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Sample records for axis radiographic hydrodynamic

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. Radiographic determinants of the elbow rotation axis: experimental identification and quantitative validation.

    PubMed

    Bottlang, M; O'Rourke, M R; Madey, S M; Steyers, C M; Marsh, J L; Brown, T D

    2000-09-01

    This study identifies new radiographic indices to approximate the location of the elbow rotational axis. With use of electromagnetic motion tracking source data, the average rotational axis of the ulnohumeral articulation was calculated in seven cadaveric specimens. Quasi-lateral radiographs of the elbow specimens were then analyzed to identify radiographic landmarks of the elbow axis in the lateral view. The spatial relationships of these landmarks with the elbow aligned on-axis were contrasted with their relationships in eight distinct off-axis alignments. Elbow axis orientation in the transverse plane (internal/external rotation) was identified by the location of a dense intramedullary cortical line, appearing in the projection of the distal humerus in relation to the periosteal surface of the posterior cortex of the humerus. This intramedullary line corresponds to the posteromedial cortex of the distal humerus. Correct alignment occurred when this line laid 27.1+/-3.7% of the anteroposterior humeral diameter anterior from the periosteal surface of the posterior cortex. Axis orientation in the coronal plane (abduction/adduction) was identified by the concentric appearance of radiographic arcs formed by the capitellum, trochlear sulcus, and medial trochlear flange. Using these radiographic indices, three orthopaedic surgeons were able to fluoroscopically align the elbow along the axis of rotation with an accuracy of 3.7+/-1.8 degrees. These results are immediately applicable to fluoroscopic identification of the elbow axis. This technique can be used to increase the accuracy of hinge placement during application of hinged external fixation or distraction arthroplasty.

  9. The Mechanical Axis of the First Ray: A Radiographic Assessment in Hallux Abducto Valgus Evaluation.

    PubMed

    LaPorta, Guido A; Nasser, Ellianne M; Mulhern, Jennifer L; Malay, D Scot

    2016-01-01

    The present report describes a new method of hallux abducto valgus deformity correction planning using the mechanical axis of the medial column (mechanical axis planning). This method of radiographic evaluation identifies an ideal position for the first metatarsal after correction and is useful regardless of the surgical procedure chosen. We retrospectively reviewed 200 radiographs to identify a "normal" value for the mechanical axis angle. We reviewed 100 radiographs of patients with hallux abducto valgus deformity (deformity group) and 100 radiographs of patients without hallux abducto valgus deformity (control group). The deformity group revealed an M1-M2 anatomic axis angle of 13.5° ± 2.83° and an M1-M2 mechanical axis angle of 11.58° ± 1°. The control group revealed an M1-M2 anatomic axis angle of 7.5° ± 1.76° and an M1-M2 mechanical axis angle of 11.19° ± 0.9°. The differences in the M1-M2 anatomic axis angle and M1-M2 mechanical axis angle were statistically significant between the control and deformity groups. We sought to provide a reliable method for planning hallux abducto valgus deformity correction by aligning the mechanical axis of the medial column and the mechanical axis of the first ray to the "normal" value of 11° to reduce the deformity.

  10. Inductive voltage adder advanced hydrodynamic radiographic technology demonstration

    SciTech Connect

    Mazarakis, M.G.; Poukey, J.W.; Maenchen; Rovang, D.C.

    1997-04-01

    This paper presents the design, results, and analysis of a high-brightness electron beam technology demonstration experiment completed at Sandia National Laboratories, performed in collaboration with Los Alamos National Laboratory. The anticipated electron beam parameters were: 12 MeV, 35-40 kA, 0.5-mm rms radius, and 40-ns full width half maximum (FWHM) pulse duration. This beam, on an optimum thickness tantalum converter, should produce a very intense x-ray source of {approximately} 1.5-mm spot size and 1 kR dose @ 1 m. The accelerator utilized was SABRE, a pulsed inductive voltage adder, and the electron source was a magnetically immersed foilless electron diode. For these experiments, SABRE was modified to high-impedance negative-polarity operation. A new 100-ohm magnetically insulated transmission line cathode electrode was designed and constructed; the cavities were rotated 180{degrees} poloidally to invert the central electrode polarity to negative; and only one of the two pulse forming lines per cavity was energized. A twenty- to thirty-Tesla solenoidal magnet insulated the diode and contained the beam at its extremely small size. These experiments were designed to demonstrate high electron currents in submillimeter radius beams resulting in a high-brightness high-intensity flash x-ray source for high-resolution thick-object hydrodynamic radiography. The SABRE facility high-impedance performance was less than what was hoped. The modifications resulted in a lower amplitude (9 MV), narrower-than-anticipated triangular voltage pulse, which limited the dose to {approximately} 20% of the expected value. In addition, halo and ion-hose instabilities increased the electron beam spot size to > 1.5 mm. Subsequent, more detailed calculations explain these reduced output parameters. An accelerator designed (versus retrofit) for this purpose would provide the desired voltage and pulse shape.

  11. 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

  12. The beamline for the second axis of the dual axis radiographic hydrodynamic test facility

    SciTech Connect

    Caporaso, G J; Chen, Y J; Fawley, W M; Lee, E P; Paul, A C; Westenkow, G

    1999-03-23

    During normal DARHT II operation, the beam exiting the accelerator will be well characterized by its nominal design parameters of 20-MeV, 2000-Amperes, 2-{micro}sec-pulse length, and 3 cm-mr unnormalized emittance. Normal operation will have the beam delivered to a beam dump via several DC magnets. A 2-way kicker magnet is used to deflect portions of the beam into the straight ahead beamline leading to either a diagnostic beamline or to the converter target beamline. During start up and or beam development periods, the beam exiting the accelerator may have parameters outside the acceptable range of values for normal operation. The Enge beamline must accommodate this range of unacceptable beam parameters, delivering the entire 80 KiloJoule of beam to the dump even though the energy, emittance, and/or match is outside the nominal design range.

  13. 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

  14. 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.

  15. 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.

  16. 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…

  17. Research on the unsteady hydrodynamic characteristics of vertical axis tidal turbine

    NASA Astrophysics Data System (ADS)

    Zhang, Xue-wei; Zhang, Liang; Wang, Feng; Zhao, Dong-ya; Pang, Cheng-yan

    2014-03-01

    The unsteady hydrodynamic characteristics of vertical axis tidal turbine are investigated by numerical simulation based on viscous CFD method. The starting mechanism of the turbine is revealed through analyzing the interaction of its motion and dynamics during starting process. The operating hydrodynamic characteristics of the turbine in wave-current condition are also explored by combining with the linear wave theory. According to possible magnification of the cyclic loads in the maximum power tracking control of vertical axis turbine, a novel torque control strategy is put forward, which can improve the structural characteristics significantly without effecting energy efficiency.

  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. 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

  20. 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.

  1. 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

  2. AWE multi-axis radiographic facility: A review of 3D-reconstructions from limited data

    NASA Astrophysics Data System (ADS)

    Pang, T. F.

    2001-05-01

    This paper presents a 3D-reconstruction study carried out to address issues regarding the optimal number of radiographic views and their orientations in a new flash X-radiography facility. The results presented in this paper are taken from reconstructions with noiseless projection data simulated from a phantom. These idealized results have shown the relative improvements gained by adding additional views, as well as the impact of varying the view orientations and the effectiveness of various constraints to suppress reconstruction artefacts. It has been concluded that, given sufficient a priori knowledge to implement appropriate constraints, a limited number of views (as few as five in the new facility) can give reasonable reconstructions, and that the reconstruction is relatively insensitive to the view orientation. .

  3. Attenuation and image noise level based online z-axis tube current modulation for CT scans independent with localizer radiograph: simulation study and results

    NASA Astrophysics Data System (ADS)

    Tian, Yi; Chen, Mahao; Kong, Jun

    2009-02-01

    With the online z-axis tube current modulation (OZTCM) technique proposed by this work, full automatic exposure control (AEC) for CT systems could be realized with online feedback not only for angular tube current modulation (TCM) but also for z-axis TCM either. Then the localizer radiograph was not required for TCM any more. OZTCM could be implemented with 2 schemes as attenuation based μ-OZTCM and image noise level based μ-OZTCM. Respectively the maximum attenuation of projection readings and standard deviation of reconstructed images can be used to modulate the tube current level in z-axis adaptively for each half (180 degree) or full (360 degree) rotation. Simulation results showed that OZTCM achieved better noise level than constant tube current scan case by using same total dose in mAs. The OZTCM can provide optimized base tube current level for angular TCM to realize an effective auto exposure control when localizer radiograph is not available or need to be skipped for simplified scan protocol in case of emergency procedure or children scan, etc.

  4. Experimental study on hydrodynamic characteristics of vertical-axis floating tidal current energy power generation device

    NASA Astrophysics Data System (ADS)

    Ma, Yong; Li, Teng-fei; Zhang, Liang; Sheng, Qi-hu; Zhang, Xue-wei; Jiang, Jin

    2016-10-01

    To study the characteristics of attenuation, hydrostatic towage and wave response of the vertical-axis floating tidal current energy power generation device (VAFTCEPGD), a prototype is designed and experiment is carried out in the towing tank. Free decay is conducted to obtain attenuation characteristics of the VAFTCEPGD, and characteristics of mooring forces and motion response, floating condition, especially the lateral displacement of the VAFTCEPGD are obtained from the towing in still water. Tension response of the #1 mooring line and vibration characteristics of the VAFTCEPGD in regular waves as well as in level 4 irregular wave sea state with the current velocity of 0.6 m/s. The results can be reference for theoretical study and engineering applications related to VAFTCEPGD.

  5. 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.

  6. Annual Report: Hydrodynamics and Radiative Hydrodynamics with Astrophysical Applications

    SciTech Connect

    R. Paul Drake

    2005-12-01

    We report the ongoing work of our group in hydrodynamics and radiative hydrodynamics with astrophysical applications. During the period of the existing grant, we have carried out two types of experiments at the Omega laser. One set of experiments has studied radiatively collapsing shocks, obtaining high-quality scaling data using a backlit pinhole and obtaining the first (ever, anywhere) Thomson-scattering data from a radiative shock. Other experiments have studied the deeply nonlinear development of the Rayleigh-Taylor (RT) instability from complex initial conditions, obtaining the first (ever, anywhere) dual-axis radiographic data using backlit pinholes and ungated detectors. All these experiments have applications to astrophysics, discussed in the corresponding papers either in print or in preparation. We also have obtained preliminary radiographs of experimental targets using our x-ray source. The targets for the experiments have been assembled at Michigan, where we also prepare many of the simple components. The above activities, in addition to a variety of data analysis and design projects, provide good experience for graduate and undergraduates students. In the process of doing this research we have built a research group that uses such work to train junior scientists.

  7. 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.

  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. Annual Report 2006 for Hydrodynamics and Radiation Hydrodynamics with Astrophysical Applications

    SciTech Connect

    R. Paul Drake

    2007-04-05

    We report the ongoing work of our group in hydrodynamics and radiation hydrodynamics with astrophysical applications. During the period of the existing grant, we have carried out two types of experiments at the Omega laser. One set of experiments has studied radiatively collapsing shocks, obtaining data using a backlit pinhole with a 100 ps backlighter and beginning to develop the ability to look into the shock tube with optical or x-ray diagnostics. Other experiments have studied the deeply nonlinear development of the Rayleigh-Taylor (RT) instability from complex initial conditions, using dual-axis radiographic data with backlit pinholes and ungated detectors to complete the data set for a Ph.D. student. We lead a team that is developing a proposal for experiments at the National Ignition Facility and are involved in experiments at NIKE and LIL. All these experiments have applications to astrophysics, discussed in the corresponding papers. We assemble the targets for the experiments at Michigan, where we also prepare many of the simple components. We also have several projects underway in our laboratory involving our x-ray source. The above activities, in addition to a variety of data analysis and design projects, provide good experience for graduate and undergraduates students. In the process of doing this research we have built a research group that uses such work to train junior scientists.

  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. 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

  12. 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.

  13. Ship Hydrodynamics

    ERIC Educational Resources Information Center

    Lafrance, Pierre

    1978-01-01

    Explores in a non-mathematical treatment some of the hydrodynamical phenomena and forces that affect the operation of ships, especially at high speeds. Discusses the major components of ship resistance such as the different types of drags and ways to reduce them and how to apply those principles for the hovercraft. (GA)

  14. Recent development of hydrodynamic modeling

    NASA Astrophysics Data System (ADS)

    Hirano, Tetsufumi

    2014-09-01

    In this talk, I give an overview of recent development in hydrodynamic modeling of high-energy nuclear collisions. First, I briefly discuss about current situation of hydrodynamic modeling by showing results from the integrated dynamical approach in which Monte-Carlo calculation of initial conditions, quark-gluon fluid dynamics and hadronic cascading are combined. In particular, I focus on rescattering effects of strange hadrons on final observables. Next I highlight three topics in recent development in hydrodynamic modeling. These include (1) medium response to jet propagation in di-jet asymmetric events, (2) causal hydrodynamic fluctuation and its application to Bjorken expansion and (3) chiral magnetic wave from anomalous hydrodynamic simulations. (1) Recent CMS data suggest the existence of QGP response to propagation of jets. To investigate this phenomenon, we solve hydrodynamic equations with source term which exhibits deposition of energy and momentum from jets. We find a large number of low momentum particles are emitted at large angle from jet axis. This gives a novel interpretation of the CMS data. (2) It has been claimed that a matter created even in p-p/p-A collisions may behave like a fluid. However, fluctuation effects would be important in such a small system. We formulate relativistic fluctuating hydrodynamics and apply it to Bjorken expansion. We found the final multiplicity fluctuates around the mean value even if initial condition is fixed. This effect is relatively important in peripheral A-A collisions and p-p/p-A collisions. (3) Anomalous transport of the quark-gluon fluid is predicted when extremely high magnetic field is applied. We investigate this possibility by solving anomalous hydrodynamic equations. We found the difference of the elliptic flow parameter between positive and negative particles appears due to the chiral magnetic wave. Finally, I provide some personal perspective of hydrodynamic modeling of high energy nuclear collisions

  15. 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.

  16. Radiation Hydrodynamics

    SciTech Connect

    Castor, J I

    2003-10-16

    The discipline of radiation hydrodynamics is the branch of hydrodynamics in which the moving fluid absorbs and emits electromagnetic radiation, and in so doing modifies its dynamical behavior. That is, the net gain or loss of energy by parcels of the fluid material through absorption or emission of radiation are sufficient to change the pressure of the material, and therefore change its motion; alternatively, the net momentum exchange between radiation and matter may alter the motion of the matter directly. Ignoring the radiation contributions to energy and momentum will give a wrong prediction of the hydrodynamic motion when the correct description is radiation hydrodynamics. Of course, there are circumstances when a large quantity of radiation is present, yet can be ignored without causing the model to be in error. This happens when radiation from an exterior source streams through the problem, but the latter is so transparent that the energy and momentum coupling is negligible. Everything we say about radiation hydrodynamics applies equally well to neutrinos and photons (apart from the Einstein relations, specific to bosons), but in almost every area of astrophysics neutrino hydrodynamics is ignored, simply because the systems are exceedingly transparent to neutrinos, even though the energy flux in neutrinos may be substantial. Another place where we can do ''radiation hydrodynamics'' without using any sophisticated theory is deep within stars or other bodies, where the material is so opaque to the radiation that the mean free path of photons is entirely negligible compared with the size of the system, the distance over which any fluid quantity varies, and so on. In this case we can suppose that the radiation is in equilibrium with the matter locally, and its energy, pressure and momentum can be lumped in with those of the rest of the fluid. That is, it is no more necessary to distinguish photons from atoms, nuclei and electrons, than it is to distinguish

  17. 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 ...

  18. Bacterial Hydrodynamics

    NASA Astrophysics Data System (ADS)

    Lauga, Eric

    2016-01-01

    Bacteria predate plants and animals by billions of years. Today, they are the world's smallest cells, yet they represent the bulk of the world's biomass and the main reservoir of nutrients for higher organisms. Most bacteria can move on their own, and the majority of motile bacteria are able to swim in viscous fluids using slender helical appendages called flagella. Low-Reynolds number hydrodynamics is at the heart of the ability of flagella to generate propulsion at the micrometer scale. In fact, fluid dynamic forces impact many aspects of bacteriology, ranging from the ability of cells to reorient and search their surroundings to their interactions within mechanically and chemically complex environments. Using hydrodynamics as an organizing framework, I review the biomechanics of bacterial motility and look ahead to future challenges.

  19. 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.

  20. Synchronization and hydrodynamic interactions

    NASA Astrophysics Data System (ADS)

    Powers, Thomas; Qian, Bian; Breuer, Kenneth

    2008-03-01

    Cilia and flagella commonly beat in a coordinated manner. Examples include the flagella that Volvox colonies use to move, the cilia that sweep foreign particles up out of the human airway, and the nodal cilia that set up the flow that determines the left-right axis in developing vertebrate embryos. In this talk we present an experimental study of how hydrodynamic interactions can lead to coordination in a simple idealized system: two nearby paddles driven with fixed torques in a highly viscous fluid. The paddles attain a synchronized state in which they rotate together with a phase difference of 90 degrees. We discuss how synchronization depends on system parameters and present numerical calculations using the method of regularized stokeslets.

  1. 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.

  2. Supernova hydrodynamics

    NASA Astrophysics Data System (ADS)

    Colgate, S. A.

    1981-11-01

    The physics as well as astrophysics of the supernova (SN) phenomenon are illustrated with the appropriate numbers. The explosion of a star, a supernova, occurs at the end of its evolution when the nuclear fuel in its core is almost, or completely, consumed. The star may explode due to a small residual thermonuclear detonation, type I SN, or it may collapse, type I and type II SN, leaving a neutron star remnant. The type I progenitor is thought to be an old accreting white dwarf, 1.4 interior mass, with a close companion star. A type II SN is thought to be a massive young star, 6 to 10 interior mass. The mechanism of explosion is still a challenge to model, being the most extreme conditions of matter and hydrodynamics that occur presently and excessively in the universe.

  3. DARHT Radiographic Grid Scale Correction

    SciTech Connect

    Warthen, Barry J.

    2015-02-13

    Recently it became apparent that the radiographic grid which has been used to calibrate the dimensional scale of DARHT radiographs was not centered at the location where the objects have been centered. This offset produced an error of 0.188% in the dimensional scaling of the radiographic images processed using the assumption that the grid and objects had the same center. This paper will show the derivation of the scaling correction, explain how new radiographs are being processed to account for the difference in location, and provide the details of how to correct radiographic image processed with the erroneous scale factor.

  4. 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.

  5. 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

  6. 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.

  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. 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.

  9. 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.

  10. 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.

  11. Radiographic testing at Lawrence Livermore National Laboratory

    SciTech Connect

    Bossi, R.H.

    1982-04-21

    Radiographic testing is a nondestructive inspection technique which uses penetrating radiation. The Nondestructive Evaluation (NDE) Section at Lawrence Livermore National Laboratory has a broad spectrum of equipment and techniques for radiographic testing. These resources include low-energy vacuum systems, low- and mid-energy cabinet and cell radiographic systems, high-energy linear accelerators, portable x-ray machines and radioisotopes for radiographic inspections. For diagnostic testing the NDE Section also has real-time and flash radiographic equipment.

  12. Vertical axis wind turbine

    SciTech Connect

    Kato, Y.; Seki, K.; Shimizu, Y.

    1981-01-27

    Wind turbines are largely divided into vertical axis wind turbines and propeller (Horizontal axis) wind turbines. The present invention discloses a vertical axis high speed wind turbine provided with a starting and braking control system. This vertical axis wind turbine is formed by having blades of a proper airfoil fitted to respective supporting arms provided radially from a vertical rotary axis by keeping the blade span-wise direction in parallel with the axis and being provided with a low speed control windmill in which the radial position of each operating piece varies with a centrifugal force produced by the rotation of the vertical rotary axis.

  13. 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

  14. Motion blur detection in radiographs

    NASA Astrophysics Data System (ADS)

    Luo, Hui; Sehnert, William J.; Ellinwood, Jacquelyn S.; Foos, David; Reiner, Bruce; Siegel, Eliot

    2008-03-01

    Image blur introduced by patient motion is one of the most frequently cited reasons for image rejection in radiographic diagnostic imaging. The goal of the present work is to provide an automated method for the detection of anatomical motion blur in digital radiographic images to help improve image quality and facilitate workflow in the radiology department. To achieve this goal, the method first reorients the image to a predetermined hanging protocol. Then it locates the primary anatomy in the radiograph and extracts the most indicative region for motion blur, i.e., the region of interest (ROI). The third step computes a set of motion-sensitive features from the extracted ROI. Finally, the extracted features are evaluated by using a classifier that has been trained to detect motion blur. Preliminary experiments show promising results with 86% detection sensitivity, 72% specificity, and an overall accuracy of 76%.

  15. 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.

  16. Vertical axis windmill

    SciTech Connect

    Zheug, Y.K.

    1984-03-06

    A vertical axis windmill has a blade pivotally connected to a rotatable support structure on an axis passing through its center of gravity which is arranged to lie forward of its aerodynamic center whereby the blade automatically swings outwardly and inwardly when moving on the windward and leeward sides respectively of the axis of rotation of said support means.

  17. Hydrodynamic Mass of Bluff Bodies with a Cavity

    NASA Astrophysics Data System (ADS)

    Elgabaili, Mohamed; Desabrais, Kenneth; Johari, Hamid

    2012-11-01

    Hydrodynamic mass of an object may be used to compute the contribution of unsteady drag resulting from potential flow. Even though the hydrodynamic mass of certain bluff bodies such as cylinder and sphere have been available from analytical considerations for a long time, there are no analytical solutions for a general bluff body with a cavity such as a cup facing the flow or a round parachute canopy. There is, however, an analytical solution for spherical shells of various concavities. The translational hydrodynamic mass of cups having various depth and thickness as well as round parachute canopies during inflation was computed using a finite element solver. The kinetic energy of the potential flow around the body was used to extract the hydrodynamic mass. Results indicate that the hydrodynamic mass of a cup can be decomposed into two components, the hydrodynamic mass of a cylinder whose axis is aligned with the flow and the mass of fluid within the cup cavity. Similarly, the hydrodynamic mass of a parachute canopy during various stages of inflation may be written as the hydrodynamic mass of a disk having the same area as the projected area of the canopy plus the mass of fluid enclosed by the canopy. Sponsored by the US Army Natick RDEC.

  18. 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.

  19. 21 CFR 892.1840 - Radiographic film.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 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 both... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Radiographic film. 892.1840 Section 892.1840...

  20. 21 CFR 892.1840 - Radiographic film.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 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 both... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Radiographic film. 892.1840 Section 892.1840...

  1. 21 CFR 892.1840 - Radiographic film.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 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 both... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Radiographic film. 892.1840 Section 892.1840...

  2. 21 CFR 892.1840 - Radiographic film.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 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 both... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Radiographic film. 892.1840 Section 892.1840...

  3. 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... 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...

  4. 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.

  5. Method for converting radiographic images

    SciTech Connect

    Tsuchino, H.; Shimada, F.; Takeuchi, H.; Teshima, M.

    1985-03-26

    In a radiographic image conversion method in which a stimulating light is irradiated to a panel storing a radiation energy in the form of an image to reproduce and then to read out the image, the response speed of a stimulation and the reading speed of a radiographic image area increased by making use of (1) a phosphate type phosphor having the composition, xM/sub 3/(PO/sub 4/)/sub 2/.NX/sub 2/:yA or M/sub 3/(PO/sub 4/)/sub 2/:yA, which is a highly sensitive phosphor capable of readily releasing the stored energy when a stimulating light is irradiated to the phosphor, and (2) the stimulating light having the range of the wavelengths from a visible ray of not shorter that 500 nm to an infrared ray.

  6. HADES, A Radiographic Simulation Code

    SciTech Connect

    Aufderheide, M.B.; Slone, D.M.; Schach von Wittenau, A.E.

    2000-08-18

    We describe features of the HADES radiographic simulation code. We begin with a discussion of why it is useful to simulate transmission radiography. The capabilities of HADES are described, followed by an application of HADES to a dynamic experiment recently performed at the Los Alamos Neutron Science Center. We describe quantitative comparisons between experimental data and HADES simulations using a copper step wedge. We conclude with a short discussion of future work planned for HADES.

  7. Vertical Axis Wind Turbine

    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.

  8. Resurgence in extended hydrodynamics

    NASA Astrophysics Data System (ADS)

    Aniceto, Inês; Spaliński, Michał

    2016-04-01

    It has recently been understood that the hydrodynamic series generated by the Müller-Israel-Stewart theory is divergent and that this large-order behavior is consistent with the theory of resurgence. Furthermore, it was observed that the physical origin of this is the presence of a purely damped nonhydrodynamic mode. It is very interesting to ask whether this picture persists in cases where the spectrum of nonhydrodynamic modes is richer. We take the first step in this direction by considering the simplest hydrodynamic theory which, instead of the purely damped mode, contains a pair of nonhydrodynamic modes of complex conjugate frequencies. This mimics the pattern of black brane quasinormal modes which appear on the gravity side of the AdS/CFT description of N =4 supersymmetric Yang-Mills plasma. We find that the resulting hydrodynamic series is divergent in a way consistent with resurgence and precisely encodes information about the nonhydrodynamic modes of the theory.

  9. Dispersive hydrodynamics: Preface

    NASA Astrophysics Data System (ADS)

    Biondini, G.; El, G. A.; Hoefer, M. A.; Miller, P. D.

    2016-10-01

    This Special Issue on Dispersive Hydrodynamics is dedicated to the memory and work of G.B. Whitham who was one of the pioneers in this field of physical applied mathematics. Some of the papers appearing here are related to work reported on at the workshop "Dispersive Hydrodynamics: The Mathematics of Dispersive Shock Waves and Applications" held in May 2015 at the Banff International Research Station. This Preface provides a broad overview of the field and summaries of the various contributions to the Special Issue, placing them in a unified context.

  10. Synchronization via Hydrodynamic Interactions

    NASA Astrophysics Data System (ADS)

    Kendelbacher, Franziska; Stark, Holger

    2013-12-01

    An object moving in a viscous fluid creates a flow field that influences the motion of neighboring objects. We review examples from nature in the microscopic world where such hydrodynamic interactions synchronize beating or rotating filaments. Bacteria propel themselves using a bundle of rotating helical filaments called flagella which have to be synchronized in phase. Other micro-organisms are covered with a carpet of smaller filaments called cilia on their surfaces. They beat highly synchronized so that metachronal waves propagate along the cell surfaces. We explore both examples with the help of simple model systems and identify generic properties for observing synchronization by hydrodynamic interactions.

  11. Radiographic survey of perlite workers.

    PubMed

    Cooper, W C

    1975-05-01

    Chest roentgenograms of 240 perlite workers employed for 1 to 23 years in the industry, showed no evidence of pneumoconiosis associated with perlite exposures. One individual, found to have simple pneumoconiosis, and one found to have complicated pneumoconiosis, had formerly been diatomaceous earth workers. Since only 28 of the men had been in the industry over 15 years and only seven for 20 years or more, continued surveillance is essential to make sure that there are no effects with more prolonged exposures. Studies of pulmonary function of the individuals who have had relatively long exposures are needed to supplement radiographic evidence.

  12. 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

  13. Skew resisting hydrodynamic seal

    DOEpatents

    Conroy, William T.; Dietle, Lannie L.; Gobeli, Jeffrey D.; Kalsi, Manmohan S.

    2001-01-01

    A novel hydrodynamically lubricated compression type rotary seal that is suitable for lubricant retention and environmental exclusion. Particularly, the seal geometry ensures constraint of a hydrodynamic seal in a manner preventing skew-induced wear and provides adequate room within the seal gland to accommodate thermal expansion. The seal accommodates large as-manufactured variations in the coefficient of thermal expansion of the sealing material, provides a relatively stiff integral spring effect to minimize pressure-induced shuttling of the seal within the gland, and also maintains interfacial contact pressure within the dynamic sealing interface in an optimum range for efficient hydrodynamic lubrication and environment exclusion. The seal geometry also provides for complete support about the circumference of the seal to receive environmental pressure, as compared the interrupted character of seal support set forth in U.S. Pat. Nos. 5,873,576 and 6,036,192 and provides a hydrodynamic seal which is suitable for use with non-Newtonian lubricants.

  14. 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.

  15. 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.

  16. 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.

  17. DIGITAL SPALL RADIOGRAPH ANALYSIS SYSTEM

    SciTech Connect

    CURTIS L. HARRIS - LATA

    1990-01-01

    This report describes progress on work to develop a cost effective, rapid response system for measuring Technology Assessment National Laboratory. momentum and kinetic energy of span for the Advanced Center (ATAC) Armor/Anti-Armor (As) program at Los Alamos The system will exploit data contained in two sets of simultaneous co-planar flash radiographs taken along the center line of anticipated span motion. Data contained in each set (which is proportional to the mass and z-number of the span material intersected by the exposing x-ray at each point) is digitized and used to construct a three dimensional model (called the reconstructed span image) that approximates the original span cloud. From the model the mass of span fragments is computed. The two sets of radiographs, separated in time, represent the span configuration at two instants of time. Span fragments from the first instant are matched with those from the second instant to determine velocity. Evaluation of the fidelity of candidate reconstruction algorithms is the highest priority task in. this development program for the obvious reason that the efficacy of the projected span analysis system depends upon the fidelity of the reconstruction techniques.

  18. 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.

  19. 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

  20. Single-Axis Accelerometer

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis Stephen (Inventor); Capo-Lugo, Pedro A. (Inventor)

    2016-01-01

    A single-axis accelerometer includes a housing defining a sleeve. An object/mass is disposed in the sleeve for sliding movement therein in a direction aligned with the sleeve's longitudinal axis. A first piezoelectric strip, attached to a first side of the object and to the housing, is longitudinally aligned with the sleeve's longitudinal axis. The first piezoelectric strip includes a first strip of a piezoelectric material with carbon nanotubes substantially aligned along a length thereof. A second piezoelectric strip, attached to a second side of the object and to the housing, is longitudinally aligned with the sleeve's longitudinal axis. The second piezoelectric strip includes a second strip of the piezoelectric material with carbon nanotubes substantially aligned along a length thereof. A voltage sensor is electrically coupled to at least one of the first and second piezoelectric strips.

  1. 10 CFR 34.46 - Supervision of radiographers' assistants.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Supervision of radiographers' assistants. 34.46 Section 34... radiographers' assistants. Whenever a radiographer's assistant uses radiographic exposure devices, associated... personal supervision of a radiographer. The personal supervision must include: (a) The...

  2. Hydrodynamics of Turning Flocks.

    PubMed

    Yang, Xingbo; Marchetti, M Cristina

    2015-12-18

    We present a hydrodynamic model of flocking that generalizes the familiar Toner-Tu equations to incorporate turning inertia of well-polarized flocks. The continuum equations controlled by only two dimensionless parameters, orientational inertia and alignment strength, are derived by coarse-graining the inertial spin model recently proposed by Cavagna et al. The interplay between orientational inertia and bend elasticity of the flock yields anisotropic spin waves that mediate the propagation of turning information throughout the flock. The coupling between spin-current density to the local vorticity field through a nonlinear friction gives rise to a hydrodynamic mode with angular-dependent propagation speed at long wavelengths. This mode becomes unstable as a result of the growth of bend and splay deformations augmented by the spin wave, signaling the transition to complex spatiotemporal patterns of continuously turning and swirling flocks.

  3. Hydrodynamics of Turning Flocks.

    PubMed

    Yang, Xingbo; Marchetti, M Cristina

    2015-12-18

    We present a hydrodynamic model of flocking that generalizes the familiar Toner-Tu equations to incorporate turning inertia of well-polarized flocks. The continuum equations controlled by only two dimensionless parameters, orientational inertia and alignment strength, are derived by coarse-graining the inertial spin model recently proposed by Cavagna et al. The interplay between orientational inertia and bend elasticity of the flock yields anisotropic spin waves that mediate the propagation of turning information throughout the flock. The coupling between spin-current density to the local vorticity field through a nonlinear friction gives rise to a hydrodynamic mode with angular-dependent propagation speed at long wavelengths. This mode becomes unstable as a result of the growth of bend and splay deformations augmented by the spin wave, signaling the transition to complex spatiotemporal patterns of continuously turning and swirling flocks. PMID:26722945

  4. 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.

  5. Fluctuations in relativistic causal hydrodynamics

    NASA Astrophysics Data System (ADS)

    Kumar, Avdhesh; Bhatt, Jitesh R.; Mishra, Ananta P.

    2014-05-01

    Formalism to calculate the hydrodynamic fluctuations by applying the Onsager theory to the relativistic Navier-Stokes equation is already known. In this work, we calculate hydrodynamic fluctuations within the framework of the second order hydrodynamics of Müller, Israel and Stewart and its generalization to the third order. We have also calculated the fluctuations for several other causal hydrodynamical equations. We show that the form for the Onsager-coefficients and form of the correlation functions remain the same as those obtained by the relativistic Navier-Stokes equation and do not depend on any specific model of hydrodynamics. Further we numerically investigate evolution of the correlation function using the one dimensional boost-invariant (Bjorken) flow. We compare the correlation functions obtained using the causal hydrodynamics with the correlation function for the relativistic Navier-Stokes equation. We find that the qualitative behavior of the correlation functions remains the same for all the models of the causal hydrodynamics.

  6. 10 CFR 34.23 - Locking of radiographic exposure devices, storage containers and source changers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... surveillance of a radiographer or a radiographer's assistant except at permanent radiographic installations as... containing sealed sources except when under the direct surveillance of a radiographer or a...

  7. Hydrodynamic blade guide

    DOEpatents

    Blaedel, Kenneth L.; Davis, Pete J.; Landram, Charles S.

    2000-01-01

    A saw having a self-pumped hydrodynamic blade guide or bearing for retaining the saw blade in a centered position in the saw kerf (width of cut made by the saw). The hydrodynamic blade guide or bearing utilizes pockets or grooves incorporated into the sides of the blade. The saw kerf in the workpiece provides the guide or bearing stator surface. Both sides of the blade entrain cutting fluid as the blade enters the kerf in the workpiece, and the trapped fluid provides pressure between the blade and the workpiece as an inverse function of the gap between the blade surface and the workpiece surface. If the blade wanders from the center of the kerf, then one gap will increase and one gap will decrease and the consequent pressure difference between the two sides of the blade will cause the blade to re-center itself in the kerf. Saws using the hydrodynamic blade guide or bearing have particular application in slicing slabs from boules of single crystal materials, for example, as well as for cutting other difficult to saw materials such as ceramics, glass, and brittle composite materials.

  8. Hydrodynamics of fossil fishes

    PubMed Central

    Fletcher, Thomas; Altringham, John; Peakall, Jeffrey; Wignall, Paul; Dorrell, Robert

    2014-01-01

    From their earliest origins, fishes have developed a suite of adaptations for locomotion in water, which determine performance and ultimately fitness. Even without data from behaviour, soft tissue and extant relatives, it is possible to infer a wealth of palaeobiological and palaeoecological information. As in extant species, aspects of gross morphology such as streamlining, fin position and tail type are optimized even in the earliest fishes, indicating similar life strategies have been present throughout their evolutionary history. As hydrodynamical studies become more sophisticated, increasingly complex fluid movement can be modelled, including vortex formation and boundary layer control. Drag-reducing riblets ornamenting the scales of fast-moving sharks have been subjected to particularly intense research, but this has not been extended to extinct forms. Riblets are a convergent adaptation seen in many Palaeozoic fishes, and probably served a similar hydrodynamic purpose. Conversely, structures which appear to increase skin friction may act as turbulisors, reducing overall drag while serving a protective function. Here, we examine the diverse adaptions that contribute to drag reduction in modern fishes and review the few attempts to elucidate the hydrodynamics of extinct forms. PMID:24943377

  9. Hydrodynamics of insect spermatozoa

    NASA Astrophysics Data System (ADS)

    Pak, On Shun; Lauga, Eric

    2010-11-01

    Microorganism motility plays important roles in many biological processes including reproduction. Many microorganisms propel themselves by propagating traveling waves along their flagella. Depending on the species, propagation of planar waves (e.g. Ceratium) and helical waves (e.g. Trichomonas) were observed in eukaryotic flagellar motion, and hydrodynamic models for both were proposed in the past. However, the motility of insect spermatozoa remains largely unexplored. An interesting morphological feature of such cells, first observed in Tenebrio molitor and Bacillus rossius, is the double helical deformation pattern along the flagella, which is characterized by the presence of two superimposed helical flagellar waves (one with a large amplitude and low frequency, and the other with a small amplitude and high frequency). Here we present the first hydrodynamic investigation of the locomotion of insect spermatozoa. The swimming kinematics, trajectories and hydrodynamic efficiency of the swimmer are computed based on the prescribed double helical deformation pattern. We then compare our theoretical predictions with experimental measurements, and explore the dependence of the swimming performance on the geometric and dynamical parameters.

  10. Hydrodynamics of fossil fishes.

    PubMed

    Fletcher, Thomas; Altringham, John; Peakall, Jeffrey; Wignall, Paul; Dorrell, Robert

    2014-08-01

    From their earliest origins, fishes have developed a suite of adaptations for locomotion in water, which determine performance and ultimately fitness. Even without data from behaviour, soft tissue and extant relatives, it is possible to infer a wealth of palaeobiological and palaeoecological information. As in extant species, aspects of gross morphology such as streamlining, fin position and tail type are optimized even in the earliest fishes, indicating similar life strategies have been present throughout their evolutionary history. As hydrodynamical studies become more sophisticated, increasingly complex fluid movement can be modelled, including vortex formation and boundary layer control. Drag-reducing riblets ornamenting the scales of fast-moving sharks have been subjected to particularly intense research, but this has not been extended to extinct forms. Riblets are a convergent adaptation seen in many Palaeozoic fishes, and probably served a similar hydrodynamic purpose. Conversely, structures which appear to increase skin friction may act as turbulisors, reducing overall drag while serving a protective function. Here, we examine the diverse adaptions that contribute to drag reduction in modern fishes and review the few attempts to elucidate the hydrodynamics of extinct forms. PMID:24943377

  11. The immature HPO axis.

    PubMed

    Buttram, V C

    1975-01-01

    One cause or anovulation may be an immature hypothalamic-pituitary-ovarian axis. The fact that initial menstrual cycles are usually irregular and often anovulatory implies that a maturation process is taking place in the HPO axis and that cyclic ovulatory menstruation begins only when adequate maturation occurs. Moreover, the external appearance of the ovary of a severely oligomenorrheic or amenorrheic female frequently is similar to that of a prepubertal female--this is, the ovary appears normal in size of slightly smaller, has a smooth, glistening surface without convolutions, and its capsule-like outer surface reveals few, if any, underlying follicles. A reasonable assumption is that there is inadequate gonadotropin stimulation of these ovaries possibly as a result of an immature HPO axis. The studies by radioimmunoassay of FSH and LH levels in prepubertal and pubertal females offer no statistical data by which to measure the maturity of the HPO axis, although consistently low FSH and LH levels may prove meaningful. Studies of FSH and LH in patients exhibiting gonadal dysgenesis neither support or disprove the immature HPO axis theory, but studies of idiopathic sexual precocity tend to support it. Studies using LH-RF in prepubertal and pubertal females indicate a pattern of response which may give useful information in the area.

  12. Hydrodynamic Elastic Magneto Plastic

    1985-02-01

    The HEMP code solves the conservation equations of two-dimensional elastic-plastic flow, in plane x-y coordinates or in cylindrical symmetry around the x-axis. Provisions for calculation of fixed boundaries, free surfaces, pistons, and boundary slide planes have been included, along with other special conditions.

  13. 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.

  14. Hydrodynamic test problems

    SciTech Connect

    Moran, B

    2005-06-02

    We present test problems that can be used to check the hydrodynamic implementation in computer codes designed to model the implosion of a National Ignition Facility (NIF) capsule. The problems are simplified, yet one of them is three-dimensional. It consists of a nearly-spherical incompressible imploding shell subjected to an exponentially decaying pressure on its outer surface. We present a semi-analytic solution for the time-evolution of that shell with arbitrary small three-dimensional perturbations on its inner and outer surfaces. The perturbations on the shell surfaces are intended to model the imperfections that are created during capsule manufacturing.

  15. Radiographic evaluation of the soap man mummy.

    PubMed

    Conlogue, G; Forcier, D; Airo, M; Kilosky, J; Gambardella, S; Mansfield, K; Greenwood, L

    1997-01-01

    This article describes how mobile radiography was used to examine a mummified cadaver exhumed in 1875 and stored in the Smithsonian Museum. Radiographs revealed artifacts imbedded in the cadaver, indicating 1824 as the earliest possible interment. Through radiographic assessment of the skeleton, researchers were able to approximate the individual's age at death. In addition, evidence of pathology, possibly ideopathic skeletal hyperostosis, suggested the individual may have been employed in manual labor. The radiographs, when compared to x-rays of another cadaver exhumed at the same time and place, refuted information in museum records.

  16. 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.

  17. Rapid display of radiographic images

    NASA Astrophysics Data System (ADS)

    Cox, Jerome R., Jr.; Moore, Stephen M.; Whitman, Robert A.; Blaine, G. James; Jost, R. Gilbert; Karlsson, L. M.; Monsees, Thomas L.; Hassen, Gregory L.; David, Timothy C.

    1991-07-01

    The requirements for the rapid display of radiographic images exceed the capabilities of widely available display, computer, and communications technologies. Computed radiography captures data with a resolution of about four megapixels. Large-format displays are available that can present over four megapixels. One megapixel displays are practical for use in combination with large-format displays and in areas where the viewing task does not require primary diagnosis. This paper describes an electronic radiology system that approximates the highest quality systems, but through the use of several interesting techniques allows the possibility of its widespread installation throughout hospitals. The techniques used can be grouped under three major system concepts: a local, high-speed image server, one or more physician's workstations each with one or more high-performance auxiliary displays specialized to the radiology viewing task, and dedicated, high-speed communication links between the server and the displays. This approach is enhanced by the use of a progressive transmission scheme to decrease the latency for viewing four megapixel images. The system includes an image server with storage for over 600 4-megapixel images and a high-speed link. A subsampled megapixel image is fetched from disk and transmitted to the display in about one second followed by the full resolution 4-megapixel image in about 2.5 seconds. Other system components include a megapixel display with a 6-megapixel display memory space and frame-rate update of image roam, zoom, and contrast. Plans for clinical use are presented.

  18. Molecular Hydrodynamics from Memory Kernels.

    PubMed

    Lesnicki, Dominika; Vuilleumier, Rodolphe; Carof, Antoine; Rotenberg, Benjamin

    2016-04-01

    The memory kernel for a tagged particle in a fluid, computed from molecular dynamics simulations, decays algebraically as t^{-3/2}. We show how the hydrodynamic Basset-Boussinesq force naturally emerges from this long-time tail and generalize the concept of hydrodynamic added mass. This mass term is negative in the present case of a molecular solute, which is at odds with incompressible hydrodynamics predictions. Lastly, we discuss the various contributions to the friction, the associated time scales, and the crossover between the molecular and hydrodynamic regimes upon increasing the solute radius. PMID:27104730

  19. Vertical axis windmill

    SciTech Connect

    Campbell, J.S.

    1980-04-08

    A vertical axis windmill is described which involves a rotatable central vertical shaft having horizontal arms pivotally supporting three sails that are free to function in the wind like the main sail on a sail boat, and means for disabling the sails to allow the windmill to be stopped in a blowing wind.

  20. Load responsive hydrodynamic bearing

    DOEpatents

    Kalsi, Manmohan S.; Somogyi, Dezso; Dietle, Lannie L.

    2002-01-01

    A load responsive hydrodynamic bearing is provided in the form of a thrust bearing or journal bearing for supporting, guiding and lubricating a relatively rotatable member to minimize wear thereof responsive to relative rotation under severe load. In the space between spaced relatively rotatable members and in the presence of a liquid or grease lubricant, one or more continuous ring shaped integral generally circular bearing bodies each define at least one dynamic surface and a plurality of support regions. Each of the support regions defines a static surface which is oriented in generally opposed relation with the dynamic surface for contact with one of the relatively rotatable members. A plurality of flexing regions are defined by the generally circular body of the bearing and are integral with and located between adjacent support regions. Each of the flexing regions has a first beam-like element being connected by an integral flexible hinge with one of the support regions and a second beam-like element having an integral flexible hinge connection with an adjacent support region. A least one local weakening geometry of the flexing region is located intermediate the first and second beam-like elements. In response to application of load from one of the relatively rotatable elements to the bearing, the beam-like elements and the local weakening geometry become flexed, causing the dynamic surface to deform and establish a hydrodynamic geometry for wedging lubricant into the dynamic interface.

  1. Hydrodynamics of pronuclear migration

    NASA Astrophysics Data System (ADS)

    Nazockdast, Ehssan; Needleman, Daniel; Shelley, Michael

    2014-11-01

    Microtubule (MT) filaments play a key role in many processes involved in cell devision including spindle formation, chromosome segregation, and pronuclear positioning. We present a direct numerical technique to simulate MT dynamics in such processes. Our method includes hydrodynamically mediated interactions between MTs and other cytoskeletal objects, using singularity methods for Stokes flow. Long-ranged many-body hydrodynamic interactions are computed using a highly efficient and scalable fast multipole method, enabling the simulation of thousands of MTs. Our simulation method also takes into account the flexibility of MTs using Euler-Bernoulli beam theory as well as their dynamic instability. Using this technique, we simulate pronuclear migration in single-celled Caenorhabditis elegans embryos. Two different positioning mechanisms, based on the interactions of MTs with the motor proteins and the cell cortex, are explored: cytoplasmic pulling and cortical pushing. We find that although the pronuclear complex migrates towards the center of the cell in both models, the generated cytoplasmic flows are fundamentally different. This suggest that cytoplasmic flow visualization during pronuclear migration can be utilized to differentiate between the two mechanisms.

  2. Hydrodynamics of Bacterial Cooperation

    NASA Astrophysics Data System (ADS)

    Petroff, A.; Libchaber, A.

    2012-12-01

    Over the course of the last several decades, the study of microbial communities has identified countless examples of cooperation between microorganisms. Generally—as in the case of quorum sensing—cooperation is coordinated by a chemical signal that diffuses through the community. Less well understood is a second class of cooperation that is mediated through physical interactions between individuals. To better understand how the bacteria use hydrodynamics to manipulate their environment and coordinate their actions, we study the sulfur-oxidizing bacterium Thiovulum majus. These bacteria live in the diffusive boundary layer just above the muddy bottoms of ponds. As buried organic material decays, sulfide diffuses out of the mud. Oxygen from the pond diffuses into the boundary layer from above. These bacteria form communities—called veils— which are able to transport nutrients through the boundary layer faster than diffusion, thereby increasing their metabolic rate. In these communities, bacteria attach to surfaces and swim in place. As millions of bacteria beat their flagella, the community induces a macroscopic fluid flow, which mix the boundary layer. Here we present experimental observations and mathematical models that elucidate the hydrodynamics linking the behavior of an individual bacterium to the collective dynamics of the community. We begin by characterizing the flow of water around an individual bacterium swimming in place. We then discuss the flow of water and nutrients around a small number of individuals. Finally, we present observations and models detailing the macroscopic dynamics of a Thiovulum veil.

  3. 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

  4. 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.

  5. 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.

  6. The one-leg standing radiograph

    PubMed Central

    Naratrikun, K.; Kanitnate, S.; Sangkomkamhang, T.

    2016-01-01

    Objectives The purpose of this study was to compare the joint space width between one-leg and both-legs standing radiographs in order to diagnose a primary osteoarthritis of the knee. Methods Digital radiographs of 100 medial osteoarthritic knees in 50 patients were performed. The patients had undergone one-leg standing anteroposterior (AP) views by standing on the affected leg while a both-legs standing AP view was undertaken while standing on both legs. The severity of the osteoarthritis was evaluated using the joint space width and Kellgren-Lawrence (KL) radiographic classification. The t-test was used for statistical analysis. Results The mean medial joint space width found in the one-leg and in the both-legs standing view were measured at 1.8 mm and 2.4 mm, respectively (p < 0.001, 95% CI 0.5 to 0.7). 33%, 47.4% and 23.1% of the knees diagnosed with a KL grade of I, II and III in the both-legs standing views were changed to KL grade II, III and IV in the one-leg standing views, respectively. No changes for KL IV osteoarthritis diagnoses have been found between both- and one-leg standing views. Conclusions One-leg standing radiographs better represent joint space width than both-legs standing radiographs. 32% of both-legs standing radiographs have changed the KL grading to a more severe grade than that in the one-leg standing radiographs. Cite this article: P. Pinsornsak, K. Naratrikun, S. Kanitnate, T. Sangkomkamhang. The one-leg standing radiograph: An improved technique to evaluate the severity of knee osteoarthritis. Bone Joint Res 2016;5:436–441. DOI: 10.1302/2046-3758.59.BJR-2016-0049.R1. PMID:27683299

  7. 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.

  8. Pitfalls in the radiographic diagnosis of angiofibroma.

    PubMed

    Shaffer, K; Haughton, V; Farley, G; Friedman, J

    1978-05-01

    Radiographic findings previously thought pathognomonic for juvenile nasopharyngeal angiofibroma are anterior bowing of the posterior wall of the maxillary antrum on plain films or tomography, and a dense homogeneous blush on angiography. Two patients presented with nasopharyngeal masses which mimicked angiofibroma radiographically: one mass was a lymphoepithelioma and the other was a fibrous tumor. Constitutional symptoms and atypical physical findings should alert the physician to a diagnosis other than juvenile nasopharyngeal angiofibroma.

  9. [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

  10. Automation of arthritis measures in hand radiographs

    NASA Astrophysics Data System (ADS)

    Levitt, Tod S.; Hedgcock, Marcus W.; Dye, John; Johnston, Scott E.

    1990-07-01

    Hand radiographs provide a valuable index of disease in arthritis and other generalized diseases such as secondary hyperparathyroidism and osteoporosis. Measures such as cortical volume intercortical width average and periarticular demineralization provide diagnostic indicators for these diseases. However visual analysis of hand radiographs is not quantitative and is compromised by both interobserver and intraobserver variation. Automation of these measures would provide repeatable comparable quantities to assist in diagnosis and disease and therapy monitoring. The computer calculations to perform these measures are straightforward. The key problem is automatic segmentation of the hand anatomy that is recognizing the pixels that correspond to specific imaged bones and joints. Our approach incorporates computer-represented hand models in addition to more traditional image processing algorithms. We describe our techniques for using a combination of predictive models and image processing evidence to automatically fmd bone and tissue boundaries and identify specific bone and joints. 2. COMPUTING ARTHRITIS MEASURES Digital scanners and radiograph digitizers make the radiograph available as a data source for computer algorithms that analyze medical imagery. This is significant because radiographs comprise more than 80 of all medical imagery at this time and they are considerably quicker and less costly than other digital modalities such as CT and Mill. Quantitative measures from digital radiographs can aid physicians in diagnosis tracking disease progress and in therapy planning and evaluation. We have begun studying diagnostic measures in arthritis

  11. General formulation of transverse hydrodynamics

    SciTech Connect

    Ryblewski, Radoslaw; Florkowski, Wojciech

    2008-06-15

    General formulation of hydrodynamics describing transversally thermalized matter created at the early stages of ultrarelativistic heavy-ion collisions is presented. Similarities and differences with the standard three-dimensionally thermalized relativistic hydrodynamics are discussed. The role of the conservation laws as well as the thermodynamic consistency of two-dimensional thermodynamic variables characterizing transversally thermalized matter is emphasized.

  12. Hydrodynamics of Peristaltic Propulsion

    NASA Astrophysics Data System (ADS)

    Athanassiadis, Athanasios; Hart, Douglas

    2014-11-01

    A curious class of animals called salps live in marine environments and self-propel by ejecting vortex rings much like jellyfish and squid. However, unlike other jetting creatures that siphon and eject water from one side of their body, salps produce vortex rings by pumping water through siphons on opposite ends of their hollow cylindrical bodies. In the simplest cases, it seems like some species of salp can successfully move by contracting just two siphons connected by an elastic body. When thought of as a chain of timed contractions, salp propulsion is reminiscent of peristaltic pumping applied to marine locomotion. Inspired by salps, we investigate the hydrodynamics of peristaltic propulsion, focusing on the scaling relationships that determine flow rate, thrust production, and energy usage in a model system. We discuss possible actuation methods for a model peristaltic vehicle, considering both the material and geometrical requirements for such a system.

  13. Hydrodynamics, resurgence, and transasymptotics

    NASA Astrophysics Data System (ADS)

    Başar, Gökçe; Dunne, Gerald V.

    2015-12-01

    The second order hydrodynamical description of a homogeneous conformal plasma that undergoes a boost-invariant expansion is given by a single nonlinear ordinary differential equation, whose resurgent asymptotic properties we study, developing further the recent work of Heller and Spalinski [Phys. Rev. Lett. 115, 072501 (2015)]. Resurgence clearly identifies the nonhydrodynamic modes that are exponentially suppressed at late times, analogous to the quasinormal modes in gravitational language, organizing these modes in terms of a trans-series expansion. These modes are analogs of instantons in semiclassical expansions, where the damping rate plays the role of the instanton action. We show that this system displays the generic features of resurgence, with explicit quantitative relations between the fluctuations about different orders of these nonhydrodynamic modes. The imaginary part of the trans-series parameter is identified with the Stokes constant, and the real part with the freedom associated with initial conditions.

  14. Hydrodynamic effects on coalescence.

    SciTech Connect

    Dimiduk, Thomas G.; Bourdon, Christopher Jay; Grillet, Anne Mary; Baer, Thomas A.; de Boer, Maarten Pieter; Loewenberg, Michael; Gorby, Allen D.; Brooks, Carlton, F.

    2006-10-01

    The goal of this project was to design, build and test novel diagnostics to probe the effect of hydrodynamic forces on coalescence dynamics. Our investigation focused on how a drop coalesces onto a flat surface which is analogous to two drops coalescing, but more amenable to precise experimental measurements. We designed and built a flow cell to create an axisymmetric compression flow which brings a drop onto a flat surface. A computer-controlled system manipulates the flow to steer the drop and maintain a symmetric flow. Particle image velocimetry was performed to confirm that the control system was delivering a well conditioned flow. To examine the dynamics of the coalescence, we implemented an interferometry capability to measure the drainage of the thin film between the drop and the surface during the coalescence process. A semi-automated analysis routine was developed which converts the dynamic interferogram series into drop shape evolution data.

  15. 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.

  16. Multiple axis reticle

    NASA Technical Reports Server (NTRS)

    Barns, Chris E. (Inventor); Gunter, William D. (Inventor)

    1990-01-01

    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.

  17. Hydrodynamics of sediment threshold

    NASA Astrophysics Data System (ADS)

    Ali, Sk Zeeshan; Dey, Subhasish

    2016-07-01

    A novel hydrodynamic model for the threshold of cohesionless sediment particle motion under a steady unidirectional streamflow is presented. The hydrodynamic forces (drag and lift) acting on a solitary sediment particle resting over a closely packed bed formed by the identical sediment particles are the primary motivating forces. The drag force comprises of the form drag and form induced drag. The lift force includes the Saffman lift, Magnus lift, centrifugal lift, and turbulent lift. The points of action of the force system are appropriately obtained, for the first time, from the basics of micro-mechanics. The sediment threshold is envisioned as the rolling mode, which is the plausible mode to initiate a particle motion on the bed. The moment balance of the force system on the solitary particle about the pivoting point of rolling yields the governing equation. The conditions of sediment threshold under the hydraulically smooth, transitional, and rough flow regimes are examined. The effects of velocity fluctuations are addressed by applying the statistical theory of turbulence. This study shows that for a hindrance coefficient of 0.3, the threshold curve (threshold Shields parameter versus shear Reynolds number) has an excellent agreement with the experimental data of uniform sediments. However, most of the experimental data are bounded by the upper and lower limiting threshold curves, corresponding to the hindrance coefficients of 0.2 and 0.4, respectively. The threshold curve of this study is compared with those of previous researchers. The present model also agrees satisfactorily with the experimental data of nonuniform sediments.

  18. Constraining relativistic viscous hydrodynamical evolution

    SciTech Connect

    Martinez, Mauricio; Strickland, Michael

    2009-04-15

    We show that by requiring positivity of the longitudinal pressure it is possible to constrain the initial conditions one can use in second-order viscous hydrodynamical simulations of ultrarelativistic heavy-ion collisions. We demonstrate this explicitly for (0+1)-dimensional viscous hydrodynamics and discuss how the constraint extends to higher dimensions. Additionally, we present an analytic approximation to the solution of (0+1)-dimensional second-order viscous hydrodynamical evolution equations appropriate to describe the evolution of matter in an ultrarelativistic heavy-ion collision.

  19. 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.

  20. Spin hydrodynamic generation

    NASA Astrophysics Data System (ADS)

    Takahashi, R.; Matsuo, M.; Ono, M.; Harii, K.; Chudo, H.; Okayasu, S.; Ieda, J.; Takahashi, S.; Maekawa, S.; Saitoh, E.

    2016-01-01

    Magnetohydrodynamic generation is the conversion of fluid kinetic energy into electricity. Such conversion, which has been applied to various types of electric power generation, is driven by the Lorentz force acting on charged particles and thus a magnetic field is necessary. On the other hand, recent studies of spintronics have revealed the similarity between the function of a magnetic field and that of spin-orbit interactions in condensed matter. This suggests the existence of an undiscovered route to realize the conversion of fluid dynamics into electricity without using magnetic fields. Here we show electric voltage generation from fluid dynamics free from magnetic fields; we excited liquid-metal flows in a narrow channel and observed longitudinal voltage generation in the liquid. This voltage has nothing to do with electrification or thermoelectric effects, but turned out to follow a universal scaling rule based on a spin-mediated scenario. The result shows that the observed voltage is caused by spin-current generation from a fluid motion: spin hydrodynamic generation. The observed phenomenon allows us to make mechanical spin-current and electric generators, opening a door to fluid spintronics.

  1. Hydrodynamics of micropipette aspiration.

    PubMed Central

    Drury, J L; Dembo, M

    1999-01-01

    The dynamics of human neutrophils during micropipette aspiration are frequently analyzed by approximating these cells as simple slippery droplets of viscous fluid. Here, we present computations that reveal the detailed predictions of the simplest and most idealized case of such a scheme; namely, the case where the fluid of the droplet is homogeneous and Newtonian, and the surface tension of the droplet is constant. We have investigated the behavior of this model as a function of surface tension, droplet radius, viscosity, aspiration pressure, and pipette radius. In addition, we have tabulated a dimensionless factor, M, which can be utilized to calculate the apparent viscosity of the slippery droplet. Computations were carried out using a low Reynolds number hydrodynamics transport code based on the finite-element method. Although idealized and simplistic, we find that the slippery droplet model predicts many observed features of neutrophil aspiration. However, there are certain features that are not observed in neutrophils. In particular, the model predicts dilation of the membrane past the point of being continuous, as well as a reentrant jet at high aspiration pressures. PMID:9876128

  2. [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

  3. 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.

  4. 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.

  5. [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.

  6. Giant colonic diverticulum: radiographic and MDCT characteristics.

    PubMed

    Zeina, Abdel-Rauf; Mahamid, Ahmad; Nachtigal, Alicia; Ashkenazi, Itamar; Shapira-Rootman, Mika

    2015-12-01

    Giant colonic diverticulum (GCD), defined as a diverticulum larger than 4 cm, is a rare entity that is generally a manifestation of colonic diverticular disease. Because of its rarity and its variable and non-specific presentation, the diagnosis of GCD depends mainly on imaging findings. Knowledge of the spectrum of radiographic and CT features of the GCD is important in making the correct diagnosis and potentially preventing complications. This review focuses on imaging findings characteristic of GCD as well as its complications and radiographic mimics. Teaching points • Giant colonic diverticulum is a rare complication of diverticulosis.• The most common symptom is abdominal pain presenting in approximately 70 % of patients.• Diagnosis is based on imaging findings with plain abdominal radiographs and MDCT.• Treatment consists of en bloc resection of the diverticulum and affected adjacent colon.

  7. 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.

  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. Instant slides of radiographs for lectures.

    PubMed

    Rothstein, S G; Stewart, P L

    1989-10-01

    High quality slides of radiographs may be made with a simple, fast, and inexpensive technique using Kodak Rapid Process Copy film. Lecture presentations may include a slide of a pertinent plain radiograph, computed tomography (CT) scan, or magnetic resonance imaging (MRI). Although these slides may be made with a 35 mm SLR camera and flash or with a 35 mm SLR camera and a lighted viewbox, an alternative method is available that is easy to perform, inexpensive, and can produce quality slides in as little as 30 minutes. PMID:2477785

  10. Hydrodynamic synchronization of colloidal oscillators

    PubMed Central

    Kotar, Jurij; Leoni, Marco; Bassetti, Bruno; Lagomarsino, Marco Cosentino; Cicuta, Pietro

    2010-01-01

    Two colloidal spheres are maintained in oscillation by switching the position of an optical trap when a sphere reaches a limit position, leading to oscillations that are bounded in amplitude but free in phase and period. The interaction between the oscillators is only through the hydrodynamic flow induced by their motion. We prove that in the absence of stochastic noise the antiphase dynamical state is stable, and we show how the period depends on coupling strength. Both features are observed experimentally. As the natural frequencies of the oscillators are made progressively different, the coordination is quickly lost. These results help one to understand the origin of hydrodynamic synchronization and how the dynamics can be tuned. Cilia and flagella are biological systems coupled hydrodynamically, exhibiting dramatic collective motions. We propose that weakly correlated phase fluctuations, with one of the oscillators typically precessing the other, are characteristic of hydrodynamically coupled systems in the presence of thermal noise. PMID:20385848

  11. Reciprocal relations in dissipationless hydrodynamics

    SciTech Connect

    Melnikovsky, L. A.

    2014-12-15

    Hidden symmetry in dissipationless terms of arbitrary hydrodynamics equations is recognized. We demonstrate that all fluxes are generated by a single function and derive conventional Euler equations using the proposed formalism.

  12. Relativistic hydrodynamics on graphic cards

    NASA Astrophysics Data System (ADS)

    Gerhard, Jochen; Lindenstruth, Volker; Bleicher, Marcus

    2013-02-01

    We show how to accelerate relativistic hydrodynamics simulations using graphic cards (graphic processing units, GPUs). These improvements are of highest relevance e.g. to the field of high-energetic nucleus-nucleus collisions at RHIC and LHC where (ideal and dissipative) relativistic hydrodynamics is used to calculate the evolution of hot and dense QCD matter. The results reported here are based on the Sharp And Smooth Transport Algorithm (SHASTA), which is employed in many hydrodynamical models and hybrid simulation packages, e.g. the Ultrarelativistic Quantum Molecular Dynamics model (UrQMD). We have redesigned the SHASTA using the OpenCL computing framework to work on accelerators like graphic processing units (GPUs) as well as on multi-core processors. With the redesign of the algorithm the hydrodynamic calculations have been accelerated by a factor 160 allowing for event-by-event calculations and better statistics in hybrid calculations.

  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.

  14. Will it hurt? Verbal interaction between child and radiographer during radiographic examination.

    PubMed

    Björkman, Berit; Golsäter, Marie; Simeonson, Rune J; Enskär, Karin

    2013-01-01

    This study investigated the nature of verbal interactions between child, parent and radiographer and the extent to which it varied as a function of the child's age. The participants were 20 female radiographers and 32 children (3-15 years) examined for acute injuries. The verbal interactions during the examination were video recorded and analyzed using the Roter Interaction Analysis System (RIAS). Results indicated that 80% of the verbal interaction was accounted for by the radiographer, 17% by the child and 3% by the parent. The distribution of utterances varied with regard to children's age. PMID:23619022

  15. Hydrodynamic escape from planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Tian, Feng

    Hydrodynamic escape is an important process in the formation and evolution of planetary atmospheres. Due to the existence of a singularity point near the transonic point, it is difficult to find transonic steady state solutions by solving the time-independent hydrodynamic equations. In addition to that, most previous works assume that all energy driving the escape flow is deposited in one narrow layer. This assumption not only results in less accurate solutions to the hydrodynamic escape problem, but also makes it difficult to include other chemical and physical processes in the hydrodynamic escape models. In this work, a numerical model describing the transonic hydrodynamic escape from planetary atmospheres is developed. A robust solution technique is used to solve the time dependent hydrodynamic equations. The method has been validated in an isothermal atmosphere where an analytical solution is available. The hydrodynamic model is applied to 3 cases: hydrogen escape from small orbit extrasolar planets, hydrogen escape from a hydrogen rich early Earth's atmosphere, and nitrogen/methane escape from Pluto's atmosphere. Results of simulations on extrasolar planets are in good agreement with the observations of the transiting extrasolar planet HD209458b. Hydrodynamic escape of hydrogen from other hypothetical close-in extrasolar planets are simulated and the influence of hydrogen escape on the long-term evolution of these extrasolar planets are discussed. Simulations on early Earth suggest that hydrodynamic escape of hydrogen from a hydrogen rich early Earth's atmosphere is about two orders magnitude slower than the diffusion limited escape rate. A hydrogen rich early Earth's atmosphere could have been maintained by the balance between the hydrogen escape and the supply of hydrogen into the atmosphere by volcanic outgassing. Origin of life may have occurred in the organic soup ocean created by the efficient formation of prebiotic molecules in the hydrogen rich early

  16. Hinged, Magnetic Holder For Radiographic Film

    NASA Technical Reports Server (NTRS)

    Pierce, Darryl E.

    1989-01-01

    Hinged holder equipped with magnets enables positive, accurate, and repeatable placement and orientation of radiographic film at hidden and otherwise inaccessible location. Made from simple, readily available parts. Film and holder inserted in end of duct and pulled along by magnets on outside. Holder removed by reversing sequence of motions.

  17. 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.

  18. 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

  19. The radiographic investigation of two Egyptian mummies.

    PubMed

    Fodor, J; Malott, J C; King, A Y

    1983-01-01

    Radiography is a well-recognized method of nondestructive analysis of art objects and ancient relics. The methods and techniques used in the examination of two ancient Egyptian mummies are presented here. Additionally, the use of radiographic findings to help substantiate alleged historical information and to establish sex, age, and pathology of each specimen is discussed.

  20. 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.

  1. 21 CFR 892.1910 - Radiographic grid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Radiographic grid. 892.1910 Section 892.1910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL... placed between the patient and the image receptor to reduce the amount of scattered radiation...

  2. 21 CFR 892.1910 - Radiographic grid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Radiographic grid. 892.1910 Section 892.1910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL... placed between the patient and the image receptor to reduce the amount of scattered radiation...

  3. 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…

  4. Image rejects/retakes--radiographic challenges.

    PubMed

    Waaler, D; Hofmann, B

    2010-01-01

    A general held position among radiological personnel prior to digitalisation was that the problem of image rejects/retakes should more or less vanish. However, rejects/retakes still impose several challenges within radiographic imaging; they occupy unnecessary resources, expose patients to unnecessary ionizing radiation and may also indicate suboptimal quality management. The latter is the main objective of this paper, which is based on a survey of international papers published both for screen/film and digital technology. The digital revolution in imaging seems to have reduced the percentage of image rejects/retakes from 10-15 to 3-5 %. The major contribution to the decrease appears to be the dramatic reduction of incorrect exposures. At the same time, rejects/retakes due to lack of operator competence (positioning, etc.) are almost unchanged, or perhaps slightly increased (due to lack of proper technical competence, incorrect organ coding, etc.). However, the causes of rejects/retakes are in many cases defined and reported with reference to radiographers' subjective evaluations. Thus, unless radiographers share common views on image quality and acceptance criteria, objective measurements and assessments of reject/retake rates are challenging tasks. Interestingly, none of the investigated papers employs image quality parameters such as 'too much noise' as categories for rejects/retakes. Surprisingly, no reject/retake analysis seems yet to have been conducted for direct digital radiography departments. An increased percentage of rejects/retakes is related to 'digital skills' of radiographers and therefore points to areas for extended education and training. Furthermore, there is a need to investigate the inter-subjectivity of radiographers' perception of, and attitude towards, both technical and clinical image quality criteria. Finally, there may be a need to validate whether reject/retake rate analysis is such an effective quality indicator as has been asserted

  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. 21 CFR 892.1850 - Radiographic film cassette.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) Identification. A radiographic film cassette is a device intended for use during diagnostic x-ray procedures to hold a radiographic film in close contact with an x-ray intensifying screen and to provide a...

  7. 21 CFR 892.1850 - Radiographic film cassette.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) Identification. A radiographic film cassette is a device intended for use during diagnostic x-ray procedures to hold a radiographic film in close contact with an x-ray intensifying screen and to provide a...

  8. 21 CFR 892.1850 - Radiographic film cassette.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) Identification. A radiographic film cassette is a device intended for use during diagnostic x-ray procedures to hold a radiographic film in close contact with an x-ray intensifying screen and to provide a...

  9. 21 CFR 892.1850 - Radiographic film cassette.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...) Identification. A radiographic film cassette is a device intended for use during diagnostic x-ray procedures to hold a radiographic film in close contact with an x-ray intensifying screen and to provide a...

  10. Maxwell-Chern-Simons hydrodynamics for the chiral magnetic effect

    SciTech Connect

    Oezoender, Sener

    2010-06-15

    The rate of vacuum-changing topological solutions of the gluon field, sphalerons, is estimated to be large at the typical temperatures of heavy-ion collisions, particularly at the Relativistic Heavy Ion Collider. Such windings in the gluon field are expected to produce parity-odd bubbles, which cause separation of positively and negatively charged quarks along the axis of the external magnetic field. This chiral magnetic effect can be mimicked by Chern-Simons modified electromagnetism. Here we present a model of relativistic hydrodynamics including the effects of axial anomalies via the Chern-Simons term.

  11. 21 CFR 892.1970 - Radiographic ECG/respirator synchronizer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 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...

  12. 10 CFR 34.33 - Permanent radiographic installations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Permanent radiographic installations. 34.33 Section 34.33 Energy NUCLEAR REGULATORY COMMISSION LICENSES FOR INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Equipment § 34.33 Permanent radiographic installations....

  13. 10 CFR 34.33 - Permanent radiographic installations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Permanent radiographic installations. 34.33 Section 34.33 Energy NUCLEAR REGULATORY COMMISSION LICENSES FOR INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Equipment § 34.33 Permanent radiographic installations....

  14. 21 CFR 892.1920 - Radiographic head holder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Radiographic head holder. 892.1920 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1920 Radiographic head holder. (a) Identification. A radiographic head holder is a device intended to position the patient's head during...

  15. 21 CFR 892.1920 - Radiographic head holder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic head holder. 892.1920 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1920 Radiographic head holder. (a) Identification. A radiographic head holder is a device intended to position the patient's head during...

  16. 21 CFR 892.1920 - Radiographic head holder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Radiographic head holder. 892.1920 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1920 Radiographic head holder. (a) Identification. A radiographic head holder is a device intended to position the patient's head during...

  17. 21 CFR 892.1920 - Radiographic head holder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Radiographic head holder. 892.1920 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1920 Radiographic head holder. (a) Identification. A radiographic head holder is a device intended to position the patient's head during...

  18. 21 CFR 892.1920 - Radiographic head holder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Radiographic head holder. 892.1920 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1920 Radiographic head holder. (a) Identification. A radiographic head holder is a device intended to position the patient's head during...

  19. 21 CFR 892.1850 - Radiographic film cassette.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic film cassette. 892.1850 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1850 Radiographic film cassette. (a) Identification. A radiographic film cassette is a device intended for use during diagnostic x-ray procedures...

  20. 21 CFR 892.1900 - Automatic radiographic film processor.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Automatic radiographic film processor. 892.1900... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1900 Automatic radiographic film processor. (a) Identification. An automatic radiographic film processor is a device intended to be used...

  1. 21 CFR 892.1860 - Radiographic film/cassette changer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic film/cassette changer. 892.1860... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1860 Radiographic film/cassette changer. (a) Identification. A radiographic film/cassette changer is a device intended to be used during...

  2. 21 CFR 892.1890 - Radiographic film illuminator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic film illuminator. 892.1890 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1890 Radiographic film illuminator. (a) Identification. A radiographic film illuminator is a device containing a visible light source covered with...

  3. 21 CFR 892.1640 - Radiographic film marking system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic film marking system. 892.1640 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1640 Radiographic film marking system. (a) Identification. A radiographic film marking system is a device intended for medical purposes...

  4. 21 CFR 892.1640 - Radiographic film marking system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Radiographic film marking system. 892.1640 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1640 Radiographic film marking system. (a) Identification. A radiographic film marking system is a device intended for medical purposes...

  5. 21 CFR 892.1860 - Radiographic film/cassette changer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Radiographic film/cassette changer. 892.1860... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1860 Radiographic film/cassette changer. (a) Identification. A radiographic film/cassette changer is a device intended to be used during...

  6. 21 CFR 892.1890 - Radiographic film illuminator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Radiographic film illuminator. 892.1890 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1890 Radiographic film illuminator. (a) Identification. A radiographic film illuminator is a device containing a visible light source covered with...

  7. 21 CFR 892.1900 - Automatic radiographic film processor.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Automatic radiographic film processor. 892.1900... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1900 Automatic radiographic film processor. (a) Identification. An automatic radiographic film processor is a device intended to be used...

  8. 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...

  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. Black brane entropy and hydrodynamics

    SciTech Connect

    Booth, Ivan; Heller, Michal P.; Spalinski, Michal

    2011-03-15

    Recent advances in holography have led to the formulation of fluid-gravity duality, a remarkable connection between the hydrodynamics of certain strongly coupled media and dynamics of higher dimensional black holes. This paper introduces a correspondence between phenomenologically defined entropy currents in relativistic hydrodynamics and 'generalized horizons' of near-equilibrium black objects in a dual gravitational description. A general formula is given, expressing the divergence of the entropy current in terms of geometric objects which appear naturally in the gravity dual geometry. The proposed definition is explicitly covariant with respect to boundary diffeomorphisms and reproduces known results when evaluated for the event horizon.

  11. Abnormal pressures as hydrodynamic phenomena

    USGS Publications Warehouse

    Neuzil, C.E.

    1995-01-01

    So-called abnormal pressures, subsurface fluid pressures significantly higher or lower than hydrostatic, have excited speculation about their origin since subsurface exploration first encountered them. Two distinct conceptual models for abnormal pressures have gained currency among earth scientists. The static model sees abnormal pressures generally as relict features preserved by a virtual absence of fluid flow over geologic time. The hydrodynamic model instead envisions abnormal pressures as phenomena in which flow usually plays an important role. This paper develops the theoretical framework for abnormal pressures as hydrodynamic phenomena, shows that it explains the manifold occurrences of abnormal pressures, and examines the implications of this approach. -from Author

  12. Imaging x-ray fluorescence relevant to hydrodynamic mixing experiments at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    MacDonald, Michael; Gamboa, Eliseo; Kuranz, Carolyn; Keiter, Paul; Drake, R. Paul

    2012-10-01

    The National Ignition Facility (NIF) is capable of providing enough energy to explore areas of physics that are not possible on any previous laser system. This includes large-volume, geometrically complex hydrodynamic and radiation hydrodynamic experiments in which traditional, line-integrated radiographic techniques limit the quality of the results. As an example, we are involved in divergent hydrodynamic experiments at the NIF, motivated by supernova hydrodynamics, that cannot be diagnosed in detail with transmission radiography. X-ray scattering has been considered for this purpose and appears feasible [1]. Here we consider fluorescence imaging, a better candidate as the cross section of photoabsorption in the several-keV range is roughly 100 times larger than that of scattering. A single layer of the target will be uniformly doped with a fluorescent tracer, which will be pumped by a sheet of x-rays. The fluorescent intensity will be measured to create a density map of the doped material as it mixes with other layers. Developing this diagnostic will create a powerful tool to characterize hydrodynamic experiments with complex geometries.[4pt] [1] Huntington et al. High Energy Density Physics 6, 194 (2010).

  13. Enhancement of chest radiographs using eigenimage processing

    NASA Astrophysics Data System (ADS)

    Bones, Philip J.; Butler, Anthony P. H.; Hurrell, Michael

    2006-08-01

    Frontal chest radiographs ("chest X-rays") are routinely used by medical personnel to assess patients for a wide range of suspected disorders. Often large numbers of images need to be analyzed. Furthermore, at times the images need to analyzed ("reported") when no radiological expert is available. A system which enhances the images in such a way that abnormalities are more obvious is likely to reduce the chance that an abnormality goes unnoticed. The authors previously reported the use of principal components analysis to derive a basis set of eigenimages from a training set made up of images from normal subjects. The work is here extended to investigate how best to emphasize the abnormalities in chest radiographs. Results are also reported for various forms of image normalizing transformations used in performing the eigenimage processing.

  14. [Radiographic diagnosis of vertical root fracture].

    PubMed

    Guangning, Zheng; Jiyao, Li

    2016-02-01

    Vertical root fracture (VRF) is different from odontoclasis caused by trauma or injury. VRF is defined as a complete or incomplete fracture of roots caused by long-term and persistent stimulus, such as excessive forces from mastication or occlusion, improper tooth anatomy, and tooth treatment accident. Early diagnosis of VRF is essential to prevent the absorption of alveolar bone, thereby improving prognosis. Radiographic examination is the most common and effective evaluation method for VRF. Cone beam computed tomography can provide three-dimensional information for fracture details, which are more precise than traditional periapical films. In this paper, we present the radiographic features, differential diagnosis, and new treatment techniques for VRF. PMID:27266189

  15. Clinical and radiographic maxillofacial features of pycnodysostosis

    PubMed Central

    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

  16. Radiation energy transport through hydrodynamically evolving slits

    NASA Astrophysics Data System (ADS)

    Foster, J. M.; Graham, P.; Taylor, M.; Moore, A.; Sorce, C.; Reighard, A.; MacLaren, S.; Young, P.; Glendinning, G.; Blue, B.; Back, C.; Hund, J.

    2008-11-01

    Radiation transport through enclosed spaces with inwardly moving walls is a key component of the physics of laser-heated hohlraums. It arises in the cavity itself (where inward motion of the wall results in late-time stagnation of dense plasma on the hohlraum axis), and also in the laser-entry and diagnostic holes (where an understanding of hole-closure is important to hohlraum design and the interpretation of diagnostic data). To understand these phenomena better, we have carried out a series of experiments at the Omega laser facility. A laser-heated hohlraum is used to illuminate linear and annular slits machined in samples of solid-density tantalum and low-density, tantalum-oxide foam. Measurements of the transmitted energy are made indirectly (by measuring the temperature rise of a ``calorimeter'' hohlraum) and directly (by measuring the emission from the slit component, using a target in which the calorimeter hohlraum was omitted). The hydrodynamics is investigated by self-emission and absorption (backlighting) x-ray imaging of the closing slits. Simulations (using a 2-D Eulerian hydrocode) reproduce the overall energetics, the detail of the deceleration shock and axial stagnation region at the centre of the slit, and the complex shock interactions that occur at corners of the slits.

  17. Hydrodynamic slip in silicon nanochannels

    NASA Astrophysics Data System (ADS)

    Ramos-Alvarado, Bladimir; Kumar, Satish; Peterson, G. P.

    2016-03-01

    Equilibrium and nonequilibrium molecular dynamics simulations were performed to better understand the hydrodynamic behavior of water flowing through silicon nanochannels. The water-silicon interaction potential was calibrated by means of size-independent molecular dynamics simulations of silicon wettability. The wettability of silicon was found to be dependent on the strength of the water-silicon interaction and the structure of the underlying surface. As a result, the anisotropy was found to be an important factor in the wettability of these types of crystalline solids. Using this premise as a fundamental starting point, the hydrodynamic slip in nanoconfined water was characterized using both equilibrium and nonequilibrium calculations of the slip length under low shear rate operating conditions. As was the case for the wettability analysis, the hydrodynamic slip was found to be dependent on the wetted solid surface atomic structure. Additionally, the interfacial water liquid structure was the most significant parameter to describe the hydrodynamic boundary condition. The calibration of the water-silicon interaction potential performed by matching the experimental contact angle of silicon led to the verification of the no-slip condition, experimentally reported for silicon nanochannels at low shear rates.

  18. Topics in fluctuating nonlinear hydrodynamics

    SciTech Connect

    Milner, S.T.

    1986-01-01

    Models of fluctuating nonlinear hydrodynamics have enjoyed much success in explaining the effect of long-wavelength fluctuations in diverse hydrodynamic systems. This thesis explores two such problems; in both, the body of hydrodynamic assumptions powerfully constrains the predictions of a well-posed theory. The effects of layer fluctuations in smectic-A liquid crystals are first examined. The static theory (introduced by Grinstein and Pelcovits) is reviewed. Ward identities, resulting from the arbitrariness of the layering direction, are derived and exploited. The static results motivate an examination of dynamic fluctuation effects. A new sound-damping experiment is proposed that would probe singular dependence of viscosities on applied stress. A theory of Procaccia and Gitterman that reaction rates of chemically reacting binary mixtures are drastically reduced near their thermodynamic critical points is analyzed. Hydrodynamic arguments and Van Hove theory are applied, concluding that the PG idea is drastically slowed, and spatially varying composition fluctuations are at best slowed down over a narrow range of wavenumbers.

  19. 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

  20. Axis I and Axis II diagnostic parameters of homicide.

    PubMed

    Yarvis, R M

    1990-01-01

    A series of 100 murderers was examined to discern overall patterns of psychopathology. In addition, demographic and other discriminating factors were used to test the hypothesis that murderers do not constitute a homogenous population and that subgroups will differ diagnostically. DSM-III diagnostic criteria were used to make each diagnosis. The sample was found to be representative of the universe from which it was drawn at least as could be determined by available comparative criteria. Four Axis I (psychoses, substance abuse, dysthymia, no Axis I) and three Axis II (antisocial, borderline, no Axis II) diagnostic categories accounted for more than 80 percent of the study population. The murderers were found to be a heterogenous population, and subgroups based on a combination of assailant's crime pattern, sex, prior criminal history, and relationship to victim manifested different prevailing diagnostic patterns.

  1. Numerical simulation of hydrodynamic flows in the jet electric

    NASA Astrophysics Data System (ADS)

    Sarychev, V. D.; Granovskii, A. Yu; Nevskii, S. A.

    2016-02-01

    On the basis of concepts from magnetic hydrodynamics the mathematical model of hydrodynamic flows in the stream of electric arc plasma, obtained between the rod electrode and the target located perpendicular to the flat conductive, was developed. The same phenomenon occurs in the welding arc, arc plasma and other injection sources of charged particles. The model is based on the equations of magnetic hydrodynamics with special boundary conditions. The obtained system of equations was solved by the numerical method of finite elements with an automatic selection of the time step. Calculations were carried out with regard to the normal plasma inleakage on the solid conducting surface and the surface with the orifice. It was found that the solid surface facilitates three swirling zones. Interaction of these zones leads to the formation of two stable swirling zones, one of which is located at a distance of two radii from the axis and midway between the electrodes, another is located in the immediate vicinity of the continuous electrode. In this zone plasma backflow scattering fine particles is created. Swirling zones are not formed by using the plane electrode with an orifice. Thus, the fine particles can pass through it and consolidate.

  2. Three-dimensional Numerical Analysis on Blade Response of Vertical Axis Tidal Current Turbine Under Operational Condition

    SciTech Connect

    Li, Ye; Karri, Naveen K.; Wang, Qi

    2014-04-30

    Tidal power as a large-scale renewable source of energy has been receiving significant attention recently because of its advantages over the wind and other renewal energy sources. The technology used to harvest energy from tidal current is called a tidal current turbine. Though some of the principles of wind turbine design are applicable to tidal current turbines, the design of latter ones need additional considerations like cavitation damage, corrosion etc. for the long-term reliability of such turbines. Depending up on the orientation of axis, tidal current turbines can be classified as vertical axis turbines or horizontal axis turbines. Existing studies on the vertical axis tidal current turbine focus more on the hydrodynamic aspects of the turbine rather than the structural aspects. This paper summarizes our recent efforts to study the integrated hydrodynamic and structural aspects of the vertical axis tidal current turbines. After reviewing existing methods in modeling tidal current turbines, we developed a hybrid approach that combines discrete vortex method -finite element method that can simulate the integrated hydrodynamic and structural response of a vertical axis turbine. This hybrid method was initially employed to analyze a typical three-blade vertical axis turbine. The power coefficient was used to evaluate the hydrodynamic performance, and critical deflection was considered to evaluate the structural reliability. A sensitivity analysis was also conducted with various turbine height-to-radius ratios. The results indicate that both the power output and failure probability increase with the turbine height, suggesting a necessity for optimal design. An attempt to optimize a 3-blade vertical axis turbine design with hybrid method yielded a ratio of turbine height to radius (H/R) about 3.0 for reliable maximum power output.

  3. Mesiodens: a radiographic study in children.

    PubMed

    Gündüz, Kaan; Celenk, Peruze; Zengin, Zeynep; Sümer, Pinar

    2008-09-01

    We analyzed the frequency and radiological features of mesiodens in a group of children in Turkey. The study was based on a radiographic review of 23,000 pediatric patients (male: 12,667 female; 10,333) who visited the Department of Oral Diagnosis and Radiology during the period 2003-2005 (3 years). The presence of an unerupted supernumerary tooth, or tooth bud between the 2 central incisors or as unilateral or bilateral teeth in the midline of the maxilla was noted as mesiodens on radiographs. Eighty-five cases of mesiodens in 69 patients were found. Complete documentation, including radiographs, for these 69 patients were studied and analyzed. In addition to gender and age, the following information about the mesiodens was recorded: 1) number; 2) shape; 3) position; 4) complications caused by the mesiodens; 5) treatment. Of the 69 patients, the ratio of boys (47 cases) to girls (22 cases) was 2.1:1. Fifty-three (76.8%) of the children had 1 mesiodens, and 16 (23.1%) had 2 mesiodentes bilaterally to the midline. Of the 85 mesiodentes, 67 (78.8%) were fully impacted, 6 (7%) were partially erupted, and 12 (14.1%) were fully erupted. Most of the mesiodentes (55.2%) were found in the vertical position, followed by inverted position (37.6%), and horizontal position (7%). The main complications were delayed eruption of the permanent incisors (38.8%), maxillary midline diastema (17.6%), axial rotation or inclination of erupted permanent incisors (16.4%), and resorption of the adjacent teeth (4.7%) The prevelance of mesiodens has been estimated to be 0.15% to 2.2% of the population. PMID:18818464

  4. Segmentation of ribs in digital chest radiographs

    NASA Astrophysics Data System (ADS)

    Cong, Lin; Guo, Wei; Li, Qiang

    2016-03-01

    Ribs and clavicles in posterior-anterior (PA) digital chest radiographs often overlap with lung abnormalities such as nodules, and cause missing of these abnormalities, it is therefore necessary to remove or reduce the ribs in chest radiographs. The purpose of this study was to develop a fully automated algorithm to segment ribs within lung area in digital radiography (DR) for removal of the ribs. The rib segmentation algorithm consists of three steps. Firstly, a radiograph was pre-processed for contrast adjustment and noise removal; second, generalized Hough transform was employed to localize the lower boundary of the ribs. In the third step, a novel bilateral dynamic programming algorithm was used to accurately segment the upper and lower boundaries of ribs simultaneously. The width of the ribs and the smoothness of the rib boundaries were incorporated in the cost function of the bilateral dynamic programming for obtaining consistent results for the upper and lower boundaries. Our database consisted of 93 DR images, including, respectively, 23 and 70 images acquired with a DR system from Shanghai United-Imaging Healthcare Co. and from GE Healthcare Co. The rib localization algorithm achieved a sensitivity of 98.2% with 0.1 false positives per image. The accuracy of the detected ribs was further evaluated subjectively in 3 levels: "1", good; "2", acceptable; "3", poor. The percentages of good, acceptable, and poor segmentation results were 91.1%, 7.2%, and 1.7%, respectively. Our algorithm can obtain good segmentation results for ribs in chest radiography and would be useful for rib reduction in our future study.

  5. Anomalous hydrodynamics of fractional quantum Hall states

    SciTech Connect

    Wiegmann, P.

    2013-09-15

    We propose a comprehensive framework for quantum hydrodynamics of the fractional quantum Hall (FQH) states. We suggest that the electronic fluid in the FQH regime can be phenomenologically described by the quantized hydrodynamics of vortices in an incompressible rotating liquid. We demonstrate that such hydrodynamics captures all major features of FQH states, including the subtle effect of the Lorentz shear stress. We present a consistent quantization of the hydrodynamics of an incompressible fluid, providing a powerful framework to study the FQH effect and superfluids. We obtain the quantum hydrodynamics of the vortex flow by quantizing the Kirchhoff equations for vortex dynamics.

  6. Inspecting Pipe Radiographically Through Asbestos Insulation

    NASA Technical Reports Server (NTRS)

    Gianettino, David P.

    1994-01-01

    Welds between sections of insulated steampipe located and inspected radiographically. Unless need to repair defective weld, one avoids cost, time, and hazard of removing asbestos insulation. Enables inspectors to locate and evaluate nondestructively any weld in pipe system, without shutting down steam. Hidden weld joints first located by use of low-power fluoroscope, moved along pipe while technician observes fluoroscopic image. Low-energy x rays from fluoroscope penetrate insulation but not pipe. Weld bead appears in silhouette on fluoroscope screen. Technician then accurately marks weld sites on insulation for later inspection.

  7. Hydrodynamic simulations with the Godunov smoothed particle hydrodynamics

    NASA Astrophysics Data System (ADS)

    Murante, G.; Borgani, S.; Brunino, R.; Cha, S.-H.

    2011-10-01

    We present results based on an implementation of the Godunov smoothed particle hydrodynamics (GSPH), originally developed by Inutsuka, in the GADGET-3 hydrodynamic code. We first review the derivation of the GSPH discretization of the equations of moment and energy conservation, starting from the convolution of these equations with the interpolating kernel. The two most important aspects of the numerical implementation of these equations are (a) the appearance of fluid velocity and pressure obtained from the solution of the Riemann problem between each pair of particles, and (b) the absence of an artificial viscosity term. We carry out three different controlled hydrodynamical three-dimensional tests, namely the Sod shock tube, the development of Kelvin-Helmholtz instabilities in a shear-flow test and the 'blob' test describing the evolution of a cold cloud moving against a hot wind. The results of our tests confirm and extend in a number of aspects those recently obtained by Cha, Inutsuka & Nayakshin: (i) GSPH provides a much improved description of contact discontinuities, with respect to smoothed particle hydrodynamics (SPH), thus avoiding the appearance of spurious pressure forces; (ii) GSPH is able to follow the development of gas-dynamical instabilities, such as the Kevin-Helmholtz and the Rayleigh-Taylor ones; (iii) as a result, GSPH describes the development of curl structures in the shear-flow test and the dissolution of the cold cloud in the 'blob' test. Besides comparing the results of GSPH with those from standard SPH implementations, we also discuss in detail the effect on the performances of GSPH of changing different aspects of its implementation: choice of the number of neighbours, accuracy of the interpolation procedure to locate the interface between two fluid elements (particles) for the solution of the Riemann problem, order of the reconstruction for the assignment of variables at the interface, choice of the limiter to prevent oscillations of

  8. Hydrodynamics from Landau initial conditions

    SciTech Connect

    Sen, Abhisek; Gerhard, Jochen; Torrieri, Giorgio; Read jr, Kenneth F.; Wong, Cheuk-Yin

    2015-01-01

    We investigate ideal hydrodynamic evolution, with Landau initial conditions, both in a semi-analytical 1+1D approach and in a numerical code incorporating event-by-event variation with many events and transverse density inhomogeneities. The object of the calculation is to test how fast would a Landau initial condition transition to a commonly used boost-invariant expansion. We show that the transition to boost-invariant flow occurs too late for realistic setups, with corrections of O (20 - 30%) expected at freezeout for most scenarios. Moreover, the deviation from boost-invariance is correlated with both transverse flow and elliptic flow, with the more highly transversely flowing regions also showing the most violation of boost invariance. Therefore, if longitudinal flow is not fully developed at the early stages of heavy ion collisions, 2+1 dimensional hydrodynamics is inadequate to extract transport coefficients of the quark-gluon plasma. Based on [1, 2

  9. Algorithm refinement for fluctuating hydrodynamics

    SciTech Connect

    Williams, Sarah A.; Bell, John B.; Garcia, Alejandro L.

    2007-07-03

    This paper introduces an adaptive mesh and algorithmrefinement method for fluctuating hydrodynamics. This particle-continuumhybrid simulates the dynamics of a compressible fluid with thermalfluctuations. The particle algorithm is direct simulation Monte Carlo(DSMC), a molecular-level scheme based on the Boltzmann equation. Thecontinuum algorithm is based on the Landau-Lifshitz Navier-Stokes (LLNS)equations, which incorporate thermal fluctuations into macroscopichydrodynamics by using stochastic fluxes. It uses a recently-developedsolver for LLNS, based on third-order Runge-Kutta. We present numericaltests of systems in and out of equilibrium, including time-dependentsystems, and demonstrate dynamic adaptive refinement by the computationof a moving shock wave. Mean system behavior and second moment statisticsof our simulations match theoretical values and benchmarks well. We findthat particular attention should be paid to the spectrum of the flux atthe interface between the particle and continuum methods, specificallyfor the non-hydrodynamic (kinetic) time scales.

  10. [Quality of dental radiographs. A sample from 52 general practices].

    PubMed

    Mol, A; Hack, B; van Aken, J; van Straaten, F J; van Foreest, J D

    1989-12-01

    To assess the quality of dental radiographs in general practice, 1000 radiographs in 52 practices were collected and evaluated. The radiographs were judged by two examiners using standard series of X-ray film, showing different degrees of the nine different types of errors studied. Furthermore, the diagnostic quality was assessed; if the diagnostic value was poor, the cause was registered. Only 3.1% of the investigated radiographs met all the criteria, and the quality of 13.4% was found to be poor. The main causes were filmpositioning, density and errors in the category 'residual'. It also appeared that a combination of errors in one radiograph, which were individually not very serious, resulted in an unacceptable radiograph.

  11. Structural damage in rheumatoid arthritis as visualized through radiographs

    PubMed Central

    2002-01-01

    Several agents show an effect on reducing radiographic progression in rheumatoid arthritis. It is tempting to retrospectively compare the effects of these agents on radiographic progression across clinical trials. However, there are several limitations in interpreting and comparing radiographic results across clinical trials. These limitations, including study designs, patient characteristics, durations of follow-up, scoring methodologies, reader reliability, radiograph sequence, handling of missing data, and data presentation, will be discussed. The consequences are illustrated with several examples of recent clinical trials that show an effect on radiographic progression. A guide in the interpretation and clinical relevance of radiographic results is presented, with the Anti-TNF Trial in Rheumatoid Arthritis with Concomitant Therapy used as an example. PMID:12110155

  12. Particle hydrodynamics with tessellation techniques

    NASA Astrophysics Data System (ADS)

    Heß, Steffen; Springel, Volker

    2010-08-01

    Lagrangian smoothed particle hydrodynamics (SPH) is a well-established approach to model fluids in astrophysical problems, thanks to its geometric flexibility and ability to automatically adjust the spatial resolution to the clumping of matter. However, a number of recent studies have emphasized inaccuracies of SPH in the treatment of fluid instabilities. The origin of these numerical problems can be traced back to spurious surface effects across contact discontinuities, and to SPH's inherent prevention of mixing at the particle level. We here investigate a new fluid particle model where the density estimate is carried out with the help of an auxiliary mesh constructed as the Voronoi tessellation of the simulation particles instead of an adaptive smoothing kernel. This Voronoi-based approach improves the ability of the scheme to represent sharp contact discontinuities. We show that this eliminates spurious surface tension effects present in SPH and that play a role in suppressing certain fluid instabilities. We find that the new `Voronoi Particle Hydrodynamics' (VPH) described here produces comparable results to SPH in shocks, and better ones in turbulent regimes of pure hydrodynamical simulations. We also discuss formulations of the artificial viscosity needed in this scheme and how judiciously chosen correction forces can be derived in order to maintain a high degree of particle order and hence a regular Voronoi mesh. This is especially helpful in simulating self-gravitating fluids with existing gravity solvers used for N-body simulations.

  13. The Gulf of Lions' hydrodynamics

    NASA Astrophysics Data System (ADS)

    Millot, Claude

    1990-09-01

    From an hydrodynamical point of view, the Gulf of Lions can be considered as a very complex region, because several intense and highly variable phenomena compete simultaneously. These processes include the powerful general circulation along the continental slope, the formation of dense water both on the shelf and offshore, a seasonal variation of stratification and the extreme energies associated with meteorological conditions. The cloudless atmospheric conditions encountered generally in the northwestern Mediterranean Sea have enabled us to make use of, over more than 10 years, large use of various satellite imageries. The large space and time variability of the hydrodynamical features, a complex topography and a noticeable fishing activity, represent certain difficulties to the collection of observations in situ. We have obtained, therefore, only a few current time series on the slope; those obtained on the shelf only cover the summer period. Models have been elaborated to help us understand the reasons for the general circulation. Observational programmes to be carried out in the forthcoming years will probably provide us with more definitive results on the Gulf of Lions' hydrodynamics.

  14. Diagnostic radiographic findings and symptom-free teeth.

    PubMed

    Selden, H S

    1994-02-01

    The determination of whether a symptom-free tooth has pulpal and periapical disease relies heavily on radiographic findings and pulp tests. A case of a symptom-free upper left first molar is presented. The radiographic evidence of pathological changes associated with the endo-antral syndrome coupled with diffuse pulpal calcifications facilitated the diagnosis of chronic pulpal periapical disease. Non-surgical root canal therapy resulted in periapical healing as shown on a follow-up radiograph. PMID:8006564

  15. [Measurement of bone structure on the radiograph. Utopia or reality?].

    PubMed

    Czerwiński, E

    1996-11-01

    A method of computerised analysis of bone structure assessment using a professional image analyser is described. Analyses of experimental radiographs of human radius taken over a period of time in a standard laboratory were performed. The radiographic technique was ascertained as the main source of a precision error. The reproducibility of the analysis using the method described was found to hold a limited range of error. The program Quantitrab makes possible a quantitative description of the bone structure parameters on the radiograph.

  16. MRI visualisation by digitally reconstructed radiographs

    NASA Astrophysics Data System (ADS)

    Serrurier, Antoine; Bönsch, Andrea; Lau, Robert; Deserno, Thomas M.

    2015-03-01

    Visualising volumetric medical images such as computed tomography and magnetic resonance imaging (MRI) on picture archiving and communication systems (PACS) clients is often achieved by image browsing in sagittal, coronal or axial views or three-dimensional (3D) rendering. This latter technique requires fine thresholding for MRI. On the other hand, computing virtual radiograph images, also referred to as digitally reconstructed radiographs (DRR), provides in a single two-dimensional (2D) image a complete overview of the 3D data. It appears therefore as a powerful alternative for MRI visualisation and preview in PACS. This study describes a method to compute DRR from T1-weighted MRI. After segmentation of the background, a histogram distribution analysis is performed and each foreground MRI voxel is labeled as one of three tissues: cortical bone, also known as principal absorber of the X-rays, muscle and fat. An intensity level is attributed to each voxel according to the Hounsfield scale, linearly related to the X-ray attenuation coefficient. Each DRR pixel is computed as the accumulation of the new intensities of the MRI dataset along the corresponding X-ray. The method has been tested on 16 T1-weighted MRI sets. Anterior-posterior and lateral DRR have been computed with reasonable qualities and avoiding any manual tissue segmentations. This proof-of-concept holds for research application for use in clinical PACS.

  17. Algorithm for dual-energy radiographic analysis

    SciTech Connect

    Morris, R.A.; Chancellor, T.

    1994-12-01

    The use of two or more radiographs of an object taken with different x-ray spectral characteristics to infer quantitative values of material density or Z number has been of interest to both the medical and industrial worlds for some time. One method uses monoenergetic isotopic sources with well defined energies in conjunction with standard step wedges and solving the resulting simultaneous equations. Besides the problem of finding isotopic sources with the appropriate energies, you have to have a priori knowledge of the materials in the object. This paper describes an algorithm that does not impose any limitations on the energy spectrum of the sources nor require any knowledge of the object. The algorithm does require that the different radiographs have perfect spatial registration (within a pixel width) and assumes that the transmitted x-ray intensity spectra is the same (within a multiplicative constant) over the image plane. This paper is just a start in developing multi-energy techniques; objects with three or more materials have not been investigated and it is not clear just how this algorithm should be generalized to the multi-energy case.

  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. 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.

  20. Susuk - black magic exposed "white" by dental radiographs.

    PubMed

    F, Arishiya Thapasum; Mohammed, Faraz

    2014-07-01

    Susuk or charm needles are a facial cum body art widely practiced among women of Malaysia, Brunei, Singapore, Thailand and Indonesia. These are small, needle-shaped metallic talismans inserted subcutaneously in different parts of the body. The concealed art of susuk was "exposed" by routine radiographic examination in the oral and maxillofacial region. This paper reports two such cases of unusual incidental radiographic finding in dental radiographs which were taken on a routine basis as part of the diagnostic work up. This article will also primarily enlighten the importance of radiographs in detecting such charm needles as the wearer keeps the body art a "hidden secret" thereby avoiding misdiagnosis. PMID:25177646

  1. Computer Analysis Of ILO Standard Chest Radiographs Of Pneumoconiosis

    NASA Astrophysics Data System (ADS)

    Li, C. C.; Shu, David B. C.; Tai, H. T.; Hou, W.; Kunkle, G. A.; Wang, Y.; Hoy, R. J.

    1982-11-01

    This paper presents study of computer analysis of the 1980 ILO standard chest radiographs of pneumoconiosis. Algorithms developed for detection of individual small rounded and irregular opacities have been experimented and evaluated on these standard radiographs. The density, shape, and size distribution of the detected objects in the lung field, in spite of false positives, can be used as indicators for the beginning of pneumoconiosis. This approach is potentially useful in computer-assisted screening and early detection process where the annual chest radiograph of each worker is compared with his (her) own normal radiograph obtained previously.

  2. 2-D LSP Simulations of the Self Magnetic Pinch Radiographic Diode

    NASA Astrophysics Data System (ADS)

    Threadgold, J.; Crotch, I.; Rose, D. V.

    2003-10-01

    The Atomic Weapons Establishment (AWE) UK has a number of Pulsed Power driven flash X-ray machines which are used to take transmission radiographs of hydrodynamic experiments. Some of the lower voltage x-ray machines (< 2 MV) use the Self Magnetic (SM) Pinch diode for their source. The SM pinch diode has proved to be a reliable source for providing small diameter radiographic spot sizes. With an emphasis on reduction of the x-ray spot size at higher voltages, one part of the diode research project has been to field SM pinch diodes at higher voltages. The SM pinch diode relies upon the magnitude of its own electron current (> 50 kA) to pinch the electron beam to a small diameter onto a high Z converter target. An electromagnetic PIC code, LSP, has been used to carry out 2-D simulations of the diode to support this project. The code has been used to investigate the effect of different target materials within the diode and to investigate the resultant electron trajectories onto the target. Results of these code simulations will be compared to experimental data The simulations show good agreement with measured experimental data on diode performance. The simulations suggest further improvements in spot size reduction could be achieved with changes in the diode geometry.

  3. Endocrine changes in histiocytosis of the hypothalamic-pituitary axis.

    PubMed

    Toro Galván, Silvia; Planas Vilaseca, Alejandra; Michalopoulou Alevras, Theodora; Torres Díaz, Alberto; Suárez Balaguer, Javier; Villabona Artero, Carles

    2015-02-01

    Histiocytosis is characterized by proliferation of cells from the mononuclear phagocyte system, and may be divided into Langerhans cell histiocytosis (LCH) and non-Langerhans cell histiocytosis (including Erdheim-Chester disease [ECD]). While diabetes insipidus (DI) is the most common hypothalamic-pituitary consequence, anterior pituitary deficiencies are less known. This study analyzed the frequency and progression of pituitary hormone deficiencies and the radiographic findings in 9 patients (7 with LCH and 2 with ECD) with hypothalamic-pituitary (HP) axis. Eighty-nine percent of patients had DI (62% at diagnosis), and 78% had one or more anterior pituitary deficiencies (71% at diagnosis). HP involvement is relatively common in patients diagnosed with histiocytosis and hormone deficiencies may be present at diagnosis or appear gradually during the course of disease. Regular monitoring of these patients is recommended.

  4. Magnetic axis safety factor of finite β spheromaks and transition from spheromaks to toroidal magnetic bubbles

    SciTech Connect

    Bellan, Paul M.; Paccagnella, Roberto

    2015-02-15

    The value of the safety factor on the magnetic axis of a finite-beta spheromak is shown to be a function of beta in contrast to what was used in Bellan, Phys. Plasmas 9, 3050 (2002); this dependence on beta substantially reduces the gradient of the safety factor compared to the previous calculation. The method for generating finite-beta spheromak equilibria is extended to generate equilibria describing toroidal magnetic “bubbles,” where the hydrodynamic pressure on the magnetic axis is less than on the toroid surface. This “anti-confinement” configuration can be considered an equilibrium with an inverted beta profile and is relevant to interplanetary magnetic clouds as these clouds have lower hydrodynamic pressure in their interior than on their surface.

  5. Vertical axis wind turbine airfoil

    DOEpatents

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

    2012-12-18

    A vertical axis wind turbine airfoil is described. The wind turbine airfoil can include a leading edge, a trailing edge, an upper curved surface, a lower curved surface, and a centerline running between the upper surface and the lower surface and from the leading edge to the trailing edge. The airfoil can be configured so that the distance between the centerline and the upper surface is the same as the distance between the centerline and the lower surface at all points along the length of the airfoil. A plurality of such airfoils can be included in a vertical axis wind turbine. These airfoils can be vertically disposed and can rotate about a vertical axis.

  6. HEMP. Hydrodynamic Elastic Magneto Plastic

    SciTech Connect

    Wilkins, M.L.; Levatin, J.A.

    1985-02-01

    The HEMP code solves the conservation equations of two-dimensional elastic-plastic flow, in plane x-y coordinates or in cylindrical symmetry around the x-axis. Provisions for calculation of fixed boundaries, free surfaces, pistons, and boundary slide planes have been included, along with other special conditions.

  7. The radiographic union scale in tibial (RUST) fractures

    PubMed Central

    Clement, N. D.; Tawonsawatruk, T.; Simpson, C. J.; Simpson, A. H. R. W.

    2016-01-01

    Objectives The radiographic union score for tibial (RUST) fractures was developed by Whelan et al to assess the healing of tibial fractures following intramedullary nailing. In the current study, the repeatability and reliability of the RUST score was evaluated in an independent centre (a) using the original description, (b) after further interpretation of the description of the score, and (c) with the immediate post-operative radiograph available for comparison. Methods A total of 15 radiographs of tibial shaft fractures treated by intramedullary nailing (IM) were scored by three observers using the RUST system. Following discussion on how the criteria of the RUST system should be implemented, 45 sets (i.e. AP and lateral) of radiographs of IM nailed tibial fractures were scored by five observers. Finally, these 45 sets of radiographs were rescored with the baseline post-operative radiograph available for comparison. Results The initial intraclass correlation (ICC) on the first 15 sets of radiographs was 0.67 (95% CI 0.63 to 0.71). However, the original description was being interpreted in different ways. After agreeing on the interpretation, the ICC on the second cohort improved to 0.75. The ICC improved even further to 0.79, when the baseline post-operative radiographs were available for comparison. Conclusion This study demonstrates that the RUST scoring system is a reliable and repeatable outcome measure for assessing tibial fracture healing. Further improvement in the reliability of the scoring system can be obtained if the radiographs are compared with the baseline post-operative radiographs. Cite this article: Mr J.M. Leow. The radiographic union scale in tibial (RUST) fractures: Reliability of the outcome measure at an independent centre. Bone Joint Res 2016;5:116–121. DOI: 10.1302/2046-3758.54.2000628. PMID:27073210

  8. Gut Microbiota-brain Axis

    PubMed Central

    Wang, Hong-Xing; Wang, Yu-Ping

    2016-01-01

    Objective: To systematically review the updated information about the gut microbiota-brain axis. Data Sources: All articles about gut microbiota-brain axis published up to July 18, 2016, were identified through a literature search on PubMed, ScienceDirect, and Web of Science, with the keywords of “gut microbiota”, “gut-brain axis”, and “neuroscience”. Study Selection: All relevant articles on gut microbiota and gut-brain axis were included and carefully reviewed, with no limitation of study design. Results: It is well-recognized that gut microbiota affects the brain's physiological, behavioral, and cognitive functions although its precise mechanism has not yet been fully understood. Gut microbiota-brain axis may include gut microbiota and their metabolic products, enteric nervous system, sympathetic and parasympathetic branches within the autonomic nervous system, neural-immune system, neuroendocrine system, and central nervous system. Moreover, there may be five communication routes between gut microbiota and brain, including the gut-brain's neural network, neuroendocrine-hypothalamic-pituitary-adrenal axis, gut immune system, some neurotransmitters and neural regulators synthesized by gut bacteria, and barrier paths including intestinal mucosal barrier and blood-brain barrier. The microbiome is used to define the composition and functional characteristics of gut microbiota, and metagenomics is an appropriate technique to characterize gut microbiota. Conclusions: Gut microbiota-brain axis refers to a bidirectional information network between the gut microbiota and the brain, which may provide a new way to protect the brain in the near future. PMID:27647198

  9. Assessment of primary hip osteoarthritis: comparison of radiographic methods using colon radiographs

    PubMed Central

    Ingvarsson, T.; Hagglund, G.; Lindberg, H.; Lohmander, L

    2000-01-01

    OBJECTIVE—To compare the reliability of quantitative measurement of minimum hip joint space with a qualitative global assessment of radiological features for estimating the prevalence of primary osteoarthritis (OA) of the hip in colon radiographs.
METHODS—All colon radiographs from patients aged 35 or older, taken at three different radiographic departments in Iceland during the years 1990-96, were examined. A total of 3002 hips in 638 men and 863 women were analysed. Intraobserver and interobserver reliability was assessed by measuring 147 randomly selected radiographs (294 hips) twice by the same observer, and 87 and 98 randomly selected radiographs (174 and 196 hips) by two additional independent observers. Minimum hip joint space was measured with a millimetre ruler, and global assessment of radiological features by a published atlas.
RESULTS—With a minimum joint space of 2.5 mm or less as definition for OA, 212 hips were defined as having OA. When the global Kellgren and Lawrence assessment with grade 2 (definite narrowing in the presence of definite osteophytes) or higher as definition for OA was used, 202 hips showed OA. However, only 166 hips were diagnosed as OA with both systems. With 2.0 or 3.0 mm minimum joint space as cut off point, the difference between the two methods increased. Both intrarater and interrater reliability was significantly higher with joint space measurement than with global assessment.
CONCLUSIONS—Overall prevalence of radiological OA was similar with the two methods. However, the quantitative measurement of minimum hip joint space had a better within-observer and between-observer reliability than qualitative global assessment of radiographic features of hip OA. It is thus suggested that minimum joint space measurement is a preferable method in epidemiological studies of radiological hip OA.

 PMID:10913065

  10. Two-axis angular effector

    DOEpatents

    Vaughn, Mark R.; Robinett, III, Rush D.; Phelan, John R.; Van Zuiden, Don M.

    1997-01-21

    A new class of coplanar two-axis angular effectors. These effectors combine a two-axis rotational joint analogous to a Cardan joint with linear actuators in a manner to produce a wider range of rotational motion about both axes defined by the joint. This new class of effectors also allows design of robotic manipulators having very high strength and efficiency. These effectors are particularly suited for remote operation in unknown surroundings, because of their extraordinary versatility. An immediate application is to the problems which arise in nuclear waste remediation.

  11. Forced wetting and hydrodynamic assist

    NASA Astrophysics Data System (ADS)

    Blake, Terence D.; Fernandez-Toledano, Juan-Carlos; Doyen, Guillaume; De Coninck, Joël

    2015-11-01

    Wetting is a prerequisite for coating a uniform layer of liquid onto a solid. Wetting failure and air entrainment set the ultimate limit to coating speed. It is well known in the coating art that this limit can be postponed by manipulating the coating flow to generate what has been termed "hydrodynamic assist," but the underlying mechanism is unclear. Experiments have shown that the conditions that postpone air entrainment also reduce the apparent dynamic contact angle, suggesting a direct link, but how the flow might affect the contact angle remains to be established. Here, we use molecular dynamics to compare the outcome of steady forced wetting with previous results for the spontaneous spreading of liquid drops and apply the molecular-kinetic theory of dynamic wetting to rationalize our findings and place them on a quantitative footing. The forced wetting simulations reveal significant slip at the solid-liquid interface and details of the flow immediately adjacent to the moving contact line. Our results confirm that the local, microscopic contact angle is dependent not simply only on the velocity of wetting but also on the nature of the flow that drives it. In particular, they support an earlier suggestion that during forced wetting, an intense shear stress in the vicinity of the contact line can assist surface tension forces in promoting dynamic wetting, thus reducing the velocity-dependence of the contact angle. Hydrodynamic assist then appears as a natural consequence of wetting that emerges when the contact line is driven by a strong and highly confined flow. Our theoretical approach also provides a self-consistent model of molecular slip at the solid-liquid interface that enables its magnitude to be estimated from dynamic contact angle measurements. In addition, the model predicts how hydrodynamic assist and slip may be influenced by liquid viscosity and solid-liquid interactions.

  12. Model-based segmentation of hand radiographs

    NASA Astrophysics Data System (ADS)

    Weiler, Frank; Vogelsang, Frank

    1998-06-01

    An important procedure in pediatrics is to determine the skeletal maturity of a patient from radiographs of the hand. There is great interest in the automation of this tedious and time-consuming task. We present a new method for the segmentation of the bones of the hand, which allows the assessment of the skeletal maturity with an appropriate database of reference bones, similar to the atlas based methods. The proposed algorithm uses an extended active contour model for the segmentation of the hand bones, which incorporates a-priori knowledge of shape and topology of the bones in an additional energy term. This `scene knowledge' is integrated in a complex hierarchical image model, that is used for the image analysis task.

  13. Recovery of silver from radiographic fixer.

    PubMed

    Goshima, T; Hori, K; Yamamoto, A

    1994-06-01

    This study examined the silver content of 10 brands of dental x-ray film that are commercially available in Japan. Kodak Ektaspeed EP-22 (Eastman Kodak Co., Rochester, N.Y.) was found to have the highest silver content, and SD 100 Gold X-ray Film (San Dental Co., Ltd., Tokyo, Japan) had the lowest content of silver. Electrolysis and ion exchange were used as the methods of silver recovery from films in the general dental office. Ion exchange was more than 99% efficient in silver recovery from the radiographic fixer and resulted in an 80% reduction in biochemical oxygen demand and a 95% reduction in chemical oxygen demand. However, these levels and other environmental pollutants were still above the limits set by the Japanese Pollutant Control law. PMID:8065739

  14. Radiographic apparatus for photographing entire jaws

    SciTech Connect

    Nakano, K.

    1985-01-22

    This disclosure relates to a dental radiographic apparatus for photographing the entire jaw designed to control the rotation of a rotary arm such that the film surface of a film holder mounted at one end of the rotary arm may rotate and move substantially at equal speed substantially equidistantly along the dental arch and that the X-ray beams irradiated upon the film surface from an X-ray generator mounted at the other end of the arm may fall on the dental arch at any point thereof at right angles with the arch. The apparatus makes it possible to obtain a very clear tomographic picture of a curved plane of the entire jaws, the picture being free of a double image of the teeth, partial change in enlargement ratio of the image obtained, and partial difference in the shade of the image obtained.

  15. Evaluation of the quality of duplicated radiographs

    SciTech Connect

    Thunthy, K.H.; Weinberg, R.

    1981-04-01

    This experiment evaluated the image quality of duplicated radiographs made at different ultraviolet light exposures. Image quality was measured in terms of ''residual'' film fog, film density, mottle, image contrast, and resolution. The ''residual'' fog density of duplicates decreased with increases in ultraviolet exposures until it was less than the fog density of the original. The density of duplicates decreased with increases in ultraviolet exposures until it leveled off at a certain density, depending on the density of the original film. Mottle was less on lighter duplicates than on darker duplicates. Contrast of duplicates increased initially with increases in ultraviolet exposures and later decreased with further increases in ultraviolet exposures. Resolution of duplicates was nearly the same as the original as long as the duplicate had acceptable ''residual'' fog density.

  16. Temporal stability of digital radiographic detectors.

    PubMed

    Ireland, Timothy A; Irvine, Mike

    2016-03-01

    With the current preference for digital radiographic detectors in modern radiology facilities, there has been increasing demand for baseline technical data for equipment comparison and benchmarking. Key system parameters were monitored in 12 individual digital detectors over a 6 months period following installation, to establish baseline performance fluctuations for current generation indirect digital detectors. Performance criteria monitored included exposure index consistency, detector uniformity, system transfer function, artifact presentation, automatic exposure control reproducibility and dose area product consistency. Two indirect digital detector models were included, with the final set of measurements for each detector taken after routine detector calibrations were completed by technical staff. Suggested performance limits are presented based on observed temporal fluctuations, as well as national and international standards, where applicable.

  17. Disruptive Innovation in Numerical Hydrodynamics

    SciTech Connect

    Waltz, Jacob I.

    2012-09-06

    We propose the research and development of a high-fidelity hydrodynamic algorithm for tetrahedral meshes that will lead to a disruptive innovation in the numerical modeling of Laboratory problems. Our proposed innovation has the potential to reduce turnaround time by orders of magnitude relative to Advanced Simulation and Computing (ASC) codes; reduce simulation setup costs by millions of dollars per year; and effectively leverage Graphics Processing Unit (GPU) and future Exascale computing hardware. If successful, this work will lead to a dramatic leap forward in the Laboratory's quest for a predictive simulation capability.

  18. Hydrodynamic Synchronisation of Model Microswimmers

    NASA Astrophysics Data System (ADS)

    Putz, V. B.; Yeomans, J. M.

    2009-12-01

    We define a model microswimmer with a variable cycle time, thus allowing the possibility of phase locking driven by hydrodynamic interactions between swimmers. We find that, for extensile or contractile swimmers, phase locking does occur, with the relative phase of the two swimmers being, in general, close to 0 or π, depending on their relative position and orientation. We show that, as expected on grounds of symmetry, self T-dual swimmers, which are time-reversal covariant, do not phase-lock. We also discuss the phase behaviour of a line of tethered swimmers, or pumps. These show oscillations in their relative phases reminiscent of the metachronal waves of cilia.

  19. Ergoregion instability: The hydrodynamic vortex

    NASA Astrophysics Data System (ADS)

    Oliveira, Leandro A.; Cardoso, Vitor; Crispino, Luís C. B.

    2014-06-01

    Four-dimensional, asymptotically flat spacetimes with an ergoregion but no horizon have been shown to be linearly unstable against a superradiant-triggered mechanism. This result has wide implications in the search for astrophysically viable alternatives to black holes, but also in the understanding of black holes and Hawking evaporation. Here we investigate this instability in detail for a particular setup that can be realized in the laboratory: the hydrodynamic vortex, an effective geometry for sound waves, with ergoregion and without an event horizon.

  20. Hydrodynamic instability modeling for ICF

    SciTech Connect

    Haan, S.W.

    1993-03-31

    The intent of this paper is to review how instability growth is modeled in ICF targets, and to identify the principal issues. Most of the material has been published previously, but is not familiar to a wide audience. Hydrodynamic instabilities are a key issue in ICF. Along with laser-plasma instabilities, they determine the regime in which ignition is possible. At higher laser energies, the same issues determine the achievable gain. Quantitative predictions are therefore of the utmost importance to planning the ICF program, as well as to understanding current Nova results. The key fact that underlies all this work is the stabilization of short wavelengths.

  1. Effective actions for anomalous hydrodynamics

    NASA Astrophysics Data System (ADS)

    Haehl, Felix M.; Loganayagam, R.; Rangamani, Mukund

    2014-03-01

    We argue that an effective field theory of local fluid elements captures the constraints on hydrodynamic transport stemming from the presence of quantum anomalies in the underlying microscopic theory. Focussing on global current anomalies for an arbitrary flavour group, we derive the anomalous constitutive relations in arbitrary even dimensions. We demonstrate that our results agree with the constraints on anomaly governed transport derived hitherto using a local version of the second law of thermodynamics. The construction crucially uses the anomaly inflow mechanism and involves a novel thermofield double construction. In particular, we show that the anomalous Ward identities necessitate non-trivial interaction between the two parts of the Schwinger-Keldysh contour.

  2. Hydrodynamic loading of tensegrity structures

    NASA Astrophysics Data System (ADS)

    Wroldsen, Anders S.; Johansen, Vegar; Skelton, Robert E.; Sørensen, Asgeir J.

    2006-03-01

    This paper introduces hydrodynamic loads for tensegrity structures, to examine their behavior in marine environments. Wave compliant structures are of general interest when considering large marine structures, and we are motivated by the aquaculture industry where new concepts are investigated in order to make offshore installations for seafood production. This paper adds to the existing models and software simulations of tensegrity structures exposed to environmental loading from waves and current. A number of simulations are run to show behavior of the structure as a function of pretension level and string stiffness for a given loading condition.

  3. Progress in smooth particle hydrodynamics

    SciTech Connect

    Wingate, C.A.; Dilts, G.A.; Mandell, D.A.; Crotzer, L.A.; Knapp, C.E.

    1998-07-01

    Smooth Particle Hydrodynamics (SPH) is a meshless, Lagrangian numerical method for hydrodynamics calculations where calculational elements are fuzzy particles which move according to the hydrodynamic equations of motion. Each particle carries local values of density, temperature, pressure and other hydrodynamic parameters. A major advantage of SPH is that it is meshless, thus large deformation calculations can be easily done with no connectivity complications. Interface positions are known and there are no problems with advecting quantities through a mesh that typical Eulerian codes have. These underlying SPH features make fracture physics easy and natural and in fact, much of the applications work revolves around simulating fracture. Debris particles from impacts can be easily transported across large voids with SPH. While SPH has considerable promise, there are some problems inherent in the technique that have so far limited its usefulness. The most serious problem is the well known instability in tension leading to particle clumping and numerical fracture. Another problem is that the SPH interpolation is only correct when particles are uniformly spaced a half particle apart leading to incorrect strain rates, accelerations and other quantities for general particle distributions. SPH calculations are also sensitive to particle locations. The standard artificial viscosity treatment in SPH leads to spurious viscosity in shear flows. This paper will demonstrate solutions for these problems that they and others have been developing. The most promising is to replace the SPH interpolant with the moving least squares (MLS) interpolant invented by Lancaster and Salkauskas in 1981. SPH and MLS are closely related with MLS being essentially SPH with corrected particle volumes. When formulated correctly, JLS is conservative, stable in both compression and tension, does not have the SPH boundary problems and is not sensitive to particle placement. The other approach to

  4. Hydrodynamical models of young SNRs.

    NASA Astrophysics Data System (ADS)

    Kosenko, D. I.; Blinnikov, S. I.; Postnov, K. A.; Sorokina, E. I.

    X-ray observations of the Tycho supernova (SN) remnant by XMM-Newton telescope present radial profiles of the remnant in emission lines from silicon and iron \\citep{decour}. To reproduce observed spectrum and X-ray profiles hydrodynamical modelling of the remnant was performed by \\citet{elka}. Standard computational SN models cannot reproduce observed spacial behavoir of the X-ray profiles of the remnant in the emission lines. We perform analysis of these numerical models and find conditions under which it is possible to reproduce observed profiles.

  5. Dental biometrics: alignment and matching of dental radiographs.

    PubMed

    Chen, Hong; Jain, Anil K

    2005-08-01

    Dental biometrics utilizes dental radiographs for human identification. The dental radiographs provide information about teeth, including tooth contours, elative positions of neighboring teeth, and shapes of the dental work (e.g., crowns, fillings, and bridges). The proposed system has two main stages: feature extraction and matching. The feature extraction stage uses anisotropic diffusion to enhance the images and a Mixture of Gaussians model to segment the dental work. The matching stage has three sequential steps: tooth-level matching, computation of image distances, and subject identification. In the tooth-level matching step, tooth contours are matched using a shape registration method, and the dental work is matched on overlapping areas. The distance between the tooth contours and the distance between the dental work are then combined using posterior probabilities. In the second step, the tooth correspondences between the given query (postmortem) radiograph and the database (antemortem) radiograph are established. A distance based on the corresponding teeth is then used to measure the similarity between the two radiographs. Finally, all the distances between the given postmortem radiographs and the antemortem radiographs that provide candidate identities are combined to establish the identity of the subject associated with the postmortem radiographs.

  6. 10 CFR 34.41 - Conducting industrial radiographic operations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Conducting industrial radiographic operations. 34.41 Section 34.41 Energy NUCLEAR REGULATORY COMMISSION LICENSES FOR INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Radiation Safety Requirements §...

  7. 10 CFR 34.41 - Conducting industrial radiographic operations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Conducting industrial radiographic operations. 34.41 Section 34.41 Energy NUCLEAR REGULATORY COMMISSION LICENSES FOR INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Radiation Safety Requirements §...

  8. 10 CFR 34.41 - Conducting industrial radiographic operations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Conducting industrial radiographic operations. 34.41 Section 34.41 Energy NUCLEAR REGULATORY COMMISSION LICENSES FOR INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Radiation Safety Requirements §...

  9. 10 CFR 34.41 - Conducting industrial radiographic operations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Conducting industrial radiographic operations. 34.41 Section 34.41 Energy NUCLEAR REGULATORY COMMISSION LICENSES FOR INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Radiation Safety Requirements §...

  10. 10 CFR 34.41 - Conducting industrial radiographic operations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Conducting industrial radiographic operations. 34.41 Section 34.41 Energy NUCLEAR REGULATORY COMMISSION LICENSES FOR INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Radiation Safety Requirements §...

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

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Supervision of radiographers' assistants. 34.46 Section 34.46 Energy NUCLEAR REGULATORY COMMISSION LICENSES FOR INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Radiation Safety Requirements § 34.46 Supervision...

  12. 21 CFR 892.1950 - Radiographic anthropomorphic phantom.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic anthropomorphic phantom. 892.1950 Section 892.1950 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... purposes to simulate a human body for positioning radiographic equipment. (b) Classification. Class...

  13. A Study of Radiographic Imaging Systems Used for Dental Hygiene.

    ERIC Educational Resources Information Center

    Karst, Nancy S.

    Thirty-three two-year dental hygiene programs throughout the United States were surveyed to identify the radiographic imaging system most often used and the accompanying rationale for that decision. A literature review identified the three radiographic imaging systems most frequently used and indicated that all dental hygiene programs had the…

  14. 21 CFR 892.1970 - Radiographic ECG/respirator synchronizer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Radiographic ECG/respirator synchronizer. 892.1970 Section 892.1970 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1970 Radiographic...

  15. 21 CFR 892.1900 - Automatic radiographic film processor.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Automatic radiographic film processor. 892.1900 Section 892.1900 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1900 Automatic radiographic...

  16. 21 CFR 892.1640 - Radiographic film marking system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Radiographic film marking system. 892.1640 Section 892.1640 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1640 Radiographic film marking...

  17. 21 CFR 892.1890 - Radiographic film illuminator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Radiographic film illuminator. 892.1890 Section 892.1890 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1890 Radiographic film illuminator....

  18. 21 CFR 892.1890 - Radiographic film illuminator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Radiographic film illuminator. 892.1890 Section 892.1890 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1890 Radiographic film illuminator....

  19. 21 CFR 892.1950 - Radiographic anthropomorphic phantom.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Radiographic anthropomorphic phantom. 892.1950 Section 892.1950 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1950 Radiographic...

  20. 21 CFR 892.1970 - Radiographic ECG/respirator synchronizer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Radiographic ECG/respirator synchronizer. 892.1970 Section 892.1970 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1970 Radiographic...

  1. 21 CFR 892.1900 - Automatic radiographic film processor.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Automatic radiographic film processor. 892.1900 Section 892.1900 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1900 Automatic radiographic...

  2. 21 CFR 892.1860 - Radiographic film/cassette changer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Radiographic film/cassette changer. 892.1860 Section 892.1860 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1860 Radiographic...

  3. 21 CFR 892.1900 - Automatic radiographic film processor.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Automatic radiographic film processor. 892.1900 Section 892.1900 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1900 Automatic radiographic...

  4. 21 CFR 892.1640 - Radiographic film marking system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Radiographic film marking system. 892.1640 Section 892.1640 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1640 Radiographic film marking...

  5. 21 CFR 892.1950 - Radiographic anthropomorphic phantom.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Radiographic anthropomorphic phantom. 892.1950 Section 892.1950 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1950 Radiographic...

  6. 21 CFR 892.1640 - Radiographic film marking system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Radiographic film marking system. 892.1640 Section 892.1640 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1640 Radiographic film marking...

  7. 21 CFR 892.1860 - Radiographic film/cassette changer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Radiographic film/cassette changer. 892.1860 Section 892.1860 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1860 Radiographic...

  8. 21 CFR 892.1970 - Radiographic ECG/respirator synchronizer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Radiographic ECG/respirator synchronizer. 892.1970 Section 892.1970 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1970 Radiographic...

  9. 21 CFR 892.1860 - Radiographic film/cassette changer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Radiographic film/cassette changer. 892.1860 Section 892.1860 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1860 Radiographic...

  10. 21 CFR 892.1890 - Radiographic film illuminator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Radiographic film illuminator. 892.1890 Section 892.1890 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1890 Radiographic film illuminator....

  11. 21 CFR 892.1960 - Radiographic intensifying screen.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    .... (a) Identification. A radiographic intensifying screen is a device that is a thin radiolucent sheet coated with a luminescent material that transforms incident x-ray photons into visible light and intended for medical purposes to expose radiographic film. (b) Classification. Class I (general controls)....

  12. 21 CFR 892.1960 - Radiographic intensifying screen.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .... (a) Identification. A radiographic intensifying screen is a device that is a thin radiolucent sheet coated with a luminescent material that transforms incident x-ray photons into visible light and intended for medical purposes to expose radiographic film. (b) Classification. Class I (general controls)....

  13. 21 CFR 892.1960 - Radiographic intensifying screen.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    .... (a) Identification. A radiographic intensifying screen is a device that is a thin radiolucent sheet coated with a luminescent material that transforms incident x-ray photons into visible light and intended for medical purposes to expose radiographic film. (b) Classification. Class I (general controls)....

  14. 21 CFR 892.1960 - Radiographic intensifying screen.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .... (a) Identification. A radiographic intensifying screen is a device that is a thin radiolucent sheet coated with a luminescent material that transforms incident x-ray photons into visible light and intended for medical purposes to expose radiographic film. (b) Classification. Class I (general controls)....

  15. 21 CFR 892.1960 - Radiographic intensifying screen.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    .... (a) Identification. A radiographic intensifying screen is a device that is a thin radiolucent sheet coated with a luminescent material that transforms incident x-ray photons into visible light and intended for medical purposes to expose radiographic film. (b) Classification. Class I (general controls)....

  16. Video enhancement of X-ray and neutron radiographs

    NASA Technical Reports Server (NTRS)

    Vary, A.

    1973-01-01

    System was devised for displaying radiographs on television screen and enhancing fine detail in picture. System uses analog-computer circuits to process television signal from low-noise television camera. Enhanced images are displayed in black and white and can be controlled to vary degree of enhancement and magnification of details in either radiographic transparencies or opaque photographs.

  17. Microscale hydrodynamics near moving contact lines

    NASA Technical Reports Server (NTRS)

    Garoff, Stephen; Chen, Q.; Rame, Enrique; Willson, K. R.

    1994-01-01

    The hydrodynamics governing the fluid motions on a microscopic scale near moving contact lines are different from those governing motion far from the contact line. We explore these unique hydrodynamics by detailed measurement of the shape of a fluid meniscus very close to a moving contact line. The validity of present models of the hydrodynamics near moving contact lines as well as the dynamic wetting characteristics of a family of polymer liquids are discussed.

  18. Thermal transport in a noncommutative hydrodynamics

    SciTech Connect

    Geracie, M. Son, D. T.

    2015-03-15

    We find the hydrodynamic equations of a system of particles constrained to be in the lowest Landau level. We interpret the hydrodynamic theory as a Hamiltonian system with the Poisson brackets between the hydrodynamic variables determined from the noncommutativity of space. We argue that the most general hydrodynamic theory can be obtained from this Hamiltonian system by allowing the Righi-Leduc coefficient to be an arbitrary function of thermodynamic variables. We compute the Righi-Leduc coefficient at high temperatures and show that it satisfies the requirements of particle-hole symmetry, which we outline.

  19. Anatomical study of the gastrointestinal tract in free-living axis deer (Axis axis).

    PubMed

    Pérez, W; Erdogan, S; Ungerfeld, R

    2015-02-01

    The macroscopic anatomy of the stomach and intestines of adult axis deer (Axis axis), a cervid species considered intermediate/mixed feeder, was observed and recorded. Nine adult wild axis deers of both sexes were used and studied by simple dissection. The ruminal papillae were distributed unevenly in the overall area of the inner surface of rumen and primarily were more large and abundant within the atrium. The ruminal pillars had no papillae. There was an additional ruminal pillar located between the right longitudinal and right coronary ventral pillars connected to the caudal pillar. No dorsal coronary pillars were found, and the ventral coronary pillars are connected. The reticulum was the third compartment in size, and the maximum height of the reticular crests was 1.0 mm. The Cellulae reticuli were not divided and rarely contained secondary crests. There were no Papillae unguiculiformes. The omasum was the smallest gastric compartment. The abomasum had about twelve spiral plicae, and a small pyloric torus was present. The intraruminal papillation was similar to those species that are characterized by a higher proportion of grass in their natural diet. The finding of the small reticular crests is typical for browser ruminants and was coincident with data reported for other deer. The comparative ratio of the small intestine to the large intestine was 1.69, in terms of length measurements in axis deer and appears below of the 'browser range'. We concluded that the gastrointestinal system of axis deer reflected similar morphological characteristics of the both types of ruminants: browser and grazer, and we consider it as an intermediate feeder.

  20. Three axis velocity probe system

    DOEpatents

    Fasching, George E.; Smith, Jr., Nelson S.; Utt, Carroll E.

    1992-01-01

    A three-axis velocity probe system for determining three-axis positional velocities of small particles in fluidized bed systems and similar applications. This system has a sensor head containing four closely-spaced sensing electrodes of small wires that have flat ends to establish a two axis plane, e.g. a X-Y plane. Two of the sensing electrodes are positioned along one of the axes and the other two are along the second axis. These four sensing electrodes are surrounded by a guard electrode, and the outer surface is a ground electrode and support member for the sensing head. The electrodes are excited by, for example, sinusoidal voltage having a peak-to-peak voltage of up to 500 volts at a frequency of 2 MHz. Capacitive currents flowing between the four sensing electrodes and the ground electrode are influenced by the presence and position of a particle passing the sensing head. Any changes in these currents due to the particle are amplified and synchronously detected to produce positional signal values that are converted to digital form. Using these digital forms and two values of time permit generation of values of the three components of the particle vector and thus the total velocity vector.

  1. Radiographic Parameters in Adult Degenerative Scoliosis and Different Parameters Between Sagittal Balanced and Imbalanced ADS Patients.

    PubMed

    Yang, Changwei; Yang, Mingyuan; Chen, Yuanyuan; Wei, Xianzhao; Ni, Haijian; Chen, Ziqiang; Li, Jingfeng; Bai, Yushu; Zhu, Xiaodong; Li, Ming

    2015-07-01

    A retrospective study. To summarize and describe the radiographic parameters of adult degenerative scoliosis (ADS) and explore the radiological parameters which are significantly different in sagittal balanced and imbalanced ADS patients. ADS is the most common type of adult spinal deformity. However, no comprehensive description of radiographic parameters in ADS patients has been made, and few studies have been performed to explore which radiological parameters are significantly different between sagittal balanced and imbalanced ADS patients. Medical records of ADS patients in our outpatient clinic from January 2012 to January 2014 were reviewed. Demographic data including age and sex, and radiographic data including the coronal Cobb angle, location of apical vertebra/disc, convexity of the curve, degree of apical vertebra rotation, curve segments, thoracic kyphosis (TK), lumbar lordosis (LL), thoracolumbar kyphosis (TL), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), sagittal vertical axis (SVA), and PI minus LL (PI-LL) were reviewed to make comprehensive description of radiographic parameters of ADS. Furthermore, patients were divided into 2 groups according to whether the patients' sagittal plane was balanced: Group A (imbalanced, SVA > 5 cm) and Group B (balanced, SVA  ≤ 5 cm). Demographic and radiological parameters were compared between these 2 groups. A total of 99 patients were included in this study (Group A = 33 and Group B = 66; female = 83 and male = 16; sex ratio = 5:1). The median of age were 67 years (range: 41-92 years). The median of coronal Cobb angle and length of curve was 23 (range: 10-75°) and 5 segments (range: 3-7), respectively. The most common location of apical vertebra was at L2 to L3 (81%) and the median of degree of apical vertebra rotation was 2° (range: 1-3). Our study also showed significant correlations between coronal Cobb angle and curve segments (r = 0.23, P < 0.005) and degree of apical vertebra rotation (r

  2. Active and driven hydrodynamic crystals.

    PubMed

    Desreumaux, N; Florent, N; Lauga, E; Bartolo, D

    2012-08-01

    Motivated by the experimental ability to produce monodisperse particles in microfluidic devices, we study theoretically the hydrodynamic stability of driven and active crystals. We first recall the theoretical tools allowing to quantify the dynamics of elongated particles in a confined fluid. In this regime hydrodynamic interactions between particles arise from a superposition of potential dipolar singularities. We exploit this feature to derive the equations of motion for the particle positions and orientations. After showing that all five planar Bravais lattices are stationary solutions of the equations of motion, we consider separately the case where the particles are passively driven by an external force, and the situation where they are self-propelling. We first demonstrate that phonon modes propagate in driven crystals, which are always marginally stable. The spatial structures of the eigenmodes depend solely on the symmetries of the lattices, and on the orientation of the driving force. For active crystals, the stability of the particle positions and orientations depends not only on the symmetry of the crystals but also on the perturbation wavelengths and on the crystal density. Unlike unconfined fluids, the stability of active crystals is independent of the nature of the propulsion mechanism at the single-particle level. The square and rectangular lattices are found to be linearly unstable at short wavelengths provided the volume fraction of the crystals is high enough. Differently, hexagonal, oblique, and face-centered crystals are always unstable. Our work provides a theoretical basis for future experimental work on flowing microfluidic crystals. PMID:22864543

  3. Hydromechanical transmission with hydrodynamic drive

    DOEpatents

    Orshansky, Jr., deceased, Elias; Weseloh, William E.

    1979-01-01

    This transmission has a first planetary gear assembly having first input means connected to an input shaft, first output means, and first reaction means, and a second planetary gear assembly having second input means connected to the first input means, second output means, and second reaction means connected directly to the first reaction means by a reaction shaft. First clutch means, when engaged, connect the first output means to an output shaft in a high driving range. A hydrodynamic drive is used; for example, a torque converter, which may or may not have a stationary case, has a pump connected to the second output means, a stator grounded by an overrunning clutch to the case, and a turbine connected to an output member, and may be used in a starting phase. Alternatively, a fluid coupling or other type of hydrodynamic drive may be used. Second clutch means, when engaged, for connecting the output member to the output shaft in a low driving range. A variable-displacement hydraulic unit is mechanically connected to the input shaft, and a fixed-displacement hydraulic unit is mechanically connected to the reaction shaft. The hydraulic units are hydraulically connected together so that when one operates as a pump the other acts as a motor, and vice versa. Both clutch means are connected to the output shaft through a forward-reverse shift arrangement. It is possible to lock out the torque converter after the starting phase is over.

  4. The hydrodynamics of lamprey locomotion

    NASA Astrophysics Data System (ADS)

    Leftwich, Megan C.

    The lamprey, an anguilliform swimmer, propels itself by undulating most of its body. This type of swimming produces flow patterns that are highly three-dimensional in nature and not very well understood. However, substantial previous work has been done to understand two-dimensional unsteady propulsion, the possible wake structures and thrust performance. Limited studies of three-dimensional propulsors with simple geometries have displayed the importance of the third dimension in designing unsteady swimmers. Some of the results of those studies, primarily the ways in which vorticity is organized in the wake region, are seen in lamprey swimming as well. In the current work, the third dimension is not the only important factor, but complex geometry and body undulations also contribute to the hydrodynamics. Through dye flow visualization, particle induced velocimetry and pressure measurements, the hydrodynamics of anguilliform swimming are studied using a custom built robotic lamprey. These studies all indicate that the undulations of the body are not producing thrust. Instead, it is the tail which acts to propel the animal. This conclusion led to further investigation of the tail, specifically the role of varying tail flexibility on hydrodymnamics. It is found that by making the tail more flexible, one decreases the coherence of the vorticity in the lamprey's wake. Additional flexibility also yields less thrust.

  5. Fetal and Neonatal HPA Axis.

    PubMed

    Wood, Charles E; Walker, Claire-Dominique

    2015-01-01

    Stress is an integral part of life. Activation of the hypothalamus-pituitary-adrenal (HPA) axis in the adult can be viewed as mostly adaptive to restore homeostasis in the short term. When stress occurs during development, and specifically during periods of vulnerability in maturing systems, it can significantly reprogram function, leading to pathologies in the adult. Thus, it is critical to understand how the HPA axis is regulated during developmental periods and what are the factors contributing to shape its activity and reactivity to environmental stressors. The HPA axis is not a passive system. It can actively participate in critical physiological regulation, inducing parturition in the sheep for instance or being a center stage actor in the preparation of the fetus to aerobic life (lung maturation). It is also a major player in orchestrating mental function, metabolic, and cardiovascular function often reprogrammed by stressors even prior to conception through epigenetic modifications of gametes. In this review, we review the ontogeny of the HPA axis with an emphasis on two species that have been widely studied-sheep and rodents-because they each share many similar regulatory mechanism applicable to our understanding of the human HPA axis. The studies discussed in this review should ultimately inform us about windows of susceptibility in the developing brain and the crucial importance of early preconception, prenatal, and postnatal interventions designed to improve parental competence and offspring outcome. Only through informed studies will our public health system be able to curb the expansion of many stress-related or stress-induced pathologies and forge a better future for upcoming generations.

  6. A method of smoothed particle hydrodynamics using spheroidal kernels

    NASA Technical Reports Server (NTRS)

    Fulbright, Michael S.; Benz, Willy; Davies, Melvyn B.

    1995-01-01

    We present a new method of three-dimensional smoothed particle hydrodynamics (SPH) designed to model systems dominated by deformation along a preferential axis. These systems cause severe problems for SPH codes using spherical kernels, which are best suited for modeling systems which retain rough spherical symmetry. Our method allows the smoothing length in the direction of the deformation to evolve independently of the smoothing length in the perpendicular plane, resulting in a kernel with a spheroidal shape. As a result the spatial resolution in the direction of deformation is significantly improved. As a test case we present the one-dimensional homologous collapse of a zero-temperature, uniform-density cloud, which serves to demonstrate the advantages of spheroidal kernels. We also present new results on the problem of the tidal disruption of a star by a massive black hole.

  7. Stress and the reproductive axis.

    PubMed

    Toufexis, D; Rivarola, M A; Lara, H; Viau, V

    2014-09-01

    There exists a reciprocal relationship between the hypothalamic-pituitary-adrenal (HPA) and the hypothalamic-pituitary-gonadal (HPG) axes, wherein the activation of one affects the function of the other and vice versa. For example, both testosterone and oestrogen modulate the response of the HPA axis, whereas activation of the stress axis, especially activation that is repeating or chronic, has an inhibitory effect upon oestrogen and testosterone secretion. Alterations in maternal care can produce significant effects on both HPG and HPA physiology, as well as behaviour in the offspring at adulthood. For example, changes in reproductive behaviour induced by altered maternal care may alter the expression of sex hormone receptors such as oestrogen receptor (ER)α that govern sexual behaviour, and may be particularly important in determining the sexual strategies utilised by females. Stress in adulthood continues to mediate HPG activity in females through activation of a sympathetic neural pathway originating in the hypothalamus and releasing norepinephrine into the ovary, which produces a noncyclic anovulatory ovary that develops cysts. In the opposite direction, sex differences and sex steroid hormones regulate the HPA axis. For example, although serotonin (5-HT) has a stimulatory effect on the HPA axis in humans and rodents that is mediated by the 5-HT1A receptor, only male rodents respond to 5-HT1A antagonism to show increased corticosterone responses to stress. Furthermore, oestrogen appears to decrease 5-HT1A receptor function at presynaptic sites, yet increases 5-HT1A receptor expression at postsynaptic sites. These mechanisms could explain the heightened stress HPA axis responses in females compared to males. Studies on female rhesus macaques show that chronic stress in socially subordinate female monkeys produces a distinct behavioural phenotype that is largely unaffected by oestrogen, a hyporesponsive HPA axis that is hypersensitive to the modulating effects

  8. Stress and the Reproductive Axis

    PubMed Central

    Toufexis, Donna; Rivarola, Maria Angelica; Lara, Hernan; Viau, Victor

    2014-01-01

    There exists a reciprocal relationship between the hypothalamic-pituitary-adrenal (HPA) and the hypothalamic-pituitary-gonadal (HPG) axes wherein the activation of one affects the function of the other and vice versa. For instance, both testosterone and oestrogen modulate the response of the HPA axis, while activation of the stress axis, especially activation that is repeating or chronic, has an inhibitory effect upon oestrogen and testosterone secretion. Alterations in maternal care can produce significant effects on both HPG and HPA physiology and behaviour in the offspring at adulthood. For example, changes in reproductive behaviour induced by altered maternal care may alter the expression of sex hormone receptors like ERα that govern sexual behaviour, and may be particularly important in determining the sexual strategies utilized by females. Stress in adulthood continues to mediate HPG activity in females through activation of a sympathetic neural pathway originating in the hypothalamus and releasing norepinephrine (NE) into the ovary, which produces a non-cyclic anovulatory ovary that develops cysts. In the opposite direction, sex differences and sex steroid hormones regulate the HPA axis. For example, although serotonin (5-HT) has a stimulatory effect on the HPA axis in humans and rodents that is mediated by the 5-HT1A receptor, only male rodents respond to 5-HT1A antagonism to show increased corticosterone responses to stress. Furthermore, oestrogen appears to decrease 5-HT1A receptor function at presynaptic sites, yet increase 5-HT1A receptor expression at postsynaptic sites. These mechanisms could explain heightened stress HPA axis responses in females compared to males. Studies on female rhesus macaques show that chronic stress in socially subordinate female monkeys produces a distinct behavioral phenotype that is largely unaffected by oestrogen, a hypo-responsive HPA axis that is hypersensitive to the modulating effects of oestrogen, and changes in 5-HT

  9. Update on Thermal and Hydrodynamic Simulations on LMJ Cryogenic Targets

    SciTech Connect

    Moll, G.; Charton, S.

    2004-03-15

    The temperature of the cryogenic target inside the hohlraum has been studied with a computational fluid dynamics code (FLUENT). Specific models have been developed and used for both thermal and hydrodynamic calculations.With thermal calculations only, we first have found the optimum heat flux required to counteract the effect of the laser entrance windows. This heat flux is centered on the hohlraum wall along the axis of revolution. With this heat flux, the temperature surface profiles of the capsule and the DT ice layer have been significantly reduced. Second, the sensitivity of the target temperature profiles (capsule and DT layer) relatively to capsule displacement has been determined. Thirdly, the effect of the shield extraction (shield surrounding the cryogenic structure) has been studied and has indicated that the target lifetime before the laser shot is less than 1s. Meanwhile, with hydrodynamic simulations, we have investigated the surface temperature profiles alteration due to He and H{sub 2} mixture convection within the hohlraum.In order to find out the variations between different configurations, results of these studies are given with seven significant digit outputs. Those results only indicate a trend because of the material's properties incertitude and the code approximation.

  10. Computer-assisted assembly and correction simulation for complex axis deviations using the Ilizarov fixator.

    PubMed

    Kochs, A

    1995-01-01

    In axis correction with the Ilizarov ring fixator, the correction results are often insufficient or there are unexpected translation effects, which can be causally attributed to wrong preoperative planning or inaccurate assembly. To avoid such results, computerised simulation was developed. Via digitalisation of the bone outlines traced from X-radiographs with an additional scale, preoperative correction planning can be performed, simulated with normal software. This can be used while constructing the apparatus and positioning the joints. In addition, the translation effect of the bone fragments can be simulated by arbitrarily choosing the pivot of the correction. In transferring the X-radiograph true to scale, one can compare the ring planes before and after correction. It is possible to estimate the necessary distraction as well as compression and thus the postoperative distraction mode. Using computerised planning, the apparatus construction can be optimised and complications caused by misplanning avoided. Not only the inexperienced user can benefit from this aid. PMID:7577222

  11. The reliability of tablet computers in depicting maxillofacial radiographic landmarks

    PubMed Central

    Mahdian, Mina; Sheth, Sonam; Chandhoke, Taranpreet K; Gopalakrishna, Aadarsh; Potluri, Anitha; Yadav, Sumit

    2015-01-01

    Purpose This study was performed to evaluate the reliability of the identification of anatomical landmarks in panoramic and lateral cephalometric radiographs on a standard medical grade picture archiving communication system (PACS) monitor and a tablet computer (iPad 5). Materials and Methods A total of 1000 radiographs, including 500 panoramic and 500 lateral cephalometric radiographs, were retrieved from the de-identified dataset of the archive of the Section of Oral and Maxillofacial Radiology of the University Of Connecticut School Of Dental Medicine. Major radiographic anatomical landmarks were independently reviewed by two examiners on both displays. The examiners initially reviewed ten panoramic and ten lateral cephalometric radiographs using each imaging system, in order to verify interoperator agreement in landmark identification. The images were scored on a four-point scale reflecting the diagnostic image quality and exposure level of the images. Results Statistical analysis showed no significant difference between the two displays regarding the visibility and clarity of the landmarks in either the panoramic or cephalometric radiographs. Conclusion Tablet computers can reliably show anatomical landmarks in panoramic and lateral cephalometric radiographs. PMID:26389060

  12. Radiographic abnormalities among construction workers exposed to quartz containing dust

    PubMed Central

    Tjoe, N; Burdorf, A; Parker, J; Attfield, M; van Duivenbooden, C; Heederik, D

    2003-01-01

    Background: Construction workers are exposed to quartz containing respirable dust, at levels that may cause fibrosis in the lungs. Studies so far have not established a dose-response relation for radiographic abnormalities for this occupational group. Aims: To measure the extent of radiographic abnormalities among construction workers primarily exposed to quartz containing respirable dust. Methods: A cross sectional study on radiographic abnormalities indicative of pneumoconiosis was conducted among 1339 construction workers mainly involved in grinding, (jack)-hammering, drilling, cutting, sawing, and polishing. Radiological abnormalities were determined by median results of the 1980 International Labour Organisation system of three certified "B" readers. Questionnaires were used for assessment of occupational history, presence of respiratory diseases, and symptoms and smoking habits. Results: An abnormality of ILO profusion category 1/0 and greater was observed on 10.2% of the chest radiographs, and profusion category of 1/1 or greater on 2.9% of the radiographs. The average duration of exposure of this group was 19 years and the average age was 42. The predominant type of small opacities (irregularly shaped) is presumably indicative of mixed dust pneumoconiosis. The prevalence of early signs of nodular silicosis (small rounded opacities of category 1/0 or greater) was low (0.8%). Conclusions: The study suggests an elevated risk of radiographic abnormalities among these workers with expected high exposure. An association between radiographic abnormalities and cumulative exposure to quartz containing dust from construction sites was observed, after correction for potentially confounding variables. PMID:12771392

  13. Performance of radiographers in mammogram interpretation: a systematic review.

    PubMed

    van den Biggelaar, F J H M; Nelemans, P J; Flobbe, K

    2008-02-01

    Radiologists may be relieved from work that could be performed by radiographers. This systematic literature review focuses on the performance of radiographers (also referring to technologists and physician assistants) compared with radiologists in the interpretation of mammograms; the effect of training; and the question whether there are any studies evaluating the effects of involving radiographers in the interpretation of diagnostic mammograms in daily clinical practice on the sensitivity and specificity of cancer detection in breast imaging. Six studies met the inclusion criteria (primary aim of the study has to be the evaluation of the performance of radiographers, sensitivity and specificity have to be reported or calculable and there has to be a sufficient gold standard). The results showed that, in a screening setting, radiographers scored higher false positive rates with a similar sensitivity in the detection of malignancies, compared with radiologists. Furthermore, results suggested that training could improve their performance. No studies were reported assessing the performance of radiographers interpreting diagnostic mammograms in a consecutive patient population in a daily clinical setting. This indicates a need for a well-designed diagnostic study using an adequate gold standard, in order to evaluate the feasibility of deploying radiographers in the interpretation of diagnostic mammograms in a clinical setting. PMID:17764941

  14. Relativistic Hydrodynamics for Heavy-Ion Collisions

    ERIC Educational Resources Information Center

    Ollitrault, Jean-Yves

    2008-01-01

    Relativistic hydrodynamics is essential to our current understanding of nucleus-nucleus collisions at ultrarelativistic energies (current experiments at the Relativistic Heavy Ion Collider, forthcoming experiments at the CERN Large Hadron Collider). This is an introduction to relativistic hydrodynamics for graduate students. It includes a detailed…

  15. Hydrodynamic models of a Cepheid atmosphere

    NASA Technical Reports Server (NTRS)

    Karp, A. H.

    1975-01-01

    Instead of computing a large number of coarsely zoned hydrodynamic models covering the entire atmospheric instability strip, the author computed a single model as well as computer limitations allow. The implicit hydrodynamic code of Kutter and Sparks was modified to include radiative transfer effects in optically thin zones.

  16. Hydrodynamic description for ballistic annihilation systems

    SciTech Connect

    Garcia de Soria, Maria Isabel; Trizac, Emmanuel; Maynar, Pablo; Schehr, Gregory; Barrat, Alain

    2009-01-21

    The problem of the validity of a hydrodynamic description for a system in which there are no collisional invariants is addressed. Hydrodynamic equations have been derived and successfully tested against simulation data for a system where particles annihilate with a probability p, or collide elastically otherwise. The response of the system to a linear perturbation is analyzed as well.

  17. Angle interferometer cross axis errors

    SciTech Connect

    Bryan, J.B.; Carter, D.L.; Thompson, S.L.

    1994-01-01

    Angle interferometers are commonly used to measure surface plate flatness. An error can exist when the centerline of the double comer cube mirror assembly is not square to the surface plate and the guide bar for the mirror sled is curved. Typical errors can be one to two microns per meter. A similar error can exist in the calibration of rotary tables when the centerline of the double comer cube mirror assembly is not square to the axes of rotation of the angle calibrator and the calibrator axis is not parallel to the rotary table axis. Commercial double comer cube assemblies typically have non-parallelism errors of ten milli-radians between their centerlines and their sides and similar values for non-squareness between their centerlines and end surfaces. The authors have developed a simple method for measuring these errors and correcting them by remachining the reference surfaces.

  18. Comparative Hydrodynamics of Bacterial Polymorphism

    NASA Astrophysics Data System (ADS)

    Spagnolie, Saverio E.; Lauga, Eric

    2011-02-01

    Most bacteria swim through fluids by rotating helical flagella which can take one of 12 distinct polymorphic shapes, the most common of which is the normal form used during forward swimming runs. To shed light on the prevalence of the normal form in locomotion, we gather all available experimental measurements of the various polymorphic forms and compute their intrinsic hydrodynamic efficiencies. The normal helical form is found to be the most efficient of the 12 polymorphic forms by a significant margin—a conclusion valid for both the peritrichous and polar flagellar families, and robust to a change in the effective flagellum diameter or length. Hence, although energetic costs of locomotion are small for bacteria, fluid mechanical forces may have played a significant role in the evolution of the flagellum.

  19. Hydrodynamic enhanced dielectrophoretic particle trapping

    DOEpatents

    Miles, Robin R.

    2003-12-09

    Hydrodynamic enhanced dielectrophoretic particle trapping carried out by introducing a side stream into the main stream to squeeze the fluid containing particles close to the electrodes producing the dielelectrophoretic forces. The region of most effective or the strongest forces in the manipulating fields of the electrodes producing the dielectrophoretic forces is close to the electrodes, within 100 .mu.m from the electrodes. The particle trapping arrangement uses a series of electrodes with an AC field placed between pairs of electrodes, which causes trapping of particles along the edges of the electrodes. By forcing an incoming flow stream containing cells and DNA, for example, close to the electrodes using another flow stream improves the efficiency of the DNA trapping.

  20. Radiation hydrodynamics in solar flares

    SciTech Connect

    Fisher, G.H.

    1985-10-18

    Solar flares are rather violent and extremely complicated phenomena, and it should be made clear at the outset that a physically complete picture describing all aspects of flares does not exist. From the wealth of data which is available, it is apparent that many different types of physical processes are involved during flares: energetic particle acceleration, rapid magnetohydrodynamic motion of complex field structures, magnetic reconnection, violent mass motion along magnetic field lines, and the heating of plasma to tens of millions of degrees, to name a few. The goal of this paper is to explore just one aspect of solar flares, namely, the interaction of hydrodynamics and radiation processes in fluid being rapidly heated along closed magnetic field lines. The models discussed are therefore necessarily restrictive, and will address only a few of the observed or observable phenomena. 46 refs., 6 figs.

  1. Integration of quantum hydrodynamical equation

    NASA Astrophysics Data System (ADS)

    Ulyanova, Vera G.; Sanin, Andrey L.

    2007-04-01

    Quantum hydrodynamics equations describing the dynamics of quantum fluid are a subject of this report (QFD).These equations can be used to decide the wide class of problem. But there are the calculated difficulties for the equations, which take place for nonlinear hyperbolic systems. In this connection, It is necessary to impose the additional restrictions which assure the existence and unique of solutions. As test sample, we use the free wave packet and study its behavior at the different initial and boundary conditions. The calculations of wave packet propagation cause in numerical algorithm the division. In numerical algorithm at the calculations of wave packet propagation, there arises the problem of division by zero. To overcome this problem we have to sew together discrete numerical and analytical continuous solutions on the boundary. We demonstrate here for the free wave packet that the numerical solution corresponds to the analytical solution.

  2. Hydrodynamic assembly for Fast Ignition

    NASA Astrophysics Data System (ADS)

    Tabak, Max; Clark, Daniel; Town, Richard; Hatchett, Stephen

    2007-11-01

    We present directly and indirectly driven implosion designs for Fast Ignition. Directly driven designs using various laser illumination wavelengths are described. We compare these designs with simple hydrodynamic efficiency models. Capsules illuminated with less than 1 MJ of light with perfect zooming at low intensity and low contrast ratio in power can assemble 4 mg of fuel to column density in excess of 3 g/cm^2. We contrast these designs with more optimized designs that lead to Guderley-style self similar implosions. Indirectly driven capsules absorbing 75 kJ of xrays can assemble 0.7 mg to column density 2.7 g/cm^2 in 1D simulations. We describe 2-D simulations including both capsules and attached cones driven by radiation. We describe issues in assembling fuel near the cone tip and cone disruption.

  3. Hydrodynamic model for drying emulsions.

    PubMed

    Feng, Huanhuan; Sprakel, Joris; van der Gucht, Jasper

    2015-08-01

    We present a hydrodynamic model for film formation in a dense oil-in-water emulsion under a unidirectional drying stress. Water flow through the plateau borders towards the drying end leads to the buildup of a pressure gradient. When the local pressure exceeds the critical disjoining pressure, the water films between droplets break and the droplets coalesce. We show that, depending on the critical pressure and the evaporation rate, the coalescence can occur in two distinct modes. At low critical pressures and low evaporation rates, coalescence occurs throughout the sample, whereas at high critical pressures and high evaporation rate, coalescence occurs only at the front. In the latter case, an oil layer develops on top of the film, which acts as a diffusive barrier and slows down film formation. Our findings, which are summarized in a state diagram for film formation, are in agreement with recent experimental findings.

  4. Anomalous hydrodynamics kicks neutron stars

    NASA Astrophysics Data System (ADS)

    Kaminski, Matthias; Uhlemann, Christoph F.; Bleicher, Marcus; Schaffner-Bielich, Jürgen

    2016-09-01

    Observations show that, at the beginning of their existence, neutron stars are accelerated briskly to velocities of up to a thousand kilometers per second. We argue that this remarkable effect can be explained as a manifestation of quantum anomalies on astrophysical scales. To theoretically describe the early stage in the life of neutron stars we use hydrodynamics as a systematic effective-field-theory framework. Within this framework, anomalies of the Standard Model of particle physics as underlying microscopic theory imply the presence of a particular set of transport terms, whose form is completely fixed by theoretical consistency. The resulting chiral transport effects in proto-neutron stars enhance neutrino emission along the internal magnetic field, and the recoil can explain the order of magnitude of the observed kick velocities.

  5. IKT for quantum hydrodynamic equations

    NASA Astrophysics Data System (ADS)

    Tessarotto, Massimo; Ellero, Marco; Nicolini, Piero

    2007-11-01

    A striking feature of standard quantum mechanics (SQM) is its analogy with classical fluid dynamics. In fact, it is well-known that the Schr"odinger equation is equivalent to a closed set of partial differential equations for suitable real-valued functions of position and time (denoted as quantum fluid fields) [Madelung, 1928]. In particular, the corresponding quantum hydrodynamic equations (QHE) can be viewed as the equations of a classical compressible and non-viscous fluid, endowed with potential velocity and quantized velocity circulation. In this reference, an interesting theoretical problem, in its own right, is the construction of an inverse kinetic theory (IKT) for such a type of fluids. In this note we intend to investigate consequences of the IKT recently formulated for QHE [M.Tessarotto et al., Phys. Rev. A 75, 012105 (2007)]. In particular a basic issue is related to the definition of the quantum fluid fields.

  6. Hypothalamus-Pituitary-Thyroid Axis.

    PubMed

    Ortiga-Carvalho, Tania M; Chiamolera, Maria I; Pazos-Moura, Carmen C; Wondisford, Fredic E

    2016-01-01

    The hypothalamus-pituitary-thyroid (HPT) axis determines the set point of thyroid hormone (TH) production. Hypothalamic thyrotropin-releasing hormone (TRH) stimulates the synthesis and secretion of pituitary thyrotropin (thyroid-stimulating hormone, TSH), which acts at the thyroid to stimulate all steps of TH biosynthesis and secretion. The THs thyroxine (T4) and triiodothyronine (T3) control the secretion of TRH and TSH by negative feedback to maintain physiological levels of the main hormones of the HPT axis. Reduction of circulating TH levels due to primary thyroid failure results in increased TRH and TSH production, whereas the opposite occurs when circulating THs are in excess. Other neural, humoral, and local factors modulate the HPT axis and, in specific situations, determine alterations in the physiological function of the axis. The roles of THs are vital to nervous system development, linear growth, energetic metabolism, and thermogenesis. THs also regulate the hepatic metabolism of nutrients, fluid balance and the cardiovascular system. In cells, TH actions are mediated mainly by nuclear TH receptors (210), which modify gene expression. T3 is the preferred ligand of THR, whereas T4, the serum concentration of which is 100-fold higher than that of T3, undergoes extra-thyroidal conversion to T3. This conversion is catalyzed by 5'-deiodinases (D1 and D2), which are TH-activating enzymes. T4 can also be inactivated by conversion to reverse T3, which has very low affinity for THR, by 5-deiodinase (D3). The regulation of deiodinases, particularly D2, and TH transporters at the cell membrane control T3 availability, which is fundamental for TH action. © 2016 American Physiological Society. Compr Physiol 6:1387-1428, 2016. PMID:27347897

  7. Effect of Surface Roughness on Hydrodynamic Bearings

    NASA Technical Reports Server (NTRS)

    Majumdar, B. C.; Hamrock, B. J.

    1981-01-01

    A theoretical analysis on the performance of hydrodynamic oil bearings is made considering surface roughness effect. The hydrodynamic as well as asperity contact load is found. The contact pressure was calculated with the assumption that the surface height distribution was Gaussian. The average Reynolds equation of partially lubricated surface was used to calculate hydrodynamic load. An analytical expression for average gap was found and was introduced to modify the average Reynolds equation. The resulting boundary value problem was then solved numerically by finite difference methods using the method of successive over relaxation. The pressure distribution and hydrodynamic load capacity of plane slider and journal bearings were calculated for various design data. The effects of attitude and roughness of surface on the bearing performance were shown. The results are compared with similar available solution of rough surface bearings. It is shown that: (1) the contribution of contact load is not significant; and (2) the hydrodynamic and contact load increase with surface roughness.

  8. Stellar Explosions: Hydrodynamics and Nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Jose, Jordi

    2016-01-01

    Stars are the main factories of element production in the universe through a suite of complex and intertwined physical processes. Such stellar alchemy is driven by multiple nuclear interactions that through eons have transformed the pristine, metal-poor ashes leftover by the Big Bang into a cosmos with 100 distinct chemical species. The products of stellar nucleosynthesis frequently get mixed inside stars by convective transport or through hydrodynamic instabilities, and a fraction of them is eventually ejected into the interstellar medium, thus polluting the cosmos with gas and dust. The study of the physics of the stars and their role as nucleosynthesis factories owes much to cross-fertilization of different, somehow disconnected fields, ranging from observational astronomy, computational astrophysics, and cosmochemistry to experimental and theoretical nuclear physics. Few books have simultaneously addressed the multidisciplinary nature of this field in an engaging way suitable for students and young scientists. Providing the required multidisciplinary background in a coherent way has been the driving force for Stellar Explosions: Hydrodynamics and Nucleosynthesis. Written by a specialist in stellar astrophysics, this book presents a rigorous but accessible treatment of the physics of stellar explosions from a multidisciplinary perspective at the crossroads of computational astrophysics, observational astronomy, cosmochemistry, and nuclear physics. Basic concepts from all these different fields are applied to the study of classical and recurrent novae, type I and II supernovae, X-ray bursts and superbursts, and stellar mergers. The book shows how a multidisciplinary approach has been instrumental in our understanding of nucleosynthesis in stars, particularly during explosive events.

  9. Stellar Explosions: Hydrodynamics and Nucleosynthesis

    NASA Astrophysics Data System (ADS)

    José, Jordi

    2015-12-01

    Stars are the main factories of element production in the universe through a suite of complex and intertwined physical processes. Such stellar alchemy is driven by multiple nuclear interactions that through eons have transformed the pristine, metal-poor ashes leftover by the Big Bang into a cosmos with 100 distinct chemical species. The products of stellar nucleosynthesis frequently get mixed inside stars by convective transport or through hydrodynamic instabilities, and a fraction of them is eventually ejected into the interstellar medium, thus polluting the cosmos with gas and dust. The study of the physics of the stars and their role as nucleosynthesis factories owes much to cross-fertilization of different, somehow disconnected fields, ranging from observational astronomy, computational astrophysics, and cosmochemistry to experimental and theoretical nuclear physics. Few books have simultaneously addressed the multidisciplinary nature of this field in an engaging way suitable for students and young scientists. Providing the required multidisciplinary background in a coherent way has been the driving force for Stellar Explosions: Hydrodynamics and Nucleosynthesis. Written by a specialist in stellar astrophysics, this book presents a rigorous but accessible treatment of the physics of stellar explosions from a multidisciplinary perspective at the crossroads of computational astrophysics, observational astronomy, cosmochemistry, and nuclear physics. Basic concepts from all these different fields are applied to the study of classical and recurrent novae, type I and II supernovae, X-ray bursts and superbursts, and stellar mergers. The book shows how a multidisciplinary approach has been instrumental in our understanding of nucleosynthesis in stars, particularly during explosive events.

  10. The hydrodynamics of dolphin drafting

    PubMed Central

    Weihs, Daniel

    2004-01-01

    Background Drafting in cetaceans is defined as the transfer of forces between individuals without actual physical contact between them. This behavior has long been surmised to explain how young dolphin calves keep up with their rapidly moving mothers. It has recently been observed that a significant number of calves become permanently separated from their mothers during chases by tuna vessels. A study of the hydrodynamics of drafting, initiated in the hope of understanding the mechanisms causing the separation of mothers and calves during fishing-related activities, is reported here. Results Quantitative results are shown for the forces and moments around a pair of unequally sized dolphin-like slender bodies. These include two major effects. First, the so-called Bernoulli suction, which stems from the fact that the local pressure drops in areas of high speed, results in an attractive force between mother and calf. Second is the displacement effect, in which the motion of the mother causes the water in front to move forwards and radially outwards, and water behind the body to move forwards to replace the animal's mass. Thus, the calf can gain a 'free ride' in the forward-moving areas. Utilizing these effects, the neonate can gain up to 90% of the thrust needed to move alongside the mother at speeds of up to 2.4 m/sec. A comparison with observations of eastern spinner dolphins (Stenella longirostris) is presented, showing savings of up to 60% in the thrust that calves require if they are to keep up with their mothers. Conclusions A theoretical analysis, backed by observations of free-swimming dolphin schools, indicates that hydrodynamic interactions with mothers play an important role in enabling dolphin calves to keep up with rapidly moving adult school members. PMID:15132740

  11. Progressive diaphyseal dysplasia (Engelmann disease): scintigraphic-radiographic-clinical correlations

    SciTech Connect

    Kumar, B.; Murphy, W.A.; Whyte, M.P.

    1981-07-01

    Four patients (2 males, 2 females; ages 15-47 yrs.) with variable clinical, radiographic, and scintigraphic manifestations of progressive diaphyseal dysplasia (PDD) or Engelmann disease were studied with 99mTc methylene diphosphonate bone imaging and radiographic skeletal surveys. Comparison of the results of the two imaging procedures showed that some affected bones were scintigraphically normal but radiographically abnormal and vice versa. These findings suggest that the lesions of PDD may mature, causing a significant decrease in disease activity, and that abnormally increased radiopharmaceutical accumulation during bone scintigraphy appears to be a sensitive indicator of disease activity.

  12. Integration of radiographic images with an electronic medical record.

    PubMed Central

    Overhage, J. M.; Aisen, A.; Barnes, M.; Tucker, M.; McDonald, C. J.

    2001-01-01

    Radiographic images are important and expensive diagnostic tests. However, the provider caring for the patient often does not review the images directly due to time constraints. Institutions can use picture archiving and communications systems to make images more available to the provider, but this may not be the best solution. We integrated radiographic image review into the Regenstrief Medical Record System in order to address this problem. To achieve adequate performance, we store JPEG compressed images directly in the RMRS. Currently, physicians review about 5% of all radiographic studies using the RMRS image review function. PMID:11825241

  13. Comparison of radiographic and radionuclide skeletal surveys in battered children

    SciTech Connect

    Pickett, W.J.; Faleski, E.J.; Chacko, A.; Jarrett, R.V.

    1983-02-01

    A review of 13 cases of suspected child abuse in which radionuclide (RN) scans, radiographic skeletal surveys, and sufficient follow-up were available showed that the RN scans were insensitive, even though fractures were more than 48 hours old at the time of the scan. Frequently missed lesions included skull and extremity fractures. Furthermore, soft tissue and visceral abnormalities that were identified on radiographic examination went undetected on RN scan. We conclude that, although the RN scan may augment the radiographic examination, it should not be used alone to screen for the battered child.

  14. Image analysis of chest radiographs. Final report

    SciTech Connect

    Hankinson, J.L.

    1982-06-01

    The report demonstrates the feasibility of using a computer for automated interpretation of chest radiographs for pneumoconiosis. The primary goal of this project was to continue testing and evaluating the prototype system with a larger set of films. After review of the final contract report and a review of the current literature, it was clear that several modifications to the prototype system were needed before the project could continue. These modifications can be divided into two general areas. The first area was in improving the stability of the system and compensating for the diversity of film quality which exists in films obtained in a surveillance program. Since the system was to be tested with a large number of films, it was impractical to be extremely selective of film quality. The second area is in terms of processing time. With a large set of films, total processing time becomes much more significant. An image display was added to the system so that the computer determined lung boundaries could be verified for each film. A film handling system was also added, enabling the system to scan films continuously without attendance.

  15. Enhancing skeletal features in digitally reconstructed radiographs

    NASA Astrophysics Data System (ADS)

    Fu, Dongshan; Kuduvalli, Gopinath

    2006-03-01

    Generation of digitally reconstructed radiographs (DRR) is a critical part of 2D-3D image registration that is utilized in patient position alignment for image-guided radiotherapy and radiosurgery. The DRRs are generated from a pre-operative CT scan and used as the references to match the X-ray images for determining the change of patient position. Skeletal structures are the primary image features to facilitate the registration between the DRR and X-ray images. In this paper, we present a method to enhance skeletal features of spinal regions in DRRs. The attenuation coefficient at each voxel is first calculated by applying an exponential transformation of the original attenuation coefficient in the CT scan. This is a preprocessing step that is performed prior to DRR generation. The DRR is then generated by integrating the newly calculated attenuation coefficients along the ray that connects the X-ray source and the pixel in the DRR. Finally, the DRR is further enhanced using a weighted top-hat filter. During the entire process, because there is no original CT information lost, even the small skeletal features contributed by low intensity part of CT data are preserved in the enhanced DRRs. Experiments on clinical data were conducted to compare the image quality of DRRs with and without enhancement. The results showed that the image contrast of skeletal features in the enhanced DRRs is significantly improved. This method has potential to be applied for more accurate and robust 2D-3D image registration.

  16. Radiographic association of schwannomas with sensory ganglia

    PubMed Central

    Tryggvason, Geir; Barnett, Andrew; Kim, John; Soken, Hakan; Maley, Joan; Hansen, Marlan R.

    2012-01-01

    Objective Clinical experience suggests that the majority of schwannomas arise within sensory ganglia, suggesting that intraganglionic glial cells represent a potential cell of origin for schwannomas. To support this clinical impression, we reviewed magnetic resonance imaging (MRI) studies performed over a 5 year period at our institution to determine the relationship of cranial and spinal nerve schwannomas with the ganglia of the associated nerves. Study design Retrospective cohort study Setting Tertiary referral center Patients Patients undergoing imaging study at our institution over a 5 year period. Intervention(s) Radiographical images at our institution were reviewed as well as published studies to determine the anatomic location of schwannomas. Main outcome measure(s) Anatomical location of schwannomas Results A total of 372 patients were found over the 5-year study period, 31 of those were diagnosed with neurofibromatosis type 2 (NF2). Vestibular schwannomas comprised the greatest number of schwannomas, followed by spinal schwannomas. In NF2 patients, spinal schwannomas were the most common tumor, followed by vestibular schwannomas. In NF2 patients and those with sporadic schwannomas, the overwhelming majority of tumors arose in nerves with a sensory component and were associated with sensory ganglia of the nerves (562/607, 92.6%). Very few tumors arose from pure motor nerves. This is supported by review of published articles on anatomic location of schwannomas. Conclusions Schwannomas are strongly associated anatomically with ganglia of sensory nerves. These findings raise the possibility that intraganglionic glial cells give rise to the majority of schwannomas. PMID:22858714

  17. Hydroelastic dynamic characteristics of a slender axis-symmetric body

    NASA Astrophysics Data System (ADS)

    Chen, Weimin; Li, Min; Zheng, Zhongqin; Zhang, Liwu

    2010-07-01

    The slender axis-symmetric submarine body moving in the vertical plane is the object of our investigation. A coupling model is developed where displacements of a solid body as a Euler beam (consisting of rigid motions and elastic deformations) and fluid pressures are employed as basic independent variables, including the interaction between hydrodynamic forces and structure dynamic forces. Firstly the hydrodynamic forces, depending on and conversely influencing body motions, are taken into account as the governing equations. The expressions of fluid pressure are derived based on the potential theory. The characteristics of fluid pressure, including its components, distribution and effect on structure dynamics, are analyzed. Then the coupling model is solved numerically by means of a finite element method (FEM). This avoids the complicacy, combining CFD (fluid) and FEM (structure), of direct numerical simulation, and allows the body with a non-strict ideal shape so as to be more suitable for practical engineering. An illustrative example is given in which the hydroelastic dynamic characteristics, natural frequencies and modes of a submarine body are analyzed and compared with experimental results. Satisfactory agreement is observed and the model presented in this paper is shown to be valid.

  18. GAMMA-RAY BURSTS ARE OBSERVED OFF-AXIS

    SciTech Connect

    Ryan, Geoffrey; Van Eerten, Hendrik; MacFadyen, Andrew; Zhang, Bin-Bin

    2015-01-20

    We constrain the jet opening angle and, for the first time, the off-axis observer angle for gamma-ray bursts in the Swift-XRT catalog by using the ScaleFit package to fit afterglow light curves directly to hydrodynamic simulations. The ScaleFit model uses scaling relations in the hydrodynamic and radiation equations to compute synthetic light curves directly from a set of high-resolution two-dimensional relativistic blast wave simulations. The data sample consists of all Swift-XRT afterglows from 2005 to 2012 with sufficient coverage and a known redshift, 226 bursts in total. We find that the jet half-opening angle varies widely but is commonly less than 0.1 rad. The distribution of the electron spectral index is also broad, with a median at 2.30. We find the observer angle to have a median value of 0.57 of the jet opening angle over our sample, which has profound consequences for the predicted rate of observed jet breaks and affects the beaming-corrected total energies of gamma-ray bursts.

  19. Computed tomography scanogram compared to long leg radiograph for determining axial knee alignment

    PubMed Central

    Holme, Thomas J; Henckel, Johann; Hartshorn, Kai; Cobb, Justin P; Hart, Alister J

    2015-01-01

    Background and purpose Supine computed tomography scanogram (CTS) is a commonly used alternative to weight bearing long leg plain radiograph (LLR) in measuring knee alignment. No published studies have validated its use in the native knee and the post-unicompartmental replacement knee (UKR). We quantified the difference in measurements obtained from CTS and LLR for knee alignment. Patients and methods Supine CT scanograms and weight bearing long leg plain anteroposterior radiographs were obtained for 40 knees (in 25 patients), 17 of which were native, and 23 of which were post-UKR. The mechanical and anatomical axes of the tibio-femoral joint were measured. Bland-Altman plots were used to calculate the 1.96 standard deviation limits of agreement between CTS and LLR. Intraclass correlation was used to assess intra-rater and inter-rater reliability (where values > 0.81 indicate very good reliability). Results CTS and LLR were equally reliable in measurement of the mechanical and anatomical axes of the tibio-femoral joint (intraclass correlation coefficient (ICC) > 0.9 for all parameters). Statistically significant and clinically relevant differences were found between CTS and LLR in measurement of the mechanical axis (limits of agreement: UKR −3.2° to 6.3°; native −3.2° to 5.6°) and the anatomical axis (limits of agreement: UKR −3.7° to 8.7°; native −2.0° to 8.8°). Interpretation Although it is a reliable tool, CTS is not necessarily an accurate one for measurement of knee alignment when compared to LLR. We recommend that CTS should not be used as a substitute for LLR in measurement of the mechanical or anatomical axes of the knee. PMID:25582134

  20. Extraction Kickers and Modulators for the advanced Hydrodynamic Facility

    SciTech Connect

    Walstrom, P L; Cook, E G

    2001-06-12

    In order to exploit the full potential of the Advanced Hydrodynamic Facility (AHF) facility to produce a time sequence of proton transmission radiographs throughout the dynamic event, a kicker/modulator for extraction from the 50 GeV ring that is capable of generating a string of 25 pulse pairs at arbitrary times within a total time duration of 100 microseconds or more is desired. The full range of desired pulse-train requirements cannot be met with the commonly used pulse-forming cables or networks (PFNs) switched with thyratrons. The preferred modulator design approach at present is a transformer voltage-adder concept with primary-side pulses formed with MOSFET-switched capacitors. This modulator will be a scale-up of an existing modulator that has been developed by Lawrence Livermore National Laboratory for use in DARHT, an electron induction accelerator facility at Los Alamos National Laboratory. Before the voltage-adder concept can be adopted for use in AHF, a working prototype that meets the AHF requirements for the pulse voltage, current, rise and fall time, and total pulse number must be built and tested. Additional requirements for pulse-to-pulse flattop height variation and baseline shift must also be met. A development and testing plan for the voltage-adder kicker modulator for AHF is described.

  1. Shock-hydrodynamics experiments on the Nova laser

    SciTech Connect

    Miller, P.; Peyser, T.; Stry, P.; Budil, K.; Wojtowicz, D.; Burke, E.

    1995-08-01

    We have conducted shock-induced hydrodynamics experiments using the Nova laser at Lawrence Livermore National Laboratory. The laser provides a high-enthalpy source by depositing its energy (about 22 kJ) in a small gold cavity called a Hohlraum. The Hohlraum serves as a driver section, launching very strong (M {approx} 20) shocks into millimeter-scale cylindrical ``shock tubes.`` The flow is imaged radiographically by an electronic framing camera, using a laser-generated x-ray source. Several topics have been addressed with this configuration, including shock-induced mixing at density interfaces (seeded with a variety of perturbations); the development of high-speed, shaped-charge-like jets; the effects of geometry on the planarity of the generated shocks; and shock-shock interactions which develop in the flows. This paper describes the general configuration of our experiments, presents an overview of the high-speed jet work, discusses some of our findings, and compares our results with computer simulations.

  2. Is the gravity effect of radiographic anatomic features enough to justify stone clearance or fragments retention following extracorporeal shock wave lithotripsy (SWL).

    PubMed

    Mustafa, Mahmoud

    2012-08-01

    We determined whether the gravity effect of radiographic anatomic features on the preoperative urography (IVP) are enough to predict fragments clearance after shock wave lithotripsy (SWL). A Total of 282 patients with mean age 45.8 ± 13.2 years (189 male, 93 female), who underwent SWL due to renal calculi between October 2005 and August 2009 were enrolled. The mean calculi load was 155.72 ± 127.66 mm². The patients were stratified into three groups: patients with pelvis calculi (group 1); patients with upper or middle pole calculi (group 2) and patients with lower pole calculi (group 3). Three angles on the pretreatment IVP were measured: the inner angle between the axis of the lower pole infundibular and ureteropelvic axis (angle I); the inner angle between the lower pole infundibular axis and main axis of pelvis-ureteropelvic (UP) junction point (angle II) and the inner angle between the lower pole infundibular axis and perpendicular line (angle III). Multivariate analysis was used to define the significant predictors of stone clearance. The overall success rate was 85.81%. All angles, sessions number, shock waves number and stone burden were significant predictors of success in patients in group 1. However, in group 2 only angle II and in group 3 angles I and II had significant effect on stone clearance. Radiographic anatomic features have significant role in determining the stone-free rate following satisfactory fragmentation of renal stones with SWL. The measurement of infundibulopelvic angle in different manner helps to predict the stone-free status in patients with renal calculi located not only in lower pole, but also in renal pelvis and upper or middle pole. Gravity effect is not enough to justify the significant influence of the radiographic anatomic features on the stone clearance and fragments retention after SWL.

  3. Susuk - Black Magic Exposed “White” by Dental Radiographs

    PubMed Central

    Mohammed, Faraz

    2014-01-01

    Susuk or charm needles are a facial cum body art widely practiced among women of Malaysia, Brunei, Singapore, Thailand and Indonesia. These are small, needle-shaped metallic talismans inserted subcutaneously in different parts of the body. The concealed art of susuk was “exposed” by routine radiographic examination in the oral and maxillofacial region. This paper reports two such cases of unusual incidental radiographic finding in dental radiographs which were taken on a routine basis as part of the diagnostic work up. This article will also primarily enlighten the importance of radiographs in detecting such charm needles as the wearer keeps the body art a “hidden secret” thereby avoiding misdiagnosis. PMID:25177646

  4. Radiographic visualization of magma dynamics in an erupting volcano

    PubMed Central

    Tanaka, Hiroyuki K. M.; Kusagaya, Taro; Shinohara, Hiroshi

    2014-01-01

    Radiographic imaging of magma dynamics in a volcanic conduit provides detailed information about ascent and descent of magma, the magma flow rate, the conduit diameter and inflation and deflation of magma due to volatile expansion and release. Here we report the first radiographic observation of the ascent and descent of magma along a conduit utilizing atmospheric (cosmic ray) muons (muography) with dynamic radiographic imaging. Time sequential radiographic images show that the top of the magma column ascends right beneath the crater floor through which the eruption column was observed. In addition to the visualization of this magma inflation, we report a sequence of images that show magma descending. We further propose that the monitoring of temporal variations in the gas volume fraction of magma as well as its position in a conduit can be used to support existing eruption prediction procedures. PMID:24614612

  5. Dental Identification Through Endodontic Radiographic Records: a Case Report

    PubMed Central

    Franco, Ademir; Picoli, Fernando Fortes; Nunes, Fernando Gomes; Estrela, Carlos

    2014-01-01

    Objective of work The present study aims to report a case of successful human identification based on the comparison of ante-mortem and post-mortem records of endodontic treatment. Based on these, the legal value of storing and updating clinical records is highlighted throughout the text. Case report An unknown body was recovered from a traffic accident site. Forensic examination was conducted in order to establish the identity of the victim. Based on the absence of ante-mortem fingerprint registration in the national database, the search for AM data was performed using periapical radiographic records from private dental clinics. A positive dental identification was achieved analyzing evidence of endodontic treatment. Conclusion Dental radiographs play a valuable role as legal tools supporting the criminal demands on the daily forensic practice. Specifically in endodontics, periapical radiographs are essential for a proper treatment. In forensics, these radiographs represent a solid source of ante-mortem data for human identifications.

  6. Radiographic visualization of magma dynamics in an erupting volcano.

    PubMed

    Tanaka, Hiroyuki K M; Kusagaya, Taro; Shinohara, Hiroshi

    2014-01-01

    Radiographic imaging of magma dynamics in a volcanic conduit provides detailed information about ascent and descent of magma, the magma flow rate, the conduit diameter and inflation and deflation of magma due to volatile expansion and release. Here we report the first radiographic observation of the ascent and descent of magma along a conduit utilizing atmospheric (cosmic ray) muons (muography) with dynamic radiographic imaging. Time sequential radiographic images show that the top of the magma column ascends right beneath the crater floor through which the eruption column was observed. In addition to the visualization of this magma inflation, we report a sequence of images that show magma descending. We further propose that the monitoring of temporal variations in the gas volume fraction of magma as well as its position in a conduit can be used to support existing eruption prediction procedures.

  7. Radiographic and scintigraphic evaluation of total knee arthroplasty

    SciTech Connect

    Schneider, R.; Soudry, M.

    1986-04-01

    Various radiographic and scintigraphic methods are used to supplement clinical findings in the evaluation of total knee arthroplasty and its complications. Serial roentgenograms offer reliable information for diagnosing mechanical loosening. Wide and extensive radiolucency at the cement-bone interface and shift in position and alignment of prosthetic components can be seen in almost all cases by the time revision is necessary. Radiographic abnormalities are usually not present in acute infection, but are often present in chronic infection. Bone scanning has a high sensitivity for diagnosis of infection or loosening, but is nonspecific because increased uptake is often present around asymptomatic total knee arthroplasties with normal radiographs. Differential bone and Gallium scanning and scanning with Indium 111-labeled leukocytes have a greater specificity for diagnosis of infection than does bone or Gallium scanning alone. Routine radiographic and scintigraphic studies have shown a high incidence of deep vein thrombosis in the calf after total knee arthroplasty. Clinically significant pulmonary embolization is infrequent.

  8. A proposed benchmark for simulation in radiographic testing

    SciTech Connect

    Jaenisch, G.-R.; Deresch, A.; Bellon, C.; Schumm, A.; Guerin, P.

    2014-02-18

    The purpose of this benchmark study is to compare simulation results predicted by various models of radiographic testing, in particular those that are capable of separately predicting primary and scatter radiation for specimens of arbitrary geometry.

  9. Radiographic visualization of magma dynamics in an erupting volcano.

    PubMed

    Tanaka, Hiroyuki K M; Kusagaya, Taro; Shinohara, Hiroshi

    2014-01-01

    Radiographic imaging of magma dynamics in a volcanic conduit provides detailed information about ascent and descent of magma, the magma flow rate, the conduit diameter and inflation and deflation of magma due to volatile expansion and release. Here we report the first radiographic observation of the ascent and descent of magma along a conduit utilizing atmospheric (cosmic ray) muons (muography) with dynamic radiographic imaging. Time sequential radiographic images show that the top of the magma column ascends right beneath the crater floor through which the eruption column was observed. In addition to the visualization of this magma inflation, we report a sequence of images that show magma descending. We further propose that the monitoring of temporal variations in the gas volume fraction of magma as well as its position in a conduit can be used to support existing eruption prediction procedures. PMID:24614612

  10. Generation and Analysis of Wire Rope Digital Radiographic Images

    NASA Astrophysics Data System (ADS)

    Chakhlov, S.; Anpilogov, P.; Batranin, A.; Osipov, S.; Zhumabekova, Sh; Yadrenkin, I.

    2016-06-01

    The paper is dealt with different structures of the digital radiographic system intended for wire rope radiography. The scanning geometry of the wire rope is presented and the main stages of its digital radiographic image generation are identified herein. Correction algorithms are suggested for X-ray beam hardening. A complex internal structure of the wire rope is illustrated by its 25 mm diameter image obtained from X-ray computed tomography. The paper considers the approach to the analysis of digital radiographic image algorithms based on the closeness of certain parameters (invariants) of all unit cross-sections of the reference wire rope or its sections with the length equaling to the lay. The main invariants of wire rope radiographic images are identified and compared with its typical defects.

  11. Radiographic appearance of maxillary sinus feed impaction in a horse.

    PubMed

    Montgomery, James E; Carmalt, James L

    2013-01-01

    A 15-year-old Belgian gelding presented in respiratory distress, with bilateral mucopurulent nasal discharge, and right-sided epistaxis. The horse had a 5-year history of dental disease and had been recently losing weight. Radiographs indicated tooth root abscessation of the right maxillary third molar tooth and probable maxillary sinus feed impaction. These findings were confirmed at surgery and necropsy. The stippled, granular radiographic appearance described here is highly characteristic of sinus feed impaction. PMID:24371923

  12. The 1980 ILO classification of radiographs of the pneumoconioses.

    PubMed

    Shipley, R T

    1992-11-01

    The 1980 ILO classification of radiographs of the pneumoconioses has undergone revision and improvement in response to increases in knowledge and international concerns. Its goal is to standardize the reading and reporting of radiographic manifestations of the inhalation of dust so that international epidemiologic comparisons are possible. It remains an imperfect instrument, but "... although total elimination of variation is impossible, some measure of control can be achieved."

  13. Serum Calcium Concentration Is Inversely Associated With Radiographic Knee Osteoarthritis

    PubMed Central

    Li, Hui; Zeng, Chao; Wei, Jie; Yang, Tuo; Gao, Shu-Guang; Li, Yu-Sheng; Luo, Wei; Xiao, Wen-Feng; Xiong, Yi-Lin; Lei, Guang-Hua

    2016-01-01

    Abstract To examine the relationship between serum calcium (Ca) concentration and radiographic knee osteoarthritis (OA). This study covered a total of 2855 subjects. The serum Ca concentration was detected by the Arsenazo III method. The radiographic OA of the knee was defined as changes equivalent to Kellgren–Lawrence grade 2 on 1 side at least. The serum Ca concentration was categorized into 4 quartiles, which are ≤2.27, 2.28–2.34, 2.35–2.41, and ≥2.42 mmol/L, respectively. The relationship between serum Ca and radiographic knee OA was examined using the multivariable logistic analysis after adjusting a series of potential confounding factors. For each quartile of the relationship between serum Ca concentration and radiographic knee OA, the OR with 95% CI was calculated, and the one with the lowest value was considered to be the reference. An inverse association existed between serum Ca concentration and radiographic OA of the knee in the multivariable model and the model where the factors of age, sex, and BMI were adjusted. The multivariable-adjusted OR (95% CI) for radiographic knee OA in the second, third, and fourth quartiles of serum Ca concentration were 1.05 (95% CI: 0.83–1.31), 1.01 (95% CI: 0.80–1.27), and 0.79 (95% CI: 0.62–1.00), respectively, in comparison with the reference (first) quartile. A trend approaching to statistical significant (P = 0.06) was observed. Meanwhile, the relative odds of radiographic OA of the knee were decreased by 0.79 times in the fourth quartile in comparison with the reference. There is likely to be an inverse association between serum Ca concentration and radiographic OA of the knee. PMID:26871857

  14. Decreasing the density of dark radiographs--a lost art.

    PubMed

    Serman, N J; Padilla, J F

    1990-10-01

    The purpose of this paper is to describe a procedure that appears to have been lost with time and that reduces excess density [immaterial of the cause] on radiographs. This results in radiographs of greatly improved diagnostic quality. This procedure results in avoiding retakes resulting in a lower radiation dose to the patient and a saving of time. This procedure should not be considered as a substitute for poor radiological or processing techniques.

  15. Development of a portable, high-energy radiographic source

    NASA Technical Reports Server (NTRS)

    Reinhart, E. R.; Schonberg, R. G.; Mixon, G. L.; Wenk, S. A.

    1979-01-01

    A two-year program has been undertaken to develop a portable high-energy (3-4 MeV) radiographic system for in-service and repair inspections of components at nuclear power stations. The basic design concept uses a lightweight portable linear accelerator. This paper describes the design objectives, concepts employed, and progress to date. Specific potential applications and accompanying radiographic techniques are discussed, along with novel beam-angulation devices that permit utilization in areas of highly restricted access.

  16. Simulating hydrodynamics on tidal mudflats

    NASA Astrophysics Data System (ADS)

    Cook, S.; Lippmann, T. C.

    2014-12-01

    Biogeochemical cycling in estuaries is governed by fluxes from both riverine sources and through estuarine sediment deposits. Although estimates from river sources are relatively common and easily sampled, estimates of nutrient fluxes through the fluid-sediment interface are less common and limited to deeper portions of the bays away from intertidal areas. Lack of quantifiable shear stress estimates over intertidal areas limits our overall understanding of nutrient budgets in estuaries. Unfortunately, observation of intertidal hydrodynamics and nutrient fluxes over tidal flats and near the water's edge is difficult owing to the temporally varying and spatially extensive region where the tides inundate, and thus numerical modeling is often employed. In this work, the Regional Ocean Modeling System (ROMS), a three dimensional numerical hydrodynamic model was used to investigate the shear stresses over intertidal mudflats in the Great Bay, a tidally-dominated New England estuary cut by several tidal channels and with over 50% of the estuary exposed at low tide. The ROMS wetting and drying scheme was used to simulate the rising and falling tide on the flats, a successful approach adapted in other regions of the world but not always inclusive of tidal channels. Bathymetric data obtained in 2009 and 2013 was used to define the model grid. Predicted tides are forced at Adam's Pt., a natural constriction in the estuary about 20 km upstream of the mouth and at the entrance to the Great Bay. Of particular interest are fluxes of material on-to and off-of the tidal flats which contribute to water quality conditions in the estuary, and are largely governed by shear stresses that drive nutrient fluxes at the fluid-sediment interface. Basin wide estimates of near-bottom shear stresses can be used to estimate first order nutrient fluxes over a tidal cycle and hence describe general biogeochemical dynamics of the estuary. Future work will include enhanced forcing of currents by

  17. Establishing Standards for Side-by-Side Radiographic Comparisons.

    PubMed

    Ross, Ann H; Lanfear, Alicja K; Maxwell, Ashley B

    2016-06-01

    The objectives of this research were to evaluate the use of various anatomical features that are visible in standard radiographs and to develop a standard system of assessing concordant features for making positive identifications through radiographic comparison.The radiographs used in the study include craniofacial (n = 41), chest (n = 100), and proximal femur (n = 49), which were made available by the North Carolina Office of the Chief Medical Examiner. Radiographs were scored for number of concordant features and were analyzed using classification decision trees. The accuracy of the classification tree models was evaluated using a receiver operating characteristic.Two or more points of concordance are required in lateral cranial radiographs for a 97% probability of a positive identification. If more than 1 concordant feature exists on the cervical vertebrae, there is a 99% probability of correct identification. For thoracic and lumbar vertebrae, 4 or more concordant features are required for a 98% probability of correct identification. If there are 1 or more femoral head and neck concordant features, the probability of a correct identification is 94% and 97%, respectively. This study established the minimum number of concordant areas needed to confirm positive identifications in 3 standard radiographic views. PMID:26999427

  18. Radiographic measurement of internal organs in Spix's macaws (Cyanopsitta spixii).

    PubMed

    Rettmer, Helen; Deb, Amrita; Watson, Ryan; Hatt, Jean-Michel; Hammer, Sven

    2011-12-01

    Radiology is an important diagnostic instrument in avian medicine, but standard measurement ranges for the objective evaluation of radiographs of birds are rare. To establish radiographic reference ranges for the critically endangered Spix's macaw (Cyanopsitta spixii), we measured radiographic silhouettes of the heart, liver, kidneys, spleen, proventriculus, and keel of the sternum on 29 radiographs taken under standardized conditions in adult and juvenile, clinically healthy birds. Ratios were determined for the proventricular diameter-to-keel height, the width of the heart to the width of the thorax, and for the "hourglass shape" (ratio of the width of the heart to the width of the liver). No significant differences were found between the sexes among the adult birds. Compared with adult birds, juvenile females had a significantly larger heart width (19.8 +/- 1.4 mm versus 21.2 +/- 0.7 mm), ratio of the heart width to the thorax width (0.86 +/- 0.08 versus 0.94 +/- 0.09), and horizontal width of the spleen (7.7 +/- 0.6 mm versus 8.5 +/- 0.4 mm). Results of radiographic measurements in the Spix's macaws were comparable to those published from other psittacine species. These reference ranges will facilitate a more objective radiographic evaluation of captive Spix's macaws.

  19. Segmentation and determination of joint space width in foot radiographs

    NASA Astrophysics Data System (ADS)

    Schenk, O.; de Muinck Keizer, D. M.; Bernelot Moens, H. J.; Slump, C. H.

    2016-03-01

    Joint damage in rheumatoid arthritis is frequently assessed using radiographs of hands and feet. Evaluation includes measurements of the joint space width (JSW) and detection of erosions. Current visual scoring methods are timeconsuming and subject to inter- and intra-observer variability. Automated measurement methods avoid these limitations and have been fairly successful in hand radiographs. This contribution aims at foot radiographs. Starting from an earlier proposed automated segmentation method we have developed a novel model based image analysis algorithm for JSW measurements. This method uses active appearance and active shape models to identify individual bones. The model compiles ten submodels, each representing a specific bone of the foot (metatarsals 1-5, proximal phalanges 1-5). We have performed segmentation experiments using 24 foot radiographs, randomly selected from a large database from the rheumatology department of a local hospital: 10 for training and 14 for testing. Segmentation was considered successful if the joint locations are correctly determined. Segmentation was successful in only 14%. To improve results a step-by-step analysis will be performed. We performed JSW measurements on 14 randomly selected radiographs. JSW was successfully measured in 75%, mean and standard deviation are 2.30+/-0.36mm. This is a first step towards automated determination of progression of RA and therapy response in feet using radiographs.

  20. Digitization and postprocessing of plain-film radiographs for assessment of stone fragmentation after extracorporeal shockwave lithotripsy.

    PubMed

    Katzenwadel, A; Popken, G; Buitrago-Téllez, C H; Schultze-Seemann, W; Langer, M; Sommerkamp, H

    1995-12-01

    In 50 patients treated for urolithiasis by extracorporeal shockwave lithotripsy (ESWL++), the radiographs taken before and 1 day afterward were initially assessed by conventional radiography and subsequently after standardized digitization and postprocessing. Clinical outcome and passage of stone fragments were reevaluated 3 weeks after ESWL. Using specially developed software routines, new disintegration parameters could be obtained by detecting the number of relevant minima in light-intensity distribution along the length axis of the concrement in digitized images. Comparing the digitized images before with those after ESWL, the concremental surface and axial length in digitized images on average showed no statistically significant difference. However, the number of visually and automatically detected light-intensity minima of the concrement region in digitized images obtained 1 day after ESWL was significantly higher than prior to ESWL and correlated significantly with the number of fissure lines in the conventional images. These new features in digitized images showed a high sensitivity in predicting later passage of stone fragments. Moreover, in six of the seven patients without detectable fissure lines in the early conventional radiographs but obvious signs of concretemental disintegration 3 weeks after ESWL, there was an increase in the number of light-intensity minima in the digitized images 1 day after ESWL. Our findings indicate that this method of digitization and post-processing of radiographs may improve the assessment of ESWL effectiveness by improving standardization in the analysis of all surveyed parameters and by offering new relevant disintegration measures.

  1. X-ray physics- and bone composition-based estimation of thickness characteristics from clinical mandibular radiographs.

    PubMed

    Scheiner, Stefan; Hellmich, Christian; Müller, Christoph; Bonitz, Lars; Kober, Cornelia

    2015-10-01

    In dentistry, clinical radiographs (also called X-ray images) reflect the intensity loss of an X-ray when being transmitted through the mandibular objects, and this loss is quantified in terms of grey values. While such images are standardly used for pathology detection by the experienced dentist, we here present a new method for getting more quantitative information out of such 2D radiographs, "extending" them into the third dimension. This "extension" requires consistent combination of X-ray physics (namely, X-ray intensity loss quantification along paths orthogonal to the panoramic clinical image and X-ray attenuation averaging for composite materials) with anatomically known upper and lower limits of vascular porosities in cortical and trabecular bone compartments. Correspondingly computed ranges of overall organ thicknesses are extremely narrow, suggesting adequate estimation of thickness characteristics from 2D radiographic panoramas used clinically, while predicted cortical and trabecular thickness ranges vary by ±8.47% and ±16.13%, respectively. The proposed method also identifies variations between thicknesses at similar anatomical locations left and right of the face's symmetry axis, and molar regions turn out to be thicker than those close to incisors. This paves the way to more detailed diagnostic activities, e.g. in combination with Finite Element simulations. PMID:26253382

  2. Protocol of plain radiographs, hip ultrasound, and triple phase bone scans in the evaluation of the painful pediatric hip

    SciTech Connect

    Alexander, J.E.; Seibert, J.J.; Aronson, J.; Williamson, S.L.; Glasier, C.M.; Rodgers, A.B.; Corbitt, S.L.

    1988-04-01

    A useful protocol for the evaluation of hip pain in the pediatric patient, using a combination of plain radiographs, hip ultrasound (US), and triple phase radionuclide bone scans is presented. Patients with hip pain were initially evaluated by plain radiographs of the pelvis and hips. If no diagnosis was reached, the hips were studied for effusions by real-time hip ultrasonography. If an effusion was present, the joint was aspirated for diagnosis. If no effusion was present by US or if no diagnosis was reached by aspiration, triple phase radionuclide bone scans were performed. Fifty patients were evaluated by this prospective protocol, and the diagnosis was reached in 48 of the 50 cases (10 by plain radiographs, 16 by US, and aspiration of the joint, and 22 by triple phase bone scans). Hip effusions were found in 20 patients by US, with no false positives or false negatives. Previous studies for detecting effusions by US have emphasized absolute measurements of the capsular width, but we report a typical appearance of the hip capsule when fluid is present (a bulging convex capsule). When no effusion is present, the capsule is concave and parallels the long axis of the femoral neck.

  3. X-ray physics- and bone composition-based estimation of thickness characteristics from clinical mandibular radiographs.

    PubMed

    Scheiner, Stefan; Hellmich, Christian; Müller, Christoph; Bonitz, Lars; Kober, Cornelia

    2015-10-01

    In dentistry, clinical radiographs (also called X-ray images) reflect the intensity loss of an X-ray when being transmitted through the mandibular objects, and this loss is quantified in terms of grey values. While such images are standardly used for pathology detection by the experienced dentist, we here present a new method for getting more quantitative information out of such 2D radiographs, "extending" them into the third dimension. This "extension" requires consistent combination of X-ray physics (namely, X-ray intensity loss quantification along paths orthogonal to the panoramic clinical image and X-ray attenuation averaging for composite materials) with anatomically known upper and lower limits of vascular porosities in cortical and trabecular bone compartments. Correspondingly computed ranges of overall organ thicknesses are extremely narrow, suggesting adequate estimation of thickness characteristics from 2D radiographic panoramas used clinically, while predicted cortical and trabecular thickness ranges vary by ±8.47% and ±16.13%, respectively. The proposed method also identifies variations between thicknesses at similar anatomical locations left and right of the face's symmetry axis, and molar regions turn out to be thicker than those close to incisors. This paves the way to more detailed diagnostic activities, e.g. in combination with Finite Element simulations.

  4. Non abelian hydrodynamics and heavy ion collisions

    NASA Astrophysics Data System (ADS)

    Calzetta, E.

    2014-01-01

    The goal of the relativistic heavy ion collisions (RHIC) program is to create a state of matter where color degrees of freedom are deconfined. The dynamics of matter in this state, in spite of the complexities of quantum chromodynamics, is largely determined by the conservation laws of energy momentum and color currents. Therefore it is possible to describe its main features in hydrodynamic terms, the very short color neutralization time notwithstanding. In this lecture we shall give a simple derivation of the hydrodynamics of a color charged fluid, by generalizing the usual derivation of hydrodynamics from kinetic theory to the non abelian case.

  5. Nonlinear waves in second order conformal hydrodynamics

    NASA Astrophysics Data System (ADS)

    Fogaça, D. A.; Marrochio, H.; Navarra, F. S.; Noronha, J.

    2015-02-01

    In this work we study wave propagation in dissipative relativistic fluids described by a simplified set of the 2nd order viscous conformal hydrodynamic equations corresponding to Israel-Stewart theory. Small amplitude waves are studied within the linearization approximation while waves with large amplitude are investigated using the reductive perturbation method, which is generalized to the case of 2nd order relativistic hydrodynamics. Our results indicate the presence of a "soliton-like" wave solution in Israel-Stewart hydrodynamics despite the presence of dissipation and relaxation effects.

  6. Non abelian hydrodynamics and heavy ion collisions

    SciTech Connect

    Calzetta, E.

    2014-01-14

    The goal of the relativistic heavy ion collisions (RHIC) program is to create a state of matter where color degrees of freedom are deconfined. The dynamics of matter in this state, in spite of the complexities of quantum chromodynamics, is largely determined by the conservation laws of energy momentum and color currents. Therefore it is possible to describe its main features in hydrodynamic terms, the very short color neutralization time notwithstanding. In this lecture we shall give a simple derivation of the hydrodynamics of a color charged fluid, by generalizing the usual derivation of hydrodynamics from kinetic theory to the non abelian case.

  7. Hydrodynamic Instabilities Produced by Evaporation

    NASA Astrophysics Data System (ADS)

    Romo-Cruz, Julio Cesar Ruben; Hernandez-Zapata, Sergio; Ruiz-Chavarria, Gerardo

    2012-11-01

    When a liquid layer (alcohol in the present work) is in an environment where its relative humidity is less than 100 percent evaporation appears. When RH is above a certain threshold the liquid is at rest. If RH decreases below this threshold the flow becomes unstable, and hydrodynamic cells develop. The aim of this work is to understand the formation of those cells and its main features. Firstly, we investigate how the cell size depends on the layer width. We also study how temperature depends on the vertical coordinate when the cells are present. An inverse temperature gradient is found, that is, the bottom of liquid layer is colder than the free surface. This shows that the intuitive idea that the cells are due to a direct temperature gradient, following a Marangoni-like process, does not work. We propose the hypothesis that the evaporation produce a pressure gradient that is responsible of the cell development. On the other hand, using a Schlieren technique we study the topography of the free surface when cells are present. Finally the alcohol vapor layer adjacent to the liquid surface is explored using scattering experiments, giving some insight on the plausibility of the hypothesis described previously. Authors acknowledge support by DGAPA-UNAM under project IN116312 ``Vorticidad y ondas no lineales en fluidos.''

  8. Hydrodynamic Simulations of Contact Binaries

    NASA Astrophysics Data System (ADS)

    Kadam, Kundan; Clayton, Geoffrey C.; Frank, Juhan; Marcello, Dominic; Motl, Patrick M.; Staff, Jan E.

    2015-01-01

    The motivation for our project is the peculiar case of the 'red nova" V1309 Sco which erupted in September 2008. The progenitor was, in fact, a contact binary system. We are developing a simulation of contact binaries, so that their formation, structural, and merger properties could be studied using hydrodynamics codes. The observed transient event was the disruption of the secondary star by the primary, and their subsequent merger into one star; hence to replicate this behavior, we need a core-envelope structure for both the stars. We achieve this using a combination of Self Consistant Field (SCF) technique and composite polytropes, also known as bipolytropes. So far we have been able to generate close binaries with various mass ratios. Another consequence of using bipolytropes is that according to theoretical calculations, the radius of a star should expand when the core mass fraction exceeds a critical value, resulting in interesting consequences in a binary system. We present some initial results of these simulations.

  9. Hydrodynamic aspects of fish olfaction

    PubMed Central

    Cox, Jonathan P.L

    2008-01-01

    Flow into and around the olfactory chamber of a fish determines how odorant from the fish's immediate environment is transported to the sensory surface (olfactory epithelium) lining the chamber. Diffusion times in water are long, even over comparatively short distances (millimetres). Therefore, transport from the external environment to the olfactory epithelium must be controlled by processes that rely on convection (i.e. the bulk flow of fluid). These include the beating of cilia lining the olfactory chamber and the relatively inexpensive pumping action of accessory sacs. Flow through the chamber may also be induced by an external flow. Flow over the olfactory epithelium appears to be laminar. Odorant transfer to the olfactory epithelium may be facilitated in several ways: if the olfactory organs are mounted on stalks that penetrate the boundary layer; by the steep velocity gradients generated by beating cilia; by devices that deflect flow into the olfactory chamber; by parallel arrays of olfactory lamellae; by mechanical agitation of the chamber (or olfactory stalks); and by vortices. Overall, however, our knowledge of the hydrodynamics of fish olfaction is far from complete. Several areas of future research are outlined. PMID:18184629

  10. Detonation waves in relativistic hydrodynamics

    SciTech Connect

    Cissoko, M. )

    1992-02-15

    This paper is concerned with an algebraic study of the equations of detonation waves in relativistic hydrodynamics taking into account the pressure and the energy of thermal radiation. A new approach to shock and detonation wavefronts is outlined. The fluid under consideration is assumed to be perfect (nonviscous and nonconducting) and to obey the following equation of state: {ital p}=({gamma}{minus}1){rho} where {ital p}, {rho}, and {gamma} are the pressure, the total energy density, and the adiabatic index, respectively. The solutions of the equations of detonation waves are reduced to the problem of finding physically acceptable roots of a quadratic polynomial {Pi}({ital X}) where {ital X} is the ratio {tau}/{tau}{sub 0} of dynamical volumes behind and ahead of the detonation wave. The existence and the locations of zeros of this polynomial allow it to be shown that if the equation of state of the burnt fluid is known then the variables characterizing the unburnt fluid obey well-defined physical relations.

  11. ScaphoLunate Axis Method.

    PubMed

    Yao, Jeffrey; Zlotolow, Dan A; Lee, Steve K

    2016-03-01

    Background Treating chronic scapholunate ligament injuries without the presence of arthritis remains an unsolved clinical problem facing wrist surgeons. This article highlights a technique for reconstructing the scapholunate ligament using novel fixation, the ScaphoLunate Axis Method (SLAM). Materials and Methods In a preliminary review of the early experience of this technique, 13 patients were evaluated following scapholunate ligament reconstruction utilizing the SLAM technique. Description of Techinque The scapholunate interval is reconstructed utilizing a palmaris longus autograft passed between the scaphoid and lunate along the axis of rotation in the sagittal plane. It is secured in the lunate using a graft anchor and in the scaphoid utilizing an interference screw. The remaining graft is passed dorsally to reconstruct the dorsal scapholunate ligament. Results At an average follow-up of 11 months, the mean postoperative scapholunate gap was 2.1 mm. The mean postoperative scapholunate angle was 59 degrees. The mean postoperative wrist flexion and extension was 45 and 56 degrees, respectively. The mean grip strength was 24.9 kg, or 62% of the contralateral side. The mean pain score (VAS) was 1.7. There was 1 failure with recurrence of the pathologic scapholunate gap and the onset of pain. Conclusion While chronic scapholunate ligament instability remains an unsolved problem facing wrist surgeons, newer techniques are directed toward restoring the normal relationships of the scaphoid and lunate in both the coronal and sagittal planes. The SLAM technique has demonstrated promise in preliminary clinical studies. PMID:26855838

  12. Centration axis in refractive surgery.

    PubMed

    Arba Mosquera, Samuel; Verma, Shwetabh; McAlinden, Colm

    2015-01-01

    The human eye is an asymmetric optical system and the real cornea is not a rotationally symmetrical volume. Each optical element in the eye has its own optical and neural axes. Defining the optimum center for laser ablation is difficult with many available approaches. We explain the various centration approaches (based on these reference axes) in refractive surgery and review their clinical outcomes. The line-of-sight (LOS) (the line joining the entrance pupil center with the fixation point) is often the recommended reference axis for representing wavefront aberrations of the whole eye (derived from the definition of chief ray in geometrical optics); however pupil centration can be unstable and change with the pupil size. The corneal vertex (CV) represents a stable preferable morphologic reference which is the best approximate for alignment to the visual axis. However, the corneal light reflex can be considered as non-constant, but dependent on the direction of gaze of the eye with respect to the light source. A compromise between the pupil and CV centered ablations is seen in the form of an asymmetric offset where the manifest refraction is referenced to the CV while the higher order aberrations are referenced to the pupil center. There is a need for a flexible choice of centration in excimer laser systems to design customized and non-customized treatments optimally. PMID:26605360

  13. Flexible helical-axis stellarator

    DOEpatents

    Harris, Jeffrey H.; Hender, Timothy C.; Carreras, Benjamin A.; Cantrell, Jack L.; Morris, Robert N.

    1988-01-01

    An 1=1 helical winding which spirals about a conventional planar, circular central conductor of a helical-axis stellarator adds a significant degree of flexibility by making it possible to control the rotational transform profile and shear of the magnetic fields confining the plasma in a helical-axis stellarator. The toroidal central conductor links a plurality of toroidal field coils which are separately disposed to follow a helical path around the central conductor in phase with the helical path of the 1=1 winding. This coil configuration produces bean-shaped magnetic flux surfaces which rotate around the central circular conductor in the same manner as the toroidal field generating coils. The additional 1=1 winding provides flexible control of the magnetic field generated by the central conductor to prevent the formation of low-order resonances in the rotational transform profile which can produce break-up of the equilibrium magnetic surfaces. Further, this additional winding can deepen the magnetic well which together with the flexible control provides increased stability.

  14. Stress and the HPA Axis

    PubMed Central

    Stephens, Mary Ann C.; Wand, Gary

    2012-01-01

    Stress has long been suggested to be an important correlate of uncontrolled drinking and relapse. An important hormonal response system to stress—the hypothalamic–pituitary–adrenal (HPA) axis—may be involved in this process, particularly stress hormones known as glucocorticoids and primarily cortisol. The actions of this hormone system normally are tightly regulated to ensure that the body can respond quickly to stressful events and return to a normal state just as rapidly. The main determinants of HPA axis activity are genetic background, early-life environment, and current life stress. Alterations in HPA axis regulation are associated with problematic alcohol use and dependence; however, the nature of this dysregulation appears to vary with respect to stage of alcohol dependence. Much of this research has focused specifically on the role of cortisol in the risk for, development of, and relapse to chronic alcohol use. These studies found that cortisol can interact with the brain’s reward system, which may contribute to alcohol’s reinforcing effects. Cortisol also can influence a person’s cognitive processes, promoting habit-based learning, which may contribute to habit formation and risk of relapse. Finally, cortisol levels during abstinence may be useful clinical indicators of relapse vulnerability in alcohol-dependent people. PMID:23584113

  15. Maximum entropy principle and relativistic hydrodynamics

    NASA Astrophysics Data System (ADS)

    van Weert, Ch. G.

    1982-04-01

    A relativistic theory of hydrodynamics applicable beyond the hydrodynamic regime is developed on the basis of the maximum entropy principle. This allows the construction of a unique statistical operator representing the state of the system as specified by the values of the hydrodynamical densities. Special attention is paid to the thermodynamic limit and the virial theorem which leads to an expression for the pressure in terms of the field-theoretic energymomentum tensor of Coleman and Jackiw. It is argued that outside the hydrodynamic regime the notion of a local Gibbs relation, as usually postulated, must be abandoned in general. In the nontext of the linear approximation, the memory-retaining and non-local generalizations of the relativistic Navier-Stokes equations are derived from the underlying Heisenberg equations of motion. The formal similarity to the Zwanzig-Mori description of non-relativistic fluids is expounded.

  16. Hydrodynamic trapping of molecules in lipid bilayers

    PubMed Central

    Jönsson, Peter; McColl, James; Clarke, Richard W.; Ostanin, Victor P.; Jönsson, Bengt; Klenerman, David

    2012-01-01

    In this work we show how hydrodynamic forces can be used to locally trap molecules in a supported lipid bilayer (SLB). The method uses the hydrodynamic drag forces arising from a flow through a conical pipette with a tip radius of 1–1.5 μm, placed approximately 1 μm above the investigated SLB. This results in a localized forcefield that acts on molecules protruding from the SLB, yielding a hydrodynamic trap with a size approximately given by the size of the pipette tip. We demonstrate this concept by trapping the protein streptavidin, bound to biotin receptors in the SLB. It is also shown how static and kinetic information about the intermolecular interactions in the lipid bilayer can be obtained by relating how the magnitude of the hydrodynamic forces affects the accumulation of protein molecules in the trap. PMID:22699491

  17. Reliability and validity of Axis I of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) with proposed revisions.

    PubMed

    Look, J O; Schiffman, E L; Truelove, E L; Ahmad, M

    2010-10-01

      The research diagnostic criteria for temporomandibular disorders (RDC/TMD) have been employed internationally since 1992 for the study of temporomandibular muscle and joint disorders (TMD). This diagnostic protocol incorporates a dual system for assessment of TMD for Axis I physical diagnoses as well as Axis II psychological status and pain-related disability. Because the reliability and criterion validity of RDC/TMD had not yet been comprehensively characterised, the National Institute of Dental and Craniofacial Research funded in 2001 the most definitive research to date on the RDC/TMD as a U01 project entitled, 'Research Diagnostic Criteria: Reliability and Validity'. The results of this multi-site collaboration involving the University of Minnesota, the University of Washington, and the University at Buffalo were first reported at a pre-session workshop of the Toronto general session of the International Association of Dental Research on 2 July 2008. Summaries of five reports from this meeting are presented in this paper including: (i) reliability of RDC/TMD Axis I diagnoses based on clinical signs and symptoms; (ii) reliability of radiographic interpretations used for RDC/TMD Axis I diagnoses; (iii) reliability of self-report data used for RDC/TMD Axis I diagnoses; (iv) validity of RDC/TMD Axis I diagnoses based on clinical signs and symptoms; and (v) proposed revisions of the RDC/TMD Axis I diagnostic algorithms.

  18. Cervical Scoliosis: Clinical and Radiographic Outcomes

    PubMed Central

    Mesfin, Addisu; Bakhsh, Wajeeh R.; Chuntarapas, Tapanut; Riew, K. Daniel

    2015-01-01

    Study Design Retrospective study. Objective Cervical scoliosis is a rare condition that can arise from various etiologies. Few reports on the surgical management of cervical scoliosis exist. Our objective was to evaluate clinical and radiographic outcomes following surgical management of cervical scoliosis. Methods We evaluated our cervical spine surgical database for patients with cervical scoliosis (Cobb angle > 10 degrees) from 2005 to 2010. Demographic data including age, gender, diagnoses, and primary versus revision surgery was collected. Surgical data including procedure (anterior versus posterior), estimated blood loss (EBL), length of surgery, length of hospitalization, and complications was recorded. Preoperative and postoperative Cobb angle measurements and Neck Disability Index (NDI) scores were recorded. Results Cervical scoliosis was identified in 18 patients. We excluded 5, leaving 5 men and 8 women with an average age of 50.7 (median 52, range 25 to 65). The average follow-up was 40 months (median 36.5, range 5 to 87). An anterior-only approach was used in 6 cases (average 4 levels fused), 5 cases were posterior-only approach (average 8.7 levels fused), and 2 cases were combined anterior-posterior approach. The EBL was an average of 286 mL (median 150, range 50 to 900), the average surgical time was 266 minutes (median 239, range 136 to 508), and the average hospital stay was 2.7 days (median 2, range 1 to 7). Complications occurred in 7 patients, and 2 developed adjacent segment pathology. The average coronal Cobb angle preoperatively was 35.1 degrees (median 31, range 13 to 63) and corrected was 15.7 degrees (median 10.5, range 2 to 59) postoperatively (p < 0.005). The average NDI preoperatively was 24.9 (median 26, range 6 to 37) and was reduced to 17.8 (median 18, range 7 to 30) postoperatively (p < 0.02). Conclusion Surgical management of cervical scoliosis can result in deformity correction and improvement in patient

  19. Improvements to SOIL: An Eulerian hydrodynamics code

    SciTech Connect

    Davis, C.G.

    1988-04-01

    Possible improvements to SOIL, an Eulerian hydrodynamics code that can do coupled radiation diffusion and strength of materials, are presented in this report. Our research is based on the inspection of other Eulerian codes and theoretical reports on hydrodynamics. Several conclusions from the present study suggest that some improvements are in order, such as second-order advection, adaptive meshes, and speedup of the code by vectorization and/or multitasking. 29 refs., 2 figs.

  20. Flagellar Synchronization Independent of Hydrodynamic Interactions

    NASA Astrophysics Data System (ADS)

    Friedrich, Benjamin M.; Jülicher, Frank

    2012-09-01

    Inspired by the coordinated beating of the flagellar pair of the green algae Chlamydomonas, we study theoretically a simple, mirror-symmetric swimmer, which propels itself at low Reynolds number by a revolving motion of a pair of spheres. We show that perfect synchronization between these two driven spheres can occur due to the motion of the swimmer and local hydrodynamic friction forces. Hydrodynamic interactions, though crucial for net propulsion, contribute little to synchronization for this free-moving swimmer.

  1. Chemo-hydrodynamic patterns in porous media.

    PubMed

    De Wit, A

    2016-10-13

    Chemical reactions can interplay with hydrodynamic flows to generate chemo-hydrodynamic instabilities affecting the spatio-temporal evolution of the concentration of the chemicals. We review here such instabilities for porous media flows. We describe the influence of chemical reactions on viscous fingering, buoyancy-driven fingering in miscible systems, convective dissolution as well as precipitation patterns. Implications for environmental systems are discussed.This article is part of the themed issue 'Energy and the subsurface'. PMID:27597788

  2. Radiographic dental implants recognition for geographic evaluation in human identification.

    PubMed

    Nuzzolese, E; Lusito, S; Solarino, B; Di Vella, G

    2008-06-01

    Dental implants for prosthetic rehabilitation with fixed crown or mobile partial/total dentures is a very common oral treatment among the population in Italy as elsewhere. There is a great number of implant systems of different designs. However, a catalogue of radiographic images and a description of the dental implants available in Italy would be useful in order to identify the manufacturer and the type of implant encountered in forensic casework. When an unidentified body is found with one or more implants in the jaws, and no dental record is available, clues gleaned from the type of implants used could give direction to the investigation. In this study Italian implant manufactures were contacted and asked to provide specimen implants. Digital radiographs were taken of all the implants donated at 0º, 30º, and 60º horizontal rotation, combined with -20º, -10º, 0º, +10º, and +20º vertical inclination relative to the radiographic beam and the X-ray sensor. A total of 15 images per implant were taken and examined to identify consistent, unique features that would aid in implant recognition. Only those observations made from radiographs between -10º and +10º vertical inclination would ever be used for definite identification of any implant. The information from this study should be considered a survey of the commercial distribution of dental implants in Italy through their digital radiographic images. It is also a starting point for a wider geographical evaluation of different manufacturers in other countries and continents. The radiographic images provided should help both the forensic odontologist and the prosthodontist to identify pre-existing implants which they may discover from their radiographic images. PMID:22689351

  3. The hydrodynamic focusing effect inside rectangular microchannels

    NASA Astrophysics Data System (ADS)

    Lee, Gwo-Bin; Chang, Chih-Chang; Huang, Sung-Bin; Yang, Ruey-Jen

    2006-05-01

    This paper presents a theoretical and experimental investigation into the hydrodynamic focusing effect in rectangular microchannels. Two theoretical models for two-dimensional hydrodynamic focusing are proposed. The first model predicts the width of the focused stream in symmetric hydrodynamic focusing in microchannels of various aspect ratios. The second model predicts the location and the width of the focused stream in asymmetric hydrodynamic focusing in microchannels with a low or high aspect ratio. In both models, the theoretical results are shown to be in good agreement with the experimental data. Hence, the models provide a useful means of performing a theoretical analysis of flow control in microfluidic devices using hydrodynamic focusing effects. The ability of the proposed models to control the focused stream within a micro flow cytometer is verified in a series of experimental trials performed using polystyrene microparticles with a diameter of 20 µm. The experimental data show that the width of the focused stream can be reduced to the same order of magnitude as that of the particle size. Furthermore, it is shown that the microparticles can be successfully hydrodynamically focused and switched to the desired outlet port of the cytometer. Hence, the models presented in this study provide sufficient control to support cell/particle counting and sorting applications.

  4. A CT scan protocol for the detection of radiographic loosening of the glenoid component after total shoulder arthroplasty

    PubMed Central

    2014-01-01

    Background and purpose It is difficult to evaluate glenoid component periprosthetic radiolucencies in total shoulder arthroplasties (TSAs) using plain radiographs. This study was performed to evaluate whether computed tomography (CT) using a specific patient position in the CT scanner provides a better method for assessing radiolucencies in TSA. Methods Following TSA, 11 patients were CT scanned in a lateral decubitus position with maximum forward flexion, which aligns the glenoid orientation with the axis of the CT scanner. Follow-up CT scanning is part of our routine patient care. Glenoid component periprosthetic lucency was assessed according to the Molé score and it was compared to routine plain radiographs by 5 observers. Results The protocol almost completely eliminated metal artifacts in the CT images and allowed accurate assessment of periprosthetic lucency of the glenoid fixation. Positioning of the patient within the CT scanner as described was possible for all 11 patients. A radiolucent line was identified in 54 of the 55 observed CT scans and osteolysis was identified in 25 observations. The average radiolucent line Molé score was 3.4 (SD 2.7) points with plain radiographs and 9.5 (SD 0.8) points with CT scans (p = 0.001). The mean intra-observer variance was lower in the CT scan group than in the plain radiograph group (p = 0.001). Interpretation The CT scan protocol we used is of clinical value in routine assessment of glenoid periprosthetic lucency after TSA. The technique improves the ability to detect and monitor radiolucent lines and, therefore, possibly implant loosening also. PMID:24286563

  5. Study of geometrical effects on the characteristics of metallic double-walled carbon nanotube waveguides through quantum hydrodynamics

    SciTech Connect

    Ahmadizadeh, Y.; Javaherian, C.; Shokri, B.

    2009-06-15

    By assuming the metallic double-walled carbon nanotubes as two coaxial free electron gas layers with linearized hydrodynamic model, it is shown that surface plasmons coupled with electromagnetic fields can be excited on a metallic double-walled carbon nanotube and propagate along its axis. Dispersion relations of surface plasmons for E-type and B-type waves in various inner-outer radii and various interlayer distances for long metallic double-walled carbon nanotubes are obtained.

  6. Reassessing the standard chest radiograph for intraparenchymal activity

    SciTech Connect

    Putman, C.E.; Hoeck, B.

    1986-01-01

    The results concerning the activity or inactivity of the alveolitis determined with our proposed scoring system were comparable to those determined with gallium scanning in 68.2% of the patients with biopsy-proven sarcoidosis in our study. Certainly, further evaluation of a larger series of patients over a longer period of time will be required to more adequately evaluate this classification method. We also believe this methodology is reproducible and can be utilized by experienced interpreters of chest radiographs. If we closely reevaluate the 32% of the cases in which the radiographic results disagreed with the gallium assessment of activity, two points worthy of mention become evident. In one group the gallium indices were borderline for activity whereas in the other group the radiographic criteria were most likely indicative of irreversible parenchymal changes. When the radiographs for the latter group were reevaluated for signs of fibrosis such as volume loss, cystic changes, and alteration in vascular patterns, it was possible to delineate a significant false-positive group of patients. We will be reporting the long-term results of our observations over the next several years as well as adding more groups of patients to our initial study analysis. At that time, correlation with all other measurable parameters in determining high-intensity alveolitis versus low-intensity alveolitis will be compared to these new chest radiographic profiles.

  7. Radiologists remember mountains better than radiographs, or do they?

    PubMed

    Evans, Karla K; Marom, Edith M; Godoy, Myrna C B; Palacio, Diana; Sagebiel, Tara; Cuellar, Sonia Betancourt; McEntee, Mark; Tian, Charles; Brennan, Patrick C; Haygood, Tamara Miner

    2016-01-01

    Expertise with encoding material has been shown to aid long-term memory for that material. It is not clear how relevant this expertise is for image memorability (e.g., radiologists' memory for radiographs), and how robust over time. In two studies, we tested scene memory using a standard long-term memory paradigm. One compared the performance of radiologists to naïve observers on two image sets, chest radiographs and everyday scenes, and the other radiologists' memory with immediate as opposed to delayed recognition tests using musculoskeletal radiographs and forest scenes. Radiologists' memory was better than novices for images of expertise but no different for everyday scenes. With the heterogeneity of image sets equated, radiologists' expertise with radiographs afforded them better memory for the musculoskeletal radiographs than forest scenes. Enhanced memory for images of expertise disappeared over time, resulting in chance level performance for both image sets after weeks of delay. Expertise with the material is important for visual memorability but not to the same extent as idiosyncratic detail and variability of the image set. Similar memory decline with time for images of expertise as for everyday scenes further suggests that extended familiarity with an image is not a robust factor for visual memorability.

  8. SURGICAL CROWN LENGTHENING: A 12-MONTH STUDY - RADIOGRAPHIC RESULTS*

    PubMed Central

    Diniz, Daniela Eleutério; Okuda, Kalizia Marcela; Fonseca, Clarissa Ribeiro; Gonzalez, Marly Kimie Sonohara; Greghi, Sebastião Luiz Aguiar; do Valle, Accácio Lins; Lauris, José Roberto Pereira

    2007-01-01

    Objective The purpose of this study was to perform a radiographic follow-up evaluation after a 12-month healing period, following crown lengthening surgery. Material and methods Twenty-three periodontally healthy subjects (mean age 32.5 years) that required crown lengthening surgery in premolars were recruited. In a total of 30 premolars, full thickness flaps, osseous resection, and flap suturing were performed. The restorative margin was defined in the pre-surgical phase and maintained unaltered during the healing period, serving as a reference point. Standardized bitewing radiographs were taken before and after osseous reduction, and at 2, 3, 6, and 12-month healing periods. Results Intact lamina dura was observed at both mesial and distal alveolar crests only from the 3rd month. At 12-months, all alveolar crests presented lamina dura. The overall mean distance from the restorative margin to the alveolar crest achieved after osseous resection was 3.28±0.87 mm at mesial and 2.81±0.51 mm at distal sites. No significant radiographic changes in the bone crest were observed during a 12-month healing period. Conclusion The findings of this study suggest that the radiographic proximal bone level observed on bitewing radiographs following crown lengthening surgery can be used as a reference to predict the future level of the healed alveolar crest. PMID:19089145

  9. Radiologists remember mountains better than radiographs, or do they?

    PubMed

    Evans, Karla K; Marom, Edith M; Godoy, Myrna C B; Palacio, Diana; Sagebiel, Tara; Cuellar, Sonia Betancourt; McEntee, Mark; Tian, Charles; Brennan, Patrick C; Haygood, Tamara Miner

    2016-01-01

    Expertise with encoding material has been shown to aid long-term memory for that material. It is not clear how relevant this expertise is for image memorability (e.g., radiologists' memory for radiographs), and how robust over time. In two studies, we tested scene memory using a standard long-term memory paradigm. One compared the performance of radiologists to naïve observers on two image sets, chest radiographs and everyday scenes, and the other radiologists' memory with immediate as opposed to delayed recognition tests using musculoskeletal radiographs and forest scenes. Radiologists' memory was better than novices for images of expertise but no different for everyday scenes. With the heterogeneity of image sets equated, radiologists' expertise with radiographs afforded them better memory for the musculoskeletal radiographs than forest scenes. Enhanced memory for images of expertise disappeared over time, resulting in chance level performance for both image sets after weeks of delay. Expertise with the material is important for visual memorability but not to the same extent as idiosyncratic detail and variability of the image set. Similar memory decline with time for images of expertise as for everyday scenes further suggests that extended familiarity with an image is not a robust factor for visual memorability. PMID:26870748

  10. [Transparency regime: semiotics of radiographical images in urological diagnostics].

    PubMed

    Martin, M; Fangerau, H

    2012-10-01

    Shortly after Röntgen discovered x-rays urology became one of the main test fields for the application of this new technology. Initial scepticism among physicians, who were inclined to cling to traditional manual methods of diagnosing, was replaced by enthusiasm for radiographic technologies and the new method soon became the standard in, for example the diagnosis of concrements. Patients favoring radiographic procedures over the use of probes and a convincing documentation of stones in radiograms were factors that impacted the relatively rapid integration of radiology into urology. The radiographic representation of soft tissues and body cavities was more difficult and the development of contrast agents in particular posed a serious problem. Several patients died during this research. A new diagnostic dimension was revealed when radiography and cystography were combined to form the method of retrograde pyelography. However, the problem of how urologists could learn how to read the new images remained. In order to allow trainee physicians to practice interpreting radiograms atlases were produced which offered explanatory texts and drawings for radiographic images of the kidneys, the bladder etc. Thus, urologists developed a self-contained semiotics which facilitated the appropriation of a unique urological radiographical gaze.

  11. Differentiating Pneumothorax from the Common Radiographic Skinfold Artifact.

    PubMed

    Kattea, M Obadah; Lababede, Omar

    2015-06-01

    Pneumothorax can be a critical medical condition. The radiographic curvilinear appearance of pneumothorax can be mimicked by a skinfold artifact. Radiographic differentiation of the two entities is achieved in most cases by careful analysis of the characteristics of the linear shadow and its course. A thin, sharply defined opaque density representing the visceral pleura is the hallmark of pneumothorax. The added density of a skinfold presents as a broad opacity, which is outlined laterally by a sharply defined lucent line as a result of the Mach band effect and adjacent air. Unlike pneumothorax, a skinfold produces a line that does not follow the expected course of visceral pleura. Additional features, such as the absence of increased lucency laterally and the projection of lung markings across the curvilinear shadow, can help in the correct identification of skinfolds. Repeating the chest radiograph or using other imaging modalities can be considered in difficult cases.

  12. Osteochondroma of mandibular condyle: A clinic-radiographic correlation

    PubMed Central

    More, Chandramani B.; Gupta, Swati

    2013-01-01

    Osteochondroma (OC) of temporo mandibular joint is a rare, slow growing, benign tumor that causes a progressive enlargement of the condyle, usually resulting in facial asymmetry, temporo mandibular joint (TMJ) dysfunction, limited mouth opening and malocclusion. Pain is rarely associated with this tumor. OC is composed of cartilaginous and osseous tissues. Radiographically, there is unilaterally enlarged condyle usually with an exophytic outgrowth of the tumor from the condylar head. We present a rare case of osteochondroma of right mandibular condyle in a 45-year-old male who reported with painless swelling over TMJ area and progressive limited mouth opening. Panoramic radiograph and computed tomography (CT) was performed for better evaluation of the pathological condition. This paper describes the clinico-radiographic features and differential diagnosis of OC. PMID:24082753

  13. Comparisons of NIF convergent ablation simulations with radiograph data.

    PubMed

    Olson, R E; Hicks, D G; Meezan, N B; Koch, J A; Landen, O L

    2012-10-01

    A technique for comparing simulation results directly with radiograph data from backlit capsule implosion experiments will be discussed. Forward Abel transforms are applied to the kappa*rho profiles of the simulation. These provide the transmission ratio (optical depth) profiles of the simulation. Gaussian and top hat blurs are applied to the simulated transmission ratio profiles in order to account for the motion blurring and imaging slit resolution of the experimental measurement. Comparisons between the simulated transmission ratios and the radiograph data lineouts are iterated until a reasonable backlighter profile is obtained. This backlighter profile is combined with the blurred, simulated transmission ratios to obtain simulated intensity profiles that can be directly compared with the radiograph data. Examples will be shown from recent convergent ablation (backlit implosion) experiments at the NIF.

  14. Cemented total hip prosthesis: Radiographic and scintigraphic evaluation

    SciTech Connect

    Aliabadi, P.; Tumeh, S.S.; Weissman, B.N.; McNeil, B.J. )

    1989-10-01

    Conventional radiographs, technetium-99m bone scans, and gallium-67 scans were reviewed in 44 patients who had undergone cemented total hip joint replacement and were imaged because of suspicion of prosthesis loosening or infection. A complete radiolucent line of 2 mm or wider along the bone-cement interface or metal-cement lucency on conventional radiographs was used as the criterion for prosthetic loosening with or without infection and proved to be 54% sensitive and 96% specific. Scintigraphic criteria for prosthetic loosening were increased focal uptake of the radiopharmaceutical for the femoral component and increased focal or diffuse uptake for the acetabular component. For bone scintigraphy, sensitivity was 73% and specificity was 96%. Combining the results of conventional radiographs and bone scans increased sensitivity to 84% and decreased specificity to 92% for the diagnosis of loosening, infection, or both. The study also showed that Ga-67 scintigraphy has a low sensitivity for the detection of infection.

  15. Radiographic results of an accelerometer-based, handheld surgical navigation system for the tibial resection in total knee arthroplasty.

    PubMed

    Nam, Denis; Cross, Michael; Deshmane, Prashant; Jerabek, Seth; Kang, Michael; Mayman, David J

    2011-10-05

    In total knee arthroplasty (TKA), intramedullary and extramedullary tibial alignment guides are not proven to be highly accurate in obtaining alignment perpendicular to the mechanical axis in the coronal plane. The objective of this study was to determine the accuracy of an accelerometer-based, handheld surgical navigation system in obtaining a postoperative tibial component alignment within 2° of the intraoperative goal in both the coronal and sagittal planes. A total of 151 TKAs were performed by 2 surgeons using a handheld surgical navigation system to perform the tibial resection. Postoperatively, standing anteroposterior hip-to-ankle radiographs and lateral knee-to-ankle radiographs were performed to determine the varus/valgus alignment and the posterior slope of the tibial components relative to the mechanical axis in both the coronal and sagittal planes. Findings showed that 95.3% of the tibial components were placed within 2° of the intraoperative goal in the coronal plane and 96.1% of the components were placed within 2° of the intraoperative goal in the sagittal plane. Overall, mean postoperative lower-extremity alignment was -0.3°±2.1°, with 97% of patients having an alignment within 3° of a neutral mechanical axis. The handheld surgical navigation system improves the accuracy of the tibial resection and subsequent tibial component alignment in TKA. It is able to combine the accuracy of computer-assisted surgery systems with the ease of use and familiarity of conventional, extramedullary alignment systems, and the ability to adjust both the coronal and sagittal alignments intraoperatively may prove clinically useful in TKA.

  16. Prediction of osteoporosis using dental radiographs and age in females

    PubMed Central

    Vijay, Guduba; Chitroda, Parita K.; Katti, Girish; Shahbaz, Syed; Baba, Irfan; Bhuvaneshwari

    2015-01-01

    Aims and Objectives: To evaluate the role of dental radiograph as a screening tool for diagnosis of osteoporosis in females. Materials and Methods: In the present study, 50 women between the age group of 40-60 were recruited, and patients with systemic disorder and taking calcium supplements, and women who are not willing for investigation were excluded. Their detailed medical history was obtained and dental radiographs were made, bone mineral density was measured at left radial bone using ultrasound. The radiographs were subjected to image analysis method using manual tracing of gonial angle, antegonial angle, antegonial depth, antegonial index, mental index and mandibular cortical index. Statistical discrimination analysis was applied to predict the presence of osteoporosis. With use of these indices, the sensitivity and specificity of orthopantomograph (OPG) radiograph to assess age-related changes in bone were compared. Radiomorphometric indices (RMI) were also scrutinized to depict the sensitivity and specificity of each index in the prediction of osteoporosis. Results: Study results showed no significant differences between bone mineral density (BMD) and radiomorphometric analysis in the diagnoses of osteoporotic females. Out of 29, diagnosed as osteoporotic by radiograph 23 were confirmed by BMD and six were diagnosed as osteopenic. Among the six indices used, AGA and AGD showed more reproducible results. Conclusion: With our study results, we come to an arrival that OPG radiographs show overall sensitivity of 0.75 or 75% and specificity of 0.81 or 81% in the diagnosis of osteoporosis, and that anti gonial angle (AGA) and anti gonial depth (AGD) are the most reliable indices. Hence, we conclude that panoramic-based RMI can be used as an ancillary method in the diagnosis of osteoporosis. PMID:26167057

  17. Mechanical axis of the lower extremity determined by a new digital photographic method.

    PubMed

    Simonsen, Ole Højgaard; Thomsen, Hanne; Skou, Søren Thorgaard; Andersen, Mikkel Meyer

    2013-08-01

    Assessment of the mechanical axis is routine during the examination of patients with lower extremity pain. Long-leg radiographic examination is the gold standard for exact measurement, but it is associated with a significant radiation dose. An alternative method to examine the mechanical axis has been warranted. This article validates a newly developed computerized photograph method to calculate the mechanical axis using a digital photograph. The location of the center of the femoral head was calculated using ink marks on both superior iliac spines. Twenty-five patients (10 women and 15 men) had both legs examined using the photographic method and long-leg radiography examination. The digital photograph method was found to be highly reliable. The interobserver absolute mean difference was 0.99°±0.85°, and the intraobserver absolute mean difference (day-to-day variation) was 1.04°±0.81°. The mechanical axis determined by the 2 methods was highly correlated (R=0.943). The long-leg radiography method was within an average of ±1.88° of the photographic method, with a 95% probability. The photographic method appears to be an effective alternative to conventional long-leg radiography. The photographic method seems convenient in the routine examination of patients with leg pain and children with suspected axial deformity and for follow-up after treatment for malalignment. Calculation coefficients for children and a possible racial difference remain to be studied.

  18. A numerical method of tracing a vortical axis along local topological axis line

    NASA Astrophysics Data System (ADS)

    Nakayama, Katsuyuki; Hasegawa, Hideki

    2016-06-01

    A new numerical method is presented to trace or identify a vortical axis in flow, which is based on Galilean invariant flow topology. We focus on the local flow topology specified by the eigenvalues and eigenvectors of the velocity gradient tensor, and extract the axis component from its flow trajectory. Eigen-vortical-axis line is defined from the eigenvector of the real eigenvalue of the velocity gradient tensor where the tensor has the conjugate complex eigenvalues. This numerical method integrates the eigen-vortical-axis line and traces a vortical axis in terms of the invariant flow topology, which enables to investigate the feature of the topology-based vortical axis.

  19. Helical axis stellarator with noninterlocking planar coils

    DOEpatents

    Reiman, Allan; Boozer, Allen H.

    1987-01-01

    A helical axis stellarator using only noninterlocking planar, non-circular coils, generates magnetic fields having a magnetic well and large rotational transform with resultant large equilibrium beta.

  20. Principles of the prolactin/vasoinhibin axis

    PubMed Central

    Bertsch, Thomas; Bollheimer, Cornelius; Rios-Barrera, Daniel; Pearce, Christy F.; Hüfner, Michael; Martínez de la Escalera, Gonzalo; Clapp, Carmen

    2015-01-01

    The hormonal family of vasoinhibins, which derive from the anterior pituitary hormone prolactin, are known for their inhibiting effects on blood vessel growth, vasopermeability, and vasodilation. As pleiotropic hormones, vasoinhibins act in multiple target organs and tissues. The generation, secretion, and regulation of vasoinhibins are embedded into the organizational principle of an axis, which integrates the hypothalamus, the pituitary, and the target tissue microenvironment. This axis is designated as the prolactin/vasoinhibin axis. Disturbances of the prolactin/vasoinhibin axis are associated with the pathogenesis of retinal and cardiac diseases and with diseases occurring during pregnancy. New phylogenetical, physiological, and clinical implications are discussed. PMID:26310939

  1. Principles of the prolactin/vasoinhibin axis.

    PubMed

    Triebel, Jakob; Bertsch, Thomas; Bollheimer, Cornelius; Rios-Barrera, Daniel; Pearce, Christy F; Hüfner, Michael; Martínez de la Escalera, Gonzalo; Clapp, Carmen

    2015-11-15

    The hormonal family of vasoinhibins, which derive from the anterior pituitary hormone prolactin, are known for their inhibiting effects on blood vessel growth, vasopermeability, and vasodilation. As pleiotropic hormones, vasoinhibins act in multiple target organs and tissues. The generation, secretion, and regulation of vasoinhibins are embedded into the organizational principle of an axis, which integrates the hypothalamus, the pituitary, and the target tissue microenvironment. This axis is designated as the prolactin/vasoinhibin axis. Disturbances of the prolactin/vasoinhibin axis are associated with the pathogenesis of retinal and cardiac diseases and with diseases occurring during pregnancy. New phylogenetical, physiological, and clinical implications are discussed.

  2. New formulation of leading order anisotropic hydrodynamics

    NASA Astrophysics Data System (ADS)

    Tinti, Leonardo

    2015-05-01

    Anisotropic hydrodynamics is a reorganization of the relativistic hydrodynamics expansion, with the leading order already containing substantial momentum-space anisotropies. The latter are a cause of concern in the traditional viscous hydrodynamics, since large momentum anisotropies generated in ultrarelativistic heavy-ion collisions are not consistent with the hypothesis of small deviations from an isotropic background, i.e., from the local equilibrium distribution. We discuss the leading order of the expansion, presenting a new formulation for the (1+1)- dimensional case, namely, for the longitudinally boost invariant and cylindrically symmetric flow. This new approach is consistent with the well established framework of Israel and Stewart in the close to equilibrium limit (where we expect viscous hydrodynamics to work well). If we consider the (0+1)-dimensional case, that is, transversally homogeneous and longitudinally boost invariant flow, the new form of anisotropic hydrodynamics leads to better agreement with known solutions of the Boltzmann equation than the previous formulations, especially when we consider massive particles.

  3. Hydrodynamic modulation of pluripotent stem cells

    PubMed Central

    2012-01-01

    Controlled expansion and differentiation of pluripotent stem cells (PSCs) using reproducible, high-throughput methods could accelerate stem cell research for clinical therapies. Hydrodynamic culture systems for PSCs are increasingly being used for high-throughput studies and scale-up purposes; however, hydrodynamic cultures expose PSCs to complex physical and chemical environments that include spatially and temporally modulated fluid shear stresses and heterogeneous mass transport. Furthermore, the effects of fluid flow on PSCs cannot easily be attributed to any single environmental parameter since the cellular processes regulating self-renewal and differentiation are interconnected and the complex physical and chemical parameters associated with fluid flow are thus difficult to independently isolate. Regardless of the challenges posed by characterizing fluid dynamic properties, hydrodynamic culture systems offer several advantages over traditional static culture, including increased mass transfer and reduced cell handling. This article discusses the challenges and opportunities of hydrodynamic culture environments for the expansion and differentiation of PSCs in microfluidic systems and larger-volume suspension bioreactors. Ultimately, an improved understanding of the effects of hydrodynamics on the self-renewal and differentiation of PSCs could yield improved bioprocessing technologies to attain scalable PSC culture strategies that will probably be requisite for the development of therapeutic and diagnostic applications. PMID:23168068

  4. On the definition of discrete hydrodynamic variables.

    PubMed

    Español, Pep; Zúñiga, Ignacio

    2009-10-28

    The Green-Kubo formula for discrete hydrodynamic variables involves information about not only the fluid transport coefficients but also about discrete versions of the differential operators that govern the evolution of the discrete variables. This gives an intimate connection between discretization procedures in fluid dynamics and coarse-graining procedures used to obtain hydrodynamic behavior of molecular fluids. We observed that a natural definition of discrete hydrodynamic variables in terms of Voronoi cells leads to a Green-Kubo formula which is divergent, rendering the full coarse-graining strategy useless. In order to understand this subtle issue, in the present paper we consider the coarse graining of noninteracting Brownian particles. The discrete hydrodynamic variable for this problem is the number of particles within Voronoi cells. Thanks to the simplicity of the model we spot the origin of the singular behavior of the correlation functions. We offer an alternative definition, based on the concept of a Delaunay cell that behaves properly, suggesting the use of the Delaunay construction for the coarse graining of molecular fluids at the discrete hydrodynamic level.

  5. Hydrodynamics in Holocene Lake Mega-Chad

    NASA Astrophysics Data System (ADS)

    Bouchette, Frédéric; Schuster, Mathieu; Ghienne, Jean-François; Denamiel, Cléa; Roquin, Claude; Moussa, Abderamane; Marsaleix, Patrick; Duringer, Philippe

    2010-03-01

    Holocene Lake Mega-Chad (LMC) was the largest late Quaternary water-body in Africa. The development of this giant paleo-lake is related to a northward shift of the isohyetes interpreted as evidence for an enhanced Monsoon (African Humid Period). Numerous preserved coastal features have been described all around the LMC shore. Such features reveal the main paleo-hydrodynamical tendencies. In the context of a closed water-body like LMC, hydrodynamics are forced mainly by winds. We use a three-dimensional numerical model (SYMPHONIE) to simulate the mean hydrodynamics in LMC under both Harmattan-like (northeasterly trade winds) and Monsoon-like (southwesterly winds) forcings. The northern part of LMC displays coastal features, such as sand spits, that are consistent with the simulations forced by Harmattan-like winds. Geomorphic features related to Monsoon-driven hydrodynamics are not clearly expressed. They could have developed during the early stage of LMC but subsequently reworked. At the time of sand-spit building, Harmattan-like driven hydrodynamics prevailed and related coastal features were preferentially preserved in the sedimentary record.

  6. Scaling supernova hydrodynamics to the laboratory

    SciTech Connect

    Kane, J O; Remington, B A; Arnett, D; Fryxell, B A; Drake, R P

    1998-11-10

    Supernova (SN) 1987A focused attention on the critical role of hydrodynamic instabilities in the evolution of supernovae. To test the modeling of these instabilities, they are attempting to rigorously scale the physics of the laboratory in supernova. The scaling of hydrodynamics on microscopic laser scales to hydrodynamics on the SN-size scales is presented and requirements established. Initial results were reported in [1]. Next the appropriate conditions are generated on the NOVA laser. 10-15 Mbar shock at the interface of a two-layer planar target, which triggers perturbation growth, due to the Richtmyer-Meshkov instability and to the Rayleigh-Taylor instability as the interface decelerates is generated. This scales the hydrodynamics of the He-H interface of a Type II supernova at intermediate times, up to a few x10{sup 3} s. The experiment is modeled using the hydrodynamics codes HYADES and CALE, and the supernova code PROMETHEUS. Results of the experiments and simulations are presented. Analysis of the spike bubble velocities using potential flow theory and Ott thin shell theory is presented, as well as a study of 2D vs. 3D difference in growth at the He-H interface of Sn 1987A.

  7. Hydrodynamic approaches in relativistic heavy ion reactions

    NASA Astrophysics Data System (ADS)

    Derradi de Souza, R.; Koide, T.; Kodama, T.

    2016-01-01

    We review several facets of the hydrodynamic description of the relativistic heavy ion collisions, starting from the historical motivation to the present understandings of the observed collective aspects of experimental data, especially those of the most recent RHIC and LHC results. In this report, we particularly focus on the conceptual questions and the physical foundations of the validity of the hydrodynamic approach itself. We also discuss recent efforts to clarify some of the points in this direction, such as the various forms of derivations of relativistic hydrodynamics together with the limitations intrinsic to the traditional approaches, variational approaches, known analytic solutions for special cases, and several new theoretical developments. Throughout this review, we stress the role of course-graining procedure in the hydrodynamic description and discuss its relation to the physical observables through the analysis of a hydrodynamic mapping of a microscopic transport model. Several questions to be answered to clarify the physics of collective phenomena in the relativistic heavy ion collisions are pointed out.

  8. Theoretical Analysis of Radiographic Images by Nonstationary Poisson Processes

    NASA Astrophysics Data System (ADS)

    Tanaka, Kazuo; Yamada, Isao; Uchida, Suguru

    1980-12-01

    This paper deals with the noise analysis of radiographic images obtained in the usual fluorescent screen-film system. The theory of nonstationary Poisson processes is applied to the analysis of the radiographic images containing the object information. The ensemble averages, the autocorrelation functions, and the Wiener spectrum densities of the light-energy distribution at the fluorescent screen and of the film optical-density distribution are obtained. The detection characteristics of the system are evaluated theoretically. Numerical examples of the one-dimensional image are shown and the results are compared with those obtained under the assumption that the object image is related to the background noise by the additive process.

  9. Skeletal metastases of melanoma: radiographic, scintigraphic, and clinical review

    SciTech Connect

    Fon, G.T.; Wong, W.S.; Gold, R.H.; Kaiser, L.R.

    1981-07-01

    The radiographic manifestations of 127 skeletal metastases in 50 patients with melanoma were reviewed and correlated with the scintigraphic findings. Although the features of most of the metastases were nonspecific and appeared similar to those of other osteolytic metastases, several of them had unusual features, including expansion, subarticular location, osteosclerosis, and a thin, sclerotic rim. These features could result in some of the metastases being mistaken for other lesions. The radionuclide bone scans were more sensitive in that they detected the lesions earlier and in greater numbers than the radiographs. Prognosis was poor once skeletal metastasis was diagnosed, the mean survival time being 4.7 months.

  10. Ultrasonic and radiographic evaluation of advanced aerospace materials: Ceramic composites

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R.

    1990-01-01

    Two conventional nondestructive evaluation techniques were used to evaluate advanced ceramic composite materials. It was shown that neither ultrasonic C-scan nor radiographic imaging can individually provide sufficient data for an accurate nondestructive evaluation. Both ultrasonic C-scan and conventional radiographic imaging are required for preliminary evaluation of these complex systems. The material variations that were identified by these two techniques are porosity, delaminations, bond quality between laminae, fiber alignment, fiber registration, fiber parallelism, and processing density flaws. The degree of bonding between fiber and matrix cannot be determined by either of these methods. An alternative ultrasonic technique, angular power spectrum scanning (APSS) is recommended for quantification of this interfacial bond.

  11. Hydrodynamics of a unitary Bose gas

    NASA Astrophysics Data System (ADS)

    Man, Jay; Fletcher, Richard; Lopes, Raphael; Navon, Nir; Smith, Rob; Hadzibabic, Zoran

    2016-05-01

    In general, normal-phase Bose gases are well described by modelling them as ideal gases. In particular, hydrodynamic flow is usually not observed in the expansion dynamics of normal gases, and is more readily observable in Bose-condensed gases. However, by preparing strongly-interacting clouds, we observe hydrodynamic behaviour in normal-phase Bose gases, including the `maximally' hydrodynamic unitary regime. We avoid the atom losses that often hamper experimental access of this regime by using radio-frequency injection, which switches on interactions much faster than trap or loss timescales. At low phase-space densities, we find excellent agreement with a collisional model based on the Boltzmann equation. At higher phase-space densities our results show a deviation from this model in the vicinity of an Efimov resonance, which cannot be accounted for by measured losses.

  12. 17. Local Characteristic Algorithms for Relativistic Hydrodynamics

    NASA Astrophysics Data System (ADS)

    Font, Jose A.

    Numerical schemes for the general relativistic hydrodynamic equations are discussed. The use of conservative algorithms based upon the characteristic structure of those equations, developed during the last decade building on ideas first applied in Newtonian hydrodynamics, provides a robust methodology to obtain stable and accurate solutions even in the presence of discontinuities. The knowledge of the wave structure of the above system is essential in the construction of the so-called linearized Riemann solvers, a class of numerical schemes specifically designed to solve nonlinear hyperbolic systems of conservation laws. In the last part of the review some astrophysical applications of such schemes, using the coupled system of the (characteristic) Einstein and hydrodynamic equations, are also briefly presented.

  13. A hydrodynamic approach to cosmology - Methodology

    NASA Technical Reports Server (NTRS)

    Cen, Renyue

    1992-01-01

    The present study describes an accurate and efficient hydrodynamic code for evolving self-gravitating cosmological systems. The hydrodynamic code is a flux-based mesh code originally designed for engineering hydrodynamical applications. A variety of checks were performed which indicate that the resolution of the code is a few cells, providing accuracy for integral energy quantities in the present simulations of 1-3 percent over the whole runs. Six species (H I, H II, He I, He II, He III) are tracked separately, and relevant ionization and recombination processes, as well as line and continuum heating and cooling, are computed. The background radiation field is simultaneously determined in the range 1 eV to 100 keV, allowing for absorption, emission, and cosmological effects. It is shown how the inevitable numerical inaccuracies can be estimated and to some extent overcome.

  14. Toward a Fully Consistent Radiation Hydrodynamics

    SciTech Connect

    Castor, J I

    2009-07-07

    Dimitri Mihalas set the standard for all work in radiation hydrodynamics since 1984. The present contribution builds on 'Foundations of Radiation Hydrodynamics' to explore the relativistic effects that have prevented having a consistent non-relativistic theory. Much of what I have to say is in FRH, but the 3-D development is new. Results are presented for the relativistic radiation transport equation in the frame obtained by a Lorentz boost with the fluid velocity, and the exact momentum-integrated moment equations. The special-relativistic hydrodynamic equations are summarized, including the radiation contributions, and it is shown that exact conservation is obtained, and certain puzzles in the non-relativistic radhydro equations are explained.

  15. On the hydrodynamics of swimming enzymes

    NASA Astrophysics Data System (ADS)

    Bai, Xiaoyu; Wolynes, Peter G.

    2015-10-01

    Several recent experiments suggest that rather generally the diffusion of enzymes may be augmented through their activity. We demonstrate that such swimming motility can emerge from the interplay between the enzyme energy landscape and the hydrodynamic coupling of the enzyme to its environment. Swimming thus occurs during the transit time of a transient allosteric change. We estimate the velocity during the transition. The analysis of such a swimming motion suggests the final stroke size is limited by the hydrodynamic size of the enzyme. This limit is quite a bit smaller than the values that can be inferred from the recent experiments. We also show that one proposed explanation of the experiments based on reaction heat effects can be ruled out using an extended hydrodynamic analysis. These results lead us to propose an alternate explanation of the fluorescence correlation measurements.

  16. Dynamo efficiency controlled by hydrodynamic bistability.

    PubMed

    Miralles, Sophie; Herault, Johann; Herault, Johann; Fauve, Stephan; Gissinger, Christophe; Pétrélis, François; Daviaud, François; Dubrulle, Bérengère; Boisson, Jean; Bourgoin, Mickaël; Verhille, Gautier; Odier, Philippe; Pinton, Jean-François; Plihon, Nicolas

    2014-06-01

    Hydrodynamic and magnetic behaviors in a modified experimental setup of the von Kármán sodium flow-where one disk has been replaced by a propeller-are investigated. When the rotation frequencies of the disk and the propeller are different, we show that the fully turbulent hydrodynamic flow undergoes a global bifurcation between two configurations. The bistability of these flow configurations is associated with the dynamics of the central shear layer. The bistable flows are shown to have different dynamo efficiencies; thus for a given rotation rate of the soft-iron disk, two distinct magnetic behaviors are observed depending on the flow configuration. The hydrodynamic transition controls the magnetic field behavior, and bifurcations between high and low magnetic field branches are investigated. PMID:25019895

  17. Hydrodynamic stellar interactions in dense star clusters

    NASA Technical Reports Server (NTRS)

    Rasio, Frederic A.

    1993-01-01

    Highly detailed HST observations of globular-cluster cores and galactic nuclei motivate new theoretical studies of the violent dynamical processes which govern the evolution of these very dense stellar systems. These processes include close stellar encounters and direct physical collisions between stars. Such hydrodynamic stellar interactions are thought to explain the large populations of blue stragglers, millisecond pulsars, X-ray binaries, and other peculiar sources observed in globular clusters. Three-dimensional hydrodynamics techniques now make it possible to perform realistic numerical simulations of these interactions. The results, when combined with those of N-body simulations of stellar dynamics, should provide for the first time a realistic description of dense star clusters. Here I review briefly current theoretical work on hydrodynamic stellar interactions, emphasizing its relevance to recent observations.

  18. Heat transfer and hydrodynamics analysis of a novel dimpled tube

    SciTech Connect

    Wang, Yu.; He, Ya-Ling; Lei, Yong-Gang; Zhang, Jie

    2010-11-15

    In the present investigation, heat transfer and hydrodynamics analysis of a new enhanced heat transfer tube with ellipsoidal dimples was carried out. The dimples are disposed to form a certain specified angle between the major axis of the ellipsoid and flow direction, and the direction of the major axis of each adjacent ellipsoidal dimple in the same cross-section is alternated. Experimental tests were carried out with heating water on the shell side with a constant flow rate, and cold air in the tube side with flow rates range from 1 to 55 m{sup 3}/h. The temperatures and pressures for the inlet and outlet of both sides were measured. The heat transfer and pressure drop of the new dimpled tube were investigated and compared with the results of a dimpled tube with spherical dimples and a conventional smooth tube. The computed results indicated that the Nusselt number for ellipsoidal dimpled tube and spherical dimpled tube are 38.6-175.1% and 34.1-158% higher than that for the smooth tube respectively. The friction factors of dimpled tube increase by 26.9-75% and 32.9-92% for ellipsoidal and spherical dimples compared with the smooth tube respectively. It was perceived that ellipsoidal dimple roughness accelerates transition to critical Reynolds numbers down to less than 1000. By integrated performance evaluation of (Nu{sub a}/Nu{sub s})/(f{sub a}/f{sub s}), a maximum of about 87% heat transfer enhancement with the same friction penalty could be achieved by optimize the dimpled tube design. (author)

  19. Integration of hydrodynamic interactions between filaments

    NASA Astrophysics Data System (ADS)

    Man, Yi; Lauga, Eric

    2015-11-01

    In many biological situations, slender filaments interact through a viscous fluid, and these hydrodynamic interactions play a crucial cellular role. Examples include the ability of peritrichous bacteria to bundle their flagella or the generation of metachronal waves in cilia arrays. In most cases of interest, three distinct length scales characterize the filaments, their typical thickness a, relative distance h, and length L, which are asymptotically separated as a << h << L . In this talk, we demonstrate how to analytically develop a long-wavelength integration of hydrodynamic singularities in this biologically-relevant limit.

  20. Supernova hydrodynamics experiments using the Nova laser

    SciTech Connect

    Remington, B.A.; Glendinning, S.G.; Estabrook, K.; Wallace, R.J.; Rubenchik, A.; Kane, J.; Arnett, D.; Drake, R.P.; McCray, R.

    1997-04-01

    We are developing experiments using the Nova laser to investigate two areas of physics relevant to core-collapse supernovae (SN): (1) compressible nonlinear hydrodynamic mixing and (2) radiative shock hydrodynamics. In the former, we are examining the differences between the 2D and 3D evolution of the Rayleigh-Taylor instability, an issue critical to the observables emerging from SN in the first year after exploding. In the latter, we are investigating the evolution of a colliding plasma system relevant to the ejecta-stellar wind interactions of the early stages of SN remnant formation. The experiments and astrophysical implications are discussed.

  1. Shadowfax: Moving mesh hydrodynamical integration code

    NASA Astrophysics Data System (ADS)

    Vandenbroucke, Bert

    2016-05-01

    Shadowfax simulates galaxy evolution. Written in object-oriented modular C++, it evolves a mixture of gas, subject to the laws of hydrodynamics and gravity, and any collisionless fluid only subject to gravity, such as cold dark matter or stars. For the hydrodynamical integration, it makes use of a (co-) moving Lagrangian mesh. The code has a 2D and 3D version, contains utility programs to generate initial conditions and visualize simulation snapshots, and its input/output is compatible with a number of other simulation codes, e.g. Gadget2 (ascl:0003.001) and GIZMO (ascl:1410.003).

  2. Concentrating solar cookers with eccentric axis

    SciTech Connect

    Wang Xiping; Sha Yong Ling; Hou Shugin; Liu Zude

    1992-12-31

    This paper describes the design, development and use of a concentrating solar cooker with eccentric axis in China. For the same power, the older circular parabolic cookers are large in volume and less convenient to operate than the cooker with eccentric axis. Calculations are presented for the design of the cooker and for obtaining an accurate test of its efficiency.

  3. Thermal neutron image intensifier tube provides brightly visible radiographic pattern

    NASA Technical Reports Server (NTRS)

    Berger, H.; Kraska, I.; Niklas, W.; Schmidt, A.

    1967-01-01

    Vacuum-type neutron image intensifier tube improves image detection in thermal neutron radiographic inspection. This system converts images to an electron image, and with electron acceleration and demagnification between the input target and output screen, produces a bright image viewed through a closed circuit television system.

  4. Reliable Radiographic Inspection of Flexible Risers for the Oil Industry

    NASA Astrophysics Data System (ADS)

    Almeida, Rômulo M.; Rebello, Joao Marcos A.; Vaz, Murilo A.

    2010-02-01

    Flexible risers are composite tubular structures manufactured by the concentric assemblage of cylindrical polymeric and helically wound metallic layers employed to convey pressurized fluids such as oil, gas and water in the ocean environment. The metallic layers account for the flexible risers' structural strength and are dimensioned according to the static and dynamic loads. They are usually installed in a free hanging catenary configuration and are subjected to the direct action of waves and marine currents and wave induced motions from the oil production platform. The fatigue rupture of wire armours in the end fitting or within the riser segment protected by the bend stiffener is an object of major concern. Integrity models have been developed, however inspection techniques are mandatory to ensure that failure is detected. Gammagraphy has been used as a common inspection technique in all regions of the flexible riser, mainly with the single wall-single view method. On the other side, there is not any qualified radiographic procedure to this kind of structure. Radiographic simulation was adopted and its validation with actual gammagraphies and establishment of radiographic parameters to complex radiation geometries were done. Results show the viability of the radiographic inspection analyzing the armour wires' rupture and the displacement between wires.

  5. Assessment of radiation protection practices among radiographers in Lagos, Nigeria

    PubMed Central

    Eze, Cletus Uche; Abonyi, Livinus Chibuzo; Njoku, Jerome; Irurhe, Nicholas Kayode; Olowu, Oluwabola

    2013-01-01

    Background: Use of ionising radiation in diagnostic radiography could lead to hazards such as somatic and genetic damages. Compliance to safe work and radiation protection practices could mitigate such risks. The aim of the study was to assess the knowledge and radiation protection practices among radiographers in Lagos, Nigeria. Materials and Methods: The study was a prospective cross sectional survey. Convenience sampling technique was used to select four x-ray diagnostic centres in four tertiary hospitals in Lagos metropolis. Data were analysed with Epi- info software, version 3.5.1. Results: Average score on assessment of knowledge was 73%. Most modern radiation protection instruments were lacking in all the centres studied. Application of shielding devices such as gonad shield for protection was neglected mostly in government hospitals. Most x-ray machines were quite old and evidence of quality assurance tests performed on such machines were lacking. Conclusion: Radiographers within Lagos metropolis showed an excellent knowledge of radiation protection within the study period. Adherence to radiation protection practices among radiographers in Lagos metropolis during the period studied was, however, poor. Radiographers in Lagos, Nigeria should embrace current trends in radiation protection and make more concerted efforts to apply their knowledge in protecting themselves and patients from harmful effects of ionising radiation. PMID:24665152

  6. Information content of low-dose radiographs: Part 2

    SciTech Connect

    Morris, R.A.

    1997-10-01

    The previous paper described the concept of using the net number of information bits transmitted in a radiographic image as a measure of the contrast parameter of image quality. The concept is particularly useful when the image contrast is limited by the statistics of the photon fluence incident on the detector (low doses). The Wolfram Research Mathematica program (described in Ref. 1) that was used to simulate a noisy image of an object with two thicknesses and to calculate the resulting IC (information content). The only noise source in the simulation was fluctuations in the photon fluence incident on the detector. The results from the simulation were compared to data obtained from actual radiographs of a copper step wedge radiographed with 10 and 50 pulses from a 150-p, V x-ray machine. Good agreement between the simulation and experiment was obtained when the photon fluence was considered a free, adjustable parameter. This report extends the simulation described in Ref. 1 and shows how IC varies as the following radiographic parameters change: object thickness; object Z number; x-ray energy; and incident x-ray fluence.

  7. PHERMEX: Pulsed High-Energy Radiographic Machine Emitting X rays

    SciTech Connect

    Dick, R.D.

    1981-01-01

    The PHERMEX facility used to provide flash radiographs of explosives and explosive-driven metal systems is described. With this facility, precision radiographs of large objects containing materials with high atomic number and high density are attainable. PHERMEX encompasses the high-current, three-cavity, 30-MeV linear electron accelerator; the 50-MHz-radiofrequency power source to drive the cavities; timing, firing, and signal detection system; and a data-acquisition system. Some unique features of PHERMEX are reliability; very intensive submicrosecond bremsstrahlung source rich in 4- to 8-MeV x rays; less than 1.0-mm-diam spot size; precision determination of edges, discontinuities, and areal-mass distribution; and flash radiographs of large explosive systems close to the x-ray target. Some aspects of the PHERMEX-upgrading program are discussed. The program will result (1) in an increased electron-beam energy to about 50 MeV, (2) the use of an electron-gun pulser that is capable of producing three time-adjustable pulses for obtaining three radiographic pictures of a single explosive event, (3) an increased electron injection energy of 1.25 MeV, (4) the capability for recording high-speed signals, and (5) the use of computers to assist the monitoring and control of the data-acquisition system and the PHERMEX accelerator.

  8. Radiographic appearance of commonly used cements in implant dentistry.

    PubMed

    Pette, Gregory A; Ganeles, Jeffrey; Norkin, Frederic J

    2013-01-01

    Cement-retained restorations allow for a conventional fixed partial denture approach to restoring dental implants. However, inadequate removal of excess cement at the time of cementation may introduce a severe complication: cement-induced peri-implantitis. Radiopaque cements are more easily detected on radiographs and should improve the recognition of extravasated cement at the time of insertion. The purpose of this study was to evaluate the radiopacity of commercially available cements in vitro. Eighteen different cements commonly used for luting restorations to implants were tested at both 0.5- and 1.0-mm thicknesses. The cements examined were zinc oxide eugenol, zinc oxide, zinc polycarboxylate, zinc phosphate, resin-reinforced glass ionomer, urethane resin, resin, and composite resin. Two samples of each cement thickness underwent standardized radiography next to an aluminum step wedge as a reference. The mean grayscale value of each of the nine 1-mm steps in the step wedge were used as reference values and compared to each of the cement samples. Temp Bond Clear (resin), IMProv (urethane resin), Premier Implant Cement (resin), and Temrex NE (resin) were not radiographically detectable at either sample thickness. Cements containing zinc were the most detectable upon radiographic analysis. There are significant differences in the radiopacity of many commonly used cements. Since cementinduced peri-implantitis can lead to late implant failure, cements that can be visualized radiographically may reduce the incidence of this problem.

  9. Computer Simulation Of Radiographic Screen-Film Images

    NASA Astrophysics Data System (ADS)

    Metter, Richard V.; Dillon, Peter L.; Huff, Kenneth E.; Rabbani, Majid

    1986-06-01

    A method is described for computer simulation of radiographic screen-film images. This method is based on a previously published model of the screen-film imaging process.l The x-ray transmittance of a test object is sampled at a pitch of 50 μm by scanning a high-resolution, low-noise direct-exposure radiograph. This transmittance is then used, along with the x-ray exposure incident upon the object, to determine the expected number of quanta per pixel incident upon the screen. The random nature of x-ray arrival and absorption, x-ray quantum to light photon conversion, and photon absorption by the film is simulated by appropriate random number generation. Standard FFT techniques are used for computing the effects of scattering. Finally, the computed film density for each pixel is produced on a high-resolution, low-noise output film by a scanning printer. The simulation allows independent specification of x-ray exposure, x-ray quantum absorption, light conversion statistics, light scattering, and film characteristics (sensitometry and gran-ularity). Each of these parameters is independently measured for radiographic systems of interest. The simulator is tested by comparing actual radiographic images with simulated images resulting from the independently measured parameters. Images are also shown illustrating the effects of changes in these parameters on image quality. Finally, comparison is made with a "perfect" imaging system where information content is only limited by the finite number of x-rays.

  10. Optical versus radiographic magnification for fine-detail skeletal radiography.

    PubMed

    Genant, H K; Doi, K; Mall, J C

    1975-01-01

    Fine-detail radiographic techniques for peripheral skeletal imaging have gained wide clinical acceptance. In this study, the imaging properties and clinical applications of the optical magnification technique, which employs fine-grain industrial film and a large focal spot, are compared quantitatively and qualitatively with those of three slow screen-film techniques, namely, contact exposure with a large focal spot, 2 times radiographic magnification with a 0.3 mm focal spot, and 4 times radiographic magnification with a 50 mu focal spot. The modulation transfer functions (MTF's) of the recording systems and focal spots are obtained and film sensitometry performed. Clinical comparisons are made for patients with metabolic, arthritic, and neoplastic skeletal disorders. The results illustrate the superiority of the optical magnification technique over contact or 2 times magnification techniques using slow screen-film systems. If a microfocus tube is used, however, direct radiographic magnification may provide images comparable in resolution, noise and contrast to those made with the optical magnification technique, and at lower radiation exposure to the patient. PMID:46857

  11. Radiographic skills learning: procedure simulation using adaptive hypermedia.

    PubMed

    Costaridou, L; Panayiotakis, G; Pallikarakis, N; Proimos, B

    1996-10-01

    The design and development of a simulation tool supporting learning of radiographic skills is reported. This tool has by textual, graphical and iconic resources, organized according to a building-block, adaptive hypermedia approach, which is described and supported by an image base of radiographs. It offers interactive user-controlled simulation of radiographic imaging procedures. The development is based on a commercially available environment (Toolbook 3.0, Asymetrix Corporation). The core of the system is an attributed precedence (priority) graph, which represents a task outline (concept and resources structure), which is dynamically adjusted to selected procedures. The user interface imitates a conventional radiography system, i.e. operating console, tube, table, patient and cassette. System parameters, such as patient positioning, focus-to-patient distance, magnification, field dimensions, tube voltage and mAs are under user control. Their effects on image quality are presented, by means of an image base acquired under controlled exposure conditions. Innovative use of hypermedia, computer based learning and simulation principles and technology in the development of this tool resulted in an enhanced interactive environment providing radiographic parameter control and visualization of parameter effects on image quality. PMID:9038530

  12. CHARACTERIZATION OF THE ADVANCED RADIOGRAPHIC CAPABILITY FRONT END ON NIF

    SciTech Connect

    Haefner, C; Heebner, J; Dawson, J; Fochs, S; Shverdin, M; Crane, J K; Kanz, V K; Halpin, J; Phan, H; Sigurdsson, R; Brewer, W; Britten, J; Brunton, G; Clark, W; Messerly, M J; Nissen, J D; Nguyen, H; Shaw, B; Hackel, R; Hermann, M; Tietbohl, G; Siders, C W; Barty, C J

    2009-07-15

    We have characterized the Advanced Radiographic Capability injection laser system and demonstrated that it meets performance requirements for upcoming National Ignition Facility fusion experiments. Pulse compression was achieved with a scaled down replica of the meter-scale grating ARC compressor and sub-ps pulse duration was demonstrated at the Joule-level.

  13. Localized Fisher vector representation for pathology detection in chest radiographs

    NASA Astrophysics Data System (ADS)

    Geva, Ofer; Lieberman, Sivan; Konen, Eli; Greenspan, Hayit

    2016-03-01

    In this work, we present a novel framework for automatic detection of abnormalities in chest radiographs. The representation model is based on the Fisher Vector encoding method. In the representation process, we encode each chest radiograph using a set of extracted local descriptors. These include localized texture features that address typical local texture abnormalities as well as spatial features. Using a Gaussian Mixture Model, a rich image descriptor is generated for each chest radiograph. An improved representation is obtained by selection of features that correspond to the relevant region of interest for each pathology. Categorization of the X-ray images is conducted using supervised learning and the SVM classifier. The proposed system was tested on a dataset of 636 chest radiographs taken from a real clinical environment. We measured the performance in terms of area (AUC) under the receiver operating characteristic (ROC) curve. Results show an AUC value of 0.878 for abnormal mediastinum detection, and AUC values of 0.827 and 0.817 for detection of right and left lung opacities, respectively. These results improve upon the state-of-the-art as compared with two alternative representation models.

  14. Analysis of physiological impact while reading stereoscopic radiographs

    NASA Astrophysics Data System (ADS)

    Unno, Yasuko Y.; Tajima, Takashi; Kuwabara, Takao; Hasegawa, Akira; Natsui, Nobutaka; Ishikawa, Kazuo; Hatada, Toyohiko

    2011-03-01

    A stereoscopic viewing technology is expected to improve diagnostic performance in terms of reading efficiency by adding one more dimension to the conventional 2D images. Although a stereoscopic technology has been applied to many different field including TV, movies and medical applications, physiological fatigue through reading stereoscopic radiographs has been concerned although no established physiological fatigue data have been provided. In this study, we measured the α-amylase concentration in saliva, heart rates and normalized tissue hemoglobin index (nTHI) in blood of frontal area to estimate physiological fatigue through reading both stereoscopic radiographs and the conventional 2D radiographs. In addition, subjective assessments were also performed. As a result, the pupil contraction occurred just after the reading of the stereoscopic images, but the subjective assessments regarding visual fatigue were nearly identical for the reading the conventional 2D and stereoscopic radiographs. The α-amylase concentration and the nTHI continued to decline while examinees read both 2D and stereoscopic images, which reflected the result of subjective assessment that almost half of the examinees reported to feel sleepy after reading. The subjective assessments regarding brain fatigue showed that there were little differences between 2D and stereoscopic reading. In summary, this study shows that the physiological fatigue caused by stereoscopic reading is equivalent to the conventional 2D reading including ocular fatigue and burden imposed on brain.

  15. Automatic Evaluation of Welded Joints Using Image Processing on Radiographs

    NASA Astrophysics Data System (ADS)

    Schwartz, Ch.

    2003-03-01

    Radiography is frequently used to detect discontinuities in welded joints (porosity, cracks, lack of penetration). Perfect knowledge of the geometry of these defects is an important step which is essential to appreciate the quality of the weld. Because of this, an action improving the interpretation of radiographs by image processing has been undertaken. The principle consists in making a radiograph of the welded joint and of a depth step wedge penetrameter in the material. The radiograph is then finely digitized and an automatic processing of the radiograph of the penetrameter image allows the establishment of a correspondence between grey levels and material thickness. An algorithm based on image processing is used to localize defects in the welded joints and to isolate them from the original image. First, defects detected by this method are characterized in terms of dimension and equivalent thickness. Then, from the image of the healthy welded joint (that is to say without the detected defects), characteristic values of the weld are evaluated (thickness reduction, width).

  16. 21 CFR 892.1950 - Radiographic anthropomorphic phantom.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... purposes to simulate a human body for positioning radiographic equipment. (b) Classification. Class I... Section 892.1950 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... good manufacturing practice requirements of the quality system regulation in part 820 of this...

  17. 21 CFR 892.1950 - Radiographic anthropomorphic phantom.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... purposes to simulate a human body for positioning radiographic equipment. (b) Classification. Class I... Section 892.1950 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... good manufacturing practice requirements of the quality system regulation in part 820 of this...

  18. Radiographer Delivered Fluoroscopy Reduces Radiation Exposure During Endoscopic Urological Procedures

    PubMed Central

    Hennessey, DB; Young, M; Pahuja, A

    2016-01-01

    Introduction The 1999 Ionising Radiation Regulations recommend that medical professionals using ionising radiation should aim to keep exposure as ‘low as reasonably practicable’. Urologists regularly use fluoroscopy during endoscopic surgical procedures. In some institutions, this is delivered by a radiographer whereas in others, it is delivered by the urological surgeon. Objectives To determine if radiographer-delivered fluoroscopy can reduce the exposure to ionising radiation during urological procedures. Methods An analysis of 395 consecutive patients, who underwent endoscopic urological procedures requiring fluoroscopy, was performed simultaneously across two institutions, over a 4 month period. 321 patients were matched and included in the analysis. Results Radiographer delivered fluoroscopy was associated with reduced ionising radiation exposure for retrograde pyelography procedures ED 0.09626 vs. 1.323 mSev, p= 0.0003, and endoscopic stone surgeries ED 0.3066 Vs. 0.5416 mSev, p=0.0039, but not for ureterorenoscopic stone surgeries 0.4880 vs. 0.2213 mSev, p=0.8292. Conclusion Radiographer delivered fluoroscopy could reduce the patient’s exposure to ionising radiation for some urological procedures. PMID:27158158

  19. Digital correction of computed X-radiographs for coral densitometry

    NASA Astrophysics Data System (ADS)

    Boucher, H.; Duprey, N.; Jiménez, C.

    2011-12-01

    Corals are widely used for environmental and climatic changes assessment as their skeletal growth is influenced by the surrounding environment. Variations in skeletal density are sensitive to environmental variations (water temperature, nutrients concentration etc.). Digitized X-radiographs have been used for coral skeleton density measurements since the 1980s. However, the shape of the X-ray beam emitted during the irradiation process is strongly distorted due to spherical spreading (inverse square law) and heel effect. Consequently, the X-ray intensity intersecting the surface of the sensitive film or the electronic sensor (e.g. PSL plate) is heterogeneous. These heterogeneities are characterized by an asymmetrical concentric pattern of decreasing intensity from the center to the edges of the X-radiographs. It commonly generates an error on density measurements that may reach up to 40%. This is twice as much as the seasonal density variations that are usually found in corals. Until now, extra X-ray images or aluminum standards were used to correct X-radiographs. Such corrective methods may be constraining when working with a high number of coral samples. We present an inexpensive, straightforward, and accurate method to correct strong heterogeneities of X-ray irradiation that affect X-ray images. The method relies on the relation between optical density (OD) and skeletal density; it is non-destructive, and provides high-resolution measurements. Our method was applied to measure density variations on Caribbean reef-building coral Siderastrea siderea from Costa Rica. The basic assumption is that the X-radiograph background, i.e., areas without objects, records the asymmetrical concentric pattern of X-ray intensity. A full image of this pattern was created with a natural neighbor interpolation. The resulting modeled image was then subtracted from the original X-ray image, permitting thus a reliable OD measurement directly on the corrected X-ray image. This Digital

  20. Radiographic diagnosis of dental restoration misfit: a systematic review.

    PubMed

    Liedke, G S; Spin-Neto, R; da Silveira, H E D; Wenzel, A

    2014-12-01

    The objective of this study was to perform a systematic review on the use of radiographic methods for the diagnosis of misfit in dental prostheses and restorations. The MEDLINE bibliographic database was searched from 1950 to February 2014 for reports on the radiographic diagnosis of misfits. The search strategy was limited to English-language publications using the following combined MeSH terms in the search strategy: (Dental Restoration OR Dental Prosthesis OR Crown OR Inlays OR Dental Abutments) and (Dental Leakage OR Prosthesis Fitting OR Dental Marginal Adaptation OR Surface Properties) and (Radiography, Dental OR Radiography, Dental, Digital OR Cone-Beam Computed Tomography). Twenty-eight publications were identified and read in full text, and 14 studies fulfilled criteria for inclusion. Information regarding the use of radiographic methods for the diagnosis of misfits in dental prosthesis and restorations, and in which the methodology/results comprised information regarding how the sample was collected/prepared, the method, imaging protocol, presence of a reference test and the outcomes were evaluated. QUADAS criteria was used to rate the studies in high, moderate or low quality. The evidence supporting the use of radiographic methods for the diagnosis of misfits in dental prosthesis and restorations is limited to low-/moderate-quality studies. The well-established intra-oral orthogonal projection is still under investigation and considered the most appropriate method, both when evaluating the relation between dental restoration to tooth and abutment to implant. Studies using digital radiographs have not evaluated the effect of image post-processing, and tomography has not been evaluated. PMID:25142004

  1. Radiographic diagnosis of dental restoration misfit: a systematic review.

    PubMed

    Liedke, G S; Spin-Neto, R; da Silveira, H E D; Wenzel, A

    2014-12-01

    The objective of this study was to perform a systematic review on the use of radiographic methods for the diagnosis of misfit in dental prostheses and restorations. The MEDLINE bibliographic database was searched from 1950 to February 2014 for reports on the radiographic diagnosis of misfits. The search strategy was limited to English-language publications using the following combined MeSH terms in the search strategy: (Dental Restoration OR Dental Prosthesis OR Crown OR Inlays OR Dental Abutments) and (Dental Leakage OR Prosthesis Fitting OR Dental Marginal Adaptation OR Surface Properties) and (Radiography, Dental OR Radiography, Dental, Digital OR Cone-Beam Computed Tomography). Twenty-eight publications were identified and read in full text, and 14 studies fulfilled criteria for inclusion. Information regarding the use of radiographic methods for the diagnosis of misfits in dental prosthesis and restorations, and in which the methodology/results comprised information regarding how the sample was collected/prepared, the method, imaging protocol, presence of a reference test and the outcomes were evaluated. QUADAS criteria was used to rate the studies in high, moderate or low quality. The evidence supporting the use of radiographic methods for the diagnosis of misfits in dental prosthesis and restorations is limited to low-/moderate-quality studies. The well-established intra-oral orthogonal projection is still under investigation and considered the most appropriate method, both when evaluating the relation between dental restoration to tooth and abutment to implant. Studies using digital radiographs have not evaluated the effect of image post-processing, and tomography has not been evaluated.

  2. Radiographic liver size in Pekingese dogs versus other dog breeds.

    PubMed

    Choi, Jihye; Keh, Seoyeon; Kim, Hyunwook; Kim, Junyoung; Yoon, Junghee

    2013-01-01

    Differential diagnoses for canine liver disease are commonly based on radiographic estimates of liver size, however little has been published on breed variations. Aims of this study were to describe normal radiographic liver size in Pekingese dogs and to compare normal measurements for this breed with other dog breeds and Pekingese dogs with liver disease. Liver measurements were compared for clinically normal Pekingese (n = 61), normal non-Pekingese brachycephalic (n = 45), normal nonbrachycephalic (n = 71), and Pekingese breed dogs with liver disease (n = 22). For each dog, body weight, liver length, T11 vertebral length, thoracic depth, and thoracic width were measured on right lateral and ventrodorsal abdominal radiographs. Liver volume was calculated using a formula and ratios of liver length/T11 vertebral length and liver volume/body weight ratio were determined. Normal Pekingese dogs had a significantly smaller liver volume/body weight ratio (16.73 ± 5.67, P < 0.05) than normal non-Pekingese brachycephalic breed dogs (19.54 ± 5.03) and normal nonbrachycephalic breed dogs (18.72 ± 6.52). The liver length/T11 vertebral length ratio in normal Pekingese (4.64 ± 0.65) was significantly smaller than normal non-Pekingese brachycephalic breed dogs (5.16 ± 0.74) and normal nonbrachycephalic breed dogs (5.40 ± 0.74). Ratios of liver volume/body weight and liver length/T11 vertebral length in normal Pekingese were significantly different from Pekingese with liver diseases (P < 0.05). Findings supported our hypothesis that Pekingese dogs have a smaller normal radiographic liver size than other breeds. We recommend using 4.64× the length of the T11 vertebra as a radiographic criterion for normal liver length in Pekingese dogs.

  3. Microinstability of the Hip and the Splits Radiograph.

    PubMed

    Harris, Joshua D; Gerrie, Brayden J; Lintner, David M; Varner, Kevin E; McCulloch, Patrick C

    2016-01-01

    A normal hip has a natural tendency toward stability because of both osseous and soft tissue structures. Hip motion is primarily rotational around a center of rotation. When the femoral head and its center of rotation translate, with or without rotation, the inherent stability of the femoroacetabular articulation may be lost. The spectrum of hip instability ranges from subtle microinstability to traumatic dislocation. Microinstability may be the cause or the effect of several other hip pathologies. Soft tissue contributions to stability include the static capsule, dynamic musculotendinous units, and underlying generalized connective tissue (eg, Ehlers-Danlos). Osseous contributions include multiple femoral and acetabular radiographic coverage parameters. Iatrogenic contributions include an unrepaired capsulotomy, overresection of the acetabular rim (iatrogenic dysplasia), overresection of cam osteochondroplasty, iliopsoas tenotomy, labral debridement, and ligamentum teres debridement. Patients with hip microinstability often have deep groin pain, exhibited by a C sign. These patients frequently participate in flexibility sports and activities, such as ballet, gymnastics, figure skating, and martial arts. On physical examination, generalized hypermobility syndromes should be assessed, as should loss of log-roll external rotation recoil, excessive abduction, trochanteric-pelvic impingement, and abductor fatigue. Standard imaging, including plain radiographs, magnetic resonance imaging, and computed tomography, should be analyzed for all causes of hip pain. A new plain radiograph, the splits radiograph is introduced here, consistently showing lateral femoral head translation and creation of a vacuum sign, showing hip microinstability. The splits radiograph is illustrated in a 22-year-old female dancer who presented with bilateral deep anterolateral groin pain. PMID:26730687

  4. Hydrodynamic Force on a Cylinder Oscillating at Low Frequency

    NASA Technical Reports Server (NTRS)

    Berg, Robert F.; Yao, Minwu; Panzarella, Charles H.

    2007-01-01

    The hydrodynamic force on a cylinder oscillating transversely to its axis is a nonlinear function of the displacement amplitude x0. We report measurements and numerical calculations of the force at frequencies low enough that delta > R, where delta is the viscous penetration length and R is the cylinder radius. For small amplitudes, the numerically calculated Fourier transform of the force per unit length, F(sub small), agrees with Stokes' analytical calculation. For larger amplitudes, the force per unit length found by both calculation and measurement is F = F(sub small)C (x(sub 0)/delta,R/delta). The complex function C depends only weakly on R/delta, indicating that x0/delta is more appropriate as a scaling variable than the Keulegan-Carpenter number KC = pi*x(sub 0)/R. The measurements used a torsion oscillator driven at frequencies from 1 to 12 Hz while immersed in dense xenon. The oscillator comprised cylinders with an effective radius of R = 13.4 micron and oscillation amplitudes as large as x(sub 0)/delta = 4 (corresponding to KC as large as 71). The calculations used similar conditions except that the amplitudes were as large as x0/delta = 28.

  5. Circumstellar Hydrodynamics and Spectral Radiation in ALGOLS

    NASA Astrophysics Data System (ADS)

    Terrell, Dirk Curtis

    1994-01-01

    Algols are the remnants of binary systems that have undergone large scale mass transfer. This dissertation presents the results of the coupling of a hydrodynamical model and a radiative model of the flow of gas from the inner Lagrangian point. The hydrodynamical model is a fully Lagrangian, three-dimensional scheme with a novel treatment of viscosity and an implementation of the smoothed particle hydrodynamics method to compute pressure gradients. Viscosity is implemented by allowing particles within a specified interaction length to share momentum. The hydrodynamical model includes a provision for computing the self-gravity of the disk material, although it is not used in the present application to Algols. Hydrogen line profiles and equivalent widths computed with a code by Drake and Ulrich are compared with observations of both short and long period Algols. More sophisticated radiative transfer computations are done with the escape probability code of Ko and Kallman which includes the spectral lines of thirteen elements. The locations and velocities of the gas particles, and the viscous heating from the hydro program are supplied to the radiative transfer program, which computes the equilibrium temperature of the gas and generates its emission spectrum. Intrinsic line profiles are assumed to be delta functions and are properly Doppler shifted and summed for gas particles that are not eclipsed by either star. Polarization curves are computed by combining the hydro program with the Wilson-Liou polarization program. Although the results are preliminary, they show that polarization observations show great promise for studying circumstellar matter.

  6. Stabilizing geometry for hydrodynamic rotary seals

    DOEpatents

    Dietle, Lannie L.; Schroeder, John E.

    2010-08-10

    A hydrodynamic sealing assembly including a first component having first and second walls and a peripheral wall defining a seal groove, a second component having a rotatable surface relative to said first component, and a hydrodynamic seal comprising a seal body of generally ring-shaped configuration having a circumference. The seal body includes hydrodynamic and static sealing lips each having a cross-sectional area that substantially vary in time with each other about the circumference. In an uninstalled condition, the seal body has a length defined between first and second seal body ends which varies in time with the hydrodynamic sealing lip cross-sectional area. The first and second ends generally face the first and second walls, respectively. In the uninstalled condition, the first end is angulated relative to the first wall and the second end is angulated relative to the second wall. The seal body has a twist-limiting surface adjacent the static sealing lip. In the uninstalled condition, the twist-limiting surface is angulated relative to the peripheral wall and varies along the circumference. A seal body discontinuity and a first component discontinuity mate to prevent rotation of the seal body relative to the first component.

  7. Hydrodynamic dispersion of microswimmers in suspension

    NASA Astrophysics Data System (ADS)

    Martin, Matthieu; Rafaï, Salima; Peyla, Philippe

    2014-11-01

    In our laboratory, we study hydrodynamics of suspensions of micro-swimmers. These micro-organisms are unicellular algae Chlamydomonas Rheinhardii which are able to swim by using their flagella. The swimming dynamics of these micro-swimmers can be seen as a random walk, in absence of any kind of interaction. In addition, these algae have the property of being phototactic, i.e. they swim towards the light. Combining this property with a hydrodynamic flow, we were able to reversibly separate algae from the rest of the fluid. But for sufficiently high volume fraction, these active particles interact with each other. We are now interested in how the coupling of hydrodynamic interactions between swimmers and phototaxis can modify the swimming dynamics at the scale of the suspension. To this aim, we conduct experiments in microfluidic devices to study the dispersion of the micro-organisms in a the liquid phase as a function of the volume fraction. We show that the dispersion of an assembly of puller type microswimmers is quantitatively affected by hydrodynamics interactions. Phd student.

  8. Simple Waves in Ideal Radiation Hydrodynamics

    SciTech Connect

    Johnson, B M

    2008-09-03

    In the dynamic diffusion limit of radiation hydrodynamics, advection dominates diffusion; the latter primarily affects small scales and has negligible impact on the large scale flow. The radiation can thus be accurately regarded as an ideal fluid, i.e., radiative diffusion can be neglected along with other forms of dissipation. This viewpoint is applied here to an analysis of simple waves in an ideal radiating fluid. It is shown that much of the hydrodynamic analysis carries over by simply replacing the material sound speed, pressure and index with the values appropriate for a radiating fluid. A complete analysis is performed for a centered rarefaction wave, and expressions are provided for the Riemann invariants and characteristic curves of the one-dimensional system of equations. The analytical solution is checked for consistency against a finite difference numerical integration, and the validity of neglecting the diffusion operator is demonstrated. An interesting physical result is that for a material component with a large number of internal degrees of freedom and an internal energy greater than that of the radiation, the sound speed increases as the fluid is rarefied. These solutions are an excellent test for radiation hydrodynamic codes operating in the dynamic diffusion regime. The general approach may be useful in the development of Godunov numerical schemes for radiation hydrodynamics.

  9. Hydrodynamically driven colloidal assembly in dip coating.

    PubMed

    Colosqui, Carlos E; Morris, Jeffrey F; Stone, Howard A

    2013-05-01

    We study the hydrodynamics of dip coating from a suspension and report a mechanism for colloidal assembly and pattern formation on smooth substrates. Below a critical withdrawal speed where the coating film is thinner than the particle diameter, capillary forces induced by deformation of the free surface prevent the convective transport of single particles through the meniscus beneath the film. Capillary-induced forces are balanced by hydrodynamic drag only after a minimum number of particles assemble within the meniscus. The particle assembly can thus enter the thin film where it moves at nearly the withdrawal speed and rapidly separates from the next assembly. The interplay between hydrodynamic and capillary forces produces periodic and regular structures below a critical ratio Ca(2/3)/sqrt[Bo] < 0.7, where Ca and Bo are the capillary and Bond numbers, respectively. An analytical model and numerical simulations are presented for the case of two-dimensional flow with circular particles in suspension. The hydrodynamically driven assembly documented here is consistent with stripe pattern formations observed experimentally in dip coating.

  10. Livermore Unstructured Lagrange Explicit Shock Hydrodynamics

    2010-09-21

    LULESH v1.0 is a 3D unstructured Lagrange hydrodynamics simulation written specifically to solve a standard analytical test problem, known as the Sedov problem. In this problem, a quantum of energy is deposited into a gas and propagates through the gas over time.

  11. Boundary conditions in tunneling via quantum hydrodynamics

    NASA Technical Reports Server (NTRS)

    Nassar, Antonio B.

    1993-01-01

    Via the hydrodynamical formulation of quantum mechanics, an approach to the problem of tunneling through sharp-edged potential barriers is developed. Above all, it is shown how more general boundary conditions follow from the continuity of mass, momentum, and energy.

  12. Hydrodynamically Driven Colloidal Assembly in Dip Coating

    NASA Astrophysics Data System (ADS)

    Colosqui, Carlos E.; Morris, Jeffrey F.; Stone, Howard A.

    2013-05-01

    We study the hydrodynamics of dip coating from a suspension and report a mechanism for colloidal assembly and pattern formation on smooth substrates. Below a critical withdrawal speed where the coating film is thinner than the particle diameter, capillary forces induced by deformation of the free surface prevent the convective transport of single particles through the meniscus beneath the film. Capillary-induced forces are balanced by hydrodynamic drag only after a minimum number of particles assemble within the meniscus. The particle assembly can thus enter the thin film where it moves at nearly the withdrawal speed and rapidly separates from the next assembly. The interplay between hydrodynamic and capillary forces produces periodic and regular structures below a critical ratio Ca2/3/Bo<0.7, where Ca and Bo are the capillary and Bond numbers, respectively. An analytical model and numerical simulations are presented for the case of two-dimensional flow with circular particles in suspension. The hydrodynamically driven assembly documented here is consistent with stripe pattern formations observed experimentally in dip coating.

  13. Hydrodynamic Issues in PAMS Mandrel Target Fabrication

    SciTech Connect

    McQuillan, B M; Paguio, R; Subramanian, P; Takagi, M; Zebib, A

    2003-08-27

    Imperfections in PAMS mandrels critically govern the quality of final ICF targets. Imperfections in the mandrels can have a wide range of origins. Here, they present observations of 3 types of imperfections, and data to support the proposal that hydrodynamic factors during the curing of the mandrel are potential causes of these imperfections.

  14. HYDRODYNAMIC ISSUES IN PAMS MANDREL TARGET FABRICATION

    SciTech Connect

    McQUILLAN,B.W; PAGUIO,R; SUBRAMANIAN,P; TAKAGI,M; ZEBIB,A

    2003-09-01

    OAK-B135 Imperfections in PAMS mandrels critically govern the quality of final ICF targets. Imperfections in the mandrels can have a wide range of origins. Here, they present observations of 3 types of imperfections, and data to support the proposal that hydrodynamic factors during the curing of the mandrel are potential causes of these imperfections.

  15. Chiral Magnetic Effect in Hydrodynamic Approximation

    NASA Astrophysics Data System (ADS)

    Zakharov, Valentin I.

    We review derivations of the chiral magnetic effect (ChME) in hydrodynamic approximation. The reader is assumed to be familiar with the basics of the effect. The main challenge now is to account for the strong interactions between the constituents of the fluid. The main result is that the ChME is not renormalized: in the hydrodynamic approximation it remains the same as for non-interacting chiral fermions moving in an external magnetic field. The key ingredients in the proof are general laws of thermodynamics and the Adler-Bardeen theorem for the chiral anomaly in external electromagnetic fields. The chiral magnetic effect in hydrodynamics represents a macroscopic manifestation of a quantum phenomenon (chiral anomaly). Moreover, one can argue that the current induced by the magnetic field is dissipation free and talk about a kind of "chiral superconductivity". More precise description is a quantum ballistic transport along magnetic field taking place in equilibrium and in absence of a driving force. The basic limitation is the exact chiral limit while temperature—excitingly enough—does not seemingly matter. What is still lacking, is a detailed quantum microscopic picture for the ChME in hydrodynamics. Probably, the chiral currents propagate through lower-dimensional defects, like vortices in superfluid. In case of superfluid, the prediction for the chiral magnetic effect remains unmodified although the emerging dynamical picture differs from the standard one.

  16. Evaluation of dental panoramic radiographic findings in edentulous jaws: A retrospective study of 743 patients "Radiographic features in edentulous jaws"

    PubMed Central

    Kose, Taha Emre; Cakir Karabas, Hulya; Ozcan, Ilknur

    2015-01-01

    PURPOSE The aim of this study was to determine the frequency of significant panoramic radiographic findings and eventual treatment requirements before conventional or implant supported prosthetic treatment in asymptomatic edentulous patients. MATERIALS AND METHODS A total of 743 asymptomatic edentulous patients were retrospectively evaluated using a digital panoramic system. We analyzed the radiographic findings, including impacted teeth, retained root fragments, foreign bodies, severe atrophy of the posterior maxillary alveolar bone, mucous retention cysts, soft tissue calcifications and radiopaque-radiolucent conditions. RESULTS Four-hundred-eighty-seven (65.6%) patients had no radiographic finding. A total of 331 radiographic findings were detected in 256 (34%) patients. In 52.9% (n=175) of these conditions, surgical treatment was required before application of implant-supported fixed prosthesis. However, before application of conventional removable prosthesis surgical treatment was required for 6% (n=20) of these conditions. CONCLUSION The edentulous patients who will have implant placement for implant-supported fixed prosthesis can frequently require additional surgical procedures to eliminate pathological conditions. PMID:26576254

  17. Investigating the global collapse of filaments using smoothed particle hydrodynamics

    NASA Astrophysics Data System (ADS)

    Clarke, S. D.; Whitworth, A. P.

    2015-05-01

    We use smoothed particle hydrodynamic simulations of cold, uniform density, self-gravitating filaments, to investigate their longitudinal collapse time-scales; these time-scales are important because they determine the time available for a filament to fragment into cores. A filament is initially characterized by its line-mass, μO, its radius, RO (or equivalently its density ρ O= μ O/π RO^2), and its aspect ratio, AO (≡ZO/RO, where ZO is its half-length). The gas is only allowed to contract longitudinally, i.e. parallel to the symmetry axis of the filament (the z-axis). Pon et al. (2012) have considered the global dynamics of such filaments analytically. They conclude that short filaments (AO ≲ 5) collapse along the z-axis more-or-less homologously, on a time-scale tHOM ˜ 0.44 AO (GρO)-1/2; in contrast, longer filaments (AO ≳ 5) undergo end-dominated collapse, i.e. two dense clumps form at the ends of the filament and converge on the centre sweeping up mass as they go, on a time-scale t_{END} ˜ 0.98 AO^{1/2} (Gρ O)^{-1/2}. Our simulations do not corroborate these predictions. First, for all AO ≳ 2, the collapse time satisfies a single equation t_{COL}˜ (0.49+0.26AO)(Gρ O)^{-1/2}, which for large AO is much longer than the Pon et al. prediction. Secondly, for all AO ≳ 2, the collapse is end-dominated. Thirdly, before being swept up, the gas immediately ahead of an end-clump is actually accelerated outwards by the gravitational attraction of the approaching clump, resulting in a significant ram pressure. For high aspect ratio filaments, the end-clumps approach an asymptotic inward speed, due to the fact that they are doing work both accelerating and compressing the gas they sweep up. Pon et al. appear to have neglected the outward acceleration and its consequences.

  18. Testing different formulations of leading-order anisotropic hydrodynamics

    NASA Astrophysics Data System (ADS)

    Tinti, Leonardo; Ryblewski, Radoslaw; Florkowski, Wojciech; Strickland, Michael

    2016-02-01

    A recently obtained set of the equations for leading-order (3+1)D anisotropic hydrodynamics is tested against exact solutions of the Boltzmann equation with the collisional kernel treated in the relaxation time approximation. In order to perform detailed comparisons, the new anisotropic hydrodynamics equations are reduced to the boost-invariant and transversally homogeneous case. The agreement with the exact solutions found using the new anisotropic hydrodynamics equations is similar to that found using previous, less general formulations of anisotropic hydrodynamics. In addition, we find that, when compared to a state-of-the-art second-order viscous hydrodynamics framework, leading-order anisotropic hydrodynamics better reproduces the exact solution for the pressure anisotropy and gives comparable results for the bulk pressure evolution. Finally, we compare the transport coefficients obtained using linearized anisotropic hydrodynamics with results obtained using second-order viscous hydrodynamics.

  19. Scaling supernova hydrodynamics to the laboratory

    SciTech Connect

    Kane, J.O.

    1999-06-01

    Supernova (SN) 1987A focused attention on the critical role of hydrodynamic instabilities in the evolution of supernovae. To test the modeling of these instabilities, we are developing laboratory experiments of hydrodynamic mixing under conditions relevant to supernovae. Initial results were reported in J. Kane et al., Astrophys. J.478, L75 (1997) The Nova laser is used to shock two-layer targets, producing Richtmyer-Meshkov (RM) and Rayleigh-Taylor (RT) instabilities at the interfaces between the layers, analogous to instabilities seen at the interfaces of SN 1987A. Because the hydrodynamics in the laser experiments at intermediate times (3-40 ns) and in SN 1987A at intermediate times (5 s-10{sup 4} s) are well described by the Euler equations, the hydrodynamics scale between the two regimes. The experiments are modeled using the hydrodynamics codes HYADES and CALE, and the supernova code PROMETHEUS, thus serving as a benchmark for PROMETHEUS. Results of the experiments and simulations are presented. Analysis of the spike and bubble velocities in the experiment using potential flow theory and a modified Ott thin shell theory is presented. A numerical study of 2D vs. 3D differences in instability growth at the O-He and He-H interface of SN 1987A, and the design for analogous laser experiments are presented. We discuss further work to incorporate more features of the SN in the experiments, including spherical geometry, multiple layers and density gradients. Past and ongoing work in laboratory and laser astrophysics is reviewed, including experimental work on supernova remnants (SNRs). A numerical study of RM instability in SNRs is presented.

  20. Scaling supernova hydrodynamics to the laboratory

    SciTech Connect

    Kane, J.; Arnett, D.; Remington, B.A.; Glendinning, S.G.; Bazan, G.; Drake, R.P.; Fryxell, B.A.; Teyssier, R.

    1999-05-01

    Supernova (SN) 1987A focused attention on the critical role of hydrodynamic instabilities in the evolution of supernovae. To test the modeling of these instabilities, we are developing laboratory experiments of hydrodynamic mixing under conditions relevant to supernovae. Initial results were reported in J. Kane {ital et al.} [Astrophys. J. {bold 478}, L75 (1997) and B. A. Remington {ital et al.}, Phys. Plasmas {bold 4}, 1994 (1997)]. The Nova laser is used to generate a 10{endash}15 Mbar shock at the interface of a two-layer planar target, which triggers perturbation growth due to the Richtmyer{endash}Meshkov instability, and to the Rayleigh{endash}Taylor instability as the interface decelerates. This resembles the hydrodynamics of the He-H interface of a Type II supernova at intermediate times, up to a few {times}10{sup 3}s. The scaling of hydrodynamics on microscopic laser scales to the SN-size scales is presented. The experiment is modeled using the hydrodynamics codes HYADES [J. T. Larson and S. M. Lane, J. Quant. Spect. Rad. Trans. {bold 51}, 179 (1994)] and CALE [R. T. Barton, {ital Numerical Astrophysics} (Jones and Bartlett, Boston, 1985), pp. 482{endash}497], and the supernova code PROMETHEUS [P. R. Woodward and P. Collela, J. Comp. Phys. {bold 54}, 115 (1984)]. Results of the experiments and simulations are presented. Analysis of the spike-and-bubble velocities using potential flow theory and Ott thin-shell theory is presented, as well as a study of 2D versus 3D differences in perturbation growth at the He-H interface of SN 1987A.

  1. Off-axis reflective optical apparatus

    NASA Technical Reports Server (NTRS)

    Ames, Lawrence L. (Inventor); Leary, David F. (Inventor); Mammini, Paul V. (Inventor)

    2005-01-01

    Embodiments of the present invention are directed to a simple apparatus and a convenient and accurate method of mounting the components to form an off-axis reflective optical apparatus such as a collimator. In one embodiment, an off-axis reflective optical apparatus comprises a mounting block having a ferrule holder support surface and an off-axis reflector support surface which is generally perpendicular to the ferrule holder support surface. An optical reflector is mounted on the off-axis reflector support surface and has a reflected beam centerline. The optical reflector has a conic reflective surface and a conic center. A ferrule holder is mounted on the ferrule holder support surface. The ferrule holder provides a ferrule for coupling to an optical fiber and orienting a fiber tip of the optical fiber along a fiber axis toward the optical reflector. The fiber axis is nonparallel to the reflected beam centerline. Prior to mounting the optical reflector to the off-axis reflector support surface and prior to mounting the ferrule holder to the ferrule holder support surface, the optical reflector is movable on the off-axis reflector surface and the ferrule holder is movable on the ferrule holder support surface to align the conic center of the optical reflector with respect to the fiber tip of the optical fiber, and the apparatus has at least one of the following features: (1) the optical reflector is movable on the off-axis reflector support surface to adjust a focus of the fiber tip with respect to the optical reflector, and (2) the ferrule holder is movable on the ferrule holder support surface to adjust the focus of the fiber tip with respect to the optical reflector.

  2. Correlation between broiler lameness and anatomical measurements of bone using radiographical projections with assessments of consistency across and within radiographs.

    PubMed

    Toscano, M J; Nasr, M A F; Hothersall, B

    2013-09-01

    Lameness represents a major welfare and production issue in the poultry industry with a recent survey estimating 27% of birds lame and 3% unable to walk by 40 d of age. A variety of factors may induce lameness and are typically grouped into 2 broad classes on the basis of being infectious or skeletal in nature with the latter accounting for the majority of cases. The current work sought to build upon a large body of literature assessing the anatomical properties of bone in lame birds. Our specific objectives sought to identify relationships between relevant anatomical properties of the tibia and metatarsus using digital quantification from radiographs of legs and a measure of walking difficulty. Resulting output was statistically analyzed to assess 1) observer reliability for consistency in placing the leg during the radiograph procedure and quantification of the various measures within a radiograph, 2) the relationship between the various measurements of anatomical bone properties and sex, bird mass, and gait score, and 3) the relationship between each measurement and leg symmetry. Our anatomical bone measures were found to be reliable (intra-rater and test-retest reliabilities < 0.75) within radiograph for all measures and 8 of the 10 measures across radiographs. Several measures of bone properties in the tibia correlated to difficulty walking as measured by gait score (P < 0.05), indicating greater angulations with increasing lameness. Of the measures that manifested a gait score × bird mass interaction, heavier birds appeared to exhibit less angulation with increasing difficulty walking with lighter birds the opposite. These interactions suggest possibilities for influencing effects of activity or feed intake on bone mineralization with the bone angulation observed. Our efforts agree with that of others and indicate that angulation of the tibia may be related to lameness, though subsequent efforts involving comprehensive measures of bird activity, growth rates

  3. 21 CFR 892.1880 - Wall-mounted radiographic cassette holder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Wall-mounted radiographic cassette holder. 892.1880 Section 892.1880 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... radiographic cassette holder. (a) Identification. A wall-mounted radiographic cassette holder is a device...

  4. 21 CFR 892.1870 - Radiographic film/cassette changer programmer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic film/cassette changer programmer. 892... SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1870 Radiographic film/cassette changer programmer. (a) Identification. A radiographic film/cassette changer programmer is...

  5. 21 CFR 892.1870 - Radiographic film/cassette changer programmer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Radiographic film/cassette changer programmer. 892... SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1870 Radiographic film/cassette changer programmer. (a) Identification. A radiographic film/cassette changer programmer is...

  6. The effect of spine postures on the hydrodynamic drag in Epinephelus ongus larvae.

    PubMed

    Kawabata, Y; Nishihara, G N; Yamaguchi, T; Takebe, T; Teruya, K; Sato, T; Soyano, K

    2014-11-01

    Laboratory behavioural observation and computational fluid dynamics (CFD) analysis were conducted to examine whether the movement of the elongated dorsal and pelvic spines changed the hydrodynamic drag in white-streaked grouper Epinephelus ongus larvae. The behavioural observation in the tank revealed that the larvae extended the dorsal and pelvic spines during passive transport and retracted during swimming; the angles of the dorsal and pelvic spines in relation to the anteroposterior axis were larger during the passive transport (mean ± S.D. = 28.84 ± 14.27 and 20.35 ± 15.05°) than those during the swimming (mean ± S.D. = 2.59 ± 5.55 and 0.32 ± 6.49°). The CFD analysis indicated that the relative hydrodynamic drag acting on the larvae was approximately 1.25 times higher when the spines were extended (passive transport) than when the spines were retracted (swimming), suggesting that the E. ongus larvae have an ability to adjust their hydrodynamic drag depending on the behavioural context.

  7. 78 FR 9907 - Hydrodynamics, Inc.; Notice Denying Late Intervention

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-12

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Hydrodynamics, Inc.; Notice Denying Late Intervention On June 24, 2010, Commission staff issued a three-year preliminary permit to Hydrodynamics, Inc. (Hydrodynamics) to study...

  8. Radiographic knee osteoarthritis in ex-elite table tennis players

    PubMed Central

    2012-01-01

    Background Table tennis involves adoption of the semi-flexed knee and asymmetrical torsional trunk movements creating rotational torques on the knee joint which may predispose players to osteoarthritis (OA) of the knee. This study aims to compare radiographic signs of knee OA and associated functional levels in ex-elite male table tennis players and control subjects. Methods Study participants were 22 ex-elite male table tennis players (mean age 56.64 ± 5.17 years) with 10 years of involvement at the professional level and 22 non-athletic males (mean age 55.63 ± 4.08 years) recruited from the general population. A set of three radiographs taken from each knee were evaluated by an experienced radiologist using the Kellgren and Lawrence (KL) scale (0-4) to determine radiographic levels of OA severity. The intercondylar distance was taken as a measure of lower limb angulation. Participants also completed the pain, stiffness, and physical function categories of the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) 3.1 questionnaire. Results The results showed 78.3% of the ex-elite table tennis players and 36.3% of controls had varying signs of radiographic knee OA with a significant difference in the prevalence levels of definite radiographic OA (KL scale > 2) found between the two groups (P ≤ 0.001). Based on the WOMAC scores, 68.2% of the ex-elite table tennis players reported symptoms of knee pain compared with 27.3% of the controls (p = 0.02) though no significant differences were identified in the mean physical function or stiffness scores between the two groups. In terms of knee alignment, 73.7% of the ex-elite athletes and 32% of the control group had signs of altered lower limb alignment (genu varum) (p = 0.01). Statistical differences were found in subjects categorized as having radiographic signs of OA and altered lower limb alignment (p = 0.03). Conclusions Ex-elite table tennis players were found to have increased levels of

  9. CFD simulation of fixed and variable pitch vertical axis tidal turbine

    NASA Astrophysics Data System (ADS)

    Sheng, Qihu; Khalid, Syed Shah; Xiong, Zhimin; Sahib, Ghazala; Zhang, Liang

    2013-06-01

    In this paper, hydrodynamic analysis of vertical axis tidal turbine (both fixed pitch & variable pitch) is numerically analyzed. Two-dimensional numerical modeling & simulation of the unsteady flow through the blades of the turbine is performed using ANSYS CFX, hereafter CFX, which is based on a Reynolds-Averaged Navier-Stokes (RANS) model. A transient simulation is done for fixed pitch and variable pitch vertical axis tidal turbine using a Shear Stress Transport turbulence (SST) scheme. Main hydrodynamic parameters like torque T, combined moment C M , coefficients of performance C P and coefficient of torque C T , etc. are investigated. The modeling and meshing of turbine rotor is performed in ICEM-CFD. Moreover, the difference in meshing schemes between fixed pitch and variable pitch is also mentioned. Mesh motion option is employed for variable pitch turbine. This article is one part of the ongoing research on turbine design and developments. The numerical simulation results are validated with well reputed analytical results performed by Edinburgh Design Ltd. The article concludes with a parametric study of turbine performance, comparison between fixed and variable pitch operation for a four-bladed turbine. It is found that for variable pitch we get maximum C P and peak power at smaller revolution per minute N and tip sped ratio λ.

  10. Vertical Axis Wind Turbine Foundation parameter study

    SciTech Connect

    Lodde, P.F.

    1980-07-01

    The dynamic failure criterion governing the dimensions of prototype Vertical Axis Wind Turbine Foundations is treated as a variable parameter. The resulting change in foundation dimensions and costs is examined.

  11. Model-based vision system for automatic recognition of structures in dental radiographs

    NASA Astrophysics Data System (ADS)

    Acharya, Raj S.; Samarabandu, Jagath K.; Hausmann, E.; Allen, K. A.

    1991-07-01

    X-ray diagnosis of destructive periodontal disease requires assessing serial radiographs by an expert to determine the change in the distance between cemento-enamel junction (CEJ) and the bone crest. To achieve this without the subjectivity of a human expert, a knowledge based system is proposed to automatically locate the two landmarks which are the CEJ and the level of alveolar crest at its junction with the periodontal ligament space. This work is a part of an ongoing project to automatically measure the distance between CEJ and the bone crest along a line parallel to the axis of the tooth. The approach presented in this paper is based on identifying a prominent feature such as the tooth boundary using local edge detection and edge thresholding to establish a reference and then using model knowledge to process sub-regions in locating the landmarks. Segmentation techniques invoked around these regions consists of a neural-network like hierarchical refinement scheme together with local gradient extraction, multilevel thresholding and ridge tracking. Recognition accuracy is further improved by first locating the easily identifiable parts of the bone surface and the interface between the enamel and the dentine and then extending these boundaries towards the periodontal ligament space and the tooth boundary respectively. The system is realized as a collection of tools (or knowledge sources) for pre-processing, segmentation, primary and secondary feature detection and a control structure based on the blackboard model to coordinate the activities of these tools.

  12. Electrical-Discharge Machining With Additional Axis

    NASA Technical Reports Server (NTRS)

    Malinzak, Roger M.; Booth, Gary N.

    1991-01-01

    Proposed electrical-discharge-machining (EDM) apparatus uses moveable vertical wire as electrode. Wire positionable horizontally along one axis as it slides vertically past workpiece. Workpiece indexed in rotation about horizontal axis. Because of symmetry of parts, process used to make two such parts at a time by defining boundary between them. Advantages: cost of material reduced, imparts less residual stress to workpiece, and less time spent machining each part when parts produced in such symmetrical pairs.

  13. 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.

  14. Computer assisted measurement of femoral cortex thickening on radiographs

    NASA Astrophysics Data System (ADS)

    Yao, Jianhua; Liu, Yixun; Chen, Foster; Summers, Ronald M.; Bhattacharyya, Timothy

    2013-03-01

    Radiographic features such as femoral cortex thickening have been frequently observed with atypical subtrochanteric fractures. These features may be a valuable finding to help prevent fractures before they happen. The current practice of manual measurement is often subjective and inconsistent. We developed a semi-automatic tool to consistently measure and monitor the progress of femoral cortex thickening on radiographs. By placing two seed points on each side of the femur, the program automatically extracts the periosteal and endosteal layers of the cortical shell by active contour models and B-spline fitting. Several measurements are taken along the femur shaft, including shaft diameter, cortical thickness, and integral area for medial and lateral cortex. The experiment was conducted on 52 patient datasets. The semi-automatic measurements were validated against manual measurements on 52 patients and demonstrated great improvement in consistency and accuracy (p<0.001).

  15. Incidental radiographic finding of the concealed art of susuk.

    PubMed

    Devang Divakar, Darshan; Mavinapalla, Seema; Al Kheraif, Abdulaziz Abdullah; Ramakrishnaiah, Ravikumar; Abd Rahim, Muhammad Furqon Bin; Khan, Aftab Ahmed

    2016-07-01

    Susuk, or charm needles, are small, metallic needles inserted under the skin, considered to enhance beauty, health and luck. This hidden secret of inserting susuk is a traditional superstitious ritual, widely practiced among women of Southeast Asia. Here, we present an interesting case of incidental radiographic finding of the concealed art of susuk, which was exposed on a panoramic radiograph taken on a routine basis as a part of diagnostic work up at our centre. An orthopantomogram revealed bilateral metallic foreign bodies in the maxillo-facial region. Anamnestic data affirmed the practice of the body art of susuk. The charm needles were present in the orofacial region without the patient experiencing any pathological signs or symptoms.

  16. Texture analysis of hand radiographs to assess bone structure

    NASA Astrophysics Data System (ADS)

    Klifa, Catherine S.; Lin, John C.; Augat, Peter; Fuerst, Thomas; Jiang, Yebin; Majumdar, Sharmila; Genant, Harry K.

    1998-06-01

    In this study we compared trabecular bone mineral density (BMD) with textural parameters (cooccurence matrices features) extracted from trabecular bone structures in radiographic images of the hand. Our data consists of 12 cadaver hands radiographed and digitized. After application of a specific preprocessing step on all images, the textural parameters were calculated within 4 regions of interest defined within the metacarpal and proximal phalanges on trabecular bone. The results show that using a combination of textural parameters calculated at different directions within the ROI could increase significantly the correlation with BMD. Some further research will validate this finding on a larger set of data. This work is intended to be applicable in the study of bone fractures associated with osteoporosis, and could be of great benefit to a large segment of the population at risk.

  17. A Bayesian Measurment Error Model for Misaligned Radiographic Data

    SciTech Connect

    Lennox, Kristin P.; Glascoe, Lee G.

    2013-09-06

    An understanding of the inherent variability in micro-computed tomography (micro-CT) data is essential to tasks such as statistical process control and the validation of radiographic simulation tools. The data present unique challenges to variability analysis due to the relatively low resolution of radiographs, and also due to minor variations from run to run which can result in misalignment or magnification changes between repeated measurements of a sample. Positioning changes artificially inflate the variability of the data in ways that mask true physical phenomena. We present a novel Bayesian nonparametric regression model that incorporates both additive and multiplicative measurement error in addition to heteroscedasticity to address this problem. We also use this model to assess the effects of sample thickness and sample position on measurement variability for an aluminum specimen. Supplementary materials for this article are available online.

  18. A Bayesian Measurment Error Model for Misaligned Radiographic Data

    DOE PAGES

    Lennox, Kristin P.; Glascoe, Lee G.

    2013-09-06

    An understanding of the inherent variability in micro-computed tomography (micro-CT) data is essential to tasks such as statistical process control and the validation of radiographic simulation tools. The data present unique challenges to variability analysis due to the relatively low resolution of radiographs, and also due to minor variations from run to run which can result in misalignment or magnification changes between repeated measurements of a sample. Positioning changes artificially inflate the variability of the data in ways that mask true physical phenomena. We present a novel Bayesian nonparametric regression model that incorporates both additive and multiplicative measurement error inmore » addition to heteroscedasticity to address this problem. We also use this model to assess the effects of sample thickness and sample position on measurement variability for an aluminum specimen. Supplementary materials for this article are available online.« less

  19. Sand aspiration with near-drowning. Radiographic and bronchoscopic findings.

    PubMed

    Dunagan, D P; Cox, J E; Chang, M C; Haponik, E F

    1997-07-01

    Sand and foreign-body aspiration may accompany drowning and near-drowning, but few details regarding such patients are available in the literature. We report a 26-yr-old woman who suffered near-drowning after a motor-vehicle accident. Initial attempts at ventilation were compromised by increased peak airway pressures, which decreased following the removal of large amounts of sand from the patient's endotracheal tube. Chest radiographs and computed tomographic (CT) scans of the patient obtained upon her arrival in the emergency department demonstrated sand bronchograms within the lower lobes of both lungs, and sand within the maxillary sinuses and stomach. We present the radiographic, bronchoscopic, and microbiologic findings within hours after this patient's accident, with a review of the literature and provisional recommendations for the management of such patients.

  20. A Computer-Aided Detection System for Digital Chest Radiographs.

    PubMed

    Carrillo-de-Gea, Juan Manuel; García-Mateos, Ginés; Fernández-Alemán, José Luis; Hernández-Hernández, José Luis

    2016-01-01

    Computer-aided detection systems aim at the automatic detection of diseases using different medical imaging modalities. In this paper, a novel approach to detecting normality/pathology in digital chest radiographs is proposed. The problem tackled is complicated since it is not focused on particular diseases but anything that differs from what is considered as normality. First, the areas of interest of the chest are found using template matching on the images. Then, a texture descriptor called local binary patterns (LBP) is computed for those areas. After that, LBP histograms are applied in a classifier algorithm, which produces the final normality/pathology decision. Our experimental results show the feasibility of the proposal, with success rates above 87% in the best cases. Moreover, our technique is able to locate the possible areas of pathology in nonnormal radiographs. Strengths and limitations of the proposed approach are described in the Conclusions. PMID:27372536

  1. The ORTEGA experiment: Radiographic methods, analysis and results

    NASA Astrophysics Data System (ADS)

    Haines, Todd; King, Nick; Lutz, Steve; Smith, John

    2011-06-01

    The ORTEGA experiment, executed on July 28th , 2010 by a team from Los Alamos, Sandia, National Security Technologies, and others, at the Nevada National Security Site, consisted of two identical samples of lead driven by small charges of HE. Flash x-radiography formed the key measurement. A short pulse of x-rays ``froze'' the motion much like a flash camera system and thereby permitted examination of the instantaneous internal spatial density distribution of the rapidly moving material. Two radiographs were taken encompassing both samples in each image and separated in time by ~4 microseconds to allow observation of the evolution of the samples. This presentation will review the radiographic methodology, the data set, calibration and details of the analysis of the data.

  2. Incidental radiographic finding of the concealed art of susuk.

    PubMed

    Devang Divakar, Darshan; Mavinapalla, Seema; Al Kheraif, Abdulaziz Abdullah; Ramakrishnaiah, Ravikumar; Abd Rahim, Muhammad Furqon Bin; Khan, Aftab Ahmed

    2016-07-01

    Susuk, or charm needles, are small, metallic needles inserted under the skin, considered to enhance beauty, health and luck. This hidden secret of inserting susuk is a traditional superstitious ritual, widely practiced among women of Southeast Asia. Here, we present an interesting case of incidental radiographic finding of the concealed art of susuk, which was exposed on a panoramic radiograph taken on a routine basis as a part of diagnostic work up at our centre. An orthopantomogram revealed bilateral metallic foreign bodies in the maxillo-facial region. Anamnestic data affirmed the practice of the body art of susuk. The charm needles were present in the orofacial region without the patient experiencing any pathological signs or symptoms. PMID:26271077

  3. Massive reflux and aspiration after radiographically inserted gastrostomy tube placement.

    PubMed

    Chesoni, Sandra A; Bach, John R; Okamura, Erica Mia

    2015-01-01

    To the authors' knowledge, fatal postgastrostomy aspiration within 2 days of enteral nutrition has not been reported. The authors report consecutive cases of severe postgastrotomy aspiration with one being fatal for a 26-yr-old with Duchenne muscular dystrophy 2 days after initiation of gastrostomy feedings. Previous to these consecutive radiographically inserted gastrostomies, all gastrotomies at the institution were percutaneous endoscopic gastrostomies or open gastrostomies. Radiographically inserted gastrostomy tubes have an increased likelihood of being oriented toward the esophagus as opposed to the duodenum, which may increase the risk for reflux. Elimination of invasive airway tubes should be delayed until after gastrostomy feedings are documented to be well tolerated. Oximetry and repeated measurements of vital capacity can suggest changes in the status of airway clearance.

  4. Radiograph and passive data analysis using mixed variable optimization

    DOEpatents

    Temple, Brian A.; Armstrong, Jerawan C.; Buescher, Kevin L.; Favorite, Jeffrey A.

    2015-06-02

    Disclosed herein are representative embodiments of methods, apparatus, and systems for performing radiography analysis. For example, certain embodiments perform radiographic analysis using mixed variable computation techniques. One exemplary system comprises a radiation source, a two-dimensional detector for detecting radiation transmitted through a object between the radiation source and detector, and a computer. In this embodiment, the computer is configured to input the radiographic image data from the two-dimensional detector and to determine one or more materials that form the object by using an iterative analysis technique that selects the one or more materials from hierarchically arranged solution spaces of discrete material possibilities and selects the layer interfaces from the optimization of the continuous interface data.

  5. Radiographic findings in the chest of patients following cardiac transplantation

    SciTech Connect

    Shirazi, K.K.; Amendola, M.A.; Tisnado, J.; Cho, S.R.; Beachley, M.C.; Lower, R.R.

    1983-04-01

    The postoperative chest radiographic findings in 38 patients undergoing orthotopic (37 patients) and heterotopic (1 patient) cardiac transplantation were evaluated. Findings were correlated with those of echocardiograms, sputum and blood cultures, and lung and heart biopsies. The radiographic manifestations in the chest of these patients are classified in the following three main categories: 1) newly formed cardiac silhouette findings due to the transplanted heart itself, i.e., changes in size and shape of the new heart and pericardial effusion resulting from the placement of a smaller heart in a larger pericardial sac. 2) infectious complications due to bacteria, fungal, and other opportunistic agents secondary to immunosuppressive therapy, and 3) usual postoperative complications following thoracomoty and open-heart surgery.

  6. Sex differences in the HPA axis.

    PubMed

    Goel, Nirupa; Workman, Joanna L; Lee, Tiffany T; Innala, Leyla; Viau, Victor

    2014-07-01

    The hypothalamic-pituitary-adrenal (HPA) axis is a major component of the systems that respond to stress, by coordinating the neuroendocrine and autonomic responses. Tightly controlled regulation of HPA responses is critical for maintaining mental and physical health, as hyper- and hypo-activity have been linked to disease states. A long history of research has revealed sex differences in numerous components of the HPA stress system and its responses, which may partially form the basis for sex disparities in disease development. Despite this, many studies use male subjects exclusively, while fewer reports involve females or provide direct sex comparisons. The purpose of this article is to present sex comparisons in the functional and molecular aspects of the HPA axis, through various phases of activity, including basal, acute stress, and chronic stress conditions. The HPA axis in females initiates more rapidly and produces a greater output of stress hormones. This review focuses on the interactions between the gonadal hormone system and the HPA axis as the key mediators of these sex differences, whereby androgens increase and estrogens decrease HPA activity in adulthood. In addition to the effects of gonadal hormones on the adult response, morphological impacts of hormone exposure during development are also involved in mediating sex differences. Additional systems impinging on the HPA axis that contribute to sex differences include the monoamine neurotransmitters norepinephrine and serotonin. Diverse signals originating from the brain and periphery are integrated to determine the level of HPA axis activity, and these signals are, in many cases, sex-specific.

  7. Descriptive Quantitative Analysis of Rearfoot Alignment Radiographic Parameters.

    PubMed

    Meyr, Andrew J; Wagoner, Matthew R

    2015-01-01

    Although the radiographic parameters of the transverse talocalcaneal angle (tTCA), calcaneocuboid angle (CCA), talar head uncovering (THU), calcaneal inclination angle (CIA), talar declination angle (TDA), lateral talar-first metatarsal angle (lTFA), and lateral talocalcaneal angle (lTCA) form the basis of the preoperative evaluation and procedure selection for pes planovalgus deformity, the so-called normal values of these measurements are not well-established. The objectives of the present study were to retrospectively evaluate the descriptive statistics of these radiographic parameters (tTCA, CCA, THU, CIA, TDA, lTFA, and lTCA) in a large population, and, second, to determine an objective basis for defining "normal" versus "abnormal" measurements. As a secondary outcome, the relationship of these variables to the body mass index was assessed. Anteroposterior and lateral foot radiographs from 250 consecutive patients without a history of previous foot and ankle surgery and/or trauma were evaluated. The results revealed a mean measurement of 24.12°, 13.20°, 74.32%, 16.41°, 26.64°, 8.37°, and 43.41° for the tTCA, CCA, THU, CIA, TDA, lTFA, and lTCA, respectively. These were generally in line with the reported historical normal values. Descriptive statistical analysis demonstrated that the tTCA, THU, and TDA met the standards to be considered normally distributed but that the CCA, CIA, lTFA, and lTCA demonstrated data characteristics of both parametric and nonparametric distributions. Furthermore, only the CIA (R = -0.2428) and lTCA (R = -0.2449) demonstrated substantial correlation with the body mass index. No differentiations in deformity progression were observed when the radiographic parameters were plotted against each other to lead to a quantitative basis for defining "normal" versus "abnormal" measurements. PMID:26002682

  8. Thoracic radiographic features of silicosis in 19 horses.

    PubMed

    Berry, C R; O'Brien, T R; Madigan, J E; Hager, D A

    1991-01-01

    Clinical records and thoracic radiographs of 19 horses with a confirmed pathologic diagnosis of silicosis were reviewed. These horses had histories of varying degrees of chronic weight loss, exercise intolerance, and respiratory distress. At the time of presentation, two horses were asymptomatic. Ten horses were geldings and nine were female. The mean age of the 19 horses was 10.7 +/- 5.5 years. Fourteen horses were identified as being from the Monterey-Carmel Peninsula of midcoastal California. An abnormal, structured interstitial pulmonary pattern was identified on thoracic radiographs in each horse. The interstitial pulmonary changes were classified as miliary (13 horses), reticulonodular (4), or linear interstitial (2), and were best visualized dorsally and caudodorsally. In addition to the abnormal interstitial pulmonary pattern, areas of pulmonary consolidation were evident caudodorsally in seven horses. Other thoracic radiographic features included: hilar lymphadenopathy (4 horses), pleural effusion/thickening (4), cranial mediastinal lymphadenopathy (2), hyperinflation (1), and a discrete pulmonary mass (1). Necropsy findings in eight horses and results of lung biopsies in an additional five horses showed a diffuse, multifocal, granulomatous pneumonia with areas of pulmonary fibrosis. Cellular infiltrates included predominantly macrophages with intracellular and/or extracellular crystalline material, occasional lymphocytes, and giant cells. Similar cellular changes were also identified, during necropsy, in the hilar and tracheobronchial lymph nodes in each of the eight horses, although gross enlargement of the lymph nodes was present in only six horses. The radiographic and pathologic findings of these 19 horses are consistent with chronic or the accelerated forms of silicosis that are recognized in humans. PMID:1941758

  9. The Impact of Radiographic Retropharyngeal Adenopathy in Oropharyngeal Cancer

    PubMed Central

    Gunn, G. Brandon; Debnam, J. Matthew; Fuller, Clifton D.; Morrison, William H.; Frank, Steven J.; Beadle, Beth M.; Sturgis, Erich M.; Glisson, Bonnie S.; Phan, Jack; Rosenthal, David I.; Garden, Adam S.

    2013-01-01

    Background We carried out this study to define the incidence of radiographic retropharyngeal lymph node (RPLN) involvement in oropharyngeal cancer (OPC) and its impact on clinical outcomes, which have not been well established to date. Methods Our departmental database was queried for patients irradiated for OPC from 2001–2007. Analyzable patients were those with imaging data available for review to determine radiographic RPLN status. Demographic, clinical, and outcomes data were retrieved and analyzed. Results The cohort consisted of 981 patients. Median follow up was 69 months. The base of tongue (47%) and tonsil (46%) were the most common primary sites. The majority of patients had T1-2 primaries (64%) and 94% stage 3-4B disease. IMRT was used in 77%, and systemic therapy was delivered to 58%. The incidence of radiographic RPLN involvement was 10% and highest for pharyngeal wall (23%) and lowest for base of tongue tumors (6%). RPLN adenopathy correlated with a number of patient and tumor factors. RPLN involvement was associated with poorer 5-year outcomes on univariate analysis (p <.001 for all): local control (79% vs. 92%), nodal control (80% vs. 93%), recurrence-free (51% vs. 81%), distant metastases-free (66% vs. 89%), and overall survival (52% vs. 82%), and maintained significance for local control (p=.023), recurrence-free (p=.001), distant metastases-free (p=.003), and overall survival (p=.001) on multivariate analysis. Conclusions In this cohort of nearly 1000 patients investigating radiographic RPLN adenopathy in OPC, RPLN involvement was observed in 10% of patients and portends a negative influence on disease recurrence, distant relapse, and survival. PMID:23733178

  10. Imaging of adult flatfoot: correlation of radiographic measurements with MRI.

    PubMed

    Lin, Yu-Ching; Mhuircheartaigh, Jennifer Ni; Lamb, Joshua; Kung, Justin W; Yablon, Corrie M; Wu, Jim S

    2015-02-01

    OBJECTIVE. The purpose of this study is to determine whether radiographic foot measurements can predict injury of the posterior tibial tendon (PTT) and the supporting structures of the medial longitudinal arch as diagnosed on MRI. MATERIALS AND METHODS. After institutional review board approval, 100 consecutive patients with radiographic and MRI examinations performed within a 2-month period were enrolled. Thirty-one patients had PTT dysfunction clinically, and 69 patients had other causes of ankle pain. Talonavicular uncoverage angle, incongruency angle, calcaneal pitch angle, Meary angle, cuneiform-to-fifth metatarsal height, and talar tilt were calculated on standing foot or ankle radiographs. MRI was used to assess for abnormalities of the PTT (tenosynovitis, tendinosis, and tear) and supporting structures of the medial longitudinal arch (spring ligament, deltoid ligament, and sinus tarsi). Statistical analysis was performed using the chi-square and Fisher exact tests for categoric variables; the Student t test was used for continuous variables. RESULTS. There was a statistically significant association of PTT tear with abnormal talonavicular uncoverage angle, calcaneal pitch angle, Meary angle, and cuneiform-to-fifth metatarsal height. PTT tendinosis and isolated tenosynovitis had a poor association with most radiologic measurements. If both calcaneal pitch and Meary angles were normal, no PTT tear was present. An abnormal calcaneal pitch angle had the best association with injury to the supporting medial longitudinal arch structures. CONCLUSION. Radiographic measurements, especially calcaneal pitch and Meary angles, can be useful in detecting PTT tears. Calcaneal pitch angle provides the best assessment of injury to the supporting structures of the medial longitudinal arch.

  11. Kniest dysplasia: MR correlation of histologic and radiographic peculiarities.

    PubMed

    Dwek, Jerry R

    2005-02-01

    Unossified epiphyses of Kniest dysplasia patients histologically reveal a bizarre pattern of chondrocytes lying amid a highly vacuolated matrix giving rise to the name "Swiss cheese" cartilage. The ossified epiphyses also are unusual in showing clouds of dense punctate calcifications randomly distributed throughout. Both unossified and ossified epiphyses reveal on MR imaging a similar pattern of lakes of bright T2 signal against a relatively normal background, which represents an interesting analogue to the histologic and radiographic features.

  12. Radiographic abnormalities and mortality in subjects with exposure to crocidolite.

    PubMed

    de Klerk, N H; Musk, A W; Cookson, W O; Glancy, J J; Hobbs, M S

    1993-10-01

    Plain chest radiographs from a one in six random sample of the workforce of the asbestos industry at Wittenoom, Western Australia between 1943 and 1966 have been classified for degree of profusion and pleural thickening by two independent observers according to the 1980 UICC-ILO Classification of Radiographs for the pneumoconioses to clarify the effect of degree of radiological abnormality on survival. A total of 1106 subjects were selected. Each subject's age, cumulative exposure to crocidolite, and time since first exposure were determined from employment records, the results of a survey of airborne concentrations of fibres > 5 mu in length conducted in 1966, and an exposure rating by an industrial hygienist and an ex-manager of the mine and mill at Wittenoom. By the end of 1986 193 subjects had died. Conditional logistic regression was used to model the relative risk of death in five separate case-control analyses in which the outcomes were deaths from: (1) all causes, (2) malignant mesothelioma, (3) lung cancer, (4) asbestosis, and (5) other causes excluding cancer and asbestosis. Up to 20 controls per case were randomly chosen from all men of the same age who were not known to have died before the date of death of the index case. After adjustment for exposure and time since first exposure, there were significant and independent effects of radiographic profusion and pleural thickening on all cause mortality. The effect of profusion was largely a result of the effect on mortality from malignant mesothelioma and asbestosis but not lung cancer. The effect of pleural thickening was greatest on mortality from other causes, mainly ischaemic heart disease. This study has shown that degree of radiographic abnormality has an independent effect on mortality from malignant mesothelioma, asbestosis, and all causes even after allowing for the effects of age, degree of exposure, and time since first exposure.

  13. Radiographic Images Produced by Cosmic-Ray Muons

    NASA Astrophysics Data System (ADS)

    Alfaro, Rubén

    2006-09-01

    An application of high energy physics instrumentation is to look for structure or different densities (materials) hidden in a matrix (tons) of material. By tracing muons produced by primary Cosmic Rays, it has been possible to generate a kind of radiographs which shows the inner structure of dense containers, monuments or mountains. In this paper I review the basics principles of such techniques with emphasis in the Sun Pyramid project, carried out by IFUNAM in collaboration with Instituto Nacioanal de Antropologia e Historia.

  14. Sensitometric properties of radiographic films and film classification

    NASA Astrophysics Data System (ADS)

    Siidorow, A.

    An attempt was made to elucidate those film characteristics which affect the radiographic image quality and which could be used as the basis of film classification. A literary survey showed that it is apparently impossible to measure the most important film characteristics, i.e., graininess and granularity, in a reliable and simple way. An existing classification method based on a visual comparison of film graininess is recommended.

  15. A cryogenic dose calorimeter for pulsed radiographic machines

    SciTech Connect

    Watson, S.; Mueller, K.; Kauppila, T.

    1995-05-05

    Calorimetry is the most direct, absolute technique for absorbed dose measurements. To improve the measurement accuracy for use with quantitative radiography, a calorimeter has been developed for LANL`s pulsed radiographic machines which produce bremsstrahlung radiation fields of 50--200 Rad per pulse at 1 meter from the source. This paper describes the theory of operation, the calorimeter design, and presents results from the PHERMEX accelerator. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  16. A cryogenic dose calorimeter for pulsed radiographic accelerators

    SciTech Connect

    Watson, S.A.; Kauppila, T.; Mueller, K.H.

    1994-10-01

    Calorimetry is the most direct, absolute technique for absorbed dose measurements. To improve the measurement accuracy for use with quantitative radiography, a calorimeter has been developed for LANL`s pulsed radiographic machines which produce Bremsstrahlung radiation fields of 50-200 Rad per pulse at 1 meter from the source. This paper describes the theory of operation, the calorimeter design, and presents results from the PHERMEX accelerator.

  17. The swallowed toothbrush: a radiographic clue of bulimia.

    PubMed

    Riddlesberger, M M; Cohen, H L; Glick, P L

    1991-01-01

    Swallowed toothbrushes were noted in the esophagus of one teenager and the stomach of two others with bulimia. The presence of a toothbrush in the lumen of the gastrointestinal tract should make the radiologist suspicious of bulimia/anorexia nervosa. A toothbrush shows a characteristic radiographic image with parallel rows of short metallic radiodensities due to the metallic plates that hold the bristles in place.

  18. Age estimation based on Kvaal's technique using digital panoramic radiographs

    PubMed Central

    Mittal, Samta; Nagendrareddy, Suma Gundareddy; Sharma, Manisha Lakhanpal; Agnihotri, Poornapragna; Chaudhary, Sunil; Dhillon, Manu

    2016-01-01

    Introduction: Age estimation is important for administrative and ethical reasons and also because of legal consequences. Dental pulp undergoes regression in size with increasing age due to secondary dentin deposition and can be used as a parameter of age estimation even beyond 25 years of age. Kvaal et al. developed a method for chronological age estimation based on the pulp size using periapical dental radiographs. There is a need for testing this method of age estimation in the Indian population using simple tools like digital imaging on living individuals not requiring extraction of teeth. Aims and Objectives: Estimation of the chronological age of subjects by Kvaal's method using digital panoramic radiographs and also testing the validity of regression equations as given by Kvaal et al. Materials and Methods: The study sample included a total of 152 subjects in the age group of 14-60 years. Measurements were performed on the standardized digital panoramic radiographs based on Kvaal's method. Different regression formulae were derived and the age was assessed. The assessed age was then correlated to the actual age of the patient using Student's t-test. Results: No significant difference between the mean of the chronological age and the estimated age was observed. However, the values of the mean age estimated by using regression equations as given previously in the study of Kvaal et al. significantly underestimated the chronological age in the present study sample. Conclusion: The results of the study give an inference for the feasibility of this technique by calculation of regression equations on digital panoramic radiographs. However, it negates the applicability of same regression equations as given by Kvaal et al. on the study population. PMID:27555738

  19. Electron beam spot size stabilization for radiographic application

    SciTech Connect

    Kwan, T.J.T.; Snell, C.M.

    1998-12-31

    The authors have demonstrated through computer simulations that self-biasing the target can effectively control the ion column which causes radial pinching of the electron beam, resulting in the growth of spot size on target. This method has the unique features in simplicity and non-intrusiveness in its implementation into radiographic systems. The concept is being actively explored experimentally at the Integrated Test Stand (ITS).

  20. Direct characterization of hydrodynamic loading on a microelectromechanical systems microstructure

    NASA Astrophysics Data System (ADS)

    Mehrnezhad, Ali; Bashir, Rashid; Park, Kidong

    2016-03-01

    Hydrodynamic loading greatly affects resonant characteristic of microfabricated structures immersed in a viscous fluid. In this letter, we demonstrate a technique to measure hydrodynamic loading on a MEMS resonator in a broad range of actuation frequency. The extracted hydrodynamic loading is in a good agreement with an analytical solution of an oscillating sphere, and a highly accurate model is developed for the hydrodynamic loading of the resonator. The developed technique can directly characterize the hydrodynamic loading of a microstructure with an arbitrary geometry and will facilitate the optimization of MEMS devices and AFM probes operating in a viscous fluid.

  1. Preasymptotic hydrodynamic dispersion as a quantitative probe of permeability.

    PubMed

    Brosten, Tyler R; Vogt, Sarah J; Seymour, Joseph D; Codd, Sarah L; Maier, Robert S

    2012-04-01

    We interpret a generalized short-time expansion of stochastic hydrodynamic dispersion dynamics in the case of small Reynolds number flow through macroscopically homogenous permeable porous media to directly determine hydrodynamic permeability. The approach allows determination of hydrodynamic permeability from pulsed field gradient spin-echo nuclear magnetic resonance measurement of the short-time effective hydrodynamic dispersion coefficient. The analytical expansion of asymptotic dynamics agrees with experimental NMR data and lattice Boltzmann simulation of hydrodynamic dispersion in consolidated random sphere pack media. PMID:22680531

  2. Digital intraoral radiographic quality assurance and control in private practice.

    PubMed

    Walker, Timothy F; Mah, Peter; Dove, S Brent; McDavid, W Doss

    2014-01-01

    At present, the American Dental Association and the American Academy of Oral Maxillofacial Radiology have guidelines for the dental environment that include quality assurance and control of film-based radiography. Approximately 19%-30% of US dental offices currently use some form of digital intraoral radiography, and growth is expected to continue. It is anticipated that new tools and guidelines will be needed to aid in the development of quality assurance (QA) and control of digital intraoral radiographic images. Working with a representative sample of private practice dental offices, this study examined and evaluated the entire digital intraoral radiographic system used in each operatory. The X-ray machine was tested for equipment performance and accuracy, and the computer monitor calibration was evaluated and adjusted as needed. The results confirm the continued need for updated QA procedures in the dental office that include digital X-ray imaging. By implementing these changes and practices, dentists should be able to improve the diagnostic quality of radiographs while reducing the radiation exposure of the patient.

  3. The impact of work rewards on radiographers' organizational commitment.

    PubMed

    Akroyd, D; Mulkey, W; Utley-Smith, Q

    1995-01-01

    Organizational commitment is an affective work outcome that has been used to predict work-related behaviors such as turnover, absenteeism and intent-to-leave. There has been little research in organizational commitment for the allied health professions and no empirical studies in the radiologic sciences. The purpose of this study was to examine the predictive value of selected intrinsic and extrinsic work reward variables--involvement, significance, autonomy, general working conditions, supervision and salary--on staff radiographers' organizational commitment. In this study of 600 full-time staff radiographers in North and South Carolina, supervision (for ages 20-37 years) and involvement (for ages 38-66 years) were significant predictors of organizational commitment. The results of the study indicate that healthcare organizations should provide potential supervisors with managerial training, especially for radiographers who move to supervisory positions based on clinical skills and years of experience. In the long run, such programs are much less expensive than costs associated with replacing employees who leave the organization because of low organizational commitment. Also, management strategies and programs to redesign and enhance job tasks may help maintain or increase organizational commitment. PMID:10143137

  4. Compliance of Michigan dentists with radiographic safety recommendations

    SciTech Connect

    Nakfoor, C.A.; Brooks, S.L. )

    1992-04-01

    We surveyed a random sample of 398 Michigan dentists in private practice to determine their compliance with the American Dental Association Council's recommendations for radiographic equipment and techniques. The response rate was 67% of the questionnaires delivered successfully. The majority of dentists use only D-speed film (73%) and round collimation of the x-ray beam (90%). Only 5% have an x-ray machine equipped with a rectangular collimator and 18% have at least one machine with a pointed cone. Leaded apron use is almost universal, but only 49% of the dentists use cervical collars in addition to the apron. The majority of dentists surveyed do not comply with the American Dental Association Council's recommendations on film speed, collimation, and use of leaded cervical collar. Using effective dose equivalents determined by Gibbs et al. for a variety of radiographic techniques, we estimate that an eight-fold reduction in radiation dose could be achieved without eliminating a single radiograph if all dentists used E-speed film and collimation of the beam to the size of the film.

  5. Radiographic reference limits for cardiac width of budgerigars (Melopsittacus undulatus).

    PubMed

    Velayati, Mozhgan; Mirshahi, Ali; Razmyar, Jamshid; Azizzadeh, Mohammad

    2015-03-01

    Primary and secondary cardiovascular diseases are not uncommon in birds. Although radiologic standards for heart width have been developed for mammals, they are still not available for many avian species. The purpose of this study was to establish normal reference values for cardiac size in budgerigar (Melopsittacus undulatus), one of the most popular pet bird species all over the world. After clinical and radiographic (lateral and ventrodorsal views) evaluations, 27 adult, clinically healthy budgerigars (10 females and 17 males) were included in this study. High-quality ventrodorsal and lateral radiographic projections were obtained. The cardiac and thoracic width, distance between third and fourth ribs, synsacrum width, coracoid width, and the distance between clavicle bones were measured on ventrodorsal radiographs. The ratio between cardiac width and other mentioned indices was calculated. Correlation of each anatomical index with the cardiac width was evaluated by linear regression model. Sex and weight were included in all models. Mean + SD of cardiac width was 10.8 +/- 0.6 mm, with lower and upper limits of 9.5 and 12.0 mm. The results showed a significant correlation between the cardiac width and the thoracic width (R2 = 0.28; P = 0.005). There were no significant associations between weight, sex, and the heart width. The values and ratios obtained in this study can be used as a reference of normal cardiac size of budgerigar in radiology for detection of cardiomegaly in this bird. PMID:25831574

  6. Radiographic assessment of impacted teeth and associated pathosis prevalence

    PubMed Central

    El-Khateeb, Sara M.; Arnout, Eman A.; Hifnawy, Tamer

    2015-01-01

    Objectives: To assess the prevalence of both impaction and associated pathosis in a Saudi population in Al-Madinah, Saudi Arabia based on digital panoramic radiographs. Methods: This study was carried out from December 2013 to February 2015. Panoramic radiographs of 359 male patients attending the Oral Diagnosis Clinics, Faculty of Dentistry, Taibah University, Al-Madinah, Saudi Arabia were reviewed. All images were evaluated to determine the prevalence and pattern of impacted third molars and canines, and associated pathosis. Results: Among 359 panoramic radiographs examined, 124 patients had impacted teeth. The impacted mandibular third molars were the most prevalent impacted teeth, 77.6% had class II pattern of impaction. Among the impacted maxillary canines, 75% were mesioangular and among 66 impacted maxillary third molars, 63.6% had class C. Our study showed that 5.8% of Saudi patients had 3 or more impacted teeth, 13.1% had 2 impacted teeth, and 15.6% had one impacted tooth. Associated pathosis was found in 18.2% among impacted maxillary third molars, and 31.5% among impacted mandibular third molars. The incidence of impaction decreases with age. Conclusion: The prevalence and pattern of impacted third molars among Saudis are almost similar to other racial populations. The number of missing wisdom increases with age. Although the percentage of pathosis associated with impaction was considerably low, it is essential to carry you regular oral examinations to preserve asymptomatic impacted teeth in good health. PMID:26219449

  7. Reliability of panoramic radiographs for identifying supernumerary teeth in children.

    PubMed

    Anthonappa, Robert P; King, Nigel M; Rabie, A Bakr M; Mallineni, Sreekanth K

    2012-01-01

    OBJECTIVES. To evaluate the reliability of panoramic radiographs (PRs) for identifying supernumerary teeth (ST) and to determine whether the level of dental training of the observer influenced the identification of ST. METHODS. Seventy-five PRs were randomly selected from the patient records and 18 examiners independently rated 25 radiographs each, for specific risk factors as well as for a measure of adequacy. Subsequently, the results were paired with those of the other examiners who assessed the same set of PRs. Descriptive statistics were computed using Fisher's exact test, and kappa statistics were used to assess the inter- and intra-observer reliability. RESULTS. Four hundred and fifty PRs were available for analysis. The overall sensitivity and specificity figures were 50% and 98.3%, whereas the positive and negative predictive values were 90.6% and 83.6%, respectively. The sensitivity figures for Junior House Dental Officers and Postgraduate Paediatric Dental Trainees were 39.2% and 60.8%, whereas the specificity figures were 99.4% and 95% with slight inter-examiner and moderate intra-examiner reliability. CONCLUSIONS. Panoramic radiographs are unreliable for identifying ST, and higher level of dental training is essential for identifying ST. PMID:21740473

  8. Application of Perona Malik anisotropic diffusion on digital radiographic image

    SciTech Connect

    Halim, Suhaila Abd; Razak, Rohayu Abdul; Ibrahim, Arsmah; Manurung, Yupiter HP

    2014-07-10

    Perona Malik Anisotropic Diffusion (PMAD) is a very useful and efficient denoising technique if the parameters are properly selected. Overestimating the parameters may cause oversmoothed and underestimating it may leave unfiltered noise. This makes the selection of parameters a crucial process. In this paper the PMAD model is solved using a finite difference scheme The discretized model is evaluated using different diffusion coefficient of exponential and quadratic on defective radiographic images in terms of quality and efficiency. In the application of the PMAD model on image data, a set of defective radiographic images of welding is used as input data. Peak Signal to Noise Ratio (PSNR), Structural Similarity Measure (SSIM) and temporal time are used to evaluate the performance of the model. The implementation of the experiment has been carried out using MATLAB R2009a. In terms of quality, results show that the Quadratic Diffusion Coefficient Function (QDCF) provides better results compared with the Exponential Diffusion Coefficient Function (EDCF). In conclusion, the denoising effect using PMAD model based on finite difference scheme shows able to improve image quality by removing noise in the defective radiographic image.

  9. A benchmark concept for simulation in radiographic testing

    SciTech Connect

    Ewert, U.; Deresch, A.; Bellon, C.; Jaenisch, G.-R.

    2014-02-18

    The new standard ISO 17636–2:2013 “NDT of welds: Radiographic testing - Part 2: X- and gamma ray techniques with digital detectors” describes a complex procedure for film replacement by phosphor imaging plates and digital detector arrays. RT modeling software should consider these detector types, X-ray film, and the standard requirements for image quality. Practitioners expect the same visibility of image quality indicators (IQI) in the simulated radiographs as in the experimental exposures. The proposed benchmark test is based on the comparison of experimental radiographs taken at BAM with modeled ones of participants. The experimental setup and the determination of the equivalent penetrameter sensitivity (EPS) as described in the procedure of ASTM E 746 are used for quantitative evaluation of the achievable contrast sensitivity for step hole IQIs as considered in Annex B of ISO 17636–2. System classification data for Computed Radiography (CR) and film systems will be provided by BAM according to ISO 11699–1 for selected film systems and according to ASTM E 2446 for selected CR systems. The classification of films and digital detectors is based on the measurement of the dose response function, the basic spatial resolution (SR{sub b}) of the image, and the measured image noise, which depends on the detector efficiency, the quantum statistics, and the detector fixed pattern noise.

  10. Measuring X-ray Spectra of Flash Radiographic Sources

    NASA Astrophysics Data System (ADS)

    Gehring, Amanda; Espy, Michelle; Haines, Todd; Mendez, Jacob; Moir, David; Sedillo, Robert; Volegov, Petr; Webb, Tim

    2015-10-01

    A Compton spectrometer has been re-commissioned for measurements of flash radiographic sources. The determination of the energy spectrum provides information about the x-ray production mechanisms of these sources (ie. reaction history of plasmas, electron-target interactions) and benefits the analysis of images obtained at radiographic facilities. However, the measurements of the spectra are difficult due to the high count rates and short nature of the pulses (~ 50 ns). The spectrometer is a 300 kg neodymium-iron magnet which measures spectra in the <1 MeV to 20 MeV energy range. Incoming x-rays are collimated into a narrow beam incident on a converter foil. The ejected Compton electrons are collimated so that the forward-directed electrons enter the magnetic field region of the spectrometer. The position of the electrons at the focal plane of the magnet is a function of their momentum, allowing the x-ray spectrum to be reconstructed. Recent measurements of both flash and continuous radiographic sources will be presented.

  11. Rapid Skeletal Turnover In A Radiographic Mimic Of Osteopetrosis

    PubMed Central

    Whyte, Michael P.; Madson, Katherine L.; Mumm, Steven; McAlister, William H.; Novack, Deborah V.; Blair, Jo C.; Helliwell, Timothy R.; Stolina, Marina; Abernethy, Laurence J.; Shaw, Nicholas J.

    2015-01-01

    Among the high bone mass disorders, the osteopetroses reflect osteoclast failure that prevents skeletal resorption and turnover leading to reduced bone growth and modeling and characteristic histopathological and radiographic findings. We report an 11-year-old boy with a new syndrome that radiographically mimics osteopetrosis but features rapid skeletal turnover. He presented at age 21 months with a parasellar, osteoclast-rich giant cell granuloma. Radiographs showed a dense skull, generalized osteosclerosis, and cortical thickening, medullary cavity narrowing, and diminished modeling of tubular bones. His serum alkaline phosphatase was > 5,000 IU/L (normal < 850). After partial resection, the granuloma re-grew but then regressed and stabilized during three years of uncomplicated pamidronate treatment. His hyperphosphatasemia transiently diminished but all bone turnover markers, especially those of apposition, remained elevated. Two years after pamidronate therapy stopped, BMD z-scores reached + 9.1 and + 5.8 in the lumbar spine and hip, respectively, and iliac crest histopathology confirmed rapid bone remodeling. Serum multiplex biomarker profiling was striking for low sclerostin. Mutation analysis was negative for activation of LRP4, LRP5, or TGFβ1 and for defective SOST, OPG, RANKL, RANK, SQSTM1, or sFRP1. Microarray showed no notable copy number variation. Studies of his non-consanguineous parents were unremarkable. The etiology and pathogenesis of this unique syndrome are unknown. PMID:24919763

  12. Distal Radius Radiographic Indices and Perilunate Fracture Dislocation

    PubMed Central

    Bagherifard, Abolfazl; Jafari, Davod; Keihan Shokouh, Hassan; Motavallian, Ebrahim; Najd Mazhar, Farid

    2016-01-01

    Background Distal radius radiographic indices may play a role as risk factors in pathogenesis of Kienbock’s disease, scaphoid fracture and nonunion. Perilunate fracture dislocations are devastating wrist injuries, and their relationship and distal radius indices have not been addressed in the literature. Objectives The aim of this study was to evaluate the possible role of distal radius radiographic indices including radial height, radial inclination, ulnar variance and volar tilt as risk factors in the perilunate fracture dislocation injury of the wrist. Patients and Methods We studied distal radius radiographic indices including radial height, radial inclination, ulnar variance and volar tilt in 43 patients with perilunate fracture dislocations and compared them with 44 wrists in the control group. Results The mean values of the radial height, radial inclination, ulnar variance and volar tilt were 12.74 (5 - 18), 24.20 (7 - 35), -0.73 (-5 - 4) and 12.28 (2 - 20) in the patient group. These values were 12.68 (9 - 22), 23.22 (17 - 30), -0.11 (-4 - 3) and 11.05 (-3 - 20), respectively in the control group. There was no statistically significant difference between the two groups. Conclusions This study did not show that distal radius anatomical indices including the radial height, radial inclination, ulnar variance and volar tilt influence perilunate fracture dislocation as risk factors.

  13. Computer-aided assessment of scoliosis on posteroanterior radiographs.

    PubMed

    Zhang, Junhua; Lou, Edmond; Hill, Douglas L; Raso, James V; Wang, Yuanyuan; Le, Lawrence H; Shi, Xinling

    2010-02-01

    In order to reduce the observer variability in radiographic scoliosis assessment, a computer-aided system was developed. The system semi-automatically measured the Cobb angle and vertebral rotation on posteroanterior radiographs based on Hough transform and snake model, respectively. Both algorithms were integrated with the shape priors to improve the performance. The system was tested twice by each of three observers. The intraobserver and interobserver reliability analyses resulted in the intraclass correlation coefficients higher than 0.9 and 0.8 for Cobb measurement on 70 radiographs and rotation measurement on 156 vertebrae, respectively. Both the Cobb and rotation measurements resulted in the average intraobserver and interobserver errors less than 2 degrees and 3 degrees , respectively. There were no significant differences in the measurement variability between groups of curve location, curve magnitude, observer experience, and vertebra location. Compared with the documented results, measurement variability is reduced by using the developed system. This system can help orthopedic surgeons assess scoliosis more reliably.

  14. Hindfoot Deformity Corrected With Double Versus Triple Arthrodesis: Radiographic Comparison.

    PubMed

    DeVries, J George; Scharer, Brandon

    2015-01-01

    Hindfoot fusion is capable of correcting hindfoot deformities. Typically, this has been done through triple arthrodesis. Recently, there has been some discussion of a double arthrodesis, sparing the calcaneocuboid joint. We compared the radiographic corrective ability of these 2 fusion techniques. A retrospective radiographic review was performed of 20 consecutive triple arthrodeses (triple) and 20 consecutive talonavicular and subtalar arthrodesis with calcaneocuboid preservation (double). Additional midfoot arthrodesis or osteotomy was performed as needed in each group. The preoperative measurements were compared to those from standing weightbearing films after fusion postoperatively. The angular measurements included the anteroposterior and lateral talar–first metatarsal line (Meary's and Simmons) and the anteroposterior and lateral talocalcaneal angle. Both groups demonstrated a statistically significant reduction in deformity and a return to more normal radiographic findings after arthrodesis (p < .05). The 2 groups did not differ statistically in preoperative deformity or correction obtained (p > .05). Traditionally, triple arthrodesis has been advocated for significant hindfoot deformity that is irreducible. Recent studies have questioned the need for inclusion of the calcaneocuboid joint in the arthrodesis, in particular, in a pronated, valgus-type foot. In addition, others have advocated a strictly medial approach to hindfoot fusion, necessarily avoiding the calcaneocuboid joint. Our findings agree with the assertion that hindfoot deformity can be adequately and reliably corrected through hindfoot arthrodesis whether or not the calcaneocuboid joint is included. PMID:25432460

  15. Geometrical theory of aberrations near the axis in classical off-axis reflecting telescopes.

    PubMed

    Chang, Seunghyuk; Prata, Aluizio

    2005-11-01

    A geometrical theory of aberrations for the vicinity of the focus of arbitrary off-axis sections of conic mirrors is derived. It is shown that an off-axis conic mirror introduces linear astigmatism in the image. However, in classical two-mirror telescopes this aberration can be eliminated by tilting the secondary parent mirror axis. It is also shown that the practical geometrical-optics performance of a classical off-axis two-mirror telescope with no linear astigmatism is equivalent to the performance of an on-axis system, proving that both systems have identical third-order coma. To demonstrate the applicability of the theory developed in a practical system, a fast (i.e., f/2), compact, obstruction-free classical off-axis Cassegrain telescope is designed.

  16. Hydrodynamic Instabilities in Blast-Driven Systems

    NASA Astrophysics Data System (ADS)

    Henry de Frahan, Marc; Johnsen, Eric

    2014-11-01

    Mixing from hydrodynamics instabilities such as Richtmyer-Meshkov, Rayleigh-Taylor, and Kelvin-Helmholtz, occurs in a wide range of engineering applications such as inertial confinement fusion, supernova collapse, and scramjet combustion. The success of these applications depends on an accurate understanding of these phenomena. Following previous work investigating hydrodynamic mixing from the interaction of a perturbed interface with a planar blast wave, we model the perturbation growth by analyzing the different acceleration phases of a blast wave: an instantaneous acceleration (a pressure increase) followed by a gradual, time-dependent deceleration (a pressure decrease). Depending on the characteristics of these phases, the instability will be dominated by Richtmyer-Meshkov or Rayleigh-Taylor growth. We use a high-order accurate Discontinuous Galerkin method that prevents pressure errors at interfaces with variable specific heats ratios to simulate these systems and understand the different growth regimes.

  17. Hydrodynamics with spin in bacterial suspensions

    NASA Astrophysics Data System (ADS)

    Belovs, M.; CÄ`bers, A.

    2016-06-01

    We describe a kind of self-propelling motion of bacteria based on the cooperative action of rotating flagella on the surface of bacteria. Describing the ensemble of rotating flagella in the framework of the hydrodynamics with spin, the reciprocal theorem of Stokesian hydrodynamics is generalized accordingly. The velocity of the self-propulsion is expressed in terms of the characteristics of the vector field of flagella orientation and it is shown that the unusually high velocities of Thiovulum majus bacteria may be explained by the cooperative action of the rotating flagella. The expressions obtained enable us to estimate the torque created by the rotary motors of the bacterium and show quantitative agreement with the existing experimental data.

  18. A Hydrodynamical Mechanism for Generating Astrophysical Jets

    NASA Astrophysics Data System (ADS)

    Hernández, X.; Rendón, P. L.; Rodríguez-Mota, R. G.; Capella, A.

    2014-04-01

    Whenever in a classical accretion disk the thin disk approximation fails interior to a certain radius, a transition from Keplerian to radial infalling trajectories should occur. We show that this transition is actually expected to occur interior to a certain critical radius, provided surface density profiles are steeper than Sigma(R) ~ R(-1/2) , and further, that it probably corresponds to the observationally inferred phenomena of thick hot walls internally limiting the extent of many stellar accretion disks. Infalling trajectories will lead to the convergent focusing and concentration of matter towards the very central regions, most of which will simply be swallowed by the central object. We show through a perturbative hydrodynamical analysis, that this will naturally develop a well collimated pair of polar jets. A first analytic treatment of the problem described is given, proving the feasibility of purely hydrodynamical mechanisms for astrophysical jet generation.

  19. Hydrodynamics of ultra-relativistic bubble walls

    NASA Astrophysics Data System (ADS)

    Leitao, Leonardo; Mégevand, Ariel

    2016-04-01

    In cosmological first-order phase transitions, gravitational waves are generated by the collisions of bubble walls and by the bulk motions caused in the fluid. A sizeable signal may result from fast-moving walls. In this work we study the hydrodynamics associated to the fastest propagation modes, namely, ultra-relativistic detonations and runaway solutions. We compute the energy injected by the phase transition into the fluid and the energy which accumulates in the bubble walls. We provide analytic approximations and fits as functions of the net force acting on the wall, which can be readily evaluated for specific models. We also study the back-reaction of hydrodynamics on the wall motion, and we discuss the extrapolation of the friction force away from the ultra-relativistic limit. We use these results to estimate the gravitational wave signal from detonations and runaway walls.

  20. Hydrodynamic approach to boost invariant free streaming

    NASA Astrophysics Data System (ADS)

    Calzetta, E.

    2015-08-01

    We consider a family of exact boost invariant solutions of the transport equation for free-streaming massless particles, where the one-particle distribution function is defined in terms of a function of a single variable. The evolution of second and third moments of the one-particle distribution function [the second moment being the energy momentum tensor (EMT) and the third moment the nonequilibrium current (NEC)] depends only on two moments of that function. Given those two moments, we show how to build a nonlinear hydrodynamic theory which reproduces the early time evolution of the EMT and the NEC. The structure of these theories may give insight on nonlinear hydrodynamic phenomena on short time scales.

  1. Pursuit and Synchronization in Hydrodynamic Dipoles

    NASA Astrophysics Data System (ADS)

    Kanso, Eva; Tsang, Alan Cheng Hou

    2015-10-01

    We study theoretically the behavior of a class of hydrodynamic dipoles. This study is motivated by recent experiments on synthetic and biological swimmers in microfluidic Hele-Shaw type geometries. Under such confinement, a swimmer's hydrodynamic signature is that of a potential source dipole, and the long-range interactions among swimmers are obtained from the superposition of dipole singularities. Here, we recall the equations governing the positions and orientations of interacting asymmetric swimmers in doubly periodic domains and focus on the dynamics of pairs of swimmers. We obtain two families of "relative equilibria"-type solutions that correspond to pursuit and synchronization of the two swimmers. Interestingly, the pursuit mode is stable for large-tail swimmers, whereas the synchronization mode is stable for large-head swimmers. These results have profound implications on the collective behavior reported in several recent studies on populations of confined microswimmers.

  2. Structure and hydrodynamics of colloidal systems

    NASA Astrophysics Data System (ADS)

    Hayter, John B.

    1986-02-01

    Invited paperColloidal phases (for example, micellar solutions, latex suspensions, ferrofluids and microemulsions) provide excellent model systems with which to test structural and hydrodynamic theories of the liquid state. Interparticle potentials may be attractive or repulsive, and the experimentalist is often free to control the strength, range and symmetry of the interactions. Small-angle neutron scattering (SANS) and small-angle neutron spin-echo (SANSE) provide excellent complementary tools for studying the structure and time-dependence of these systems, where correlation lengths typically vary from about one to several tens of nm. Correlation times are usually in the nsec to μsec range, but may be of order minutes in certain systems. This paper will review some of the current theories and their recent experimental tests, using colloidal systems in which the direct interaction potentials may have spherical, dipolar or cylindrical symmetry and the hydrodynamic interactions may be weak or strong.

  3. Structure and hydrodynamics of colloidal systems

    NASA Astrophysics Data System (ADS)

    Hayter, J. B.

    1985-07-01

    Colloidal phases (for example, micellar solutions, latex suspensions, ferrofluids and microemulsions) provide excellent model systems with which to test structural and hydrodynamic theories of the liquid state. Interparticle potentials may be attractive or repulsive, and the experimentalist is often free to control the strength, range and symmetry of the interactions. Small-angle neutron scattering (SANS) and small-angle neutron spin-echo (SANSE) provide excellent complementary tools for studying the structure and time-dependence of these systems, where correlation lengths typically vary from about one to several tens of nm. Correlation times are usually in the nsec to (MU) sec range, but may be of order minutes in certain systems. This paper will review some of the current theories and their recent experimental tests, using colloidal systems in which the direct interaction potentials may have spherical, dipolar or cylindrical symmetry and the hydrodynamic interactions may be weak or strong.

  4. Quasinormal modes of the polytropic hydrodynamic vortex

    NASA Astrophysics Data System (ADS)

    Oliveira, Leandro A.; Cardoso, Vitor; Crispino, Luís C. B.

    2015-07-01

    Analogue systems are a powerful instrument to investigate and understand in a controlled setting many general-relativistic effects. Here, we focus on superradiant-triggered instabilities and quasinormal modes. We consider a compressible hydrodynamic vortex characterized by a polytropic equation of state, the polytropic hydrodynamic vortex, a purely circulating system with an ergoregion but no event horizon. We compute the quasinormal modes of this system numerically with different methods, finding excellent agreement between them. When the fluid velocity is larger than the speed of sound, an ergoregion appears in the effective spacetime, triggering an "ergoregion instability." We study the details of the instability for the polytropic vortex, and in particular find analytic expressions for the marginally stable configuration.

  5. Electro-hydrodynamic synchronization of piezoelectric flags

    NASA Astrophysics Data System (ADS)

    Xia, Yifan; Doaré, Olivier; Michelin, Sébastien

    2016-08-01

    Hydrodynamic coupling of flexible flags in axial flows may profoundly influence their flapping dynamics, in particular driving their synchronization. This work investigates the effect of such coupling on the harvesting efficiency of coupled piezoelectric flags, that convert their periodic deformation into an electrical current. Considering two flags connected to a single output circuit, we investigate using numerical simulations the relative importance of hydrodynamic coupling to electrodynamic coupling of the flags through the output circuit due to the inverse piezoelectric effect. It is shown that electrodynamic coupling is dominant beyond a critical distance, and induces a synchronization of the flags' motion resulting in enhanced energy harvesting performance. We further show that this electrodynamic coupling can be strengthened using resonant harvesting circuits.

  6. Hyperbolic metamaterial lens with hydrodynamic nonlocal response.

    PubMed

    Yan, Wei; Mortensen, N Asger; Wubs, Martijn

    2013-06-17

    We investigate the effects of hydrodynamic nonlocal response in hyperbolic metamaterials (HMMs), focusing on the experimentally realizable parameter regime where unit cells are much smaller than an optical wavelength but much larger than the wavelengths of the longitudinal pressure waves of the free-electron plasma in the metal constituents. We derive the nonlocal corrections to the effective material parameters analytically, and illustrate the noticeable nonlocal effects on the dispersion curves numerically. As an application, we find that the focusing characteristics of a HMM lens in the local-response approximation and in the hydrodynamic Drude model can differ considerably. In particular, the optimal frequency for imaging in the nonlocal theory is blueshifted with respect to that in the local theory. Thus, to detect whether nonlocal response is at work in a hyperbolic metamaterial, we propose to measure the near-field distribution of a hyperbolic metamaterial lens. PMID:23787690

  7. HYDRODYNAMIC SIMULATION OF THE UPPER POTOMAC ESTUARY.

    USGS Publications Warehouse

    Schaffranck, Raymond W.

    1986-01-01

    Hydrodynamics of the upper extent of the Potomac Estuary between Indian Head and Morgantown, Md. , are simulated using a two-dimensional model. The model computes water-surface elevations and depth-averaged velocities by numerically integrating finite-difference forms of the equations of mass and momentum conservation using the alternating direction implicit method. The fundamental, non-linear, unsteady-flow equations, upon which the model is formulated, include additional terms to account for Coriolis acceleration and meteorological influences. Preliminary model/prototype data comparisons show agreement to within 9% for tidal flow volumes and phase differences within the measured-data-recording interval. Use of the model to investigate the hydrodynamics and certain aspects of transport within this Potomac Estuary reach is demonstrated. Refs.

  8. SPHGR: Smoothed-Particle Hydrodynamics Galaxy Reduction

    NASA Astrophysics Data System (ADS)

    Thompson, Robert

    2015-02-01

    SPHGR (Smoothed-Particle Hydrodynamics Galaxy Reduction) is a python based open-source framework for analyzing smoothed-particle hydrodynamic simulations. Its basic form can run a baryonic group finder to identify galaxies and a halo finder to identify dark matter halos; it can also assign said galaxies to their respective halos, calculate halo & galaxy global properties, and iterate through previous time steps to identify the most-massive progenitors of each halo and galaxy. Data about each individual halo and galaxy is collated and easy to access. SPHGR supports a wide range of simulations types including N-body, full cosmological volumes, and zoom-in runs. Support for multiple SPH code outputs is provided by pyGadgetReader (ascl:1411.001), mainly Gadget (ascl:0003.001) and TIPSY (ascl:1111.015).

  9. Hydrodynamics and electromyography: ergonomics aspects in aquatics.

    PubMed

    Clarys, J P

    1985-03-01

    In a quadruple approach we have suggested the ergonomics links between fundamental hydrodynamics, applied dynamics of swimming, electromyographical aspects and specific training. Fundamental and applied hydrodynamics were investigated in a Dutch Marine Ship model test station allowing for the measurement of passive drag in different positions and of active (swimming) drag. It was found that drag in a prone position under the water surface was greater than at the water surface, but active drag while swimming reached twice the drag values of any passive drag condition. This indicates that body form has no influence on drag and propulsion. Since it is merely the technical execution of the swimming movement that will influence performance, telemetric EMG of the involved musculature has allowed a complete kinesiological picture of the front crawl movements to be made. This knowledge is basic for the study of specific and alternative training systems, such as specific dry land training.

  10. The Radiation Transport Conundrum in Radiation Hydrodynamics

    SciTech Connect

    Castor, J I

    2005-03-18

    The summary of this paper is: (1) The conundrum in the title is whether to treat radiation in the lab frame or the comoving frame in a radiation-hydrodynamic problem; (2) Several of the difficulties are associated with combining a somewhat relativistic treatment of radiation with a non-relativistic treatment of hydrodynamics; (3) The principal problem is a tradeoff between easily obtaining the correct diffusion limit and describing free-streaming radiation with the correct wave speed; (4) The computational problems of the comoving-frame formulation in more than one dimension, and the difficulty of obtaining both exact conservation and full u/c accuracy argue against this method; (5) As the interest in multi-D increases, as well as the power of computers, the lab-frame method is becoming more attractive; and (6) The Monte Carlo method combines the advantages of both lab-frame and comoving-frame approaches, its only disadvantage being cost.

  11. Structure and hydrodynamics of colloidal systems

    SciTech Connect

    Hayter, J.B.

    1985-07-01

    Colloidal phases (for example, micellar solutions, latex suspensions, ferrofluids and microemulsions) provide excellent model systems with which to test structural and hydrodynamic theories of the liquid state. Interparticle potentials may be attractive or repulsive, and the experimentalist is often free to control the strength, range and symmetry of the interactions. Small-angle neutron scattering (SANS) and small-angle neutron spin-echo (SANSE) provide excellent complementary tools for studying the structure and time-dependence of these systems, where correlation lengths typically vary from about one to several tens of nm. Correlation times are usually in the nsec to ..mu..sec range, but may be of order minutes in certain systems. This paper will review some of the current theories and their recent experimental tests, using colloidal systems in which the direct interaction potentials may have spherical, dipolar or cylindrical symmetry and the hydrodynamic interactions may be weak or strong.

  12. Protostellar Collapse Using Multigroup Radiation Hydrodynamics

    NASA Astrophysics Data System (ADS)

    Vaytet, N.; Chabrier, G.; Audit, E.; Commerçon, B.; Masson, J.; González, M.; Ferguson, J.; Delahaye, F.

    2015-10-01

    Many simulations of protostellar collapse make use of a grey treatment of radiative transfer coupled to the hydrodynamics. However, interstellar gas and dust opacities present large variations as a function of frequency. In this paper, we present multigroup radiation hydrodynamics simulations of the collapse of a spherically symmetric cloud and the formation of the first and second Larson cores. We have used a non-ideal gas equation of state as well as an extensive set of spectral opacities. Small differences between grey and multigroup simulations were observed. The first and second core accretion shocks were found to be super- and sub-critical, respectively. Varying the initial size and mass of the parent cloud had little impact on the core properties (especially for the second core). We finally present early results from 3D simulations that were performed using the RAMSES code.

  13. Hydrodynamic Object Recognition: When Multipoles Count

    NASA Astrophysics Data System (ADS)

    Sichert, Andreas B.; Bamler, Robert; van Hemmen, J. Leo

    2009-02-01

    The lateral-line system is a unique mechanosensory facility of aquatic animals that enables them not only to localize prey, predator, obstacles, and conspecifics, but also to recognize hydrodynamic objects. Here we present an explicit model explaining how aquatic animals such as fish can distinguish differently shaped submerged moving objects. Our model is based on the hydrodynamic multipole expansion and uses the unambiguous set of multipole components to identify the corresponding object. Furthermore, we show that within the natural range of one fish length the velocity field contains far more information than that due to a dipole. Finally, the model we present is easy to implement both neuronally and technically, and agrees well with available neuronal, physiological, and behavioral data on the lateral-line system.

  14. RADIOGRAPHIC AND ANATOMIC CHARACTERISTICS OF DORSAL HOOF WALL LAYERS IN NONLAMINITIC HORSES.

    PubMed

    Goulet, Catherine; Olive, Julien; Rossier, Yves; Beauchamp, Guy

    2015-01-01

    Early radiographic diagnosis of acute laminitis is important for treatment planning and prognosis in horses. While four histopathologic layers make up the hoof wall, only two layers are distinguished on digital radiographs of horses' hooves. Objectives of this descriptive study were to determine which macroscopic layers correspond to the two radiographically visible layers, and to describe radiographic layer measurements in a group of clinically sound Warmblood horses. Twelve ex vivo equine hooves were examined at three different levels of the dorsal hoof wall. The four macroscopic layers were variably grouped and compared with radiographic layers. Stratum externum and stratum medium represented the superficial radiographic layer while stratum internum and dermis parietis represented the deep layer. In 27 clinically sound horses (54 thoracic feet), the superficial radiographic layer represented 64.3% ± 3.6% of the total dorsal hoof wall. Findings from this study provided baseline information for future studies of horses with acute laminitis.

  15. RADIOGRAPHIC AND ANATOMIC CHARACTERISTICS OF DORSAL HOOF WALL LAYERS IN NONLAMINITIC HORSES.

    PubMed

    Goulet, Catherine; Olive, Julien; Rossier, Yves; Beauchamp, Guy

    2015-01-01

    Early radiographic diagnosis of acute laminitis is important for treatment planning and prognosis in horses. While four histopathologic layers make up the hoof wall, only two layers are distinguished on digital radiographs of horses' hooves. Objectives of this descriptive study were to determine which macroscopic layers correspond to the two radiographically visible layers, and to describe radiographic layer measurements in a group of clinically sound Warmblood horses. Twelve ex vivo equine hooves were examined at three different levels of the dorsal hoof wall. The four macroscopic layers were variably grouped and compared with radiographic layers. Stratum externum and stratum medium represented the superficial radiographic layer while stratum internum and dermis parietis represented the deep layer. In 27 clinically sound horses (54 thoracic feet), the superficial radiographic layer represented 64.3% ± 3.6% of the total dorsal hoof wall. Findings from this study provided baseline information for future studies of horses with acute laminitis. PMID:26226838

  16. Actuator assembly including a single axis of rotation locking member

    DOEpatents

    Quitmeyer, James N.; Benson, Dwayne M.; Geck, Kellan P.

    2009-12-08

    An actuator assembly including an actuator housing assembly and a single axis of rotation locking member fixedly attached to a portion of the actuator housing assembly and an external mounting structure. The single axis of rotation locking member restricting rotational movement of the actuator housing assembly about at least one axis. The single axis of rotation locking member is coupled at a first end to the actuator housing assembly about a Y axis and at a 90.degree. angle to an X and Z axis providing rotation of the actuator housing assembly about the Y axis. The single axis of rotation locking member is coupled at a second end to a mounting structure, and more particularly a mounting pin, about an X axis and at a 90.degree. angle to a Y and Z axis providing rotation of the actuator housing assembly about the X axis. The actuator assembly is thereby restricted from rotation about the Z axis.

  17. Laser driven hydrodynamic instability experiments. Revision 1

    SciTech Connect

    Remington, B.A.; Weber, S.V.; Haan, S.W.; Kilkenny, J.D.; Glendinning, S.G.; Wallace, R.J.; Goldstein, W.H.; Wilson, B.G.; Nash, J.K.

    1993-02-17

    An extensive series of experiments has been conducted on the Nova laser to measure hydrodynamic instabilities in planar foils accelerated by x-ray ablation. Single mode experiments allow a measurement of the fundamental growth rates from the linear well into the nonlinear regime. Two-mode foils allow a first direct observation of mode coupling. Surface-finish experiments allow a measurement of the evolution of a broad spectrum of random initial modes.

  18. The Quantum Hydrodynamic Description of Tunneling

    SciTech Connect

    Kendrick, Brian K.

    2012-06-15

    The quantum hydrodynamic approach is based on the de Broglie-Bohm formulation of quantum mechanics. The resulting fluid-like equations of motion describe the flow of probability and an accurate solution to these equations is equivalent to solving the time-dependent Schroedinger equation. Furthermore, the hydrodynamic approach provides new insight into the mechanisms as well as an alternative computational approach for treating tunneling phenomena. New concepts include well-defined 'quantum trajectories', 'quantum potential', and 'quantum force' all of which have classical analogues. The quantum potential and its associated force give rise to all quantum mechanical effects such as zero point energy, tunneling, and interference. A new numerical approach called the Iterative Finite Difference Method (IFDM) will be discussed. The IFDM is used to solve the set of non-linear coupled hydrodynamic equations. It is 2nd-order accurate in both space and time and exhibits exponential convergence with respect to the iteration count. The stability and computational efficiency of the IFDM is significantly improved by using a 'smart' Eulerian grid which has the same computational advantages as a Lagrangian or Arbitrary Lagrangian Eulerian (ALE) grid. The IFDM is also capable of treating anharmonic potentials. Example calculations using the IFDM will be presented which include: a one-dimensional Gaussian wave packet tunneling through an Eckart barrier, a one-dimensional bound-state Morse oscillator, and a two-dimensional (2D) model collinear reaction using an anharmonic potential energy surface. Approximate treatments of the quantum hydrodynamic equations will also be discussed which could allow scaling of the calculations to hundreds of degrees of freedom which is important for treating tunneling phenomena in condensed phase systems.

  19. VH-1: Multidimensional ideal compressible hydrodynamics code

    NASA Astrophysics Data System (ADS)

    Hawley, John; Blondin, John; Lindahl, Greg; Lufkin, Eric

    2012-04-01

    VH-1 is a multidimensional ideal compressible hydrodynamics code written in FORTRAN for use on any computing platform, from desktop workstations to supercomputers. It uses a Lagrangian remap version of the Piecewise Parabolic Method developed by Paul Woodward and Phil Colella in their 1984 paper. VH-1 comes in a variety of versions, from a simple one-dimensional serial variant to a multi-dimensional version scalable to thousands of processors.

  20. Novel techniques for slurry bubble column hydrodynamics

    SciTech Connect

    Dudukovic, M.P.

    1999-05-14

    The objective of this cooperative research effort between Washington University, Ohio State University and Exxon Research Engineering Company was to improve the knowledge base for scale-up and operation of slurry bubble column reactors for syngas conversion and other coal conversion processes by increased reliance on experimentally verified hydrodynamic models. During the first year (July 1, 1995--June 30, 1996) of this three year program novel experimental tools (computer aided radioactive particle tracking (CARPT), particle image velocimetry (PIV), heat probe, optical fiber probe and gamma ray tomography) were developed and tuned for measurement of pertinent hydrodynamic quantities, such as velocity field, holdup distribution, heat transfer and bubble size. The accomplishments were delineated in the First Technical Annual Report. The second year (July, 1996--June 30, 1997) was spent on further development and tuning of the novel experimental tools (e.g., development of Monte Carlo calibration for CARPT, optical probe development), building up the hydrodynamic data base using these tools and comparison of the two techniques (PIV and CARPT) for determination of liquid velocities. A phenomenological model for gas and liquid backmixing was also developed. All accomplishments were summarized in the Second Annual Technical Report. During the third and final year of the program (July 1, 1997--June 30, 1998) and during the nine months no cost extension, the high pressure facility was completed and a set of data was taken at high pressure conditions. Both PIV, CT and CARPT were used. More fundamental hydrodynamic modeling was also undertaken and model predictions were compared to data. The accomplishments for this period are summarized in this report.