in growth. Using data from recent experimental measurements of the transverse impedance of actual DARHT-II accelerator cells by Briggs et al., they have used the LLNL BREAKUP code to predict BBU and corkscrew growth in DARHT-II. The results suggest that BBU growth should not seriously degrade the final achievable spot size at the x-ray converter, presuming the initial excitation level is of the order 100 microns or smaller. For control of corkscrew growth, a major concern is the number of ''tuning'' shots needed to utilize effectively the ''tuning-V'' algorithm. Presuming that the solenoid magnet alignment falls within spec, they believe that possibly as few as 50-100 shots will be necessary to set the dipole corrector magnet currents. They give some specific examples of tune determination for a hypothetical set of alignment errors.

  15. BBU and Corkscrew Growth Predictions for the Darht Second Axis Accelerator

    SciTech Connect

    Chen, Y.J.; Fawley, W.M.

    2001-06-12

    The second axis accelerator of the Dual Axis Radiographic Hydrodynamic Test (DARHT-II) facility will produce a 2-kA, 20-MeV, 2-{micro}s output electron beam with a design goal of less than 1000 {pi} mm-mrad normalized transverse emittance. In order to meet this goal, both the beam breakup instability (BBJ) and transverse corkscrew motion (due to chromatic phase advance) must be limited in growth. Using data from recent experimental measurements of the transverse impedance of actual DARHT-II accelerator cells by Briggs et al. [2], they have used the LLNL BREAKUP code to predict BBU and corkscrew growth in DARHT-II. The results suggest that BBU growth should not seriously degrade the final achievable spot size at the x-ray converter, presuming the initial excitation level is of the order 100 microns or smaller. For control of corkscrew growth, a major concern is the number of tuning shots needed to utilize effectively the tuning-V algorithm [3]. Presuming that the solenoid magnet alignment falls within spec, they believe that possibly as few as 50-100 shots will be necessary to set the dipole corrector magnet currents. They give some specific examples of tune determination for a hypothetical set of alignment errors.

  16. Reliability and Lifetime Testing of the DARHT Second AxisInduction Cells

    SciTech Connect

    Waldron, W.L.; Nielsen, K.E.; Spence, P.W.

    2005-06-30

    The Dual-Axis Radiographic Hydrodynamics Test (DARHT) facility will employ two perpendicular electron linear induction accelerators to produce intense, bremsstrahlung x-ray pulses for flash radiography. The second axis, DARHT II, features a 3 MeV injector and a 15 MeV, 2 kA, 1.5 {micro}s accelerator consisting of 74 induction cells and drivers. High reliability and lifetime of the induction cells are major requirements because of the cost of execution of hydro tests and because the time and effort to remove and refurbish a failed cell is considerable. Research and development efforts have identified problems in the original cell design and means to upgrade the design, performance, and reliability of the linear induction cells. Physical changes in the cell oil region, the cell vacuum region, and the cell drivers, together with different operational and maintenance procedures, have been implemented in six prototype units. This paper addresses the acceptance criteria and acceptance tests applied to the prototype accelerator cells. These tests validate the upgraded cell design and demonstrate that it meets the essential electrical and reliability requirements prior to committing to refurbishment of the full ensemble of DARHT II cells. The prototype acceptance test results are presented and discussed in terms of the confidence level in which the required cell lifetime and reliability are met by the upgraded design and modified operation and maintenance procedures.

  17. Radiographic X-Ray Pulse Jitter

    SciTech Connect

    Mitton, C. V., Good, D. E., Henderson, D. J., Hogge, K. W.

    2011-01-15

    The Dual Beam Radiographic Facility consists of two identical radiographic sources. Major components of the machines are: Marx generator, water-filled pulse-forming line (PFL), water-filled coaxial transmission line, three-cell inductive voltage adder, and rod-pinch diode. The diode pulse has the following electrical specifications: 2.25-MV, 60-kA, 60-ns. Each source has the following x-ray parameters: 1-mm-diameter spot size, 4-rad at 1 m, 50-ns full width half max. The x-ray pulse is measured with PIN diode detectors. The sources were developed to produce high resolution images on single-shot, high-value experiments. For this application it is desirable to maintain a high level of reproducibility in source output. X-ray pulse jitter is a key metric for analysis of reproducibility. We will give measurements of x-ray jitter for each machine. It is expected that x-ray pulse jitter is predominantly due to PFL switch jitter, and therefore a correlation of the two will be discussed.

  18. Sensitometric responses of selected medical radiographic films.

    PubMed

    Kofler, J M; Gray, J E

    1991-12-01

    Radiographic films produce different densities and contrast when processor changes occur, and the magnitude and rate of change vary with film type. The ability to detect and interpret the clinical importance of film density changes may depend on the method of sensitometry used. The characteristics of several medical radiographic films and various sensitometers were examined under three sensitometric variations and five processing variations. Of all variations used, only exposure with a single-versus a double-sided sensitometer caused a film type to have a marked different response. The results indicate that mismatching the sensitometer spectral output with the spectral sensitivity of the film in most cases does not affect the density changes of the film. The fact that a few films may be sensitive to differences in spectral content of the exposing light and dual- versus single-sided exposure and that only a limited number of film types were tested, however, leads to the prudent conclusion that the exposure conditions for quality control purposes should match clinical exposure conditions as closely as possible. PMID:1947114

  19. Abdominal Dual Energy Imaging

    NASA Astrophysics Data System (ADS)

    Sommer, F. Graham; Brody, William R.; Cassel, Douglas M.; Macovski, Albert

    1981-11-01

    Dual energy scanned projection radiography of the abdomen has been performed using an experimental line-scanned radiographic system. Digital images simultaneously obtained at 85 and 135 kVp are combined, using photoelectric/Compton decomposition algorithms to create images from which selected materials are cancelled. Soft tissue cancellation images have proved most useful in various abdominal imaging applications, largely due to the elimination of obscuring high-contrast bowel gas shadows. These techniques have been successfully applied to intravenous pyelography, oral cholecystography, intravenous abdominal arteriog-raphy and the imaging of renal calculi.

  20. Radiographic imaging and possible causes of a carpal varus deformity in an Asian elephant (Elephas maximus).

    PubMed

    Kaulfers, Carola; Geburek, Florian; Feige, Karsten; Knieriem, Andreas

    2010-12-01

    The carpal region of an Asian elephant (Elephas maximus) with a clinically obvious varus deformity of the carpus was examined radiographically with a standard portable x-ray unit. Several dorsopalmar radiographs were taken at a short source-to-image distance, moving the beam center along the carpus. To obtain a single image of the carpal region, radiographs were assembled digitally using a composite technique. Radiographs revealed a deviation of the limb's axis of approximately 25 degrees in the region of distal physis of the radius and ulna and a wedge-shaped epiphysis of the ulna. Healed physitis due to trauma and subluxation of the middle carpal joint are discussed as possible causes of the deformity. The radiographic technique described proved to be helpful to evaluate a relatively large anatomic area in the carpal region of an adult Asian elephant with a varus deformity and may be an alternative tool to previously described single image radiography. PMID:21370652

  1. [Radiographic disappearance of lanthanum].

    PubMed

    Pastori, Giordano

    2015-01-01

    In 2006, Cerny and Kunzendorf in the New England Journal of Medicine Images in clinical medicine, showed the radiographic appearance of lanthanum for the first time. After many years we noticed the inverse phenomenon. In a peritoneal dialysis patient treated with lanthanum carbonate, we had two radiography of the abdomen for monitoring the peritoneal catheter. In the first radiography contrast material was seen in colon. In the most recent radiography contrast material disappeared. The patient was always taking the same dose of lanthanum carbonate (1000 mg bid), although at the time of the first radiography he took the chewable tablets, for the last radiography he took the new powder formulation. We found a report in literature highlighting this phenomenon meanwhile indicating a greater chelating effect for the powder. Our hypothesis is that despite the same lanthanum dose, powder provides a greater surface area of binding and a more dispersed bowel distribution to explain a masked radio-opacity. Considering the wide availability of the powder, this must be taken into account especially in evaluating therapeutic compliance. PMID:25774580

  2. Industrial application of radiographic paper

    NASA Astrophysics Data System (ADS)

    Domanus, J. C.; Ruault, P. A.

    1980-03-01

    The paper presents the results of a comparison made among high speed Kodak Industrex D X-ray film, Industrex Instant 600 and 620, and Agfa Gevaert Structuric IC radiograph papers. It is shown that the quality of the radiographic image was tested by the use of standard and special IQIs as well as Al step wedges and artificial and natural defects. The speeds, contrasts, and exposure latitudes were calculated from the characteristic curves. An analysis is made of the quality of information available in the radiograph and the merits of the constant exposure technique are stressed. Finally, conclusions are drawn about information quality, sensitometric properties, equipment, and areas of application for radiographic paper.

  3. Radiographic findings in liveborn triploidy.

    PubMed

    Silverthorn, K G; Houston, C S; Newman, D E; Wood, B J

    1989-01-01

    The detailed radiographic features of triploidy, a fatal congenital disorder with 69 chromosomes, have not previously been reported. Radiographs of ten liveborn infants with chromosomally confirmed triploidy showed six findings highly suggestive of this diagnosis: harlequin orbits, small anterior fontanelle, gracile ribs, diaphyseal overtubulation of long bones, upswept clavicles and antimongoloid pelvis. Sixteen other less specific findings showed many similarities to those found in trisomy 18. PMID:2748230

  4. Film holder for radiographing tubing

    DOEpatents

    Davis, Earl V.; Foster, Billy E.

    1976-01-01

    A film cassette is provided which may be easily placed about tubing or piping and readily held in place while radiographic inspection is performed. A pair of precurved light-impervious semi-rigid plastic sheets, hinged at one edge, enclose sheet film together with any metallic foils or screens. Other edges are made light-tight with removable caps, and the entire unit is held securely about the object to be radiographed with a releasable fastener such as a strip of Velcro.

  5. Scanning radiographic apparatus

    SciTech Connect

    Albert, R.D.

    1980-04-01

    Visual display of dental, medical or other radiographic images is realized with an x-ray tube in which an electron beam is scanned through an x-y raster pattern on a broad anode plate, the scanning being synchronized with the x-y sweep signals of a cathode ray tube display and the intensity signal for the display being derived from a small x-ray detector which receives x-rays that have passed through the subject to be imaged. Positioning and support of the detector are provided for by disposing the detector in a probe which may be attached to the x-ray tube at any of a plurality of different locations and by providing a plurality of such probes of different configuration in order to change focal length, to accommodate to different detector placements relative to the subject, to enhance patient comfort and to enable production of both periapical images and wider angle pantomographic images. High image definition with reduced radiation dosage is provided for by a lead glass collimator situated between the x-ray tube and subject and having a large number of spaced-apart minute radiation transmissive passages convergent on the position of the detector. Releasable mounting means enable changes of collimator in conjunction with changes of the probe to change focal length. A control circuit modifies the x-y sweep signals applied to the x-ray tube and modulates electron beam energy and current in order to correct for image distortions and other undesirable effects which can otherwise be present in a scanning x-ray system.

  6. Vertical Axis Wind Turbine

    Energy Science and Technology Software Center (ESTSC)

    2002-04-01

    Blade fatigue life is an important element in determining the economic viability of the Vertical-Axis Wind Turbine (VAWT). VAWT-SAL Vertical Axis Wind Turbine- Stochastic Aerodynamic Loads Ver 3.2 numerically simulates the stochastic (random0 aerodynamic loads of the Vertical-Axis Wind Turbine (VAWT) created by the atomspheric turbulence. The program takes into account the rotor geometry, operating conditions, and assumed turbulence properties.

  7. Eliminating rib shadows in chest radiographic images providing diagnostic assistance.

    PubMed

    Oğul, Hasan; Oğul, B Buket; Ağıldere, A Muhteşem; Bayrak, Tuncay; Sümer, Emre

    2016-04-01

    A major difficulty with chest radiographic analysis is the invisibility of abnormalities caused by the superimposition of normal anatomical structures, such as ribs, over the main tissue to be examined. Suppressing the ribs with no information loss about the original tissue would therefore be helpful during manual identification or computer-aided detection of nodules on a chest radiographic image. In this study, we introduce a two-step algorithm for eliminating rib shadows in chest radiographic images. The algorithm first delineates the ribs using a novel hybrid self-template approach and then suppresses these delineated ribs using an unsupervised regression model that takes into account the change in proximal thickness (depth) of bone in the vertical axis. The performance of the system is evaluated using a benchmark set of real chest radiographic images. The experimental results determine that proposed method for rib delineation can provide higher accuracy than existing methods. The knowledge of rib delineation can remarkably improve the nodule detection performance of a current computer-aided diagnosis (CAD) system. It is also shown that the rib suppression algorithm can increase the nodule visibility by eliminating rib shadows while mostly preserving the nodule intensity. PMID:26775736

  8. Radiographic assessment of splinting bandages.

    PubMed

    Wytch, R; Ashcroft, G P; McKenzie, G; Wardlaw, D; Ledingham, W M

    1991-01-01

    The physical attenuation of X-rays by a variety of splinting bandages was measured and compared with the subjective opinion of nine radiologists. The radiolucency of the bandages and their interference with the interpretation of bony detail on radiographs (using a radiographic knee phantom) was assessed. Plaster-of-Paris (POP) bandages produced the greatest attenuation of X-rays and the greatest interference with interpretation of bony detail. All the polyurethane resin impregnated fabric bandages produced less attenuation than POP, but variations occurred due to the fabric type and knit of the bandage. The lowest attenuation occurred in those bandages using cotton, polyester or polypropylene fabric, and in all but one instance these caused least interference in radiographic interpretation. The exception was the polyester bandage, where the coarse knit of the fabric produced a large difference in X-ray beam absorption between the air spaces and the bandage. The distracting mesh pattern on the radiograph interfered with radiographic visualization. The glass fibre bandages caused intermediate attenuation, being better than POP but not as radiolucent as the non-glass fabrics. PMID:2030030

  9. Radiographic Inspection of Fueled Clads

    SciTech Connect

    Timothy J. Roney; Karen M. Wendt

    2005-04-01

    Five general purpose heat source (GPHS) fueled clads were radiographically inspected at the Idaho National Laboratory (INL). The girth weld region of each clad had previously passed visual examination, ring gauge test, and leak test but showed “positive” indications on the ultrasonic (UT) test. Positive ultrasonic indications are allowable under certain weld conditions; radiographic inspection provides a secondary nonintrusive means of clad inspection and may confirm allowable anomalies from the UT inspection. All the positive UT indications were found to exhibit allowable weld shield fusion or mismatch conditions. No indication of void defects was found. One additional clad (FCO371) was deemed unacceptable for radiographic inspection due to an unknown black substance that obscured the angular origin on the weld so that the angular offset to the UT indication could not be found.

  10. Tonsillolith: A Panoramic Radiograph Presentation

    PubMed Central

    Babu B., Balaji; Tejasvi M.L., Avinash; Avinash, C.K. Anulekha; B., Chittaranjan

    2013-01-01

    Tonsilloliths are calcifications within a tonsillar crypt, involve primarily the palatine tonsil caused by dystrophic calcification as a result of chronic inflammation. Tonsilloliths are very uncommon and are microscopic. Tonsillar concretions sometimes produce symptoms which include non-specific chronic halitosis, irritable cough, dysphagia, otalgia and foreign body-like sensation or foul taste. Patients with tonsillolithiasis may also be asymptomatic, with their lesions being discovered incidentally on panoramic radiographs. This article presents an unusual case of multiple bilateral and asymptomatic tonsilloliths which were found during a routine panoramic radiographic examination. PMID:24298535

  11. Analog enhancement of radiographic images

    NASA Technical Reports Server (NTRS)

    Baily, N. A.; Nachazel, R. J.

    1976-01-01

    The paper shows how analog methods for edge sharpening, contrast enhancement, and expansion of the range of gray levels of particular interest are effective for easy on-line application to video viewing of X-ray roentgenograms or to fluoroscopy. The technique for analog enhancement of radiographic images is a modified version of the system designed by Fuchs et al. (1972), whereby an all directional second derivative signal called detail signal is used to produce both vertical and horizontal enhancement of the image. Particular attention is given to noise filtration and contrast enhancement. Numerous radiographs supplement the text.

  12. Radiographic findings of Proteus Syndrome

    PubMed Central

    Gandhi, Nishant Mukesh; Davalos, Eric A.; Varma, Rajeev K.

    2015-01-01

    The extremely rare Proteus Syndrome is a hamartomatous congenital syndrome with substantial variability between clinical patient presentations. The diagnostic criteria consist of a multitude of clinical findings including hemihypertrophy, macrodactyly, epidermal nevi, subcutaneous hamartomatous tumors, and bony abnormalities. These clinical findings correlate with striking radiographic findings. PMID:27186241

  13. Routine radiographic assessment of the scoliotic spine.

    PubMed

    Farren, J

    1981-04-01

    This paper is designed to give a brief account of the radiographic criteria necessary in order to demonstrate and evaluate the scoliotic spine. However, additional specialised radiographic examinations, including myelography, angiography, laminography and intravenous urography are occasionally necessary. PMID:7280196

  14. Radiographic identification of loose bodies in the traumatized hip joint

    SciTech Connect

    Baird, R.A.; Schobert, W.E.; Pais, M.J.; Ahmed, M.; Wilson, W.J.; Farjalla, G.L.; Imray, T.J.

    1982-12-01

    Acrylic spacers and cubes of cortical bone of known dimensions were placed in predetermined locations in cadaver hip joints, which were then studied with plain radiography and linear, hypocycloidal, and computed tomography (CT). Joint space widening was not measurable on plain radiographs of the pelvis when 2-mm spacers were placed anywhere within the hip joint. When 4-mm spacers were used, widening measured 2 mm in the axis of measurement corresponding to the location of the spacer. Linear tomography did not permit identification of the 2-mm cubes; however, hypocycloidal tomography and CT consistently showed them anywhere within the hip joint. Radiation dose and clinical recommendations are discussed.

  15. Radiographic amplifier screens: Fabrication process and characteristics

    NASA Technical Reports Server (NTRS)

    Szepesi, Z. P.

    1977-01-01

    The fabrication process and transfer characteristics for solid state radiographic image transducers (radiographic amplifier screens) is described. These screens were developed for use in real time nondestructive evaluation procedures that require large format radiographic images with contrast and resolution capabilities unavailable with conventional fluoroscopic screens. This work was directed toward screens usable for inmotion, on-line radiographic inspection by means of closed circuit television.

  16. 21 CFR 892.1840 - Radiographic film.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Radiographic film. 892.1840 Section 892.1840 Food... DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1840 Radiographic film. (a) Identification. Radiographic film is a device that consists of a thin sheet of radiotransparent material coated on one or...

  17. Radiographic instrumentation for DPM experiments

    NASA Technical Reports Server (NTRS)

    Fripp, Archie L.; Debnam, W. J.; Simchick, Richard T.; Barber, P. G.

    1990-01-01

    New developments in x-ray radiography that may be applicable to containerless experimentation are presented. The two features discussed are the use of radiography to determine the position and shape of the solid-liquid interface and, with the aid of appropriate markers, the flow patterns in either the surface or bulk of the liquid state. Both surface energy and fluid viscosity measurements can be made with the aid of the described radiographic system.

  18. Non-Radiographic Axial Spondyloarthritis.

    PubMed

    Slobodin, Gleb; Eshed, Iris

    2015-12-01

    The term non-radiographic axial spondyloarthritis (nrAxSpA) was coined for patients who have a clinical picture of ankylosing spondylitis (AS) but do not exhibit radiographic sacroiliitis. The ASAS classification criteria for nrAxSpA, ensuring the recruitment of homogenous study cohorts, were accepted in 2009, although the respective diagnostic criteria for daily clinical practice have not yet been developed. The clinical diagnosis should be based on the composite of clinical symptoms and signs of the disease, HLA B27 status, and magnetic resonance imaging (MRI) of sacroiliac joints. Notably, a negative MRI or HLA B27 does not exclude the diagnosis in patients with a high clinical suspicion for nrAxSpA. The prevalence of nrAxSpA is similar to that of AS, but the former has a higher female preponderance. The rate of progression of nrAxSpA to the radiographic stage of disease (AS) ranges from 10% to 20% over 2 years. Current treatment strategies for nrAxSpA are the same as for AS and include non-steroidal anti-inflammatory drugs and inhibitors of tumor necrosis factor-alpha. While this review summarizes the current achievements in the field of nrAxSpA, further understanding of the epidemiology and natural history of the disease and, particularly, mechanisms of inflammation and subsequent new bone formation is essential for the development of new treatment strategies for nrAxSpA patients. PMID:26897981

  19. RADIOGRAPHIC RESULTS FROM THE NTLX SERIES OF HYDRODYNAMIC EXPERIMENTS

    SciTech Connect

    R.T. OLSON; D.M. ORO; ET AL

    2001-06-01

    The NTLX series of experiments are focused on measuring the shock induced hydrodynamic flow of a Sn-PMMA target. For these experiments multi-frame flash X-ray radiography is used to measure the position of the Sn-PMMA target interface and the location of shock in the PMMA as a function of time. Four radiographs are acquired at 700 ns intervals having a line-of-sight following the target's axis of symmetry. Because the X-ray spectrum from the sources has an end-point energy of {approx}300 keV with a strong component of {approx}60 keV tungsten K-line radiation, the Sn portion of the target is radiographically opaque. However, X-rays are transmitted through the PMMA portion of the target thereby allowing motion of the Sn-PMMA interface to be imaged. Also, the shock location is tracked as a function of time due to the density increase in the shocked PMMA. The resulting radiographs are analyzed to provide the trajectory and shape of both the shock and Sn-PMMA interface. In addition, the shock velocity in the Sn is determined for asymmetric target geometries.

  20. Radiographic results from the NTLX series of hydrodynamic experiments

    SciTech Connect

    Olson, R. T.; Oro, D. M.; Anderson, B. G.; Studebaker, J. K.; Alvey, K.; Peterson, K.; Froggett, B. C.

    2001-01-01

    The NTLX series of experiments are focused on measuring the shock induced hydrodynamic flow of a Sn-PMMA target. For these experiments multi-frame flash X-ray radiography is used to measure the position of the Sn-PMMA target interface and the location of shock in the PMMA as a function of time. Four radiographs are acquired at 700 ns intervals having a line-of-sight following the target's axis of symmetry. Because the Xray spectrum from the sources has an end-point energy of {approx}300 keV with a strong component of {approx}60 keV tungsten K-line radiation, the Sn portion of the target is radiographically opaque. However, X-rays are transmitted through the PMMA portion of the target thereby allowing motion of the Sn-PMMA interface to be imaged. Also, the shock location is tracked as a function of time due to the density increase in the shocked PMMA. The resulting radiographs are analyzed to provide the trajectory and shape of both the shock and Sn-PMMA interface. In addition, the shock velocity in the Sn is determined for asymmetric target geometries.

  1. Design and performance of the marx generator for the darht second axis electron injector.

    SciTech Connect

    Nielsen, K.; McVuistian, B.; Fockler, J.; Yu, S.; Carboni, V.; Corcoran, P.; Douglas, J.; Eichenberger, C.; Harris, G.; Lackner, H.; Morton, D.

    2003-06-12

    The injector for the second axis of the Dual-Axis Radiographic Hydrotest Facility (DARHT II) is now undergoing commissioning tests at Los Alamos National Laboratory. A Marx generator develops a 3.2 MV, 2 μs pulse that is applied to the diode through a high voltage (or Marx) dome, current stalk and high voltage insulator column. The 2 kA electron beam source is a 165-mm-diameter thermionic dispenser cathode operating near 120 kV/cm. The extracted beam enters a series of eight pulsed power-driven injector induction cells that accelerate the beam to approximately 4.5 MeV. The beam then passes through a beamhead clean-up zone (BCUZ) to "scrape off" the off-energy portion of the beam (the beam leading edge and, to a lesser extent, the beam trailing edge). A crowbar switch fixed at the end of 2 μs produces a short fall time. This paper focuses on the electrical and mechanical design and testing of the Marx generator. The Marx consists of 88 stages, each half stage of which is a +/- 50 kV type E PFN. The Marx was tested for over 8000 shots before shipment to Los Alamos and demonstrated 6 ns jitter and good reliability with only 8 prefires out of 5000 shots. At the end of December 2002, nearly 800 shots have been fired in the process of commissioning the DARHT machine. The results of both series of these tests are given in this paper.

  2. Do we need hip-ankle radiographs to assess the coronal alignment and implant position after total knee replacement?

    PubMed Central

    Dargel, Jens; Oppermann, Johannes; Eysel, Peer; Penning, Lenhard

    2016-01-01

    Aims and Objectives: Restoration of the coronal alignment of the knee is known to be one of the major criteria of a successful total knee arthroplasty (TKA). It therefore appears to be mandatory to routinely assess the postoperative limb alignment using hip-ankle radiographs and to identify implants that may be at risk of premature failure. However, there is no clear consensus whether weight-bearing hip-ankle radiographs or rather standardized a-p knee-radiographs should be used to assess implant position and coronal alignment after TKA. It is the aim of the present study to investigate if implant position and the mechanical alignment after TKA can reproducibly be assessed using standardized a-p knee-radiographs or rather if weight-bearing hip-ankle radiographs are needed. Materials and Methods: This study was performed on 100 postoperative weight-bearing hip-ankle radiographs after conventional primary TKA. The true mechanical and anatomical femorotibial angle as well as coronal implant position (MPTA, LDFA) was assessed using the MediCAD software, which served as a control. The hip-ankle radiographs were then digitally cropped to 80%, 60% and 40% of the leg-length. In each cropped radiograph, tibial coronal implant position was assessed by referencing against the visible mid-shaft, whereas femoral implant position was referenced against the visible mid-shaft (anatomical axis) or against a surrogate mechanical axis, which was drawn perpendicular to the distal tangent of the femoral component. Each measurement was performed by three independent observers. The difference between the alignment parameters in the hip-ankle radiographs were statistically compared with the cropped radiographs and the inter-observer correlation coefficient (ICC) was calculated for each parameter. Results: The ICC for inter-observer agreement of measurement of the mechanical femorotibial angle was significantly higher in hip-ankle radiographs (.95) when compared with a radiograph cropped

  3. Dual aperture multispectral Schmidt objective

    NASA Technical Reports Server (NTRS)

    Minott, P. O. (Inventor)

    1984-01-01

    A dual aperture, off-axis catadioptic Schmidt objective is described. It is formed by symmetrically aligning two pairs of Schmidt objectives on opposite sides of a common plane (x,z). Each objective has a spherical primary mirror with a spherical focal plane and center of curvature aligned along an optic axis laterally spaced apart from the common plane. A multiprism beamsplitter with buried dichroic layers and a convex entrance and concave exit surfaces optically concentric to the center of curvature may be positioned at the focal plane. The primary mirrors of each objective may be connected rigidly together and may have equal or unequal focal lengths.

  4. Adult Hirschprung disease: radiographic findings.

    PubMed

    Mindelzun, R E; Hicks, S M

    1986-09-01

    Hirschprung disease is usually diagnosed in infancy. Occasionally patients reach adulthood without diagnosis or treatment. Four cases of adult Hirschprung disease are described. The principal radiographic findings are a markedly dilated, feces-filled colon above the zone of transition; a narrowed rectum; a cone- or funnel-shaped zone of transition; and a mosaic colonic pattern caused by collapsed redundant mucosa after colonic cleansing. In an adult, identification on a barium enema examination of an abrupt, smooth transition zone in the rectum with proximal colonic dilatation, in conjunction with an appropriate clinical history, should suggest the diagnosis of adult Hirschprung disease. PMID:3737900

  5. Early radiographic changes in radiation bone injury

    SciTech Connect

    Fujita, M.; Tanimoto, K.; Wada, T.

    1986-06-01

    A chronologic series of periapical radiographs was evaluated for the purpose of detecting damage to bone and tooth-supporting tissues in a patient receiving radiation therapy for a basal cell carcinoma of the mandibular gingiva. Widening of the periodontal space was one of the early radiographic changes observed. It is suggested, from the sequence of radiographic changes, that radiation-induced changed in the circulatory system of the bone might be primarily responsible for the resulting changes.

  6. Photographic Effect Of Darkroom Exposure On Radiographs

    NASA Astrophysics Data System (ADS)

    Bollen, R. H.

    1982-12-01

    Fogging of radiographic films can be characterized by a photographically equivalent radiographic exposure dose (Ex-eq). It is shown that within the limits of the experiments Ex-eq is independent of the moment of fogging i.e. before or after the radiographic imaging, and of the radiation intensity levels in the radiographic beam in case of no-screenexposure, but is dependent in case of an exposure with fluorescent screens and fogging by light. A dependent Ex-eq causes apparent sensitometric anomalies. The study warns against darkroom light fogging mainly when unloading cassettes.

  7. Reliability of the Radiographic Sagittal and Frontal Tibiotalar Alignment after Ankle Arthrodesis

    PubMed Central

    Willegger, Madeleine; Holinka, Johannes; Nemecek, Elena; Bock, Peter; Wanivenhaus, Axel Hugo; Windhager, Reinhard; Schuh, Reinhard

    2016-01-01

    Background Accurate measurement of the tibiotalar alignment is important in radiographic outcome assessment of ankle arthrodesis (AA). In studies, various radiological methods have been used to measure the tibiotalar alignment leading to facultative misinterpretation of results. However, to our knowledge, no previous study has investigated the reliability of tibiotalar alignment measurement in AA. We aimed to investigate the reliability of four different methods of measurement of the frontal and sagittal tibiotalar alignment after AA, and to further clarify the most reliable method for determining the longitudinal axis of the tibia. Methods Thirty-eight weight bearing anterior to posterior and lateral ankle radiographs of thirty-seven patients who had undergone AA with a two screw fixation technique were selected. Three observers measured the frontal tibiotalar angle (FTTA) and the sagittal tibiotalar angle (STTA) using four different methods. The methods differed by the definition of the longitudinal tibial axis. Method A was defined by a line drawn along the lateral tibial border in anterior to posterior radiographs and along the posterior tibial border in lateral radiographs. Method B was defined by a line connecting two points in the middle of the proximal and the distal tibial shaft. Method C was drawn „freestyle”along the longitudinal axis of the tibia, and method D was defined by a line connecting the center of the tibial articular surface and a point in the middle of the proximal tibial shaft. Intra- and interobserver correlation coefficients (ICC) and repeated measurement ANOVA were calculated to assess measurement reliability and accuracy. Results All four methods showed excellent inter- and intraobserver reliability for the FTTA and the STTA. When the longitudinal tibial axis is defined by connecting two points in the middle of the proximal and the distal tibial shaft, the highest interobserver reliability for the FTTA (ICC: 0.980; CI 95%: 0.966–0

  8. Observer POD for radiographic testing

    SciTech Connect

    Kanzler, Daniel E-mail: uwe.ewert@bam.de Ewert, Uwe E-mail: uwe.ewert@bam.de Müller, Christina E-mail: uwe.ewert@bam.de; Pitkänen, Jorma

    2015-03-31

    The radiographic testing (RT) is a non-destructive testing (NDT) method capable of finding volumetric and open planar defects depending on their orientation. The radiographic contrast is higher for larger penetrated length of the defect in a component. Even though, the detectability of defects does not only depend on the contrast, but also on the noise, the defect area and the geometry of the defect. The currently applied Probability of Detection (POD) approach uses a detection threshold that is only based on a constant noise level or on a constant contrast threshold. This does not reflect accurately the results of evaluations by human observers. A new approach is introduced, using the widely applied POD evaluation and additionally a detection threshold depending on the lateral area and shape of the indication. This work shows the process of calculating the POD curves with simulated data by the modeling software aRTist and with artificial reference data of different defect types, such as ASTM E 476 EPS plates, flat bottom holes and notches. Additional experiments with different operators confirm that the depth of a defect, the lateral area and shape of its indication contribute with different weight to the detectability of the defect if evaluated by human operators on monitors.

  9. Observer POD for radiographic testing

    NASA Astrophysics Data System (ADS)

    Kanzler, Daniel; Ewert, Uwe; Müller, Christina; Pitkänen, Jorma

    2015-03-01

    The radiographic testing (RT) is a non-destructive testing (NDT) method capable of finding volumetric and open planar defects depending on their orientation. The radiographic contrast is higher for larger penetrated length of the defect in a component. Even though, the detectability of defects does not only depend on the contrast, but also on the noise, the defect area and the geometry of the defect. The currently applied Probability of Detection (POD) approach uses a detection threshold that is only based on a constant noise level or on a constant contrast threshold. This does not reflect accurately the results of evaluations by human observers. A new approach is introduced, using the widely applied POD evaluation and additionally a detection threshold depending on the lateral area and shape of the indication. This work shows the process of calculating the POD curves with simulated data by the modeling software aRTist and with artificial reference data of different defect types, such as ASTM E 476 EPS plates, flat bottom holes and notches. Additional experiments with different operators confirm that the depth of a defect, the lateral area and shape of its indication contribute with different weight to the detectability of the defect if evaluated by human operators on monitors.

  10. Digital processing of radiographic images

    NASA Technical Reports Server (NTRS)

    Bond, A. D.; Ramapriyan, H. K.

    1973-01-01

    Some techniques are presented and the software documentation for the digital enhancement of radiographs. Both image handling and image processing operations are considered. The image handling operations dealt with are: (1) conversion of format of data from packed to unpacked and vice versa; (2) automatic extraction of image data arrays; (3) transposition and 90 deg rotations of large data arrays; (4) translation of data arrays for registration; and (5) reduction of the dimensions of data arrays by integral factors. Both the frequency and the spatial domain approaches are presented for the design and implementation of the image processing operation. It is shown that spatial domain recursive implementation of filters is much faster than nonrecursive implementations using fast fourier transforms (FFT) for the cases of interest in this work. The recursive implementation of a class of matched filters for enhancing image signal to noise ratio is described. Test patterns are used to illustrate the filtering operations. The application of the techniques to radiographic images of metallic structures is demonstrated through several examples.

  11. Multiple axis reticle

    NASA Astrophysics Data System (ADS)

    Barns, Chris E.; Gunter, William D.

    1990-09-01

    A reticle permits the alignment of three orthogonal axes (X, Y and Z) that intersect at a common target point. Thin, straight filaments are supported on a frame. The filaments are each contained in a different orthogonal plane (S sub xy, S sub xz, and S sub yz) and each filament intersects two of the three orthogonal axes. The filaments, as viewed along the frame axis, give the appearance of a triangle with a V extending from each triangle vertex. When axial alignment is achieved, the filament portions adjacent to a triangle vertex are seen (along the axis of interest) as a right-angle cross, whereas these filament portions are seen to intersect at an oblique angle when axial misalignment occurs. The reticle is open in the region near the target point leaving ample space for alignment aids such as a pentaprism or a cube mirror.

  12. An auditory display in a dual-axis tracking task.

    NASA Technical Reports Server (NTRS)

    Mirchandani, P. B.

    1972-01-01

    Results of a study in which subjects were presented concurrently with the primary task of controlling a second-order plant and the secondary task of controlling a first-order plant. The plant errors for the two tasks were shown on separate visual displays. An auditory display, whose output varied in frequency and volume with the error, was used to supplement the secondary task in half of the runs. To study the effects of the auditory display, two performance measures were obtained: (1) the integral of the squared error (ISE) and (2) the describing functions of the human operator. Statistical analysis of the ISE measures indicated that when the secondary task was supplemented with an auditory display, there was a significant improvement in performance on the secondary task. The performance on the primary task improved on the average, but not significantly. The variances of the ISE values decreased for both the tasks, indicating a more consistent behavior with the auditory display. The describing function analysis showed that supplementing the secondary task with the auditory display increased the low frequency gain of the human operator for this task. The describing functions for the primary task did not show any apparent changes.

  13. National Wind Tecnology Center Provides Dual Axis Resonant Blade Testing

    ScienceCinema

    Felker, Fort

    2014-06-10

    NREL's Structural Testing Laboratory at the National Wind Technology Center (NWTC) provides experimental laboratories, computer facilities for analytical work, space for assembling components and turbines for atmospheric testing as well as office space for industry researchers. Fort Felker, center director at the NWTC, discusses NREL's state-of-the-art structural testing capabilities and shows a flapwise and edgewise blade test in progress.

  14. National Wind Tecnology Center Provides Dual Axis Resonant Blade Testing

    SciTech Connect

    Felker, Fort

    2013-11-13

    NREL's Structural Testing Laboratory at the National Wind Technology Center (NWTC) provides experimental laboratories, computer facilities for analytical work, space for assembling components and turbines for atmospheric testing as well as office space for industry researchers. Fort Felker, center director at the NWTC, discusses NREL's state-of-the-art structural testing capabilities and shows a flapwise and edgewise blade test in progress.

  15. 21 CFR 892.1840 - Radiographic film.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Radiographic film. 892.1840 Section 892.1840 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1840 Radiographic film. (a)...

  16. 21 CFR 892.1840 - Radiographic film.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic film. 892.1840 Section 892.1840 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1840 Radiographic film. (a)...

  17. 21 CFR 892.1840 - Radiographic film.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Radiographic film. 892.1840 Section 892.1840 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1840 Radiographic film. (a)...

  18. 21 CFR 892.1840 - Radiographic film.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Radiographic film. 892.1840 Section 892.1840 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1840 Radiographic film. (a)...

  19. Doping explosive materials for neutron radiographic enhancement.

    NASA Technical Reports Server (NTRS)

    Golliher, K. G.

    1971-01-01

    Discussion of studies relating to the selection of doping materials of high neutron absorption usable for enhancing the neutron radiographic imaging of explosive mixtures, without interfering with the proper chemical reaction of the explosives. The results of the studies show that gadolinium oxide is an excellent material for doping explosive mixtures to enhance the neutron radiographic image.

  20. [Allergy to radiographic contrast media].

    PubMed

    Vionnet, Julien; Petitpierre, Stéphanie; Fumeaux, Alexandre; Meuli, Reto; Spertini, Francois; Comte, Denis

    2013-04-17

    Allergy to radiographic contrast media Hypersensitivity reactions to radio-contrast media are common in the daily practice. These products are responsible for immediate (< or = 1 hour after administration) and non immediate (> 1 hour after administration) hypersensitivity reactions. A diagnostic work-up by an allergologist with skin tests and in some cases provocation tests is of value in reducing the risk of recurrent hypersensitivity reactions to iodinated contrast media. A careful selection of the patients is required because the incidence of breakthrough reactions is still concerning, even with proper premedication. Practical recommendations are presented in this article. For gadolinium-based contrast agents, data in the literature is not sufficient for suggesting guidelines. PMID:23667970

  1. Single Axis Piezoceramic Gimbal

    NASA Technical Reports Server (NTRS)

    Horner, Garnett C.; Taleghani, Barmac K.

    1999-01-01

    This paper describes the fabrication, testing, and analysis of a single axis piezoceramic gimbal. The fabrication process consist of pre-stressing a piezoceramic wafer using a high-temperature thermoplastic polyimide and a metal foil. The differential thermal expansion between the ceramic and metal induces a curvature. The pre-stressed, curved piezoceramic is mounted on a support mechanism and a mirror is attached to the piezoceramic. A plot of gimbal angle versus applied voltage to the piezoceramic is presented. A finite element analysis of the piezoceramic gimbal is described. The predicted gimbal angle versus applied voltage is compared to experimental results.

  2. Single Axis Piezoceramic Gimbal

    NASA Technical Reports Server (NTRS)

    Horner, Garnett; Taleghani, Barmac

    2001-01-01

    This paper describes the fabrication, testing, and analysis of a single axis piezoceramic gimbal. The fabrication process consists of pre-stressing a piezoceramic wafer using a high-temperature thermoplastic polyimide and a metal foil. The differential thermal expansion between the ceramic and metal induces a curvature. The pre-stressed, curved piezoceramic is mounted on a support mechanism and a mirror is attached to the piezoceramic. A plot of gimbal angle versus applied voltage to the piezoceramic is presented. A finite element analysis of the piezoceramic gimbal is described. The predicted gimbal angle versus applied voltage is compared to experimental results.

  3. Vertical axis wind turbines

    DOEpatents

    Krivcov, Vladimir; Krivospitski, Vladimir; Maksimov, Vasili; Halstead, Richard; Grahov, Jurij

    2011-03-08

    A vertical axis wind turbine is described. The wind turbine can include a top ring, a middle ring and a lower ring, wherein a plurality of vertical airfoils are disposed between the rings. For example, three vertical airfoils can be attached between the upper ring and the middle ring. In addition, three more vertical airfoils can be attached between the lower ring and the middle ring. When wind contacts the vertically arranged airfoils the rings begin to spin. By connecting the rings to a center pole which spins an alternator, electricity can be generated from wind.

  4. Comparison of radiographic image characteristics of Brånemark and IMZ implants.

    PubMed

    Sewerin, I P

    1991-01-01

    A Brånemark standard titanium implant and an IMZ plasma flame spray-coated implant were radiographed experimentally under standardized circumstances. Angulations in relation to film plane and central X-ray as well as rotations around the implant's longitudinal axis were varied. The influence of implant architecture on image density and image pattern was analyzed and images of the two types of implants were compared. The Brånemark implant is asymmetric and exhibits only radiographic burnout in its apical area. The 4 vertical apical cuts cause very distracting images and leave the impression that the implant is conical. It is possible to evaluate angulations with great accuracy from the thread profile, but there are limited possibilities for estimation of rotational stages. The IMZ implant shows symmetric images in any projection. The 4 vertical slits cause a disturbing burnout in the central part of the implant in certain views, and radiographic images are very inconstant. Possibilities of estimating angulation and rotation are varying. Differences in radiographic image characteristics are supposed to influence diagnostic yield as they affect the possibilities of identifying osseointegration radiographically and of controlling image identity in serial radiography. PMID:1843469

  5. A computation method of dual-material separation based on dual-energy CT imaging

    NASA Astrophysics Data System (ADS)

    Zou, Jing; Chen, Ming; Zhao, Jintao; Lv, Hanyu; Hu, Xiaodong

    2015-10-01

    Dual-energy x-ray technique, which consists in combining two radiographs acquired at two kilovoltage, can improve the identity of the compositions of object over regular CT, or at least improve image contrast. Dual-energy equations can be easily written and solved for ideally monochromatic x-ray source and perfect detector, but become complex when considering polychromatic x-ray source, detector sensitivity, and system non-linearity. In this paper, a new dual-energy algorithm which employed the basis material decomposition method was investigated for improving material separation capability. Studies by using computer-simulated data were performed to validate and evaluate the algorithm. The preliminary results of the study show that, with the proposed algorithm, separated "material specific" images of dual-material object could be obtained. Also monochromatic image can be acquired at arbitrary desired energy which could enhance image contrast in comparison with conventional reconstructed image.

  6. Semimajor Axis Estimation Strategies

    NASA Technical Reports Server (NTRS)

    How, Jonathan P.; Alfriend, Kyle T.; Breger, Louis; Mitchell, Megan

    2004-01-01

    This paper extends previous analysis on the impact of sensing noise for the navigation and control aspects of formation flying spacecraft. We analyze the use of Carrier-phase Differential GPS (CDGPS) in relative navigation filters, with a particular focus on the filter correlation coefficient. This work was motivated by previous publications which suggested that a "good" navigation filter would have a strong correlation (i.e., coefficient near -1) to reduce the semimajor axis (SMA) error, and therefore, the overall fuel use. However, practical experience with CDGPS-based filters has shown this strong correlation seldom occurs (typical correlations approx. -0.1), even when the estimation accuracies are very good. We derive an analytic estimate of the filter correlation coefficient and demonstrate that, for the process and sensor noises levels expected with CDGPS, the expected value will be very low. It is also demonstrated that this correlation can be improved by increasing the time step of the discrete Kalman filter, but since the balance condition is not satisfied, the SMA error also increases. These observations are verified with several linear simulations. The combination of these simulations and analysis provide new insights on the crucial role of the process noise in determining the semimajor axis knowledge.

  7. Digital radiographic localization for CT scanning of the larynx

    SciTech Connect

    Silverman, P.M.; Korobkin, M.; Rauch, R.F.

    1983-12-01

    Computed tomography (CT) of the larynx is the preferred method for staging laryngeal carcinoma and assessing the extent of injury from trauma. The standard method of examination consists of 5 mm contiguous scans throughout the larynx in quiet respiration. Scans are performed with the patient supine with the neck slightly extended allowing the long axis of the larynx to be perpendicular to the scanning plane. A complete examination requires scanning from the supraglottic region (level of hyoid bone) to the subglottic region (level of cricoid cartlage). In the authors' experience when this method is used, multiple scans are performed cephalad to the level of interest because no upper limit of the examination is established before transaxial scans are done. We have used the lateral digital radiograph of the neck to identify specific landmarks so that the upper and lower limets of the examination can be established before scanning.

  8. End-to-End Radiographic Systems Simulation

    SciTech Connect

    Mathews, A.; Kwan, T.; Buescher, K.; Snell, C.; Adams, K.

    1999-07-23

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this project was to develop a validated end-to-end radiographic model that could be applied to both x-rays and protons. The specific objectives were to link hydrodynamic, transport, and magneto-hydrodynamic simulation software for purposes of modeling radiographic systems. In addition, optimization and analysis algorithms were to be developed to validate physical models and optimize the design of radiographic facilities.

  9. Radiographic findings in congenital lead poisoning

    SciTech Connect

    Pearl, M.; Boxt, L.M.

    1980-07-01

    Because lead crosses the placenta throughout pregnancy, the fetus is at risk for lead poisoning. A full term, asymptomatic child was born with congenital lead poisoning secondary to maternal pica. Radiographic findings of a dense cranial vault, lead lines, and delayed skeletal and deciduous dental development were noted at birth. After chelation therapy, when the patient was seven months old, radiographs revealed normal skeletal maturation. Tooth eruption did not occur until 15 months of age. Newborn infants with these radiographic findings should be screened for subclinical, congenital lead poisoning.

  10. [The dental radiograph: pitfalls and surprises].

    PubMed

    Bakx, S; Syriopoulos, K

    2015-05-01

    Guidelines allow retakes of dental radiographs of up to 10%. In the general practice the percentage of retakes is considerably higher. In intraoral radiography film positioning and faults in directing the collimator are the most common reasons for retakes. The use of film holders and correctly aiming the collimator decrease the risk of failure. In panoramic radiography the positioning of the patient in the x-ray machine and the palatoglossal air space are the main causes of failure of radiographs. A systematic approach, a thorough check of the radiation area for artefacts and the use of the available laser lines decrease the risk of a diagnostically unacceptable radiograph. PMID:26210220

  11. Mastitis, a Radiographic, Clinical, and Histopathologic Review.

    PubMed

    Cheng, Lin; Reddy, Vijaya; Solmos, Gene; Watkins, Latanja; Cimbaluk, David; Bitterman, Pincas; Ghai, Ritu; Gattuso, Paolo

    2015-01-01

    Mastitis is a benign inflammatory process of the breast with heterogeneous histopathological findings, which clinically and radiographically may mimic a mammary carcinoma. We undertook a retrospective study on 37 cases of mastitis in our institution to correlate the radiographic imaging features and the clinical presentation with the histopathological findings. Histologically, there were 21 granulomatous, 7 fibrous, 3 plasma cell, 3 lupus, 2 lymphocytic, and 1 case of acute mastitis. Radiographically, 16/25 (64%) patients with ultrasound studies showed irregular hypoechoic masses suspicious for malignancy. Clinically, 38% of patients had an associated systemic disease. PMID:25940456

  12. Research on calibration method of axis-shift multi-camera for aerial photogrammetry

    NASA Astrophysics Data System (ADS)

    Wang, Xiao; Fang, Junyong; Ma, Jingyu; Zhang, Xiaohong; Zhao, Dong; Liu, Xue

    2015-12-01

    Axis-shift multi-camera has been gradually applied in the aerial photogrammetry because of its advantages on structure design. In this paper, the basic axis-shift theory is analyzed, and an improved calibration method is described. A prototype system, including two axis-shift cameras, is developed to validate the feasibility and correctness of the proposed method. With the help of a high-precision indoor control field, the parameters of single camera and the relative orientation parameters of the dual camera system are calculated respectively. Experiment result indicates that this calibration method is suitable for the axis-shift multi camera system.

  13. Bacterial adherence and contamination during radiographic processing.

    PubMed

    Bachman, C E; White, J M; Goodis, H E; Rosenquist, J W

    1990-11-01

    Oral fluids are potential contaminants of radiographic processors. This investigation measured bacterial contamination in a radiographic processing room during times of high and low clinical activity and processing effects on five types of microorganisms. Cultures in the clinical setting, during high and low activity, were taken by brain-heart infusion agar plates placed near automatic processors. Site samples were taken of entrance, developer, fixer, water, and exit surfaces. Measurements of processing effects were accomplished by intentional contamination of films run in series through an automatic processor. Site samples were again taken of the processor. In the clinical setting colony-forming units increased with activity. Radiographic processing after intentional contamination decreased colony-forming units on films, but they increased for all processing solutions. Bacteria on radiographic film survived processing. Although processing procedures significantly reduce the number of bacteria on films, the potential for contamination and cross-contamination remains. PMID:2122350

  14. Radiographic Kinetics of Sarcomatoid Renal Cell Carcinoma.

    PubMed

    Syed, Ali; Raval, Amar; Pridjian, Andrew; Birbe, Ruth; Trabulsi, Edouard J

    2016-07-01

    Renal cell carcinoma is a common entity often managed surgically with excellent survival benefits. We report a rare case of sarcomatoid renal cell carcinoma with aggressive growth kinetics after palliative resection captured radiographically. PMID:27041470

  15. Solid state radiographic image amplifiers, part C

    NASA Technical Reports Server (NTRS)

    Szepesi, Z.

    1971-01-01

    The contrast sensitivity of the radiographic amplifiers, both the storage type and nonstorage type, their absolute sensitivity, and the reproducibility of fabrication were investigated. The required 2-2T quality level was reached with the radiographic storage screen. The sensitivity threshold was 100 to 200 mR with 45 to 100 kV filtered X-rays. The quality level of the radiographic amplifier screen (without storage) was 4-4T; for a 6 mm (0.25 in.) thick aluminum specimen, a 1 mm (0.040 in.) diameter hole in a 0.25 mm (0.010 in.) thick penetrameter was detected. Its sensitivity threshold was 2 to 6 mR/min. The developed radiographic screens are applicable for uses in nondestructive testing.

  16. Film adhesive enhances neutron radiographic images

    NASA Technical Reports Server (NTRS)

    Reed, M. W.

    1978-01-01

    Resolution of neutron radiographic images of thermally conductive film is increased by replacing approximately 5 percent of aluminum powder, which provides thermal conductivity, with gadolinium oxide. Oxide is also chemically stable.

  17. Verifying X-Radiographs With Computed Tomographs

    NASA Technical Reports Server (NTRS)

    Roy, Jagatjit; Pascua, Antonio G.

    1991-01-01

    Nondestructive technique gives added confidence in inspection. Ambiguous indications in radiographic inspections of metal castings checked by computed tomography. Fast and inexpensive conventional x-ray inspection used to make film image of overall casting, and slower, more costly computed tomography used to reinspect relatively few parts of casting presenting possible diffraction patterns or other difficult-to-interpret features. Method effective in resolving ambiguities in radiographs of turbine blades. Provides same information as metallurgical sectioning.

  18. Radiation recommendation series: administratively required dental radiographs

    SciTech Connect

    Not Available

    1981-09-01

    Administrative requirements for radiographs are found in many segments of the United States health care system. This document presents an FDA radiation recommendation on administratively required dental x-ray examinations. In general, such examinations are not requested to further the patient's dental health, but rather as a means of monitoring claims. However, the administrative use of radiographs that have been taken in the normal course of patient care is usually appropriate, as long as the patient's right to privacy is respected.

  19. [Indications for and frequency of intraoral radiographs].

    PubMed

    Poorterman, J H G

    2015-05-01

    Radiographs are essential in dental practice today. Due to the exposure of patients to X-rays every radiograph has to be justified. The advantages and disadvantages of risks and diagnostic rewards have to be weighed against one another whenever X-ray imaging is considered. An important factor in this respect is the usefulness (in terms of sensitivity and specificity) of a radiograph and along with that, the monitoring of the quality of the entire process, from positioning the photo up to and including the development or scanning of it. Both for children and adults the indication for taking radiographs must be made on an individual basis. The most important considerations are: caries experience, oral hygiene and nutritional habits and exposure to fluorides. Based on these factors an individual risk assessment can be made and the possible benefit of bitewing radiographs for the dental treatment can be determined. European guidelines give advice on the indications and frequency of radiographs in, among other fields, periodontology, endodontology and implantology. PMID:26210219

  20. The 'ABC' of examining foot radiographs.

    PubMed Central

    Pearse, Eyiyemi O.; Klass, Benjamin; Bendall, Stephen P.

    2005-01-01

    INTRODUCTION: We report a simple systematic method of assessing foot radiographs that improves diagnostic accuracy and can reduce the incidence of inappropriate management of serious forefoot and midfoot injuries, particularly the Lisfranc-type injury. STUDY GROUP AND METHODS: Five recently appointed senior house officers (SHOs), with no casualty or Orthopaedic experience prior to their appointment, were shown a set of 10 foot radiographs and told the history and examination findings recorded in the casualty notes of each patient within 6 weeks of taking up their posts. They were informed that the radiographs might or might not demonstrate an abnormality. They were asked to make a diagnosis and decide on a management plan. The test was repeated after they were taught the 'ABC' method of evaluating foot radiographs. RESULTS: Diagnostic accuracy improved after SHOs were taught a systematic method of assessing foot radiographs. The proportion of correct diagnoses increased from 0.64 to 0.78 and the probability of recognising Lisfranc injuries increased from 0 to 0.6. CONCLUSIONS: The use of this simple method of assessing foot radiographs can reduce the incidence of inappropriate management of serious foot injuries by casualty SHOs, in particular the Lisfranc type injury. PMID:16263015

  1. Work related respiratory symptoms in radiographers.

    PubMed Central

    Smedley, J; Inskip, H; Wield, G; Coggon, D

    1996-01-01

    OBJECTIVE--To determine the prevalence of work related symptoms among radiographers compared with a control group of physiotherapists. METHOD--A postal questionnaire was used to collect information from radiographers and physiotherapists who registered in the United Kingdom during 1985-9. RESULTS--Satisfactory questionnaires were returned by 2354 (65%) of the radiographers and 3048 (69%) of the physiotherapists. There was a clear excess of work related symptoms among the radiographers. In particular, they were more likely to complain of symptoms that were worse at work, mouth soreness, sore, itchy, or runny eyes, persistent blocked nose, persistent itchy nose or sneezing, sore throat, headache, and of lower respiratory tract symptoms, which were also worse on workdays. These symptoms were associated particularly with the use of automatic processing machines. 235 radiographers gave a history of wheeze or chest tightness that had been worse at work or on days when at work. CONCLUSIONS--Work related symptoms suggesting irritation of the eyes and upper airways were more common in radiographers than controls, and may be related to exposure to x ray film processing chemicals. Men and women who reported work related wheeze or chest tightness will be followed up in more detail to assess the prevalence of occupational asthma in the cohort. PMID:8704868

  2. X-ray radiographic technique for measuring density uniformity of silica aerogel

    NASA Astrophysics Data System (ADS)

    Tabata, Makoto; Hatakeyama, Yoshikiyo; Adachi, Ichiro; Morita, Takeshi; Nishikawa, Keiko

    2013-01-01

    This paper proposes a new X-ray radiographic technique for measuring density uniformity of silica aerogels used as radiator in proximity-focusing ring-imaging Cherenkov detectors. To obtain high performance in a large-area detector, a key characteristic of radiator is the density (i.e. refractive index) uniformity of an individual aerogel monolith. At a refractive index of n=1.05, our requirement for the refractive index uniformity in the transverse plane direction of an aerogel tile is |δ(n-1)/(n-1)|<4% in a focusing dual layer radiator (with different refractive indices) scheme. We applied the radiographic technique to evaluate the density uniformity of our original aerogels from a trial production and that of Panasonic products (SP-50) as a reference, and to confirm they have sufficient density uniformity within ±1% along the transverse plane direction. The measurement results show that the proposed technique can quantitatively estimate the density uniformity of aerogels.

  3. Clinical and radiographic maxillofacial features of pycnodysostosis.

    PubMed

    Alves, Nilton; Cantín, Mario

    2014-01-01

    The aim of this study was to review of the literature to determine the radiographic and clinical maxillofacial features of pycnodysostosis emphasizing the main aspects of interest to the dentist in order to make them fit for the proper treatment of this population. It is important to make the diagnosis as early as possible in order to plan the treatment more suitable to provide a better life's quality to the patients. The most frequent clinical maxillofacial features were: grooved palate, midfacial hypoplasia, mandibular hypoplasia and enamel hypoplasia. The most common radiographic maxillofacial features were: obtuse mandibular angle, frontal/parietal/occiptal bossing, open fontanels and sutures, multiple impacted teeth. The earlier diagnostic of pycnodysostosis has a fundamental role in general health of the patients. We consider that is very important that the dentist know recognize the radiographic and clinical maxillofacial features of pycnodysostosis, which allows correct treatment planning avoiding risks and ensuring better life's quality to the patients. PMID:24753741

  4. Magnetic cassette for radiographic film material

    SciTech Connect

    Dallas, D.

    1985-03-26

    A radiographic film cassette having a plurality of magnet components integral with the cassette holder for adhering the cassette to ferrous material in X-raying for defects in welds or fissures in shipyards, pipe lines, or the like. What is provided is a substantially flexible cassette envelope comprising first and second layers of radiographic intensifying screens with a sheet of radiographic film positioned therebetween. The cassette would be a cassette envelope constructed of waterproof fabric or other suitable material providing a light-free environment, and having the ability to flex around the curvature of the surface of a pipe or the like to be x-rayed. There is further provided a plurality of magnet components, preferably situated in each corner of the cassette envelope and flexibly attached thereto for overall adherence of the envelope to the surface of the pipe or the like to be x-rayed during the process.

  5. A radiographic scanning technique for cores

    USGS Publications Warehouse

    Hill, G.W.; Dorsey, M.E.; Woods, J.C.; Miller, R.J.

    1979-01-01

    A radiographic scanning technique (RST) can produce single continuous radiographs of cores or core sections up to 1.5 m long and up to 30 cm wide. Changing a portable industrial X-ray unit from the normal still-shot mode to a scanning mode requires simple, inexpensive, easily constructed, and highly durable equipment. Additional components include a conveyor system, antiscatter cylinder-diaphragm, adjustable sample platform, developing tanks, and a contact printer. Complete cores, half cores, sample slabs or peels may be scanned. Converting the X-ray unit from one mode to another is easy and can be accomplished without the use of special tools. RST provides the investigator with a convenient, continuous, high quality radiograph, saves time and money, and decreases the number of times cores have to be handled. ?? 1979.

  6. [Radiographic assessment of pulmonary hypertension: Methodical aspects].

    PubMed

    Korobkova, I Z; Lazutkina, V K; Nizovtsova, L A; Riden, T V

    2015-01-01

    Pulmonary hypertension is a menacing complication of a number of diseases, which is responsible for high mortality rates and considerably poorer quality of life in a patient. The timely detection for pulmonary hypertension allows timely initiation of treatment, thus improvement in prognosis in the patient. Chest X-ray is the most commonly used radiographic technique for various causes. Physicians' awareness about the radiographic manifestations of pulmonary hypertension may contribute to the earlier detection of this severe disease. Owing to the natural contrast of reflected structures, a chest X-ray film gives a unique opportunity to assess pulmonary circulation vessels, to reveal the signs of pulmonary hypertension, and to estimate trends in the course of the disease. The paper details a procedure for analysis and the normal radiographic anatomy of pulmonary circulation vessels, gives the present classification of pulmonary hypertension, and sets forth its X-ray semiotics. PMID:26552229

  7. Understanding carpal instability: a radiographic perspective.

    PubMed

    Kani, Kimia Khalatbari; Mulcahy, Hyojeong; Chew, Felix S

    2016-08-01

    The wrist is disposed to a variety of instability patterns owing to its complex anatomical and biomechanical properties. Various classification schemes have been proposed to describe the different patterns of carpal instability, of which the Mayo classification is the most commonly used. Understanding the concepts and pertinent terminology of this classification scheme is important for the correct interpretation of images and optimal communication with referring physicians. Standard wrist radiographs are the first line of imaging in carpal instability. Additional information may be obtained with the use of stress radiographs and other imaging modalities. PMID:27085694

  8. Common errors in evaluating chest radiographs.

    PubMed

    Mann, H

    1990-01-01

    Chest radiographs that are correctly obtained and interpreted provide valuable diagnostic information. However, some radiographs are not taken at total lung capacity, and the appearance of the lungs on film may mimic certain lung disorders. Most common interpretive pitfalls in chest radiography can be avoided by physicians who are familiar with the film appearance of varying degrees of lung inflation, technical limitations of portable radiography, and common chest abnormalities. When further definition is necessary, additional projections should be obtained. Chest fluoroscopy and computed tomography can offer further clarification, if needed. PMID:2296566

  9. Unusual ghost image in a panoramic radiograph.

    PubMed

    Venkatraman, Sreenivasan; Gowda, J S; Kamarthi, N

    2011-09-01

    A panoramic radiograph was taken for a 9-year-old female patient with her earrings on; thus, artefactual shadows were cast on the radiograph. In addition to the two real images of the earrings, three additional images were seen corresponding to ghost images of the earrings. They were unusual not only in appearance but also because there were three in number. This paper discusses the cause of such images as it revisits the principles of panoramic radiology with respect to ghost images. PMID:21831982

  10. Unusual ghost image in a panoramic radiograph

    PubMed Central

    Venkatraman, S; Gowda, JS; Kamarthi, N

    2011-01-01

    A panoramic radiograph was taken for a 9-year-old female patient with her earrings on; thus, artefactual shadows were cast on the radiograph. In addition to the two real images of the earrings, three additional images were seen corresponding to ghost images of the earrings. They were unusual not only in appearance but also because there were three in number. This paper discusses the cause of such images as it revisits the principles of panoramic radiology with respect to ghost images. PMID:21831982

  11. Method of radiographic inspection of wooden members

    NASA Technical Reports Server (NTRS)

    Berry, Maggie L. (Inventor); Berry, Robert F., Jr. (Inventor)

    1990-01-01

    The invention is a method to be used for radiographic inspection of a wooden specimen for internal defects which includes the steps of introducing a radiopaque penetrant into any internal defects in the specimen through surface openings; passing a beam of radiation through a portion of the specimen to be inspected; and making a radiographic film image of the radiation passing through the specimen, with the radiopaque penetrant in the specimen absorbing the radiation passing through it, thereby enhancing the resulting image of the internal defects in the specimen.

  12. Radiographic spectrum of rectocolonic calcification from schistosomiasis.

    PubMed

    Fataar, S; Bassiony, H; Hamed, M S; Ghoneim, I; Satyanath, S; Hebbar, H G; Elgindy, N N; Hanna, R M

    1984-05-01

    Rectocolonic calcification was detected radiographically in 17 sites in 14 patients undergoing excretory urography for the assessment of urinary schistosomiasis. The right colon was involved in 11 sites, the rectum in four, and the left colon in two. The pattern of calcification varied according to the degree of bowel distension. A laminar pattern was common to all sites and occurred when the rectum or colon was distended with air, feces, or barium. A laminar or irregular amorphous density was found in the empty colon, whereas the calcified, empty rectum had a corrugated pattern. Rectocolonic calcification is probably the most common radiographic manifestation of schistosomal infestation of the gastrointestinal tract. PMID:6609576

  13. Validation of a new radiographic protocol for Asian elephant feet and description of their radiographic anatomy.

    PubMed

    Mumby, C; Bouts, T; Sambrook, L; Danika, S; Rees, E; Parry, A; Rendle, M; Masters, N; Weller, R

    2013-10-01

    Foot problems are extremely common in elephants and radiography is the only imaging method available but the radiographic anatomy has not been described in detail. The aims of this study were to develop a radiographic protocol for elephant feet using digital radiography, and to describe the normal radiographic anatomy of the Asian elephant front and hind foot. A total of fifteen cadaver foot specimens from captive Asian elephants were radiographed using a range of projections and exposures to determine the best radiographic technique. This was subsequently tested in live elephants in a free-contact setting. The normal radiographic anatomy of the Asian elephant front and hind foot was described with the use of three-dimensional models based on CT reconstructions. The projection angles that were found to be most useful were 65-70° for the front limb and 55-60° in the hind limb. The beam was centred 10-15 cm proximal to the cuticle in the front and 10-15 cm dorsal to the plantar edge of the sole in the hind foot depending on the size of the foot. The protocol developed can be used for larger-scale diagnostic investigations of captive elephant foot disorders, while the normal radiographic anatomy described can improve the diagnostic reliability of elephant feet radiography. PMID:24048633

  14. Development of a dual MCP framing camera for high energy x-rays

    SciTech Connect

    Izumi, N. Hall, G. N.; Carpenter, A. C.; Allen, F. V.; Cruz, J. G.; Felker, B.; Hargrove, D.; Holder, J.; Lumbard, A.; Montesanti, R.; Palmer, N. E.; Piston, K.; Stone, G.; Thao, M.; Vern, R.; Zacharias, R.; Landen, O. L.; Tommasini, R.; Bradley, D. K.; Bell, P. M.; and others

    2014-11-15

    Recently developed diagnostic techniques at LLNL require recording backlit images of extremely dense imploded plasmas using hard x-rays, and demand the detector to be sensitive to photons with energies higher than 50 keV [R. Tommasini et al., Phys. Phys. Plasmas 18, 056309 (2011); G. N. Hall et al., “AXIS: An instrument for imaging Compton radiographs using ARC on the NIF,” Rev. Sci. Instrum. (these proceedings)]. To increase the sensitivity in the high energy region, we propose to use a combination of two MCPs. The first MCP is operated in a low gain regime and works as a thick photocathode, and the second MCP works as a high gain electron multiplier. We tested the concept of this dual MCP configuration and succeeded in obtaining a detective quantum efficiency of 4.5% for 59 keV x-rays, 3 times larger than with a single plate of the thickness typically used in NIF framing cameras.

  15. An Innovative Method of Assessing the Mechanical Axis Deviation in the Lower Limb in Standing Position

    PubMed Central

    Kamath, Jagannath; Jayasheelan, Nikil; Singh, Rohit

    2016-01-01

    Introduction Various methods of measuring mechanical axis deviation of lower limb have been described including radiographic and CT scanogram, intraoperative fluoroscopy with the use of an electrocautery cord. These methods determine the mechanical axis in a supine, non-weight bearing position. Although long cassette standing radiographic view is used for the purpose but is not available at most centres. A dynamic method of determining the mechanical axis in a weight bearing position was devised in this study. Aim The aim of the study was to describe a simpler and newer method in quantifying the mechanical axis deviation in places where full length cassettes for standing X rays are not available. Materials and Methods A pilot study was conducted on 15 patients. The deviation from the mechanical axis was measured using a manually operated, hydraulic mechanism based, elevating scissor lift table. Patient was asked to stand erect over the elevating lift table with both patellae facing forward and C-arm image intensifier was positioned horizontally. Radiological markers were tied to a radio-opaque thread and placed at the centre of head of the femur and another at the centre of the tibio-talar joint. C-arm views of the hip, ankle and knee joint were taken to confirm the correct position of the marker by varying the height of the lift table. Results The mechanical axis deviation values were recorded by measuring distance between the centre of the knee and radio-opaque thread in cm. This was measured in each case both clinically and from the image on the monitor. The two values were found to be statistically same. Pain was measured on VAS. Mechanical axis deviation values and VAS score were found to be positively significantly correlated. Conclusion This technique is dynamic, unique and accurate as compared to other methods for assessing mechanical axis deviation in a weight bearing position. PMID:27504362

  16. Lateral cephalometric radiograph versus lateral nasopharyngeal radiograph for quantitative evaluation of nasopharyngeal airway space

    PubMed Central

    Pereira, Suelen Cristina da Costa; Beltrão, Rejane Targino Soares; Janson, Guilherme; Garib, Daniela Gamba

    2014-01-01

    Objective This study compared lateral radiographs of the nasopharynx (LN) and lateral cephalometric radiographs (LC) used to assess nasopharyngeal airway space in children. Material and Methods One examiner measured the nasopharyngeal space of 15 oral breathing patients aged between 5 and 11 years old by using LN and LC. Both assessments were made twice with a 15-day interval in between. Intergroup comparison was performed with t-tests (P < 0.05). Results Comparison between LN and LC measurements showed no significant differences. Conclusion Lateral cephalometric radiograph is an acceptable method used to assess nasopharyngeal airway space. PMID:25279526

  17. Age estimation using intraoral periapical radiographs

    PubMed Central

    Rajpal, Pooja S.; Krishnamurthy, Vasavi; Pagare, Sandeep S.; Sachdev, Geeta D.

    2016-01-01

    Context: Changes in the size of dental pulp caused by the apposition of secondary dentin and occlusal wear are morphometric parameters for estimating age. Aim: To estimate the accuracy of age evaluation by Kvaal's method and the effect of occlusal wear on age using digital intraoral periapical radiographs in a subset of the Indian population. Materials and Methods: A total of 300 teeth were radiographically evaluated using intraoral periapical digital radiographs from 50 adult patients. A few modifications were made in the design of the study compared to the original Kvaal's method. The radiographs of three teeth from each jaw were taken and morphometric measurements in ratios were analyzed, which included the pulp length to tooth length (X1), pulp length to root length (X2), pulp width to root widths at three defined levels (X3), and tooth length to root length (X4). Statistical Analysis: The Pearson product-moment correlation coefficient (PCC) between age and the morphological variables showed that among them X1, X2, and X3 were statistically significant but not the tooth root length ratio (X4). Conclusions: The ratios X1, X2, and X3 were good indicators of age and hence a multiple linear regression model for age estimation was derived using these three variables. However, it was found that X4 was not a good indicator of age estimation in said population. PMID:27051226

  18. Radiographic applications of spatial frequency multiplexing

    NASA Technical Reports Server (NTRS)

    Macovski, A.

    1981-01-01

    The application of spacial frequency encoding techniques which allow different regions of the X-ray spectrum to be encoded on conventional radiographs was studied. Clinical considerations were reviewed, as were experimental studies involving the encoding and decoding of X-ray images at different energies and the subsequent processing of the data to produce images of specific materials in the body.

  19. Extraoral radiographic technique: an alternative approach.

    PubMed

    Newman, Michael E; Friedman, Seymour

    2003-06-01

    The inability of certain patient populations to accept intraoral films and/or sensors can cause complications in the performance of endodontic therapy. An alternative technique (extraoral film placement) can be used to obtain clinically diagnostic radiographs. This article describes the alternative technique. PMID:12814229

  20. Digital radiographic systems detect boiler tube cracks

    SciTech Connect

    Walker, S.

    2008-06-15

    Boiler water wall leaks have been a major cause of steam plant forced outages. But conventional nondestructive evaluation techniques have a poor track record of detecting corrosion fatigue cracking on the inside surface of the cold side of waterwall tubing. EPRI is performing field trials of a prototype direct-digital radiographic system that promises to be a game changer. 8 figs.

  1. TECHNICAL TRAINING FOR INDUSTRIAL RADIOGRAPHERS. FINAL REPORT.

    ERIC Educational Resources Information Center

    BEARDEN, H.D.

    TO OFFSET THE PROBLEM OF A SHORTAGE OF QUALIFIED TECHNICIANS TO SERVE AS RADIOGRAPHERS IN INDUSTRY, 19 STUDENTS WERE TRAINED IN TWO CLASSES, THE FIRST CONSISTING OF 19, AND THE SECOND OF EIGHTEEN 30-HOUR WEEKS. ORGANIZED FORMAL OR LECTURE-TYPE INSTRUCTION WAS PRESENTED IN SOME SUBJECT AREAS, BUT THE MAJOR EMPHASIS WAS ON LABORATORY EXPERIENCES…

  2. Survey of Radiographic Requirements and Techniques.

    ERIC Educational Resources Information Center

    Farman, Allan G.; Shawkat, Abdul H.

    1981-01-01

    A survey of dental schools revealed little standardization of student requirements for dental radiography in the United States. There was a high degree of variability as to what constituted a full radiographic survey, which has implications concerning the maximum limits to patient exposure to radiation. (Author/MLW)

  3. Pitfalls in Radiographic Interpretation of Emphysema Patients.

    PubMed

    Baik, Jun Hyun; Ko, Jeong Min; Park, Hyun Jin

    2016-08-01

    Emphysema commonly accompanies various complications such as pneumonia. Sometimes, these comorbidities look so strange on images, because destroyed airspaces could change the usual disease progression. So, we demonstrated various cases of common comorbidities with unusual radiographic findings in emphysema patients. Awareness of various findings of emphysema with commonly coexistent diseases may aid in the proper diagnosis and management of emphysema patients. PMID:27147485

  4. The Immediate Post-Operative Radiograph is an Unreliable Measure of Coronal Plane Alignment in Total Knee Replacement

    PubMed Central

    Petterwood, Joshua; Dowsey, Michelle M.; Rodda, Daevyd; Choong, Peter F. M.

    2014-01-01

    Background: Restoration of a neutral mechanical axis is a primary goal of total knee replacement (TKR). A mechanical axis within 3° of neutral has been correlated with improved implant longevity, function, and patient satisfaction. We hypothesize that the immediate post-operative radiograph is an unreliable method of measuring alignment following TKR surgery. Methods: Seventy-five consecutive patients had supine X-rays performed on day two post-operatively followed by standing long-leg radiographs (LLRs) 6 weeks post-operatively. Correlation was sought between the mechanical axis measured on the LLR and surrogate markers of alignment on the post-operative X-ray including component alignment and an estimation of anatomical alignment using the available length of femoral and tibial shafts. Inter- and intra-observer reliabilities were assessed. Results: The mean mechanical axis on the LLR was 180.5 (SD 3.0, range 175.1–187.1). Mean offset between anatomical axis and mechanical axis was 6.4°. The mean anatomical axis measured on the short-leg X-ray was 174.9 (SD 2.4, range 169.5–181.3). Mechanical axis on the LLR was compared to the anatomical axis measured on the short-leg radiograph (SLR) + 6° with an interclass correlation coefficient of 0.588 (p < 0.001). The level of disagreement between the short- and long-leg X-rays was assessed using the Bland–Altman method and demonstrated clinically important discrepancies of 5 or more degrees in 9% of cases. Inter- and intra-observer agreements were high on all measures (p < 0.001). Conclusion: The long-leg weight bearing X-ray is an essential tool to accurately assess coronal plane alignment post TKR. While the immediate post-operative X-ray taken supine provides useful information to the surgeon on any immediate complications, our results indicate that it cannot be relied upon to determine correct restoration of the mechanical axis. PMID:25593959

  5. Reliability of Panoramic Radiographs in the Localization of Mandibular Foramen

    PubMed Central

    Patil, Karthikeya; Guledgud, Mahima V

    2015-01-01

    Objective The present study evaluated the reliability and accuracy of panoramic radiographs in the localization of mandibular foramen. Materials and Methods Twenty five Indian dry human adult mandibles constituted the study material. Ten measurements were carried on each of them to evaluate the location of mandibular foramen with respect to adjacent anatomic landmarks. Panoramic radiographs were then made of the mandibles. Same distances were measured on the traced images of the radiographs. Paired t-test and Pearson’s correlation test were applied to evaluate the accuracy and reliability of panoramic radiographs in localization of mandibular foramen. Results The mean distances measured on dry mandibles and panoramic radiographs showed statistically significant difference (p<0.05). There was strong positive correlation between the measurements on dry mandible and panoramic radiographs. Conclusion The panoramic radiographs can serve as a guide in locating the anterosuperior point of mandibular foramen on panoramic radiographs. PMID:26155559

  6. Radiographic measurement of bowleg deformity: variability due to method and limb rotation.

    PubMed

    Stricker, S J; Faustgen, J P

    1994-01-01

    In evaluation of bowlegs, the tibiofemoral axis (TFA) and the proximal tibial metaphyseal-diaphyseal angle (MDA) are commonly measured, but both are subject to measurement error. In this study, we determined the intraobserver errors for the MDA and TFA, comparing several different measurement techniques. We also determined the variability of these angles caused by 15 degrees and 30 degrees of external rotation of the knee. We noted that limb malrotation may affect the measurement variability of these angles significantly, especially the TFA. To minimize radiographic measurement error, the clinician must ensure neutral limb rotation and uniform measurement technique. PMID:8188824

  7. Broadband Venetian Blind polarizer with dual vanes

    NASA Technical Reports Server (NTRS)

    Conroy, Bruce L.; Hoppe, Daniel J.; Imbriale, William A.

    1993-01-01

    During development of a Venetian Blind polarizer, high reflections and substantial pattern deformation were noted. Analysis showed that when the polarizer was illuminated slightly off axis, a degenerate mode was excited. This mode is resonant at the design center frequency, and was the cause of the problems. A design developed using dual vanes has been shown to be free of the problem. It also has greater bandwidth.

  8. Broadband Venetian Blind polarizer with dual vanes

    NASA Astrophysics Data System (ADS)

    Conroy, Bruce L.; Hoppe, Daniel J.; Imbriale, William A.

    1993-05-01

    During development of a Venetian Blind polarizer, high reflections and substantial pattern deformation were noted. Analysis showed that when the polarizer was illuminated slightly off axis, a degenerate mode was excited. This mode is resonant at the design center frequency, and was the cause of the problems. A design developed using dual vanes has been shown to be free of the problem. It also has greater bandwidth.

  9. What is the real angle of deviation of metacarpal neck fractures on oblique views? A radiographic study☆

    PubMed Central

    de Góes Ribeiro, Arthur; Gonçalez, Daniel Hidalgo; Filho, João Manoel Fonseca; da Fonseca, Guilherme Marques; Costa, Antonio Carlos; Chakkour, Ivan

    2016-01-01

    Objective The aim of this study was to establish an indirect, easy-to-use, predictable and safe means of obtaining the true degree of displacement of fractures of the neck of the fifth metacarpal bone, through oblique radiographic views. Methods An anatomical specimen from the fifth human metacarpal was dissected and subjected to ostectomy in the neck region. A 1-mm Kirschner wire was fixed to the base of the fifth metacarpal bone, perpendicular to the longitudinal axis of the bone and parallel to the ground. Another six Kirschner wires of the same diameter were bent over and attached to the ostectomized bone to simulate fracture displacement. Axial rotation of the metacarpus was used to create oblique radiographic views. Radiographic images were generated with different angles and at several degrees of rotation of the bone. Results We deduced a mathematical formula that showed the true displacement of fractures of the neck of the fifth metacarpal bone by means of oblique radiographs. Conclusions Oblique radiographs at 30̊ of supination provided the best view of the bone and least variation from the real value of the displacement of fractures of the fifth metacarpal bone. The mathematical formula deduced was concordant with the experimental model used. PMID:27069882

  10. 21 CFR 892.1970 - Radiographic ECG/respirator synchronizer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Radiographic ECG/respirator synchronizer. 892.1970... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1970 Radiographic ECG/respirator synchronizer. (a) Identification. A radiographic ECG/respirator synchronizer is a device intended to be used...